Low Stroke Volume Index in Healthy Young Men Is Associated with the Incidence of Acute Mountain Sickness after an Ascent by Airplane: A Case-Control Study.

Jingbin Ke,Ying Zeng,Shizhu Bian,Lan Huang,Chen Zhang,Jun Jin,Shiyong Yu,Chuan Liu,Jie Yang,Rongsheng Rao,Jihang Zhang,Luca Liberale

doi:10.1155/2020/6028747

Jingbin Ke, Ying Zeng + Show 10 more

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https://doi.org/10.1155/2020/6028747

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Abstract

Background The aims of this study were to explore the characteristics of left ventricular (LV) functional changes in subjects with or without acute mountain sickness (AMS) and their associations with AMS incidence. Methods A total of 589 healthy men were enrolled and took a trip from Chengdu (500 m, above sea level (asl)) to Lhasa (3700 m, asl) by airplane. Basic characteristics, physiological data, and echocardiographic parameters were collected both at Chengdu and Lhasa, respectively. AMS was identified by the Lake Louise Questionnaire Score. Results The oxygen saturation (SpO2), end-systolic volume index, end-diastolic volume index (EDVi), stroke volume index (SVi), E-wave velocity, and E/A ratio were decreased, whereas the heart rate (HR), ejection fraction, cardiac index (CI), and A-wave velocity were increased at the third day after arrival, as evaluated by an oximeter and echocardiography. However, AMS patients showed higher HR and lower EDVi, SVi, CI, E-wave velocity, and E/A ratio than AMS-free subjects. Among them, SVi, which is mainly correlated with the changes of EDVi and altered LV filling pattern, was the most valuable factor associated with AMS incidence following receiver-operator characteristic curves and linear and Poisson regression. Compared with subjects in the highest SVi tertile, subjects in the middle SVi tertile showed higher multivariable Incidence Rate Ratios (IRR) for AMS with higher incidences of mild headache and gastrointestinal symptoms, whereas subjects in the lowest SVi tertile showed even higher multivariable IRR with higher incidences of all the symptoms. Conclusions This relatively large-scale case-control study revealed that the reduction of SVi correlated with the altered LV filling pattern was associated with the incidence and clinical severity of AMS.

Highlights

High-altitude (HA) exposure has been widely recognized as a source of cardiovascular stress
Following acute HA exposure, heart rate (HR), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were increased and SpO2 was decreased in all the groups; Systolic blood pressure (SBP) was elevated in all subjects and acute mountain sickness (AMS)-free subjects but not in AMS patients; the ESVi, end-diastolic volume index (EDVi), and stroke volume index (SVi) were decreased in all subjects and AMS patients but not AMS-free subjects; LV ejection fraction (LVEF) was increased in all the groups, whereas cardiac index (CI) was elevated in all subjects and AMS-free subjects but not in AMS patients; mitral peak E-wave velocity was decreased in all subjects and AMS patients but not in AMS-free subjects, whereas mitral peak A-wave velocity was increased in all the groups, which resulted in a significant reduction of the E/A ratio in all the groups
Linear regression analysis identified that the changes of SVi were mainly associated with the changes of EDVi (R2 = 0:757, p < 0:01) (Figure 4(c)), whereas the reductions of EDVi were significantly associated with the alterations of E/A ratios (R2 = 0:262, p < 0:01) (Figure 4(d)), which was mainly correlated with the changes of E-wave velocity (R2 = 0:522, p < 0:01) (Figure 4(e))

Summary

Introduction

High-altitude (HA) exposure has been widely recognized as a source of cardiovascular stress. It has been well characterized that chronic or long-term HA exposure may lead to severe hypoxemia, hypoxic pulmonary hypertension, right ventricular hypertrophy, and/or right heart failure [1], whereas acute or short-term HA exposure may result in a series of cardiovascular adaptive responses, including increases in the heart rate (HR) both at rest and during exercise, progressive elevations of blood pressures in both healthy individuals and hypertensive patients [2, 3], transient pulmonary vasoconstriction, and incremental changes in cardiac contractility and cardiac output [4].

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