Andersons pediatric cardiology 1329
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FIG.50.16 Originanddrainagesitesofcoronaryarteryfistulas(CAFs).
Smallcoronaryarteryfistulafromtheleftcoronarysystemtothepulmonary
artery(A,smallwhitearrows).ModeratetolargeCAFsarisingfromtheleft
maincoronaryarterydraining(whitearrows)intotherightatrium(B),
coronarysinus(C),rightventricle(D),andleftatrium(E).LargeCAF
arisingfromtherightcoronaryarterydrainingintotheleftventricle(F,white
arrow).
ClinicalFeatures
Theclinicalfindingstypicallyincludeacontinuousmurmurwithdiastolic
accentuationinthosewithamoderateorlargeCAF,oranearlydiastolicmurmur
canbeheardwhenitdrainstotheleftventricle.Thehemodynamicburden,
clinicalfeatures,symptoms,andsiteanddegreeofchamberdilationarerelated
tothesizeofthefistulaandthesitesoforiginanddrainage.CAFsdrainingto
therightheartrepresentleft-to-rightshuntscreatingvolumeloadtothereceiving
chamberandeachchamberandvesselinsuccessionuptotheleftventricle.
CAFsdrainingtothepulmonaryarteriesmimicpatentarterialduct
hemodynamically.CAFsdrainingtotheleftheartdonotrepresentaleft-to-right
shuntbutdoresultinvolumeloadtotheleftheart;inthisregard,CAFsarein
somewayssimilartomitralregurgitationwhentheydraintotheleftatriumand
causehemodynamicchangessimilartoaorticinsufficiencywhentheydrainto
theleftventricle.111,114Thedegreeofshuntisdirectlyproportionaltothesizeof
thefistulaandthepressuregradientbetweenthecoronaryarteryandthedraining
chamberorvessel.ThereforepatientswithsmallCAFsandsmallshuntsare
generallyasymptomatic,andthosewithsignificantshuntscanoccasionally
presentwithCHF.Inadults,inadditiontodegreeofshuntandvolumeload,
CAFscancausecoronary“steal”phenomenonduetopreferentialrunoffof
bloodthroughthefistulabypassingdistalcoronarybranchesandmyocardium.It
isthereforenotuncommonforadultstopresentwithanginawhenCAFsinthe
presenceofcoronaryarterydisease.108
MostchildrenwithCAFsareasymptomaticandareusuallydetectedduring
evaluationofamurmur.SmallCAFsarehemodynamicallyinsignificantand
remainasymptomaticwithpropensityforspontaneousclosure,asnotedoverthe
meanfollow-upof9.3yearsinthelargeststudyofthispatientsubgroup.115–119
MostchildrenwithmediumandlargeCAFsareasymptomatic;inonestudy,
only19%presentedwithsymptomsorcomplicationsrelatedtoaCAF.108
However,CAFsymptomsandcomplicationsweremoreapparentinpatients
diagnosedafter20yearsofage.108PotentialconsequencesofCAFinclude
anginaduetocoronarystealcausingmyocardialischemia,thrombosisand
embolism,arrhythmias(e.g.,atrialfibrillation),endocarditis,andrarelycoronary
aneurysmrupturecausinghemopericardium.108,111,114,120–122LargeCAFsmay
presentwithsignsofCHF,especiallyinneonatesandinfants.108,123–125Large
CAFsthatareasymptomaticareduetosmallershuntssecondarytonaturalnear
completerestrictionatthedrainagepoint.CAFscanprogressivelyincreasein
size,causinglongtortuousfistulasegments.Theaneurysmalsectionofthe
fistula,especiallyatthedrainagepoint,canprogressivelydilateorrupture
causinghemopericardium108,114,121,122orbethefocusforthrombosiscausing
myocardialinfarctionorinduceatrialandventricular
arrhythmias.108,112,113,126–128
Investigations
Anelectrocardiogram(ECG)andchestx-rayaregenerallyunhelpfulforthe
diagnosisofCAF.ECGchangesareusuallynonspecific,andseverallargeseries
demonstratedventricularhypertrophytobepresentin16%to66%.111,129
Ischemicchangesareuncommonbutcanbemorefrequentwithincreasingage
andcanbeinducedwithexercisestresstest.130Chestx-raysareusuallynormal,
buttheycanoccasionallydemonstratecardiomegalyorpulmonarycongestionin
largefistulaswithCHF.Anabnormalchestx-raywasnotedin75%ofpatients
whorequiredsurgicalinterventioninalargeseries.129,131
Echocardiographyistheprimarytoolfordetectionanddiagnosisofthese
anomalies.ColorDopplerechocardiographycanbetheinitialtoolindiagnosing
moderatetolargefistulas(andoccasionallysmallfistulas)andcanrevealthe
chamberorvesselintowhichthefistuladrains(Fig.50.17).Demonstrationof
coronaryarterydilation,vesseltortuosity,presenceofananeurysm,andchamber
dilationbytwo-dimensionalechocardiogramcanindicateasignificantshuntin
moderatetolargeCAFs.129,132,133However,thedetailedCAFanatomy
throughoutitscourseanditsrelationshiptodistalcoronarybranchescannotbe
adequatelydefinedwithechocardiography.Coronaryangiographycontinuesto
bethegoldstandardforconfirmingthediagnosisanddelineatingtheimportant
anatomicfeatures,includingthesize,siteoforiginanddrainage,areasof
stenosis,aneurysmaldilation.Furthermore,angiographycanleadtofurther
therapeuticoptions,includingtranscatheterclosure(TCC)ofthefistulaif
feasibleandindicated(seeFigs.50.16and50.18).Initialhemodynamic
assessmentwillprovideinsighttothedegreeofshuntbasedonthepulmonaryto
systemicflowratio,andtheatrialpressuresandventricularend-diastolic
pressurescanindicatelevelofpreloadoncardiacchambers.Aorticroot
angiographywillidentifythecoronaryarteryinvolved,itsproximalrelationship
tothemaincoronaryarterybranches,andthedegreeofdilationofthe
correspondingaorticsinus.Selectivecoronaryarteryangiographyshouldbe
performedforplanningthedefinitivetreatmentespeciallyinsymptomaticor
asymptomaticmediumtolargeCAFrequiringtranscatheterorsurgicalclosure
(SC)(seeFig.50.18).Inolderchildrenandinadultswithlargetortuousfistula
segment,selectiveballoonocclusionwedgeangiogramcanbehelpfulinlocating
thedrainagepointandhighlightthedistributionofnormalcoronarybranches
(seeFig.50.18).Coronaryangiographyinvariousplanesshouldbeperformed,
dependingontheanatomy,andcanincluderightanterioroblique,leftanterior
obliqueandcranialcaudalangulation,straightanteroposterior,andlateral
projections.VisualizationoftheCAFmaybeimprovedusingthelaidback
aortogram(byusingcaudalangulationatupto45degreestothefrontalview
withapproximately5degreesleftanteriorobliqueorientation).134Inolder
childrenandadultswhoareabletoexercise,evaluationwithmyocardial
perfusionorstressthalliumscanningmaydemonstratereversibleischemia.111,135
