Table 3.

Comparison of pulmonary embolism characteristics between high-altitude and low-altitude regions.

	High-altitude pulmonary embolism	Low-altitude pulmonary embolism
Epidemiology	Pulmonary embolism appears more frequent at high altitude, but specific epidemiological data are lacking.	The annual incidence of pulmonary embolism ranges from 39 to 115 cases per 100,000 population [31, 32]
Pathophysiology	Hypoxia-induced polycythemia, hyperviscosity, slow venous return, endothelial dysfunction	Typically caused by thrombus dislodgement from deep veins
Clinical features	Severe dyspnea, marked hypoxemia, sometimes RV failure or overlap with HAPE	Typical PE symptoms: Chest pain, dyspnea, hemoptysis
Lab results	D-dimer↑, Hb↑, Hct↑, significant hypoxemia (↓PaO2)	D-dimer↑, mild, or no hypoxemia
Imaging findings	Central or multifocal PE on CTPA, frequent pulmonary hypertension; RV strain on echocardiography	Peripheral PE more common, PAP normal, or slightly elevated
Treatment considerations	Anticoagulation, oxygen therapy, and altitude descent, Thrombolysis when necessary	Anticoagulation, oxygen therapy, and thrombolysis when necessary