Andersons pediatric cardiology 1260
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FIG.47.4 (A)Modeofformationofarightaorticarch(RAA)withaberrant
originoftheleftsubclavianartery(LSA)andaleft-sidedarterialduct.Inthis
andthesubsequentpanelsformattedinthisfashion,thehypothetical
modelofthedoublearchisshownatleft,withtheredbarsindicatingthe
segmentsthatwillregress.Themiddlediagramshowsthesituationinthe
fetalcirculation.Inthisvariant,theRAA,alongwiththeremnantofthe
distalleftaorticarch(LAA),theleft-sidedarterialduct,andthepulmonary
trunk(PT),produceaU-shapedvascularlooparoundthetracheaand
esophagus.AsthetwolimbsoftheU-shapedloopareattachedtothe
heart,thisproducesacompletevascularring.Inthepostnatalcirculation,
shownatright,consequenttoclosureofthearterialduct,theproximalpart
oftheaberrantLSA,representingthedistalremnantoftheLAA,usually
persistsastheso-calleddiverticulumofKommerell.Notethattheflowof
bloodinthisdistalremnantoftheLAAreversesdirectionafterbirth.(B)
FetalechocardiogramsillustratingthesituationdiagrammedinFig.47.6
showaU-shapedvascularlooparoundthetrachea.Notetheextentofthe
gapbetweentheascendingaortaandthePT.(C)Computedtomograms
showinganRAAwithanaberrantLSAarisingfromadiverticulumof
Kommerell.Atright,theexpectedlocationoftheligamentousarterialduct
ismarkedwitharedbar.Notethemildcompressionofthedistaltrachea.
LCCA,Leftcommoncarotidartery;LPA,leftpulmonaryartery;MPA,main
pulmonaryartery;RCCA,rightcommoncarotidartery;RPA,right
pulmonaryartery;RSA,rightsubclavianartery;SCV,superiorcavalvein.
FIG.47.5 (A)Modeofformationofrightaorticarch(RAA)withaberrant
leftsubclavianartery(LSA)andright-sidedarterialduct.Inthefetaland
postnatalcirculations,thisarrangementproducesavascularslingonthe
rightsideofthetracheaandesophagus.Thisisararecombination.(B)
ThesecomputedtomogramsshowanRAAwithaberrantoriginoftheLSA
butnoarterialductinanewbornwithtetralogyofFallotandpulmonary
atresia.Thecomputedtomogramsinaxialandcoronalplanesshowthat
theRAAgivesrisetotheaberrantLSAwithnointerveningdiverticulumof
Kommerell.Thepulmonaryarterieswerenonconfluent,withthepulmonary
circulationsuppliedbymajoraortopulmonarycollateralarteries(MAPCA),
withcongenitalabsenceofbotharterialducts.LAA,Leftaorticarch;LCCA,
leftcommoncarotidartery;LPA,leftpulmonaryartery;MPA,main
pulmonaryartery;RCCA,rightcommoncarotidartery;RPA,right
pulmonaryartery;RSA,rightsubclavianartery;SCV,superiorcavalvein.
Leftaorticarchwithaberrantrightsubclavianarteryisthemostcommon
anomalyinvolvingtheaorticarchbutisusuallyasymptomatic.1,2,24,27,28It
resultsfromabnormalregressionoftherightarchbetweentheoriginsofthe
rightcommoncarotidandrightsubclavianarteries,leavingtherightsubclavian
arteryattachedtothedistalremnantoftheright-sidedaorticarch(Fig.47.6A
andB).Asaconsequence,thedistalremnantoftherightaorticarchandthe
rightsubclavianarterytogetherconstitutetheaberrantsegments.Inmostcases,
itistheleftarterialductthatpersists.Thiscombinationformsapartialvascular
ringaroundtheleftsideofthetracheaandesophagus.Typically,theaberrant
rightsubclavianarterycoursesbehindtheesophagusbuthasbeendescribedto
coursebetweenthetracheaandesophagus,althoughagainthesevesselsmay
havebeencollateralarteries.1,2Whenthereisaright-sidedarterialductbetween
theaberrantarteryandtherightpulmonaryartery,thereisacompletevascular
ring(Fig.47.7).Theringconsistsoftheascendingaorta,leftaorticarch,
descendingaorta,distalremnantoftherightaorticarch,rightarterialduct,right
pulmonaryartery,andpulmonarytrunk,withtheheartitselfcompletingthering.
Infetallife,whenthearterialductisawidechannelthatconnectsthepulmonary
arterytothedescendingaorta,anL-shapedloopisformedaroundthetrachea
andesophagus.Withclosureoftheright-sidedarterialductafterbirth,thedistal
remnantoftherightaorticarchpersistsasthediverticulumofKommerell.Itis
theoreticallypossibleforaleft-sidedaorticarchtobeassociatedwithaberrant
originoftherightbrachiocephalicartery.Asfarasweareaware,thishasnot
beenreported.Aberrantsubclavianorbrachiocephalicarteriescoexistingwith
eitherright-sidedorleft-sidedaorticarchesareoftenassociatedwithother
anomalies,includingacommoncarotidarterialtrunk,anomalousoriginofthe
vertebralarteryfromthecommoncarotidarteryonthesameside,anomalous
pointofentranceofthevertebralarteryintothecervicalspine,andanabnormal
drainagesiteofthethoracicduct.16Althoughtheseanomaliesareclinically
silent,theymaybeofpracticalimportancetothesurgeon.
