Six-Minute Walk Test for Assessing Physical Functional Capacity in Chronic Heart Failure

Effects of sacubitril/valsartan on the functional capacity of real-world patients in Italy: the REAL.IT study on heart failure with reduced ejection fraction

Background

Heart failure (HF) significantly affects the morbidity, mortality, and quality of life of patients. New therapeutic strategies aim to improve the functional capacity and quality of life of patients while controlling HF-related risks. Real-world data on both the functional and cardiopulmonary exercise capacities of patients with HF with reduced ejection fraction upon sacubitril/valsartan use are lacking.

Methods

A multicenter, retrospective, cohort study, called REAL.IT, was performed based on the data collected from the electronic medical records of nine specialized HF centers in Italy. Cardiopulmonary exercise testing was performed at baseline and after 12 months of sacubitril/valsartan therapy, monitoring carbon dioxide production (VCO2) and oxygen consumption (VO2).

Results

The functional capacities of 170 patients were evaluated. The most common comorbidities were hypertension and diabetes (i.e., 53.5 and 32.4%, respectively). At follow-up, both the VO2 peak (from 15.1 ± 3.7 ml/kg/min at baseline to 17.6 ± 4.7 ml/kg/min at follow-up, p < 0.0001) and the predicted % VO2 peak (from 55.5 ± 14.1 to 65.5 ± 16.9, p < 0.0001) significantly increased from baseline. The VO2 at the anaerobic threshold (AT-VO2) increased from 11.5 ± 2.6 to 12.5 ± 3.3 ml/kg/min (p = 0.021), and the rate ratio between the oxygen uptake and the change in work (ΔVO2/Δwork slope) improved from 9.1 ± 1.5 to 9.9 ± 1.6 ml/min/W (p < 0.0001).

Conclusions

Sacubitril/valsartan improves the cardiopulmonary capacity of patients with HFrEF in daily clinical practice in Italy.

Non-Pharmacological Interventions in Patients With Heart Failure With Reduced Ejection Fraction: A Systematic Review and Network Meta-analysis

OBJECTIVE

To determine the effectiveness of non-pharmacologic interventions and the additional benefits of their combination in patients with heart failure with reduced ejection fraction (HFrEF).

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Clinical Trials Register from the date of database inception to April 22, 2023.

STUDY SELECTION

Randomized controlled trials involving non-pharmacologic interventions conducted in patients with HFrEF were included.

DATA EXTRACTION

Data were extracted by 2 independent reviewers based on a pre-tested data extraction form. The quality of evidence was assessed using the Cochrane Risk of Bias tool and the Grading of Recommendations Assessment, Development, and Evaluation method.

DATA SYNTHESIS

A total of 82 eligible studies (4574 participants) were included. We performed a random-effects model within a Bayesian framework to calculate weighted mean differences (WMDs) and 95% credibility intervals. High or moderate certainty evidence indicated that high-intensity aerobic interval training (HIAIT) was best on improving 6-minute walk distance (6MWD; 68.55 m [36.41, 100.47]) and left ventricular ejection fraction (6.28% [3.88, 8.77]), while high-intensity aerobic continuous training (HIACT) is best on improving peak oxygen consumption (Peak VO2; 3.48 mL/kg•min [2.84, 4.12]), quality of life (QOL; -17.26 [-29.99, -7.80]), resting heart rate (-8.20 bpm [-13.32, -3.05]), and N-terminal pro-B-type natriuretic peptide (-600.96 pg/mL [-902.93, -404.52]). Moderate certainty evidence supported the effectiveness of inspiratory muscle training to improve peak oxygen consumption and functional electrical stimulation to improve QOL. Moderate-intensity aerobic continuous training (MIACT) plus moderate-intensity resistance training (MIRT) had additional benefits in Peak VO2, 6MWD, and QOL. This review did not provide a comprehensive evaluation of adverse events.

CONCLUSIONS

Both HIAIT and HIACT are the most effective single non-pharmacologic interventions for HFrEF. MIACT plus MIRT had additional benefits in improving peak oxygen consumption, 6MWD, and QOL.

Role of preexisting right ventricular remodeling in symptoms and prognosis after transcatheter tricuspid valve repair

BACKGROUND

Severe tricuspid regurgitation (TR) is associated with chronic volume overload and right ventricular remodeling (RVR). Transcatheter tricuspid valve repair (TTVr) reduces TR and can improve quality of life (QoL), but the role of preprocedural RVR on TTVr outcomes remains unclear.

AIMS

To investigate the role of RVR on outcomes after TTVr for severe TR.

METHODS

Consecutive patients undergoing TTVr (61% edge-to-edge vs. 39% direct annuloplasty) for severe TR were retrospectively compared by preexisting RVR which was defined as dilation of RV mid-level diameter (> 35 mm) according to guidelines. QoL was evaluated using NYHA class, Minnesota Living with Heart Failure Questionnaire (MLHFQ), 36-Item Short Form Health Survey (SF-36), and 6-min walking distance (6MWD) 1-month after TTVr. Mid-term mortality and heart failure (HF) hospitalization were assessed through 1 year.

RESULTS

RVR was present in 137 of 223 patients (61%). Symptoms and QoL improved equally in both groups: ≥ 1 NYHA class (57% vs. 65% of patients with vs. without RVR, respectively), 6MWD (36% vs. 34%), MLHFQ (81% vs. 69%), and SF-36 (68% vs. 65%) improvement. One-year mortality and HF hospitalization were significantly higher in patients with RVR (24% and 30%, respectively) than in patients without (8% and 13%, both p < 0.05). In multivariable analysis, RVR was independently associated with mortality (HR 2.3, 95%CI (1.0-5.0), p = 0.04) and the combined endpoint of mortality or rehospitalization (HR 2.0, 95%CI (1.1-3.8), p = 0.03).

CONCLUSIONS

TTVr was associated with significant QoL improvement after 1 month, irrespective of RVR. Despite increased mortality and rehospitalization for heart failure, TTVr in the presence of RVR still provides substantial symptomatic benefit for patients with severe TR.

Exercise therapy as a digital therapeutic for chronic disease management: consideration for clinical product development

Digital exercise therapies (DET) have the potential to bridge existing care gaps for people living with chronic conditions. Acting as either a standalone, embedded within multi-modal lifestyle therapy, or adjunct to pharmacotherapy or surgery, evidence-based DETs can favorably impact the health of a rapidly growing population. Given the nascent nature of digital therapeutics, the regulatory landscape has yet to mature. As such, in the absence of clear guidelines clinical digital product developers are responsible for ensuring the DET adheres to fundamental principles such as patient risk management and clinical effectiveness. The purpose of this narrative review paper is to discuss key considerations for clinical digital product developers who are striving to build novel digital therapeutic (DTx) solutions and thus contribute towards standardization of product development. We herein draw upon DET as an example, highlighting the need for adherence to existing clinical guidelines, human-centered design and an intervention approach that leverages the Chronic Care Model. Specific topics and recommendations related to the development of innovative and scalable products are discussed which ultimately allow for differentiation from a basic wellness tool and integration to clinical workflows. By embodying a code of ethics, clinical digital product developers can adequately address patients' needs and optimize their own future digital health technology assessments including appropriate evidence of safety and efficacy.

Anodal transcranial direct current stimulation associated with aerobic exercise on the functional and physical capacity of patients with heart failure with reduced ejection fraction: ELETRIC study protocol

BACKGROUND

The hallmark symptom of heart failure (HF) is severe exercise intolerance. Fortunately, accumulated evidence suggests that exercise programs improve physical performance, enhance autonomy in daily activities and quality of life, and reduce cardiovascular and other hospitalizations. Recently, experimental studies have explored the application of non-invasive brain stimulation techniques, especially transcranial direct current stimulation (tDCS), aiming to improve physical performance due to its ability to modulate brain functioning. The primary objective of the present study is to evaluate the effects of anodal tDCS associated with aerobic exercise on the functional capacity of patients with HF with reduced ejection fraction (HFrEF). Secondary objectives are to compare the effects of tDCS associated with aerobic exercise vs. sham-tDCS associated with aerobic exercise on cardiopulmonary exercise capacity; inflammatory cytokines; and quality of life.

METHODS

This is a two-arm, prospectively registered, randomized trial with concealed allocation, double-blind, and intention-to-treat analysis. Forty-four patients with HFrEF will be recruited. The experimental group will undertake 25-30 min aerobic exercise training associated with tDCS, for 4 weeks. The control group will undergo the same aerobic exercise training, but with sham-tDCS. The primary outcome will be functional performance by the 6-min walk test. Secondary outcomes will include cardiopulmonary exercise capacity, inflammatory cytokines, and quality of life. Outcomes will be collected by a researcher blinded to group allocation at baseline (T0) and after 4 weeks of intervention (T1).

DISCUSSION

Although previous studies have investigated the combined effect of tDCS on T3 area and physical performance and have suggested that tDCS could have reduced ratings of perceived exertion by affecting the activity of the insular cortex, and therefore increase exercise tolerance, this study is the first to evaluate the effects of the addition of anodal tDCS to aerobic exercise training for improving physical and functional performance, decreasing the perceived exertion, altering the quantification of inflammatory cytokines, and improving the subclinical values of the cardiopulmonary test in patients with HFrEF, which could result in an important advance in cardiac rehabilitation for patients with chronic HF.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (ReBEC) RBR-10w787j6. Registered on 25 April 2023. https://ensaiosclinicos.gov.br/pesquisador.

Comparison of 6-min walk test distance vs. estimated maximum oxygen consumption for predicting postoperative pulmonary complications in patients undergoing upper abdominal surgery: a prospective cohort study

OBJECTIVE

The present study aims to evaluate the predictive ability of estimated maximum oxygen consumption (e[Formula: see text]O_2max) and 6-min walk distance (6MWD) for postoperative pulmonary complications (PPCs) in adult surgical patients undergoing major upper abdominal surgery.

METHOD

This study was conducted by collecting data prospectively from a single center. The two predictive variables in the study were defined as 6MWD and e[Formula: see text]O_2max. Patients scheduled for elective major upper abdominal surgery from March 2019 to May 2021 were included. The 6MWD was measured for all patients before surgery. e[Formula: see text]O_2max was calculated using the regression model of Burr, which uses 6MWD, age, gender, weight, and resting heart rate (HR) to predict aerobic fitness. The patients were categorized into PPC and non-PPC group. The sensitivity, specificity, and optimum cutoff values for 6MWD and e[Formula: see text]O_2max were calculated to predict PPCs. The area under the receiver operating characteristic curve (AUC) of 6MWD or e[Formula: see text]O_2max was constructed and compared using the Z test. The primary outcome measure was the AUC of 6MWD and e[Formula: see text]O_2max in predicting PPCs. In addition, the net reclassification index (NRI) was calculated to assess ability of e[Formula: see text]O_2max compared with 6MWT in predicting PPCs.

RESULTS

A total of 308 patients were included 71/308 developed PPCs. Patients unable to complete the 6-min walk test (6MWT) due to contraindications or restrictions, or those taking beta-blockers, were excluded. The optimum cutoff point for 6MWD in predicting PPCs was 372.5 m with a sensitivity of 63.4% and specificity of 79.3%. The optimum cutoff point for e[Formula: see text]O_2max was 30.8 ml/kg/min with a sensitivity of 91.6% and specificity of 79.3%. The AUC for 6MWD in predicting PPCs was 0.758 (95% confidence interval (CI): 0.694-0.822), and the AUC for e[Formula: see text]O_2max was 0.912 (95%CI: 0.875-0.949). A significantly increased AUC was observed in e[Formula: see text]O_2max compared to 6MWD in predicting PPCs (P < 0.001, Z = 4.713). And compared with 6MWT, the NRI of e[Formula: see text]O_2max was 0.272 (95%CI: 0.130, 0.406).

CONCLUSION

The results suggested that e[Formula: see text]O_2max calculated from the 6MWT is a better predictor of PPCs than 6MWD in patients undergoing upper abdominal surgery and can be used as a tool to screen patients at risk of PPCs.

Assessing physical activity with the wearable cardioverter defibrillator in patients with newly diagnosed heart failure

Background

The wearable cardioverter defibrillator (WCD), (LifeVest, ZOLL, Pittsburgh, PA, USA) is a medical device designed for the temporary detection and treatment of malignant ventricular tachyarrhythmias. WCD telemonitoring features enable the evaluation of the physical activity (PhA) of the patients. We sought to assess with the WCD the PhA of patients with newly diagnosed heart failure.

Methods

We collected and analyzed the data of all patients treated with the WCD in our clinic. Patients with newly diagnosed ischemic, or non-ischemic cardiomyopathy and severely reduced ejection fraction, who were treated with the WCD for at least 28 consecutive days and had a compliance of at least 18 h the day were included.

Results

Seventy-seven patients were eligible for analysis. Thirty-seven patients suffered from ischemic and 40 from non-ischemic heart disease. The average days the WCD was carried was 77.3 ± 44.6 days and the mean wearing time was 22.8 ± 2.1 h. The patients showed significantly increased PhA measured by daily steps between the first two and the last two weeks (Mean steps in the first 2 weeks: 4,952.6 ± 3,052.7 vs. mean steps in the last 2 weeks: 6,119.6 ± 3,776.2, p-value:  < 0.001). In the end of the surveillance period an increase of the ejection fraction was observed (LVEF-before: 25.8 ± 6.6% vs. LVEF-after: 37.5 ± 10.6%, p < 0.001). Improvement of the EF did not correlate with the improvement of PhA.

Conclusion

The WCD provides useful information regarding patient PhA and may be additionally utilized for early heart failure treatment adjustment.

Functional exercise capacity in maximal and submaximal activities of individuals with polio sequelae

PURPOSE

Poliomyelitis is an infectious disease that can cause total paralysis. Furthermore, poliomyelitis survivors may develop new signs and symptoms, including muscular weakness and fatigue, years after the acute phase of the disease, i.e., post-polio syndrome (PPS). Thus, the objective was to compare the functional exercise capacity during maximal and submaximal exercises among individuals with polio sequelae (without PPS diagnosis), PPS, and a control group.

METHODS

Thirty individuals participated in three groups: a control group (CG, n = 10); a group of individuals with polio sequelae but without PPS diagnosis (PG, n = 10); and a PPS group (PPSG, n = 10). All participants underwent (i) a cardiopulmonary exercise test to determine their maximal oxygen uptake ([Formula: see text]) and (ii) a series of functional field tests (i.e., walking test, sit-to-stand test, and stair climbing test).

RESULTS

[Formula: see text]O₂max was 30% lower in PPSG than in CG and PG. Regarding functional field tests, walking and stair climbing test performances were significantly different among all groups. The PPSG sit-to-stand performance was lower than CG.

CONCLUSION

The sequelae of paralytic poliomyelitis impair functional exercise capacity obtained from maximal and submaximal tests, especially in patients with PPS. Furthermore, submaximal variables appear to be more negatively impacted than maximal variables.

The added value of remote technology in cardiac rehabilitation on physical function, anthropometrics, and quality of life: a cluster randomized controlled trial (Preprint)

BACKGROUND

Cardiovascular diseases (CVDs) cause most deaths globally and can reduce quality of life (QoL) of rehabilitees with cardiac disease. The risk factors of CVDs are physical inactivity and increased BMI. With physical activity, it is possible to prevent CVDs, improve QoL, and help maintain a healthy body mass. Current literature shows the possibilities of digitalization and advanced technology in supporting independent self-rehabilitation. However, the interpretation of the results is complicated owing to the studies' high heterogeneity. In addition, the added value of this technology has not been studied well, especially in cardiac rehabilitation.

OBJECTIVE

We aimed to examine the effectiveness of added remote technology in cardiac rehabilitation on physical function, anthropometrics, and QoL in rehabilitees with CVD compared with conventional rehabilitation.

METHODS

Rehabilitees were cluster randomized into 3 remote technology intervention groups (n=29) and 3 reference groups (n=30). The reference group received conventional cardiac rehabilitation, and the remote technology intervention group received conventional cardiac rehabilitation with added remote technology, namely, the Movendos mCoach app and Fitbit charge accelerometer. The 12 months of rehabilitation consisted of three 5-day in-rehabilitation periods in the rehabilitation center. Between these periods were two 6-month self-rehabilitation periods. Outcome measurements included the 6-minute walk test, body mass, BMI, waist circumference, and World Health Organization QoL-BREF questionnaire at baseline and at 6 and 12 months. Between-group differences were assessed using 2-tailed t tests and Mann-Whitney U test. Within-group differences were analyzed using a paired samples t test or Wilcoxon signed-rank test.

RESULTS

Overall, 59 rehabilitees aged 41 to 66 years (mean age 60, SD 6 years; n=48, 81% men) were included in the study. Decrement in waist circumference (6 months: 1.6 cm; P=.04; 12 months: 3 cm; P<.001) and increment in self-assessed QoL were greater (environmental factors: 0.5; P=.02) in the remote technology intervention group than the reference group. Both groups achieved statistically significant improvements in the 6-minute walk test in both time frames (P=.01-.03). Additionally, the remote technology intervention group achieved statistically significant changes in the environmental domain at 0-6 months (P=.03) and waist circumference at both time frames (P=.01), and reference group achieve statistically significant changes in waist circumference at 0-6 months (P=.02).

CONCLUSIONS

Remote cardiac rehabilitation added value to conventional cardiac rehabilitation in terms of waist circumference and QoL. The results were clinically small, but the findings suggest that adding remote technology to cardiac rehabilitation may increase beneficial health outcomes. There was some level of systematic error during rehabilitation intervention, and the sample size was relatively small. Therefore, care must be taken when generalizing the study results beyond the target population. To confirm assumptions of the added value of remote technology in rehabilitation interventions, more studies involving different rehabilitees with cardiac disease are required.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN61225589; https://www.isrctn.com/ISRCTN61225589.

Physical Exercise to Improve Functional Capacity: Randomized Clinical Trial in Bariatric Surgery Population

Background: Bariatric surgery is a safe and effective method to lose weight over time. However, some patients fail to achieve healthy weight losses. We aimed to determine if a moderate-intensity physical exercise intervention in patients who underwent bariatric surgery increases their functional capacity thus improving bariatric surgery results. Methods: We conducted a parallel-group non-blinded randomized controlled trial at a surgery clinic in Talca, Chile. A total of 43 participants with obesity and scheduled bariatric surgery completed the six months follow-up. A physical exercise program was conducted in exercise group participants one month after bariatric surgery. Walked distance in the six-minute walk test, BMI, Borg scale of perceptive exertion results and cardiovascular variables were evaluated. Results: Patients’ weight significantly decreased after bariatric surgery but there was no difference between the groups of study. The exercise group progressed from a base value of 550 ± 75 m walked in the six-minute walk test to a sixth-month value of 649.6 ± 68.5 m (p < 0.05), whilst the control group yielded base values of 554.4 ± 35.1 and a sixth-month walked distance of 591.1 ± 75.34 (p > 0.05). Conclusions: Physical exercise in obese patients undergoing bariatric surgery increased functional capacity independently of weight losses resulting from bariatric surgery.

Systematic Review and Meta-Analysis on the Rehabilitation Effect of Different Intensity Exercise on the Patients with Cardiovascular Diseases

Background. Cardiovascular disease is a common disease with high prevalence, disability, and mortality. Exercise therapy can improve cardiac functional reserve and life quality of patients, but the benefits of different exercise intensities for cardiovascular patients are still controversial. In this study, literature search and meta-analysis were used to explore the effect of 2 intensities of exercise on the rehabilitation effect of cardiovascular patients. Methods. We searched Embase, Wiley online library, PubMed, Science Direct, and Clinicaltrials to look for randomized controlled trial (RCT) studies of high-intensity interval training (HIIT) versus moderate continuous training (MCT). After screening the inclusion criteria for the literature and assessing the risk of bias, a software analysis was performed using the R language toolkit to obtain forest plots and funnel maps. Results. 10 articles were included in this study into the quantitative analysis, and 520 patients participated in the study; meta-analysis results showed that after HIIT intervention, the VO2 peak index of patients was higher than that of the MCT group ( $\text{MD}=1.39$ , 95% CI (0.10, 2.68), $Z=2.12$ , $P=0.0344$ ), the peak heart rate HR peak was higher than that of the MCT training ( $\text{MD}=7.71$ , 95% CI (5.12, 10.30), $Z=5.84$ , $P<0.0001$ ), the respiratory exchange rate (maximum RER) was higher than that of the MCT training ( $\text{MD}=0.02$ , 95% CI (0.00, 0.04), $Z=2.36$ , $P=0.0184$ ), and the quality of life was higher than that of the MCT training ( $\text{MD}=0.39$ , 95% CI (0.07, 0.71), $Z=2.40$ , $P=0.0165$ ). Discussion. Compared with moderate continuous training, high intensity interval training is more conducive to improve the cardiopulmonary function of cardiovascular patients and improve their physical life quality.

The optimal cutoff score of the 2-min step test and its association with physical fitness in type 2 diabetes mellitus

This study was carried out to evaluate sensitivity, specificity, and test cutoff score to predict cardiorespiratory fitness by using the 2-min step test (2MST) in patients with type 2 diabetes mellites (DM). The association of the 2MST and physical fitness tests including a 6-min walk test (6MWT), a 5 time sit-to-stand test (FTSST), and leg strength in the form of a leg performance test were also investigated. This study was cross-sectional and conducted in 100 type 2 DM patients. Patients were screened through health questionnaires, medical illness, general characteristics, and physical fitness tests; 2MST, 6MWT, FTSST, and leg strength. Blood was collected for assessment of fasting blood sugar and lipid profiles. The number of steps in the 2MST was positively correlated with the distance of the 6MWT (r=0.6995, P<0.0001) and leg strength (r=0.4292, P<0.0001). 2MST was negatively correlated with time to perform the FTSST (r=−0.405, P<0.0001). Moreover, this study established the optimal cutoff score of the 2MST at ≤61 steps with 92.24% sensitivity, and 81.36% specificity to predict cardiorespiratory fitness in type 2 DM patients. Our findings indicate that the 2MST may be used as a predictor for walking capacity, leg strength, and ability to change position from sitting to standing in type 2 DM. In addition, this result may imply that patients with type 2 DM performing the 2MST at less than 61 steps was significantly associated with decreased cardiorespiratory fitness.

Chinese expert consensus on the diagnosis and treatment of chronic heart failure in elderly patients (2021)

Heart failure is a clinical syndrome caused by ventricular insufficiency, which results in decreased activity tolerance and repeated hospitalization, seriously affecting quality of life, and it is the main cause of death in elderly people. In recent years, great progress has been made in the treatment of heart failure, but the prevalence, mortality, and readmission rate among elderly patients with heart failure remain high. Because elderly patients have multiple cardiovascular disease risk factors, coexistence of multiple diseases accompanied by multiple syndromes, multiple medications, and natural decline of body functions, the clinical diagnosis, treatment, rehabilitation, and long‐term management of these patients differ from those in other populations. To facilitate clinical practice and application of clinical geriatric medicine, especially among community physicians, experts from the Cardiovascular Group, Geriatrics Branch of the Chinese Medical Association have drafted this consensus to summarize the diagnosis and treatment regimens for elderly patients with chronic heart failure and provide guidance for its clinical diagnosis and treatment in China.

Estimation of Functional Aerobic Capacity Using the Sit-to-Stand Test in Older Adults with Heart Failure with Preserved Ejection Fraction

Background: The 6-Min Walking Test (6MWT) has been proposed to assess functional aerobic capacity in patients with heart failure, but many older adults with heart failure cannot complete it. The adequacy of the 5-repetition Sit-To-Stand (5-STS), a simpler test than 6MWT, to assess the functional aerobic capacity in older adults with heart failure has not been evaluated. Objectives: This study aimed to assess the usefulness of 5-STS in estimating maximal oxygen uptake (VO2 peak) in older adults with heart failure with preserved ejection fraction (HFpEF). Methods: A cross-sectional study was carried out. Patients 70 years and older with HFpEF were included. A bivariant Pearson correlation and subsequent multivariate linear regression analysis were used to analyze the correlations between the 5-STS and the estimated VO2 peak. Results: Seventy-six patients (80.74 (5.89) years) were recruited. The 5-STS showed a moderate and inversely correlation with the estimated VO2 peak (r = −0.555, p < 0.001). The 5-STS explained 40.4% of the variance in the estimated VO2 peak, adjusted by age, sex, and BMI. When older adults were stratified by BMI, the 5-STS explained 70% and 31.4% of the variance in the estimated VO2 peak in older adults with normal weight and overweight/obesity, respectively. Conclusions: The 5-STS may be an easy tool to assess functional aerobic capacity in older adults with HFpEF, especially for those with normal weight.

Physical Activity Capacity Assessment of Patients with Chronic Disease and the Six-Minute Walk Test: A Cross-Sectional Study

Background: This study aimed to evaluate the efficacy of the Six-Minute Walk Test (6MWT) to determine the physical activity capacities of patients with chronic disease. Methods: For this cross-sectional study, we investigated 156 patients with chronic disease and no beta-blocker treatment. They systematically performed a maximal cardiopulmonary exercise test to determine their heart rate peak (HRPeak) and maximal oxygen uptake (V’O2max). We considered two groups of patients based upon the results of the functional evaluation of exercise performance: (1) No limitation in exercise performance (V’O2max greater or equal to 80% of the theoretical reference) and (2) limited exercise performance (V’O2max less than 80% of the theoretical value). All patients also received a 6MWT on the same day as the exercise test. Results: We found 68 (43.6%) patients with normal exercise capacities and 88 (56.4%) patients with limited exercise performance. In this sample, 6MWT mean distances were 510 (87) and 506 (86) m, respectively. There were no significant differences between the two groups for distance and end-test heart rate. The correlation between matrix V’O2max measured during the maximal incremental exercise test and the 6MWT distance displayed a positive slope (r = 0.549 CI95 [0.431−0.656]—p < 0.001). Conclusion: Our results showed a moderate relationship between 6MWT and physical activity capacity for patients with chronic disease.

Prediction of peak oxygen uptake from 6-minute walk test in pulmonary hypertension

Maximal oxygen uptake (V′_O2max), assessed by cardiopulmonary exercise testing (CPET), is an important parameter for risk assessment in patients with pulmonary hypertension (PH). However, CPET may not be available for all PH patients. Thus, we aimed to test previously published predictive models of V′_O2max from the 6-min walk distance (6MWD) for their accuracy and to create a new model.

We tested four models (two by Ross et al. (2010), one by Miyamoto et al. (2000) and one by Zapico et al. (2019)). To derive a new model, data were split into a training and testing dataset (70:30) and step-wise linear regression was performed. To compare the different models, the standard error of the estimate (SEE) was calculated and the models graphically compared by Bland–Altman plots. Sensitivity and specificity for correct prediction into low-risk classification (V′_O2max >15 mL/min/kg) was calculated for all models.

A total of 276 observations were included in the analysis (194/82 training/testing dataset); 6MWD and V′_O2max were significantly correlated (r=0.65, p<0.001). Linear regression showed significant correlation of 6MWD, weight and heart rate response (HRR) with V′_O2max and the best fitting prediction equation was: V′_O2max = 1.83 + 0.031 × 6MWD (m) – 0.023 × weight (kg) – 0.015 × HRR (bpm). SEEs for the different models were 3.03, 3.22, 4.36 and 3.08 mL/min/kg for the Ross et al., Miyamoto et al., Zapico et al. models and the new model, respectively. Predicted mean V′_O2max was 16.5 mL/min/kg (versus observed 16.1 mL/min/kg).

6MWD and V′_O2max reveal good correlation in all models. However, the accuracy of all models is inadequate for clinical use. Thus, CPET and 6MWD both remain valuable risk assessment tools in the management of PH.

Although maximal oxygen uptake and the 6-min walk distance show good correlation in pulmonary hypertension, all predictive models are of inadequate accuracy for clinical use and cardiopulmonary exercise testing remains an irreplaceable toolhttps://bit.ly/33HBQFk

Inter-rater reliability and agreement of 6 Minute Walk Test and 10 Meter Walk Test at comfortable walk speed in patients with acute stroke

PURPOSE

Remediation of gait problems is a key feature of neurological physiotherapy We aimed to investigate the inter-rater reliability and agreement of the Six Minute Walk Test (6MWT) and Ten Meter Walk Test (10MWT), at comfortable walking speed, in hospitalized acute ischemic stroke patients.

METHOD

Forty acute first-time patients with brain stem or hemispheric ischemic stroke aged 67.4 ± 12.5 (SD), able to walk with or without an assistive device, were tested by one of three physiotherapists. Test-retest reliability was evaluated using a one-way random effects single measures model (1,1) absolute agreement-type Interclass Correlation Coefficient (ICC). Agreement was evaluated using the Standard Error of Measurement (SEM) and Smallest Detectable Change (SDC).

RESULTS

Both tests demonstrated good reliability; ICC_1,1 0.83 (CI 95% 0.70-0.90) (6MWT) and 0.76 (CI 95% 0.59-0.87) (10MWT). The 6MWT-SEM was 27.2 m (m) and the SDC was 75.4 m. The 10MWT-SEM was 0.36 meters per second (m/s) and the SDC was 1.0 m/s.

CONCLUSION

Both tests demonstrated good inter-rater reliability, confirming their discriminative ability on a group of hospitalized first-time acute ischemic stroke patients. However, the measurement error was large for both tests, which is likely due to spontaneous neurological recovery and stress in the acute phase severely affecting the individual-level agreement estimate.

The Efficacy and Safety of Sacubitril/Valsartan in Heart Failure Patients: A Review

Heart failure (HF) is one of the leading causes of morbidity and mortality worldwide. Sacubitril/valsartan, an angiotensin receptor-neprilysin inhibitor, has been approved for the treatment of HF. At present, there have been few systematic and detailed reviews discussing the efficacy and safety of sacubitril/valsartan in HF. In this review, we first introduced the pharmacological mechanisms of sacubitril/valsartan, including the reduction in the degradation of natriuretic peptides in the natriuretic peptide system and inhibition of the renin-angiotensin system. Then, we summarized the efficacy of sacubitril/valsartan in HF patients with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF) including the reduction in risks of mortality and hospitalization, reversal of cardiac remodeling, regulation of biomarkers of HF, improvement of the quality of life, antiarrhythmia, improving renal dysfunction and regulation of metabolism. Finally, we discussed the safety and tolerability of sacubitril/valsartan in the treatment of HFrEF or HFpEF. Compared with ACEIs/ARBs or placebo, sacubitril/valsartan showed good safety and tolerability, although the risk of hypotension might be high. In conclusion, the overwhelming majority of studies show that sacubitril/valsartan is effective and safe in the treatment of HFrEF patients but that it has little benefit in HFpEF patients. Sacubitril/valsartan will probably be a promising anti-HF drug in the near future.

Predicting mortality in non-cystic fibrosis bronchiectasis patients using distance-saturation product

BACKGROUND

The bronchiectasis severity index (BSI) and FACED score are currently used in predicting outcomes of non-cystic fibrosis bronchiectasis (NCFB). Distance-saturation product (DSP), the product of distance walked, and lowest oxygen saturation during the 6-min walk test showed strong predictive power of mortality in non-CF bronchiectasis patients. This study aimed to compare the efficacy of these scores and DSP in predicting mortality.

METHODS AND PATIENTS

Our retrospective study included NCFB patients from January 2004 to December 2017. We recorded the basic data, pulmonary function, radiologic studies, sputum culture results, acute exacerbations (AE), emergency department (ED) visits, hospitalization, and mortality.

RESULTS

A total 130 NCFB patients were analysed. The mean BSI score, FACED score, and DSP were 8.8 ± 4.9, 3.4 ± 1.7, and 413.1 ± 101.5 m%, respectively. BSI and FACED scores had comparable predictive power for AE (p=.011; p=.010, respectively). The BSI score demonstrated a significant correlation with ED visits (p=.0003). There were 12 deaths. Patients were stratified using a DSP cut-off value of 345 m% according to the best area under receiver operator characteristic curve (AUC) value in mortality. DSP was not correlated with AE and ED visits. BSI, FACED scores, and DSP demonstrated statistically significant correlations with hospitalization (p<.0001; p<.0001; p=.0007, respectively). The AUC for overall mortality was similar for BSI, FACED score, and DSP (0.80 versus 0.85, p=.491; 0.85 versus 0.83, p=.831).

CONCLUSION

DSP had comparable predictive power for mortality as the well-validated BSI and FACED scores and is relatively easy to use in clinical practice.KEY MESSAGEDistance-saturation product (DSP) comprised with the product of distance walked, and lowest oxygen saturation during the 6-min walk test, which is common used in clinical practice.DSP demonstrated strong and comparable predictive power of mortality as the well-validated BSI and FACED scores in non-CF bronchiectasis patients.

Effects of Cardiac Rehabilitation Training in Patients with Heart Failure Based on Traditional Chinese Exercise: A Systematic Review and Meta-Analysis

Methods

PubMed, Embase, Cochrane Library, and three Chinese databases, namely, China National Knowledge Network, Wanfang, and China Biomedical Network, were searched from the time of their inceptions through August, 2021. We retrieved the studies on the application of TCE-based cardiac rehabilitation in patients with HF. Based on the standard evaluation methods of Cochrane Reviewer's Handbook 5.1.0, two authors independently assessed the risk of bias and evaluated the methodological quality of the studies included. The RevMan 5.3 software was used for further meta-analysis. Additionally, the GRADEpro GDT web version was used to assess the quality of the evidence in these studies.

Results

Nine randomized controlled trials involving 721 patients were included in this analysis. The meta-analysis revealed that the TCE (experimental group) effectively improved the patient's motor function and endurance compared to walking or other activities (control group) (mean difference, MD = 68.23, 95% CI [54.55, 81.91]; P < 0.00001). From each subgroup analysis, the exercising ability of the experimental group was higher than that of the control group. The quality of life's score in the experimental group was lower than that of the control group (MD = −9.51, 95%CI [−17.84, −1.18]; P=0.03). The plasma B-type natriuretic peptide content in the experimental group was lower than that in the control group (MD = −59.77, 95%CI [−82.85, −36.7]; P < 0.00001). The number of hospitalizations (MD = −0.83, 95%CI [−0.98, −0.68]; P < 0.00001) and hospital costs in the experimental group (MD = −1.6, 95%CI [−1.89, −1.31]; P < 0.00001) were lower than those in the control group. However, no significant differences were observed in the left ventricular ejection fraction and maximal oxygen consumption between the two groups (MD = 1.38, 95%CI [−3.08, 5.84] and P=0.54; MD = −0.04, 95%CI [−1.62, 1.54] and P=0.96, respectively). From the current analysis, TCE can be considered a relatively safe exercise method. According to the GRADE evaluation results on the evidence level, the studies included were of moderate quality, low quality, or very low quality.

Conclusions

Our systematic review showed that TCE had potential benefits in improving patients' cardiac function, motor function, and quality of life. Therefore, TCE might be an effective adjuvant therapy in patients with HF. However, given the inclusion of the low-quality elucidations, further rigorous studies are urgently needed to confirm these results.

Wearable Cardioverter-Defibrillator-Measured Step Count for the Surveillance of Physical Fitness during Cardiac Rehabilitation

Background: The wearable cardioverter–defibrillator (WCD) has a built-in accelerometer, which allows tracking of patients’ physical activity by remote monitoring. It is unclear whether WCD-measured physical activity, step count, and heart rate correlate with established tools for the assessment of cardiopulmonary fitness such as the 6-min walk test (6MWT). Objective: To correlate measurements of patient physical activity through the WCD with a supervised 6MWT during in-patient cardiac rehabilitation (CR) and to allow their use as surrogate parameters of cardiopulmonary fitness in an out-patient setting. Methods: Consecutive patients with a history of WCD use treated at our center and an in-patient CR following an index hospitalization were included. Baseline characteristics, measurements of WCD accelerometer (median daily step count, median daily activity level), median daily heart rate, and clinically supervised 6MWT at admission and discharge of CR were obtained. Results: Forty-one patients with a mean age of 55.5 (±11.5) years were included. Thirty-five patients (85.4%) were male and 28 patients (68%) had a primary prophylactic WCD-indication. The most common underlying heart diseases were ischemic heart disease (24 patients 58.6%) and dilated cardiomyopathy (13 patients, 31.7%). Median CR duration was 20 (IQR 19.75–26.25) days. 6MWT distance increased from a mean of 329 m (±107) to 470 m (±116) during CR (p < 0.0001). The median daily step count and activity level increased significantly, from 5542 steps (IQR 3718–7055) to 8778 (IQR 6229–12,920, p < 0.0001) and median 117 × 10⁶ (IQR 96 × 10⁶–142 × 10⁶) threshold value exceedance (TVE) to 146 × 10⁶ TVE (IQR 110 × 10⁶–169 × 10⁶, p < 0.0001), respectively. The median heart rate was 74.9 bpm (IQR 65.8–84.5) and 70.2 (IQR 64.1–77.3, p = 0.09) at admission and discharge, respectively. Of all three parameters, median daily step count showed the best correlation to the results of the 6MWT at admission and discharge (r = 0.32, p = 0.04 and 0.37, p = 0.02, respectively). Conclusions: Remote monitoring of median daily step count as assessed by the WCD’s accelerometer showed positive correlation with the 6MWT and could serve as a surrogate for cardiopulmonary exercise capacity. Assessment of daily step count and activity level measured remotely by the WCD could help to tailor optimal exercise instruction for patients not attending CR.

The 6-Minute Walk Test predicts long-term physical improvement among intensive care unit survivors: a prospective cohort study

Objetivo

Avaliar a capacidade do Teste de Caminhada de 6 Minutos para predizer a melhora do estado funcional físico em longo prazo de pacientes sobreviventes à unidade de terapia intensiva.

Métodos

Foram avaliados, de forma prospectiva, entre fevereiro de 2017 e agosto de 2018, em um ambulatório pós-unidade de terapia intensiva, 32 sobreviventes à unidade de terapia intensiva. Foram inscritos consecutivamente os pacientes com permanência na unidade de terapia intensiva acima de 72 horas (para admissões emergenciais) ou acima de 120 horas (para admissões eletivas) que compareceram ao ambulatório pós-unidade de terapia intensiva 4 meses após receberem alta da unidade de terapia intensiva. A associação entre a distância percorrida no Teste de Caminhada de 6 Minutos realizado na avaliação inicial e a evolução do estado funcional físico foi avaliada durante 8 meses, com utilização do Índice de Barthel.

Resultados

A distância média percorrida no Teste de Caminhada de 6 Minutos foi significantemente mais baixa nos sobreviventes à unidade de terapia intensiva do que na população geral (405m versus 557m; p < 0,001). A idade (β = -4,0; p < 0,001) e a fraqueza muscular (β = -99,7; p = 0,02) se associaram com a distância percorrida no Teste de Caminhada de 6 Minutos. A distância percorrida no Teste de Caminhada de 6 Minutos se associou com melhora do estado funcional físico no período de 8 meses de acompanhamento desses pacientes (razão de chance para cada 10m: 1,07; IC95% 1,01 - 1,16; p = 0,03). A área sob a curva Característica de Operação do Receptor para predição da melhora funcional física pelo Teste de Caminhada de 6 Minutos foi de 0,72 (IC95% 0,53 - 0,88).

Conclusão

O Teste de Caminhada de 6 Minutos, realizado 4 meses após a alta da unidade de terapia intensiva, predisse com precisão moderada a melhora do estado funcional físico de sobreviventes à unidade de terapia intensiva.

Wearable Cardioverter Defibrillator-Guided 6-Min Walk Test Performed at Home Is Accurate and Reliable: RESULTS OF THE TRENDS STUDY

PURPOSE

The 6-min walk test (6MWT) is broadly used to evaluate the functional ability of patients with heart failure (HF). The purpose of this study was to evaluate the accuracy and reliability of the wearable cardioverter defibrillator (WCD)-guided 6MWT performed at home by patients with HF versus in-clinic testing.

METHODS

Patients (n = 197) with HF and a low ejection fraction prescribed a WCD were randomized to 2 groups. Group 1 completed an in-clinic clinician-guided 6MWT while wearing the WCD; results were recorded by the clinician. Group 2 completed a WCD-guided 6MWT, also performed in the clinic; results were recorded by the WCD accelerometer. Both groups performed weekly unsupervised WCD-guided 6MWTs at home, with results recorded by the WCD.

RESULTS

The initial in-clinic 6MWT showed no significant group difference in distance walked (group 1 = 306 m; group 2 = 297 m). For patients in group 2 who completed at least one 6MWT at home, there was a 15-step decrease between the in-clinic WCD-guided 6MWT and the first at-home 6MWT, 558 and 543 median steps (P = .001), respectively. Among patients with at least 8 weekly home WCD-guided 6MWTs (n = 70), there was no significant difference in the number of steps walked during the 6MWT from week to week.

CONCLUSIONS

Results of the in-clinic 6MWT are similar between clinician-guided and WCD-guided patients across objective distances. Distances walked with a WCD-guided walk test were consistent whether conducted in the clinic or at home and were reliable over time.

Mobile Health Intervention Promoting Physical Activity in Adults Post Cardiac Rehabilitation: Pilot Randomized Controlled Trial

Background

Cardiac rehabilitation (CR) is an exercise-based program prescribed after cardiac events associated with improved physical, mental, and social functioning; however, many patients return to a sedentary lifestyle leading to deteriorating functional capacity after discharge from CR. Physical activity (PA) is critical to avoid recurrence of cardiac events and mortality and maintain functional capacity. Leveraging mobile health (mHealth) strategies to increase adherence to PA is a promising approach. Based on the social cognitive theory, we sought to determine whether mHealth strategies (Movn mobile app for self-monitoring, supportive push-through messages, and wearable activity tracker) would improve PA and functional capacity over 2 months.

Objective

The objectives of this pilot randomized controlled trial were to examine preliminary effects of an mHealth intervention on group differences in PA and functional capacity and group differences in depression and self-efficacy to maintain exercise after CR.

Methods

During the final week of outpatient CR, patients were randomized 1:1 to the intervention group or usual care. The intervention group downloaded the Movn mobile app, received supportive push-through messages on motivation and educational messages related to cardiovascular disease (CVD) management 3 times per week, and wore a Charge 2 (Fitbit Inc) activity tracker to track step counts. Participants in the usual care group wore a pedometer and recorded their daily steps in a diary. Data from the 6-minute walk test (6MWT) and self-reported questionnaires were collected at baseline and 2 months.

Results

We recruited 60 patients from 2 CR sites at a community hospital in Northern California. The mean age was 68.0 (SD 9.3) years, and 23% (14/60) were female; retention rate was 85% (51/60). Our results from 51 patients who completed follow-up showed the intervention group had a statistically significant higher mean daily step count compared with the control (8860 vs 6633; P=.02). There was no difference between groups for the 6MWT, depression, or self-efficacy to maintain exercise.

Conclusions

This intervention addresses a major public health initiative to examine the potential for mobile health strategies to promote PA in patients with CVD. Our technology-based pilot mHealth intervention provides promising results on a pragmatic and contemporary approach to promote PA by increasing daily step counts after completing CR.

Trial Registration

ClinicalTrials.gov NCT03446313; https://clinicaltrials.gov/ct2/show/NCT03446313

Activity data from wearables as an indicator of functional capacity in patients with cardiovascular disease

Background

Smartphone and wearable-based activity data provide an opportunity to remotely monitor functional capacity in patients. In this study, we assessed the ability of a home-based 6-minute walk test (6MWT) as well as passively collected activity data to supplement or even replace the in-clinic 6MWTs in patients with cardiovascular disease.

Methods

We enrolled 110 participants who were scheduled for vascular or cardiac procedures. Each participant was supplied with an iPhone and an Apple Watch running the VascTrac research app and was followed for 6 months. Supervised 6MWTs were performed during clinic visits at scheduled intervals. Weekly at-home 6MWTs were performed via the VascTrac app. The app passively collected activity data such as daily step counts. Logistic regression with forward feature selection was used to assess at-home 6MWT and passive data as predictors for “frailty” as measured by the gold-standard supervised 6MWT. Frailty was defined as walking <300m on an in-clinic 6MWT.

Results

Under a supervised in-clinic setting, the smartphone and Apple Watch with the VascTrac app were able to accurately assess ‘frailty’ with sensitivity of 90% and specificity of 85%. Outside the clinic in an unsupervised setting, the home-based 6MWT is 83% sensitive and 60% specific in assessing “frailty.” Passive data collected at home were nearly as accurate at predicting frailty on a clinic-based 6MWT as was a home-based 6MWT, with area under curve (AUC) of 0.643 and 0.704, respectively.

Conclusions

In this longitudinal observational study, passive activity data acquired by an iPhone and Apple Watch were an accurate predictor of in-clinic 6MWT performance. This finding suggests that frailty and functional capacity could be monitored and evaluated remotely in patients with cardiovascular disease, enabling safer and higher resolution monitoring of patients.

Correlation between functional capacity and oxidative stress and inflammation in hemodialysis patients

INTRODUCTION

Patients with chronic kidney disease (CKD) may present impaired functional capacity due to peripheral muscle involvement. Oxidative stress and inflammation are probably involved in this pathophysiology. This study aimed to evaluate the association between functional capacity and biomarkers of oxidative stress as well as biomarkers of inflammation in patients under chronic hemodialysis therapy.

METHOD

Cross-sectional study including 41 patients from a single hemodialysis center. Functional capacity was assessed through the 6-min walk test (6MWT). The assessed blood biomarkers were: malondialdehyde (MDA) (oxidative stress, TBARS method) and angiopoietin-2 (Ang-2) (inflammation, ELISA). The influence of gender on impairment of functional capacity was further explored.

RESULTS

There was an inversely proportional correlation between the 6MWD and MDA (r = -,322 and p = 0.040) and Ang-2 (r = -, 376 and p = 0.016) values. 6MWD was 370.9 ± 101.2 m and 391.4 ± 108.2 m in women and men, respectively (p < 0.001), which means 29.3% and 34.3% reduction of the expected values for healthy individuals from the same age range.

CONCLUSION

Patients with CKD under hemodialysis, regardless of gender, presented impaired performance in 6MWT and this impairment was associated with oxidative stress and inflammation.

Physical functional performance and prognosis in patients with heart failure: a systematic review and meta-analysis

Background

Patients with Heart Failure (HF) show impaired functional capacities which have been related to their prognosis. Moreover, physical functional performance in functional tests has also been related to the prognosis in patients with HF. Thus, it would be useful to investigate how physical functional performance in functional tests could determine the prognosis in patients with HF, because HF is the leading cause of hospital admissions for people older than 65 years old. This systematic review and meta-analysis aims to summarise and synthesise the evidence published about the relationship between physical functional performance and prognosis in patients with HF, as well as assess the risk of bias of included studies and the level of evidence per outcome.

Methods

Major electronic databases, such as PubMed, AMED, CINAHL, EMBASE, PEDro, Web of Science, were searched from inception to March 2020 for observational longitudinal cohort studies (prospective or retrospective) examining the relationship between physical functional performance and prognosis in patients with HF.

Results

44 observational longitudinal cohort studies with a total of 22,598 patients with HF were included. 26 included studies reported a low risk of bias, and 17 included studies showed a moderate risk of bias. Patients with poor physical functional performance in the Six Minute Walking Test (6MWT), in the Short Physical Performance Battery (SPPB) and in the Gait Speed Test showed worse prognosis in terms of larger risk of hospitalisation or mortality than patients with good physical functional performance. However, there was a lack of homogeneity regarding which cut-off points should be used to stratify patients with poor physical functional performance from patients with good physical functional performance.

Conclusion

The review includes a large number of studies which show a strong relationship between physical functional performance and prognosis in patients with HF. Most of the included studies reported a low risk of bias, and GRADE criteria showed a low and a moderate level of evidence per outcome.

Impact of sacubitril/valsartan treatment on depression and anxiety in heart failure with reduced ejection fraction

Background: In patients with heart failure (HF), depression and anxiety disorders are common and associated with adverse outcomes. Sacubitril/valsartan, which is an angiotensin receptor neprilysin inhibitor (ARNI), has been shown to reduce mortality and hospitalisation in patients with heart failure with reduced ejection fraction (HFrEF). However, its effects on depression and anxiety levels remain unclear.Methods: Sacubitril/valsartan was initiated in 115 symptomatic patients with HFrEF receiving an optimal medical treatment with angiotensin inhibition. Patients underwent 6-minute walk test (6-MWT), The Beck Depression Inventory-II (BDI-II) and Beck Anxiety Inventory (BAI) were administered at the switching to ARNI and at the third-month follow-up of the maximum sacubitril/valsartan dose.Results: A significant improvement was observed in BDI-II and BAI scores when compared before and after the sacubitril/valsartan treatment (13.7 ± 9.7 to 7.6 ± 3.8, p < 0.001 and 13.3 ± 8.9 to 8.1 ± 4.1, p < 0.001, respectively). The 6-MWT distance significantly increased from 213 ± 95 to 327 ± 118 mt (p < 0.001). Overall, the patients exhibited a significant functional improvement following the initiation of sacubitril/valsartan: 27% of the patients improved by two New York Heart Association (NYHA) classes, 52% improved by one NYHA functional class, and 31% remained stable.Conclusion: In patients with HFrEF, the switch from angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker therapy to sacubitril/valsartan resulted in a significant improvement in both depression, anxiety symptoms and functional statuses.

Leveraging Walking Performance to Understand Work Fatigue Among Young Adults: Mixed-Methods Study

Background

Work fatigue negatively impacts personal health in the long term. Prior research has indicated the possibility of leveraging both walking parameters and perceptual measures to assess a person’s fatigue status. However, an effective and ubiquitous approach to assessing work fatigue in young adults remains unexplored.

Objective

The goals of this paper were to (1) explore how walking rhythms and multiple streams of data, including reaction time, self-reports, and an activity diary, reflect work-induced fatigue in the lab setting; (2) identify the relationship between objective performance and subjective perception in indicating fatigue status and fatigability; and (3) propose a mobile-based assessment for work-induced fatigue that uses multiple measurements.

Methods

We conducted a 2-day in-lab study to measure participants’ fatigue status using multiple measurements, including the stair climb test (SCT), the 6-minute walk test (6MWT), and the reaction time test. Both the SCT and the 6MWT were conducted at different points in time and under 2 conditions (measurement time, including prior to and after work, and pace, including normal and fast). Participants reported their fatigue perception through questionnaires completed before conducting walking tests and in an activity diary recorded over a week. Walking performance data were collected by a smartphone with a built-in 3-axis accelerometer. To examine the effect of fatigability on walking performance, we first clustered participants into 2 groups based on their reported mental fatigue level in the entry surveys and then compared their walking performance using a generalized linear model (GLM). The reaction time was examined using a 2-way repeated-measures GLM. We conducted semistructured interviews to understand participants’ fatigue perception after each day’s walking tests.

Results

All participants (N=26; mean age 24.68 years) were divided into 2 groups—the fatigue-sensitive group (11/26, 42%) and the fatigue-nonsensitive group (15/26, 58%)—based on their mental subscores from 3 entry surveys: Fatigue Scale-14, Three-Dimensional Work Fatigue Inventory, and Fatigue Self-Assessment Scale (FSAS). The fatigue-sensitive group reported a significantly higher FSAS score in the before-work setting (t₅₀=–3.361; P=.001). The fatigue-sensitive group covered fewer steps than the fatigue-nonsensitive group (β₁=–0.099; SE 0.019; t₁=–5.323; P<.001) and had a higher step-to-step time variability in the 6MWT (β₁=9.61 × 10^–4; t₁=2.329; P=.02). No strong correlation between subjective and objective measurements was observed in the study.

Conclusions

Walking parameters, including step counts and step-to-step time variability, and some selected scales (eg, FSAS) were found to reflect participants’ work-induced fatigue. Overall, our work suggests the opportunity of employing mobile-based walking measurements to indicate work fatigue among young adults.

Factors Associated with Exercise-Induced Desaturation in Patients with Chronic Obstructive Pulmonary Disease

Purpose

The 6-min walk test (6MWT) is a useful tool to assess the physiologic function in patients with chronic obstructive pulmonary disease (COPD). The recent study showed that patients with COPD with oxygen desaturation during the 6MWT had an increased risk of exacerbation and death compared with those without oxygen desaturation. This study aimed to explore the potential risk factors for exercise-induced desaturation (EID) in patients with COPD.

Patients and Methods

Adult patients with COPD were enrolled from the Chang Gung Research Database between January 2013 and January 2017. Age, sex, body mass index, underlying diseases, medications, and results of the pulmonary function tests and 6MWT were retrospectively collected and analyzed.

Results

Among 1768 patients with COPD, 932 (52.7%) had oxygen desaturation, and the other 836 (47.3%) had no desaturation during the 6MWT. The patients with EID had a shorter 6-min walk distance than those without desaturation (352.08±120.29 vs 426.56±112.56, p<0.0001). In the multivariate logistic regression analysis, older age, female sex, lower forced expiratory volume in 1 s, and comorbidity with atrial fibrillation (AF) were associated with oxygen desaturation during the 6MWT. Patients with EID had higher exacerbation frequency than those without desaturation in the 1-year follow-up period (0.59±1.50 vs 0.34±1.26, p<0.0001). Patients with COPD with AF also had a higher rate of exacerbation requiring emergency department visit or hospitalization in the 1-year follow-up.

Conclusion

This study demonstrates that older age, low FEV1, and female sex are risk factors for EID. Desaturation during 6MWT is related to frequent acute exacerbation of COPD in the 1-year follow-up.

Short-Term Exercise Progression of Cardiovascular Patients throughout Cardiac Rehabilitation: An Observational Study

Cardiac rehabilitation (CR) is a highly recommended secondary prevention measure for patients with diagnosed cardiovascular disease. Unfortunately, participation rates are low due to enrollment and adherence issues. As such, new CR delivery strategies are of interest, as to improve overall CR delivery. The goal of the study was to obtain a better understanding of the short-term progression of functional capacity throughout multidisciplinary CR, measured as the change in walking distance between baseline six-minute walking test (6MWT) and four consecutive follow-up tests. One-hundred-and-twenty-nine patients diagnosed with cardiovascular disease participated in the study, of which 89 patients who completed the whole study protocol were included in the statistical analysis. A one-way repeated measures ANOVA was conducted to determine whether there was a significant change in mean 6MWT distance (6MWD) throughout CR. A three-way-mixed ANOVA was performed to determine the influence of categorical variables on the progression in 6MWD between groups. Significant differences in mean 6MWD between consecutive measurements were observed. Two subgroups were identified based on the change in distance between baseline and end-of-study. Patients who increased most showed a linear progression. In the other group progression leveled off halfway through rehabilitation. Moreover, the improvement during the initial phase of CR seemed to be indicative for overall progression. The current study adds to the understanding of the short-term progression in exercise capacity of patients diagnosed with cardiovascular disease throughout a CR program. The results are not only of interest for CR in general, but could be particularly relevant in the setting of home-based CR.

Exercise-based cardiac rehabilitation for chronic heart failure: the EXTRAMATCH II individual participant data meta-analysis

BACKGROUND

Current national and international guidelines on the management of heart failure (HF) recommend exercise-based cardiac rehabilitation (ExCR), but do not differentiate this recommendation according to patient subgroups.

OBJECTIVES

(1) To obtain definitive estimates of the impact of ExCR interventions compared with no exercise intervention (control) on mortality, hospitalisation, exercise capacity and health-related quality of life (HRQoL) in HF patients; (2) to determine the differential (subgroup) effects of ExCR in HF patients according to their age, sex, left ventricular ejection fraction, HF aetiology, New York Heart Association class and baseline exercise capacity; and (3) to assess whether or not the change in exercise capacity mediates for the impact of the ExCR on final outcomes (mortality, hospitalisation and HRQoL), and determine if this is an acceptable surrogate end point.

DESIGN

This was an individual participant data (IPD) meta-analysis.

SETTING

An international literature review.

PARTICIPANTS

HF patients in randomised controlled trials (RCTs) of ExCR.

INTERVENTIONS

ExCR for at least 3 weeks compared with a no-exercise control, with 6 months' follow-up.

MAIN OUTCOME MEASURES

All-cause and HF-specific mortality, all-cause and HF-specific hospitalisation, exercise capacity and HRQoL.

DATA SOURCES

IPD from eligible RCTs.

REVIEW METHODS

RCTs from the Exercise Training Meta-Analysis of Trials for Chronic Heart Failure (ExTraMATCH/ExTraMATCH II) IPD meta-analysis and a 2014 Cochrane systematic review of ExCR (Taylor RS, Sagar VA, Davies EJ, Briscoe S, Coats AJ, Dalal H, et al. Exercise-based rehabilitation for heart failure. Cochrane Database Syst Rev 2014;4:CD003331).

RESULTS

Out of the 23 eligible RCTs (4398 patients), 19 RCTs (3990 patients) contributed data to this IPD meta-analysis. There was a wide variation in exercise programme prescriptions across included studies. Compared with control, there was no statistically significant difference in pooled time-to-event estimates in favour of ExCR, although confidence intervals (CIs) were wide: all-cause mortality had a hazard ratio (HR) of 0.83 (95% CI 0.67 to 1.04); HF-related mortality had a HR of 0.84 (95% CI 0.49 to 1.46); all-cause hospitalisation had a HR of 0.90 (95% CI 0.76 to 1.06); and HF-related hospitalisation had a HR of 0.98 (95% CI 0.72 to 1.35). There was a statistically significant difference in favour of ExCR for exercise capacity and HRQoL. Compared with the control, improvements were seen in the 6-minute walk test (6MWT) (mean 21.0 m, 95% CI 1.57 to 40.4 m) and Minnesota Living with Heart Failure Questionnaire score (mean -5.94, 95% CI -1.0 to -10.9; lower scores indicate improved HRQoL) at 12 months' follow-up. No strong evidence for differential intervention effects across patient characteristics was found for any outcomes. Moderate to good levels of correlation (R ² _trial > 50% and p > 0.50) between peak oxygen uptake (VO₂peak) or the 6MWT with mortality and HRQoL were seen. The estimated surrogate threshold effect was an increase of 1.6 to 4.6 ml/kg/minute for VO₂peak.

LIMITATIONS

There was a lack of consistency in how included RCTs defined and collected the outcomes: it was not possible to obtain IPD from all includable trials for all outcomes and patient-level data on exercise adherence was not sought.

CONCLUSIONS

In comparison with the no-exercise control, participation in ExCR improved the exercise and HRQoL in HF patients, but appeared to have no effect on their mortality or hospitalisation. No strong evidence was found of differential intervention effects of ExCR across patient characteristics. VO₂peak and 6MWT may be suitable surrogate end points for the treatment effect of ExCR on mortality and HRQoL in HF. Future studies should aim to achieve a consensus on the definition of outcomes and promote reporting of a core set of HF data. The research team also seeks to extend current policies to encourage study authors to allow access to RCT data for the purpose of meta-analysis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014007170.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Fick principle and exercise pulmonary hemodynamic determinants of the six-minute walk distance in pulmonary hypertension

The six-minute walk test is widely used to assess the severity and prognosis of pulmonary hypertension. However, the pathophysiology underlying a compromised six-minute walk distance is incompletely characterized. The purpose of this study is to evaluate the Fick principle and pulmonary hemodynamic determinants of the six-minute walk distance in patients with suspected pulmonary hypertension. Twenty-nine patients were retrospectively studied and underwent a right heart catheterization for the evaluation of suspected pulmonary hypertension. With the pulmonary artery catheter in place, patients were moved to a treadmill and completed a six-minute walk test. Fick cardiac output and indices of right heart afterload were calculated using continuous measurements of pulmonary vascular pressures, gas exchange, and mixed venous blood samples. Fifteen subjects who walked ≤ 348 m were compared to 14 subjects who walked > 348 m. Systemic oxygen delivery was impaired in six-minute walk distance ≤ 348 m compared to six-minute walk distance > 348 m (15.2 ± 6.2 vs. 23.2 ± 6.8 mL/kg/min, p < 0.01). Impaired oxygen delivery was due to a depressed cardiac index and decreased cardiac reserve demonstrated by the change in the stroke volume index (3.0 ± 14 vs. 17 ± 15 mL/min/m², p = 0.02). The six-minute walk distance positively correlated with oxygen delivery (r = 0.501, p = 0.006) and inversely correlated with oxygen extraction (r = 0.369, p = 0.049). A decreased six-minute walk distance was associated with an increased total pulmonary resistance (r = 0.502, p = 0.006) and pulmonary vascular resistance (r = 0.530, p = 0.003). In patients with suspected pulmonary hypertension, a decreased six-minute walk distance is due to compromised oxygen delivery, decreased cardiac reserve, and increased right ventricular afterload.

Applying machine learning methods to develop a successful aging maintenance prediction model based on physical fitness tests

AIM

The purpose of this study was to develop a machine learning prediction model for successful aging (SA) based on physical fitness tests.

METHODS

A total of 3657 community-dwelling adults aged ≥60 years from Nanchang city were recruited in this study. A 3-year follow-up test was carried out for all the participants to determine whether they turn to non-SA. Developed questionnaires and physical fitness tests were used to obtain overall health condition, balance, agility, speed, reactions and gait. Four machine learning models (logistic regression, deep learning, random forest and gradient boosting decision tree) were applied to develop the prediction models, the analyzed sample was 890.

RESULTS

The baseline prevalence of successful aging was 26.99%, The average annual incidence rate of SA to non-SA was 11.04%. There were significant differences between the SA and non-SA groups for all physical fitness tests at baseline. The accuracy and area under the curve of all four machine learning models was >85%, the positive predictive value and sensitivity was >75%, and the specificity was >86% on the average. The deep learning model outperformed the other model, with area under the curve 90.00%, accuracy 89.3%, positive predictive value 85.8% and specificity 93.1%, respectively. Compared with other models, the logistic regression model performed best in sensitivity. Age, arm curl, 30-s sit-to-stand and reaction time were important predictors in all models.

CONCLUSION

The deep learning model is ideal in the prediction of SA maintenance, and the corresponding physical fitness interventions are essential to ensuring SA. Geriatr Gerontol Int 2020; ••: ••-••.

Relationships between respiratory muscle strength, chest wall expansion, and functional capacity in healthy nonsmokers

Chest wall expansion determines lung volume and functional capacity. Factors determining chest wall expansion include respiratory muscle strength. Accordingly, there may be association among respiratory muscle strength, chest wall expansion, and functional capacity. Thusly, this cross-sectional study identified the relationship between respirato-ry muscle strength, chest wall expansion, and functional capacity. Seventy-six healthy male and female participants aged between 20 to 59 years exhibiting a body mass index of 18.5 to 22.9 kg/m² were enrolled. Inspiratory and expiratory muscle strength were evaluated via maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), respectively. Chest wall expansion was measured through thoracic circumferences at three different levels; upper, middle, and lower levels with diaphragmatic movement also measured utilizing the circumference of the lower edge of the 10th rib. Functional capacity was evaluated through distance obtained from a 6-min walk test. Results showed that both MIP and MEP were significantly correlated with chest wall expansion at the middle (P=0.005 and P=0.006) and lower (P=0.012 and P=0.020) thoracic levels as well as diaphragmatic movement (both P<0.001). Moreover, both MIP and MEP were significantly related amid the 6-min walk distance (P=0.025 and P<0.001). In conclusion, respiratory muscle strength is positively associated with chest wall expansion, diaphragmatic movement, and functional capacity in healthy participants.

A MULTI-MARKER MODEL FOR PREDICTING DECOMPENSATED HEART FAILURE IN PATIENTS WITH PRIOR ACUTE MYOCARDIAL INFARCTION

The aim of the study was to assess the prognostic value of determining the plasma concentration of NT-proBNP and ST2 in the patients with decompensated HF and prior acute myocardial infarction and their combination in this category of patients. Materials and methods. There were examined 120 patients with acute myocardial infarction and stage II A-B decompensated chronic HF according to the classification proposed by Vasylenko V. Kh. and Strazhesko M.D., NYHA functional class (FC) III-IV. The patients with Q-QS wave MI (60 individuals) and non Q MI (60 individuals) were divided into 4 groups depending on the treatment methods. Study groups were homogenous by age, gender, disease severity, duration of the post-infarction period, clinical signs of decompensation, which served as a basis for inclusion of the patients in the study. All the patients underwent the six-minute walk test in a quiet 30-50-m long hospital corridor in the morning. N-terminal pro-B-type brain natriuretic peptide (NT-proBNP) and ST-2 were analyzed in all patients. Results. Promising biomarkers of HF decompensation in the post-infarction period were studied. In the patients with prior Q-QS MI and decompensated HF, NT-proBNP level was (950.38±3.15) pmol/l (p<0.05); in the patients with prior MI without signs of decompensated HF, it was (580.15±3.03) pmol/l (p˂0.05); in apparently healthy individuals, the level of NT-proBNP was found to be (111.20±3.47) pmol/l. ST2 level was (14.80±1.61) ng/ml, (36.00±1.43) ng/ml and (49.22±1.40) ng/ml in the patients of Group 1, Group 2 and Group 3, respectively (p˂0.05). Similar changes were found in patients with decompensated HF in postinfarction period after non Q MI. Conclusions. The increase in plasma concentration of sST2 is associated with the activation of both neurohumoral and fibrous pathways and can help in detecting the patients with decompensated HF in the post-infarction period and predicting the risk of its development. Our results confirmed the results of other multiple studies reporting ST2 in combination with NT-proBNP to be valuable tools for prognosing the development of decompensated HF in the patients with prior MI. ST2, alongside with NT-proBNP, is a promising biomarker to be included in the diagnostic panel for detecting acute HF and can provide additional information on risk stratification for such patients during hospitalization and at the time of discharge from the hospital.

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.

Effects of sacubitril/valsartan on functional status and exercise capacity in real-world patients

Background: Sacubitril/valsartan significantly reduced heart failure(HF) hospitalisations and mortality in the PARADIGM-HF-trial. However real-world data on symptomatic and functional improvement are lacking. Methods: Between December 2016 and January 2018, we retrospectively collected baseline and follow-up data including New York Heart Association (NYHA)-functional class and Cardio-pulmonary exercise data(CPET) in all HF-patients receiving sacubitril/valsartan. Additionally, in patients with an implantable electric cardiovascular device (IECD) enrolled in remote telemonitoring, we quantified patient level activity before and after initiation. Results: A total of 201 patients (82% males) were identified. NYHA-functional class was reassessed after an average of 221 ± 114 days. Overall, 3.3% of patients improved 2 NYHA classes, 28.7% improved 1 NYHA class, 64% remained stable and 4% deteriorated 1 NYHA class. Patients with symptomatic improvement exhibited a larger reduction in Left Ventricular End Systolic Volume(LVESV) and a larger increase in Left Ventricular Ejection Fraction(LVEF[p-value both <.05]). In total, 110 patients (55%) were equipped with an IECD capable of quantifying outpatient activity-level. On an average of 364 days before sacubitril/valsartan, an activity expressed as %-of-the-day was 13 ± 2%, vs. 18 ± 3% the 364 days following sacubitril/valsartan initiation. Signifying a 38% improvement in the out-patient activity level. CPET-data was obtained in paired-fashion in 45 patients (22%). VO_2max at baseline (14.7 ± 3.8 mL/kg/min) did not significantly change at follow-up (14.1 ± 4.7 mL/min/kg; p = .237). Conclusion: Real-world patients exhibit significant symptomatic and functional improvement following the initiation of sacubitril/valsartan. However, larger prospective studies are necessary to assess the impact of sacubitril/valsartan on indices of maximal exercise performance measured during CPET.

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.

Endocan Is an Independent Predictor of Heart Failure-Related Mortality and Hospitalizations in Patients with Chronic Stable Heart Failure

Background

Heart failure (HF) is characterized by unfavorable prognosis. Disease trajectory of HF, however, may vary, and risk assessment of patients remains elusive. In our study, we sought to determine the prognostic impact of endocan—a novel biomarker of endothelial dysfunction and low-grade inflammation—in patients with heart failure.

Methods

In outpatients with chronic HF, baseline values of endocan were determined and clinical follow-up for a minimum of 18 months obtained. A multivariate Cox proportional hazard model was built for HF-related death or hospitalization requiring inotropic support.

Results

A total of 120 patients (mean age 71 years, 64% male, mean LVEF 36%) were included. During a mean follow-up of 656 ± 109 days, 50 patients (41.6%) experienced an event. On Cox multivariate analysis, endocan values emerged as an independent predictor of HF prognosis (HR, 1.471 CI 95% 1.183-1.829, p = 0.001, for each 1 ng/mL increase) even after adjustment for age, gender, HF etiology, LVEF, NYHA class, NT-proBNP, and exercise tolerance.

Conclusions

Endocan is an independent predictor of HF-related events in chronic HF individuals and represents a promising tool for risk assessment of HF patients.

The Use of Intranasal Fentanyl for the Palliation of Incident Dyspnea in Advanced Congestive Heart Failure: A Pilot Study

Background:

Dyspnea is distressing in palliative patients with end-stage heart failure and many are hospitalized to optimize this symptom. We hoped to conduct a pilot study to determine whether the administration of intranasal fentanyl would decrease activity-induced dyspnea in this patient population.

Methods:

Patients performed two 6-minute walk tests with and without the administration of 50 μg of intranasal fentanyl. Vital signs were recorded before and after each walk, as were participant reported dyspnea and adverse events scores.

Results:

Twenty-four patients were screened, 13 were deemed eligible, and 6 completed the study. Dyspnea scores changed from a mean of 6.00 immediately after the walk without fentanyl to a mean of 3.83 after the walk with fentanyl ( P = .048). Mean respiratory rate decreased from 21.0 to 18.7 ( P = .034) breaths per minute and was considered a favorable outcome by the participants. Distance walked did not significantly increase with the fentanyl pretreatment (136.0-144.2 m; P = .283), although the participants reported feeling better while walking a similar distance.

Conclusions:

In this pilot study, the preadministration of intranasal fentanyl prior to activity in palliative, end-stage hospitalized heart failure patients, safely reduced tachypnea, and the feeling of shortness of breath. This approach may help palliate advanced heart failure patients by alleviating symptoms brought on by exertional activities.

Sacubitril/Valsartan: Effect on Walking Test and Physical Capability

The 6-min walk test (6MWT) is a simple and inexpensive exercise test to evaluate physical functional capacity that is widely used in heart failure (HF) patients. With the 6MWT, a distance <350 m is associated with increased mortality in patients with HF, and change in walking distance >50 m is considered clinically relevant. To our knowledge, information on improvement in physical functional capacity with sacubitril/valsartan, as assessed by the 6MWT, is still scant. In our daily practice, we apply this test to all patients whenever possible; therefore, we report here the findings observed in a small series of 5 patients with HF with reduced ejection fraction after a 1-month treatment with sacubitril/valsartan at full dose. The mean distance walked on the 6MWT at baseline was 129 m (±64 SD), and this value increased to 436 m (±156) after 1 month of therapy with sacubitril/valsartan 97/103 mg b.i.d. The mean difference from baseline was 305 m (±110). According to these preliminary findings, in clinical practice, a 1-month therapy of sacubitril/valsartan optimized at a 97/103-mg b.i.d. dose appears to be associated with a relevant improvement in the 6MWT.

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.