Mitral repair or replacement: what is the survival rate in severely dilated ventricles?

Surgical challenges of degenerative mitral regurgitation with severe ventricular dilatation

The management of complex degenerative mitral regurgitation (DMR) is made particularly delicate by associated left ventricular dilatation (LVD), defined by a left ventricular end-diastolic diameter (LVEDD) greater than or equal to 6.0 cm. Although mitral repair (mitral valve repair) is classically preferred to preserve cardiac architecture and avoid long-term anticoagulation, valve replacement (mitral valve replacement) is often discussed in cases where the durability of the repair seems compromised by advanced ventricular remodeling. The literature lacks precise comparative data in this specific patient profile, leaving the trade-off between the hemorrhagic risk associated with prostheses and the risk of recurrent valve leakage inherent to repair unanswered.

This retrospective study analyzed 150 patients presenting with DMR and severe LV dysfunction to evaluate mid-term postoperative clinical and echocardiographic results, with a median follow-up of 55.5 months. The authors test the hypothesis of equivalence in terms of overall survival between mitral valve repair and mitral valve replacement after propensity score matching (PSM). The objective is to quantify the impact of each strategy on hemorrhagic complications, residual systolic function—measured by left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS)—as well as the frequency of reinterventions, in order to better define the long-term clinical benefit of each surgical approach in this context of major remodeling.

Methodology: Retrospective analysis of 150 patients

This retrospective study evaluated short- and mid-term clinical results (median follow-up of 55.5 ± 21.0 months) after mitral valve surgery for degenerative mitral regurgitation (DMR) associated with severe left ventricular dilatation (LVD) (end-diastolic diameter ≥ 6.0 cm).

The initial cohort of 150 patients was stratified into two groups: mitral valve replacement (56.67%) or mitral valve repair (43.33%). Exclusion criteria included non-degenerative etiologies, concomitant aortic valve surgery, reinterventions, and coronary artery bypass grafting.

• Surgical strategy: The choice between mitral valve repair and mitral valve replacement was determined in the operating room by the surgical team based on the technical feasibility of the repair, leaflet anatomy, and the extent of ventricular remodeling. The repair included, depending on the case, resections, artificial chordae, or annuloplasties.
• Matching: To limit selection bias between the two groups, the authors used propensity score matching (PSM).
• Analyses: Echocardiographic parameters (cardiac dimensions, left ventricular ejection fraction, severity of leakage) and global longitudinal strain (GLS) were evaluated serially. Statistical comparisons were performed before and after propensity score matching. The primary endpoint was overall survival, while secondary endpoints included perioperative events, reinterventions, and hemorrhagic complications.

Results: Comparative analysis mitral valve repair vs. mitral valve replacement

This retrospective study included 150 patients with degenerative mitral regurgitation (DMR) associated with severe left ventricular dilatation (LVEDD ≥ 6.0 cm). The surgical distribution was 56.67% for mitral valve replacement and 43.33% for mitral valve repair. The cohort had a median age of 59 (17) years, with a male predominance (76.7%).

Clinical data and survival

The median clinical follow-up was 55.5 (21.0) months. Kaplan-Meier survival curves revealed no significant difference in all-cause mortality between the two groups, whether before propensity score matching (log-rank P = 0.175) or after (log-rank P = 0.497).

Echocardiographic parameters and complications

Postoperative analysis revealed significant discrepancies between the groups regarding several indicators of systolic function and valve performance:

• Residual mitral regurgitation: P = 0.017
• Left ventricular ejection fraction (LVEF): P = 0.005
• Global longitudinal strain (GLS): P = 0.023

Although left ventricular end-diastolic dimensions (LVEDD) and NYHA functional class remained comparable between the groups, major clinical disparities were observed. The MVR group was associated with a higher incidence of postoperative hemorrhages, directly correlated to the need for long-term oral anticoagulation. Conversely, the MVP group presented an increased risk of recurrence of mitral regurgitation.

Summary of observations

The study highlights that, despite comparable mortality, the preservation of subclinical systolic function (assessed by GLS and LVEF) is more favorable in the MVP group. These results suggest a long-term myocardial benefit for valve repair, although the risk of valvular recurrence requires rigorous monitoring.

Analysis of results

This retrospective study of 150 patients presenting with severe degenerative mitral regurgitation (DMR) with left ventricular dilatation (LVEDD ≥ 6.0 cm) provides a nuanced insight into the choice between repair (MVP) and valve replacement (MVR). The data show that, while overall survival is equivalent between the two groups (log-rank P = 0.497 after propensity score matching), complications differ significantly.

The mitral valve replacement group presents an increased incidence of postoperative hemorrhages, inherent to long-term anticoagulation. Conversely, the mitral valve repair group, while not exempt from risks, better preserves subclinical systolic function, with more favorable LVEF (P = 0.005) and GLS (P = 0.023) values. Valve repair is therefore part of a myocardial preservation strategy, despite a theoretical risk of recurrent mitral insufficiency.

Limitations and perspectives

The main limitation lies in the retrospective design and the heterogeneity of surgical techniques (conventional sternotomy vs. minimally invasive/robotic surgery). Although propensity score matching attempts to mitigate selection bias, the operative decision remained guided by the intraoperative assessment of technical feasibility. Finally, the median follow-up duration of 55.5 months remains moderate to fully evaluate the long-term impact on reverse remodeling.

Analysis of surgical strategies in degenerative mitral regurgitation with ventricular dilatation

This retrospective study of 150 patients shows equivalent mid-term survival between mitral valve repair (MVP) and replacement (MVR) in patients presenting with severe left ventricular dilatation (LVEDD ≥ 6.0 cm). While postoperative mortality is comparable, the MVP group shows functional systolic benefits, notably better ejection fraction and better global longitudinal strain (GLS), whereas the MVR group is burdened by a higher incidence of hemorrhages linked to long-term anticoagulation.

Concretely, for the practitioner:

• Prioritize mitral repair when technical feasibility is confirmed, in order to preserve subclinical myocardial function (GLS and LVEF) and avoid hemorrhagic complications linked to anticoagulants.
• Anticipate the risk of recurrence of mitral regurgitation after repair in case of advanced ventricular remodeling, requiring regular echocardiographic follow-up.
• In case of valve replacement, long-term anticoagulation imposes a strict benefit-risk balance in terms of major bleeding, particularly in this at-risk population.

Valvular pathology characterized by structural alteration of the mitral apparatus, compromising leaflet coaptation and inducing systolic regurgitation with chronic volume overload of the left ventricle. Morphological criterion selected in this study to define a left ventricular end-diastolic dimension (LVEDD) greater than or equal to 6.0 cm, reflecting advanced cardiac remodeling. Echocardiographic indicator of subclinical systolic function, measured here by speckle-tracking, showing more favorable values in the study after mitral repair compared to replacement. Statistical method applied in this study to balance initial characteristics between MVP and MVR groups in order to minimize selection bias during retrospective analysis. Serious adverse event (grade ≥2) requiring hospitalization, transfusion, or invasive intervention, statistically more frequent in patients on long-term oral anticoagulation after valve replacement. Surgical strategy favored in the study for its ability to preserve native tissues, improve reverse remodeling, and limit complications linked to anticoagulation, subject to anatomical feasibility.

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