Residency · Residency · Medicine Pediatrics
Congenital Heart Disease in Adults (ACHD)
Overview
Adults with congenital heart disease (ACHD) now outnumber children with CHD due to advances in surgical repair and medical management. There are over 1.4 million adults living with CHD in the United States. Med-Peds physicians frequently encounter these patients and must recognize late complications of repaired or palliated congenital heart defects.
Epidemiology
CHD affects approximately 1% of all live births, translating to 8 to 10 per 1,000 newborns. Thanks to surgical advances, over 90% of children with CHD now survive to adulthood, and the ACHD population is growing at approximately 5% per year. Unfortunately, many of these patients are "lost to follow-up" between pediatric and adult care, and a significant proportion have no regular cardiology follow-up at all.
Classification of Congenital Heart Defects
| Complexity | Examples | Prognosis / Follow-up |
|---|---|---|
| Simple | Isolated secundum ASD, small VSD, mild pulmonic stenosis, ligated PDA, repaired ASD/VSD without residua | Most favorable; periodic surveillance |
| Moderate | Repaired AV canal, repaired coarctation, repaired TOF, Ebstein anomaly, sinus venosus ASD | Higher late complication burden; more frequent cardiology follow-up |
| Severe | Single ventricle/Fontan, TGA (post-arterial switch or Mustard/Senning), truncus arteriosus, Eisenmenger syndrome, pulmonary atresia | Highest risk for late morbidity/mortality; specialized ACHD center management |
Simple Lesions
Simple lesions include isolated secundum atrial septal defects, small ventricular septal defects, mild pulmonic stenosis, previously ligated patent ductus arteriosus, and repaired ASDs or VSDs without residual defects. These patients generally have the most favorable long-term prognosis, though they still warrant periodic surveillance.
Moderate Complexity Lesions
Moderate complexity lesions encompass repaired atrioventricular canal defects, repaired coarctation of the aorta, repaired tetralogy of Fallot, Ebstein anomaly, and sinus venosus ASDs. These patients face a higher burden of late complications and require more frequent cardiology follow-up.
Severe Complexity Lesions
The most complex lesions include single ventricle physiology with Fontan circulation, transposition of the great arteries (whether post-arterial switch or Mustard/Senning repair), truncus arteriosus, Eisenmenger syndrome, and pulmonary atresia. These patients are at highest risk for late morbidity and mortality and ideally should be managed at specialized ACHD centers.
Late Complications in ACHD
Arrhythmias
Arrhythmias are the most common reason for hospitalization in ACHD patients. Atrial arrhythmias, including intra-atrial reentrant tachycardia, atrial fibrillation, and atrial flutter, are especially common after atrial surgery such as Fontan, Mustard/Senning, or ASD repair. Ventricular arrhythmias are particularly concerning in repaired tetralogy of Fallot, where a QRS duration greater than 180 milliseconds is a recognized risk factor for sudden cardiac death. Conduction abnormalities, including complete heart block, may develop after VSD repair or in patients with congenitally corrected transposition of the great arteries. Pacemaker and ICD management in these patients requires careful consideration of the often-unusual cardiac anatomy.
Heart Failure
Heart failure in ACHD takes several forms. Systemic right ventricle failure occurs in patients with congenitally corrected transposition or those who underwent Mustard/Senning repair. Single ventricle patients with Fontan circulation may develop Fontan failure, which manifests as protein-losing enteropathy, plastic bronchitis, or progressive liver fibrosis. Volume overload from residual shunts or valvular regurgitation is another common mechanism. Notably, the evidence base for guideline-directed medical therapy (such as ACE inhibitors and beta-blockers) is limited for systemic right ventricle or single ventricle failure. Heart transplantation in ACHD patients presents unique challenges related to complex anatomy and multiple prior sternotomies.
Eisenmenger Syndrome
Eisenmenger syndrome represents the end-stage of a longstanding left-to-right shunt, in which irreversible pulmonary hypertension develops and the shunt reverses direction, causing cyanosis. Complications include erythrocytosis (though phlebotomy should be avoided unless there are symptoms of true hyperviscosity), hemoptysis, brain abscess, paradoxical embolism, and gout. Pulmonary vasodilator therapy with agents like bosentan and sildenafil can improve functional capacity. Pregnancy is contraindicated, carrying a maternal mortality rate of 30 to 50%.
Endocarditis
ACHD patients carry an elevated lifelong risk of infective endocarditis. Current AHA guidelines recommend prophylaxis only for the highest-risk lesions: unrepaired cyanotic CHD, lesions repaired with prosthetic material or a device within the first six months, repaired CHD with residual defects adjacent to prosthetic material, prior endocarditis, and cardiac transplant recipients with valvulopathy.
Aortopathy
Aortopathy is a significant concern in several ACHD populations. Patients with repaired coarctation may develop residual or recurrent coarctation, aortic aneurysm, or complications related to a bicuspid aortic valve. Those with repaired tetralogy of Fallot are at risk for aortic root dilation. Connective tissue disorders such as Marfan, Turner, and Loeys-Dietz syndromes carry associated CHD with progressive aortopathy. Imaging surveillance with MRI or CT angiography is essential.
Reproductive Considerations
Pregnancy risk in ACHD should be stratified using the modified WHO classification. WHO Class IV conditions, in which pregnancy is contraindicated, include Eisenmenger syndrome, severe systemic ventricular dysfunction, severe aortic stenosis, and Marfan syndrome with an aortic root diameter greater than 45 millimeters. Anticoagulation management during pregnancy requires careful planning, and a multidisciplinary cardio-obstetrics team is essential. Genetic counseling should be offered, as the recurrence risk of CHD in offspring of an affected parent is approximately 3 to 5%.
The Fontan Circulation: A Special Population
The Fontan circulation is a palliative circuit designed for single ventricle physiology, in which passive pulmonary blood flow occurs without a subpulmonary ventricle. The chronically elevated central venous pressure leads to a cascade of multisystem complications. Fontan-associated liver disease (FALD) progresses from fibrosis to cirrhosis and carries a risk of hepatocellular carcinoma. Protein-losing enteropathy manifests as edema, ascites, and immunodeficiency. Plastic bronchitis produces lymphatic casts in the airways. Fontan-associated kidney disease adds further complexity. These patients require lifelong surveillance with liver imaging and laboratory monitoring. Fontan failure is the leading indication for heart transplant in the ACHD population.
Diagnostic Approach in ACHD
A comprehensive history that captures all prior surgeries, catheterizations, and complications is the foundation of ACHD care. Physical examination should note surgical scars, cyanosis, clubbing, abnormal heart sounds, and hepatomegaly. Echocardiography is essential but often technically challenging due to altered anatomy. Cardiac MRI is the gold standard for volumetric assessment, particularly of right ventricular function. CT angiography is useful for evaluating aortopathy, coronary anomalies, and surgical planning. Cardiac catheterization provides definitive hemodynamic assessment and may allow for catheter-based intervention.
Workforce and Care Model Considerations
The ACC and AHA recommend that ACHD patients be seen at specialized ACHD centers, but only about 60 ACHD-accredited centers exist in the United States. Many patients are managed by general cardiologists without specific ACHD training, and there is ongoing debate about whether these patients are best served by adult cardiologists, pediatric cardiologists, or dedicated ACHD specialists. ACHD board certification has been available since 2015 through ABIM. Med-Peds physicians are well-suited to provide primary care coordination for ACHD patients, bridging the gap between subspecialty cardiac care and comprehensive general medicine.
<image>An anatomical illustration showing four panels of common repaired congenital heart defects seen in adult patients: (1) repaired Tetralogy of Fallot with a transannular patch and resultant pulmonary regurgitation, (2) Mustard/Senning repair of d-TGA showing atrial baffles redirecting blood flow with a systemic right ventricle, (3) Fontan circulation with a lateral tunnel connecting the inferior vena cava to the pulmonary artery, and (4) an Eisenmenger VSD with thickened pulmonary arteries and right-to-left shunting indicated by blue arrows.</image>
<image>A clinical timeline illustration showing the lifespan journey of a patient with Tetralogy of Fallot: neonatal cyanosis and diagnosis at birth, complete surgical repair at age 1, asymptomatic childhood, development of progressive pulmonary regurgitation and RV dilation in adolescence, arrhythmias and exercise intolerance in adulthood, and eventual pulmonary valve replacement. Key surveillance milestones (echocardiography, cardiac MRI, Holter monitoring) are marked along the timeline.</image>
<image>A medical illustration of Fontan-associated multisystem complications, showing a central diagram of the Fontan circuit with arrows pointing to affected organ systems: the liver (fibrosis and congestion), the gut (protein-losing enteropathy with intestinal lymphangiectasia), the lungs (plastic bronchitis with lymphatic casts), the kidneys (elevated venous pressure and reduced GFR), and the heart (atrial arrhythmias and ventricular dysfunction).</image>
Clinical Pearls
Every ACHD patient should carry a wallet card or have an accessible summary of their anatomy, surgeries, and current medications. The term "repaired" does not mean "cured," as virtually all ACHD patients require lifelong surveillance for late complications. The most common reason for hospitalization in ACHD is arrhythmia, not heart failure. A QRS duration greater than 180 milliseconds in repaired tetralogy of Fallot is a recognized risk marker for sudden cardiac death. An Eisenmenger patient should never be phlebotomized for erythrocytosis unless there are symptomatic hyperviscosity symptoms and the hematocrit is markedly elevated, and volume should always be replaced. Pregnancy risk stratification using the modified WHO classification should be discussed with all ACHD women of reproductive age. Cardiac MRI is the gold standard for right ventricular assessment, as echocardiography alone is often insufficient. Fontan-associated liver disease develops in virtually all Fontan patients, and screening for hepatocellular carcinoma should begin in adolescence or young adulthood.
References
- Stout KK, Daniels CJ, Perloff RK, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease. J Am Coll Cardiol. 2019;73(12):e81-e192.
- Marelli AJ, Ionescu-Ittu R, Mackie AS, et al. Lifetime prevalence of congenital heart disease in the general population from 2000 to 2010. Circulation. 2014;130(9):749-756.
- Khairy P, Aboulhosn J, Gurvitz MZ, et al. Arrhythmia burden in adults with surgically repaired tetralogy of Fallot: a multi-institutional study. Circulation. 2010;122(9):868-875.
- Goldberg DJ, Surrey LF, Glatz AC, et al. Hepatic fibrosis is universal following Fontan operation, and severity is associated with time from surgery. J Am Heart Assoc. 2017;6(4):e004809.
- Warnes CA, Williams RG, Bashore TM, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease. Circulation. 2008;118(23):e714-e833.
