Recent progress in transcatheter interventions and minimally invasive surgery has broadened the therapeutic landscape, enabling treatment of patients traditionally considered higher risk and allowing earlier intervention in valvular disease with meaningful clinical benefit. This shift has influenced guideline recommendations in recent years, promoting earlier referral—both for surgery and, when feasible, for transcatheter approaches.

Within this context, the MITRACURE registry offers a real-world snapshot of everyday clinical practice in patients referred for mitral valve surgery. This retrospective, multicenter, consecutive cohort includes all patients referred for surgical treatment of mitral regurgitation (MR) across 40 centers in France and Canada. A total of 3522 “all-comer” patients were enrolled, excluding those with isolated mitral stenosis, minors, and reoperations during 2019—thereby avoiding distortions related to the COVID-19 pandemic. One notable observation is the limited proportion of low-volume centers (<50 annual mitral procedures), accounting for only 22%—likely reflecting the more centralized nature of public health systems compared with the United States.

Mean patient age was 65 years, 35% were women, and only 8% had known coronary artery disease. Myxomatous disease predominated as the MR etiology (61%, increasing to 73% in isolated surgery), while functional MR represented only 9%. Importantly, full quantitative echocardiographic assessment of MR severity was available in just 43% of referred patients—highlighting persistent reliance on qualitative or semiquantitative methods despite guideline emphasis on quantitative evaluation. Functional status at referral was also concerning: 43% were in NYHA class III–IV, and early surgery was uncommon, with only a minority undergoing intervention before developing class I/IIa triggers such as pulmonary hypertension, left ventricular dysfunction (LVEF <60%), or significant ventricular dilation.

Most operations were elective (83%), with urgent and emergent procedures constituting the remainder. Despite repair being the preferred intervention for degenerative MR—and the high expertise of participating centers repair rates typically reported at 90–95%—only 62% of patients in the registry underwent repair. Nevertheless, 80% of patients with myxomatous disease received a successful repair. Concomitant AF ablation or left atrial appendage occlusion was infrequent and therefore not classified as combined surgery for registry purposes.

In-hospital mortality reached 4.5% overall but was <1.5% among patients with isolated myxomatous disease—higher than mortality reported in high-volume expert surgical series and reflecting the increased clinical complexity of real-world populations.

Importantly, registry outcomes did not differ meaningfully between France and Canada, suggesting comparable performance across the two public health systems.

COMMENTARY:

Several key insights can be drawn from the MITRACURE registry regarding the current state of mitral valve surgery and the pathways leading to intervention.

First, the referral process remains slow, with many patients presenting only after substantial deterioration in functional capacity. This delay inevitably increases surgical risk and adversely affects postoperative outcomes. The persistence of a therapeutic mindset in which surgery is viewed as the final step—after the exhaustion of medical options—likely contributes to this pattern. Mild but progressive functional decline is frequently underappreciated, resulting in patients reaching surgery with higher comorbidity burden and greater operative risk, particularly in the context of combined procedures.

Second, the registry shows an unexpectedly low proportion of women (35%) despite similar prevalence of MR in both sexes. This discrepancy points toward a potential referral bias that warrants further investigation, as delayed or missed referral may disproportionately affect women.

Third, quantitative echocardiographic assessment of MR severity remains underused. Although quantitative techniques require time and expertise, reliance solely on qualitative or semiquantitative parameters may underestimate MR severity—especially in patients with suboptimal acoustic windows or eccentric jets—thus delaying surgical referral. Advanced multimodality imaging, including cardiac magnetic resonance, should be integrated when echocardiographic quantification is limited, as it provides robust volumetric assessment in this subset of patients.

Fourth, the modest repair rate observed in the registry illustrates a major challenge. Mitral valve repair, when feasible, preserves ventricular geometry and facilitates more efficient myocardial function, making it the preferred strategy for degenerative MR. While not all valves are repairable, the low overall repair rate suggests room for improvement. Regional assessment of surgical programs and the potential creation of high-volume reference centers may help optimize repair rates and outcomes, especially in borderline or anatomically complex cases.

Finally, the registry’s design introduces inherent limitations: its retrospective nature, the voluntary participation of centers, heterogeneity in available variables, and the absence of standardized minimal datasets across institutions. Moreover, information regarding patients evaluated but not accepted for surgery is not captured. Nonetheless, the registry still represents approximately half of all MV surgical procedures performed in France and Canada, offering meaningful insight into real-world practice.

Overall, the MITRACURE registry delivers a valuable contemporary overview of mitral valve surgery and highlights actionable targets for improvement. Earlier referral, broader adoption of quantitative imaging, and greater emphasis on repair strategies may collectively reduce mortality and enhance postoperative results. The importance of local and national registries—such as RECC—to identify system-specific gaps is clear. Despite its limitations, MITRACURE provides a highly relatable picture for many healthcare systems and encourages critical reflection on referral patterns, timing of intervention, and procedural strategy in MR management.

REFERENCE:

Messika-Zeitoun D, Chu MWA, Bouchard D, Le Tourneau T, Ternacle J, Demers P, et al.; MITRACURE Investigators. Clinical Presentation and Outcomes After Surgery for Mitral Regurgitation: Real-World Insights From the MITRACURE International Registry. Circulation. 2025 Sep 30;152(13):927-938. doi: 10.1161/CIRCULATIONAHA.124.073674.