Repair for Congenital Mitral Valve Stenosis

We report the techniques and long-term outcome of mitral valve (MV) repair to correct congenital mitral stenosis in children. Between 1986 and 2014, 137 children (mean age 4.1 ± 5.0, range 1 month-16.8 years) underwent repair of congenital mitral stenosis (CMS). In 48 patients, CMS is involved in Shone's anomaly. The typical congenital MS (type I) was seen in 56 patients. Hypoplastic MV (type II, n = 15) was associated with severe left ventricular outflow tract abnormalities and hypoplastic left ventricular cavity and muscle mass. Supravalvar ring (type III, n = 48) ranged from a thin membrane to a thick discrete fibrous ridge. Parachute MV (type IV, n = 10) have 2 leaflets and barely distinguishable commissures, but all chordae merged either into 1 major papillary muscle or asymmetric papillary muscles-1 dominant and the other minuscule. Hammock valve (type IV, n = 8) appeared dysplastic with shortened chordae directly inserted into the posterior left ventricular muscle mass. MV repair was performed using commissurotomy, chordal division, papillary muscle splitting and fenestration, and mitral ring resection, each applied according to the presenting morphology. During the 28-year follow-up period, 23 patients underwent repeat MV repair and 3 underwent MV replacement after failed attempts at repeat repair. At 1 and 15 years postoperatively, freedom from reoperation was 89.3 ± 5.1% and 52.8 ± 11.8%, and cumulative survival rates were 92.3 ± 4.3% and 70.3 ± 8.9, respectively. Mortality unrelated to repair accounted for 9 (20%) deaths. Long-term functional outcome of MV repair in children with CMS is satisfactory. Repeat repair or replacement may be deemed necessary during the course of follow-up.