Effect of eccentric cycling on oxygen uptake and hemodynamics in patients with pulmonary vascular disease.

<bold>Introduction:</bold> Eccentric cycling exercise (ECC) allows training at low metabolic costs and may therefore be valuable for patients with pulmonary hypertension (PH) due to pulmonary vascular disease (PVD). The aim of this study was to compare ventilatory and circulatory outcomes of ECC vs. conventional cycling (CON) in patients with PVD. <bold>Methods:</bold> This was a randomized controlled crossover trial in which patients diagnosed with PVD defined as either pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) performed a CON- and ECC cycling test, at identical work-rates, according to stepwise incremental protocols. The main outcome oxygen uptake (V’O2) and additional cardiorespiratory outcomes were measured breath-by-breath by ergospirometry. Hemodynamic parameters like systolic pulmonary artery pressure (sPAP) and TAPSE were measured by echocardiography. <bold>Results:</bold> 33 patients (19 PAH, 14 CTEPH, 13 females, 50±15 years) were included. At identical work-rates during ECC compared to CON, V’O2 was significantly lower by -200ml/min (−40%, -272 to -129, p<0.001), minute ventilation by -5.5 l/min (−30%,95CI: -9.2 to -3.1, p=0.008), and sPAP by -12 mmHg (−20%,95CI: -20 to -4 p=0.006). Right ventricular–arterial coupling as TAPSE/sPAP was 0.11 mm/mmHg (+31%,95CI: 0.04 to 0.18, p=0.007) higher. No adverse events occurred. <bold>Conclusion:</bold> The current study supports the hypothesis that ECC is a feasible and well-tolerated exercise modality for PVD patients with relevantly lower O2 demand and a reduced load on the right ventricle. Future studies should investigate whether ECC improves exercise capacity, muscle force and possibly hemodynamics during prolonged rehabilitation programs in patients with PVD.