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    Evaluating VTE Risk in Revision THA Patients

    A study presented at the AAOS Annual Meeting shows that healthy revision total hip arthroplasty patients have about the same chance of developing a deep vein thrombosis or pulmonary embolism as healthy patients undergoing primary hip replacement.

    When considering the risk of venous thromboembolic events (VTE) among total hip arthroplasty (THA) patients, it seems reasonable to be more concerned about revision THA patients than primary THA patients.

    But according to research presented at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons in New Orleans, healthy revision THA patients are at no more risk for VTE overall than healthy primary THA patients.

    The researchers, from Rush University Medical Center and Drexel University College of Medicine, retrospectively analyzed data on all primary and revision THAs included in the American College of Surgeons National Surgical Quality Improvement Program database for the period 2011 through 2014. They compared the following data points for 74,405 THA cases (66,839 primary, 7,566 revision):

    • Demographics
    • Medical co-morbidities
    • VTE rates within 30 days of surgery (deep vein thrombosis [DVT] and pulmonary embolism [PE])

    Revision THA patients had a higher rate of DVT, but not PE, than the primary THA patients (0.6% vs. 0.4% for DVT, P=0.016; 0.3% vs. 0.2% for PE, P=0.116). But, revision THA itself was not found to be a risk factor for DVT (odds ratio [OR] 0.833, 95% confidence interval [CI] 0.564-1.232) or PE (OR 1.009, 95% CI 0.630-1.616) when the researchers controlled for confounders.

    They identified 7 independent risk factors for DVT, all P<0.05:

    • Age over 70 years
    • Malnutrition
    • Infection
    • Operating time exceeding 3 hours
    • Use of general anesthesia
    • ASA classification 4 or more
    • Kidney disease

    Three independent risk factors for PE were identified, all P<0.05:

    • Age over 70 years
    • African American ethnicity
    • Operating time exceeding 3 hours

    “Our data show that revision surgery, in and of itself, is not associated with an increased risk of venous thromboembolic events,” said P. Maxwell Courtney, MD, first author of the study. Healthy patients without the independent risk factors mentioned above “may be treated with just a low-level anticoagulant such as aspirin.”

    But patients with the independent risk factors may need more-aggressive anticoagulation – such as with a Factor Xa inhibitor, enoxaparin, or warfarin – than they would get with aspirin.

    Of course, aggressive therapy has its own drawbacks. “We have to weigh the risks and benefits of anticoagulating patients to prevent VTE versus bleeding problems postoperatively,” Dr. Courtney said. “One of the worst things that can happen in a patient who’s being aggressively anticoagulated is that their wound keeps draining, which makes them prone to infection, additional surgery, and additional morbidity.”

    The take-home message for surgeons, Dr. Courtney said, is that “aspirin is still a reasonable chemoprophylactic agent against VTE, even in revision arthroplasty, in the absence of other risk factors.”

    And he practices what he preaches, based on the study results. “My revision patients now get a baby aspirin twice a day unless they have some other risk factors,” he said.

    Source

    Courtney PM, Boniello AJ, Levine BR, Paprosky WG, Sheth NP. Revision Surgery Alone Does Not Increase Rates of Deep Vein Thromboses and Pulmonary Emboli: An Analysis of Risk Factors for Venous Thromboembolic Events after Total Hip Arthroplasty. (Paper 538). Presented at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 6-10, 2018, New Orleans, Louisiana.

    Disclosures

    The study authors have no disclosures relevant to this article.