Magnesium sulfate for aneurysmal subarachnoid hemorrhage: the end of the road or more trials?

Delayed cerebral ischemia (DCI) is a feared complication and an important cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). In the current study, Wong and colleagues performed a systematic review and meta-analysis of randomized controlled trials that investigated the efficacy of magnesium sulfate in patients with aneurysmal SAH. Outcome measures were DCI, cerebral infarction, and functional outcome 3 and 6 months after SAH. Magnesium sulfate decreased the rate of cerebral infarction, but not of DCI or poor functional outcome. Regarding outcome, a beneficial effect of magnesium sulfate on outcome can not be ruled out because of sample size limitations. Even if this meta-analysis had shown an effect on outcome, the question remains which treatment protocol should be applied in daily practice, since the administration of magnesium sulfate differed between most included studies. The present meta-analysis also underlines the importance of defining clinically relevant endpoints in SAH trials. Clinical deterioration due to DCI is more subject to inter-observer bias compared to cerebral infarction, which represents the ultimate outcome of the ischemic event. The Magnesium in Aneurysmal Subarachnoid Hemorrhage-II (MASH-II: ISRCTN68742385) phase III clinical trial nears completion. It aims to include 1,200 patients, and its results are urgently awaited.