Abstract 9012: Comparison of Clinic and Ambulatory Blood Pressure Variability as Predictors for Cardiovascular Events in Patients with Hypertension
Background: Clinic blood pressure variability (BPV) has been shown to be a prognostic indicator in hypertensive patients. However, it is not known if clinic BPV is superior to ambulatory blood pressure (ABP) variability in predicting cardiovascular disease (CVD).
Methods: We performed ABP monitoring in 457 hypertensives. The clinic BP readings during follow up were picked up from the medical records, and calculated as the means or standard deviations (SDs). The mean age of the subjects was 67.0 ± 9.2 years, and they were followed for 66 ± 27 months. Stroke, myocardial infarction, and sudden cardiac death were defined as Hard CVD events, and these plus angina, heart failure, and other CVD were defined as All CVD events. Cox regression analyses were performed with adjustment for significant covariates.
Results: As shown in the Figures, increased clinic BPV was associated with All CVD events, while increased sleep BPV was associated with Hard CVD events. In multivariable analyses, SD in clinic BP was an independent predictor for All CVD events (P=0.008), even when the SD in awake SBP or sleep SBP was entered in the same model. On the other hand, SD in sleep SBP (P=0.04), but not SD in awake SBP (P=0.23), was an independent predictor for Hard CVD events when they were entered with SD in clinic SBP (P=0.20) in the same model. With regard to mean BP, both ambulatory and clinic mean SBP predicted All CVD events, but the predictability of mean awake SBP (P=0.02) and mean sleep SBP (P=0.008) were better than that of mean clinic SBP (P=0.11 and 0.09, respectively).
Conclusions: Clinic BPV was better than ambulatory BPV in predicting All cardiovascular events including angina and heart failure, but ambulatory BPV was better in the case of Hard outcomes. These findings suggest that each BPV measure can be separately used for the prediction of cardiovascular outcomes.
- © 2011 by American Heart Association, Inc.