Antithrombotic Therapy With or Without Aspirin After Percutaneous Coronary Intervention or Acute Coronary Syndrome in Patients Taking Oral Anticoagulation: A Meta-Analysis and Network Analysis of Randomized Controlled Trials

Introduction: Trials investigating aspirin omission in patients taking oral anticoagulation (OAC) after percutaneous coronary intervention (PCI) or acute coronary syndrome (ACS) were not powered to assess rates of major bleeding or ischemic events.Methods: We performed an updated meta-analysis and network analysis of randomized trials comparing treatment with or without aspirin in patients taking OAC and a P2Y12-inhibitor after PCI or ACS. The primary outcome was TIMI major bleeding.Results: Five trials enrolling 11,542 patients allocated to antithrombotic regimens omitting (n = 5795) or including aspirin (n = 5747) were included. Aspirin omission was associated with a lower risk of TIMI major bleeding (RR = 0.56, 95% CI [0.44-0.71]; P < 0.001) but a trend towards a higher risk of MI (RR = 1.21, 95% CI [0.99-1.47]; P = 0.06), which was significantly higher when only non-vitamin K antagonist OAC (NOAC)-based trials were considered (Pinteraction = 0.02). The risk of stent thrombosis was comparable with both strategies (RR = 1.29, 95% CI [0.87-1.90]; P = 0.20), with a trend towards a higher risk of ST with aspirin omission when only NOAC-based trials were considered (Pinteraction = 0.06). Risks of stroke and death were similar with both strategies. Network meta-analysis ranked dabigatran (low dose) without aspirin as the best strategy for bleeding reduction (P-score = 0.86) and apixaban with aspirin as the best strategy for MI reduction (P-score = 0.66).Conclusions: In patients taking OAC after PCI or ACS, aspirin omission is associated with a lower risk of TIMI major bleeding, with a numerically increased risk of MI, which is statistically significant when only NOAC-based trials are considered. This supports individualization of the treatment regimen based on patient risk.