Abstract TP477: Vessel Diameter, Brain Perfusion and Small Vessel Disease Burden in HIV+ Population and Controls

Cerebral small vessel disease (CSVD) in patients with HIV is a subject of ongoing study in regard to the effect of HIV infection on cerebral vessels. In our cohort of HIV+ (on stable cART for at least 12 weeks) and age-matched controls, we investigated the relationship between HIV status and extracranial large vessel diameter, burden of white matter hyperintensities (WMH), as well as cerebral blood flow (CBF). Subjects underwent MRI including an arterial spin labeling (ASL) sequence to calculate CBF and MRA to measure arterial diameters. Arterial diameter and regional CBF were used as outcome variables in multivariate regression models incorporating HIV status, hypertension, WMH burden, age, and Reynold score. Partial correlations were performed to assess the relationship strength between CBF and vessel diameter. Extracranial vessel diameter means were significantly different between HIV+ and HIV- cohorts after controlling for age, Reynold score, WMH, hypertension, and regional CBF means. CBF was not significantly different in the presence of HIV, nor WMH. However, hypertension and age were significantly associated with CBF in multivariate regression analysis. Extracranial vessel diameter and WMH were not significantly related. Accounting for HIV status did not affect this correlation. Extracranial large vessel diameter (0.3) and age (0.6) were strongly and significantly partially correlated with CBF. There appears to be a relationship between HIV status and caliber of extracranial vessels, suggesting possible effect of HIV on large vessel health. Vessel diameter and WMH may be related due to similar risk factors, however, further study is needed at this time. As expected, large vessel diameter correlated with perfusion metrics and age. Future directions include a volumetric assessment of WMH and assessments of the relationship between markers of platelets and endothelial dysfunction.