Andersons pediatric cardiology 1925

FIG.73.27 Kaplan-Meiersurvivalcurvedemonstrating5-yearsurvivalin
eachgroup.Survivalofpatientswithvenovenouscollateralsundergoing
embolizationwasonly74%comparedwith92%inthosepatientswhodid
nothaveembolization.VVC,Venovenouscollaterall.(FromPoteruchaJT,
JohnsonJN,TaggartNW,etal.Embolizationofveno-venouscollaterals
aftertheFontanoperationisassociatedwithdecreasedsurvival.Congenit
HeartDis.2015;10:E230–E236.)

AortopulmonaryCollateralEmbolization
Aortopulmonarycollateralvesselsmakeasignificantcontributiontocardiac
outputandeffectivepulmonarybloodflowintheFontancirculation.347,348The
magnitudeofthiscontributionmayinverselyrelatedtopulmonaryarterysize.356
Thisportionofcardiacoutputisrecirculatedthroughthepulmonarycirculation
andpresentsavolumeloadtothesystemicventricle.Nevertheless,somehave
postulatedthataortopulmonarycollateralflowmaybebeneficialbecauseit
providesadegreeofpulsatilitytopulmonaryflowwithabeneficialeffecton
endothelialfunction.ItmayalsoreducetheriskofpulmonaryAVmalformations
byprovidingasourceof“hepaticfactor”toalungthatreceiveslittleflowfrom
theinferiorvenacava.Coilocclusionofthesevesselsisrarelyindicatedoutside
theimmediatepostoperativeperiod,exceptintheoccasionalpatientwith
increasedvolumeloadandatrioventricularvalveregurgitationordeteriorating
ventricularfunction.ThissmallsubsetofpatientshasahighriskofFontan
failure;inonereport,morethanathirdofpatientswhounderwentcoilocclusion


ofaortopulmonarycollateralsaftertheFontanprocedureweresubsequently
transplantedordied.357


ManagementofFontanFailure
Definitions

Fontanfailurecanbelooselydefinedasaclinicalsyndromeinwhichthe
circulationcannolongermeetthemetabolicdemandsofthebody.Althoughthis
definitionissimilartothatofheartfailure,358thereareimportantdifferences.
Fontanfailureisaheterogeneoussyndromethatinvolvesmultipleorgan
systems.ThechronicelevationofCVPandthelackofpulsatilitywithinthe
pulmonarycirculationareassociatedwithgradualandprogressivepathologic
changesthatinvolvetheentirebodyinvaryingdegreesofseverityandin
varyingcombinations.Thustheinterplaybetweentheorgansystemsbecomes
derangedinamultitudeofwaysthatdifferbetweenpatients(Table73.4).There
arenotabledifferencesinFontanfailurebetweenadultsandchildren,with
ventriculardysfunctionbeingamoreprominentfeatureinchildrenandorgan
systemdysfunctionbeingamoreprominentfeatureinadults.Thesedifferences
maybeexplainedbytheobservationthatchildrenwithadequateventricular
functionaremorelikelytosurvivetoadulthoodandgoontodeveloptheorgan
systemcomplicationsoftheFontancirculation.71,359
Table73.4
OrganSystemDiseaseProcessesAssociatedWiththeFontanCirculation
OrganSystem
Lungs

Liver

Kidneys
Heart

Pulmonaryvascularremodelingandincreasedpulmonaryvascularresistance(unrestricted
bloodflowininfancy,passivenonpulsatileflow)
Decreasedpulmonaryvascularcapacitanceendothelialdysfunction,aortopulmonary
collateralsduetothelackofhepaticfluentand/orthelossofpulsatility
Hepatopulmonarysyndromeandportopulmonaryhypertension

Restrictivelungdisease(developmental,priorchestsurgeries,cardiomegaly,abnormal
alveolization,andsecondarytopulmonaryvascularabnormalities)
Plasticbronchitis
Sinusoffibrosis,centrilobularnecrosis,andhepaticcirrhosiswithincreasedriskof
hepatocellularcarcinoma
Withincreasingportalveinhypertension,thehepaticarterialbufferreflexpreserveshepatic
perfusionbywayofdilatingsplanchnicandsystemiccirculationsandreducingthesystemic
vascularresistance
Reducedrenalperfusionasaresultofreducedcardiacoutputand/orrenalcongestion
Cardiorenalsyndrome
Arrhythmias
Systolicdysfunction
Diastolicdysfunction