Estimation of Maximal Work Rate Based on the 6-Minute Walk Test and Fat-Free Mass in Chronic Obstructive Pulmonary Disease

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Do muscle strengthening exercises improve performance in the 6-minute walk test in postmenopausal women?

Background: Walking speed seems to be related to aerobic capacity, lower limb strength, and functional mobility, however it is not clear whether there is a direct relationship between improvement in muscle strength and gait performance in early postmenopausal women. Objective: To evaluate the effect of muscle strengthening exercises on the performance of the 6-minute walk test in women within 5 years of menopause. Methods: The women were randomized into control group (n=31), which performed no exercise, and exercise group (n=27), which performed muscle strengthening exercises. The exercises were performed twice a week for 3 months. The exercise protocol consisted of warm-up, stretching, and strengthening of the quadriceps, hamstring, calf, tibialis anterior, gluteus maximus, and abdominal muscles, followed by relaxation. Muscular strength training started with 60% of 1MR (2 series of 10-15 repetitions), reaching 85% until the end of the 3-month period (4 series of 6 repetitions each). Results: The between-group comparisons pre- and post-intervention did not show any difference in distance walked, heart rate or blood pressure (p>0.05), but showed differences in muscle strength post-intervention, with the exercise group showing greater strength (p<0.05). In the within-group comparison, there were differences in final heart rate and quadriceps and hamstring strength pre- and post-intervention in the exercise group (p<0.05). Conclusion: The results suggest that muscle strengthening of the lower limbs did not improve performance in the 6-minute walk test in this population of postmenopausal women. Trial registration ACTRN12609001053213.

The utility of preoperative six-minute-walk distance in lung transplantation

RATIONALE The use of 6-minute-walk distance (6MWD) as an indicator of exercise capacity to predict postoperative survival in lung transplantation has not previously been well studied. OBJECTIVES To evaluate the association between 6MWD and postoperative survival following lung transplantation. METHODS Adult, first time, lung-only transplantations per the United Network for Organ Sharing database from May 2005 to December 2011 were analyzed. Kaplan-Meier methods and Cox proportional hazards modeling were used to determine the association between preoperative 6MWD and post-transplant survival after adjusting for potential confounders. A receiver operating characteristic curve was used to determine the 6MWD value that provided maximal separation in 1-year mortality. A subanalysis was performed to assess the association between 6MWD and post-transplant survival by disease category. MEASUREMENTS AND MAIN RESULTS A total of 9,526 patients were included for analysis. The median 6MWD was 787 ft (25th-75th percentiles = 450-1,082 ft). Increasing 6MWD was associated with significantly lower overall hazard of death (P < 0.001). Continuous increase in walk distance through 1,200-1,400 ft conferred an incremental survival advantage. Although 6MWD strongly correlated with survival, the impact of a single dichotomous value to predict outcomes was limited. All disease categories demonstrated significantly longer survival with increasing 6MWD (P ≤ 0.009) except pulmonary vascular disease (P = 0.74); however, the low volume in this category (n = 312; 3.3%) may limit the ability to detect an association. CONCLUSIONS 6MWD is significantly associated with post-transplant survival and is best incorporated into transplant evaluations on a continuous basis given limited ability of a single, dichotomous value to predict outcomes.

Does the 6-minute walk test predicts functional capacity in a sample of elderly women? A pilot study

Introduction: Functional capacity is the capacity to conduct daily activities in an independent way. It can be estimated with the 6-minutes’ walk test (6MWT) and other validated functional tests. Objectives: Verify associations between functional capacity measured with two different instruments (6MWT and Composite Physical Function (CPF) scale) and levels of physical activity and between those and characterization variables. Methods: This sample consisted of 30 apparently healthy elderly women from Loures municipality. Essentially they should be independent and community-dwelling. Characterization data were collected, containing characterization of physical activity levels and anthropometric data. Functional capacity was assessed with CPF scale and distance walked by the 6MWT. Results were analysed using a SPSS v21.0 through correlation tests. Results: The walked distance in 6MWT was positively associated with height (r = 0.406; p = 0.026), physical activity level (r = 0.594; p = 0.001) and functional capacity (r = 0.682; p = 0.000). For each point more obtained in CPF, the distance walked increases on average by 7.5 meters. Relatively to sedentary participants, being insufficiently active increases, on average, the distance walked in 85.8 meters; and being active increases, on average, the distance walked in 108.8 meters. No other associations were observed in our sample. Conclusion: Based on the collected sample, walked distance in 6MWT has a high correlation with results in CPF scale, so this test can be used to predict functional capacity. More attention should be taken to promote strategies to increase walking in older adults.

Predicted VO2 on 6 minutes walk test for FAP liver transplanted patients

Physical function is limited post-liver transplantation and exercise training can improve exercise capacity following transplantation but previously assessment of functional capacity is necessary. The 6 minute walk test (6MWT) is routinely used for studying patient’s exercise capacity and is less expensive and time consuming than a Cardiopulmonary Exercise Test (CPXT). There have been some studies looking at the relationship between 6MWT and peak VO2 in patients but few presented an adequate equation for predicted peak VO2 from 6MWT to transplanted patients and none for Familial Amyloidotic Polyneuropathy (FAP) liver transplanted patients (FAPTx). The aim of this study was to compare the validity of 6 equations as predictors of VO2 from the 6MWT and compare it with directly measured VO2 in patients FAPTx.

Does 6-minutes walk test predict functional capacity in elderly people?

Portugal has an accentuated aging tendency, presenting an elderly population (individuals with more than 65 years old) of 19.2%. The average life expectancy is 79.2 years. Thus, it’s important to maintain autonomy and independency as long as possible. Functional ability concept rises from the need to evaluate the capacity to conduct daily activities in an independent way. It can be estimated with the 6-minute walk test (6MWT) and other validated test. This test is simple, reliable, valid and consists in a daily activity (walk). The goals of this study was to verify associations between functional capacity measured with two different instruments (6MWT and Composite Physical Function (CPF) scale) and between those results and characterization variables.

Comparaison de la performance à l’exercice de patients souffrant d’insuffisance cardiaque sévère à une épreuve d’effort maximal, une épreuve sous-maximale et un test de marche

L’insuffisance cardiaque est une pathologie provoquant une diminution importante des capacités fonctionnelles des patients ainsi qu’une diminution drastique de la qualité de vie. L’évaluation des capacités fonctionnelles est généralement effectuée par une épreuve d’effort maximal. Cependant pour plusieurs patients, cet effort est difficile à compléter. Les objectifs de l’étude présentée dans ce mémoire sont : (1) valider trois méthodes d’évaluation de la capacité fonctionnelle et aérobie des sujets souffrant d’insuffisance cardiaque avec un complexe QRS élargi; (2) chercher à établir le profil des patients démontrant une meilleure tolérance à l’exercice malgré une consommation maximale d’oxygène identique; et (3) démontrer les conséquences de la présence et de la magnitude de l’asynchronisme cardiaque dans la capacité fonctionnelle et la tolérance à l’exercice. Tous les sujets ont été soumis à un test de marche de six minutes, un test d’endurance à charge constante sur tapis roulant et à une épreuve d’effort maximal avec mesure d’échanges gazeux à la bouche. Les résultats ont montré une association significative entre les épreuves maximale et plus spécifiquement sous-maximale. De plus, une meilleure tolérance à l’exercice serait associée significativement à une plus grande masse du ventricule gauche. Finalement, les résultats de notre étude n’ont pas montré d’effet d’un asynchronisme cardiaque sur la performance à l’effort tel qu’évalué par nos protocoles.

Comparison between actual and predicted postoperative stair-climbing test, walk test and spirometric values in patients undergoing lung resection

OBJETIVO: Verificar se os testes: Volume Expiratório Forçado no 1º segundo (VEF1), Teste de Caminhada de 6 minutos (TC6) e Teste de Escada (TE) se alteram proporcionalmente ao pulmão funcionante ressecado. MÉTODOS: Foram incluídos pacientes candidatos a toracotomia para ressecção pulmonar. No pré-operatório (pré) e no mínimo três meses após a cirurgia (pós), realizaram espirometria, TC6 e TE. O TE foi realizado em escada com 12,16m de altura. O tempo para subir todos os degraus o mais rápido possível foi chamado tempo de escada (tTE). Os cálculos dos valores dos testes preditos para o pós-operatório (ppo) foram realizados conforme o número de segmentos funcionantes perdidos. Os valores pré, ppo e pós foram comparados entre si para cada teste. Estatística: foi utilizada a análise de variância para medidas repetidas (ANOVA), com significância de 5%. RESULTADOS: Foram estudados 40 pacientes. A ressecção pulmonar variou desde o ganho de dois segmentos funcionantes até a perda de 9. Os valores pré, ppo e pós foram respectivamente: VEF1 -pré = 2,6±0,8L, ppo = 2,3±0,8L, pós = 2,3±0,8L (VEF1pré > VEF1ppo = VEF1pós), TC6-pré = 604±63m, ppo = 529±103m, pós = 599±74m (TC6pré = TC6pós > TC6ppo), tTE-pré = 32,9±7,6s, ppo = 37,8±12,1s, pós = 33,7±8,5s (tTEpré = tTEpós < tTEppo). CONCLUSÃO: Nas ressecções pulmonares, este grupo de pacientes perdeu função pulmonar medida através da espirometria, mas não perdeu a capacidade de exercício, medida através dos testes de escada e caminhada.

Shwachman-Kulczycki score still useful to monitor cystic fibrosis severity

INTRODUCTION: The Shwachman-Kulczycki score was the first scoring system used in cystic fibrosis to assess disease severity. Despite its subjectivity, it is still widely used. OBJECTIVE: To study correlations among forced expiratory volume in one second (FEV1), chest radiography, chest computed tomography, 6-minute walk test, and Shwachman-Kulczycki score in patients with cystic fibrosis and to test whether the Shwachman-Kulczycki score is still useful in monitoring the severity of the disease. METHODS: A cross-sectional prospective study was performed to analyze the correlations (Spearman). Patients with clinically stable cystic fibrosis, aged 3-21 years, were included. RESULTS: 43 patients, 19F/24M, mean age 10.5 + 4.7 years, with a median Shwachman-Kulczycki score of 70 were studied. The median Brasfield and Bhalla scores were 17 and 10, respectively. The mean Z score for the 6-minute walk test was -1.1 + 1.106 and the mean FEV1 was 59 + 26 (as percentage of predicted values). The following significant correlations versus the Shwachman-Kulczycki score were found: FEV1 (r = 0.76), 6-minute walk test (r = 0.71), chest radiography (r = 0.71) and chest computed tomography (r = -0.78). When patients were divided according to FEV1, a statistically significantly correlation with the Shwachman-Kulczycki score was found only in patients with FEV1 <70% (r = 0.67). CONCLUSIONS: The Shwachman-Kulczycki score remains an useful tool for monitoring the severity of cystic fibrosis, adequately reflecting the functional impairment and chest radiography and tomography changes, especially in patients with greater impairment of lung function. When assessing patients with mild lung disease its limitations should be considered and its usefulness in such patients should be evaluated in larger populations.

Body composition, muscle strength, functional capacity, and physical disability risk in liver transplanted familial amyloidotic polyneuropathy patients

Abstract: Background: Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disease leading to sensory and motor polyneuropathies, and functional limitations. Liver transplantation is the only treatment for FAP, requiring medication that negatively affects bone and muscle metabolism. The aim of this study was to compare body composition, levels of specific strength, level of physical disability risk, and functional capacity of transplanted FAP patients (FAPTx) with a group of healthy individuals (CON). Methods: A group of patients with 48 FAPTx (28 men, 20 women) was compared with 24 CON individuals (14 men, 10 women). Body composition was assessed by dual-energy X-ray absorptiometry, and total skeletal muscle mass (TBSMM) and skeletal muscle index (SMI) were calculated. Handgrip strength was measured for both hands as was isometric strength of quadriceps. Muscle quality (MQ) was ascertained by the ratio of strength to muscle mass. Functional capacity was assessed by the six-minute walk test. Results: Patients with FAPTx had significantly lower functional capacity, weight, body mass index, total fat mass, TBSMM, SMI, lean mass, muscle strength, MQ, and bone mineral density. Conclusion: Patients with FAPTx appear to be at particularly high risk of functional disability, suggesting an important role for an early and appropriately designed rehabilitation program.

Efeito de um programa de exercício em indivíduos com patologia cardíaca: serie de estudos de caso

Sendo, o exercício físico uma parte importante na Reabilitação de pacientes com patologia cardíaca, o presente estudo tem por Objectivo: verificar se um programa de exercícios aeróbios, mesmo quando associadas a patologias crónicas poderão ter efeito nas variáveis da capacidade funcional, ansiedade e depressão e qualidade de vida. Tipo de estudo: série de estudos de caso prospectivo. Métodos: O programa de exercício realizou-se em 8 semanas tendo cada um dos doentes cardíacos sido avaliados no início do plano e no fim das 8 semanas sobre os seguintes aspectos: a composição corporal (massa magra, massa gorda, Taxa metabólica basal e água), o teste dos 6 minutos de marcha, em termos de ansiedade /depressão e percepção do estados de saúde. Resultados: Em relação à composição corporal, destacase a perda de peso no caso clínico 4 com uma variação de -4.54%; aumento de massa magra de 46.6% e uma diminuição de massa gorda de -41 .1% no caso clínico 2 e um aumento de 4,78% da taxa de metabolismo basal no caso clínico 1 . Na capacidade funcional de exercício houve uma variação média positiva de 16,8% na distância percorrida; verifica-se também um aumento gradual de tempo de exercício ao longo das 8 semanas de tratamento. Por último, uma variação média negativa nos níveis de ansiedade de -28,5% e depressão de -40%; um aumento de 30% na percepção subjectiva do estado de saúde nos 4 casos clínicos deste estudo. Conclusão: O programa de exercícios teve efeitos positivos nos 4 casos clínicos estudados. No entanto, pelas características individuais de cada caso, os seus efeitos tiveram impacto diferente em cada caso, devendo por isso, ser prescrito exercício de forma individualizada.

Factors associated to quality of life in active elderly

OBJECTIVE: To analyze whether quality of life in active, healthy elderly individuals is influenced by functional status and sociodemographic characteristics, as well as psychological parameters. METHODS: Study conducted in a sample of 120 active elderly subjects recruited from two open universities of the third age in the cities of São Paulo and São José dos Campos (Southeastern Brazil) between May 2005 and April 2006. Quality of life was measured using the abbreviated Brazilian version of the World Health Organization Quality of Live (WHOQOL-bref) questionnaire. Sociodemographic, clinical and functional variables were measured through crossculturally validated assessments by the Mini Mental State Examination, Geriatric Depression Scale, Functional Reach, One-Leg Balance Test, Timed Up and Go Test, Six-Minute Walk Test, Human Activity Profile and a complementary questionnaire. Simple descriptive analyses, Pearson's correlation coefficient, Student's t-test for non-related samples, analyses of variance, linear regression analyses and variance inflation factor were performed. The significance level for all statistical tests was set at 0.05. RESULTS: Linear regression analysis showed an independent correlation without colinearity between depressive symptoms measured by the Geriatric Depression Scale and four domains of the WHOQOL-bref. Not having a conjugal life implied greater perception in the social domain; developing leisure activities and having an income over five minimum wages implied greater perception in the environment domain. CONCLUSIONS: Functional status had no influence on the Quality of Life variable in the analysis models in active elderly. In contrast, psychological factors, as assessed by the Geriatric Depression Scale, and sociodemographic characteristics, such as marital status, income and leisure activities, had an impact on quality of life.

Factores que influenciam a actividade física na vida diária dos doentes com doença pulmonar obstrutiva crónica

RESUMO: A monitorização da actividade física diária nos doentes com Doença Pulmonar Obstrutiva Crónica (DPOC) tem sido alvo de grande interesse nos últimos tempos. No entanto, ainda nenhum estudo reuniu o conjunto de factores – grau de obstrução, hiperinsuflação pulmonar, alteração das trocas gasosas, dispneia, dessaturação de oxigénio, capacidade de exercício, ansiedade e depressão – que podem afectar a sua realização, nem os correlacionou com os dados obtidos com o pedómetro e que reflectem o que cada doente realmente faz no seu dia-adia. O presente estudo teve como objectivo principal identificar os factores que influenciam a actividade física na vida diária dos doentes com DPOC. Estudaram-se 55 doentes do sexo masculino com idade média de 67 anos e um FEV1 médio de 50,8% do previsto, com DPOC moderada a muito grave (estadios II a IV), de entre os utentes do Laboratório de Fisiopatologia Respiratória do Centro Hospitalar de Torres Vedras. Avaliaram-se os parâmetros da escala de dispneia modificada do Medical Research Council (MMRC), escala London Chest Activity of Daily Living (LCADL), escala de Ansiedade e Depressão Hospitalar (HADS), índice BODE, estudo funcional respiratório em repouso, teste de marcha de seis minutos e o número de passos por dia utilizando um pedómetro por um período de três dias. Observou-se que os doentes deram em média 4972 passos por dia e apresentaram uma cotação total média de 17,7 na LCADL, tendo existido diferenças estatisticamente significativas em função da gravidade da doença, sendo que os doentes mais graves são os que em média andam menos no seu dia-a-dia e apresentam maior limitação na realização das actividades de vida diária. O número de passos por dia apresentou correlações significativas com as variáveis idade, dispneia, depressão, hiperinsuflação monar, gravidade de obstrução (FEV1), trocas gasosas (DLCO), saturação arterial de oxigénio mínima e correlação mais forte com a distância percorrida no TM6m. Este estudo permitiu identificar que os factores determinantes da actividade física na vida diária de doentes com DPOC nos estadios II a IV, foram a dispneia e a distância percorrida no TM6m. Além disso, estes doentes constituem um grupo sedentário, particularmente a partir do estadio III, com níveis de actividade física diária baixos.-----------ABSTRACT There has been an increased interest in monitoring the daily physical activity in patients with Chronic Obstructive Pulmonary Disease (COPD). However, no specific study has been realized so far that has put the different factors which can affect the results obtained altogether, (such as the degree of obstruction, pulmonary hyperinflation, abnormal gas exchange, dyspnea, oxygen desaturation, exercise capacity, anxiety and depression) or correlated with data obtained from the pedometer, which reflect each patient actual activity in their daily life. This study aimed to identify the main factors that influence physical activity in daily life of patients with COPD. The scope of this study was 55 male patients with an average age of 67 years old and an average FEV1 of 50.8% predicted, with moderate to severe COPD (stages II to IV), among patients from the Respiratory Pathophysiology Laboratory of the Centro Hospitalar de Torres Vedras. Were evaluated the parameters of the modified Medical Research Council dyspnea scale (MMRC), London Chest Activity of Daily Living scale (LCADL), Hospital Anxiety and Depression scale (HADS), BODE index, pulmonary function test at rest, six minute walk test (6MWT) and the number of steps per day using a pedometer for a period of three days. It was observed that patients have walked an average of 4972 steps per day and had a total score of 17.7 at LCADL, and statistically significant differences were stated depending on the severity of the disease. Whereas patients with a more severe degree of the disease have walked least in their daily life and show greater restraint in carrying out activities of daily living. The number of steps per day showed significant correlations with age, dyspnea, depression, lung hyperinflation, severity of obstruction (FEV1), gas exchange (DLCO), minimum arterial oxygen saturation and stronger correlation with distance walked on 6MWT. This study shows that the crucial factors of physical activity in daily life of COPD patients at stages II to IV were dyspnea and distance on 6MWT. Moreover, these patients constitute a sedentary group, particularly from the stage III, with lower levels of daily physical activity.

Reabilitação respiratória na DPOC : efeito de duas intensidades de treino de exercício aeróbio nos resultados centrados no doente

RESUMO: Introdução: O treino de exercício assume uma importância fundamental nos programas de reabilitação respiratória, contudo permanece desconhecida qual a intensidade de treino efectiva na mudança dos resultados centrados no doente. Objectivos: Foram estudados os efeitos de duas intensidades de treino aeróbio na qualidade de vida relacionada com a saúde, no controlo de sintomas e na tolerância ao exercício, num programa de reabilitação respiratória para doentes com DPOC. Métodos: Trinta e quatro doentes com DPOC de estádios GOLD de ligeiro a muito grave, foram alocados aleatoriamente a intensidades de treino de exercício aeróbio de 60% ou 80% da intensidade máxima avaliada na prova de esforço num programa ambulatório de reabilitação respiratória de 20 sessões. Foram avaliados resultados centrados no doente pela aplicação do questionário respiratório de St.George, do índice de dispneia de Mahler, do questionário de actividades da vida diária do London Chest, da prova de 6 minutos, da prova de endurance a carga constante e da prova de esforço máxima incremental. Resultados: Apesar de existirem melhorias significativas em todos os resultados para ambos os grupos, a diferença média intergrupal por efeito da intensidade de treino aeróbio a 60% ou 80% da carga máxima em prova de esforço não foi significativa no questionário respiratório de St.George (p=0,306), no índice de dispneia de Mahler (p=0,378), no questionário de actividades da vida diária do London Chest (p=0,425), na prova de marcha de 6 minutos (p=0,917), na prova de endurance a carga constante (p=0,504) e na prova de esforço máxima incremental (p=0,117). Verificou-se ainda que a média das diferenças intergrupais na prova de endurance a carga constante e na prova de marcha de 6 minutos não apresentou qualquer associação com a idade dos doentes. Conclusões: O estudo permite concluir que não existem diferenças significativas nas alterações médias da qualidade de vida relacionada com a saúde, do controle de sintomas e da tolerância ao exercício em doentes com DPOC como efeito de duas intensidades de treino aeróbio. Os autores propõem para a prática clínica em reabilitação respiratória, a aplicação de intensidades de treino aeróbio individualmente adaptadas, de pelo menos 60% da carga máxima na prova de esforço inicial. -------------------------------ABSTRACT: Introduction: Exercise training is an important component of pulmonary rehabilitation, but it remains questionable as how training intensity changes patient-centered outcomes. Aims and objectives: The effects of two aerobic exercise training intensities in health-related quality of life, symptoms control and exercise tolerance in COPD patients were studied. Methods: Thirty-four COPD patients from mild to very severe GOLD stages were randomly assigned to a 60% or 80% aerobic exercise training intensity in a twenty-session outpatient pulmonary rehabilitation program. Patient-centered outcomes were assessed with St.George's respiratory questionnaire, Mahler dyspnoea index, London Chest activity of daily living, six minute walk test, constant work rate test and maximal incremental test. Results: Although there were significant improvements in all outcomes for both groups, there were no differences in mean change in St.George's respiratory questionnaire (p=0,306), Mahler dyspnoea index (p=0,378), London Chest activity of daily living (p=0,917), six-minute walk test (p=0,504), constant work rate test (p=0,504) and maximal incremental test (p=0,117), as an effect of aerobic exercise training intensity of 60% or 80%. Mean changes in constant work rate and six-minute walk test were not age-related. Conclusions: It is concluded that there are no differences in mean changes in health-related quality of life, symptoms control and exercise tolerance in COPD patients as an effect of two aerobic exercise training intensities. Therefore, the authors suggest that individually tailored exercise intensities above 60% should guide clinical practice in pulmonary rehabilitation.

Percutaneous Treatment of Mitral Valve Regurgitation: Initial Experience with the MitraClip Device

INTRODUCTION: Mitral regurgitation (MR) is the most common valvular disease and has recently become the target of a number of percutaneous approaches. The MitraClip is virtually the only device for which there is considerable experience, with more than 20,000 procedures performed worldwide. OBJECTIVE: To describe our initial experience of the percutaneous treatment of MR with the MitraClip device. METHODS: We describe the first six MitraClip cases performed in this institution (mean age 58.5 ± 13.1 years), with functional MR grade 4+ and New York Heart Association (NYHA) heart failure class III or IV (n=3), with a mean follow-up of 290 ± 145 days. RESULTS: Procedural success (MR ≤ 2+) was 100%. Total procedure time was 115.8 ± 23.7 min, with no in-hospital adverse events and discharge between the fourth and eighth day, and consistent improvement in the six-minute walk test (329.8 ± 98.42 vs. 385.33 ± 106.95 m) and in NYHA class (three patients improved by two NYHA classes). During follow-up there were two deaths, in two of the four patients who had been initially considered for heart transplantation. CONCLUSION: In patients with functional MR the MitraClip procedure is safe, with both a high implantation and immediate in-hospital success rate. A longer follow-up suggests that the clinical benefit decreases or disappears completely in patients with more advanced heart disease, namely those denied transplantation or on the heart transplant waiting list.