Andersons pediatric cardiology 1467

PercutaneousStrategiesforMitraland
AorticValveDisease
PercutaneousManagementofMitralStenosis
Percutaneousmitralballoonvalvuloplasty(PMBV)hasevolvedastheprocedure
ofchoicefortreatingsevereMSinpatientswithsuitableanatomy.Mid-and
long-termresultsarecomparabletoopencommissurotomy,withtheadvantage
ofbeingalessinvasivetechnique.Aswithotherstructuralandvalvar
interventions,outcomesareheavilydependentonproperpatientselectionand
operatorexperience.

IndicationsforPercutaneousMitralBalloon
Valvuloplasty
PMBViscurrentlyindicatedinsymptomaticpatientswithfavorableanatomy
andanMVareaoflessthan1.5cm2oranindexedareaoflessthan0.6cm2/m2.
PMBVmayalsobeconsideredinasymptomaticpatientswithverysevereMS
(mitralvalvearea<1cm2).Itisworthnotingthatthe2014ACC/AHAguidelines
forthemanagementofvalvarheartdiseaseprovideastagingsystemforMS
wherethegradingofseverityhasbeenrevisedandgradientsacrossthevalveare
nolongerusedtodefineseverity,givenitsstrongdependenceonheartrateand
loadingconditions.39

PatientSelection
PatientsindicatedforPMBVrequirecarefulevaluationtodeterminesuitability
fortheprocedure.“Splitability”ofthevalveatthecommissures—andhence
suitabilityforpercutaneousvalvotomy—isclassicallydeterminedbytheWilkins
echocardiographicscore,whichanalyzesfourkeycomponents:leaflet
thickening,leafletmobility,calcification,andinvolvementofthesubvalvar
apparatus(Table55.2).Eachcomponentisgivenascoreof0to4,witha
maximumscoreof16.Patientswithscoresupto8haveanincreasedlikelihood
ofasuccessfulprocedureaswellasbetterintermediateandlong-term
outcomes.62TheWilkinsscoreis,however,pooratpredictingprocedure-related

MR,whichrequiresevaluationofotherfeaturesincludingheterogeneityof
leafletinvolvement,commissuralcalcification(unicommissuralor
bicommissural),andthepattern/severityofsubvalvarinvolvement.63,64
Table55.2
GradingofMitralValveCharacteristicsFromEchocardiographic
ExaminationUsingtheWilkinsScore
Grade Mobility
1
Highlymobilevalve
withonlyleaflettips
restricted
2
Leafletmidandbased
portionshavenormal
mobility
3

4

SubvalvarThickening
LeafletThickening
Calcification
Minimalthickeningjustbelowthe Leafletsnearnormal Asingleareaof
MVleaflets
inthickness(4–5mm) increasedecho
brightness
Thickeningofchordalstructures
Midleafletsnormal,

Scatteredareasof
extendinguptoone-thirdofthe
considerable
brightnessconfined
chordallength
thickeningofmargins totheleaflet
(5–8mm)
margins
Valvecontinuesto
Thickeningextendingtothedistal Thickeningextending Brightness
moveforwardin
thirdofthechords
throughtheentire
extendingintothe
diastole,mainlyfrom
leaflet(5–8mm)
midportionofthe
thebase
leaflets
Noorminimal
Extensivethickeningand
Considerable
Extensive
forwardmovementof shorteningofallchordalstructures thickeningofall
brightness
theleafletsindiastole extendingdowntothepapillary
leaflettissue(>8to10 throughoutmuchof
muscles
mm)
theleaflettissue

MV,Mitralvalve.
ModifiedfromWilkinsGT,WeymanAE,AbascalVM,etal.Percutaneousballoondilatationofthe
mitralvalve:ananalysisofechocardiographicvariablesrelatedtooutcomeandthemechanismof
dilatation.BrHeartJ.1988;60(4):299–308.

Allpatientsmustundergotransesophagealechocardiography(TEE)priorto
theproceduretoruleoutthepresenceofaleftatrialorleftatrialappendage
thrombus.TEEmayalsobeusefulinpatientswithpoortransthoracicwindows.

ContraindicationstoPercutaneousMitral
BalloonValvuloplasty
AbsolutecontraindicationstoPMBVincludemoderateorsevereMR,the
presenceofaleftatrialthrombus(free-floatingoradherenttotheinteratrial
septum),bicommissuralcalcification,andtheneedforsurgeryonanothervalve.
Thepresenceofaleftatrialappendagethrombuswarrantsanticoagulationfor3
monthsfollowedbyreevaluationbyTEE.Persistenceofaleftatrialappendage
thrombushastraditionallybeenregardedasacontraindicationtotheprocedure;


however,afewreportssuggestthatPMBVcansafelybeperformedbyhighly
experiencedoperatorsinpatientswithadherentorganizedthrombilimitedtothe
leftatrialappendage.65,66

MechanismofPercutaneousMitralBalloon
ValvuloplastyandTechnicalConsiderations
ThreemainmodalitiescurrentlyexistforpercutaneousmanagementofMS,all
ofwhichdependonsplittingofthecommissures.Theprocedureisconsidered
successfulwhenthepostvalvotomyvalveareaincreasestomorethan1cm2/m2.
ThemostcommonlyusedistheInouetechnique,firstintroducedbyKanji

Inouein1982.67ThestandardInouetechniquedependsonantegradeaccessinto
theMVorificeviaatransseptalpuncture.Retrograde(transaortic)accesshas
beenreportedinalimitednumberofcasesbutisrarelyusedtoday.Theballoon
ismanufacturedfromtwolatexlayersbetweenwhichisapolyestermicromesh.
Anextralatexbandisplacedaroundthecenteroftheballoon;astainlesssteel
tubeisusedtostretchtheballoonpriortoinsertionanda14-Frtapereddilator
thenenlargestheinteratrialopening.Owingtothedifferentelasticpropertiesof
theproximal,distal,andcentralpartsoftheballoon,itexhibitsfourdifferent
inflationstages,whichenablesnugfittingacrossthevalvebeforegradual
dilatation(Fig.55.11).