The impact of oral antiplatelet responsiveness on the long-term prognosis after coronary stenting.

Background: Decreased responsiveness to oral antiplatelet drug therapy has been associated with an adverse outcome after coronary stenting (CS), but more studies are needed. The purpose of the present study was to prospectively evaluate this issue.
Methods: A total of 612 consecutive patients with stable or unstable coronary artery disease who underwent CS after at least 12 hours of aspirin and clopidogrel loading were studied. The study population was divided into responders and nonresponders to oral antiplatelet therapy, according to the values of preprocedural Platelet Function Analyzer-100 (Dade Behring, Marburg, Germany) collagen epinephrine closure time (CEPI-CT). In particular, responders were considered as patients with a CEPI-CT > 193 seconds and nonresponders as those with a CEPI-CT < or = 193 seconds. The 1-year incidence of the composite of cardiac death and rehospitalization for nonfatal myocardial infarction was the prespecified primary study end point.
Results: At 1 year, 9.1% of patients reached the primary end point. Nonresponders to oral antiplatelet therapy were at significantly higher risk for the primary end point (18.7% vs 7.6%) than responders. Nonresponsiveness to oral antiplatelet therapy was a predictor of the primary end point by both univariate (hazard ratio 2.7, 95% CI 1.6-4.5, P < .001) and multivariate (hazard ratio 2.5, 95% CI 1.6-3.8, P < .001) Cox regression analysis.
Conclusion: Based on the present data, preprocedural responsiveness to oral antiplatelet therapy, assessed by Platelet Function Analyzer-100 CEPI-CT, is an independent predictor of long-term outcome after CS.