Prolonged versus standard-duration venous thromboprophylaxis in major orthopedic surgery: a systematic review.

ABSTRACT

BACKGROUND: The optimal duration of thromboprophylaxis after major orthopedic surgery is unclear. PURPOSE: To compare the benefits and harms of prolonged versus standard-duration thromboprophylaxis after major orthopedic surgery in adults. DATA SOURCES Cochrane Central Register of Controlled Trials and Scopus from 1980 to July 2011 and MEDLINE from 1980 through November 2011, without language restrictions. STUDY SELECTION Randomized trials reporting thromboembolic or bleeding outcomes that compared prolonged (≥21 days) with standard-duration (7 to 10 days) thromboprophylaxis. DATA ABSTRACTION Two independent reviewers abstracted data and rated study quality and strength of evidence. DATA SYNTHESIS: Eight randomized, controlled trials (3 good-quality and 5 fair-quality) met the inclusion criteria. High-strength evidence showed that compared with standard-duration therapy, prolonged prophylaxis resulted in fewer cases of pulmonary embolism (PE) (5 trials; odds ratio [OR], 0.14 [95% CI, 0.04 to 0.47]; absolute risk reduction [ARR], 0.8%), asymptomatic deep venous thrombosis (DVT) (4 trials; relative risk [RR], 0.48 [CI, 0.31 to 0.75]; ARR, 5.8%), symptomatic DVT (4 trials; OR, 0.36 [CI, 0.16 to 0.81]; ARR, 1.5%), and proximal DVT (6 trials; RR, 0.29 [CI, 0.16 to 0.52]; ARR, 7.1%). Moderate-strength evidence showed fewer symptomatic objectively confirmed episodes of venous thromboembolism (4 trials; RR, 0.38 [CI, 0.19 to 0.77]; ARR, 5.7%), nonfatal PE (4 trials; OR, 0.13 [CI, 0.03 to 0.54]; ARR, 0.7%), and DVT (7 trials; RR, 0.37 [CI, 0.21 to 0.64]; ARR, 12.1%) with prolonged prophylaxis. High-strength evidence showed more minor bleeding events with prolonged prophylaxis (OR, 2.44 [CI, 1.41 to 4.20]; absolute risk increase, 6.3%), and insufficient evidence from 1 trial on hip fracture surgery suggested more surgical-site bleeding events (OR, 7.55 [CI, 1.51 to 37.64]) with prolonged prophylaxis. LIMITATIONS: Data relevant to knee replacement or hip fracture surgery were scant and insufficient. Most trials had few events; the strength of evidence ratings that were used may not adequately capture uncertainty in such situations. CONCLUSION: Prolonged prophylaxis decreases the risk for venous thromboembolism, PE, and DVT while increasing the risk for minor bleeding in patients undergoing total hip replacement.