Evaluation of a novel cryoballoon swipe ablation system in bench, porcine, and human esophagus models.

Current ablation devices for dysplastic Barrett's esophagus are effective but have significant limitations. This pilot study aims to evaluate the safety, feasibility, and dose response of a novel cryoballoon swipe ablation system (CbSAS) in three experimental in vitro and in vivo models. CbSAS is a through-the-scope compliant balloon that is simultaneously inflated and cooled by liquid nitrous oxide delivered from a disposable handheld unit. When the cryogen is applied through a special diffuser it covers a 90° section of the circumference of the esophagus for 3 cm length. Doses range from 0.9 to 0.5 mm/second. (1) Bench model: The fixture consisted of an 'esophagus-like' tube lined with agar at 37°C to create an inner diameter of 20 or 30 mm, within which thermocouples were embedded. (2) In vivo porcine esophagus: CbSAS ablations were performed in animals that were euthanized and histological assessments of depth and percentage of esophageal mucosa successfully ablated were done. (3) In vivo, pre-esophagectomy human esophagus. After CbSAS ablations, histological assessments were performed (at 0, 4, and 28 days) to assess the depth and percentage of ablated mucosa. As outcomes, we assessed the safety and tolerability (pain and serious, device-related adverse events); efficacy (depth and uniformity) of ablation; and device performance (ease of deployment and device malfunction). In the bench model, during CbSAS, thermocouples measured minimal temperatures of -40 to -48 °C at all doses. In the porcine model, maximal effect on the mucosa was reached with a dose of 0.8 mm/second that extended to superficial submucosa, while 0.5 mm/second extended through the submucosa. All animals tolerated the treatments and, regardless of ablation dose, continued oral intake and gained weight. In the human model, six patients (5 male, 1 female, mean age 68) tolerated the procedure without adverse events. CbSAS was simple to operate, and balloon contact with tissue was easily and uniformly maintained. The maximal effect on the mucosa is achieved with a 0.8 mm/second dose. We concluded that the CbSAS device enables uniform 3 cm long, quarter-circumferential mucosal ablation in a one-step process by using a novel, through-the-scope balloon. The CbSAS delivers predictable ablation with mucosal and limited submucosal necrosis in bench, animal, and human esophagus. Because of its ease of use, this new device merits further clinical study in the treatment of patients with dysplastic Barrett's esophagus.