Aspirin Resistance in Acute Ischemic Non-cardioembolic Stroke: Frequency and Clinical Study

Platelet activation in cerebrovascular diseases is associated with recurrent stroke and death. Aspirin is an effective antiplatelet agent, exhibiting its action by irreversibly inhibiting platelet cyclooxygenase-1 enzyme, thus preventing the production of thromboxane A2 (TXA2). Objectives: The study is designed to find the frequency of aspirin resistance (AR) among acute ischemic non-cardioembolic stroke patients, and to assess the clinical picture of those patients. Mehtods: This study included 80 patients39 males and 41 females (mean age: 63 years 11.8 SD), they were diagnosed clinically and via brain imaging within 24 hours following stroke onset. They were given non coated, same preparation of aspirin 150 mg/day regularly and under observation, Low molecular weight heparin 40 mg per day. The patients were followed up clinically and via GCS, NIHSS and APACHEII scales. Assessment of aspirin resistance was done one week after regular aspirin intake through: bleeding time, coagulation time and assessment of thromboxaneA2 level in serum using ELIZA. The patients were classified into two groups aspirin resistant (AR) and aspirin sensitive (AS) and the data were compared in both. Results: AR patients represented 33.75% of our sample. History of TIAs and stroke was more prevalent among them. In AR patients: the followings were also more frequent: more affection of consciousness, power, sensation, language, coordination, vertigo, vomiting, large size of cerebral infarcts, temporal and parietal infarcts. There were high significant negative correlation between GCS and TXA2level and between the later and changes in bleeding time in the first day and 7 days following stroke onset. On the other hand there were high positive correlation between TXA2 level and NIHSS score and infarct size. Coclusion: AR was frequent among ischemic non-cardioembolic stroke and they were associated with history of TIAs and previous strokes, and presented with more severe clinical presentation and larger size of cerebral infarcts, So early identification of AR prevents its fruitless use.