Andersons pediatric cardiology 1188
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jetofthestenosisadheringtotherightaorticwallpreferentiallydirectedtowards
theinnominateartery,fromwhichtherightsubclavianarteryarises.164
Investigations
Electrocardiogram
Electrocardiogramwilltypicallybenormalorshowleftventricularhypertrophy
withorwithoutstrainrepolarizationchanges.IschemicSTorTwavechangesat
restorduringexercisetestingshouldraisethesuspicionofimpairedcoronary
arterialperfusion.
ChestRadiograph
Chestradiographistypicallynormalinpatientswithsupravalvaraorticstenosis
andisnotusedroutinelyaspartofdiagnosticwork-up.
Echocardiogram
TransthoracicechocardiogramwithDoppleristheinitialimagingmodalityfor
diagnosisofsupravalvaraorticstenosis.Boththestandardandhigh-right
parasternallong-axisimagingplaneswilldisplaythediscreteorhourglass
narrowingoftheascendingaorta,typicallyatornearthesinotubularjunction
(Videos44.12and44.13).TurbulenceisidentifiedbycolorDoppler,andthe
velocityofflowcanbequantifiedbyspectralDoppler.Similartovalvaraortic
stenosis,theestimatedpressuregradientacrossthestenosisbyechocardiogram
isusedtogradetheseverityofobstructionandguidedecisionsregardingtiming
ofintervention.
Echocardiogrammayalsodemonstrateabnormalitiesoftheaorticvalve
leaflets,includingtetheringoftheleafletsatthesinotubularjunction.The
ascendingaorta,aorticarch,andproximaldescendingaortamayalsobe
diffuselyhypoplastic(Fig.44.23).Carefulinterrogationofthecoronaryarteries
withtwo-dimensionalimagingandcolorDopplercanassessforostialstenosis.
Stenosismayalsobeevidentwhenimagingtheproximalbranchpulmonary
arteries.Systolicfunctionandpresenceofhypertrophyoftheleftandright
ventriclesalsoinfluencedecisionabouttimingofintervention.
FIG.44.23 Paneldemonstratingsupravalvaraorticstenosis,in
associationwithhypoplasiaortheascendingaorta.NotethecolorDoppler
turbulencestartsinthesupravalvarregion.AO,Aorta;LA,leftatrium;LV,
leftventricle.
MagneticResonanceImagingandComputed
Tomography
Despitethediagnosticaccuracyofechocardiogram,additionalnoninvasive
imagingisoftenrequiredtoassessthedegreeofanatomicnarrowinginthe
ascendingaorta,aswellasevaluateforstenosisisotherpartsofthearterialtree
includingthebranchpulmonaryarteries.Bothmagneticresonanceimagingand
computedtomographycanprovideexcellentanatomicdetail(Fig.44.24).When
coronarystenosisorinsufficiencyissuspected,magneticresonanceimagingmay
identifymyocardialperfusionabnormalitiesorabnormaltissuecharacteristicsto
suggestpreviousinjury.
FIG.44.24 Computedtomographicangiogramofapatientwith
supravalvaraorticstenosis.Thereisseverenarrowingatthesinotubular
junctionabovethelevelofthecoronaryarteries.Notethenormalsized
aorticroot.
CardiacCatheterization
Cardiaccatheterizationistypicallynotrequiredfordiagnosisofsupravalvar
aorticstenosisgiventheaccuracyandresolutionofnoninvasiveimaging
modalities.However,directpressuremeasurementsmaybeusefulwhenthere
aremultiplelevelsofobstruction,tohelpinformdecisionsabouttimingof
interventionincertaincases.
Management
Interventionisindicatedinthesettingofmoderateorseveresupravalvaraortic
stenosisassociatedwithsymptomsofexerciseintolerance,progressiveaortic
valveinsufficiency,induciblemyocardialischemia,and/orleftventricular
dysfunction.Inasymptomaticpatientswithnormalcardiacfunction,elective
interventionmaybeconsideredwhenpressuregradientsbyechocardiogramor
cardiaccatheterizationaresignificantlyelevated(i.e.,≥40mmHg),todecrease
theriskforcoronaryarteryatherosclerosis,damagetotheaorticvalve,left
ventriculardysfunction,andsuddendeath.
Transcatheterinterventionwithballoonandstentplacementhavebeen
