Submaximal Exercise Capacity Research Articles

Limiting factors of peak and submaximal exercise capacity in LVAD patients.

AimsAlthough patients supported with a Continuous-Flow Left Ventricular Assist Device (CF-LVAD) are hemodynamically stable, their exercise capacity is limited. Hence, the aim of this work was to investigate the underlying factors that lead to peak and submaximal exercise intolerance of CF-LVAD supported patients.MethodsSeven months after CF-LVAD implantation, eighty three patients performed a maximal cardiopulmonary exercise test and a six minute walk test. Peak oxygen uptake and the distance walked were measured and expressed as a percentage of the predicted value (%VO2p and %6MWD, respectively). Preoperative conditions, echocardiography, laboratory results and pharmacological therapy data were collected and a correlation analysis against %VO2p and %6MWD was performed.ResultsCF-LVAD patients showed a relatively higher submaximal exercise capacity (%6MWD = 64±16%) compared to their peak exertion (%VO2p = 51±14%). The variables that correlated with %VO2p were CF-LVAD parameters, chronotropic response, opening of the aortic valve at rest, tricuspid insufficiency, NT-proBNP and the presence of a cardiac implantable electronic device. On the other hand, the variables that correlated with %6MWD were diabetes, creatinine, urea, ventilation efficiency and CF-LVAD pulsatility index. Additionally, both %6MWD and %VO2p were influenced by the CF-LVAD implantation timing, calculated from the occurrence of the cardiac disease.ConclusionOverall, both %6MWD and %VO2p depend on the duration of heart failure prior to CF-LVAD implantation. %6MWD is primarily determined by parameters underlying the patient’s general condition, while %VO2p mostly relies on the residual function and chronotropic response of the heart. Moreover, since %VO2p was relatively lower compared to %6MWD, we might infer that CF-LVAD can support submaximal exercise but is not sufficient during peak exertion. Hence concluding that the contribution of the ventricle is crucial in sustaining hemodynamics at peak exercise.

Iron Deficiency: Impact on Functional Capacity and Quality of Life in Heart Failure with Preserved Ejection Fraction.

The effects of iron deficiency (ID) have been widely studied in heart failure (HF) with reduced ejection fraction. On the other hand, studies in HF with preserved ejection fraction (HFpEF) are few and have included small numbers of participants. The aim of this study was to assess the role that ID plays in functional capacity and quality of life (QoL) in HFpEF while comparing several iron-related biomarkers to be used as potential predictors. ID was defined as ferritin <100 ng/mL or transferrin saturation <20%. Submaximal exercise capacity, measured by the 6-min walking test (6MWT), and QoL, assessed by the Minnesotta Living with Heart Failure Questionnaire (MLHFQ), were compared between iron deficient patients and patients with normal iron status. A total of 447 HFpEF patients were included in the present cross-sectional study, and ID prevalence was 73%. Patients with ID performed worse in the 6MWT compared to patients with normal iron status (ID 271 ± 94 m vs. non-ID 310 ± 108 m, p < 0.01). They also scored higher in the MLHFQ, denoting worse QoL (ID 49 ± 22 vs. non-ID 43 ± 23, p = 0.01). Regarding iron metabolism biomarkers, serum soluble transferrin receptor (sTfR) was the strongest independent predictor of functional capacity (β = −63, p < 0.0001, R2 0.39) and QoL (β = 7.95, p < 0.0001, R2 0.14) in multivariate models. This study postulates that ID is associated with worse functional capacity and QoL in HFpEF as well, and that sTfR is the best iron-related biomarker to predict both. Our study also suggests that the effects of ID could differ among HFpEF patients by left ventricular ejection fraction.

Exercise Capacity and Activities of Daily Living are Related in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe knowledge of the relationship between exercise capacity and activities of daily living (ADLs) is important to minimize the negative outcomes in ADLs resulting from reduced exercise capacity in patients with chronic obstructive pulmonary disease (COPD). There is a limited study about the association between exercise capacity and ADLs in patients with COPD. This study aimed to investigate the relationship between maximal exercise capacity and ADLs in patients with GOLD stage II–III COPD. MethodsTwenty-seven clinically stable GOLD stage II–III COPD patients were included (mean age=58.59±9.63 years and mean FEV1=50.6±13.7%) in this cross-sectional study. Maximal and submaximal exercise capacity were evaluated using an incremental shuttle walk test (ISWT) and 6-min walk test (6MWT), respectively. Activities of daily living were assessed using Glittre-ADL test. ResultsThe ISWT distance was significantly correlated with Glittre-ADL test time (r=−0.517, p=0.006). There was also a negative correlation between 6MWT distance and Glittre-ADL test time (r=−0.506, p=0.007). ConclusionA moderate relationship was found between maximal exercise capacity and general activities of daily living performance. The reduction in exercise capacity increases the negative influences in ADLs and strengthens our beliefs that exercise interventions in pulmonary rehabilitation could influence activities of daily living positively.

Right Ventricular Function Coupling to the Pulmonary Circulation Predicts Exercise Tolerance in Patients with Heart Failure and Reduced Ejection Fraction. Insight from the Evaluation of Resynchronization Therapy for Heart Failure (EARTH) Trial

Exercise tolerance has important prognostic value in patients with heart failure and reduced ejection fraction (HFrEF). The relationship between right ventricular function and its coupling to pulmonary circulation (RV-PA) and cardiopulmonary exercise tests (CPET) is not fully understood. We aimed to evaluate the value of RV echocardiographic parameters, including RV-PA, to predict exercise tolerance in HFrEF patients. We performed a sub-analysis of EARTH, which enrolled HFrEF patients undergoing defibrillator implantation. At baseline, an echocardiogram and various CPET [peak VO2; minute ventilation/carbon dioxide production slope (VE/VCO2); 6-minute walk distance (6MWD) and submaximal exercise duration (SED)] were performed. The primary outcome was the correlation of RV-PA (using TAPSE/sPAP, tricuspid annular plane systolic excursion on pulmonary artery systolic pressure ratio (T/P)) with peak VO2. Secondary outcomes include correlation between various RV parameters such as size [diameter at inlet and end-diastolic area in apical 4-chamber], RV function [TAPSE; right ventricular fractional area change (RV-FAC); RV myocardial performance index (RV-MPI)], sPAP and tricuspid regurgitation grade (TRG); and CPET variables. Univariate and multivariate linear regression models were used on patients for which both TAPSE and sPAP were available. 205 patients were enrolled in EARTH, with 100 having data on both TAPSE and sPAP (Men: 70.0%; NYHA class II: 55.0%; mean LVEF 26.5±7.8%). T/P was the only parameter found to be predictive of peak VO2 (β=6.8, p<0.01), together with BMI for 6MWD (β=72.4, p=0.04). ROC analysis for T/P value predictive of peak VO2 ≤14mL/kg/min showed sensitivity and specificity of 0.63 and 0.62 respectively, and area under the curve (AUC) of 0.66 (p<0.01) for an optimal threshold ≤0.45. T/P and RV-MPI were both predictors (β=-18.0, p<0.01; β=18.5, p<0.01 respectively) of VE/VCO2 slope, while only TRG and BMI predicted SED (β=-3.2, p=0.03). In HFrEF patients, RV-PA coupling (using TAPSE/sPAP) is a powerful predictor of maximal and submaximal exercise capacity and has a greater predictive value than the usual parameters including age, sex and LVEF.

Effects of exergaming on exercise capacity inpatients with heart failure: results of an international multicentre randomized controlled trial.

AbstractAimsExergaming is a new tool to increase physical activity. This study aimed to determine the effects of access to a home‐based exergame (Nintendo Wii) in patients with heart failure (HF) on exercise capacity, self‐reported physical activity and patient‐reported outcome measures.Methods and resultsWe enrolled 605 HF patients in New York Heart Association functional class I–IV, independent of ejection fraction, in an international multicentre randomized controlled trial. Patients were randomized to exergame (intervention) or motivational support (control). The primary endpoint was change in submaximal aerobic exercise capacity as measured by the distance walked in 6 min (6MWT) between baseline and 3 months. Secondary endpoints included long‐term submaximal aerobic exercise capacity, muscle function, self‐reported physical activity, exercise motivation, exercise self‐efficacy at 3, 6 and 12 months. At baseline, patients on average walked 403 ± 142 m on the 6MWT. Patients in the exergame group walked further compared to controls at 3 months (454 ± 123 vs. 420 ± 127 m, P = 0.005), at 6 months (452 ± 123 vs. 426 ± 133 m, P = 0.015) and 12 months (456 ± 122 vs. 420 ± 135 m, P = 0.004). However, correcting for baseline 6MWT values by means of a linear mixed‐effects model revealed no main effect for the intervention on 6MWT. Small significant effects on muscle function were found. Statistically significant treatment effects were found for muscle function but after correction for baseline and confounders, only the treatment effect for the heel‐rise left at 6 months was significant (P &lt; 0.05). No treatment effect was found for exercise motivation, exercise self‐efficacy, or self‐reported physical activity.ConclusionExergaming was safe and feasible in patients with HF with different profiles in different health care systems, cultures and climates. However, it was not effective in improving outcomes on submaximal aerobic exercise capacity. Subgroup analysis did not identify specific subgroups benefiting from the intervention.Clinical Trial Registration: ClinicalTrial.gov Identifier: NCT01785121.

Quality of life in heart failure with preserved ejection fraction: importance of obesity, functional capacity, and physical inactivity.

Patient-reported quality of life (QOL) is a highly prognostic and clinically relevant endpoint in patients with heart failure (HF) with preserved ejection fraction (HFpEF). The relationships between QOL and different markers of HF severity remain unclear, particularly as they relate to functional capacity and directly measured activity levels. We hypothesized that QOL would demonstrate a stronger relationship with measures of exercise capacity and adiposity compared to other disease measures. This is a secondary analysis of the National Heart, Lung, and Blood Institute-sponsored RELAX, NEAT-HFpEF and INDIE-HFpEF trials to determine the relationships between QOL (assessed by the Kansas City Cardiomyopathy Questionnaire and Minnesota Living with Heart Failure Questionnaire) and different domains reflecting HF severity, including maximal aerobic capacity (peak oxygen consumption), submaximal exercise capacity (6-min walk distance), volume of daily activity (accelerometry), physician-estimated functional class, resting echocardiography, and plasma natriuretic peptide levels. A total of 408 unique patients with chronic HFpEF were split into tertiles of QOL scores defined as QOLworst, QOLintermediate , QOLbest . The QOLworst HFpEF group was youngest, with a higher body mass index, greater prevalence of class II obesity and diabetes, and the lowest N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. After adjustment for age, sex and body mass index, poorer QOL was associated with worse physical capacity and activity levels, assessed by peak oxygen consumption, 6-min walk distance and actigraphy, but was not associated with NT-proBNP or indices from resting echocardiography. QOL was similarly reduced in patients with and without prior HF hospitalization. Quality of life in HFpEF is poorest in patients who are young, obese and have diabetes, and is more robustly tied to measures reflecting functional capacity and daily activity levels rather than elevations in NT-proBNP or prior HF hospitalization. These findings have major implications for the understanding of QOL in HFpEF and for the design of future clinical trials targeting symptom improvement in HFpEF. RELAX, NCT00763867; NEAT-HFpEF, NCT02053493; INDIE-HFpEF, NCT02742129.

RIGHT VENTRICULAR FUNCTION COUPLING TO THE PULMONARY CIRCULATION PREDICTS EXERCISE TOLERANCE IN PATIENTS WITH HEART FAILURE AND REDUCED EJECTION FRACTION: INSIGHT FROM THE EVALUATION OF RESYNCHRONIZATION THERAPY FOR HEART FAILURE (EARTH) TRIAL

Purpose Exercise tolerance has important prognostic value in patients with heart failure and reduced ejection fraction (HFrEF). The relationship between right ventricular function and its coupling to pulmonary circulation (RV-PA) and cardiopulmonary exercise tests (CPET) is not fully understood. We aimed to evaluate the value of RV echocardiographic parameters, including RV-PA, to predict exercise tolerance in HFrEF patients. Methods We performed a sub-analysis of EARTH, which enrolled HFrEF patients undergoing defibrillator implantation. At baseline, an echocardiogram and various CPET [peak VO2; minute ventilation/carbon dioxide production slope (VE/VCO2); 6-minute walk distance (6MWD) and submaximal exercise duration (SED)] were performed. The primary outcome was the correlation of RV-PA (using TAPSE/sPAP, tricuspid annular plane systolic excursion on pulmonary artery systolic pressure ratio (T/P)) with peak VO2. Secondary outcomes include correlation between various RV parameters such as size [diameter at inlet and end-diastolic area in apical 4-chamber], RV function [TAPSE; right ventricular fractional area change (RV-FAC); RV myocardial performance index (RV-MPI)], sPAP and tricuspid regurgitation grade (TRG); and CPET variables. Univariate and multivariate linear regression models were used on patients for which both TAPSE and sPAP were available. Results 205 patients were enrolled in EARTH, with 100 having data on both TAPSE and sPAP (Men: 70.0%; NYHA class II: 55.0%; mean LVEF 26.5±7.8%). T/P was the only parameter found to be predictive of peak VO2 (β=6.8, p Conclusion In HFrEF patients, RV-PA coupling (using TAPSE/sPAP) is a powerful predictor of maximal and submaximal exercise capacity and has a greater predictive value than the usual parameters including age, sex and LVEF.

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise.

Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin. We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance. The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia. Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts. High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange. The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n=11, n=8 females) with HAH (P50 =16±1mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 =26±1, n=14, n=8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end-exercise arterial oxygen tension in hypoxia (59±6 vs. 59±9mmHg for controls and HAH, respectively), the HAH subjects' oxyhaemoglobin saturation ( ) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake ( ) (4±5% vs. 12±%, p<0.001) in hypoxia and the change in between trials was related to the change in (r=-0.75, p<0.0001). Compared to normoxia, the controls' alveolar-to-arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.

The effect of global longitudinal strain on ımpaired six-minute walk test performance in patients with sarcoidosis.

Background:Sarcoidosis is a multisystem and granulomatous disease associated with impaired functional capacity as a result of pulmonary and cardiac involvement. Factors adversely effecting functional capacity in patients with sarcoidosis have not been systematically assessed including myocardial strain imaging on echocardiography which enable to diagnose subclinical cardiac dysfunction. We aimed to evaluate the effect of left and right ventricular global longitudinal strain (GLS) on submaximal exercise capacity in patients with sarcoidosis who do not have clinically manifest cardiac involvement.Methods:Extracardiac biopsy proven 56 patients with sarcoidosis and 26 controls were included consecutively. Submaximal exercise capacity of the subjects was assessed with six-minute walk test (6 MWT). Pulmonary function tests and standard transthoracic and two-dimensional speckle tracking echocardiography were performed to the all subjects. Linear regression analysis was performed to find independent predictors of 6 MWT.Results:Fifty-six patients (18% male) with a mean age of 52.5 ± 10.7 years were included. Patients with sarcoidosis had low 6 MWT performance and higher New York Heart Association classes and NT-proBNP levels. There were no significant differences between controls and patients with sarcoidosis in parameters of pulmonary function test. Biventricular GLS levels and biatrial reservoir and conduit function values were lower and systolic pulmonary artery pressure (SPAP) was significantly higher in patients with sarcoidosis as compared with controls. Older age and higher SPAP were found as independent predictors of poor 6 MWT performance.Conclusion:Although biventricular GLS levels were lower in the patients with sarcoidosis, only age and SPAP elevations were independent predictors of the submaximal exercise capacity. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (1): 63-73)

EXPRESS: Riociguat for the treatment of transthyretin cardiac amyloidosis - Data from a named patient use program in Austria.

Patients with transthyretin cardiac amyloidosis (TTR CA) suffer from impaired exercise capacity, have a poor quality of life (QoL), and approved treatments are lacking. Stimulators of the soluble guanylate cyclase are promising new pharmaceuticals in the treatment armamentarium of heart failure patients. The aim of the present study was to report on the safety and efficacy of riociguat administration in patients with TTR CA. TTR CA patients received riociguat for 4–6 months within the frames of a national named patient use (NPU) program. Parameters of interest included changes in submaximal exercise capacity, invasive hemodynamic parameters, and QoL. Between March 2012 and June 2017, 86 CA patients were screened for the NPU program, of whom 13 TTR CA patients were eligible for participation. In our study cohort, riociguat had an acceptable tolerability profile. At follow‐up, we could detect slight improvements in median 6‐min walk distance (396 m [interquartile range (IQR) = 340–518] vs. 400 m [IQR = 350–570], P = 0.045), New York Heart Association class ≥ III (n = 7 [53.9%] vs. n = 0 [0.0%], P = 0.031), cardiac output (4.3 L/min [IQR = 3.9–5.1] vs. 4.5 L/min [IQR = 4.2–5.1], P = 0.022), diastolic pressure gradient (1.0 mmHg [IQR = −1.5–3.0) vs. −1.0 mmHg [IQR = −3.0–1.0], P = 0.049), and QoL (50.0% [IQR = 40.0–58.0] vs. 60.0% [IQR = 50.0–75.0], P = 0.021). Pulmonary arterial pressures were not altered. The present case series of TTR CA patients indicates that riociguat administration was safe and associated with minor clinical as well as hemodynamic improvements.

Improving physical performance through independent, home-based exercise program prior to cancer-related surgery.

54 Background: Surgery in older adults is a physiologically stressful event associated with reduced functional capacity and decreased quality of life. Poor preoperative performance is linked to risk of postoperative complications and prolonged functional recovery. The goal of this study is to determine the efficacy of an independent, home-based exercise program in improving physical performance prior to cancer-related surgery. Methods: Retrospective study of 217 consecutive patients referred for comprehensive prehabilitation including physical medicine and rehabilitation physician and physical therapy visits prior to intended oncologic surgery. Physical performance was assessed at consultation (baseline) and at the preoperative follow up visit in physical therapy. Physical performance measures included Six-Minute Walk test (6MWT), Five Times Sit to Stand (5xSTS), hand grip strength (HGS), gait speed (GS), and Timed Up and Go (TUG). Results: Median (IQR) age was 71 (64,77). The most common primary cancer diagnoses were gastrointestinal (43%), genitourinary (15%), breast (9%), and sarcoma (7%). 144 of the 217 (66%) underwent surgery and of these, 75 (52%) completed preoperative functional measures during their physical therapy follow-up. For the entire cohort of 217 patients, baseline median (IQR) measures included: 6MWT distance was 357 (193.3, 420) meters, 5xSTS was 12 (9.1, 16.3) seconds, right HGS was 43.3 (30.0, 58.3) pounds, GS was 1.4 (1, 1.7) meters per second, and TUG was 8.6 (7.3, 12.2) seconds. There were similar baseline physical function results in the cohort who completed preoperative measures. During the preoperative period (from baseline to pre-surgery visit), there was significant improvement in the 6MWT ( P=0.003), 5xSTS ( P=0.000), and TUG ( P=0.027). There was no significant change in HGS or GS. Conclusions: At baseline, most patients had major functional impairment, especially decreased submaximal exercise capacity. With the independent, home-based exercise prehabilitation program, patients had significant improvement in physical performance. Prehabilitation should be further investigated in these patients.

Impaired heart rate variability, Valsalva and 30:15 ratio indexes are associated with reduced submaximal exercise capacity in subjects with diabetes mellitus

AimsTo assess cardiac autonomic control and its association with submaximal exercise measured using the 6-minute walk test (6MWT) in subjects with type-2 diabetes mellitus (DM2). MethodsCardiac autonomic control was assessed using Ewing’s tests and heart rate variability (HRV) in DM2 volunteers (DG, n = 22) and sex-, age- and body mass index-matched non-diabetic controls (CG, n = 22) before, during and after 6MWT. ResultsBefore the 6MWT, DG presented lower HRV represented by reduced SDNN [median 28.9 ms2 (IQR:18.6–35.4) vs. 45.1 (IQR:39.2–62.67), p < 0.001] and Total Power [median 785 ms2 (IQR:256–1264) vs. 1757 ms2 (IQR:1006–2912), p = 0.004]. Exercise capacity was reduced in DG [maximal predicted distance (%) = 88.4 ± 6.4 vs. 95.2 ± 11.0%, p = 0.018]. DG demonstrated lower global HRV during recovery and lower parasympathetic drive, represented by reduced RMSSD, during all phases of the 6MWT. Moreover, supine HR (r = −0.32), HR orthostatism (ρ = −0.40), SDNN pre-6MWT (ρ = 0.39), TP pre-6MWT (ρ = 0.38), Valsalva ratio (ρ = 0.39) and 30:15 ratio (ρ = 0.38) were all correlated with maximal walked distance. ConclusionsDM2 subjects presented abnormal HRV during and after submaximal exercise. Furthermore, autonomic control impairment in orthostatism, represented by lower global HRV (SDNN, Total power) and lower Ewing’s indexes (Valsalva and 30:15 ratios), was associated with lower exercise capacity.

Quality of Life in Heart Failure with Preserved Ejection Fraction: Differential Associations with Exercise Performance, Daily Activity Levels and Ventricular Function

Introduction Patient-reported quality of life (QOL) is a highly prognostic and clinicially relevant endpoint in patients with Heart Failure with preserved Ejection Fraction (HFpEF). The relationships between QOL and different markers of HF severity remain unclear. Hypothesis QOL will demonstrate a stronger relationship with measures of exercise capacity compared to other disease measures. Methods This is a secondary analysis of the NHLBI-sponsored RELAX, NEAT and INDIE trials to determine the relationships between QOL (assessed by the Kansas City Cardiomyopathy Questionaire and Minnesota Living with Heart Failure Questionaire) and different domains reflecting HF severity, including maximal aerobic capacity (peak oxygen consumption, VO2), submaximal exercise capacity (6 minute walk distance), volume of daily activity (accelerometry), physician-estimated functional class, resting echocardiography and plasma natriuretic peptide levels. Results A total of 408 unique patients with chronic HFpEF were split into tertiles of QOL scores defined as QOLworst, QOLintermediate, QOLbest. The QOLworst HFpEF group was youngest, with a higher BMI and greater prevalence of diabetes but the lowest NT-proBNP levels (Table). After adjustment for age, sex and BMI; poorer QOL was associated with worse peak VO2, 6 minute walk distance and accelerometry based measures, but no relationship was seen with NT-proBNP or indices from resting echocardiography. Conclusions QOL in HFpEF is most impaired in patients who are young, obese and have diabetes, and in those with lowest NTproBNP levels, and is more robustly tied to measures of exercise capacity and reduced daily activity levels rather than elevations in NT-proBNP. These findings have major implications for the understanding of QOL in HFpEF and for the design of future clinical trials targeting symptom improvement in HFpEF.

Exercise Capacity and Activities of Daily Living are Related in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe knowledge of the relationship between exercise capacity and activities of daily living (ADLs) is important to minimize the negative outcomes in ADLs resulting from reduced exercise capacity in patients with chronic obstructive pulmonary disease (COPD). There is a limited study about the association between exercise capacity and ADLs in patients with COPD. This study aimed to investigate the relationship between maximal exercise capacity and ADLs in patients with GOLD stage II–III COPD. MethodsTwenty-seven clinically stable GOLD stage II–III COPD patients were included (mean age=58.59±9.63 years and mean FEV1=50.6±13.7%) in this cross-sectional study. Maximal and submaximal exercise capacity were evaluated using an incremental shuttle walk test (ISWT) and 6-min walk test (6MWT), respectively. Activities of daily living were assessed using Glittre-ADL test. ResultsThe ISWT distance was significantly correlated with Glittre-ADL test time (r=−0.517, p=0.006). There was also a negative correlation between 6MWT distance and Glittre-ADL test time (r=−0.506, p=0.007). ConclusionA moderate relationship was found between maximal exercise capacity and general activities of daily living performance. The reduction in exercise capacity increases the negative influences in ADLs and strengthens our beliefs that exercise interventions in pulmonary rehabilitation could influence activities of daily living positively.

Characterization of the Obese Phenotype of Heart Failure With Preserved Ejection Fraction: A RELAX Trial Ancillary Study

ObjectiveTo characterize the obese heart failure with preserved ejection fraction (HFpEF) phenotype in a multicenter cohort. Patients and MethodsThis was a secondary analysis of the randomized clinical trial RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure with Preserved Ejection Fraction) performed between October 1, 2008, and February 1, 2012. Patients with HFpEF were classified by body mass index (BMI) as obese (BMI≥35 kg/m2) and nonobese (BMI<30 kg/m2) for comparison. ResultsObese patients with HFpEF (n=81) were younger (median age, 64 [interquartile range (IQR), 67-79] years vs 73 [IQR, 56-70] years; P<.001) but had greater peripheral edema (31% [25] vs 9% [6]; P<.001), more orthopnea (76% [56] vs 53% [35]; P=.005), worse New York Heart Association class (P=.006), and more impaired quality of life (P<.001) as compared with nonobese patients with HFpEF (n=70). Despite more severe signs and symptoms, obese patients with HFpEF had lower N-terminal pro B-type natriuretic peptide level (median, 481 [IQR, 176-1183] pg/mL vs 825 [IQR, 380-1679] pg/mL [to convert to pmol/L, multiply by 0.118]; P=.007) and lower left atrial volume index (median, 38 [IQR, 31-47] mL/m2 vs 54 [IQR, 41-63] mL/m2; P<.001). Serum C-reactive protein (median, 5.0 [IQR, 2.4-9.9] mg/dL vs 2.7 [IQR, 1.6-5.4] mg/dL [to convert to mg/L, multiply by 10−3]; P<.001) and uric acid (median, 7.8 [IQR, 6.1-8.7] mg/dL vs 6.8 [IQR, 5.5-8.3] mg/dL; P=.03) levels were higher in obese HFpEF, indicating greater systemic inflammation, than in nonobese HFpEF. Peak oxygen consumption was impaired in obese HFpEF (median, 11.1 [IQR, 9.6-14.4] mL/kg per minute vs 13.1 [IQR, 11.3-14.7] mL/kg per minute; P=.008), as was submaximal exercise capacity (6-minute walk distance, 272 [IQR, 200-332] m vs 355 [IQR, 290-415] m; P<.0001). ConclusionObese HFpEF is associated with decreased quality of life, worse symptoms of heart failure, greater systemic inflammation, worse exercise capacity, and higher metabolic cost of exertion as compared with nonobese HFpEF. Further study is required to understand the pathophysiology and potential distinct treatments for patients with the obese phenotype of HFpEF. Trial Registrationclinicaltrials.gov Identifier: NCT00763867

The combination of exercise training and sodium-glucose cotransporter-2 inhibition improves glucose tolerance and exercise capacity in a rodent model of type 2 diabetes

PurposeExercise is recommended in addition to pharmacotherapies for the management of type 2 diabetes, but metformin and exercise training may have non-additive or even inhibitory effects on exercise-induced improvements in glycemic control and exercise capacity. The objectives of this report were to determine if co-treatment with a sodium-glucose cotransporter-2 inhibitor and exercise could (1) further improve glycemic control when compared to either monotherapy and (2) not worsen exercise capacity when compared to exercise alone. MethodsA rodent model of type 2 diabetes (30 mg/kg streptozotocin and high-fat feeding in male Sprague-Dawley rats) was used to assess 12 weeks of co-treatment with a sodium-glucose cotransporter 2 inhibitor (SGLT2i) and exercise (EX; treadmill running) on glycemic control and exercise capacity. Animals were randomized to the following conditions (n = 7–10/group): vehicle (0.5% methyl cellulose) sedentary (VEH SED), VEH EX, canagliflozin (3 mg kg−1 d−1) SED (SGLT2i SED), or SGLT2i EX. ResultsBoth EX and SGLT2i independently improved indices of glycemic control. The combination of SGLT2i and EX further improved glucose tolerance (glucose area under the curve 1109 ± 51 vs 1427 ± 82 mmol/ L 120 min−1 for SGLT2i EX vs. SGLT2i SED, respectively; p < 0.05) and insulin responses (insulin area under the curve 24,524 ± 4126 vs. 41,208 ± 2714 pmol L−1 120 min−1 for SGLT2i EX vs. VEH EX, respectively; p < 0.05) during an oral glucose tolerance test. Only the combination of SGLT2i EX lowered body weight compared to VEH SED (p < 0.01). SGLT2i caused several metabolic adaptations including increased ketone production and a greater reliance on fat as a source of energy during normal cage activity. Interestingly, animals that were given the SGLT2i and underwent exercise training (SGLT2i EX) had better submaximal exercise capacity than EX alone, as indicated by distance run prior to fatigue (882 ± 183 vs.433 ± 33 m for SGLT2i EX and VEH EX, respectively; p < 0.01), and this was accompanied by a greater reliance on fat as an energy source during exercise (p < 0.01). ConclusionsIf these findings with the combination of SGLT2i and exercise translate to humans, they will have important clinical health implications.

Effect of a Ketogenic Diet on Submaximal Exercise Capacity and Efficiency in Runners.

We investigated the effect of a 31-d ketogenic diet (KD) on submaximal exercise capacity and efficiency. A randomized, repeated-measures, crossover study was conducted in eight trained male endurance athletes (V˙O2max, 59.4 ± 5.2 mL⋅kg⋅min). Participants ingested their habitual diet (HD) (13.1 MJ, 43% [4.6 g⋅kg⋅d] carbohydrate and 38% [1.8 g⋅kg⋅d] fat) or an isoenergetic KD (13.7 MJ, 4% [0.5 g·kg⋅d] carbohydrate and 78% [4 g⋅kg⋅d] fat) from days 0 to 31 (P < 0.001). Participants performed a fasted metabolic test on days -2 and 29 (~25 min) and a run-to-exhaustion trial at 70% V˙O2max on days 0 and 31 following the ingestion of a high-carbohydrate meal (2 g⋅kg) or an isoenergetic low-carbohydrate, high-fat meal (<10 g CHO), with carbohydrate (~55 g⋅h) or isoenergetic fat (0 g CHO⋅h) supplementation during exercise. Training loads were similar between trials and V˙O2max was unchanged (all, P > 0.05). The KD impaired exercise efficiency, particularly at >70% V˙O2max, as evidenced by increased energy expenditure and oxygen uptake that could not be explained by shifts in respiratory exchange ratio (RER) (all, P < 0.05). However, exercise efficiency was maintained on a KD when exercising at <60% V˙O2max (all, P > 0.05). Time-to-exhaustion (TTE) was similar for each dietary adaptation (pre-HD, 237 ± 44 vs post-HD, 231 ± 35 min; P = 0.44 and pre-KD, 239 ± 27 vs post-KD, 219 ± 53 min; P = 0.36). Following keto-adaptation, RER >1.0 vs <1.0 at V˙O2max coincided with the preservation and reduction in TTE, respectively. A 31-d KD preserved mean submaximal exercise capacity in trained endurance athletes without necessitating acute carbohydrate fuelling strategies. However, there was a greater risk of an endurance decrement at an individual level.

Abstract P152: A Personalised Home-Based Physical Activity Intervention for Chronic Heart Failure: Do Physiological Changes Correspond with Patient Experiences?

Background: Referrals to physical activity and exercise programmes for patients with heart failure is suboptimal with high dropout rates in hospital-based programmes. Home-based programmes have gained popularity and help address this issue. The aim of the present study was to explore patients’ experiences of participating in a personalised homebased physical activity intervention programme and to explore whether experiences corresponded with physiological changes post intervention. Methods: Twenty patients (68±7 years) with chronic heart failure (13±11 years) due to reduced ejection fraction underwent a 12-week personalised home-based physical activity programme. This involved increasing daily pedometer step count by 2000 steps from baseline. Patients completed exercise, cardiac function and quality of life tests pre-post intervention. Sixteen of the 20 patients attended one of three focus group discussions to provide their views around the decision to participate in the programme and their experience of the programme when enrolled. Results: Seventeen patients (85%) completed the intervention, and 15 patients achieved the daily target step count which increased from baseline to 3 weeks by 2546 (5108±3064 to 7654±3849, p=0.03), and maintained until week 12 (9022±3942). On completion of the intervention, quality of life improved by 15% (26±18 vs. 22±19), cardiac index and stroke volume increased by 11% and 19% respectively (6.8±1.5 vs. 7.6±2.0 L/min/m2; and 127 ± 34 vs 151 ± 34, P=0.05). Workload and O2 consumption at anaerobic threshold increased by 16% (49±16 vs. 59±14 watts, p=0.01) and 10% (11.5±2.9 vs 12.8±2.2 ml/kg/min). Thematic analyses identified 10 themes influencing participation and maintenance. These included patient’s fear of engaging in physical activity, family influences on engagement with physical activity, support from clinicians and research staff, and increased confidence as a result of participating in a personalised programme. Conclusion: A personalised home-based physical activity intervention programme is feasible and for patients with stable chronic heart failure and led to improved quality of life and submaximal exercise capacity. However, qualitative findings suggest that outcomes are likely to be contingent on personalised feedback and support from suitably trained team members to increase confidence and self-efficacy, family support, and endorsement of the programme from a clinician.

Lifelong burden of small unrepaired atrial septal defect: Results from the Danish National Patient Registry

BackgroundAdult patients with small, unrepaired atrial septal defects (ASD) have higher late mortality than the background population. In this nationwide study, we characterize the late natural history of adults with small, unrepaired ASD. MethodsUsing the Danish National Patient Registry, we included all Danish patients, diagnosed between 1953 and 2011 with an unrepaired ASD. Additionally, all patients, aged 18–65, were invited for clinical testing. Patients also completed a general health survey for comparison with the general population. ResultsWe identified 723 patients with a small unrepaired ASD. Since the time of diagnosis, 182 patients had died, with an average lifespan of 63 years. The most common cause of death was heart failure. Furthermore, ASD patients had a higher burden of chronic disease than the general population (38.2% vs. 26.9%; p = 0.005), particularly lung disease (3.6% vs. 0.9%; p = 0.008). A total of 153 patients (mean age 32 y) underwent additional testing. On echocardiography an open defect was verified in 19.6% (n = 30) of the patients, of which half subsequently underwent intervention. Interestingly, 6-minute walking distance was markedly reduced (p < 0.0001 compared to normative values) no matter whether the defect was open or closed by echocardiography. Finally, 25.5% of the patients often felt stressed or nervous as compared with 16.3% of the general population (p = 0.004). ConclusionsPatients with small, unrepaired ASD in adult life have reduced lifespan, more chronic diseases, impaired submaximal exercise capacity, and higher levels of stress than the general population. The current guidelines for intervention and follow-up may need to be reconsidered.

Effect of a lifestyle-focused electronic patient support application for improving risk factor management, self-rated health, and prognosis in post-myocardial infarction patients: study protocol for a multi-center randomized controlled trial

BackgroundCardiac rehabilitation (CR) programs addressing risk factor management, educational interventions, and exercise contribute to reduce mortality after myocardial infarction (MI). However, the fulfillment of guideline-recommended CR targets is currently unsatisfactory. eHealth, i.e., the use of electronic communication for healthcare, including the use of mobile smartphone applications combined with different sensors and interactive computerized programs, offers a new array of possibilities to provide clinical care. The present study aims to assess the efficacy of a web-based application (app) designed to support persons in adhering to lifestyle advice and medication as a complement to traditional CR programs for improvement of risk factors and clinical outcomes in patients with MI compared with usual care.Methods/designAn open-label multi-center randomized controlled trial is being conducted at different CR centers from three Swedish University Hospitals. The aim is to include 150 patients with MI < 75 years of age who are confident smartphone and/or Internet users. In addition to participation in CR programs according to the usual routine at each center, patients randomized to the intervention arm will receive access to the web-based app. A CR nurse reviews the patients’ self-reported data twice weekly through a medical interface at the clinic. The primary outcome of the study will be change in submaximal exercise capacity (in watts) between 2 and 4 weeks after discharge and when the patient has completed his/her exercise program at the CR center, usually around 3–6 months post-discharge. Secondary outcomes include changes in self-reported physical activity, objectively assessed physical activity by accelerometry, self-rated health, dietary, and smoking habits, body mass index, blood pressure, blood lipids, and glucose/HbA1c levels between inclusion and follow-up visits during the first year post-MI. Additionally, we will assess uptake and adherence to the application, the number of CR staff contacts, and the incidence of cardiovascular events at 1 and 3 years after the MI. Patient recruitment started in 2016, and the first study results are expected in the beginning of 2019.DiscussionThe present study will add evidence to whether electronic communication can be used to improve traditional CR programs for patients after MI.Trial registrationClinicalTrials.gov, NCT03260582. Retrospectively registered on 24 August 2017.