Cardiac autonomic associations on exercise and ambulatory capacity in individuals with lower-extremity artery disease

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): This work was in part supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP #2019/19596-7), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq #303399/2018-0).

OnBehalf

Exercise and Chronic Disease Research Laboratory - Bauru, Brazil; Research Group for Cardiovascular Rehabilitation - Leuven, Belgium.

INTRODUCTION

Lower-extremity artery disease (LEAD) characterized by progressive atherosclerotic build-up in leg arteries is becoming increasingly prevalent, affecting more than 200 million people worldwide. In line with other atherosclerotic disorders, LEAD is often associated with autonomic dysfunction as evidenced by a reduced heart rate variability (HRV). To date, little is known on the impact of cardiac autonomic function on exercise and ambulatory capacity.

PURPOSE

We aimed to investigate whether autonomic function is associated with ambulatory capacity and exercise capacity in patients with LEAD.

METHODS

Thirty-four patients (age≥17 years) diagnosed with LEAD (ankle brachial index: ABI ≤ 0.9 and/or 20% decrease after a maximal treadmill test) suffering from intermittent claudication (Rutherford I-III) were recruited in the PROSECO-IC trial. Patients were grouped based on beta-blocker medication (β-blocker and non β-blocker). Intervals between R waves (i-RR) obtained by heart rate (HR) signal were acquired beat-to-beat via a digital telemetry system (Polar®️ H10) during 15 min of supine rest and were used for 5-minute HRV analysis. Time domain indexes (mean i-RR, SNDD, pNN50%), and frequency domains (high frequency band (HF), low frequency (LF, very LF (VLF)) and the ratio (LF/HF). HRV was analyzed in absolute (abs), normalized (nu) and log units (log). Ambulatory capacity was assessed by means of a submaximal treadmill test, graded maximal treadmill test using Gardner protocol (GTM) and 6 minutes walking test (6MWT); exercise capacity was assessed by means of a graded maximal cardiopulmonary exercise test (HR, blood pressure (BP) and peak oxygen uptake (VO2peak)) at resting, 2 minutes, and peak of exercise.

RESULTS

Pearson test showed that sympathetic modulation indexes were moderate associated with pain free distance in GTM (LF/HF: r = 0.52, p = 0.04), and pain free time in 6MWT (LFlog: r=-0.62, p = 0.01; VLF: r=-0.52, p = 0.04), respectively, in patients without β-blocker. Similar HR associations with HRV (time and frequency domain) were observed during submaximal treadmill test and cardiopulmonary exercise test (p ≤ 0.05). Test-t demonstrated a significantly increased response intra-groups in HR and BP during both tests (p ≤ 0.05). Average BP were positive associated with the earlier stages of the cardiopulmonary test (resting to 2 min) with LFlog (r = 0.70, p= <0.001) in β-blocker while non-β-blocker were associated from 2 min to peak with LFabs (r = 0.67, p= <0.001) and LF/HF (r = 0.52, p = 0.03). 

CONCLUSION

Sympathetic modulation was correlated with a longer pain free walking capacity in non-β-blockers. Yet, individuals treated by -β-blockers showed an earlier sympathetic modulation through exercise pressor response during the first stages of cardiopulmonary exercise compared to non-β-blockers with LEAD.

The use of Near-Infrared Spectroscopy to evaluate the effect of exercise on peripheral muscle oxygenation in patients with lower-extremity artery disease: a systematic review

Funding Acknowledgements

Type of funding sources: None.

Background

Near-Infrared Spectroscopy (NIRS) has been suggested as a new diagnostic tool in patients with lower-extremity artery disease (LEAD). The aim of this systematic review was i) to summarize the impact of exercise therapy on lower-limb muscle oxygenation, evaluated by means of NIRS, in patients with LEAD and ii) to give an overview on NIRS instruments and methodology.

Methods

A systematic search was conducted in MEDLINE and Embase, from the earliest date available until 16th of March 2020, to identify peer-reviewed studies involving the use of NIRS in the evaluation of exercise training on muscle oxygenation in patients with LEAD. Primary outcomes were NIRS-derived variables. Effect sizes were calculated as standardized mean differences. Assessment of methodological quality was done using a combined checklist from the Cochrane bias and the quality assessment tool for before-after studies without control group.

Results

Eleven original trials were included involving 16 exercise groups and 4 control groups. Tissue saturation index (TSI) at rest remained unchanged following the exercise interventions. Yet, exercise training increased time-to-minimum TSI during exercise (range effect sizes: +0.172 to +0.927). In addition, exercise training led to a faster recovery to half and full TSI rest values in most intervention groups (range effect sizes: -0.046 to -0.558 and -0.269 to -0.665 respectively). Finally, NIRS data reproducibility and analytic methods were underreported in the included studies. To illustrate, only four studies reported appropriate measures to ensure repeated reproducible probe positioning. The use of raw or filtered data for analysis was reported in none of the included articles.

Conclusion

The available NIRS data suggest that exercise training improves deoxygenation and reoxygenation patterns in patients with LEAD. Whereas NIRS is a promising tool in the evaluation of LEAD, the low number of RCT’s as well as large heterogeneity in NIRS assessment methods, outcome measures and instrumentation, warrants more research to better understand the role of muscle oxygenation associated with exercise-induced improvements in walking capacity. In particular the role of NIRS to study underlying mechanisms and determinants related to exercise progression in LEAD patients is appealing.

Abstract Figure. NIRS during treadmill test

Is a single bout of exercise also a viable tool for blood pressure management in African and Asian populations? The HYPE2X trial protocol and design

Funding Acknowledgements

Type of funding sources: None.

Introduction

Current national and international guidelines recommend exercise as the first line treatment (class IA recommendation) for hypertension. These guidelines are based on research performed in predominantly Caucasian populations, yet the potency of exercise for lowering blood pressure (BP) is less studied in non-Caucasian populations. It is well-known that a great variability exists in the response to pharmacological antihypertensive treatments among ethnic groups. However, it is not clear whether this variability is also present regarding the BP response to exercise.  The ‘Hypertension, Ethnicity and Exercise’ (HYPE²X ) trial will i) investigate whether a short bout of isometric strength or endurance exercise lowers blood pressure in African and Asian populations; ii) evaluate and compare differences in acute response to exercise between the Africans and Asians, and iii) increase our understanding on mechanisms related to blood pressure responses to exercise in these non-Caucasian populations.

Methods and analyses

A randomized controlled crossover trial will be conducted in 60 adults of African (n = 30; 50% female) or Asian (n = 30, 50% female) origin, ≥ 18 years. Healthy individuals with high to normal blood pressure (SBP: 130 – 139 mmHg or and DBP: 85 – 89 mmHg) or grade I hypertension (grade 1, SBP: 140 – 159 mmHg or DBP: 90 – 99 mmHg) will be recruited at outpatient clinics in Suriname between November 2020 – February 2021. Patients will complete three experimental sessions in a randomized order: a 30 minute walking/running bout at 40-60% of heart rate reserve; an isometric handgrip session at 30% of maximal handgrip strength and a sitting control session. (See Figure 1). Measurements will be performed before and immediately after each session. The primary outcome is daytime blood pressure measured by means of 24h blood pressure monitoring.  Secondary outcomes include office BP, autonomic function (heart rate variability), cardiac function (left ventricle function), vascular function (pulse wave velocity and flow-mediated dilation) and the renin-angiotensin aldosterone system (plasma renin and aldosterone levels). Analyses will be performed using mixed models for repeated measures. A two-tailed p-value <0.05 will be considered statistically significant.

Conclusion

It is anticipated that the HYPE²X trial will contribute to a better understanding of the response of non-Caucasians to lifestyle interventions, in particular exercise therapy.

Abstract Figure 1. Flowchart of the RCOT

The effects of exercise training on muscle oxygenation of patients with intermittent claudication

Funding Acknowledgements

Type of funding sources: None.

Background. Intermittent claudication (IC) is characterized by a cramp-like pain during walking caused by insufficient blood flow to the lower limbs during exercise. The walking impairment caused by IC can lead to a vicious cycle of physical inactivity, decreased quality of life and progression of cardiovascular risk factors. Although current evidence supports the benefits of walking training to increase walking capacity, little is known about its effect on muscle oxygenation in this population. Purpose. The aim of this study was to investigate the effects of a hybrid 12-week walking program (combined center- and home-based walking) on muscle oxygenation of IC patients. Methods. Thirty-seven patients with IC were enrolled of which 33 completed follow-up measurements (age 71 ± 9 yrs, body mass index 26 ± 4 kg/m2, ankle brachial index (ABI) 0.7 ± 0.2) after the 12-week intervention. Outcome measures were pain-free walking capacity (PFWC), maximal walking capacity (MWC) and calf muscle oxygenation, respectively evaluated using a submaximal treadmill test, a Gardner treadmill test and near-infrared spectroscopy (NIRS). Results. After the 12-week intervention, significantly higher values (reported as median and interquartiles) for PFWC (162 m [122, 217] to 272 m [150, 401]; p < 0.001) and MWC (458 m [260, 638] to 611 m [333, 840]; p < 0.001) were observed. As shown in Table 1, NIRS data measured during the submaximal walking test showed an increased availability of oxygenated hemoglobin (p = 0.048) and decreased deoxyhemoglobin (p = 0.013), while total hemoglobin remained unchanged after the 12-week intervention. During the Gardner test, time to reach minimum tissue saturation index (TSI%) increased (p < 0.001), yet no change was noted on minimum TSI during exercise, despite increased MWC. Despite a trend towards faster recovery times, no significant changes were observed after the 12-week intervention. Conclusion. Hybrid walking exercise therapy improves deoxygenation kinetics and walking capacity in IC patients. Increased availability of oxygenated hemoglobin might underly the improvement in walking capacity.

The impact of health apps on lifestyle behaviours and cardiovascular risk factors in patients with cardiovascular risk factors or established cardiovascular disease: a systematic review

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme

Background

 Adequate levels of physical activity (PA) and a healthy diet can contribute to weight loss, improved blood pressure, improved lipid levels and higher insulin sensitivity and thus decrease the risk for the development of cardiovascular disease (CVD). Recently, mobile technologies, such as mobile applications (apps) have been developed for supporting adherence to a healthy lifestyle in an individualized and interactive manner. 

Purpose

 The aim of this systematic review was to summarize the effectiveness of such mobile apps targeting PA and/or dietary behavior and cardiovascular risk factors in primary and secondary prevention. 

Methods

Four databases (Pubmed, Sportdiscus, Cinahl, Embase) were searched to identify prospective studies evaluating mobile apps targeting healthy diet and/or PA. Rayyan software was used for screening articles. Only interventional trials that assessed the effectiveness of health apps on diet, PA and/or cardiovascular risk factors were included. Quality assessment was performed using the MINORS tool. Qualitative synthesis was performed providing data summaries according to different subgroups: healthy adults, adults who are overweight, have obesity, hypertension, CVD or diabetes. 

Results

Out of 7073 records identified, 52 articles, reporting on 44 studies with variable study designs, could be included in qualitative synthesis. Interventions targeted diet, PA and/or adherence to therapy/healthy lifestyle and reported on at least one cardiovascular risk factor. In 20 studies, weight loss was a target of the mobile intervention, the vast majority (17/20 studies) reported weight loss following app usage of at least similar extent as usual care. Twenty-six mobile interventions targeted PA and/or exercise training and 23 of them resulted in an increase in PA in the short term. Four studies performed in patients with CVD showed that health app usage could be related to increased PA and improved diet, resulting in similar health benefits as usual care. The most commonly employed behavioural change methods were goal setting and self-monitoring, the use of financial incentives for inducing beneficial lifestyle changes yielded inconclusive results. Main limitations of the studies were small sample sizes, short follow-up duration and lack of controlled trial design. 

Conclusion

Mobile apps targeting healthy lifestyle for the management of cardiovascular risk factors seem to be valuable tools to add to current practice in preventive medicine. However, larger, controlled studies with longer follow-up duration are needed to confirm these early findings.

The experiences and perceptions of nursing service managers regarding transformation of health services in selected provincial academic health complexes

Nursing service managers are challenged with enormous transformations within the new political dispensation in South Africa. The objective of the study was to explore and describe the experiences and perceptions of the nursing service managers regarding transformation of health services in selected Provincial Academic Health Complexes. A qualitative, exploratory, descriptive and phenomenological design was employed utilising focus group interviews and narratives as methods of data collection. After content analysis was performed, results were grouped into management of health service transformation and quality of patient care in relation to the levels of the organisation. The levels in the organisation are individual level, group level, departmental level and organisational level. Positive and negative experiences and perceptions were identified.

Effect of moderate dietary protein restriction on the progression of overt diabetic nephropathy: a 6-mo prospective study

To assess whether moderate dietary protein restriction can delay the progression of overt diabetic nephropathy, 22 subjects with insulin-dependent diabetes mellitus were randomly assigned to an unrestricted protein diet (> 1.6 g.kg body wt-1.d-1) or a moderately protein-restricted diet (0.8 g.kg body wt-1.d-1) and followed prospectively for six mo. Direct isotope methods were used to assess renal function. Protein intake was assessed by measurement of urinary urea nitrogen. The two groups were well-matched for age, sex, duration of diabetes, glycemic control, blood pressure, and degree of renal insufficiency. Patients consuming the unrestricted protein diet (n = 11) showed a progressive decline in glomerular filtration rate of 1.3 mL.min-1.mo-1 with no change in proteinuria. Patients consuming the moderately protein-restricted diet showed a marked decrease in the degree of proteinuria (2.15-1.13 g/d, P = 0.036) and a stabilization of glomerular filtration rate. This occurred independently of changes in blood pressure or glycemic control. Moderate dietary protein restriction can ameliorate progression of overt diabetic nephropathy.

Simultaneous ocular and orbital involvement from metastatic bronchogenic carcinoma

A 64-year-old man presented with a nonrhegmatogenous retinal detachment, proptosis, and ptosis. Clinical examination, fluorescein angiography, B-scan ultrasonography and computed tomographic (CT) scan confirmed the presence of concomitant intraocular tumor and orbital mass. The CT scan of the chest and a lung biopsy specimen revealed the presence of an unsuspected asymptomatic bronchogenic carcinoma that rapidly developed widespread metastases. Metastasis to the eye from bronchogenic carcinoma may occur simultaneously with orbital metastasis, and this may be associated with rapid progression and growth.