Periprocedural management of oral anticoagulation: When and how to hit “pause”

3. Is preoperative bridging with parenteral anticoagulation necessary?

In certain instances, patients who have a high thromboembolic risk and are discontinuing warfarin therapy may require bridging therapy with a low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH). If a patient’s CrCl is <30 mL/min, then UFH is the preferred agent for perioperative bridging.²¹

But before any decision is made, it’s best to have a good understanding of what the guidelines—and the literature—have to say.

Key studies and guidelines

The 2012 CHEST guidelines recommend providing bridge therapy for any patient at high risk for thromboembolism (>10% annual risk) and consideration of bridge therapy in the setting of moderate clotting risk (5%-10% annual risk), depending on specific patient and procedural risk factors (TABLE 1^3,5,6,9-11).³

In 2015, a landmark clinical trial was published that significantly shaped how patients taking warfarin are managed periprocedurally.²² The Bridge (Bridging anticoagulation in patients who require temporary interruption of warfarin therapy for an elective invasive procedure or surgery) trial was the first prospective, randomized controlled trial to assess the efficacy and safety of parenteral bridging in patients with AF taking warfarin and undergoing an elective surgery.

Patients in the trial received either dalteparin at a therapeutic dose of 100 IU/kg or a matching placebo administered subcutaneously bid from 3 days before the procedure until 24 hours before the procedure, and then for 5 to 10 days after the procedure. The incidence of thromboembolic events was not significantly lower in the dalteparin group than in the placebo group (0.3% vs 0.4%, respectively; P=.73), while major bleeding rates were nearly 3-fold higher in the dalteparin group (3.2% vs 1.3%; P=.005). The trial concluded that placebo “was noninferior to perioperative bridging with LMWH for the prevention of arterial thromboembolism and decreased the risk of major bleeding.”²²

When withholding anticoagulants, the goal is to have a low amount of anticoagulant effect (12%-25%) present during low-risk procedures and a nominal amount (3%-6%) present for high-risk procedures.

Patients excluded from the trial included those with a mechanical heart valve, or a recent (within 3 months) embolism, stroke, or TIA, and only 3% of enrolled patients would have been classified as having a high bleeding risk according to CHEST guidelines.^3,22

A prospective observational registry study produced similar findings and found that those patients who received bridging had more bleeding events and a higher incidence of myocardial infarction, stroke or systemic embolism, major bleeding, hospitalization, or death within 30 days than those who did not receive bridging.²³ Other retrospective cohort studies comparing bridging to no bridging strategies in patients taking warfarin for VTE, mechanical heart valves, or AF have also failed to show a reduction in the incidence of thrombotic events with LMWH bridging.^24,25

In 2016, the European Society of Cardiology suggested that “bridging does not seem to be beneficial, except in patients with mechanical heart valves.”²⁶ Similarly, the 2016 Anticoagulation Forum guidelines state that “most patients with VTE can safely interrupt warfarin for invasive procedures without bridge therapy,” and that bridge therapy should be “reserved for those at highest recurrent VTE risk (eg, VTE within the previous month; prior history of recurrent VTE during anticoagulation therapy interruption; undergoing a procedure with high inherent risk for VTE, such as joint replacement surgery or major abdominal cancer resection).”²¹ They go on to state that even in these high-risk groups, the clinical decision to use bridging therapy needs to carefully weigh the benefits against the potential risks of bleeding.²¹

Controversy also surrounds the intensity of LMWH bridging. The Anticoagulation Forum guidelines state that the use of prophylactic rather than therapeutic dose LMWH may be considered, while the CHEST guidelines do not make a firm recommendation regarding LMWH dose while bridging.^3,21 Ultimately, in patients who receive perioperative bridging with LMWH, the CHEST guidelines recommend that it should be stopped 24 hours prior to the procedure and resumed in accordance with the bleeding risk of the procedure (ie, prophylactic doses may be appropriate within 24 hours postprocedure, while full treatment doses may need to be delayed for 48 to 72 hours if surgical bleeding risk is high).³ UFH bridge therapy may be stopped 4 to 6 hours prior to surgery.³

DOACs. Given the rapid onset and relatively short half-lives of DOACs, use of a parenteral bridging agent is generally not necessary or recommended before or after an invasive procedure in patients taking a DOAC.²⁰

4. When should oral anticoagulation be resumed postoperatively, and at what intensity?

Warfarin can generally be resumed the same day as the procedure (in the evening), assuming there are no active bleeding complications.^3,11 Once fully reversed, it generally takes around 5 days for warfarin to become fully therapeutic, so it can be started soon after surgery without increasing the risk for early postoperative bleeding.²⁰