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A P P R O A C H O N L I N E

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C a t h L a b R e f e r r a l

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S u r g e r y R e f e r r a l

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C A R A T

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DIH Services Ltd. © 2014 and its licensors. All rights reserved.

CARAT Tutorials

CARAT™

Coronary Artery Reporting and Archiving Tool

Disclaimer

The content of this manual is provided for information purposes only, and is subject to change without notice. The collection of this information may be restricted by the privacy act of the provincial/territorial jurisdiction. The APPROACH software follows standardized definitions from the Canadian Cardiovascular Society (CCS), the American College of Cardiology National Cardiovascular Data Registry (ACC-NCDR), and the Society of Thoracic Surgeons (STS) national databases. These definitions may change from date of printing. DIH Services Ltd is committed to standardizing definitions. The content of this manual in no way represents an obligation, implied or otherwise, on the part of DIH Services Ltd. to include, maintain, and support every feature discussed in this edition.

Furthermore, DIH Services Ltd. assumes no liability for errors or omissions that may appear in this instructional resource.

The content of this instructional manual is protected under copyright. No part of this manual may be reproduced or transmitted in any form, including print, electronic, or otherwise without prior, written permission from DIH Services Ltd.

ISBN: Pending

Printed in Canada

Quickstart 1: Draw Your First CARAT Diagram 1

Quickstart 2: CARAT Tools 3

Quickstart 3: Template Selection Icons 5

Tutorial 1: Navigating CARAT 7

Tutorial 2: File Handling 15

The ‘File’ Options 15Saving and Printing 17

Tutorial 3: Percutaneous Coronary Intervention 19

Stenting Variations 19Balloon Angioplasty (POBA) Documentation 26Key Points 28

Tutorial 4: Branch & Segment Modification 29

Why Modify? 29‘Move Branch’ Function 29Branch / Segment Configuration Options 31‘Branch Pair’ Options 33Edit Vessel Function 34Key Points 36

Contents

Tutorial 5: Myocardial Jeopardy 37

Tutorial 6: CT Angiography 49

Suitability of CARAT for CT Reporting 49Selection of CT Module Within CARAT 51Visualization Quality 52Lesion Reporting 54

Tutorial 7: Coronary Segments & Branch Variants 57

Tutorial 8: Coronary Artery Total Occlusion 81

Coronary Scoring Systems: A Historical Perspective 93

Background 93Classifying Lesion Severity – What’s in a number? 93Myocardial Jeopardy – A critical dimension 95Challenges in quantifying septal coronary flow 96Toward an optimal myocardium-focused coronary reporting tool 96

Contents

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Quickstart 1: Draw Your First CARAT Diagram

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CARAT Tutorials

APPROACH © and DIH Services Ltd.

About APPROACH

The APPROACH software is designed to assist with the APPROACH mandate – to collect and process health information to improve cardiac care. Information on tests, patient status, indications and procedural data should be entered.

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‘Draw’ a lesion on an artery:

Left-click and hold within the borders of any vessel, then, moving proximal to distal, apply a lesion to the vessel. Be sure to stay within the vessel boundaries while applying the lesion.

Left-click on the text box at the bottom of the diagram to include clinical comments, then left-click Okay.

Click ‘Print’ to create a local hardcopy, then follow your browser’s print dialogue.

Right-click on the lesion to see the detail menu, then select a 90% blockage.

Notice affect to flow regions.

Left-click ‘Save’ to write the changes to the CARAT server. Notice the update notification on the status bar.

Key Points:

• The active ‘Edit Mode’ is shown in the lower left-hand corner status bar.

• Stay within vessel boundaries when drawing disease elements or other vessel features.

• Vessel features must be drawn from proximal to distal.

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Quickstart 2: CARAT Tools

About APPROACH



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CARAT ToolsCARAT QUICKSTART GUIDE 2:

The CARAT Icon

The CARAT button is found on the Cath page, the PCI page, and the Surgery page.

Drawing Mode Selection

Right-click the diagram canvas outside of any vessel boundaries to reveal the drawing made menu, then left-click to select drawing mode.

CARAT Status Bar

The status bar lets you know which drawing mode you are in, and provides useful tips on using your current drawing mode.

Zoom

Use your mouse’s scroll wheel to zoom in or our of the diagram. This can be particularly handy when drawing vessel details onto the smaller vessels.

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About APPROACH


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LegendLesion

Vis. Disease <40%

Calcium

Thrombus

Dissection

Ectasia

Stent

Positive Remodel

Timi III

Timi II

Timi I

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Drawing

To draw a vessel feature, left-click within a vessel boundary and, holding the left mouse button down, draw the feature from proximal to distal.

Secondary Menu

Right-click on a drawn vessel feature to access the secondary details menu.

Vessel Features

The various vessel features available are listed in the legend to the right.

Starting Over

To clear all drawn features and reset the template, select ‘Clear Selection’ from the Edit Menu.

Not Selected

Selected

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Quickstart 3: Template Selection Icons

About APPROACH



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Template Selection IconsCARAT QUICKSTART GUIDE 3:

Proceed Without Defaults

Select this icon to activate the flexible and individualized coronary tree assembly process.

Tab Selection Order

Once Proceed Without Defaults is selected, tabs are sequentially presented for ease of use.

“Oops, I made a mistake!”

Each template selection is immediately incorporated into the evolving picture on the left. This provides immediate feedback on the accuracy of the selection made. To select a different icon, the incorrect icon must be selected again to clear its choice, then find a replacement.

Template Selection Tabs

A coronary picture evolves on the left half of the CARAT window as segment and branch options are selected from the option icons shown on the right. Icons are grouped under these tabs (top right). A LAO Cranial projection is used for the final coronary rendering, a commonly used angiographic view perpendicular to the heart’s long axis. All coronary segments are well seen and understandable in this view.

However, it is possible to manually change the order by left-clicking on a desired tab.

Note: The Dominance tab MUST BE selected early, as the shape of IV Groove and PL segments and branch options vary by dominance.

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About APPROACH


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• Dashed Blue Lines: LV segment boundaries on the septum andthe back of the heart.

• Numbers: Size of branch (number of LV segments supplied).

• Shaded Grey: LV segments supplied by red segment or branchselections.

• Icon Background Colour:(a) White - Common available configuration;(b) Yellow - Anomalous coronary configuration;(c) Grey Option that is not available as it conflicts with one or more previous icon selections.

• Please note the Template Selection icons follow a differentconvention for conveying 3D than does the main CARAT diagram - The icons use solid or dotted lines to differentiate between the front and the back of the heart, whereas the main diagram uses different colours of vessel.

Bubble Help (Icon Tooltips)

When the mouse pointer hovers over the icons, a ‘bubble help’ box appears describing the coronary segment or branch selection, the branch sizes, and the myocardial areas supplied. (Example: Help pop-up associated with the icon selection example in 3).

Icon Components

• Red Outlines: Coronary segmentsor branches that will be added to the picture if this icon is selected.

• Solid Blue Lines: LV segmentboundaries on the front of the heart.

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Tutorial 1: Navigating CARAT

Step 1 - Select the Report (Diagram) Type:

Select the type of report desired (Angiography, CTA, PCI or CABG) by selecting:

‘File’ > ‘Report Heading’.

Figure 1: Selecting a report type.

Step 2 – Set Templates and Basic Native Anatomy:

The reporting process begins during the angiogram itself. Attention should be paid to dominance, type of LAD, patterns of side-branches in the anterior, marginal, and posterolateral regions of the free LV wall, as well as anomalous vessel origins and pathways. The CARAT construction process is based upon the sequential selection of templates that most closely resemble the patterns observed during the angiogram or the angiographic review.

The template groupings are filed under the tabs seen along the top of the right portion of the screen.

The initial, ‘Welcome’ screen asks if the operator wishes to begin by using complete or partial default renderings. The default options have some advantages in reducing reporting time, but it is recommended that the ‘Proceed Without Defaults’ option be used until the operator is familiar with the tab sequence.

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Figure 2a: The CARAT welcome screen.

With each successive template selection, a new set of templates is presented, and the most appropriate of these is selected by a left mouse-click. As the selection process proceeds, a picture progressively emerges on the drawing area to the left. It is not necessary to follow the tab sequence as presented.

The template options are loosely organized by branch location and branch size (the size number reflects the approximate number of segments from the 17-segment model supplied by the branch). Hovering the mouse pointer over an option opens a mouse-over box, which describes the option (This only happens if the option is selected).

Finally, options that reflect an anomalous origin or pathway of a segment or branch are shown on a yellow background.

Once the basic anatomy is decided upon, options are available to further refine side-branch and segment detail. These options can be seen by right-clicking on the segment that you wish to change. (As shown in Figure 2b, the operator is contemplating altering a posterolateral branch. There are a number of branching configurations and branch sizes to chose from as seen in the drop-down menu.)

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Figure 2b: Refining side-branch detail.

Branch editing will be discussed in more detail in a subsequent tutorial.

Step 3 – Locate the CARAT Taskbar:

The ‘CARAT Task Bar’ is located along the lower perimeter of the window.

Figure 3: The CARAT taskbar highlighted at bottom.

The lower-left corner reminds you which ‘Edit Mode’ you are in, while the section to the right tells you what the functions of the left and right mouse buttons are in this mode.Right-click on any open area on the diagram to exit the current ‘Edit Mode’.

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Step 4 – Begin Entering Arterial Detail:

When the basic, native anatomy is decided upon, disease and intervention detail can be entered. This descriptive function is initiated by right-clicking the mouse on the drawing area (but not on the artery segments). A menu list is revealed as shown, and an item is selected by left-clicking the desired item (in this example the ‘Lesion’ Edit Mode).

Figure 4: Diesease and intervention detail menu.

The lesion (or other menu selection) is placed upon the diagram by clicking and holding the left mouse button as the disease element/stent is ‘drawn’ along the vessel. This must be done from proximal to distal.

In addition, caution must be taken to make sure that the mouse button is activated and released within the boundaries of the artery. When working in small spaces, the ‘Zoom’ function can be extremely helpful - Use your mouse’s scroll function to do so.

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Step 5 – Locate the Secondary Menus:

In most cases, a secondary, drop-down menu is available for each menu item identifying options for greater item detail. (The example given is the ‘Lesion’ sub-menu).

Figure 5: Choosing greater item detail options.

A lesion severity of 50% is selected by default, but this value can be subsequently changed to any of the options shown, 80% in this example.

In addition, tertiary submenus are available to identify Culprit lesions and reasons for this decision, Lesion Features, FFR measurements, and Area at Risk detail. These tertiary menus are opened by left-clicking the desired item and then right-clicking on the features for details that you wish to record.

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Step 6 – Place Surgical Grafts:

Surgical graft placement is facilitated by selecting ‘Grafts’ on the main edit menu. When this selection is made, available graft targets are shown on the diagram.

Figure 6: Choosing the graft-type options.

At this point, the desired graft target is selected with a mouse ‘right-click’, revealing the graft-type options available. The graft-type option selection is made with a mouse left-click and the graft is drawn.

This topic is dealt with in more detail in a separate tutorial.

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Step 7 – Draw Stents:

After selecting “Stent” from the main menu, the stent is drawn, proximal to distal, using the left mouse button, again ensuring that the mouse point stays within the stented segment.

Figure 7a: The stent procedure detail menu.

After the stent is placed, a detailed accounting of the stenting procedure can be documented by right-clicking the lesion and selecting Procedure Detail which will in turn display the Intervention Detail drop-down window.

Detail on Access used, device detail and specific strategies can be selected by strategic ‘left-clicking’ on the desired choices. Entries from this menu will be displayed as a ‘Stent Summary’ on the upper left corner of the report. See figure 7b.

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Figure 7b: The stent procedure accounting summary.

This topic is dealt with in more detail in a separate tutorial.

It is hoped that this brief introduction to the navigation possibilities within CARAT will allow interested parties to gain an appreciation for the potential of this tool. This trial version of CARAT contains full functionality; only the archiving and reporting aspects are missing.Key Points:

• The active ‘Edit Mode’ is shown in the lower left-hand corner.

• Stay within vessel boundaries when entering disease elements.

Diagrams generated by the CARAT trial version can be saved and exported in pdf format.

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Tutorial 2: File Handling

The ‘File’ Options

The first step in report preparation is to select the type of procedure under ‘File’ on the menu bar.

Figure 1.

Each report type activates slightly different functionality as will become evident in the various tutorials.

The trial version of CARAT allows you to enter basic patient information (Figure 2), as well as the indication for the procedure (Figure 3).

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Figure 2.

The patient detail will appear in the report header and the indication will be inserted in the ‘Comments’ section.

Figure 3.

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Saving and Printing

The trial version of this software allows you to save the report in pdf format and print.

Figure 4.

Previously saved reports cannot be recalled for editing and there are no archiving or reporting capabilities.

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Tutorial 3: Percutaneous Coronary Intervention

Stenting Variations

We will use a complex LAD bifurcation stent procedure to illustrate the CARAT stent documentation process, specifically a Culotte procedure:

First, the ‘Edit Menu’ is opened by right-clicking on a free part of the drawing area.

‘Stent’ is then selected, and the ‘Stent Edit Mode’ is shown to be active in the lower left corner of the screen. Click and hold the left mouse button and trace the first stent, proximal to distal, from the proximal LAD into the proximal diagonal. The stent being edited or described is shown in pink; stents that are inactive and not being modified are shown in blue.

Figure 1.

The next step is to right-click on the stent and select ‘Interventional Detail’ (see Figure 1). On the top of the Interventional Detail drop-down the point of origin and termination of the stenting procedure is automatically specified. In the middle of the drop-down menu ‘Devices’ is then selected. You are now ready to document the sequence of events during the Culotte procedure.

Predilatation of the proximal LAD and proximal diagonal lesions is performed and documented by selecting ‘Balloon’ under ‘Device Type’; select the balloon used from the drop-down menu and enter diameter, length, and pressure detail.

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Next, ‘Add’ is selected, the ‘Device Type’ is changed to ‘Stent’, and ‘Device Model’ and parameters are entered as shown (Figure 2).

Figure 2.

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The final step (with respect to this stent) was to post-dilate. This is documented by selecting ‘Add’, then ‘Balloon’ under ‘Device Type’ and finally the balloon size and inflation particulars (Figure 3). When done, select “OK”.

Figure 3.

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The second stent is then drawn from a point close to the heel of the previous stent, but now extending past the second LAD lesion (Figure 4). Again notice that the origin and termination points of this second stent are automatically recorded.

Figure 4.

The ‘Interventional Detail’ option is selected after right-clicking on the new stent. The first step is to document the pre-dilatation by selecting ‘Balloon’ under Device Type and entering the balloon deployment particulars (Figure 4).

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Next, ‘Add’ is selected and ‘Stent’ is chosen as the ‘Device Type’. Once again, the ‘Device Model’ and deployment details are entered, as in Figure 5.

Figure 5.

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Finally, the post-dilatation balloon is documented by selecting ‘Add’, then selecting ‘Balloon’, then finally selecting the Device ‘Model’ and deployment particulars (see Figure 6).

Figure 6.

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At this point, we also want to document that this was indeed a bifurcation procedure and we wish to specify the strategy used. (See Figure 7) ‘Culotte’ is selected in the ‘Bifurcation’ Strategy section, and we will also specify that a Kissing Balloon procedure was used.

Figure 7.

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Balloon Angioplasty (POBA) Documentation

Interventional procedures that do not use a stent are entered in a different way. Specifically, this is accomplished while in the ‘Lesion Edit Mode’, rather than the ‘Stent Edit Mode’. In this example an 80% circumflex lesion is the POBA target (Figure 8 and 9).

Figure 8.

The lesion intervened upon is right-clicked and the ‘Intervention Detail’ option is selected as shown in Figure 8 for this mid-circumflex 80% lesion.

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Figure 9.

The ‘Devices’ menu tab is selected, allowing entry of the procedure detail in a manner similar to that described for stenting (Figure 9).

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After the POBA procedure, the lesion intervened upon is designated by the letter “B” at the site of the lesion, and the device and pre and post lesion detail is filed on the final report’s ‘Balloon Summary’ table (Figure 10).

All of the information entered is now carefully tabulated in the ‘Stent and Balloon Tables’ in the upper left portion of the report, while other important information on the technique used is automatically recorded in the ‘Comments’ section below.

Figure 10.

Key Points

• Stents should be drawn from proximal to distal while in the ‘Stent Edit Mode’.

• Sequential procedural detail is presented in table on the report. Our deliberate attempt is to present all anatomic and procedural detail on a single page.

• If a patient returns for another procedure in the future, only stent information is carried forward from the intervention description.

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Tutorial 4: Branch & Segment Modification

Why Modify?

Well, because we all want the diagram to be as helpful and accurate as possible.

Branch options presented with the Template Tabs on the right half of the CARAT window are limited to unbranched selections with standard sizing (1 to 3 myocardial segments supplied) and standard locations (basal, mid and apical locations for diagonal, ALM and ILM for marginal branches and medial and lateral locations for posterolateral branches). When more detail is needed to convey clinically important anatomic variation, ‘right clicking’ on a branch or segment in need of modification exposes a new menu of modification options. This tutorial highlights several opportunities available.

A comprehensive and useful angiographic report should not attempt to replicate every feature of a patient’s coronary anatomy as individual variability is too great and many features are of little clinical consequence. However, many details are of value and every attempt should be made to capture and characterize those of clinical and procedural relevance.

‘Move Branch’ Function

When a branch origin requires modification, the ‘Move Branch’ function can be selected after right-clicking on the branch requiring an adjustment. As an illustration, observe the proximal marginal in Figure 1 and notice the branch location with respect to the 80% LCx lesion.

Figure 1.

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If you wish to move the anterolateral marginal branch closer to the LM, place the mouse arrow on the branch between the first two nodes (Figure 2), click and hold the left mouse button, and drag the vessel to the desired new location (Figure 3).

Figure 2.

Figure 3.

(Notice that Reduced Flow Regions on the 17-segment circumferential polar plot and the APPROACH Jeopardy score in the upper right corner automatically changed to reflect the new side branch location with respect to the 80% lesion.)

It is important to keep the first node of the branch being moved within the boundaries of the parent vessel. This function is intended only to alter a branch origin: it does not change the myocardial distribution assigned to the branch.

After the branch has been moved, it is possible (in the same menu selection) to grab on to and move other nodes along the length of the artery to make a more favorable appearance and to avoid overlapping other vessels or disease elements.

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Branch / Segment Configuration Options

The top portion of the menu exposed by left-clicking on a branch or segment to be altered provides a list of alternate configuration choices (Figure 4). (Try selecting each one to learn the configuration options that are available.)

Figure 4.

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In this example, we have selected a configuration that branches proximally with symmetric arms (Figure 5), but multiple other options with varying branching configurations and pathways are also available to portray clinically important variations.

Figure 5.

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‘Branch Pair’ Options

The standard basal, mid, and apical branch placements establish a fixed relationship between branches and myocardial regions. (This will be described in greater detail in the Myocardial Jeopardy Tutorial).

Occasionally, however, a pair of branches may actually originate from a single basal, mid, or apical location. This paired or Dual branching option is included in the Figure 4 drop-down menu presenting an opportunity to portray a pair of branches within a single region. (See Figure 6).

Figure 6.

This action effectively creates a second proximal diagonal, and the software then assumes that the two new branches now share equally the myocardial region supplied by the originally unbranched proximal diagonal.

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Edit Vessel Function

The last item on the configuration menu, Edit Vessel, opens a wide range of vessel segment editing possibilities (largely beyond the scope of this review). We advise that the edit option be used with caution, at least until the operator is comfortable with pre-formed options available.

When Edit Vessel is selected and a vessel for editing is right-clicked, a second drop-down menu is presented as in Figure 7. As shown, this menu allows you to reposition labels, move assigned bypass graft target locations and add explanatory text to the diagram. (Altering a default bypass graft target location is the most common use of the Edit Vessel menu.)

From this menu you can also select Edit Line with yet another drop-down menu shown in Figure 8 that presents the ability to move and delete nodes, extend the length of a line segment and make other changes to Drawing Properties of lines as shown in Figure 9. These edit functions are most useful in portraying clinically important morphology variations, such as a severe RCA Shepherds Hook, tortuosity in a diseased segment, or important angulation variations at a bifurcation lesion.

Figure 7.

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Figure 8.

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In CARAT, Vessels (for example a diagonal or a marginal branch) are composed of lines, each line designating the portion of a vessel that passes over a single LV myocardial segment (see green arrow in Figures 8 and 9 representing the portion of the branching basal ramus branch that passes over the mid anterolateral region 12).

Figure 9.

The Line Properties submenu defines graphic features of lines and, most importantly, indicates the LV segment, and portion thereof, to which the line is assigned (key to the automated myocardial jeopardy calculation process).

Key Points

• Moving a segment or branch will alter the origin but not the distribution region of the segment or branch.

• Use the ‘Edit Vessel’ function only when the desired change is clinically important and when the desired appearance cannot be achieved by a default configuration change.

• If you get too ‘off-track’ in your editing, it is best to reselect the starting branch template in question and try again.

• If you cannot access the menu you want, chances are you are still in a previous ‘Edit Mode’. Check the taskbar on the lower left corner of the screen to confirm. This corner ‘Edit Mode’ box must be empty before the branch configuration editing functions can be activated.

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Tutorial 5: Myocardial Jeopardy

Exploring the quantitative and spatial utility of angiography

Although coronary angiography is primarily a descriptive tool, its ability to define more quantitative myocardi-al-coronary disease relationships continues to be explored. These explorations have been only modestly suc-cess as they arise from empiric anatomic assumptions that fail to capture the significant anatomic variability seen between patients. The CARAT software has attempted to capture this anatomic heterogeneity, hopefully leading to greater utility in small cohort and individual patient assessments.

Direct myocardial imaging techniques are reliable when anatomic or distinct biochemical or functional myo-cardial boundaries are present, but they are of little value in the absence of these delimiters and angiography may then play a role. Clinical situations in which angiography may have a quantitative advantage include:

• Assessment of the relative amount of myocardium subtended by disease vessels in the absence of isch-emia or myocardial injury.

• Quantitative assessment of completeness of revascularization after revascularization procedures.• Providing a descriptive link between arterial configurations and the 17-segment ventricular model adopted

by most other imaging techniques.

17 Segment Model

Unlike the anterolateral, obtuse marginal and posterolateral myocardial region designations used in most published quantitative angiographic models, CARAT has adopted the 17 spatial designations proposed by the Cardiac Imaging Committee of the AHA. (See figure 1 below). In this model the LV is divided into three (basal, mid and apical) slices of equal thickness from base to apex. Each slice contains free wall and septal seg-ments that are separated by the insertion points of the RV free wall. There are 11 free wall segments, 5 septal segments and a distinct apical (non-cavitary) segment.

We have completed precise CMR measurements of the size of each of the 16 free-wall and septal segments in a cohort of normal volunteers. Although the original assumption that each of the 16 segments constituted 6% of the LV myocardium was close, more precise measurements are now available and have been included in the CARAT Jeopardy calculation algorithm. These normal measurements are shown in the table below. Myocardial volume measurements excluding papillary muscles were used.

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The most effective graphic presentation of this model is one using a circumferential polar plot as indicated to the right of the diagram with the rings (from outside to inside) representing the basal, mid and apical layers and the center (area 17) the non-cavitary apex.

Figure 1: 17-Segment Model.

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LV Free Wall Branch Assumptions

• Number and size of free wall branches.

A major goal of CARAT is to link each side branch location and size to specific segments in the above 17-segment model. The reporting conventions of the CASS registry with respect to branch configurations have stood the test of time and, with minor modifications, are adopted in CARAT (Circulation 1981;63:I-1). In particular the specification of a maximum of 3 branches for each of the anterolateral, marginal and posterolateral regions, plus a tenth ramus intermedius branch, each with three size categories, has been adopted by CARAT. The basic CARAT assumption is that a Size 1 branch supplies the majority of one myocardial segment, a Size 2 branch supplies two segments and a Size 3 branch supplies three. (A similar assumption was made in the APPROACH Jeopardy score assessment derived from prospectively used Heartview© diagrams in which a strong correlation between the resulting score and one year mortal-ity was found in a cohort of 20,000 patients. M Graham et al Am Heart J 2006;142:254.)

• Location assumptions for free wall branches.

Diagonal, marginal and ramus side branches are assumed to follow an oblique course consistent with the usual direction of superficial myocardial fibers. Branches are designated as basal, mid or apical with respect to their points of origin along the LAD and anterolateral, inferolateral or inferior along the AV circumflex. We avoided ordinal numbering of branches to emphasize their spatial association with specific myocardial segments. These associations are shown on the charts below. In addition to the usual oblique configuration of free wall branches, distribution variants are occasionally seen in which the oblique direc-tion is not followed. The most common variants follow either axial or transverse directions for diagonal branches and a transverse direction for ALM branches. These options are highlighted in yellow along with their corresponding myocardial region assignments.

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Figure 2: Quantitative LV Assignments - Diagonal and Marginal Branches.

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Posterolateral Branch Assumptions

The table in figure 3 below specifies segmental myocardial assignments for the PDA as well as right, mid and left posterolateral branches. The PDA assignment procedure is unique. Unlike the anterior interventricular ar-tery (LAD), which makes its contribution to the anterior LV free wall through prominent diagonal branches, the PDA makes its important contributions to the adjacent inferior segments through channels that are very much less distinct. For this reason we have had to rely on the classic pathologic observations of Kalbfleish and Hort (Am Heart J 1977;94:183) to specify the quantitative and spatial contributions of the PDA to in the inferior and septal segments.

Figure 3: Quantitative LV Assignments - PDA and Posterolateral Branches.

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Septal Branch Assumptions

The picture in figure 4 below, from Bertho and Gagnon (Chest 1964;46:251), illustrates the usual balance be-tween perforating arteries to the septum from the posterior (white) and anterior (red) interventricular arteries. Although there is variability, the anterior (LAD) septal branches usually supply 2/3 of the septum. As shown in the picture, there tends to be a gradient in relative inferior and anterior septal contribution between the base and apex with the LAD assuming proportionately more responsibility for the septum as one proceeds toward the apex. CARAT assumes that the relative contribution remains the same from base to apex.

The 17-segment model proposes 5 septal segments, 2 basal, 2 mid and 1 apical. The basal and mid antero-septal segments and the anterior 25% of the basal and mid inferoseptal segments are supplied from the LAD. The remaining inferior 75% of the basal and mid inferoseptal segments are supplied by from the PDA perfora-tors. The apical septum blood supply is more difficult to specify as this area is determined to a large extent by the variable size balance between the LAD and PDA. We have specified that the distal LAD and PDA together supply the apical septum, 1/3 by distal PDA perforators and 2/3 by the distal LAD in a system with a Type 2 LAD, 100% from the PDA with a Type 1 LAD and 100% from the LAD with a Type 3 LAD.

Figure 4: PDA and LAD contribution to septum.

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Myocardial Assignment Process

As each coronary segment or branch is constructed in CARAT, specific properties are assigned to each component (line) that traverses a new LV segment. If a branch traverses more than one myocardial segment, myocardial values are assigned to each segment. This is a transparent process that can be seen by right-clicking on a branch of interest > right-clicking on ‘Edit Vessel’ > right-clicking on the LV segment of interest > selecting ‘Line properties’. You will then see a view (similar to the one shown in figure 5 below) with segment number and the weighting value (RMA) assigned – from 0 to 1.

Figure 5: Process of LV assignment to coronary segments.

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CARAT Tutorials

Initial Tally of Myocardial Assignments

In constructing the coronary tree, we ask operators to pick template combinations that best depict the loca-tion and distribution of branches and segments. We also ask that they designate branch sizes that indicate the desired size/distribution area relationship. It is not necessary to make template selections that yield a summed value for each segment of “1.0” in all cases, for we have included a reasonable equilibration process that adjusts for under and over-assignment of myocardial values to individual segments.

The first step in this equilibration process is to make a myocardial assignment tally based upon the tree dia-gram generated by the angiographer. Selecting File/Unadjusted RMA Form from the tool bar will reveal this tally. An example is shown in figure 6 below. Some segments have the optimal value of 1.0 but other regions have summed values that are less than or greater than unity. For these areas adjustments will be made.

Figure 6: Tally of assigned myocardial values.

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Myocardial Assignments Talley Adjustments

For segments such as 1, 6, 12, 4 and 14 in the above tally illustration, the total myocardial assignment from contributing branches has exceeded 1.0. When this occurs, the contribution from each vessel is proportion-ately reduced to end up with a final summed assignment of 1.0. When the contribution tally for one or more regions is less than 1.0, a different strategy is needed. Specifically a default arterial segment has been as-signed to each myocardial segment.

When a tally is less than 1.0, the unassigned value is given by default to pre-specified regions, as shown on the table in figure 7 below. (These defaults were derived from recent CMR-angiographic correlation work in a series of single-vessel STEMI patients. The report correlates infarct-related arteries to injured ventricular seg-ments from the 17-aegment model (JT Ortiz-Perez et al JACCImg 2008;1:282). Importantly, apical segments and the mid- anterolateral segment default to the LAD in all LAD-related STEMIs.

Figure 7: Default artery assignments for LV segments.

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Final Quantitative/Qualitative Myocardial Picture

The finished CARAT diagram provides an adjusted index of the amount of myocardium supplied by arter-ies that are narrowed by > 75% (or >50% in the case of the LM). The total jeopardy score is indicated in the upper right portion of the final CARAT diagram. In the example in figure 8 below, an acute inferior STEMI is described. The area supplied by the occluded RCA was calculated to be 31%, a designation that also can be displayed by right-clicking on the lesion of interest while in the ‘lesion’ editing mode and then select ‘Area at risk’. In this example there were other lesions greater than 70% in the LCA yielding the total jeopardy calcula-tion of 48%. The myocardial segments affected by lesions greater than 70% are highlighted on the circumfer-ential polar plot to the lower right.

Figure 8: Example report with jeopardy and area-at-risk scores.

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Sources of Error in Model

1. Branch length – myocardial volume relationship. The strongest theoretical association between branch size and the amount of myocardium subtended by a branch is based upon accurate assessment of vascular luminal area, a measurement that is not possible in the presence of coronary disease. The branch length-to-myocardial volume relationship has been carefully explored by C. Seller et al (Circ. 1992;85:1987) who demonstrated a strong relationship between the summed length of secondary plus tertiary branches (easily visible on angiography) and myocardium supplied. This summed value is not practical for clinical use either. The assumption made in CARAT, however, is that a dominant vessel crossing most of a myocardial segment will supply most of that segment, a significant oversimplification of the relationship described by Seller and in-troduces a potentially important source of error. The process used in CARAT of adjusting vessel contributions such that the total value for a segment does not exceed or fall short of unity should reduce, but not eliminate, the size of this error.

2. Attention to detail in vessel template selection. As a reporting tool increases in complexity, there is increas-ing dependence upon due care and attention of the operator as vessel template options and lesion features are selected. A reporting tool must ‘walk the balance’ between achieving inter-observer reproducibility yet capturing important complexities in individual coronary trees. Reporting consistency in CARAT is encouraged by the use of intuitive template options of basic coronary structure and by providing immediate diagram-matic feedback of selections made. To minimize errors, sub-branching complexity has been removed from initial template options with the freedom to add this complexity at a later stage by vessel editing functions as described in other tutorials.

3. Is CARAT too complex for widespread use? Most published quantitative coronary models are based upon common major epicardial coronary artery configurations that rarely capture the anatomic variations seen in individual patients. For this reason the utility of published models is limited to global observations in larger populations with little precision when applying the model to individuals or small patient cohorts. The CARAT methodology should allow greater precision, but the tool is somewhat complex and is not widely available. There will be an ongoing effort to clarify the methodology by making an interactive electronic spreadsheet available to all interested investigators. The document will allow ‘point-and-click’ selection of branch configura-tions and lesion locations with automatic myocardial volume calculations.

Disclaimer

Although the regional myocardial assignment and jeopardy values in CARAT are based upon reasonable assumptions, they are not derived from direct area or mass measurements. As such their precision, in rela-tive and in absolute terms can be questioned. Caution must be exercised in basing clinical decisions upon the specific numbers generated.

Despite this important disclaimer, the CARAT calculations and renderings can give useful insights into the myocardial regions affected by significant coronary lesions thereby allowing more informed integration of data from multiple imaging techniques. The CARAT data may also present useful insights into area at risk in acute coronary syndromes and into the completeness of revascularization after intervention, particularly when used in qualitative and relative terms.

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Tutorial 6: CT Angiography

Suitability of CARAT for CT Reporting

Of the many unique imaging capabilities of CT angiography, defining spatial relationships is clearly a highlight. Translation of these 3-D insights to paper is a challenge that CARAT meets. The “tree” image in Figure 1 illustrates a coronary artery spatial array with clear configuration insight.

Figure 1. - CT Tree Image.

(Although tree images are infrequently used in day-to-day CT analysis, this example illustrates the 3-D clarity of this imaging technique.)

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CARAT is able to give a credible portrayal of this anatomy (Figure 2).

Figure 2. - CARAT Rendering of Figure 1.

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Selection of CT Module Within CARAT

Selecting File > Report Heading on the Menu Bar reveals the types of reports available.

For this tutorial, selecting CT Report from this menu will activate the CARAT features unique to CT reporting.

Figure 3. - Accessing CT Report Features.

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Visualization Quality

Although the coronary tree is adequately seen in most CT angiograms, it is occasionally desirable to specify those distal, septal, or other unique situations in which visualization may be absent or suboptimal.

The CARAT Edit Menu, Figure 4, is accessed by right-clicking the tree diagram background. One of the options available is the Visualization feature.

Figure 4. - The CARAT Edit Menu and the “Visualization” Option.

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(When opening the Edit Menu, be careful to select the diagram background; right-clicking the arterial segments offers other options outlined below).

While in the Visualization mode, right-clicking on a coronary transition point where visualization quality changes reveals the Visualization submenu (shown in Figure 5).

Figure 5. - Visualization submenu. The ‘Not Seen’ option is selected for the distal LAD.

In the CT example in Figure 1, above, the distal LAD is not visualized - This fact is graphically portrayed on the CARAT diagram.

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Lesion Reporting

When the Lesion editing mode is selected from the CARAT Menu, lesions can be “drawn” onto the arterial segments by left-clicking, holding, and tracing the length of the lesion, from proximal to distal.

At this point, the lesion should be right-clicked to reveal the CT Lesion submenu (as shown in Figure 6). Lesion severity ranges are presented in keeping with the most current reporting guidelines.

Figure 6. - CT Lesion Submenu also showing CT Features selection option.

After the severity is selected, selecting CT Feature provides additional lesion character detail on the lesion submenu as shown. Specifically, lesions can be classified as soft, calcified, or mixed; a letter appearing after the numerical severity range shows this designation.

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As a reminder, the editing mode currently operative is shown in the lower left corner of the working area. To the right of this designation is a short description of the functionality of the left and right mouse keys while in that particular editing mode.

One additional coronary artery insight afforded by intravascular ultrasound and CT imaging is the important finding of positive remodeling.

This finding can be portrayed on the CARAT diagram (as shown in Figure 7), and is accomplished by the combined use of the Ectasia option superimposed on a lesion rendering.

Figure 7. - CARAT CT Depiction of Positive Remodeling.

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Tutorial 7: Coronary Segments & Branch Variants

Introduction

The coronary tree assembly stragegy of CARAT is a stepwise selection of coronary branches and sizes from template options presented under the tabs on the right half of the CARAT window. Branches selected from the template tabs are those that follow a ‘usual’ pathway or configuration and have no sub-branches. The secondary branch selection process described in this tutorial is intended to capture more branch detail when clinically important sub-branching patterns and pathway variants require documentation.

Secondary branch options and variants are revealed by ‘right-clicking’ on the branch or segment in need of alteration. An alternate selection is then made by ‘left-clicking’ on one of the options presented. (In order to see this secondary menu, a Menu Item cannot be active. Active Menu Items are shown in the space at the lower left corner of the CARAT window. If a Menu Item is present in this space, it must first be cleared by ‘left clicking’ on any open space on the assembly palate – left half of CARAT window.)

This tutorial describes branching options and variants for the following:

• RV and Acute Marginal Branches

• PDA Variants » Normal PDA (Type II LAD) Variants » Small PDA (Type III LAD) Variants » Large PDA (Type 1 LAD) Variants » Apical inferior IV groove ‘gap’ variants » IV groove ‘gap’ at apex or apical inferior region plus the apex o Type III LAD variants involving inferior IV groove

• Posterolateral branch variants » Single PL branch » Two PL branches

• Obtuse Marginal Branches » Anterolateral Marginals » Inferolateral Marginals

• Posterolateral and marginal arteries supply inferolateral LV segments

• Ramus Intermedius

• Diagonal Branches » Basal (proximal) diagonals » Mid diagonals » Distal (apical) diagonals

• Other variants (mid LAD, apical LAD, right and left AV groove)

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RV and Acute Marginal Branches

By default, a single mid-RCA RV branch plus an AM branch are included in the basic tree construction. However, there is clinical value in capturing several important variants of these branches.

It may be of value to show that the RV branch is particularly “Large”, “Small” or “Absent”. Also two varieties of “Dual” RV branches are offered. The most common is a proximal and mid-RCA pairing; however, a mid and distal pairing is useful to recognize and label. (This distal – posterior - RV free wall branch variant is often mistaken for the PDA with implication to revascularization planning.) RV branch variants are shown below.

Figure 1 - RV Branch Variants

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PDA Variants

The initial step in characterizing inferior and inferoseptal arteries begins with selection of the configuration of branches that supply the entire inter-ventricular groove. After dominance is decided upon, the related IV Groove tab is selected (see Figure 2).

The top three choices reflect the classsic balanced configurations of LAD and PDA (Types I, II and III). PDA variants for the large, normal and small PDA branches are shown in Figures 3, 4 and 5.

The two IV groove variants shown by the middle icons of Figure 2 represent the following scenarios: left, a Type II LAD is paired with a small PDA; and right, a Type I LAD is paired with a small PDA. In these cases the resulting ‘gap’ in the AV groove is supplied by an anomalous adjacent branch. (These options are shown in Figures 6 and 7.)

Figure 2 – IV Groove Configurations

The final two variants represent uncommon anomalies in which a Type I or II apical LAD originates from the proximal RCA.

(a) Normal PDA (Type II LAD) Variants

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The diagram below indicates the variants available for a ‘normal’ sized PDA. A normal PDA spans the basal, mid and apical thirds of the inferior IV groove.

Figure 3 – Normal PDA Variants

(b) Small PDA (Type III LAD) Variants

The diagram below indicates the variants available for a ‘small’ sized PDA. A small PDA spans the basal and mid thirds of the inferior IV groove with unbranched, branched and dual variants shown in Figure 4. In the lower right of Figure 4 is a special variant in which the PDA supplies only the basal portion of the AV groove accommodating an exceptionally large Type III LAD (also see Figure 8).

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Figure 4 – Small PDA Variants

(c) Large PDA (with small Type 1 LAD) Variants

The diagram below indicates the variants available for a ‘large’ sized PDA that spans the entire inferior IV groove AND wraps around the apex to cover a variable amount of the apical anterior IV groove.

The first variant (left) includes a prominent branch supplying the apical inferior LV segment while the second contains a double (‘serpent’s tongue’) configuration at the apex. Although clearly not large PDA variants, the two options on the right allow for operational short-cuts during the assembly process. Specifically, these options allow transitioning from a Type I IV Groove tab to one of the IV groove “gap” configurations shown in Figures 6 and 7.

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Figure 5 – Large PDA Variants

(d) Apical inferior IV groove ‘gap’

As indicated in the left central icon in Figure 2, certain IV groove configurations require branches other than the LAD and PDA to complete the interventricular groove pathway. ‘Right-click’ on the branch that is felt to supply the distal PDA “gap” territory. From the branching options list, select the configuration that applies. The four branches that can supply the distal PDA territory are, from left to right, the RV branch, acute marginal, right posterolateral and obtuse marginal.

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Figure 6 - ‘Remote’ supply of distal PDA

(e) IV groove ‘gap’ at apex (also apical inferior region plus the apex)

As indicated in the right central icon of Figure 2, a supply ‘gap’ can exist in the apex or apex plus apical inferior section of the IV groove. Figure 7 indicates one adjacent branch (acute marginal) and one more remote branch (anterolateral obtuse marginal) that can fill this gap.

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Figure 7 - ‘Remote’ supply of distal PDA + Apex

(f) Type III LAD variants involving inferior IV groove

A Type III LAD supplies the non-cavitary apex and most of the apical inferior segment of the IV groove. In some cases the LAD is even longer, supplying the mid and even the basal portions of the inferior IV groove. Creating these configurations requires an adjustment to the distal LAD and to the small PDA as shown in Figure 8. (The menus in the upper left and upper right of Figure 8 are obtained by ‘left- clicking’ on the distal type III LAD and small PDA, respectively.)

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Figure 8 - Type III LAD Variations

Posterolateral branch variants

Although the original CASS investigators provided for 3 PL branches in their coronary model, we have limited the right dominant, left dominant and co-dominant basic PL configurations to two PL branches. The goal, in so doing, is to align the PL branch designations to the LV segment rows in the “17-segment model” (specifically inferior and Inferolateral). If more PL branches are desired, they can be accommodated within the branching variants described below. (For example, if three PL branches of equivalent size are seen, this can be simulated by selecting a two-branch option with subsequent selection of a ‘dual’ variant configuration for one of the two initial branches.)

(a) Single PL branch

Figure 9 indicates branch variations for size 1, 2 and 3 posterolateral branches. As indicated in the Tutorial on The Template Selection Process, it is assumed that a single branch in this region makes equivalent contributions to the inferior as well as the Inferolateral LV myocardial segments (a size 1 branch supplies the combined equivalent of one LV segment, a size 2 branch the equivalent of two segments and a size 3 branch supplies the majority of three segments).

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Figure 9 – PL variants by vessel size

(b) Two PL branches

The Posterolateral coronary artery configuration tabs (RD-PL, LD-PL and CoD-PL) portray PL branch combinations available for right, left and co-dominant arterial systems. When a two-branch option is selected, the rPL branch is assigned to the inferior LV segments while the lPL branch is assigned to the Inferolateral LV segments. The branch variants for rPL and lPL branches are similar in configuration to the variants shown in Figure 9.

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Obtuse Marginal Branches

The CASS reporting system also allowed for three branches in the obtuse marginal region. Similar to the posterolateral region, we reduced the branch number allowance to 2 in order to align with the 2 obtuse margin LV region rows , the anterolateral and inferolateral segments. (See heading below entitled Posterolateral and marginal arteries supply inferolateral LV segments. Two two distinct branch types supply the basal and mid inferolateral and apical lateral LV segments, the left posterolateral branch and the inferolateral marginal branch.)

(a) Anterolateral marginal

The size 1 AL variants shown in Figure 10 supply the basal anterolateral LV segment. The dual variant provides a means to convey the existence of more than 2 marginal branches, the extra branch contributing the ALM segments. A thin variant has been found useful (for many other branches as well) to convey the existence of a branch of significant length but a small diameter to rendering it unsuitable for intervention.

Figure 10 – AL Marginal Size 1 Variants

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The AL Marginal Size 3 variant list includes three unique branch configurations, termed transverse variants. The ALM normally follows a curvilinear path, initially parallel to the AV groove and finally following an axial course over the basal AL, mid AL and apical lateral LV segments. In a transverse variant, the ALM pathway has a final transverse rather than an axial direction terminating in the mid inferolateral segment.

(b) Inferolateral Marginal

Figure 13 – IL Marginal Size 1 Variants


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The nature of most variant configurations presented for all branches are self- evident, but two shaped deserve special discussion. The first is the double branch, a relatively common branch configuration that has three important and relatively equal terminating sub-branches. The final variant is the asymmetric variant with two important branches, but one that is clearly larger than then other. Somewhat arbitrarily, we have specified that the region supplied by this variant will be divided in a 2/3 – 1/3 proportion between the two branches. Also, the asymmetric variant can be converted into two branches of unequal size, if needed to describe a branch arrangement not provided for in the basic branch templates (see tutorial on vessel editing).

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Posterolateral and marginal arteries supply inferolateral LV segments

Two distinct coronary artery configurations can be associated with the basal and mid inferolateral LV segments (see Figure 16 below): (1) Inferolateral marginal branch that originates from the anterior AV groove circumflex and follows a curvilinear pathway before following the long axis of the LV; (2) Posterolateral branch with an almost perpendicular connection to the posterior AV groove portion of the RCA or circumflex. Figure 16 depicts a configuration in which a distal obtuse (inferolateral) marginal branch and a left posterolateral branch both supply the basal and inferior inferolateral LV segments. (Note the regions on the polar plot jeopardized by a severe mid circumflex lesion.)

Figure 16 – Dual IL Supply

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Ramus Intermedius (RI)

The ramus intermedius designation is associated with a unique pathway that is between a diagonal and a marginal in its distribution with less variability in its location. A Size 1 RI supplies the basal anterior segment, a Size 2 supplied the basal anterior and mid anterolateral segments and a Size 3 extends its distribution to the apical lateral segment.

Figure 17 – Ramus Intermedius Size 1 Variants


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Diagonal Branches

Most diagonal branches follow a predictable oblique pathway reflective of the orientation of the underlying superficial myocardial fibers. The diagonal branches are categorized according to their LV myocardial segment of origin – basal, mid or apical.

(a) Basal diagonal (variably called D1 or proximal diagonal)

Figure 20 – Basal (proximal) Diagonal Size 1 Variants

A size 1 branch supplies the majority of one LV segment. Because of the origin and trajectory of the basal diagonal, this arterial distribution is divided between the basal and mid anterior segments. A size 2 basal diagonal continues the size 1 pathway to supply all of the mid anterior and half of the mid anterolateral segments, a total of 2 LV segments. Finally, a size 3 basal diagonal continues the size 2 pathway to include most of the apical lateral LV segment.

As with other coronary branches, diagonal variants include proximal and distal branching, asymmetric branching, double branches, dual arteries and thin shapes. In addition two important variants in the usual oblique vessel pathway are seen. The first is the transverse variant that follows a divergent lateral pathway usually terminating in the mid anterolateral or inferolateral LV segment, depending upon branch size.The second unique variant is the axial configuration in which the direction of the branch runs parallel to the LAD and interventricular groove. This variant can be unbranched with flow to the anterior LV segments only or it may give discrete side branches the mid anterolateral or apical lateral segments or to both.

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(b) Mid diagonal

Figure 23 – Mid Diagonal Size 1 Variants

The mid diagonal has a size 1 distribution to the mid anterior LV segment, a size 2 distribution that extends to the apical anterior segment and a size 3 variety that continues laterally over the apical lateral LV segment. As with the larger basal diagonal, the mid diagonal can have transverse and axial variants as shown in Figure 24 and 25.


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(b) Distal (apical) diagonal

The configurations of distal diagonal variants are shown in Figures 26 and 27. The size 1 variant distribution is limited to the apical anterior segments and the less common size 2 branch extends this distribution area to the apical lateral LV segment.

Figure 26 – Distal (Apical) Diagonal Size 1 Variants

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Figure 27 – Distal (Apical) Diagonal Size 2 Variants

Other vessel segments with variant designations

(a) Mid LAD

‘Left clicking’ on the mid LAD segment also activates the secondary segment variant list. Two additional variant options are given, one with a muscle bridge and a second option with smaller calibre vessel.

(b) Apical LAD

In addition to the long Type III variants described in Figure 8, activation of the distal LAD variant list will reveal an apical muscle bridge variant as well as a variation with a prominent side branch to the apical lateral LV segment.

(c) Left main

Options are available for a short (<1 cm) or long (>2 cm) variant

(d) Conus artery

Options available include a large branch and a variant with a separate origin from the right coronary cusp.

(e) Mid AV groove circumflex

Activating the variant list for this segment allows adjustments to the vessel calibre and the addition of a prominent atrial branch.

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Key Points

• ‘Left-clicking’ on the segment or branch of interest activates the variant options list.

• The variant list cannot be accessed unless the Edit Mode box in the lower left corner of the CARAT window is blank. This can be achieved by ‘right clicking’ over any open area on the left (palate) side of the CARAT window.

• Avoid excessive use of branch and segment variants. Their value is to capture clinically meaningful anatomic variations.

• Selection of dual variants and selecting and editing asymmetric branches provide opportunities to increase the number of branches not allowed with basic configurations. Again this capability should be reserved for situations where this level of detail is clinically important.

• The basic structure of CARAT prevents vessel overlap of vessel branches. However, when branch variants are activated, situations may arise where vessels overlap. When this happens the basic interpretation should be questioned and modification are necessary.

• Branch variants retain the same total distribution size as the original unbranched configuration. Myocardial values are divided amongst the sub- branches preserving the accuracy of jeopardy and area-at-risk calculations.

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Tutorial 8: Coronary Artery Total Occlusion

Total coronary artery occlusions can be seen in a variety of acute and chronic clinical settings; this tutorial outlines the data fields in CARAT that can provide relevant angiographic, functional and procedural detail for patients with chronic total occlusions.

Lesion entry:

While in the Lesion edit mode (check the lower left corner of the page), the first step in drawing a total occlusion is to trace a lesion, proximal to distal, and the severity is set at a default value of ‘50%’. The second step, as with all lesions, is to ‘right click’ the lesion revealing the sub-menu shown in Figure 1 asking that the appropriate lesion grade be selected. For our purpose, we will select ‘100%’.

Figure 1: Selecting Lesion Severity.

The ‘100%’ selection will automatically open the Total Occlusion menu shown in Figure 2 allowing the operator to enter key descriptive information. The first designation is Duration of the total occlusion, if known. Chronic total occlusion is usually defined as angiographic or clinical evidence of occlusion > 3 months or ‘Unknown’. When either of these choices is selected, the other data elements on the drop-down showing key features of the Total Occlusion are activated (turn from grey to black) as in Figure 3 allowing further data entry. The Duration field also allows one to specify if the totally occluded segment has been bypassed and, if so, is the surgical conduit compromised. (Prior Cardiac Surgery is included as a discrete item as a prior opening of the pericardium is believed to confer an element of safety in the event of procedure-related pericardial bleeding.)

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Figure 2: Total Occlusion Duration.

Figure 3 shows the Total Occlusion characteristics that can be documented: type of collaterals, lesion length, features of the proximal and distal cap, adjacent side branches and, importantly, whether there is evidence of prior infarction or regional wall motion abnormality in the region supplied by the total occlusion.

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Figure 3: Chronic Total Occlusion Detail.

Collaterals:

Description of collaterals and TIMI flow are important to total occlusion assessment. When Collaterals is selected from the menu, tracing their pathway, from donor vessel to recipient, will record these important connections. When drawn, right-clicking on the collateral will activate a collateral drop-down menu which allows you to highlight important collaterals and enter collateral detail, as in Figure 4 below. The Origin and Termination of a collateral is recorded automatically with an opportunity to distinguish between epicardial and trans-septal pathways, single or multiple and whether the collateral is believed to be suitable for retrograde wiring if intervention is being considered. Two commonly used collateral classification systems (Rentrop and Werner) can be specified as well.

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Figure 4: Collateral Properties.

Selecting TIMI Flow from the main menu and specifying the nature and location of each flow grade change should be undertaken at this point as well.

Intervention Detail:

If PCI is attempted, the menu specifying Interventional Detail can be accessed in one of two ways depending on whether or not a stent is deployed. With no stent deployment, Lesion edit mode is selected from the main menu, the total occlusion is right-clicked and Interventional Detail is selected and the requested information is entered. Where a balloon is inflated without a stent being subsequently used, a “B” designation is left on the lesion in question to indicate that a POBA was performed (no stent).

If a stent is deployed the device menu is selected differently: first the stent is right-clicked while the stent is still shaded in pink (active state) and Interventional Detail is then selected. The lesion or stent origin and termination points are automatically specified along with initial and final LDR.

At this point three separate tabs are available when either pathway. The first (Figure 5 below) asks for

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information on the access point(s) and sheath French size.

Figure 5: Interventional Detail: Access.

The third tab identifies specific procedural strategies, unique to CTO intervention, that were used (Figure 6).

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Figure 6: Interventional Detail: Strategies.

Finally, the Device detail tab is selected allowing a comprehensive sequential display of all devices used, including deployment detail (Figure 7). The deploy date will default to the date of the current procedure; however if there is a need to document previously deployed stents, the deploy date field is adjustable and is available for this purpose.

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Figure 7: Intervention Detail: Devices.

At this point all devices used can be documented sequentially. Initially Add is selected and the Device Type is chosen from the drop-down list in Figure 8. In this example, the operator wished to document that a Pilot 200 wire was used. Then the Device Model field is selected providing a fairly comprehensive list of currently available wires (Figure 9). (In most PCI procedures there is little value in documenting wire usage. However wire choices can be documented for future reference when this information may be of future use.)

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Figure 8: Intervention Detail: Device Type.

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Figure 9: Procedural Detail: Device Model - Wires.

(Although sequential device use descriptions for more complex re-entry and retrograde strategies are possible, a simple antegrade procedure is used in this example.)

The Add button is now again activated and Balloon is selected revealing the range of balloons currently available (Figure 10). A SPRINTER Legend balloon was chosen and the fields that follow allowed documentation of the balloon diameter, length and maximum inflation pressure used.

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Figure 10: Procedural Detail: Device Model - Balloon.

At this point Add can be activated yet again to reveal Stent options with the ability to specify size and inflation detail (Figure 11).

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Figure 11: Procedural Detail: Device Model - Stent.

For illustration purposes, we will assume that a high-pressure balloon was used for post-stent dilatation using a Voyager NC balloon and, finally, the procedure was assessed finally using IVUS. The final tabulation of all devices used, their order and size/deployment detail is documented in the tables on the upper left portion of the page as shown in Figure 12. (If other equipment such as atherectomy, thrombectomy, OCT, FFR assessment or even IABP or support devices were used in the procedure, this activity could be included in this tabulation as well, and in proper sequence.)

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Figure 12: Final Device tabulation.

Key Points:

• Lesion related detail is requested only when a total occlusion is chronic by current definitions.

• When a balloon is used without a stent, the Intervention Detail menu that should be used is accessed by first right-clicking the lesion in question while in the Lesion edit mode (shown on lower left corner of working page) and then selecting Intervention Detail.

• When a stent is used, access the Intervention Detail menu by right-clicking the stent in question and then selecting Intervention Detail while the Stent edit mode is active (obvious because the stent appears in pink while in this state).

• If a patient returns for an angiogram at a later time, the device information is carried forward, but only the stent detail is shown in the summary device table in the upper left corner.

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Coronary Scoring Systems: A Historical Perspective

Merril Knudtson, MD

Background

The coronary artery reporting system adopted by APPROACH © between 1995 and 2008 was based upon the graphic tool known as Heartview © with modifications from the literature to increase the tool’s precision.

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A new graphic coronary anatomy and intervention reporting tool called CARAT © (Coronary Artery Reporting and Archiving Tool) has been developed for use by APPROACH to achieve, inter alia, the following anatomical reporting goals:

1. To capture greater patient-level detail2. To develop a clinically relevant expression of lesion severity3. To present a credible expression of the size and location of the myocardial bed supplied by diseased

arteries4. To abandon the historic three-region (anterolateral, lateral and posterolateral) LV model in favour of

the 17-segment model currently adopted by most cardiac imaging systems.2

This document summarizes observations from literature reports that influenced the design of CARAT © with summary comments concerning how this information was used.

Classifying Lesion Severity – What’s in a number?

Although attempts have been made to create more complicated and ‘granular’ lesion severity grading systems, none of these have improved upon the early lesion severity categorization of Oberman et al (1972)3. These clinically important severity ranges are explained below (see also Figure below):

• <50% diameter reduction. Lesions in this range are very unlikely to have hemodynamic and clinical significance based upon severity alone and further severity subdivisions within this range have no proven value.

• >50% and <70% diameter reduction. Lesions in this range are of borderline hemodynamic and clinical significance but 35% were found to have a compromised hyperemic response in one large series4. This is an important range to capture from a clinical perspective for interventions on lesions in this range would benefit from confirmation of their hemodynamic significance by prior non-invasive testing or by FFR assessment at the time of angiography.

• >70% but <100%. Almost all lesions in this range are hemodynamically significant, thus seeking supplementary confirmation of hemodynamic significance is not warranted in most cases. Further there is no established benefit to assigning a more precise stenosis grade within this range. Gould5-7 has shown that the hyperemic response falls off geometrically in the 65-85% diameter reduction range, a range that Gensini refers to as “the resistance elbow”. In this range, angiography simply lacks adequate discriminating power. Lesions >85% may demonstrate reduced flow at rest, the apparent justification for the addition of a “90-99%” category by some investigators8-11, but it is not clear whether this category is clinically useful.

• 100%. A separate category for completely occluded vessels is warranted for multiple clinical and therapeutic reasons.

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0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100

Luminal Diameter Reduction (%)

If a single threshold for clinical significance were adopted, the literature is divided on whether this threshold should be 50% 3, 8, 12-14 or 75%1, 9, 15, 16. Clearly the 70% cutoff has the greatest physiologic support 7, 15 and has been labeled the “gold standard” threshold for clinical significance7.

Rather than accepting a fixed threshold for significance, several investigators have assigned a lesion score that is graded by lesion severity 13, 16-19. This graded value is then used alone, or used as a multiplier along with some expression of myocardial territory at risk, with the belief that a graded valuation and/or a combined score is a more sensitive and reliable outcome predictor than a binary designation of significance.

The 7 published lesion-weighting systems are listed below with the score shown in bold print beside the severity ranges used:

• 1 = <50%; 2= 50-90% single lesion; 3=50-90% multiple lesions; 4=90%; 5=100% 20• 1=Trivial; 2=<50%; 3=50-75%; 4=75-90%; 5=100% 3• 1=<50%; 2=50-75%; 3=75-99%; 4=100% 17, 19, 21, 22• 0.2=<50%; 0.4=50-75%; 0.6=75-90%; 0.8=90-99%; 1.0=100% 16• 1=70-90%; 3=90-99%; 5=100% 18• 1=25-50%; 2=50-75%; 4=75-90%; 8=90-99%; 16=100% 10• 0=<50%; 2=50-99%; 5=100% 13

The lesion range weighting scores above lack appropriate validation and face validity. For example, it is not clear why a 100% occlusion, usually associated with collateral support and frequently associated with an area of prior infarction, should be given a consistently higher weighting than more vulnerable lesions in the 70-90% range. APPROACH has not adopted a weighting system based upon diameter severity and will employ the single threshold stenosis value of 75% (50% for LM).

As 50%, 70% and 100% luminal diameter obstruction thresholds have clinical utility and a strong evidence base, is there clinical value in including other intermediate severity levels in a clinical scoring system? It has been shown that simple visual estimates of severity, particularly in more severe lesions, have a stronger correlation with baseline exercise test performance than automated quantitative techniques 23. One may conclude from this that there be value in providing 60, 80 and 90% options to angiographers in order to allow expression of their clinically integrated impressions of lesion severity. A “60%” designation, for example, may be selected as a cautionary statement of borderline severity. There is no value in attempting to sub-classify lesion severity in the <50% range; a simple statement of the existence of angiographically identifiable disease should suffice19. Also, a strategy of intervening on lesions <50% has been discredited24.

>70%

<50%

50-70%

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Myocardial Jeopardy – A critical dimension

From the earliest days of angiography, estimations of the amount of myocardium supplied by diseased coronary vessels and the impact of these estimates on treatment and outcome have received close study20,

25 Initially these estimates were based upon a simple statement of the number of diseased major epicardial vessels8, but the lack of precision of this approach soon became evident and adjustments were made for the dominant influence of proximal LAD and LM disease8, 26. In the later part of the 1970’s standardized myocardial templates were developed and used in natural history studies, but the wide anatomic variability seen between individual patients in clinical practice pointed to the obvious deficiencies in these over simplified models.

Unfortunately precise measurement of the relative amounts of LV myocardium supplied by each major epicardial artery is available from a single pathologic study, that of Kalbfleisch and Hort (1977)27.

The following table indicates the percentage of the LV volume assigned to each major epicardial artery in five classic clinical studies as well as the landmark pathology measurements of Kalbfleisch and Hort. The variable size of LCx and RCA distributions in these studies is not surprising due to the wide variability in the source of blood supply the posterolateral LV free wall.

LAD LCx RCA

Alderman et al (1992)12 48 28 24Gensini (1975)17 42 42 16Brandt (1977)16 47 40 13Jenkins (1978)21 43 29 28Dash (1977)14 50 33 17Kalbfleisch & Hort (1977)27 49-53 18-27 18-33

The table below indicates the percentage of the LV volume attributed to the septum as well as the anterior, lateral and posterolateral free wall territories in three clinical models along with the pathological work of Kalbfleisch and Hort.

Anterior Lateral Inferolateral Septum

Brandt (1977)16 13 20 20 47Dash (1977)14 17 17 17 49Graham (2006)1 20 19 19 42Fulton (1952)28 - - - 31Lorenz (1999)29 - - - 34Kalbfleisch & Hort (1977)27

27-32 18-27 9-22 34 (2/3 LAD)Assumed

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Challenges in quantifying septal coronary flow

Recent imaging studies are consistent with pathologic studies over the last 80 years that the septum accounts for 31-34% of the LV mass28, 30, 31. Unfortunately, it is equally clear that the relative contribution of LAD and PDA septal perforators to septal blood flow is highly variable and remains difficult to measure or estimate due to their large number and variable size and location. Based upon an autopsy series of 31 patients, James et al (1958) reported that the LAD provided 60-70% of septum in 23% of patients, 70-80% of patients in 29% and 80-90% of patients in 48%.32 (Although this report did not give individual anatomic detail, one would suspect that the third group included patients with a Type 3 LAD or a ‘septal arcade’ variant.) A Canadian autopsy series of 12 human hearts reported that the LAD supplied 50% of the septum in half of the specimens and 2/3 of the septum in the remaining half.33 The review of Smith (1962) stated that the LAD contribution to septal blood flow was two-thirds30, and this estimate continues to receive wide support.

Assigning relative contributions of LAD and PDA perforator flow to this substantial and functionally important part of the LV myocardium remains a challenge. Alderman et al (1992) in the angiographic methods used by the BARI study assigned 3 of the 5 septal points (60%) to the LAD, 2 of these points to the largest perforator.12

Toward an optimal myocardium-focused coronary reporting tool

The reporting strategies summarized in this document have had modest value in evaluating group behavior in clinical trails and epidemiologic investigations, but they all lack precision and have significant shortcomings in capturing individual patient variability.

The following features are desirable in a reporting tool:

1. Variability in the number, size and location of LV free wall branches should be provided for with dynamic adjustment of the amount and regional location of myocardium assigned to each1, 12, 16.

2. Allow for variation in length of distal LAD (Types 1-3)1.3. Characterize the geometry and size of LV segments in the 17-segment model. Currently jeopardy

calculations in CARAT assume a size of 6% for each segment. This value could be easily substituted for by actual CMR measurements in normal hearts, when they are available.

4. Capture the variations in RCA and LCx supply of posterolateral LV.5. Allow for anomalous coronary origins and pathways.6. Capture the variable contribution of anterior septals from LAD (variation from 50 – 90%) and inferior

septals from PDA (variation from 10 to 33%) to the interventricular septum. There is no literature that would help in making this decision.

Diffuseness of Coronary Disease – Is it measurable?

Although pathologic studies have consistently shown a strong correlation between the endothelial extent of atherosclerosis and the severity of lipid disorders and other risk factors19, 34, attempts to develop clinically useful measures of diffuseness of atherosclerosis continue to be disappointing10.

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Literature Summary

• Parker et al (1966) – Kingston, Ontario 25

• Purpose – Correlate angiographic severity with prior MI, symptoms and resting ECG changes• Coronary Score

» Lesion Grade (Variable)• Grade 1 - <50% area stenosis; • Grade 2 - >50% area stenosis but <100%; • Grade 3 – 100%

» LV Extent• Number of major vessels with > Grade 2 lesions

• Conclusions » 100% occlusion correlated with prior MI » Presence of symptoms and resting ECG changes correlated with severe multi-vessel disease » No correlation of variable lesion grade with outcome » Historical importance – this Canadian centre was the first to report association of CAD extent and clinical status

• Friesinger et al (1970) – Vanderbilt 20

• Purpose – Establish a coronary scoring system that will permit anatomy correlation with outcome• Coronary Score

» Lesion Grade (Variable)• 0 – no disease; • 1 – lesions <50% area stenosis; • 2 – single lesion >50% but <90%; • 3 – multiple lesions >50% but <90%; • 4 – 90%; • 5 – 100%.

» LV Extent• Three regions: LAD, LCx and RCA

» Score calculation • Friesinger Score - Sum of most severe lesion grade 1 to 5) for each of 3 regions• Maximum score total is 15.

• Conclusions » The coronary score was a stronger predictor of mortality than all measured clinical factors » Manuscript does not validate lesion grading system used

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• Oberman et al (1972) – Birmingham 3

• Purpose – Establish correlation between lesion severity and subsequent mortality• Coronary Score

» Lesion Grade (Variable)• 1 – trivial disease; • 2 – lesions < 50% diameter reduction; • 3 – 50 – 75%; • 4 – 75 – 90%; • 5 – 100%

» LV Extent• LAD, RCA and LCX divided into proximal and distal segments and graded separately. LM

treated as 1 segment. Total segments possible – 7. • Number of diseased vessels

» • Score calculation• Oberman Score - Sum of lesion grade for each of the 7 individual segments. (A LM lesion is

given the sum of scores for LAD plus LCx.) • Maximum score is 35• Number of diseased major vessels with diameter stenosis >50% (0-3)

• Conclusions » Confirms correlation of 2 and 3-vessel disease with mortality, but minor effect with 1 vessel disease.

» There was a mortality multiplying effect if CHF present. » Of note, the Oberman Score described above was not used in the analysis, only the number of diseased vessels.

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• Bruschke et al (1973) – Cleveland 8 • Purpose – Correlate mortality over 4 years with number of diseased vessels in patients not treated with CABG

• Coronary Score » Lesion Grade (Fixed)

• Diameter reduction >50% defines significant disease• Grading system: normal, <30%, 30-50%, 50-90%, >90% and 100%

» LV Extent• Number of major vessels (0-3)

• Conclusions » Mortality increases with number of diseased vessels. » Single vessel disease mortality not significantly influenced by lesions <50% in other vessels.

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• Brymer et al (1974) – Ann Arbor, Michigan 26 • Purpose – Correlate coronary anatomy with outcome• Coronary Score

» See Friesinger Score » Also - number of diseased vessels (>50% area reduction) with and without LAD involvement

• Conclusions » Significant influence of proximal LAD disease on mortality when added to number of diseased vessels or to Friesinger score.

• Gould et al (1974, 1974 and 2009) - Houston 5-7

• Purpose – Animal work correlating diameter stenosis to reduction in flow• Conclusions

» 50-85% diameter stenosis defines threshold for clinical significance (Hyperemic response starts to diminish >50% ldr with resting flow reduced when ldr is >85%)

» Propose >70% as the “gold standard” for defining a single significant clinical endpoint » 65-95% diameter stenosis needed to see impaired flow, but angiographic measurement limitations do not allow finer discrimination within this range

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• Gensini G.G. (1975) – Syracuse 17

• Purpose – Description of a Coronary Artery Disease Scoring and Retrieval System (Cardscores). The system was intended to take into account: (1) Geometrically increasing severity of lesions – 25, 50, 75, 90, 99 and 100% diameter reduction; (2) cumulative effect of multiple lesions; (3) lesion location; (4) influence of collaterals; (b) vessel graftability.

• Coronary Score – » Severity score – With each step in the 25 – 50 – 75 – 90 – 99 – 100% diameter reduction progression, the impact on flow doubles in accordance with Poiseuille’s law. As a result severity scores for lesions in this progression were assigned the values 1 – 2 – 4 – 8 – 16 – 32.

» Region multiplying factors for coronary segments were designated to express the relative amount of myocardium supplied by a diseased segment (see diagram)

» Collateral factor – The severity score adjustment for collaterals is indicated on the right side of the table below. The adjustment is reduced by the extent of disease in the vessel that is the source of collaterals (left column).

» Gensini Score Calculation: severity score X the segment location multiplying factor X Collateral adjustment factor

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• Brandt et al (1977) – Auckland, NZ16

• Purpose – Propose a flexible myocardial reporting and scoring model• Scoring System

» Grade of Stenosis severity (x-sectional area)• 100 % - Correction value = 1.0• 90-99% - Correction value = 0.8• 75-90% - Correction value = 0.6• 50-75% - Correction value = 0.4• <50% - Correction value = 0.2

» Myocardial Value• The Green Lane Model was loosely based upon the definitions of WG Austen et al 35 and

the 15 point scoring system of GC Friesinger et al 20, modified by a 5-region diagram used by Auckland radiologists to diagram coronary anatomy. The regions are LAD septum, PDA septum, diagonal region, marginal region and posterolateral region and the percentage of LV myocardium assigned to each region is listed below:

» LAD septum -30% (Value – 5) » PDA septum -17% (Value – 2) » Diagonals -13% (Value – 2) » Marginals -20% (Value – 3) » Posterolaterals -20% (Value – 3)

• The angiographer draws the location of LV free wall branches on a template of the above 5 regions and the percentage area of each region supplied by each diseased vessel is estimate visually (see diagram below).

» Myocardial Score - The myocardial value of each diseased artery is multiplied by the Stenosis Severity Correction value and is then summed to obtain the Myocardial Score. This is an expression of the combined influence of jeopardized myocadial area and stenosis severity.

» The LV myocardium percentages specified above are similar to Kalbfleish and Hort (1977) and Dash (1977), but perhaps undervalue the PDA and overvalue the circumflex contributions.

• Conclusions » Rationale for specified stenosis grading not given in paper » An elegant but operator dependent scoring system

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• Kalbfleisch and Hort – 1977 - Marburg an der Lahn, Germany 27

This is an elegant and landmark pathologic study of the amount of myocardium supplied by the left anterior descending, circumflex and right coronary arteries in 171 human hearts. The hearts were categorized by “vascular type”: “left coronary type” with LCA supplying all of LV (left dominant system); “RCA type” with RCA supplying only the posterior-septal wall (co-dominant system); and three “normal” types in which the RCA and LCx both supply variable portions of the posterior wall (right dominant systems). Based upon this data, the following regional LV mass calculations can be reasoned for the five Green Lane regions. The LAD-PDA septum division was calculated using the Green Lane 64:36 split of LAD and PDA blood supply to the septum.

• LAD (Anterior septum and adjacent Ant. Wall) -32%• PDA (Inferior septum and adjacent PL wall) -18%• Diagonals -15% • Marginals -18%• Posterolaterals -17%

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• Dash et al (1977) – Harvard 14

• Purpose » Coronary anatomy - LV function correlation » Does the development and extent of ischemic cardiomyopathy correlate with coronary anatomy?

• Coronary Score » Lesion Grade (Fixed)

• Primary threshold level - “Significant” defined as Area reduction >70% » LV Extent

• Two points are assigned to each of 6 specified segments with a significant proximal stenosis (see diagram below). The territory assignments are clear except dLAD (1) is unspecified but is likely a combination of anterior wall and septum.

• Conclusions » An angiographic scoring system grade based upon myocardial volume at risk is a better predictor of ischemic cardiomyopathy development than a 1, 2 or 3 vessel disease classification.

» Paper does not specify the basis for the jeopardy scoring system but is very similar to Kalbfleisch and Hort (1977)

• Proudfit et al (1978) – Cleveland 11

• Purpose - Explore association of clinical and angiographic variables with 5-9 year survival in a cohort of 600 non-surgical patients.

• Coronary Score » Lesion grade - diameter reduction

• < 30% • 30-50%• 50-90% - Primary threshold level• Subtotal• 100%

• Conclusions » Mortality increases with the number of vessels with diameter lesions > 50% » In patients with 2 and 3 vessel disease who are referred for surgery, complete revascularization is associated with a better survival than patients incompletely revascularized

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• Jenkins et al (1978) – Victoria, Australia 21

• Purpose - Correlate serum cholesterol with angiographic extent of disease• Coronary Score

» Lesion Grade• 1 – <50% luminal diameter reduction• 2 – 50-75%• 3 – 75-99%• 4 – 100%

» LV Extent – 8 proximal coronary segments analyzed » Gensini score – sum of lesion grade for each of 8 segments

• Conclusions » Serum lipids correlate with extent of coronary disease

• Harris et al (1980) – Duke 9

• Purpose - To determine the incremental influence of 50% lesions on survival in 1183 medically treated patients with 1, 2 or 3 vessels (lesions greater than 75% luminal diameter reduction)

• Coronary Score » Lesion grade - diameter reduction

• <25% • 25%• 50% - Secondary threshold level• 75% - Primary threshold level• 90%• 100%

• Conclusions » The presence of one or more lesions of 50% severity was not associated with an increased mortality in patients with 1, 2 or 3 vessels with 75% lesions.

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• Lee et al – 1981 - Duke 36

• Purpose –Study of 18 autopsy human hearts confirming the correlation of relative infarction size and vessel distribution area.

• Results » The ischemic bed sizes by major coronary region were:

• Circumflex -30% (varied from 21% to 43%)• RCA -32% (varied from 24% to 37%)• LAD -44% (varied from 29% to 66%)

• Conclusions » Although this is a small study that does not provide enough detail to arrive at a 5-region breakdown of myocardial mass, the study presents an important confirmation that infarct size correlates closely with the regional LV mass.

• Leaman et al (1981) – Rotterdam 18

• Purpose » To fashion a coronary scoring system that takes into account lesion severity and distribution area.

» To evaluate the score as a means to predict symptoms and LV function• Coronary Score

» Lesion grade – diameter reduction• 70-90%• 90-99%• 100%

» LV Weighing Factor – see diagram – after Gensini (1975) » Leaman Score Calculation - Multiply lesion score by weighting factor for each segment

• Conclusions » Symptoms and LV function do not correlate with this score. » No supporting comments on the validity of magnifying the LV weighting factor by the lesion severity.

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• White et al (1984) – Iowa City37

• Purpose – Does lesion angiographic severity predict maximum hyperemic response• Methodology

» Correlate caliper-assistant diameter measurements with hyperemic flow Doppler measurements• Conclusions

» Poor correlation between angiographic lesion severity and physiologic maximal hyperemic response as measured by flow Doppler

• Reardon et al (1985) – Victoria, Australia 19

• Purpose - Correlate lipid concentrations with coronary severity• Coronary Score – Gensini score (See Jenkins et al (1978)

» Lesion grade• 1 – <50% luminal diameter reduction• 2 – 50-75%• 3 – 75-99%• 4 – 100%

» LV Extent – 8 Segment method • Conclusion

» 22% of the variation in coronary severity can be accounted for by lipid concentrations

• Califf et al (1985) – Duke 38

• Purpose » Prognostic value of Jeopardy score » Incremental value of score over coding number of diseased arteries

• Coronary Score » Lesion grade

• Diameter stenosis >75% considered significant (rather than >50% used in work of Harris et al (1978)

» LV Extent• Uses the Dash et al (1977) 6-segment grading system

» Score Calculation• Conclusions

» Jeopardy score is an improvement over classifying CAD severity on basis of number of diseased arteries

» Further refinement needed, in particular paying more attention to pLAD disease and other anatomic factors

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• Hamsten et al (1986) – Stockholm, Sweden 10

• Purpose » Correlate lipoprotein risk factors with angiographic score » Score designed to capture disease diffuseness/extent

• Coronary Score » Segments – 15 proximal segments (AHA) » Diffuseness score – Hamsten Score

• Multiply “Extension” by “Mean plaque size” score (maximum – 9) for each of 15 segments » Stenosis score (Modified Gensini score)

• 0 – <25% luminal diameter reduction• 1 – 25-50%• 2 – 50-75%• 4 – 75-90%• 8 – 90-99%• 16 – 100%

» Jenkins et al (1978) Score• Conclusion

» Poor correlation between extent of lipid disorder and coronary severity and diffuseness measures

• Sulllivan et al (1990) – Sydney, Australia 22

• Purpose » Correlate lipoprotein risk factors with angiographic score » Score designed to reflect the amount of endothelial surface area involved with atheroma

• Coronary Score » Vessel score – number of vessels with stenosis >70% luminal diameter reduction » Stenosis score

• 1 – <50% luminal diameter reduction• 2 – 50-75%• 3 – 75-99%• 4 – 100%

» Gensini Score – Sum the severity score above for each of the 8 segments (maximum score: 32) » “Extent score” – Novel score in this study. The following is a list of hypothesized percent distribution of coronary artery endothelial surface area:• LM – 5%• LAD – 20%• Main diagonal – 10%• Septal perforator – 5%• Left circumflex – 20%• OM and PL vessels – 10%• RCA – 20%• PDA – 10%

• Conclusions » Age and lipid profile correlates with the “Extent Score

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• Alderman et al (1992) – Stanford 12

• Purpose » Describe definitions used by the BARI Trial

• LV free wall branch sizes• Coronary Score

» Lesion grade• Significant if diameter reduction is >50%

» BARI coronary map » BARI “Myocardial Territory Units” » Score Calculation

• “Lesion jeopardy unit score” divided by the “Global left ventricular territory unit score”• Conclusions

» Advantages: flexibility in branch sizing and numbers and adjusting for coronary dominance » Jeopardy expressed as % of total LV » Problems:

• No value assignment to inferoseptal area • PDA relative size appears to be too small at 8% • Excessive points given to branched side branches

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• Seller et al (1993) - Houston39

• Purpose - Establish mathematical relationship between epicardial vessel length and amount of myocardium supplied

• Method » Radiolabelled microsphere injection into in vivo and PM hearts with measurement of LV mass and summed epicardial 1st, 2nd and 3rd generation coronary branch length

• Conclusions » Summed length of epicardial vessel length is closely and linearly related to the size of the myocardial bed

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• Sianos et al (2005) – Rotterdam13

• Purpose - Create a single numerical score that captures CAD complexity (including the number and location of lesions)

• Coronary Score » Lesion grade – Segment modifiers

• <50% - 0• 50-99% - score 2• 100% - score 5

» LV Extent –16 segments as per ARTS modification of AHA• Segment Weighting Factors (Leamon et al (1981)

» PDA – 1 » PL – 0.5 » LM – 5 » Proximal, Mid and apical LAD – 3.5 / 2.5 / 1 » D1 and D2 – 1 / 0.5 » RI – 1 » OM and Distal LCx – 1 / 0.5

» Adverse Features Score » Score Calculation – Summation of lesion and adverse feature scores for each of 16 segments

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• Graham et al (2006) – Alberta 1

• Purpose » Correlate APPROACH Jeopardy score with mortality in patients subsequently treated with CABG, PCI or no intervention in first year

» Compare APPROACH Jeopardy score with those of Dash et al (1977) and Alderman et al (1992)• Coronary Score

» Lesion grade – significance threshold• >70% diameter reduction, but >50% for LM lesions

» LV Extent• Named free-wall branches: small = 1; medium=2; large = 3.• Myocardial territories (and relative sizes) specified as per the diagram below. Small-unnamed

diagonal branches supply the “LAD Anterolateral Region” and similar small branches of the PDA supply the “PDA Posterolateral Region”.

» Score Calculation (APPROACH Jeopardy Score)• For free-wall LV branches: 44 X Diseased Branch size/summed score of all branches• For LAD: 33 for proximal LAD lesion; 22 for mid LAD and 11 for distal LAD, plus a portion of

the apical value of 5 depending upon the LAD type.• For the PDA: 18 for a proximal PDA lesion, 12 for mid lesion and 6 for distal lesion PLUS 5

for the apex with a Type 1 small LAD. • Conclusions

» Log mortality odds by treatment group for each Scoring system. PCI risk lower than Medical group. Surgery mortality, higher than PCI for lower Jeopardy Scores and lower than PCI and Medical for higher Scores

» APPROACH C-statistic highest, but not by much

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• Torino et al (2009)15 and (2010)4 – FAME Study• Purpose

» Assess physiologic importance as a function of diameter stenosis » Randomized trial of FFR-guided versus angiographic-guided PCI (FAME)

• Coronary Score » Lesion grade

• Lesions < 50% diameter excluded• 50 – 70% diameter reduction• >70% diameter reduction

• Conclusions » FFR < 0.8 in 35% of 50-70% lesions and 82% of >70% lesions » FFR-guided intervention – better event-free survival

™

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References

1. Graham MM, Faris PD, Ghali WA, Galbraith PD, Norris CM, Badry JT, Mitchell LB, Curtis MJ, Knudtson ML, Investigators A. Validation of three myocardial jeopardy scores in a population-based cardiac catheterization cohort. Am Heart J. 2006;142:254-2612. Cerqueira MD, Weissman NJ, Dilsizian V, Jacobs AK, Kaul S, Laskey WK, Pennell DJ, Rumberger JA, Ryan T, Verani MS. Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart: A statement for healthcare professionals from the cardiac imaging committee of the council on clinical cardiology of the american heart association. Circulation. 2002;105:539-5423. Oberman A, Jones WB, Riley CP, Reeves TJ, Sheffield LT, Turner ME. Natural history of coronary artery disease. BullNY Acad Med. 1972;48:1109-11254. Tonino PAL, Fearon WF, De Bruyne B, Oldroyd KG, Leesar MA, Ver Lee PN, MacCarthy PA, van’t Veer M, Pijls NHJ. Angiographic versus functional severity of coronary artery stenoses in the fame study: Fractional flow reserve versus angiography in multivessel evaluation. J Am Coll Cardiol. 2010;55:2816-28215. Gould KL, Lipscomb K, Hamilton GW. Physiologic basis for assessing critical coronary stenosis: Instantaneous flow response and regional distribution during coronary hyperemia as measures of coronary flow reserve. The American Journal of Cardiology. 1974;33:87-946. Gould KL, Lipscomb K. Effects of coronary stenoses on coronary flow reserve and resistance. The American Journal of Cardiology. 1974;34:48-557. Gould KL. Does coronary flow trump coronary anatomy? J Am Coll Cardiol Img. 2009;2:1009-10238. Bruschke AVgMD, Proudfit WLMD, Sones FMJMD. Progress study of 590 consecutive nonsurgical cases of coronary disease followed 5-9 years: I. Arterographic correlations. Circulation. 1973;47:1147-11539. Harris PJMDP, Behar VSMD, Conley MJMD, Harrell FEJPD, Lee KLPD, Peter RHMD, Kong YMD, Rosati RAMD. The prognostic significance of 50% coronary stenosis in medically treated patients with coronary artery disease. Circulation. 1980;62:240-24810. Hamsten A, Waldius G, Szamosi A, Dahlen A, De Faire U. Relationship of angiographically defined coronary artery disease to serum lipoproteins and apolipoproteins in young survivors of myocardial infarction. Circulation. 1986;73:1097-110911. Proudfit WL, Bruschke AVG, Sones Jr FM. Natural history of obstructive coronary artery disease: Ten-year study of 601 nonsurgical cases. Progress in Cardiovascular Diseases. 1978;21:53-7812. Alderman EL, Stadius M. The angiographic definitions of the bypass angioplasty revascujlarization investigation. Coronary Artery Disease. 1992;3:1189-120713. Sianos G, Morel M-A, Kappetein AP, Morice M-C, Colombo A, Dawkins KD, van den Brand M, Van Dyck N, Russell ME, Mohr FW, Serruys P. The syntax score: An angiographic tool grading the complexity of coronary artery disease. EuroInterv. 2005;1:219-22714. Dash H, Johnson RA, Dinsmore RE, Harthorne JW. Cardiomyopathic syndrome due to coronary artery disease. I: Relation to angiographic extent of coronary disease and to remote myocardial infarction. British Heart Journal. 1977;39:733-73915. Tonino PAL, De Bruyne B, Pijls NHJ, Siebert U, Ikeno F, van `t Veer M, Klauss V, Manoharan G, Engstrøm T, Oldroyd KG, Ver Lee PN, MacCarthy PA, Fearon WF. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. New England Journal of Medicine. 2009;360:213-22416. Brandt PWT, Partridge JB, Wattie WJ. Coronary arteriography: Method of presentation of the arteriogram report and a scoring system. Clin Radiol. 1977;28:361-36517. Gensini GGMD. The coronary artery disease scoring and retrrieval system. In: Gensini GGMD, ed. Coronary arteriography. Mount Kisco, New York: Futura Publishing Co.; 1975:271-274.18. Leaman D, Brower R, Meester G, Serruys P, van den Brand M. Coronary artery atherosclerosis: Severity of the disease, severity of angina pectoris and compromised left ventricular function. Circulation. 1981;63:285-29919. Reardon MFPD, Nestel PJMD, Craig IHMD, Harper RWMD. Lipoprotein predictors of the severity of coronary artery disease in men and women. Circulation. 1985;71:881-88820. Friesinger GC, Page EE, Ross RS. Prognostic significance of coronary arteriography. Transactions of the Association of American Physicians. 1970;83:78-9221. Jenkins PJ, Harper RW, Nestel PJ. Severity of coronary atherosclerosis related to lipoprotein concentration. BMJ. 1978;2:388-391

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22. Sullivan DR, Marwick TH, Freedman SB. A new method of scoring coronary angiograms to reflect extent of coronary atherosclerosis and improve correlation with major risk factors. American Heart Journal. 1990;119:1262-126723. Folland ED, Vogel RA, Hartigan P, Bates ER, Beauman GJ, Fortin T, Boucher C, Parisi AF. Relation between coronary artery stenosis assessed by visual, caliper, and computer methods and exercise capacity in patients with single- vessel coronary artery disease. The veterans affairs acme investigators. Circulation. 1994;89:2005-201424. Pijls NHJ, van Schaardenburgh P, Manoharan G, Boersma E, Bech J-W, van’t Veer M, Bär F, Hoorntje J, Koolen J, Wijns W, de Bruyne B. Percutaneous coronary intervention of functionally nonsignificant stenosis: 5-year follow-up of the defer study. Journal of the American College of Cardiology. 2007;49:2105-211125. Parker JO, DiGiorgi S, West RO. Selective coronary arteriography. Arteriographic patterns in coronary heart disease. Can Med Assoc J. 1966;95:291-29426. Brymer JF, Buter TH, Walton Jr JA, Willis Iii PW. A natural history study of the prognostic role of coronary arteriography. American Heart Journal. 1974;88:139-14327. Kalbfleisch H, Hort W. Quantitative study on the size of coronary artery supplying areas postmortem. Am Heart J. 1977;94:183-18828. Fulton RM, Hutchinson EC, Jones AM. Ventricular weight in cardiac hypertrophy. Br Heart J. 1952;14:413-42029. Lorenz CH, Walker ES, Morgan VL, Klein SS, Graham TP. Normal human right and left ventricular mass, systolic function, and gender differences by cine magnetic resonance imaging. Journal of Cardiovascular Magnetic Resonance. 1999;1:7-2130. Smith GT. The anatomy of the coronary circulation. Am J Cardiol. 1962;9:327-34231. Erich W, de la Chapelle C, Cohn AE. Anatomical ontogeny. B. Man. 1. A study of the coronary arteries. Am J Anat. 1931;49:241-28232. James TN, Burch GE. Blood supply of the human interventricular septum. Circulation. 1958;17:391-39633. Bertho E, Gagnon G. A comparative study in three dimension of the blood supply of the normal interventricular septum in human, canine, bovine, porcine, ovine and equine heart. Chest. 1964;46:251-26234. Solberg L, Strong J. Risk factors and atherosclerotic lesions. A review of autopsy studies. Arteriosclerosis, Thrombosis, and Vascular Biology. 1983;3:187-19835. Austen WGMD, Edwards JEMD, Frye RLMD, Gensini GGMD, Gott VLMD, Griffith LSCMD, McGoon DCMD, Murphy MLMD, Roe BBMD. A reporting system on patients evaluated for coronary artery disease. Circulation. 1975;51:Page5-Page4036. Lee JT, Ideker RE, Reimer KA. Myocardial infarct size and location in relation to the coronary vascular bed at risk in man. Circulation. 1981;64:526-53437. White CW, Wright CB, Doty DB, Hiratza LF, Eastham CL, Harrison DG, Marcus ML. Does visual interpretation of the coronary arteriogram predict the physiologic importance of a coronary stenosis? New England Journal of Medicine. 1984;310:819-82438. Califf RM, Phillips HR, Hindman MC, Mark DB, Lee KL, Behar VS, Johnson RA, Pryor DB, Rosati RA, Wagner GS, Harrel FE. Prognostic value of a coronary artery jeopardy score. Journal of the American College of Cardiology. 1985;5:1055-106339. Seiler C, Kirkeeide RL, Gould KL. Measurement from arteriograms of regional myocardial bed size distal to any point in the coronary vascular tree for assessing anatomic area at risk. Journal of the American College of Cardiology. 1993;21:783-797

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