For years we have been looking for alternatives to anticoagulants to prevent venous thrombembolism in patients undergoing total joint replacements. As many as 50% of patients undergoing total hip arthroplasty may develop deep venous thrombosis (DVT) if no prophylaxis is given. While we often use mechanical prophylaxis (pneumatic compression devices) to supplement anticoagulants, the standard of care still recommends use of anticoagulant prophylaxis in those patients with no contraindications. Yet risk of bleeding complications remains a major fear in such cases.
A new paper (Colwell 2010) reports on a randomized prospective trial of a new mobile compression device in approximately 400 patients undergoing total hip arthroplasty. Patients were randomized to either low-molecular weight heparin (beginning the day after surgery) or the mobile compression device (beginning intraoperatively). Aspirin 81 mg. daily was allowed in the latter group. Major bleeding events occurred in none of the patients in the mobile compression device group and in 6% of the low-molecular weight heparin group. No statistically significant differences were seen for DVT or pulmonary embolism between the two groups.
Note, however, that this study was industry-funded and was not blinded to patients, physicians or investigators. More importantly, this study was not powered to compare the efficacy of this mobile compression device vs. anticoagulant prophylaxis. The authors estmate that a study comparing efficacy of this device vs. anticoagulant prophylaxis would require about 1500 patients per group.
So consider this a pilot study and look for a larger study to be done before you rush out and try to order these new devices. Having a means of reliably preventing DVT without the risk of bleeding complications is clearly in the best interests of patient care. But we need to be sure that the net benefit outweighs that we currently see with pharmacological prophylaxis.
Colwell CW, Froimson MI, Mont MA, et al. Thrombosis Prevention After Total Hip Arthroplasty. A Prospective, Randomized Trial Comparing a Mobile Compression Device with Low-Molecular Weight Heparin. J Bone Joint Surg Am 2010; 92: 527-535