Subcutaneous heparin versus low-molecular-weight heparin as thromboprophylaxis in patients undergoing colorectal surgery - Results of the Canadian DVT prophylaxis trial: A randomized, double-blind trial

Objective To compare the effectiveness and safety of tow-dose unfractionate d heparin and a tow-molecular-weight heparin as prophylaxis against venous thromboembolism after colorectal surgery. Methods In a multicenter, double-blind trial, patients undergoing resection of part or all of the colon or rectum were randomized to receive, by subcu taneous injection, either calcium heparin 5,000 units every 8 hours or enox aparin 40 mg once daily (plus two additional saline injections). Deep vein thrombosis was assessed by routine bilateral contrast venography performed between postoperative day 5 and 9, or earlier if clinically suspected. Results Nine hundred thirty-six randomized patients completed the protocol and had an adequate outcome assessment. The venous thromboembolism rates we re the same in both groups. There were no deaths from pulmonary embolism or bleeding complications. Although the proportion of all breeding events in the enoxaparin group was significantly greater than in the low-dose heparin group, the rates of major bleeding and reoperation for bleeding were not s ignificantly different. Conclusions Both heparin 5,000 units subcutaneously every 8 hours and enoxa parin 40 mg subcutaneously once daily provide highly effective and safe pro phylaxis for patients undergoing colorectal surgery. However, given the cur rent differences in cost, prophylaxis with low-dose heparin remains the pre ferred method at present.