Andersons pediatric cardiology 1470
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FIG.55.12 Complicationsofvalvereplacement.(A–B)Bioprosthetic
valvesthathavedegenerated.(C)Mechanicalvalvewiththrombusthathas
occludedtheorifice.
MitralValveRepair
Thisrequiresathoroughknowledgeofthedynamicfunctionalanatomyofthe
valve,76coupledwithdefininganddealingwiththepathologicchangesineach
ofthecomponentpartsofthevalve.ThenormalMVperformsextremely
sophisticatedfunctionsapartfromallowingunimpededunidirectionalflowinto
theleftventricle.ThesefunctionsincludecontrollingLVfunctionduringboth
systoleanddiastole.Long-axissystolicfunctionisaugmentedbythepresenceof
intactmitralchordalapparatus.Duringdiastole,earlyventricularfillingis
dependentondilatationofthemitralannulus.77Attemptsatpreservingor
recreatingthedynamismoftheMVcomponentsisanimportantobjectiveof
reparativeprocedures.Followingcarefulexaminationofthevalve,atailored
approachtodealwitheachcomponentpart,dependingontheparticular
affection,ismade.Thetechniquescurrentlyavailableincludethefollowing:
1.Dividingcommissuralfusion(Fig.55.13).
FIG.55.13
Severecommissuralfusioninvolvingtheleafletsand
subvalvarapparatus.
2.Splittingfusedpapillarymusclesandrecreatingnewpathwaysinthe
fusedsubvalvarapparatus(Fig.55.14).
Transesophagealechocardiographicimagesofa
rheumaticvalvebefore(A)andafter(B)repairutilizing
commissurotomy,splitting,andreleaseofthesubvalvar
apparatusandpeelingoftheanteriormitralleaflet.
FIG.55.14
3.Insertingartificialpolytetrafluoroethylene(PTFE,orGoreTex)chordae
tosupportflailsegments.
4.Chordalshorteningofelongatedchordae.
5.Peelingthickenedanteriorand/orposteriorleafletstoimprovemobility
andincreasesurfacearea(seeFig.55.14).Peelingispossiblebecause
rheumaticcuspthickeninginvolvesthefibrosawhilesparingtheelastic,
whichcanbeleftintactwithasupporting,thinnedoutfibrosaonthe
atrialside(Fig.55.15).
