Connie Tsao, MD Noninvasive/Echo Conference July 29, 2009

Definition  Discrete narrowing of the thoracic aorta Distal 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 malformations Familial occurrence  VSD  PDA  Aortic stenosis  Mitral stenosis  Intracerebral aneurysm Associations

Pathogenesis  Congenital Most common  Acquired Inflammation/Arteritis, eg, Takayasu ○ Mid-thoracic, abdominal aorta Severe 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 areas Cystic medial necrosis: disarray of elastic tissue

Being born can be a problem  In utero: High PVR, low SVR 90% cardiac output:  PDA  descending ao  At birth: ↑ SVR ↓ PVR PFO and PDA closure CO through ascending aorta

Clinical Manifestations  Neonates Absent/delayed femoral pulse Differential cyanosis if severe and large PDA R  L shunt Heart failure/ shock in first day of life  Children Delayed diagnosis 2/2 mild coarctation Chest pain with exercise, cold extremities, claudication  Adults Hypertension Autoregulatory vasodilation/constriction maintains blood regional flow Claudication

Differential Blood Pressure  Classic findings Hypertension in upper extremities Decreased/ delayed femoral pulse Low blood pressure in lower extremities  Etiology of hypertension Mechanical obstruction ↑ renin secretion  volume expansion

Neurologic Comorbitities  Increased frequency of intracranial aneurysms Prospective study of 100 pts: 10% aneurysms Usually years of age Persistence 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  weeks of gestation  Helpful identifiers: Long segment Small LV Small mitral annulus Dilated 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, 3 rd Ed

Predictors of Fetal Coarctation  44 fetuses with suspected coarct Mean 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 fetus B: 38 week postmortum C: 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 severity RVH  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: Hypertension Heart failure Peak gradient >20 mm Hg Collateral 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 1945 Omeje 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% patients Young infants Inadequate 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 gradient 2 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 1997Ledesma 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-dilation Isthmus 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 morbidity Endovascular 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 2002 Fawzy 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= (A s -A d )/[A d (P s -P d )1333]*10 7  Stiffness index= [ln(P s /P d )]/[(D s -D d )/D d ] Circulation 2005;111:

 ↑ ascending aortic stiffness, ↓ distensibility Persist 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 Mean age at f/u 34 Survival rates 91%, 84%, 72% at 10, 20, 30 years after surgery Best prognostic factors age, preoperative BP  Euro Heart Study 551 pts with coarctation, 90% prior repair, , followed until 2004 Mean age 26 5-year mortality 0.7% Cohen M et al, Circ 1989 Engelfriet P et al, Eur Heart J 2005

Summary  Aortic coarctation is common (6-8%) among congenital CV abnormalities Associated 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 hypertension Surgery for <6 mos, angioplasty ± stent if older  Favorable longterm outcomes HTN, recoarctation risks