Dabigatran + closed head injuries: Higher mortality, no protocols

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Patients treated with dabigatran who had closed head injuries had a higher mortality rate than those on warfarin or on no anticoagulants, according to a review published May 1 in the Journal of Neurosurgery.

Michael W. Parra, MD, of the Delray Medical Center in Delray Beach, Fla., and colleagues retrospectively reviewed the cases of all adult patients with closed head injuries after ground-level falls who were treated at a Level I trauma center between February and May 2011. They divided patients into three groups: those on dabigatran (Pradaxa, Boehringer Ingelheim), warfarin or no anticoagulants.

The FDA approved the use of dabigatran in October 2010 for the prevention of stroke in patients with nonvalvular atrial fibrillation.  Parra et al noted that falls from standing are common in trauma centers, accounting for more than one in four admissions, while 43 percent of all  injuries in patients 65 years and older were due to falls from standing.

“To complicate this matter even further, the prevalence of atrial fibrillation is strongly dependent on age, indicating that the use of oral anticoagulation therapy will probably substantially increase due to the projected aging of the U.S. population,” they wrote.

Their review identified five patients with closed head injuries from ground-level falls who were on dabigatran, 15 on warfarin and 25 on no anticoagulants. The warfarin patients underwent a standardized reversal protocol; there was no protocol for patients on dabigatran.

Demographic and clinical characteristics such as sex, age, race, Injury Severity Score, Glasgow Coma Scale score, comorbidities, associated medications, injury mechanisms or closed head injuries were not significantly different between the dabigatran and warfarin groups. Repeat CT scans during reversals of anticoagulation indicated new or expanded hemorrhage in four of the five dabigatran patients and three of the 15 warfarin patients.

Two of the patients on dabigatran died (40 percent) compared with none of the warfarin patients and none of the patients on no anticoagulants. The institutional mortality rate for closed head injuries after a ground-level fall was 14 percent in 2010.  “The two deaths of the patients on dabigatran were related to the progression of the bleeding/hemorrhage, which cascaded to multiorgan failure and ultimately death,” they explained.

Dabigatran offers several advantages over warfarin, included a predictable anticoagulation response that doesn’t require monitoring, fewer drug-drug interactions and it is not affected by diet. But Parra et al encouraged physicians to weigh in the fact that no agent or protocol currently exists to reverse its effects.

“This demonstrates dabigatran’s devastating potential predicament. On review of our treatment approach, a great deal of variance was observed in regard to the time and type of treatment received,” they observed. “Because of these data, and the literature cited earlier, our institution is establishing a reversal protocol for the treatment of patients on dabigatran presenting with CHI [closed head injury].”

The study was limited by being small and retrospective. In addition, it lacked a standardized method for evaluating hemorrhage blood volume and patients had been treated with other anticoagulants. But their review may be the first to shed light on different outcomes between patients receiving dabigatran and warfarin who experience a closed head injury.

“The intention of this paper is not simply to bring to light the higher mortality rate associated with CHI in patients on dabigatran, but to the fact that physicians are not prepared to deal with it,” they concluded.