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Wednesday, March 15, 2000

Successful strategy to control emboli after THR, TKR

Prevention of fatal pulmonary emboli is an important goal after total joint arthroplasty. Because fatal pulmonary emboli are rare, strategies for prophylaxis must have low complication rates associated with their use (e.g., hematoma).

Researchers in poster exhibit 76 describe a successful strategy of outpatient warfarin DVT prophylaxis after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The strategy was four weeks of adjusted dose warfarin with a target INR=1.6-2.0.

They evaluated all patients undergoing THA and TKA, performed by a single surgeon, from 1996-1998. The study group consisted of 377 patients undergoing 457 arthroplasties. PT/INR labs were obtained on a weekly basis after hospital discharge, with adjustment of dosage as indicated. DVT screening was not performed and warfarin was empirically discontinued at four weeks postoperatively.

The efficacy of the treatment protocol was described as excellent. There were no fatal pulmonary emboli, one symptomatic pulmonary embolism (0.27 percent), and one symptomatic DVT (0.27 percent).

"Patients were specifically evaluated for hematomas and bleeds associated with the arthroplasty, other bleeds (e.g. gastrointestinal, cerebral), and dosage and administration errors associated with warfarin. There were two clinically apparent bleeds and/or hematomas (0.53 percent) associated with the arthroplasties. One of these resulted from a pharmacy transcription error (filled as 5mg Q.I.D. rather than 5mg Q.D.). No patient required additional surgery for these problems. There were no clinically apparent gastrointestinal, cerebral or other bleeds. There were four known cases (1.1 percent) in which the patient took the incorrect dosage of warfarin (two pharmacy transcription errors and two patient errors). One of these directly led to a bleed associated with a THA. No problems were identified with the other errors, although these potentially could have led to complications.

From this study, it may be concluded that four weeks of adjusted dose warfarin is a safe and effective strategy for thromboembolic prophylaxis after total hip or knee arthroplasty.

The researchers, all of Orthopaedics Indianapolis, Indianapolis, Ind., are Jeffery Pierson, MD, clinical instructor, Indiana University School of Medicine; Jana L. Schmidt, RN, BSN, research nurse, Orthopaedic Research Foundation of Indiana; and Vanessa M. Miller, RN, BSN, clinical nurse, Orthopaedics Indianapolis.

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2000 Academy News March 15 Index B

Last modified 06/March/2000 by IS