Atrial Septal Defect (ASD) Closure — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

An atrial septal defect (ASD) is a congenital hole in the interatrial septum, the wall dividing the heart's two upper chambers (atria). It allows oxygenated blood returning from the lungs to mix with deoxygenated blood, creating a left-to-right shunt that volume-overloads the right ventricle and pulmonary circulation. Over years, untreated significant ASDs lead to right heart enlargement, atrial arrhythmias, pulmonary hypertension, and reduced exercise tolerance. ASD closure eliminates the shunt, allowing the right heart to normalise in size and function. The procedure can be performed by two methods: transcatheter closure, in which a collapsible occluder device is delivered via a catheter through the femoral vein without surgery; and open-heart surgery under cardiopulmonary bypass, which provides access to all ASD types. Transcatheter closure with devices such as the Amplatzer Septal Occluder is now the preferred technique for secundum-type ASDs with adequate tissue rims around the defect — the most common type, accounting for approximately 70% of all ASDs. The procedure is performed by interventional cardiologists or paediatric cardiac surgeons depending on the patient's age and ASD anatomy. An atrial septal defect (ASD) is a congenital hole in the interatrial septum, the wall dividing the heart's two upper chambers (atria). This allows left-to-right shunting of oxygenated blood, creating a volume load on the right heart, pulmonary vasculature, and eventually causing right heart dilatation, arrhythmias, and — if untreated — pulmonary arterial hypertension. ASD is one of the most common congenital heart defects, affecting approximately 1 in 1,500 live births. Closure is performed by paediatric cardiologists, adult congenital heart disease specialists, or cardiac surgeons depending on the defect anatomy and patient age. Transcatheter closure using an Amplatzer or similar self-expanding occluder device is now standard for secundum ASDs with adequate septal rims.

ASD closure is indicated when the defect is haemodynamically significant, meaning it causes right heart enlargement (right ventricular volume overload with a ratio of pulmonary-to-systemic blood flow [Qp:Qs] greater than 1.5:1), exercise intolerance, atrial arrhythmias, paradoxical embolism, or when echocardiography demonstrates progressive right ventricular dilatation. In children, intervention is typically recommended between the ages of two and five years before school age to prevent long-term sequelae. In adults, closure is beneficial even in middle age provided pulmonary vascular resistance has not become severely elevated (irreversible pulmonary hypertension is a contraindication). Small ASDs (less than 5 mm) without haemodynamic significance may be observed without closure. Secundum ASDs with adequate rims (greater than 5 mm from the atrioventricular valves, coronary sinus, and superior vena cava) are suitable for transcatheter closure. Sinus venosus, primum, and coronary sinus ASDs require surgical repair because their anatomy does not support device deployment. Patients with symptomatic cryptogenic stroke attributable to paradoxical embolism through a patent foramen ovale — a related but distinct entity — may also undergo percutaneous closure.

Transcatheter ASD closure is performed in a cardiac catheterisation laboratory under general anaesthesia or deep sedation with continuous transoesophageal or intracardiac echocardiography and fluoroscopy guidance. A venous sheath is inserted into the femoral vein. A catheter is advanced through the sheath, across the inferior vena cava, into the right atrium, and then through the ASD into the left atrium. A sizing balloon is inflated across the defect to measure the stretched diameter and confirm rim adequacy. The appropriately sized Amplatzer Septal Occluder (available in sizes 4–38 mm) is loaded onto a delivery cable and advanced through the sheath. The left atrial disc is deployed first, pulled back against the septum, then the right atrial disc is deployed, sandwiching the septal tissue. Correct position is confirmed by echocardiography and fluoroscopy before the device is released. The entire transcatheter procedure takes sixty to ninety minutes. Open surgical repair is performed via median sternotomy or minimally invasive right anterolateral thoracotomy under cardiopulmonary bypass. The ASD is closed with direct suture or a pericardial or synthetic patch. Bypass time averages forty-five to ninety minutes. Transcatheter ASD closure is performed in a cardiac catheterisation laboratory under general anaesthesia or deep sedation with continuous transoesophageal echocardiography (TEE) and fluoroscopic guidance. The shunt measurement confirms eligibility, the occluder is deployed under real-time imaging guidance, and correct position and adequate residual rim confirmed before device release. Post-deployment, the device is re-examined with echocardiography for correct position, residual shunt, and absence of impingement on adjacent cardiac structures including the AV node and pulmonary veins. The sheath is removed, haemostasis achieved, and the patient transferred to the cardiology ward for 24-hour monitoring.

Successful ASD closure produces significant and measurable cardiac benefits within months of the procedure. Right ventricular volumes normalise in the majority of patients, with right ventricular end-diastolic diameter reducing by thirty to forty percent at six-month echocardiography. Exercise capacity measured by cardiopulmonary exercise testing improves significantly compared to baseline, particularly in patients with pre-procedural right ventricular dysfunction. Atrial arrhythmias — most commonly atrial fibrillation and flutter — may partially improve after closure, particularly when performed before the age of forty years; in older patients existing arrhythmias often require additional treatment. Transcatheter device closure achieves complete shunt elimination in over ninety-five percent of cases at twelve-month follow-up with the Amplatzer device, comparable to surgical repair. Quality of life scores improve significantly. The transcatheter approach avoids sternotomy, cardiopulmonary bypass, blood transfusion, and intensive care admission, with patients typically discharged within twenty-four to forty-eight hours. Long-term survival after closure in adults is comparable to age-matched general population controls when performed before pulmonary hypertension becomes irreversible.

Transcatheter ASD closure is a safe procedure with major complication rates below two percent at experienced centres. Device-related complications include device embolisation requiring retrieval (less than one percent), device erosion into the aorta or pericardium causing haemopericardium (a rare but serious late complication occurring in approximately 0.1–0.3% of implants, more common with oversized devices), residual shunt requiring further intervention, and atrial arrhythmias related to device placement. Vascular access complications include haematoma and arteriovenous fistula at the femoral puncture site. Air embolism and thrombus formation on the device are rare with appropriate anticoagulation. In the six to twelve weeks before device endothelialisation is complete, patients take aspirin 75–150 mg daily with or without clopidogrel, and antibiotic prophylaxis may be recommended for dental procedures. Surgical repair carries general anaesthetic, sternotomy, and bypass-related risks including bleeding requiring reoperation (approximately one to two percent), wound infection (one percent), and postpericardiotomy syndrome. Pulmonary vascular disease is a contraindication — closure in established severe irreversible pulmonary hypertension can cause acute right heart failure and is harmful.

After transcatheter ASD closure, patients are observed in hospital for twenty-four to forty-eight hours with continuous cardiac monitoring. Discharge medications include aspirin for six months (to prevent thrombus on the device before endothelialisation) and sometimes clopidogrel for one to three months. Patients are advised to avoid strenuous exercise for two to four weeks and to refrain from contact sports or heavy lifting for four to six weeks. Echocardiography follow-up is performed at one, three, six, and twelve months to confirm device position, assess residual shunting, and document right ventricular remodelling. Antibiotic prophylaxis against infective endocarditis is recommended for six months after device implantation. After surgical repair, hospital discharge occurs at three to five days, with return to light activities at two weeks and full activity at four to six weeks. Sternotomy precautions (avoiding lifting greater than five kilograms, no driving for four to six weeks) apply to surgical patients. Annual echocardiographic surveillance is recommended for five years post-closure to monitor for late complications and confirm sustained normalisation of right heart dimensions.