Cerebral vasospasm: looking beyond vasoconstriction

Cerebral vasospasm is an important syndrome that afflicts 30% of patients in the aftermath of, and secondary to, subarachnoid hemorrhage. Starting approximately one week after the hemorrhage, the condition worsens the prognosis of the hemorrhage significantly. Apart from general supportive care, no treatment exists for cerebral vasospasm. During the past 50 years, it was thought that the ischernia that signifies poor outcome is more or less exclusively caused by arterial narrowing. However, this idea has recently been challenged by the failure of the drug clazosentan to improve patient outcome, despite reversing vasoconstriction. In this article, we discuss the opinion that factors other than vasoconstriction are important in the pathophysiology and prognosis of cerebral vasospasm. Such factors include global ischernia, disruption of the blood-brain barrier, activation of apoptotic and inflammatory pathways, and cortical spreading depression.