Andersons pediatric cardiology 1184
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FIG.44.20 Parasternallong-axisviewofatransthoracicechocardiogram
demonstratingthickenedleafletsoftheregurgitantaorticvalve.Thearrow
pointstothesiteformeasurementoftheratioofwidthofthejettothe
aorta.AO,Aorta;LA,leftatrium;LV,leftventricle.
Holodiastolicflowreversalinthedescendingaortaatthelevelofthe
diaphragmisconsistentwithatleastmoderateregurgitation(Fig.44.21).
Quantitativemethodstoassesstrueregurgitantvolume,ortheeffectiveareaof
theregurgitantorifice,areoftenusedinadultpatientsbutarenotroutinelyused
inpediatricechocardiographyduetoconcernsaboutlargerstandardoferrorand
lackofreproducibility.54Finally,theassessmentandmeasurementofleft
ventricularsizeandfunctionareessentialtotheevaluationofaorticregurgitation
andareacriticalpartofdecision-makingwithregardtotimingofintervention.
FIG.44.21 Parasternallong-axisviewwithcolorandspectralDopplerofa
transthoracicechocardiogramofapatientwithcombinedvalvarand
subvalvarstenosis(arrow)andassociatedsignificantaorticregurgitation.
Notetheholodiastolicreversalofflowintheabdominalaorta,shownin
lowerrightimage,andtheshortpressurehalftimeseenintheupperright
panel.Thelowerleftpanelshowstheanatomyoftheregurgitantjet,
revealingtheproximalisovelocitysurfacearea,thevenacontracta,andthe
proximalanddistaljets.LA,Leftatrium;LV,leftventricle.
MagneticResonanceImaging
Cardiovascularmagneticresonanceprovidesamultiplaneanalysistoquantify
thevolumeoftheleftventricleandidentifytheeccentricremodelingthatoccurs
withchronicaorticregurgitation.114Comparedwithechocardiography,cardiac
magneticresonanceimagingalsoprovidesmoreaccuratequantificationofthe
degreeofaorticregurgitation,assessmentoftheaorticroot,andevaluationofthe
aorticvalvetoassessthemechanismofdisease.
CardiopulmonaryExerciseTesting
Exercisestresstestingcanbeusedtoelicitexercise-inducedsymptomsandto
monitorforchangesinexerciseperformanceovertimeinasymptomaticpatients.
Inthesettingofaorticregurgitation,thereisalreadyarelativereductioninthe
diastoliccoronaryperfusionpressureandincreasedleftventricularend-diastolic
pressure.Duringexertion,coronaryperfusionisfurthercompromisedduetoan
increaseinmetabolicdemandandanincreaseinheartratethatdecreases
diastolicfillingtime.56Exertionalsymptomsofdyspneaoranginamaydevelop
duetoarelativemismatchofcoronarysupplyanddemandthatoccurswith
exercise.
CardiacCatheterization
Cardiaccatheterizationandangiographyhavealimitedroleinthediagnostic
evaluationofthepatientwithaorticregurgitation.Angiographicgradingof
regurgitationismostlysubjective,andleftventricularsystolicfunctionisbetter
evaluatedbyeitherechocardiographyormagneticresonanceimaging.
NaturalHistory
Therateofprogressionofaorticvalveregurgitationisvariabledependingonthe
underlyingetiology.However,ingeneral,mostpatientswithchronicaortic
regurgitationhaveaslowprogressionindegreeofregurgitationandleft
ventriculardimensions.Inasymptomaticadultswithchronicsevereaortic
regurgitation,therateofprogressiontosymptomsand/orleftventricular
dysfunctionaverages4.3%peryearandrateofsuddendeathwaslow,withan
averagemortalityrateoflessthan0.2%peryear.61
Dataonpediatricpatientswithpureaorticvalveregurgitationarelackingbut
likelyarealsoassociatedwithlowrateofcomplicationsandsuddendeath.
Nevertheless,patientswithchronicsevereaorticinsufficiencyareatriskfor
progressiveleftventriculardilationand,withoutintervention,eventualleft
ventriculardysfunctionandcongestiveheartfailure.Inthesettingofbicuspid
aorticvalve,thereisalsoriskforbacterialendocarditisandprogressive
ascendingaorticdilation,similartowhatwasdescribedpreviouslyforaortic
valvestenosis.Theaorticvalveregurgitationassociatedwithaorticrootdilation
inpatientswithcongenitalheartdisease,suchastetralogyofFallotor
transpositionofthegreatarteriesafterarterialswitchoperation,appearstobe
relativelyuncommonwithalowrateofneedforintervention.115
