Study Background and Disease Burden
Mitral regurgitation (MR) is one of the most common valvular heart diseases worldwide and a significant contributor to morbidity and mortality. Despite advances in diagnostic techniques and surgical interventions, a profound understanding of the clinical presentation, procedural management, and outcomes in diverse patients referred for mitral valve surgery (MVS) remains incomplete. Data pertaining to “allcomer” populations undergoing surgery, reflecting real-world practice beyond highly selected clinical trial cohorts, are essential to assess guideline adherence, identify selection biases, and guide quality improvement initiatives. The MITRACURE International Registry was established to address these gaps by collecting comprehensive, multicenter data from consecutive adult patients undergoing MVS for MR in France and Canada during 2019.
Study Design and Methods
MITRACURE is a retrospective, observational registry capturing consecutive adult patients who underwent isolated or combined mitral valve surgery for mitral regurgitation in 2019 across 40 centers in France and Canada. Patients with isolated mitral stenosis or those having undergone prior mitral valve intervention were excluded to ensure cohort homogeneity focusing on MR-related surgeries. Data was meticulously abstracted from detailed clinical records and echocardiographic evaluations reported at the site level, allowing in-depth characterization of baseline patient profiles, MR etiology, surgical indication, procedural details, and in-hospital outcomes.
Key Findings
In total, 3522 patients underwent mitral valve surgery during 2019, with nearly half (48%) receiving combined procedures, predominantly along with other cardiac surgeries. The mean patient age was 65 years with a standard deviation of 12, and women constituted 35% of the cohort. Etiology was predominantly myxomatous degeneration (61%), followed by functional MR (9%), infective endocarditis (9%), and rheumatic disease (7%). Advanced echocardiographic quantification of MR severity was documented in only 43% of cases, reflecting potential variability in diagnostic rigor.
Clinically, a considerable proportion presented with advanced heart failure symptoms: 43% were classified within New York Heart Association (NYHA) functional class III or IV, 30% had congestive heart failure, and 47% received diuretic therapy. Rhythm disturbances were frequent, with 22% exhibiting atrial fibrillation or flutter. Importantly, left ventricular function was compromised (ejection fraction <50%) in 35%, and 22% of patients had pulmonary hypertension defined as systolic pulmonary artery pressure ≥50 mm Hg.
Guideline-directed early intervention was notably rare, with only 3% of patients undergoing surgery during early stages of MR according to class I or IIa indications. Surgical repair was achieved in 62% overall, but much higher in myxomatous cases (80%), underscoring etiology-dependent feasibility of repair versus replacement. The in-hospital mortality rate was 4.5% across all patients but significantly lower at 2.3% among those with myxomatous MR (1.8% for isolated repair, 3.1% combined procedures).
Expert Commentary
These findings underscore a prevalent pattern of late referral and advanced disease presentation in patients undergoing mitral valve surgery for MR in real-world settings. Despite clinical practice guidelines advocating early intervention in suitable candidates to prevent adverse remodeling and heart failure progression, the study reveals limited adoption in routine care. This delay likely contributes to the reduced repair rates and higher perioperative mortality observed compared to clinical trial populations or expert centers.
Notably, the distinction between etiologies is crucial; myxomatous MR patients had more favorable surgical outcomes and repair feasibility, reflecting the pathophysiology and surgical complexity differences relative to functional or infectious causes. The relatively low use of quantitative MR assessment might impact surgical decision-making and timing. Furthermore, the substantial proportion of combined surgeries suggests a population with complex comorbid cardiac pathology, which may elevate operative risks.
Limitations of the registry include its retrospective design and potential variability in data completeness and echocardiographic assessments across centers, which might affect the generalizability and uniformity of findings. Nonetheless, MITRACURE offers invaluable insights into contemporary European and North American MVS practice patterns and outcomes.
Conclusion
The MITRACURE International Registry provides a comprehensive, real-world overview of clinical presentation and outcomes following mitral valve surgery for MR, highlighting significant gaps in early intervention and opportunities for improving repair rates and patient survival. These results emphasize the imperative to refine diagnostic strategies, promote timely surgical referral, and tailor management based on MR etiology to optimize outcomes. Future efforts should focus on enhanced adherence to guideline recommendations, systematic MR quantification, and multidisciplinary approaches to mitigate advanced disease and improve quality of care in patients with mitral regurgitation.
References
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 Aug 31. doi: 10.1161/CIRCULATIONAHA.124.073674. Epub ahead of print. PMID: 40886109.
Otto CM, Nishimura RA, Bonow RO, Carabello BA, Erwin JP 3rd, Gentile F, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2021 Feb 2;143(5):e35-e71. doi:10.1161/CIR.0000000000000923.
Baumgartner H, Falk V, Bax JJ, de Bonis M, Hamm C, Holm PJ, et al. 2017 ESC/EACTS Guidelines for the Management of Valvular Heart Disease. Eur Heart J. 2017 Sep 21;38(36):2739-2791. doi:10.1093/eurheartj/ehx391.
