{Reference Type}: Journal Article {Title}: A Case of Severe Aortic Stenosis after Aortic Valve Neocuspidization Using Autologous Pericardium (Ozaki Procedure). {Author}: Mikami T;Uchiyama H;Maeda T;Nakashima S;Satoshi M;Taku S;Araki E; {Journal}: Ann Thorac Cardiovasc Surg {Volume}: 29 {Issue}: 5 {Year}: Oct 2023 20 {Factor}: 1.889 {DOI}: 10.5761/atcs.cr.21-00269 {Abstract}: A 56-year-old man with a history of left nephrectomy for Wilms' tumor on chronic hemodialysis underwent aortic valve neocuspidization using autologous pericardium (Ozaki procedure) for aortic stenosis (AS) due to a bicuspid aortic valve 6 years ago. The AS gradually progressed and a decrease in the left ventricular ejection fraction was observed. Because of this, we decided to perform reoperative aortic valve replacement using a mechanical valve. Intraoperative findings showed severe calcification at the site where the autologous pericardium was sutured to the annulus. However, the degeneration of the valve leaflets themselves was mild. While excellent mid-term results have been reported for the Ozaki procedure, the long-term results are still unclear. In this case, the annulus was severely calcified, which reduced the mobility of the leaflet. We report the first case of AS progression requiring reoperation in the long-term period after the Ozaki procedure.