Residency · Residency · Cardiothoracic Surgery
Adult Congenital Heart Disease: The Growing Population
Overview
Advances in pediatric cardiac surgery have created a rapidly growing population of adults with congenital heart disease (ACHD). There are now more adults than children living with CHD in developed countries, with an estimated 1.5 million adults in the United States. ACHD patients have unique surgical, medical, and psychosocial needs requiring specialized multidisciplinary care. Reoperative surgery in ACHD is common and technically challenging. The CT surgeon must understand the long-term sequelae of prior repairs and the indications for reintervention.
Epidemiology and Scope
The incidence of CHD is approximately 8-10 per 1,000 live births. With current surgical techniques, survival to adulthood exceeds 90% for most lesions. Simple lesions such as ASD, VSD, and PDA carry a near-normal life expectancy. Moderate complexity lesions such as TOF, coarctation, and Ebstein anomaly require lifelong surveillance. Complex lesions including single ventricle/Fontan, TGA, and truncus arteriosus represent a growing but vulnerable population. ACHD is projected to continue growing as surgical outcomes improve.
Classification of ACHD Complexity (ACC/AHA)
Simple complexity includes isolated small ASD, VSD, or PDA (repaired or unrepaired), repaired secundum ASD, sinus venosus ASD, or VSD without residua, and isolated aortic stenosis from bicuspid aortic valve. Moderate complexity includes repaired tetralogy of Fallot, repaired coarctation of the aorta, atrioventricular septal defect (repaired or unrepaired), Ebstein anomaly, and partial anomalous pulmonary venous return. Complex cases include Fontan circulation of any type, transposition after atrial switch (Mustard/Senning), transposition after arterial switch with significant residua, pulmonary atresia in all forms, truncus arteriosus, cyanotic CHD (unrepaired or palliated), and Eisenmenger syndrome.
<image>Spectrum of adult congenital heart disease complexity from simple (ASD, VSD) through moderate (TOF, coarctation) to complex (Fontan, Eisenmenger) with key management considerations for each level</image>
Unique Surgical Considerations in ACHD
Reoperative Sternotomy
Many ACHD patients have had multiple prior sternotomies, making reentry hazardous. The primary risks include the right ventricle being adherent to the posterior sternum (the most dangerous scenario), conduits or grafts adherent to the sternum, and aortic or PA dilation pressing against the sternum. Preoperative planning requires a lateral chest X-ray to assess the retrosternal space, a CT scan with contrast to delineate retrosternal structures and their relationship to the sternum, and femoral vessel assessment for peripheral cannulation. Technically, peripheral cannulation via the femoral artery and vein is established before sternotomy when retrosternal structures are at risk. An oscillating saw is used with careful depth control, followed by dissection under direct vision once the sternotomy is open. Alternative access through thoracotomy is considered for select procedures.
Adhesions and Altered Anatomy
Extensive mediastinal adhesions form from prior surgery, pericarditis, and fibrosis. Landmarks may be distorted by prior patches, conduits, and scar tissue. Detailed knowledge of the original operation and subsequent interventions is essential, and meticulous dissection with electrocautery is required to avoid injury to grafts, conduits, and phrenic nerves.
Collateral Vessels
Cyanotic patients develop extensive aortopulmonary collaterals that create significant hemorrhage risk during sternotomy and mediastinal dissection. Cell salvage and blood product availability are critical.
Common Reoperations in ACHD
Pulmonary valve replacement after TOF repair is the most common ACHD reoperation, indicated for severe pulmonary regurgitation with RV dilatation and/or dysfunction. Conduit replacement is needed for RV-PA conduits (homografts, Contegra) that degenerate over time in patients with TOF/PA, Rastelli, Ross, and truncus arteriosus repairs, with transcatheter valve-in-conduit options (Melody, SAPIEN) potentially delaying or avoiding reoperation. Fontan revision or conversion transforms an atriopulmonary Fontan to an extracardiac Fontan combined with arrhythmia surgery and pacemaker, representing a high-risk operation performed at specialized centers. Aortic root and valve reoperation addresses bicuspid aortic valve with aortopathy, ascending aortic aneurysm, aortic dissection, and failure of prior Ross procedure neoaortic root dilatation or autograft. Residual shunts and valvular lesions requiring reoperation include residual VSD after prior repair, progressive AV valve regurgitation (from AVSD, Ebstein, or cc-TGA), and subaortic stenosis.
<image>CT scan demonstrating reoperative planning for redo sternotomy in ACHD, showing RV conduit adherent to the posterior table of the sternum requiring peripheral cannulation strategy</image>
Arrhythmia Management
Arrhythmias are a leading cause of morbidity and mortality in ACHD. Atrial arrhythmias, including intra-atrial reentrant tachycardia (IART), atrial flutter, and atrial fibrillation, are common after Fontan, atrial switch, and ASD repair. They are poorly tolerated due to compromised hemodynamics, with catheter ablation serving as first-line therapy for drug-refractory arrhythmia and surgical ablation performed during concomitant operations. Ventricular arrhythmias, particularly VT in repaired TOF and post-ventriculotomy scars, carry risk factors including QRS greater than 180 ms, RV dysfunction, and prior palliative shunts. EP study and ablation are performed, with ICD placement for secondary prevention. Bradyarrhythmias including sinus node dysfunction (post-Mustard/Senning, Fontan) and surgical AV block require pacemaker implantation, with epicardial leads considered when transvenous access is unavailable.
Heart Transplantation in ACHD
ACHD is an increasingly common indication for heart transplantation, presenting unique challenges including complex anatomy requiring modified surgical technique, prior sternotomies with extensive adhesions, sensitization from HLA antibodies related to prior blood products and homografts, anomalous systemic and pulmonary venous anatomy, unique pulmonary vascular resistance considerations in Fontan patients, and heterotaxy with abnormal abdominal situs. Post-transplant outcomes are slightly lower than for non-ACHD recipients but are improving. Combined heart-liver transplantation is emerging for Fontan patients with advanced liver disease.
Modified WHO Pregnancy Risk Classification in ACHD
| mWHO Class | Risk Level | Examples | Recommendation |
|---|---|---|---|
| I | Low | Small ASD/VSD, repaired simple lesions | Routine obstetric care |
| II | Moderate | Repaired TOF, most valvular lesions | Specialist review each trimester |
| III | High | Fontan, mechanical valves, moderate-severe systemic ventricular dysfunction | Expert multidisciplinary care; frequent monitoring |
| IV | Contraindicated | Eisenmenger, severe systemic ventricular dysfunction, severe AS, Marfan (aorta > 45 mm) | Pregnancy contraindicated (maternal mortality 30-50% for Eisenmenger) |
Pregnancy in ACHD
Pregnancy significantly increases cardiovascular demands with a 30-50% increase in cardiac output. Risk stratification uses the modified WHO classification: mWHO I (low risk) includes small ASD/VSD and repaired simple lesions; mWHO II (moderate risk) includes repaired TOF and most valvular lesions; mWHO III (high risk) includes Fontan, mechanical valves, and moderate-severe systemic ventricular dysfunction; mWHO IV (contraindicated) includes Eisenmenger, severe systemic ventricular dysfunction, severe aortic stenosis, and Marfan with aorta greater than 45 mm. Preconception counseling is essential to discuss maternal and fetal risks, including recurrence of CHD in offspring (3-5%). Multidisciplinary cardio-obstetric team management is required, and anticoagulation management involves transitioning from warfarin (teratogenic in the first trimester) to LMWH or unfractionated heparin.
Specialized Multidisciplinary Care
ACHD care should be delivered at specialized centers with ACHD cardiologists (board-certified), congenital cardiac surgeons with adult experience, congenital cardiac anesthesiologists, electrophysiologists with ACHD expertise, advanced heart failure and transplant specialists, maternal-fetal medicine specialists, hepatologists (for Fontan liver disease), and psychosocial support including mental health and transition of care services. The transition from pediatric to adult care (ages 16-21) is a critical period with significant risk of loss to follow-up.
<image>Multidisciplinary ACHD center model showing the core team members and their roles including ACHD cardiologist, congenital surgeon, EP, heart failure, MFM, hepatology, and psychosocial support</image>
Clinical Pearls
More adults than children are now living with CHD, and the CT surgeon must be prepared to manage these patients. Every ACHD reoperative case requires a detailed preoperative CT scan to map retrosternal structures -- blind reentry is dangerous. Peripheral cannulation should be set up before reoperative sternotomy in any patient with structures adherent to the posterior sternum. Arrhythmias are the number one driver of ACHD emergency department visits, and understanding their hemodynamic impact in these patients is critical. Pregnancy counseling should occur before conception because Eisenmenger syndrome carries a maternal mortality of 30-50% during pregnancy. ACHD patients are frequently lost to follow-up during the transition from pediatric to adult care, and this gap is associated with preventable morbidity and mortality. Heart transplantation for ACHD is technically challenging but feasible at experienced centers, and early referral is key.
References
- Stout KK et al. "2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease." Circulation. 2019.
- Baumgartner H et al. "2020 ESC Guidelines for the management of adult congenital heart disease." Eur Heart J. 2021.
- Marelli AJ et al. "Lifetime prevalence of congenital heart disease in the general population." Circulation. 2014.
- Khairy P et al. "Arrhythmias in adult congenital heart disease." Expert Rev Cardiovasc Ther. 2006.
- Lui GK et al. "Diagnosis and management of noncardiac complications in adults with congenital heart disease." Circulation. 2017.
- Regitz-Zagrosek V et al. "2018 ESC Guidelines for the management of cardiovascular diseases during pregnancy." Eur Heart J. 2018.
