Background and purpose: It has been reported that nimodipine reduces the frequency of secondary ischemia and improves outcome after aneurysmal SAH, but definitive evidence concerning all available calcium antagonists is lacking.
Methods: Systematic overview of randomized trials that were completed by January 1996 compared calcium antagonists with control and started treatment within 10 days after onset of subarachnoid hemorrhage (SAH) was performed. All calcium antagonists studied thus far (nimodipine, nicardipine, and AT877) were included.
Results: We analyzed 10 trials totaling 2756 patients. The relative risk (RR) reduction of poor outcome (death or dependency) was 16% (95% CI, 6 to 27%) and that of case fatality was 10% (95% CI, -6 to 25%). To prevent one poor outcome, 19 (12 to 59) patients need to be treated. Calcium antagonists give a 33% (95%, CI 25 to 41) RR reduction in the frequency of ischemic neurologic deficit and a 20% (95% CI, 11 to 28) RR reduction in the frequency of CT-scan documented cerebral infarction. Eight (6 to 11) patients need to be treated to prevent one ischemic neurologic deficit. In the analyses for nimodipine only, treatment was associated with a 24% RR reduction of poor outcome (95% CI, 12 to 38). To prevent one poor outcome, 13 (8 to 30) patients need to be treated with nimodipine. The RR reduction of angiographically detected cerebral vasospasm was statistically significant for AT877 (38%; 95% CI, 17 to 54%) and nicardipine (21%; 95% CI, 6 to 34%) but not for nimodipine (9%; 95% CI, -2 to 19%).
Conclusion: Calcium antagonists reduce the proportion of ischemic neurologic deficits and nimodipine improves overall outcome within 3 months of aneurysmal SAH; evidence for a reduction of poor outcome from all causes by nicardipine and AT877 is inconclusive. The intermediate factors by which nimodipine exerts its beneficial effect remain uncertain.