Is antiplatelet therapy (Antiplatelet agents) necessary after device closure of Atrial Septal Defect (ASD) or Ventricular Septal Defect (VSD)?

Antiplatelet Therapy After Device Closure of ASD and VSD

Yes, antiplatelet therapy is required after device closure of both ASD and VSD, with low-dose aspirin (100 mg daily minimum) for at least 6 months being the standard of care. 1

For ASD Device Closure

Mandatory Antiplatelet Regimen

Children should receive oral antiplatelet therapy with low-dose aspirin for at least 6 months after implantation (Class I, Level of Evidence C). 1

• The European Society of Cardiology guidelines specify antiplatelet therapy is required for at least 6 months with aspirin 100 mg daily minimum after device closure. 1
• All patients undergoing device closure should receive at least 100 U/kg UFH (up to 5000-U maximum dose) at the time of implantation (Class I, Level of Evidence C). 1

Age-Specific Considerations

• For older children and adults, another anticoagulant may be considered in addition to aspirin for 3 to 6 months after implantation (Class IIb, Level of Evidence C). 1
• Some centers use a combination of aspirin and clopidogrel (75 mg) initially for a variable duration followed by aspirin to complete a total of 6 months in adults or older patients. 1
• Aspirin therapy is often initiated 1 to several days before device implantation. 1

Evidence Supporting Single vs. Dual Antiplatelet Therapy

• A large retrospective cohort of 734 patients followed for a mean of 10.3 years demonstrated that 100 mg aspirin for 6 months resulted in device thrombosis rates of 0% for ASD and 0.2% for PFO, with no major bleeding events. 2
• A randomized study of 130 patients found no significant difference in safety or efficacy between aspirin alone versus aspirin plus clopidogrel, with no thromboembolic events or major bleeding in either group. 3
• A study of 37 patients using dual antiplatelet therapy (clopidogrel and aspirin) for 6 months showed no thrombus formation on transesophageal echocardiography. 4

For VSD Device Closure

Mandatory Antiplatelet Regimen

It is reasonable to treat children undergoing device closure of ventricular septal defects with oral antiplatelet therapy with low-dose aspirin for at least 6 months after implantation (Class IIa, Level of Evidence C). 1

• Children undergoing device closure of VSDs should receive UFH 100 U/kg (up to 5000-U maximum dose) at the time of implantation (Class I, Level of Evidence C). 1
• Patients undergoing device closure systematically receive 100 U/kg UFH intravenously at implantation and are discharged on an antiplatelet agent such as low-dose aspirin for 6 months. 1

Supporting Evidence

• Among multiple published series on transcatheter closure of ventricular septal defects, device-related thrombosis has not been reported as a procedural complication when aspirin therapy for 6 months is used. 1
• The common practice of using aspirin therapy for 6 months appears to be effective thromboprophylaxis, although no studies have directly addressed the safety and efficacy of aspirin in this specific population. 1

Rationale for Antiplatelet Therapy

Mechanism and Duration

• The duration of thromboprophylaxis theoretically should extend until complete device endothelialization is achieved, which is the basis for the standard 6-month duration. 1
• When 6-month aspirin prophylaxis is used in pediatrics, device thrombosis continues to be an extremely rare event. 1
• Platelet activation and aggregation rates are significantly increased immediately after ASD/VSD occlusion, with aspirin treatment (3-5 mg/kg/day) inducing significant decreases in platelet aggregation. 5

Special Circumstances Requiring Extended Therapy

If complete defect closure is not achieved (residual defect after device implantation), many elect to continue thromboprophylaxis beyond 6 months because there is an ongoing risk of paradoxical embolus. 1

• Complete endothelialization may not occur when residual shunting persists. 1
• In the large retrospective cohort, 10 patients (1.36%) with persistent moderate shunt at 12 months maintained aspirin 100 mg lifelong. 2

High-Risk Patient Considerations

• In higher-risk patients such as those with a history of stroke, inherited thrombophilic disorders should be excluded before device implantation so that antithrombotic prophylaxis can be adapted accordingly. 1
• Four patients in atrial fibrillation in one study were also anticoagulated (international normalized ratio 2.0 to 3.0) in addition to antiplatelet therapy. 4

Critical Pitfalls to Avoid

• Do not omit antiplatelet therapy entirely, as this is standard of care despite the extremely low incidence of device thrombosis. 1
• Do not routinely use dual antiplatelet therapy in children, as single-agent aspirin is equally effective and safer. 3
• Do not discontinue aspirin before 6 months unless there are compelling contraindications, as complete endothelialization requires this duration. 1
• Do not forget procedural anticoagulation with UFH at the time of device implantation, which is a Class I recommendation. 1
• Do not continue aspirin indefinitely in all patients—only those with residual shunting require extended therapy beyond 6 months. 1, 2