Outcome of primary mitral valve surgery in pediatric patients: Results from a bi-centric study.

OBJECTIVES: Due to heterogenous mitral valve(MV) disease expression, primary MV surgery in children might be challenging, entailing suboptimal results. METHODS: In this bi-centric collaboration all children undergoing primary MV surgery from 1987 to 2023 were included. Patients with atrioventricular septal defect and univentricular physiology were excluded. Study end-points were survival and need for MV reoperation and/or replacement, including multivariable risk factor analysis. RESULTS: Overall 109 patients underwent 158 procedures for predominantly mitral regurgitation(MR)(n = 82, 74.5%) and stenosis(MS)(n = 27, 25.5%), respectively at a median age of 5.7y(IQR 1.6-12) and 0.6y(IQR 0.3-1.2)(p < 0.001). Associated cardiac procedures were performed in 49(45.0%) patients. Primary repair was successful in 103(94.5%) patients, but required 10 early reinterventions(4 re-repair and 6 replacement). Overall 5-year survival was 83.2±4.0% without difference between MV phenotypes(p = 0.871). Risk factors for mortality were MV repair in the first year of life, associated intracardiac correction, and open chest or need for ECMO at completion of surgery. The cumulative incidence of MV reoperation and replacement at 5 years were respectively 27.0±4.7% and 16.5±4.0%, in disadvantage of MS phenotype. MV repair during infancy, MS phenotype, use of commissural or Alfieri-repair and the need for early MV re-repair were significant predictors for later MV reoperation or replacement. CONCLUSION: Although primary mitral valve surgery in children remains challenging, an acceptable repair is achievable in more than 90%. Whereas younger age at repair is a strong predictor of clinical outcome, repair durability is equally depending on the type of MV disease in disadvantage of the stenosis phenotype.