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A New Way to Prevent Blood Clots After Surgery That Doesn't Involve Blood Thinners

Any one who has had a total hip or total knee replacement knows that a major concern after surgery is the formation of blood clots. Blood clots can break loose and travel to the heart or brain causing heart attacks or strokes. Standard postoperative treatment includes prevention of blood clots. In medical terms, this idea is called thromboembolism prophylaxis.

One of the tools surgeons rely on the most for blood clot prevention is the use of a low-molecular-weight heparin (LMWH) medication. This drug is a blood thinner more commonly known as Warfarin or Coumadin. Another way to prevent blood clot formation is to avoid any bleeding episodes because that's when the blood forms clots to help stop the flow of blood.

Sometimes patients can't be given the prophylactic medication because of the risk of bleeding that comes with using those drugs. Having an alternate treatment approach like compression would be very useful. Right now compression stockings are routinely used after any surgeries involving the lower extremities (legs).

In this study, surgeons compared the use of two different methods used to prevent blood clots: low-molecular-weight heparin (LMWH) and a new compression device. Two groups of patients receiving a total hip replacement were treated with one or the other.

They were followed for 12 weeks to see how many bleeding episodes occurred and how many blood clots developed in each group. They wanted to find out how safe are these devices? And how effective are they? In other words, do they prevent bleeding and/or blood clots? Does this type of compression work better than taking the standard medication? If it did, it would certainly reduce the bleeding risks that come with taking heparin.

The compression device used was applied to the legs right in the operating room before the patients even went to the recovery room. The device used was a portable, battery-operated unit -- small and compact, not like the standard compression devices that are big, bulky, and keep patients from moving around or walking.

The portable compression unit was used by most of the patients in the compression group for 20 of 24 hours over a period of 10 days. It's ease of use made it possible to get patients to continue using it at home as directed. And the unit has a timer that displays when and how long the device is worn. This feature gives the physician information on patient compliance with the program.

The compression group of patients didn't get Warfarin or Coumadin, but they could take one baby aspirin every day after the surgery. About half of the compression group decided to use the aspirin. Aspirin is an anticoagulant meaning it helps keep platelets from sticking together to form a clot. The second group got their first injection of LMWH (Lovenox) within 24 hours of the surgery. Additional doses of Lovenox were given every 12 hours until they left the hospital. At discharge, the heparin group continued to receive a once daily dose for up to 17 total doses.

Everyone was followed closely for any signs or symptoms of bleeding or blood clots. A special ultrasound test of the veins in the leg looking for blood clots was performed 10 to 14 days after surgery. CT scans of the lung were done on anyone suspected of having a pulmonary embolism (PE) or blood clot in the lungs. The results showed no difference between the groups in terms of the number of blood clots that formed in the legs.

The big difference was that the patients in the compression group didn't have even one episode of major bleeding. Six per cent of the heparin group did have significant problems with bleeding -- some even had to receive a blood transfusion. There were some minor bleeding problems in both groups but this was fairly equal: 37 per cent in the compression group and 42 per cent in the heparin group.

In summary, the authors started out the study thinking that this new portable compression device could reduce the number of dangerous bleeding episodes in patients after hip replacement surgery. And they were right! They suggest it may be possible to replace heparin with the compression unit. This idea is based on the fact that there was significantly less major bleeding while at the same time, the same number of blood clots forming. And the unit was easy to use, so patients applied it as directed.

Of course, more studies are needed to confirm the safety and effectiveness of these little take home compression devices. It will be necessary to see if the unit works just as well for all patients or just certain ones. Will some patients do better than others? Does age, body mass index, or general health make a difference? How much time is really needed applying the compression. These are just a few of the questions that must be answered before the use of low-molecular-weight heparin is abandoned for a nonpharmacologic approach to post-operative bleeding and the formation of life-threatening blood clots.

References: Clifford W. Colwell, Jr, MD, et al. Thrombosis Prevention After Total Hip Arthroplasty. In Journal of Bone and Joint Surgery. March 2010. Vol. 92-A. No. 3. Pp. 527-535.

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