Clinicians should initiate a bridge when a patient’s INR falls to less than 2.0 and discontinue the UFH bridge four to six hours prior to the procedure.10 The recent update to the guidelines now states that LMWH should be discontinued 24, instead of 12, hours prior to the procedure.3
When to restart UHF or LMWH bridge post-procedure. The type of procedure being performed dictates when bridging anticoagulation should resume. In patients who have undergone surgeries that involve high bleeding risk, LMWH should not be administered until 48-72 hours post-surgery (Grade 2C evidence).3 For those patients undergoing surgeries with low bleeding risk, bridging should be resumed approximately 24 hours after the procedure.
Of note, enoxaparin administered in one single daily dose, as compared to divided doses, is associated with a greater risk of post-operative bleeding. UFH bridging should resume post-operatively without a bolus dose at 24 hours in low-risk bleeding cases or 48-72 hours in high-risk bleeding cases (Grade 2C evidence).3
On occasion, unanticipated adjustments to surgical cases—or complications—change the previously determined post-operative bleeding risk. In these instances, the hospitalist and surgeon/proceduralist should review the case and reassess the bleeding risk prior to employing bridging anticoagulation protocols.
When to restart long-term vitamin K antagonists (VKA) post-procedure. In most instances, regardless of pre-operative bleeding risk stratification, the resumption of VKA may occur once post-operative hemostasis has been achieved and the patient has been instructed to resume eating by the proceduralist or surgeon. This most often occurs on the calendar day following surgery, because it takes approximately five days for an INR to achieve therapeutic levels.
Back to the Case
The patient’s history of prosthetic valve with stroke within the preceding six months stratified her to a high thrombotic risk category. Given the high risk of thrombosis, the decision was made to bridge with LMWH. The hospitalist discontinued LMWH 24 hours prior to surgery, and INR was checked on the morning of the procedure.
Although the patient underwent the operation without significant bleeding, the adjustment from an exploratory laparoscopy to an open laparotomy increased her post-operative bleeding risk from medium to high. Therefore, bridging anticoagulation with LMWH was resumed no sooner than 48 hours after the operation. Her warfarin was restarted on the day following surgery, once she resumed her diet.
Hospitalists must understand both the pre- and post-procedure thrombotic risks, as well as the pre- and post-procedural bleeding risks, when determining the selection and logistics of initiation and cessation of antithrombotic bridging for inpatients.
Drs. McCormick, Carbo, and Li are hospitalists at Beth Israel Deaconess Medical Center in Boston. Dr. Kerbel is a hospitalist at the University of California Los Angeles.
- BRIDGE Study Investigators. Bridging anticoagulation: is it needed when warfarin is interrupted around the time of a surgery or procedure? Circulation. 2012;125(12):e496-498.
- Ansell J, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 Suppl):160S-198S.
- Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e326S-350S.
- Kovacs MJ, Kearon C, Rodger M, et al. Single-arm study of bridging therapy with low-molecular-weight heparin for patients at risk of arterial embolism who require temporary interruption of warfarin. Circulation. 2004;110(12):1658-1663.
- Woods K, Douketis JD, Kathirgamanathan K, Yi Q, Crowther MA. Low-dose oral vitamin K to normalize the international normalized ratio prior to surgery in patients who require temporary interruption of warfarin. J Thromb Thrombolysis. 2007;24(2):93-97.
- Ortel TL. Perioperative management of patients on chronic antithrombotic therapy. Blood. 2012;120(24):4699-4705.
- Kaatz S, Douketis JD, Zhou H, Gage BF, White RH. Risk of stroke after surgery in patients with and without chronic atrial fibrillation. J Thromb Haemost. 2010;8(5):884-890.
- Siegal D, Yudin J, Kaatz S, Douketis JD, Lim W, Spyropoulos AC. Periprocedural heparin bridging in patients receiving vitamin K antagonists: systematic review and meta-analysis of bleeding and thromboembolic rates. Circulation. 2012;126(13):1630-1639.
- Lee AY, Levine MN, Baker RI, et al. Low-molecular-weight heparin versus a coumarin for the prevention of recurrent venous thromboembolism in patients with cancer. N Engl J Med. 2003;349(2):146-153.
- Hirsh J, Raschke R. Heparin and low-molecular-weight heparin: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(3 Suppl):188S-203S.