Nocturnal hypertension and organ damage in dippers and nondippers

Background The relationship between high nocturnal blood pressure (BP), organ damage and the dipping/nondipping status is poorly defined. We investigated whether a consistent dipping/nondipping pattern defined on the basis of two 24-h ambulatory BP monitorings (ABPMs) is associated with subclinical organ damage in untreated hypertensive patients with elevated nighttime BP. Methods All subjects underwent the following procedures cardiac and carotid ultrasonography, 24-h urine collection for microalbuminuria (MA), and ABPM over two 24-h periods within 4 weeks. Nocturnal hypertension was defined according to current guidelines (i.e., nighttime systolic BP (SBP) ≤120 and/or diastolic BP ≤70 mm Hg) and nondipping status as an average reduction in SBP at night >10% compared with day-time values. Results Among 343 subjects, 199 were dippers and 144 nondippers. No differences were found in clinical variables, average 48-h BP, left ventricular mass, carotid intima-media (IM) and urinary albumin excretion between the groups. This was also the case for prevalence rates of left ventricular hypertrophy, carotid IM thickening or plaque and MA. Finally, no relationship was found between the markers of organ damage and BP fall at night. Conclusions In the presence of nocturnal hypertension, dippers have a similar subclinical cardiac and extra-cardiac organ damage as their nondipper counterparts. These data suggest that therapeutic strategies only addressing the nondipper pattern may be insufficient to protect hypertensive subjects against the dangerous effects of elevated nocturnal BP.