Background-Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry. Key Words: bioprosthesis Ⅲ transcatheter aortic valve implantation Ⅲ valve-in-valve M ore than 200 000 surgical aortic valve replacements (SAVR) are performed annually worldwide, with a substantial shift toward the use of bioprostheses rather than mechanical valves. 1 Bioprostheses have limited durability, and most are expected to degenerate and eventually fail within 10 to 20 years. 2-4 As a result, it is estimated that in the subsequent few years, many patients will suffer from failed surgical bioprosthetic valves. Reoperation, the standard of care for these patients, is occasionally a high-risk procedure that carries significant mortality and morbidity risks, especially because many of these patients are elderly and have numerous comorbidities. [5][6][7] Continuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz. Methods and Results-The