Andersons pediatric cardiology 1327
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FIG.50.11 (A)Complexpulmonaryarteriovenousmalformation(PAVM),a
segmentalartery(whitearrow)andseveralsubsegmentalbranchesare
feedingthePAVMs(blackarrows).(B)Transcatheterocclusionof
segmentalandsubsegmentalbranchesusingmultiplecoils.Alarge
segmentalarteryfeedingacomplexPAVM(C)afterocclusionofthe
feedingartery(D)usingmultipleAmplatzervascularplugs(whitearrow).
ManydeviceshavebeensuccessfullyusedtoembolizePAVMs.
Conventionally,coilswereusedforfeedingarteriesmeasuring3to9mm(see
Fig.50.8).However,PAVMsacpersistenceinupto25%,recanalization,and
collateralizationratesof5%to19%canoccur.54,97–99Severalserieshave
indicatedhigherincidenceofrecanalizationwithcoilswhenusedsinglyor
placedgreaterthan1cmfromthePAVMsac.59,95Inrecentyears,theAmplatzer
vascularplughasbecomethepreferreddeviceforembolizationduetoitsability
tooccludelarge-calibervesselswithasingleplug(Fig.50.12),withprecise
occlusionatorproximaltotheneckofthesac,therebyreducingproceduretime
andradiationexposure.94Acombinationofembolizationwithvascularplugs
andcoilshasdemonstratednorecanalization6to40monthsafterTCE.100An
alternatetechniquetooccludePAVMsandreduceriskofreperfusionistoblock
thedrainingvenoussac.Arecentstudyusingthistechniquedemonstratedno
significantdifferencesinPAVMcharacteristics,follow-upduration,and
complicationsbetweenthetwotechniques.However,thereperfusionofthe
PAVMsinthearterialgroupwas50%,andnoreperfusionwasencounteredin
thevenoussacembolizationgroup(P<.1).101ComplicationsofTCEarelowin
experiencedcenters.Postembolizationtransientpleurisyisreportedin10%.
Paradoxicalembolismofdevices,thrombi,orairbubblesisrarewithcurrent
techniques.Ararepostembolizationcomplicationincludesmassivehemoptysis
frombronchialcollateralsrequiringsystemicandpulmonaryangiographic
approachesforembolization.102,103Pulmonaryhypertensionremainsarelative
contraindicationforanelectiveTCEbecauseitcanleadtoacuteincreasein
pulmonaryarterypressure.However,itcanbecarefullyconsideredinselect
patientsbecauseitcanreduceriskofhemoptysisduetoruptureofthePAVM.
Life-threateningcomplications,includingPAVMbleedandstroke,are
experiencedinasmallpercentageofpregnantwomen,and1%ofpregnancies
resultedinmaternalandfetaldeath.90ForsignificantPAVM,third-trimester
TCEisconsideredsafeandfeasible.90SurgicalresectionofthePAVMsis
uncommonnowadaysbecausecatheterembolizationtherapyhasbecomethe
standardpractice.SurgeryisreservedforrarePAVMsdeemednotsuitablefor
embolizationandisalsousedemergentlytocontrolhemorrhage.Thesurgical
techniquesincludelocalexcision,ligation,segmentalresection,lobectomy,and
rarelypneumonectomy.
FIG.50.12 A5-year-oldboywithseverecyanosis(oxygensaturationin
themid-70s)withlargecomplexpulmonaryarteriovenousmalformation(A)
intheleftlowerlungdemonstratingdilatedsegmentalarteryandlarge
pulmonaryvein(whitearrows);therewereadditionalfeedersfromadjacent
subsegmentalarteries(smallblackarrows,BthroughE).Complete
occlusion(F)wasaccomplishedusingmultipleAmplatzervascularplugs
typeIV(notchedblackarrow),AmplatzervascularplugstypeII(notched
whitearrow),microvascularplug(smallwhitearrow),andcoilsofvarying
sizes(curvedblackarrows),withimprovedoxygensaturationintothemid90s.
DespitetreatmentwithembolizationorsurgeryoflargePAVMs,smallPAVMs
persistandnewPAVMsmaybeformedinpatientswithHHT.Thereforetheuse
ofantibioticprophylaxisforproceduralrisksforbacteremia(dentalprocedures)
isrecommended.OtherprecautionsthatarewarrantedforpatientswithPAVMs
includeavoidingairbubblesduringintravenousaccessandavoidingSCUBA
divingduetoriskofparadoxicalembolifromdecompressionsickness.82The
follow-upevaluationofPAVMscouldincludeCTscansat6to12monthsand
every3yearsthereafteraccordingtocertainguidelines;however,incommon
practice,routineCTscansarenotgenerallyadvocatedduetotherisksof
radiationexposure.104Alternativeapproachesincludeamodifiedmanagement
flowchart(Fig.50.13),useofMRI,andlimitinguseofCTscansforpatients
withsymptoms,lowoxygensaturation,orfailuretoobliterateaPAVMsac.47
