Vessel Coagulation in Third Space Endoscopy: a Randomized Controlled Trial

Background: Third-space endoscopy is the standard of care for neoplastic and motility disorders; however, it is technically challenging because of the high risk of intraprocedural bleeding. Such a risk may be reduced by prophylactic coagulation of the submucosal vessels, but it requires instrument exchange. A new approach involves pre-sealing the submucosal vessels using standard electrocautery settings under brief saline immersion using the same knife. Methods: Patients undergoing third space procedures (ESD or POEM) were randomized to receive either targeted saline-immersion pre-sealing (study group) or conventional coagulation (CO2 insufflation, control group) for prophylactic management of vessels ≥1.2 mm. Dissection settings were identical (HybridKnife, SWIFT COAG mode). Rate of at per-patient intraprocedural bleeding requiring retreatment for vessels ≥1.2 mm was the main outcome. Per-vessel analyses were also performed. The use of an adjunctive device and coagulation time were also assessed. Results: Seventy patients (37 immersion, 33 control) with 864 ≥1.2 mm vessels were included. Saline-immersion pre-sealing significantly reduced bleeding rates both at per patient (32.4% vs 75.8%, RR 0.43, 95% CI 0.26-0.71; NNT 2.3; p=0.01) and at per vessel analysis (6.3% vs 29.9%, RR 0.21; 95% CI 0.14-0.31; NNT 4.2; p<0.01). The use of coagulation forceps for bleeding treatment also decreased (0% vs 24.2% and 0% vs 8.3%;p<0.01). A significant reduction in coagulation time was reported in the saline-immersion group (22.7±26.4 seconds vs 29.6±49.8 seconds;p<0.01). Conclusions: A substantial reduction in the risk of intraprocedural bleeding was achieved by saline-immersion pre-sealing in per-patient and per-vessel analyses, prompting its implementation in clinical practice.

Publication History

Received: 03 July 2025

Accepted after revision: 31 December 2025

Accepted Manuscript online:
05 January 2026