Andersons pediatric cardiology 1394
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reportedinfebrilepatientstoalesserextentthaninpatientswithKawasaki
disease.80,81Thisisimportantbecause,especiallyinpatientswithincomplete
clinicalcriteria,thepresenceofcoronaryarterydilationisoftenusedtoconfirm
thediagnosis.Studieshaveshownthataz-scoreof2.5identifiedpatientswith
Kawasakidiseasewith98%specificity.
Coronaryarteryaneurysmsarethemostseriouslong-termcomplicationofthe
disease.Long-termoutcomesarerelatedtotheextentofdilationofthecoronary
arteriesinthefirstmonthofillness.Theaneurysmsmaybedetectedby
echocardiographybeginning7daysafterthefirstappearanceoffever,withtheir
diameterusuallypeakingaround4weeksafteronsetoftheillness.Independent
predictorsofdevelopmenthaveincludedagelessthan1year,malegender,
Asian/PacificIslanderrace,Hispanicethnicity,delayedtreatmentwithIVIG,
persistentorrecrudescentfeverafterIVIG,andlaboratorymeasuressuggesting
worseinflammation.82–89After4to6weeks,myointimalproliferationresultsin
regressionofapproximatelyhalftotwo-thirdsofaneurysms(Fig.53.4).90,91The
likelihoodofregressionisprimarilydeterminedbythepeakluminaldiameter,
withlargeraneurysmsbeinglesslikelytoregress.92,93Otherfactorsthatpredict
agreaterlikelihoodofregressionareyoungerage,distallocation,andfusiform
shape.91Despitenormalizationoftheinternalluminaldiameter,thecoronary
arteriesarenot“normal.”Thisissupportedbypathologyspecimens47and
intravascularimaging.Intravascularultrasoundhasshownthatmyointimal
thickeningispresentmanyyearsafterdiagnosis.94–96Similarly,optical
coherencetomographyshowsintimalhyperplasia,disappearanceofthemedia,
fibrosis,calcifications,macrophageaccumulation,andneovascularization.97,98
Inadditiontopersistentstructuralabnormalities,functionalabnormalitieshave
alsobeenshown.Pharmacologictestinghasdemonstrateddecreased
vasodilation,resultinginimpairedcoronaryarteryflowreserve.96,99–101
FIG.53.4 Naturalhistoryofcoronaryarteryabnormalities.(From
NewburgerJW,TakahashiM,BurnsJC.Kawasakidisease.JAmColl
Cardiol.2016;67[14]:1738–1749.)
Patientswithpersistentaneurysmsareatriskofdevelopingsignificant
stenosissecondarytomyointimalproliferationateitherendoftheaneurysm,
calcification,tortuosity,orthromboticocclusion.Aneurysmruptureisrareand
usuallyoccursasanearlycomplication.Theincidenceofcoronarystenosis
increasesovertimeandishighestinpatientswithgiantaneurysms.90,102
TheprincipalcauseofdeathinKawasakidiseaseismyocardialinfarctionasa
resultofthromboticocclusionand/orstenosis.24Myocardialinfarctionin
childrencanbeclinicallysilentorpresentwithatypicalsymptoms.164The
highestriskisinpatientswithgiantaneurysms,wheresluggishflowincreases
theriskofthrombosis,oftencombinedwithstenosisatthedistalend.
Myocardialinfarctionismostcommoninthefirstyearfollowingdiagnosis,
althoughpatientshavealifelongincreasedriskofischemia.Indeed,previously
undiagnosedKawasakidiseasemaybecomeapparentinadulthoodattimeof
myocardialinfarction.25Fatalitiesduetomyocardialinfarctionsaremorelikely
withocclusionoftheleftmaincoronaryarteryorproximalsegmentsoftheright
andanteriordescendingcoronaries.24Thrombosisoftherightcoronaryismore
likelytobesilentandtorecanalize.Patientswithpriormyocardialinfarctionare
atriskforfurtherischemicevents,althoughtheriskcanbedecreasedwith
effectiverevascularization.103
Echocardiography
Echocardiographicimagingofthecoronaryarteriesisessentialintheevaluation
ofallpatientswithdefiniteorsuspecteddisease(Fig.53.5).Itssensitivityand
specificityforthedetectionofdilationoftheproximalcoronaryarterysegments
arehighwhenthisprocedureisperformedwithappropriatetransducersby
experiencedsonographersincooperativeorsedatedchildren.Because
aneurysmsalsooccurinchildrenwhodonotmeetclassiccriteria,
echocardiographyhasanimportantroleintheevaluationofchildrenwith
protractedfeverandsomefindingsconsistentwithfeaturesofKawasakidisease.
Additionalechocardiographicfeaturesintheacutephaseincludecoronaryartery
ectasiaandlackoftapering.Leftventricularcontractilitymayalsobe
diminished,andmildvalvarregurgitation,particularlymitralregurgitation,is
relativelycommon.66,104Althoughpericardialeffusionsmayoccur,theyare
rarelysignificantinsize.104
