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Page 2 of 20 Nappi et al. Vessel Plus 2021;5:40 https://dx.doi.org/10.20517/2574-1209.2021.06

Keywords: Mitral valve, regurgitation, ischemic mitral, transcatheter, replacement, repair

INTRODUCTION
The increase in the number of mitral valve repair operations, with a rise in the number of biological
prostheses implanted in younger patients, has resulted in higher incidences of reoperative mitral valve
surgery. Bioprosthesis replacement for deterioration or failed repairs and mitral annular calcification
(MAC) pose ongoing challenges to the surgical management of patients requiring repeat valve surgery (Re-
MVS) .
[1-4]

There is currently evidence that the percentage of structural valvular degeneration (SVD) is 85% in patients
[1]
after previous MV surgery . In these cases, a second mitral valve surgery may be required in 35% of cases
[5,6]
within the first 10 years . For patients who have undergone primary mitral valve surgery, the greatest
concern falls on the best choice for the subsequent surgical therapeutic approach. The crossroads is
therefore represented between the choice of mitral valve reoperation using a standard surgical approach or,
alternatively, the transcatheter mitral valve implantation procedure. In addition, given the high risk and
prohibitive operative mortality for reoperation after mitral valve replacement operation (Re-MVRpl) or
mitral valve repair procedure (Re-MVRp), the search for an alternative to the standard surgical approach is
both judicious and desirable.

The literature has reported successful cases of transmitral valve-in-valve replacement (TMViVR) in
[7]
nonsurgical candidates in whom a mitral valve bioprosthesis or surgical repair failed .

The consolidated experience gained with the Sapien Transcatheter Heart Valve (Edwards Life Sciences,
Irvine CA) has led to accelerate legislative endorsement by the United States Food and Drug Administration
(FDA) which has authorized the use of transcatheter valve treatment (TVT) for the treatment of the
diseased mitral valve [8-11] .

As a result, it was possible to extend the indication for the use of these devices to Medicare and Medicaid
Services (CMS) patients. The well-defined role of NCD has left the heart team to create a nationally verified
prospective registry for each hospital.

Patients in whom therapy [transcatheter mitral valve-in-valve therapies (TMViV-T)] is recommended are
closely surveilled as part of the after-market monitoring and followed up to assess the quality of the results
produced at the individual level by the centers involved in TMViV-T.

The TMViV/TMViR module is one of three modules of the National Registry, the others being
transcatheter aortic valve replacement (TAVR). Instead, patients who are managed with transcatheter aortic
valve-in-valve are included in the TAVR module. The TMViV-T module gathers patients’ demographic
information and comorbidities. In addition, the TMViV/TMViR registry contains specific baseline criteria
to characterize mitral valve disease, reporting detailed notes on the procedure adopted as well as the results
on mortality and morbidity. Specifically, it reports mortality to 30 days and 1 year and provides information
on hospital admissions and quality of life. A risk model for the prediction of hospital mortality is also listed
in the United States National Registry which references the TMViV/TMViR module. It is useful to compare
the results reported both with national averages and with those obtained from peer groups, with the aim to
improve and refine the quality of the procedure. Mechanical intervention with the transcatheter approach
for structural degeneration of the mitral valve prosthesis or failure of MV repair can be performed using the