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Page 16 of 20 Nappi et al. Vessel Plus 2021;5:40 https://dx.doi.org/10.20517/2574-1209.2021.06

A survey reported in a French study and published more than three decades ago found a greater use of
mitral valve re-repairs than replacement. However, several other studies showed that the percentage of
patients in whom repair was feasible ranged 36%-85%.

Repeat open mitral valve replacement is preferred in patients who require a second operation for
endocarditis, mitral stenosis, bileaflet prolapse or severe degenerative progression of native disease [8,29,30,32] .

In this scenario, short-term quality metrics can be determining factors in influencing surgical decision-
making because they directly affect the financial situation of the institutions and the employer/health
provider relationship. For example, these metrics have driven the choice for patients who received mitral
valve replacement surgery with bioprosthetic valves being preferred for the avoidance of anticoagulant
therapy and despite the risk of structural deterioration.

It is important to note that to date the expense for the treatment of thrombotic complications after standard
surgery mechanical prostheses is “not negligible”, as evidenced by the United States Center for Medicare &
Medicaid Services.

Nevertheless, a study from Harvard reporting the 24-year experience of 520 patients who were reoperated
after preceding MV replacement or MV repair showed that the use of a repeat mitral valve replacement
increased operative mortality (7.1%) or other major morbidity (18.2%). Moreover, the use of the mitral valve
repair, instead of the replacement, revealed a higher long-term survival, as noted with a Cox-adjusted
analysis.

[22]
It is clear that repeat mitral valve replacement is burdened by higher mortality, as shown by Suri et al. ,
[46]
[44]
[36]
Anyanwu et al. , David et al. (6.9%), Borger et al. (9%) and Vohra et al. (12%), at over 10-year
[5]
follow-up. Concerns related to the survival benefit at 30 days are due to: (1) largely increased technical
problem relative to reintervention; (2) increased frailty of patients undergoing reoperation; and (3) the fact
that prosthetic valve endocarditis is a usual indication for repeat surgery. In this group, the slightly superior
operative mortality and inferior long-term survival in patients who received a homograft may affect the
long-term results.
The evidence produced previously indicates that contemporary mitral valve redo surgery should involve
both the use of the standard approach and TMViV/R therapy - the latter in the absence of clinical or
anatomic contraindications - and substantial efforts should be made to raise the promotion of TMViV/R
therapy using transfemoral/transatrial approach in inoperable/high risk patients.

The increasing use of bioprostheses even in young patients has changed the platform for mitral valve
interventions and TMViV/TMViR could be considered similar alternatives in patients with degenerated
mitral and ring bioprostheses or MAC. However, concerns remain over the widespread use of TMViV/R
because of the lack of solid evidence on the durability of these devices implanted in the mitral position as
well as the potential risk of LVOT obstruction. Early outcomes of TMVR indicate that the procedure should
be preferred in high-risk cases because it has low periprocedural mortality. In addition, the occurrence of
early complications such as embolization, frequent paravalvular leaks with either C- or D-shaped rings and
obstruction of the left ventricular outflow tract due to malposition of the device must be taken into account.