Andersons pediatric cardiology 1270
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sling.Highleftparasternalshort-axisviewsofthepulmonaryarteriesreveal
thatthepulmonarytrunk(PT)continuesastherightpulmonaryartery
(RPA),withoutgivingrisetoanormalleftpulmonaryartery.Theleft
pulmonaryartery(LPA)arisesfromtheRPAbehindtheascendingaorta.
TheLPAthenmakesahairpinturntocoursetotheleftside,encirclingthe
tracheafromtherightside.ThisanatomycanbeappreciatedwhenthePT
isfollowedasitmovestotheright.NotethattheproximalpartoftheLPAis
notclearlyshowninthecross-sectionalimagesbecauseofsonic
shadowingfromtheair-filledtrachea.MPA,Mainpulmonaryartery;SCV,
superiorcavalvein.
Bothcomputedtomographyandmagneticresonanceimagingare
diagnostic.79,87,88Contrast-enhancedcomputedtomographyispreferred,not
onlybecauseofitsabilitytovisualizethepulmonaryvesselsandairwaywith
greatprecisionbutalsobecausetheshorttimerequiredforscanningobviatesthe
needforgeneralanesthesiaordeepsedationincriticallyillpatients.Threedimensionalreconstructionoftheairwaysandthecontrast-enhancedvascular
structuresprovidescompleteinformationforthesubsequentsurgicalprocedure.
Whenthenarrowingoftheairwaysisconsidereddynamic,afewselectedslices
canbescannedrepeatedlyforcine-displayduringrespiration.68,69Complications
suchashyperinflation,collapse,orconsolidationofthepulmonaryparenchyma
duetopneumoniashouldalsobeevaluated.Althoughmagneticresonance
imagingcanprovidecomparableinformation,thetimerequiredforscanningis
longandtheanatomicdetail,especiallyoftheairwaysandlungs,isnotasgood
asthatofcomputedtomography.Bronchoscopyisrecommendedwhendynamic
narrowingduetotracheomalaciaorbronchomalaciaissuspected.Routine
intraoperativebronchoscopycanbeusefulbecausetherightandleftbronchi
distaltothecompletecartilaginousringsmayalsoshowmalacicchanges.10
ManagementofAnomaliesCausing
TrachealandEsophagealCompression
IndicationsforSurgicalIntervention
Thefirstsurgicalrepairofavascularringanomaly,adoubleaorticarch,wasby
Dr.RobertGrossatBostonChildren'sHospitalin1945.89Thelong-standing
historywithsurgicalinterventionfortheselesionshastaughtusthat
symptomaticpatientsshouldundergorepairwithoutdelay.90Airwaysymptoms
includestridor,wheezing,cough,andrecurrentrespiratoryinfections.Itisnot
uncommonforanolderchildtopresentforrepairafterchronictreatmentfor
reactiveairwaydiseaseorasthma.Esophagealcompressioncanpresentwith
dysphagiaandchokinginanolderchildtakingsolidfoods.Untiltheextrinsic
airwaycompressionisrelieved,thetracheomalaciainsymptomaticpatientswill
notimprove,makingdelayinsurgicalcorrectionunwise.Delayedsurgical
interventionmayalsoleadtopersistentdysphagia,91thepotentialforaortic
dissection,92andthepossibilityoflife-threateninggastrointestinalbleeding.93–95
Oncethedecisionismadetoproceedwithrepair,echocardiography,magnetic
resonanceimaging,orcomputedtomographyareusedtoplantheprocedure.
Thesemodalitiesprovidethedetailnecessaryforsuccessfulreliefoftracheal
andesophagealcompressionandforrepairofassociateddefects.Fiberoptic
bronchoscopyisausefulintraoperativeadjuncttoassessthesuccessofthe
vascularringrepairsimilartotheuseofintraoperativetransesophageal
echocardiographytoassessintracardiacrepair.
SurgicalApproaches
Vascularringscanberepairedusingbothopenandclosedsurgicalapproaches,
butmostvascularringanomaliesarerepairedbyaleftposterolateral,musclesparingthoracotomy.Thelatissimusdorsimuscleisdivided,andtheserratus
anteriorissparedandcanberetractedanteriorlywithasmallvesselloop.The
aortaisexposedthroughthethirdorfourthintercostalspace.Aright
thoracotomyischoseninpatientswherethedescendingaortaistotherightof
thespine.Amediansternotomyisusedinpatientswhorequireconcomitant
intracardiacrepair,96repairofpulmonaryarterysling,ortheaorticuncrossing
procedureforcircumflexaorta.97Theclosedtechniqueofvideo-assisted
thoracoscopyfordivisionofvascularringanomalieswasinitiallydescribedin
1993.98Itusesfourportaccessincisionstoperformtheprocedure,whichdoes
notdivideanyofthechestwallmusclesorspreadtheribsforexposureofthe
aorta.99Thisleadstolesspostoperativepainandanicecosmeticresult.Oneof
thelargestsingleinstitutionexperienceswiththisapproachwasreportedfrom
BostonChildren'sHospital,wheretheprocedurewasinitiallydescribed.Over
thecourseof25years,theyhaveperformedthoracoscopic(video-assisted
thoracicsurgery)vascularringdivisionin115patients,butonlyfourofthose
patientshadpatentarches.100Thelackofenthusiasmforthisapproachin
patientswithapatentarchmayberelatedtothepotentialdifficultyincontrolling
catastrophichemorrhagewhendividingapatentdoubleaorticarch.101Also
notablefromtheBostonexperiencewasadecreasingpercentageofpatients
undergoingtheVATSprocedureinthecurrentsurgicalera(55%in1991to
2005,45%in2006to2015).101
SurgicalTechnique
DoubleAorticArch
Centraltotherepairofadoubleaorticarchisdivisionofthesmallerofthetwo
archesanddivisionoftheligamentumarteriosum.Mostcommonlytheanterior
orleftarchissmaller.Thesegmentoftheleftarchbetweentheleftsubclavian
arteryandthedescendingthoracicaortaisdivided.Thesizeofthissegmentis
variable.Itcanbeatretic,inwhichcasesimpleligationanddivisionis
performed(Video47.1).However,thissegmentcanalsobewidelypatentand
requiredivisionbetweenvascularclamps.Afterdivision,eachendisoversewn
withacontinuousProlenesuture.Failuretodividetheligamentumarteriosum
maybeacauseforpersistenceofsymptomsaftertherepair.Theesophagusand
descendingaortashouldalsobefreedofanyadhesivebands.6Theadditionofan
aortopexyinapatientwithadoubleaorticarchhasbeensuggested.Whenthe
smallerarchandligamentumarteriosumaredivided,thisallowstheposterioror
rightarchtoretractawayfromthetracheaandesophagus,whereitcourses
behindthesestructures.6Thisisalsothepointatwhichlife-threatening
hemorrhagecanoccurandbeverydifficulttocontrol.Inpatientswitha
dominantposteriorarch,thisadvantageoftherepairislostwhenaposterior
aortopexyofthedescendingaortaisperformed.Forthisreason,itisnot
