A randomized trial comparing effects of radiofrequency and cryoablation on the structural integrity of esophageal tissue

Background Esophageal injury is a rare, but catastrophic complication of radiofrequency (RF) pulmonary vein isolation. It is not known if cryoablation is less likely to injure esophageal tissue. The purpose of this study is to compare the effects of RF and cryoablation on the structural integrity of esophageal tissue. Methods and results Porcine esophageal tissue was sectioned into 396 strips measuring 3 mm in width by 30 mm in length. Samples were randomly assigned to receive no ablation (149 specimens in the control group), RF ablation (126 specimens) or cryoablation (121 specimens). A single ablation was administered in the center of the tissue sample. A force gauge was used to measure the tensile strength of the tissue sample in Newtons. Groups were compared using ANOVA and a Bonferroni post-test. The mean tensile strength in the control group was 2.19 N (SD, 2.17), 1.66 N (SD, 0.88) for RF ablated tissue and 1.96 N (SD, 1.68) for cryo. RF ablation resulted in a significant reduction in esophageal tensile strength when compared to control (t=2.59), however cryo did not (t=1.11). On microscopic evaluation RF ablation disrupted elastic fiber architecture whereas cryoablation did not. Conclusions Cryoablation has no significant adverse impact on the structural integrity of esophageal tissue. Cryoablation may be a safer alternative to RF for left atrial ablation and reduce the risk of esophageal injury and atrial-esophageal fistula formation.