Post on 01-Apr-2015
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