Basic fibroblast growth factor slow release stent graft for endovascular aortic aneurysm repair: A canine model experiment

ObjectivePersistent endoleak and endotension, complications after endovascular aortic repair, may be caused by an unorganized thrombus inside the aneurysm. The experimental study was designed to evaluate the effectiveness of stent grafts (S/Gs) with slow release of basic fibroblast growth factor (bFGF) for the organization.MethodsThe S/Gs were constructed of self-expanding Z stent covered with expanded polytetra fluoroethylene graft, and coated with elastin to be able to bind and slowly release bFGF. Five elastin-coated S/Gs with bFGF (bFGF-S/Gs) and without bFGF (C-S/Gs) were placed in the normal canine aorta respectively. The thoracic aortic aneurysm models were surgically created with a jugular vein patch in 12 beagles. S/Gs with six holes, for creating endoleaks, were used in the experiment of aneurysmal repair. The bFGF-S/Gs (n = 6) and C-S/Gs (n = 6) were implanted. The beagles were sacrificed at two weeks after the endovascular procedure and examined histologically.ResultsThe bFGF-S/Gs induced six times the intimal proliferation of the C-S/Gs in normal aorta. Twelve animals had successfully created aneurysms, and had endoleaks just after the endovascular procedure. At two weeks after the endovascular procedure, the percentage of fibrous area in the aneurysmal cavity treated with bFGF-S/G (35.7 ± 4.3%) was significantly greater than C-S/G (13.6 ± 2.2%) (P < .01).ConclusionbFGF-S/Gs are effective for accelerating organization of the aneurysm cavity and developing neointima. Further research on bFGF-S/Gs would clarify the association of endoleaks.

Clinical RelevanceEndovascular stent graft placements are widespread as a safe and less invasive procedure with acceptable clinical results. However, a persistent endoleak, which is blood-flow leak in the excluded cavity, or endotension, which is pressure overload in the excluded cavity, inhibits organization and causes re-expansion of the aneurysm in some cases. The cause of this complication is thought to be unorganized thrombus occupying the intra-aneurysmal cavity. In this study, we examined the efficiency of stent-grafts with basic fibroblast growth factor delivery system in the canine thoracic aortic aneurysm model with endoleaks. We found that this method can accelerate thrombus organization of the aneurysmal cavity excluded by endovascular stent-grafts in spite of endoleaks. According to our basic results, stent-grafts with a drug delivery system may be applied to endovascular treatments of aneurysms and may improve results of the endovascular treatments.