Background: Previous studies have shown a significant association between endothelial dysfunction and CAD and cardiovascular risk factors. Since the endothelium is a systemic organ, endothelial dysfunction is a systemic vascular disorder which bring about a reduction in nitric oxide (NO) bioavailability accounting for distraction of the platelet function. Thus, we expect to find an association between platelet function and endothelial function assessed by the brachial artery FMD in healthy subjects and in CAD patients. Moreover, as platelet function, normally blocked by an effective anti-thrombotic therapy, is linked to the progression of atherosclerosis which, by itself is an influential process on endothelial function, we expect to find an association between endothelial function and the success of anti-thrombotic therapy.