Expandable prosthesis for sutureless anastomosis in thoracic aorta prosthetic substitution.

Abstract

Most complications of descending aorta prosthetic substitution seem mainly to be related directly (ischemia to distal organs, i.e. liver, kidney, spinal cord) or indirectly (extracorporeal circulation or shunts and systemic heparinization complications) to the duration of blood flow interruption. the purpose of this study is to report the results of animal experimentation of a new device for sutureless prosthetic substitution of the descending thoracic aorta, with a very short cross-clamping phase. The device consists of expandable loops of stainless steel wires, sewn to the proximal end of a Dacron prosthesis. The stainless steel wire loops can be expanded and tightened by activating a removable guide in such a way that the prosthesis varies its diameter, while maintaining a regular cylindrical shape. The device was prepared in two different configurations, one for long segments (expandable prosthesis end) and the other to be used for very short segments or as an anastomotic ring between prosthetic or vascular stumps (quick anastomotic ring). The expandable prosthesis end was tested in swine experiments by performing the prosthetic substitution of the first 10 cm of descending cross-clamped aorta, the prosthesis being fixed with the device both at the proximal and the distal ends (six experiments). All animals survived the procedure, that was accomplished with a very short cross-clamping time. The quick anastomotic ring was used to anastomose two prosthesis ends, at the middle of the prosthetic segment used for descending aorta substitution (two swine), to perform the distal anastomosis in the same model of descending aorta substitution (one swine) and simply to re-anastomose a subtotally transected descending aorta (one swine). The present experience proved the reliability of the device to carry out a sutureless, accurate, simple and quick anastomosis. Its advantage over an intraluminal ringed prosthesis is much easier insertion of the retracted wired end into the vascular stumps, thus allowing for a prosthetic diameter appropriate to the substituted vessel. The reduced cross-clamping feature of the device would suggest its use mainly in thoracic aorta prosthetic substitution for the prevention of ischemic damage to distal organs; it can also be used to advantage wherever an end-to-end vascular or prosthetic anastomosis is indicated, providing an accurate, stented anastomosis.