Cerebral vasospasm after subarachnoid hemorrhage: the emerging revolution

Cerebral vasospasm is the classic cause of delayed neurological deterioration after aneurysmal subarachnoid hemorrhage, leading and thus to poor outcome and to cerebral ischemia and infarction occasionally death. Advances in diagnosis and treatment-principally the use of nimodipine, intensive care management, hemodynamic manipulations and endovascular neuroradiology procedures-have a improved the prospects for these patients, but outcomes remain disappointing. Recent clinical trials have demonstrated marked prevention of vasospasm with the endothelin receptor antagonist clazosentan, yet patient outcome was not improved. This Review considers possible explanations for this result and proposes alternative causes of neurological deterioration and poor outcome after subarachnoid hemorrhage, including delayed effects of global cerebral ischemia, thromboembolism, microcirculatory dysfunction and cortical spreading depression.