Ingrowth of aorta wall into stent grafts impregnated with basic fibroblast growth factor: a porcine in vivo study of blood vessel prosthesis healing.
OBJECTIVE
Endovascular aneurysm repair is an alternative treatment of abdominal aortic aneurysm. The procedure is less invasive, and morbidity and most probably mortality are reduced. However, some problems, such as endoleakage, are yet to be resolved. Endoleakage can occur after graft migration, as a result of insufficient fixation of the stent graft. One cause is deficient healing between the aortic neck and the stent graft. We hypothesize that better healing, achieved by induction of vascular cell ingrowth into the graft material, results in better graft fixation. Previously we demonstrated ingrowth of neointima into the graft material if the stent graft is impregnated with a coat of basic fibroblast growth factor (bFGF), heparin, and collagen. In this study we evaluated healing with bFGF-heparin-collagen-coated stent grafts in vivo.


METHODS
In 4 pigs, 32 endovascular stent grafts, manufactured from standard Dacron and Gianturco Z-stents, were placed in the aorta. The stent grafts were impregnated with either bFGF-heparin containing collagen (n=16) or control collagen (n=16). After 4 and 8 weeks animals were killed, and ingrowth and healing of the stent grafts were macroscopically and electron microscopically evaluated.


RESULTS
After 8 weeks all bFGF-impregnated stent grafts demonstrated ingrowth of tissue and healing between the graft and the aorta, whereas the control nonimpregnated stent grafts showed no ingrowth. Microscopic evaluation demonstrated alpha-smooth muscle actin-positive cells, most probably smooth muscle cells or myofibroblasts, growing from the vascular wall through the graft material.


CONCLUSIONS
A Dacron prosthesis impregnated with collagen, heparin, and bFGF induced graft healing in an in vivo pig model, in contrast to nonimpregnated stent grafts. This in vivo study confirms our previous findings in vitro. These results indicate that healing between Dacron and the aorta can be achieved, and suggest that type I endoleakage may be resolved by inducing healing between the aortic wall and the prosthesis with graft material containing growth factor.
van der Bas
J M Annemieke
JM
Gaubius Laboratory TNO-PG, Leiden University Medical Center, The Netherlands.
Quax
Paul H A
PH
van den Berg
Arjen C
AC
Visser
Michel J T
MJ
van der Linden
Edwin
E
van Bockel
J Hajo
JH
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology*; D006493:Heparin / Q000494:pharmacology; D008853:Microscopy; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects; D023421:Models, Animal; D032390:Myoblasts, Smooth Muscle / Q000187:drug effects* / Q000502:physiology; D011093:Polyethylene Terephthalates / Q000494:pharmacology / Q000627:therapeutic use; D011475:Prosthesis Failure; D015607:Stents; D013552:Swine; D014945:Wound Healing / Q000187:drug effects*
D020099:Coated Materials, Biocompatible; D006133:Growth Substances; D011093:Polyethylene Terephthalates; D016222:Fibroblast Growth Factor 2; D006493:Heparin; D003094:Collagen