Responses to incremental exercise and the impact of the coexistence of HF and COPD on exercise capacity: a follow-up study

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 V ˙ E / V ˙ CO 2 slope was obtained through linear regression analysis. Additionally, the linear relationship between oxygen uptake and the log transformation of V ˙ E (OUES) was calculated using the following equation: V ˙ O 2 = a log V ˙ E + b, with the constant ‘a’ referring to the rate of increase of V ˙ O 2 . Circulatory power (CP) was obtained through the product of peak V ˙ O 2 and peak systolic blood pressure and Ventilatory Power (VP) was calculated by dividing peak systolic blood pressure by the V ˙ E / V ˙ CO 2 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 %FEV 1 (HF: 84 ± 20, COPD: 54 ± 21, HF + COPD: 65 ± 25). Patients with HF + COPD demonstrated a lower work rate (WR), peak oxygen uptake ( V ˙ O 2 ), 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 V ˙ O 2 (r: 0.56 p