Factors Predicting the Need for Shunting in Patients with Aneurysmal Subarachnoid Hemorrhage - Univariate Analysis and Logistic Regression Analysis -

ABSTRACT

OBJECTIVE: Chronic hydrocephalus is one of the major complications following aneurysmal subarachnoid hemorrhage(SAH). However the incidence and predicting factors requiring shunting after SAH is not precisely known. The authors investigated the incidence of chronic hydrocephalus, timing of shunting procedure, and factors to predict the need for shunting in patients with aneurysmal SAH. PATIENTS AND METHODS: A series of 209 patients admitted to our institute from January 1993 to December 1997, who presented with SAH and underwent craniotomy for aneurysm clipping were studied retrospectively. Chronic hydrocephalus was defined as clinically and radiographically demonstrated hydrocephalus that lasted 2 weeks or longer after initial hemorrhage and that required shunting. The author divided study group into shunt group(SG, n=20) and non-shunt group(NSG, n=189). Patients were evaluated based on following factors age, sex, history of hypertension and diabetes mellitus, consciousness at admission, Hunt-Hess grade, the presence of intracranial hemorrhage, Graeb's score, bifrontal index(BFI), Fisher grade, amount of SAH, location of aneurysm, time of aneurysm clipping, rebleeding, and vasospasm. RESULTS: The incidence of chronic hydrocephalus was 9.6%(20/209). The timing of the shunting procedure ranged from 16 days to 150 days after initial hemorrhage with the average being 77(+/-37)days. In a univariate analysis with chi-square test, age, consciousness, Hunt-Hess grade, amount of SAH, BFI, Fisher grade, and Graeb's score were significantly related with the need for shunting(p<0.05). In a multivariate logistic regression analysis, odds ratio was calculated for each variables. If the odds ratio of below 60 year of age was 1.0 then that of above 61 was 5.4(p<0.001). If the odds ratio of alert/drowsy was 1.0 then that of stupor/coma was 4.4(p<0.05). If the odds ratio of 0 of Graeb's score was 1.0 then that of 1-10 was 4.3(p<0.05). If the odds ratio of amount of SAH below score 3 was 1.0 then that of above score 4 was 1.8. If the odds ratio of BFI below 30 was 1.0 then that of above 31 was 1.1. CONCLUSION: The development of chronic hydrocephalus after aneurysmal SAH is multifactorial, but should be strongly suspected in patients with older age, decreased level of consciousness or IVH at admission. The patients require a shunt from 2 weeks to 5 months from the time of their initial hemorrhage.