HOUSTON - (Nov. 23, 2011) - Many people at risk of stroke associated with irregular heart rates and other factors take blood thinners. While these drugs can reduce the chance of stroke, they may complicate the treatment of traumatic injuries by worsening bleeding in some instances.
Trauma researchers at the Center for Translational Injury Research (CeTIR) at The University of Texas Health Science Center at Houston (UTHealth) have expressed concerns about a new class of blood thinners. Researchers report that it cannot be rapidly reversed and its effects are difficult to detect in patients with serious injuries. They address these concerns in a correspondence in the Nov. 24 issue of The New England Journal of Medicine.
The first Food and Drug Administration approved drug in this class of blood thinners is dabigatran etexilate. It is designed to lessen the likelihood of stroke in people with atrial fibrillation unrelated to a heart valve problem. Atrial fibrillation is a common type of arrhythmia, a problem with the rhythm of the heartbeat. According to researchers, unlike with other blood thinners, patients on dabigatran do not require frequent testing to determine blood levels and do not have dietary restrictions.
When people on blood thinners are injured, they may bleed quicker and longer than others. Consequently when someone on a blood thinner arrives at an emergency center with a critical injury, one of the highest priorities is the immediate reversal of the anticoagulatory effects of the medication.
While there are multiple ways to reverse the effects of a traditional blood thinner for stroke (warfarin) and a way to measure the amount in the system, the same cannot be said for dabigatran, the researchers report. Patients must wait for the drug to clear their system, which can take approximately 18 hours, or be hooked up to an emergency dialysis machine so the drug can be filtered from their blood. In addition, the researchers are concerned that tests used to detect the drug’s impact are not readily available at many medical centers.
Bryan Cotton, M.D., M.P.H., the lead author of the correspondence and an associate professor of surgery at the UTHealth Medical School, said he is aware of several patients on dabigatran who were injured and who had poor outcomes.
Cotton said he feels helpless when people taking dabigatran show up in an emergency center with injuries suffered in a traffic accident or other traumatic event. “The problem is that I can’t reverse the medication if something happens. I also can’t test the levels of the drug in the patient with readily available lab tests,” Cotton said.
What does this mean for patients taking the medication? “Patients are put on blood thinners for a reason, so none of them should suddenly discontinue the drug. However, they should stop and schedule an appointment with whoever is prescribing this drug (dabigatran) and have an honest and open dialogue regarding the risks of this drug. The risks of dabigatran must be weighed with the benefits of its convenience,” Cotton said.
Trauma is the fourth leading cause of death in the United States and the elderly are the fastest growing population of trauma patients. In fact, trauma is responsible for approximately 40,000 deaths in the United States annually in people older than 65, Cotton said.
Cotton said additional research is needed to develop the tools healthcare teams need to manage the bleeding of injured patients on dabigatran. Cotton’s two coauthors from the UTHealth Medical School are John Holcomb, M.D., and James McCarthy, M.D.
The authors of the correspondence wrote, “As such, we strongly urge that hemorrhagic complications and death resulting from trauma be included as part of the routine surveillance of all newly approved oral anticoagulants.”
When evaluating anticoagulants, greater attention should be paid to the “real-world” impact of these drugs on patients at risk for trauma, Cotton said.
“Patients must be informed about the pros and cons in taking these new medications,” McCarthy said. “The advantages over the traditional warfarin are always discussed with little attention to the potential downside.”
Holcomb is professor, CeTIR director, vice chair of the Department of Surgery and chief of the Division of Acute Care Surgery. McCarthy is an assistant professor of emergency medicine and medical director of the emergency center at Memorial Hermann-Texas Medical Center.
The mission of The Center for Translational Injury Research (CeTIR) is to lead in the research and development of next-generation medical technologies related to hemostasis, resuscitation and computerized decision support for trauma patients.
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