The application of supine bicycle exercise stress echocardiograph for identification of susceptibility to acute mountain sickness

Abstract Background Exposure to high altitude is likely to lead to acute mountain sickness (AMS). At present, there are no definite parameters that can accurately predict the occurrence of AMS. Objectives The purposes of this study are (1) to assess the relationship between stress echocardiographic parameters and AMS, (2) to identify the predictors of AMS at sea level by exercise stress echocardiography. Methods A total of 36 healthy adults were enrolled and underwent resting and exercise stress echocardiography on a supine bicycle at sea level. Heart rate (HR) and blood pressure (BP) were monitored during stress echocardiography. Left ventricular (LV) ejection fraction and E/e’ were calculated at rest and peak stage. Other right ventricular systolic function parameters and pulmonary artery pressure (PAP) were calculated at the same time, which included tricuspid regurgitation velocity (TRV), tricuspid annular peak systolic excursion (TAPSE), systolic PAP (sPAP), right ventricular (RV) dimension by 2D, right ventricular area at the end of diastole (RVAD), right ventricular area at the end of systolic (RVAS),RV fraction of area change (FAC), right ventricular outflow tract velocity time integral (RVOT VTI).Pulmonary vascular resistance (PVR) was calculated. All subjects ascended to 3600m within 24 hours by bus. AMS was identified by 2018 Lake Louise Questionnaire Score. Univariable and multivariable logistic regression analysis assessed independent factors associated with AMS. Results At the altitude of 3600m, 13 of 36 subjects had AMS, which defined as AMS (+) group. And the rest was AMS (-) group. There were no significant differences in HR, BP, and LV systolic and diastolic function between the two groups (P > 0.05). TRV, sPAP, and PVR were much higher at peak stage in AMS (+) group (P < 0.05). No significant differences were found in RV systolic function at rest and peak stage between the two groups. By multivariable logistic regression model, PVR and RVAD at peak stage were significantly associated with AMS occurrence (PVR-OR =1.962,95% CI: 0.689-0.973,p =0.002; RVAD-OR =1.962,95% CI: 0.638-0.967,p =0.005;). The cutoff value to predict AMS were 1.55 for PVR (AUC: 0.831) and 11.45 cm2 for RVAD (AUC: 0.802). Conclusions Supine bicycle exercise stress echocardiography is a useful and noninvasive technique to identify subjects susceptible to AMS. Subjects with higher PVR and RVAD at peak stage were associated with susceptibility to AMS.