Efficacy of drug-coated balloon dilatation catheter in an animal model of acute Eustachian tube inflammation

ZHAO Jiajia; XIN Xiangmei; FENG Meiyan; WANG Xiaojun; LIU Xinli; WANG Yu; XIAO Xiuxiu; LIU Huifeng; ZENG Qilai; ZHOU Mi; ZHANG Ying

doi:10.3969/j.issn.1672-2922.2026.03.015

Abstract：Objective To report the efficacy of degradable microsphere particle drug-coated balloon dilation catheters in a model of acute eustachian tube inflammation,and its mechanisms of action on morphology,function and histopathological outcomes of the eustachian tube.Methods A randomized controlled experimental design was used.Nine(18 ears)miniature Bama pigs were randomly selected the controls(n=1,2 ears),acute inflammation model(n=1,2 ears),model control(n=1,2 ears),and self-controlled study group(n=6,12 ears),which received dilation with a sirolimus-dexamethasone composite drug-loaded balloon catheter,controlled with routine non-coated balloon dilation.An was established before the operation.eustachian tube balloon dilation surgery was performed 1 week after establishment of acute eustachian tube inflammation model.Otoscopy and eustachian tube endoscopy were completed before and after the operation for morphological changes.Histopathological study and lumen morphological measurement were conducted 4 weeks after the operation.Results The cartilaginous wall of the normal eustachian tube in Bama pigs was covered mainly by pseudostratified low-ciliated epithelium.In the acute eustachian tube inflammation model,the tympanic membrane showed acute hyperemia,with edema of the eustachian tube mucosa lining and partial transformation of the epithelium into pseudostratified ciliated columnar epithelium.The score of inflammatory cell infiltration was 2.96±0.464,significantly higher compared with the normal group(P＜0.001).After balloon dilation,the cartilaginous part of the Eustachian tube in the study group was covered mainly by pseudostratified low-ciliated epithelium with reduced inflammatory infiltration compared to the control and the model groups(P＜0.001).The inner diameter of the eustachian tube lumen in the study group showed a significant dilation effect at(162 174.8±100 526.46)μm2,(397.7%greater than that in the disease model group(P＜0.001)and significantly better than that in routine dilation control by 32289.81μm2(P=0.044).Conclusions Dilation with degradable microsphere particle drug-coated balloon exerts anti-inflammatory(dexamethasone)and anti-proliferative(sirolimus)effects in addition to mechanical dilation through sustained drug release,and effectively improves the eustachian tube microenvironment to maintain the morphological stability of the lumen.This is of great significance in improving the success rate of eustachian tube balloon dilation and in reducing the rate of recurrence.The results of this study demonstrate important application potentials in the clinical treatment of eustachian tube dysfunction.