Distribution of delayed ischemic neurological deficits after aneurysmal subarachnoid hemorrhage and implications for regional neuromonitoring

ObjectivesMany neuromonitoring devices provide data applicable to a limited region of the brain. Risk of DIND is common after aSAH and may occur near or remote from the ruptured aneurysm. The aim of this study is to determine the distribution of DIND after aneurysms rupture as it relates to the potential value of regional monitoring in detection of vasospasm.Patients and methodsThe study enrolled aSAH patients presenting to a tertiary referral center over a three year period who received treatment for an identified ruptured aneurysm and survived >10 days with subsequent DIND. Only those patients receiving routine neuroimaging were included. To account for the anticipated effect on infarct distribution, patients were divided into groups of midline and non-midline aneurysms and assessed for vasospasm and stroke with respect to vascular distribution. Comparisons of clinical characteristics were made to determine factors predisposing to remote infarction.ResultsTwenty-nine patients met criteria with 15 patients harboring non-midline aneurysms. The rarity of isolated remote DIND prohibited adequate assessment of predictive clinical characteristics. For non-midline aneurysms, DIND occurred ipsilateral to the ruptured aneurysm in 93% and within the same vascular territory in 86% of patients. Midline anterior circulation aneurysms frequently resulted in ACA infarction. A neuromonitoring device with 100% sensitivity for ischemia placed in the MCA territory ipsilateral to a non-midline ruptured aneurysm would identify 71% of DIND.ConclusionVasospasm related infarction occurs most commonly ipsilateral to or in the same distribution of the ruptured aneurysm. Less anatomical correlation is seen with midline aneurysms. Rupture of posterior circulation aneurysms infrequently results in supratentorial infarction. Decisions regarding placement of regional monitors for the purpose of vasospasm detection should consider this distribution of ischemic risk.