Predictors of rehemorrhage after treatment of ruptured intracranial aneurysms: the Cerebral Aneurysm Rerupture After Treatment (CARAT) study.
OBJECTIVE
The primary purpose of intracranial aneurysm treatment is to prevent rupture. Risk factors for rupture after aneurysm treatment have not been clearly established, and the need to completely occlude aneurysms is debated.


METHODS
The Cerebral Aneurysm Rerupture After Treatment (CARAT) study is an ambidirectional cohort study of all patients with ruptured intracranial aneurysms treated with coil embolization or surgical clipping at 9 high-volume centers in the United States from 1996 to 1998. All subjects were followed through 2005, and all potential reruptures were adjudicated by a panel of 3 specialists without knowledge of the initial treatment or aneurysm characteristics. Degree of aneurysm occlusion post-treatment was evaluated as a predictor of nonprocedural rerupture in univariate Kaplan-Meier analysis (log-rank test) and in a Cox proportional-hazards model after adjustment for potential confounders and censoring at time of retreatment.


RESULTS
Among 1001 patients during a mean of 4.0 years follow-up, there were 19 postprocedural reruptures; median time to rerupture was 3 days and 58% led to death. The degree of aneurysm occlusion after treatment was strongly associated with risk of rerupture (overall risk: 1.1% for complete occlusion, 2.9% for 91% to 99% occlusion, 5.9% for 70% to 90%, 17.6% for <70%; P<0.0001 in univariate and multivariable analysis). Overall risk of rerupture tended to be greater after coil embolization compared with surgical clipping (3.4% versus 1.3%; P=0.092), but the difference did not persist after adjustment (P=0.83).


CONCLUSIONS
Degree of aneurysm occlusion after the initial treatment is a strong predictor of the risk of subsequent rupture in patients presenting with subarachnoid hemorrhage, which justifies attempts to completely occlude aneurysms.
Johnston
S Claiborne
SC
Department of Neurology, Box 0114, University of California, San Francisco, 505 Parnassus Ave, M-798, San Francisco, CA 94143-0114, USA. clay.johnston@ucsfmedctr.org
Dowd
Christopher F
CF
Higashida
Randall T
RT
Lawton
Michael T
MT
Duckwiler
Gary R
GR
Gress
Daryl R
DR
D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000453:epidemiology* / Q000601:surgery; D015331:Cohort Studies; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D055502:Secondary Prevention; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D013525:Surgical Instruments; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology