Platelet Aggregometry as a Marker of Risk for Vascular Events: Not Yet

Aspirin plays an important role in stroke prevention, but many patients have recurrent events despite taking it. There is growing interest, therefore, in laboratory tests of effectiveness of aspirin that might be used to target patients for higher doses or for changing to alternative agents. In this study, investigators retrospectively assessed 241 patients referred for platelet aggregometry. All participants had histories of at least one clinical vascular event (stroke, TIA, myocardial infarction, or unstable angina) within the past 5 years and had been taking aspirin for at least 30 days (about half for at least 1 year). To ascertain the outcome — a clinical history of recurrent vascular events during the 5-year interval — the investigato…