Most AFib patients need anticoagulation therapy -- but can blood thinners be made safe?

Because atrial fibrillation is strongly associated with strokes, the majority of AFib patients should be taking anticoagulants to thin the blood and prevent clot formation, says Thomas Ortel, MD, PhD, director of Duke's Clinical Coagulation and Platelet Immunology Laboratories and the anticoagulation management service.

Warfarin (often prescribed as Coumadin) is currently the only oral anticoagulant available, and those taking it must minimize their risk of bleeding by monitoring their blood and maintaining a steady amount of vitamin K in their diets.

Even certain medications can disrupt the coagulation balance -- including amiodarone, an antiarrhythmic drug commonly prescribed to AFib patients. Thus, a medical juggling act ensues.

Current practice for using anticoagulants in AFib patients is "all over the place," Ortel says. "There is a general assessment that the higher the risk for thrombosis, the greater the need for anticoagulants," but individual physicians can vary quite a bit in how they manage these drugs.

Newer anticoagulants are now in development to treat venous thrombosis as well as atrial fibrillation, and such drugs may reduce the need for close monitoring. But they aren't available yet and when they are, they could be costly, Ortel says.

For now, clinical staff use handheld monitors to test the patient's international normalized ratios (INR), which provide a measure of the tendency for blood to clot. In Ortel's clinic, the staff enter the values into an Internet-based system called CoagCare that Ortel helped develop and test.

The CoagCare system helps health care providers track patient INR values and offers the opportunity for certain patients to test their own INR and enter the data. He believes this type of tracking, along with more choices for anticoagulants, will ultimately allow for a more personalized approach to medication management.

"I think that in a few years, with more drug development, we're going to be very flexible in how patients on anticoagulants are managed," he says.

Balancing medications to minimize risk of both clots and bleeding events is especially complex in patients who will require surgery.

Ortel is currently enrolling AFib patients in a multi-site study called BRIDGE, which will investigate the use of low-molecular-weight heparin -- a blood thinner that works and wears off more quickly than warfarin -- as a bridge before and after elective procedures.

This article was first published in the Fall 2009 edition of DukeMed Magazine.