Andersons pediatric cardiology 434

FIG.18.4 Retrogradeaorticballoonvalvoplastywithrapidrightventricular
pacingasseeninfrontalprojection.


FIG.18.5 Anterogradeballoonaorticvalvoplasty.Theballoonis
introducedthroughthefemoralveinandacrosstheovalfossadefect,or
afteratransseptalpuncture,toaccesstheleftheart.Thewireisplacedin
thedescendingaortaandprovidesstabilitytotheballoon.

Recentreportsoflong-termoutcomeafteraorticballoonvalvoplastyindicate
thatthereisanexcellentearlyreliefofthevalvargradientbutanincreasein
aorticregurgitation.96Independentpredictorsofunfavorableoutcomehavebeen
asmallaorticroot,poorfunctionoftheleftventricleormitralvalve,andlimited
experienceoftheoperator.97Valvarmorphologyhasrecentlybeendemonstrated
torelatetovalvarfunctionfollowingvalvuloplasty,withfunctionallyunicuspid
valvesandothersubtypeswithgreaterleafletfusiondemonstratingbetter
responsetoballoondilation.98Procedure-relatedmortalityisreportedat4.8%
andishighestincriticalAS.97Althoughtheriskofvascularinjuryishigh,the
majorityofthecomplicationsaretransientandrespondtothrombolysisand
anticoagulation.Incriticalaorticstenosis,themorphologyoftheaorticroot,the
mitralvalveandpresenceofleftventricularendocardialfibroelastosishavea
majorimpactonoutcomeandneedforreintervention.Neonatalcriticalaortic
stenosisremainschallengingdespitecontinuingdevelopmentofcatheter
technologyforsmallbabies.Despiteeffectivereliefofstenosis,patientsmay


requirefunctionallyuniventricularpalliationifthemorphologyisnotfavorable
foreffectivebiventricularcirculationsoriftheventricularmyocardiumremains
dysfunctional(seealsoChapter44).
ImplantationoftheAorticValve.
Percutaneousinterventionsontheaorticvalveinadultswithcalcificaortic

valvarstenosisandothercomorbiditiesrenderingthevalveinoperableare
encouraging.Thefirstreportofinsertionofbovinepericardialtrifoliatevalve
camefromCribierandcolleagues.99Proceduralcomplicationsinearly
implantationswererelatedtotheanterogradeapproachandthelargesizeofthe
systemrequiredfordelivery.Thetechniquehasbeenrefined,withdevelopment
ofaretrogradeapproach,andimplantationofthevalvewithrapidright
ventricularpacingtoreducetheriskofembolization.20Self-expandingstentmountedvalveshavealsobeenusedinsimilarclinicalsettings.100However,the
currentdevicesavailablearenotyetsuitableforroutineuseinchildrenand
youngadults,althoughoccasionalimplantshaveoccurred.101

MitralValve
MitralStenosis.
Congenitalmitralvalvarstenosisisacomplexdisease,withinvolvementof
supravalvar,valvar,andsubvalvarcomponents(seeChapter34).Balloon
dilationisrarelyusedasfirstintervention,duetothehighriskofrestenosisor
riskofinjurytothevalvartensionapparatusandleaflets,leadingtosevere
regurgitation.However,percutaneousvalvoplastyhassuccessfullyreplaced
closedandopenmitralcommissurotomyforrheumaticmitralstenosis.Selection
ofpatientsbasedonechocardiographyisfundamentalinpredictingoutcomes
andrequiresadetailedassessmentofthemitralvalve.102
Theapproachisanterogradeaftertransseptalpuncture.TheInoueballoonis
mostwidelyused,whichconsistsofacoaxialballoonwithadoublelumen.
Inflationleadstosequentialdilationofthedistalpart,facilitatingentryintothe
leftventricle,oftheproximalpartfixingtheballoonacrossthemitralvalve,and
ofthecentralpart,whichdilatesthevalvarannulus.AMultitracktechniquewith
amonorailsystemwithtwoballoonsoverasingleguidewirewasintroducedby
Bonhoefferandcolleagues,46permittingsuccessfuldilationofthefusedleaflets
ofthemitralvalve.