Risk of unruptured aneurysm treatment in California
Background. Few studies have directly compared the risk of cerebral aneurysm repair with surgery and with endovascular coil embolization. Since the vast majority of patients with unruptured cerebral aneurysms are non-disabled prior to treatment, this diagnosis provides an opportunity to compare risks of treatment. Methods. Discharge abstracts for all patients with a primary diagnosis of unruptured cerebral aneurysm were retrieved from a statewide database of non-Federal hospital discharges in California from January 1990 through December 1998. Admissions for initial treatment and all follow-up care were combined to reflect the entire course of therapy. An adverse event was defined as an in-hospital death or discharge to nursing home or rehabilitation hospital at any point during the treatment course. Results. A total of 2069 patients were treated for unruptured aneurysms. Adverse outcomes were more frequent in the 1699 patients treated with surgery than in the 370 treated with endovascular therapy (25% vs. 10%; p<0.0001 by chi-square test). The difference persisted after adjustment for age, gender, race, source of admission, and year of treatment (odds ratio 3.5 for adverse events surgery vs. endovascular therapy, 95% confidence interval 2.4–5.2, p<0.0001 by logistic regression). In-hospital deaths occurred in 3.5% of surgical cases and 0.5% of endovascular cases (p=0.003), and the difference remained significant after adjustment in multivariable models (odds ratio 6.3, 1.5–26.2, p=0.01). Adverse events were less likely at hospitals treating a larger portion of patients with endovascular therapy after adjustment for case characteristics, hospital treatment volume, and clustering of observations using generalized estimating equations (p=0.006). Conclusions. In California, endovascular repair of unruptured cerebral aneurysms is associated with fewer adverse events and in-hospital deaths than surgery.