Systemic review finds that potent anticoagulants increase the risk of mortality after THA, TKA

April 2008

Using potent anticoagulants such as low-molecular-weight heparin to prevent pulmonary embolism in total hip or knee arthroplasty patients, as recommended by the Chest Physicians Consensus Statement, may actually increase the risk of all-cause mortality compared to multimodal prophylaxis measures, according to a systematic literature review published in Clinical Orthopaedics and Related Research.

"We believe the American College of Chest Physicians should reconsider their guidelines to reflect the fact that PE (pulmonary embolism) occurs despite the use of potent anticoagulants and may, in fact, expose patients to increased mortality after surgery," the authors said in the study.

Nigel E. Sharrock, BMedSci, MB, ChB, and colleagues at the Hospital for Special Surgery, New York, conducted the systematic review, which included 20 English language studies published during the last 9 years. The researchers focused on studies that involved patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) and divided publications into three categories based on the venous thromboembolism prophylaxis regimen.

Specifically, Group A included the use of low-molecular-weight heparin, ximelagatran, fondaparinux or rivaroxaban, Group B included the use of a multimodal prophylaxis, and Group C included the use of warfarin.

"Multimodal prophylaxis (Group B) was defined as a protocol consisting of intention to use regional anesthesia (epidural or spinal) with or without intraoperative heparin during surgery or pneumatic compression and aspirin after surgery," the study authors noted.

The researchers found that the lowest number of deaths occurred among patients in Group B. Patients in Groups A and C were more than two times as likely to die compared to those in Group B, with no significant difference between Group A and Group C.

Patients in Group A also had a 60% to 70% higher risk of nonfatal PE compared to patients in Group B.

Nonfatal PE occurred in 94 of 15,839 patients in Group A (0.6%) vs. 25 of 7,193 patients in Group B (0.35%), according to the study.

"We show clinical PE occurs despite the use of powerful anticoagulants. The rate of 0.6% is comparable to the rate of 1% previously described with warfarin and low-molecular-weight heparin in cohort studies.

"This literature cannot support the use of powerful anticoagulants to prevent PE, although they clearly reduce the risk of venographically evident deep vein thrombosis," the study authors wrote.

For more information:

Sharrock NE, Gonzalez Della Valle A, Go G, et al. Potent anticoagulants are associated with a higher all-cause mortality rate after hip and knee arthroplasty. Clin Orthop Relat Res. 2008;466:714-721.