endocarditis, 1.475% /pt-yr, overall valve failure, 3.319% /pt-yr; and primary tissue failure, 1.475% /pt-yr. The actuarial probability of survival was 94.3$pm$3.6% and the probability of freedom from thromboembolism 90.6$pm$4.6% at 11 years after surgery respectively. And, the probability of freedom from primary tissue failure was 60.4$pm$16.9% also at 11 years The evidence of possible premature and accelerated failure of the pericardial valve in the aortic position among the young population was not clear on the age-related analysis of the structural failure, and no suggestion could be made to indicate age limit when the use of the pericardial valve would better be avoided.