Warfarin anticoagulation after total hip or total knee replacement: Clinical and resource-utilization outcomes in a university-based antithrombosis clinic

• Published in: American journal of health-system pharmacy Vol. 70; no. 5; pp. 423 - 430
• Main Authors: NUTESCU, Edith A, BAUTISTA, Adriana, WEIHUA GAO, GALANTER, William L, SCHUMOCK, Glen T, MODY, Samir H, BOOKHART, Brahim K, LAMBERT, Bruce L
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society of Health-System Pharmacists 01.03.2013; American Society of Health Pharmacists; Oxford University Press
• Subjects: Academic Medical Centers - statistics & numerical data; Academic Medical Centers - trends; Adolescent; Adult; Aged; Ambulatory Care Facilities - statistics & numerical data; Ambulatory Care Facilities - trends; Anticoagulants - therapeutic use; Arthroplasty, Replacement, Hip - trends; Arthroplasty, Replacement, Knee - trends; Biological and medical sciences; Blood clot; Blood. Blood coagulation. Reticuloendothelial system; Cohort Studies; Complications and side effects; Dosage and administration; Drug therapy; Female; Follow-Up Studies; Health Resources - statistics & numerical data; Health Resources - trends; Humans; International Normalized Ratio - trends; Male; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Prevention; Retrospective Studies; Risk factors; Thrombosis; Treatment Outcome; Venous Thromboembolism - epidemiology; Venous Thromboembolism - prevention & control; Warfarin; Warfarin - therapeutic use; Young Adult; United States; Human; Warfarin; Total knee arthroplasty; Prognosis; Coumarine derivatives; Cardiovascular disease; Anticoagulant; Venous disease; Vascular disease; Prevention; Antivitamin K; Hip prosthesis; Orthopedic surgery; Treatment; Venous thrombosis; Thromboembolism
• ISSN: 1079-2082; 1535-2900
• DOI: 10.2146/ajhp120341

Clinical and resource-utilization outcomes associated with warfarin anticoagulation after major orthopedic surgery were evaluated. Consecutive patients who received postsurgical prophylaxis with warfarin within 24 hours of total knee replacement (TKR) or total hip replacement (THR) surgery and who were referred to and had outpatient follow-up for anticoagulation management in a single-center, university-based antithrombosis clinic from January 1, 1998, to January 1, 2009, were included in the study. Data were obtained from existing inpatient and outpatient medical records and retrospectively reviewed. Patient follow-up and data collection were conducted from the time of admission until 90 days after surgery. A total of 400 patients were included in the study; 179 (44.8%) underwent THR and 221 (55.3%) underwent TKR. The mean length of hospital stay was 5.0 ± 1.9 days, and the mean length of warfarin therapy was 50 ± 21 days. The mean time required to reach the target International Normalized Ratio (INR) of 2.0-3.0 was 10.0 ± 9.1 days. The within-patient percentage of INR levels spent in the target range was 28% ± 18%. Objectively confirmed symptomatic venous thromboembolism (VTE) occurred in 16 patients (4%), with 14 events (87.5%) occurring with INR values of ≤2.0 and 2 events (12.5%) occurring with INR values of >2.0. THR and TKR surgical patients at one institution who were receiving postsurgical VTE prophylaxis with warfarin spent a substantial proportion of time with their INR below the target range and had a high rate of symptomatic VTE.