Andersons pediatric cardiology 958

FIG.36.14 Seriesofangiogramsdepictingfourlargemajor
aortopulmonarycollateralarteries,oneofwhichconnectstothecentral
pulmonaryartery(arrow)throughaconnectionintherightupperlobe
territory(A).Theotherthree(B–D)provideisolatedsupplytosegmentsin
theright(B)andleft(C–D)lungs.


FIG.36.15 (A–B)Angiogramsfromapatientwithmajoraortopulmonary
collateralarteries(MAPCAs)totherightlung(B)andaductusarteriosusto
theleftlung(A).AsistypicalforpatientswithtetralogyofFallot/pulmonary
atresia/MAPCAsandductus,theleftpulmonaryarteryarborizesnormally
andcompletelyandissuppliedonlybytheductus.Boththeductusandthe
MAPCAshownattherightwerepreviouslystentedbeforereferraltoour
center.Notethatthedescendingaortaisipsilateraltothelungsuppliedby
theductus,andthearborizationoftheleftlung'spulmonaryarterysystem
isnormal,incontrasttotheMAPCA-suppliedrightlung.(C–D)Schematic
ofsingle-stagerepairinthesettingofapatentductustotheleftlungand
twogood-sizedMAPCAstotherightlung.(C–D,FromWatanabeN,
MainwaringRD,ReddyVM,etal.Earlycompleterepairofpulmonary
atresiawithventricularseptaldefectandmajoraortopulmonarycollaterals.
AnnThoracSurg.2014;97:909–915.)


Thereareseveralpointsofnomenclaturethatweuseclinicallythatshouldbe
clarified.ThenumberofMAPCAsisfrequentlyreportedasthenumberof
vesselsarisingfromtheaorta,subclavianarteries,coronaryarteries,orother
systemicarteries.Fromasurgicalpointofview,however,thenumberof
MAPCAsshouldbethoughtofasthenumberofdiscretevesselsthatmustbe
managed(unifocalizedorligated).BecauseMAPCAsthatoriginatefroma
majorsystemicarteryoftendividebeforetheyenterthelungorthepulmonary
arteries,thenumberofvesselsthatmustbemanagedisnotalwaysthesameas

thenumberofdiscreteoriginsfromthesystemiccirculation.Thereforeour
conventionistocounteachMAPCAorbranchthatmustbemanagedseparately,
priortoenteringthelungparenchymaorconnectingwiththepulmonaryarteries,
asauniqueMAPCA.ThedefiningcharacteristicofaMAPCAthatmustbe
managedseparatelyisthatitisorwillbeobstructed(orotherwisehaveafixed
limitationinflow)initsnativestateifitisnotunifocalizedseparately,asismost
oftenthecase,oraugmentedinitsnativeconfiguration(seeFig.36.13).
Anotherimportanttermthatmaynotbeuniversallyagreeduponis“dual
supply,”whichweusetoconnotearobustfunctionalconnectionbetweena
MAPCAorlungterritorysuppliedbyaMAPCAandlungterritorythatisin
continuitywiththecentralpulmonaryarterysystem.AMAPCAthatconnects
robustlytothecentralpulmonaryarterysystemortoanotherMAPCA,either
withinthelungparenchymaorpriortoenteringtheparenchyma,isconsideredto
provideadualsupply.Inthisrespect,“dualsupply”indicatesthattheconduit
portionofthecollateralwillberedundantoncethecentralpulmonaryarteriesare
fedbyarightventricle-to-pulmonaryarteryconnectionorasystemic-topulmonaryarteryshunt.IflungterritorysuppliedbyaMAPCAcommunicates
withanothersegmentorlobethroughacquiredintersegmentalconnectionsor
throughasmallconnectionthatisinadequatetoprovidesufficientflowtothe
lungterritoryinquestion,thatcollateralshouldnotbeconsideredadualsupply
MAPCA.IfaMAPCAdoesnotprovidedualsupply,bydefinitionitisthesole
(orisolated)supplyofbloodtoaparticularregionoflung.Bydefinition,adual
supplycollateraldoesnotneedtobeunifocalizedoraugmentedinorderforthe
lungterritoryitsuppliestoreceiveadequateflowonceacentralsourceof
pulmonarybloodflowisprovided.BoththenumberofMAPCAsand
dual/isolatedsupplystatuscanbedelineatedbyangiographyand/orcomputed
tomography,althoughonlytheformercanprovidedirectdataonpressuresand
gradients.