Does aneurysm side influence the infarction side and patients´ outcome after subarachnoid hemorrhage?

Background: The prognostic factors and outcome of aneurysms appear to be dependent on its locations. Therefore, we compared left- and right- sided aneurysms in patients with aneurysmal subarachnoid hemorrhage (SAH) in terms of differences in outcome and prognostic factors. Methods: Patients with SAH were entered into a prospectively collected database. A total of 509 patients with aneurysmal subarachnoid hemorrhage were retrospectively selected and stratified in two groups depending on side of ruptured aneurysm (right n = 284 vs. left n = 225). Midline aneurysms of the basilar and anterior communicating arteries were excluded from the analysis. Outcomes were assessed using the modified Rankin Scale (mRS; favorable (mRS 0–2) vs. unfavorable (mRS 3–6)) six months after SAH. Results: We did not identify any differences in outcome depending on left- and right-sided ruptured aneurysms. In both groups, the significant negative predictive factors included clinical admission status (WFNS IV+V), Fisher 3- bleeding pattern in CT, the occurrence of delayed cerebral ischemia (DCI), early hydrocephalus and later shunt-dependence. The side of the ruptured aneurysm does not seem to influence patients´ outcome. Interestingly, the aneurysm side predicts the side of infarction, with a significant influence on patients´ outcome in case of left-sided infarctions. In addition, the in multivariate analysis side of aneurysm was an independent predictor for the side of cerebral infarctions. Conclusion: The side of the ruptured aneurysms (right or left) did not influence patients’ outcome. However, the aneurysm-side predicts the side of delayed infarctions and outcome appear to be worse in patients with left-sided infarctions.