Associations between nondipping of nocturnal blood pressure decrease and cardiovascular target organ damage in strictly selected community-dwelling normotensives

Background: In hypertensives, nondippers are more likely than dippers to suffer silent, as well as overt, hypertensive target organ damage. In this study, we investigated whether a nondipper status was associated with target organ damage in normotensives. Methods: We performed ambulatory blood pressure (BP) monitoring, echocardiography, and carotid ultrasonography and measured natriuretic peptides and urinary albumin (UAE) in 74 normotensive subjects with the following criteria: 1) clinical BP <140/90 mm. Hg; 2) average 24-h ambulatory BP <125/80 mm Hg. Results: The left ventricular mass index (LVMI) and the relative wall thickness (RWT) measured by echocardiography, were greater in nondippers than dippers (LVMI: 103 +/- 26 v 118 +/- 34 g/m(2), P < .05; RWT: 0.38 +/- 0.07 v 0.43 +/- 0.09, P < .01). Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were higher in nondippers than dippers (ANP: 14 +/- 10 v 36 +/- 63 pg/mL, P < .01; BNP: 16 +/- 12 v 62 +/- 153 pg/mL, P < .05). There were no significant differences in UAE and intima-media thickness measured by carotid ultrasonography. Conclusions: Normotensive nondipping may not reflect renal damage, but may have a predominant effect on cardiac damage. Nondipping of nocturnal BP seems to be a determinant of cardiac hypertrophy and remodeling, and may result in a cardiovascular risk independent of ambulatory BP levels in normotensives. Am J Hypertens 2003; 16:434-43 8 (C) 2003 American Journal of Hypertension, Ltd.