Platelet reactivity and cardiovascular outcomes after percutaneous coronary intervention: A time-dependent analysis of the gauging responsiveness with a verifynow P2Y12 assay: Impact on thrombosis and safety (GRAVITAS) trial
BACKGROUND-: In the Gauging Responsiveness With A VerifyNow P2Y12 Assay: Impact on Thrombosis and Safety (GRAVITAS) trial, 6 months of high-dose clopidogrel did not reduce cardiovascular events compared with standard-dose clopidogrel in patients with high on-treatment platelet reactivity (OTR) after percutaneous coronary intervention, defined as OTR ≥230 P2Y12 reaction units according to the VerifyNow P2Y12 platelet function test. The aim of this analysis was to examine the relationship between outcomes and OTR over the course of the trial. METHODS AND RESULTS-: OTR was measured at 12 to 24 hours and 30±7 days after percutaneous coronary intervention. Cox proportional hazards models with OTR as a time-varying covariate were used to determine the association between OTR and the primary end point of cardiovascular death, myocardial infarction, and stent thrombosis. Of the 2800 enrolled patients, 2796 (99.98%) had evaluable platelet function data. OTR (hazard ratio, 0.18; 95% confidence interval, 0.04 to 0.79; P=0.02) and at 6 months (hazard ratio, 0.43; 95% confidence interval, 0.23 to 0.82; P=0.01). After adjustment for other significant predictors of outcome, OTR (hazard ratio, 0.23; 95% confidence interval, 0.05 to 0.98; P=0.047) and tended to be associated at 6 months (adjusted hazard ratio, 0.54; 95% confidence interval, 0.28 to 1.04; P=0.065). CONCLUSIONS-: In the GRAVITAS trial, achievement of on-clopidogrel reactivity © 2011 American Heart Association, Inc.
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School of Medicine
General Internal Medicine