Repair strategies in hammock and parachute mitral valves in infants and children

Purpose: Parachute and hammock valves in children remain the most challenging congenital malformations to correct. We report our institutional experience with valve-preserving and remodeling techniques and the long-term outcome in infants and children.

Methods: Between 1992 and March 31, 2011, 12 children, median age 9 months (range 1 month-14 years), underwent mitral valve (MV) repair at our institution. Six (50%) belonged to age group<1 year. Eight (median age 6 months) had hammock valves and 4 (median age 1 year) had parachute valves. Seven had class IV mitral insufficiency (MI) and 5 had class III MI. All had moderate mitral stenosis.

Results: Intraoperative findings included dysplastic and shortened chordae, absence of papillary muscles with fused and thickened commissures in children with hammock valves (HV) and annular dilatation. Those with parachute valves (PV) had fused and shortened chordae with single papillary muscles. MV repair was performed using annuloplasty, commissurotomy, modified Gerbode-Hetzer plication plasty and papillary muscle splitting, applied according to the presenting morphology. Postoperative echocardiography showed absent to minimal MI, except in a 1-month-old infant whose MI was progressive and who underwent MV replacement using a 14-mm biological prosthesis but died 1 week postoperatively. Another 4-month-old infant underwent repeat MV reconstruction 1 month after the initial repair, but severe MI persisted; hence he underwent replacement with mechanical valve 2 weeks later and survived. During the 19-year follow-up, 5 patients with HV and one with PV underwent repeat MV reconstruction. A 7-month-old infant died of unknown cause 5 years after the initial repair. Freedom from reoperation was 50% and survival rate was 83.4%. Age <1 year proved to be a high risk factor for reoperation and mortality (p=0.00).

Conclusions: In children with parachute and hammock valves, surgical repair offers satisfactory functional outcome during long-term follow-up. Repeat MV repair may be necessary during the course.