The development of the prosthetic heart valve has led to the evolution of cardiac intensive care units, a better understanding of cardiac function and biocompatible materials, and new surgical procedures. Initial efforts with formaldehyde-fixed valves did not have long-term success. They led to the development of the stabilized glutaraldehyde process (SGP) valve and the flexible stent. The safety and efficacy of a heart valve bioprosthesis has been demonstrated through laboratory and animal experiments. Data on long-term clinical implants are needed to validate the results of these experiments.