Interrupting warfarin therapy

Management of patients on warfarin undergoing invasive procedures

When considering how to manage patients receiving warfarin who require surgery, the risk of thrombosis if warfarin is stopped or modified needs to be balanced relative to the risk of bleeding if continued.

The Patient Blood Management (PBM) Guidelines: Module 2 – Perioperative1 provide some guidance with the following recommendation and practice point.

Recommendation 10:

In patients undergoing minor dental procedures, arthrocentesis, cataract surgery, upper gastrointestinal endoscopy without biopsy or colonoscopy without biopsy, warfarin may be continued (Grade B).

Practice point 10:

In patients receiving warfarin who are scheduled for elective noncardiac surgery or other invasive procedures (excluding minor procedures—see Recommendation 10); specific management according to current guidelines is required (e.g. guidelines from the American College of Chest Physicians2 and the Australasian Society of Thrombosis and Haemostasis3).

The Australasian Society of Thrombosis and Haemostasis (ASTH) guidelines provide a suggested perioperative arterial and venous thromboembolism risk stratification. Using this risk stratification ASTH provide management recommendations both before and after surgery for patients on long-term warfarin therapy undergoing invasive procedures.3

Key points from the ASTH guidelines in relation to perioperative management include the following3:

  • Surgery can be conducted with minimal increased risk of bleeding if INR ≤ 1.5.
  • For minor procedures where bleeding risk is low, warfarin may not need to be interrupted.
  • If necessary, warfarin can be withheld for 5 days before surgery, or intravenous vitamin K1 can be given the night before surgery.
  • Prothrombinex-VF use for warfarin reversal should be restricted to emergency settings.
  • Patients at high risk for arterial and venous thromboembolism should be considered for bridging anticoagulation with therapeutic low molecular weight heparin (LMWH) or an infusion of unfractionated heparin.
Reference
  1. National Blood Authority. Patient Blood Management Guidelines: Module 2 – Perioperative. Australia, 2011.
  2. Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ, Svensson PJ, Veenstra DL, Crowther M, Guyatt GH; American College of Chest Physicians. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb;141(2 Suppl):e152S-84S.
  3. Tran HA, Chunilal SD, Harper PL, Tran H, Wood EM, Gallus AS. An update of consensus guidelines for warfarin reversal. MJA 2013;198(4):198–199.