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Page 4 of 13 Echarte-Morales et al. Vessel Plus 2021;5:54 https://dx.doi.org/10.20517/2574-1209.2020.105

Table 2. Predictors of regurgitation recurrence after mitral valve repair
PMR SMR
Elderly population Anterior and posterior myocardial infarction
Isolated prolapse of anterior leaflet Preoperative LVEDD > 70 mm
2
Advanced myxomatous degeneration Preoperative LVESD index > 45 mL/m
Lack of mitral annuloplasty, chordal shortening Coaptation depth at discharge ≥ 0.5 cm
Prolonged cardiopulmonary bypass time QRS > 120 ms prior to surgery
Low volume experience of operator team Short posterior tethering
Systolic pulmonary artery pressure ≥ 50 mmHg Interpapillary distance > 20 mm
Reduced LVEF Posterior mitral valve leaflet angle > 40°
PMR: Primary mitral regurgitation; SMR: secondary mitral regurgitation; LVEF: left ventricle ejection fraction; LVEDD: left ventricular end-diastolic
diameter; LVESD: left ventricle end systolic diameter.

Mitral valve replacement
Two main mechanisms can cause recurrence of MR after MVR: degeneration of bioprosthetic valves and
para-valvular leaks (PVL) in mechanical prosthesis. Bioprosthesis dysfunction is increasingly common since
its use has become more widespread in recent years [16,17] . The most frequent cause of bioprosthesis failure is
progressive degeneration of the valvular tissue, resulting in severe calcification of the leaflets that can lead to
prosthetic insufficiency or stenosis. Recent studies suggest that host immune response may play a major role
in the pathogenesis of structural valve degeneration, leading to a combination of rejection-like processes,
atherosclerosis, and calcification of native valves.

The annual incidence of PVL after MVR is estimated at 0.2%-1.4%, and it more frequently affects
mechanical prosthesis [18,19] . Severe MV annular calcification, endocarditis, connective tissue disease, and
[20]
continuous suturing have been associated with a higher incidence of PVL . Clinical symptoms vary and
range from asymptomatic to HF and/or hemolysis. In symptomatic patients, medical treatment often fails to
provide enough clinical relief and is associated with poor outcomes, prompting invasive management to fix
the leak .
[21]

Redo surgery for MR recurrence
Reoperation implies an increased rate of prolonged patient ventilation in the postoperative period, renal
failure, and stroke. Some of the factors associated with adverse events in this population are severe tricuspid
valve regurgitation, cardiogenic shock, the timing of the procedure, and concomitant myocardial
revascularization. Onorati et al. reported an operative mortality rate of 12.5% in a series of 832 patients.
[22]
The most frequent complications were acute myocardial infarction, acute respiratory failure, and acute renal
failure . Although some studies have described improvement in terms of adverse events in patients
[22]
reoperated upon due to the recurrence of MR, most of them have recorded important intra- and post-
operative mortality in such individuals .
[23]

Transcatheter therapies for MR recurrence after surgery
In recent years, there has been a huge development of percutaneous therapies to treat MR to offer an
[24]
alternative for symptomatic patients who were not deemed candidates for conventional MVS . Similarly,
most patients with recurrence of MR following MVS are at high risk for reoperation due to advanced age
and multiple comorbidities. In this setting, some transcatheter therapies offer an appealing less invasive
[5]
approach for these patients, who were previously managed conservatively with poor outcomes . These
therapies include PMVR, transcatheter mitral valve replacement (TMVR) [valve-in-ring (ViR) or valve-in-
valve (ViV)], and percutaneous PVL closure.