A newly-designed temporary cardia stent for the treatment of achalasia:an experimental study in canine models / 介入放射学杂志

ABSTRACT

Objective To assess the efficacy and safety of a newly-designed temporary covered cardia stent for the treatment of achalasia in canine models and to investigate the histopathological changes at different points of follow-up time after the stent was removed. Methods The canine achalasia model was created by injecting benzyl-dimethyl-tetradecyl ammonium chloride (BAC) circumferentially into the lower esophageal sphincter (LES) of the dogs. Twenty-four dogs with achalasia were randomly and equally divided into two groups with 12 dogs in each groupcontrol group (using routine esophageal stents) and study group (using newly-designed temporary covered cardia stents). Under fluoroscopic guidance stents were implanted in the esophagus and were taken away from the esophagus 4 days after stent insertion in experimental dogs of both groups. LES pressures and timed barium esophagography (TBE) were performed in all dogs before and immediately after the stenting procedure,as well as at one week,3 and 6 months after the stent was removed. Every three dogs were sacrificed each time at one week,3 and 6 months after the stent was removed. The esophageal cardia was excised and sent for pathological examination. Results All animals well tolerated the stent insertion / removal and the follow-up procedures. No severe complications such as esophageal perforation occurred. Comparison between two groups showed that stent migration occurrence was much lower in study group (n = 1) than that in control group (n = 5). The reduction of LES pressures in study group was more significant in comparison with control group (at 6-month follow-up,P = 0.027). The difference in barium column product (height ? width) between 0-min and 5-min TBE was statistically significant in study group (at 3-month follow-up,P = 0.009). Integrated analysis of multi-comparison for LES pressures among subgroups of each group revealed that the dogs in study group exhibited better outcomes than the dogs in control group. Both proliferating cell nuclear antigen (PCNA) and ?-smooth muscle actin (?-SMA) immuno-staining revealed that the inflammatory reaction reached its peak at 1-month follow-up. Trichrome staining indicated that the collagenous fiber proliferating index inclined to be stable at 3-month follow-up. Conclusion In treating achalasia in canine models the newly-designed temporary covered cardia stent is superior to the routine esophageal stent in respect of safety and efficacy.