Lack of Correlation Between QTc Dispersion and Morning Blood Pressure Surge in Recently Diagnosed Essential Hypertensive Patients

Valsartan-mediated chronotherapy in spontaneously hypertensive rats via targeting clock gene expression in vascular smooth muscle cells

OBJECTIVE

This study was to investigate the underlying mechanisms of valsartan chronotherapy in regulating blood pressure variability.

METHODS

RT-PCR was used to assay clock genes expression rhythm in the hypothalamus, aortic vessels, and target organs after valsartan chronotherapy. WB was used to measure Period 1 (Per1), Period 2 (Per2) protein expression in aortic vessels, as well as to measure phosphorylation of 20-kDa regulatory myosin light chain (MLC₂₀) in VSMCs.

RESULTS

Specific clock genes in the hypothalamus, and Per1 and Per2 in aorta abdominalis, exhibited disordered circadian expression in vivo. Valsartan asleep time administration (VSA) restored circadian clock gene expression in a tissue- and gene-specific manner. In vitro, VSA was more efficient in blocking angiotensin II relative to VWA, which led to differential circadian rhythms of Per1 and Per2, ultimately corrected MLC₂₀ phosphorylation.

CONCLUSION

VSA may be efficacious in regulating circadian clock genes rhythm, then concomitantly correct circadian blood pressure rhythms.

The relationship between diurnal blood pressure abnormalities and target organ damage in normotensive subjects. Which is more important? Increased blood pressure levels or circadian blood pressure abnormalities

Objective: Circadian blood pressure (CBP) abnormalities are well-known risk factors for many diseases such as cardiovascular, cerebrovascular, and chronic kidney disease. The object of this study was to evaluate the relationship between abnormalities in CBP rhythm and target organ damage (TOD) in normotensive non-dipper (non-DP) subjects.Methods: The 24-h ambulatory BP monitoring (ABPM) and echocardiography were performed and urinary albumin excretion (UAE) was measured in 127 normotensive dipper (DP) (42 males, 85 females) and 337 (89 males, 248 females) normotensive non-DP subjects.Results: When we compared DP and non-DP subjects; Pulse wave velocity (PWV) (7.12 ± 1.72 vs 7.57 ± 1.87 m/s, p = 0.02), the percentile of corrected PWV (cPWV) (7.1 vs. 20.2, p= 0.001) and the percentile of corrected augmentation index (cAIx) (23.5 vs. 33.9, p = 0.03), left ventricle mass index (LVMI) (78.00 ± 23.27 vs. 95.59 ± 18.29 g/m², p = 0.01), relative wall thickness (RWT)(0.36 ± 0.13 vs 0.46 ± 0.09, p = 0.01), percentile of proteinuria (8.6 vs 29.2%, p = 0.00) were higher in non-DP group. In the correlation analyses, the PWV, LVMI, RWT were negatively correlated with the rate of systolic fall in nighttime (%)(-0.15, p = 0.01 vs. -0.23, p = 0.02 vs. -0.27, p = 0.00). It was observed that cPWV, cAIx, and UAE were independently associated with age and non-DP status (NDS), in logistic regression analysis.Conclusions: Our results suggested that normotensive persons with CBP abnormalities had TOD. In light of the data of this article, non-dipper status is detected in the early period and if the provision of diurnal blood pressure rhythm may reduce the incidence of future adverse events in nondipper normotensive subjects.

Resting sympathetic outflow does not predict the morning blood pressure surge in hypertension

OBJECTIVE

The blood pressure (BP) rise on awakening (morning surge) might be a predictor of hypertension-related cardiovascular complications. Previous studies suggest that the autonomic nervous system may contribute to the early morning BP increase. We tested the hypothesis that resting sympathetic outflow [assessed by direct measures of intraneural sympathetic nerve activity (SNA)] may help predict the morning BP surge in hypertension.

METHODS

We measured muscle SNA (MSNA), heart rate (HR) and BP during undisturbed supine rest in 68 newly diagnosed untreated hypertensive patients (53 men and 15 women, age 40 ± 3 years, BMI 27 ± 1 kg/m(2), mean ± SEM). The morning BP surge was defined as the difference between the morning BP and the pre-awake BP.

RESULTS

SBP averaged 143 ± 3 mmHg for daytime and 126 ± 2 mmHg for night-time. Mean HR was 81 ± 2 beats/min for daytime and 69 ± 2 beats/min for night-time. Average MSNA was 32 ± 2 bursts/min., SBP morning surge 19 ± 2 mmHg and HR morning surge 14 ± 2 beats/min. In univariate analysis, MSNA correlated with daytime SBP (r = 0.28, P = 0.02); night-time SBP (r = 0.26, P = 0.03); daytime HR (r = 0.28, P = 0.02); and night-time HR (r = 0.26, P = 0.03). Multivariate analysis, taking into consideration age, BMI and sex, revealed that MSNA was independently related to both daytime (P = 0.006) and night-time HR (P = 0.02), but not to ambulatory SBP. The morning surge of SBP and HR was not related to MSNA (r = 0.01 and r = 0.07, respectively, P = NS).

CONCLUSION

In patients with essential hypertension, MSNA is related to both daytime and night-time HR, but not to the morning BP surge.

Relation between abnormalities in circadian blood pressure rhythm and target organ damage in normotensives

BACKGROUND

To determine the individual effect of abnormalities in blood pressure (BP) circadian rhythm (non-dipping status (NDS), increased morning BP (MBP) or increased MBP surge (MBPS)) on target organ damage (TOD) and which of these is more closely related to TOD in normotensives.

METHODS AND RESULTS

The 24-h ambulatory BP monitoring (ABPM) and echocardiography were performed and urinary albumin excretion (UAE) was measured in 47 dipper (28 women, mean age 45.8 +/- 9.3) and 32 non-dipper (25 women, mean age 49.1 +/- 8.3 years) normotensive subjects. The left ventricular mass index (LVMI) was higher in non-dipper group (103.8 +/- 24.1 vs 91.6 +/- 23.5 g/m2, P=0.03). UAE in non-dipper group was higher, but the difference between the two was not statistically significant (18.9 [10.3, 28.9] vs 14.1 [7.5, 23.8], P=0.11). In multivariate analysis, both LVMI and UAE were affected by NDS and MBP independent of other confounding variables (for LVMI; Coefficient =0.27, P=0.01 and Coefficient =0.37, P=0.001, respectively, and for UAE; Coefficient =0.27, P=0.02 and Coefficient =0.28, P=0.01, respectively).

CONCLUSIONS

It may be postulated that increased night and MBP are the factors that cause TOD, and it seems reasonable to attempt to restore normal diurnal rhythm of the BP even in normotensive subjects.