Thromboxane Receptor Antagonist to Improve Endothelial Function

Thromboxane is a prostaglandin produced in healthy individuals mainly in platelets, where it mediates platelet activation and vasoconstriction via binding to cellular thromboxane-prostanoid (TP) receptors. The cardioprotective effect of aspirin is due to suppression of platelet thromboxane generation and reactivity. Unfortunately 25-50% of patients with cardiovascular disease taking ASA continue to generate thromboxane from non-platelet sources, which significantly increases their risk of atherothrombosis and death. Evidence suggests that oxidative stress is a potent stimulus for thromboxane generation in endothelial cells that involves autocrine/paracrine signaling through the TP receptor. This clinical trial addresses the central hypothesis that vascular endothelial cells under oxidative stress are a major source of non-platelet thromboxane generation in patients with cardiovascular disease and that antagonism of the TP receptor will suppress its formation and improve endothelial function.