May 9th, 2013

Bruise Control: Continued Warfarin Beats Heparin Bridging During Device Implantation

Many patients receiving an ICD or a pacemaker are already receiving oral anticoagulants. Current guidelines recommend replacement of the oral anticoagulant with the temporary use of heparin as a bridging strategy. Now a new study, BRUISE CONTROL (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial), offers convincing evidence that this strategy is not beneficial and, in fact, results in an increase in device-pocket hematoma. Results of the trial were presented today at the Heart Rhythm Society meeting in Denver and published simultaneously in the New England Journal of Medicine.

A group of mostly Canadian investigators randomized 681 patients undergoing ICD or pacemaker implantation with an annual risk for thromboembolic events greater than 5% to either heparin bridging or continued warfarin. The trial was terminated early after a prespecified interim analysis by the data and safety monitoring board. The primary outcome — clinically significant device-pocket hematoma, which the investigators defined as a hematoma that led to prolonged hospitalization, interruption of anticoagulation, or hematoma evacuation — was significantly reduced in the continued-warfarin group, as were all three components of the endpoint:

Primary outcome: 3.5% with continued warfarin versus 16% with heparin bridging (RR 0.19, CI 0.10-0.36, p<0.001).

  • Hematoma prolonging hospitalization: 1.2% vs. 4.7% (RR 0.24, CI 0.08-0.72, p<0.006)
  • Hematoma requiring interruption of anticoagulation: 3.2% vs. 14.2% (RR0.20, CI 0.10-0.39, p<0.001)
  • Hematoma requiring evacuation: 0.6% vs. 2.7% (RR 0.21, CI 0.05-1.00, p=0.03)

There were no other statistically significant or clinically significant differences between the groups; continued warfarin therapy did not result in any major perioperative bleeding. The investigators caution that their results only apply to patients like those in the trial who have a high risk for thromboembolic events. In addition, they note, it is unknown whether their results apply to the new generation of oral anticoagulants (dabigatran, rivaroxaban, and apixaban).

“To many, the substantial reduction in pocket hematoma that we observed with continued warfarin may be counterintuitive,” says co-principal investigator Vidal Essebag, in an HRS press release. “One explanation that has been proposed is the concept of an ‘anticoagulant stress test.’ That is, if patients undergo surgery while fully anticoagulated, any excessive bleeding will be detectable and appropriately managed while the wound is still open. In contrast, when surgery is performed with heparin bridging, such bleeding may remain latent, and appear only when full anticoagulation is resumed postoperatively.”

“We hope that Bruise Control will change how we are treating patients around the world,” says lead author David Birnie, in the press release. “Our study conclusively shows that treating patients with a high risk of stroke with continued warfarin instead of heparin bridging will improve patient outcomes, decrease complications and reduce hospitalization.”

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