Cardiovascular Indicators of Systemic Circulation and Acute Mountain Sickness: An Observational Cohort Study.

Renzheng Chen,Lan Huang,Chunyan He,Yuhan Deng,Jie Yang,Chuan Liu,Mengjia Sun,Jingbin Ke,Xubin Gao,Hu Tan,Fangzhengyuan Yuan,Ran Cheng,Jihang Zhang,Yuanqi Yang

doi:10.3389/fphys.2021.708862

Renzheng Chen, Lan Huang + Show 12 more

Open Access

https://doi.org/10.3389/fphys.2021.708862

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Abstract

Background: Acute high-altitude (HA) exposure results in blood pressure (BP) and cardiac function variations in most subjects, some of whom suffer from acute mountain sickness (AMS). Several previous studies have found that cardiovascular function indicators are potentially correlated with AMS.Objectives: This study aims to examine HA-induced cardiovascular adaptations in AMS patients and compare them with healthy subjects. It also aims to investigate the relationship between cardiovascular function indicators and AMS, as well as to provide some insightful information about the prevention and treatment of AMS.Methods: Seventy-two subjects were enrolled in this cohort study. All the subjects ascended Litang (4,100 m above sea level). They were monitored by a 24-h ambulatory blood pressure (ABP) device and underwent echocardiography examination within 24 h of altitude exposure. The 2018 Lake Louise questionnaire was used to evaluate AMS.Results: Acute mountain sickness group consisted of more women (17 [60.7%] vs. 10 [22.7%], p = 0.001) and fewer smokers (5 [17.9%] vs. 23 [52.3%], p = 0.003). Compared with subjects without AMS, subjects with AMS had lower pulse pressure (PP) (daytime PP, 45.23 ± 7.88 vs. 52.14 ± 4.75, p < 0.001; nighttime PP, 42.81 ± 5.92 vs. 49.39 ± 7.67, p < 0.001) and lower effective arterial elastance (Ea) (1.53 ± 0.24 vs. 1.73 ± 0.39, p = 0.023). Multivariate regression indicated that female sex (OR = 0.23, p = 0.024), lower daytime PP (OR = 0.86, p = 0.004), and lower Ea (OR = 0.03, p = 0.015) at low altitude (LA) were independent risk factors for AMS. Combined daytime PP and Ea at LA had a high predictive value for AMS (AUC = 0.873; 95% CI: 0.789–0.956). Correlation analysis showed that AMS-induced headache correlated with daytime PP (R = −0.401, p < 0.001) and nighttime PP at LA (R = −0.401, p < 0.001).Conclusion: Our study demonstrated that AMS patients had a lower PP and Ea at LA. These baseline indicators of vasodilation at LA were closely associated with AMS, which may explain the higher headache severity in subjects with higher PP at LA.

Highlights

An increasing number of people have access to high-altitude (HA) areas for various reasons
Daytime systolic blood pressure (SBP), nighttime SBP, daytime diastolic blood pressure (DBP), and nighttime DBP increased after acute exposure to HA in all subjects
DBP was similar, daytime and nighttime pulse pressure (PP) were significantly lower in acute mountain sickness (AMS) subjects when compared with non-AMS subjects at low altitude (LA)

Summary

Introduction

An increasing number of people have access to high-altitude (HA) areas for various reasons. Some healthy individuals with poor cardiac acclimation may suffer from acute mountain sickness (AMS), which is characterized, among other symptoms, by dizziness, headache, nausea, insomnia, vomiting, and fatigue (Luks et al, 2017). Previous findings have demonstrated that AMS may be affected by the baseline and HA-induced changes of cardiovascular indices (Lanfranchi et al, 2005; Hamm et al, 2020; Ke et al, 2020). Acute high-altitude (HA) exposure results in blood pressure (BP) and cardiac function variations in most subjects, some of whom suffer from acute mountain sickness (AMS). Several previous studies have found that cardiovascular function indicators are potentially correlated with AMS

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Conclusion