Pulmonary Embolism at Extreme High Altitude: A Study of Seven Cases

Wu, Jialin, Xiaobo Han, Haiwen Ke, Li Wang, Kun Wang, Jianli Zhang, Jun Tang, Wei Yan, Guangjun Wang, and Peng Jiang. Pulmonary embolism at extreme high altitude: A study of seven cases. High Alt Med Biol. XX:000-000, 2022.Background: The incidence of venous thromboembolism (VTE) is high in high-altitude (HA) areas. We analyzed cases of pulmonary embolism (PE) in extreme HA areas to explore the epidemiological characteristics and risk factors of PE in these regions.Methods: Seven cases of PE occurring in an extreme HA region were prospectively collected at an HA (3,800 m) hospital from May to November 2020. All patients resided 5,000 m above sea level and were diagnosed with PE using computed tomography pulmonary angiography.Results: Seven patients (24 +/- 3.6 years old) had symptom onset at a mean altitude of 5,200 +/- 200 m, and the duration spent at HA ranged from 8 to 210 days (99.29 +/- 77.31 days). Cough, expectoration, chest tightness, fever, shortness of breath, and chest pain were the most common symptoms. Six of the seven patients were initially diagnosed with pulmonary inflammation, and four were diagnosed with high-altitude pulmonary edema using computed tomography or X-ray. Most patients presented with an increased concentration of inflammatory cells and high initial D-dimer levels.Conclusions: In this study, a retrospective analysis of PE case data in extreme HA areas suggested that PE was underdiagnosed owing to misdiagnosis or masking by HA-associated disease.