Increased pulse wave velocity and augmentation index after isometric handgrip exercise in patients with coronary artery disease

Longitudinal profiling and tracking stability in the Singapore study of macro-angiopathy and microvascular reactivity in type 2 diabetes cohort

INTRODUCTION

The Singapore Study of Macro-Angiopathy and microvascular Reactivity in Type 2 Diabetes (SMART2D) is a prospective cohort study which was started in 2011 to investigate the effect of risk factors on vascular function and diabetes-related complications in Asians. We aimed to compare the longitudinal change in risk factors by accounting for batch effect and assess the tracking stability of risk factors over time in patients recruited for SMART2D. In this study, we (1) described batch effect and its extent across a heterogenous range of longitudinal data parameters; (2) mitigated batch effect through statistical approach; and (3) assessed the tracking stability of the risk factors over time.

METHODS

A total of 2258 patients with type 2 diabetes mellitus (T2DM) were recruited at baseline. The study adopted a three-wave longitudinal design with intervals of 3 years between consecutive waves. The changes in a few selected risk factors were assessed after calibration, assuming patients with similar demographic and anthropometry profile had similar physiology. The tracking pattern of the risk factors was determined with stability coefficients derived from generalised estimating equations.

RESULTS

The medians of the longitudinal differences in risk factors between the waves were mostly modest at <10%. Larger increases in augmentation index (AI), aortic systolic blood pressure (BP) and aortic mean BP were consistently observed after calibration. The medians of the longitudinal differences in AI, aortic systolic BP and aortic mean BP between the waves were <2% before calibration, but increased slightly to <5% after calibration. Most of the risk factors had moderate to high tracking stability. Muscle mass and serum creatinine were among those with relatively high tracking stability.

CONCLUSIONS

The longitudinal differences in parameters between the waves were overall modest after calibration, suggesting that calibration may attenuate longitudinal differences inflated by non-biological factors such as systematic drift due to batch effect. Changes of the hemodynamic parameters are robust over time and not entirely attributable to age. Our study also demonstrated moderate to high tracking stability for most of the parameters.

Local arterial stiffness measured by ultrafast ultrasound imaging in childhood cancer survivors treated with anthracyclines

Background

There is conflicting literature regarding the long-term effect of anthracycline treatment on arterial stiffness. This study assessed local arterial stiffness using ultrafast ultrasound imaging (UUI) in anthracycline treated childhood cancer survivors, at rest and during exercise.

Methods

20 childhood cancer survivors (mean age 21.02 ± 9.45 years) treated with anthracyclines (mean cumulative dose 200.7 ± 126.80 mg/m²) and 21 healthy controls (mean age 26.00 ± 8.91 years) were included. Participants completed a demographic survey, fasting bloodwork for cardiovascular biomarkers, and performed a submaximal exercise test on a semi-supine bicycle. Pulse wave velocity (PWV) was measured in the left common carotid artery by direct pulse wave imaging using UUI at rest and submaximal exercise. Both PWV at the systolic foot (PWV-SF) and dicrotic notch (PWV-DN) were measured. Central (carotid-femoral) PWV was obtained by applanation tonometry. Carotid measurements were taken by conventional ultrasound. Measures were compared using two-tailed Students t-test or Chi-squared test, as appropriate.

Results

There was no statistically significant difference (p > 0.05) between childhood cancer survivors and healthy controls in demographic parameters (age, sex, weight, height, BMI), blood biomarkers (total cholesterol, triglycerides, LDL-c, HDL-c, hs-CRP, fasting glucose, insulin, Hb A1c), cardiovascular parameters (intima media thickness, systolic and diastolic blood pressure, heart rate, carotid diameters, distensibility) or PWV measured by UUI at rest or at exercise. There was also no difference in the cardiovascular adaptation between rest and exercise in the two groups (p > 0.05). Multivariate analysis revealed age (p = 0.024) and LDL-c (p = 0.019) to be significant correlates of PWV-SF in childhood cancer survivors, in line with previously published data.

Conclusion

We did not identify a significant impact of anthracycline treatment in young survivors of childhood cancer on local arterial stiffness in the left common carotid artery as measured by UUI.

Impact of acute and chronic regular exercise on arterial stiffness and reflection measures in coronary artery disease patients: A Protocol for Randomized Clinical Trial

Vascular stiffness due to arteriosclerosis reduces arterial elasticity which is as an independent and non-invasive predictor of future incidence of coronary heart disease and stroke. There is limited evidence of the benefits of regular exercise on arterial stiffness in populations suffering from cardiovascular diseases (CVD) especially coronary artery disease (CAD).

Aim. To determine the acute and chronic effects of aerobic, resistance and combined exercise on arterial and hemodynamic function in patients with CAD.

Material and methods. This study will be a prospective, single-blind, randomized study examining the effects of exercise on arterial stiffness. The study will be conducted at a tertiary care hospital for a continuous period of one year. Patients with CAD (n=105) will be selected using systematic sampling techniques and allocated randomly to one of the four treatment groups using computer-generated, random number sequence for age, sex and health status of CAD (Group-I: aerobic exercise, Group-II: resistance exercise, Group-III: combined aerobic and resistance exercise, and Group-IV: control) as per the inclusion and exclusion criteria. All recruited subjects will be informed about the assessment and intervention procedure before getting the consent form filled. This project followed the guidelines of standard protocol for randomized clinical trials (spirit).

Perspective. It is expected that this study protocol shall through light and be helpful in better quality of life along with decline in drug dependency for the people suffering from CAD. Further this study will be valuable is designing exercise protocol for the people suffering from CAD.

Association of changes of pulse wave velocity and augmentation index after isometric handgrip exercise with coronary lesion extent and revascularization

Background

Arterial stiffness is associated with myocardial ischemia and incident coronary artery disease (CAD), and indexes of arterial stiffness are usually increased in patients with CAD. However, these indexes are often increased in elderly without CAD. Arterial stiffness in patients with CAD may become more evident after isometric handgrip exercise which increases systolic pressure and ventricular afterload. We investigated the association of the change of stiffness indexes after isometric handgrip exercise with the lesion extent of CAD and the necessity for coronary revascularization.

Methods

Patients who were scheduled a routine coronary angiography via a femoral artery were enrolled. Arterial waveforms were traced at aortic root and external iliac artery using coronary catheters at baseline and 3 min after handgrip exercise. Augmentation index (AIx) was measured on the recorded aortic pressure waveform, and pulse wave velocity (PWV) was calculated using the ECG-gated time difference of the upstroke of arterial waveforms and distance between aortic root and external iliac artery.

Results

Total 37 patients were evaluated. Both PWV and AIx increased after handgrip exercise. ΔPWV was significantly correlated with ΔAIx (r = 0.344, P = 0.037). Patients were divided into higher and lower ΔPWV or ΔAIx groups based on the median values of 0.4 m/sec and 3.3%, respectively. Patients with higher PWV had more 2- or 3-vessel CAD (69% vs. 27%, P = 0.034), and underwent percutaneous coronary intervention (PCI) more frequently (84% vs. 50%, P = 0.038), but higher ΔAIx was not associated with either the lesion extent or PCI. Area under curve (AUC) of ΔPWV in association with PCI by C-statistics was 0.70 (95% confidence interval [CI] 0.51–0.88; P = 0.056). In multiple logistic regression analysis, ΔPWV was significantly associated with PCI (odds ratio 7.78; 95% CI 1.26–48.02; P = 0.027).

Conclusions

Higher ΔPWV after isometric handgrip exercise was associated with the lesion extent of CAD and the necessity for coronary revascularization, but higher ΔAIx was not.

Aerobic exercise, but not isometric handgrip exercise, improves endothelial function and arterial stiffness in patients with myocardial infarction undergoing coronary intervention: a randomized pilot study

Background

Aerobic exercise improves endothelial function and arterial stiffness after myocardial infarction (MI), but the effects of isometric exercise on cardiovascular parameters are still uncertain. We aimed to assess the effects of one session of aerobic or isometric exercise on flow-mediated dilation (FMD) and pulse wave velocity (PWV) in post-MI volunteers undergoing percutaneous coronary intervention (PCI).

Methods

Twenty post-MI patients undergoing PCI were randomized to aerobic (AE, n = 10) or isometric (IE, n = 10) exercise groups. We evaluated cardiac structure and function (echocardiographic); carotid plaque presence (ultrasound). FMD and PWV were measured 10 min before and 10 min after the intervention: a single session of moderate-intensity AE (30 min; ratings 12–14 on Borg’s scale or 50–60% HRreserve) or handgrip IE (four two-minute bilateral contractions; 30% maximal voluntary contraction; 1-min rest). Generalized estimating equations (Bonferroni post-hoc) was used to assess differences (p ≤ 0.050).

Results

FMD improved only in the AE group (Δ = 4.9%; p = 0.034), with no difference between groups after exercise. Even after adjustment (for baseline brachial artery diameter) the effectiveness of AE remained (p = 0.025) with no change in the IE group. PWV was slightly reduced from baseline in the AE group (Δ = 0.61 m/s; p = 0.044), and no difference when compared to the IE group. Peripheral vascular resistance decreased in AE versus IE (p = 0.050) and from baseline (p = 0.014).

Conclusions

Vascular measurements (FMD and PWV) improved after a single session of AE. There are apparently no benefits following a session of IE.

Trial registration

http://www.clinicaltrials.gov and ID number NCT04000893.

Cardiovascular responses to low-intensity isometric handgrip exercise in coronary artery disease: effects of posture

BACKGROUND

Coronary artery disease (CAD) lead to cardiovascular autonomic control disfunctions that can worsen exercise and/or posture adjustments.

OBJECTIVES

To verify the cardiovascular responses to low-intensity isometric handgrip exercise performed in different postures in CAD patients. This study tested the hypothesis that the posture influences the cardiovascular responses during isometric handgrip exercise and that the presence of CAD leads to greater cardiovascular stress during this type of exercise.

METHODS

We investigated cardiovascular responses to isometric handgrip exercise in 15 CAD patients (CADG) and 15 health matched-control (CG). The subjects performed isometric handgrip exercise at 30% of maximum voluntary contraction until exhaustion in SUPINE, SITTING and STANDING positions. Systolic arterial pressure, diastolic arterial pressure, mean blood pressure, heart rate, peripheral vascular resistance, cardiac output, stroke volume and double product were measured during rest (baseline), exercise (peak value) and recovery in the 1st minute (REC1). Delta PB (ΔPB, peak minus baseline) and PR1 (ΔPR1, peak minus REC1) were calculated.

RESULTS

Higher ΔPB and ΔPR1 of systolic and mean arterial pressure and double product were observed in STANDING when compared to SITTING and/or SUPINE. CADG showed higher ΔPB of systolic and mean arterial pressure in all postures and higher ΔPR1 of strove volume in the SITTING.

CONCLUSION

We concluded that the posture during isometric handgrip exercise influences the cardiovascular responses with STANDING leading to higher cardiovascular stress. CAD promoted higher arterial pressure responses however these responses were physiological and expected due to the presence of disease and type of exercise.

Arterial Stiffness Can Be Modulated by Pressure-Independent Mechanisms in Hypertension

Background Effects of short-term interventions on large-artery stiffness assessed by pulse wave velocity (PWV) have mainly been explained by concomitant changes in blood pressure (BP). However, lower body negative pressure, which increases sympathetic activity and has other hemodynamic effects, has a specific effect on PWV in healthy volunteers. Methods and Results We examined effects of lower-limb venous occlusion (LVO), a similar intervention to lower-body negative pressure that reduces BP but increases sympathetic activity and device-guided breathing (DGB), which reduces both BP and sympathetic activity, on PWV in patients with essential hypertension (n=70 after LVO, n=45 after DGB and LVO in random order). The short-acting calcium channel antagonist nifedipine was used as a control for changes in BP. LVO produced a small but significant reduction in mean arterial pressure of 1.8 (95% CI 0.3-3.4) mm Hg. Despite this, aortic and carotid-femoral PWV increased during LVO by 0.8 (0.2-1.4) m/s and 0.7 (0.3-1.05) m/s, respectively. DGB reduced PWV by 1.2 (0.9-1.4) m/s, to a greater extent than did nifedipine 10 mg (reduction of 0.7 [0.1-1.3] m/s, P<0.05 compared with reduction during DGB). This occurred despite a greater decrease in BP with nifedipine compared with DGB. Conclusions Arterial stiffness can be modulated independently of BP over the short term. The mechanism could involve alterations in sympathetic activity or other as yet uncharacterized effects of LVO and DGB.

Resting and exercise arterial dysfunction in anthracycline-treated adult survivors of childhood cancers

BACKGROUND

Emerging evidence suggests potential arterial damage with the use of anthracycline-based chemotherapeutic regimens. We determined arterial function at rest and during exercise in anthracycline-treated adult survivors of childhood cancers.

METHODS

Ninety-six adult survivors (54 males) aged 25.0 ± 5.9 years and 60 (30 males) healthy controls were studied. Central systolic blood pressure (cSBP) and radial augmentation index (rAI) was determined by applanation tonometry. Carotid arterial stiffness and intima-media thickness (IMT) were assessed using high-resolution ultrasound.

RESULTS

At rest, survivors had significantly greater carotid IMT (p < 0.001) and stiffness index (p < 0.001), and higher cSBP (p = 0.037), rAI (p = 0.004) and rAI adjusted for a heart rate of 75/min (p = 0.009) than controls. At submaximal supine exercise testing, survivors had significantly greater percentage increase in carotid stiffness than controls (p < 0.001). Among survivors, 32 and 53% had respectively carotid IMT and exercise stiffness index exceeding normal (> + 2SD of controls). The slopes of increase in carotid IMT (p < 0.001) and exercise-induced changes in carotid stiffness (p < 0.001) with age were significantly greater in survivors than controls. Multivariate analysis revealed carotid IMT (β = 0.32, p < 0.001) to be an significant correlate of dynamic percentage increase in stiffness index during exercise.

CONCLUSIONS

Arterial dysfunction is evident at rest and worsens during exercise in anthracycline-treated adult survivors of childhood cancers.

Reliability of arterial stiffness indices at rest and following a single bout of moderate-intensity exercise in older adults

Short-term changes in arterial stiffness with exercise are proposed to better reflect vascular impairments than resting measures alone and are suggested as a prognostic indicator of cardiovascular risk in older adults. Arterial stiffness indices are reliable at rest, but the time-course and reliability of postexercise changes in arterial stiffness in older adults are unknown. The precision of postexercise changes in arterial stiffness should be determined prior to their use in large prospective trials. This study assessed the between-day reliability of the changes in pulse wave velocity (PWV), augmentation index (AIx75) and reflection magnitude (RM) following an exercise bout in older adults. Ten older adults (71 ± 5 years) were tested on three separate days, 7 days apart. PWV, AIx75 and RM were assessed at rest, immediately post and at 20, 40 and 60 min during recovery after moderate-intensity cycling. Intraclass correlation coefficient (ICC) and reliability coefficient (RC) were used to assess the relative and absolute reliability of arterial stiffness responses. PWV increased, and RM decreased immediately after exercise (P<0·05), and returned to baseline during recovery. AIx decreased during recovery (P<0·001). Resting ICC values were 0·91 (PWV), 0·72 (AIx75) and 0·40 (RM). Reliability of the immediate changes following exercise was high for PWV (ICC:0·87, RC:1·9 m s^-1 ) and moderate for AIx75 (ICC:0·64, RC:7%) and RM (ICC:0·59, RC:9%). Reliability of the postexercise responses was similar to that at rest for all measures of arterial stiffness. These findings indicate that postexercise changes in arterial stiffness indices are reliable in healthy older adults and supports further investigation of the prognostic value of these responses.

Micro-patterned graphene-based sensing skins for human physiological monitoring

Ultrathin, flexible, conformal, and skin-like electronic transducers are emerging as promising candidates for noninvasive and nonintrusive human health monitoring. In this work, a wearable sensing membrane is developed by patterning a graphene-based solution onto ultrathin medical tape, which can then be attached to the skin for monitoring human physiological parameters and physical activity. Here, the sensor is validated for monitoring finger bending/movements and for recognizing hand motion patterns, thereby demonstrating its future potential for evaluating athletic performance, physical therapy, and designing next-generation human-machine interfaces. Furthermore, this study also quantifies the sensor's ability to monitor eye blinking and radial pulse in real-time, which can find broader applications for the healthcare sector. Overall, the printed graphene-based sensing skin is highly conformable, flexible, lightweight, nonintrusive, mechanically robust, and is characterized by high strain sensitivity.

The Role of the Autonomic Nervous System in the Regulation of Aortic Stiffness

The autonomic nervous system is important in regulating blood pressure, but whether it regulates aortic stiffness is more contentious. We conducted 3 studies in young, healthy individuals to address this important question. Study 1 was a cross-sectional study of 347 subjects with detailed measurements of hemodynamics and heart rate variability. In study 2, 9 subjects were given a bolus of intravenous nicotinic ganglion blocker, pentolinium, or saline in a random order and hemodynamics and heart rate variability were assessed before and after. In study 3, changes in hemodynamics and heart rate variability were assessed during stimulation of the sympathetic nervous system with the use of isometric handgrip exercise in 12 subjects. Study 1: aortic pulse wave velocity (P=0.003) was lowest in the subjects with the highest parasympathetic activity, but after adjusting for mean arterial pressure, the effect was abolished (P=0.3). Study 2: after pentolinium, sympathetic and parasympathetic activity fell (P=0.001 for both), mean arterial pressure, and heart rate increased (P=0.004 and P=0.04, respectively), but there was no change in pulse wave velocity in comparison to placebo (P=0.1). Study 3: during handgrip exercise, sympathetic activity (P=0.003), mean arterial pressure (P<0.0001), and aortic pulse wave velocity increased (P=0.013). However, pulse wave velocity adjusted for mean arterial pressure did not change (P=0.1). The main finding of these studies is that in young healthy subjects, the autonomic nervous system does not have a pressure-independent role in the regulation of aortic stiffness. However, these findings may not apply to patients with increased sympathetic tone or hypertension.