Abstract
After decades of clinical experience and hundreds of studies, the ideal method of deep vein thrombosis (DVT) prophylaxis remains controversial. One of the most widely quoted publications on the subject in recent years has been the guidelines published by the American College of Chest Physicians (ACCP). The seventh and eighth ACCP Conference on Antithrombotic Therapy and Prevention of Thrombosis were published in Chest in 2004 and 2008 respectively. The highest level recommendation (1-A) was reserved for Warfarin at a relatively high dose (target international normalised ratio (INR) of 2–3), Low Molecular Weight Heparin (LMWH), or Fondaparinux for a minimum of 10 days for both total hip and total knee replacement. These agents were recommended for all patients, regardless of their relative risk of bleeding or risk of venous thromboembolism (VTE). These recommendations were found to be aggressive by the standards of most orthopaedic surgeons and a number of issues were identified with the methodology and resulting recommendations of the ACCP including: The emphasis on multicentre randomised clinical trials that are enormously expensive and strongly weighted towards pharmaceutical sponsored studies, methodology that prevented inclusion of studies of lower cost, lower tech options such as aspirin or lower dose Warfarin since randomised trials on a large scale are not available due to lack of funding or pharmaceutical company interest in generic low-cost options, lack of consideration of pneumatic compression options such as newly available mobile foot pumps with chips for monitoring compliance, financial conflict of interest of virtually all of the authors of the guidelines and the fundamental problem with utilising asymptomatic DVT as a study endpoint. The concerns with the aggressive nature of these recommendations were confirmed by studies from two academic centres which reported a high incidence of wound and bleeding complications when changing to a 1-A protocol. Recent studies indicate that readmissions following joint replacement are much more likely to be due to wound drainage and bleeding complications than DVT or pulmonary embolism (PE). In response to these concerns, the AAOS released guidelines in 2008 that were updated in 2011. The resulting recommendations represented a dramatic departure from the ACCP guidelines. Clinically crucial endpoints such as PE and death were utilized in the analysis rather than asymptomatic DVT, which was the criteria utilised by the Chest Physicians and the 2011 recommendations also considered symptomatic DVT. The AAOS guidelines consider patient risk category rather than making a uniform recommendation for all patients. Much more discretion is given to surgeons to utilise less aggressive prophylactic strategies including aspirin and foot pumps.
In 2012, the ninth edition of the ACCP guidelines was published and many of the concerns previously expressed over prior editions were successfully addressed. Conflict of interest among the authors was much less of an issue, there was more attention placed on symptomatic events and clinically important complications, and a wider scope of literature was considered. The resulting guidelines represented a dramatic departure from previous recommendations. Aspirin and pneumatic compression were elevated to level 1 recommendation status along with potent drug regimens such as injectable drugs (LMWH and Xa inhibitor) as well as the new oral Xa inhibitors and antithrombin agents. When pneumatic compression devices are utilised, the use of a battery powered device capable of recording compliance was recommended. Patient risk status as well as patient preference were also considered. The new ACCP guidelines have successfully addressed many of the concerns previously addressed and are much more in line with the AAOS guidelines. It is anticipated that the federal Surgical Care Improvement Project (SCIP) guidelines for VTE prophylaxis will be released in 2013 and will also embrace the changes recommended by the ACCP. It is further likely that the AAOS and ACCP guidelines are close enough that they may well join forces in the near future and release a single unified document.
