Westanmo, Anders

Abstract Introduction Underwater endoscopic mucosal resection (uEMR) technique has gained popularity for removal of large non-pedunculated colorectal polyps (LNPCPs) due to high en-bloc resection rates and lower recurrence rates. However, there is no information regarding outcomes of uEMR for giant colorectal polyps. Therefore, we aimed to evaluate the outcomes of uEMR for giant colorectal polyps across multiple centers in North America. Methods We conducted a multicenter retrospective study of adults with giant colorectal polyps undergoing uEMR between January 2019 and November 2025. Giant colorectal polyps were defined as LNPCPs ≥40 mm. Primary outcomes were technical success and rate of recurrent adenoma. Secondary outcomes were severe adverse events (SAEs) and predictors of technical success, recurrence, and SAEs. Results A total of 137 polyps, with mean polyp size 47.6 mm were included. Majority of the lesions were located in right colon (61%, n = 83) with the most common histopathology being high-grade dysplasia (HGD) (31.4%, n = 43). Technical success was achieved in 90.5% (n = 124) with en-bloc resection rate of 11.7% (n = 16). Polyp fibrosis (OR: 0.08) and HGD (OR: 0.15) were independent predictors of inability to achieve technical success. Of 92 (67.1%) patients with follow-up, recurrent polyp was present in 8.7% (n = 8). SAEs were noted in 9.5%, consisting of delayed bleeding (9.5%, n = 13), while no delayed perforation or post polypectomy syndrome was noted. Discussion Our study demonstrates that uEMR is technically feasible for the removal of giant colorectal polyps with an acceptable safety profile and recurrence rate.

Abstract Purpose We previously reported an interaction with warfarin anticoagulation when initiating treatment with direct-acting antiviral agents for hepatitis C infection. A decreased warfarin sensitivity led to subtherapeutic anticoagulation. To study this interaction further, we expanded our research to include patients treated with the combination of elbasvir and grazoprevir concurrent with warfarin anticoagulation and investigated changes in warfarin sensitivity during and after treatment. Methods Using electronic health records of the Veterans Health Administration, patients starting treatment with elbasvir–grazoprevir for hepatitis C infection concurrent with warfarin anticoagulation were identified. Inclusion required stable warfarin anticoagulation prior to 12 weeks of treatment with elbasvir–grazoprevir. A warfarin sensitivity index (WSI) was calculated at the start and end of treatment and 12 weeks after treatment. The primary endpoint was the difference in WSI from pre- to end-treatment. The secondary endpoint was the WSI difference from pretreatment to 12 weeks posttreatment. Changes in International Normalized Ratio, warfarin doses, and time in therapeutic range were measured. Results In the final sample of 43 patients, the mean WSI decreased during treatment from 0.53 to 0.40, or 25.2%. After treatment, the mean WSI rose to 0.51. Although the mean weekly warfarin dose increased from 40.3 to 44.6 mg during treatment, the mean International Normalized Ratio decreased from 2.40 to 1.96, recovering to 2.59 after treatment. The time spent in therapeutic range decreased from 74.1% before treatment to 39.8% during treatment and back to 64.9% 12 weeks posttreatment. Conclusion When elbasvir–grazoprevir was added to stable warfarin anticoagulation, warfarin sensitivity decreased significantly during treatment and returned to baseline after treatment.