Congenital Heart Defects in Adults (ACHD)

Epidemiology

• Bicuspid aortic valve: ~2% of the general population; the single most common congenital cardiac anomaly in adults and up to 50% of surgical aortic stenosis cases
• ASD: 30-40% of all ACHD; ostium secundum ASD = 7% of all congenital lesions
• VSD: 15-20% of all congenital lesions (most common in children; high spontaneous closure rates explain lesser adult prevalence)
• PDA: 5-10% of all congenital cardiac lesions in infants
• Pulmonary stenosis / coarctation: 3-10% each
• Tetralogy of Fallot: the most common cyanotic congenital anomaly in adults

Classification

I. By Shunt Direction / Physiology

II. By Anatomic Complexity (ACC/AHA)

III. Anatomic and Physiologic (AP) Classification (Modern)

• Anatomic dimension: Segmental approach (situs, connections, ventricular morphology) + IPCCC/ICD-11 coding
• Physiologic dimension (A-D): Grade A (NYHA I, no sequelae) through Grade D (NYHA IV, severe hypoxemia, Eisenmenger, refractory end-organ dysfunction)

Etiology

Genetic Causes (~20% of cases)

• Down syndrome (Trisomy 21): ~50% have endocardial cushion defects and VSD
• Trisomy 13 and 18: VSD in 90%
• Turner syndrome (45,X): Aortic coarctation, aortic stenosis, ASD
• 22q11.2 deletion (DiGeorge / CATCH-22 syndrome): TOF (15%), interrupted aortic arch, truncus arteriosus - shared features: Cardiac defects, Abnormal facies, Thymic hypoplasia, Cleft palate, Hypocalcemia
• Williams syndrome (7q11.23): Supravalvular aortic stenosis
• Noonan syndrome (12q22): Pulmonary stenosis, ASD, hypertrophic cardiomyopathy
• Holt-Oram syndrome (autosomal dominant): ASD + skeletal anomalies
• Marfan syndrome: Aortic root dilation, mitral valve prolapse

Familial / Recurrence Risk

• Mother carrying a sporadic lesion: 2.5-18% recurrence risk (obstructive LVOT lesions highest)
• Father carrying the lesion: 1.5-3%
• Sibling with CHD: 1-3% risk to next sibling

Environmental / Teratogenic Factors

• Maternal rubella infection (PDA, pulmonary stenosis)
• Maternal diabetes (TGA, VSD, coarctation)
• Maternal alcohol use (VSD, ASD)
• Thalidomide, phenytoin, retinoic acid
• Maternal lupus (congenital heart block)

Pathophysiology

1. Left-to-Right Shunts (Acyanotic)

• Pulmonary overcirculation → reactive pulmonary vasoconstriction
• Progressive pulmonary arterial hypertension (PAH)
• Eventually, shunt reversal = Eisenmenger syndrome (right-to-left shunt, late cyanosis)

• ASD: Right atrial and RV volume overload; RV dilates. Large ASD eventually causes RV failure and atrial arrhythmias. Risk of paradoxical embolism (even before Eisenmenger)
• VSD: LV and RV volume overload; pulmonary hypertension develops earlier than in ASD (post-tricuspid shunt). Small VSDs may close spontaneously
• PDA: Aorta-to-pulmonary artery communication; left heart volume overload. Continuous "machinery" murmur

2. Right-to-Left Shunts (Cyanotic)

• Secondary erythrocytosis
• Iron deficiency
• Hyperviscosity
• Paradoxical embolism and cerebrovascular accidents
• Hemoptysis (from pulmonary arteriopathy)

3. Obstructive Lesions

• Pulmonary stenosis: RV pressure overload → RVH → eventual RV failure
• Aortic stenosis: LV pressure overload → LVH → diastolic dysfunction → systolic failure
• Coarctation of the aorta: Proximal hypertension (risk of aortic dissection, rupture, LVH); distal hypoperfusion and collateral formation

4. Complex Lesions

• Transposition of the great arteries (D-TGA): Parallel rather than series circulations; incompatible with life without mixing (ASD/VSD/PDA). Post-atrial switch (Mustard/Senning) operations: systemic RV is at high risk for progressive failure
• Congenitally corrected TGA (CC-TGA): Morphologic RV supports systemic circulation; progressive RV failure + complete heart block are common
• Single ventricle / Fontan circulation: Passive pulmonary blood flow without a subpulmonary ventricle; systemic venous hypertension, protein-losing enteropathy, arrhythmias, liver fibrosis

Clinical Signs and Symptoms

Symptoms (by category)

Key Physical Signs

• Central cyanosis (lips, tongue, nailbeds) - right-to-left shunts
• Digital clubbing - chronic hypoxemia (TOF, Eisenmenger)
• Differential cyanosis (lower body cyanotic, upper normal) - PDA with Eisenmenger physiology

• Central cyanosis and digital clubbing
• Prominent jugular venous a-wave
• Right parasternal heave/lift
• Loud P2
• S3 or S4
• Diastolic murmur of pulmonary regurgitation
• Systolic murmurs may be faint or absent (low-pressure shunt)

Diagnosis

History and Algorithm (Goldman-Cecil Medicine)

1. What is the native anatomy?
2. Has the patient had surgery for the condition?
3. What are the residual hemodynamic sequelae?

Investigations

• ASD: Right axis deviation, incomplete RBBB, right atrial enlargement; ostium primum → left axis deviation
• VSD: LVH (large VSD), biventricular hypertrophy
• TOF (unrepaired): Right axis deviation, dominant RV forces; post-repair: complete RBBB (80-90%)
• Pulmonary stenosis: Right axis deviation, peaked P waves, R > S in V1 with severe stenosis
• Eisenmenger: Right atrial enlargement, right axis deviation, biventricular hypertrophy, ST-T changes

• ASD: Cardiomegaly, prominent pulmonary artery, increased pulmonary vascular markings
• VSD: Biventricular enlargement, pulmonary plethora
• TOF: Boot-shaped heart (coeur en sabot) - upturned apex with concave pulmonary artery segment
• Coarctation: Rib notching (collateral vessels), "3-sign" on aortic knob, "E-sign" on barium swallow
• Eisenmenger: Dilated central pulmonary arteries with peripheral "pruning," RV enlargement

• Transthoracic echo (TTE): Identifies anatomy, shunts (color Doppler), pressure gradients, ventricular function
• Transesophageal echo (TEE): Better definition of ASD morphology, valves, pulmonary veins
• In Eisenmenger: RV enlargement/hypertrophy, pulmonary artery enlargement, low-velocity flow through shunt

• Gold standard for quantifying RV volumes and function (critical in TOF post-repair)
• Accurately documents distal pulmonary artery stenosis
• Aortic imaging in coarctation and Marfan syndrome

• Reserved for pre-operative/pre-interventional planning
• Measures pulmonary vascular resistance (critical in Eisenmenger)
• Coronary angiography when indicated

• CBC: Erythrocytosis in cyanotic CHD, thrombocytopenia in Eisenmenger
• Iron studies: Iron deficiency is common in erythrocytosis (impairs RBC function)
• BNP/NT-proBNP: Heart failure marker
• Uric acid: Elevated in Eisenmenger (hyperuricemia)

Differential Diagnosis

Treatment

General Principles

Specific Lesion Management

Atrial Septal Defect (ASD)

• Indications for closure: Significant shunt (Qp:Qs ≥1.5:1) with evidence of RV volume overload, or paradoxical embolism. NOT indicated if severe, irreversible pulmonary hypertension (PVR >2/3 systemic)
• Percutaneous device closure: Treatment of choice for ostium secundum ASD with adequate rims; Amplatzer or similar occluder devices
• Surgical closure: For sinus venosus, primum, or coronary sinus ASDs; when device closure not feasible
• Post-procedure: Aspirin for 6 months; endocarditis prophylaxis per guidelines; surveillance for atrial arrhythmias

Ventricular Septal Defect (VSD)

• Small, restrictive VSDs: Annual monitoring; no closure required
• Indications for closure: LV volume overload, prior infective endocarditis, or progressive aortic regurgitation
• Percutaneous or surgical closure depending on location (muscular vs. perimembranous)

Patent Ductus Arteriosus (PDA)

• Closure recommended for any hemodynamically significant PDA
• Percutaneous coil or device occlusion for most
• Surgical ligation for large or complicated PDAs

Pulmonary Stenosis

• Intervention threshold: Mean Doppler gradient ≥30 mmHg + symptoms (or ≥40 mmHg regardless of symptoms) unless moderate/severe pulmonary regurgitation
• Percutaneous balloon valvotomy: Procedure of choice for doming valve; excellent long-term results (>95% 25-year survival)
• Transcatheter pulmonary valve replacement: When valvuloplasty fails or not possible
• Surgical resection: For subvalvular stenosis (double-chambered RV)

Aortic Stenosis (Bicuspid/Congenital)

• Follow guidelines similar to acquired aortic stenosis for intervention thresholds
• TAVR increasingly used; surgical AVR for those unsuitable for transcatheter approach
• Annual surveillance of the aorta is mandatory given bicuspid valve-associated aortopathy

Coarctation of the Aorta

• Intervention: Gradient ≥20 mmHg arm-to-leg at rest, or hypertension with radiological evidence of significant coarctation
• Percutaneous stenting: First-line for most adults (vs. surgical repair in children)
• Balloon angioplasty alone carries risk of re-coarctation and aneurysm
• Lifelong surveillance for hypertension, re-coarctation, and aortic aneurysm

Tetralogy of Fallot

• After childhood repair, ongoing surveillance is mandatory (yearly ACHD specialist review)
• Pulmonary valve replacement (PVR): Indicated when RV pressure >2/3 systemic due to residual RVOTO, or free pulmonary regurgitation with RV dysfunction. ICD should be considered concurrently if arrhythmia burden is high
• Monitor for: Residual PS, pulmonary regurgitation, residual VSD, arrhythmias (atrial flutter, VT), and sudden cardiac death (3-6% over 20-30 years)
• Cardiac MRI is essential for RV volume and function monitoring

Transposition of the Great Arteries (post-Mustard/Senning)

• Systemic right ventricle is at high risk for failure - monitor with MRI and BNP
• Arrhythmia surveillance (sinus node dysfunction, atrial flutter common)
• Heart failure therapy (ACE inhibitors, beta-blockers); transplantation may be needed

Eisenmenger Syndrome

• Contraindicated: Closure of the shunt (irreversible PAH); systemic vasodilators without PAH therapy; inappropriate phlebotomy; pregnancy
• Pulmonary arterial hypertension therapy: Endothelin receptor antagonists (bosentan - most evidence), phosphodiesterase-5 inhibitors (sildenafil), prostacyclin analogs
• Phlebotomy: Only if severe hyperviscosity symptoms AND hematocrit >65%; must replace volume isovolemically; NOT for erythrocytosis without symptoms
• Iron supplementation: Address iron deficiency carefully (may worsen erythrocytosis acutely)
• Anticoagulation: Not routinely recommended due to bleeding risk; consider for specific indications (intracardiac thrombus, atrial arrhythmias)
• Heart-lung transplantation: Definitive option in carefully selected patients
• Avoid: Dehydration, systemic vasodilators, nephrotoxins, air in IV lines (paradoxical embolism)

Infective Endocarditis Prophylaxis

• Complex cyanotic CHD (unrepaired or residual defects)
• Prosthetic cardiac valves or material
• Repaired CHD with prosthetic material within 6 months (until endothelialized)
• Repaired CHD with residual defects at or adjacent to prosthetic patch/device

Exercise Recommendations

Complications

Cardiovascular Complications

Hematologic Complications (Cyanotic/Eisenmenger)

Non-Cardiac Complications

• Renal dysfunction: Chronic reduced renal perfusion in Fontan, cyanotic CHD
• Liver disease / fibrosis: Chronic venous congestion in Fontan circulation; risk of hepatocellular carcinoma
• Protein-losing enteropathy: Fontan circulation (high systemic venous pressure → intestinal protein loss)
• Neurological: Stroke/TIA from paradoxical embolism, brain abscess (right-to-left shunt allows septic emboli to bypass pulmonary filter), cerebral hyperviscosity
• Pregnancy risks: Significantly elevated maternal and fetal mortality in Eisenmenger (maternal mortality 30-50%), Fontan, severe PAH, cyanotic CHD, systemic ventricular dysfunction
• Psychosocial: Depression, anxiety, employment, and insurance barriers are common; transition from pediatric to adult care is a critical vulnerability period

Prognosis

• Simple, repaired ACHD (ASD, small VSD, PS): Near-normal life expectancy
• Repaired TOF: 85% 30-year survival; risk of sudden cardiac death remains
• Eisenmenger syndrome: Death rare in childhood; becomes common after the 4th decade; worse prognosis with pre-tricuspid shunts, lower resting O2 saturations, non-sinus rhythm, and pericardial effusion
• Fontan/single ventricle: Progressive attrition; 5-year transplant-free survival approximately 70-80% at 20 years
• Post-Mustard/Senning (systemic RV): Progressive RV failure is a major long-term concern

• Goldman-Cecil Medicine International Edition, Ch. 55 (CONGENITAL HEART DISEASE IN ADULTS)
• Fuster and Hurst's The Heart, 15th Edition, Chs. 65-70 (Adult Congenital Heart Disease section)
• Braunwald's Heart Disease, Ch. 82 (Eisenmenger syndrome)
• 2025 ACC/AHA/HRS/ISACHD/SCAI Guideline for the Management of Adults With Congenital Heart Disease - PMID 41411480 - the most current practice guideline (published February 2026 in JACC and Circulation)

Note: The 2025 ACC/AHA guideline (PMID 41411480) represents a major update to prior recommendations and should be consulted for current class-of-recommendation / level-of-evidence specifics on interventional thresholds and surveillance intervals.