Exercise oscillatory ventilation in patients with coexisting chronic obstructive pulmonary disease and heart failure: Clinical implications

Background: Exercise oscillatory ventilation (EOV) is considered an important variable for predicting poor prognosis in patients with heart failure (HF) with reduced left ventricular ejection fraction (HFrEF). However, there are no studies evaluating EOV presence in the coexistence chronic obstructive pulmonary disease (COPD) and HFrEF. Aims: I) To compare the clinical characteristics of participants with coexisting HFrEF-COPD with and without EOV during cardiopulmonary exercise testing (CPET); and II) to identify the impact of EOV on mortality during follow-up for 35 months. Methods: 50 stable HFrEF-COPD (EF<50%) participants underwent CPET and were followed for 35 months. The parametric Student's t-test, chi-square tests, linear regression model and Kaplan-Meier analysis were applied. Results: We identified 13 (26%) participants with EOV and 37 (74%) without EOV (N-EOV) during exercise. The EOV group had worse cardiac function (LVEF: 30 +/- 6% vs. N-EOV 40 +/- 9%, p = 0.007), worse pulmonary function (FEV1: 1.04 +/- 0.7 L vs. N-EOV 1.88 +/- 0.7 L, p = 0.007), a higher mortality rate [7 (54%) vs. N-EOV 8 (27%), p = 0.02], higher minute ventilation/carbon dioxide production ((V) over dot(E)/(V) over dot CO2) slope (42 +/- 7 vs. N-EOV 36 +/- 8, p = 0.04), reduced peak ventilation (L/min) (26.2 +/- 16.7 vs. N-EOV 40.3 +/- 16.4, p = 0.01) and peak oxygen uptake (mlO(2) kg(-1) min(-1)) (11.0 +/- 4.0 vs. N-EOV 13.5 +/- 3.4 ml.kg(-1).min(-1), p = 0.04) when compared with N-EOV group. We found that EOV group had a higher risk of mortality during follow-up (longrank p = 0.001) than patients with N-EOV group. Conclusion: The presence of EOV is associated with greater severity of coexisting HFrEF and COPD and a reduced prognosis. Assessment of EOV in participants with coexisting HFrEF-COPD, as a biomarker for both clinical status and prognosis may therefore be warranted.