172 C – In patients on anticoagulants for a non-spine disorder, is perioperative bridging therapy necessary following cessation of anticoagulation prior to spine surgery?

Chadi Tannoury, Ryan Sutton.

Response/Recommendation: Perioperative bridging anticoagulation therapy is not superior to placebo in preventing thromboembolic events following cessation of anticoagulation prior to spine surgery. Additionally, bridging anticoagulation therapy can be associated with higher risk of major bleeding.

If a bridging therapy is contemplated in high-risk patients, and at the discretion of the treating physician, unfractionated heparin and low-molecular-weight heparin (LMWH) are reasonable options.

Strength of the Recommendation: Limited.

Rationale: Preoperative discontinuation of anticoagulation is commonly practiced mitigating the risks of bleeding and the formation of neuraxial hematoma^1-4. However, anticoagulant cessation may promote thromboembolic events in high-risk patients with valvular heart disease, atrial fibrillation, ischemic stroke, or venous thromboembolism (VTE).

The concept of bridging anticoagulation therapy was therefore hypothesized to minimize the risk of thromboembolic events in the perioperative period after discontinuation of anticoagulation. In a randomized double-blinded study, Douketis et al., reported comparable risk of arterial thromboembolic events with or without the use of perioperative bridging therapy LMWH vs. placebo, following cessation of warfarin in patients with atrial fibrillation⁵. They recommended against the use of bridging therapy due to a lack of superiority in preventing thromboembolic events, and the associated risk of major bleeding⁵. This study was not specific to spine surgery, however, and excluded patients with a history of mechanical heart valve, stroke, or VTE within 12 weeks prior to surgery⁵.

In another study, Steinberg et al., reported a higher rate of bleeding if bridging anticoagulation therapy (LMWH or unfractionated heparin [UH]) was implemented during perioperative interruption of anticoagulation therapy (odds ratio [OR] = 3.84)⁶. As a result, they recommended against the use of routine bridging therapy⁶. This study was also not specific to patients undergoing spine surgery⁶. In 2009, the North American Spine Society (NASS) issued clinical guidelines for the use of antithrombotic therapy in spine surgery, and the published consensus did not support an ideal perioperative bridging anticoagulation therapy⁷. The workgroup also suggested that the ideal time to withhold anticoagulation prior to surgery is unique to each drug’s clearance half-life⁷. If a bridging therapy is contemplated in high-risk patients, despite the limited evidence, the workgroup suggested that either intravenous UH or LMWH is a reasonable bridging anticoagulation agent following warfarin⁷. They argued, however, that intravenous heparin is more controllable and predictable than LMWH⁷. A bridging-intravenous-heparin-therapy should be stopped 4 – 6 hours (based on a half-life of 1 – 2 hours) prior to surgery and can be resumed 24 hours postoperatively3,8. Alternatively, bridging enoxaparin should be stopped 24 hours (based on a half-life of 4 – 7 hours) prior to surgery and can be resumed 12 – 24 hours postoperatively³.

In conclusion, despite the limited evidence related to spine surgery, perioperative bridging anticoagulation therapy is not superior to placebo in preventing thromboembolic events following cessation of anticoagulation prior to surgery. Additionally, bridging therapy can be associated with higher risk of major bleeding. If a bridging therapy is contemplated in high-risk patients, UFH and LMWH are reasonable options.

References:

1. Rokito SE, Schwartz MC, Neuwirth MG. Deep vein thrombosis after major reconstructive spinal surgery. Spine. Apr 1 1996; 21(7): 853-8; discussion 859.
2. Coumadin. Princeton, NJ: Bristol-Myers Squibb Company; 1954.
3. Narouze S, Benzon HT, Provenzano D, Buvanendran A, De Andres J, Deer T, Rauck R, Huntoon MA. Interventional Spine and Pain Procedures in Patients on Antiplatelet and Anticoagulant Medications (Second Edition): guidelines from the American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, the American Academy of Pain Medicine, the International Neuromodulation Society, the North American Neuromodulation Society, and the World Institute of Pain. Reg Anesth Pain Med. 2018; 43: 225-262.
4. Young EY, Ahmadinia K, Bajwa N, Ahn NU. Does chronic warfarin cause increased blood loss and transfusion during lumbar spinal surgery? Spine J. 2013; 13:1253-8.
5. Douketis JD, Spyropoulos AC, Kaatz S, Becker RC, Caprini JA, Dunn AS, Garcia DA, Jacobson A, Jaffer AK, Kong DF, Schulman S, Turpie AGG, Hasselblad V, Ortel TL. Perioperative bridging anticoagulation in patients with atrial fibrillation. N Engl J Med. 2015;373(09):823–833
6. Steinberg BA, Peterson ED, Kim S, Thomas L, Gersh BJ, Fonarow GC, Kowey PR, Mahaffey KW, Sherwood MW, Chang P, Piccini JP, Ansell J. Outcomes Registry for Better Informed Treatment of Atrial Fibrillation Investigators and Patients. Use and outcomes associated with bridging during anticoagulation interruptions in patients with atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 2015 Feb 3; 131(5): 488-94. 
7. Bono CM, Watters WC 3rd, Heggeness MH, Resnick DK, Shaffer WO, Baisden J, Ben-Galim P, Easa JE, Fernand R, Lamer T, Matz PG, Mendel RC, Patel RK, Reitman CA, Toton JF. An evidence-based clinical guideline for the use of antithrombotic therapies in spine surgery. Spine J. 2009 Dec; 9(12): 1046-51.
8. Horlocker TT, Vandermeuelen E, Kopp SL, Gogarten W, Leffert LR, Benzon HT. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Fourth Edition). Reg Anesth Pain Med 2018; 43: 263-309.