Andersons pediatric cardiology 1263
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FIG.47.12 Magneticresonanceangiogramsshowingthattheseverely
hypoplasticcervicalaorticarch,left-sidedinthisinstance,reachestothe
lowerneck.Itshowsnormalbranching.Interruptionoftheaorticarchhas
beensuspectedinthispatient,whichcouldnotbeexcludedat
echocardiography.LCCA,Leftcommoncarotidartery;LSA,leftsubclavian
artery;RIA,rightinnominateartery.
Isolatedoriginofthesubclavianarteryfromthepulmonaryarterythroughthe
arterialductisararetypeofanomalyinwhichthesubclavianarteryis
disconnectedfromtheaorta,insteadtakingitsoriginfromthepulmonaryartery
onthatsidethroughthepersistentlypatentarterialduct(Fig.47.13A–B).39–41It
isexplainedonthebasisofabnormalregressionattwolocationsinthe
hypotheticaldoublearch,oneproximalandtheotherdistaltotheoriginofthe
affectedsubclavianartery.Suchisolationoccursmorecommonlywhenthe
aorticarchisrightsided,withtheleftsubclavianarterybeingtheisolatedartery
inthemajorityofcases.Flowtotheisolatedarteryvariesaccordingtothesize
ofthepersistentlypatentarterialductandthepatencyofthepulmonaryoutflow
tract.Whenthearterialductiswideopenandthereisnoobstructionatthe
infundibularlevel,theleftsubclavianarteryissuppliedthroughthepulmonary
arteries.Ifassociatedwithsignificantpulmonaryobstruction,theflowthrough
thearterialductmaybereversed.Postnatally,whenthearterialductcloses,the
anomalousarterymayloseitsprimarysupplyofbloodandcanresultin
vertebralstealonthesideoftheisolatedartery.Brachiocephalicorcarotid
arteriescanalsobeisolatedincomparablefashion.42
FIG.47.13 (A)Hypotheticalmodelforthedoublearchusedtoexplain
isolatedoriginoftheleftsubclavianartery(LSA)fromtheleftpulmonary
artery(LPA)throughtheleftarterialduct(left).Theredbarsshow
regressionoftheleftaorticarch(LAA)intwolocations,bothproximaland
distaltotheoriginoftheLSA.Asthedistalinterruptionisdistaltothe
insertionoftheleftarterialduct,theLSAbecomesisolatedfromtheaortic
arch,insteadretainingitsconnectionwiththeLPA.Therightarterialduct
alsopersists.Themiddleandrightpanelsshowthearrangementsinthe
fetalandpostnatalcirculations.(B)Contrast-enhancedmagnetic
resonanceangiogramsreformattedinrightanterioroblique(left),left
anterioroblique(middle),andfrontal(right)planesshowingarightaortic
arch(RAA)thatgivesrisetotheleftcommoncarotidartery(LCCA),right
commoncarotidartery(RCCA),andrightsubclavianartery(RSA)in
sequence.TheLSAarisesfromtheproximalLPAthroughtheleft-sided
arterialduct.Therightarterialductispatentbetweentherightpulmonary
artery(RPA)andthedescendingaorta.Notethattherightarterialducthas
anampullarydilatation(asterisk)atitspulmonaryarterialend.LVA,Left
vertebralartery;MPA,mainpulmonaryartery;RPA,rightpulmonaryartery;
RVA,rightvertebralartery.(FromSunAM,AlhabshanF,BransonH,etal.
MRIdiagnosisofisolatedoriginoftheleftsubclavianarteryfromtheleft
pulmonaryartery.PediatrRadiol.2005;35:1259–1262.)
Double-barreled,ordoublelumen,aortaisarareanomalyinwhichthe
ascendinganddescendingcomponentsoftheaortaareconnectedbytwoaortic
archesonthesamesideofthetrachea(Fig.47.14).42–44Itshouldnotbe
confusedwiththedoubleaorticarch,inwhicheacharchistotheoppositesides
ofthetrachea.Inthepast,thisanomalyhasbeeninterpretedaspersistenceofthe
embryologicfifthaorticarch.43However,theexistenceofthefifthaorticarchin
humanandmammalianembryosremainscontroversial,neverhavingbeen
encounteredduringnormaldevelopment.45
FIG.47.14 Computedtomogramsshowingadouble-barreledaorticarch
inapatientwithtetralogyofFallotandpulmonaryatresia.LPA,Left
pulmonaryartery.(FromBernasconiA,GooHW,YooSJ.Double-barrelled
aortawithtetralogyofFallotandpulmonaryatresia.CardiolYoung
2006;17:98–101.)
