Pulmonary haemodynamics by echocardiography over 3 days of acclimatization in lowlanders with chronic obstructive pulmonary disease travelling to 3100 m of high altitude.

Abstract

Aims: Patients with chronic obstructive pulmonary disease experience an increase in systolic pulmonary artery pressure (sPAP) when exposed to high altitude with an unclear acclimatization. We investigated the effects of acute ascent to 3100 m on pulmonary haemodynamics of patients with chronic obstructive pulmonary disease and their acclimatization during a 3-day stay at high altitude.

Methods and results: In this prospective, interventional study, stable, normocapnic patients with chronic obstructive pulmonary disease, with FEV₁ 40-80%predicted and SpO₂ ≥ 92%, residing at low altitude and staying for 3 days/nights at 3100 m without adverse events, were included. Echocardiography was performed at 760 m, directly after arrival at 3100 m (HA1) and the two following days (HA2/HA3). The primary outcome was the change in sPAP at different time points. Additionally, cardiac output (CO), tricuspid annular plane systolic excursion (TAPSE), and other echocardiographic parameters were measured. Thirty-eight patients with chronic obstructive pulmonary disease (37% females), aged (mean ± SD) 55 ± 10years, with FEV₁ 63 ± 12%predicted, were included. After acute ascent to 3100 m vs. 760 m, sPAP increased by 12 mmHg [95% confidence interval (CI): 9-15, P < 0.001], total pulmonary resistance (sPAP/CO) increased by 2 WU (1-3, P = 0.001), and TAPSE/sPAP decreased by -0.6 mm/mmHg (-0.9 to -0.2, P = 0.002). Right atrial pressure and CO were unchanged. At HA3 compared to HA1, sPAP decreased by -4 mmHg (-7 to -1, P = 0.008); no significant changes in further echocardiographic parameters were observed.

Conclusion: In stable patients with chronic obstructive pulmonary disease travelling to and staying at 3100 m for 3 days/nights without adverse events, sPAP initially increased, along with an increased pulmonary resistance and a reduced right ventricular-arterial coupling reflected by a lower TAPSE/sPAP. Whereas sPAP steadily decreased during acclimatization, other echocardiographic parameters remained unchanged.