Relationship between short-term and long-term blood pressure variabilities in essential hypertensives

Sleep characteristics associated with nocturnal blood pressure nondipping in healthy individuals: a systematic review

OBJECTIVE

The current literature investigating nocturnal blood pressure (BP) nondipping has largely focused on clinical populations, however, conditions such as hypertension, obstructive sleep apnoea and insomnia are recognized confounding factors for BP dipping. The exact mechanisms responsible for BP nondipping remain unclear, therefore, there is a need to investigate BP nondipping in healthy individuals to better understand the underlying mechanisms. This review identifies sleep characteristics that may contribute to BP nondipping in healthy individuals. It is anticipated that an understanding of the sleep characteristics that contribute to BP nondipping may inform future sleep-related behavioral interventions to ultimately reducing the burden of cardiovascular disease.

METHODS

The PubMed, Scopus and Web of Science databases were searched for relevant, English language, peer-reviewed publications (from inception to March 2022). The search identified 550 studies. After duplicates were removed, the titles and abstracts of the remaining 306 studies were screened. Of these, 250 studies were excluded leaving 56 studies to test for eligibility. Thirty-nine studies were excluded such that 17 studies fully met the inclusion criteria for the review.

RESULTS

Findings from this review indicate that short sleep duration, more sleep fragmentation, less sleep depth and increased variability in sleep timing may be associated with BP nondipping in healthy individuals.

CONCLUSION

While there is no evidence-based approach for the treatment of nocturnal BP nondipping, it seems promising that addressing one's sleep health may be an important starting point to reduce the prevalence of BP nondipping and perhaps the progression to cardiovascular disease.

Orthostatic hypertension-a new haemodynamic cardiovascular risk factor

Orthostatic hypertension-a condition characterized by a hyperactive pressor response to orthostatic stress-is an emerging risk factor for cardiovascular disease and is associated with hypertensive target-organ damage (resulting in silent cerebrovascular disease, left ventricular hypertrophy, carotid atherosclerosis and/or chronic kidney disease) and cardiovascular events (such as coronary artery disease and lacunar stroke). The condition is also considered to be a form of prehypertension as it precedes hypertension in young, normotensive adults. Orthostatic blood pressure changes can be assessed using orthostatic stress tests, including clinic active standing tests, home blood pressure monitoring and the head-up tilting test. Devices for home and for ambulatory blood pressure monitoring that are equipped with position sensors and do not induce a white-coat effect have increased the sensitivity and specificity of diagnosis of out-of-clinic orthostatic hypertension. Potential major mechanisms of orthostatic hypertension are sympathetic hyperactivity (as a result of hypersensitivity of the cardiopulmonary and arterial baroreceptor reflex) and α-adrenergic hyperactivation. Orthostatic hypertension is also associated with morning blood pressure surge and extreme nocturnal blood pressure dipping, both of which increase the pulsatile haemodynamic stress of central arterial pressure and blood flow in patients with systemic haemodynamic atherothrombotic syndrome.

Genetic and environmental influences on blood pressure variability: a study in twins

OBJECTIVES

Blood pressure variability (BPV) and its reduction in response to antihypertensive treatment are predictors of clinical outcomes; however, little is known about its heritability. In this study, we examined the relative influence of genetic and environmental sources of variance of BPV and the extent to which it may depend on race or sex in young twins.

METHODS

Twins were enrolled from two studies. One study included 703 white twins (308 pairs and 87 singletons) aged 18-34 years, whereas another study included 242 white twins (108 pairs and 26 singletons) and 188 black twins (79 pairs and 30 singletons) aged 12-30 years. BPV was calculated from 24-h ambulatory blood pressure recording.

RESULTS

Twin modeling showed similar results in the separate analysis in both twin studies and in the meta-analysis. Familial aggregation was identified for SBP variability (SBPV) and DBP variability (DBPV) with genetic factors and common environmental factors together accounting for 18-40% and 23-31% of the total variance of SBPV and DBPV, respectively. Unique environmental factors were the largest contributor explaining up to 82-77% of the total variance of SBPV and DBPV. No sex or race difference in BPV variance components was observed. The results remained the same after adjustment for 24-h blood pressure levels.

CONCLUSIONS

The variance in BPV is predominantly determined by unique environment in youth and young adults, although familial aggregation due to additive genetic and/or common environment influences was also identified explaining about 25% of the variance in BPV.

A longitudinal study of blood pressure variability in African-American and European American youth

OBJECTIVES

High blood pressure variability is increasingly used as a predictor of target-organ damage and cardiovascular events. However, little is known about blood pressure variability changes with age and its possible sociodemographic, anthropometric, and genetic moderators.

METHODS

Twenty-four-hour ambulatory blood pressure was measured up to 12 times over a 15-year period in 344 European Americans and 297 African-Americans with an average age of 14 years at the initial visit. Blood pressure variability was indexed by the weighted 24-h standard deviation of ambulatory blood pressure recordings.

RESULTS

Both systolic and diastolic blood pressure variability increased with age and ambulatory blood pressure mean values. Men had higher levels of blood pressure variability (P < 0.001) and showed steeper linear increase rates with age than women. African-Americans showed higher values of blood pressure variability (P < 0.05) than European Americans. Body mass index and waist circumference were also associated with higher blood pressure variability levels (P < 0.001). Individuals with higher father's education level showed lower blood pressure variability. In the full model which included all the above factors, ethnic difference in systolic blood pressure variability was no longer significant.

CONCLUSION

The results of the present study suggest that men and African-Americans have higher blood pressure variability than women and European Americans. Apart from these ethnicity and sex effects, blood pressure variability increases with increases in age (especially in men), ambulatory blood pressure mean values and adiposity as well as decreased socioeconomic status.

Association of an abnormal blood glucose level and morning blood pressure surge in elderly subjects with hypertension

BACKGROUND

We previously reported that morning blood pressure (BP) surge (MBPS) was an independent risk factor for stroke. We evaluated the determinants of MBPS in hypertensive patients.

METHODS

We analyzed 24-h ambulatory BP monitoring (ABPM) records in 458 hypertensive patients (mean: 72.2 +/- 8.5 years). The MBPS was calculated as the mean systolic BP (SBP) over 2 h after waking minus mean SBP during the hour of sleep that included the lowest nighttime BP. The cutoff value for identifying the top decile (the MBPS group) was defined as > or =55 mm Hg.

RESULTS

The MBPS was associated with age, fasting plasma glucose, and 24-h SBP, and they were independent and significant determinants of MBPS in multivariate analysis (age, P = 0.01; fasting plasma glucose, P < 0.01; 24-h SBP, P = 0.04) after adjustment for confounding factors of gender, body mass index (BMI), and smoking status. The subjects in the MBPS group (n = 45) were older in age (76.4 years vs. 71.8 years, P < 0.01) and had higher fasting plasma glucose (97.6 mg/dl vs. 91.4 mg/dl, P = 0.04) than those in the non-MBPS group. In logistic regression analysis, the MBPS group was associated with older age (10 years older: odds ratio (OR) 1.85, 95% confidence interval (CI) 1.26-2.72, P < 0.01) and higher fasting plasma glucose (10-mg/dl increase: OR 1.16, 95% CI 1.01-1.33, P = 0.03).

CONCLUSION

In addition to older age and higher mean 24-h SBP, higher fasting plasma glucose was associated with MBPS.

The ECLIPSE trials: comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension treatment in cardiac surgery patients

BACKGROUND

Acute hypertension during cardiac surgery can be difficult to manage and may adversely affect patient outcomes. Clevidipine is a novel, rapidly acting dihydropyridine L-type calcium channel blocker with an ultrashort half-life that decreases arterial blood pressure (BP). The Evaluation of CLevidipine In the Perioperative Treatment of Hypertension Assessing Safety Events trial (ECLIPSE) was performed to compare the safety and efficacy of clevidipine (CLV) with nitroglycerin (NTG), sodium nitroprusside (SNP), and nicardipine (NIC) in the treatment of perioperative acute hypertension in patients undergoing cardiac surgery.

METHODS

We analyzed data from three prospective, randomized, open-label, parallel comparison studies of CLV to NTG or SNP perioperatively, or NIC postoperatively in patients undergoing cardiac surgery at 61 medical centers. Of the 1964 patients enrolled, 1512 met postrandomization inclusion criteria of requiring acute treatment of hypertension based on clinical criteria. The patients were randomized 1:1 for each of the three parallel comparator treatment groups. The primary outcome was the incidence of death, myocardial infarction, stroke or renal dysfunction at 30 days. Adequacy and precision of BP control was evaluated and is reported as a secondary outcome.

RESULTS

There was no difference in the incidence of myocardial infarction, stroke or renal dysfunction for CLV-treated patients compared with the other treatment groups. There was no difference in mortality rates between the CLV, NTG or NIC groups. Mortality was significantly higher, though, for SNP-treated patients compared with CLV-treated patients (P=0.04). CLV was more effective compared with NTG (P=0.0006) or SNP (P=0.003) in maintaining BP within the prespecified BP range. CLV was equivalent to NIC in keeping patients within a prespecified BP range; however, when BP range was narrowed, CLV was associated with fewer BP excursions beyond these BP limits compared with NIC.

CONCLUSIONS

CLV is a safe and effective treatment for acute hypertension in patients undergoing cardiac surgery.

Comparison of noninvasive oscillometric and intra-arterial blood pressure measurements in hyperacute stroke

OBJECTIVES

This study aims to compare automatic oscillometric blood pressure recordings with simultaneous direct intra-arterial blood pressure measurements in hyperacute stroke patients to test the accuracy of oscillometric readings.

METHODS

A total of 51 first-ever stroke patients underwent simultaneous noninvasive automatic oscillometric and intra-arterial blood pressure monitoring within 3 h of ictus. Casual blood pressure was measured in both arms using a standard mercury sphygmomanometer on hospital admission. Patients who received antihypertensive medication during the blood pressure monitoring were excluded.

RESULTS

The estimation of systolic blood pressure (SBP) using oscillometric recordings underestimated direct radial artery SBP by 9.7 mmHg (95% confidence interval: 6.5-13.0, P<0.001). In contrast, an upward bias of 5.6 mmHg (95% confidence interval: 3.5-7.7, P<0.001) was documented when noninvasive diastolic blood pressure (DBP) recordings were compared with intra-arterial DBP recordings. For SBP and DBP, the Pearson correlation coefficients between noninvasive and intra-arterial recordings were 0.854 and 0.832, respectively. When the study population was stratified according to SBP bands (group A: SBP<or=160 mmHg; group B: SBP>160 mmHg and SBP<or=180 mmHg, group C: SBP>180 mmHg), higher mean DeltaSBP (intra-arterial SBP-oscillometric SBP) levels were documented in group C (+19.8 mmHg, 95% confidence intervals: 12.2-27.4) when compared with groups B (+8.5 mmHg, 95% confidence intervals: 2.7-14.5; P=0.025) and A (+5.9 mmHg, 95% confidence intervals: 1.8-9.9; P=0.002).

CONCLUSION

Noninvasive automatic oscillometric BP measurements underestimate direct SBP recordings and overestimate direct DBP readings in acute stroke. The magnitude of the discrepancy between intra-arterial and oscillometric SBP recordings is even more prominent in patients with critically elevated SBP levels.

Association of eNOS Glu298Asp gene polymorphism with circadian blood pressure rhythm

Hypertensive patients with altered circadian blood pressure (BP) profile experience greater repercussion of hypertension on target organs and a higher risk of cardiovascular events, compared with those with physiological variations in BP. It has been demonstrated in animal models, that circadian variations in BP depend on several regulatory systems, in particular the nitric oxide-cGMP pathway. eNOS298 Glu/Asp polymorphism is a functional variant and may alter the amount of NO generated or eNOS activity. The objective of the present study was to find out whether eNOS298 gene polymorphism affects circadian BP regulation in 110 healthy subjects and 155 never-treated hypertensive patients recruited at Hypertension Units in Grenoble, Toulouse and Lille (France).

Autonomic cardiovascular control and diastolic dysfunction in hypertensive subjects

BACKGROUND

Early hypertension is associated with left ventricular diastolic dysfunction due to increased end-diastolic pressure. This increase, through the cardiopulmonary reflexes, can influence autonomic cardiovascular control.

METHODS

We assessed autonomic nervous system modulation of cardiovascular signals by power spectral analysis of RR interval and systolic arterial pressure variabilities in subjects with recently diagnosed hypertension with or without diastolic dysfunction and in normotensive control subjects.

RESULTS

Both hypertensive groups had higher low-frequency (LF) power expressed in normalized units (NUs) than normotensive controls (p < 0.05; p < 0.001) during controlled breathing at rest. The LF spectral index measured after tilt was greater in hypertensive subjects with diastolic dysfunction than in those without (p < 0.05). LF NUs measured at rest correlated significantly with the E/A wave ratio and after tilt with the E-wave deceleration time.

CONCLUSIONS

These results seem to indicate that in subjects with recently diagnosed hypertension sympathetic modulation of the sinus node prevails. During tilt, a maneuver designed to stimulate systemic arterial and cardiopulmonary baroreceptor reflexes, hypertensive subjects with diastolic dysfunction, who presumably also have higher end-diastolic pressures, seem to have greater sympathetic modulation of the sinus node than hypertensive subjects without diastolic dysfunction.

Hepatocyte growth factor and 24-hour ambulatory blood pressure monitoring

In recent years, many growth factors and cytokines have been shown to be related to arteriosclerosis, and hepatocyte growth factor (HGF) has been reported to be associated with hypertension. In the present study, we investigated the relationship between HGF and hypertension by measuring the serum HGF concentration and performing 24-h ambulatory blood pressure monitoring (ABPM) in 47 randomly selected male and female subjects who underwent a medical examination for cardiovascular disease. The results were as follows. 1) The mean serum HGF concentration in the subjects was 0.35+/-0.14 ng/ml. 2) The serum HGF concentration was positively correlated with both the nighttime systolic and diastolic blood pressures (r=0.42, p<0.05 and r=0.47, p<0.01, respectively). 3) No correlation was found between serum HGF concentration and daytime systolic or diastolic blood pressure. 4) When subjects were divided into two groups based on the difference between daytime and nighttime systolic blood pressure, i.e., a group in which the difference was less than 10 mmHg and a group in which the difference was 10 mmHg or more, the HGF concentration was significantly higher in the former group (0.39+/-0.14 vs. 0.30+/-0.12 ng/ml, p<0.05); similarly, when subjects were divided into a group in which the difference between daytime and nighttime diastolic blood pressure was 5 mmHg and a group in which the difference was 5 mmHg or more, the HGF concentration was significantly higher in the former group (0.42+/-0.15 vs. 0.31+/-0.12 ng/ml, p<0.05). The results indicated that there is a relationship between blood pressure measured by ABPM and serum HGF concentration, and that this relationship might be an index of damage to blood vessels in patients with hypertension.

Cerebrovascular structure and dementia: new drug targets

Effective pharmacological treatment of cognitive disorders in dementia is lacking despite extensive efforts to produce active therapy aimed at neuronal and vascular targets. In this review, the evidence for the involvement of vascular mechanisms in the pathology and evolution of dementia will be examined and the potential importance of age-related changes in cerebrovascular structure and cerebral blood flow (CBF) autoregulation will be discussed. With a description of recent clinical results (on statins, angiotensin-converting enzyme inhibitors and Ca(2+) channel blockers) and experimental results (on beta-amyloid), the impact of drugs on cerebrovascular targets is examined. The working hypothesis that targeting vascular mechanisms in dementia is an option for future therapy is proposed.

Nocturnal non-dipping: what does it augur?

The non-dipping pattern of blood pressure (defined as a nocturnal fall of less than 10%) occurs in about 25% of hypertensives, with increased prevalence in certain sub-groups such as diabetics, African-Americans, and patients with renal disease. It almost certainly has multiple causes, including factors such as the levels of activity and arousal during both the day and the night, the depth and quality of sleep, and the activity of the sympathetic nervous system, among others. In patients with uncomplicated hypertension, the reproducibility is relatively low. There is evidence suggesting that the non-dipping pattern may have an adverse prognosis: thus, it appears to predict the progression of renal disease, to be associated with increased target-organ damage (in some studies), and also to predict increased cardiovascular morbidity. Antihypertensive drug treatment can normalize the non-dipping pattern, but the therapeutic consequences of this are unknown.