Impact of the time rate of blood pressure variation on left ventricular mass

Blood pressure variability in children with obesity and sleep-disordered breathing following positive airway pressure treatment

Obese youth with sleep-disordered breathing are treated with positive airway pressure to improve sleep and cardiovascular status. While improvements in sleep parameters have been confirmed, a study by Katz et al. showed no major improvement in ambulatory blood pressure. The aim of this ancillary study was to analyze short-term blood pressure variability, following positive airway pressure treatment, as a more sensitive marker of cardiovascular health. We analyzed 24-h blood pressure variability data in 17 children, taken at baseline and after 12 months of treatment. These data were derived from an already published prospective, multicenter cohort study conducted in 27 youth (8-16 years) with obesity who were prescribed 1-year of positive airway pressure for moderate-severe sleep-disordered breathing. Significant decreases were found in 24 h systolic blood pressure (p = 0.040) and nighttime diastolic blood pressure (p = 0.041) average real variability, and diastolic blood pressure (p = 0.035) weighted standard deviation. Significant decreases were noted in nighttime diastolic blood pressure time rate variability (p = 0.007). Positive airway pressure treatment resulted in a significant decrease in blood pressure variability, suggesting a clinically significant improvement of sympathetic nerve activity in youth with obesity and sleep-disordered breathing. IMPACT: Cardiovascular variability, as measured by blood pressure variability, is improved in children following positive airway pressure treatment. Our novel findings of improved blood pressure time rate variability are the first described in the pediatric literature. Future studies aimed at analyzing target organ damage in this patient population will allow for a better understanding as to whether alterations in blood pressure variability translate to decreasing target organ damage in children, as seen in adults.

Blood pressure and its variability: classic and novel measurement techniques

Current hypertension guidelines recommend using the average values of several blood pressure (BP) readings obtained both in and out of the office for the diagnosis and management of hypertension. In-office BP measurement using an upper-arm cuff constitutes the evidence-based reference method for current BP classification and treatment targets. However, out-of-office BP evaluation using 24 h ambulatory or home BP monitoring is recommended by all major medical associations for obtaining further insights into the BP profile of an individual and how it relates to their daily activities. Importantly, the highly variable nature of office and out-of-office BP readings has been widely acknowledged, including the association of BP variability with cardiovascular outcomes. However, to date, the implications of BP variability on cardiovascular outcomes have largely been ignored, with limited application in clinical practice. Novel cuffless wearable technologies might provide a detailed assessment of the 24 h BP profile and behaviour over weeks or months. These devices offer many advantages for researchers and patients compared with traditional BP monitors, but their accuracy and utility remain uncertain. In this Review, we outline and compare conventional and novel methods and techniques for assessing average BP levels and BP variability, and reflect on the utility and potential of these methods for improving the treatment and management of patients with hypertension.

The most commonly available blood pressure (BP) monitoring devices are useful for capturing a snapshot BP value, but most have limited utility in measuring BP variability. In this Review, Schutte and colleagues outline the advantages and disadvantages of conventional and novel techniques to measure average BP levels and BP variability.

Although the dynamic nature of blood pressure (BP) is well-known, hypertension guidelines recommend using the average values of static BP readings (office or out-of-office), specifically aiming to level the fluctuations and peaks in BP readings.

All current BP measurement methods have imperfect reproducibility owing to the continuous fluctuation in BP readings, making it difficult to accurately diagnose hypertension.

Accumulating evidence from clinical trials, large registries and meta-analyses shows that increased BP variability predicts cardiovascular outcome, independently of the average BP values.

To date, BP variability is overlooked, with limited application in clinical practice, probably owing to a variety of complex non-standardized BP variability assessment methods and indices, and uncertain thresholds and clinical usefulness.

Novel cuffless wearable BP technologies can provide very large numbers of readings for days and months without the discomfort of traditional BP monitoring devices, and have the potential to replace current BP methods, once accuracy issues are resolved and their clinical usefulness is proved.

Hydration status and blood pressure variability in primary hypertensive patients

BACKGROUND

Increased blood pressure variability (BPV) is associated with higher cardiovascular risk. The association between BPV and fluid status in hypertensive patients has not been investigated so far. The aim of the present study was to determine the contribution of fluid balance to BPV and impact on endothelial and cardiac functions among primary hypertensive patients.

METHODS

This is a prospective interventional study conducted in primary hypertensive patients with one-year follow-up. Volume status measurements by a body composition monitor, ambulatory blood pressure (BP) monitoring, echocardiographic and carotid intima-media thickness (CIMT) measurements were performed at enrollment and at twelfth. Patients in one of the two groups were kept negative hydrated during trial with diuretic treatment. Patients in other group were positively hydrated (hypervolemic) at enrollment, antihypertensive drugs other than diuretics (vasodilator agents) were added or intensified according to the BP monitoring. Average real variability (ARV) index was used for establishing the prognostic significance of BPV.

RESULTS

The study population consisted of 50 patients with a mean age of 54.5±8.8 years. At the end of one-year follow-up, patients in negative hydrated group were found to have significantly lower BP, CIMT, left ventricle mass index (LVMI) and systolic and diastolic ARV. More weight gain and higher systolic BP were major risk factors of high systolic ARV. Patients who have improvement in CIMT and LVMI were considered as target organ damage (TOD) recovery present. In negatively hydrated group, TOD significantly reduced during trial. In patients who have TOD recovery, BPV significantly more reduced like systolic and diastolic BP. Significant risk factors associated with the presence of TOD were 24h systolic BP and daytime and night time diastolic ARV and night time diastolic BP.

CONCLUSION

Addition of diuretic to established treatment or intensified diuretic treatment and keeping patients in negative hydration status resulted in reduction in BPV at twelfth month of follow-up. More weight gain and higher systolic BP are major risk factors of high systolic ARV, but not hypervolemia. BPV, especially diastolic ARV, was significantly associated with TOD.

Clinical implications of blood pressure variability (BPV) in pregnancies: a review

Background Hypertension disorder in pregnancy (HDP) is the second most common contributor to maternal morbidity and mortality worldwide. Blood pressure variability (BPV), with the assistance of ambulatory blood pressure monitoring (ABPM), measures blood pressure readings in pregnant women and has the potential to predict the occurrence of pregnancy-induced hypertension (PIH) or preeclampsia (PE) before any symptoms develop. Methodology Studies involving ABPM among pregnant women were identified using electronic databases such as PubMed, Scopus, Google Scholar, ScienceDirect, Medscape, Ovid and ProQuest. These electronic databases were assessed from 1990 to 2018. Keywords used to search for literatures included a combination of BPV matched with pregnancy, pregnant women and HDP, gestational hypertension and/or PE. Results Out of 21,526 articles identified, a total of 10 studies met the criteria. Seven articles used the spectral analysis method while another two articles used a combination of spectral analysis, time domain and a non-linear method for BPV analysis. The final article described BPV as vagal baroreflex. Four articles agreed that high frequency (HF) BPV was mainly dominant from the second trimester until 4 days postpartum in HDP patients. This reflects the dominant features of parasympathetic activities among these patients. Two articles that used time domain also agreed that standard deviation (SD) BPV increased in PE patients. Conclusions In pregnancy, BPV has a strong impact on the knowledge understanding of the disease in clinical fields, allows a superior ability to predict PIH and PE in mid-pregnancy and offers potential value for addressing hypertension in pregnancy.

Blood pressure variability estimated by ARV is a predictor of poor short-term outcomes in a prospective cohort of minor ischemic stroke

Prior studies have shown that patients with minor ischemic stroke have substantial disability rates at hospital discharge. We sought to determine whether blood pressure variability (BPV) estimated by average real variability (ARV) is one of the predictors of poor outcome at 90 days. Four hundred fifty-one consecutive patients with ischemic stroke treated within 7 days after onset were enrolled prospectively. Baseline magnetic resonance imaging (MRI) was performed on all subjects. Blood pressure was measured for all recruited patients every 2 hours in the first 24 hours after admission, followed by measurements collected every 4 hours from day 2 to day 7 after admission. ARV was used to estimate BPV. A total of 192 patients with minor ischemic stroke were enrolled, and 11 of them (5.7%) had poor outcomes. Univariate regression analysis showed that early neurological deterioration (X² = 21.44, P = 0.000), severe symptomatic large artery stenosis or occlusion (X² = 9.260, P = 0.000), large artery atherosclerotic stroke (X² = 7.14, P = 0.002), total cholesterol (TC), and D2-7 SBP-ARV (t = 5.449, P = 0.001) of the poor outcome group were significantly higher than those of the good outcome group. Multivariate logistic regression analysis showed that early neurological deterioration (OR 4.369, 95% CI 3.54, 15.65; P = 0.001), severe symptomatic large artery stenosis or occlusion (OR 5.56, 95% CI 3.56, 13.65; P = 0.000), large artery atherosclerotic stroke (OR 3.56, 95% CI 1.45, 7.48; P = 0.004), and D2-7 SBP-ARV (OR 3.96, 95% CI 1.90, 20.18, P = 0.008) were significantly related to poor outcomes. In conclusion, approximately 5.7% of minor ischemic stroke patients had poor outcomes. D2-7 SBP-ARV, early neurologic deterioration, severe symptomatic artery stenosis or occlusion, and large atherosclerotic stroke were the independent risk factors of poor short-term outcomes.

Brain Oscillations Elicited by the Cold Pressor Test: A Putative Index of Untreated Essential Hypertension

Objective

Essential hypertension is associated with reduced pain sensitivity of unclear aetiology. This study explores this issue using the Cold Pressor Test (CPT), a reliable pain/stress model, comparing CPT-related EEG activity in first episode hypertensives and controls.

Method

22 untreated hypertensives and 18 matched normotensives underwent 24-hour ambulatory blood pressure monitoring (ABPM). EEG recordings were taken before, during, and after CPT exposure.

Results

Significant group differences in CPT-induced EEG oscillations were covaried with the most robust cardiovascular differentiators by means of a Canonical Analysis. Positive correlations were noted between ABPM variables and Delta (1–4 Hz) oscillations during the tolerance phase; in high-alpha (10–12 Hz) oscillations during the stress unit and posttest phase; and in low-alpha (8–10 Hz) oscillations during CPT phases overall. Negative correlations were found between ABPM variables and Beta2 oscillations (16.5–20 Hz) during the posttest phase and Gamma (28.5–45 Hz) oscillations during the CPT phases overall. These relationships were localised at several sites across the cerebral hemispheres with predominance in the right hemisphere and left frontal lobe.

Conclusions

These findings provide a starting point for increasing our understanding of the complex relationships between cerebral activation and cardiovascular functioning involved in regulating blood pressure changes.

Associations of blood pressure variability and retinal arteriolar diameter in participants with type 2 diabetes

Blood pressure variability is associated with macrovascular complications and stroke, but its association with the microcirculation in type II diabetes has not been assessed. This study aimed to determine the relationship between blood pressure variability indices and retinal arteriolar diameter in non-diabetic and type II diabetes participants. Digitized retinal images were analysed to quantify arteriolar diameters in 35 non-diabetic (aged 52 ± 11 years; 49% male) and 28 type II diabetes (aged 61 ± 9 years; 50% male) participants. Blood pressure variability was derived from 24-h ambulatory blood pressure. Arteriolar diameter was positively associated with daytime rate of systolic blood pressure variation (p = 0.04) among type II diabetes participants and negatively among non-diabetics (p = 0.008; interaction p = 0.001). This finding was maintained after adjusting for age, sex, body mass index and mean daytime systolic blood pressure. These findings suggest that the blood pressure variability-related mechanisms underlying retinal vascular disease may differ between people with and without type II diabetes.

Higher Blood Pressure Variability in White Coat Hypertension; from the Korean Ambulatory Blood Pressure Monitoring Registry

BACKGROUND AND OBJECTIVES

Blood pressure variability (BPV) was recently shown to be a risk factor of stroke. White coat hypertension (WCH) used to be regarded as innocuous, but one long-term follow-up study reported that WCH increased stroke rate compared to normotension (NT). In this study, we aimed to evaluate the relationship between WCH and BPV.

SUBJECTS AND METHODS

We analyzed 1398 subjects from the Korean Ambulatory Blood Pressure Registry, who were divided into NT (n=364), masked hypertension (n=122), white coat hypertension (n=254), and sustained hypertension (n=658) groups.

RESULTS

Baseline characteristics were similar among groups. The average real variability (ARV), a highly sensitive BPV parameter, was highest in the WCH group, followed by the sustained hypertension, masked hypertension, and NT groups. The results persisted after being adjusted for covariates. The WCH vs. sustained hypertension results (adjusted mean±standard error) were as follows: 24-h systolic ARV, 22.9±0.8 vs. 19.4±0.6; 24-h diastolic ARV, 16.8±0.6 vs. 14.3±0.5; daytime systolic ARV, 21.8±0.8 vs. 16.8±0.6; and daytime diastolic ARV, 16.2±0.6 vs. 13.4±0.5 (p<0.001 for all comparisons).

CONCLUSION

From the registry data, we found that subjects with WCH or masked hypertension had higher BPV than NT. However, long-term follow-up data assessing the clinical influences of WCH on stroke are needed.

Time Rate of Blood Pressure Variation Is Associated With Endothelial Function in Patients With Metabolic Syndrome

The time rate of blood pressure (BP) variation indicates the speed of BP fluctuations. Previous studies have demonstrated that the time rate of BP variation was associated with target organ damage. However, the association between time rate of BP variation and endothelial function has not been evaluated.24-hour ambulatory blood pressure monitoring (ABPM) was performed in 61 patients with metabolic syndrome. Time rate of BP variation was calculated from BP recordings of ABPM. Endothelial function was assessed using reactive hyperemia-peripheral arterial tonometry index (RHI) by EndoPat2000. Multiple linear regression models were used to detect the association between time rate of BP variation and RHI.Among all the subjects (n = 61), the multiple linear regression models revealed that the daytime rate of systolic blood pressure (SBP) variation was independently associated with RHI (β = -0.334, P = 0.008). A 0.1 mmHg/minute increase in the daytime rate of SBP variation correlated with a decline of 0.20 in RHI. The same effect was also found in the subjects with eGFR ≥ 60 mL/ (minute*1.73 m(2)). A greater association was found in those who were not taking a statin, β-blocker, ACEI/ARB, or diuretic and those without diabetes compared with those with any antihypertensive medication or with diabetes. Other ambulatory blood pressure parameters and central hemodynamics were not found to be associated with RHI.Our findings have shown that the daytime rate of SBP variation was associated with endothelial function in patients with metabolic syndrome, independent of other BP parameters and central hemodynamics.

Augmented Blood Pressure Variability in Hypertension Induced by Angiotensin II in Rats

BACKGROUND

Augmented blood pressure (BP) variability is associated with cardiovascular diseases in some clinical conditions including hypertension. Drugs that effectively reduce BP variability need to be identified, while few animal models are currently available to study BP variability. Here, we report that hypertension induced by continuous infusion of angiotensin II (Ang II) was accompanied by increased BP variability in rats.

METHODS

Ang II was subcutaneously infused at a rate of 240 pmol/kg/min into male Wistar rats undergoing intraperitoneal implantation of a transmitter connected to an abdominal aortic catheter. BP was continuously monitored via a telemetry system before and after the Ang II infusion in a conscious, unrestrained condition. BP variability was evaluated by coefficient of variation (CV) of BP levels measured every 15 minutes. In addition, spontaneously hypertensive and Wistar-Kyoto rats (SHR and WKY) were subjected to the BP monitoring experiment at 15 weeks of age.

RESULTS

Both systolic and diastolic BP levels were significantly elevated following the Ang II infusion. Similarly, CVs of systolic and diastolic BP in the Ang II infusion group were significantly higher than in the vehicle group upon 1 and 2 weeks of the infusion. Meanwhile, CVs of systolic and diastolic BP of SHR were in a range similar to those of WKY despite significantly higher BP than in WKY.

CONCLUSIONS

Hypertension induced by the continuous infusion of Ang II was accompanied by augmented BP variability in rats, an effect assumed to be at least in part, independent of BP elevation.

Blood pressure variability and its association with echocardiographic parameters in hypertensive diabetic patients

BACKGROUND

Blood pressure (BP) variability is associated with target organ damage in hypertension and diabetes. The 24 h ambulatory blood pressure monitoring (24 h-ABPM) has been proposed as an evaluation for BP variability using several indexes [standard deviation (SD) of mean BP, coefficient of variation (CV), BP variation over time (time-rate index)].

METHODS

We evaluated the association between BP variability measured by 24 h-ABPM indexes and echocardiographic variables in a cross-sectional study in 305 diabetic-hypertensive patients.

RESULTS

Two groups were defined by the median (0.55 mmHg/min) of time-rate systolic BP (SBP) index and classified as low or high variability. Age was 57.3 ± 6.2 years, 196 (64.3%) were female. Diabetes duration was 10.0 (5.0-16.2) years, HbA1c was 8.2 ± 1.9%. Baseline clinical characteristics were similar between low (n = 148) and high (n = 157) variability groups. Office SBP and systolic 24 h-ABPM were higher in the high variability group (139.9 mmHg vs 146.0 mmHg, P = 0.006; 128.3 mmHg vs 132.9 mmHg, P = 0.019, respectively). Time-rate index, SD and CV of SBP, were higher in high variability group (P < 0.001; P < 0.001 and P = 0.003, respectively). Time-rate index was not independently associated with the echocardiography's variables in multiple linear model when adjusting for age, 24 h-ABPM, diabetes duration and HbA1c. The multiple linear regression model revealed that the significant and independent determinants for septum thickness, relative wall thickness and posterior wall thickness (parameters of left ventricular hypertrophy) were: age (p = 0.025; p = 0.010; p = 0.032, respectively) and 24 h-SBP (p < 0.001 in the three parameters).

CONCLUSION

BP variability estimated by 24 h-ABPM is not independently associated with echocardiographic parameters in diabetic-hypertensive patients.

Blood pressure variability in controlled and uncontrolled blood pressure and its association with left ventricular hypertrophy and diastolic function

High systolic blood pressure (SBP) variability has been associated with higher risk for target-organ damage. In a cross-sectional study done in a tertiary outpatient hypertension clinic, we compared short-term SBP variability among controlled and uncontrolled hypertensive patients and evaluated the association between higher levels of SBP variability and diastolic function and left ventricular hypertrophy (LVH). Patients were evaluated by 24-h ambulatory blood pressure monitoring and transthoracic Doppler echocardiogram. Blood pressure (BP) variability was evaluated by the time-rate index and high variability corresponded to index values in the top quartile of distribution. Echocardiographic parameters were compared in patients with and without higher BP variability within controlled and uncontrolled office BP (⩽140/90 mm Hg). The analyses included 447 patients with 58±12 years of age, 67% were women, 68% white, 43% current or previous smokers and 32% with diabetes mellitus. Among the whole sample, 137 patients had controlled and 310 uncontrolled BP. The 75th percentile cutoff points for the time-rate index were 0.502 mm Hg min(-1) and 0.576 mm Hg min(-1) for participants with controlled and uncontrolled BP, respectively. After adjustment for confounders, the time-rate index did not differ between controlled and uncontrolled patients. BP variability was not associated with LVH or diastolic function in controlled and uncontrolled BP after adjustment for 24-h SBP and age. Patients with controlled and uncontrolled BP had similar SBP variability assessed by time-rate index, which was not associated with LVH or diastolic function. These findings should be confirmed in studies with larger sample size.

Short-term blood pressure variability over 24 h and target organ damage in middle-aged men and women

Blood pressure variability (BPV) has been associated with cardiovascular events; however, the prognostic significance of short-term BPV remains uncertain. As uncertainty also remains as to which measure of variability most accurately describes short-term BPV, this study explores different indices and investigates their relationship with subclinical target organ damage (TOD). We used data from the Mitchelstown Study, a cross-sectional study of Irish adults aged 47-73 years (n=2047). A subsample (1207) underwent 24-h ambulatory BP monitoring (ABPM). As measures of short-term BPV, we estimated the s.d., weighted s.d. (wSD), coefficient of variation (CV) and average real variability (ARV). TOD was documented by microalbuminuria and electrocardiogram (ECG) left ventricular hypertrophy (LVH). There was no association found between any measure of BPV and LVH in both unadjusted and fully adjusted logistic regression models. Similar analysis found that ARV (24 h, day and night), s.d. (day and night) and wSD were all univariately associated with microalbuminuria and remained associated after adjustment for age, gender, smoking, body mass index (BMI), diabetes and antihypertensive treatment. However, when the models were further adjusted for the mean BP the association did not persist for all indices. Our findings illustrate choosing the appropriate summary measure, which accurately captures that short-term BPV is difficult. Despite discrepancies in values between the different measures, there was no association between any indexes of variability with TOD measures after adjustment for the mean BP.

Correlation between the morning hypertension on ambulatory blood pressure monitoring and the left ventricular mass in children

PURPOSE

Although high morning blood pressure (BP) is known to be associated with the onset of cardiovascular events in adults, data on its effects in children with hypertension are limited. Our retrospective study aimed to define the clinical characteristics of children with morning hypertension (MH) and to determine its associated factors.

METHODS

We reviewed 31 consecutive patients with hypertension, confirmed by the ambulatory blood pressure monitoring (ABPM). We divided these patients into 2 groups: the MH group (n=21, 67.7%), morning BP above the 95th percentile for age and height (2 hours on average after waking up) and the normal morning BP group (n=10, 32.3%). We compared the clinical manifestations, laboratory results, and echocardiographic findings including left ventricular hypertrophy (LVH) between the groups.

RESULTS

The early/atrial (E/A) mitral flow velocity ratio in the MH group was significantly lower than that in the normal morning BP group. In addition, LV mass was higher in the MH group than in the normal morning BP group, although the difference was not statistically significant. The age at the time of hypertension diagnosis was significantly higher in the MH group than in the normal morning BP group (P=0.003). The incidence of hyperuricemia was significantly higher in the MH group than in the normal morning BP group.

CONCLUSION

Older patients and those with hyperuricemia are at higher risk for MH. The rise in BP in the morning is an important factor influencing the development of abnormal relaxation, as assessed by echocardiography. Clinical trials with longer follow-up periods and larger sample sizes are needed to clarify the clinical significance of MH.

Effects of vitamin E, vitamin C and polyphenols on the rate of blood pressure variation: results of two randomised controlled trials

High blood pressure (BP) variability, which may be an important determinant of hypertensive end-organ damage, is emerging as an important predictor of cardiovascular health. Dietary antioxidants can influence BP, but their effects on variability are yet to be investigated. The aim of the present study was to assess the effects of vitamin E, vitamin C and polyphenols on the rate of daytime and night-time ambulatory BP variation. To assess these effects, two randomised, double-blind, placebo-controlled trials were performed. In the first trial (vitamin E), fifty-eight individuals with type 2 diabetes were given 500 mg/d of RRR-α-tocopherol, 500 mg/d of mixed tocopherols or placebo for 6 weeks. In the second trial (vitamin C-polyphenols), sixty-nine treated hypertensive individuals were given 500 mg/d of vitamin C, 1000 mg/d of grape-seed polyphenols, both vitamin C and polyphenols, or neither (placebo) for 6 weeks. At baseline and at the end of the 6-week intervention, 24 h ambulatory BP and rate of measurement-to-measurement BP variation were assessed. Compared with placebo, treatment with α-tocopherol, mixed tocopherols, vitamin C and polyphenols did not significantly alter the rate of daytime or night-time systolic BP, diastolic BP or pulse pressure variation (P>0·05). Treatment with the vitamin C and polyphenol combination resulted in higher BP variation: the rate of night-time systolic BP variation (P= 0·022) and pulse pressure variation (P= 0·0036) were higher and the rate of daytime systolic BP variation was higher (P= 0·056). Vitamin E, vitamin C or grape-seed polyphenols did not significantly alter the rate of BP variation. However, the increase in the rate of BP variation suggests that the combination of high doses of vitamin C and polyphenols could be detrimental to treated hypertensive individuals.

Blood pressure variability predicts cognitive decline in Alzheimer's disease patients

The aim of our study was to evaluate whether blood pressure variability influences the rate of cognitive decline in Alzheimer's disease (AD). Two hundred and forty AD patients were periodically evaluated for a 12-month period. The blood pressure (BP) status of each patient was defined through mean and coefficient of variation for both systolic and diastolic BP. Progression of cognitive decline was investigated using the Mini Mental State Examination administered at entry and at the end of follow-up. Among the considered BP indices, only systolic BP variability explained the decrease in the Mini Mental State Examination score after adjustment for confounding variables (multiple linear regression: R(2) = 0.603, adjusted R(2) = 0.513; p < 0.001; logistic regression model: odds ratio = 2.882, 95% confidence interval = 1.772-4.495; p < 0.001). The receiver operating characteristic analysis for evaluating the ability of systolic BP variability to predict a faster cognitive decline presented an area under the curve of 0.913 (95% confidence interval = 0.874-0.953; p < 0.001). Our results suggest that BP variability may be added to the list of the potential vascular risk factors and included in the evaluation of AD patients to better define their risk profile.

Clinical utility of ambulatory blood pressure monitoring in the management of hypertension

Accurate blood pressure (BP) measurement is essential for the diagnosis, monitoring and management of hypertension. However, conventional office-based BP readings have several limitations that include a low reproducibility, the white-coat effect and the existence of masked hypertension. These limitations can be addressed through the use of ambulatory BP monitoring. Because ambulatory monitoring provides measurements at specific time intervals throughout a 24-hour period, this technique represents a better picture of the normal fluctuations in BP levels associated with daily activities and sleep. In addition, end-organ damage associated with hypertension is more closely related to ambulatory BP than office BP measurements and ambulatory BP profile give better prediction of clinical outcome than conventional BP measurements.

Nighttime blood pressure, systolic blood pressure variability, and left ventricular mass index in children with hypertension

BACKGROUND

Nighttime blood pressure (BP) and systolic BP variability on ambulatory blood pressure monitoring (ABPM) have been strongly associated with target-organ damage in hypertensive adults. The clinical relevance of these variables in children with hypertension remains under-studied.

METHODS

The study group included children aged 5-18 years old referred to the outpatient nephrology clinic for an elevated casual BP who underwent an ABPM and echocardiography (ECHO) study and did not have secondary hypertension. The interpretation of ABPM parameters and left ventricular mass index (LVMI) was based on normative references.

RESULTS

Seventy-two children fulfilled the inclusion criteria. The association of various potential predictors including age, BMI z-score, casual BP z-score and ABPM parameters (BP z-score, BP load, nocturnal dipping and BP variability- within-subject standard deviation (SD) of BP) with LVMI was analyzed. On adjusted regression analysis, nighttime systolic BP load [standardized regression coefficient (β) 0.23; p < 0.05] and daytime systolic BP variability (β 0.37; p < 0.05) had significant association with LVMI.

CONCLUSIONS

In children with primary hypertension, nighttime systolic BP load and daytime systolic BP variability had a stronger association with LVMI than casual BP and other ABPM parameters. Future longitudinal studies are needed to establish the causality among these variables.

Black tea lowers the rate of blood pressure variation: a randomized controlled trial

BACKGROUND

Measures of blood pressure variation have been associated with cardiovascular disease and related outcomes. The regular consumption of black tea can lower blood pressure, but its effects on blood pressure variation have yet to be investigated.

OBJECTIVE

We aimed to assess the effects of black tea consumption on the rate of ambulatory blood pressure variation.

DESIGN

Men and women (n = 111) with systolic blood pressure between 115 and 150 mm Hg at screening were recruited in a randomized, controlled, double-blind, 6-mo parallel-designed trial designed primarily to assess effects on blood pressure. Participants consumed 3 cups/d of either powdered black tea solids (tea) or a flavonoid-free caffeine-matched beverage (control). The 24-h ambulatory blood pressure level and rate of measurement-to-measurement blood pressure variation were assessed at baseline, day 1, and 3 and 6 mo.

RESULTS

Across the 3 time points, tea, compared with the control, resulted in lower rates of systolic (P = 0.0045) and diastolic (P = 0.016) blood pressure variation by ~10% during nighttime (2200-0600). These effects, which were immediate at day 1 and sustained over 6 mo, were independent of the level of blood pressure and heart rate. The rate of blood pressure variation was not significantly altered during daytime (0800-2000).

CONCLUSIONS

These findings indicate that a component of black tea solids, other than caffeine, can influence the rate of blood pressure variation during nighttime. Thus, small dietary changes have the potential to significantly influence the rate of blood pressure variation. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTR12607000543482.

Time rate of blood pressure variation: a new factor associated with coronary atherosclerosis

OBJECTIVES

Previous studies have demonstrated that the time rate of blood pressure (BP) variation was associated with early carotid atherosclerosis, independent of peripheral and central BP levels. We evaluated the association between the rate of BP variation, derived from ambulatory BP monitoring (ABPM) data analysis, and the severity and topography of coronary artery lesion in a cohort of normotensive patients with suspected coronary artery disease.

METHODS

ABPM and coronary angiography were performed in 162 normotensive patients with suspected coronary artery disease. The topography and severity of coronary artery lesions were assessed by Gensini score. The time rate of BP variation was defined as the first derivative of the BP values against time.

RESULTS

Patients with coronary artery disease (n = 123) presented significantly (P = 0.005) higher daytime rate of systolic BP variation than control patients (n = 39). Multiple linear regression models revealed independent determinants of Gensini score in the following rank order: diabetes mellitus (β: +0.286, P < 0.001), daytime rate of systolic BP variation (β: +0.277, P < 0.001), daytime systolic BP (β: +0.216, P = 0.002), smoking (β: +0.178, P = 0.008) and hypercholesterolemia (β: +0.158, P = 0.020). A 0.1 mmHg/min increase in the daytime rate of systolic BP variation correlated with an increment of 4.935 in the Gensini score (95% CI 2.432-7.438).

CONCLUSION

Steeper BP variations may produce a greater stress on the arterial wall and may have an additive role to vascular risk factors and BP parameters in the detection of the severity of coronary artery lesions in normotensive individuals with suspected coronary artery disease.

Is left ventricular dysfunction reversed after treatment of active acromegaly?

It has been suggested that control of GH and IGF excess can arrest the progression of cardiovascular abnormalities and normalize cardiac performance. The aim of the present study was to investigate the reversibility of acromegalic cardiomyopathy in patients with active and inactive disease and to evaluate the effect of the inactivity of the disease on left ventricular (LV) diastolic dysfunction, irrespective of the applied treatment. The patient population consisted of 55 patients who were studied in the active and/or inactive phase. A complete M-mode, two-dimensional and color-flow Doppler echocardiographic examination was performed. LV mass index and posterior wall index were significantly lower in patients with inactive acromegaly compared to those with active disease (P < 0.03 respectively). Diastolic dysfunction was improved in patients with inactive compared to those with active disease (E/A ratio P < 0.009). IGF was positively correlated with LV mass index (r = 0.28, P < 0.02). Multivariate linear regression analysis showed that in active patients the E/A ratio was independently related to age (β = -0.674, P < 0.001) and GH (β = 0.282, P < 0.03), whereas in inactive patients none of the parameters were related significantly with the E/A ratio. In a subgroup of 15 patients who were studied in both the active and inactive phase of the disease, the reduction in GH levels was correlated positively with the reduction in LV mass index (r = 0.89, P < 0.0001) and negatively with the improvement in E/A ratio (r = -0.74, P < 0.001). In conclusion, the results of the present study indicate an improvement of left ventricular diastolic function and a significant improvement of cardiac hypertrophy in patients with inactive acromegaly and normal systolic cardiac function compared to those with active disease.

Time rate of blood pressure variation is associated with impaired renal function in hypertensive patients

OBJECTIVES

The rate of blood pressure (BP) variation has been positively associated with intima-media thickness of common carotid arteries and left ventricular mass. We evaluated the association between the rate of BP variation derived from ambulatory blood pressure monitoring (ABPM) data analysis and impaired renal function.

METHODS

Twenty-four-hour ABPM was performed in 803 untreated hypertensive patients. The estimated glomerular filtration rate (eGFR) was assessed using the abbreviated equation of the Modification Diet for Renal Disease study. Patients were divided into two groups: those with an eGFR less than 60 ml/min per 1.73 m(2) (group A) and those with an eGFR 60 ml/min per 1.73 m(2) or more (group B).

RESULTS

The 24-h rate of systolic BP variation was significantly (P = 0.004) higher in group A [0.616 mmHg/min; 95% confidence interval (CI) 0.596-0.636] than in group B patients (0.585 mmHg/min; 95% CI 0.578-0.591), even after adjusting for baseline characteristics and ABPM parameters. In the entire study population, the multiple logistic regression models revealed the following variables as independent determinants of impaired renal function: age, male sex, office systolic BP and 24-h rate of systolic BP variation. In this model, the odds ratio for impaired renal function associated with each 0.1 mmHg/min increase in 24-h rate of systolic BP variation was 1.49 (95% CI 1.18-1.88, P = 0.001).

CONCLUSION

The 24-h rate of SBP variation is independently associated with impaired renal function. Target-organ damage in hypertensive patients, in addition to BP levels, dipping status and BP variability, may also be related to a steeper rate of BP fluctuations.

Periodic limb movement during sleep is associated with nocturnal hypertension in children

BACKGROUND

Increasing evidence suggests that blood pressure (BP) is significantly influenced by sleep problems in children, but the association between periodic limb movement during sleep (PLMS) and BP is still unclear. This study aims to compare ambulatory blood pressure (ABP) in children with and without PLMS.

METHODS AND RESULTS

A cross-sectional study involving 314 children (mean (SD) age of 10.4 (1.7) years, boys 62.4%). Participants underwent an overnight polysomnographic study and ABP monitoring. Subjects were hypertensive if mean SBP or DBP > 95th percentile and prehypertensive if mean SBP or DBP > 90th percentile of reference. Children with PLMS (n = 17) were at significantly higher risk for nocturnal systolic (adjusted OR (95%CI) = 6.25 [1.87-20.88]) and diastolic (OR (95%CI) = 4.83 [1.66-14.07]) hypertension. However, mean nocturnal BP did not differ between children with and without PLMS. There was a trend for higher daytime BP in patients with PLMS than those children without PLMS (P = 0.084 for systolic BP z score; P = 0.051 for diastolic BP z score; P = 0.067 for systolic prehypertension). There were significant associations between log transformed PLM index and daytime systolic and mean BP z scores (P = 0.03 and 0.033 respectively) as well as that between log transformed PLM related arousal index (PLMSArI) and nocturnal diastolic and mean BP (P = 0.008 and 0.038 respectively).

CONCLUSIONS

PLMS was independently associated with a wide range of BP elevations, especially nocturnal indices. Future studies should examine the underlying pathophysiologic mechanisms and effects of PLMS treatment on BP.

Impact of Prehypertension on Common Carotid Artery Intima-Media Thickness and Left Ventricular Mass

Background and Purpose— Prehypertension has been recently introduced by JNC 7 as a new blood pressure (BP) category, associated with increased target-organ damage. Subclinical atherosclerosis by means of common artery intima-media thickness (CCA-IMT) has been incompletely investigated in prehypertensive patients. The aim of our study was to assess the extent of CCA-IMT and left ventricular mass (LVM) in prehypertensive adults in comparison to normotensive and untreated hypertensive subjects.

Methods— From a total of 5221 consecutive patients screened to our Hypertension Unit we selected 896 consecutive individuals according to prespecified inclusion criteria, who underwent 24-hour ambulatory BP monitoring, carotid artery ultrasonographic, and echocardiographic measurements. Patients who received antihypertensive treatment during the BP monitoring were excluded. According to the office BP levels, patients were divided into 3 subgroups: normotensives (office BP <120/80 mm Hg), prehypertensives (120/80 mm Hg≤office BP<140/90 mm Hg), and hypertensives (office BP ≥140/90 mm Hg). Statistical analyses were performed by means of 1-way ANOVA, χ 2 test, and ANCOVA.

Results— According to the office BP levels, the distribution of the study population was: normotensives (14.4%), prehypertensives (23.7%), and hypertensives (61.9%). Prehypertensive patients had higher CCA-IMT ( P =0.038) and LVM ( P =0.030) values than normotensive subjects, even after adjustment for baseline characteristics. Greater CCA-IMT values were observed in hypertensive patients in comparison to prehypertensives ( P =0.002).

Conclusions— Prehypertensive patients had higher CCA-IMT and LVM than their normotensive counterparts. Prehypertension status is cross-sectionally associated with subclinical atherosclerosis and target-organ damage.

Left ventricular mass index in children with white coat hypertension

OBJECTIVES

To determine whether children with white coat hypertension (WCH) have evidence of target-organ damage by comparing the left ventricular mass index (LVMI) of subjects with WCH with that of matched normotensive and hypertensive controls.

STUDY DESIGN

Each subject in the WCH group was matched by body mass index (BMI; +/- 10%), age (+/- 1 year), and sex to a normotensive control and a hypertensive control. Echocardiograms were reviewed to determine the LVMI for each subject. These triple matches were analyzed using repeated-measures analysis of variance to detect differences in LVMI among the 3 groups.

RESULTS

A total of 27 matched triplets were established. The groups were comparable for sex, age, and BMI. Mean LVMI was 29.2 g/m(2.7) for the normotensive group, 32.3 g/m(2.7) for the WCH group, and 35.1 g/m(2.7) for the sustained hypertensive group (normotensive vs WCH, P = .028; WCH vs sustained hypertension, P = .07). Left ventricular hypertrophy was not present in any subject in the normotensive or WCH groups, but was found in 26% of the sustained hypertensive subjects (P < .001).

CONCLUSIONS

After controlling closely for BMI, the LVMI in the subjects with WCH was between that of the normotensives and sustained hypertensives, suggesting that WCH may be associated with hypertensive end-organ effects.

Left ventricular hypertrophy and clinical outcomes in hypertensive patients

The prevalence of left ventricular hypertrophy (LVH) rises with severity of hypertension (HT), age, and obesity. Its prevalence ranges from 20% in mildly hypertensive patients to almost 100% in those with severe or complicated HT. However, the diagnosis of LVH is not straightforward, and the definitions and criteria used in clinical studies lack consistency. While many factors play a role in the onset and progression of LVH, blood pressure (BP) is recognized as a central factor. Twenty-four-hour BP measurements are more closely related to LVH than conventional BP readings taken in the clinician's office. Increased renin-angiotensin system (RAS) activity also plays an important role in the development of LVH, and various studies show a correlation between plasma renin activity and left ventricular mass (LVM). LVH is a recognized marker of HT-related target organ damage, and a strong and independent risk factor for adverse cardiovascular (CV) outcomes. CV risk increases with increasing LVM, and decreases with regression of LVH in response to antihypertensive treatment. Therefore the detection, prevention, and reversal of LVH are important goals in HT management. Most antihypertensive drugs can attenuate BP and LVH. However, each drug class may induce LVH regression to a different extent and these extents seldom correlate with the degree of BP reduction achieved. Data from the few large comparative studies in this area suggest that certain classes of antihypertensive drugs and/or their combinations are more effective than others. In particular, calcium channel blockers and drugs that target the RAS, such as angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), appear to have a specific effect on LVH, independent of BP reduction. Guidelines, therefore, have recommended these drug classes for the treatment of hypertensive patients with LVH.