Show notes
CardioNerds (Amit Goyal and Daniel Ambinder), ACHD series co-chair Dr. Agnes Koczo (UPMC), and episode FIT lead, Dr. Natasha Wolfe (Washington University) join Dr. Ari Cedars (Director of the Adult Congenital Heart Disease Program at Johns Hopkins) for a discussion about coarctation of the aorta.
In this episode we discuss the presentation and management of unrepaired and repaired coarctation of the aorta in adults. We discuss the unique underlying congenital anatomy of coarctation and how that impacts physiology, clinical presentation, and diagnostic findings. We discuss the importance of long-term routine follow-up and screening of patients (including those who have been “repaired”) for common complications such as hypertension, re-coarctation, and aneurysm development. We end with a discussion of treatment options for coarctation and its complications.
Audio editing by CardioNerds Academy Intern, Dr. Maryam Barkhordarian.
The CardioNerds Adult Congenital Heart Disease (ACHD) series provides a comprehensive curriculum to dive deep into the labyrinthine world of congenital heart disease with the aim of empowering every CardioNerd to help improve the lives of people living with congenital heart disease. This series is multi-institutional collaborative project made possible by contributions of stellar fellow leads and expert faculty from several programs, led by series co-chairs, Dr. Josh Saef, Dr. Agnes Koczo, and Dr. Dan Clark.
The CardioNerds Adult Congenital Heart Disease Series is developed in collaboration with the Adult Congenital Heart Association, The CHiP Network, and Heart University. See more
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Pearls
Coarctation of the aorta can occur as a discrete stenosis or as a long and hypoplastic hypoplastic aortic arch segment. Most commonly it is a discrete stenosis located at the insertion site of the ductus arteriosus just distal to the left subclavian artery.Three quarters of patients with coarctation of the aorta also have a bicuspid aortic valve.Hypertension is the most common long-term complication of coarctation of the aorta, whether repaired or unrepaired. Unrepaired coarctation is a rare cause of secondary hypertension in young adults with a difference in upper extremity and lower extremity BP by ≥ 20 mmHg. Systemic hypertension may not be consistently identifiable at rest in those with repaired coarctation, thus guidelines recommend ambulatory blood pressure monitoring or stress testing to identify hypertension with exertion.Chest and brain imaging via CT or MRI should be done every 5-10 years to screen for other long-term complications including re-coarctation (rate ~11%), aortic aneurysm development (higher risk in those with concurrent bicuspid aortic valve), pseudoaneurysm, aortic dissection, and cerebral aneurysms.Repair of coarctation or re-coarctation is indicated for patients who are hypertensive with a BP gradient ≥ 20 mmHg (Class I recommendation). Catheter-based stenting is the preferred approach when technically feasible.
Show notes
1. What is the proposed embryologic origin of coarctation of the aorta?
The aortic arch and its branches develop at 6-8 weeks fetal gestation. We all start with six aortic arches that go on to become the great arteries of the head and neck. The 4th arch forms the thoracic aortic arch and isthmus. The 6th arch persists as the proximal pulmonary arteries and ductus arteriosus. Thoracic aortic coarctation is therefore a manifestation of abnormal embryologic development of the 4th and 6th arches.There are two main theories regarding how aortic coarctation occurs.The first is the “ductus tissue theory”, which proposes that coarctation develops as the result of migration of ductal smooth muscles cells in the periductal aorta, with subsequent constriction and narrowing of the aortic lumen.The “hemodynamic theory” proposes that coarctation develops because of hemodynamic disturbances from other left sided congenital lesions that reduce the volume of blood flow through the fetal aortic arch – recall the “no flow, no grow” tenet.In all likelihood, both are true and play a role in aortic coarctation embryologic development.
2. What are the key features of aortic coarctation anatomy?
Coarctation is, strictly speaking, a congenital narrowing of the aorta.Most commonly, this occurs at the insertion of the ductus arteriosus just distal to the left subclavian artery and is more of an isolated ridge or shelf that causes obstruction and narrowing.There are several other variants, however and include discrete thoracic lesions, long-segmental defects, tubular hypoplasia, and more rarely, coarctation located in the abdominal aorta.Other common congenital anomalies found in patients with aortic coarctation include supra- or subaortic stenosis, Shone complex (a series of left-sided obstructive lesions), and hypoplastic left heart syndrome. Enjoy Episode #121 for more on Shone Complex.Patients with Turner Syndrome and Williams Syndrome have high rates of aortic coarctation.
3. What are the hemodynamic consequences of aortic coarctation?
While coarctation can be severe, it is often well tolerated in utero given ~2/3 of cardiac output flows through the ductus arteriosus into the descending thoracic aorta, bypassing the area of narrowing.After birth, however, increasing amounts of cardiac output must bypass the area of constriction. The severity of narrowing correlates with the amount of added afterload beyond what we would expect to see in normal hemodynamics. The consequences thus vary depending on this severity, from asymptomatic to mild hypertension to heart failure and overt cardiogenic shock.Compensatory mechanisms the heart can use to counteract this extra afterload are 1) hypertrophy and 2) increasing LV dimensions – neither of which are ideal for a young patient!The systemic circulation may compensate for the coarctation by developing collateral blood flow involving the intercostal, internal mammary, and scapular vessels.Upper extremity systemic arterial hypertension with a 20-mmHg gradient between the upper and lower extremitiesDelayed and diminished femoral arterial pulses, rarely with symptoms of claudicationSystolic murmur at left sternal border with radiation to the back and possible thrill in suprasternal notch reflective of high flows through the coarctPossible continuous murmur from development of arterial collaterals
4. How might an adult with a history of repaired coarctation of the aorta present?
10-20% of those with repaired coarctation go on to develop hypertension in adulthood. This is an important risk factor in these patients for premature coronary artery disease, stroke, cardiomyopathy, and aneurysm (aortic and cerebral) rupture.Even in those with normal blood pressure at rest, many have hypertension that can be unmasked with exercise.~11% of patients develop re-coarctation.Patients are at risk of developing aneurysm, aortic dissection, or pseudoaneurysms at the site of prior repair (risk is higher in those with concurrent bicuspid aortic valve).~10% of patients with coarctation of the aorta develop cerebral aneurysms and in 5% of coarctation patients, the cause of death is ruptured cerebral aneurysm.
5. What are long-term considerations for coarctation of the aorta?
In patients with unrepaired coarctation or re-coarctation with a BP gradient ≥ 20 mmHg (Class I recommendation) and hypertension, repair is indicated with transcatheter stenting preferred when technically feasible.In patients with repaired coarctation and normal BP at rest, guidelines recommend consideration of ambulatory blood pressure monitoring or exercise stress test to diagnose hypertension with exertion. If this is found, treatment with low dose anti-hypertensive is indicated.Routine chest and brain imaging via CT or MRI every 5-10 years is indicated to screen for long-term complications at the site of prior repair and for cerebral aneurysm development.Surgical management is indicated for ascending aorta aneurysm 50mm in diameter or those with rapid progression due to high risk of rupture or dissection.
References
Stout KK, Daniels CJ, Aboulhosn JA, Bozkurt B, Broberg CS, Colman JM, Crumb SR, Dearani JA, Fuller S, Gurvitz M, Khairy P, Landzberg MJ, Saidi A, Valente AM, Van Hare GF. 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2019 Apr 2;73(12):e81-e192. doi: 10.1016/j.jacc.2018.08.1029. Epub 2018 Aug 16. Erratum in: J Am Coll Cardiol. 2019 May 14;73(18):2361-2362. PMID: 30121239.Baumgartner H, De Backer J, Babu-Narayan SV, Budts W, Chessa M, Diller GP, Lung B, Kluin J, Lang IM, Meijboom F, Moons P, Mulder BJM, Oechslin E, Roos-Hesselink JW, Schwerzmann M, Sondergaard L, Zeppenfeld K; ESC Scientific Document Group. 2020 ESC Guidelines for the management of adult congenital heart disease. Eur Heart J. 2021 Feb 11;42(6):563-645. doi: 10.1093/eurheartj/ehaa554. PMID: 32860028.Kenny D, Hijazi ZM. Coarctation of the aorta: from fetal life to adulthood. Cardiol J. 2011;18(5):487-95. doi: 10.5603/cj.2011.0003. PMID: 21947983.Nguyen L, Cook SC. Coarctation of the Aorta: Strategies for Improving Outcomes. Cardiol Clin. 2015 Nov;33(4):521-30, vii. doi: 10.1016/j.ccl.2015.07.011. Epub 2015 Aug 29. PMID: 26471817.Horlick EM, McLaughlin PR, Benson LN. The adult with repaired coarctation of the aorta. Curr Cardiol Rep. 2007 Jul;9(4):323-30. doi: 10.1007/BF02938381. PMID: 17601399.