Andersons pediatric cardiology 1354
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ClinicalFeatures
AOPAoccursmostcommonlyasanisolatedcardiacanomaly,withtherightPA
arisingfromtheascendingaorta(andtheleftPAarisingnormallyfromthemain
PA)beingeighttimesmorecommonthantheleftPAarisingfromtheaorta.38
However,associatedheartdefectscanexistandmayincludesimpledefectssuch
aspatentarterialductandatrialorVSD,ormorecomplexones,including
variantsoftetralogyofFallot.39,40Thereisa2:1preponderanceofmalesto
femaleswithAOPA.38Thephysiologyofthiscondition,intheabsenceofother
defects,involvestheentiretyofthesystemicvenousreturnflowingtothe
normallyconnectedPAviatherightventricleandmainPA,representingthe
effectivepulmonarybloodflow.Theaffected(i.e.,typicallyright)PAreceives
bloodviatheascendingaortawithoutanyproximalstenosisandishenceat
systemicpressure.FlowtotheaffectedPArepresentsaleft-to-rightshuntand
leadstoexcesspulmonaryvenousreturntotheleftatriumandleftventricle,
leadingtotheexpectedleftheartdilation.Indeed,congestiveheartfailureisthe
presentingsymptomin95%ofcasesandisusuallypresentinthefirstyearof
life.38
Management
Interestingly,thePAthatisnormallyconnectedtothemainPA(i.e.,typicallythe
leftPA)isfrequentlyfoundtohaveelevated(near-systemic)pressures,a
puzzlingandpoorlyunderstoodphenomenon,albeitwelldescribed.37,41
Mortalityamongunoperatedpatientsisveryhigh,estimatedat30%inthefirst
monthoflifeand70%at1year.38MedicalmanagementofAOPA,suchasuse
ofdiuretics,servesonlytotemporizeuntildefinitivesurgicalrepaircanbe
accomplished.SurgicalmanagementofAOPAconsistsoftransectionofthePA
thatarisesfromtheaortawithreimplantationintothemainPA.Whenever
possible,reimplantationshouldbeperformeddirectly(withoutagraft),a
techniqueinitiallydescribedbyKirkpatrickandcolleagues.42Avoidanceofa
graft(particularlysyntheticgrafts)isdesirablebecausethesegraftshaveno
growthpotentialandneedtobereplacedtoaccompanyachild'sgrowth.
LargeseriesdescribingthemanagementandoutcomesofpatientswithAOPA
arelackingbecauseoftherarityofthiscondition.Aseriesof16patientsovera
periodof36yearspublishedfromtheHospitalforSickChildren,Toronto,
revealedthat12of16casesinvolvedanomalousoriginoftherightPAand4
involvedtheleft;noneoftheanomalousPAshadpreexistingstenosisatthesite
ofaorticorigin.Theirseriesreporteda25%mortalityrate(2of16werenot
offeredsurgery,whereas3sufferedintraoperativedeaths).43Ofthe11operative
survivors,8developedstenosisatthePAreimplantationsite.Anotherseriesby
Pengdescribed9patientsovera29-yearperiod,40withallcaseshaving
anomalousoriginoftherightPAabovetheaorticsinus,andallbeingfreeof
preexistingstenosisattheaorticorigin.Two-thirdsofpatientshadnomajor
associateddefects,andone-thirdhadrightventricularoutflowtractobstruction
intheformoftetralogyofFallotoravariantthereof.Anastomosisoftheright
PAwasperformedinall,withoutoperativemortality.However,theincidenceof
anastomoticstenosiswasnotprovided.Thelargestseriestodate,from
Children'sHospitalBoston,described29patients,ofwhich27hadaorticorigin
oftherightPAandonly2withaorticoriginoftheleft.44Stenosisatthe
anastomoticsitedevelopedin79%ofpatients,mostofwhomunderwent
successfulcatheter-basedinterventionstorelievestenosis.
AortoventricularTunnels
Inmostinstances,theselesionsproducecommunicationsfromtheaorticsinuses
tothecavityoftheleftventricle(Fig.51.13).Thetunnelscanalsoextend
betweentheaorticrootandthecavityoftherightventricle(Fig.51.14).45On
rareoccasions,theycanopentothecavityoftherightatrium.However,the
morphologyofthetunnelsterminatingintherightatriumisquitedifferentfrom
thoseextendingtoopentotheventricles.Itisarguablethattherightatrial
tunnelswouldbetterbedescribedasfistulouscommunications.Withregardto
thetunnelsproducinganomalousconnectionswiththeventricles,themajorityof
thosereportedthusfarhaveproducedconnectionswiththeleftventricle,with
onlyapproximatelyone-eighthofreportedcasesinvolvingtherightventricle.It
iswellestablishedthatthehistologicappearanceoftheaorticendofthetunnel
differsmarkedlyfromtheventricularcomponent.Thisishardlysurprising
becausetheessenceofthetunnelsisthat,whencommunicatingwiththeleft
ventricleandtakingtheiroriginfromanaorticvalvarsinus,theybypassthe
hingeoftheaorticvalve(Fig.51.15).
FIG.51.13 Aortoventriculartunnelterminatingintheleftventricle.(A)
Enlargedwalloftherightcoronarysinusasseenfromthefront.(B)Probe
passedthroughthetunnel,whichbypassesthehingeoftherightcoronary
aorticleaflet,openingintotherightventriclethroughtheunguarded
interleaflettrianglebetweenthetwocoronaryaorticvalvarsinuses.
