Radiofrequency vapor ablation for Barrett's esophagus: feasibility, safety and proof of concept in a stepwise study with in vitro, animal, and the first in-human application.

ABSTRACT

INTRODUCTION: The Radiofrequency Vapor Ablation (RFVA) System (AquaMedical, Inc., Santa Ana, CA) is a novel ablation system for eradication of Barrett's esophagus, that generates vapor at 100 °C using an RF electrode located in the catheter tip. We performed in-vitro dosimetry studies and the first in-human feasibility study. METHODS: The system includes an RFVA generator with syringe pump and a through-the-scope-catheter. The RFVA system was tested in-vitro (lean-beef and porcine study) and ablation depth was compared to focal RFA. Two doses were selected for further in-vivo testing in dysplatic BE patients. Repeat endoscopy with histology was performed after 8 weeks to assess squamous conversion. RESULTS: In porcine, RFVA 3-seconds was comparable to RFA, whereas RFVA 5-seconds produced slightly deeper ablation. We selected a conservative 1-second and 3-seconds for human study. Fifty-three ablations were successfully applied in 15 patients with no adverse events. Follow-up endoscopy showed a median squamous conversion of 55 % (IQR 33 - 74) and 98 % (56 - 99) for 1 and 3-seconds, respectively. CONCLUSIONS: In this 3-phase study with lean-beef, porcine and the first in-human application, the RFVA system was feasible for esophageal ablation and successfully and safely converted targeted BE areas into squamous epithelium.