Venous Thromboembolism at High Altitude: Our Approach to Patients at Risk.

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is a prevalent disorder that confers substantial cardiovascular morbidity and, in serious cases, death. VTE has a complex and incompletely understood etiopathogenesis with genetic, acquired, and environmental risk factors. As the focus of this review, one environmental risk factor, which may interact with other risk factors such as hereditary and/or acquired thrombophilias, is travel to high altitude (HA), although current evidence is limited. As guidelines do not directly address this topic, we will discuss the epidemiology of HA-VTE, review the putative mechanisms for thrombosis at HA, and discuss our clinical approach to both risk stratification and counseling, including specific pharmacologic and nonpharmacologic recommendations for patients with elevated VTE risk before they travel to HA.