Prasugrel Monotherapy After Percutaneous Coronary Intervention for Chronic Coronary Syndrome: Insights From ASET Pilot Studies

Background: The ASET (Acetyl-Salicylic Elimination Trial) pilot studies recently investigated P2Y₁₂ inhibitor monotherapy without aspirin immediately after percutaneous coronary intervention (PCI) in Brazil and Japan. Objectives: This comparative analysis of the 2 ASET pilot studies aimed to summarize clinical outcomes and assess geographic and ethnic differences in baseline demographics and procedures. Methods: Patients undergoing successful platinum-chromium everolimus-eluting stent implantation for chronic coronary syndrome were included. Following the index PCI, patients received prasugrel monotherapy with a maintenance dose of 10 mg/day in Brazil and 3.75 mg/day in Japan. The primary ischemic endpoint was the composite of cardiac death, spontaneous target vessel myocardial infarction, or definite stent thrombosis. The primary bleeding endpoint was Bleeding Academic Research Consortium types 3 and 5 bleeding at up to 3 months. Results: Of 409 enrollments, 3-month follow-up was completed in 406 patients. Mean age was 64.3 ± 8.4 years, and 73% were men. Overall, post-TIMI flow grade 3 was achieved in 99.8%. Intravascular imaging for poststent optimization was used in 16.8% and 99.6% of treated lesions in Brazil and Japan, respectively. The primary ischemic and bleeding endpoints occurred in the same patient (0.2%). No stent thrombosis events occurred. Conclusions: Prasugrel monotherapy following PCI was safe and feasible in selected low-risk chronic coronary syndrome patients after optimal platinum-chromium everolimus-eluting stent implantation regardless of the ethnic and geographic differences in baseline demographics, procedures, and prasugrel dosage. Randomized controlled trials will be needed to compare P2Y₁₂ inhibitor monotherapy without aspirin with the current standard of care.