Evaluation of Pericarbon valve prosthesis: in vitro, ultrastructural, and animal studies.

Pericarbon, a new generation pericardial valve, is characterized by a single, three cuspal shaped pericardium sheet, which is sutured to a second sheet lining the inner surface of the plastic, low profile stent. A coating of hemocompatible carbon film covers all the exposed, nonbiological surfaces. Optimal preservation of collagen and graft cells is achieved by fresh tissue glutaraldehyde fixation and cusp shaping without mold. Accelerated fatigue testing showed a duration of over 150 million cycles, a figure much higher than that observed when current pericardial and porcine valves were tested with the same apparatus. Results of long-term (greater than 7 months, average 10.5) implantation in 20 sheep (13 mitral, 7 tricuspid) disclosed no case of mechanical failure, mild to moderate primary calcification in older explants, and significant fibrous tissue overgrowth only in the tricuspid position. Transmission electron microscopy studies revealed collagen and elastic fiber integrity, no significant plasma protein insudation, and well-preserved graft cells. Re-endothelialization by host cells was a regular finding on scanning electronic microscopy. Early ultrastructural nuclei of calcification were seen mostly on collagen fibers. Pericarbon presents basic changes in pericardial valve design, and optimal morphological preservation is obtained after industrial processing. Accelerated fatigue tests in vitro show long duration. At medium long-term animal experimental follow-up, mechanical failure was not observed; significant host tissue reaction occurred in the tricuspid but not in the mitral position; primary calcification increased progressively with time and involved mainly collagen fibers.