A subanalysis of anticoagulant types reveals that, despite no overall benefit for prophylactic polypectomy clipping, there are differences by subgroup: There was a significantly lower bleeding in patients on direct oral anticoagulants (DOACs) and higher bleeding risk in patients on warfarin.
“In DOAC users, prophylactic clipping was associated with a 64% relative risk reduction in 30-day PPB [postpolypectomy bleeding],” versus no clipping, reported the authors of the study, published in.
The removal of colonic polyps is known to carry a high risk of hemorrhage, and the use of antithrombotic medications, including DOACs and warfarin, are well-established as key risk factors for the bleeding.
However, data on the effectiveness of prophylactic hemoclips in preventing PPB is inconsistent, with oneonly showing a benefit in colonic lesions that are larger than 20 mm and proximal to the hepatic flexure, and other studies .
To further investigate the effects among patients treated with anticoagulants, first author Louis H.S. Lau, MBChB, an assistant clinical professor in the department of medicine and therapeutics at the Chinese University of Hong Kong, and colleagues enrolled 547 patients with 1,485 polyps who underwent colonoscopic polypectomy while being treated with an oral anticoagulant between 2012 and 2020.
The percentages of warfarin and DOAC users were similar between the groups, at about 50% each.
Overall, PPB occurred in 30 out of the 285 patients (10.6%) who had clipping and 11 out of the 262 patients (4.2%) who did not have clipping. The mean polyp size among patients with PPB was about 8-9 mm, and the mean time to bleeding was between 7 and 9 days.
In the propensity-weighted analysis, there was no statistically significant difference in bleeding among those who did and did not receive clipping (odds ratio, 1.19; 95% confidence interval, 0.73-1.95; P = .497).
However, a subgroup per-patient analysis did show prophylactic clipping was associated with a significantly lower 30-day PPB risk among patients treated with DOACs (OR, 0.36; 95% CI, 0.16-0.82; P = .015), but a significantly higher bleeding risk in patients taking warfarin (OR, 2.98; P = .003), and in those with heparin bridging (OR, 1.69; P = .023).
The subanalysis showed no benefit of prophylactic clipping among the largest polyps, which differed in size across the subgroups (<10 mm vs. 10-20 mm vs. 20 mm).
Of note, the overall analysis showed a significantly higher risk of PPB with hot resection polypectomy using electrocautery (OR, 9.76; 95% CI, 3.94-32.60; P < .001), compared with cold biopsy or snare polypectomy.
The authors noted several limitations to their study, including the relatively high rate of bleeding overall (7.5%), which could be related to the more frequent use of hot snare in their cohort earlier in the study.
Effects caused by DOACs’ rapid onset?
In speculating on the reasons for the different risks observed between DOACs and warfarin, the authors suggested that “a possible explanation could be the rapid onset of action and steady pharmacokinetics of DOAC, reducing the necessity of heparin bridging in most cases.”
Meanwhile, the increased bleeding observed with warfarin despite clipping could be “related to the intrinsic properties of warfarin,” they added.
“Because of its slow onset of action, a larger proportion of patients will receive heparin bridging, which was previously reported to be a significant risk factor of PPB,” they noted. “Moreover, due to the substantial fluctuation in anticoagulation effect during warfarin titration, it may provoke delayed bleeding after the endoclips fall off subsequently.”
Unique focus on anticoagulant-treated patients
Senior author Raymond Shing-Yan Tang, MD, an assistant professor in the department of medicine and therapeutics, faculty of medicine, at the Chinese University of Hong Kong, noted that the study’s unique focus on patients treated with anticoagulants is important.
“Prior studies evaluating the effectiveness of prophylactic clipping in preventing postpolypectomy bleeding included a more heterogeneous patient population with both nonanticoagulated and anticoagulated patients,” Dr. Tang said in an interview.
“The strengths of our study were that it was a dedicated study that included only patients on oral anticoagulants, including warfarin and DOACs, and had a relatively larger sample size when compared to prior studies,” he said.
While most guidelines recommend prophylactic clipping in patients undergoing polypectomy for colonic lesions larger than 20 mm and proximal to the hepatic flexure, a variety of factors may ultimately guide decisions, Dr. Tang noted.
“In clinical practice, the decision to use prophylactic clipping after polypectomy in patients on anticoagulation is often individualized at the discretion of the endoscopist,” he said.
Anticoagulation question is important, but study has limitations
In commenting on the study, Heiko Pohl, MD, a professor of medicine at Geisel School of Medicine at Dartmouth, Hanover, N.H., noted that, while this study is important, it has some key limitations.
“The question the study raises is relevant – we really have no good idea whether this subset of patients that are anticoagulated should always be clipped,” he said in an interview.
However, he noted potential limitations in the methodology.
“It’s difficult to control for all important factors in a propensity trial,” he said, adding “there could be some unmeasured confounders that could not be accounted for due to the retrospective design.”
Nevertheless, Dr. Pohl agreed that the relatively rapid action of DOACs could help explain the effects.
“DOACs may have a high risk of bleeding sooner [than warfarin] to begin with, and therefore the clipping makes sense, so that may be the mechanistic idea,” he said. “But it’s difficult to generalize, because there have been no previous studies that have shown benefits from clipping for smaller polyps, even among patients on anticoagulants.”
The authors had no disclosures to report. Dr. Pohl has received grants from Steris and Cosmo Pharmaceuticals.