Morning pressor surge, blood pressure variability, and arterial stiffness in essential hypertension.

OBJECTIVE

An excess morning blood pressure surge (MBPS) may portend an increased cardiovascular risk, but the mechanisms thereof have been little investigated. The link between MBPS, short-term blood pressure (BP) variability, and arterial stiffness has not been entirely defined.

METHODS

In 602 consecutive untreated hypertensive patients (48 ± 12 years, 61% men, office BP 149/93 ± 17/10 mmHg), we measured carotid-femoral pulse wave velocity (cf-PWV, SphygmoCor) and 24-h ambulatory BP. Using self-reported sleep and wake times, MBPS was defined as sleep-trough (ST-MBPS), prewaking, rising. Short-term BP variability was calculated as weighted 24-h SBP SD and average real variability of 24-h SBP (ARV), that is, average of absolute differences between consecutive SBP readings.

RESULTS

ST-MBPS (r = 0.16, P < 0.001) and rising MBPS (r = 0.12, P = 0.003) showed a direct correlation with cf-PWV, whereas prewaking MBPS had no such relation (r = 0.06, P = 0.14). Only ST-MBPS was independently associated with cf-PWV (t = 1.96, P = 0.04) after adjustment for age, sex, height, office mean arterial pressure, heart rate, and renal function. This association was lost after further adjustment for weighted 24-h SBP SD (P = 0.13) or ARV (P = 0.24). ARV was a significant mediator of the relationship between ST-MBPS and cf-PWV (P = 0.003).

CONCLUSION

In untreated hypertension, ST-MBPS has a direct relation with aortic stiffness, which is mediated by an increased ARV. The adverse effects of MBPS may be partly explained by its link with arterial stiffness, mediated by short-term SBP variability.