The average of multiple blood pressure (BP) readings (mean BP) independently predicts target organ damage (TOD). Observational studies have also shown an independent relationship between BP variability (BPV) and TOD, but there is limited longitudinal data. This study aimed to determine the effects of changes in mean BP levels compared with BPV on left ventricular mass index (LVMI) and aortic pulse wave velocity (aPWV).METHODS
Mean BP levels (research-protocol clinic BP (clinic BP), 24-hour ambulatory BP, and 7-day home BP) and BPV were assessed in 286 patients with uncomplicated hypertension (mean age 64±8 SD years, 53% women) over 12 months. Reading-to-reading BPV (from 24-hour ambulatory BP) and day-to-day BPV (from 7-day home BP) were assessed at baseline and 12 months, and visit-to-visit BPV (clinic BP) was assessed from 5 visits over 12 months. LVMI was measured by 3D echocardiography and aPWV with applanation tonometry.RESULTS
The strongest predictors of the changes in LVMI (ΔLVMI) were the changes in mean 24-hour systolic BPs (SBPs) (P < 0.02). Similarly, the strongest predictors of the changes in aPWV (ΔaPWV) were the changes in mean 24-hour ambulatory SBPs (P < 0.01) and the changes in mean clinic SBP (P < 0.001). However, none of the changes in BPV were independently associated with ΔLVMI or ΔaPWV (P > 0.05 for all).CONCLUSIONS
Changes in mean BP levels, but not BPV, were most relevant to changes in TOD in patients with uncomplicated hypertension. Thus, from this point of view, BPV appears to have limited clinical utility in this patient population.