Effects of insular involvement on functional outcome after intracerebral hemorrhage

Objective: Ischemic stroke, as well as intracerebral hemorrhage (ICH), involving the insular cortex tends to be more severe. The impact of insular involvement on outcome of ICH remains enigmatic.

Methods: We analyzed 159 patients with supratentorial ICH. Depending on insular involvement the patients were classified into two groups (ICH_non-insular vs. ICH_insular ). Volume and symptom severity of ICH were assessed. Electrocardiography, chest X-ray, and laboratory examinations including myocardial enzymes and inflammatory markers were made. In-hospital death and outcome at discharge from hospital were assessed on the modified Rankin scale (mRS).

Results: The main finding was an association of insular involvement of ICH with worse short-term outcome as measured by mRS (common odds ratio: 4.08 (95% CI: 2.09-7.92); p < .001). This association survived adjustment to relevant covariates such as age, sex, ICH volume, intraventricular hemorrhage, pneumonia, and length of stay (adjusted common odds ratio: 2.51 (95% CI: 1.21-5.21); p = .014) but had no predictive value for side of ICH or rate of atrial fibrillation. There was no association of ICH localization with in-hospital death rate.

Conclusion: Insular localization of ICH lesions predicts worse short-term functional outcome independent of side of bleeding or cardiac dysfunction such as new AF. These findings need clarification in larger prospective cohorts assessed by detailed autonomic/cardiac testing, as well as neuroimaging sub-localization of ICH within the insular region.