Clinically meaningful change estimates for the six-minute walk test and daily activity in individuals with chronic heart failure. Cardiopulm Phys Ther J. 2013;24:21-29. [PMID: 23997688 DOI: 10.1097/01823246-201324030-00004]

Effect of a 6-month pedometer-based walking intervention on functional capacity in patients with chronic heart failure with reduced (HFrEF) and with preserved (HFpEF) ejection fraction: study protocol for two multicenter randomized controlled trials

Background

Regular physical activity is recommended for patients with chronic heart failure to improve their functional capacity, and walking is a popular, effective, and safe form of physical activity. Pedometers have shown potential to increase the amount of walking across a range of chronic diseases, but it is unknown whether a pedometer-based intervention improves functional capacity and neurohumoral modulation in heart failure patients.

Methods

Two multicenter randomized controlled trials will be conducted in parallel: one in patients with chronic heart failure with reduced ejection fraction (HFrEF), the other in patients with chronic heart failure with preserved ejection fraction (HFpEF). Each trial will consist of a 6-month intervention with an assessment at baseline, at 3 months, at the end of the intervention, and 6 months after completing the intervention. Each trial will aim to include a total of 200 physically inactive participants with chronic heart failure who will be randomly assigned to intervention or control arms. The 6-month intervention will consist of an individualized pedometer-based walking program with weekly step goals, behavioral face-to-face sessions with a physician, and regular telephone calls with a research nurse. The intervention will be based on effective behavioral principles (goal setting, self-monitoring, personalized feedback). The primary outcome is the change in 6-min walk distance at the end of the 6-month intervention. Secondary outcomes include changes in serum biomarkers levels, pulmonary congestion assessed by ultrasound, average daily step count measured by accelerometry, anthropometric measures, symptoms of depression, health-related quality of life, self-efficacy, and MAGGIC risk score.

Discussion

To our knowledge, these are the first studies to evaluate a pedometer-based walking intervention in patients with chronic heart failure with either reduced or preserved ejection fraction. The studies will contribute to a better understanding of physical activity promotion in heart failure patients to inform future physical activity recommendations and heart failure guidelines.

Trial registration The trials are registered in ClinicalTrials.gov, identifiers: NCT03041610, registered 29 January 2017 (HFrEF), NCT03041376, registered 1 February 2017 (HFpEF)

Agreement between heart failure patients and providers in assessing New York Heart Association functional class

BACKGROUND

Uncertainty persists regarding whether patient assessment of New York Heart Association (NYHA) functional classification should be preferred over provider assessment among patients with heart failure (HF).

OBJECTIVES

To compare patient against provider NYHA assessments, and both to distance walked on a 6-minute walk test (6MWT) among patients with HF.

METHODS

In this prospective study, we enrolled 101 HF patients who self-assessed NYHA classification. Health care providers who were blinded to patient ratings of NYHA also rated NYHA. Patients completed a 6MWT according to a standardized protocol. We used Spearman coefficients (rs) to evaluate the correlations between variables.

RESULTS

Patient- and provider-determined NYHA class were poorly correlated, but the relationship was statistically significant (rs = 0.40, p < 0.001). Patients consistently reported better NYHA class (class I: 72% vs 15%) than providers. Provider-determined NYHA had a stronger correlation with 6MWT distance (rs = -0.36, p < 0.001 vs. rs = -0.22, p = 0.03). Providers assigned a worse class to older patients who had comorbidity; patients with dyspnea and longer HF duration assigned themselves a worse class.

CONCLUSION

Patients and providers exhibited poor agreement in NYHA assignment.

Could peak oxygen uptake be estimated from proposed equations based on the six-minute walk test in chronic heart failure subjects?

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Measured and estimated VO₂peak in CHF patients showed a moderate association.

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With the exception of equation 1, all equations underestimated VO₂peak by up to 51%.

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The agreement evaluated using Bland–Altman was not consistent.

Objectives

To evaluate the agreement between the measured peak oxygen uptake (VO₂peak) and the VO₂peak estimated by four prediction equations based on the six-minute walk test (6MWT) in chronic heart failure patients.

Method

Thirty-six chronic heart failure patients underwent cardiopulmonary exercise testing and the 6MWT to assess their VO₂peak. Four previously published equations that include the variable six-minute walk distance were used to estimate the VO₂peak: Cahalin, 1996a (1); Cahalin, 1996b (2); Ross, 2010 (3); and Adedoyin, 2010 (4). The agreement between the VO₂peak in the cardiopulmonary exercise testing and the estimated values was assessed using the Bland–Altman method. A p-value of <0.05 was considered statistically significant.

Results

All estimated VO₂peak values presented moderate correlation (ranging from 0.55 to 0.70; p < 0.001) with measured VO₂peak values. Equations 2, 3, and 4 underestimated the VO₂peak by 30%, 15.2%, and 51.2%, respectively, showing significant differences from the actual VO₂peak measured in the cardiopulmonary exercise testing (p < 0.0001 for all), and the limits of agreement were elevated. The VO₂peak estimated by equation 1 was similar to that measured by the cardiopulmonary exercise testing, and despite the agreement, bias increased as VO₂peak increased.

Conclusions

Only equation 1 showed estimated VO₂peak similar to the measured VO₂peak; however, a large limits of agreement range (∼3 METs) does not allow its use to estimate maximal VO₂peak.

Reliability, construct validity and determinants of 6-minute walk test performance in patients with chronic heart failure

BACKGROUND

In-depth analyses of the measurement properties of the 6-minute walk test (6MWT) in patients with chronic heart failure (CHF) are lacking. We investigated the reliability, construct validity, and determinants of the distance covered in the 6MWT (6MWD) in CHF patients.

METHODS

337 patients were studied (median age 65years, 70% male, ejection fraction 35%). Participants performed two 6MWTs on subsequent days. Demographics, anthropometrics, clinical data, ejection fraction, maximal exercise capacity, body composition, lung function, and symptoms of anxiety and depression were also assessed. Construct validity was assessed in terms of convergent, discriminant and known-groups validity. Stepwise linear regression was used.

RESULTS

6MWT was reliable (ICC=0.90, P<0.0001). The learning effect was 31m (95%CI 27, 35m). Older age (≥65years), lower lung diffusing capacity (<80% predicted) and higher NYHA class (NYHA III) were associated with a lower likelihood of a meaningful increase in the second test (OR 0.45-0.56, P<0.05 for all). The best 6MWD had moderate-to-good correlations with peak exercise capacity (r_s=0.54-0.69) and no-to-fair correlations with body composition, lung function, ejection fraction, and symptoms of anxiety and depression (r_s=0.04-0.49). Patients with higher NYHA classes had lower 6MWD. 6MWD was independently associated with maximal power output during maximal exercise, estimated glomerular filtration rate and age (51.7% of the variability).

CONCLUSION

6MWT was found to be reliable and valid in patients with mild-to-moderate CHF. Maximal exercise capacity, renal function and age were significant determinants of the best 6MWD. These findings strengthen the clinical utility of the 6MWT in CHF.

Exercise- and Psychosocial-Based Interventions to Improve Daily Activity in Heart Failure: A Pilot Study

In individuals with heart failure (HF), low daily activity is associated with a poorer prognosis. The purpose of this pilot study was to investigate the effects of two home-based interventions on the primary HF-related outcome of daily activity and secondary outcomes of exercise tolerance, HF-related health status, and lower extremity functional strength in 16 patients with HF and implanted Medtronic implantable cardioverter defibrillator and cardiac resynchronization devices using a single-blind, randomized controlled pilot trial. Interventions were either daily activity feedback and encouragement or health coaching and home-based exercise. There were no significant differences in primary or secondary outcomes either between or within groups. Three subjects in each treatment group improved in two or more secondary outcomes, and only one improved in daily activity. Although the present pilot study incorporated both exercise and psychosocial components in the intervention, there was no effect on daily activity, perhaps because readiness for behavioral change was not accounted for either in group stratification/allocation or inclusion criteria.

Acute effects of low-level laser therapy irradiation on blood lactate and muscle fatigue perception in hospitalized patients with heart failure-a pilot study

The objective of the present study is to evaluate the acute effects of low-level laser therapy (LLLT) on functional capacity, perceived exertion, and blood lactate in hospitalized patients with heart failure (HF). Patients diagnosed with systolic HF (left ventricular ejection fraction <45 %) were randomized and allocated prospectively into two groups: placebo LLLT group (n = 10)-subjects who were submitted to placebo laser and active LLLT group (n = 10)-subjects who were submitted to active laser. The 6-min walk test (6MWT) was performed, and blood lactate was determined at rest (before LLLT application and 6MWT), immediately after the exercise test (time 0) and recovery (3, 6, and 30 min). A multi-diode LLLT cluster probe (DMC, São Carlos, Brazil) was used. Both groups increased 6MWT distance after active or placebo LLLT application compared to baseline values (p = 0.03 and p = 0.01, respectively); however, no difference was observed during intergroup comparison. The active LLLT group showed a significant reduction in the perceived exertion Borg (PEB) scale compared to the placebo LLLT group (p = 0.006). In addition, the group that received active LLLT showed no statistically significant difference for the blood lactate level through the times analyzed. The placebo LLLT group demonstrated a significant increase in blood lactate between the rest and recovery phase (p < 0.05). Acute effects of LLLT irradiation on skeletal musculature were not able to improve the functional capacity of hospitalized patients with HF, although it may favorably modulate blood lactate metabolism and reduce perceived muscle fatigue.

Ablation Versus Amiodarone for Treatment of Persistent Atrial Fibrillation in Patients With Congestive Heart Failure and an Implanted Device

Background—

Whether catheter ablation (CA) is superior to amiodarone (AMIO) for the treatment of persistent atrial fibrillation (AF) in patients with heart failure is unknown.

Methods and Results—

This was an open-label, randomized, parallel-group, multicenter study. Patients with persistent AF, dual-chamber implantable cardioverter defibrillator or cardiac resynchronization therapy defibrillator, New York Heart Association II to III, and left ventricular ejection fraction <40% within the past 6 months were randomly assigned (1:1 ratio) to undergo CA for AF (group 1, n=102) or receive AMIO (group 2, n=101). Recurrence of AF was the primary end point. All-cause mortality and unplanned hospitalization were the secondary end points. Patients were followed up for a minimum of 24 months. At the end of follow-up, 71 (70%; 95% confidence interval, 60%–78%) patients in group 1 were recurrence free after an average of 1.4±0.6 procedures in comparison with 34 (34%; 95% confidence interval, 25%–44%) in group 2 (log-rank P <0.001). The success rate of CA in the different centers after a single procedure ranged from 29% to 61%. After adjusting for covariates in the multivariable model, AMIO therapy was found to be significantly more likely to fail (hazard ratio, 2.5; 95% confidence interval, 1.5–4.3; P <0.001) than CA. Over the 2-year follow-up, the unplanned hospitalization rate was (32 [31%] in group 1 and 58 [57%] in group 2; P <0.001), showing 45% relative risk reduction (relative risk, 0.55; 95% confidence interval, 0.39–0.76). A significantly lower mortality was observed in CA (8 [8%] versus AMIO (18 [18%]; P =0.037).

Conclusions—

This multicenter randomized study shows that CA of AF is superior to AMIO in achieving freedom from AF at long-term follow-up and reducing unplanned hospitalization and mortality in patients with heart failure and persistent AF.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00729911.

Feasibility of lower-limb muscle power training to enhance locomotor function poststroke

Poststroke motor control is characterized by greatly reduced muscle power generation. To date, the extent to which muscle power limits walking performance or whether its remediation should be a primary component of locomotor rehabilitation has yet to be established. The purpose of this study was to examine the feasibility and the effects of Poststroke Optimization of Walking using Explosive Resistance training, an intervention aimed at improving poststroke muscular and locomotor function. Twelve subjects (6-60 mo poststroke) participated in 24 training sessions (3 sessions/wk for 8 wk). Exercises included leg press, calf raises, and jump training, all performed at high concentric velocity, as well as trials of fast walking. We measured self-selected and fastest comfortable walking speeds as well as knee extensor and plantar flexor strength and power at pretraining, posttraining, and 8 wk follow-up time points. In addition, we also performed a number of clinical assessments commonly used in poststroke rehabilitation trials. Following training, significant improvements in lower-limb muscle strength and power were realized and accompanied by improvements in self-selected as well as fastest comfortable walking speeds. No changes in clinical assessments resulted from training.

Características basales y cambios en el tratamiento tras el periodo de optimización de los pacientes incluidos en el estudio EFICAR

Objetivo

Se describen los datos basales de clase y capacidad funcional, comorbilidades, calidad de vida y cambios en la medicación durante la optimización del tratamiento, en pacientes con insuficiencia cardiaca y función sistólica deprimida (ICFSD) incluidos en el estudio EFICAR.

Diseño

Ensayo clínico aleatorizado multicéntrico.

Emplazamiento

Siete Centros de Salud.

Participantes

Ciento cincuenta pacientes con ICFSD; edad 68 ± 10 años, 77% varones

Mediciones

Variables sociodemográficas e índice de Charlson. Se evaluó la calidad de vida y la capacidad funcional Se realizó optimización del tratamiento.

Resultados

La etiología principal fue la cardiopatía isquémica (45%). Índice de Charlson global: 2,03 ± 1,05. El 31% ingresaron durante el último año por insuficiencia cardiaca. Fracción de eyección media: 37% ± 8. Clase funcional ii: 89%. Capacidad funcional con prueba de esfuerzo: 6,3 ± 1,6. Test 6 min: 446 ± 78 m. Test de la silla: 13,7 ± 4,4 s. Dinamómetro: 34,53 ± 10,12 kgf y 0,58 ± 0,16 bar. Short Form-36 Health Survey: salud física: 43,3 ± 8,4; salud mental: 50,1 ± 10,6. Minnesota Living with Heart Failure Questionnaire global: 22,8 ± 18,7. Tras optimizar el tratamiento no varió el porcentaje de pacientes ni la dosis media de fármacos analizados.

Conclusiones

La mayoría de los sujetos están en clase funcional ii, con capacidad funcional y calidad de vida disminuida e índice de comorbilidad elevado. Un ajuste protocolizado del tratamiento no consigue aumentar la dosis ni el número de pacientes con fármacos eficaces para la insuficiencia cardiaca con función cardiaca deprimida.

Response to Exercise Training and Outcomes in Patients With Heart Failure and Diabetes Mellitus: Insights From the HF-ACTION Trial

BACKGROUND

In HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training), exercise training improved functional capacity in heart failure with reduced ejection fraction (HFrEF). Previous studies have suggested that diabetes mellitus (DM) may be associated with an attenuated response to exercise. We explored whether DM attenuated the improvement in functional capacity with exercise.

METHODS AND RESULTS

HF-ACTION randomized 2331 patients with HFrEF to medical therapy with or without exercise training over a median follow-up of 2.5 years. We examined the interaction between DM and exercise response measured by change in 6-minute walk distance (6MWD) and peak VO2. We also examined outcomes by DM status. In HF-ACTION, 748 (32%) patients had DM. DM patients had lower functional capacity at baseline and had lower exercise volumes at 3 months. There was a significant interaction between DM status and exercise training for change in peak VO2 (interaction P = .02), but not 6MWD. In the exercise arm, DM patients had a smaller mean increase in peak VO2 than non-DM patients (P = .03). There was no interaction between DM and exercise on clinical outcomes. After risk adjustment, DM was associated with increased all-cause mortality/hospitalization (P = .03).

CONCLUSIONS

In HF-ACTION, DM was associated with lower baseline functional capacity, an attenuated improvement in peak VO2, and increased hospitalizations.

Elosulfase Alfa: a review of its use in patients with mucopolysaccharidosis type IVA (Morquio A syndrome)

Elosulfase alfa (Vimizim(®)) is a recombinant form of the human lysosomal enzyme N-acetylgalactosamine-6-sulfatase (GALNS) that is lacking in patients with mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome). It is the first, and currently only, disease-specific treatment option for this very rare, progressively degenerative, autosomal-recessive lysosomal storage disorder. Enzyme replacement therapy with elosulfase alfa aims to restore GALNS activity, thereby preventing the accumulation of keratan sulfate (KS) and chondroitin-6-sulfate in lysosomal compartments of cells that results in the clinical manifestations of MPS IVA. In clinical trials in children and adults with MPS IVA, intravenous elosulfase alfa 2 mg/kg/week provided significant and sustained improvements in urinary levels of KS (a pharmacodynamic biomarker for the disease). In the key placebo-controlled, 24-week, phase 3 trial in patients with MPS IVA aged ≥5 years, elosulfase alfa 2 mg/kg/week significantly improved endurance [least squares mean placebo-adjusted change from baseline in 6-min walk test distance 22.5 m (95 % CI 4.0-40.9)]. Infusion-associated reactions, the primary tolerability issue associated with elosulfase alfa, are generally mild to moderate in severity, self-limiting, and manageable. In the absence of a cure, GALNS enzyme replacement therapy with elosulfase alfa is an important achievement in the treatment of MPS IVA.