南加大洛杉磯分校Keck醫學院、加州Santa Barbara Sansum診所的John L. Petrini醫師在編輯評論中寫道，目前，決定續用或停用抗血小板治療劑尚無明確解答，也未建立標準實務規範。內視鏡醫師和他們的病患必須瞭解，決定改變用來減少支架阻塞風險的藥物，目標應是預防傷害。本研究對於「這些病患續用抗血小板藥物治療是最佳方式且不會有傷害」的看法提供了部分支持。
研究作者們與Petrini醫師皆宣告沒有相關財務關係。
Routinely Stopping Clopidogrel Before Colonoscopy/Polypectomy May Not Be Needed
By Laurie Barclay, MD
Medscape Medical News
May 26, 2010 — Routinely stopping clopidogrel before colonoscopy/polypectomy may not be needed, according to the results of a single-center, retrospective study reported in the May issue of Gastrointestinal Endoscopy.
"There are no data on the clopidogrel-associated risk of [postpolypectomy bleeding (PPB)], and the benefit of holding clopidogrel 7 to 10 days before polypectomy remains unproven," study coauthor Uma Murthy, MD, from Syracuse Veterans Affairs Medical Center in New York, NY. "At [our institution], clopidogrel is not routinely held before colonoscopy and polypectomy."
The goal of the study was to determine the PPB rate and outcome and to identify risk factors predicting PPB in patients taking clopidogrel. Univariate analysis allowed comparison of demographic and clinical factors, polyp characteristics, polypectomy techniques, and postpolypectomy events in 142 patients (375 polypectomies) taking clopidogrel (cases) and 1243 patients (3226 polypectomies) not taking clopidogrel (controls). Independent risk factors associated with PPB, hospitalization, and mortality were determined with stepwise logistic regression analyses.
Cases and controls had similar immediate (intraprocedural) bleeding rate (2.1% vs 2.1%), but the clopidogrel group had a higher delayed (postprocedural) rate of PPB (3.5% vs 1.0%; P = .02), as well as of significant delayed bleeding requiring hospitalization and transfusion/intervention (2.1% vs 0.4%; P = .04). There were no deaths, and both groups had similar duration of hospitalization and interventions for PPB.
Use of clopidogrel alone was not an independent risk factor for PPB. The only significant risk factors associated with PPB were concomitant use of clopidogrel and aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs; odds ratio [OR], 3.7; 95% confidence interval [CI], 1.6 - 8.5) and the number of polyps removed (OR, 1.3; 95% CI, 1.2 - 1.4).
"This study elucidates the risk of bleeding in patients undergoing colonoscopic polypectomy on uninterrupted clopidogrel therapy," Dr. Murthy said. "We found that the use of clopidogrel alone was not associated with higher rates of PPB, but the risk increased when clopidogrel was concomitantly used with aspirin or other NSAIDs."
Limitations of this study include retrospective design and small number of patients with PPB.
"The PPB rate is significantly higher in patients undergoing polypectomy while taking clopidogrel and concomitant aspirin/[NSAIDs]; however, the risk is small and the outcome is favourable," the study authors write. "Routine cessation of clopidogrel in patients before colonoscopy/polypectomy is not necessary."
The investigators also pointed out that discontinuing clopidogrel in patients with cardiovascular and atherothrombotic diseases is associated with a greater risk for acute ischemic events, particularly when clopidogrel is stopped during the first 90 days of therapy. Therefore, they concur with guidelines suggesting delaying elective or screening colonoscopy until 6 to 12 months after coronary intervention.
"At the current time, the decision to continue or discontinue antiplatelet therapy is not firmly resolved and a standard of practice is not established," wrote John L. Petrini, MD, FASGE, from Sansum Clinic in Santa Barbara, California, and Keck School of Medicine, University of Southern California, Los Angeles, in an accompanying editorial. "Endoscopists and their patients need to be aware of who is being prevented from harm in the decision to alter medications given to reduce the risk of stent occlusion. [This study] offers some support for those of us who believe that continuing antiplatelet therapy in these patients may be the best way of doing no harm."
The study authors and Dr. Petrini have disclosed no relevant financial relationships.
