Long-Term Durability of Paediatric Mitral Valve Repair: Balancing Stenosis and Regurgitation

OBJECTIVES: Mitral valve repair (MVR) is the preferred surgical approach for paediatric mitral valve disease, but predictors of long-term durability remain poorly defined. We aimed to describe long-term outcomes after MVR in children and to identify echocardiographic predictors of mitral valve reintervention. METHODS: We retrospectively reviewed all consecutive patients younger than 18 years who underwent MVR between 2000 and 2024 at a single tertiary centre. Patients with atrioventricular septal defects or single-ventricle physiology were excluded. Preoperative and predischarge echocardiography assessed mitral regurgitation grade and mean transmitral gradient. Clinical and echocardiographic follow-up data were reviewed and analysed. Reintervention was analysed using competing-risk methods including postoperative mean transmitral gradient and residual mitral regurgitation at discharge. RESULTS: A total of 112 children were included (age range 5 days to 17 years; body weight 2.3-100 kg). Operative mortality was 0.9% (n = 1), late mortality 3.6% (n = 4), and one patient underwent heart transplantation. The cumulative incidence of mitral valve reintervention was 27.5%, 32.9%, 46.6%, and 46.6% at 5, 10, 15, and 20 years, respectively. In the Fine and Gray model, higher postoperative mean transmitral gradient was associated with an increased cumulative incidence of reintervention (subdistribution hazard ratio [sHR] 1.26 per 1 mm Hg, 95% confidence interval [CI] 1.16-1.38; P < .001), whereas moderate-or-greater residual mitral regurgitation at discharge was not significantly associated (sHR 0.54, 95% CI 0.25-1.17; P = .12). Death and/or heart transplantation events were rare during follow-up. CONCLUSIONS: In this paediatric cohort, MVR was associated with low operative mortality and satisfactory long-term survival, but reintervention represented the main late risk. Higher postoperative mean transmitral gradient was associated with reduced valve durability, whereas moderate-or-greater residual regurgitation was not independently associated. These findings support efforts to minimize postoperative transmitral gradients when feasible while individualizing the balance between residual stenosis and regurgitation according to valve pathology and repair complexity.