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BACKGROUND: This is the first study to investigate the performance of 6MST in COPD patients divided into different symptom severity groups based on the CAT questionnaire score. OBJECTIVES: To evaluate the relationship between the degree symptomatology using the chronic obstructive pulmonary disease (COPD) Assessment Test (CAT) with the six- minute step test (6MST) in COPD patients. METHODS: This is a cross-sectional study in which 59 patients with COPD were evaluated. The groups were stratified according to the subsequent cutoff points: CAT <10 (little impact) n= 22; CAT 11-20 (moderate impact) n=20; CAT <20 (large impact) n=17. During 6MST the individuals were instructed to go up and down a single step with a height of 20 centimeters (cm). RESULTS: Comparing the groups in relation to performance on the 6MST, the number of climbs on the step were significantly higher in the CAT group <10 when compared to the CAT group >20, the variation in HR between rest and peak exercise (∆ HRpeak- rest) was lower in the CAT>20 group compared to the CAT<10 group and the CAT 11- 20 group. We found direct relationships between the number of ascents and descents in the 6MST vs the CAT score (r=0.35, p=0.007); and 6MST vs degree of obstruction of %FEV1 (r-0.46, p=0.002) We verified a linear regression model in which the FEV1 (L) and the CAT score influenced 29% in the performance of the 6MST. CONCLUSION: The COPD severity represented by the FEV1 and the CAT score are associated and influenced by 29% the performance of 6-minute step test. Our findings may have important implications for the clinical evaluation of these patients as well as for rehabilitation.
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Prueba de Esfuerzo , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Estudios Transversales , Pruebas de Función Respiratoria , Ejercicio FísicoRESUMEN
Our aim was to evaluate: (1) the prevalence of coexistence of heart failure (HF) and chronic obstructive pulmonary disease (COPD) in the studied patients; (2) the impact of HF + COPD on exercise performance and contrasting exercise responses in patients with only a diagnosis of HF or COPD; and (3) the relationship between clinical characteristics and measures of cardiorespiratory fitness; (4) verify the occurrence of cardiopulmonary events in the follow-up period of up to 24 months years. The current study included 124 patients (HF: 46, COPD: 53 and HF + COPD: 25) that performed advanced pulmonary function tests, echocardiography, analysis of body composition by bioimpedance and symptom-limited incremental cardiopulmonary exercise testing (CPET) on a cycle ergometer. Key CPET variables were calculated for all patients as previously described. The [Formula: see text]E/[Formula: see text]CO2 slope was obtained through linear regression analysis. Additionally, the linear relationship between oxygen uptake and the log transformation of [Formula: see text]E (OUES) was calculated using the following equation: [Formula: see text]O2 = a log [Formula: see text]E + b, with the constant 'a' referring to the rate of increase of [Formula: see text]O2. Circulatory power (CP) was obtained through the product of peak [Formula: see text]O2 and peak systolic blood pressure and Ventilatory Power (VP) was calculated by dividing peak systolic blood pressure by the [Formula: see text]E/[Formula: see text]CO2 slope. After the CPET, all patients were contacted by telephone every 6 months (6, 12, 18, 24) and questioned about exacerbations, hospitalizations for cardiopulmonary causes and death. We found a 20% prevalence of HF + COPD overlap in the studied patients. The COPD and HF + COPD groups were older (HF: 60 ± 8, COPD: 65 ± 7, HF + COPD: 68 ± 7). In relation to cardiac function, as expected, patients with COPD presented preserved ejection fraction (HF: 40 ± 7, COPD: 70 ± 8, HF + COPD: 38 ± 8) while in the HF and HF + COPD demonstrated similar levels of systolic dysfunction. The COPD and HF + COPD patients showed evidence of an obstructive ventilatory disorder confirmed by the value of %FEV1 (HF: 84 ± 20, COPD: 54 ± 21, HF + COPD: 65 ± 25). Patients with HF + COPD demonstrated a lower work rate (WR), peak oxygen uptake ([Formula: see text]O2), rate pressure product (RPP), CP and VP compared to those only diagnosed with HF and COPD. In addition, significant correlations were observed between lean mass and peak [Formula: see text]O2 (r: 0.56 p < 0.001), OUES (r: 0.42 p < 0.001), and O2 pulse (r: 0.58 p < 0.001), lung diffusing factor for carbon monoxide (DLCO) and WR (r: 0.51 p < 0.001), DLCO and VP (r: 0.40 p: 0.002), forced expiratory volume in first second (FEV1) and peak [Formula: see text]O2 (r: 0.52; p < 0.001), and FEV1 and WR (r: 0.62; p < 0.001). There were no significant differences in the occurrence of events and deaths contrasting both groups. The coexistence of HF + COPD induces greater impairment on exercise performance when compared to patients without overlapping diseases, however the overlap of the two diseases did not increase the probability of the occurrence of cardiopulmonary events and deaths when compared to groups with isolated diseases in the period studied. CPET provides important information to guide effective strategies for these patients with the goal of improving exercise performance and functional capacity. Moreover, given our findings related to pulmonary function, body composition and exercise responses, evidenced that the lean mass, FEV1 and DLCO influence important responses to exercise.
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Tolerancia al EjercicioRESUMEN
AIM: Our aim was to assess: 1) the impact of the eccentric left ventricular hypertrophy (ELVH) on exercise performance in patients diagnosed with chronic heart failure (CHF) alone and in patients with co-existing CHF and chronic obstructive pulmonary disease (COPD) and 2) the relationship between left and right cardiac function measurements obtained by doppler echocardiography, clinical characteristics and primary measures of cardiorespiratory fitness. METHODS: The current study included 46 patients (CHF:23 and CHF+COPD:23) that performed advanced pulmonary function tests, echocardiography and symptom-limited, incremental cardiopulmonary exercise testing (CPET) on a cycle ergometer. RESULTS: Patients with CHF+COPD demonstrated a lower work rate, peak oxygen uptake (VO2), oxygen pulse, rate pressure product (RPP), circulatory power (CP) and ventilatory power (VP) compared to those only diagnosed with CHF. In addition, significant correlations were observed between VP and relative wall thickness (r: 0.45 p: 0.03),VE/VCO2 intercept and Mitral E/e' ratio (r: 0.70 p: 0.003) in the CHF group. Significant correlations were found between indexed left ventricle mass and RPP (r: -0.47; p: 0.02) and relative VO2 and right ventricle diameter (r: -0.62; p: 0.001) in the CHF+COPD group. CONCLUSION: Compared to a diagnosis of CHF alone, a combined diagnosis of CHF+COPD induced further impairments in cardiorespiratory fitness. Moreover, echocardiographic measures of cardiac function are related to cardiopulmonary exercise performance and therefore appear to be an important therapeutic target when attempting to improve exercise performance and functional capacity.