Document Detail

Does international normalized ratio level predict pulmonary embolism?
MedLine Citation:
PMID:  21879412     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Preventing pulmonary embolism is a priority after major musculoskeletal surgery. The literature contains discrepant data regarding the influence of anticoagulation on the incidence of pulmonary embolism after joint arthroplasty. The American College of Chest Physicians guidelines recommend administration of oral anticoagulants (warfarin), aiming for an international normalized ratio (INR) level between 2 and 3. However, recent studies show aggressive anticoagulation (INR > 2) can lead to hematoma formation and increased risk of subsequent infection.
QUESTIONS/PURPOSES: We asked whether an INR greater than 2 protects against pulmonary embolism.
PATIENTS AND METHODS: We identified 9112 patients with 10,122 admissions for joint arthroplasty between 2004 and 2008. All patients received warfarin for prophylaxis, aiming for an INR level of 2 or lower. We assessed 609 of 10,122 admissions (6%) for pulmonary embolism using CT, ventilation/perfusion scan, or pulmonary angiography, and 163 of 10,122 admissions (1.6%) had a proven pulmonary embolism.
RESULTS: Fifteen of 163 admissions (9%) had an INR greater than 2 before or on the day of workup compared to 35 of 446 admissions (8%) who were negative. We observed no difference between the INR values in patients with or without pulmonary embolism.
CONCLUSIONS: We found no clinically relevant difference in the INR values of patients who did or did not develop pulmonary embolism. The risk of bleeding should be weighed against the risk of pulmonary embolism when determining an appropriate target INR for each patient, as an INR less than 2 may reduce the risk of bleeding while still protecting against pulmonary embolism.
LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions to Authors for a complete description of levels of evidence.
Patricia Hansen; Benjamin Zmistowski; Camilo Restrepo; Javad Parvizi; Richard H Rothman
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical orthopaedics and related research     Volume:  470     ISSN:  1528-1132     ISO Abbreviation:  Clin. Orthop. Relat. Res.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-01-11     Completed Date:  2012-02-27     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  0075674     Medline TA:  Clin Orthop Relat Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  547-54     Citation Subset:  AIM; IM    
The Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107, USA.
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MeSH Terms
Administration, Oral
Aged, 80 and over
Anticoagulants / administration & dosage*,  adverse effects
Arthroplasty, Replacement / adverse effects*
Blood Coagulation / drug effects*
Chi-Square Distribution
Hemorrhage / chemically induced
International Normalized Ratio*
Middle Aged
Patient Selection
Perfusion Imaging
Predictive Value of Tests
Pulmonary Embolism / blood,  diagnosis,  etiology,  prevention & control*
Retrospective Studies
Risk Assessment
Risk Factors
Time Factors
Tomography, X-Ray Computed
Young Adult
Reg. No./Substance:

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