Exercise intolerance in pulmonary arterial hypertension

Reduced exercise capacity occurs before intrinsic skeletal muscle dysfunction in experimental rat models of pulmonary hypertension

Reduced exercise capacity in pulmonary hypertension (PH) significantly impacts quality of life. However, the cause of reduced exercise capacity in PH remains unclear. The objective of this study was to investigate whether intrinsic skeletal muscle changes are causative in reduced exercise capacity in PH using preclinical PH rat models with different PH severity. PH was induced in adult Sprague-Dawley (SD) or Fischer (CDF) rats with one dose of SU5416 (20 mg/kg) injection, followed by 3 weeks of hypoxia and additional 0-4 weeks of normoxia exposure. Control s rats were injected with vehicle and housed in normoxia. Echocardiography was performed to assess cardiac function. Exercise capacity was assessed by VO2 max. Skeletal muscle structural changes (atrophy, fiber type switching, and capillary density), mitochondrial function, isometric force, and fatigue profile were assessed. In SD rats, right ventricular systolic dysfunction is associated with reduced exercise capacity in PH rats at 7-week timepoint in comparison to control rats, while no changes were observed in skeletal muscle structure, mitochondrial function, isometric force, or fatigue profile. CDF rats at 4-week timepoint developed a more severe PH and, in addition to right ventricular dysfunction, the reduced exercise capacity in these rats is associated with skeletal muscle atrophy; however, mitochondrial function, isometric force, and fatigue profile in skeletal muscle remain unchanged. Our data suggest that cardiopulmonary impairments in PH are the primary cause of reduced exercise capacity, which occurs before intrinsic skeletal muscle dysfunction.

One-minute sit-to-stand test in patients with pulmonary arterial hypertension associated with congenital heart disease: A single-center prospective study

BACKGROUND

Patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) have reduced exercise capacity. Recently, the 1-minute sit-to-stand test (1MSTST), which measures the number of repetitions from sitting to standing position in 1 minute, has been proposed as an alternative test to the 6-minute walking test (6MWT). The aim of our study was to assess the safety and results of the 1MSTST in comparison to the 6MWT in patients with PAH-CHD.

METHODS

Consecutive adult patients with PAH-CHD underwent the 6MWT and the 1MSTST on the same day. The 6-minute walking distance in meters and the number of repetitions on the 1MSTST were measured. Heart rate, peripheral oxygen saturations, Borg dyspnea score, and lower limb fatigue were recorded before and immediately after testing. Correlations between both tests and clinical, laboratory, and imaging parameters were statistically analyzed.

RESULTS

The study included 40 patients (50% female, mean age 43 ± 15 years), of whom 29 (72%) had Eisenmenger syndrome and 14 (35%) had Down syndrome. The number of 1MSTST repetitions correlated significantly with 6MWT distance (r = 0.807, p = 0.000). There were no adverse events, and the 1MSTST results correlated with the WHO functional class. Heart rate increase and oxygen desaturation after both tests correlated significantly, but less desaturation was observed after 1MSTST.

CONCLUSIONS

Our study showed that the 1MSTST is a safe and easily applicable test in adult patients with PAH-CHD, including patients with Down syndrome. The results of the 1MSTST correlate significantly with the 6MWT, providing an alternative tool for exercise capacity assessment in patients with PAH-CHD.

Exercise Rehabilitation for People With End-Stage Kidney Disease: Who Will Fill the Gaps?

Exercise rehabilitation is a well established therapy for reducing morbidity and mortality and improving quality of life and function across chronic conditions. People with dialysis-dependent kidney failure have a high burden of comorbidity and symptoms, commonly characterised as fatigue, dyspnoea, and the inability to complete daily activities. Despite more than 30 years of exercise research in people with kidney disease and its established benefit in other chronic diseases, exercise programs are rare in kidney care and are not incorporated into routine management at any stage. In this review, we describe the mechanisms contributing to exercise intolerance in those with end-stage kidney disease and outline the role of exercise rehabilitation in addressing the major challenges to kidney care: cardiovascular disease, symptom burden, and physical frailty. We also draw on existing models of exercise rehabilitation from other chronic conditions to inform the way forward and challenge the status quo of exercise rehabilitation in both practice and research.

Efficacy of a Commercial Physical Activity Monitor in Longitudinal Tracking of Patients With Pulmonary Hypertension: A Pilot Study

BACKGROUND

Patients with pulmonary arterial hypertension have quality-of-life limitations, decreased exercise capacity, and poor prognosis if the condition is left untreated. Standard exercise testing is routinely performed to evaluate patients with pulmonary arterial hypertension but may be limited in its ability to monitor activity levels in daily living.

OBJECTIVE

To evaluate the validity of the commercial Fitbit Charge HR as a tool to assess real-time exercise capacity as compared with standard exercise testing.

METHODS

Ambulatory pediatric and adult patients were enrolled and given a Fitbit with instructions to continuously wear the device during waking hours. Patients underwent a 6-minute walk test, cardiopulmonary exercise test, and a 36-Item Short Form Health Survey on the day of enrollment and follow-up. Twenty-seven ambulatory patients with pulmonary arterial hypertension were enrolled, and 21 had sufficient data for analyses (median age, 25 years [range, 13-59 years]; 14 female participants).

RESULTS

Daily steps measured by the Fitbit had a positive correlation with 6-minute walk distance (r = 0.72, P = .03) and an inverse trend with World Health Organization functional class. On the 36-Item Short Form Health Survey, 77% of patients reported improvement in vitality (P = .055). At follow-up, there was a strong correlation between number of steps recorded by Fitbit and role limitations because of physical problems (r = 0.88, P = .02) and weaker correlations with other quality-of-life markers.

CONCLUSION

The findings of this pilot study suggest activity monitors may have potential as a simple and novel method of assessing longitudinal exercise capacity and activity levels in patients with pulmonary hypertension. Further study in larger cohorts of patients is warranted to determine which accelerometer measures correlate best with outcomes.

Exercise-based rehabilitation programmes for pulmonary hypertension

BACKGROUND

Individuals with pulmonary hypertension (PH) have reduced exercise capacity and quality of life. Despite initial concerns that exercise training may worsen symptoms in this group, several studies have reported improvements in functional capacity and well-being following exercise-based rehabilitation.

OBJECTIVES

To evaluate the benefits and harms of exercise-based rehabilitation for people with PH compared with usual care or no exercise-based rehabilitation.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 28 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people with PH comparing supervised exercise-based rehabilitation programmes with usual care or no exercise-based rehabilitation.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. exercise capacity, 2. serious adverse events during the intervention period and 3. health-related quality of life (HRQoL). Our secondary outcomes were 4. cardiopulmonary haemodynamics, 5. Functional Class, 6. clinical worsening during follow-up, 7. mortality and 8. changes in B-type natriuretic peptide. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included eight new studies in the current review, which now includes 14 RCTs. We extracted data from 11 studies. The studies had low- to moderate-certainty evidence with evidence downgraded due to inconsistencies in the data and performance bias. The total number of participants in meta-analyses comparing exercise-based rehabilitation to control groups was 462. The mean age of the participants in the 14 RCTs ranged from 35 to 68 years. Most participants were women and classified as Group I pulmonary arterial hypertension (PAH). Study durations ranged from 3 to 25 weeks. Exercise-based programmes included both inpatient- and outpatient-based rehabilitation that incorporated both upper and lower limb exercise. The mean six-minute walk distance following exercise-based rehabilitation was 48.52 metres higher than control (95% confidence interval (CI) 33.42 to 63.62; I² = 72%; 11 studies, 418 participants; low-certainty evidence), the mean peak oxygen uptake was 2.07 mL/kg/min higher than control (95% CI 1.57 to 2.57; I² = 67%; 7 studies, 314 participants; low-certainty evidence) and the mean peak power was 9.69 W higher than control (95% CI 5.52 to 13.85; I² = 71%; 5 studies, 226 participants; low-certainty evidence). Three studies reported five serious adverse events; however, exercise-based rehabilitation was not associated with an increased risk of serious adverse event (risk difference 0, 95% CI -0.03 to 0.03; I² = 0%; 11 studies, 439 participants; moderate-certainty evidence). The mean change in HRQoL for the 36-item Short Form (SF-36) Physical Component Score was 3.98 points higher (95% CI 1.89 to 6.07; I² = 38%; 5 studies, 187 participants; moderate-certainty evidence) and for the SF-36 Mental Component Score was 3.60 points higher (95% CI 1.21 to 5.98 points; I² = 0%; 5 RCTs, 186 participants; moderate-certainty evidence). There were similar effects in the subgroup analyses for participants with Group 1 PH versus studies of groups with mixed PH. Two studies reported mean reduction in mean pulmonary arterial pressure following exercise-based rehabilitation (mean reduction: 9.29 mmHg, 95% CI -12.96 to -5.61; I² = 0%; 2 studies, 133 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

In people with PH, supervised exercise-based rehabilitation may result in a large increase in exercise capacity. Changes in exercise capacity remain heterogeneous and cannot be explained by subgroup analysis. It is likely that exercise-based rehabilitation increases HRQoL and is probably not associated with an increased risk of a serious adverse events. Exercise training may result in a large reduction in mean pulmonary arterial pressure. Overall, we assessed the certainty of the evidence to be low for exercise capacity and mean pulmonary arterial pressure, and moderate for HRQoL and adverse events. Future RCTs are needed to inform the application of exercise-based rehabilitation across the spectrum of people with PH, including those with chronic thromboembolic PH, PH with left-sided heart disease and those with more severe disease.

Effectiveness of Respiratory Muscle Training in Adults With Pulmonary Hypertension. A Systematic Review and Meta-Analysis

BACKGROUND

Patients with pulmonary hypertension (PH) may have impaired exercise capacity and quality of life; this may possibly be due to the early onset of dyspnoea associated with respiratory muscle weakness. Respiratory muscle training could improve the condition of these patients, so this study aimed to determine, through a systematic review and meta-analysis, the effectiveness of respiratory muscle training in adult patients with PH.

METHODS

Medline, Embase, CENTRAL, clinical trial registries databases, and grey literature and reference lists of reviews related to the objective were searched up to March 2022. Controlled clinical trials comparing the effectiveness of respiratory muscle training with sham or no intervention in adults with PH were included. Records were independently screened by two authors. The primary outcomes were maximal and functional exercise capacity, quality of life, and dyspnoea. The secondary outcomes were respiratory muscle strength, physical activity, lung function, and adverse events. Two authors independently extracted data and the study quality was assessed using the Cochrane risk-of-bias tool 2 (RoB 2). The certainty of the evidence was assessed according to the GRADE approach.

RESULTS

A total of 5,524 records were screened, and seven randomised clinical trials (RCTs) (257 participants) were included. It was uncertain whether inspiratory muscle training (IMT), compared with sham IMT or no intervention, increased the distance walked in the 6-minute walk test (6MWT) (MD, 39 m; 95% CI, 20.72-57.39; I²=27%; four RCTs; very low certainty of evidence) and slightly decreased the perceived sensation of dyspnoea (MD, 0.5 points on the mMRC scale; 95% CI, -0.87 to -0.13; I²=0%; two RCTs; very low certainty of evidence). In addition, it was uncertain whether IMT had no effect on the emotional (SMD, -0.34; 95% CI, -1.06 to 0.38; I²=64%; three RCTs; very low certainty of evidence) and physical (SMD, 0.06; 95% CI, -0.41 to 0.52; I²=16%; three RCTs; very low certainty of evidence) component of quality of life.

CONCLUSIONS

It is uncertain whether IMT increases functional exercise capacity and slightly decreases the sensation of dyspnoea. In addition, it is uncertain whether IMT does not affect the quality of life. More RCTs and with a better methodological design are needed to increase the certainty of the evidence and determine the real effect of this intervention.

Exercise Capacity and Quality of Life in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease with a high mortality rate that can be divided into different groups according to etiology and prognosis. Few studies have investigated differences in the exercise capacity and quality of life (QOL) among the different groups of PAH patients. Therefore, we aimed to (1) compare the hemodynamic exercise responses between patients with idiopathic pulmonary arterial hypertension (IPAH) and PAH associated with other diseases (APAH), and (2) determine the factors associated with exercise capacity in patients with PAH.

METHODS

Six patients diagnosed with IPAH and eight with APAH [congenital heart disease (CHD)-dominant PAH] were included in this study. The main outcome measures included body composition, exercise capacity, hemodynamic measurements, physical activity levels, fatigue severity, and QOL.

RESULTS

The CHD-dominant PAH group had a significantly lower predicted peak oxygen consumption (VO2pred %), pressure of end-tidal carbon dioxide at the peak and at anaerobic threshold (PETCO2peak and PETCO2@AT), and significantly elevated ventilatory equivalent (VE/VCO2slope and VE/VCO2@AT) compared with the IPAH group. Multiple regression analysis indicated that PETCO2@AT was significantly associated with either VO2peak (β = 0.805, adjusted R2 = 0.619, p = 0.001) or 6-minute walk distance (β = 0.816, adjusted R2 = 0.638, p < 0.001).

CONCLUSIONS

Patients with CHD-dominant PAH had poor exercise capacity and exercise responses compared to those with IPAH. Evaluating exercise capacity and the patient response to exercise using cardiopulmonary exercise testing is increasingly important in view of the etiology of PAH.

Overview of Riociguat and Its Role in the Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH), which includes pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), is a progressive condition with significant morbidity and mortality due to right heart failure if left untreated. Riociguat is a soluble guanylate cyclase (sGC) stimulator and is the only treatment approved for both PAH and CTEPH. The objectives of this review are to describe the epidemiology and pathophysiology of PAH and CTEPH; synthesize the pharmacology, efficacy, safety, and utilization of riociguat; and discuss the role of the pharmacist in managing patients with these conditions. Data presented in this review is supported by peer reviewed literature, using PubMed and key words including pulmonary hypertension, pulmonary arterial hypertension, chronic thromboembolic pulmonary hypertension, and riociguat. The review draws on key studies and review articles that discuss the pathophysiology of PAH and CTEPH, as well as articles discussing the safety and efficacy of riociguat. The overall goal in the treatment of PAH and CTEPH is to improve long-term survival. Treatment planning depends on the type of PH, treatment goals, comorbidities, and risk profiles. Pharmacists serve a valuable role as part of the multidisciplinary team in the care of patients with PH, many of whom may have comorbidities that contribute to high costs and resource utilization. Riociguat is a first-in-class medication and the only approved treatment for both PAH and CTEPH. In clinical trials, riociguat has demonstrated favorable efficacy and tolerability. Riociguat is a valuable addition to the armamentarium of options for treating patients with PH.

Inspiratory Muscle Training Improves Inspiratory Muscle Strength and Functional Exercise Capacity in Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension: A Pilot Randomised Controlled Study

BACKGROUND

Exercise intolerance is present even in the early stages of pulmonary arterial hypertension (PAH) and is associated with poorer prognosis. Respiratory muscle dysfunction is common and may contribute to exercise limitation. We sought to investigate the effects of inspiratory muscle training (IMT) to improve exercise capacity in PAH.

METHODS

Adults with PAH were prospectively recruited and randomly assigned to either IMT or a control group. At baseline and after 8 weeks, assessment of respiratory muscle function, pulmonary function, neurohormonal activation, 6-minute walk distance and cardiopulmonary exercise testing variables were conducted. Inspiratory muscle strength was assessed by maximal static inspiratory pressure (PImax). The IMT group performed two cycles of 30 breaths at 30-40% of their PImax 5 days a week for 8 weeks.

RESULTS

Twelve (12) PAH patients (60±14 years, 10 females) were recruited and randomised (six in the IMT group and six in the control group). After 8 weeks, the IMT group improved PImax by 31 cmH₂O compared with 10 cmH₂O in controls, p=0.02. Following IMT, 6-minute walk distance improved by 24.5 m in the IMT group and declined by 12 m in the controls (mean difference 36.5 m, 95% CI 3.5-69.5, p=0.03). There was no difference in peak oxygen uptake between-groups (mean difference 0.4 mL/kg/min, 95% CI -2.6 to 3.4, p=0.77). There was no difference in the mean change between-groups in neurohormonal activation or pulmonary function.

CONCLUSION

In this pilot randomised controlled study, IMT improved PImax and 6-minute walk distance in PAH patients.

Effects of upper extremity aerobic exercise training on oxygen consumption, exercise capacity, dyspnea and quality of life in patients with pulmonary arterial hypertension

BACKGROUND

Pulmonary and extrapulmonary impairments are prevalent in pulmonary arterial hypertension (PAH) which is a rare, chronic and progressive disease.

OBJECTIVES

To investigate the effects of upper extremity aerobic exercise training on exercise capacity, oxygen consumption, dyspnea and quality of life in patients with PAH.

METHODS

In a prospective, randomized controlled, double-blinded study, eleven patients in training group applied upper extremity aerobic exercise training (50-80% of maximal heart rate), 15-45 min/day, 3 days a week for 6 weeks and 11 patients in control group alternating active upper extremity exercises for the same period. Exercise capacity evaluated using six minute walk test (6MWT), oxygen consumption simultaneously measured during 6MWT using a portable instrument, dyspnea modified Borg scale and Modified Medical Research Council dyspnea scale and quality of life Short Form 36 Health Survey, before and after the exercise training.

RESULTS

Baseline characteristics of groups were similar (p>0.05). Dyspnea (p<0.001) and peak oxygen consumption (p = 0.031) were significantly improved in training group compared the controls. Dyspnea, exercise capacity, peak oxygen consumption, minute ventilation, tidal volume, end tidal carbon-dioxide pressure, and vitality, social functioning and role-physical were significantly improved within training group (p<0.05). Oxygen consumption at anaerobic threshold were significantly decreased within control group (p<0.05).

CONCLUSIONS

Upper extremity aerobic exercise training improves oxygen consumption, and decreases dyspnea perception. It is a safe and effective intervention in patients with PAH. (ClinicalTrials.gov registration: NCT02371733).

The role of cardiopulmonary exercise testing and training in patients with pulmonary hypertension: making the case for this assessment and intervention to be considered a standard of care

Introduction: Pulmonary hypertension (PH) is a broad pathophysiological disorder primarily characterized by increased pulmonary vascular resistance due to multiple possible etiologies. Patients typically present with multiple complaints that worsen as disease severity increases. Although initially discouraged due to safety concerns, exercise interventions for patients with PH have gained wide interest and multiple investigations have established the effective role of exercise training in improving the clinical profile, exercise tolerance, and overall quality of life.Areas covered: In this review, we discuss the pathophysiology of PH during rest and exercise, the role of cardiopulmonary exercise testing (CPX) in the diagnosis and prognosis of PAH, the role of exercise interventions in this patient population, and the expected physiological adaptations to exercise training.Expert opinion: Exercise testing, in particular CPX, provides a wealth of clinically valuable information in the PH population. Moreover, the available evidence strongly supports the safety and efficacy of exercise training as a clinical tool in improving exercise tolerance and quality of life. Although clinical trials investigating the role of exercise in this PH population are relatively few compared to other chronic conditions, current available evidence supports the clinical implementation of exercise training as a safe and effective treatment modality.

Test-retest reliability and validity of the timed up and go test and 30-second sit to stand test in patients with pulmonary hypertension

BACKGROUND

Timed up and go (TUG) and sit to stand (STS) tests that required less space and easier to be performed in respiratory and cardiac diseases for assessing functionality. Aim was to test the reliability of TUG and 30-second STS (30STS) tests and determine the validity of TUG and 30STS tests in patients with Pulmonary Hypertension (PH).

METHODS

Thirty-eight patients with diagnosed PH were included. We collected TUG, 30STS, quadriceps muscle strength, physical activity level, and 6MWT. Intra-class correlation coefficient (ICC) was used to determine test-retest reliability and correlations with quadriceps muscle strength, physical activity level and 6MWT for validity of the TUG and 30STS tests.

RESULTS

The TUG and 30STS tests were associated with age, functional class, muscle strength, physical activity and functional exercise capacity in patients with PAH (p < 0.05). 6MWT was associated with age, functional class, muscle strength, physical activity and functional exercise capacity (p < 0.05). ICC (95%) for TUG test and 30STS were 0.96 (0.93-0.98) and 0.95 (0.90-0.97), respectively.

CONCLUSIONS

The TUG and 30STS tests were reliable and valid tests for measuring physical performance in PH. This study supports using the TUG and 30STS tests as practical assessment tools in patients with PH.

Exercise-based evaluations and interventions for pulmonary hypertension with connective tissue disorders

INTRODUCTION

Exercise intolerance is a common and often significant limitation in pulmonary arterial hypertension (PAH). This intolerance greatly affects the quality of life and function of the individual with PAH, irrespective of its etiology. In PAH associated with connective tissue disorders (PAH-CTD), exercise intolerance is further amplified by the presence of coexisting musculoskeletal manifestations of CTD. The evaluation of exercise capacity and prescription for exercise training therefore becomes a challenge to the clinician. Areas covered: This review highlights factors contributing to exercise intolerance in PAH-CTD, evaluation methods of exercise capacity and an overview on exercise training and a roadmap for future research. Expert commentary: Exercise intolerance is a complex interplay of cardiovascular, pulmonary, and musculoskeletal systems. Data from cardiopulmonary exercise tests have shown predictive abilities for both diagnosis and prognosis. In its absence, the 6-min walk test can be used to provide similar information thereby making the role of exercise testing an invaluable evaluation method in PAH-CTD. Exercise training data in PAH-CTD are still sparse, though, data from PAH studies suggest potential benefit. However, more research is required in this area of testing and training for greater understanding on exercise hemodynamic, phenotypes, and training benefits.

Cardiopulmonary rehabilitation program impact on prognostic markers in selected patients with resting and exercise-induced ventilatory inefficiency: a clinical trial

[Purpose] Ventilatory limitation is a common problem in patients with chronic heart failure and pulmonary hypertension. Excess ventilation may arise from augmented ventilatory drive, over activity of chemoreceptors and muscle ergoreceptors, or premature onset of lactic acidosis. Exertional dyspnea can cause limitations in the activities of daily living and as a result, reduced quality of life for these patients. The aim of the present study was to evaluate the effect of cardiopulmonary rehabilitation program on ventilatory efficiency for these patients. [Subjects and Methods] Twenty five patients with chronic heart failure and twenty five patients with pulmonary hypertension and only forty of them completed the study. The training program consisted of interval aerobic training program, based on the results of cardiopulmonary exercise testing. Training period was about five months. Outcomes were ventilatory equivalent for CO2, (VE/VCO2 at anaerobic threshold), VO2 at anaerobic threshold, VO2 max and peak work load. Echocardiography parameters were also measured; right ventricular systolic pressure for patients with pulmonary hypertension and ejection fraction for patients with chronic heart failure. [Results] Both groups showed an improvement in ventilation during exercise in favor of patients with pulmonary hypertension. VE/VCO2 decreased by 6.65 in pulmonary hypertension and by 2.9 in chronic heart failure. Right ventricular systolic pressure decreased by 12.05 mmHg in pulmonary hypertension and ejection fraction increased by 17.74% in chronic heart failure. [Conclusion] Physical therapy cardiopulmonary rehabilitation should be considered in managing patients with ventilatory limitation such as pulmonary hypertension and chronic heart failure.

Effects of exercise training on pulmonary hemodynamics, functional capacity and inflammation in pulmonary hypertension

Pulmonary hypertension (PH) is characterized by severe exercise limitation mainly attributed to the impairment of right ventricular function resulting from a concomitant elevation of pulmonary vascular resistance and pressure. The unquestioned cornerstone in the management of patients with pulmonary arterial hypertension (PAH) is specific vasoactive medical therapy to improve pulmonary hemodynamics and strengthen right ventricular function. Nevertheless, evidence for a beneficial effect of exercise training (ET) on pulmonary hemodynamics and functional capacity in patients with PH has been growing during the past decade. Beneficial effects of ET on regulating factors, inflammation, and metabolism have also been described. Small case-control studies and randomized clinical trials in larger populations of patients with PH demonstrated substantial improvements in functional capacity after ET. These findings were accompanied by several studies that suggested an effect of ET on inflammation, although a direct link between this effect and the therapeutic benefit of ET in PH has not yet been demonstrated. On this background, the aim of the present review is to describe current concepts regarding the effects of exercise on the pulmonary circulation and pathophysiological limitations, as well as the clinical and mechanistic effects of exercise in patients with PH.

Exercise-based rehabilitation programmes for pulmonary hypertension

BACKGROUND

Individuals with pulmonary hypertension (PH) have reduced exercise capacity and quality of life. Despite initial concerns that exercise training may worsen symptoms in this group, several studies have reported improvements in functional capacity and well-being following exercise-based rehabilitation in PH.

OBJECTIVES

To assess the efficacy and safety of exercise-based rehabilitation for people with PH. Primary outcomes were exercise capacity, adverse events during the intervention period and health-related quality of life (HRQoL). Secondary outcomes included cardiopulmonary haemodynamics, functional class, clinical worsening during follow-up, mortality and changes in B-type natriuretic peptide.

SEARCH METHODS

We searched the Cochrane Airways Specialised Register of Trials up to August 2016, which is based on regular searches of CINAHL, AMED, Embase, PubMed, MEDLINE, PsycINFO and registries of clinical trials. In addition we searched CENTRAL and the PEDro database up to August 2016 and handsearched relevant journals.

SELECTION CRITERIA

All randomised controlled trials (RCTs) focusing on exercise-based rehabilitation programmes for PH.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. For binary outcomes, we calculated odds ratios and their 95% confidence interval (CI), on an intention-to-treat basis. For continuous data, we estimated the mean difference (MD) between groups and its 95% CI. We employed a random-effects model for analyses. We assessed risk of bias for included studies and created 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included six RCTs and were able to extract data from five studies. The majority of participants were Group I pulmonary artery hypertension (PAH). Study duration ranged from three to 15 weeks. Exercise programmes included both inpatient- and outpatient-based rehabilitation that incorporated both upper and lower limb exercise. The mean six-minute walk distance following exercise training was 60.12 metres higher than control (30.17 to 90.07 metres, n = 165, 5 RCTs, low-quality evidence; minimal important difference was 30 metres), the mean peak oxygen uptake was 2.4 ml/kg/minute higher (1.4 to 3.4 ml/kg/min, n = 145, 4 RCTs, low-quality evidence) and the mean peak power in the intervention groups was 16.4 W higher (10.9 to 22.0 higher, n = 145, 4 RCTs, low-quality evidence). The mean change in HRQoL for the SF-36 physical component score was 4.63 points higher (0.80 to 8.47 points, n = 33, 2 RCTs, low-quality evidence) and for the SF-36 mental component score was 4.17 points higher (0.01 to 8.34 points; n = 33; 2 RCTs, low-quality evidence). One study reported a single adverse event, where a participant stopped exercise training due to lightheadedness.

AUTHORS' CONCLUSIONS

In people with PH, exercise-based rehabilitation results in clinically relevant improvements in exercise capacity. Exercise training was not associated with any serious adverse events. Whilst most studies reported improvements in HRQoL, these may not be clinically important. Overall, we assessed the quality of the evidence to be low. The small number of studies and lack of information on participant selection makes it difficult to generalise these results across the spectrum of people with PH.

Pulmonary vascular and cardiac impairment in interstitial lung disease

Pulmonary vascular and cardiac impairment is increasingly appreciated as a major adverse factor in the natural history of interstitial lung disease. This clinically orientated review focuses on the current concepts in the pathogenesis, pathophysiology and implications of the detrimental sequence of increased pulmonary vascular resistance, pre-capillary pulmonary hypertension and right heart failure in interstitial lung disease, and provides guidance on its management.

Development of pulmonary hypertension is a major adverse factor in the natural history of interstitial lung diseasehttp://ow.ly/nJB0302XAmD

Evidence on Exercise Training in Pulmonary Hypertension

Pulmonary hypertension (PH) is a chronic, debilitating condition which gravely affects exercise tolerance and quality of life. Though most therapies focus purely on medical intervention, there is a growing body of evidence to suggest the role and benefits of exercise training. This chapter discusses the various physiological basis for exercise intolerance observed in PH and highlights the rationale for exercise training. Recent evidence related to exercise training is summarized and potential pathways to suggest adaptations to exercise training are put forward. While keeping the paper applicable to clinicians, details on evaluating exercise intolerance, prescribing exercise and setting up rehabilitation centers for PH are discussed.

The effects of antihypertensive medications on physical function

Objective

Limited research has examined the effects of antihypertensive medication use and physical function. These studies provided mixed findings while employing a convenience sample and limiting their examination to few indices of physical function and few classes of antihypertensive medications. The purpose of this study was to examine whether several antihypertensive medication classes were associated with several measures of physical function in a national sample of U.S. middle-to-older age adults.

Methods

Data from the 1999–2002 and 2011–2012 NHANES were used. Antihypertensive medication use was assessed from an interviewer, and included angiotensin converting enzyme (ACE) inhibitors, peripherally-acting antiadrenergic agents and centrally-acting antiadrenergic agents. Physical function-related parameters included objectively-measured lower extremity isokinetic knee extensor strength (IKES), objectively-measured grip strength, laboratory-assessed walking performance (8 and 20 ft walk tests) and self-reported physical activity engagement.

Results

Those on ACE inhibitors had a 37% reduced odds (OR = 0.63, 95% CI: 0.48–0.83, P = .002) of engaging in moderate-to-vigorous physical activity, had reduced knee extensor strength (β = − 15.4, 95% CI: − 27.2 to − 3.4, P = .01) and took longer to complete the 20 ft (β = .42, 95% CI: 0.02–0.81, P = .04) and 8 ft walking tests (β = .22, 95% CI: 0.05–0.39, P = .01). Those on peripherally-acting antiadrenergic agents had reduced grip strength (β = − 4.8, 95% CI: − 9.1 to − 0.5, P = .02).

Conclusions

Antihypertensive medication use, particularly ACE inhibitors, is associated with various measures of reduced physical function. Clinicians are encouraged to monitor the long-term mobility function of their patients on antihypertensive medications.

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A national sample was employed.

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Numerous physical function parameters were evaluated.

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Antihypertensive medication use was associated with reduced physical function.

Exercise intolerance in pulmonary hypertension: mechanism, evaluation and clinical implications

INTRODUCTION

Exercise intolerance in pulmonary hypertension (PH) is a major factor affecting activities of daily living and quality of life. Evaluation strategies (i.e., non-invasive and invasive tests) are integral to providing a comprehensive assessment of clinical and functional status. Despite a growing body of literature on the clinical consequences of PH, there are limited studies discussing the contribution of various physiological systems to exercise intolerance in this patient population.

AREAS COVERED

This review, through a search of various databases, describes the physiological basis for exercise intolerance across the various PH etiologies, highlights the various exercise evaluation methods and discusses the rationale for exercise training amongst those diagnosed with PH. Expert commentary: With the growing importance of evaluating exercise capacity in PH (class 1, Level C recommendation), understanding why exercise performance is altered in PH is crucial. Thus, the further study is required for better quality evidence in this area.

Respiratory and limb muscle dysfunction in pulmonary arterial hypertension: a role for exercise training?

Respiratory and limb muscle dysfunction is emerging as an important pathophysiological abnormality in pulmonary arterial hypertension (PAH). Muscle abnormalities appear to occur frequently and promote dyspnea, fatigue, and exercise limitation in patients with PAH. Preliminary data suggest that targeted muscle training may be of benefit, although further evidence is required to consolidate these findings into specific recommendations for exercise training in patients with PAH. This article reviews the current evidence on prevalence, risk factors, and implications of respiratory and limb muscle dysfunction in patients with PAH. It also reviews the impact of exercise rehabilitation on morphologic, metabolic, and functional muscle profile and outcomes in PAH. Future research priorities are highlighted.

Functional exercise capacity, physical activity, and respiratory and peripheral muscle strength in pulmonary hypertension according to disease severity

[Purpose] This study investigated functional capacity, physical activity, and respiratory and peripheral muscle strength in different functional classes of pulmonary arterial hypertension (PAH) compared with healthy subjects. [Subjects and Methods] This study included 31 patients with class II (n = 16) or class III (n = 15) PAH, classified according to the World Health Organization. Fifteen healthy subjects served as controls. Functional capacity was assessed using the 6-minute walk test (6MWT). Physical activity was determined using the International Physical Activity Questionnaire Short Form (IPAQ-SF). Respiratory muscle strength was measured using a mouth pressure device. Peripheral muscle strength was evaluated using a dynamometer. [Results] The 3 groups had similar demographic variables (p > 0.05). There were significant differences in 6MWT distance, maximal inspiratory pressure, and IPAQ categorical classification between the 3 groups (p < 0.05). Maximal expiratory pressure; total IPAQ score; and knee extensor, shoulder abductor, and hand grip strength were significantly lower in PAH patients (classes II and III) than in healthy subjects (p < 0.05). [Conclusion] As PAH progresses, respiratory muscle strength, functional exercise capacity, and physical activity decrease. Functional class should be taken into consideration when planning rehabilitation programs for this patient group.

microRNA and Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a lethal vasculopathy associated with complex etiology that involves remodeling of distal pulmonary arteries leading to elevation of pulmonary vascular resistance. This process results in right ventricular (RV) hypertrophy and ultimately RV failure. In addition, PAH is associated with systemic impairment in the skeletal muscle contributing to exercise intolerance. It has only been a few decades since microRNAs (miRNAs) have been implied in the development and progression of PAH regarding every organ affected by the disease. Indeed, impairment of miRNA's expression has been involved in vascular cell remodeling processes such as adventitial fibroblast (AdvFB) migration; pulmonary arterial smooth muscle cell (PASMC) proliferation and pulmonary arterial endothelial cell (PAEC) dysfunction observed in PAH. At the molecular level miRNAs have been described in the control of ion channels and mitochondrial function as well as the regulation of the BMPR2 signaling pathways contributing to PAH lung impairment. Recently miRNAs have also been specifically implicated in RV dysfunction and systemic angiogenic impairment, observed in PAH. In this chapter, we will summarize the knowledge on miRNA in PAH and highlight their crucial role in the etiology of this disease.

Benefits of intensive treadmill exercise training on cardiorespiratory function and quality of life in patients with pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) restricts the ability to engage in physical activity and decreases longevity. We examined the impact of aerobic exercise training on function and quality of life in patients with World Health Organization group 1 PH.

METHODS

Patients were randomized to a 10-week education only (EDU) or education/exercise combined (EXE) group. The exercise program consisted of 24-30 sessions of treadmill walking for 30-45 min per session at 70% to 80% of heart rate reserve. Outcome variables included changes in 6-min walk test (6MWT) distance, time to exercise intolerance, peak work rate (WR) from a cardiopulmonary treadmill test, and quality-of-life measures, including the Short Form Health Survey, version 2 (SF-36v2) and Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR).

RESULTS

Data are presented as mean SD. Twenty-three women (age, 54 11 years; BMI, 31 7 kg/m 2 ) were randomized to the EDU (n 5 13) or EXE (n 5 10) groups. Following 10 weeks of intervention, patients in the EXE group demonstrated an improvement in 6MWT distance (56 45 m; P 5 .002), increased time to exercise intolerance (1.9 1.3 min; P 5 .001), and peak WR (26 23 W; P 5 .004). Additionally, the EXE group scored significantly ( P , .050) better on six of the eight scales on SF-36v2, and fi ve of the six scales on CAMPHOR. In contrast, no significant improvement was observed for any of the outcome measures following EDU. No adverse events were noted in either group.

CONCLUSION

Ten weeks of brisk treadmill walking improved 6MWT distance, cardiorespiratory function, and patient-reported quality of life in female patients with group 1 PH.