Controversy: does prevention of vasospasm in subarachnoid hemorrhage improve clinical outcome?

T he first images of cerebral vasospasm were published in 1951. 1 Although that report was followed by a debate regarding the role of angiographic narrowing in causing neu-rological deficits, 2 the question seemed to be settled by Fisher 3 in 1977 when he reported a strong relationship between angio-graphic vasospasm and delayed neurological deficits. Simple explanations that are consistent with current thinking are usually quickly adopted and rapidly evolve into dogma. Dissenting voices are largely ignored except by a passionate few until the volume of evidence reaches critical mass. It seems that the results of the clazosentan trials 4,5 have brought us to that point in our search for an intervention to prevent delayed cerebral ischemia after subarachnoid hemorrhage. Over the decades, observations have suggested that there was not a one-to-one relationship between vasospasm and delayed ischemia. The acute injury from the hemorrhage itself and the subsequent intracranial circulatory arrest have been long recognized. 6 It is widely accepted that ischemia can occur in the absence of vasospasm.