Samarasekera N, Fonville A, Lerpiniere C, Farrall AJ, Wardlaw JM, White PM, et al. Influence of Intracerebral Hemorrhage Location on Incidence, Characteristics, and Outcome: Population-Based Study. Stroke. 2015
Just as in real estate, location within the brain is of utmost importance to a stroke neurologist! Intracerebral hemorrhage outcomes have unfortunately not changed as much as we would have hoped over the past 20 years, with only 60% of patients surviving a month. Those who survive have comparable risks for ischemic v/s hemorrhagic stroke in the future. Given the grim nature of the entity, there has been a lot of focus trying to identify and quantify prognostic factors so that we can help patients and their families make informed decisions. The ICH score was developed in 2001 to predict 1 month mortality, and included age, Glasgow Coma Scale, ICH location, ICH volume, and intraventricular extension as components. Among the components, age and location (supratentorial or infratentorial) were the strongest predictors. ICH grading scale (ICH-GS) was proposed in in 2007 and improved discrimination slightly by using different cutoffs and points assignment. However, location was still classified as supra versus infratentorial. As four fifths of all ICH are supratentorial, there have been few studies focussing on differences in outcome contingent on whether ICH is lobar versus non-lobar, as opposed to supratentorial versus infratentorial. The influence of supratentorial ICH location on outcome is not well established.
In the current issue of Stroke, Samarasekera et al. study the effect of lobar and non-lobar location on outcome in a prospective population-based cohort in Scotland of 695,335 people aged >=16 years. 128 incident primary ICHs between June 2010 – June 2011 were included. An experienced neuroradiologist classified ICH location into non-lobar (brainstem, cerebellum, basal ganglia, internal or external capsule, thalamus) and lobar. Lobar location, constituting 53% of the ICHs was more often associated with prior dementia, lower GCS score, larger volume, as well as subarachnoid and subdural extension. However, lobar hemorrhages were less likely to be dead at 1 year (adjusted OR 0.21, CI 0.07 – 0.63) as compared to non-lobar hemorrhages, after adjustment for known predictors. Supratentorial hemorrhages were associated with lower odds of death at one year as compared to infratentorial hemorrhages. There were 4 recurrent ICHs, all among the lobar ICH group. When the authors reclassified location in the ICH score as lobar, deep or infratentorial, it did not improve the discrimination of ICH score for outcome at 1 year. This is an important study as it validates several observations such as better outcome in lobar ICHs but higher risk of recurrence. Also, it validates the ICH score in a population based cohort and reasserts its discriminative ability. The higher prevalence of dementia in lobar ICH may stem from cerebral amyloid angiopathy.
As the population-based cohort study continues follow-up, it will be an important source of outcome as well as natural history data in intracerebral hemorrhage. Important radiologic and clinical factors will continue to shed more and more light on the subsets of the heterogenous entity of ICH, which in the long run may lead to novel interventions for them. We remain hopeful that we will be able to do better than having 20% patients die within the first 2 days of an ICH.