Introduction: Intracranial aneurysms are a major cause of subarachnoid hemorrhage (SAH) and hemorrhagic stroke. Many patients have greater than one aneurysm on presentation, but the exact genetic or environmental factors that predispose a patient towards the development of multiple aneurysm are unclear. We sought to assess the factors predisposing a patient towards multiple aneurysms among patients presenting with subarachnoid hemorrhage.
Methods: Patients presenting to the Columbia University Medical Center Neurological ICU were prospectively enrolled from 1996-2012. Patients with an aneurysm confirmed by angiography that appeared to be the source of the hemorrhage were assessed for clinical and radiographic characteristics that were associated (p<0.2) with one, two, or three or more aneurysms using univariate comparisons (Chi-squared, Mann-Whitney, and Student t-test). Multiple logistic regressions were performed on associated factors.
Results: Of 1277 patients, 890 had one aneurysm, 267 had two aneurysms, and 120 had three or greater aneurysms. Amongst those presenting with SAH, factors associated with a single aneurysm were male gender (OR 1.78; p=0.0276), lower BMI (OR 0.976; p=0.0062). Patients of black ethnicity were less likely to present with a single aneurysm (OR 0.438; p=0.0012). Smoking alone predisposed patients to two aneurysms (OR 1.018/pack-year; p =0.423). In contrast, anti-platelet use was found to be protective (OR 0.342; p = 0.0399). Black ethnicity (OR 2.803; p=0.0003), history of polycystic kidney disease (OR 5.534; p = 0.038), and higher BMI (OR 1.023; p=0.0187) were found to be predictive of patients present with three or more aneurysms.
Conclusions: Patients presenting with SAH and multiple aneurysms can be readily stratified by unique risk factors. Patients with two aneurysms appear to represent a group who is predisposed by environmental factors, whereas patients with three or more aneurysms appear to be predisposed predominantly by genetic factors. However, gender and BMI appear to play a role in all multiple aneurysms.
Patient Care: This project demonstrates that aneurysmal pathogenesis is complex, but may be categorizable based on number.
It also emphasizes several potential inflammatory mechanisms of aneurysmal development.
Learning Objectives: 1) To understand the differential role that genetics and environment may play in aneursm development.
2) To recognize that genetic predispositions may play a greater role in those with greater than 2 aneurysms
3) To understand that the development of one or two aneurysms may be more secondary to environmental factors.
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