ASPIRIN AND DELAYED CEREBRAL-ISCHEMIA AFTER ANEURYSMAL SUBARACHNOID HEMORRHAGE

This follow-up study was designed to evaluate whether the use of aspir in either before or after aneurysm rupture affects the occurrence of d elayed cerebral ischemia. Aspirin inhibits platelet function and throm boxane production and has been shown to reduce the risk of various car diovascular and cerebrovascular ischemic diseases. Following admission , the patients in this study were interviewed regarding their use of a spirin and other medicines prior to and after hemorrhage, and their ur ine was screened qualitatively for salicylates. Patient outcome and th e occurrence of hypodense lesions consistent with cerebral infarction on follow-up computerized tomography (CT) were studied prospectively u p to 1 year after hemorrhage. Of 291 patients, 31 (11%) died because o f the initial hemorrhage and 18 (6%) died due to rebleeding within 4 d ays after hemorrhage. Of the remaining 242 patients, 90 (37%) had dela yed cerebral ischemia, which caused a permanent neurological deficit o r death in 54 patients (22%). Of 195 patients undergoing follow-up CT, 85 (44%) had cerebral infarction that was not seen on the CT scan obt ained on admission. Those who had salicylates in the urine on admissio n had a relative risk of 0.40 (95% confidence interval (CI), 0.15 to 1 .10) of delayed ischemia with fixed deficit and a risk of 0.40 (95% CI , 0.18 to 0.93) of cerebral infarction compared with patients who did not have salicylates in their urine. This reduced risk of ischemic com plications with aspirin use was restricted to those patients who used aspirin before hemorrhage, when the risk of ischemia was 0.21 (95% CI, 0.03 to 1.63) and the risk of infarct was 0.18 (95% CI, 0.04 to 0.84) compared with those who had not used aspirin. The reduced risk of cer ebral infarction remained significant after adjustment for several pot ential confounding factors (adjusted risk 0.19; 95% CI, 0.04 to 0.89). These observations suggest that platelet function at the time of suba rachnoid hemorrhage may be associated with delayed cerebral ischemia a fter aneurysm rupture.