Blood pressure nondippers exhibited a significantly attenuated decrease in systemic vascular resistance from daytime to night-time compared with dippers (7.8% vs. 16.1%, P<0.001).
Observational (n=140)
Is blood pressure nondipping associated with a blunted night-time reduction in systemic vascular resistance in patients with elevated blood pressure?
Blunted night-time blood pressure dipping is associated with impaired systemic vasodilation during sleep, particularly among African-Americans, suggesting it may be a marker of more advanced vascular disease.
Absolute Event Rate: 7.8% vs 16.1%
p-value: p=<0.001
OBJECTIVE: The 'nondipping' pattern of circadian blood pressure (BP) variation is an established independent predictor of adverse cardiovascular outcomes. Although this phenomenon has been widely studied, its underlying circadian hemodynamics of cardiac output and systemic vascular resistance (SVR) have not been well characterized. We evaluated the hypothesis that BP nondipping would be associated with a blunted night-time reduction in SVR in a biracial sample of 140 (63 African-American and 77 white) men and women with elevated clinic BP (130-159/85-99 mmHg). METHODS AND RESULTS: Twenty-four-hour ambulatory hemodynamics were assessed using standard ambulatory BP monitoring coupled with synchronized ambulatory impedance cardiography. Using the criterion of less than 10% dip in SBP, there were 51 nondippers (SBP dip = 7.3 ± 2.6%) and 89 dippers (SBP dip = 15.5 ± 3.4%). There was minimal change in cardiac output from daytime to night-time in both dippers and nondippers. However, SVR decreased from daytime to night-time, but nondippers compared with dippers exhibited a significantly attenuated decrease in SVR from daytime to night-time (7.8 vs. 16.1%, P < 0.001). Relative to their white counterparts, African-Americans also exhibited blunted SBP dipping (10.9 vs. 14.6%, P < 0.001) as well as an attenuated decrease in SVR (10.8 vs. 15.6%, P < 0.001). CONCLUSION: Overall, these findings indicate that blunted night-time BP dipping is associated with impairment of the systemic vasodilation that is characteristic of the night-time sleep period and is especially prominent among African-Americans. In the context of high BP, these findings suggest that nondipping may be a manifestation, or marker, of more advanced vascular disease.
Sherwood et al. (Mon,) conducted a observational in Elevated blood pressure (n=140). Blood pressure nondipping vs. Blood pressure dipping was evaluated on Decrease in systemic vascular resistance (SVR) from daytime to night-time (p=<0.001). Blood pressure nondippers exhibited a significantly attenuated decrease in systemic vascular resistance from daytime to night-time compared with dippers (7.8% vs. 16.1%, P<0.001).
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