Ambulatory blood pressure monitoring after 1 year on valsartan or amlodipine-based treatment: a VALUE substudy

Objective The ambulatory blood pressure (ABP) monitoring substudy of the Valsartan Anti hypertensive Long-term Use Evaluation (VALUE) trial was carried out in a subset of patients from USA, Italy and Denmark. ABP was measured after 1 year in the trial, with the aim of evaluating comparability of ABP levels on valsartan (VAL) and amlodipine (AML)-based regimens. Methods ABP was measured every 20 min during a 25-h period after morning administration of medicine; 659 patients were available for intention-to-treat analysis. Results Office blood pressure (BP) differences were smaller than in the main study and mean ABP levels also showed only minor differences between the two regimens (VAL, 132.5/74.8 mmHg; AML, 131.5/75.2 mmHg). However, during the first 7 h after dosing, ABP was lower on VAL, whereas AML exerted a significantly stronger effect during the last 4 h of the dosing interval - possibly influencing the differences in office BP found in the main study. Mean heart rate (HR) was higher on AML (72.3 bpm) than on VAL (70.5 bpm) (P=0.013), suggesting a sustained difference in sympathetic activation. Correlation analysis showed a close relationship between treated ABP levels and the occurrence of combined cardiovascular endpoints - superior to the relationship to office BP. Conclusions In these elderly high-risk patients, diastolic ABP levels tended to be less predictive than systolic, and daytime less predictive than night-time for all cardiovascular endpoints. The findings underline the importance of ABP substudies in comparative trials for elucidating significant differences in pharmacodynamics, and stresses the superior predictive power of ABP.