Pulmonary hemodynamics by echocardiography over two days of acclimatization in lowlanders with chronic obstructive pulmonary disease traveling to high altitude.

<bold>Introduction:</bold> Patients with chronic obstructive pulmonary disease (COPD) may experience increased systolic pulmonary artery pressures (sPAP) at high altitude (HA), with an unclear acclimatization. We investigated the effects of acute ascent to 3100m on pulmonary hemodynamics of COPD patients and their acclimatization after a 2-day stay at HA. <bold>Methods:</bold> In this prospective, interventional study, with stable, normocapnic patients with COPD, living at low altitude, with FEV1 40-80%pred., resting SpO2 ≥92%, without altitude related adverse health events (ARAHE) were included. Echocardiography was performed at 760m and directly after arrival at 3100m and the two consequent days. The primary outcome was the change in sPAP at different time points. <bold>Results:</bold> 38 patients (37% females), aged 55±10 years with COPD GOLD 2/3 (FEV1 63±12%pred.) were included. After acute ascent to 3100 vs. 760m, sPAP initially increased by 12 mmHg (9 to 15 mmHg, p<0.001), sPAP/CO increased by 2 WU (1 to 3WU, p=0.001) and TAPSE/sPAP decreased by -0.6 mm/mmHg (−0.9 to -0.2mm/mmHg, p=0.002) whereas the right atrial pressure and cardiac output did not change. At day III, at 3100m, we observed a significant reduction of sPAP by -4mmHg (−7 to -1mmHg, p=0.008) compared to day I. Other echocardiographic parameters did not change. <bold>Conclusion:</bold> In stable COPD patients travelling to 3100m and who did not reveal ARAHE, sPAP initially increased, along with an increased pulmonary resistance and a reduced right ventricular arterial coupling. Spap quickly decreased during 2 days of acclimatization.