Early but not late stent thrombosis is influenced by residual platelet aggregation in patients undergoing coronary interventions

Aims Recent studies suggest a relevant association of post-interventional. residual platelet aggregation (RPA) under therapy with oral platelet inhibitors and the occurrence of atherothrombotic events. The influence of post-interventional RPA on the incidence of stent thrombosis (ST) has not been sufficiently evaluated in consecutive unselected cohorts of percutaneous coronary intervention (PCI) patients. The aim of this observational study was to investigate the impact of RPA on the incidence of ST within 3 months in patients treated with dual antiplatelet therapy. Methods and results The study population included a consecutive cohort of 1019 patients treated with PCI [n = 741 bare-metal stent (BMS) and n = 278 drug-eluting stent (DES)] due to symptomatic coronary artery disease. Residual platelet activity was assessed by adenosine disphosphate (20 mu mol/L)-induced PA after 600 mg clopidogrel loading dose. Maximum RPA was measured as peak of aggregation, final RPA was measured 5 min after addition of agonist. The primary end-point was the occurrence of ST within 3 months defined according to academic research consortium (ARC) criteria. Final and maximum RPA were independent predictors of ST after 3 months. In secondary analysis, the observed effects were independently associated with early ST (HR 1.05, 95% CI 1.01 - 1.08 and HR 1.05, 95% CI 1.01 - 1.09, P < 0.01, respectively). However, incidence of 3-month late stent thrombosis (LAT) was not influenced by post-interventional RPA in multivariable analysis. Conclusion Post-interventional RPA is associated with the occurrence of early ST in patients treated with either BMS or DES; however, there is no predictive value of RPA for the incidence of 3-month LAT, suggesting the involvement of other possible mechanisms like discontinuation of antiplatelet therapy.