Response variability to aspirin and one-year prediction of vascular events in patients with stable coronary artery disease.

The aim of this study was to assess the association between "aspirin non responsiveness" in patients with coronary artery diseases (CAD) and the risk of major adverse cardiovascular events (MACE). 204 patients with CAD receiving aspirin (250 mg/d) were included. Both Collagen/Epinephrine Closure Time (CEPI-CT) and urinary Thromboxane B2 (uTxB2) concentration was used to determine the patients aspirin responsiveness. The clinical primary endpoint was the occurrence of MACE including: cardiovascular death, MI, stroke or transient ischemic attack. The secondary endpoint was the occurrence of Recurrent Acute Vascular Event (RAVE: MI, stroke or transient ischemic attack). After 1-year follow-up, no responders diagnosed by CEPI-CT had a trend for higher risk of MACE (13% vs 7.4%; P = 0.22) and significant higher risk of RAVE (OR = 2.1; 95%CI: 1.7-2.4; P = 0.01) when compared to good responders. Multivariate analysis showed that CEPI-CT < 143 s was the only independent predictor of RAVE (OR = 6.3; 95% CI: 1.2-32.2; P = 0.026). Aspirin non-responsiveness, diagnosed by the uTxB2, was not associated with an increased risk of either MACE or RAVE. Our results, reinforce the importance of being able to diagnose laboratory "aspirin non responsiveness", and extend the evidence that aspirin non responsiveness may explain in part the occurrence of RAVE.