Abstract 2248: Canine Model of Esophageal Injury and Left Atrial -Esophageal Fistula After Pulmonary Vein Ablation
The purpose was to develop a canine model of esophageal (Eso) injury and LA-Eso fistula after pulmonary vein (PV) ablation.
Methods: 20 dogs were studied using transeptal puncture. A forward firing high intensity focused ultrasound (US) balloon catheter (HIFU, ProRhythm, 13 dogs) was positioned with 20mm US ring close to Eso in LA (outside PV, n=6) or inside PV (n=7). A 15mm side-firing US balloon catheter (SFU, 7 dogs) was placed inside PV, close to Eso. A 25 mm air-filled balloon was placed in Eso (7 thermocouples, 2mm apart). Variable Eso balloon inflation controlled distance between US and Eso, pressing Eso against US balloon (worst case for Eso injury). 1–9 (median 5) HIFU (35W) or 5 SFU (40W) were applied for 40 sec. Endoscopy was performed during, 2 wks and 4 wks after ablation. Dogs were sacrificed at 2 hrs (n=9) or 4 wks (n=11).
Results: Fig⇓. Highest Eso temp was localized to a very small area. Eso Ulcer was present when max Eso temp ≥50°C. For HIFU in LA (outside PV), Eso temp was ≥50°C only for HIFU within 2mm of Eso balloon. For HIFU or SFU inside PV, Eso temp was ≥50°C with US delivered up to 6.8mm from Eso. Eso ulcer occurred in 18/20 dogs. During follow-up in 11 dogs with acute ulcer, endoscopy at 2 wks showed ulcer healing (no esophagitis) in 6/11 dogs. 5/11 dogs had ulcer progression, all with esophagitis and relaxed lower Eso sphincter. 2/5 dogs (both SFU in PV) with ulcer progression died at 2 wks with LA-Eso fistula.
Conclusions: This model found higher Eso temp with US inside PV. Eso ulcer (transmural necrosis) occurred when Eso temp ≥50°C. Ulcer progression and LA-Eso fistula were associated with esophagitis and relaxed lower Eso sphincter, suggesting ulcer progression occurs with gastric reflux.