Vasospasm is a condition whereby arterial diameter narrows with a resultant decrease in blood flow and in turn oxygen delivery (Figure 1,2). Muscular contraction of the arterial wall may be caused by surgical manipulation or medications but occurs most notably after aneurysmal subarachnoid hemorrhage. Classically, vasospasm develops in up to 20% of patients within 4-14 days after aneurysmal subarachnoid hemorrhage. The delayed complications related to ischemic stroke such as paralysis, loss of the ability to speak or coma may occur after what had been an otherwise uneventful aneurysmal clipping or coiling.

Figure 1
Left: AP angiogram showing vasospasm of the internal carotid, middle cerebral and anterior cerebral arteries (arrows). Right: AP angiogram after treatment with balloon angioplasty showing an increase in the diameter of vessels (arrows).