connie tsao, md noninvasive/echo conference july 29, 2009

Connie Tsao, MD

Noninvasive/Echo Conference

July 29, 2009

Definition Discrete narrowing

of the thoracic aortaDistal to left

subclavian artery○ At ductus arteriosis

Proximal to left subclavian artery

Abdominal aorta

Rarely long segment or tubular hypoplasia

Epidemiology

6-8% of all congenital heart defects

Male: Female 2-5:1 Sporadic; rare

familial

Turner Syndrome: XO Bicuspid aortic valve

30-40% incidence LVOT obstruction

malformationsFamilial occurrence

VSD PDA Aortic stenosis Mitral stenosis Intracerebral aneurysm

Associations

Pathogenesis

CongenitalMost common

Acquired Inflammation/Arteritis, eg, Takayasu

○ Mid-thoracic, abdominal aortaSevere atherosclerosis

Pathogenesis/Pathology Mechanism unknown

Genetic defects?Intrauterine defects, eg impaired blood flow

altered endothelial development? Medial thickening + intimal hyperplasia

posterolateral ridge encircling lumen Surgical specimens:

↑ collagen↓ smooth muscle mass in pre vs poststenotic areasCystic medial necrosis: disarray of elastic tissue

Being born can be a problem In utero:

High PVR, low SVR90% cardiac output:

PDA descending ao

At birth:↑ SVR↓ PVRPFO and PDA closureCO through ascending

aorta

Clinical Manifestations Neonates

Absent/delayed femoral pulseDifferential cyanosis if severe and large PDA RL shuntHeart failure/ shock in first day of life

ChildrenDelayed diagnosis 2/2 mild coarctationChest pain with exercise, cold extremities, claudication

AdultsHypertensionAutoregulatory vasodilation/constriction maintains blood

regional flowClaudication

Differential Blood Pressure Classic findings

Hypertension in upper extremitiesDecreased/ delayed femoral pulseLow blood pressure in lower extremities

Etiology of hypertensionMechanical obstruction↑ renin secretion volume expansion

Neurologic Comorbitities

Increased frequency of intracranial aneurysmsProspective study of 100 pts: 10% aneurysmsUsually 10-30 years of agePersistence after normalization of BP

Dilation of collateral spinal arteries compress spinal cord

Connolly HM et al, Mayo Clin Proc 2003

Cardiac Exam

Often normal without co-existing defects Continuous murmur if large collateral

vessels Systolic ejection click and/or murmur if

bicuspid aortic valve Short midsystolic murmur from flow

across coarctation itself

Prenatal Diagnosis

16-18 weeks of gestation Helpful identifiers:

Long segmentSmall LVSmall mitral annulusDilated RV

Flow through ductus difficult to detect coarctation

Echocardiography

High parasternal, suprasternal long axis Shelf within lumen of thoracic aorta Color and pulse wave doppler to locate

area Continuous wave doppler to detect

maximum flow velocity

Echo Characteristics

Low amplitude continuous doppler flow in descending aorta below coarctation

Persistence of flow in diastole

Otto, CM, Textbook of Clinical Echocardiography, 3rd Ed

Predictors of Fetal Coarctation 44 fetuses with

suspected coarctMean 24 wks

gestation

Isthmus Z score <-2 Isthmus to ductal

ratio <0.74 Disturbance in

doppler flow at isthmus

Matsui H, et al, Circulation 2008

Fetal Diagnosis

A: 27 week fetusB: 38 week postmortumC: Continuous low velocity doppler at isthmus

Matsui H et al, Circ 2008

Normal Adult Aortic Arch

27 year old man with coarctation s/p balloon angioplasty in 1996

37 year old woman with history of coarctation s/p surgery as child

Other diagnostic modalities ECG

Varies with severityRVH

CXR MRI

CXR Infants with severe

disease: cardiomegaly, heart failure

Notching posterior ribs: erosion by collaterals

“3” Sign: Indentation of aortic wall with pre and poststenotic dilatation

MRI

Cardiac Catheterization

Fawzy ME et al, JACC 2004

Clinical Management

Neonate in heart failure:Medial rx prior to surgery: Prostaglandin E1

PDA open, inotropic agents

Indications for intervention:HypertensionHeart failurePeak gradient >20 mm HgCollateral circulation on MRI

Surgical Options

Resection with end-to-end anastamosis

+/- graft material

Developed in 1945 Especially in older

children, adults

Gross et al, Surgery 1945Omeje IC et al, Images Paediatr Cardiol 2004

Subclavian flap aortoplasty

Long-segment of coarctation

Prothetic patch aortoplasty

Associated with aortic aneurysm/ rupture

At Surgery

Surgical Outcomes

Mortality rare Postoperative paradoxical hypertension,

left recurrent laryngeal nerve paralysis, phrenic nerve injury, subclavian steal

Re-coarctation in 5-14% patientsYoung infantsInadequate aortic wall growth

Balloon Angioplasty (BA)

Preferred for children, adults Native coarctation or after

surgery Not infants <6 mos Initial success in 80-90%

Gradient ≤ 20 mm Hg

Rao PS,J Pediatrics 1987; Beekman RH et al, JACC 1987

Rao PS et al, Brit Heart J 1986

BA- Potential Complications 20% (up to 35%) incidence residual

pressure >20 mm Hg Up to 25% incidence recoarctation 1-3% dissection, rupture 2-8% incidence aneurysm in f/u up to 5 yrs Up to 15% femoral artery complications

Rao PS et al, JACC 1996; Fletcher SE et al, JACC 1995; Tynan M et al, Am J Cardiol 1990; Saba SE et al, J Invasive Cardiol 2000

54 patients (40 male), 22±7 (15-55) years Indication: Discrete coarctation ± pressure >20 mm

Hg, + systemic hypertension unresponsive to medical rx

Successful procedure in 49 (93%)Surgery in 3 pts: dissection, aneurysm, persistent gradient2 lost to f/u

49 followed: Repeat cath in 1 year; yearly BP, ECG, CXR, echo, MRI Median 10.2 (9.1 ± 4.4 years) up to 15.3 years

JACC 2004

Results

BP normal without medications in 31 pts (63%) Aneurysm in 4 pts at 1 year f/u (7.8%)

Prior studies 2-6% occurrence

Fawzy ME et al, JACC 2004

Angioplasty vs. Surgery 36 children (3-10 years) 20 BA/ 16 surgery Both 86%↓ peak systolic pressure gradient Similar frequency of bleeding; surgery with 2

neurologic events (paraplegia, vocal cord paralysis)

Angioplasty 20% incidence aneurysm Restenosis after angioplasty 25% (vs 6%)

Associated with isthmus/desc ao <0.65 and post-procedure pressure ≥12 mm Hg

Shaddy RE et al, Circ 1993

Angioplasty vs. Surgery, cont’d Extended follow up (10.6±4.7 years BA

and 11.3±3.7 years surgery) 11 BA, 10 surgery No difference in resting BP, exercise

performance, MRI dimensions of arch, need for repeat intervention

BA: 35% incidence of aneurysm (none for surgery)Some forming after 5 years

Cowley CG, et al, Circ 2005

Angioplasty vs. Surgery, cont’d Retrospective review of 4 Canadian tertiary

centers, 12±10 years 50 BA (19 stent) vs. 30 surgery F/u 38 months Similar reduction in peak systolic gradient Surgery: procedure-related complications BA:

32% reintervention (none in surgery group)Aneurysm in 24% (vs. none in surgery)

Rodes-Cabau J et al, Am Heart J 2007

Stent Placement Initially for those

with residual gradient after BA

↑ lumen diameter ↓ residual gradient Dilate stent with

growth of aorta Not for pts <25 kg

Ebeid MR et al, JACC 1997 Ledesma M et al, Am J Cardiol 2001

Stent Placement Retrospective review of 71 consecutive pts

(44M, mean 22±6 years), 52 native coarctation 74 stents implanted Diameter 8±3 16±4 mm Peak systolic gradient 39±15 3.6±5 mm Hg Mean f/u 3.1 years– MG 13±4 mm Hg 4 pts required stent re-dilation Complications: 1 death (rupture, dislodge),

1 aneurysm

Chessa M et al, Eur Heart J 2005

Longterm Morbidities- Recoarctation

5-14% after surgery 20-30% BA without stenting Predictors

Neonates and <1 year of age<3.5 mm pre-dilation, <6 mm post-dilationIsthmus hypoplasia

Monitor for HTN, gradient >20 mm Hg Intervention: stenting vs. surgery (arch

hypoplasia, aneurysm)

Longterm– Aneurysms Patch repair (up to 90% of all aneurysms) 2-8% with BA Coexisting bicuspid aortic valve/dilated ao Medial tissue abnormalities MRI 1 month, 6 months, then q3-5 years Treatment:

Surgery associated with neurologic morbidityEndovascular stenting– no morbidity/ mortality in

small study (6 pts)

Ince H et al, Circ 2003

Longterm– Hypertension

Persistent or inappropriate ↑ with exercise BP response more common if repair in

childhood ↑ frequency if repair > age 20 Structural/functional abnormalities

↓ compliance

Toro-Salazar OH et al, Am J Cardiol 2002Fawzy ME et al, JACC 2004

Aortic Stiffness and Coarctation

17 newborns with coarctation (no other congenital defects) studied pre and post (10d) surgery, compared with 17 controls

M-mode echo, aortic pulse pressure Ascending + descending aorta measurements Distensibility= (As-Ad)/[Ad(Ps-Pd)1333]*107

Stiffness index= [ln(Ps/Pd)]/[(Ds-Dd)/Dd] Circulation 2005;111: 3269-73

↑ ascending aortic stiffness, ↓ distensibilityPersist early postoperatively despite surgery

Innate vascular defects? Longterm consequences not addressed

Pregnancy

Uncommon risks: aortic rupture/ dissection, intracranial hemorrhage, CHF

Careful monitoring BP BA or stenting for uncontrolled HTN Higher risk of miscarriage, preeclampsia

Vriend JW et al, Eur Heart J 2005

Survival Mayo Clinic

571 pts s/p surgery for coarctation 1946-1981Mean age at f/u 34Survival rates 91%, 84%, 72% at 10, 20, 30 years

after surgeryBest prognostic factors age, preoperative BP

Euro Heart Study551 pts with coarctation, 90% prior repair, 1998-

2000, followed until 2004Mean age 265-year mortality 0.7%

Cohen M et al, Circ 1989Engelfriet P et al, Eur Heart J 2005

Summary Aortic coarctation is common (6-8%) among

congenital CV abnormalitiesAssociated with bicuspid aortic valve

Intrinsic defects in aortic tissue abnormalities in tissue compliance

Repair in childhood or as soon as diagnosed in adulthood↓ risk persistent hypertensionSurgery for <6 mos, angioplasty ± stent if older

Favorable longterm outcomes HTN, recoarctation risks