Interventional atrial septal defect closure using a totally bioresorbable occluder matrix: development and preclinical evaluation of the BioSTAR device.
OBJECTIVE
We sought to test the hypothesis that interventional atrial septal defect (ASD) closure can be performed safely and effectively using a bioresorbable occluder matrix.


BACKGROUND
The ideal septal occluder scaffold should promote the healthiest and most complete healing response while eventually facilitating the full resorption of the material and leaving "native" tissue behind, thus minimizing the potential for future complications from chronic foreign body and maintaining the possibility for later unobstructed transseptal access to the left atrium.


METHODS
The STARFlex occluders (NMT Medical Inc., Boston, Massachusetts) were modified by substituting the conventional polyester fabric for a bioengineered, acellular type-I collagen matrix derived from porcine submucosa with a heparin-coated surface (BioSTAR occluder, NMT Medical Inc.). Comparative transcatheter closure of ASDs was performed in young sheep (n = 36). Gross pathology and histopathology were obtained after follow-up periods ranging from 7 days to 2 years.


RESULTS
The STARFlex (control) devices were encapsulated time-dependently by ingrown fibrous tissue. Histology showed a mild but chronically persisting foreign body reaction. By contrast, BioSTAR devices exhibited a mild-to-moderate transient cellular immune response. Heparin coating of the BioSTAR surface improved the biocompatibility of the device by reducing surface thrombogencity. A remodeling process of the collagen scaffold, starting after 30 days in vivo, resulted in the full replacement of the matrix by host tissue after 2 years of follow-up.


CONCLUSIONS
The BioSTAR device is the first septal occluder with a totally bioresorbable matrix that is fully replaced by host tissue during the healing process. The promising results of this study support testing of the BioSTAR device in clinical trials.
Jux
Christian
C
Department of Pediatric Cardiology, Georg-August University, Goettingen, Germany. Dr.C.Jux@medizin.uni-goettingen.de
Bertram
Harald
H
Wohlsein
Peter
P
Bruegmann
Michael
M
Paul
Thomas
T
D020341:Absorbable Implants; D000818:Animals; D006328:Cardiac Catheterization; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000628:therapy*; D006493:Heparin; D019736:Prostheses and Implants; D012756:Sheep; D023822:Tissue Engineering
D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D006493:Heparin