Andersons pediatric cardiology 1261
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FIG.47.6 (A)Morphogenesis(left)fetalarrangement(middle)and
postnatalstructureofleftaorticarch(LAA)withaberrantoriginoftheright
subclavianarteryandleft-sidedarterialduct.Inthehypotheticalmodel,the
redbarsagainindicatethesegmentsthatregress.Inthefetaland
postnatalcirculations,avascularslingisformedontheleftsideofthe
tracheaandesophagus.(B)ComputedtomogramsshowanLAAand
aberrantrightsubclavianarteryarisingfromthedescendingaorta,withno
interveningdiverticulumofKommerell.Theposteriorwallofthetrachea
showsashallowindentationfromtheaberrantrightsubclavianartery
(right).LCCA,Leftcommoncarotidartery;LPA,leftpulmonaryartery;LSA,
leftsubclavianartery;MPA,mainpulmonaryartery;RAA,rightaorticarch;
RCCA,rightcommoncarotidartery;RPA,rightpulmonaryartery;RSA,
rightsubclavianartery.
FIG.47.7 Derivationandstructuresofleftaorticarch(LAA)withaberrant
rightsubclavianarterywhenthearterialductisrightsided.Inthe
hypotheticalmodel,theredbarsagainindicatethesegmentsthatregress.
Inthefetalcirculation(middle),theLAA,thedistalremnantoftheright
aorticarch(RAA),theright-sidedarterialduct,andthepulmonarytrunk
produceanL-shapedvascularlooparoundthetracheaandesophagus.
BecausethetwolimbsoftheL-shapedloopareattachedtotheheart,
thereisacompletevascularring.Inthepostnatalcirculation(right),
subsequenttoclosureofthearterialduct,theproximalpartoftheaberrant
rightsubclavianartery,representingthedistalremnantoftheRAA,persists
asadiverticulumofKommerell.Notethat,aswiththeprevioussituation,
theflowinthedistalremnantoftheRAAswitchesitsdirectionafterbirth.
LCCA,Leftcommoncarotidartery;LPA,leftpulmonaryartery;LSA,left
subclavianartery;MPA,mainpulmonaryartery;RCCA,rightcommon
carotidartery;RPA,rightpulmonaryartery;RSA,rightsubclavianartery.
Aright-sidedaorticarchwithamirror-imagebranchingresultsfrom
abnormalregressionoftheleftaorticarchdistaltotheoriginoftheleft
subclavianartery(Fig.47.8AandB).Thisanomalyoftheaorticarchonlyrarely
formsavascularringregardlessofthesidednessofthearterialduct.Inthis
pattern,thepersistingarterialductisusuallyontheleft,connectingthebaseof
theleftbrachiocephalicarterytotheleftpulmonaryartery.29Lesscommonly,the
arterialductiseitherontherightorbilateral.Rarely,thearterialductarisesfrom
thedescendingaortaontherightsideandtakesaretroesophagealcourseto
connecttotheleftpulmonaryartery.3,6,29–32Thisistheonlycombinationthat
constitutesacompletevascularringinthepresenceofmirror-imagebranching.
(Fig.47.9)Theanomalyresultsfromabnormalregressionoftheleftaorticarch
distaltotheoriginoftheleftsubclavianarteryandproximaltotheinsertionof
thepersistingleftarterialduct,withregressionoftherightarterialduct.The
distalleftaorticarchremnantpersistsasadiverticulumofKommerell.
FIG.47.8 (A)Morphogenesis,fetalarrangement,andpostnatalstructure
ofarightaorticarch(RAA)withmirror-imagebranching,theredbarsinthe
hypotheticalmodelindicatingthesegmentsthatregress.Inthemajorityof
cases,itisthearterialductontheleftsidethatpersists,withregressionof
theleftaorticarch(LAA)distaltotheoriginsoftheleftsubclavianartery
(LSA)andtheleftarterialduct,alongwiththeright-sidedarterialduct.In
thepostnatalcirculation,theleft-sidedarterialligamentconnectsthebase
oftheleftbrachiocephalicorsubclavianarterytotheleftpulmonaryartery
(LPA).Persistenceoftheright-sidedarterialductisuncommon.(B)The
computedtomograms,seenfromaboveandthefront,showtheaorticarch
ontherightsideoftrachea.Theaorticarchgivesrisetotheleft
brachiocephalicartery(LBA),rightcommoncarotidartery(RCCA),and
rightsubclavianarteryinsequence.Theexpectedlocationofthe
ligamentousarterialductismarkedbyaredbar(right).NotethattheLSA
kinksinferiorlyandtheLPAismildlystenotic,bothhighlysuggestiveofthe
presenceofaleft-sidedarterialligament.LCCA,Leftcommoncarotid
artery;LIA,leftinnominateartery;MPA,mainpulmonaryartery;RPA,right
pulmonaryartery;RSA,rightsubclavianartery;SCV,superiorcavalvein.
