Andersons pediatric cardiology 1122
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valvuloplasty(Video42.4).
FIG.42.29 Basicproceduralstagesofballoonpulmonaryvalvuloplasty
(A-planeprojectiontotheleft,lateraltotheright).Top,Baselineright
ventricularangiogramdocumentingadomingpulmonaryvalve(annulus
measuredathingepoints).Middle,Ballooninflationwithvisiblewaist
(midwaythroughinflation).Bottom,Rightventricularangiogramafter
balloondilation.
Balloonpulmonaryvalvuloplastyisusuallyperformedusingfluoroscopic
guidance,eventhoughitispossibletoperformtheprocedureunder
echocardiographicguidancealone.80However,thereisevidencethat
echocardiographicpulmonaryvalvemeasurementsaresmalleronaveragethan
angiographicmeasurements,withasignificantvariationinthisdiscrepancy;this
limitstheabilitytochoosetheappropriateballoonsizesafely.29Fluoroscopy
timesareusuallyveryshort,withresultsfromtheC3POregistrydocumenting
themedianfluoroscopytimetobe20minutes(75th/95thcentile32/68
minutes).81ThemediantotalairKermawas87,133,244,319,1781mGyfor
patientslessthan1,1to4,5to9,10to15,andabove15yearsofage,
respectively.
Accesstothecirculationismostcommonlythroughafemoralvenous
puncture.Inpatientswithproblemsofvascularaccessduetovenousthrombosis,
othertechniquescanbeemployed,includinguseofthejugular,82axillary,83or
hepatic84veins.Althoughballoonvalvuloplastycanbeperformed
percutaneouslyinpatientsweighinglessthan1.5kg,85analternativehybrid
approachmaybemoresuitableinselectedpatients,inparticularinextremely
low-weightinfantswithapoorlyfunctioninganddilatedrightventricle,in
whomapercutaneousapproachmaynotbewelltolerated.86
Rightheartcatheterizationisperformedusingeitheracurvedend-hole
catheter,suchasarightcoronarycatheteroronethatiscobrashaped,ora
balloon-tippedcatheter.Transvalvarpeak-to-peakgradientandtheright
ventricle–to–systemicarterialpressureratioarecarefullydocumented.Itis
importanttobeattentivetothepresenceofsubvalvarand/orsupravalvarstenosis
duringthehemodynamicevaluation.Thesegradientsmaybedifficultto
distinguishfromvalvargradientsusingastandardend-holecatheter,andtheuse
ofapressurewireshouldbeconsideredwhencoexistingsub-orsupravalvar
stenosisissuspected(Fig.42.30).87Theadvantageofusingapressurewireis
thattherecordingelementislocatedatsomedistancefromthedistalendofthe
wire,therebyenablingawithdrawalthroughthesupravalvar,valvar,and
subvalvarareaswhilethedistaltipofthewireisstillpositionedinthemain
