Is it possible to define resistance to acetylsalicylic acid and P2Y12 blockers at the patient's bedside?

Multiple assays exist to measure antiplatelet effects of acetylsalicylic acid and clopidogrel, and numerous studies have demonstrated an association between incomplete inhibition with these drugs and risk of cardiovascular events. Simple point-of-care assays are potentially suitable for bedside use, and cutoffs for antiplatelet drug "resistance" diagnosis have been proposed. However, many assays remain poorly standardized and validated, different assays correlate poorly with one another, and there is uncertainty whether resistance is a continuous or a categorical variable. In addition, randomized trials are needed to show that altering therapy based on assay results is beneficial. Routine bedside testing for antiplatelet drug resistance is therefore not recommended until these issues have been resolved. © 2011 LLS SAS. All rights reserved.