Physical exertion at high altitude--another risk factor for coronary stent thrombosis?

We report 2 cases of very late stent thrombosis (VLST) in patients previously treated with drug-eluting stent (DES). In both cases, VLST occurred during intense physical activities at high altitudes. Exposure to high altitudes alters the coagulation cascade, platelet morphology, and function, resulting in a hypercoagulable state. In addition, strenuous exercise provokes a procoagulant state along with increasing the risk of endothelial damage through the effects on coronary blood flow. In light of these cases, we hypothesize that individuals who are involved in intense physical activities at high altitudes may be at increased risk of stent thrombosis. Use of DES in such patients should be carefully considered.