Andersons pediatric cardiology 1262
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (194.26 KB, 3 trang )
FIG.47.9 Modeofformationofarightaorticarch(RAA)withmirror-image
branchingandretroesophagealcourseoftheleft-sidedarterialduct
betweentheright-sideddescendingaortaandtheleftpulmonaryartery
(LPA).Inthehypotheticalmodel(left),theredbarsindicatetheregression
oftheleftaorticarch(LAA)betweentheoriginsoftheleftsubclavianartery
(LSA)andtheleftarterialduct,alongwiththerightarterialduct.Inthefetal
circulation(middle),aU-shapedvascularloopisformedaroundthe
posterioraspectofthetracheaandesophagus.Inpostnatalcirculation
(right),theleft-sidedarterialductarisesfromtheright-sideddescending
aortaviaadiverticulumofKommerell,extendingtotheLPAtoproducea
completevascularringinthisrareanomaly.LCCA,Leftcommoncarotid
artery;LIA,leftinnominateartery;MPA,mainpulmonaryartery;RCCA,
rightcommoncarotidartery;RPA,rightpulmonaryartery;RSA,right
subclavianartery.
Circumflexretroesophagealaorticarchisarareformofaorticarchanomaly
inwhichtheaorticarchandtheproximaldescendingaortaareplacedon
oppositesidesofthespine(Fig.47.10AandB).33,34Thiscombinationrequires
theaorticarchtomakeanadditionalarctotheothersidebehindthetracheaand
esophagus,thusreachingthedescendingaortaontheoppositeside.Thepatterns
ofbranchingofthebrachiocephalicarteriesarevariable.Itishardtoexplainthis
raremalformation.Itoccursmuchmorefrequentlywitharight-sidedthanwitha
leftaorticarch.Whenitoccurswitharightaorticarch,thearchgivesrisetothe
leftcommoncarotid,rightcommoncarotid,andrightsubclavianarteryfromits
segmentontherightsideofthetrachea.Thentheaorticarchmakesasharp
obliqueleftwardandusuallydownwardturntoconnecttotheleft-sided
descendingaorta.Theleftsubclavianarteryarisesfromthetransitionalpointof
theretroesophagealpartofthearchtothedescendingaorta.Itcanbenamedas
anaberrantarteryinthesensethatitisthelast,insteadofthefirst,branchofthe
rightaorticarch.Itisnotretroesophagealinlocation,buttheaorticarchitselfis
behindtheesophagus.Inmostcasestheleftsubclavianarteryarisesfromthe
aortathroughadiverticulumofKommerell.Theapexofthediverticulum
connectstotheleftpulmonaryarterythroughaleftarterialligament,thus
formingacompletevascularringaroundthetracheaandesophagus.A
circumflexretroesophagealaorticarchisrarelyseenwithoutaberrantoriginofa
subclavianarterybutdoesexist.29Hypoplasiaoftheretroesophagealsegmentof
theaorticarchiscommon.34
FIG.47.10 (A)Computedtomogramsshowingacircumflexand
retroesophagealright-sidedaorticarch.Theaorticarchislocatedonthe
rightsideofthetracheaandmakesasharpobliqueleftwardanddownward
turntocoursebehindtheesophagustoconnecttotheleft-sided
descendingaorta.Theleftsubclavianartery(LSA)arisesfromthetopof
thedescendingaorta,withthepresenceofadiverticulumsuggestingthata
left-sidedarterialligamentispresentbetweentheapexofthediverticulum
andtheproximalleftpulmonaryartery(LPA).(B)Renderingofthis
arrangement.LCCA,Leftcommoncarotidartery;LVA,leftvertebralartery;
MPA,mainpulmonaryartery;RAA,rightaorticarch;RCCA,rightcommon
carotidartery;RPA,rightpulmonaryartery;RSA,rightsubclavianartery;
RVA,rightvertebralartery.
Theaorticarchisdescribedasbeingcervicalwhenitsapexreachestheupper
mediastinumabovetheleveloftheclavicles(Fig.47.11).35–37Itmaybe
recognizedasapulsatilemassinthesupraclavicularfossaorlowerneck.A
cervicalarchisslightlymorecommonontheright,oftentakingacircumflex
retroesophagealcoursetoformavascularring.Adoubleaorticarchcanalso
adoptacervicalposition.Thebranchingofthebrachiocephalicarteriesis
abnormalinthemajorityofcases.Inaddition,itiscommontofindunusual
tortuosity,obstructionandaneurysmoftheaorticarch,andobstructionofa
brachiocephalicbranchorbranches(Fig.47.12).Acervicalaorticarchisoften
associatedwithtrachealobstructionbecauseofcrowdingofvascularstructures
andairwayinaconfinedsmallspaceoftheuppermediastinum,especiallywhen
theaorticarchisrightsidedandtakesahairpinturn.38
FIG.47.11 Magneticresonanceangiogramshowingaso-calledcervical
rightaorticarch(RAA),whichreachestotheapexoftherightlung,whereit
makesahairpinturn.Itshowsmirror-imagebranching,butthebranches
aretortuous,andtheoriginoftherightsubclavianarteryisaneurysmally
dilated.LCCA,Leftcommoncarotidartery;LIA,leftinnominateartery;LSA,
leftsubclavianartery;RCCA,rightcommoncarotidartery;RSA,right
subclavianartery.
