Nocturnal blood pressure profiles among normotensive, controlled hypertensive and refractory hypertensive subjects

White matter hyperintensities mediate the association of nocturnal blood pressure with cognition

OBJECTIVE

To test the hypotheses that hypertension and nocturnal blood pressure are related to white matter hyperintensity (WMH) volume, an MRI marker of small vessel cerebrovascular disease, and that WMH burden statistically mediates the association of hypertension and dipping status with memory functioning, we examined the relationship of hypertension and dipping status on WMH volume and neuropsychological test scores in middle-aged and older adults.

METHODS

Participants from the community-based Maracaibo Aging Study received ambulatory 24-hour blood pressure monitoring, structural MRI, and neuropsychological assessment. Four hundred thirty-five participants (mean ± SD age 59 ± 13 years, 71% women) with available ambulatory blood pressure, MRI, and neuropsychological data were included in the analyses. Ambulatory blood pressure was used to define hypertension and dipping status (i.e., dipper, nondipper, and reverse dipper based on night/day blood pressure ratio <0.9, 0.9-1, and >1, respectively). Outcome measures included regional WMH and memory functioning derived from a neuropsychological test battery.

RESULTS

The majority of the participants (59%) were hypertensive. Ten percent were reverse dippers, and 40% were nondippers. Reverse dipping in the presence of hypertension was associated with particularly elevated periventricular WMH volume (F 2,423 = 3.78, p = 0.024) and with lowered memory scores (F 2,423 = 3.911, p = 0.021). Periventricular WMH volume mediated the effect of dipping status and hypertension on memory (β = -4.1, 95% confidence interval -8.7 to -0.2, p < 0.05).

CONCLUSION

Reverse dipping in the presence of hypertension is associated with small vessel cerebrovascular disease, which, in turn, mediates memory functioning. These results point toward reverse dipping as a marker of poor nocturnal blood pressure control, particularly among hypertensive individuals, with potentially pernicious effects on cerebrovascular health and associated cognitive function.

Nondipping Pattern and Cardiovascular and Renal Damage in a Population-Based Study (The STANISLAS Cohort Study)

OBJECTIVE

The attenuation of physiological nocturnal decline of blood pressure (BP)-called nondipper pattern-has previously been reported to be associated with target organ damage in hypertensive subjects. However, this association remains debated and poorly studied in normotensive patients. This study aimed to investigate the association between nondipper pattern and subclinical cardiovascular and renal damage in an initially healthy population-based cohort study.

METHODS

The STANISLAS Cohort is a single-center, familial longitudinal cohort composed of 1,006 families (4,295 subjects) recruited in 1993-1995 for a 5-year periodic health examination. A total of 1,334 subjects from the 4th visit (2011-2016) of the STANISLAS cohort were included. This 4th examination included estimated glomerular filtration rate, albumin/creatinine ratio, pulse wave velocity, central systolic BP, carotid intima-media thickness and distensibility, left ventricular mass index, left ventricular hypertrophy, diastolic dysfunction, and ambulatory blood pressure monitoring (ABPM). Nondipping status was defined as a mean reduction in systolic BP (SBP) or diastolic BP (DBP) lower than 10% during nighttime.

RESULTS

Data were obtained from 798 normotensive subjects (45 ± 14 years, 395 [49%] nondippers, SBP/DBP mmHg 24 hours: 116/71 ± 7/5) and 536 hypertensive patients (56 ± 11 years, 257 [48%] nondippers, SBP/DBP mmHg 24 hours: 127/78 ± 10/7). Mean 24-hour and daytime ABPM measurements were within the normal range, even in hypertensive participants (19% treated). The nondipping pattern was not associated with cardiovascular or renal alterations in this population.

CONCLUSION

In this middle-aged population with an overall 24-hour optimal BP control, the nondipper pattern was not associated with increased cardiovascular or renal damage.

Desoxycorticosterone pivalate-salt treatment leads to non-dipping hypertension in Per1 knockout mice

AIM

Increasing evidence demonstrates that circadian clock proteins are important regulators of physiological functions including blood pressure. An established risk factor for developing cardiovascular disease is the absence of a blood pressure dip during the inactive period. The goal of the present study was to determine the effects of a high salt diet plus mineralocorticoid on PER1-mediated blood pressure regulation in a salt-resistant, normotensive mouse model, C57BL/6J.

METHODS

Blood pressure was measured using radiotelemetry. After control diet, wild-type (WT) and Per1 (KO) knockout mice were given a high salt diet (4% NaCl) and the long-acting mineralocorticoid deoxycorticosterone pivalate. Blood pressure and activity rhythms were analysed to evaluate changes over time.

RESULTS

Blood pressure in WT mice was not affected by a high salt diet plus mineralocorticoid. In contrast, Per1 KO mice exhibited significantly increased mean arterial pressure (MAP) in response to a high salt diet plus mineralocorticoid. The inactive/active phase ratio of MAP in WT mice was unchanged by high salt plus mineralocorticoid treatment. Importantly, this treatment caused Per1 KO mice to lose the expected decrease or 'dip' in blood pressure during the inactive compared to the active phase.

CONCLUSION

Loss of PER1 increased sensitivity to the high salt plus mineralocorticoid treatment. It also resulted in a non-dipper phenotype in this model of salt-sensitive hypertension and provides a unique model of non-dipping. Together, these data support an important role for the circadian clock protein PER1 in the modulation of blood pressure in a high salt/mineralocorticoid model of hypertension.

The effect of renal sympathetic denervation on nocturnal dipping in patients with resistant hypertension; observational data from a tertiary referral centre in the Republic of Ireland

OBJECTIVE

Renal sympathetic denervation (RSD) is an emerging device based treatment for patients with resistant hypertension. Nocturnal dipping (ND) is defined as a decrease in BP of 10-20 % during sleep, and has been shown to be protective against cardiovascular disease. This study examined the effect of RSD on the 24 h BP profile of patients with resistant hypertension.

METHODS AND RESULTS

The first 23 consecutive patients with resistant hypertension scheduled for renal denervation in a single centre were included. 24 h ambulatory blood pressure monitors (ABPM) were given to patients pre-procedure and 9 months post-procedure. RSD led to a statistically non-significant reduction in overall 24 h ABPM BP (150/85 ± 12/9 vs. 143/84 ± 15/11 mmHg; P > 0.05) despite a reduction in the number of antihypertensive medications (4.9 ± 1.2 vs. 4.3 ± 1.2; P = 0.001). There were improvements in systolic ND 1.7 ± 8 vs. 5.2 ± 8 %; P < 0.05), diastolic ND (5.2 ± 8 vs. 10.2 ± 9 %; P < 0.05) and mean arterial pressure (MAP) ND (4.2 ± 8 vs. 8.0 ± 8 %; P < 0.05). Non-significant changes in ND status were observed in systolic (17 vs. 43 % of participants; P > 0.05), diastolic (30 vs. 43 % of participants; P > 0.05) and MAP (22 vs. 39 % of participants; P > 0.05) measurements.

CONCLUSIONS

These data suggest that RSD may lead to an improvement in nocturnal dipping in selected patients with resistant hypertension. This may have cardiovascular benefits even if reduction in BP is not achieved with RSD.

School burnout: increased sympathetic vasomotor tone and attenuated ambulatory diurnal blood pressure variability in young adult women

Two studies examined autonomic and cardiovascular functioning that may link school burnout to cardiovascular risk factors in young healthy adult females. Study 1 (N = 136) investigated whether school burnout was related to resting values of blood pressure (BP) and blood pressure variability (BPV) through laboratory beat-to-beat BP assessment. Study 2 (N = 94) examined the link between school burnout and diurnal BPV through ambulatory BP monitoring. Controlling for anxiety and depressive symptomatology, school burnout demonstrated strong positive relationships with indices of cardiac sympathovagal tone, sympathetic vasomotor tone, inefficient myocardial oxygen consumption, increased 24-h ambulatory heart rate and BP, blunted BP diurnal variability, and increased arterial stiffness. These studies establish cardiovascular biomarkers of school burnout and suggest that even in a seemingly healthy sample school burnout may predispose females to increased cardiovascular risk. Several future lines of research are outlined.

Assessment and management of blood-pressure variability

Blood pressure (BP) is characterized by marked short-term fluctuations occurring within a 24 h period (beat-to-beat, minute-to-minute, hour-to-hour, and day-to-night changes) and also by long-term fluctuations occurring over more-prolonged periods of time (days, weeks, months, seasons, and even years). Rather than representing 'background noise' or a randomly occurring phenomenon, these variations have been shown to be the result of complex interactions between extrinsic environmental and behavioural factors and intrinsic cardiovascular regulatory mechanisms. Although the adverse cardiovascular consequences of hypertension largely depend on absolute BP values, evidence from observational studies and post-hoc analyses of data from clinical trials have indicated that these outcomes might also depend on increased BP variability (BPV). Increased short-term and long-term BPV are associated with the development, progression, and severity of cardiac, vascular, and renal damage and with an increased risk of cardiovascular events and mortality. Of particular interest are the findings from post-hoc analyses of large intervention trials in hypertension, showing that within-patient visit-to-visit BPV is strongly prognostic for cardiovascular morbidity and mortality. This result has prompted discussion on whether antihypertensive treatment should be targeted not only towards reducing mean BP levels but also to stabilizing BPV with the aim of achieving consistent BP control over time, which might favour cardiovascular protection.

The relation between habitual sleep duration and blood pressure values in Japanese male subjects

BACKGROUND

Previous studies have demonstrated that sleep duration is closely associated with metabolic risk factors. However, the relationship between habitual sleep duration and blood pressure values in Japanese population has not been fully established.

METHODS

We performed a cross-sectional study of 1,670 Japanese male subjects to clarify the relationship between habitual sleep duration and blood pressure values. The study subjects were divided into four groups (<6, 6-, 7-, and ≥8 h) according to their nightly habitual sleep duration.

RESULTS

The rate of subjects with <6, 6-, 7-, and ≥8 h sleep duration was 12.0, 37.6, 38.2, and 12.2 %, respectively. Compared with the group with 7-h sleep duration (referent), the <6 and ≥8 h groups had significantly greater systolic and diastolic blood pressure values. The rate of hypertensive subjects, defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, with sleep duration of <6, 6-, 7-, and ≥8 h was 13.4, 5.7, 7.5, and 13.8 %, respectively. Compared with the group with 7-h sleep duration (referent), the multivariate odds ratios (95 % confidence interval) of the groups with <6 and ≥8 h for hypertension was 2.43 (1.40-4.20, P < 0.01) and 2.28 (1.31-3.95, P < 0.01), respectively, adjusted for conventional cardiovascular risk factors.

CONCLUSION

The present study demonstrates that both long and short habitual sleep duration were significantly associated with high blood pressure values and hypertension occurrence in Japanese male subjects.

Effects of dipping and psychological traits on morning surge in blood pressure in healthy people

Despite the role of anxiety, depression and hostility in the pathogenesis of cardiovascular diseases, their impact on two significant cardiovascular risk factors, nocturnal dipping and morning surge in blood pressure (MSBP), are largely ignored and primarily studied in clinical populations. This study examined the effects of dipping and psychological traits on MSBP in healthy people. Nocturnal dipping and MSBP were derived from 24-h ambulatory BP obtained in 77 men and 79 women, mean age 32.8 (s.d.: 7.4). Differences in depression, anxiety and hostility were examined by questionnaires. Higher levels of dipping (P<0.0001) and depressive symptoms (P=0.01) independently contributed to increased MSBP. Dipping interacts with depression (P=0.04), hostility (P=0.01) and anxiety (P=0.04) in determining MSBP. Low dippers with higher scores on the psychological traits showed higher MSBP than high dippers. A significant MSBP interaction was found between sex and depressive symptoms (P=0.05), anxiety (P<0.0001) and hostility (P=0.01) with higher scores associated with increased MSBP observed in males. Findings underscore depression as a predictor of MSBP independent of dipping. The clinically significant relationship between dipping and non-dipping patters, psychological traits and MSBP requires further investigation.

Ambulatory blood pressure monitoring in resistant hypertension

ABPM constitutes a valuable tool in the diagnosis of RH. The identification of white coat RH and masked hypertension (which may fulfill or not the definition of RH) is of great importance in the clinical management of such patients. Moreover, the various ABPM components such as average BP values, circadian BP variability patterns, and ambulatory BP-derived indices, such as ambulatory arterial stiffness index (AASI), add significantly to the risk stratification of RH. Lastly, ABPM may indicate the need for implementation of specific therapeutic strategies, such as chronotherapy, that is, administration-time dependent therapy, and the evaluation of their efficacy.

Can nocturnal hypertension predict cardiovascular risk?

Nocturnal hypertension and non-dipping of blood pressure during sleep are distinct entities that often occur together and are regarded as important harbingers of poor cardiovascular prognosis. This review addresses several aspects related to these blood pressure abnormalities including definitions, diagnostic limitations, pathogenesis and associated patient profiles, prognostic significance, and therapeutic strategies. Taken together, persistent nocturnal hypertension and non-dipping blood pressure pattern, perhaps secondary to abnormal renal sodium handling and/or altered nocturnal sympathovagal balance, are strongly associated with deaths, cardiovascular events, and progressive loss of renal function, independent of daytime and 24-hour blood pressure. Several pharmacological and non-pharmacological approaches may restore nocturnal blood pressure and circadian blood pressure rhythm to normal; however, whether this translates to a clinically meaningful reduction in unfavorable cardiovascular and renal consequences remains to be seen.