Deep, spontaneous intracerebral hemorrhages: Clinical differences and risk factors associated with anterior versus posterior circulation

Background: spontaneous intracerebral hemorrhages (ICH) in different anatomical locations are considered different clinical entities, associated with different vascular etiologies. However, such a distinction between deep ICH in the posterior vs. the anterior circulation is not well documented.

Objective: to look for different demographic, clinical, laboratory and radiological variables in order to clarify any distinction between deep ICH of the posterior versus the anterior circulations.

Material and methods: Retrospective study on patients diagnosed with deep, spontaneous ICH at a single tertiary center. Patients were divided into two groups: posterior circulation (group 1) and anterior circulation (group 2). Computerized medical records were extracted for multiple variables.

Results: A total of 142 patients with deep ICH were included in the study; 54.9 % (n = 78) with posterior (group 1) and 45.1 % (n = 64) with anterior circulation hemorrhages (group 2). In group 1, 67.9 % (n = 53) of hemorrhages were in the cerebellum and 28.2 % (n = 22) in the thalamus. Patients in group 1 were older at time of hemorrhage (68.69 ± 11.66 vs. 64.95 ± 13.34, p = 0.073) and had nearly threefold increased rate of BMI≥ 35 (22.0 % vs. 8.6 %, p = 0.071). In multivariate analysis, use of anti-aggregates (OR=2.391; 95 % CI 1.082-5.285, p = 0.031) and past medical history of HTN (OR=2.904; 95 % CI 1.102-7.654, p = 0.031) were significantly associated with ICH of the posterior circulation. When excluding patients with thalamic hemorrhages, BMI ≥ 35 was also associated with significant risk of having a deep hemorrhage in the posterior circulation vs. the anterior circulation (OR=3.420; 95 % CI 1.011-11.574, p = 0.048). No significant differences were found between the two groups in terms of functional and survival outcomes.

Conclusion: HTN, use of anti-aggregates and morbid obesity are associated with deep ICHs of the posterior circulation and should be considered significant risk factors for this major clinical event. The growing data on pathophysiology of distinct subgroups of ICH will provide useful tools that will aid in preventing and treating these neurological emergencies. Future epidemiological and clinical studies should use the distinction between ICH subgroups based on their anatomical location and vascular territories as accurately as possible in order to reach solid conclusions.