Should we follow the 9th ACCP guidelines for VTE prevention in surgical patients?

The 9th edition of the American College of Chest Physicians (ACCP) guidelines on antithrombotic therapy and prevention, includes relevant changes compared to previous versions. In the 9th ACCP, leadership of most chapters was given to methodologists who were familiar with the GRADE methodology. All topic panelists underwent a selection process paying particular attention to their financial and intellectual conflicts of interests. In the 9th ACCP guidelines, evidence has been explicitly presented in many evidence profiles and summary of evidence tables. In order to get a more balanced trade-off between desirable and undesirable effects of the alternative prevention and therapeutic interventions, there has been an increased emphasis on clinically relevant events, as opposed to previous surrogate asymptomatic outcomes. In addition, there has been a systematic review and survey on patient values and preferences for thrombotic and bleeding outcomes. As a result of the above changes, the strength of most recommendations has been downgraded compared to previous editions. The main changes regarding prevention on nonorthopedic surgical patients include the adoption of two risk assessment models. The only recommendation that has been upgraded is to extend prophylaxis with low molecular weight heparins (LMWH) for four weeks after abdominal or pelvic cancer surgery. A controversial modification in orthopedic patients is recommendation in favor of the use of aspirin after hip or knee arthroplasty. New oral anticoagulants are recommended, but LMWH are suggested as the preferred option. Extending pharmacological prophylaxis for up to 35days rather than 10-14days is now suggested for patients undergoing major orthopedic surgery.