Minimally invasive mitral surgery: the challenge of sex disparities in the OR

Gender inequalities in the management of mitral regurgitation

Mitral regurgitation (MR) remains one of the most frequent valvular heart diseases worldwide, affecting approximately 1% of the population over 55 years of age. While the overall epidemiology is well documented, a persistent disparity appears in the care pathway for female patients. In clinical practice, women seem less likely to undergo surgery for mitral valve prolapse compared to men, while presenting a higher risk of postoperative mortality, regardless of the chosen surgical access (median sternotomy or minimally invasive techniques).

This literature review specifically examines the influence of sex on the management of MR, with a focus on minimally invasive mitral valve surgery (MIMVS). The objective is to synthesize current evidence regarding differences in clinical presentation, diagnostic evaluation, and intervention strategies between men and women. The authors aim to determine how these factors influence the eligibility and outcomes of female patients candidates for mitral repair via a reduced thoracic approach, while identifying major gaps in current scientific data on female-specific health outcomes in this field.

Review methodology

This literature review synthesises the evidence regarding sex-related disparities in the management of mitral regurgitation (MR) and valvular surgery. It analyses the pathophysiological mechanisms according to the Carpentier classification (Types I, II, IIIa and IIIb) as well as various surgical access modalities, including median sternotomy, right minithoracotomy, hemisternotomy, and transapical, robotic or endoscopic approaches.

The evaluation is based on the compilation of clinical study results comparing male and female populations according to several methodological axes:

• Comorbidities and clinical presentation: analysis of the NYHA stage, the prevalence of atrial fibrillation, heart failure and the impact of obesity (BMI > 30 and > 40).
• Care pathway: evaluation of the frequency of multidisciplinary discussions, intervention lead times, and the proportion of investigations performed during hospitalisation.
• Data analysis: use of odds ratios (OR) and 95% confidence intervals (CI) to identify disparities in treatment and postoperative mortality.

The synthesis also examines the influence of extensive imaging and the indexing of parameters to body surface area (BSA) on the definition of MI severity and surgical eligibility.

Disparities in assessment and access to care

The data compiled in this review highlight a significant gender bias starting from the preoperative phase. Women are markedly less likely to be discussed in multidisciplinary team (MDT) meetings compared to men, with an odds ratio (OR) of 0.27 (95% CI: 0.15–0.47; p < 0.001). This underrepresentation is correlated with later management, often during emergency hospitalisation, despite a more symptomatic clinical presentation.

Specific clinical and morphological profile

Analysis of anatomical characteristics and comorbidities reveals major differences between the sexes:

• Comorbidities: Female patients present higher rates of congestive heart failure and atrial fibrillation at the time of surgery.
• Anatomy: Post-mortem studies indicate lower annular elasticity and a larger indexed circumference in women.
• Pathology: Women more frequently present with mitral stenosis as an operative indication (particularly for valve replacements) and complex forms of myxoid degeneration (anterior or bivalve prolapse).
• Obesity: More than 50% of patients with a BMI > 30 or ≥ 40 are women. Morbid obesity (BMI > 40) is associated with a marked increase in length of stay and hospital mortality.

Intervention thresholds and imaging

The synthesis shows that surgical criteria differ by gender, often to the disadvantage of female patients. Women are primarily operated on for symptomatic management (72% compared to 57% for men), but much less frequently based on isolated echocardiographic criteria.

Surgical trigger criteria	Men (%)	Females (%)
Left ventricular (LV) dilation alone	11 %	4 %
LVESD ≥ 40 mm (asymptomatic patients)	9.9%	4.1%

On magnetic resonance imaging (MRI), women present lower ventricular volumes (left and right) than men, even after indexing to body surface area. This trend frequently leads to classifying mitral regurgitation as "moderate to severe" rather than "severe", thus delaying intervention despite abnormal ventricular remodeling already being underway.

The analysis of this review suggests that women experience a multifactorial delay in management. Biologically, intrinsic variations in extracellular matrix remodeling predispose female patients to complex forms of bileaflet prolapse, whereas surgical durability is classically superior on the posterior leaflet. Clinically, the predominant reliance on symptoms as a trigger for intervention is problematic. Patients are often operated on at an already advanced stage of ventricular remodeling, which could explain the excess postoperative mortality observed compared to men. This phenomenon is accentuated by a blatant under-representation of women in multidisciplinary evaluations, potentially depriving them of early access to specialized mitral repair centers. Finally, the study highlights a significant gap in the literature: few studies specifically investigate the outcomes of minimally invasive surgery (MIMVS) in women. However, the reported anatomical differences (lower annular elasticity) could influence repair strategies and the choice of annuloplasty material.

Summary of results

This review highlights a major gender bias in the management of mitral regurgitation: female patients are significantly less likely to be referred for multidisciplinary evaluation (OR 0.27; p < 0.001). They present with more advanced pathologies, with an increased prevalence of heart failure and atrial fibrillation, leading to higher postoperative mortality compared to men.

In concrete terms, for the practitioner:

• Screening adjustment: Be proactive in patient referral, as left ventricular dilatation thresholds on imaging may underestimate the actual severity of the condition in women.
• Early management: Refer to an expert center as soon as the first symptoms appear to avoid interventions at the stage of severe comorbidities (decompensated heart failure).
• Surgical planning: Anticipate increased complexity due to delayed diagnosis, more frequently requiring concomitant procedures such as atrial fibrillation ablation or tricuspid surgery.

Technical lexicon

Myxoid degeneration: Alteration of the valvular connective tissue leading to excess leaflet and structural collapse, more common in women in bivalve forms.

Rheumatic heart disease: Chronic inflammatory valvular involvement, identified in this review as having a higher prevalence in female patients.

Atrial fibrillation (AF): Supraventricular rhythm disorder often secondary to advanced MR, frequently requiring concomitant ablation during mitral surgery.

Primary mitral regurgitation (PMR): Regurgitation caused by an intrinsic abnormality of the valvular apparatus (leaflets, chordae), as opposed to functional causes.

Secondary mitral regurgitation (SMR): Valvular leakage resulting from remodeling or dilation of the cardiac chambers, the valve itself being initially healthy.

Carpentier Classification: System classifying mitral leaflet mobility (normal, excessive, or restricted) to guide the surgical repair strategy.

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