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Echarte-Morales et al. Vessel Plus 2021;5:54 https://dx.doi.org/10.20517/2574-1209.2020.105 Page 3 of 13

Table 1. Morphological characteristics of the mitral valve and its impact on successful mitral valve repair
Condition Ideal Permissive Non-permissive
Affected leaflet Posterior Anterior or both Both
Leaflet calcification None Mild Moderate-severe
Ring calcification None Mild-moderate Severe
Subvalvular Normal Mild diffuse or moderate focal thickening Severe and diffuse thickening with retraction
apparatus
Regurgitation Carpentier II (FED or focal Carpentier I (IE) Carpentier I (active IE with severe MV
mechanism prolapse) Carpentier II (Barlow disease) destruction)
Carpentier III (mild restriction/thickening Carpentier IIIA (severe calcification of both
of leaflets) leaflets)
Carpentier IIIB (severe restriction, inferior wall
aneurysm)
Other features None Previous heart surgery, congenital Papillary muscle rupture, MV reoperation with
anomalies severe tissue loss

FED: Fibroelastic deficiency; IE: infective endocarditis; MV: mitral valve; MVr: mitral valve repair.

[12]
mainly driven by a high MR recurrence (58.5% vs. 3.8%) .

Quantification of MR requires the integration of quantitative and qualitative echocardiographic parameters
and can be particularly challenging after MVr due to the distortion of native MV anatomy and the
shadowing of the implanted annulus. To date, 2D and 3D contract vein are the quantitative parameters with
highest evidence.

Recurrence of mitral regurgitation after surgery
Mitral valve repair
Overall, recurrence of MR after MVr occurs in approximately 10%-30% of patients in long-term follow-
up . Technical issues may lead to early MR recurrence, while long-term MVr failure is usually a
[5]
consequence of progression of the underlying MV disease . Many factors may impact the probability of
[13]
MR recurrence after MVr, including the etiology of MR, the case volume experience of the operator team,
the surgical technique, anatomical features of the MV, and clinical comorbidities. Some of these factors are
summarized in Table 2, grouped by the etiology of MR.

In the studies carried out during the first decade of this century, only 50% of patients with PMR undergoing
MVr remained free of moderate to severe MR over long-term follow-up. However, as a result of the
improvement in MVr techniques in recent years, the recurrence rate has decreased substantially, being as
low as 13.3% at 15 years in some series . Conversely, results of MVr in SMR are much more modest,
[14]
especially in ischemic SMR, and recurrence of significant MR may exceed 50% at 2-year follow up even in
[12]
the setting of RCT and high-volume centers . In fact, operator’s procedural volume has shown to be a
major independent determinant of outcomes. In a recent study including 5745 patients with PMR, more
surgical experience was independently associated with longer survival and reduced need for MV
reoperation within 12 months of follow-up (HR = 0.45, 95%CI: 0.26-0.76, P = 0.003) .
[15]

Beyond its frequency, recurrence of moderate to severe MR after MVr has been consistently associated with
an increased mortality. In two recent observational series, one including 1218 patients with PMR and
another one analyzing 261 subjects with SMR, MR recurrence after MVr was significantly related to an
increased risk of death in both reports (PMR: HR = 1.72, 95%CI: 1.24-2.39, P = 0.002; SMR: HR = 3.28,
[5]
95%CI: 1.87-5.75, P < 0.001) .