Treatment of Unruptured Intracranial Aneurysms: a Nationwide Assessment of Effectiveness

Background And Purpose: With advances in neuroimaging, unruptured cerebral aneurysms are being diagnosed more frequently. Until 1995, surgical clipping of the aneurysm was the only treatment available. Since then, a less invasive endovascular technique has been found effective in a trial of ruptured aneurysms. No efficacy studies comparing the 2 procedures for unruptured aneurysms exist to guide clinical decisions. The objective of this study was to assess effectiveness and outcomes of endovascular versus neurosurgical treatment for unruptured intracranial aneurysms.

Methods: This was a retrospective cohort study, using data collected over a 1-year time interval (between 1998 and 2000), from 429 hospitals, in 18 states, and representing 58% of the US population. A total of 2535 treated, unruptured cerebral aneurysm cases were evaluated. The measurements used were effectiveness as measured by hospital discharge outcomes: 1) mortality (in-hospital death), 2) adverse outcomes (death or discharge to a rehabilitation or nursing facility), 3) length of stay, and 4) hospital charges. Univariate analyses compared endovascular versus neurosurgical discharge outcomes. Multivariable models were adjusted for age, sex, region, Medicaid insurance status, year, hospital case volume, comorbidity score, and admission source.

Results: Endovascular treatment was associated with fewer adverse outcomes (6.6% versus 13.2%), decreased mortality (0.9% versus 2.5%), shorter lengths of stay (4.5 versus 7.4 days), and lower hospital charges (42,044 dollars versus 47,567 dollars) compared with neurosurgical treatment (P < .05). After multivariable adjustment, neurosurgical cases had 70% greater odds of an adverse outcome, 30% increased hospital charges, and 80% longer length of stay compared with endovascular cases (P < .05).

Conclusions: The current analysis indicates that endovascular therapy is associated with significantly less morbidity, less mortality, and decreased hospital resource use at discharge, compared with conventional neurosurgical treatment for all unruptured aneurysms. Endovascular therapy, as a treatment alternative to surgical clipping, should be offered as a viable therapeutic option for all patients considering treatment of an unruptured cerebral aneurysm.