A novel biodegradable occluder for the closure of ventricular septal defects: immediate and medium-term results in a canine model.

Abstract

The feasibility of an Amplatzer septal occluder closure of ventricular septal defects (VSDs) under echocardiographic guidance has already been proven. However, the technique is not used routinely owing to high-rate atrioventricular blocks and the non-absorbability of the occluder. Here, we aimed to evaluate the safety, biocompatibility and effectiveness of a new biodegradable occluder. A total of 18 adult beagle dogs [mean body weight 8.85 kg (range 8.10-10.40 kg)] were enrolled in our study from March 2015 to July 2018. VSD animal models were prepared by thoracic intervention, and the new bioabsorbable occluder was implanted under the guidance of transthoracic echocardiography. Laboratory examinations, transthoracic echocardiography and electrocardiography were performed after surgery, and pathological samples from dogs were obtained after euthanasia and examined in the 1st, 3rd, 6th, 9th, 12th and 24th months to evaluate the safety, biocompatibility and effectiveness of the biodegradable occluder. All the dogs received successful implantations of the biodegradable occluder and survived, showing no follow-up-related complications (such as dislocation, arrhythmia and recanalization). Biochemical tests showed no significant abnormalities or differences, except for an increase in white blood cells and C-reactive proteins on the day after the operation. Histopathological examinations revealed that the bioabsorbable occluders were biocompatible, while immunohistochemical evaluations and electron microscopy showed endothelial cells growing on the occluder surface. The effective occlusion of VSD, good biocompatibility, rapid endothelialization and lack of complications shown by the biodegradable occluder in this study suggest that the device meets acceptable clinical safety and has potential application prospects.