Perioperative Anticoagulation Management

Introduction to Perioperative Anticoagulation

• The American College of Chest Physicians recommends stopping warfarin 5 days before surgery to allow INR to normalize to <1.5 at the time of surgery, with bridging therapy using heparin or LMWH reserved for patients at high risk of thromboembolism 1, 2

Preoperative Management

• For most patients, a 5-day interruption of warfarin is sufficient to normalize the INR, with only 7% of patients having an INR >1.5 on the day of surgery, according to the American College of Chest Physicians 1
• The American College of Chest Physicians suggests checking INR the day before surgery to ensure it has normalized (<1.5) 1
• If INR remains elevated (>1.5) the day before surgery, the American College of Cardiology recommends considering administering 1-2.5 mg of vitamin K orally to expedite INR normalization 2

Patient Selection for Bridging Therapy

• The American College of Cardiology identifies high-risk patients for thromboembolism, including those with mechanical mitral valve, prosthetic valve with prior thromboembolism, recent (<3 months) venous thromboembolism, or atrial fibrillation with prior stroke or multiple risk factors (CHADS₂ score >4) 2
• The following table summarizes the thrombotic risk categories:

Bridging Therapy

• The American College of Cardiology recommends beginning therapeutic-dose heparin or LMWH 2-3 days after stopping warfarin (when INR falls below therapeutic range) 2
• The American College of Cardiology suggests using LMWH: 100 U/kg subcutaneously every 12 hours or UFH: 15,000 U subcutaneously every 12 hours or continuous IV infusion (1300 U/hour) for highest-risk patients 2
• The American College of Cardiology advises stopping IV UFH 5 hours before surgery and giving the last dose of LMWH 24 hours before surgery 2
• Bridging therapy should be started 2 days after stopping warfarin, with the last dose of LMWH administered at least 24 hours prior to the procedure, as recommended by the European Society of Cardiology and American Society for Gastrointestinal Endoscopy 3, 4

Postoperative Management

• The American College of Chest Physicians recommends resuming warfarin 12-24 hours after surgery (evening of or next morning) when hemostasis is adequate, using the patient's usual maintenance dose 1
• The American College of Chest Physicians notes that the time to reach therapeutic INR after resuming warfarin is typically 5-10 days 1
• For high-risk patients, the American College of Cardiology suggests resuming prophylactic-dose heparin or LMWH 12-24 hours after surgery, then increasing to therapeutic dose when hemostasis is secure, and continuing bridging until INR returns to therapeutic range 2
• After the procedure, warfarin should be resumed with the usual daily dose, and INR should be checked one week later to ensure adequate anticoagulation, as advised by the American Society for Gastrointestinal Endoscopy and British Society of Gastroenterology 3, 4
• For patients who required bridging therapy, LMWH should be restarted the day after the procedure and continued until INR returns to the therapeutic range, according to the European Society of Gastrointestinal Endoscopy and American College of Cardiology 3, 4

Special Considerations

• The American College of Cardiology recommends considering using tranexamic acid or aminocaproic acid mouthwash without interrupting anticoagulation for dental procedures 2
• For patients undergoing colonoscopy with anticipated polypectomy or high-risk interventions, warfarin should be discontinued 5 days before the procedure and INR checked prior to ensure it is <1.5, as recommended by the American Society for Gastrointestinal Endoscopy, British Society of Gastroenterology, and European Society of Gastrointestinal Endoscopy 3, 4
• For low-risk procedures such as diagnostic colonoscopy with or without biopsies, warfarin can be continued, with INR within therapeutic range in the week prior to procedure, as recommended by the American College of Cardiology, American Heart Association, and European Society of Cardiology 3, 5, 4
• High-risk procedures, including colonoscopy with anticipated polypectomy, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD), require warfarin discontinuation due to significantly increased bleeding risk, according to the American Society for Gastrointestinal Endoscopy and British Society of Gastroenterology 3, 4
• Patients on warfarin have an increased risk of post-procedure bleeding compared to non-anticoagulated patients, even when warfarin is temporarily discontinued, with a prevalence of polyps found in 22.5-42% of colonoscopies, making it prudent to plan for possible polypectomy in most cases 3
• Post-polypectomy bleeding rates range from 0.8-23% in patients on anticoagulation compared to 0.07-1.7% in non-anticoagulated patients, highlighting the need for careful management of anticoagulation therapy 3
• The American College of Gastroenterology recommends that patients on warfarin have their INR checked during the week before the procedure to ensure it is within therapeutic range, and if INR is above therapeutic range but <5, reduce daily warfarin dose until INR normalizes 3