Andersons pediatric cardiology 1470

FIG 55.12 Complications of valve replacement (A–B) Bioprosthetic valves that have degenerated (C) Mechanical valve with thrombus that has occluded the orifice Mitral Valve Repair This requires a thorough knowledge of the dynamic functional anatomy of the valve,76 coupled with defining and dealing with the pathologic changes in each of the component parts of the valve The normal MV performs extremely sophisticated functions apart from allowing unimpeded unidirectional flow into the left ventricle These functions include controlling LV function during both systole and diastole Long-axis systolic function is augmented by the presence of intact mitral chordal apparatus During diastole, early ventricular filling is dependent on dilatation of the mitral annulus.77 Attempts at preserving or recreating the dynamism of the MV components is an important objective of reparative procedures Following careful examination of the valve, a tailored approach to deal with each component part, depending on the particular affection, is made The techniques currently available include the following: Dividing commissural fusion (Fig 55.13) FIG 55.13 Severe commissural fusion involving the leaflets and subvalvar apparatus Splitting fused papillary muscles and recreating new pathways in the fused subvalvar apparatus (Fig 55.14) Transesophageal echocardiographic images of a rheumatic valve before (A) and after (B) repair utilizing commissurotomy, splitting, and release of the subvalvar apparatus and peeling of the anterior mitral leaflet FIG 55.14 Inserting artificial polytetrafluoroethylene (PTFE, or Gore Tex) chordae to support flail segments Chordal shortening of elongated chordae Peeling thickened anterior and/or posterior leaflets to improve mobility and increase surface area (see Fig 55.14) Peeling is possible because rheumatic cusp thickening involves the fibrosa while sparing the elastic, which can be left intact with a supporting, thinned out fibrosa on the atrial side (Fig 55.15)