Andersons pediatric cardiology 1256
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Introduction
Theaorticarch,thearterialduct,andtherightandleftpulmonaryarterieshavea
closespatialrelationshipwiththemajorairwaysandtheesophagus.Duetothis
closeproximity,abnormalitiesinthesize,position,and/orpatternofbranching
patternofthesestructuresmaycauseobstructiontothetrachea,bronchi,or
esophagus.Manyoftheabnormalitiesofpositionandbranching,alongwiththe
so-calledpulmonaryarterialsling,arecharacterizedbyacompleteorpartial
encirclementofthetracheaandesophagus,orthetracheainisolation,bya
compositevascularstructure.Althoughthetermsringandslinghavebeenused
somewhatloosely,weusevascularringtodenoteacompleteencirclementofthe
airwayandesophagus.Incompleteencirclementoftheairwayandesophagus
willbereferredtoasapartialvascularring.Pulmonaryarteryslingisdiscussed
asaseparateentity.Vascularringsandslingsaretheclassicanomaliesthatcause
symptomsandsignsofobstructiontotheairwaysandesophagealcompression.
However,notallringsandslingsresultinclinicallyrecognizablesymptomsand
signs.Conversely,othervascularabnormalitiesdonotformaringorslingand
yetmayproducesignificantobstructionoftheairwaysandesophagus.This
chapterdiscussesthesevariousanomaliesoftheaorticarchandpulmonary
arteriesthatmaycauseobstructiontothecentralairways.
AnomaliesoftheAorticArch
Theobstructivelesionswithinthearch,suchascoarctationorinterruption,are
notgenerallyincludedinadiscussionofabnormalitiesinpositionand/or
branchingoftheaorticarch.Insightintothemodeofdevelopmentofthearterial
trunksandtheirpatterninthefetalcirculationistremendouslyhelpfulin
understandingtheprenatalandpostnatalfeaturesofthevariousmalformations
thatinvolvetheaorticarch.
HypotheticalModeloftheDoubleAortic
Arch
Thenormalandabnormaldevelopmentofthecomponentsoftheaorticarchcan
bestbeunderstoodbyreferringtothemodelintroducedin1948bythepioneer
pathologist,JesseE.Edwards(Fig.47.1).1,2Themodelillustratesarelatively
latestageofdevelopment,inthatthedistalintrapericardialoutflowtracthas
beendividedintotheascendingaortaandpulmonaryarterialtrunk,andthe
descendingaortaoccupiesaneutralposition.Theearlierstagesofdevelopment
arenotdiscussed,inpartbecausetheprecisemorphogenesisoftheoutflow
tractshasyettobeclarified.Inthehypotheticalmodel,symmetricaorticarches
connecttheascendinganddescendingaortaoneachside,formingacomplete
vascularringaroundthetracheaandesophagus.Eachaorticarchgivesrise
superiorlytoacommoncarotidarteryandasubclavianartery.Oneachside,
right-sidedandleft-sidedarterialductspassbetweenthepulmonaryarteriesand
thedistalpartoftheaorticarches,forminganadditionalvascularringaroundthe
tracheaandesophagus.Thereforethehypotheticalmodelismadeupoftwo
vascularringsjoinedtogetheratthedescendingaorta.
FIG.47.1 Thehypotheticalmodelfortheperfectdoubleaorticarch
proposedbyJesseE.Edwards.Allmalformationsinvolvingthearchcanbe
