Endoscopic Radiofrequency Ablation for Barrett’s Esophagus

Proprietary names: HALO90 System; HALO90 Ablation Catheter; HALO90 Coagulation Catheter; HALO90  Energy Generator; HALO90  Focal Ablation Device; HALO360 System; HALO360 Ablation Cather; HALO360 Energy Generator; HALO360 Filter; HALO360  Sizing Balloon; HALO CAP; HALO Guide Wire

Generic procedure names: balloon-based radiofrequency ablation; circumferential radiofrequency ablation; endoscopic radiofrequency ablation; focal radiofrequency ablation

Endoscopic radiofrequency ablation (RFA) is an outpatient endoscopic procedure intended to treat intestinal metaplasia (IM), low-grade dysplasia (LGD), and high-grade dysplasia (HGD) associated with Barrett's esophagus (BE). RFA uses controlled pulses of energy to burn the thin layers of BE tissue. This report focuses on the HALO360 and HALO90 systems (BÂRRX Medical, Inc., Sunnyvale, CA, USA), which are RFA systems that have specialized endoscopic catheters composed of electrode arrays to deliver ablative energy to the targeted tissue. According to the product brochure for the HALO360 and HALO90 Systems and the manufacturer's Web site, RFA with HALO Systems:

The HALO360 System provides circumferential (360°) ablation of BE segments. It includes the following components:

For ablation of BE using the HALO360 System, a gastroenterologist or surgical endoscopist performs the procedure with the patient under conscious sedation. After inserting the endoscope to perform irrigation to remove mucus, the clinician measures the length of the BE segment and directs the system to measure the esophageal diameter in 1-cm increments by repeatedly inflating the sizing balloon. Based on these measurements, the clinician chooses the appropriate size ablation catheter. The physician removes the sizing balloon and introduces the catheter, which is encircled by the electrode array. When the ablation catheter is positioned on the targeted area, the physician activates the generator to inflate the balloon and deliver a standardized energy dose to the tissue. The generator automatically deflates and repositions the balloon for the next segment of the treatment area. The clinician overlaps treatment zones to ensure coverage of the entire BE zone. If the clinician ablates the BE zone a second time, any coagulated tissue from the catheter and electrode is removed before proceeding. (Pouw et al. 2008; Sharma and Fleischer 2007).

The HALO90 System provides primary focal ablation energy to smaller BE segments than the HALO360 System—segments that are < 2 cm in length. It is also used for secondary treatment after primary ablation with the HALO360 System or another therapeutic device. The HALO90 consists of a radiofrequency generator and an endoscope-mounted ablation catheter with a radiofrequency electrode on an articulating platform. For primary ablation, the physician mounts the catheter onto the endoscope in an unarticulated position and then irrigates the esophagus and introduces catheter and endoscope while articulating the electrode to lie flat against the BE segment. The system automates delivery of ablative energy twice in rapid succession. After cleaning the ablated areas and the electrode surface of any coagulated tissue, the clinician reintroduces the catheter and treats the BE zone again, repeating this sequence until a total of 4 energy applications have been delivered (Pouw et al. 2008; Sharma and Fleischer 2007). A second circumferential ablation session may be performed, as needed, several weeks...