Using no language restrictions we s

Using no language restrictions we systematically searched for studies on antiplatelet therapy from 1966 to the present through Medline, Embase, CHINAHL, and the Cochrane Controlled Trials Registry. We used the search terms “acetylsalicylic acid”, “aspirin”, “antiplatelet”, “antiplatelets”, “platelets”, “drug resistance”, “aspirin resistance”, and “platelet resistance”. The initial search identified 36 573 papers. When we refined our search to aspirin resistance the number of papers was reduced to 320, and 210 remained when we further refined the search to aspirin resistance and clinical outcome. An expert hand searched and reviewed citations within these 210 key papers. We reviewed 268 abstracts for evidence of data related to aspirin resistance and its relation to clinical outcome. We excluded papers that did not contain a direct measure of platelet function or any data on clinical outcome in relation to aspirin resistance. Overall we independently reviewed 57 papers in detail. Twenty papers met the inclusion criteria.w2 w3 w10-w13 w14-w20 Figure 1⇓ shows the flow of papers through the trial