Preventing Blood Clots After Total Hip Replacement

What Factors Affect Blood Clot Formation?

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Each year approximately 200,000 Americans undergo total hip replacement surgery. Statistics reveal that between 400 and 800 people develop a fatal pulmonary embolism in the first three months following this procedure.

A pulmonary embolism results from a condition called deep vein thrombosis, in which a blood clot forms in a deep vein (often in the leg). In some cases, a pulmonary embolism can develop among patients with DVT when part of the clot breaks off and travels through the bloodstream to the lung.

 

Blood Clot Risks and Interventions

A well-publicized research study published in 2000 in the New England Journal of Medicine found that among the California Medicare patients they followed, certain risk factors and interventions affected which patients developed a blood clot hip replacement surgery. It was found that:

  • Overweight patients with a BMI of 25 or more were 2 1/2 times as likely to be hospitalized for blood clots than the control group.
  • Pneumatic compression was of most benefit to patients of average weight. Pneumatic compression (an external device consisting of inflatable cuffs for the purpose of massaging and compressing the legs to prevent blood from pooling in the veins and an increased risk of clot formation) did not reduce the risk of blood clots in overweight patients.
  • Patients of normal weight who used pneumatic compression were 30 percent as likely to be re-hospitalized for blood clots as patients not treated with pneumatic compression.
  • Patients of all weight categories who were treated with anticoagulant drug therapy after going home were only 60 percent as likely to have symptomatic clots as those patients not receiving the therapy.

Certain groups of patients benefit more from certain treatments. The studies point out the importance of pneumatic compression in patients with BMI under 25 and the importance of anticoagulant drug therapy after hospital discharge but future studies are needed to analyze the ineffectiveness of pneumatic compression in patients with BMI over 25.

High-Risk Patients

Certain patients are at higher risk for developing a pulmonary embolism after hip replacement surgery than others. In addition to patients with a high BMI, these include patients who: 

  • Have a previous history of blood clots
  • Ae active tobacco smokers
  • Are currently receiving treatment for cancer

High-risk patients are usually monitored more closely and/or receive blood thinning medications after a hip replacement surgery to prevent clots from forming. 

Preventing Blood Clots After Hip Replacement

In addition to informing you doctor if you have any of the risk factors mentioned above, there are some steps you can take to help protect yourself from a blood clot if planning surgery. These include: 

  1. Quitting smoking (though a smoking cessation program, if necessary), which has been shown to increase the risk of developing a blood clot by to five times. 
  2. Maintain a healthy weight (or lose weight).
  3. Begin moving and as soon as possible after surgery, which moves blood though you system and prevents it from staying in one place long enough to clot.

    Signs and Symptoms of a Blood Clot

    Even when clots do develop, treatment can often be successful when they are identified before complications develop. After surgery, some swelling is normal. However, if you notice sudden or dramatic swelling or tenderness, a limb is too painful to move, and/or you develop a fever, you should alert your doctor. 

    Sources:

    Prevention of Perioperative Deep Venous Thrombosis And Pulmonary Embolism. B. Todd Sitzman, M.D., M.P.H., December, 1998.

    Avoiding Blood Clots After Hip Replacement Surgery, Newswise, 12/14/00.

    Predictors of Rehospitalization for Symptomatic Venous Thromboembolism after Total Hip Arthroplasty, NEJM, 12/14/00, Vol. 343, No.24.

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