As we discuss the prophylactic value of hemostatic clips in colon polypectomy, it is important to begin by noting that there are some facts that are not up for “debate.” First, in the average-risk patient (i.e., no ongoing antiplatelet or anticoagulant agents), there is no data to support routine use of prophylactic clip closure after removal of polyps less than 20 mm in size. This is both due to the low baseline risk of post-polypectomy bleeding (PPB) and the costs associated with clipping. For this reason, recent studies have focused on use of hemostatic clips for larger defects, generally from polyps greater than 20 mm in size. Thus, the three high-quality randomized controlled trials on this topic published within the past year focus on the effectiveness of prophylactic clips specifically with regards to PPB risk after endoscopic resection of large colon polyps; two studies included only polyps greater than 20 mm,1,2 while a third included all polyps greater than 10 mm.3 Most polyps encountered in daily practice are less than 10 mm for which there is no data to support prophylactic clip closure.
Among the subgroup of “large” polyps, there is robust data arguing against prophylactic clip closure of any left-sided lesion. Although two of the three recent studies showed an overall benefit for prophylactic clip closure with regards to reducing PPB rates, one study demonstrated no reduction in bleeding risk for left-sided/distal colon polyps and the other study did not present compelling data to support use of endoscopic clips in the left colon (though it was underpowered for this subgroup analysis). Thus, until additional data is available, there is no clear role for endoscopic clip closure of polyps less than 20 mm or left-sided polyps of any size. The residual debate then, is whether clip closure effectively reduces PPB rates following endoscopic mucosal resection (EMR) of large right-sided colon polyps. It is in this narrow window where conflicting data must be resolved.
In fact, nothing highlights the challenges of successful endoscopic clip closure more than data from the Albeniz et al study wherein only 57% of large polypectomy defects randomized to clip closure were successfully completely closed — and this is in expert hands!
In their respective studies, Pohl et al and Albeniz et al both found that clip closure after EMR effectively reduced PPB for right-sided colon polyps greater than 20 mm with clinically relevant absolute risk reductions of 6.3% and 8.1%. Although this data is compelling, Feagins et al recently demonstrated no benefit in a similar subgroup with a numerically greater risk of bleeding in the clip closure group. So, how do we resolve this clearly contradictory data around the efficacy of endoscopic clip closure? As endoscopists, we often frame debates around endoscopic therapies — in this case, the debate around whether ‘endoscopic clips’ can reduce the risk of PPB — by eliminating the most critical components of the debate, the endoscopist themselves. Absent an endoscopist with experience in EMR and clip closure, a clip is an expensive piece of metal sitting on the shelf or, as we too often see, loosely attached to the colon wall distant from the polypectomy defect. Instead, when considering the prophylactic value of endoscopic clips, it is important to understand the outcomes achieved when endoscopic clips are used in routine practice by the typical endoscopist.
These studies highlight what we already know – endoscopists have variable training, experience and skill. In both the Pohl et al and Albeniz et al studies, the physician group was limited to endoscopists with expertise in EMR (based on EMR procedure volumes). In contrast, in the Feagins et al study, the explicit goal was to evaluate the use of the clips in the ‘real world’ setting. Thus, they enrolled all patients at the time of screening colonoscopy (not knowing whether a large polyp would be found) and included endoscopists with varying levels of expertise and experience with endoscopic clips. I hypothesize that it is this variation in technical skill that explains the seemingly contradictory data around prophylactic endoscopic clip closure after large right-sided colon polypectomy. The high level of skill required to adeptly place endoscopic clips is underrecognized. In fact, nothing highlights the challenges of successful endoscopic clip closure more than data from the Albeniz et al study wherein only 57% of large polypectomy defects randomized to clip closure were successfully completely closed — and this is in expert hands!
In summary, endoscopic clips are another example of the classic efficacy vs effectiveness debate. The available data suggests that in hands of an endoscopist with expertise in complex resection, endoscopic clip closure likely reduces the risk of PPB in the right colon after removal of large (>20 mm) non-pedunculated polyps. Outside of this narrow subgroup, we cannot confidently say that endoscopic clips are effective and, given the inherent procedural time and cost, may not be an appropriate use of limited health care dollars. While the endoscopic clips themselves are “effective,” we must similarly ensure that each endoscopist using clips is equally effective.
1. Pohl H., Grimm I.S., Moyer M.T., et al. Clip closure prevents bleeding after endoscopic resection of large colon polyps in a randomized trial. Gastroenterology. 2019;157(4):977-984 e
2. Albeniz E., Alvarez M.A., Espinos J.C., et al. Clip closure after resection of large colorectal lesions with substantial risk of bleeding. Gastroenterology. 2019; 157(5):1213-1221.e4
3. Feagins L.A., Smith A.D., Kim D., et al. Efficacy of prophylactic hemoclips in prevention of delayed post-polypectomy bleeding in patients with large colonic polyps. Gastroenterology. 2019;157(4):967-976 e1.