Abstract 55: Intensive Blood Pressure Treatment Remodels Brain Perivascular Spaces: A Secondary Analysis Of The SPRINT MIND Trial

Introduction: Perivascular spaces (PVS) contribute to brain waste clearance pathways, possibly via arterial pulsatility, and are implicated in neurodegenerative disease. Aging, hypertension, and small vessel disease are associated with enlarged PVS, but the effect of intensive blood pressure (BP) control on PVS structure is unknown. Methods: This is a secondary analysis of the SPRINT-MIND MRI substudy, in which participants with cardiovascular risk but without clinical stroke were randomized to intensive BP control (systolic <120) or standard control (<140) and underwent MRI brain at baseline and 4 years. An established spatial filtering algorithm was applied to T2 images to automatically segment PVS within the supratentorial white matter and basal ganglia. PVS volumes were calculated as a percentage of the tissue volume analyzed. We tested for an effect of intensive BP treatment over time on PVS volume fraction using mixed-effects linear models, including random effects for subject and site, and fixed effects for treatment, timepoint, treatment-by-time interaction, age, and sex. Results: At randomization 658 participants had useable images (mean age = 67 years, 60% female), and PVS volume fraction was associated with age (Beta=0.0043; CI:0.0012 - 0.0076; p=0.007), white matter hyperintensity volume (B=0.18; 0.13 - 0.23; p<0.0001) and brain parenchymal fraction (B=0.011; 0.004 - 0.018; p=0.003). At mean follow-up of 3.9 years, 243 in the intensive treatment arm and 199 in the standard treatment arm had evaluable pre and post scans. PVS volume fractions were similar at randomization between treatment groups (1.38% vs 1.39%) but decreased with intensive treatment to 1.35% (p=0.022) while remaining stable with standard treatment (interaction p=0.040). Discussion: Intensive BP treatment reduces the volume of perivascular spaces. These changes may reflect remodeling of waste clearance pathways and/or volume status.