Andersons pediatric cardiology 955
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Introduction:Evaluationand
Management
TOF/PAisanuncommonandhighlyvariableformofcongenitalheartdisease,
bothanatomically,asdiscussedearlier,andclinically.Themostsevereformsof
thisconditionincludepulmonarybloodsupplythroughmajorsystemic-topulmonary(aortopulmonary)collateralarteries(TOF/PA/MAPCAs).Aswithall
duct-dependentlesions,patientswithTOF/PAandpulmonarybloodflow
exclusivelythroughanarterialductrequireearlyinitiationofprostaglandins.In
patientswithTOF/PA/MAPCAs,inwhichpulmonarybloodflowisnot
completelyduct-dependent,prostaglandintherapyisnotnecessarybutlong-term
survivalisneverthelesspoorwithouttreatment,with10-yearand20-year
survivalestimatedat50%and20%,respectively.11,12Asdetailedearlier,the
primarysourceofcomplexityandheterogeneityinpatientswithTOF/PAisthe
pulmonaryarterialcirculation.13,14Theextentandvariabilityofabnormalitiesin
thepulmonarycirculation,alongwiththerelativerarityofthecondition,pose
considerablechallengesforevaluationandmanagement.
AnumberofinvestigatorshavedescribedapproachestotreatmentforTOF
withMAPCAs,butmostserieshavebeenrelativelysmall,havereportedonly
short-termoutcomes,andtheresultshavebeenmixed.15–36Approximately25
yearsago,ourgroupdevelopedamanagementprotocolaimedatoptimally
addressingallofthemorphologicandphysiologicvariantsofthislesionwiththe
goalofachievingcompleterepairinasmanypatientsaspossibleandwith
pulmonaryarterypressuresasclosetonormalaspossible.Important
componentsofthisapproachincludeearlysurgicalunifocalizationindependent
ofsymptomstatus,incorporationofbloodsupplytoalllungsegmentsinthe
unifocalizationprocess,utilizationofnativetissuesforpulmonaryarterial
reconstructionwheneverpossible,andreliefofpulmonaryarterialobstructions
outtothesegmentallevel.Theearlyexperiencewiththisapproachwasfirst
describedin1995,37andtheinitial6-yearexperiencewasreportedin2000.38
Additionalstudiesfromourgrouphavefocusedontherefinementofthis
strategyorspecificissuesorsubpopulationswithinthiscohort.39–45Some
groupshaveadoptedthisapproach16,17,22,26,35,36whileotherscontinuetoutilize
approachesdevelopedpriorto1992,whichareoftenstagedandutilizeavariety
oftechniques,includingplacementofsystemic-to-pulmonaryarterialshuntsor
rightventricle-to-pulmonaryarteryconduits,catheter-basedangioplastyor
stenting,anddifferenttechniquesofunifocalizationthatareoftenpartialor
staged.Althoughthereissomedebateaboutsurgicalstrategies,inthischapter
wewillfocusonourapproachtothemanagementofTOF/PA/MAPCAs.
DiagnosisandEvaluation
Inthecurrentera,mostpatientswithTOF/PAarediagnosedprenatallyorearly
inlife.46,47Clinically,distinguishingTOF/PA/MAPCAsfromTOF/PAortruncus
arteriosusdependsprimarilyonthemorphologyofthecentralpulmonary
arteries,presenceofapatentductusarteriosus,andthedetectionofMAPCAs.
Neonatalpresentationcanvarydependingontheamountofpulmonaryblood
flowandthedegreeofcyanosis,ifany,butittypicallyconsistsofcyanosiswith
amurmur,oftenacontinuousmurmurbestheardintheperipheralchest
producedbyflowthroughMAPCAs.Somepatientswithoutcyanosisinitially
manifestsymptomsofpulmonaryovercirculationandcongestion.Rarely,
patientsmaypresentatmonthsoryearsofagewithprogressivecyanosis.
Imagingevaluationincludesstandardtransthoracicechocardiographyaswellas
modalitiesthatprovidemoredetailedinformationaboutthepulmonaryblood
supply,suchascatheterizationangiography,computedtomography,andinsome
situationsmagneticresonanceimaging.
Echocardiography
TransthoracicechocardiographydemonstratestheusualfindingsofTOF/PA,
withalargeventricularseptaldefectandanoverridingaorta(Fig.36.10).In
patientswithTOF/PAbutnoMAPCAs,echocardiographyisusuallysufficient
forpreinterventionevaluation.InpatientswithTOF/PA/MAPCAs,central
pulmonaryarteriesmayormaynotbevisualizedbyechocardiography,and
MAPCAsarisingfromthedescendingaortaaretypicallyseenbutnotfully
characterized.Inthesmallsubsetofpatientswithasolesupplyofonebranch
pulmonaryarterythroughaductusarteriosusoranomalouspulmonaryartery
fromtheascendingaorta,echocardiographycanbediagnostic.Otherwise,
however,echocardiographydoesnotprovidedetailedinformationregardingthe
anatomyofMAPCAs.Inpatientswithconfluentcentralpulmonaryarteries,it
hasbeenreportedthatthesizeofthecentralpulmonaryarterieson
echocardiographycanhelptodifferentiatepatientswithTOF/PAwhodoanddo
nothaveimportantMAPCAs,48althoughthisassociationgenerallydoesnot
guideevaluation.Thus,inordertocharacterizetheanatomyofthepulmonary
circulationcompletelyinpatientswithMAPCAs,anotherimagingmodalityis
required.
FIG.36.10 Echocardiographicimagesdemonstratingtypicalintracardiac
anatomyinpatientswithtetralogyofFallot/pulmonaryatresia/major
aortopulmonarycollateralarteriesfromthesubcostal(A)andleft
parasternal(B)views,withalargeventricularseptaldefectandan
overridingaorta(Ao).LV,Leftventricle;RV,rightventricle.
ComputedTomographyAngiographyand
MagneticResonanceImaging
Althoughcardiaccatheterizationwithdirectangiographyisthegoldstandard,it
hasbeenourpracticemorerecentlytoobtainacomputedtomography
angiogramtodelineatetheanatomyofthepulmonaryarteriesandMAPCAsin
newborns(Fig.36.11)aswellastheanatomyoftheupperandlowerairways.
Othergroupshavealsoreportedthatahigh-qualitycomputedtomography
