Aspirin resistance: what the cardiologist needs to know?

"Aspirin resistance" can be defined as the inability of aspirin to inhibit cyclooxygenase (COX)-1 dependent thromboxane (TX) A2 production, and consequently TX A2-dependent platelet functions. Several laboratory methods have been proposed, to evaluate platelets' resistance to antiplatelet treatment (bleeding time, light transmission aggregation, impedance aggregation, platelet function analyser, rapid platelet function assay, TXB2, flow cytometry). However, all these methods have their advantages intrinsic limitations. Although aspirin resistance appears to be linked to worse long-term outcomes in cardiovascular disease patients, clinical treatment of aspirin resistance, including an increased aspirin dose or the addition of other antiplatelet drugs, is not often effective. Further studies needed to elucidate the appropriate management of aspirin resistance.