AHA 2008: Anticoagulation can be maintained during invasive procedures

A patient on chronic warfarin is scheduled for a pacemaker implantation, so naturally you discontinue the warfarin several days prior to the procedure to reduce the chance of bleeding. That may not be necessary, says Peter H. Belott, MD, who contends that “we can keep the patient [at a] therapeutic INR [international normalized ratio] and will not incur any deleterious effects.”

The American College of Chest Physicians (ACCP) recommends interrupting vitamin K antagonists (ie, warfarin) prior to device implantation and bridging with therapeutic dose low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) in patients at high or moderate risk of thromboembolism. For patients at low risk, ACCP recommends low-dose heparin and no bridging. For patients on antiplatelet drugs, ACCP suggests continuing them if the patients have a bare metal or drug-eluting stent.

Dr. Belott’s own review of anticoagulation practices during antiarrhythmic device procedures, however, suggests that maintaining the INR at the time of surgery is safe. “The fears of uncontrollable hemorrhage associated with warfarin in surgery are unfounded,” he says.

Over 12 years and 9 months, he collected data related to patient demographics, procedures performed, preoperative INR, and bleeding complications on 2,392 procedures, 431 of which were performed while the patient was maintained on warfarin (average INR: 2.2). During this period, there were 22 bleeding complications.

During the most recent 18 months, 74 of 320 procedures were performed while maintaining warfarin (average INR: 2.2). Most of the INRs in the patients maintained on warfarin were “well within the therapeutic range.” Only one bleeding complication occurred and it happened in a patient who was not on warfarin, notes Dr. Belott, a cardiologist in El Cajon, Calif.

The overall complication rate of 0.91 percent was “extremely small,” he says. The complication rates were 1.62 percent in the anticoagulated patients and 0.76 percent in the nonanticoagulated patients.

In other reviews of anticoagulation in patients undergoing implantation of antiarrhythmic devices, bridging was associated with an increased risk of bleeding complications, increased hospital cost, and increased length of stay, whereas maintaining warfarin with a therapeutic INR did not increase bleeding risk. The practice of maintaining warfarin in patients undergoing heart transplant was also shown to be safe.

Normalizing blood clotting requires as long as 7 days in patients on chronic aspirin therapy after interruption and more than 5 days in those on clopidogrel. In patients on dual antiplatelet therapy, holding antiplatelet therapy before device implantation is warranted; for patients on single drug therapy, the jury is still out, he says.