Coagulation

Postoperative bridging with LMWH unnecessary in patients with AF: study


Post-procedure bridging with a low molecular weight heparin is not beneficial in patients with AF or mechanical heart valves who require temporary cessation of their warfarin.

A Canadian study, published in The BMJ, comprised 1471 adults in whom warfarin was ceased five days before a procedure and resumed the night of the procedure. All patients received dalteparin at 72, 48 and 24 hours before the procedure.

Patients were randomised to receive dalteparin or placebo at least 12 hours after the procedure and for at least four days and until the INR was greater than 1.9.

“We chose to only study the LMWH dose after the procedure because the dose before the procedure was unlikely to be causing harm and might be of benefit,” the study said.

It found the rate of major thromboembolism within 90 days of the procedure was 1.2% with placebo and 1.0% with dalteparin (P=0.64).

Major bleeding occurred in 2.0% of patients receiving placebo and 1.3% of patients on dalteparin (P=0.32).

The overall results were consistent in both the AF and mechanical heart valves subgroups.

“For the prespecified secondary endpoint of major bleeding or major thromboembolism, 21 (3.2%) events occurred in patients assigned to placebo compared with 19 (2.3%) in patients assigned to dalteparin (P=0.28, −0.9, −2.6 to 0.8). No differences were found for any of the additional secondary outcomes.”

A post-hoc analysis of outcomes at 30 days also found no difference between the postoperative bridging and no bridging groups.

The researchers said their findings were consistent with the BRIDGE trial of perioperative bridging in AF patients.

“Although warfarin is being used less frequently in patients with atrial fibrillation, it is still the long term anticoagulant of choice for patients with mechanical heart valves and in other populations, such as patients receiving dialysis, those with limited supply of direct oral anticoagulants, and in resource constrained settings.”

“Our results are important for such patients. Further studies are needed to determine the need for bridging before procedures in patients with mechanical heart valves.”

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