The Relationship Between Delayed Infarcts and Angiographic Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: Delayed cerebral ischemia is common after aneurysmal subarachnoid hemorrhage (aSAH) and is a major contributor to poor outcome. Yet, although generally attributed to arterial vasospasm, neurological deterioration may also occur in the absence of vasospasm. OBJECTIVE: To determine the relationship between delayed infarction and angiographic vasospasm and compare the characteristics of infarcts related to vasospasm vs those unrelated. METHODS: A retrospective review of patients with aSAH admitted from July 2007 through June 2011. Patients were included if they were admitted within 48 hours of SAH, had a computed tomography scan both 24 to 48 hours following aneurysm treatment and >= 7 days after SAH, and had a catheter angiogram to evaluate for vasospasm. Delayed infarcts seen on late computed tomography but not post-procedurally were attributed to vasospasm if there was moderate or severe vasospasm in the corresponding vascular territory on angiography. Infarct volume was measured by perimeter tracing. RESULTS: Of 276 aSAH survivors, 134 had all imaging requisite for inclusion. Fifty-four (34%) had moderate or severe vasospasm, of whom 17 (31%) had delayed infarcts, compared with only 3 (4%) of 80 patients without vasospasm (P < .001). There were a total of 29 delayed infarcts in these 20 patients; 21 were in a territory with angiographic vasospasm, but 8 (28%) were not. Infarct volume did not differ between vasospasm-related (18 +/- 25 mL) and vasospasm-unrelated (11 +/- 12 mL) infarcts (P = .54), but infarcts in the absence of vasospasm were more likely watershed (50% vs 10%, P = .03). CONCLUSION: Delayed infarcts following aSAH can occur in territories without angiographic vasospasm and are more likely watershed in distribution.