Impact of hospital-related factors on outcome after treatment of cerebral aneurysms.

BACKGROUND AND PURPOSE The goal of this study was to examine the impact of hospital characteristics on outcome after the treatment of ruptured and unruptured cerebral aneurysms. METHODS We identified all discharges in New York State from 1995 through 2000 with a principal diagnosis of subarachnoid hemorrhage (SAH) or unruptured cerebral aneurysm (UCA) in patients who were treated by aneurysm clipping, wrapping, or endovascular coiling. An adverse outcome was defined as in-hospital death or discharge to a rehabilitation hospital or long-term facility. We examined the effect of hospital factors, including the rate of endovascular therapy and overall procedural volume, on outcome, length of stay, and total charges. RESULTS There were 2200 (36.9%) and 3763 (63.1%) admissions for attempted treatment of UCA and SAH, respectively. The 10 highest-volume hospitals performed half of all the procedures. Overall, hospital volume was associated with fewer adverse outcomes and lower in-hospital mortality for both UCA (adverse outcome: odds ratio [OR], 0.89; P<0.0001; mortality: OR, 0.94; P=0.002 for each 10 additional procedures performed per year) and SAH (adverse outcome: OR, 0.94; P=0.03; mortality: OR, 0.95; P=0.005). Use of endovascular therapy (each additional 10% of cases performed endovascularly) was associated with fewer adverse outcomes after treatment of unruptured aneurysm (0.83, P=0.026). Hospital volume had more of an effect on outcome after aneurysm clipping than after endovascular therapy. CONCLUSIONS Hospital procedural volume and the propensity of a hospital to use endovascular therapy are both independently associated with better outcome. Improvement in outcome could be achieved by a program of regionalization and selective referral for the treatment of cerebral aneurysms.