OBJECTIVE:A small number of patients with aneurysmal subarachnoid hemorrhage have angiographic evidence of cerebral vasospasm within 48 hours of the onset of hemorrhage. The present study analyzes the prognostic value and determinants of this ultraearly angiographic finding.METHODS:We analyzed prospectively collected data from the placebo-treated group in a multicenter clinical trial conducted at 54 neurosurgical centers in North America. The presence and severity of ultraearly angiographic vasospasm (UEAV) was determined by a blinded review of the admission angiograms. Using logistic regression analysis, we identified independent determinants of UEAV from demographic, clinical, laboratory, and neuroimaging characteristics of the patients. The impact of UEAV on the risk of symptomatic vasospasm and 3-month outcome was analyzed after adjusting for potential confounding factors.RESULTS:Of 296 patients in the analysis, 37 (13%) had angiographic evidence of vasospasm at admission. An initial Glasgow Coma Scale score of less than 14 (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-6.0), and serum sodium greater than 138 mmol/L (OR, 3.4; 95% CI, 1.5-8.3) were associated with UEAV. UEAV was associated with increased risk of symptomatic vasospasm (OR, 2.5; 95% CI, 1.2-5.4) and poor outcome at 3 months (OR, 2.8; 95% CI, 1.2-6.3), after adjusting for other variables. This risk of symptomatic vasospasm was not influenced by early surgery (within 48 h of hemorrhage onset). Poor outcome was more likely to occur in patients with UEAV who did not undergo early surgery (P= 0.03).CONCLUSION:Our analysis suggests that patients with angiographic evidence of vasospasm at admission are at high risk for both symptomatic vasospasm and poor outcome. We also found that early surgery did not aggravate this risk.