Antiplatelet Therapy After ASD Closure
Yes, ASD closure absolutely requires antiplatelet therapy—specifically low-dose aspirin for at least 6 months after device implantation, which is a Class I recommendation with standard-of-care status. 1
Periprocedural Anticoagulation
At the time of device implantation, all patients must receive at least 100 U/kg unfractionated heparin (UFH) up to a 5000-U maximum dose (Class I, Level of Evidence C). 1 This is non-negotiable regardless of patient age or ASD type.
Post-Procedural Antiplatelet Regimen
Standard Therapy for Children
- Oral low-dose aspirin for at least 6 months after implantation (Class I, Level of Evidence C) 1
- The typical dosing is aspirin 5 mg/kg/day in pediatric patients 1
Standard Therapy for Adults
- Aspirin 100 mg daily minimum for at least 6 months 2
- For older children and adults, another anticoagulant may be considered in addition to aspirin for 3 to 6 months (Class IIb, Level of Evidence C) 1
- Some centers use combination therapy with aspirin plus clopidogrel 75 mg initially for variable duration, followed by aspirin alone to complete 6 months 1, 3
Evidence Supporting Single vs. Dual Antiplatelet Therapy
Recent research demonstrates that single antiplatelet therapy with aspirin alone is as safe and effective as dual antiplatelet therapy (aspirin plus clopidogrel) with no significant difference in thrombotic or bleeding complications 4. A large retrospective cohort of 734 patients showed that 100 mg aspirin for 6 months resulted in 0% device thrombosis in ASD patients with excellent safety profile (0.9% minor bleeding, 0% major bleeding) 5.
Rationale and Duration
The 6-month duration is based on the time required for complete device endothelialization. 1, 2 While limited human explantation data exist on this exact timeline, the standard-of-care 6-month duration has proven highly effective, with device thrombosis remaining an extremely rare event when this protocol is followed 1.
When to Extend Beyond 6 Months
If complete defect closure is not achieved (residual shunt after device implantation), continue thromboprophylaxis beyond 6 months due to ongoing risk of paradoxical embolus. 1, 2 In one study, 1.5% of patients with persistent moderate shunt at 12 months maintained aspirin lifelong 5.
High-Risk Patient Modifications
In patients with history of stroke or other high-risk features, screen for inherited thrombophilic disorders before device implantation to adapt antithrombotic prophylaxis accordingly. 1, 2, 3 This allows for individualized risk stratification and potentially more aggressive anticoagulation strategies.
Safety Profile
The safety data strongly supports this approach:
- Device thrombosis rates: 0-0.2% with standard aspirin therapy 5
- Cerebral ischemic events: 0.4% in large cohorts 5
- Major bleeding: 0% 5, 4
- Minor bleeding (ecchymosis): 4.6-6.1% 4
Biological Mechanism
Interestingly, transcatheter ASD closure primarily activates the coagulation system (elevated prothrombin fragment 1+2 levels peaking at 7 days) rather than the platelet system 6. This raises theoretical questions about whether anticoagulants might be superior to antiplatelets, but the clinical evidence overwhelmingly supports aspirin as safe and effective, making it the standard of care 6.
Critical Pitfalls to Avoid
- Never omit antiplatelet therapy entirely—this is standard of care despite extremely low device thrombosis incidence 2
- Never discontinue aspirin before 6 months unless compelling contraindications exist, as complete endothelialization requires this duration 2
- Never skip procedural UFH anticoagulation at device implantation—this is a Class I recommendation 2
- Never assume aspirin started after the procedure is sufficient—many centers initiate aspirin 1 to several days before device implantation 1
- Always perform follow-up transesophageal echocardiography within the first 4 weeks to detect early thrombus formation and extend antiplatelet therapy if needed 3