AspirinWorks: a new immunologic diagnostic test for monitoring aspirin effect

* Atherothrombosis, the major cause of acute coronary syndromes, remains the world's leading cause of morbidity and mortality. Platelets are central to the process of atherothrombosis and, there fore, antiplatelet therapies have been widely advocated in managing this disorder. * Low-dose aspirin (acetylsalicylic acid) is commonly prescribed as an antiplatelet therapy for secondary prevention of serious ischemic events. However, recent reports suggest that not all patients respond to low-dose aspirin to the same degree. Conservative estimates of aspirin nonresponsiveness (also known as 'aspirin resistance') range from 5 to 25%, depending on the testing plat form and clinical status of the tested patient population. * The prevalence of aspirin resistance suggests a need for a test to monitor aspirin response in the individual patient. Such a test would allow for individualized treatment rather than treatment of the disease on a population basis. * Historical methods to assess the effect of aspirin on platelet function involve ex vivo platelet aggregation techniques that are not conducive to mass screening of individuals. * Aspirin exerts its antiplatelet effect through inhibition of the plate let cyclooxygenase (COX) pathway and subsequent reduction in thromboxane [A.sub.2] (Tx[A.sub.2]) production. Assessment of the adequacy of COX-1 pathway inhibition by aspirin can be performed by measuring levels of 11-dehydrothromboxane [B.sub.2] (11dhTx [B.sub.2]), a stable metabolite of Tx[A.sub.2]. * AspirinWorks® is an FDA cleared competitive immunoassay in microplate format that measures levels of 11dhTx[B.sub.2] in urine specimens. This test may be used by physicians to monitor aspirin effect and assist in optimizing antiplatelet therapy in individual patients.