Venous thromboembolism (VTE) consists of deep vein thrombosis (DVT), pulmonary embolism (PE), or both. In these chapters on VTE, the word risk factors refer to those epidemiologic and genetic variables that expose someone to a higher risk of developing venous thrombosis. The word triggers refer to those factors in the patient’s immediate history or environment that may have lead to the occurrence of the venous thrombosis. The triggers of VTE include injury to a deep vein from surgery, a fracture, or other trauma, especially a paralytic spinal cord injury.^[1] Another trigger for VTE is prolonged immobilization that causes stasis in the deep veins which may occur after surgery, prolonged bed-rest, or prolonged seating during travel.

Shown below is a list of triggers of VTE.^[1][2] The triggers are classified as strong, moderate, or weak depending on how strongly they predispose for a VTE.