Hematoma location and morphology of anticoagulation-associated intracerebral hemorrhage

Objective To study hematoma location and morphology of intracerebral hemorrhage (ICH) associated with oral anticoagulants (OAC) and delineate causes and mechanism. Methods We performed a systematic literature research and meta-analysis of studies comparing neuroimaging findings in patients with OAC-ICH compared to those with ICH not associated with OAC (non-OAC ICH). We calculated pooled risk ratios (RRs) for ICH location using the Mantel-Haenszel random-effects method and corresponding 95% confidence intervals (95% CI). Results We identified 8 studies including 6,259 patients (OAC-ICH n = 1,107, pooled OAC-ICH population 17.7%). There was some evidence for deep ICH location (defined as ICH in the thalamus, basal ganglia, internal capsule, or brainstem) being less frequent in patients with OAC-ICH (OAC-ICH: 450 of 1,102/40.8% vs non-OAC ICH: 2,656 of 4,819/55.1%; RR 0.94, 95% CI 0.88–1.00, p = 0.05, I 2 = 0%) while cerebellar ICH location was significantly more common in OAC-ICH (OAC-ICH: 111 of 1,069/10.4% vs non-OAC ICH: 326 of 4,787/6.8%; RR 1.45, 95% CI 1.12–1.89, p = 0.005, I 2 = 21%) compared to non-OAC ICH. There was no statistically significant relationship to OAC use for lobar (OAC-ICH: 423 of 1,107/38.2% vs non-OAC ICH: 1,884 of 5,152/36.6%; RR 1.02, 95% CI 0.89–1.17, p = 0.75, I 2 = 53%, p for heterogeneity = 0.04) or brainstem ICH (OAC-ICH: 36 of 546/6.6% vs non-OAC ICH: 172 of 2,626/6.5%; RR 1.04, 95% CI 0.58–1.87, p = 0.89, I 2 = 59%, p for heterogeneity = 0.04). The risk for intraventricular extension (OAC-ICH: 436 of 840/51.9% vs non-OAC ICH: 1,429 of 3,508/40.7%; RR 1.26, 95% CI 1.16–1.36, p I 2 = 0%) was significantly increased in patients with OAC-ICH. We found few data on ICH morphology in OAC-ICH vs non-OAC ICH. Conclusion The overrepresentation of cerebellar ICH location and intraventricular extension in OAC-ICH might have mechanistic relevance for the underlying arteriopathy, pathophysiology, or bleeding pattern of OAC-ICH, and should be investigated further.