Andersons pediatric cardiology 1264
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Incidence,Genetics,andAssociation
WithAnomalies
Theoverallincidenceofanomaliesinvolvingtheaorticarchisdifficultto
estimatebecauseanunknownbutsignificantnumberofindividualshavingsuch
anomaliesdonotpresentwithsymptomsandthusremainundiagnosed.
Thereforethereportedincidencesofindividualanomaliesvarysignificantly
accordingtothepopulationstudied.Aleftaorticarchwithaberrantoriginofthe
rightsubclavianartery,whichisusuallyfoundincidentallyandasanisolated
defect,hasbeenreportedasthemostcommonaorticarchanomaly.Ithasbeen
foundin0.5%ofalargeautopsyseries.2Inpatientswithothercardiacdefects,a
rightaorticarchwithmirror-imagebranchingisthemostcommon
malformation.29Associationwithcongenitallymalformedheartsvaries
accordingtotheindividuallesions.Arightaorticarchwithmirror-image
branchingisalmostalwaysassociatedwithcongenitalcardiacdisease.29Aright
aorticarchiscommonintetralogyofFallotandcommonarterialtrunk,withthe
incidencerangingfrom20%tomorethan30%forbothlesions.Whentetralogy
isassociatedwithpulmonaryatresia,theincidenceishighat30%.Amirrorimagerightaorticarchislessfrequentlyseenintransposition,tricuspidatresia,
andisolatedventricularseptaldefect.Whennotassociatedwithintracardiac
anomalies,themirror-imagedrightaorticarchiscommonlyassociatedwith
absenceorstenosisoftheproximalleftpulmonaryartery.29Theraremirrorimagedrightaorticarchwithretroesophagealleft-sidedarterialductis
uncommonlyassociatedwithothercardiovascularanomalies.Rightaorticarch
withaberrantleftsubclavianarteryisalsolesscommonlyassociatedwith
congenitalcardiacdisease,withthereportedincidencerangingfromlessthan
20%tomorethan60%.4,6Themostcommonlyassociatedmalformationsare
ventricularandatrialseptaldefects,tetralogyofFallot,andtransposition.Left
aorticarchwithaberrantrightsubclavianarteryismuchlesscommonly
associatedwithothermalformationsandthereforeisusuallyfoundasan
incidentalfinding.Doubleaorticarchisassociatedwithothercardiovascular
anomaliesinupto20%ofcases,themostcommonbeingatrialandventricular
septaldefects,tetralogyofFallot,andpatencyofthearterialduct.4–9Circumflex
retroesophagealaorticarchisassociatedwithcongenitallymalformedheartsin
uptohalfofcases.33Althoughuncommon,arightaorticarchwithorwithoutan
aberrantleftsubclavianorbrachiocephalicarterymaybeassociatedwithan
obstructivelesionoftheaorticarch,especiallywhenthearchformsacircumflex
retroesophagealorhighcervicalcourseorboth.46–48Rarely,interruptioncanbe
foundinarightaorticarch.47,49
Noncardiacanomaliesareinfrequentlyassociatedwithanomaliesoftheaortic
arch.Themostimportantnoncardiacanomalyistheesophagealatresiawithor
withoutthevertebral,anal,cardiac,tracheal,esophageal,renal,andlimb
anomaliesassociation.8,50,51Ithasbeenreportedthatesophagealatresiaseenin
associationwithsuchanomaliesoftheaorticarchtendstohavealonggap.50
Chromosome22q11deletionsyndromeiscommon.52–54Thisdeletionis
consideredtoaffectmigrationofcellsfromtheneuralcrestthatcontributeto
developmentoftheventricularoutflowtractsandpharyngealarchesinthe
embryo.However,theprecisemechanismsofabnormaldevelopmentofthe
aorticarchesremainspeculative.Afetalseriesshowedan8%incidenceof
22q11deletioninfetuseswitharightaorticarchasanisolatedabnormality,and
46%inthosewithrightaorticarchandintracardiacabnormality.19Postnatal
seriesshowedhigherincidencesof22q11deletion,thisbeingfoundinuptoonequarterofcaseswithanisolatedanomalyoftheaorticarch.52,53Thehigher
incidenceof22q11deletioninpostnatalseriesisexplainedbyselectionbias
becausethesepatientsaremorelikelytobereferredtoacardiologist.19More
thanhalfofthepatientswithanintracardiacanomalyand22q11deletionhave
ananomalyoftheaorticarch.54Inpatientswithanomaliesoftheventricular
outflowtracts,anomaliesofthesubclavianarteriesfunctionasanimportant
anatomicmarkerforchromosome22q11deletion,independentofthelaterality
oftheaorticarch.55Thesubclavianarterialanomaliesencompassaberrantorigin
fromthedescendingaorta,isolatedorigin,distalductaloriginfromthe
pulmonaryartery,andcervicalorigin.Chromosome22q11deletionwaspresent
ingreaterthan75%ofsuchpatientswithabnormalitiesoftheventricular
outflowtractsandabnormalsubclavianarteries,whereasitwaspresentinless
than30%whentherewasnosubclavianarterialanomaly.Thepatientswith
tetralogyofFallotwithchromosome22q11deletionshowhigherincidenceof
cervicalaorticarch.56Downsyndromehasalsobeenshowntobeassociated
withanincreasedriskforaberrantrightsubclavianartery.5,57,58Therefore,inthe
presenceofananomalyoftheaorticarch,fetalkaryotypingisrecommended,
especiallywhenitisassociatedwithintracardiacanomalies,extracardiac
malformations,oranincreasednuchaltranslucency.19
