Evaluation of perioperative fatal pulmonary embolism and death in cancer surgical patients: the MC-4 cancer substudy.
Cancer patients undergoing surgery are at a high risk of venous thromboembolism, but few studies have described the rate of autopsy-confirmed fatal pulmonary embolism after heparin thromboprophylaxis. In a post hoc analysis of a randomized study (MC-4), which compared the efficacy and safety of certoparin (3000 anti-Xa IU, subcutaneously, once-daily) with unfractionated heparin (5000 IU, subcutaneously, three-times daily) in 23078 patients undergoing surgery lasting more than 30 min, the incidence of autopsy-confirmed fatal pulmonary embolism, death and bleeding in the cancer patients (n=6124) was compared with non-cancer patients (n=16954). Fatal pulmonary embolism was significantly more frequent in cancer patients (0.33% [20/6124]) than in non-cancer patients (0.09% [15/16954], relative risk (RR), 3.7 [95% confidence intervals (CI), 1.80, 7.77], p=0.0001) at 14 days post-prophylaxis. Perioperative mortality was also significantly higher in cancer patients than in noncancer patients (3.14% [192/6124] vs. 0.71% [120/16954], RR, 4.54 [95% CI, 3.59, 5.76], p=0.0001), as were blood loss (p<0.0001), and transfusion requirements (p<0.0001). Prevention of venous thromboembolism in cancer surgical patients remains a clinical challenge.