Cardiac valve replacement in children: comparison of tissue with mechanical prostheses.

Replacement of cardiac valves in children has been associated with high rates of mortality and morbidity in the past. We have compared 24 children from 2 to 18 years of age who have received mechanical valves with 24 children who have received porcine valves. The groups were similar except that (1) there were more mitral operations in the mechanical valve group and more aortic operations in the porcine valve group; (2) more porcine than mechanical valves were implanted in recent years; and (3) the porcine valve group comprised more young patients under 8 years and required more complex operations. Early and late mortality rates were higher in the mechanical than in the porcine valve group. Major late complications were seen in 50 percent of the mechanical valve group and 13 percent of the porcine group. Implantation of an adult-sized aortic valve was made possible in all patients by the use of aortic augmentation annuloplasty. Higher operative mortality rates in the mechanical valve group may have been related more to technique of myocardial preservation during operation than to type of valve. Although differing rates of late morbidity and mortality may also have been related to myocardial preservation and other technical factors, the type of valve used seemed to be an important determinant of the better results in the porcine group. Despite unknown durability of the porcine valve, our data suggest that the safest prosthetic valve to use in children at this time is the glutaraldehyde-fixed porcine prosthesis.