Impact of abnormal nocturnal blood pressure fall on vascular function.

Background: It is well known that nondipping pattern of arterial hypertension has a harmful effect on target organs such as the brain, heart, and kidneys. However, it remains uncertain whether abnormal dipping patterns of nocturnal blood pressure (BP), such as extreme and reverse dipping, influence vascular function.

Methods: This study comprised consecutive 2800 individuals (1554 men and 1246 women). All were nondiabetic and had uncomplicated, untreated essential sustained hypertension based on office measurements. After a 2-week wash-out period, 24-h ambulatory BP recordings were obtained and patients were classified by their nocturnal systolic BP fall (132 extreme dippers with >20% nocturnal systolic BP fall; 1235 dippers with >10% but <20% fall; 1146 nondippers with >0% but <10% fall; and 287 reverse dippers with <0% fall). Microalbumin, ACR (albumin/creatinine ratio), and microglobulin values were measured in all groups.

Results: Extreme dippers did not differ from dippers with regard to microalbumin, microglobulin excretion, or ACR. On the contrary, reverse dippers had significantly (P <.0001) higher values, compared with nondippers, for microalbumin (49.5 v 37.2 mg/dL), microglobulin (10.33 v 8.71 mg/dL), ACR (104.9 v 65.2), and percentages of abnormal values for these parameters.

Conclusions: Microalbuminuria, an index of vascular function, differentiates reverse dippers from nondippers, but not extreme dippers from dippers among hypertensive patients.