Transcatheter mitral valve replacement for degenerated mitral bioprostheses: a systematic review

Background: Treatment of degenerated mitral bioprostheses with transcatheter mitral valve-in-valve (MVIV) implantation is increasingly used. The goal of this review was to evaluate the one-year outcomes of this therapy using the most recent evidence. Methods: A MEDLINE, Cochrane database and SCOPUS search was performed of published observational studies involving patients undergoing transcatheter MVIV for degenerated bioprosthesis to determine procedural success, thirty-day and one-year survival. Results: A total of 2,684 patients undergoing transcatheter MVIV were identified from five studies with mean age of 73-75 years, 57-63% female and Society for Thoracic Surgery (STS) risk score ranging from 9-13%. Procedural technical success ranged from 94-98%, with 1-3% rates of periprocedural death, 0-2% stroke and 1-5% risk of left ventricular outflow tract (LVOT) obstruction. Thirty-day post-procedure mean mitral prosthetic gradient ranged from 6-7 mmHg and residual mitral regurgitation was mild or less in 96- 100% of patients. Thirty-day survival and one-year survival ranged from 93-97% and 83-89% respectively. Conclusions: Transcatheter MVIV is an effective treatment for structural degeneration of biologic mitral valve replacement with low complication rates and favorable one-year outcomes. Accordingly, MVIV should be considered as a reasonable alternative to re-do surgical mitral valve replacement in high risk patients with comorbidities. Further study of long-term outcomes of this treatment is needed.