International Journal of Cardiology 176 (2014) e13–e14

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International Journal of Cardiology

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Letter to the Editor

Intermittent left ventricular assist device inflow tract obstruction byprolapsing papillary muscle detected by multi-detector computedtomography (MDCT)

Pranjal Kumar Boruah a,⁎, Dhiraj Baruah b, Claudius Mahr b, Nunzio Gaglianello b, Kaushik Shahir b

a Wright Center for Graduate Medical Education, Scranton, PA, United Statesb Medical College of Wisconsin, Milwaukee, WI, United States

⁎ Corresponding author at:Wright Center for Graduate18505, United States.

E-mail address: boruah.pranjal@gmail.com (P.K. Borua

http://dx.doi.org/10.1016/j.ijcard.2014.06.0930167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved

a r t i c l e i n f o

Article history:

Received 7 May 2014Accepted 29 June 2014Available online 9 July 2014

Keywords:Left ventricular assist device (LVAD)Mechanical circulatory support (MCS)Heart failureMulti-detector computed tomography (MDCT)Papillary muscle prolapseMechanical obstruction

was 28%. His post-operative course was complicated by coagulopathyand a mediastinal hematoma for which he underwent re-explorationand evacuation of hematoma. He did well for approximately 3 monthsas an outpatient, but presented to our advanced heart failure andVAD clinic with acute onset dizziness and generalized weakness.He also had a sub therapeutic international normalized ratio (INR)of 1.4, with normal hemolysis parameters (LDH, haptoglobin andplasma free hemoglobin) and normal pump function upon interroga-tion and heartware engineering analysis. He was found to have hy-pertensive urgency with his MAP's N100 mm Hg and his deviceinterrogation demonstrated multiple suction alarms. He was startedon anticoagulation with low molecular weight heparin for his sub-

Mechanical circulatory support (MCS) with left ventricular assistdevices (LVAD) is increasingly being used for the treatment ofadvanced heart failure either as destination therapy or as a bridgeto transplantation. Mechanical obstruction of an LVAD either byclot formation within the motor, external compression of the out-flow graft or obstruction of the inflow cannula are important causesof morbidity and mortality for patients implanted with an LVAD.Papillary muscle prolapse is an extremely rare cause of mechanicalobstruction of LVAD inflow cannula [1,2] and transthoracic echocar-diography (TTE) has been used primarily for the diagnosis. We de-scribe a case of obstruction of the inflow cannula of a heartwaredevice (HVAD) in a 62-year-old gentleman listed for cardiac trans-plantation detected by multi-detector CT (MDCT). To the best ofour knowledge, this is the first time that retrospectively gated cardi-ac CT has been used to detect this exceedingly rare phenomenon.

The 62-year-old gentleman with past medical history of diabetesandhypertensionwith severe ischemic cardiomyopathy underwent im-plantation of a heartware device as a bridge to cardiac transplantation.He was INTERMACS Profile 3 at the time of implantation. He alsounderwent coronary artery bypass graft (saphenous vein graft to poste-rior descending artery) in an effort to revascularize the right ventricle to

Medical Education, Scranton, PA

h).

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prevent right ventricular dysfunction given that his RVEF by cardiacMRI

therapeutic INR. The suction alarms could be reproduced by theValsalva. While in the hospital; he developed multiple episodes ofnon-sustained ventricular tachycardia. Anti-hypertensive medica-tion was titrated to keep mean arterial pressure between 70 and80 mm Hg. He was also started on Coumadin with a goal of INRbetween 2.0 and 3.0. TTE demonstrated opening of the aortic valveat an HVAD speed of 2800; however because of poor echo windows,optimal evaluation of the inflow and outflow cannulas could not beperformed. Given his recurrent suction events a CT angiography ofthe chest was performed. CT scan was performed in a MDCT scanner(Discovery CT750 HD, General Electronic) using retrospective gating.The following parameters were used — kV 120, tube current652 mAs, pitch 0.20, and 130 mL of Isovue 370 contrast. Reformattedimages in different planes were generated in a dedicated worksta-tion (Advantage Windows Workstation). Gated cardiac CT revealedintermittent systolic prolapse of the posterior papillary muscle intothe inflow cannula of the LVAD (Fig. 1). This was thought to be thecause of intermittent flow obstruction. There was no evidence of ananastomotic leak or occlusion of the outflow graft.

The rotational speed of the HVAD was decreased to 2300 rpm,which decreased the frequency of suction alarms. The patient contin-ued to experience non-sustained ventricular tachycardia withoutany evidence of hemodynamic instability. The HVAD speed wasdecreased to 2000 rpm and the mean arterial pressure (MAP) wasmaintained between 60 and 80 mm Hg. This led to a significantdecrease in the suction alarms and in the episodes of non-sustainedventricular tachycardia. Patient's hospital course was complicatedby an episode of transient ischemic attack (TIA) despite therapeutic

(a)

(b)

Fig. 1. Diastolic (a) and systolic (b) phases of the retrospectively gated CT (DiscoveryCT750 HD, General Electric) in 2-chamber short axis reformats showing intermittentpapillary muscle intrusion in the LVAD inflow (arrow).

e14 P.K. Boruah et al. / International Journal of Cardiology 176 (2014) e13–e14

INR, with no residual neurologic deficits. This was attributed to hisintermittent mechanical obstruction by the protruding posteriorpapillary muscle into the inflow tract. Since he continued to have

suction events and ventricular tachycardia with no evidence ofpump thrombosis and normal functioning pump parameters, it waselected to list the patient as UNOS status 1AE in anticipation of cardi-ac transplantation. He is awaiting heart transplantation.

Obstruction to the inflow cannula of LVAD may result from technicalerror at the time of implantation,migration or reverse ventricular remod-eling [3]. Echocardiography has traditionally been used for the evaluationand diagnosis of mechanical complications of LVAD [4]. Cardiac CT withretrospective electrocardiographic (EKG) gating offers an alternativenon-invasive high resolution imaging modality for dynamic evaluationof cardiovascular structures. It is especially advantageous over echocardi-ography in the imaging of LVAD because it is not limited by acoustic win-dowwhich is an important limitation of TTE. This allows better anatomicassessment of LVAD positioning within the left ventricular cavity as wellas positioning of the outflowgraft. It can be used to supplement 2-D echo-cardiography especially in the setting where accurate information cannotbe obtained because of poor acoustic window. The limitations of cardiacCT include the potential of nephrotoxicity because of the use of iodinatedcontrast agents, radiation and potential of contrast allergy. It might beconsidered as the first line of assessment or a problem solving tool in pa-tients with suspected mechanical obstruction of LVAD in patients knownto have poor acoustic windows on 2D echocardiogram.

Conflict of interest

The authors report no relationships that could be construed as aconflict of interest.

Appendix A. Supplementary data

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.ijcard.2014.06.093.

References

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[2] Oda N, Kato TS, Niwaya K, Komamura K. Unusual cause of left ventricular assist devicefailure: pendulating mass in the cavity. Eur J Cardiothorac Surg 2007;32:533.

[3] Raman SV, Sahu A, Merchant AZ, et al. Non-invasive assessment of left ventricular as-sist devices with cardiovascular computed tomography and impact onmanagement. JHeart Lung Transplant 2010;29:79–85.

[4] Horton SC, Khodaverdian R, Powers A, et al. Left ventricular assist devicemalfunction:a systematic approach to diagnosis. J Am Coll Cardiol 2004;43:1574–83.