H-Type Hypertension and Aneurysm Instability: An Observational and Genetic Study

Background: Unruptured intracranial aneurysms (UIAs) pose a significant risk of subarachnoid hemorrhage. Both hypertension and hyperhomocysteinemia are recognized as independent risk factors for vascular disease; however, their combined impact (H-type hypertension) on aneurysm instability and rupture remains unclear. Methods: We analyzed a prospective cohort of 358 adults with UIAs (475 aneurysms) using high-resolution vessel-wall MRI (HRVWI) for cross-sectional and longitudinal assessment. H-type hypertension was defined as hypertension with plasma homocysteine ?10 ?mol/L. Multivariable logistic regression assessed associations with AWE and aneurysm growth (longitudinal sub-cohort: n = 82, 89 aneurysms). Mendelian randomization (MR) analyses evaluated the causal role of homocysteine in hypertension and aSAH. Proteomic profiling identified potential molecular mechanisms. Results: AWE occurred in 33.7% of aneurysms, which were larger, irregular, and had higher PHASES scores. Elevated homocysteine (10.3 vs 9.5 ?mol/L, p = 0.004) and H-type hypertension (43.8% vs 28.3%, p < 0.001) were associated with AWE. After adjustment, H-type hypertension independently predicted AWE (OR = 3.18) and aneurysm growth (OR = 3.63). MR analyses showed homocysteine increased aSAH (OR = 1.39) and hypertension risk (OR = 1.10), while hypertension increased aSAH risk (OR = 1.58). Mediation analysis did not support hypertension as a mediator (p = 0.20). Proteomic analyses identified key pathways related to inflammation?immune dysregulation, extracellular matrix remodeling, and signaling activation as potential mediators. Conclusions: H-type hypertension amplifies aneurysmal-wall instability and growth. Combined control of blood pressure and homocysteine merits prospective evaluation for UIA prevention.