Antihypertensive drug classes, not blood pressure, are associated with cerebral perfusion. Results from the PREvention of Dementia by Intensive VAscular care (PREDIVA) study

Background: Constant cerebral blood flow (CBF) is fundamental to cerebral function. With aging and chronic hypertension, arteriolar damage may disrupt the CBF autoregulatory capacity. This might cause CBF to fluctuate with blood pressure (BP) levels, low BP and antihypertensive medication (AHM), potentially evoking hypoperfusion. We investigated the cross-sectional and longitudinal relations of BP and AHM with cerebral perfusion using arterial spin labeling (ASL).
Methods: In 186 community-dwelling individuals with hypertension (77±3 years, 53% female), 125 (67%) with 3-year follow-up (Figure 1), we assessed grey matter (GM) and white matter (WM) CBF (ml/100g/min) and the spatial coefficient of variation (CoV; SD CBF/mean CBF). Cross-sectional associations were assessed combining baseline and follow-up data using mixed models, longitudinal associations using linear regression assessing change, adjusted for baseline. We additionally adjusted for age, sex, AHM, stroke and parenchymal fraction.
Results: Cross-sectionally, higher diastolic BP was associated with lower GM and WM CBF (Table 1). AHM were associated with lower GM CBF and higher spatial CoV. Since calcium channel blockers (CCB) and angiotensin receptor blockers (ARB) in our main study were specifically associated with lower dementia risk compared to other AHM, we assessed these separately. Other AHM were associated with lower GM and WM CBF, while CCBs and ARBs were not. There were no correlations between BP change and perfusion changes (Table 2). We observed no J-shaped relationships.
Discussion: We found no evidence for any direct relation between BP and cerebral perfusion. Possibly, higher diastolic BP was associated with lower CBF by being a marker of more severe long-standing hypertension evoking vascular damage. Our finding that ARBs and CCBs are relatively protective of CBF compared to other AHM is consistent with findings of a protective effect of these AHM classes on dementia incidence, and could influence future treatment.