Supra-annular mitral valve replacement in children.

BACKGROUND: Despite improved mitral repair techniques, some children need mitral valve replacement (MVR). Due to small annulus size, supra-annular MVR is useful.

METHODS: From 2003 to 2010, 15 children had 23 supra-annular MVRs. At first supra-annular MVR, median age was 6.5 months (28 days to 47 months); median weight was 5.4 kg (3.3-11.8 kg). Twelve (80%) had prior operations, 8 (53%) had previous mitral repair. Eight had congenital mitral anomalies (4 with Shone's), 5 had atrioventricular septal defects, 1 had endocarditis, and 1 had a repaired anomalous left coronary artery. All primary MVRs used mechanical valves (≤ 17 mm in 9 patients).

RESULTS: There was one early death (93% survival) in an 11-month-old with congenital pulmonary vein stenosis. One intraoperative conversion from annular to supra-annular MVR developed heart block. Three pacemakers were implanted for supraventricular rhythm disturbances. Three children had valve thrombosis early postoperatively treated medically. On follow-up of 4.3 ± 2.8 years, 8 had reoperation including redo MVR in 6 for pannus formation or thrombus (1 had three redo MVRs). At redo, a larger valve was used in 5 and a bioprosthetic valve in 4 patients. There was one late death after third redo MVR with pulmonary vein stenosis relief (overall survival 87%).

CONCLUSIONS: Supra-annular MVR is useful for children with a small annulus. Operative survival is good with infrequent heart block. Complications are common, including redo MVR and need for left ventricular outflow tract obstruction relief. Pulmonary vein stenosis is a marker for poor outcome; all patients without pulmonary vein stenosis survive long term.