Blunted Reduction of Pulse Pressure during Nighttime Is Associated with Left Ventricular Hypertrophy in Elderly Hypertensive Patients

Abstract

Increased pulse pressure (PP) is recognized as a risk factor for cardiovascular disease, especially in elderly patients. However, blood pressure (BP) is known to have a circadian variation. Therefore, this study asked whether or not PP has a circadian variation and, if so, whether a circadian variation of PP has clinical importance. Ambulatory BP monitoring (every 30 min for 48 h) was performed in 255 patients with untreated essential hypertension (24 to 82 years old; mean: 52+/-12 years). Left ventricular mass index (LVMI) was estimated from M-mode echocardiography. PP was decreased during nighttime (10+/-11% reduction from daytime PP). Multivariate linear regression analysis showed that, among four variables-the degree of nighttime PP reduction, daytime PP, 48-h systolic BP, and nondipper hypertension-the degree of nighttime PP reduction had the strongest (inverse) correlation with LVMI in a subgroup of elderly patients (> or =60 years old, n =67) (standardized regression coefficient=-0.32, p =0.02), whereas this association was not significant in the whole patient population unclassified by age. Furthermore, a blunted reduction of nighttime PP in combination with nondipper hypertension was an incremental risk for increase in LVMI in the elderly patients. In conclusion, PP is reduced during nighttime, but the degree of reduction varies among patients. The blunted reduction of nighttime PP is a risk for left ventricular hypertrophy, an established predictor of hypertension-induced cardiovascular events, and it may thus play a role in cardiovascular complications, especially in elderly patients with nondipper hypertension.