This investigation was designed to develop a satisfactory PTC for conveying large bore cannulae as required for current use with the artificial heart and left heart assist device. A total of 50 PTCs of varying designs and 6 controls were implanted in the dorsum of canines and goats. Observations with 6 initial designs indicated that necessary requirements in the design of a PTC, include adequate fixation and the use of dacron or nylon velour as the skin interfacing material. Best results were obtained utilizing a PTC having a polycarbonate extra-cutaneous flange, a nylon velour covered polycarbonate subcutaneous skirt, and an extended threaded central conduit to also allow fixation intrathoracicly behind the 2 ribs traversed by the device. Eight such PTCs have been implanted and without complications, have exhibited good tissue ingrowth and have had negative bacterial cultures for periods averaging 6 mos. The use of a PTC of this design should be considered in conjunction with mechanical hearts or left heart assist devices where large bore conduits must cross the chest wall and function on a chronic basis without allowing the ingress of virulent organisms.