Dietary nitrate supplementation and exercise tolerance in patients with heart failure with reduced ejection fraction.

Endothelial dysfunction and reduced nitric oxide (NO) signaling are key abnormalities leading to skeletal muscle oxygen delivery-utilization mismatch and poor physical capacity in patients with heart failure with reduced ejection fraction (HFrEF). Oral inorganic nitrate supplementation provides an exogenous source of NO that may enhance locomotor muscle function and oxygenation with consequent improvement in exercise tolerance in HFrEF. Thirteen patients (left ventricular ejection fraction ≤40%) were enrolled in a double-blind, randomized crossover study to receive concentrated nitrate-rich (nitrate) or nitrate-depleted (placebo) beetroot juice for 9 days. Low- and high-intensity constant-load cardiopulmonary exercise tests were performed with noninvasive measurements of central hemodynamics (stroke volume, heart rate, and cardiac output via impedance cardiography), arterial blood pressure, pulmonary oxygen uptake, quadriceps muscle oxygenation (near-infrared spectroscopy), and blood lactate concentration. Ten patients completed the study with no adverse clinical effects. Nitrate-rich supplementation resulted in significantly higher plasma nitrite concentration compared with placebo (240 ± 48 vs. 56 ± 8 nM, respectively; P < 0.05). There was no significant difference in the primary outcome of time to exercise intolerance between nitrate and placebo (495 ± 53 vs. 489 ± 58 s, respectively; P > 0.05). Similarly, there were no significant differences in central hemodynamics, arterial blood pressure, pulmonary oxygen uptake kinetics, skeletal muscle oxygenation, or blood lactate concentration from rest to low- or high-intensity exercise between conditions. Oral inorganic nitrate supplementation with concentrated beetroot juice did not present with beneficial effects on central or peripheral components of the oxygen transport pathway thereby failing to improve exercise tolerance in patients with moderate HFrEF.

Translation, cross-cultural adaptation and analysis of the psychometric properties of the lower extremity functional scale (LEFS): LEFS- BRAZIL.

BACKGROUND: There is a lack of questionnaires in Brazilian Portuguese to evaluate patient-reported lower limb function. OBJECTIVE: To translate, cross-culturally adapt to the Brazilian population, and evaluate the psychometric properties of the Lower Extremity Functional Scale (LEFS). METHOD: The LEFS was translated by two independent assessors and back-translated to English. Then, the LEFS-Brazil was tested on 20 patients who answered the questionnaire in the cross-cultural adaptation phase. For the evaluation of the psychometric properties, 100 patients answered the questionnaire. The reliability was tested by two independent assessors. The Medical Outcomes Study 36-item from Health Survey (SF-36) was used as the criterion method for construct validity. The sensitivity to change was tested for four consecutive weeks. RESULTS: The internal consistency was α = 0.96. The intra-observer reliability was CCI (intraclass correlation coefficient) = 0.96 and CCI interobserver = 0.98; the Bland and Altman mean difference (d) intra-observer = -1.52 and d interobserver = 0.46. The correlation between the LEFS and SF-36 in the first week was the following: physical function r=0.82, physical role r=0.57, emotional role r=0.43 and mental health r=0.33. The LEFS was responsive when comparing the mean of the first week to the second, third and fourth weeks and comparing the second to the fourth week. The cut-off point was 11, and the area under the receiving operator curve was 0.96 95% CI [0.88;0.99], with sensitivity = 0.96, 1-specificity = 0 and standard error = 0.02. CONCLUSION: The LEFS-Brazil is reliable, valid and responsive.

Translation, cross-cultural adaptation and analysis of the psychometric properties of the lower extremity functional scale (LEFS): LEFS- BRAZIL

BACKGROUND: There is a lack of questionnaires in Brazilian Portuguese to evaluate patient-reported lower limb function. OBJECTIVE: To translate, cross-culturally adapt to the Brazilian population, and evaluate the psychometric properties of the Lower Extremity Functional Scale (LEFS). METHOD: The LEFS was translated by two independent assessors and back-translated to English. Then, the LEFS-Brazil was tested on 20 patients who answered the questionnaire in the cross-cultural adaptation phase. For the evaluation of the psychometric properties, 100 patients answered the questionnaire. The reliability was tested by two independent assessors. The Medical Outcomes Study 36-item from Health Survey (SF-36) was used as the criterion method for construct validity. The sensitivity to change was tested for four consecutive weeks. RESULTS: The internal consistency was α = 0.96. The intra-observer reliability was CCI (intraclass correlation coefficient) = 0.96 and CCI interobserver = 0.98; the Bland and Altman mean difference () intra-observer = -1.52 and interobserver = 0.46. The correlation between the LEFS and SF-36 in the first week was the following: physical function r=0.82, physical role r=0.57, emotional role r=0.43 and mental health r=0.33. The LEFS was responsive when comparing the mean of the first week to the second, third and fourth weeks and comparing the second to the fourth week. The cut-off point was 11, and the area under the receiving operator curve was 0.96 95% CI [0.88;0.99], with sensitivity = 0.96, 1-specificity = 0 and standard error = 0.02. CONCLUSION: The LEFS-Brazil is reliable, valid and responsive. .