Introduction: The role of the renin-angiotensin system (RAS) in the pathogenesis of abdominal aortic aneurysms is established. While RAS has an important presence in the cerebral vasculature, its role in aneurysmal subarachnoid hemorrhage (aSAH) is controversial. The Cerebral Aneurysm Renin Angiotensin System study (CARAS) was a prospective study to assess common genetic polymorphisms of RAS and their relation to aSAH.
Methods: Two institutions in the United States participated in CARAS from September 2012 to January 2015. The study group included patients with aSAH. Controls were recruited from a pool of patients admitted for trauma with unremarkable CTA of head and neck. For the genetic evaluation a venous blood sample was obtained from all patients within 72 hours of admission. The common RAS genetic polymorphisms were detected using high resolution DNA melting analysis (DMA) (rs699, rs4340, rs5186, rs11091046) and pyrosequencing (rs4340). Bivariate analysis was performed using IBM SPSS for Windows version 23.
Results: The total number of patients screened was 248. Samples of 149 subjects with aSAH and 50 controls were available for analysis. In patients 55 year of age of older, Allele C of rs11091046 was more common in the aSAH group compared to controls (Cramer’s V test, P = 0.007), and genotype CC of this gene was also more common than genotype AC than AA in the SAH group (Cramer’s V test, P = 0.023). In bivariate, no statistically significant differences were noted in the frequency of any of the studies alleles and genotypes between the aSAH patients and the controls.
Conclusions: This data may potentially indicate that in the studied aSAH patients 55 year of age of older, gene-controlled, RAS-related vascular functioning is likely involved in aSAH. Further studies are now required to further elucidate such process and its potential implication in treatment of patients with aSAH.
Patient Care: Renin-Angiotensin system polymorphisms may serve as a marker for patients with intracranial aneurysms at risk for aSAH.
Learning Objectives: By the conclusion of this session, participants should be able to discuss the role of the renin-Angiotensin System in aSAH.