Andersons pediatric cardiology 1322
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thisprecursorisactuallythedilatedchannel.TheveinofGalenisthedilated
channelwhenthearteriovenousconnectionsdraindirectlyintotheveinof
Galen,whichisconsideredaseparateentity.Anumberofdifferentclassification
schemeshavebeenusedtodescribetheselesions.32,33VGAMsmayconsistofa
networkofvesselsordirectarterialfeedersintothemedianprosencephalicvein
ofMarkowski.AssociationsofVGAMswithRASA1andACVRL1gene
mutationshavebeenreported.34,35Inaddition,afamilialassociationofVGAMs
hasbeendescribed.36
Theclinicalmanifestationsarevariableanddependontheageatpresentation,
whetherintheneonatalperiod,infancy,childhood,oradulthood(lesscommon).
Duetoincreasingsophisticationofprenatalimaging,fetalpresentationisbeing
reportedmorecommonly.Itisnotuncommonforneonatesandinfantswith
VGAMstobemisdiagnosedordiagnosedlateduetotherarityofthislesion.
Neonatesgenerallypresentwiththeseverestformofthedisease,with
tachypnea,fatigue,poorfeeding,andpoorgrowth.Systemicorgan
hypoperfusioncanmanifestifthereissignificantrunoffintheaortaandcanlead
tosignsofintestinal,renal,orhepaticischemia.Inseverecases,
cardiorespiratorycompromisemayensueifleftuntreated.Neurologic
compromisecanmanifestasseizures,developmentaldelay,andheadachesin
patientswhopresentlate.37,38Physicalexaminationrevealsadynamiccardiac
precordiumandboundingpulsesfromrunoffintheaortaduetothe
arteriovenousshunting.Signsofpulmonaryhypertensionwithaloudpulmonary
componentofthesecondheartsoundmaybepresent.Macrocephalyfrom
hydrocephaluscanbepresent.37,38Acharacteristiccranialbruitmaybeheardon
auscultation.
Chestradiographsrevealcardiomegaly(Fig.50.1)insymptomaticpatients,
particularlyneonates.Cardiacchamberenlargementorhypertrophycanbeseen
onelectrocardiograms.Transthoracicechocardiographyconfirmscardiac
chamberenlargement,whichisusuallyoftherightsideoftheheart(Fig.50.2)
butmayprogresstoenlargementofallchambersand,ifleftuntreated,
eventuallyimpactsventricularfunction.Signsofpulmonaryhypertensionmay
beapparentbytransthoracicechocardiography.Dopplerultrasoundisauseful
screeningtoolinneonatesandcandetectthedilatedvenoussac(Fig.50.3)and
hydrocephalus.However,CTandMRwithangiography(Fig.50.4)areneeded
toevaluateforcerebralatrophy,abnormalitiesinvenousdrainagepathways
(e.g.,thromboses),intracranialhemorrhage,andthedetailsofthearteriovenous
connections.39,40Conventionalangiographyviathecarotidarteriesisgenerally
reservedforinterventionalpurposes.Fetalcardiacdiagnosticfeaturesof
VGAMsbyultrasoundconsistofanenlargedcardiothoracicratio,reversalof
diastolicflowacrosstheaorticisthmus,andsignificanttricuspidregurgitation
velocityandseverity;significanttricuspidregurgitationinthefetuswithVGAM
isconsideredapoorprognosticindicator.41
FIG.50.1 Chestradiograph(posterior-anteriorprojection)ofaneonate
withaveinofGalenaneurysmalmalformation.Massivecardiomegalyis
noted.
FIG.50.2 InthesameneonateshowninFig.50.1,thistwo-dimensional
transthoracicechocardiograminthefour-chamberviewdemonstratesa
severelydilatedrightatriumandrightventricle.
FIG.50.3 NeonatalheadultrasoundoraneonatewithaveinofGalen
aneurysmalmalformationshowingthedilatedvenouschannel(themedian
prosencephalicveinofMarkowski)bytwo-dimensionalimaging(A,arrow)
andwithDopplercolorflowmapping(B).
