Vascular Tonometry Research Articles

Hypertension-Mediated Organ Damage in Relation to Severity of Chronic Low Back Pain in Hypertensive Patients.

Chronic pain triggers a stress response, which results in increased blood pressure (BP). We investigated whether chronic low back pain (cLBP) in hypertensive patients is associated with an increased risk of hypertension-related organ damage. We studied 85 consecutive hypertensive patients with a median age of 62 years (55-67), who suffered from cLBP, the severity of which was evaluated according to the Oswestry Disability Index (ODI). Patients underwent transthoracic echocardiography, arterial ultrasonography and vascular tonometry. We assessed carotid artery atherosclerotic plaques, along with carotid-femoral pulse wave velocity (cf-PWV) and left ventricular mass index (LVMI). An equal to or higher than median (16 points) ODI score in 48 subjects (56.5%) was associated with the presence of carotid artery plaques (p = 0.014). In multivariate analysis, after adjusting for covariates, the presence of carotid artery plaques remained independently associated with an ODI score equal to or higher than the median (OR, 3.71; 95% CI, 1.04-13.25; p = 0.044). None of the other analyzed parameters of hypertension-related organ damage demonstrated a significant relationship with the ODI score. We observed that more severe cLBP is associated with a higher prevalence of carotid artery atherosclerotic plaques among hypertensive patients.

Blood Pressure Responses During Exercise: Physiological Correlates and Clinical Implications.

Abnormal blood pressure (BP) responses to exercise can predict adverse cardiovascular outcomes, but their optimal measurement and definitions are poorly understood. We combined frequently sampled BP during cardiopulmonary exercise testing with vascular stiffness assessment to parse cardiac and vascular components of exercise BP. Cardiopulmonary exercise testing with BP measured every two minutes and resting vascular tonometry were performed in 2858 Framingham Heart Study participants. Linear regression was used to analyze sex-specific exercise BP patterns as a function of arterial stiffness (carotid-femoral pulse wave velocity) and cardiac-peripheral performance (defined by peak O2 pulse). Our sample was balanced by sex (52% women) with mean age 54±9 years and 47% with hypertension. We observed variability in carotid-femoral pulse wave velocity and peak O2 pulse across individuals with clinically defined exercise hypertension (peak systolic BP [SBP] in men ≥210 mm Hg; in women ≥190 mm Hg). Despite similar resting SBP and cardiometabolic profiles, individuals with higher peak O2 pulse displayed higher peak SBP (P≤0.017) alongside higher fitness levels (P<0.001), suggesting that high peak exercise SBP in the context of high peak O2 pulse may in fact be favorable. Although both higher (favorable) O2 pulse and higher (adverse) arterial stiffness were associated with greater peak SBP (P<0.0001 for both), the magnitude of association of carotid-femoral pulse wave velocity with peak SBP was higher in women (sex-carotid-femoral pulse wave velocity interaction P<0.0001). In sex-specific models, exercise SBP measures accounting for workload (eg, SBP during unloaded exercise, SBP at 75 watts, and SBP/workload slope) were directly associated with the adverse features of greater arterial stiffness and lower peak O2 pulse. Higher peak exercise SBP reflects a complex trade-off between arterial stiffness and cardiac-peripheral performance that differs by sex. Studies of BP responses to exercise accounting for vascular and cardiac physiology may illuminate mechanisms of hypertension and clarify clinical interpretation of exercise BP.

4392 Comparative Analysis of Vascular Hemodynamics in a Young Biracial Cohort

OBJECTIVES/GOALS: We investigated hemodynamic measures in young black and white adults below the age of 50 years to identify mechanisms that may predispose blacks to more CVE. METHODS/STUDY POPULATION: We recruited 276 young blacks and white adults in Jackson, MS (mean age: 33 ± 9 years; 70% women; 57% Black;). Participants had clinical and vascular tonometry parameters obtained. Vascular measures included carotid femoral pulse wave velocity, central and peripheral pulse pressure (CPP and PPP), characteristic impedance (Zc), augmentation index, and forward pressure wave. Race-specific characteristic means and proportions were tested using Student’s T- or Chi-square tests. After further sex stratification, significant variation in characteristics among sex within race were tested using nested ANOVA. RESULTS/ANTICIPATED RESULTS: Characteristics of the study group stratified by race were found to be similar. Vascular measures stratified by race revealed blacks to have significantly higher Zc (p = 0.03) and PPP (p = 0.03) than whites. DISCUSSION/SIGNIFICANCE OF IMPACT: In this study of vascular hemodynamics in young black and white participants we found differences in Zc and PPP. Findings suggest that differing relations between proximal aortic diameter and wall stiffness may contribute to the racial disparity in CVE in adults. This finding could offer an explanation to the beneficial effects of treatment modalities that target aortic stiffness in blacks.

70-year legacy of the Framingham Heart Study.

The Framingham Heart Study (FHS) was established in 1948 to improve understanding of the epidemiology of coronary heart disease (CHD) in the USA. In 1961, seminal work identified major risk factors for CHD (high blood pressure, high cholesterol levels and evidence on the electrocardiogram of left ventricular hypertrophy), which later formed the basis for multivariable 10-year and 30-year risk-prediction algorithms. The FHS cohorts now comprise three generations of participants (n ≈ 15,000) and two minority cohorts. The FHS cohorts are densely phenotyped, with recurring follow-up examinations and surveillance for cardiovascular and non-cardiovascular end points. Assessment of subclinical disease and physiological profiling of these cohorts (with the use of echocardiography, ambulatory electrocardiographic monitoring, exercise stress testing, cardiac CT, heart and brain MRI, serial vascular tonometry and accelerometry) have been performed repeatedly. Over the past decade, the FHS cohorts have undergone deep 'omics' profiling (including whole-genome sequencing, DNA methylation analysis, transcriptomics, high-throughput proteomics and metabolomics, and microbiome studies). The FHS is a rich, longitudinal, transgenerational and deeply phenotyped cohort study with a sustained focus on state-of-the-art epidemiological methods and technological advances to facilitate scientific discoveries.

Correction: Quality of life measures predict cardiovascular health and physical performance in chronic renal failure patients.

[This corrects the article DOI: 10.1371/journal.pone.0183926.].

Abstract MP86: Hemodynamic and Metabolomic Change From Lifestyle Driven Weight Loss in Obese Adolescents

Background: While bariatric surgery is known to induce hemodynamic and metabolic pathway alterations, lifestyle-driven weight loss in obese adolescents are not well characterized with respect to hemodynamic and metabolomic effects. We studied aortic function and urine metabolomics changes in obese adolescent volunteers attending weight loss summer camps. Methods: Adolescents (n=45, 71% girls, mean age 15±1 year) attending long-standing weight loss camps over 3 summers volunteered to have weight, long term diet and activity history, and vascular tonometry after overnight fast at camp entry and exit. A subset (n=32) also gave urine entry and exit urine samples for metabolomic analysis (Metabolon, Durham NC). Camp administrators followed pre-existing protocols encouraging campers toward 5 hours or more of structured activity and free play as well as nutritionist-designed meal plan restricted to age-sex specific calorie goals. Paired students T-tests were used to assess changes in anthropometrics and hemodynamics. Osmolality-adjusted metabolomic changes were analyzed using principal components analysis; paired T-test with multiple comparison adjustment by Storey-Tibshirani false discovery rate thresholding; and Random Forest decision tree ensembles with selection of the top 30 biochemicals in variable importance gleaned from the Mean Decrease Accuracy metric, which randomly permutes a given chemical and reassesses predictive accuracy throughout the tree ensembles, and then grouped into pathway categories. Results: Median camp length was 6 weeks (25%,75% IQR 5,7). Campers on average lost body 11±4% of body weight (99±20 to 88±17 kilograms, p&lt;0.0001). Supine systolic blood pressure declined from 115±11 to 111±12 mmHg (p&lt;0.01), diastolic blood pressure from 57±8 to 52±7 mmHg (p&lt;0.0001), and heart rate from 73±10 to 62±11 beats per minute (p&lt;0.0001). Carotid femoral pulse wave velocity decreased from 5.4±0.7 to 5.1±0.6 meters per second (p&lt;0.0001). This change in arterial stiffness was not dependent on changes in heart rate nor distending pressure. Augmentation index did not significantly change from 17±11% to 16±9% (p=0.5). On urine metabolomic analysis, altered biochemical pathways included lipid metabolism, bile acids, and carbohydrate excretion. Conclusions: Diet and activity driven weight loss in excess weight adolescents is associated with salutary hemodynamic improvement and specific metabolic alterations, paralleling findings after bariatric surgery. More investigation into the mechanisms of lifestyle driven weight loss is warranted.

Erratum to: Pulse pressure: more than 100 years of changes in stroke volume

Incorrect: Dufour et al. [22], in their paper in this issue, take the concept one step further forward. They demonstrated that PLR can be performed in a completely non-invasive way using vascular tonometry. Correct: Dufour et al. [22], in their paper in this issue, take the concept one step further forward. They demonstrated that changes in SV can be tracked in a completely non-invasive way using vascular tonometry.