Pediatric mitral valve replacement: incremental risk factors impacting survival and reintervention.

Background And Aim Of The Study: Predictors of survival and reintervention in children undergoing mitral valve replacement (MVR) were assessed.

Methods: A total of 37 children underwent MVR, with a mean prosthesis size of 22.5 mm.

Results: Six patients died during the study. Actuarial and event-free survivals (including operative mortality) at 10 and 20 years were 85 and 85%, and 55 and 37%, respectively. The linearized rate of bleeding was 0.67% per patient-year (pt-yr). There were no instances of thromboembolism, endocarditis or structural valve dysfunction. Six patients required reintervention for somatic outgrowth at a mean postoperative interval of 104 months. Freedom from reintervention at five, 10 and 20 years was 92, 73 and 48%, respectively. There were no deaths or complications following reintervention. The mean follow up was 96 months (range: 3 to 276 months); total cumulative follow up was 296 pt-yr. Multivariate predictors of mortality were age < 6 months, NYHA class IV, congestive cardiac failure, internal orifice diameter (IOD) < 14 mm and effective orifice area (EOA) < 1.5 cm2. Predictors for reintervention were age < 6 months (p = 0.0021), predicted annulus size < 16 mm (p < 0.0001), IOD < 18 mm (p = 0.05), IOD index (IODI) > 50 mm/m2 (p = 0.007), EOA < 2.5 cm2 (p = 0.05), EOA index (EOAI) > 7 cm2/m2 (p < 0.0001) and prosthesis size-body surface area (BSA) index (SI) > 69 mm/m2 (p = 0.007).

Conclusion: Early mortality occurs in neonates and infants with associated lesions, particularly atrioventricular septal defect. Risk factors for mortality include age, NYHA class, and small IOD and EOA. Risk factors for reintervention include age < 6 months, small predicted annulus size, IOD and EOA, IODI > 50 mm/m2, EOAI > 7 cm2/m2 and SI > 69 mm/m2.