Aspirin Equal to Dalteparin for VTE

A venous thromboembolism is a threat to patients undergoing a total hip arthroplasty (THA). Which is the better preventative—extended use of aspirin or low-molecular-weight heparin? To find out, a bevy of doctors undertook a study of the somewhat controversial role of aspirin in thromboprophylaxis after total hip arthroplasty. They wanted to compare extended treatment with aspirin and dalteparin for prevention of symptomatic venous thromboembolism (VTE) after a THA.

The researchers conducted their randomized controlled trial in 12 orthopedic referral centers in Canada and enrolled 778 patients who had had unilateral THAs between 2007 and 2010. After an initial 10 days of dalteparin prophylaxis the researchers randomly assigned patients to 28 days of either dalteparin or aspirin.

So what happened? Five of 398 patients assigned to dalteparin and one of 380 randomly assigned to aspirin had VTEs. Doctors found that aspirin was non-inferior but not superior to dalteparin.

Clinically significant bleeding occurred in five patients receiving dalteparin and two receiving aspirin. The doctors concluded that extended prophylaxis for 28 days with aspirin was non-inferior to and as safe as dalteparin for the prevention of VTE after THA in patients who initially received dalteparin for 10 days. Given its low cost and greater convenience, they considered aspirin to be a reasonable alternative for extended thromboprophylaxis after THA.

Because of a difficulty with patient recruitment, doctors had to prematurely halt the study which was reported in the Annals of Internal Medicine.