DDW 2011: Study Examines Colonoscopy Bleeding Risk with Clopidogrel vs. CV Risk Without

May 11, 2011
Walter Alexander

Cardiovascular risks associated with discontinuing clopidogrel before elective colonoscopy exceed the risks of post-polypectomy bleeding.

Cardiovascular risks associated with discontinuing clopidogrel before elective colonoscopy exceed the risks of post-polypectomy bleeding.

“We speculate that the cardiovascular risks of routinely discontinuing clopidogrel may well exceed any excess risk of post-polypectomy bleeding,” stated Fatema Uddin, MD, a fellow in the division of digestive and liver diseases at University of Texas Southwestern Medical Center, Dallas, TX. Her statement, given in an oral presentation at Digestive Disease Week 2011, was based on findings from a retrospective study of all patients undergoing colonoscopy with polypectomy at the Dallas VA Hospital between July 2008 and December 2009.

Uddin noted that the majority of adults age 60 years and older have one or more type of cardiovascular disease, with 20% requiring anticoagulation or antiplatelet agents (ie, aspirin, warfarin, clopidogrel). ASGE (American Society for Gastrointestinal Endoscopy) guidelines recommend considering withholding clopidogrel for 7-10 days prior to high-risk procedures like polypectomy. Stopping these agents, however, entails risk for myocardial infarction, cerebrovascular accidents, thromboembolic events, and stent thrombosis. Stent thrombosis among patients who have received a drug-eluting stent, in particular, has been shown to carry a high mortality risk. Data are lacking, however, on the risk of bleeding if clopidogrel is continued during polypectomy.

Uddin noted that because physicians at the Dallas VA Hospital have judged the cardiovascular risks of discontinuing clopidogrel prior to elective colonoscopy to exceed the risks of post-polypectomy bleeding, the procedure there is to not routinely discontinue clopidogrel. Uddin and colleagues evaluated the safety of continuing clopidogrel during colonoscopy when polypectomy is performed.

In the study, colonoscopy with polyp removal was performed in 118 patients on clopidogrel and 1,849 patients not on clopidogrel. A logistic regression analysis revealed no significant difference in the frequency of delayed post-polypectomy bleeding (PPB) between clopidogrel users and non-users (0.8% versus 0.3%, p=0.37, unadjusted OR=2.63, 95% CI:0.31-22). There were significant differences between clopidogrel users and non-users in the frequency of coronary artery disease (94.1% vs. 24.2%), aspirin use (78% vs. 27.9%), age (64.9 vs. 62.4), and lung disease (24.6% vs. 13.4%). Matched analysis taking these into account also revealed no significant difference in PPB rates between clopidogrel users and non-users (0.9% vs. 0%, p=0.99). Importantly, the outcomes among patients who did have bleeding were without major consequences.

Uddin concluded, “The delayed PPB rate for our patients taking clopidogrel was less than 1% (1 PPB). PPB rates did not differ significantly between the clopidogrel users and non-users, even after controlling for potential confounders by propensity scoring. We speculate that the cardiovascular risks of routinely discontinuing clopidogrel before elective colonoscopy may well exceed any excess risk of PPB.”

Lead investigator on the study, Linda A. Feagins, MD, assistant professor of medicine at UT Southwestern Medical Center, speaking at a DDW press conference, noted that the study was limited in that it was retrospective and in that most of the polyps removed were small (<1 cm).

Press conference moderator Nicholas J. Talley, MD, PhD, University of Newcastle, Callaghan, Australia, said that the study had made him more convinced that continuing clopidogrel with removal of small polyps is the most sensible approach. He expressed apprehension, however, about removing larger polyps with clopidogrel discontinued, and said when colonoscopy revealed a large polyp, he would ask patients to return for a second procedure.

Feagins responded, “All procedures have complications. The risk is small, but when we have to treat PPB, we are good at it.” The largest polyp removed in the study was 8 mm. “We use hemoclips. That makes us feel better,” she said.