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Prophylactic use of LMWH plus intermittent pneumatic compression prevented DVT in hip or knee arthroplasty
  1. John W Eikelboom, MD
  1. McMaster University Hamilton, Ontario, Canada

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 Q In patients receiving primary unilateral total hip or total knee replacement surgery, is prophylactic use of low molecular weight heparin (LMWH) plus intermittent pneumatic compression more effective than LMWH plus graduated compression stockings for reducing deep venous thrombosis (DVT)?

    Clinical impact ratings IM/Ambulatory care ★★★★★★☆ Internal medicine ★★★★★★☆ Surgery ★★★★★☆☆ Haematology ★★★★☆☆☆

    METHODS

    Embedded ImageDesign:

    randomised controlled trial.

    Embedded ImageAllocation:

    {concealed*}.

    Embedded ImageBlinding:

    unblinded.*

    Embedded ImageFollow up period:

    6–12 weeks

    Embedded ImageSetting:

    a university hospital in Germany

    Embedded ImagePatients:

    139 patients ⩾18 years of age who were awaiting primary unilateral total hip or knee replacement. Exclusion criteria included a history of cardiac insufficiency and chronic renal insufficiency.

    Embedded ImageIntervention:

    thromboembolic prophylaxis with LMWH plus intermittent pneumatic compression (n = 70) or LMWH plus graduated compression stockings (class 1, 20–30 mm Hg) (n = 69) after surgery. LMWH prophylaxis comprised anti-Xa enoxaparin-natrium, 4000 IU per day. Intermittent pneumatic compression using a VenaFlow System with 2 cell calf cuffs commenced directly after surgery in the recovery room and continued for 10 days. After intermittent pneumatic compression, patients were fitted with graduated compression stockings on both legs. Patients without thromboembolic complications continued LMWH prophylaxis for 30 days and wore graduated compression stockings for ⩽3 months.

    Embedded ImageOutcomes:

    DVT at day 6–12 (diagnosed by compression ultrasonography).

    Embedded ImagePatient follow up:

    94% (mean age 64 y, 64% men).

    MAIN RESULTS

    The table shows the results. {5 of the 18 patients with DVT were symptomatic.}*

    Prophylactic use of low molecular weight heparin (LMWH) plus intermittent pneumatic compression (IPC) v LMWH plus graduated compression stockings (GCS) in unilateral hip or knee arthroplasty*

    CONCLUSION

    In patients who have total hip or total knee replacement, prophylactic use of low molecular weight heparin (LMWH) plus intermittent pneumatic compression was more effective than LMWH plus graduated compression stockings for preventing deep venous thrombosis.

    Commentary

    Combining mechanical with pharmacological methods of thromboprophylaxis in patients who have total hip or knee replacement is attractive because these patients have a 1–3% incidence of in-hospital symptomatic DVT and a 15–30% prevalence of asymptomatic DVT at hospital discharge despite routine LMWH or warfarin.1 Few studies have evaluated the effectiveness of combined thromboprophylaxis or compared the effectiveness of different mechanical methods in major orthopaedic surgery.2,3

    The study by Silbersack et al showed a 100% (95% CI 81% to 100%) relative risk reduction of DVT in high risk patients who received LMWH plus intermittent pneumatic compression compared with those who received LMWH plus graduated compression stockings. DVT did not occur in any of the 70 patients randomised to intermittent pneumatic compression despite premature discontinuation of treatment in almost 26% of patients (18/70) in this group. These promising results suggest a wider role for combined intermittent pneumatic compression and LMWH in patients who have total hip or knee replacement.

    However, important issues remain unresolved. Firstly, all but 2 of the 18 outcome events in this trial were distal thrombi. Prevention of these events is of limited clinical relevance because most resolve spontaneously and only about one sixth extend to involve the proximal veins.4 Secondly, a significant reduction in proximal or symptomatic thrombi (which are clinically most important) was not shown; the study was not powered for these outcomes. Thirdly, outside of a clinical trial setting, compliance with IPC is likely to be even lower than observed in this study. This drawback may reduce the effectiveness of IPC in routine clinical practice. Future studies should address these issues.

    References

    View Abstract

    Footnotes

    • * See glossary.

    • Information provided by author.

    • * Information provided by author.

    • For correspondence: Dr Y Silbersack, Martin Luther University, Halle/Salle, Germany

    • Source of funding: Aircast Europa GmbH.

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