Relationship between augmentation index and flow-mediated vasodilation in the brachial artery

Endothelial function and endothelial progenitor cells in systemic lupus erythematosus

The observations that traditional cardiovascular disease (CVD) risk factors fail to fully account for the excessive cardiovascular mortality in patients with systemic lupus erythematosus (SLE) compared with the general population have prompted in-depth investigations of non-traditional, SLE-related risk factors that contribute to cardiovascular complications in patients with SLE. Of the various perturbations of vascular physiology, endothelial dysfunction, which is believed to occur in the earliest step of atherosclerosis, has been extensively investigated for its contribution to CVD risk in SLE. Endothelial progenitor cells (EPCs), which play a crucial part in vascular repair, neovascularization and maintenance of endothelial function, are quantitatively and functionally reduced in patients with SLE. Yet, the lack of a unified definition of EPCs, standardization of the quantity and functional assessment of EPCs as well as endothelial function measurement pose challenges to the translation of endothelial function measurements and EPC levels into prognostic markers for CVD in patients with SLE. This Review discusses factors that contribute to CVD in SLE, with particular focus on how endothelial function and EPCs are evaluated currently, and how EPCs are quantitatively and functionally altered in patients with SLE. Potential strategies for the use of endothelial function measurements and EPC quantification as prognostic markers of CVD in patients with SLE, and the limitations of their prognostication potential, are also discussed.

Comparison of the usefulness of the cardio-ankle vascular index and augmentation index as an index of arteriosclerosis in patients with essential hypertension

Arteriosclerosis leads to various serious diseases that substantially reduce the quality of life. When treating hypertension, it is important to evaluate the degree of arteriosclerosis. In recent years, the cardio-ankle vascular index and augmentation index have been frequently used as indicators of arterial wall sclerosis. However, the superiority of either the cardio-ankle vascular index or the augmentation index as an index of arteriosclerosis remains unclear. Therefore, the present study compared the usefulness of these two indices as an index of arteriosclerosis. Associations between the cardio-ankle vascular index or augmentation index and risk factors for arteriosclerosis and other indices of arteriosclerosis in 535 consecutive patients with essential hypertension were evaluated. The cardio-ankle vascular index was significantly correlated with age, hemoglobin A1c, brain natriuretic peptide, and estimated glomerular filtration rate. In contrast, the augmentation index showed significant correlations only with age, brain natriuretic peptide, and estimated glomerular filtration rate. In addition, these correlations with the augmentation index were generally weaker than those with the cardio-ankle vascular index. The cardio-ankle vascular index, but not the augmentation index, was significantly correlated with flow-mediated dilation, an index of vascular endothelial function, and carotid intima-media thickness, an index of carotid atherosclerosis. Similar results were observed in subgroups stratified by sex and age. These data indicate that the cardio-ankle vascular index is more closely associated with risk factors for arteriosclerosis and other indices of arteriosclerosis than the augmentation index, suggesting that the cardio-ankle vascular index may be superior to the augmentation index as an index of arteriosclerosis.

Augmentation Index Predicts the Sweat Volume in Young Runners

Sweating during exercise is regulated by objective parameters, body weight, and endothelial function, among other factors. However, the relationship between vascular arterial stiffness and sweat volume in young adults remains unclear. This study aimed to identify hemodynamic parameters before exercise that can predict sweat volume during exercise, and post-exercise parameters that can be predicted by the sweat volume. Eighty-nine young healthy subjects (aged 21.9 ± 1.7 years, 51 males) were recruited to each perform a 3-km run on a treadmill. Demographic and anthropometric data were collected and hemodynamic data were obtained, including heart rate, blood pressure and pulse wave analysis using non-invasive tonometry. Sweat volume was defined as pre-exercise body weight minus post-exercise body weight. Post-exercise hemodynamic parameters were also collected. Sweat volume was significantly associated with gender, body surface area (BSA) (b = 0.288, p = 0.010), peripheral systolic blood pressure (SBP), peripheral and central pulse pressure (PP), and was inversely associated with augmentation index at an HR of 75 beats/min (AIx@HR75) (b = -0.005, p = 0.019) and ejection duration. While BSA appeared to predict central PP (B = 19.271, p ≤ 0.001), central PP plus AIx@HR75 further predicted sweat volume (B = 0.008, p = 0.025; B = -0.009, p = 0.003 respectively). Sweat volume was associated with peripheral SBP change (B = -17.560, p = 0.031). Sweat volume during a 3-km run appears to be influenced by hemodynamic parameters, including vascular arterial stiffness and central pulse pressure. Results of the present study suggest that vascular arterial stiffness likely regulates sweat volume during exercise.

Brachial Flow-Mediated Dilation and Risk of Atrial Fibrillation in Older Adults: The Cardiovascular Health Study

Background

Endothelial dysfunction is associated with common risk factors for AF and has been implicated in the pathophysiology of atrial fibrillation (AF) through a variety of mechanisms. We determined the prospective association of brachial flow-mediated dilation (FMD) with incident AF among older adults.

Methods

We included 2027 Cardiovascular Health Study participants (mean age=78.3 years, male=39%, Black=17%) who underwent brachial FMD measurement at the 1997 to 1998 clinic visit. Incident AF was ascertained by study electrocardiograms, hospital discharge diagnosis coding and Medicare claims data. Cox regression models were used to examine the association between FMD and incident AF.

Results

We identified 754 incident of AF cases (37%) over a median follow-up of 11.0 years. After adjusting for age, sex, race, height, weight, cardiovascular disease, cigarette smoking, hypertension, diabetes, kidney function, c-reactive protein, physical activity, alcohol consumption, and statins, the risk of AF did not differ according to brachial FMD response (4th vs 1st quartile hazard ratio (HR)=1.01, 95% confidence interval (CI): 0.81, 1.26; per FMD unit increment HR=1.01, 95% CI: 0.97, 1.05).

Conclusion

We found no relationship between brachial FMD and the risk of developing AF in this elderly cohort. Our findings suggest that the utility of brachial FMD as a risk marker for AF in older individuals is minimal.

Arterial function in hypertensive pregnant women. Is arterial stiffness a marker for the outcomes in pregnancy?

AIMS

Hypertension (HTN) in pregnancy is a major cause of maternal, foetal and neonatal morbimortality in both developing and developed countries. Arterial stiffness is a predictor of cardiovascular events and can be assessed through augmentation index (AIx) and pulse wave velocity (PWV). This study was intended to analyse the arterial stiffness in three categories, hypertensive pregnant women vs. healthy women (both pregnant and non-pregnant).

MAIN METHODS

Between 2018 and 2019, 150 women were prospectively included into three homogenous groups, of equal sizes (N = 50): pregnant women with HTN (group 1), pregnant women without HTN (group 2), and non-pregnant women (group 3). We assessed pregnant women 3 times (in all three trimesters) and six weeks postpartum, and the women from the control group once.

KEY FINDINGS

Significant differences (p < 0.001) of the hemodynamic and arterial stiffness parameters and of the heart rate (HR) (p = 0.006) were observed between groups 1 and 2. Women with pregnancy-induced HTN had different values of arterial function parameters long time before the first signs of high blood pressure (BP) occurred. Also, body mass index (BMI) had a deleterious effect in all patients, but especially in pregnant HTN women. Significant differences (p < 0.001) between groups 2 and 3 were observed regarding the BP and aortic PWV (PWVao) and, as well, significant differences (p < 0.05) between BMI, aortic systolic BP (p = 0.02), brachial AIx (p = 0.01) and pulse pressure (PP) (p = 0.049) values.

SIGNIFICANCE

The current study emphasizes the importance of the assessment of arterial function parameters and BMI as markers for future BP values and outcomes throughout gestation.

Endothelial Function and Oxidative Stress in X-Linked, gp91phox Deficiency, Chronic Granulomatous Disease

Two patients with X-linked chronic granulomatous disease without NAPDH oxidase activity and with high responses of flow-mediated vasodilation are reported. Bone marrow transplantation restored oxidative stress to the levels of those in healthy subjects and decreased flow-mediated vasodilation to the levels of those in healthy subjects in both of the patients. (Level of Difficulty: Advanced.).

Cardiorespiratory fitness predicts cardiovascular health in breast cancer survivors, independent of body composition, age and time post-treatment completion

BACKGROUND

Breast cancer treatment may increase non-cancer related mortality risk due to unintended cardiovascular consequences. The aim of this study was to investigate the strongest correlate of cardiovascular health (CVH) in female breast cancer survivors, cardiorespiratory fitness or fatness.

METHODS

Fifty-one women (59 ± 9 years, BMI 26.4 ± 4.8 kg/m²) previously diagnosed and treated for primary breast cancer were assessed using pulse wave analysis to determine central arterial wave reflection (augmentation index, AIx) and central systolic blood pressure (cSBP). A composite Z score calculated which incorporated central double product and AIx, as an indicator of CVH. Dual energy X-ray absorptiometry was used to obtain total body fat percentage (BF%). Cardiorespiratory fitness was determined using the single-stage walk test to predict maximal oxygen uptake ([Formula: see text]).

RESULTS

Linear regression analysis revealed that fitness was associated with AIx after adjusting for BF %, age and time post-treatment completion (β = - 0.271, p = 0.010). A significant association between BF% and AIx after adjusting for fitness and age was found (β = 0.166, p = 0.0005); however, this association was lost when time post-treatment was included in the model (β = 0.166, p = 0.167). Both fitness (β = - 0.347, p = 0.0005) and BF% (β = 0.333, p = 0.013) were independently associated with CVH in the fully adjusted model.

CONCLUSIONS

This study provides evidence for an association between cardiorespiratory fitness and cardiovascular health in female breast cancer survivors. While fatness may be associated with cardiovascular health, it appears to be more strongly associated with age.

Radial Artery Tonometry is Associated With Major Adverse Cardiac Events in Patients With Peripheral Artery Disease

BACKGROUND

Peripheral artery disease (PAD) is associated with increased arterial stiffness, as measured by an increasing radial artery augmentation index (AIX). However, it has not yet been clearly demonstrated whether AIX is associated with adverse cardiovascular outcomes in a PAD population.

MATERIALS AND METHODS

Seventy-two patients with PAD were recruited between 2011 and 2016. Radial artery applanation tonometry was performed at a baseline visit, and the central AIX, normalized to 75 beats/min, and the peripheral AIX were calculated using pulse wave analysis. Incident major adverse cardiac events (MACEs) were identified by subsequent chart review.

RESULTS

Study subjects had comorbidities commonly associated with PAD including a high prevalence of hypertension (93%), hyperlipidemia (85%), coronary artery disease (39%), and diabetes mellitus (39%). During a median follow-up period of 34 mo (interquartile range 29-38), 14 patients experienced a MACE. In a univariate Cox proportional hazards model, a 10-unit increase in the peripheral AIX was significantly associated with a 54% increased rate of MACE (hazard ratio [HR] 1.54, 95% confidence interval [CI] 1.06-2.22, P = 0.02), but central AIX, normalized to 75 beats/min, was not (HR 1.33, 95% CI 0.71-2.47, P = 0.37). In a multivariable model adjusted for coronary artery disease, age, and Rutherford category the peripheral AIX remained significantly associated with MACE (HR 1.70, 95% CI 1.10-2.62, P = 0.02).

CONCLUSIONS

Increased arterial stiffness, as measured by the peripheral AIX, was independently associated with an increased rate of MACE in patients with PAD. The use of radial artery tonometry should be contemplated as a tool for risk stratification in patients with PAD.

Factors Associated with the Risk of Developing Coronary Artery Disease in Medicated Patients with Major Depressive Disorder

Background: The aim of this study was to identify factors associated with high Framingham Risk Score (FRS) in medicated patients with major depressive disorder (MDD). Methods: We examined 61 medicated patients with MDD (mean age 37.77 ± 7.67, 90.2% women) and 43 non-depressed controls (mean age 38.26 ± 9.20, 90.7% women). We administered the Hamilton Depression Rating Scale (HAM-D) and measured systolic blood pressure (SBP), diastolic BP (DBP), mean arterial BP (MAP), pulse wave velocity (PWV), intima-media thickness (IMT), interleukin-6 (IL-6) and triglycerides. Results: We found that medicated patients with MDD had significantly higher levels of HAM-D score (p < 0.01), SBP (p = 0.015), MAP (p = 0.037), IL−6 level (p = 0.007), as compared with controls. Medicated patients who remained moderately to severely depressed showed significantly higher SBP (p = 0.049), DBP (p = 0.009), MAP (p = 0.024), IL−6 level (p = 0.019), left PWV (p = 0.004) and average PWV (p = 0.026) than those with mild depression. Multivariate regression showed that the interaction effect between HAM-D score and triglyceride level (p = 0.018) was significantly associated with FRS in medicated patients with MDD. Conclusions: This study highlights that the interaction effect of the severity of depression and the triglyceride level, was a modifiable factor positively associated with high FRS.

Characterizing the relationship between flow-mediated vasodilation and radial artery tonometry in peripheral artery disease

BACKGROUND

Arterial stiffness, measured by the augmentation index (AIX) from radial artery tonometry, and endothelial dysfunction, measured by brachial-artery flow-mediated vasodilation (FMD), have each been associated with increased risk of cardiovascular events. However, their interrelationship in peripheral artery disease (PAD) patients is poorly understood.

MATERIALS AND METHODS

In a cross-sectional analysis of 123 vascular surgery outpatients, the association between FMD and AIX was examined in controls with atherosclerotic risk factors (n = 32) and patients with PAD (n = 91). PAD was defined as claudication symptoms with an ankle-brachial index of <0.9 or a history of revascularization for symptomatic PAD. Controls had an ankle-brachial index ≥0.9 and no history of atherosclerotic vascular disease.

RESULTS

Compared to controls, patients with PAD had lower FMD (6.3 ± 3.8 versus 8.4 ± 3.7, P = 0.008), while central AIX normalized to 75 beats per minute (25.5 ± 9.0 versus 19.3 ± 8.6, P = 0.001) and peripheral AIX (91.3 ± 14.5 versus 81.3 ± 11.4, P = 0.001) were higher. FMD was not significantly correlated with either central or peripheral AIX (central AIX: P = 0.58; peripheral AIX: P = 0.89) across the entire cohort, or in either the patients with PAD (central AIX: P = 0.48; peripheral AIX: P = 0.23) or controls (central AIX: P = 0.43; peripheral AIX: P = 0.92). In a multivariate model including FMD, higher AIX remained independently associated with PAD.

CONCLUSIONS

In an analysis of vascular surgery outpatients, no correlation between FMD and AIX was detected. Larger prospective studies are needed to determine whether the inclusion of both parameters improves predictive models for the early identification and potential risk stratification of PAD patients.

Relationship Between Serum Total Testosterone Concentration and Augmentation Index at Radial Artery in Japanese Postmenopausal Patients

Background

The significance of testosterone as a risk factor for cardiovascular disease (CVD) in females is controversial. This cross-sectional study aimed to elucidate the relationship between serum total testosterone concentration (T-T) and augmentation index at the radial artery (r-AIx) as a marker of arterial function in Japanese postmenopausal patients.

Methods

A total of 447 postmenopausal patients with traditional cardiovascular risk factors and/or a history of CVD (age (mean ± standard deviation (SD)), 73 ± 10 years) were enrolled. r-AIx was measured using tonometry, and the association between r-AIx and various clinical parameters, including T-T, was determined.

Results

r-AIx significantly increased (CVD vs. non-CVD: 99±11% vs. 91±11%, P < 0.001) and T-T significantly decreased (CVD vs. non-CVD: 0.31 ± 0.13 ng/mL vs. 0.49 ± 0.23 ng/mL, P < 0.001) in patients with CVD than in those without CVD. A significant negative correlation (r = -0.48; P < 0.001) between r-AIx and T-T was observed. Furthermore, multiple regression analysis indicated that T-T (t value = -7.7; P < 0.001), height (t value = -5.3; P < 0.001), d-ROMs test as a marker of oxidative stress in vivo (t value = 3.2; P < 0.001), CVD (t value = 2.9; P < 0.01), and pulse rate (t value = -2.7; P < 0.01) were independent variables for r-AIx as a subordinate factor.

Conclusion

This study revealed that low T-T is an important determining factor for an increase in r-AIx in Japanese postmenopausal patients. A prospective multicenter study with a large sample size is required to confirm the results of this study.

Arterial Velocity Pulse Index as a Novel Marker of Atherosclerosis Using Pulse Wave Analysis on High Sensitivity Troponin T in Hypertensive Patients

Background

The arterial velocity pulse index (AVI) is explored as a novel marker of atherosclerosis using pulse wave analysis in clinical settings. Recent clinical studies have reported that the level of high-sensitivity troponin T (hs-cTnT) is an important biomarker in hypertensive patients. The aim of this study was to clarify the impact of AVI on hs-cTnT in these patients.

Methods

This study enrolled 455 hypertensive outpatients (181 males and 274 females; mean age, 65 ± 11 years (mean ± standard deviation)) without a history of cardiovascular events. AVI and hs-cTnT levels were measured using a commercial device, and relations among various clinical parameters, including AVI and hs-cTnT, were examined.

Results

Hs-cTnT was detected in 405 patients (89.0%). AVI was significantly higher in patients with detectable hs-cTnT than in those without (28 ± 7 vs. 24 ± 8, respectively, P < 0.001). In patients with detectable hs-cTnT, there was a significant positive correlation between AVI and hs-cTnT (r = 0.42, P < 0.001). Furthermore, multiple regression analyses revealed that AVI was an independent variable when hs-cTnT was used as a subordinate factor. On the other hand, hs-cTnT age, Cornell electrocardiographic voltage, height, urinary albumin excretion, pulse rate, and derivatives of reactive oxygen metabolites test were independent variables when AVI was used as a subordinate factor.

Conclusion

The results of this study indicate that AVI reflects features of arterial wave reflection and is an important factor for hs-cTnT elevation in hypertensive patients.

Augmentation index (AI) in a dose-response relationship with smoking habits in males: The Tanushimaru study

We investigated the relationship between augmentation index (AI) and smoking habits in community-dwelling Japanese.This cross-sectional study enrolled 1926 subjects (769 males and 1157 females) aged 40 to 95 years who underwent a health check-up in a Japanese cohort of the Seven Countries Study, in Tanushimaru, a typical farming town in Kyushu Island in 2009. The subjects' medical history, alcohol intake, smoking habit, and current medications for hypertension, dyslipidemia, and diabetes were ascertained by questionnaire. Radial arterial pressure wave analysis was used to obtain AI. We analyzed the data stratified by gender.Age-adjusted means of AI in males showed a clear dose-response relationship in 4 categories of smoking habits (P = 0.010). There was no significant relationship between AI and smoking habits in females (P = 0.127). The significant dose-response relationship (P = 0.036) in males between AI and 4 categories of smoking habits still remained even after adjustment for age, body mass index, systolic blood pressure, estimated glomerular filtration rate, glucose, hypertensive medication, and alcohol intake.The present study demonstrated that AI values were significantly associated with smoking habits in a dose-dependent manner in Japanese males.

Factors Associated with High-sensitivity Cardiac Troponin T in Patients with Type 2 Diabetes Mellitus

BACKGROUND

The blood concentration of high-sensitivity cardiac troponin T (hs-cTnT) is an established, useful biomarker for evaluating the pathogenesis of heart failure and predicting cardiovascular events. The aim of this study was to evaluate factors that are potentially associated with elevated blood hs-cTnT in patients with type 2 diabetes mellitus.

PATIENTS AND METHODS

Patients with type 2 diabetes mellitus (N=280, 111 men and 169 women; mean ± SD age: 71±9 years) with no history of cardiovascular events were enrolled. Relationships between hs-cTnT level and various clinical parameters were examined.

RESULTS

Hs-cTnT was detected in 244 (87.1%) patients. There were no significant relationships between hs-cTnT and fasting blood glucose levels or insulin resistance. hs-cTnT was significantly correlated with advanced glycation end-product levels at the skin (r=0.23, p<0.001), blood concentrations of brain natriuretic peptide (r=0.23, p<0.001), reactive oxygen metabolites as markers of oxidative stress (r=0.28, p<0.001), and the augmentation index at the radial artery as marker of arterial reflection (r=0.31, p<0.001). Furthermore, multiple regression analysis revealed that these factors were also selected as independent variables, with hs-cTnT as a subordinate factor.

CONCLUSION

These results indicate that novel cardiovascular risk factors including advanced glycation end-products, in vivo oxidative stress, and high arterial reflection are closely associated with high concentrations of blood hs-cTnT in patients with type 2 diabetes mellitus.

Reliability of oscillometric central blood pressure responses to submaximal exercise

BACKGROUND

Central blood pressure responses to exercise may provide clinicians with a superior diagnostic and prognostic tool. However, to be of value in a clinical setting these assessments must be simple to conduct and reliable.

OBJECTIVE

Using oscillometric pulse wave analysis (PWA), determine the upper limit for between-day reliability of central SBP (cSBP) and central pressure augmentation (AIx) responses to three progressive stages of submaximal exercise in a cohort of young, healthy participants.

METHODS

Fifteen healthy males [25.8 years (SD 5.7), 23.9 kg/m (SD 2.5)] were tested on three different mornings in a fasted state, separated by a maximum of 14 days. Central hemodynamic variables were assessed on the left upper arm. Participants underwent three progressive stages of submaximal cycling at 50 W (low), 100 W (moderate) and 150 W (moderate-hard).

RESULTS

During low and moderate-intensity exercise the intra-class correlation coefficient (ICC) values for cSBP (0.79-0.80) and AIx (0.81-0.85) indicated excellent reliability (ICC > 0.75). For the moderate-hard intensity AIx could not be computed, and the ICC for cSBP was adequate (0.72).

CONCLUSION

Findings from this study suggest that, at least in a young, healthy cohort, oscillometric PWA can be used to reliably assess central blood pressure measurements during exercise, up to a moderate intensity. Although further work is required to verify these findings in clinical cohorts, these measurements may potentially provide clinicians with a practical option for obtaining important hemodynamic information beyond that provided by resting peripheral blood pressure.

Reliability of oscillometric central blood pressure and wave reflection readings: effects of posture and fasting

OBJECTIVE

Oscillometric pulse wave analysis devices have recently emerged, presenting suitable options for investigating central hemodynamic properties in clinical practice. This study sought to examine whether the between-day reliability of central SBP (cSBP) and systemic arterial wave reflection (augmentation index, AIx) readings exceed the criterion for acceptable reliability or are affected by posture (supine and seated) and fasting state.

METHODS

Twenty healthy adults (50% female, 27.9 years, 24.2 kg/m) were tested on six different mornings: 3 days fasted and 3 days nonfasted. On each occasion, participants were tested in supine and seated postures. Oscillometric pressure waveforms were recorded on left upper arm.

RESULTS

For cSBP, there was nonsignificant main effect for fasting state (P = 0.819) but there was a main effect for posture (P = 0.002). Conversely, for AIx, there was nonsignificant main effect for posture (P = 0.537) but there was a large main effect for fasting state (P = < 0.001). The criterion intraclass correlation coefficient value of 0.75 was exceeded for both variables when participants were assessed under the combined supine-fasted condition. For cSBP, the reliability coefficient was lowest (best) when supine fasted (6.8 mmHg) and greatest (worst) when seated nonfasted (8.6 mmHg). For AIx, the reliability coefficient was lower for the supine (11.4-11.7%) compared with the seated (14.0-15.2%) posture.

CONCLUSION

Findings from this study suggest that oscillometric assessments of central hemodynamic variables exceed the criterion for acceptable reliability and are most reliable when participants are evaluated while supine and fasted.

Reliability of oscillometric central hemodynamic responses to an orthostatic challenge

BACKGROUND

Monitoring central hemodynamic responses to an orthostatic challenge may provide important insight into autonomic nervous system function. Oscillometric pulse wave analysis devices have recently emerged, presenting clinically viable options for investigating central hemodynamic properties. The purpose of the current study was to determine whether oscillometric pulse wave analysis can be used to reliably (between-day) assess central blood pressure and central pressure augmentation (augmentation index) responses to a 5 min orthostatic challenge (modified tilt-table).

METHODS

Twenty healthy adults (26.4 y (SD 5.2), 55% F, 24.7 kg/m(2) (SD 3.8)) were tested on 3 different mornings in the fasted state, separated by a maximum of 7 days. Central hemodynamic variables were assessed on the left arm using an oscillometric device.

RESULTS

Repeated measures analysis of variance indicated a significant main effect of the modified tilt-table for all central hemodynamic variables (P < 0.001). In response to the tilt, central diastolic pressure increased by 4.5 mmHg (CI: 2.6, 6.4), central systolic blood pressure increased by 2.3 (CI: 4.4, 0.16) mmHg, and augmentation index decreased by an absolute - 5.3%, (CI: -2.7, -7.9%). The intra-class correlation coefficient values for central diastolic pressure (0.83-0.86), central systolic blood pressure (0.80-0.87) and AIx (0.79-0.82) were above the 0.75 criterion in both the supine and tilted positions, indicating excellent between-day reliability.

CONCLUSION

Central hemodynamic responses to an orthostatic challenge can be assessed with acceptable between-day reliability using oscillometric pulse wave analysis.

Abnormal pressure-wave reflection in pregnant women with chronic hypertension: association with maternal and fetal outcomes

The current study tested the hypothesis that abnormal pressure-wave reflection may have an important role in identifying pregnant women with chronic hypertension who might develop pre-eclampsia (PE) and/or fetal growth restriction. Pulse-wave analyses were performed to assess maternal arterial stiffness during 26-32 weeks of gestation in 41 women with chronic hypertension. We measured the central systolic pressure (CSP) and augmentation index (AIx) noninvasively using pulse waveforms of the radial artery with an automated applanation tonometric system. In a multiple regression analysis that included AIx-75 (AIx at a heart rate of 75 beats per minute), brachial systolic pressure, maternal height, smoking status, gestational age at testing and the presence of antihypertensive treatment at testing as independent determinants, AIx-75 was the only significant determinant of birth weight, whereas the brachial systolic pressure was not. In pregnant women with chronic hypertension who subsequently developed both superimposed PE and fetal growth restriction, CSP, AIx, AIx-75, and the brachial systolic and pulse pressures were all significantly higher than those who did not develop superimposed PE nor small for gestational age. In contrast, AIx-75 was the only significantly elevated hemodynamic parameter in patients who developed fetal growth restriction but not superimposed PE. In addition, CSP was the only significantly elevated hemodynamic parameter in patients who developed superimposed PE but not fetal growth restriction. Abnormal pressure-wave reflection during 26-32 weeks of gestation showed a stronger correlation with birth weight than conventional brachial blood pressure. Our findings might provide new insight into the pathophysiology of fetal growth restriction as well as superimposed PE in pregnancies complicated with chronic hypertension.

Short-term physical inactivity impairs vascular function

BACKGROUND

Sedentarism, also termed physical inactivity, is an independent risk factor for cardiovascular diseases. Mechanisms thought to be involved include insulin resistance, dyslipidemia, hypertension, and increased inflammation. It is unknown whether changes in vascular and endothelial function also contribute to this excess risk. We hypothesized that short-term exposure to inactivity would lead to endothelial dysfunction, arterial stiffening, and increased vascular inflammation.

METHODS

Five healthy subjects (four men and one woman) underwent 5 d of bed rest (BR) to simulate inactivity. Measurements of vascular function (flow-mediated vasodilation to evaluate endothelial function; applanation tonometry to assess arterial resistance), inflammation, and metabolism were made before BR, daily during BR, and 2 d after BR recovery period. Subjects maintained an isocaloric diet throughout.

RESULTS

BR led to significant decreases in brachial artery and femoral artery flow-mediated vasodilation (brachial: 11 ± 3% pre-BR versus 9 ± 2% end-BR, P = 0.04; femoral: 4 ± 1% versus 2 ± 1%, P = 0.04). The central augmentation index increased with BR (-4 ± 9% versus 5 ± 11%, P = 0.03). Diastolic blood pressure increased (58 ± 7 mm Hg versus 62 ± 7 mm Hg, P = 0.02), whereas neither systolic blood pressure nor heart rate changed. 15-Hydroxyeicosatetraenoic acid, an arachidonic acid metabolite, increased but the other inflammatory and metabolic biomarkers were unchanged.

CONCLUSIONS

Our findings show that acute exposure to sedentarism results in decreased endothelial function, arterial stiffening, increased diastolic blood pressure, and an increase in 15-hydroxyeicosatetraenoic acid. We speculate that inactivity promotes a vascular "deconditioning" state characterized by impaired endothelial function, leading to arterial stiffness and increased arterial tone. Although physiologically significant, the underlying mechanisms and clinical relevance of these findings need to be further explored.

Sex differences between vascular endothelial function and carotid intima-media thickness by Framingham Risk Score

OBJECTIVES

To investigate sex differences associated with changes in brachial artery flow-mediated dilatation and carotid intima-media thickness by Framingham Risk Score.

METHODS

The study included 1083 patients aged 30 to 80 years. According to the Framingham Risk Score, patients were divided into 3 groups: low, mid, and high risk. Traditional cardiovascular risk factors such as age, sex, smoking, diabetes, hypertension, and cholesterol were assessed by Framingham Risk Score, as well as laboratory and vascular parameters, including flow-mediated dilatation and intima-media thickness. Correlations between flow-mediated dilatation, intima-media thickness, and the Framingham Risk Score were analyzed by sex.

RESULTS

Compared with women, flow-mediated dilatation in men was significantly lower in the low-risk group (mean ± SD, 8.31% ± 2.89% versus 9.76% ± 3.62%; P< .001) but significantly higher in the mid- and high-risk groups (mid-risk, 7.43% ± 2.65% versus 6.67% ± 2.42%; high-risk, 6.41% ± 2.27% versus 5.78% ± 2.39%; P< .001). Flow-mediated dilatation decreased with an increasing Framingham Risk Score in both sexes but especially in women. Although intima-media thickness increased with the Framingham Risk Score in both sexes, there was no significant sex difference between the groups. Univariate analysis showed significant negative correlations between flow-mediated dilatation and the Framingham Risk Score in both sexes (R men = -0.308; P < .001; R women = -0.572; P < .001) and flow-mediated dilatation and intima-media thickness (R men = -0.295; P < .001; R women = -0.474; P< .001). There was a significant positive correlation between intima-media thickness and the Framingham Risk Score (R men = 0.571; P< .001; R women = 0.633; P < .001).

CONCLUSIONS

A sex difference existed only for flow-mediated dilatation at the same Framingham risk level. Flow-mediated dilatation might be more sensitive than intima-media thickness for detecting sex differences in vascular dysfunction, according to Framingham risk stratification in a Chinese population.

Associations between short-term changes in air pollution and correlates of arterial stiffness: The Veterans Affairs Normative Aging Study, 2007-2011

We investigated associations between short-term exposure to air pollution and central augmentation index and augmentation pressure, correlates of arterial stiffness, in a cohort of elderly men in the Boston, Massachusetts, metropolitan area. This longitudinal analysis included 370 participants from the Veterans Affairs Normative Aging Study with up to 2 visits between 2007 and 2011 (n = 445). Augmentation index (as %) and augmentation pressure (in mmHg) were measured at each visit by using radial artery applanation tonometry for pulse wave analysis and modeled in a mixed effects regression model as continuous functions of moving averages of air pollution exposures (over 4 hours and 1, 3, 7, and 14 days). The results suggest that short-term changes in air pollution were associated with augmentation index and augmentation pressure at several moving averages. Interquartile range (IQR) increases in 3-day average exposure to particles with aerodynamic diameter less than 2.5 μm (3.6-μg/m(3) IQR increase) and sulfate (1.4-μg/m(3) IQR increase) and 1-day average exposure to particle number counts (8,741-counts/cm(3) IQR increase) were associated with augmentation index values that were 0.8% (95% confidence interval (CI): 0.2, 1.4), 0.6% (95% CI: 0.1, 1.2), and 1.7% (95% CI: 0.4, 2.9) higher, respectively. Overall, the findings were similar for augmentation pressure. The findings support the hypothesis that exposure to air pollution may affect vascular function.

Maternal arterial stiffness in normotensive pregnant women who subsequently deliver babies that are small for gestational age

OBJECTIVE

To assess the association between maternal arterial stiffness and delivery of a baby that is small for gestational age (SGA) in normotensive pregnant women.

STUDY DESIGN

Pulse wave analyses were performed to assess maternal arterial stiffness at 26-33 weeks of gestation in 40 normotensive women who subsequently delivered SGA babies (SGA group) and 111 normotensive women who delivered babies with normal growth (control group).

RESULTS

Central systolic pressure (CSP), augmentation index (AIx) and AIx at a heart rate of 75 beats/min (AIx-75) were significantly higher in the SGA group compared with the control group, but this was not the case for brachial systolic pressure, brachial diastolic pressure or brachial pulse pressure. Birth weight was significantly correlated with CSP (r=-0.26, p<0.01), AIx (r=-0.33, p<0.01) and AIx-75 (r=-0.27, p<0.01), but not with brachial systolic pressure, brachial diastolic pressure or brachial pulse pressure.

CONCLUSION

Increased arterial stiffness may be involved, in part, in the pathogenesis of SGA in normotensive women, suggesting an association between fetal growth and maternal endothelial function. Pulse wave analysis may be a clinically applicable method for assessment of maternal arterial stiffness, and may be more relevant to intrauterine fetal growth than conventional brachial blood pressure.

Central aortic blood pressure and augmentation index during normal pregnancy

The current study tested the hypothesis that pregnancy-related changes are more pronounced in central hemodynamics, and both central aortic systolic blood pressure (cSBP) and augmentation index (AIx) are independent from brachial systolic blood pressure (bSBP) in normal pregnant subjects. In 830 healthy pregnant women from 12 to 36 weeks gestation, we measured cSBP and AIx-75 (AIx at heart rate of 75 beats per minute) non-invasively by pulse waveforms of the radial artery using an automated applanation tonometric system. In 69 pregnant women, we recorded these data longitudinally. cSBP and AIx-75 significantly declined during pregnancy, reaching its nadir in mid-pregnancy and rising towards term. Pregnancy-related changes were more pronounced in AIx-75 compared with cSBP, but less evident in bSBP. AIx-75, but not cSBP, was independent from bSBP throughout pregnancy. cSBP and AIx-75, but not bSBP, were significantly increased in healthy pregnant women older than 35 years. This study established normal values for pulse wave analysis parameters throughout pregnancy, and indicated that pulse wave analysis might offer additional and independent information about maternal arterial compliance to conventional brachial blood pressure measurements. These data may be used as the basis for further investigation into the role of pulse wave analysis in the assessment, management and prediction of disorders, which might interfere with pregnancy-related cardiovascular adaptations.

Augmentation index association with reactive hyperemia as assessed by peripheral arterial tonometry in hypertension

BACKGROUND

Augmentation pressure has emerged as a surrogate marker for cardiovascular disease, and endothelial dysfunction has been proposed as related factor. However, the relationship between augmentation pressure and digital endothelial function has not yet been well defined. We investigated the relationship between augmentation pressure and digital reactive hyperemia (RH) in patients with hypertension using peripheral arterial tonometry (PAT), which is regarded as being representative of endothelial function.

METHODS

One hundred hypertensive patients (64 males; mean age, 49 ± 12 years) without a history of taking antihypertensive medication were enrolled in this study.

RESULTS

The mean augmentation pressure and augmentation index (AIx) normalized for a heart rate of 75 beats/min (AIx75) were 15 ± 8 mm Hg and 26 ± 11%, respectively. The mean RH-PAT index and log transformed PAT ratio were 2.24 ± 0.55 and 0.62 ± 0.30. There was an inverse relationship between the RH-PAT index and age, male sex, and body mass index. The log transformed PAT ratio also showed inverse relationship with age and male sex. The RH-PAT index and the log transformed PAT ratio showed no relationship with augmentation pressure or AIx75. In a multiple linear regression analysis, age, height, and central systolic BP demonstrated an independent association with augmentation pressure and AIx75.

CONCLUSION

In patients with hypertension, the RH-PAT index determined using PAT was not associated with augmentation pressure or AIx75. Digital vascular function may be a less important factor for pressure augmentation in patients with hypertension.

Effects of smoking cessation on central blood pressure and arterial stiffness

PURPOSE

Smoking affects arterial stiffness, thus causing an elevation in central blood pressure (CBP). The present study was designed to examine whether smoking cessation treatment improved CBP and arterial stiffness.

PATIENTS AND METHODS

We conducted an observational study of 70 patients receiving smoking cessation treatment. Before and 60 weeks after the start of a 12-week varenicline treatment, we measured brachial blood pressure, CBP, brachial-ankle pulse wave velocity (baPWV), normalized radial augmentation index (rAIx@75), left ventricular weight, and left ventricular diastolic function of each patient. The data were compared between the patients who succeeded in quitting smoking (smoking cessation group; n = 37) and those who failed to quit smoking (smoking group; n = 33).

RESULTS

Baseline characteristics were similar in both groups. Brachial blood pressure remained unchanged in both groups. CBP, baPWV, and rAIx@75 decreased significantly in the smoking cessation group, while these parameters showed no significant change in the smoking group. Thus, CBP, baPWV, and rAIx@75 showed greater decrease in the smoking cessation group than in the smoking group (CBP, -7.1 ± 1.4 mmHg vs 1.2 ± 2.7 mmHg; P < 0.01; baPWV, -204 ± 64 cm/s vs -43 ± 72 cm/s; P < 0.01; rAIx@75, -6.4 ± 2.8% vs -1.0 ± 3.9%; P < 0.01). Left ventricular weight and left ventricular diastolic function remained unchanged in both groups.

CONCLUSION

Patients in the smoking cessation group showed significant improvement in CBP, baPWV, and rAIx@75. These results indicate that smoking cessation can improve arterial stiffness and CBP.

Early Identification of Vascular Damage in Patients With Systemic Sclerosis

Vascular involvement in systemic sclerosis (SSc) plays a key role in the pathogenesis of fibrosis. We assessed arterial stiffness using a new echo-tracking technique in patients with SSc asymptomatic for cardiovascular diseases. We enrolled 22 patients (21 female, 63 ± 14 years) and 20 controls (12 female, 62 ± 3 years). Carotid intima-media thickness (IMT) was comparable between the 2 groups (1.1 ± 0.3 vs 1.0 ± 0.4 mm, P = ns), whereas the stiffness parameters were significantly increased in patients (β: 9.5 ± 4.2 vs 5.8 ± 1.1, P = .001; pulse wave velocity [PWV]: 6.5 ± 1.5 vs 5.2 ± 0.6 m/sec, P = .003). A correlation between stiffness parameters, anti-Scl-70 antibodies (β: r = .46, P = .03; PWV: r = .50, P = .02), and anticentromere antibodies (β: r = -.54, P = .020; PWV: r = -.53, P = .023) was found. Echo-tracking technique may be valuable in early identification of vascular involvement in patients with SSc.

Obstructive sleep apnea and aging effects on macrovascular and microcirculatory function

STUDY OBJECTIVES

Many patients with obstructive sleep apnea (OSA) are obese, and whether obesity itself explains the increased prevalence of cardiovascular disease in OSA is unknown. We hypothesize that OSA, independent of obesity, contributes to abnormal vascular function.

DESIGN

Physiology study.

SETTING

Academic medical centers.

PATIENTS

Obese subjects, free of known comorbidities, were enrolled.

MEASUREMENTS AND RESULTS

Vascular function was assessed with brachial artery ultrasound for flow-mediated dilation (FMD) and in skin microcirculation by laser Doppler flowmetry. Arterial stiffness was measured by arterial tonometry. Seventy-two subjects (43/72 women, 38/72 with OSA) were studied. FMD was impaired in patients with OSA, compared with control subjects (5.7% +/- 3.8% vs 8.3% +/- 4.1%, P = 0.005). In step-forward regression analysis inclusive of age, sex, and body mass index, age (P = 0.013) was a significant independent predictor of FMD. In a subgroup of subjects younger than 50 years of age (n = 59), however, OSA was the only independent predictor of FMD (P = 0.04), adjusted for known covariates. OSA did not significantly influence vascular function in the skin microcirculation. The augmentation index, a measure of arterial stiffness, was similar between the OSA and control groups (16.2% +/- 11.4% vs 20.4% +/- 10.1%, respectively, P = 0.10). In step-forward regression analysis of younger men (< or = 50 years old, 23 subjects), OSA independently predicted the augmentation index in men only (P = 0.001).

CONCLUSIONS

In obesity, both OSA and aging impair endothelial function and increase arterial stiffness. The influence of OSA on vascular function is most pronounced in young subjects. OSA, therefore, may be associated with functional impairment ("a premature aging effect") on the endothelium and on arterial stiffness (in men), although skin microcirculatory function appears preserved.