Ask the expert John L. Petrini, Antithrombotic agents during endoscopy MD, FASGE
1. Q: Do you routinely discontinue warfarin in patients with chronic atrial fibrillation without valvular heart disease or prior embolic events prior to: Ask the expert features A. Routine screening colonoscopy? questions submitted by B. Colonoscopy for a positive fecal occult blood test? C. Endoscopy for iron deficiency anemia? members, with answers D. Colonoscopy for prior adenomatous polyp(s)? provided by ASGE A: The decision to stop anticoagulation depends on the perceived risk of a thromboembolic event. If the risk is physician experts. ASGE’s high (e.g., elderly patient, chronic atrial fibrillation, valvular heart disease or prior thromboembolic events), the morbidity and mortality associated with interrupting or modifying anticoagulation is substantial, which, in Publications Committee my opinion, is unacceptable. Therefore, in those patients, I do not recommend stopping anticoagulation before identifies authors and routine screening colonoscopy (A). topics for the column. In fact, I do not recommend stopping anticoagulation for colonoscopy in patients with any of the above In this issue, ASGE indications. The decision to modify or stop anticoagulation for patients who have positive fecal occult blood 2008-09 Past President, tests or iron deficiency anemia is left to the cardiologist or primary care physician. For patients undergoing surveillance colonoscopy for prior adenomatous polyps, I do not interrupt anticoagulation for high-risk patients John L. Petrini, MD, and advise them of the slightly increased risk of bleeding associated with removing polyps while on FASGE, responds an anticoagulant. to questions on antithrombotic agents 2. Q: What are your thoughts on starting aspirin and/or clopidogrel (Plavix) after a polypectomy for a 1 cm or larger pedunculated polyp? during endoscopy. A: The risk of rebleeding after polypectomy is increased only minimally in patients who take aspirin or Dr. Petrini serves as clopidogrel. If the medications are necessary to prevent thrombosis of an intra-arterial stent, interrupting staff physician and chief therapy is not recommended. The use of endoscopic clipping devices and/or mucosal loops to reduce the risk of the Department of of postpolypectomy bleeding is still not established. Gastroenterology at the 3. Q: Whether and when to stop clopidogrel for endoscopic procedures seems to be the largest ongoing Sansum Clinic Inc. in Santa controversy. What do you advise for the hospitalized patient: Barbara, Calif. Dr. Petrini A. Undergoing percutaneous endoscopic gastrostomy (PEG) tube placement on both aspirin has no disclosures. and clopidogrel? B. With acute lower GI bleeding on aspirin and clopidogrel undergoing colonoscopy? A: Each clinical situation is different and must be evaluated individually. Patients who are on both aspirin and clopidogrel are at increased risk of prolonged bleeding after any vascular disruption. Therefore, any procedure that creates a risk of bleeding may be associated with increased or protracted bleeding when these agents are used. For PEG placement, the risk of bleeding is relatively low, but bleeding may be inaccessible (i.e., intraabdominal). Therefore, I routinely interrupt antiplatelet therapy for patients who require PEG placement, unless the risk of interruption is so great that to do so would put the patient at significant jeopardy. The needs of the PEG are then explored with the patient and/or family, and if all parties agree, I place the PEG, recognizing the increased risk of bleeding. For patients who have an acute lower GI bleed, typically, by the time I am consulted, they have often had their medications stopped. Once the source is identified and treated, I then resume therapy.
4. Q: How long after a therapeutic procedure (e.g., esophageal dilation, colonoscopic polypectomy, endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy) should a patient remain off an antithrombotic or an antiplatelet agent, such as aspirin, warfarin, clopidogrel, heparin or fondaparinux (Arixtra)?
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ASGE News March | April 2010 1 Ask the expert continued from page 1 A: This question strikes at the concern I have regarding our current clinical recommendations. The recommendation is to begin all anticoagulation and/or antiplatelet therapy immediately after the procedure. (This assumes there is no substantial bleeding at the time of the procedure.) In the case of unfractionated heparin, the recommendation is to wait two to six hours before restarting and to restart low-molecular-weight heparin after the procedure. My argument against stopping the therapy is that you can address the bleeding that occurs during the procedure. Delayed bleeding will typically occur when patients are back on their antiplatelet or anticoagulation therapy, so interrupting therapy only helps reduce bleeding that is eminently treatable at the time of the procedure. 5. Q: A patient who underwent an angioplasty with a drug-eluting coronary artery stent placement within the past one month and who is now on both aspirin and clopidogrel, has a major acute bleed from a duodenal ulcer. The patient then undergoes endotherapy with epinephrine injection and hemoclip application. He is placed on pantoprazole by intravenous infusion for 72 hours. How soon should aspirin and clopidogrel be restarted? A: Due to the substantial risk of thrombosis of a recently placed drug-eluting stent, we would restart aspirin therapy once the GI bleeding has been controlled. Restarting aspirin definitely places the patient at risk for recurrent bleeding and ulceration, but that risk has to be weighed against the risk of thrombosis and an approximately 40 percent or so risk of myocardial infarction. Maintaining proton pump inhibitor therapy should help to minimize the risk of ulceration from aspirin. Restarting clopidogrel as soon as possible would also be advised. 6. Q: If a 70-year old woman with paroxysmal atrial fibrillation and a history of a hyperplastic colonic polypectomy three years previously is sent for repeat colonoscopy, is it reasonable to stop warfarin for two to three days and obtain stool for occult blood rather than perform an unnecessary colonoscopy? A: I am puzzled by this question, since patients who have had a hyperplastic colonic polyp are not at increased risk for cancer and, therefore, should not have a colonoscopy for five years if they are at high risk due to family history of colon cancer or a previous neoplastic polyp or 10 years if they are at average risk. Stool tests for occult blood are not recommended in this instance and should never replace surveillance colonoscopy due to their low sensitivity and specificity. 7. Q: In a patient who must continue on clopidogrel, in what circumstances would you consider performing: A. PEG tube placement. B. Endoscopic stricture dilation. C. ERCP with sphincterotomy. D. Colonoscopy with polypectomy of polyps < 0.5 cm. E. Colonoscopy with polypectomy of polyps between 0.5 cm to 1 cm. F. Colonoscopy with polypectomy of polyps > 1 cm.
A: I would consider performing all of these procedures if clinically indicated. The major controversial one in my opinion is PEG placement due to the risk of bleeding that is inaccessible (i.e., intraabdominal). However, I would be prepared to provide transfusions of platelets if necessary in all circumstances. With regard to polypectomy, I do not routinely stop or adjust clopidogrel in these patients. I would answer the exact same way if the antiplatelet agent were aspirin. 8. Q: I know that the 2009 ASGE guidelines, Management of Antithrombotic Agents for Endoscopic Procedures, state that patients undergoing colonoscopy with polypectomy need not discontinue aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). My major concern is that previous studies on the risk of post-polypectomy bleeding in patients on aspirin or NSAIDs have all been small studies and, therefore, statistically underpowered to detect a small but real risk of postpolypectomy bleeding. A: Although the studies are small, the risks of bleeding appear to be small as well, and in particular, the risk of fatal bleeding is quite small. Therefore, the decision to withhold aspirin and other NSAIDs should be based upon the patient’s condition and not the procedure.
9. Q: As mentioned in the previous question, the 2009 ASGE guidelines for antithrombotic agents state that we do not have to hold aspirin before colonoscopy with polypectomy. If we follow these guidelines and the patient has a massive post-polypectomy bleed within a week and dies, would the patient’s family have no grounds to sue for medical malpractice, because we are following ASGE guidelines? Would you ever recommend holding aspirin before colonoscopy with polypectomy? If so, in what circumstances would you recommend holding aspirin (either before or after polypectomy)? continued on page 3 ASGE News March | April 2010 2 Ask the expert continued from page 2 A: There is no way to absolutely protect yourself against a malpractice suit. Practicing according to established guidelines can help to reduce the likelihood that a suit will be successful, but the guidelines cannot protect you against a malpractice claim.
Do you think you would be less likely to be sued if the patient had a stroke or heart attack due to withholding the aspirin? Do you think that if a patient not on aspirin has a major fatal bleed after polypectomy, that you will be less likely to be sued? What if the patient bleeds 14 days after the procedure when you have started aspirin therapy again?
I do not recommend withholding anticoagulation or antiplatelet therapy in patients who have a significant risk of a life-threatening thromboembolic event. I do, however, counsel the patient and the patient’s family regarding the risks associated with either course of action and allow them to participate in the decision- making process.
10. Q: In a patient on intravenous (IV) heparin who just had a PEG placed, when and how would you recommend restarting the IV heparin?
A: I typically do not use IV heparin drips but rather subcutaneous injections of low-molecular-weight heparin. I would start the injections after the procedure. The need to start IV heparin and whether to bolus or start a drip depend on the rationale for using the heparin. The heparin is usually started two to six hours after the procedure.
11. Q: In a patient with acute GI bleeding who is on warfarin, at what level of internationalized normalized ratio (INR) do you feel that it is safe to perform esophagogastroduodenoscopy and colonoscopy to evaluate for the bleeding source? Does the INR have to be within the normal range before endoscopy is performed?
A: I do not wait for the INR to normalize if the patient is actively bleeding and potentially needs endoscopic therapy. The situation is similar to performing endoscopic variceal banding on a Childs class C patient. If we waited for the INR to normalize, we would never do the procedure.
12. Q: Are there any endoscopic tips that you have when performing polypectomy of a 1 cm colonic polyp in a patient taking aspirin, clopodogrel or both aspirin and clopodogrel?
A: The removal of polyps on antiplatelet agents has been addressed in the 2009 ASGE guidelines, and routinely stopping the antiplatelet therapy is not advised. In patients who need antiplatelet therapy, I routinely perform polypectomy with a cold snare, snare cautery, saline-assisted or piecemeal, as indicated. The use of injectible agents, such as epinephrine or saline, has not been shown to reduce the incidence of late bleeding. The use of constriction devices, such as clips and bands, has shown mixed results.
13. Q: Should I recommend to my patients undergoing endoscopy that they continue their anticoagulation therapy for atrial fibrillation associated with valvular heart disease or a prosthetic heart valve? A: A retrospective review (Blacker DJ, Wijdicks EFM, McClelland RL. Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy. Neurology 2003; 61: 964-9.) suggested that the periendoscopic risk of a substantial thromboembolic event, (half of which result in permanent morbidity or death), is approximately 1 percent when anticoagulant therapy is modified. This figure includes patients who have not had prior embolic events. Even bridging therapy with low-molecular-weight or unfractionated heparin is not universally protective. There were no such events when anticoagulation was continued. However, if you stop the anticoagulant therapy in these patients, bridging therapy is recommended.
The information presented in Ask the expert reflects the opinions of the author and does not represent the position of ASGE. ASGE expressly disclaims any warranties or guarantees, express or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.
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AdditIonal ASGE Resources
l Guideline on Management of Antithrombotic Agents for Endoscopic Procedures New! ASGE released the new guideline, Management of Antithrombotic Agents for Endoscopic Procedures, which appeared in the December 2009 issue of GIE: Gastrointestinal Endoscopy. The guideline, developed by the ASGE Standards of Practice Committee, states that aspirin and/or other nonsteroidal anti-inflammatory drugs (NSAIDs) may be continued for all elective endoscopic procedures.
l Pocket cards now available New! New for 2010, the ASGE Antithrombotic Agents pocket cards include information on the management of antithrombotic agents in the elective and urgent endoscopic settings, procedure risk for bleeding, condition risk for thromboembolic events and periprocedural management of warfarin for patients with atrial fibrillation or valvular heart disease, who are undergoing elective endoscopy. The ASGE member price is $10 and the non-member price is $15 for 25 cards. Click on pocket cards for more information.
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