gms | German Medical Science

Objective: Aneurysmal re-rupture prior to treatment is a major cause of death and morbidity in aneurysmal subarachnoid hemorrhage. Recognizing risk factors for aneurysmal rebleeding is particularly relevant, and might identify the aneurysms that benefit from acute treatment. It is uncertain whether the size of the aneurysm is related to rebleeding. This meta-analysis was performed to evaluate whether an association could be determined between aneurysmal diameter and rebleeding rate before treatment. Potentially confounding factors like age, aneurysm location and the presence of hypertension are also evaluated.

Method: The authors systematically searched the Pubmed, Embase and Cochrane databases up to April 3, 2013 for studies of patients with aneurysmal subarachnoid hemorrhage that reported the association between aneurysmal diameter and pre-treatment aneurysmal rebleeding. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria were used to evaluate study quality.

Results: Seven studies, representing 2121 patients were included in the quantative analysis. Almost all of the studies used 10mm as the cut-off point for size among others classes, with only one using 7mm. An analysis was performed with this best unifiable cutoff point. Overall rebleeding occurred in 360 of 2121 patients (mean 17.0%, range 8.7%-28.4%). The rate of rebleeding in small and large aneurysms was 14.0% and 23.6%, respectively. The meta-analysis of the seven studies revealed that larger sized aneurysms had a higher risk for rebleeding (OR 2.56 [95% CI 1.62- 4.06]; p=0.00; I2=60%). The sensitivity analysis did not alter the results. Five of the seven studies reported data regarding age; four studies provided age adjusted results and identified a persistent relationship between size and the risk of rebleeding. The presence of hypertension was reported in two studies and was more prevalent in patients who rebled in one of these. Location (anterior versus posterior circulation) was reported in five studies, while in four there was no difference in the rebleed rate. One study identified a lower risk of rebleeding for posterior location aneurysms.

Conclusions: This meta-analysis showed that aneurysm size is an important risk factor for aneurysmal rebleeding and should be used in the clinical risk assessment of individual patients. Our results confirmed the current guidelines and stressed the importance of acute treatment for large ruptured aneurysms.