Thromboprophylaxis in colorectal surgery: A systematic review

The purpose of this study was to describe the effectiveness of prophylactic measures used to decrease the incidence of thromboembolism after colorectal surgery. The analysis has focused on heparins, mechanical methods, and combinations of the two. MEDLINE, EMBASE, abstract books, and reference lists from previously performed reviews were searched for randomized controlled trials (RCTs) or case control trials (CCTs) comparing prophylactic interventions and/or placebo. Five hundred fifty-eight studies on prophylaxis were identified. Of these, 18 studies met the inclusion criteria. Data extraction was done by at least 2 of the authors. Outcome was deep venous thrombosis and/or pulmonary embolism diagnosed by various methods. Results show that any kind of heparin is better than no treatment or placebo (10 studies), with a Peto odds ratio (POR) of 0.34 (95% Cl 0.20-0.57). Unfractionated heparin and low molecular weight heparin (LMWH) (4 studies) were equally effective, with a POR of 1.01 (95% Cl 0.67-1.52). The combination of graduated compression stockings and LMWH is better than LMWH alone (2 studies), with a POR of 4.17 (95% Cl 1.37-12.70). The optimal method for preventing thromboembolism in colorectal surgery is the combination of graduated compression stockings with either low-dose unfractionated heparin or low molecular weight heparin.