The aortic valve may be replaced with an aortic homograft or a pulmonary autograft in children and young adults. The risk of surgery is low (2.5%). No anticoagulants are required, and thromboembolism is virtually unknown unless valve degeneration or endocarditis occur. Late follow-up indicates that approximately 85% of patients will be free of reoperation at 10 years when an aortic homograft is used and at 20 years when a pulmonary autograft is used.