Proper Preparation Strategies for Patients On Chronic Anticoagulation Undergoing Endoscopy

One of the most common clinical challenges that endoscopists encounter is how to properly manage antithrombotic agents in patients undergoing endoscopic procedures. Optimal management requires strategies individualized to specific patients. Physicians must consider the bleeding risk of the endoscopic procedure being performed, the underlying patient condition necessitating the antithrombotic therapy and the specific characteristics of the antithrombotic medication. Whether the planned endoscopic procedure is an elective or an urgent one also influences the management strategy.

In order to formulate an effective strategy one needs to understand the bleeding risk of the endoscopic procedure. Low-risk procedures include upper endoscopy and colonoscopy with or without mucosal biopsy, endoscopic retrograde cholangiopancreatography (ERCP), including stent placement, enteroscopy, endoscopic ultrasound (EUS) without fine-needle aspiration (FNA), and capsule endoscopy. High-risk procedures include polypectomy (especially polyps over 1 cm), ERCP with sphincterotomy, esophageal dilation, percutaneous endoscopic gastronomy placement, and EUS with FNA.

The patient’s underlying condition determines the thrombotic risk if the antithrombotic medication is withheld. High-risk conditions for thrombosis include recently placed coronary stents, acute coronary syndrome, mechanical mitral valves, atrial fibrillation with a CHADS2 score > 2 and recent venous thromboembolism events. Low-risk conditions include mechanical aortic valves without other risk factors and uncomplicated atrial fibrillation (CHADS2 score < 2).

Aspirin and the thienopyridines (P2Y12 inhibitors) are the main anti-platelet agents. In patients on daily aspirin, there is not an increase in bleeding after upper endoscopy or colonoscopy including with biopsy or removal of small polyps. I do not stop aspirin when given for secondary prophylaxis after a prior cardiac or neurological event, as thrombotic risks from stopping include myocardial infarctions, CVA and death. The thienopyridines inhibit the binding of ADP to the P2Y12 receptor and subsequent activation of the glycoprotein IIb/IIIa receptor and are often given along with aspirin as part of dual antiplatelet therapy (DAPT). High-risk conditions treated with DAPT include within three months of acute coronary syndrome, within one month of a bare metal stent and within 12 months of a drug eluting stent. Patients on DAPT for these high-risk conditions should not have therapy interrupted except in emergencies. In patients maintained on DAPT, studies have shown that the combination of aspirin and a thienopyridine has increased risk for bleeding after polypectomy whereas aspirin or a thienopyridine alone does not cause increased bleeding. Thus, for patients undergoing elective endoscopic procedures, continue aspirin but hold the thienopyridine for one week if possible. I confirm that this is acceptable with the prescribing physician.


The patient’s underlying condition determines the thrombotic risk if the antithrombotic medication is withheld.


Anticoagulants include warfarin and the direct oral anticoagulants (DOACs). Warfarin inhibits the vitamin K dependent clotting factors as well as protein C and S. If the anticoagulation is temporary and endoscopic procedure is elective, I delay the procedure until the warfarin can be stopped. However, no adjustments in anticoagulation are needed in low-risk endoscopic procedures if the INR is not supratherapeutic. Colonoscopy with cold snare polypectomy appears safe in polyps up to 10 mm. In high-risk procedures in patients on warfarin for a low-risk condition, the anticoagulation can be held before the procedure. In patients on warfarin for high-risk conditions undergoing high-risk endoscopic procedures, the warfarin should be discontinued before the procedure and bridging should be considered with standard or low-molecular-weight heparin. The DOACs directly inhibit factor Xa (e.g. rivaroxaban, apixaban and edoxaban) or thrombin (e.g. dabigatran). The oral medications quickly result in anticoagulation and also are relatively quickly cleared in patients with normal renal function. These drugs can be held for one day before low-risk endoscopic procedures and for two to three days before high-risk procedures if renal function is normal, but for more prolonged times with renal dysfunction.

In patients with acute GI bleeding on antithrombotic agents, the management depends on the severity of the bleeding and all of the previously discussed factors. Aspirin can be initially withheld, but should be restarted if given for secondary prophylaxis with one day for low-risk bleeding and within three to seven days for high-risk bleeding, such as bleeding requiring endoscopic therapy. Endoscopic bleeding therapy can be effectively performed with INR’s < 2.5 and reversal, if needed, is best done with prothrombin complex concentrate. For patients bleeding on DOACs, stopping the DOAC is sufficient in most, although there is an available reversal agent for dabigatran (e.g. idarucizumab) and soon there may be other Xa inhibitors reversal agents available.

All endoscopists need to be familiar with management strategies of antithrombotic medications in patients undergoing endoscopic procedures. An understanding of the bleeding risks of the endoscopic procedure, the thrombotic risk of the patient and the antithrombotic agents allows for an individualized and safe management strategy.

Dr. Saltzman has no conflicts to disclose.

References
1. Abraham, N.S.Management of antiplatelet agents and anticoagulants in patients with gastrointestinal bleeding. Gastrointest Endosc Clin N Am. 2015;25(3):449-62.
2. ASGE Standards of Practice Committee, Acosta , R.D., Abraham, N.S., Chandrasekhara, V. et al, Managing antithrombotic agents during endoscopy. Best Pract Res Clin Gastroenterol. 2016;30(5):679-687.
3. Greenwald, D.A. Colonoscopy is associated with a reduced risk for colon cancer and mortality in patients with inflammatory bowel diseases. Clin Gastroenterol Hepatol. 2015;13(2):322–329.
4. Horiuchi, A., Nakayama, Y., Kajiyama, M. et al, Removal of small colorectal polyps in anticoagulated patients: a prospective randomized comparison of cold snare and conventional polypectomy. Gastrointest Endosc. 2014;79(3):417-23.
5. Sung, J.J., Lau, J.Y., Ching, J.Y. et al, Continuation of low-dose aspirin therapy in peptic ulcer bleeding: a randomized trial. Ann Intern Med. 2010;152:1-9.

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