The use of ambulatory tonometric radial arterial wave capture to measure ambulatory blood pressure: the validation of a novel wrist-bound device in adults

Blood pressure circadian pattern and physical exercise assessment by accelerometer and 7-day physical activity recall scale

BACKGROUND

The relationship between regular physical activity, measured objectively and by self-report, and the circadian pattern of 24-hour ambulatory arterial blood pressure (BP) has not been clarified.

METHODS

We performed a cross-sectional study in a cohort of healthy patients. We included 1,345 patients from the EVIDENT study (mean age 55 ± 14 years; 59.3% women). Physical activity was assessed using the 7-day physical activity recall (PAR) questionnaire (metabolic equivalents (MET)/hour/week) and the Actigraph GT3X accelerometer (counts/minute) for 7 days; ambulatory arterial BP was measured with a radial tonometer (B-pro device).

RESULTS

The dipper-pattern patients showed a higher level of activity than nondipper patients, as assessed by accelerometer and 7-day PAR. Physical activity measures correlated positively with the percent drop in systolic BP (SBP; ρ = 0.19 to 0.11; P < 0.01) and negatively with the systolic and diastolic sleep to wake ratios (ρ = -0.10 to -0.18; P < 0.01) and heart rate (ρ = -0.13; P < 0.01). In logistic regression, considering the circadian pattern (1, dipper; 0, nondipper) as the dependent variable, the odds ratio of the third tertile of counts/minute was 1.79 (95% confidence interval [CI], 1.35-2.38; P < 0.01) and of MET/hour/week was 1.33 (95% CI, 1.01-1.75; P = 0.04) after adjustment for confounding variables.

CONCLUSIONS

Physical activity, as evaluated by both the accelerometer and the 7-day PAR, was associated with a more marked nocturnal BP dip and, accordingly, a lower SBP and diastolic BP sleep to wake ratio.

CLINICAL TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT01083082.

Vascular calcification is not associated with increased ambulatory central aortic systolic pressure in prevalent dialysis patients

Introduction

Central aortic systolic pressure (CASP) strongly predicts cardiovascular outcomes. We undertook to measure ambulatory CASP in 74 prevalent dialysis patients using the BPro (HealthStats, Singapore) device. We also determined whether coronary or abdominal aortic calcification was associated with changes in CASP and whether interdialytic CASP predicted ambulatory measurement.

Methods

All patients underwent computed tomography for coronary calcium score, lateral abdominal radiography for aortic calcium score, echocardiography for left ventricular mass index and ambulatory blood pressure measurement using BPro calibrated to brachial blood pressure. HealthStats was able to convert standard BPro SOFT® data into ambulatory CASP.

Results

Ambulatory CASP was not different in those without and with coronary (137.6 vs 141.8 mmHg, respectively, p = 0.6) or aortic (136.6 vs 145.6 mmHg, respectively, p = 0.2) calcification. Furthermore, when expressed as a percentage of brachial systolic blood pressure to control for peripheral blood pressure, any difference in CASP was abolished: CASP: brachial systolic blood pressure ratio = 0.9 across all categories regardless of the presence of coronary or aortic calcification (p = 0.2 and 0.4, respectively). Supporting this finding, left ventricular mass index was also not different in those with or without vascular calcification (p = 0.7 and 0.8 for coronary and aortic calcification). Inter-dialytic office blood pressure and CASP correlated excellently with ambulatory measurements (r = 0.9 for both).

Conclusion

Vascular calcification was not associated with changes in ambulatory central aortic systolic pressure in this cohort of prevalent dialysis patients. Inter-dialytic blood pressure and CASP correlated very well with ambulatory measurement.

Electrocardiographic left ventricular hypertrophy criteria and ambulatory blood pressure monitoring parameters in adults

BACKGROUND

To examine the relationship between ambulatory blood pressure monitoring parameters (ABPM) and electrocardiographic criteria for left-ventricular hypertrophy (LVH) in adults.

METHODS

This study analyzed 1,544 subjects from the EVIDENT study (mean age = 55 ± 14 years; 61% women). A standard electrocardiograph (ECG) and 10 criteria were used to detect LVH. Office and ABPM were performed, and we analyzed 24-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP), percentage of time awake with SBP ≥135 mm Hg, percentage of time asleep with SBP ≥120 mm Hg, and central aortic blood pressure.

RESULTS

LVH according to some electrocardiographic criteria was found in 11.30% of the patients (16.60% of men and 7.70% of women). The patients with LVH were older; had higher values for office, 24-hour and, central aortic blood pressure; were more likely to be men; and had a higher prevalence of obesity, diabetes, and antihypertensive or lipid-lowering drug use. In the logistic regression analysis, the association between the parameters of ABPM and LVH, after adjusting for age, sex, body mass index, and heart rate, remained statistically significant.

CONCLUSIONS

Twenty-four hour blood pressure, the percentage of time with elevated awake and asleep SBPs, and the central systolic blood pressure are related to the presence of LVH as determined by ECG in adults. These results indicate the potential importance of the monitoring and control of different 24-hour parameters of blood pressure in addition to the standard clinic blood pressure with respect to the development of LVH.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01325064.

Relationship between objectively measured physical activity and cardiovascular aging in the general population--the EVIDENT trial

BACKGROUND

Aging has been associated with an increase in arterial stiffness. We analyzed the relationship between regular physical activity and cardiovascular aging evaluated by the radial augmentation index (rAIx), ambulatory arterial stiffness index (AASI), pulse pressure (PP) and heart age in subjects without atherosclerotic disease.

METHODS

A cross-sectional study was performed including 1365 subjects from the EVIDENT trial (mean age 54.9±13.7 years; 60.3% women). As a measure of total volume of physical activity we used counts/minute recorded in an accelerometer (Actigraph GT3X) that participants wore for seven days, collecting data in 60-sec epochs, and respondents with ≥4 valid days were retained for the analysis. Arterial stiffness was evaluated using measures of rAIx, AASI, and central and peripheral PP on the B-pro device. rAIx was adjusted to 75 heart rate(rAIx75). Cardiovascular risk and heart age was estimated by the Framingham Risk Score.

RESULTS

The median (IQR) of counts/min was 236.9 (176.3-307.8), rAIx75 90 (77-100), sleep PP 40 mmHg (33-47), central PP 39 mmHg (32-47) and heart age 57 years (45-73) and the mean±SD of the ASSI was 0.44±0.07. We found an inverse correlation between counts/minute and rAIx75 (r=-0.086; p<0.01), AASI (r=-0.146; p<0.001), heart age (r=-0.163; p<0.001) and peripherals PP. These associations were remained after controlling for potential confounders, except for rAIx75. In the multiple regression analysis, after adjustment, an inverse association persisted between counts/minute and AASI, sleep PP and heart age, but not with rAIx75. Accordingly, for every 100 higher counts/minute of accelerometer measures, both AASI and sleep PP would be lower by one measurement unit (beta=-0.979 and -1.031 respectively, p<0.001) and the estimated heart age by half year (beta=-0.525, p=0.023).

CONCLUSIONS

Regular physical activity was inversely associated with parameters related to advanced cardiovascular aging after adjustment for potentially influencing variables.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT01083082.

24-hour central aortic systolic pressure and 24-hour central pulse pressure are related to diabetic complications in type 1 diabetes - a cross-sectional study

BACKGROUND

Non-invasive measurements of 24 hour ambulatory central aortic systolic pressure (24 h-CASP) and central pulse pressure (24 h-CPP) are now feasible. We evaluate the relationship between 24 h central blood pressure and diabetes-related complications in patients with type 1 diabetes.

METHODS

The study was cross-sectional, including 715 subjects: 86 controls (C), 69 patients with short diabetes duration (< 10 years), normoalbuminuria (< 30 mg/24 h) without receiving antihypertensive treatment (SN), 211 with longstanding diabetes (≥ 10 years) and normoalbuminuria (LN), 163 with microalbuminuria (30-299 mg/24 h) (Mi) and 186 with macroalbuminuria (> 300 mg/24 h) (Ma).24 h-CASP and 24 h-CPP was measured using a tonometric wrist-watch-like device (BPro, HealthStats, Singapore) and derived using N-point moving average.

RESULTS

In C, SN, LN, Mi and Ma mean ± SD 24 h-CASP was: 114 ± 17, 115 ± 13, 121 ± 13, 119 ± 16 and 121 ± 13 mmHg (p < 0.001); and 24 h-CPP: 38 ± 8, 38 ± 7, 44 ± 10, 46 ± 11 and 46 ± 11 mmHg, (p < 0.001).Following rigorous adjustment (24 h mean arterial pressure and conventional risk factors), 24 h-CASP and 24 h-CPP increased with diabetes, albuminuria degree, previous cardiovascular disease (CVD), retinopathy and autonomic dysfunction (p ≤ 0.031).Odds ratios per 1 standard deviation increase in 24 h-CASP, 24 h-CPP and 24 h systolic blood pressure (24 h-SBP) were for CVD: 3.19 (1.68-6.05), 1.43 (1.01-2.02) and 2.39 (1.32-4.33), retinopathy: 4.41 (2.03-9.57), 1.77 (1.17-2.68) and 3.72 (1.85-7.47) and autonomic dysfunction: 3.25 (1.65-6.41), 1.64 (1.12-2.39) and 2.89 (1.54-5.42).

CONCLUSIONS

24 h-CASP and 24 h-CPP was higher in patients vs. controls and increased with diabetic complications independently of covariates. Furthermore, 24 h-CASP was stronger associated to complications than 24 h-SBP.The prognostic significance of 24 h-CASP and 24 h-CPP needs to be determined in follow-up studies.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT01171248.

Novel description of the 24-hour circadian rhythms of brachial versus central aortic blood pressure and the impact of blood pressure treatment in a randomized controlled clinical trial: The Ambulatory Central Aortic Pressure (AmCAP) Study

Elevated brachial blood pressure (BP) is associated with increased cardiovascular risk and predicts morbidity and mortality in humans. Recently, 24-hour ambulatory BP monitoring and assessment of central aortic BP have been introduced to improve BP phenotyping. The Ambulatory Central Aortic Pressure (AmCAP) study combines these approaches and describes, for the first time, the diurnal patterns of simultaneously measured 24-hour ambulatory brachial and central pressures in a prespecified substudy embedded within a clinical trial of BP lowering in patients with hypertension. Twenty-four-hour ambulatory brachial and central pressure measurements were acquired using a tonometer mounted into the articulating strap of a wristwatch-like device (BPro) in 171 participants with hypertension recruited into the ASSERTIVE (AliSkiren Study of profound antihypERtensive efficacy in hyperTensIVE patients) trial. Participants were randomly assigned to BP lowering with either aliskiren 300 mg QD or telmisartan 80 mg QD for 12 weeks. Ambulatory brachial and central BP was measured in all participants both at baseline and at study end. Brachial and central BP both demonstrated typical diurnal patterns with lower pressures at night. However, night time was associated with smaller reductions in central relative to brachial pressure and decreased pulse pressure amplification (P<0.0001 for both). These effects were not modulated after BP lowering and were maintained after adjustment for day and night-time BP and heart rate (P=0.02). This study demonstrates that brachial and central pressure show different diurnal patterns, which are not modulated by BP-lowering therapy, with relatively higher night-time central pressures. These novel data indicate that night-time central BP may provide prognostic importance and warrants further investigation. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00865020.

Association of television viewing time with central hemodynamic parameters and the radial augmentation index in adults

BACKGROUND

We conducted a study to explore the relationship between television viewing time and central hemodynamic parameters and the radial augmentation index (AIx) in adults.

METHODS

Random sampling was used to select 732 individuals who attended primary-care centers as subjects for the study. The self-reported time that these individuals spent in viewing television was elicited with a questionnaire and included the number of hours that they spent watching television while sitting or lying down. The subjects' physical activity was estimated through accelerometers attached to their waists. Central hemodynamic parameters and the peripheral augmentation index adjusted for a heart rate of 75 bpm (PAIx75) were measured with pulse-wave application software (A-Pulse CASP).

RESULTS

The subjects' systolic blood pressure (SBP) (central and peripheral), pulse pressure, and radial AIx showed significant differences between tertiles of television viewing time, with the lowest values in the first tertile (P < 0.01). After adjustment for age and sex, a multiple linear regression analysis showed an association of television viewing time with office SBP. Although the association of television viewing time with central SBP followed the same trend as for office BP, it did not reach statistical significance. After adjustment for age, sex, waist-to-height ratio, physical activity reflected by accelerometer data (counts/min), high-density lipoprotein cholesterol, smoking, antihypertensive and antidiabetic medication, and the use of lipid-lowering drugs, an increase in PAIx75 of 0.22 was estimated for each hour of increase in television viewing time (P < 0.01).

CONCLUSIONS

Television viewing time was directly correlated with PAIx75 in an adult population. This correlation was maintained even after adjustment for physical activity, age, sex, and other cardiovascular risk factors.

Arterial stiffness is associated with cardiovascular, renal, retinal, and autonomic disease in type 1 diabetes

OBJECTIVE

In patients with type 1 diabetes, we investigated the association between arterial stiffness and diabetes complications.

RESEARCH DESIGN AND METHODS

This was a cross-sectional study including 676 Caucasian patients with type 1 diabetes (374 [55%] men, aged 54 ± 13 years [mean ± SD]) and 51 nondiabetic controls (28 [55%] men, aged 47 ± 13 years). Aortic pulse wave velocity (PWV) was measured with SphygmoCor (AtCor Medical, Sydney, Australia) for 635 patients and all 51 controls.

RESULTS

PWVs (mean ± SD) in patients and controls were 10.4 ± 3.4 and 7.6 ± 1.9 m/s, respectively (P < 0.001). After multivariate adjustment, PWV correlated with age, diabetes duration, urinary albumin excretion rate, heart rate, and blood pressure (P < 0.05 for all). ANCOVA was used for comparisons between groups and adjusted for gender, age, estimated glomerular filtration rate, heart rate, HbA(1c), and 24-h mean arterial pressure. PWVs in normoalbuminuric, microalbuminuric, and macroalbuminuric patients were 9.5 ± 3.2, 11.0 ± 3.6, and 11.4 ± 3.0 m/s, respectively (adjusted P < 0.001). PWV in patients with previous cardiovascular disease, versus patients without, was 12.1 ± 3.5 vs. 10.0 ± 3.2 m/s, respectively (adjusted P < 0.001). PWVs in patients with high (≥140/90 mmHg) versus intermediate (130-40/80-89 mmHg) and low (<130/80 mmHg) blood pressure were 11.8 ± 3.6, 10.0 ± 3.0, and 9.8 ± 3.3 m/s, respectively (adjusted P < 0.001). Furthermore, PWV increased with increasing degree of retinopathy: 8.0 ± 2.5 m/s (nil), 10.0 ± 2.8 m/s (simplex), 12.1 ± 3.5 m/s (proliferative), and 12.7 ± 2.4 m/s (blind), respectively (adjusted P < 0.001). Finally, PWV increased with abnormal heart rate variability: 11.5 ± 3.3 m/s vs. 10.1 ± 3.1 m/s (borderline) and 8.1 ± 2.1 m/s (normal) (adjusted P = 0.027).

CONCLUSIONS

Arterial stiffness increased with presence and duration of type 1 diabetes. Furthermore, PWV increased with all the investigated diabetes complications (cardiovascular, renal, retinal, and autonomic disease) independently of other risk factors.

Vascular calcification in South African dialysis patients: ethnic variation, prevalence, detection and haemodynamic correlates

AIM

Studies from the US have shown little effect of ethnicity on vascular calcification in dialysis patients. This has not been examined in the multi-ethnic population of South Africa where genetic and environmental differences may exist. We assessed the extent and severity of vascular calcification in South African dialysis patients according to race and known risk factors. We further evaluated the association of abdominal aorta calcification with coronary artery calcification.

METHOD

Seventy-five CKD-5D patients and 20 healthy controls were enrolled consecutively. All subjects underwent chest computed tomography for coronary calcium score and abdominal X-ray for abdominal aorta calcium score. Ambulatory blood pressure monitoring was generated via radial artery applanation tonometry.

RESULTS

Coronary calcification was present in 38.6% of patients and was associated with age and prior cardiovascular disease on multivariate analyses. The median coronary calcium score in black patients was 0 (IQR 0) and 66 in non-Blacks (IQR 383, P < 0.001); controls had a coronary calcium score of 0 (IQR 0). Black race remained a significant negative predictor for coronary calcification after adjustment, prevalence ratio = 0.14 and 95% confidence interval (CI): 0.0-0.53. Vascular calcification was not associated with any ambulatory blood pressure parameter. Using receiver operator characteristic curves, an abdominal aorta calcification score of ≥1 showed an area under the curve of 0.83 to predict a coronary calcium score ≥ 10.

CONCLUSION

Black race appears to protect from vascular calcification in South African CKD-5D patients and this warrants further study regarding the underlying mechanism. The abdominal X-ray is a useful screening tool for coronary calcification.

Twenty-four-hour profile of central blood pressure and central-to-peripheral systolic pressure amplification

BACKGROUND

The significant difference in central and peripheral blood pressure (BP) values has only recently been widely recognized. Ambulatory BP monitoring has been shown to have advantages over office BP measurements because ambulatory monitoring can provide important information not available when only office BP is measured. The aim of this study was to assess the 24-hour central systolic pressure (CSP) profile, CSP short-term variability, and 24-hour systolic pressure amplification profile.

METHODS

The study group comprised 50 hypertensive subjects and 50 normotensive subjects. All participants underwent 24-hour peripheral and central pressure monitoring.

RESULTS

CSP was lower than peripheral pressure levels during the day (124.1 ± 15.7 mm Hg vs 133.9 ± 16.3 mm Hg; P < 0.001) and night hours (114.4 ± 14.5 mm Hg vs 121.5 ± 15.2 mm Hg; P < 0.001). The CSP nocturnal fall was lower than the peripheral pressure fall in normotensive subjects as well as in hypertensive subjects. Although 24-hour systolic pressure amplification was similar in subjects with and without hypertension (9.2 ± 3.1 mm Hg and 8.3 ± 2.4 mm Hg; P = NS), it was significantly lower during the night than during the day in both groups. The nocturnal fall in systolic pressure amplification was correlated with the day-night difference in heart rate (r = 0.70; P < 0.001).

CONCLUSIONS

Central pressure differs significantly from peripheral pressure during regular daily activity as well as during night hours. Moreover, it appears that systolic pressure amplification varies throughout the 24-hour period and that the main factor determining nocturnal fall in systolic pressure amplification is nocturnal drop in the heart rate. More studies are required to demonstrate advantage of this novel technique over traditional pressure monitoring in clinical practice.

Ambulatory tonometric blood pressure measurements in patients with diabetes

BACKGROUND

Arterial tonometry is a novel technique for measuring ambulatory blood pressure (AMBP). The watch-like device BPro(®) (HealthSTATS International, Singapore) captures radial pulsewave reflection and calculates brachial blood pressure (BP). In this study we investigate if arterial tonometry is applicable and reliable in patients with diabetes.

SUBJECTS AND METHODS

We compared tonometric (BPro) to cuff-based oscillometric and auscultatoric BPs (Takeda model TM2421, A&D Medical, Tokyo, Japan) in 25 Caucasian patients with type 1 or type 2 diabetes. Patients were seen twice within 2 weeks. At visit 1, a 15-min rest was followed by the recording of three cuff-based BPs and 2-min continuous tonometric BPs. At both visits 24-h AMBP measurements were recorded with the BPro device.

RESULTS

At Visit 1, auscultatoric BP (mean±SD) was 136±19/72±8 mm Hg versus 138±19/78±8 mm Hg with the tonometric device. Visit 1 AMBP was 131±20/76±9 mm Hg versus 131±12/75±9 mm Hg at Visit 2. Mean 24-h AMBP, daytime BP, nighttime BP, and dipping at the two visits were similar (P>0.40). Linear and intraclass correlations coefficients between auscultatoric and tonometric systolic and diastolic BP were r=0.86 and 0.65, respectively (P<0.001 for both), and r=0.83 and 0.77, respectively (P<0.001 for both). The mean differences between devices were 1.9±10 and 5.5±6.6 mm Hg for systolic and diastolic BP, respectively.

CONCLUSIONS

In patients with diabetes tonometric and cuff-based BPs are comparable, and tonometric AMBPs are reproducible and feasible.

The "systolic volume balance" method for the noninvasive estimation of cardiac output based on pressure wave analysis

Cardiac output (CO) monitoring is essential for the optimal management of critically ill patients. Several mathematical methods have been proposed for CO estimation based on pressure waveform analysis. Most of them depend on invasive recording of blood pressure and require repeated calibrations, and they suffer from decreased accuracy under specific conditions. A new systolic volume balance (SVB) method, including a simpler empirical form (eSVB), was derived from basic physical principles that govern blood flow and, in particular, a volume balance approach for the conservation of mass ejected into and flowed out of the arterial system during systole. The formulas were validated by a one-dimensional model of the systemic arterial tree. Comparisons of CO estimates between the proposed and previous methods were performed in terms of agreement and accuracy using "real" CO values of the model as a reference. Five hundred and seven different hemodynamic cases were simulated by altering cardiac period, arterial compliance, and resistance. CO could be accurately estimated by the SVB method as follows: CO = C × PP(ao)/(T - P(sm) × T(s)/P(m)) and by the eSVB method as follows: CO = k × C × PP(ao)/T, where C is arterial compliance, PP(ao) is aortic pulse pressure, T is cardiac period, P(sm) is mean systolic pressure, T(s) is systolic duration, P(m) is mean pressure, and k is an empirical coefficient. SVB applied on aortic pressure waves did not require calibration or empirical correction for CO estimation. An empirical coefficient was necessary for brachial pressure wave analysis. The difference of SVB-derived CO from model CO (for brachial waves) was 0.042 ± 0.341 l/min, and the limits of agreement were -0.7 to 0.6 l/min, indicating high accuracy. The intraclass correlation coefficient and root mean square error between estimated and "real" CO were 0.861 and 0.041 l/min, respectively, indicating very good accuracy. eSVB also provided accurate estimation of CO. An in vivo validation study of the proposed methods remains to be conducted.

Electrocardiographic changes with the onset of diabetes and the impact of aerobic exercise training in the Zucker Diabetic Fatty (ZDF) rat

Background

Early markers of diabetic autonomic neuropathy (DAN) in an electrocardiogram (ECG) include elevated R wave amplitudes, widening of QT_c intervals and decreased heart rate variability (HRV). The severity of DAN has a direct relationship with mortality risk. Aerobic exercise training is a common recommendation for the delay and possible reversal of cardiac dysfunction. Limited research exists on ECG measures for the evaluation of aerobic exercise training in Zucker Diabetic Fatty (ZDF) rat, a model of type 2 diabetes. The objective of this study was to assess whether aerobic exercise training may attenuate diabetes induced ECG changes.

Methods

Male ZDF (obese fa/fa) and control Zucker (lean fa/+) rats were assigned to 4 groups: sedentary control (SC), sedentary diabetic (SD), exercised control (EC) and exercised diabetic (ED). The exercised groups began 7 weeks of treadmill training after the development of diabetes in the ED group. Baseline (prior to the training) and termination measurements included body weight, heart weight, blood glucose and glycated hemoglobin levels and ECG parameters. One way repeated measures ANOVA (group) analyzed within and between subject differences and interactions. Pearson coefficients and descriptive statistics described variable relationships and animal characteristics.

Results

Diabetes caused crucial changes in R wave amplitudes (p < 0.001), heart rate variability (p < 0.01), QT intervals (p < 0.001) and QT_c intervals (p < 0.001). R wave amplitude augmentation in SD rats from baseline to termination was ameliorated by exercise, resulting in R wave amplitude changes in ED animals similar to control rats. Aerobic exercise training neither attenuated QT or QT_c interval prolongation nor restored decreases in HRV in diabetic rats.

Conclusion

This study revealed alterations in R wave amplitudes, HRV, QT and QT_c intervals in ZDF rats. Of these changes, aerobic exercise training was able to correct R wave amplitude changes. In addition, exercise has beneficial effect in this diabetic rat model in regards to ECG correlates of left ventricular mass.

Physical exercise, fitness and dietary pattern and their relationship with circadian blood pressure pattern, augmentation index and endothelial dysfunction biological markers: EVIDENT study protocol

Background

Healthy lifestyles may help to delay arterial aging. The purpose of this study is to analyze the relationship of physical activity and dietary pattern to the circadian pattern of blood pressure, central and peripheral blood pressure, pulse wave velocity, carotid intima-media thickness and biological markers of endothelial dysfunction in active and sedentary individuals without arteriosclerotic disease.

Methods/Design

Design: A cross-sectional multicenter study with six research groups.

Subjects: From subjects of the PEPAF project cohort, in which 1,163 who were sedentary became active, 1,942 were sedentary and 2,346 were active. By stratified random sampling, 1,500 subjects will be included, 250 in each group.

Primary measurements: We will evaluate height, weight, abdominal circumference, clinical and ambulatory blood pressure with the Radial Pulse Wave Acquisition Device (BPro), central blood pressure and augmentation index with Pulse Wave Application Software (A-Pulse) and SphymgoCor System Px (Pulse Wave Analysis), pulse wave velocity (PWV) with SphymgoCor System Px (Pulse Wave Velocity), nutritional pattern with a food intake frequency questionnaire, physical activity with the 7-day PAR questionnaire and accelerometer (Actigraph GT3X), physical fitness with the cycle ergometer (PWC-170), carotid intima-media thickness by ultrasound (Micromax), and endothelial dysfunction biological markers (endoglin and osteoprotegerin).

Discussion

Determining that sustained physical activity and the change from sedentary to active as well as a healthy diet improve circadian pattern, arterial elasticity and carotid intima-media thickness may help to propose lifestyle intervention programs. These interventions could improve the cardiovascular risk profile in some parameters not routinely assessed with traditional risk scales. From the results of this study, interventional approaches could be obtained to delay vascular aging that combine physical exercise and diet.

Trial Registration

Clinical Trials.gov Identifier: NCT01083082

European Society of Hypertension International Protocol for the validation of blood pressure monitors: a critical review of its application and rationale for revision

OBJECTIVE

To perform a systematic review of validation studies of blood pressure measuring devices done using the European Society of Hypertension International Protocol (ESH-IP) since its publication in 2002.

METHODS

Major aspects of ESH-IP studies are described. A review of the ESH-IP performance, problems and violations in its application, and the effect of applying several more stringent validation criteria in an ESH-IP revision is carried out.

RESULTS

From January 2002 to June 2009, 104 validation studies had been conducted using the ESH-IP, 36 using the British Hypertension Society protocol and 28 using the US Association for the Advancement of Medical Instrumentation protocol. Among 78 studies reported up to June 2008, in 66 (85%) the tested device has passed the ESH-IP. In 19 validations a modification of the ESH-IP was performed to adapt for specific study needs (population or device). Protocol violations of the ESH-IP were identified in 23 studies (eight major violations). A test of several arbitrarily chosen changes in the ESH-IP validation criteria applied in the published studies showed the phase 2.1 criterion (BP differences < or =15 mmHg) and the phase 2.2 criteria to be the more stringent.

CONCLUSION

The ESH-IP has succeeded in expanding the validation procedure worldwide by three to four-fold compared with the period before its publication. There is a need for protocol revision aiming to address issues that appeared in published studies, prevent protocol violations, and ensure complete data reporting. Standardization of the ESH-IP validation studies' report and application of more stringent criteria should be considered.