Andersons pediatric cardiology 960
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22q11deletionwhoarescheduledtoundergounifocalizationsurgeryduring
infancyareconsideredforamodifiedbariumswallowstudytoscreenforsilent
pulmonaryaspiration,andfeedingismodifiedbasedontheresults.
Becausechildrenundergoingunifocalizationareatriskforprolonged
respiratoryfailureanddeconditioning,theybenefitfromgoodnutritionalstatus
priortosurgery,whichlikelyimprovestheirabilitytorecoverfromprolonged
mechanicalventilation.Accordingly,itisimportanttoscreenpreoperativelyfor
malnutritionandintervenetoimproveweightgainforunderweightchildren.The
valueofgoodnutritionalstatuscanbeappreciated,forexample,inpatientswho
developphrenicnerveinjury.Extensivesurgicaldissectioncanresultinphrenic
nerveinjury,andpatientsmaydemonstrateweaknessorparalysisofthe
correspondingdiaphragmaftersurgery.Althoughthisisnotacommon
postoperativecomplication,goodbaselinestrengthandnutritioncanfacilitatean
expeditiousrecovery.
Management
ManagementStrategy
InpatientswithTOF/PAandaductussupplyingconfluentcentralpulmonary
arteries,themostcommonapproachtomanagementisinitialstabilizationwitha
prostaglandininfusionfollowedbycompleteneonatalrepair,consistingof
ventricularseptaldefectclosurewithapatchandplacementofavalvedright
ventricle-to-pulmonaryarteryconduit.Insomehigherriskpatients,particularly
thosewithrelativelyhypoplasticbranchpulmonaryarteries,someclinicianswill
optforaninitialpalliativeprocedure,suchasasystemic-to-pulmonaryarterial
shunt,ductalstent,orperforationoftheatreticpulmonaryvalveandplacement
ofastentacrosstherightventricularoutflowtract.Theseapproachesare
relativelystandard,andfewsurgicalstudiesarededicatedtothissimplerformof
TOF/PA(i.e.,withoutMAPCAs),sotherearelimitedcontemporarydataonthe
breakdownofmanagementstrategiesandoutcomes.Rather,itisthemore
complexformsofTOF/PA/MAPCAsthatposethegreatestdifficulty;therefore
thefollowingsectionsarefocusedonthislesion.
Asinitiallydescribedin199537andrefinedovertime,ourprogrammatic
managementalgorithmforTOF/PA/MAPCAsaimsforearlycomplete
unifocalizationandintracardiacrepairincorporatingalllungsegments,with
augmentationofpulmonaryarterybranches(whethernativepulmonaryarteries
orMAPCAs)downtothesegmentallevel.Althoughpatientsmaycometo
attentionindifferentcircumstancesandatvaryingages,theidealstateisto
evaluatethepatientinthenewbornperiodandformulateastrategybasedonthe
clinicalstatusandtheanatomyofthepulmonarycirculation,asoutlinedinFig.
36.16.
FIG.36.16 Decisiontreefordeterminingtreatmentandtimingfor
newbornswithtetralogyofFallot(TOF)/pulmonaryatresia(PA)/major
aortopulmonarycollateralarteries(MAPCAs).*Patientswithonepulmonary
arterysuppliedbyapatentductusarteriosus(PDA)oranomalousPAfrom
theascendingaorta,whohaveasmallnumberofgood-sizedMAPCAsto
thecontralaterallung,generallyundergoneonatalrepairinsteadof
palliationtoestablishastablecontrolledsourceofpulmonarybloodflow
(Qp).Theflowstudyisusedselectivelyinpatientswithborderline
pulmonaryvasculature.AP,Aortopulmonary;PBF,pulmonarybloodflow;
RV,rightventricle;VSD,ventricularseptaldefect.
Themostcriticalaspectoftheneonatalclinicalevaluationistoestimatethe
overallpulmonarybloodflow,whichisreflectedbythesystemicoxygen
saturation.Patientsarecategorizedashavinghigh,low,orbalancedpulmonary
bloodflow(>90%,<75%,or75%to90%,respectively).Ifthesaturationis75%
to90%,whichisthecaseinmostnewborns,thereisnoclinicalneedfor
neonatalintervention.However,thesourceofpulmonarybloodsupplymustalso
beassessedtoascertainvariantsthatmeritneonatalintervention,inparticular(1)
centrallyconfluentnativepulmonaryarteriesthatarborizetoalllungsegments,
suchthatallMAPCAsaredualsupply,or(2)aunilateralductusarteriosus(or
anomalouspulmonaryarteryfromtheascendingaorta)withMAPCAstothe
otherlung(seeFig.36.15).Intheminorityofneonateswithapersistentsystemic
oxygensaturationeitherlessthan75%orgreaterthan90%,indicatinglowor
highpulmonarybloodflow,respectively,wetypicallyperformsurgerywithin
thefirstmonthortworegardlessoftheanatomyofpulmonarybloodsupply,
withtheoperationdependingontheclinicalandanatomicdetails.
NeonatalManagement(About15%ofPatients)
Dual-supplyMAPCAstoconfluent,normallyarborizingpulmonary
arteries.
Ifthenativepulmonaryarteriesareconfluentandarborizetoalllungsegments
(i.e.,allMAPCAsaredualsupply),regardlessofthesystemicoxygensaturation,
adirectconnectionofthemainpulmonaryarterytotheascendingaorta(i.e.,
surgicalaortopulmonarywindow,Melbourneshunt)iscreatedintheneonatal
periodasacentralshunttopromotegrowthofthenativepulmonaryartery
system,whichisusuallyhypoplastic.Thepatientshouldreturnatapproximately
6monthsofageforfurtherassessmentofpulmonaryarterialgrowth.Becauseall
lungsegmentsareconnectedtothecentralpulmonaryarterialsystem,
unifocalizationofallMAPCAsisgenerallynotnecessaryinthesepatients,
althoughsomeMAPCAsareutilizedtofacilitatepulmonaryarterial
augmentationwithnativetissue.
Unilateralductusoranomalouspulmonaryarteryfromthe
ascendingaorta.
Ifthereisaunilateralductus(eitherpatentorclosed)toonelungandMAPCAs
