INCREASING THE SLEEP-TIME RELATIVE BLOOD PRESSURE DECLINE TOWARDS A MORE DIPPING PATTERN REDUCES CARDIOVASCULAR RISK: RESULTS OF THE MAPEC STUDY: PP.16.83

Abstract

Objectives: Independent studies have concluded that non-dipping and an elevated asleep blood pressure (BP) are relevant predictors of cardiovascular risk. The potential reduction in cardiovascular risk associated with increasing the dipping of the BP pattern has never been evaluated and is still a matter of debate. The MAPEC study was designed to investigate whether normalization of the circadian BP profile towards a more dipper pattern by increasing the sleep-time relative BP decline results in reduced cardiovascular risk. Methods: This prospective study investigated 3344 subjects (1718 men), 52.6 ± 14.5 years of age. At inclusion, 649 subjects were normotensive and 2695 were hypertensive. At baseline, BP was measured by ambulatory monitoring (ABPM) every 20-min from 07:00 to 23:00 h and every 30-min at night for 48 h. ABPM was scheduled yearly or more frequently (quarterly) if treatment adjustment was required to improve BP control. The Cox proportional-hazard model was used to estimate relative risks of cardiovascular events associated to changes in sleep-time relative BP decline and other ABPM parameters. Results: The median time of follow-up was 5.6 years. Based on either the single first or the last available ABPM profile from each subject, the sleep-time relative BP decline and the asleep BP mean were the best joint predictors of cardiovascular risk in a Cox proportional-hazard model adjusted for sex, age, diabetes, antihypertensive treatment, and clinic BP. When data were analyzed on the basis of changes in BP during follow-up, decreased cardiovascular risk was significantly associated with progressive increase in sleep-time relative systolic BP decline (P < 0.001). The increased event-free survival associated with normalizing the BP pattern was significant whether ambulatory BP level was at the normotensive or at the hypertensive range. Conclusions: The sleep-time relative BP decline is a prognostic marker of cardiovascular morbidity and mortality, independent from 24 h BP mean. Most important, increasing this relative decline towards a more dipping pattern decreases cardiovascular risk at all BP levels, even within the normotensive range.