From aspirin to aspirin resistance - History, biochemical background, diagnostics and clinical relevance

The story of success of aspirin has lasted for more than 100 years. Initially used as an analgetic with anti-inflammatory, antirheumatic as well as antipyretic effects, aspirin has been widely used as antithrombotic drug since the 1970s, too, due to its more recently discovered platelet inhibitory efficacy. Primary and secondary prophylaxis of cardiovascular events by long-term intake of aspirin has been performed million-fold worldwide, even without any medical attendance. In spite of a clear positive effect on the incidence of coagulation disorders, a residual risk remains for the aspirin user-the aspirin resistance. In this review a short historical survey is given, and the biochemical background of the aspirin effect on blood platelets as well as aspirin resistance with the possible causes and the clinical relevance are described. Different laboratory methods for detection of aspirin resistance are discussed with respect to validity and limitations. Not until both the predisposition for aspirin resistance and the presence of acute aspirin resistance can be clearly detected using reliable methods, the patient will receive adequate treatment.