Abstract 870: A Randomized Pilot Trial for Aggressive Therapeutic Aapproaches in Aspirin Resistant Patients Undergoing Percutaneous Coronary Intervention
Aspirin (ASA) non responsiveness is associated with a higher incidence of ischemic events after percutaneous coronary intervention (PCI). The optimal antiplatelet therapy in ASA resistant pts undergoing PCI is unknown. We evaluated if aggressive antiplatelet therapy, especially the intraprocedural IIb/IIIa inhibitors and high maintenance dose of clopidogrel would reduce ischemic events in ASA non responsive pts.
Methods and Results: Verify Now -ASA assay( Accumetrics Inc.) was used to screen for ASA response in pts undergoing elective PCI. A total of 330 pts were screened for ASA responsiveness. 36 ASA non responsivene pts (aspirin reaction units >550) were randomized into 2 arms: Conventional Arm: Pts received 325 mg ASA orally and a loading dose of 600-mg Clopidogrel at the time of the procedure and ASA 325 mg, Clopidogrel 75 mg daily post procedure. Intraprocedurally, Bivalirudin 0.75 mg/kg IV bolus and 1.75 mg/kg/h IV infusion for 1 hr; Aggressive Arm: ASA, Clopidogrel and Bivalirudin use were similar to the conventional arm. In addition, IV GP IIb/IIIa inhibitor (1 bolus with Abciximab or 2 boluses with Eptifibatide) were used intra-procedurally followed by Clopidogrel 150 mg daily (for 1 mo) and then 75 mg daily and ASA 325 mg daily. Primary endpoint was a composite of major adverse cardiac events (MACE: Death, MI and urgent revascularization) and bleeding complications up to 30 days from the index procedure. Secondary endpoint was the incidence of post procedural creatine kinase (CK-MB) and Troponin (TnI) elevation above baseline within 24 hours of the procedure. The primary endpoint was reached in 5 pts (27%) in conventional and 1 pt (5.5%)in the aggressive arm (p=0.17) suggestive of a statistical trend towards more ischemic events with conventional therapy. Importantly, there were 2 definite stent thromboses in the conventional arm. Any periprocedural CK-MB and Tn-I release (<3× normal) was similar in both arms (n=2 in aggressive and n=1 in conventional arm); none had >3× normal.
Conclusions: Aggressive pre and postprocedural antiplatelet therapy is required in ASA nonresponsive pts. GP IIb/IIIa inhibitors and high maintenance dose of Clopidogrel may reduce the incidence of stent thrombosis. These findings need validation in a large randomized study.