2-YEAR FOLLOW-UP OF ASPIRIN RESPONDER AND ASPIRIN NONRESPONDER - A PILOT-STUDY INCLUDING 180 POSTSTROKE PATIENTS

Aspirin is proposed to be effective in stroke-prophylaxis because it c ompletely inhibits the platelet prostanoid-pathway. In about 90% of st roke victims, increased platelet reactivity (PR) can be reduced to the normal range by aspirin. Twelve hours later, about one third of them show an enhanced PR again. These patients are called secondary aspirin non responders (SANR). In this study the potential pathogenetic and p rognostic impact of this biological feature on stroke recurrence was e valuated. Before discharge from the hospital, PR was determined 12 hou rs after an oral administration of 500 mg aspirin in 180 patients aged 58 +/- 15 years; 74 were female and 106 male. All had suffered a stro ke in the internal carotid artery territory. Patients were treated wit h 3 x 500 mg aspirin/d and were followed up over a 24-month period. Ma jor endpoints of this study were stroke, myocardial infarction or vasc ular death. On discharge from the hospital, 120 of the 180 patients sh owed a normal PR under aspirin treatment. High test values were found in 60 patients (SANR). Six patients were lost for follow-up. Because o f side effects 36 (20%) of the 180 patients enrolled discontinued medi cation. Major endpoints occurred in 4 of these 36 patients (11%) and i n 25 of the 138 remaining patients (18.1%); 19 patients died in conseq uence of a vascular event during the observation period. Major endpoin ts were seen in only 5 of 114 (4.4%) of the aspirin responders, but in 24 out of 60 SANR (40%, p < 0.0001). It may be assumed that early ide ntification of SANR's is a clinically useful tool to classify patients at high risk for recurrence of vascular events. This may be an import ant step to a more effective prevention in post-stroke patients.