Structural Valve Deterioration in Transcatheter Aortic Bioprostheses: Diagnosis, Pathogenesis, and Treatment.

Transcatheter aortic valve replacement has emerged as the preferred treatment modality in most patients with severe aortic stenosis. With its global adoption and broader application in younger and healthier patients, the issue of transcatheter bioprosthetic valve degeneration and its impact on valve durability continues to earn clinical relevance. Differences in the pathophysiologic processes that separate native from transcatheter heart valve deterioration remain poorly understood. When compared to surgical aortic bioprostheses, the mechanisms of valve degeneration are similar in transcatheter heart valves, with meaningful differences most noticeably found between the individual constructs of their design. Recognizing the clinical and hemodynamic presentation of structural valve degeneration remains paramount. The recently revised consensus guidelines that incorporate the integration of advanced multimodality imaging with invasive hemodynamics represent a major step forward in our ability to accurately diagnose bioprosthetic valve degeneration, and to identify differences in durability patterns, and to establish treatment recommendations for the lifetime management of patients with aortic stenosis. Parallel efforts to unmask the biomolecular differences in atherosclerotic plaque burden, valve calcification, and thrombotic diathesis, including host immunocompetence, between the different available bioprostheses, will further advance the role of emerging valve tissue technologies to improve durability. As with surgical heart valves, the optimal treatment options for redo-transcatheter aortic valve replacement and surgical explant remain poorly understood. Ongoing translational research in bench testing coupled with prospectively designed core lab-adjudicated clinical trials are much needed. This report provides a contemporary overview of transcatheter structural valve degeneration, including evolving concepts in its pathogenesis, diagnosis, and treatment.