ABSTRACT Objective: This study aims to investigate the ability of the six-minute walk distance (6MWD) as a prognostic marker for midterm clinical outcomes three months after coronary artery bypass grafting (CABG), to identify possible predictors of fall in 6MWD in the early postoperative period, and to establish the percentage fall in early postoperative 6MWD, considering the preoperative baseline as 100%. Methods: A prospective cohort of patients undergoing elective CABG were included. The percentage fall in 6MWD was assessed by the difference between preoperative and postoperative day (POD) five. Clinical outcomes were evaluated three months after hospital discharge. Results: There was a significant decrease in 6MWD on POD5 compared with preoperative baseline values (percentage fall of 32.5±16.5%, P<0.0001). Linear regression analysis showed an independent association of the percentage fall of 6MWD with cardiopulmonary bypass (CPB) and preoperative inspiratory muscle strength. Receiver operating characteristic curve analysis revealed that the best cutoff value of percentage fall in 6MWD to predict poorer clinical outcomes at three months was 34.6% (area under the curve = 0.82, sensitivity = 78.95%, specificity = 76.19%, P=0.0001). Conclusion: This study indicates that a cutoff value of 34.6% in percentage fall of 6MWD on POD5 was able to predict poorer clinical outcomes at three months of follow-up after CABG. Use of CPB and preoperative inspiratory muscle strength were independent predictors of percentage fall of 6MWD in the postoperative period. These findings further support the clinical application of 6MWD and propose an inpatient preventive strategy to guide clinical management over time.

ABSTRACT Objective: This study aims to investigate the ability of the six-minute walk distance (6MWD) as a prognostic marker for midterm clinical outcomes three months after coronary artery bypass grafting (CABG), to identify possible predictors of fall in 6MWD in the early postoperative period, and to establish the percentage fall in early postoperative 6MWD, considering the preoperative baseline as 100%. Methods: A prospective cohort of patients undergoing elective CABG were included. The percentage fall in 6MWD was assessed by the difference between preoperative and postoperative day (POD) five. Clinical outcomes were evaluated three months after hospital discharge. Results: There was a significant decrease in 6MWD on POD5 compared with preoperative baseline values (percentage fall of 32.5±16.5%, P<0.0001). Linear regression analysis showed an independent association of the percentage fall of 6MWD with cardiopulmonary bypass (CPB) and preoperative inspiratory muscle strength. Receiver operating characteristic curve analysis revealed that the best cutoff value of percentage fall in 6MWD to predict poorer clinical outcomes at three months was 34.6% (area under the curve = 0.82, sensitivity = 78.95%, specificity = 76.19%, P=0.0001). Conclusion: This study indicates that a cutoff value of 34.6% in percentage fall of 6MWD on POD5 was able to predict poorer clinical outcomes at three months of follow-up after CABG. Use of CPB and preoperative inspiratory muscle strength were independent predictors of percentage fall of 6MWD in the postoperative period. These findings further support the clinical application of 6MWD and propose an inpatient preventive strategy to guide clinical management over time.

RESUMO Introdução O teste AVD-Glittre é um teste submáximo que envolve atividades de sentar/levantar, subir/descer degraus e sustentação de pesos, que tem grande potencial de uso na avaliação da intolerância ao esforço na insuficiência cardíaca. Objetivos Pesquisar a influência da insuficiência cardíaca na capacidade física máxima (teste ergométrico - TE) e funcional (TC6 e teste AVD-Glittre), na força dos músculos respiratórios (PImáx e PEmáx) e periféricos (força de preensão palmar) e estudar a correlação entre as variáveis avaliadas. Métodos Estudo prospectivo comparativo que avaliou 44 indivíduos divididos em dois grupos: G1, com 26 cardiopatas (20 homens/ 6 mulheres, 65,26 ± 8,50 anos) e G2 com 18 indivíduos saudáveis pareados com o G1 quanto à distribuição de sexo, idade e características antropométricas (10 homens/8 mulheres, 60,72 ± 8,39 anos). A comparação das variáveis categóricas foi realizada pelo teste do qui-quadrado e a das variáveis contínuas, pelo teste t de Student ou Mann-Whitney. O estudo da correlação entre variáveis foi feito pelo índice de Pearson para PEmáx e força de preensão palmar; para as demais, pelo índice de correlação de Spearman, com nível de significância estatístico de 5%. Resultados Os grupos foram homogêneos quanto à distribuição de sexo, idade e características antropométricas. O G1 apresentou pior desempenho em todos os testes: TE (p = 0,016), AVD-Glittre (p = 0,001), TC6’ (p = 0,001), PImáx (p = 0,012), PEmáx (p = 0,007) e força de preensão palmar (p = 0,036). Houve correlação negativa entre AVD-Glittre e TC6 e AVD-Glittre e força de preensão palmar em G1. Conclusão A insuficiência cardíaca resultou em comprometimento da capacidade física máxima, funcional e da força muscular respiratória e periférica, com correlação negativa entre capacidade funcional e força de preensão palmar. Nível de Evidência II; Estudo Prospectivo e Comparativo.

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

RESUMEN Introducción La prueba AVD-Glittre es una prueba submáxima que implica sentarse/pararse, subir/bajar escalones y actividades con carga de peso, que tiene un gran potencial para uso en la evaluación de la intolerancia al estrés en la insuficiencia cardíaca. Objetivos Investigar la influencia de la insuficiencia cardíaca en la capacidad física máxima (prueba ergométrica - PE) y funcional (prueba 6MWT y AVD-Glittre), en la fuerza de los músculos respiratorios (PImáx y PEmáx) y periféricos (fuerza de agarre manual) y estudiar la correlación entre las variables evaluadas. Métodos Estudio prospectivo comparativo que evaluó a 44 individuos, divididos en dos grupos: G1, con 26 cardíacos (20 hombres/6 mujeres, 65,26 ± 8,50 años) y G2 con 18 individuos sanos emparejados con G1 con respecto a la distribución de sexo, edad y características antropométricas (10 hombres/8 mujeres, 60,72 ± 8,39 años). La comparación de las variables categóricas se realizó utilizando la prueba de chi-cuadrado y la de variables continuas, utilizando la prueba t de Student o Mann-Whitney. El estudio de la correlación entre variables se realizó utilizando el índice de Pearson para PEmáx y fuerza de agarre manual; para las demás, se utilizó el índice de correlación de Spearman, con un nivel de significación estadística del 5%. Resultados Los grupos fueron homogéneos en cuanto a la distribución por sexo, edad y características antropométricas. El G1 presentó el peor desempeño en todas las pruebas: PE (p = 0,016), AVD-Glittre (p = 0,001), 6MWT (p = 0,001), PImáx (p = 0,012), PEmáx (p = 0,007) y fuerza de agarre manual (p = 0,036). Hubo una correlación negativa entre AVD-Glittre y 6MWT y AVD-Glittre y la fuerza de agarre manual en G1. Conclusión La insuficiencia cardíaca resultó en un deterioro de la fuerza muscular máxima, funcional y respiratoria y periférica, con una correlación negativa entre la capacidad funcional y la fuerza de agarre manual. Nivel de Evidencia II; Estudio Prospectivo y Comparativo.