Right ventricular strain impairment due to hypoxia in patients with COPD

<bold>Background:</bold> Hypoxic pulmonary vasoconstriction leads to an increase in pulmonary artery pressure (PAP) and potentially right heart failure in both healthy individuals and those with respiratory diseases. Previous studies in patients with COPD exposed to hypobaric hypoxia have shown an increase in PAP, while traditional echocardiographic parameters (TAPSE, S’, fractional area change) indicated preserved right ventricular (RV) function, with only minimal changes observed at high altitude. Whether hypoxia has an impact on the RV function of COPD patients using speckle-tracking strain analysis is unclear. <bold>Methods:</bold> This analysis evaluates echocardiographic RV free wall strain (RVFWS) in patients with COPD GOLD 1-3 travelling from 760m to 3100m for a 2-day stay. RVFWS was assessed using the software TomTec. A RVFWS over -20% was deemed abnormal and indicated RV dysfunction. <bold>Results:</bold> A total of 54 patients (57% men, mean±SD age 58 ± 8years, FEV1 %predicted 77.31 ± 22.51) with echocardiographs of sufficient quality were included. The mean RVFWS worsened significantly from -26.7 ± 4.9% at 760m to -23.7±5.8% at high altitude (p=0.017). The number of patients with relevant RV dysfunction based on RVFWS increased from 7.4% at 760m to 27.8% at 3100m (p=0.015), whereas the prevalence of RV dysfunction assessed by traditional indices remained unchanged. <bold>Conclusion:</bold> Exposure to hypoxia caused RV dysfunction in more than one quarter of the patients with COPD. Speckle-tracking strain analysis is a promising, non-invasive technology for evaluating RV function with a suspected higher sensitivity compared to classic echocardiographic indices.