Mitral Regurgitation: Choosing Between Surgery and Transcatheter Treatment?

Minimally Invasive Mitral Surgery: Identifying the Determinants of Operative Success

With the aging population, managing mitral regurgitation (MR) requires surgeons to perform a precise risk assessment. The choice between repair and replacement, as well as the surgical approach, depends on critical markers: an effective regurgitant orifice area (EROA) ≥ 20 mm², a left atrial diameter ≥ 55 mm, or a left ventricular end-systolic diameter (LVESD) ≥ 40 mm. While mitral valve repair remains the "gold standard", the emergence of minimally invasive surgery (MIMVS) promises a reduction in operative trauma and accelerated recovery, particularly in fragile patients with severe comorbidities.

The objective of this study is to precisely identify the comorbidities and anatomical configurations that impact the outcomes of MIMVS. The authors analyze the influence of these factors on early complications — such as repair failure, hospital mortality, and major complications — as well as on late outcomes, including recurrence of regurgitation or the need for reintervention. The central hypothesis is based on the fact that MIMVS constitutes a reproducible and less deleterious alternative to median sternotomy, provided that the preoperative variables conditioning ventricular remodeling and the stability of the valvular reconstruction are mastered.

A rigorous synthesis of the literature (2018-2024)

This systematic review, conducted according to PRISMA guidelines, is based on an analysis of the PubMed database up to January 31, 2025. The authors selected randomized clinical trials (RCTs), observational studies, and case reports published in English and German, covering an effective research period of six years.

Of 2,867 articles identified, 164 publications were included, totaling 222,947 patients (96,682 women and 126,265 men). The selection is segmented as follows:

• 8 publications specifically targeting Barlow's disease.
• 19 comparative studies between minimally invasive mitral valve surgery (MIMVS) and conventional sternotomy.

Data extraction was performed by the first author and verified by the last author via Microsoft Excel 2024. To standardise the analysis, a default threshold of 35% was applied for all left ventricular ejection fractions (LVEF) deemed "very low". The evaluation focuses on perioperative outcomes (clamping time, cardiopulmonary bypass), hospital mortality, and late complications such as recurrence of regurgitation or the need for reintervention.

Literature review and cohort profile

Out of a total of 2,867 articles initially identified, this systematic review included 164 publications (94 from PubMed and 70 from secondary literature) covering the last six years (2018-2024). This rigorous selection made it possible to compile data from 222,947 patients operated on for mitral valve pathology, whether of primary or secondary etiology.

Thematic focus and data standardisation

L'analyse révèle une hétérogénéité dans les objectifs des études incluses, allant de l'évaluation de la qualité de vie postopératoire à la comparaison entre chirurgie robotique et mini-invasive conventionnelle. Pour assurer la cohérence de l'analyse statistique, les auteurs ont appliqué une normalisation pour les patients présentant une fraction d'éjection ventriculaire gauche (FEVG) très basse, fixée arbitrairement à 35 % pour cette catégorie.

• Pathology diversity: Cohorts include primary mitral regurgitation (degenerative, Barlow, endocarditis) and secondary mitral regurgitation (ischemic or non-ischemic cardiomyopathies).
• Safety criteria: The conversion rate to sternotomy was systematically recorded as a major safety criterion for minimally invasive surgery (MIMVS).
• Time range: Although the review focuses on publications from the last 6 years, the reported data span a period of 23 years for certain follow-ups.

The authors emphasize that, although populations vary in size, the focus is on the impact of comorbidities (chronic kidney disease, hypertension, diabetes) on 30-day outcomes and in-hospital mortality.

Summary of results

This systematic review, including 164 studies for a total of 222,947 patients, confirms that native mitral repair remains the gold standard, offering better short- and long-term results than valve replacement. The minimally invasive approach (MIMVS) is established as a safe and reproducible alternative to sternotomy, reducing surgical trauma and accelerating postoperative recovery, particularly in elderly or comorbid patients.

In concrete terms, for the practitioner:

• Respect intervention thresholds: A left atrial diameter ≥ 55 mm or a LV end-systolic diameter (LVESD) ≥ 40 mm are critical indicators requiring rapid management to prevent irreversible remodeling and arrhythmias.
• Prioritize native repair: Undersized annuloplasty is the technique of choice; replacement should only be considered if echocardiography predicts a high risk of residual or recurrent regurgitation.
• Integrate the atrial fibrillation (AF) factor: Consider AF as a biomarker of early remodeling associated with less favorable postoperative outcomes, requiring increased vigilance regarding surgical timing.

Technical lexicon of the study

MIMVS (Minimally Invasive Mitral Valve Surgery): Mitral surgical approach via mini-thoracotomy aimed at reducing tissue trauma, costs, and recovery time compared to conventional median sternotomy.

Primary Mitral Regurgitation (Primary MR): Intrinsic damage to the components of the valvular apparatus (chordae, papillary muscles, leaflets), including infectious endocarditis, rheumatic fever, or connective tissue disorders.

Mitral annular calcification: Degenerative process of the mitral annulus, particularly frequent in elderly populations in the West, influencing the feasibility of repair versus replacement.

Atrial Fibrillation (AF): Comorbidity identified as a catalyst for early remodeling processes, correlated in this synthesis with less favorable postoperative outcomes after mitral intervention.

LVEF (Left Ventricular Ejection Fraction): Indicator of ventricular systolic function; the authors highlight that a preoperative LVEF ≤ 60% is a marker of poorer prognosis after surgery for severe mitral regurgitation.

EROA (Effective Regurgitant Orifice Area): Effective regurgitant orifice area measured by echocardiography; a value ≥ 20 mm² is associated with increased mortality according to reported data.

LV remodeling: Structural changes of the left ventricle (such as annular dilation) characteristic of secondary mitral regurgitation, often dictating the choice between valve repair and replacement.

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