What is the management and treatment of endocardial cushion defects?

Management and Treatment of Endocardial Cushion Defects

The management of endocardial cushion defects (ECDs) requires surgical correction for most patients, with timing based on symptom severity, hemodynamic effects, and presence of pulmonary hypertension. 1

Understanding Endocardial Cushion Defects

Endocardial cushion defects, also known as atrioventricular (AV) canal defects or AV septal defects (AVSD), are characterized by:

• A common AV annulus with five leaflets
• Defects at the crux of the heart that may extend into both atrial and ventricular septa
• Abnormal AV valve function (often with regurgitation)
• Abnormal cardiac conduction system positioning

These defects account for approximately 3% of all congenital heart defects, with 35% occurring in patients with Down syndrome 1. They can be classified as:

• Partial AVSD: Defect only at the atrial level (primum ASD)
• Complete AVSD: Defect extending into both atrial and ventricular septa

Diagnostic Evaluation

Initial evaluation should include:

• Echocardiography: Primary diagnostic tool to assess defect anatomy, valve function, chamber sizes, and pulmonary pressures
• Electrocardiogram: Often shows superior left-axis deviation with a counterclockwise loop in the frontal plane and first-degree AV block 1
• Chest X-ray: May show cardiomegaly and increased pulmonary vascular markings
• CMR (Cardiac Magnetic Resonance): Indicated when additional quantification of ventricular volumes, function, or intracardiac shunting is needed 1

Treatment Approach

Surgical Management

1. Indications for Surgery:

   • Complete AVSD: Early surgical repair is indicated to prevent development of pulmonary vascular disease
   • Partial AVSD: Surgical closure indicated for significant left-to-right shunting
   • Surgery must be avoided in patients with Eisenmenger physiology (irreversible pulmonary hypertension) 1

2. Surgical Techniques:

   • Patch closure of septal defects
   • Reconstruction of AV valves
   • Timing typically within the first 6 months of life for complete AVSD to prevent pulmonary hypertension

Medical Management

Medical management is primarily supportive while awaiting surgery or for patients with inoperable conditions:

• Heart failure management with diuretics and afterload reduction
• Treatment of arrhythmias if present
• Prevention and treatment of respiratory infections
• Nutritional support to promote growth in infants
• Endocarditis prophylaxis for high-risk patients 1

Special Considerations

Pulmonary Hypertension

• Regular assessment of pulmonary artery pressure is essential
• Patients who develop Eisenmenger syndrome have contraindications to pregnancy and should limit themselves to low-intensity activities 1
• Pulmonary vasodilator therapy may be considered in selected cases

Conduction Abnormalities

• Complete AV block may develop before or after surgical repair
• Patients who develop bifascicular block or transient trifascicular block after repair are at risk for later development of complete AV block 1
• Permanent pacing may be required for symptomatic bradycardia or high-risk conduction abnormalities 1

Pregnancy Considerations

• Pregnancy is contraindicated in patients with Eisenmenger syndrome due to high maternal and fetal mortality 1
• Women with repaired defects, normal ventricular function, and no pulmonary hypertension generally tolerate pregnancy well
• The recurrence risk of congenital heart disease has been reported at 6-10% 1

Follow-up Recommendations

• Lifelong regular follow-up of all patients (operated and unoperated) is recommended 1

• Evaluation in specialized Adult Congenital Heart Disease (ACHD) centers

• Particular attention to:

  • Residual shunts
  • AV valve function
  • Ventricular enlargement and dysfunction
  • Pulmonary artery pressure
  • Development of subaortic stenosis
  • Arrhythmias

• Frequency of follow-up:

  • Patients with residual abnormalities: More frequent follow-up
  • Surgically repaired AVSD without significant residual abnormalities: At least every 2-3 years 1

Indications for Reoperation

Indications for reoperation for residual abnormalities are comparable to those for primary surgery, including:

• Significant residual shunts
• Significant AV valve regurgitation
• Left ventricular outflow tract obstruction

Activity Recommendations

• Patients with repaired defects, normal ventricular function, and no pulmonary hypertension: No activity restrictions
• Patients with pulmonary hypertension: Limited to low-intensity recreational activities 1

Endocarditis Prophylaxis

Endocarditis prophylaxis is recommended only for high-risk patients according to current guidelines 1.