Resistance to acetylsalicylic acid - pathophysiology and clinical implications

Abstract

Cardiovascular diseases are the most common cause of morbidity and mortality. Acetylsalicylic acid (ASA) is an effective antiplatelet drug which decreases the risk of myocardial infarction, stroke and sudden death by 25% in groups with higher cardiovascular risk. The high efficacy of ASA in primary and secondary prevention of cardiovascular events might be diminished in cases of ASA resistance, as reported in 5-45% of patients. Acetylsalicylic acid resistance is diagnosed by clinical symptoms (thrombotic event during ASA therapy) or markers of platelet aggregation. Small observational have studies revealed higher cardiovascular risk in populations with ASA resistance. Beyond incomplete inhibition of COX-1, mechanisms of ASA resistance are still not well known. Duration of therapy, lack of compliance and drug interactions are considered as possible factors in the development of ASA resistance. Our review describes all known mechanisms of ASA resistance and their clinical consequences. We have also pointed out the need for the development of universally accepted diagnostic criteria and screening guidelines for ASA resistance.