Abstract
Vascular prostheses implanted in growing children may cause serious hemodynamic disturbance, when they become too small in diameter comparing to the grown native arteries. We have developed vascular prostheses which can be dilated by a percutaneous trans luminal angioplasty (PTA) at a given time to compensate such discrepancy in diameter. The prosthesis was made of woven polyester fiber fabrics, the circumferential yarns of which consist of two different types of polyester fiber bundles. We have reported that the prostheses were successfully dilated with the use of PTA balloon in vitro and in the short term animal experiment as well. In this study, the prostheses with the initial diameter of 6 mm were implanted to descending thoracic aortae (8-10mm in diameter) of mongrel dogs for 18 months as a longer term evaluation. After 18 month-implantation, luminal surface of the prosthesis was completely covered with smooth neointima with little thrombus. With the use of PTA ballooning of 15 ATM, implanted grafts were dilated to 9 mm in diameter which was maintained after 30 days. No bleeding, hematoma or pseudo-aneurysmal formation were observed. 30 days after dilatation procedure, luminal surface of the graft was covered with neointima consisting of regularly oriented cell layers. In conclusion, the newly developed grafts could be safely dilated after implantation in vivo. The prostheses, when applied for the arterial reconstruction of growing children, may let us adjust the hemodynamic disturbances due to the size discrepancy and avoid re-implantation of the larger diameter grafts.
