Development and preclinical evaluation of a biodegradable ventricular septal defect occluder.
OBJECTIVE
This study evaluated the feasibility, effectiveness, and safety of a biodegradable (BD) occluder for closure of ventricular septal defect (VSD) in an acute canine model.


BACKGROUND
All current available VSD occluders are permanent implants which consist of a metal framework and synthetic fabrics. However, the septal occluder in vivo plays the role of a temporary bridge that facilitates the ingrowth of fibrous connective tissue and endothelialization. The ideal occluder may be a temporary scaffold which can be gradually absorbed in vivo and replaced by "native" tissue.


METHODS
The BD VSD occluder consists of a polydioxanone (PDO) framework and two pieces of poly-L-lactic acid (PLLA) fabrics. Percutaneous transcatheter closure of interventionally created VSDs was performed in 16 dogs using the BD occluders. Follow-up consisted of electrocardiography, transthoracic echocardiography, and fluoroscopy from 1 week to 24 weeks post-implantation. Gross pathology and histopathology were obtained at 6, 12, and 24 weeks follow-up.


RESULTS
Implantation of the BD occluders was successful in 15 animals. The devices became well integrated into the ventricular septum with complete endothelialization at 12 weeks after implantation. After 24 weeks in vivo, the PDO framework of devices was largely absorbed and replaced by the ingrowth of collagenous fibers, and the PLLA fabric within disks was partly degraded. Neither occluder dislocation nor VSD recanalization occurred during follow-up.


CONCLUSIONS
The BD occluder proved safe and effective for VSD closure. This device is characterized by compatible mechanical properties, a fully BD property, and a good match between the degradation of occluder and the healing response of organism.
Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai, China.
Xin-miao
XM
Huang
Yu-feng
YF
Zhu
Jiang
J
Cao
Jian-qiang
JQ
Hu
Yuan
Y
Bai
Hai-bing
HB
Jiang
Zhao-feng
ZF
Li
Ying
Y
Chen
Wei
W
Wang
Yong-wen
YW
Qin
D020341:Absorbable Implants; D000818:Animals; D006328:Cardiac Catheterization / Q000295:instrumentation*; D004195:Disease Models, Animal; D004285:Dogs; D005240:Feasibility Studies; D024022:Fibrillar Collagens / Q000378:metabolism; D006345:Heart Septal Defects, Ventricular / Q000175:diagnosis / Q000628:therapy*; D019344:Lactic Acid; D008422:Materials Testing; D016687:Polydioxanone; D011091:Polyesters; D011108:Polymers; D011474:Prosthesis Design; D011859:Radiography; D055989:Septal Occluder Device; D013997:Time Factors; D014463:Ultrasonography; D054088:Ventricular Septum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology
D024022:Fibrillar Collagens; D011091:Polyesters; D011108:Polymers; D016687:Polydioxanone; D019344:Lactic Acid; C033616:poly(lactide)