BACKGROUND: We aimed to assess the impact of complex mitral valve disease and patient risk profile on operative outcomes in the large cohort of the Mini-Mitral International Registry.

METHODS: Patients were assigned to categories of complex degenerative mitral valve regurgitation (DMR; bileaflet or anterior mitral leaflet prolapse/flail) and simple DMR (posterior mitral leaflet prolapse/flail). Subgroup analyses was performed in low-risk (EuroSCORE II <8%) and high-risk (EuroSCORE II >8%) cohorts. A logistic regression model was applied to investigate the impact of valve anatomy and patient risk factors on valve repair rate and operative risk.

RESULTS: The study cohort consisted of 4524 patients with DMR (complex DMR, 1296; simple DMR, 3228). Valve repair rate was 87.3% and 91% in complex DMR and simple DMR, respectively. Predictors of valve replacement were anterior leaflet prolapse/flail, bileaflet flail, female sex, age, and reoperation, whereas Barlow disease was protective. Clinical results were comparable between complex DMR and simple DMR. On subgroup analyses, high-risk patients showed less satisfactory outcomes with respect to both the valve repair and operative mortality rates.

CONCLUSIONS: Our findings suggest that complex DMR can be satisfactorily addressed by minimally invasive techniques. However, whereas complex disease was associated with low operative risk, anterior leaflet lesions and bileaflet flail remain negative predictors of successful valve repair. Conversely, valve repair rate was less satisfactory in high-risk patients, regardless of DMR complexity.