Response to Letter Regarding Article, “Incomplete Inhibition of Thromboxane Biosynthesis by Acetylsalicylic Acid: Determinants and Effect on Cardiovascular Risk”

To the Editor: In their article about 3261 aspirin-treated patients enrolled in the Clopidogrel for the High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance (CHARISMA) trial,1 Eikelboom et al suggest that incomplete inhibition of platelet thromboxane biosynthesis by aspirin is associated with heightened cardiovascular risk on the basis of the finding that high urinary concentrations of the thromboxane A2 metabolite, 11-dehydrothromboxane B2, were associated with increased risk for cardiovascular events. Among the limitations of this study that have been acknowledged by the authors, the choice of urinary 11-dehydrothromboxane B2 …