Meds vs. Machine: Postop DVT Prophylaxis Debate

MIAMI BEACH -- Anticoagulant agents effectively prevent deep vein thrombosis (DVT) after total hip replacement or total knee replacement, according to a large body of scientific studies, the internist argued. In contrast to the well- studied, relatively small number of anticoagulants, the myriad of mechanical devices are supported by more limited, less rigorous research in the medical literature, Dr. James D. Douketis said at a meeting on perioperative medicine sponsored by the University of Miami.

The risk of major or clinically relevant bleeding associated with anticoagulant use can be minimized with appropriate administration, said Dr. Douketis, director of the vascular medicine program at St. Joseph?s Healthcare in Hamilton, Ont.

"I agree that the bleeding risk is relatively low if these drugs are used properly, but why do you have to take any risk?" orthopedic surgeon Dr. Clifford W. Colwell Jr. asked at the meeting.

Most bleeding episodes, when they do occur, are easy to mitigate, Dr. Douketis said. Unlike DVTs, most of these events do not have long-term consequences, he said. In addition, mechanical methods are not always benign. There are reports of trauma associated with use of intermittent compression devices, for example.

Dr. Colwell countered that a zero risk of an adverse bleeding event is one of the main benefits of mechanical devices to prevent DVT. For this reason, these devices are ideal for patients at a high risk for bleeding who cannot take anticoagulants, he said. The effectiveness of mechanical compression devices is directly correlated with how much time they are worn and these devices are nearly complication free, said Dr. Colwell, medical director at the Shiley Center for Orthopaedic Research and Education at Scripps Clinic in La Jolla, Calif.

But why can?t these devices be more portable? The ActiveCare+S.F.T. Portable Intermittent Compression Device, or PICD (Medical Compression Systems Ltd.), is a miniature, battery-powered device that overcomes a major limitation of some mechanical device?can be worn out of bed and out of the hospital, Dr. Colwell said.

Dr. Colwell conducted a multicenter, prospective study with his associates that compared effectiveness of the portable device low-molecular-weight heparin for 10 days for total hip arthroplasties and was more compelling (J. Bone Joint Surg. Am. 2010:92:527-35).

At 3 months, the DVT rate was "essentially the same" at 4.1% in the device group compared with 4.2% in the anticoagulant cohort. There was no fatal PE or any deaths among the 410 randomized participants. In addition, major bleeding occurred for 0% of the device wearers and 5.6% of the pharmacologically treated patients.

"I acknowledge that mechanical prophylaxis has a role after major orthopedic surgery, but it?s a second-line strategy," said Dr. Douketis. Pharmacologic prophylaxis should be first-line therapy because it has been shown to prevent DVT, and pulmonary embolism (PE), including fatal PE, he said.

A meta-analysis Dr. Douketis performed with his colleagues showed extended-duration prophylaxis with heparin or warfarin significantly decreased the frequency of symptomatic VTE, compared with placebo after hip or knee replacement (Lancet 2001;358:9-15). There is less confidence about prevention of proximal DVTs with mechanical devices. The risks should be weighed against this efficacy, Dr. Douketis said.

Dr. Douketis disclosed that he is a consultant for AGEN, Ortho-Janssen, Boehringer Ingelheim, Pfizer, and Bristol-Myers Squibb. Dr. Colwell disclosed he is a consultant and receives research grants from Medical Compression Systems Inc.