Predictors of rerupture after intracranial aneurysm treatment have not yet been evaluated in detail.OBJECTIVE
To identify predictors of rerupture after treatment of intracranial aneurysmDESIGN AND INTERVENTION
The investigators analyzed data on 1,001 patients from the Cerebral Aneurysm Rerupture After Treatment (CARAT) study, which was designed to compare rerupture rates after a subarachnoid hemorrhage (SAH) that was treated initially with coil embolization or surgical clipping. The study was conducted at nine US hospitals and included adults who were discharged in the period 1996-1998 with a primary diagnosis of SAH. Information about the patient, index aneurysm (defined as any aneurysm that was considered to be a possible source of the initial SAH and that was treated during the initial procedure) and procedure undertaken was obtained from medical records. Postprocedural angiograms or operative reports were used to estimate the degree of aneurysm occlusion. Records were examined by a neurologist, a neurosurgeon and a neurointerventionalist, and agreement of at least two reviewers was required to classify an event as rerupture. The following variables were evaluated as potential predictors of postprocedural rerupture after aneurysm treatment: demographic factors, treatment type, medical history, aneurysm size and location, and percentage occlusion of the aneurysm after treatment.OUTCOME MEASURE
The primary study end point was rerupture of the index aneurysm.RESULTS
During a mean follow-up of 3.6 years (range 0-9.6 years), there were 19 postprocedural reruptures. The median time to rerupture was 3 days (range 1 day to 1.1 years), and the majority (58%) of patients with a rerupture died within 1 month of the event. Rerupture was strongly associated with the degree of aneurysm occlusion-the cumulative risks were 1.1%for complete occlusion, 2.9% for 91-99% occlusion, 5.9% for 70-90% occlusion, and 17.6% for <70% occlusion (P<0.0001 by log-rank test).The association remained significant (P<0.001) after adjustment for other potential predictors of rerupture. In univariate analysis, the risk of rerupture tended to be greater after coil embolization than after surgical clipping (cumulative risk 3.4% vs 1.3%; P=0.09). However, the rate of complete aneurysm occlusion achieved differed significantly between the two groups (92% after clipping and 39% after coiling; P<0.0001), and after adjustment for this and other potential confounders the risk of rerupture in patients treated with coil embolization was similar to that in patients who had undergone clipping (hazard ratio 1.09 [95% CI 0.32-3.69]; P =0.89). The only other factor that independently predicted rerupture was a history of peripheral vascular disease. The data indicated no increased risk of intraoperative or perioperative complications when more- complete aneurysm occlusion was attempted, although greater degrees of occlusion achieved during coiling tended to be associated with a greater risk of new disability (P=0.07).CONCLUSION
Incomplete occlusion of a ruptured intracranial aneurysm is a strong predictor of rerupture.