Nighttime Blood Pressure and New-Onset Left Ventricular Hypertrophy

The relationship between circadian blood pressure (BP) variations and the extent of subclinical cardiac organ damage is still debated. In a general population, we investigated the association of night-to-day BP fall, as well as nocturnal BP level (mean and lowest values), with left ventricular (LV) hypertrophy and the value of both BP parameters in predicting new-onset LV hypertrophy. Office BP, 24-hour ambulatory BP values, and laboratory investigations were assessed on entry in 1682 subjects (50.2% men; mean age, 50.2±13.7 years) of the Pressioni Arteriose Monitorate E Loro Associazioni. Echocardiographic LV mass was measured at the initial evaluation and 10 years later. Multiple regression analyses, including daytime systolic BP (SBP), age, sex, and body mass index, showed that the lowest SBP level and the extent of nocturnal SBP decline were independently related to baseline LV mass. After adjustment for several confounders, both mean nocturnal SBP (relative risk for each 10-mm Hg increase in SBP, 1.15; 95% confidence interval, 1.01-1.23; P<0.0001) and the lowest SBP level (relative risk for each 10-mm Hg increase in SBP, 1.10; 95% confidence interval, 1.02-1.19; P=0.01) were independent predictors of new-onset LV hypertrophy. This was not the case for the magnitude of nighttime SBP fall (hazard ratio for each 10% decrease in SBP, 0.91; 95% confidence interval, 0.80-1.04; P=0.18). In a general population, nighttime BP level rather than the nocturnal BP decline may be regarded as a reliable parameter for predicting the development of LV hypertrophy in subjects with normal LV mass. This finding may have important implications for optimizing cardiovascular prevention in the general population.