From the AGA Journals

Electrosurgical choices lead to similar results

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Yellow equals blue

There has long been a debate over which type of electrosurgical setting is best for colon polyp resection. Endoscopists can use either a blended current (yellow pedal) or a coagulation current (blue pedal). The choice is based on the endoscopists’ preference. However, few data have been available to support one setting versus the other. This study by Pohl et al. pursued the burning question of yellow or blue pedal? This single-blind randomized multicenter trial compared the two commonly used electrosurgical settings (Blended Current/Endocut Q vs. Forced Coagulation) for the resection of large colorectal polyps and found no difference in the risk of serious adverse events, complete resection rate, or polyp recurrence, thus supporting the current practice that electrosurgical settings can be selected based on endoscopist expertise and preference.

A few important highlights from this well designed study are worth mentioning. Although there was no significant difference in perforation, it should be noted that fewer patients had a perforation event in the Forced Coagulation group than in the Endocut Q group (3 vs. 6 patients; P = .320). In addition, the study demonstrated that the rate of polyp recurrence did not differ significantly between the two groups (17.4% vs. 16.5%; P = .762). while the rate of macroscopically visible recurrence was not statistically different, a histologic recurrence without visible polyp tissue was found slightly less frequent in the Forced Coagulation group than in the Endocut Q group (3.1% vs. 6.0%; P = .07). Finally, another important observation, intraprocedural bleeding requiring treatment, occurred less frequently during resection with Forced Coagulation than with Endocut Q (11% vs. 17%, P = .006); however, this difference did not affect overall safety and efficacy. This is an important finding since bleeding can affect the field of view during polypectomy, which that can potentially increase the risk of other serious adverse events such as perforation or increase the risk of recurrence because the endoscopist may not completely resect the polyp.

This study provides important insights into the potential risks associated with blended vs. coagulation currents. It further shows there is no difference in safety and efficacy of polypectomy using either a blended current or coagulation current, thus supporting current practice. However, the authors make it clear that a larger study will be needed to better answer such questions as polyp recurrence and perforation more definitively.

Frank G. Gress, MD, MBA, is senior faculty at the Icahn School of Medicine at Mount Sinai, New York; chief, division of gastroenterology and hepatology, and director of the Center for Interventional Endoscopy at Mount Sinai Hospital South Nassau. He has no conflicts.



For endoscopists performing electrosurgical snare resection of large colorectal polyps, choosing between the blue foot pedal and the yellow foot pedal may be the least important step of the day, according to data from almost 1,000 patients.

Risks of severe adverse events and polyp recurrence were similar between cases in which blended current (yellow pedal) was used and those in which coagulation current (blue pedal) was used, reported lead author Heiko Pohl, MD, of Geisel School of Medicine at Dartmouth, Hanover, N.H., and colleagues.

“Although electrosurgical application is a fundamental aspect of polypectomy, various currents and settings are clinically used, and there are no accepted standards of practice,” the investigators wrote in Gastroenterology.

According to Dr. Pohl and colleagues, a 2004 study showed that the split between endoscopists using coagulation current and those using blended current was about 50-50 (46% vs. 46%), but no studies to date have tested the relative safety or efficacy of these approaches.

The investigators aimed to address this knowledge gap with a single-blinded study involving 928 patients who underwent endoscopic mucosal resection of nonpedunculated, large (20 mm or larger) colorectal polyps with an Erbe Vio® 300D electrosurgical unit (Erbe USA Inc., Marietta, Ga.) at 18 medical centers.

Patients were randomized in 2x2 factorial design involving clip closure versus no clip closure, and blended current (Endocut Q) versus pure coagulation current (Forced Coagulation). Although electrosurgical setting was initially a secondary intervention in the trial, post hoc analysis showed that interaction between the interventions was not significant (P = .957), allowing for the present, independent analysis of current type.

For this analysis, the primary outcome was severe adverse event rate, both during the procedure, and after the procedure for up to 30 days. Secondary outcomes included proportion of polyps completely excised and recurrence rate at time of first surveillance endoscopy.

Out of 928 patients randomized, 919 completed 30-day follow-up, and 675 underwent first surveillance colonoscopy. Baseline characteristics were similar between groups, apart from the proportion of individuals with more than one large polyp, which was significantly greater in the Endocut Q group (8.6% vs. 4.5%; P = .012), although the investigators noted that this imbalance did not affect main outcomes.

Rates of severe adverse events were similar between groups: 7.2% for the Endocut Q group and 7.9% for the Forced Coagulation group (P = .762). Groups also had similar rates of intra- and postprocedure adverse events, and types of adverse events.

Efficacy measures also revealed high similarity between cutting techniques. Endoscopists using Endocut achieved complete polyp removal 96% of the time, compared with 95% of the time when using Forced Coagulation (P = .267). Piecemeal resection rates were similar, at 90% and 87% for Endocut Q and Forced Coagulation, respectively (P = .270).

Although Endocut Q less frequently resulted in small residual tissue islands after initial snare resection (35% vs. 41%; P = .041), it more often caused intraprocedural bleeding that required treatment (17% vs. 11%; P = .006).

According to Dr. Pohl and colleagues, previous discussions have included concerns that such bleeding may impair visualization and therefore lead to higher rates of polyp recurrence; but surveillance colonoscopy, which was performed in 79% of patients, revealed a polyp recurrence rate of 17% for each group.

“Although we did not find a difference in recurrence between the two groups, our study cannot completely exclude this possibility,” the investigators added.

They also noted that six perforations occurred in the Endocut Q group, compared with three in the Forced Coagulation group, and suggested that this risk may be real, yet statistically unsupported by the present analysis because of sample size.

“Endoscopists using Endocut should therefore be aware of this potential risk and [ensure] that no muscularis propria is entrapped in the snare before electrosurgery is applied,” the investigators wrote.

Still, the investigators’ final conclusion supported the existing method of decision-making: personal choice.

“Overall, polyp resection with Endocut or Forced Coagulation did not differ with respect to severe adverse events, complete resection rate, or polyp recurrence,” they wrote. “This study therefore supports an individual approach based on endoscopist preference.”

The study was funded by Boston Scientific and the American College of Gastroenterology. The investigators disclosed additional relationships with Medtronic, Olympus, Cook Endoscopy, and others.

SOURCE: Pohl H et al. Gastroenterology. 2020 Mar 12. doi: 10.1053/j.gastro.2020.03.014.

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