Long-term surgical outcome of mitral valve repair in infants and children with Shone's anomaly.

OBJECTIVES: Having assembled information on a large series of patients with Shone's anomaly with the longest follow-up, we studied the operative results and long-term outcome of mitral valve (MV) repair techniques performed to correct the left ventricular inflow tract lesions of this congenital anomaly.

METHODS: Between 1986 and 2011, 45 infants and children [mean age 5.16 ± 5.0 (median 3.9; range 2 months to 16.8 years] underwent surgical correction of Shone's anomaly. Left ventricular outflow tract obstructive lesions consisted of coarctation of the aorta, found in 89%, subaortic stenosis due to fibromuscular hypertrophy in 71% and subvalvular membrane in 51%. Left ventricular inflow tract obstructions concentrated on the mitral valve included mitral ring in all cases and the gamut of small and narrowed mitral orifice, commissural fusion, dysplastic or thickened leaflets, shortened and fused chordae, fibrous obliteration of interchordal spaces, underdeveloped papillary muscles, parachute valve, and supravalvular mitral ring-all contributing to mitral stenosis.

RESULTS: MV repair was performed using commissurotomy, division of chordae tendinae, papillary muscle splitting and fenestration, and resection of mitral ring, applied according to the presenting morphology in patients with either previously-corrected or concomitant correction of the left-sided obstructive lesions. Postoperative echocardiography showed absence of MV stenosis and immediate improvement of symptoms, except in a 3-month-old infant who died 18 days postoperatively due to myocardial failure. During the 23-year follow-up, 23 patients underwent repeat MV repair and one underwent MV replacement after failed attempts at repair. Mean duration of follow-up was 17.5 ± 1.5 years (range 6.4-22.7 years). Freedom from reoperation was 97.6 ± 2.4%, 89.3 ± 5.1%, 77.1 ± 7.2%, 72.0 ± 8.3% and 52.8 ± 11.8%, at 30 days, 1, 5, 10 and 15 years postoperatively, respectively Cumulative survival rate was 97.6 ± 2.4%, 92.3 ± 4.3%, 83.8 ± 6.1%, 75.7 ± 7.8% and 70.3 ± 8.9%, at 30 days, 1, 5, 10 and 15 years postoperatively, respectively. Mortality unrelated to valve repair accounted for nine deaths (20%). Age at operation, severity of mitral abnormalities and concomitant left ventricular outflow tract lesions proved to be independent risk factors for reoperation and mortality (P < 0.05).

CONCLUSIONS: Long-term functional outcome of mitral valve repair in children with Shone's anomaly is satisfactory. Repeat MV repair and/or replacement may be deemed necessary during the course of follow-up.