Is the 6-minute walk test a reliable substitute for peak oxygen uptake in patients with dilated cardiomyopathy?

Usefulness of oxygen uptake efficiency slope in a 6 min walk test in chronic heart failure

AIMS

Frailty is an obstacle to performing cardiopulmonary exercise test (CPET) in patients with chronic heart failure (CHF). We evaluated the usefulness of oxygen uptake efficiency slope (OUES) using a 6 min walk test (6MWT) with portable gas analysis compared with CPET-derived parameters in patients with CHF.

METHODS AND RESULTS

Patients with CHF who underwent both the 6MWT with portable gas analysis and CPET between December 2016 and May 2020 were retrospectively investigated. The 6MWT-derived and echocardiographic parameters were compared with the OUES and peak oxygen consumption (VO2) from the CPET. Forty patients were analysed; 50% were male with a mean age of 55.45 ± 14.70 years. Twenty-six patients (65%) had New York Heart Association Functional Classification II or III dyspnoea. Twenty-five patients (62.5%) had heart failure (HF) with preserved ejection fraction (EF) (left ventricular EF > 50%), and nine patients (22.5%) had HF with reduced EF (EF < 40%). During the 6MWT, the peak VO2 was 14.97 ± 3.80 mL/kg/min, which was only 74% of the peak VO2 in the CPET, 20.18 ± 5.64 mL/kg/min. The OUES in the 6MWT was lower than that in the CPET (1528.87 ± 579.01 in the 6MWT vs. 1638.69 ± 601.31 in the CPET). The 6 min walk distance (6MWD) and OUES in the 6MWT were positively correlated with the OUES in the CPET (6MWD, r = 0.434, P = 0.005; OUES, r = 0.729, P < 0.001). The OUES in the 6MWT showed the strongest correlation with the OUES in the CPET. When we divided patients into two groups according to peak VO2 in the CPET, the correlation between OUES values of the 6MWT and that of the CPET was consistently confirmed (peak VO2 ≥ 20 mL/kg/min group, r = 0.661, P = 0.001; peak VO2 < 20 mL/kg/min group, r = 0.526, P = 0.021). In addition, the 6MWD, OUES, and peak VO2 in the 6MWT were associated with peak VO2 in the CPET (6MWD, r = 0.627, P < 0.001; OUES, r = 0.452, P = 0.003; and peak VO2, r = 0.492, P = 0.001).

CONCLUSIONS

In frail patients with CHF who have difficulty performing maximal exercises, the OUES through the 6MWT may be applied instead of the OUES and peak VO2 from the CPET.

Delivering effective, comprehensive, multi-exercise component cardiac rehabilitation (CR) for chronic heart failure patients in low resource settings in sub-Saharan Africa: Queen Elizabeth Central Hospital-(QECH-CR) randomised CR study, Malawi

BACKGROUND

The delivery of Cardiac Rehabilitation (CR) and attaining evidence-based treatment goals are challenging in developing countries, such as Malawi. The aims of this study were to (i) assess the effects of exercise training/ CR programme on cardiorespiratory and functional capacity of patients with chronic heart failure (CHF), and (ii) examine the effectiveness of a novel, hybrid CR delivery using integrated supervised hospital- and home-based caregiver approaches.

METHODS

A pre-registered (UMIN000045380), randomised controlled trial of CR exercise therapy in patients with CHF was conducted between September 2021 and May 2022. Sixty CHF participants were randomly assigned into a parallel design-exercise therapy (ET) (n = 30) or standard of care (n = 30) groups. Resting hemodynamics, oxygen saturation, distance walked in six-minutes (6MWD) and estimated peak oxygen consumption (VO2 peak) constituted the outcome measures. The exercise group received supervised, group, circuit-based ET once weekly within the hospital setting and prescribed home-based exercise twice weekly for 12 weeks. Participants in both arms received a group-based, health behaviour change targeted education (usual care) at baseline, 8-, 12- and 16-weeks.

RESULTS

Most of the participants were female (57%) with a mean age of 51.9 ±15.7 years. Sixty-five percent (65%) were in New York Heart Association class III, mostly with preserved left ventricular ejection fraction (HFpEF) (mean Left Ventricular Ejection Fraction 52.9 ±10.6%). The 12-weeks ET led to significant reductions in resting haemodynamic measures (all P <0.05). The ET showed significantly higher improvements in the 6MWD (103.6 versus 13.9 m, p<0.001) and VO2 peak (3.0 versus 0.4 ml·kg-1·min-1, p <0.001). Significant improvements in 6MWD and VO2 peak (both p<0.001), in favour of ET, were also observed across all follow-up timepoints.

CONCLUSION

This novel, randomised, hybrid ET-based CR, delivered to mainly HFpEF patients using an integrated hospital- and home-based approach effectively improved exercise tolerance, cardiorespiratory fitness capacities and reduced perceived exertion in a resource-limited setting.

Taking a walk on the heart failure side: comparison of metabolic variables during walking and maximal exertion

AIMS

Although cardiopulmonary exercise testing (CPET) is the gold standard to assess exercise capacity, simpler tests (i.e., 6-min walk test, 6MWT) are also commonly used. The aim of this study was to evaluate the relationship between cardiorespiratory parameters during CPET and 6MWT in a large, multicentre, heterogeneous population.

METHODS

We included athletes, healthy subjects, and heart failure (HF) patients of different severity, including left ventricular assist device (LVAD) carriers, who underwent both CPET and 6MWT with oxygen consumption measurement.

RESULTS

We enrolled 186 subjects (16 athletes, 40 healthy, 115 non-LVAD HF patients, and 15 LVAD carriers). CPET-peakV̇O2 was 41.0 [35.0-45.8], 26.2 [23.1-31.0], 12.8 [11.1-15.3], and 15.2 [13.6-15.6] ml/Kg/min in athletes, healthy, HF patients, and LVAD carriers, respectively (P < 0.001). During 6MWT they used 63.5 [56.3-76.8], 72.0 [57.8-81.0], 95.5 [80.3-109], and 95.0 [92.0-99.0] % of their peakV̇O2, respectively. None of the athletes, 1 healthy (2.5%), 30 HF patients (26.1%), and 1 LVAD carrier (6.7%), reached a 6MWT-V̇O2 higher than their CPET-peakV̇O2. Both 6MWT-V̇O2 and walked distance were significantly associated with CPET-peakV̇O2 in the whole population (R2 = 0.637 and R2 = 0.533, P ≤ 0.001) but not in the sub-groups. This was confirmed after adjustment for groups.

CONCLUSIONS

The 6MWT can be a maximal effort especially in most severe HF patients and suggest that, in absence of prognostic studies related to 6MWT metabolic values, CPET should remain the first method of choice in the functional assessment of patients with HF as well as in sport medicine.

A Simple Equation to Estimate Maximal Oxygen Uptake in Older Adults Using the 6 min Walk Test, Sex, Age and Body Mass Index

PURPOSE

The 6 min walk test (6MWT) is used in clinical and epidemiological practice as a simple tool to evaluate the maximal aerobic exercise capacity (VO2max). To date, little evidence has been provided regarding regression equation models to predict VO2max in older adults. Therefore, the main purpose of the study was to develop a reference equation to estimate objectively measured VO2max, based on the 6MWT, sex, age and body mass index (BMI).

PATIENTS AND METHODS

In this observational prospective study, we collected the data from 233 asymptomatic participants aged 60-80 years (52.4% women). VO2max and the 6MWT were measured using standardized protocols. BMI was calculated as weight (kg) divided by height squared (m2). To be able to develop the predictive equation for VO2max, we used linear generalized estimating equations (GEE).

RESULTS

Older men performed better in VO2max (30.9 ± 8.8 vs. 26.3 ± 6.3 mL/kg/min, p < 0.001) and the 6MWT (673.9 ± 58.7 vs. 642.3 ± 48.0 m, p < 0.001), compared to women. VO2max was correlated with the 6MWT (r = 0.71, p < 0.001), sex (r = -0.29, p < 0.001), age (r = -0.62, p < 0.001) and BMI (r = -0.38, p < 0.001). The model to predict VO2max included: VO2max (mL/kg/min) = 59.44 - 3.83 *, sex (1-men; 2-women) - 0.56 *, age (years) - 0.48 *, BMI (kg/m2) + 0.04 *, and the 6MWT (m) (R = 0.85; R2 = 72.3%, SEE = 3.99 mL/kg/min, p < 0.001).

CONCLUSION

The newly developed regression equation can be a guideline in clinical and epidemiological practice to predict the VO2max in apparently healthy older adults.

Cardiac MRI-based right-to-left ventricular blood pool T2 relaxation times ratio correlates with exercise capacity in patients with chronic heart failure

BACKGROUND

MRI T2 mapping has been proven to be sensitive to the level of blood oxygenation. We hypothesized that impaired exercise capacity in chronic heart failure is associated with a greater difference between right (RV) to left ventricular (LV) blood pool T2 relaxation times due to a higher level of peripheral blood desaturation, compared to patients with preserved exercise capacity and to healthy controls.

METHODS

Patients with chronic heart failure (n = 70) who had undergone both cardiac MRI (CMR) and a 6-min walk test (6MWT) were retrospectively identified. Propensity score matched healthy individuals (n = 35) served as control group. CMR analyses included cine acquisitions and T2 mapping to obtain blood pool T2 relaxation times of the RV and LV. Following common practice, age- and gender-adjusted nominal distances and respective percentiles were calculated for the 6MWT. The relationship between the RV/LV T2 blood pool ratio and the results from 6MWT were evaluated by Spearman's correlation coefficients and regression analyses. Inter-group differences were assessed by independent t-tests and univariate analysis of variance.

RESULTS

The RV/LV T2 ratio moderately correlated with the percentiles of nominal distances in the 6MWT (r = 0.66) while ejection fraction, end-diastolic and end-systolic volumes showed no correlation (r = 0.09, 0.07 and - 0.01, respectively). In addition, there were significant differences in the RV/LV T2 ratio between patients with and without significant post-exercise dyspnea (p = 0.001). Regression analyses showed that RV/LV T2 ratio was an independent predictor of the distance walked and the presence of post-exercise dyspnea (p < 0.001).

CONCLUSION

The proposed RV/LV T2 ratio, obtained by two simple measurements on a routinely acquired four-chamber T2 map, was superior to established parameters of cardiac function to predict exercise capacity and the presence of post-exercise dyspnea in patients with chronic heart failure.

Mind Your Heart-II: Protocol for a behavioral randomized controlled trial of mindfulness training to promote self-care in patients with comorbid heart failure and cognitive impairment

BACKGROUND

Heart failure (HF) self-care is a robust predictor of prognosis in HF patients. Cognitive impairment is a common comorbidity in HF patients and constitutes a major challenge to HF self-care. Mindfulness training (MT) has been shown to improve cognitive function and interoception, two components essential to promoting effective HF self-care.

OBJECTIVES

The aims of the Mind Your Heart-II (MYH-II) study are to investigate the effects of MT on HF self-care via changes in cognitive function and interoception in patients with comorbid HF and cognitive impairment, and to study the process by which MT can improve cognitive function via vagal control. We hypothesize that MT will improve cognitive function, interoception, and vagal control, resulting in enhanced HF self-care, compared to control participants.

METHODS

MYH-II is a mechanistic parallel phase II behavioral randomized controlled trial. We will enroll 176 English or Spanish-speaking patients with comorbid chronic HF and mild cognitive impairment. Participants will be randomized to either: (1) 8-week phone-delivered MT + Enhanced Usual Care (EUC), or (2) EUC alone. Participants will complete baseline, end-of-treatment (3 months), and follow-up (9 months) assessments. The primary outcome is cognitive function (NIH Toolbox Fluid Cognition Composite Score). Additional key outcomes include: interoception (heartbeat tracking task, Multidimensional Assessment of Interoceptive Awareness), HF self-care (Self-Care of Heart Failure Index v7.2), and vagal control (high-frequency heart rate variability).

IMPLICATIONS

If study hypotheses are confirmed, phone-based MT may be a key tool for improving HF self-care, and possibly clinical outcomes, in HF patients with comorbid cognitive impairment.

Early Heart Rate Recovery after a 6-min Walking Test Predicts Clinical Benefits in Patients after Percutaneous Aortic Valve Implantation

BACKGROUND

It was hypothesized that the time-appropriate return to a resting heart rate (HR) after cessation of exercise could be a marker for predicting outcomes in patients with heart failure (HF). We aimed to evaluate the prognostic value of HR recovery in functional improvement among adults with severe aortic stenosis undergoing percutaneous aortic valve implantation (TAVI).

METHODS

We performed a 6 min walk test (6MWT) in 93 individuals before TAVI and 3 months after the procedure. The change in walking distance was calculated. During the pre-TAVI 6MWT, we analyzed the differences between baseline HR, HR at the end of the test, and HR at the 1st, 2nd, and 3rd minute of recovery.

RESULTS

After 3 months, 6MWT distances improved by 39 ± 63 m and reached a total of 322 ± 117 m. Multiple linear regression proved the differences between HR after 2 min of recovery and baseline HR in pre-TAVI after a 6MWT was the only significant predictor of waking distance improvement during follow-up.

CONCLUSIONS

Our study suggests that analysis of HR recovery after a 6MWT may be a helpful and easy parameter to assess improvements in exercise capacity after TAVI. This simple method can help to identify patients in whom no significant benefit in functional improvement can be expected despite successful valve implantation.

Effect of Dapagliflozin on Exercise Capacity and Cardiovascular Risk in Patients with Heart Failure

Heart failure (HF) is a serious disorder that affects millions of people worldwide, with a high rate of exercise intolerance, rehospitalization, and death. HF has many underlying causes, including type 2 diabetes mellitus (T2DM), which corresponds with high mortality and short survival among patients with HF. Numerous studies have shown the crucial role of gliflozins, a new generation of blood glucose-lowering medications, in cardiac remodeling, with beneficial impacts on exercise capacity and cardiovascular (CV) mortality, even in non-diabetic individuals. The foundational CV-protective frameworks of these agents are intricate and multifaceted. Dapagliflozin is a new widely used drug and a valuable alternative for patients with T2DM and CV risk factors. Dapagliflozin was approved by the Food and Drug Administration (FDA) in 2019 to lower the risk of HF hospitalization in patients with concurrent T2DM and CV disease or associated risk factors. However, the effects of this new drug on exercise capacity and CV risk still need to be elucidated. The primary objective of this review is to summarize the effect of dapagliflozin on exercise capacity and CV risk in patients with HF.

Two-minute walk distance reference equations for middle-aged and elderly Chinese individuals with obesity

Background and objective

While the six-minute walk test (6MWT) is often used to assess exercise capacity, the less well-known two-minute walk test (2MWT) is more feasible for some patients. In previous studies, we developed reference equations for the two-minute walk distance (2MWD) for healthy Chinese adults. However, our study did not recruit people with obesity, and the reference equations did not apply to participants with a body mass index (BMI) > 30 kg/m². The main objective of this study was to establish reference equations for the 2MWD among middle-aged and elderly Chinese individuals with obesity.

Methods

A total of 295 individuals were recruited. The participants underwent two 2MWTs, with the longer of the two 2MWDs used for further analyses. The reference equations for the 2MWD were developed using stepwise multiple regression analysis. The newly established equations for the 2MWD were then compared with the existing equations.

Results

The mean 2MWD of the participants was 176±20 m. Age and BMI were identified as independent factors that influenced the 2MWD and explained 28% and 32% of the variance in walking distance for the male and female groups, respectively. The reference equations for the 2MWD were as follows:

Conclusion

This study resulted in the development of reference equations for predicting 2MWD among middle-aged and elderly Chinese people with obesity. These equations will be a clinically valuable tool for evaluating functional capacity, determining prognoses and monitoring treatment in middle-aged and elderly Chinese people with obesity.

Peak oxygen uptake and metabolic equivalents explained by six-minute walk test: A prospective observational study in predicting heart failure patient readmission

Background

Methods

Results

Conclusions

•

Functional capacity contributes to reducing cardiovascular events and re-hospitalization of patients with heart failure.

•

Conducting a 6-min walk test before patient discharge can help identify a patients' risk for readmission.

•

VO2max and METs can be utilized to create a comprehensive treatment flow for heart failure patients to prevent readmission.

Changes Observed in the 6-minute Walk Test in Response to Exercise-based Cardiac Rehabilitation

Objectives: The six-minute walk test (6MWT) is widely used in exercise based cardiac rehabilitation (EBCR) for assessment of functional capacity. The purpose of this study was to assess the effect of structured exercise in an EBCR program on 6MWT change and to determine the significance of age, gender, body mass index (BMI), pathology and exercise attendance on influencing this outcome.Methods: Data from a single centre 6-week (twice weekly exercise and education of one-hour duration) exercise-based cardiac rehabilitation program were analysed. Between 2006 and 2019, 2524 patients (males 1923, females 601, mean age 63.5 ± 11.2 years) with cardiovascular disease completed a pre and post 6MWT. Analysis included the effect of age, gender, pathology, BMI and exercise attendance on 6MWT outcome.Results: The group mean improvement in the 6MWT was 21.8% (pre 6MWT 432 ± 83, post 6MWT 527 ± 102 metres). The age-related improvement showed that both males and females achieved a post 6MWT results equivalent to the pre 6MWT result of patients two decades younger with improvement in the 6MWT unrelated to exercise attendance.Conclusions: The 6MWT provides simple safe method for assessment of functional capacity in an out-of-hospital environment being suitable for all ages. The post EBCR 6MWT results showed a group mean improvement in excess of 20% for both sexes. The decline per decade in 6MWT distance is less than 20 metres up to the sixth decade with a more marked decline from the sixth to the eighth decade, the decline being approximately 40-metres for both sexes in the eighth decade.

A randomized-controlled trial comparing supervised aerobic training to resistance training followed by unsupervised exercise on physical functioning in older breast cancer survivors

INTRODUCTION

This study compared the relative efficacy of aerobic training to resistance training on physical functioning in older breast cancer survivors and determined whether benefits could be maintained by transitioning to unsupervised home-based training.

MATERIALS AND METHODS

Early-stage, post-treatment, older (≥65 years) breast cancer survivors (n = 114; mean age 72 years) were randomized to 12 months of supervised aerobic (n = 37), resistance (n = 39) or stretching (active control; n = 38) training followed by 6 months of unsupervised home-based training. Outcomes included aerobic capacity by 6-min walk distance (6MWD; m), maximal upper and lower body strength (1-repetition maximum; kg); physical function by short physical performance battery (SPPB), SF-36 and Late Life Function and Disability Instruments.

RESULTS

Over 12-months of supervised exercise, all groups improved in muscle strength and SPPB scores, but resistance trained women also improved 6MWD. Improvements in upper and lower body strength in the resistance group were significantly greater than those in the stretching control (+2.5 kg vs. +1.8 kg; p = 0.05) and aerobic groups (+8.3 kg vs +2.7 kg; p = 0.047), respectively, with trends for greater improvements in 6MWD (+57.9 m vs. +22.5 m; p = 0.057) and self-report physical function (+4.8 vs. -4.4; 0.066) in resistance trained women versus controls. Compared to values at 12 months, there were no changes during unsupervised training in any measure within or between groups, except for self-reported advanced lower extremity function which improved in the resistance group and fell in the aerobic group (+1.3 vs. -3.1; p = 0.043).

DISCUSSION

Supervised exercise can improve strength and physical functioning among older breast cancer survivors. Resistance training may lead to better improvements compared to aerobic or flexibility training, whether in a supervised or unsupervised setting. Clinicaltrials.govNCT00662103.

Insufficient Post-operative Energy Intake Is Associated With Failure of Enhanced Recovery Programs After Laparoscopic Colorectal Cancer Surgery: A Prospective Cohort Study

Background: Although enhanced recovery after surgery (ERAS) has been proven to be beneficial after laparoscopic colorectal surgery, some of the patients may fail to complete the ERAS program during hospitalization. This prospective study aims to evaluate the risk factors associated with ERAS failure after laparoscopic colorectal cancer surgery.

Methods: This is a prospective study from a single tertiary referral hospital. Patients diagnosed with colorectal cancer who met the inclusion criteria were included in this study. Demographic and clinicopathological characteristics were collected. Post-operative activity time and 6-min walking distance (6MWD) were measured. Patients were divided into ERAS failure group and ERAS success according to decreased post-operative activity and 6MWD. Factors associated with ERAS failure were investigated by univariate and multivariate analysis.

Results: A total of 91 patients with colorectal cancer were included. The incidence of ERAS failure is 28.6% among all patients. Patients in ERAS failure group experienced higher rate of post-operative ileus and prolonged hospital stay (p < 0.001). Multivariate analysis revealed that older age (p = 0.006), body mass index ≥25.5 kg/m² (p = 0.037), smoking (p = 0.002), operative time (p = 0.048), and post-operative energy intake <18.5 kcal/kg•d (p = 0.045) were independent risk factors of ERAS failure after laparoscopic colorectal surgery.

Conclusions: Our findings indicated that a proportion of patients may fail the ERAS program after laparoscopic colorectal surgery. We for the first time showed that post-operative energy intake was an independent risk factor for ERAS failure. This may provide evidence for further investigation on precise measurement of nutritional status and selected high-risk patients for enhanced nutrition support.

Effect of Sacubitril/Valsartan vs Standard Medical Therapies on Plasma NT-proBNP Concentration and Submaximal Exercise Capacity in Patients With Heart Failure and Preserved Ejection Fraction: The PARALLAX Randomized Clinical Trial

IMPORTANCE

There is limited evidence on the benefits of sacubitril/valsartan vs broader renin angiotensin system inhibitor background therapy on surrogate outcome markers, 6-minute walk distance, and quality of life in patients with heart failure and mildly reduced or preserved left ventricular ejection fraction (LVEF >40%).

OBJECTIVE

To evaluate the effect of sacubitril/valsartan on N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, 6-minute walk distance, and quality of life vs background medication-based individualized comparators in patients with chronic heart failure and LVEF of more than 40%.

DESIGN, SETTING, AND PARTICIPANTS

A 24-week, randomized, double-blind, parallel group clinical trial (August 2017-October 2019). Of 4632 patients screened at 396 centers in 32 countries, 2572 patients with heart failure, LVEF of more than 40%, elevated NT-proBNP levels, structural heart disease, and reduced quality of life were enrolled (last follow-up, October 28, 2019).

INTERVENTIONS

Patients were randomized 1:1 either to sacubitril/valsartan (n = 1286) or to background medication-based individualized comparator (n = 1286), ie, enalapril, valsartan, or placebo stratified by prior use of a renin angiotensin system inhibitor.

MAIN OUTCOMES AND MEASURES

Primary end points were change from baseline in plasma NT-proBNP level at week 12 and in the 6-minute walk distance at week 24. Secondary end points were change from baseline in quality of life measures and New York Heart Association (NYHA) class at 24 weeks.

RESULTS

Among 2572 randomized patients (mean age, 72.6 years [SD, 8.5 years]; 1301 women [50.7%]), 2240 (87.1%) completed the trial. At baseline, the median NT-proBNP levels were 786 pg/mL in the sacubitril/valsartan group and 760 pg/mL in the comparator group. After 12 weeks, patients in the sacubitril/valsartan group (adjusted geometric mean ratio to baseline, 0.82 pg/mL) had a significantly greater reduction in NT-proBNP levels than did those in the comparator group (adjusted geometric mean ratio to baseline, 0.98 pg/mL) with an adjusted geometric mean ratio of 0.84 (95% CI, 0.80 to 0.88; P < .001). At week 24, there was no significant between-group difference in median change from baseline in the 6-minute walk distance with an increase of 9.7 m vs 12.2 m (adjusted mean difference, -2.5 m; 95% CI, -8.5 to 3.5; P = .42). There was no significant between-group difference in the mean change in the Kansas City Cardiomyopathy Questionnaire clinical summary score (12.3 vs 11.8; mean difference, 0.52; 95% CI, -0.93 to 1.97) or improvement in NYHA class (23.6% vs 24.0% of patients; adjusted odds ratio, 0.98; 95% CI, 0.81 to 1.18). The most frequent adverse events in the sacubitril/valsartan group vs the comparator group were hypotension (14.1% vs 5.5%), albuminuria (12.3% vs 7.6%), and hyperkalemia (11.6% vs 10.9%).

CONCLUSIONS AND RELEVANCE

Among patients with heart failure and left ventricular ejection factor of higher than 40%, sacubitril/valsartan treatment compared with standard renin angiotensin system inhibitor treatment or placebo resulted in a significantly greater decrease in plasma N-terminal pro-brain natriuretic peptide levels at 12 weeks but did not significantly improve 6-minute walk distance at 24 weeks. Further research is warranted to evaluate potential clinical benefits of sacubitril/valsartan in these patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03066804.

Effect of the Active Cycle of Breathing Technique on Perioperative Outcome in Individuals With Esophagectomy: A Quasi-Experimental Study

Background: The effect of active cycle of breathing technique (ACBT) on EC patients has not been well elucidated. In this research, we aim to explore the effect of ACBT on the perioperative outcomes in patients with esophageal carcinoma who underwent esophagectomy. Methods: Patients who underwent esophagectomy in an academic institution from December 2017 to July 2019 were included in this study. In a quasi-experimental study, participants were randomly divided into an experimental group (active cycle of breathing technique, n = 107) and an observational group (n = 106) by drawing lots. The chi-squared test, Cochran-Mantel-Haenszel test, Logistic regression analysis, and Kruskal-Wallis test were used to analyze data. A two-sided P value <0.05 was considered statistically significant. The primary observational endpoint was the mean weight of the sputum. Other outcomes included the six-min-walk test (6MWT), Borg scale, anastomotic leakage, and the length of hospital stay. Results: 95 patients underwent minimally invasive surgery, and 118 patients received open surgery. There were 16 patients with anastomotic leakage in the present study, and we found that patients in the observational group had higher odds of anastomotic leakage. The results showed that the mean weight of the sputum in the observation group was lighter than that of the experimental group. After esophagectomy, the experimental group had better outcomes than the observation group (Borg scale: 2.448 vs. 1.547; 6-MWT: 372.811 vs. 425.355m, all P < 0.05). The mean length of hospital stay was longer in the observation group (17.953 days) than that in the experimental group (12.037 days, P = 0.01). We also found that the observational group had a higher discharge ratio over 2 weeks in all cohort (adjusted OR 2.487, 95% confidence intervals 1.147-5.392, P = 0.021). Conclusion: Active cycle of breathing technique may improve the perioperative outcomes and decrease the length of hospital stay after surgery in patients with esophageal cancer. However, we need more researches to validate these findings.

Impact of gender and age on 6-Minute Walking Test performance of patients with coronary heart disease compared to healthy elders

The performance of 6-minute walking test (6MWT) of patients with coronary heart disease (CHD) was significantly related to patients' cardiopulmonary functions. The 6MWT may provide prognostic information for patients. However, the impact of gender and age on the 6MWT performance and related cardiopulmonary parameters of patients with CHD compared to the healthy group has not be fully investigated and discussed. In this study, a total of 118 subjects, including 70 CHD patients and 48 healthy elders, were enrolled. The subjects performed the 6MWT while fourteen cardiopulmonary parameters were measured during the task and the walking distance was recorded at the end. Factors of gender, age, and disease on the 6MWT performance were analyzed using multivariate analysis of variance and the parameters between the patients and healthy people in age- and gender-specific subgroups were compared by Pearson's correlation coefficient. Results showed that age (60-65 and ≥65 years) and gender significantly influenced the 6MWT performance of subjects. Featured parameters were observed in older subgroups (≥65 years) between the patients and healthy people while patients aged 60-65 had similar 6MWT performance with the healthy control group. It would be potential to distinguish patients with CHD from healthy elders based on the 6MWT where factors of age and gender should be considered.

Validity of the 6-Minute Walk Test and YMCA Submaximal Cycle Test During Midpregnancy

Tinius, RA, Blankenship, M, Maples, JM, Pitts, BC, Furgal, K, Norris, ES, Hoover, DL, Olenick, A, Lambert, J, and Cade, WT. Validity of the 6-minute walk test and Young Men's Christian Association (YMCA) submaximal cycle test during midpregnancy. J Strength Cond Res 35(11): 3236-3242, 2021-Submaximal exercise testing can be a feasible alternative to maximal testing within special populations to safely predict fitness levels; however, submaximal exercise testing has not been well-validated for use during pregnancy. The purpose of this study was to determine the concurrent validity of the 6-minute walk test (6MWT) and the YMCA submaximal cycle test (YMCAT) to predict V̇o2max in physically active women during midpregnancy. Thirty-seven (n = 37) pregnant women (22.1 ± 1.4 weeks' gestation) and 10 (n = 10) nonpregnant women participated in the study. Subjects completed a graded maximal treadmill test at 1 visit to measure maximal oxygen consumption (V̇o2max), and then subjects completed the 6MWT and YMCAT in randomized order during a separate visit. The predicted V̇o2max from each submaximal test were compared with the measured V̇o2max from the treadmill test to assess the validity of these tests during pregnancy. Among pregnant women, predicted V̇o2max from the YMCAT was not correlated to the measured V̇o2max (r = 0.14, p = 0.42), and the predicted V̇o2max from the 6MWT was only moderately correlated (r = 0.40, p = 0.016) to the measured V̇o2max. Among nonpregnant women, the predicted V̇o2max values from both the YMCAT and the 6MWT had strong correlations with the measured V̇o2max values (YMCAT: r = 0.71, p = 0.02; 6MWT: r = 0.80, p = 0.006). Neither test demonstrated concurrent validity among the pregnant sample. The main finding is that the YMCAT is not a valid method to estimate V̇o2max during midpregnancy (likely due to physiological changes in heart rate [HR] during pregnancy). The 6MWT has potential to be used clinically for estimating fitness as actual and predicted values did positively correlate, and it is not dependent on HR responses to exercise. However, if a precise measure of fitness is needed, then neither test appears to have strong validity for use during midpregnancy.

Predisease Physical Activity Level and Current Functional Capacity in Patients With COVID-19: Relationship With Pneumonia and Oxygen Requirement

BACKGROUND

During the COVID-19 pandemic, restrictive measures can reduce physical activity. The purpose of this study was to evaluate predisease physical activity and current functional capacity in patients with and without the presence of pneumonia and oxygen requirement in Turkish survivors of COVID-19.

METHODS

Among the COVID-19 patients admitted to the hospital, 100 patients were selected. Data about predisease physical activity (by short-form International Physical Activity Questionnaire), oxygen requirement and presence of pneumonia, and current functional capacity (by the 6-min walking test) were collected. Continuous and categorical variables were compared with the Mann-Whitney U and χ2 test, respectively (P < .05).

RESULTS

The predisease physical activity levels and current functional capacity of patients with pneumonia and oxygen requirement were significantly lower than patients without pneumonia and oxygen requirement (P < .05). However, there was no significant difference between males and females (P > 0.05). Pneumonia and oxygen requirement was more common in the older adults (P < .05). Also, a significant correlation was found between age with predisease physical activity (r = .530, P = .000) and current functional capacity (r = -.346, P = .000) and predisease physical activity level with current functional capacity (r = .523, P = .001).

CONCLUSION

The physical activity level may be related to the severity of COVID-19 disease.

Bronchoscopic airway clearance therapy for acute exacerbations of bronchiectasis

Background

Persistent cough and large amounts of purulent sputum affects many bronchiectasis patients. No studies have evaluated the efficacy and safety of bronchoscopic airway clearance therapy and bronchoalveolar lavage (B-ACT) for non-cystic fibrosis bronchiectasis patients with acute exacerbation.

Methods

A randomised controlled trial was conducted to explore the efficacy and safety of B-ACT among 189 bronchiectasis inpatients from February 1, 2018 to February 28, 2019. The primary outcome was the time to first acute exacerbation. Secondary outcomes included changes of health-related scores, length of hospital stay, hospitalization expenses and incidences of adverse events.

Findings

B-ACT therapy significantly prolonged the median days to first acute exacerbation when compared with control group (198 vs 168 days, HR 0·555 (0·322-0·958), p=0·012; effect size(r)= 0·94). Further analysis showed that B-ACT therapy was more beneficial for these patients with severe disease and greater symptoms. COPD Assessment Test (CAT) scores improved significantly on the third day (5·45 vs 4·85, 0·60 (0·09-1·11), p=0·023), and Leicester Cough Questionnaire (LCQ) scores improved obviously on the third and seventh days (1·53 vs 1·23, 0·30 (0·05-0·55), p=0·044; 1·66 vs 1·32, 0·34 (0·08-0·60), p=0·022; respectively) after B-ACT therapy. Adverse events associated with B-ACT were mostly transient and mild. Differences of the lengths of hospital stay and hospitalization expenses in both group was not significant.

Interpretation

B-ACT therapy significantly prolonged the time to first acute exacerbation after discharge, highlighting the importance of B-ACT therapy focused on symptom improvements in preventing exacerbation.

Funding

National Natural Science Foundation of China.

Trial registry

ClinicalTrials.gov; No.:NCT03643302; URL: www.clinicaltrials.gov.

Prolonged heart rate recovery time after 6-minute walk test is an independent risk factor for cardiac events in heart failure: A prospective cohort study

OBJECTIVES

To determine whether the time for peak exercise heart rate to return to resting heart rate after the 6-minute walk test (6MWT) can predict cardiac events in patients with heart failure (HF) within 2 years.

DESIGN

Prospective cohort study.

SETTING

HF outpatient facility at a tertiary teaching hospital.

PARTICIPANTS

Seventy-six patients with HF, New York Heart Association functional classification II and III, and left ventricular ejection fraction <50%.

MAIN OUTCOME MEASURES

Patients used a heart rate monitor to measure the time for peak exercise heart rate to return to resting heart rate after the 6MWT. Data were analysed using Polar Pro-Trainer 5 software (Kempele, Finland). Patients were followed for >2 years for cardiac events (hospitalisations and death).

RESULTS

Thirty-four patients had cardiac events during the 2-year follow-up period. However, there was a significant difference in the time to return to resting heart rate between the groups with and without cardiac events {with 3.6 (SD 1.1) vs without 2.8 (SD 1.1) minutes; mean difference of 0.79 (95% confidence interval (CI) of the difference 0.28 to 1.28; P=0.003}. No significant differences between patients with and without cardiac events were found for mean walking distance, mean heart rate recovery at 1minute and mean heart rate recovery at 2minutes. The receiver operating curve discriminated between patients with and without cardiac events (área under the curve 0.71, 95% CI 0.61 to 0.81; P<0.001). Using logistic regression analysis, prolonged time to return to resting heart rate (≥3minutes) independently increased the risk for cardiac events 6.9-fold (95% CI 2.34 to 20.12; P<0.001). The Kaplan-Meier curve showed more cardiac events in patients with prolonged time to return to resting heart rate (P=0.028).

CONCLUSIONS

Prolonged time to return to resting heart rate (≥3minutes) after the 6MWT was an independent predictor of cardiac events in patients with HF.

Role of confirmed and potential predictors of an unfavorable outcome in heart failure in everyday clinical practice

Heart failure (HF) is the only cardiovascular disease with an ever increasing incidence. HF, through reduced functional capacity, frequent exacerbations of disease, and repeated hospitalizations, results in poorer quality of life, decreased work productivity, and significantly increased costs of the public health system. The main challenge in the treatment of HF is the availability of reliable prognostic models that would allow patients and doctors to develop realistic expectations about the prognosis and to choose the appropriate therapy and monitoring method. At this moment, there is a lack of universal parameters or scales on the basis of which we could easily capture the moment of deterioration of HF patients’ condition. Hence, it is crucial to identify such factors which at the same time will be widely available, cheap, and easy to use. We can find many studies showing different predictors of unfavorable outcome in HF patients: thorough assessment with echocardiography imaging, exercise testing (e.g., 6-min walk test, cardiopulmonary exercise testing), and biomarkers (e.g., N-terminal pro-brain type natriuretic peptide, high-sensitivity troponin T, galectin-3, high-sensitivity C-reactive protein). Some of them are very promising, but more research is needed to create a specific panel on the basis of which we will be able to assess HF patients. At this moment despite identification of many markers of adverse outcomes, clinical decision-making in HF is still predominantly based on a few basic parameters, such as the presence of HF symptoms (NYHA class), left ventricular ejection fraction, and QRS complex duration and morphology.

Prognostic value of 6-minute walk test and cardiopulmonary exercise test in acute heart failure (from the ESCAPE trial)

Introduction

We aim to study the utility of 6-minute walk distance (6MWD) and cardiopulmonary exercise testing (CPET) in patients with acute systolic heart failure (HF) in predicting post-discharge outcomes.

Methods

The ESCAPE trial data was utilized to examine the prognostic role of 6MWD and CPET in predicting 6-month all-cause mortality and rehospitalization in acute HF.

Results

The average 6MWD recorded in 271 and 292 patients on admission and discharge was 597 and 765 ft., respectively. Compared with non-survivors, survivors had significantly higher 6MWD on admission (624 vs. 463 ft., P = 0.006) and discharge (789 vs. 636 ft., P = 0.006). Admission and discharge 6MWD had an AUC of 0.629 (P = 0.0047) and 0.628 (P = 0.0093) in predicting mortality. The combination of optimal 6MWD cutoff values of >288 ft. on admission and > 320 ft. on discharge was associated with significantly lower mortality (11.1% vs. 28.3%, OR 0.316, P = 0.002). When dividing the sample into quartiles of increasing walking distance, patients in the 1st quartile had significantly higher mortality on admission (OR 3.59, 95% CI 1.396-9.282, P = 0.008) and discharge (OR 3.66, 95% CI 1.357-9.839, P = 0.01) compared with 4th quartile. P-value for the trend in mortality across quartiles of 6MWD on admission and discharge was 0.016 and 0.047, respectively. Cox proportional hazard analysis revealed that admission (HR 0.632, 95% CI 0.449-0.890, P = 0.009) and discharge 6MWD (HR 0.657, 95% CI 0.467-0.926, P = 0.016) were independent mortality determinants after adjustment for age, creatinine, sodium, systolic blood pressure and NYHA class, all on admission. CPET-derived variables did not predict either outcomes.

Conclusion

6MWD is an independent mortality determinant in advanced systolic HF.

A Comparison of Cardiopulmonary Exercise Testing and Field Walking Tests in Community-Dwelling Older Adults With Mild-to-Moderate Alzheimer's Dementia

The purpose of this study was to investigate the relationships among peak exercise parameters on 6-min walk test, shuttle walk test, and laboratory-based cardiopulmonary exercise testing in persons with Alzheimer's dementia. This study is a cross-sectional analysis of the baseline data of 90 participants (age 77.1 [6.6] years, 43% female) from the FIT-AD trial. Cardiopulmonary exercise testing produced significantly higher peak heart rate (118.6 [17.5] vs. 106 [22.8] vs. 106 [18.8] beats/min), rating of perceived exertion (16 [2.1] vs. 12 [2.3] vs. 11 [2.1]), and systolic blood pressure (182 [23.7] vs. 156 [18.9] vs. 150 [16.9] mmHg) compared with the shuttle walk test and 6-min walk test, respectively. Peak walking distance on shuttle walk test (241.3 [127.3] m) and 6-min walk test (365.0 [107.9] m) significantly correlated with peak oxygen consumption (17.1 [4.3] ml·kg-1·min-1) on cardiopulmonary exercise testing (r = .449, p ≤ .001 and r = .435, p ≤ .001), respectively, which is considerably lower than what is seen in older adults and persons with cardiopulmonary diseases.

Building a Heart Failure Clinic: A Practical Guide from the Heart Failure Society of America

Heart failure (HF) remains a leading cause of mortality and morbidity and a primary driver of health care resource use in the United States. As such, there continues to be much interest in the development and refinement of HF clinics that manage patients with HF in a guideline-directed, technology-enabled, and coordinated approach. Optimization of resource use and maintenance of collaboration with other providers are also important themes when considering implementation of HF clinics. Through this document, the Heart Failure Society of America aims to provide a contemporary, practical guide to creating and sustaining a HF clinic. The guide discusses (1) patient care considerations for delivering guideline-directed and patient-centered care, and (2) operational considerations including development of a HF clinic business plan, setting goals, leadership support, triggers for patient referral and patient follow-up, patient population served, optimal clinic staffing models, relationships with subspecialists, and continuous quality improvement. This document was developed to empower providers and clinicians who wish to build and sustain community-based, successful HF clinics.

Reliability of the six-minute walk test in individuals with stroke: systematic review and meta-analysis

PURPOSE

The six-minute walking test (6MWT) is a simple and widely used measure of functional capacity. The aim of this systematic review is to summarize findings on reliability of 6MWT in subjects who have had a stroke.

METHODS

Two independent investigators conducted an extensive search in multidisciplinary electronic databases from inception to August 2019, and selected complete original studies on the reliability of the 6MWT used to assess individuals with stroke. Two reviewers independently extracted data and evaluated methodological quality. Outcome for meta-analysis was reliability, measured by intraclass correlation coefficient (ICC). In addition, standard error of measurement (SEM) and minimal detectable change (MDC) were recorded.

RESULTS

Of the 241 potentially relevant articles screened, 6 met inclusion criteria and 5 of them were included in meta-analysis. Combined correlation coefficient of .98 (confidence interval .98-.99) was found for test-retest reliability. Only one study investigated inter-rater and intra-rater reliability. SEM and MDC values were rarely reported.

CONCLUSIONS

The 6MWT has high test-retest reliability, when used to assess individuals with stroke. Other types of reliability and SEM and MDC need further investigations in populations with a stroke.

Utility of 6-Minute Walk Test to Predict Response to Cardiac Resynchronization Therapy in Patients With Mild Heart Failure

Clinical studies of heart failure (HF) generally utilize the 6-minute walk test (6MWT) for functional capacity (FC) assessment. However, data on the impact of cardiac resynchronization therapy (CRT) on 6MWT and its role to predict long-term outcomes in mild HF patients with CRT are lacking. We studied 1,381 subjects with mild HF enrolled in Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy with 6MWT data at baseline and 1 year. We assessed the effects of CRT-D on percent change in 6MWT at 1 year by left bundle branch block (LBBB) status, identified independent predictors of 6MWT at 1 year, and evaluated the association between changes in 6MWT and risk for HF or death. Treatment with CRT-D versus implantable cardiac defibrillator (ICD) was not associated with a significant improvement in 6MWT at 1-year in LBBB subjects (2.2 % vs 0.0%, p = 0.428, but it was associated with a deterioration in 6MWT in non-LBBB subjects (4.1% vs 0.0%, p = 0.308). Multivariate analysis showed that each 5% reduction in 6MWT was independently associated with a corresponding 3% increase in the risk of subsequent HF or death (p = 0.014). In conclusion, our findings suggest that 6MWT has limited utility to identify CRT response in mild HF subjects with LBBB. However, 6MWT showed a signal toward deterioration in mild HF subjects with non-LBBB, and this was predictive of subsequent increased risk of HF or death.

Short-Term Effect of Self-Selected Training Intensity on Ambulatory Blood Pressure in Hypertensive Older Women: A Randomized Controlled Trial

PURPOSE

To investigate the short-term effect of self-selected training intensity (SSTI) on ambulatory blood pressure (BP) in hypertensive older women.

PARTICIPANTS AND METHODS

This is a randomized, single-blind, two-arm, parallel-group controlled trial that included 40 medicated hypertensive older women (64.4±3.6 years; resting systolic 118±19 and diastolic BP 68±9 mmHg). SSTI intervention was performed three times per week, 30-50 minutes per session (n=20). The control group participated in health education meetings once per week (n=20). Ambulatory BP (primary outcome) and six-minute walking test performance (secondary outcome) were assessed at baseline and following 8 weeks of intervention. Heart rate (HR), rating of perceived exertion (RPE, 6-20), and affective valence (ie, feeling scale, -5/+5) were recorded during all SSTI sessions. Intention-to-treat and per-protocol analyses were used for data analyses.

RESULTS

Fifteen participants from the SSTI group and 17 from the control group completed the study. No differences in ambulatory BP (24-h, awake, and asleep) were observed between SSTI and control groups (intention-to-treat and per-protocol analyses; p>0.05). The SSTI group showed a greater six-minute walking test performance than the control group in the intention-to-treat and per-protocol analyses (p<0.05). The participants exercised at 52±10% of HR reserve reported an RPE of 11±1 and an affective valence of 3.4±1.1 over the 8-week period.

CONCLUSION

SSTI is a feasible approach to induce a more active lifestyle and increase health-related fitness in hypertensive older women, although it does not improve BP control over a short-term period.

PHYSICAL CAPACITY, RESPIRATORY AND PERIPHERAL MUSCLE STRENGTH IN HEART FAILURE

ABSTRACT Introduction The Glittre-ADL test is a submaximal test that involves sitting/lifting, stair climbing/descending, and weight-bearing activities, with considerable potential for use in assessing exercise intolerance in heart failure. Objectives To investigate the influence of heart failure on maximal physical (ergometric test - ET) and functional (6MWT and Glittre-ADL test) capacity, on respiratory (IPmax and EPmax) and peripheral (handgrip strength) muscle strength, and to study the correlation between the variables evaluated. Methods A prospective comparative study that assessed 44 subjects divided into two groups: G1, with 26 heart patients (20 men/6 women, 65.26 ± 8.50 years), and G2, with 18 healthy subjects paired with G1 on the basis of sex ratio, age and anthropometric characteristics (10 men/8 women, 60.72 ± 8.39 years). The comparison of categorical variables was performed using the chi-square test, while continuous variables were compared using the Student t test or Mann-Whitney test. The study of the correlation between variables was conducted using the Pearson coefficient for EPmax and handgrip strength, while the Spearman correlation coefficient was used for the others, with a statistical significance level of 5%. Results Groups were homogeneous in terms of sex ratio, age and anthropometric characteristics. G1 had a worse performance in all tests: ET (p = 0.016), Glittre-ADL (p = 0.001), 6MWT (p = 0.001), IPmax (p = 0.012), EPmax (p = 0.007) and handgrip strength (p = 0.036). There was a negative correlation between the Glittre-ADL test and 6MWT, and the Glittre-ADL test and handgrip strength in G1. Conclusion Heart failure resulted in impairment of maximal physical and functional capacity and of respiratory and peripheral muscle strength, with a negative correlation between functional capacity and handgrip strength. Level of evidence II; Prospective comparative study.

Measurement of Functional Capacity to Discriminate Clinical from Subclinical Heart Failure in Patients ≥65 Years of Age

In order to show that reduced functional capacity in subclinical heart failure portends a higher risk of clinically overt (stage C) heart failure, we obtained the Duke activity status index (DASI) and 6-minute walk distance (6MWD) in 814 patients (age 70 [interquartile range 67 to 74] years, 51% female) with nonischemic subclinical heart failure. Reduced functional capacity was defined as: (1) DASI-derived metabolic equivalents <7, (2) 6MWD <2 standard deviations below the age-based normative mean (excluding those with mobility impairment) and (3) reduced 6MWD with reclassification where DASI was discordant. Based on reduced functional capacity and left ventricular dysfunction (LVD), subjects were classified into; (1) Stage A heart failure (436 with neither LVD nor reduced functional capacity), (2) Stage A with reduced functional capacity (n = 80), (3) Stage B heart failure (182 with LVD but preserved functional capacity) and (4) early stage C heart failure (52 with LVD and reduced functional capacity). Outcome was assessed by Kaplan-Meier survival estimates and Cox proportional hazard ratios. After a median follow-up of 13 months [interquartile range 11 to 19]), 76 (9%) developed heart failure - 6% of Stage A, 10% of Stage A-reduced functional capacity, 9% of Stage B and 37% of early Stage C (p < 0.001). After adjustment (for heart failure risk score, atrial fibrillation, pulmonary disease and therapy), the hazard ratio for development of overt heart failure in early Stage C was 5.92 (95% confidence intervals 2.92 to 11.54, p < 0.001) compared with Stage A and 3.08 (95% confidence intervals 1.47 to 6.47, p = 0.003) compared with Stage B.

Prognostic Value of 6-Minute Walk Distance in Patients Undergoing Percutaneous Coronary Intervention: a Veterans Affairs Prospective Study

The 6-minute walk distance (6MWD) test is a useful prognostic tool in chronic heart failure. Its usefulness after percutaneous coronary intervention is unknown. In a prospective observational study, patients underwent a 6MWD test within 2 weeks after percutaneous coronary intervention. The primary endpoint was major adverse cardiovascular events (MACE) (death, acute coronary syndrome, and heart failure admission) at one year. Receiver operating characteristic curves and area under the curve were used to determine the 6MWD test's predictive power, and the Youden index was used to measure its effectiveness. A total of 212 patients were enrolled (98% men; mean age, 65 ± 9 yr). Major comorbidities were hypertension in 187 patients (88%), dyslipidemia in 186 (88%), and diabetes mellitus in 95 (45%). Among the 176 patients (83%) who completed the 6MWD test, the incidence of MACE at one year was 22% (acute coronary syndrome in 17%; heart failure admission in 4%; and death in 3%). The area under the curve for MACE was 0.59, and 6MWD was shorter for patients with MACE than for those without (290 vs 326 m; P=0.03). For 39 patients with previous heart failure who completed the 6MWD test, the area under the curve was 0.64 for MACE and 0.78 for heart failure admission. The 6MWD test predicted reasonably well the incidence of MACE one year after percutaneous coronary intervention. In a subgroup of patients with previous heart failure, it fared even better in predicting heart failure admission. Larger studies are needed to confirm these findings.

Associação entre consumo de oxigênio de pico e teste de caminhada de seis minutos em pacientes após cirurgia cardíaca

RESUMO Pacientes submetidos a cirurgia de revascularização do miocárdio (CRM) apresentam redução da capacidade funcional cardiorrespiratória após o procedimento. Uma avaliação adequada no período pós-operatório desses indivíduos se faz fundamental, tendo em vista uma melhor prescrição para a reabilitação cardiopulmonar fase II e retorno às atividades de vida diária. Nosso objetivo foi verificar a associação entre a distância percorrida no teste de caminhada de 6 minutos (TC6) e o consumo de oxigênio de pico (VO2 pico) obtido no teste cardiopulmonar de exercício (TCPE) em pacientes 40 dias após a CRM. Nesse estudo observacional transversal, foram incluídos pacientes submetidos a CRM. A avaliação ocorreu 40 dias após a realização da cirurgia em ambiente hospitalar. Os testes realizados foram o TCPE, o protocolo em esteira rolante e o TC6, de acordo com as normas da American Thoracic Society. Para a análise dos resultados, utilizamos o teste de correlação de Pearson. A amostra contém 39 pacientes, dos quais 28 (71,8%) são do sexo masculino, com idade média de 58 anos. Foi possível observar predominância de sedentarismo (74,4%), uso de tabaco (74,4%) e alta prevalência de hipertensão arterial sistêmica (82,1%). Nos testes realizados, a distância média percorrida no TC6 foi de 494m±70m, e no TCPE o VO2 pico médio foi de 19,5±3,6ml/kg/min. A correlação linear observada entre eles foi r=0,48; p=0,02. Concluindo, houve correlação moderada e estatisticamente significativa entre distância percorrida no TC6 e o VO2 pico em pacientes 40 dias após CRM.

Comparison of the effectiveness of partial body weight-supported treadmill exercises, robotic-assisted treadmill exercises, and anti-gravity treadmill exercises in spastic cerebral palsy

Objectives

This study aims to compare the effectiveness of the partial body weight-supported treadmill exercise (PBWSTE), robotic-assisted treadmill exercise (RATE), and anti-gravity treadmill exercise (ATE) in children with spastic cerebral palsy (CP).

Patients and methods

Between December 01, 2015 and May 01, 2016, a total of 29 children (18 males, 11 females; mean age 9.3±2.3 years; range, 6 to 14 years) with spastic CP were included in the study. The patients were randomly divided into three groups as the PBWSTE group (n=10), RATE group (n=10), and ATE group (n=9). Each group underwent a total of 20 treadmill exercise sessions for 45 min for five days a week for a total of four weeks. The patients were assessed using three-dimensional gait analysis, open-circle indirect calorimeter, six-minute walking test, and Gross Motor Functional Measurement (GMFM) scale before and after treatment and at two months of follow-up.

Results

No significant change compared to baseline was found in the walking speed on gait analysis among the groups after the treatment. There was no statistically significant difference among the groups in terms of the GFMF-D, GMFM-E and six-minute walking test (p>0.05). There was a significant improvement in the oxygen consumption in the ATE group (p>0.05) and RATE group (p>0.05), but not in the PBWSTE group (p<0.05).

Conclusion

Our study findings indicate that all three treadmill exercises have a positive impact on walking, and RATE and ATE can be used more actively in patients with spastic CP.

6-minute walking test: a useful tool in the management of heart failure patients

Reduced functional ability and exercise tolerance in patients with heart failure (HF) are associated with poor quality of life and a worse prognosis. The 6-minute walking test (6MWT) is a widely available and well-tolerated test for the assessment of the functional capacity of patients with HF. Although the cardiopulmonary exercise test (a maximal exercise test) remains the gold standard for the evaluation of exercise capacity in patients with HF, the 6MWT (submaximal exercise test) may provide reliable information about the patient’s daily activity. The current review summarizes the value of 6MWT in patients with HF and identifies its usefulness and limitations in everyday clinical practice in populations of HF. We aimed to investigate potential associations of 6MWD with other measures of functional status and determinants of 6MWD in patients with HF as well as to review its prognostic role and changes to various interventions in these patients.

Validation of the 6-min Walk Test for Predicting Peak V˙O2 in Cancer Survivors

PURPOSE

To assess the quality of the relationship between V˙O2peak estimated from patient outcomes on the 6-min walk test (6MWT) and the V˙O2peak calculated from patient outcomes on the University of Northern Colorado Cancer Rehabilitation Institute (UNCCRI) treadmill protocol.

METHODS

Cancer survivors (N = 187) completed the UNCCRI treadmill protocol and a 6MWT 1 wk apart in randomized order to obtain V˙O2peak. Values from the UNCCRI treadmill protocol were compared against four common 6MWT V˙O2peak prediction equations.

RESULTS

All four 6MWT prediction equations significantly (P < 0.001) underestimated V˙O2peak with predicted values ranging from 8.0 ± 4.1 mL·kg·min to 18.6 ± 3.1 mL·kg·min, whereas the UNCCRI treadmill protocol yielded a significantly higher value of 23.9 ± 7.6 mL·kg·min. A positive strong correlation occurred between estimated V˙O2peak derived from the UNCCRI treadmill protocol and only one of the V˙O2peak values derived from the 6MWT prediction equations (r = 0.81), and all four equations consistently underpredicted V˙O2peak.

CONCLUSIONS

These findings suggest that the 6MWT is not a valid test for predicting V˙O2peak in the cancer population due to its consistent underestimation of V˙O2peak regardless of the prediction equation. Obtaining an accurate and valid V˙O2peak value is necessary to correctly prescribe an individualized exercise rehabilitation regimen for cancer survivors. It is recommended that clinicians avoid the 6MWT and instead implement treadmill testing to volitional fatigue to quantify V˙O2peak in cancer survivors.

Two-minute walk test: Reference equations for healthy adults in China

BACKGROUND AND OBJECTIVE

Although the six-minute walk test (6MWT) is widely used as a measure of exercise capacity, it may not be applicable in some settings and populations. This issue has led to increased use of the two-minute walk test (2MWT) to assess exercise capacity. The main objective of this study is to establish reference equations for the two-minute walk distance (2MWD) in healthy Chinese adults aged 18-85 years.

METHODS

A total of 973 volunteers took part in the study. We obtained verbal consent from all participants before the test, and the study design was approved by the ethics committees of Wenzhou People's Hospital. The participants performed two 2MWTs using a standardized protocol, and the longer distance was used for further analysis. Stepwise multiple regression analysis was performed using age, height and weight as independent variables and was used to establish the reference equations for the 2MWD in the male and female groups.

RESULTS

The mean walking distance for all participants was 199.1±25.81 m. Age and height were identified as independent factors that influenced the 2MWD, and they explained 35% and 34% of the variance in distance for the male and female groups, respectively.

CONCLUSION

This study resulted in determination of reference equations for predicting the 2MWD in healthy Chinese adults. These 2MWD standards will provide useful references for medical care in some settings and populations.

Baduanjin exercise for patients with ischemic heart failure on phase-II cardiac rehabilitation (BEAR trial): study protocol for a prospective randomized controlled trial

Background

Preliminary evidence based on clinical observations suggests that meditative exercise may offer potential benefits for patients with chronic heart failure (CHF). Cardiac rehabilitation (CR), as a class-IA indication in clinical practice guidelines, has been established as an effective strategy to improve quality of life and prognosis of CHF patients. Baduanjin exercise is an important component of traditional Chinese Qigong exercises. However, its benefits for CHF have not been rigorously tested. We sought to investigate whether Baduanjin, as an adjunct to standard care, improves cardiopulmonary function, exercise tolerance, and quality of life in patients with CHF caused by coronary artery disease (CAD).

Methods/design

In this randomized controlled trial, 120 patients will be randomly allocated in a 1:1 ratio to Baduanjin exercise combined with conventional exercise of CR (Baduanjin exercise group) or conventional exercise of CR alone (conventional exercise group). In addition to conventional physical activity, participants in the Baduanjin exercise group will participate in a 45-min Baduanjin exercise training session twice a week, for 12 weeks. The primary outcome is walking distance in the 6-min Walk Test (6MWT), and the secondary outcomes are peak oxygen uptake (VO₂ peak), ventilatory anerobic threshold (VAT), The minute ventilation to carbon dioxide production relationship (VE/VCO₂ slope), left ventricular end-diastolic volume index (LVEDVi), left ventricular ejection fraction (LVEF), quality of life assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ), amino-terminal pro-brain natriuretic peptide (NT-proBNP), hs-CRP, heart rate variability (HRV), New York Heart Association (NYHA) classification, and major adverse cardiovascular events.

Discussion

This is the first trial to evaluate the effects of a Baduanjin exercise-based CR program on cardiopulmonary function and exercise tolerance in ischemic CHF patients. If successful, it will prove the value of Baduanjin exercise in improving cardiopulmonary function and exercise tolerance in patients with ischemic heart failure on phase-II CR, and may further develop a Chinese Qigong exercise-based CR framework.

Trial registration

ClinicalTrials.gov, ID: NCT03229681. Registered retrospectively on 23 July 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2759-4) contains supplementary material, which is available to authorized users.

Exploring synergistic effects of aerobic exercise and mindfulness training on cognitive function in older adults: Protocol for a pilot randomized controlled trial

INTRODUCTION

Despite increasing evidence that aerobic exercise and cognitive training improve cognitive function among patients with cognitive impairment and dementia, few studies have focused on the effect of a combination of these approaches. This study will explore whether combining aerobic training (AT) with mindfulness training (MT), an intervention promoting the moment-to-moment awareness of physical sensations, affective states, and thoughts, improves cognitive function in individuals at risk of dementia. The primary objective is to determine the feasibility and acceptability of the intervention(s). The secondary objective is to obtain estimates of effect sizes on cognitive function and on possible mediators.

METHODS AND ANALYSIS

Forty participants with at least 2 risk factors for dementia will be randomized (2 × 2 factorial design) to either AT (3 sessions/week for 12 weeks), MT (1 session/week for 8 weeks), both, or usual care. Assessments of cognitive function (attention, executive function, episodic, and working memory); physical activity (accelerometry), aerobic capacity (6-minute walk test), waist-to-hip ratio, blood pressure, social support (Multidimensional Scale of Perceived Social Support), depression (Hospital Anxiety and Depression Scale), and mindfulness (Five Facets of Mindfulness) will be conducted at baseline, end of treatment, and 6-months postbaseline. Rates of retention, attendance, and program satisfaction will be calculated for each of the 4 groups to determine the feasibility and acceptability of each intervention.

ETHICS AND DISSEMINATION

This study has full ethical approval by The Miriam Hospital Institutional Review Board and adheres to the Standard Protocol Items: Recommendations for Interventional Trials reporting recommendations. If results from this exploratory, proof-of-concept study support our hypotheses, we will conduct a large randomized controlled trial (RCT) to determine the efficacy of combined MT and AT in improving cognitive function in individuals at risk of dementia. Results from the study will be disseminated through peer-reviewed journals and conference presentations. REGISTRATION DETAILS:: http://www.clinicalstrials.gov identifier NCT03289546.

A study on nonlinear estimation of submaximal effort tolerance based on the generalized MET concept and the 6MWT in pulmonary rehabilitation

BACKGROUND

The six-minute walk test (6MWT) is considered to be a simple and inexpensive tool for the assessment of functional tolerance of submaximal effort. The aim of this work was 1) to background the nonlinear nature of the energy expenditure process due to physical activity, 2) to compare the results/scores of the submaximal treadmill exercise test and those of 6MWT in pulmonary patients and 3) to develop nonlinear mathematical models relating the two.

METHODS

The study group included patients with the COPD. All patients were subjected to a submaximal exercise test and a 6MWT. To develop an optimal mathematical solution and compare the results of the exercise test and the 6MWT, the least squares and genetic algorithms were employed to estimate parameters of polynomial expansion and piecewise linear models.

RESULTS

Mathematical analysis enabled to construct nonlinear models for estimating the MET result of submaximal exercise test based on average walk velocity (or distance) in the 6MWT.

CONCLUSIONS

Submaximal effort tolerance in COPD patients can be effectively estimated from new, rehabilitation-oriented, nonlinear models based on the generalized MET concept and the 6MWT.

Evolving Role of Exercise Testing in Contemporary Cardiac Rehabilitation

Symptom-limited (maximal) exercise testing before cardiac rehabilitation (CR) was once an unambiguous standard of care. In particular, it served as an important screen for residual ischemia and instability before initiating a progressive exercise training regimen. However, improved revascularization and therapy for coronary heart disease has led many clinicians to downplay this application of exercise testing, especially because such testing is also a potential encumbrance to CR enrollment (delaying ease and efficiency of enrollment after procedures and hospitalizations) and patient burden (eg, added costs, logistic hassle, and anxiety). Nonetheless, exercise testing has enduring value for CR, especially because it reveals dynamic physiological responses as well as ischemia, arrhythmias, and symptoms pertinent to exercise prescription and training and to overall stability and prognosis. Moreover, as indications for CR have expanded, the value of exercise testing and functional assessment is more relevant than ever in the growing population of eligible patients, including those with heart failure, valvular heart disease, and posttransplantation, especially as current patients also tend to be more clinically complex, with advanced ages, multimorbidity, frailty, and obesity. This review focuses on the appropriate use of exercise testing in the CR setting. Graded exercise tests, cardiopulmonary exercise tests, submaximal walking tests, and other functional assessments (strength, frailty) for CR are discussed.

Rational and design of a randomized, double-blind, multicenter trial to evaluate the safety and tolerability of furosemide withdrawal in stable chronic outpatients with heart failure: The ReBIC-1 trial

AIMS

Furosemide is commonly prescribed for symptom relief in heart failure (HF) patients. Although few data support the continuous use of loop diuretics in apparently euvolemic HF patients with mild symptoms, there is concern about safety of diuretic withdrawal in these patients. The ReBIC-1 trial was designed to evaluate the safety and tolerability of withdrawing furosemide in stable, euvolemic, chronic HF outpatients. This multicenter initiative is part of the Brazilian Research Network in Heart Failure (ReBIC) created to develop clinical studies in HF and composed predominantly by university tertiary care hospitals.

METHODS

The ReBIC-1 trial is currently enrolling HF patients in NYHA functional class I-II, left ventricular ejection fraction ≤45%, without a HF-related hospital admission within the last 6 months, receiving a stable dose of furosemide (40 or 80 mg per day) for at least 6 months. Eligible patients will be randomized to maintain or withdraw furosemide in a double-blinded protocol. The trial has two co-primary outcomes: (1) dyspnea assessment using a visual-analogue scale evaluated at 4 time points and (2) the proportion of patients maintained without diuretics during the follow-up period. Total sample size was calculated to be 220 patients. Enrolled patients will be followed up to 90 days after randomization, and diuretic will be restarted if clinical deterioration or signs of congestion are detected. Pre-defined sub-group analysis based on NT-proBNP levels at baseline is planned.

PERSPECTIVE

Evidence-based strategies aiming to simplify HF pharmacotherapy are needed in clinical practice. The ReBIC-1 trial will determine the safety of withdrawing furosemide in stable chronic HF patients.

Tai Chi Exercise for Patients with Chronic Heart Failure: A Meta-analysis of Randomized Controlled Trials

AIM

This meta-analysis aimed to update and evaluate evidence from randomized controlled trials of tai chi for patients with chronic heart failure.

METHOD

Both English and Chinese databases were searched from their inception to June 2, 2016 (PubMed, EMBASE, Cochrane Central Register of Controlled Trials for English publications and China Knowledge Resource Integrated, Wanfang, and Weipu databases for Chinese publication). Titles, abstracts, and full-text articles were screened against study inclusion criteria: randomized controlled trials studying tai chi intervention for patients with chronic heart failure. The meta-analysis was conducted with Revman 5.3 or STATA 12.

RESULT

Thirteen randomized controlled trials were included. Tai chi induced significant improvement in 6-min walking distance (51.01 m; 30.49-71.53; P < 0.00). Moreover, tai chi was beneficial for quality of life (-10.37 points; -14.43 to -6.32; P = 0.00), left ventricular ejection fraction (7.72%; 3.58-11.89; P = 0.003), and B-type natriuretic peptide (-1.01; -1.82 to -0.19; P = 0.02).

CONCLUSION

Despite heterogeneity and risk of bias, this meta-analysis further confirms that tai chi may be an effective cardiac rehabilitation method for patients with chronic heart failure. Larger, well-designed randomized controlled trials are needed to exclude the risk of bias.

Correlation of 6-min walk test with left ventricular function and quality of life in heart failure due to Chagas disease

OBJECTIVES

To evaluate the correlation of the total distance walked during the six-minute walk test (6MWT) with left ventricular function and quality of life in patients with Chagas Disease (ChD) complicated by heart failure.

METHODS

This is a cross-sectional study of adult patients with ChD and heart failure diagnosed based on Framingham criteria. 6MWT was performed following international guidelines. New York Heart Association functional class, brain natriuretic peptide (BNP) serum levels, echocardiographic parameters and quality of life (SF-36 and MLHFQ questionnaires) were determined and their correlation with the distance covered at the 6MWT was tested.

RESULTS

Forty adult patients (19 male; 60 ± 12 years old) with ChD and heart failure were included in this study. The mean left ventricular ejection fraction was 35 ± 12%. Only two patients (5%) ceased walking before 6 min had elapsed. There were no cardiac events during the test. The average distance covered was 337 ± 105 metres. The distance covered presented a negative correlation with BNP (r = -0.37; P = 0.02), MLHFQ quality-of-life score (r = -0.54; P = 0.002), pulmonary artery systolic pressure (r = -0.42; P = 0.02) and the degree of diastolic dysfunction (r = -0.36; P = 0.03) and mitral regurgitation (r = -0.53; P = 0.0006) and positive correlation with several domains of the SF-36 questionnaire.

CONCLUSIONS

The distance walked during the 6MWT correlates with BNP, quality of life and parameters of left ventricular diastolic function in ChD patients with heart failure. We propose this test to be adopted in endemic areas with limited resources to aid in the identification of patients who need referral for tertiary centres for further evaluation and treatment.

Randomised feasibility trial into the effects of low-frequency electrical muscle stimulation in advanced heart failure patients

OBJECTIVES

Low-frequency electrical muscle stimulation (LF-EMS) may have the potential to reduce breathlessness and increase exercise capacity in the chronic heart failure population who struggle to adhere to conventional exercise. The study's aim was to establish if a randomised controlled trial of LF-EMS was feasible.

DESIGN AND SETTING

Double blind (participants, outcome assessors), randomised study in a secondary care outpatient cardiac rehabilitation programme.

PARTICIPANTS

Patients with severe heart failure (New York Heart Association class III-IV) having left ventricular ejection fraction <40% documented by echocardiography were eligible.

INTERVENTIONS

Participants were randomised (remotely by computer) to 8 weeks (5×60 mins per week) of either LF-EMS intervention (4 Hz, continuous, n=30) or sham placebo (skin level stimulation only, n=30) of the quadriceps and hamstrings muscles. Participants used the LF-EMS straps at home and were supervised weekly OUTCOME MEASURES: Recruitment, adherence and tolerability to the intervention were measured during the trial as well as physiological outcomes (primary outcome: 6 min walk, secondary outcomes: quadriceps strength, quality of life and physical activity).

RESULTS

Sixty of 171 eligible participants (35.08%) were recruited to the trial. 12 (20%) of the 60 patients (4 LF-EMS and 8 sham) withdrew. Forty-one patients (68.3%), adhered to the protocol for at least 70% of the sessions. The physiological measures indicated no significant differences between groups in 6 min walk distance(p=0.13) and quality of life (p=0.55) although both outcomes improved more with LF-EMS.

CONCLUSION

Patients with severe heart failure can be recruited to and tolerate LF-EMS studies. A larger randomised controlled trial (RCT) in the advanced heart failure population is technically feasible, although adherence to follow-up would be challenging. The preliminary improvements in exercise capacity and quality of life were minimal and this should be considered if planning a larger trial.

TRIAL REGISTRATION NUMBER

ISRCTN16749049.