Among 56 VTE patients, more than 50% of patients had symptoms of respiratory infection or a history of respiratory infection recently. Among 56 VTE patients, CRP was measured in 44 patients and 35 (79.5%) had increase of CRP, which implies inflammation is related to the occurrence of VTE. In response to the invasion of foreign pathogens to human body, instantaneous innate immune response occurs within 0-4 hours after infection, and early innate immune response occurs 4-96 hours after infection (18, 19) . DVT and PE often occurred after 2-10 days postoperatively, which coincided with the infection process of innate and adaptive immune function (20) .