Andersons pediatric cardiology 1926

Chamberdilation
Cirrhoticcardiomyopathy
Cyanosis
Valvarheartdisease
Shunts:Intracardiac(baffleleaks)anextracardiac(atrioventricularcollateralsand
venovenouscollaterals)
Thrombiandcardioembolicevents
Peripheral
Elevationincentralandperipheralvenouspressure
veins
Varicoseveins
Neurologic
Increasedriskofcerebrovasculareventsincludingischemicandhemorrhagicstrokes
Reducedexecutivefunctioningskills
Sleep-disorderedbreathing
Lymphatics
Impairedlymphaticcirculation
Proteinlosingenteropathy
Plasticbronchitis
Metabolic
Increasedriskofobesityanddeconditioning
Hematologic
Erythrocytosis(duetocyanosis)
Thrombocytopenia(duetocyanosisand/orportalhypertension)
Gastrointestinal
Gastroesophagealvaricesandriskofbleeding
Diarrheaandproteinlosingenteropathy
Reproductive
Increasedmaternalandfetalrisksofpregnancy

FontanFailurePhenotypicClassification

BecauseofthephenotypicheterogeneityofFontanfailureandthecomplexityof
theinteractionofthecardiovascularsystemwithotherorgans,aclassification
systemhasbeenproposed360basedonhemodynamicphenotypesofFontan
failure(Table73.5).Arrhythmias,valvardisease,andobstructionswithinthe
FontanorpulmonaryarteriesshouldbeexcludedascausesofFontanfailure
beforeassigningaphenotype.ThesepotentiallyreversiblecausesofFontan
failureshouldbeprioritizedinthetreatmentstrategy.Arrhythmiasshouldbe
treatedwithrestorationofsinusrhythmordevicetherapy,ifindicated.Any
valvarorobstructivelesionsshouldbetreatedpercutaneouslyand/orsurgically
dependingontheclinicalcircumstances(Videos73.7,73.8and73.9).358,361
DespitetheoverlapbetweentheseFontanfailurephenotypes,thisclassification
isusefultoguidetherapybasedonthepredominantpathophysiology.
Table73.5
FontanFailurePhenotypicClassification
TypeI
TypeII
TypeIII
TypeIV

Fontanfailurewithreducedsystemicventricleejectionfraction
Fontanfailurewithpreservedsystemicventricleejectionfraction
Fontanfailurewithnormalpressures
Fontanfailurewithabnormallymphatics


TypeI:FontanFailureWithReducedSystemic
VentricleEjectionFraction
Thisphenotypeisthemostcommoninchildrenandmoreoftenassociatedwith
non–leftventriclemorphology.Clinicalfeaturesmayincludepulmonaryvenous
congestion,hepaticcongestion,ascites,andperipheraledema.ElevatedCVPcan

leadtothecreationofvenovenouscollateralsandcyanosis.Thromboembolic
eventsandarrhythmiasarealsocommoninthisphenotype.Becauseofthe
neurohormonalactivationassociatedwithsystolicdysfunction,treatment
strategyissimilartothatofacquiredcardiomyopathyandheartfailure.βBlockers,ACEinhibitors,angiotensinreceptorblockers(ARBs),and
aldosteroneantagonists,inadditiontoneweragentssuchtheangiotensin
receptor–neprilysininhibitor(valsartan/sacubitril),havebeenshowntoimprove
mortalityinlargeclinicaltrialsinadultswithacquiredleftventriclesystolic
heartfailure.362–373Cautionisadvisedwhenattemptingtoextrapolatefrom
thesedataforthetreatmentofpatientswithafunctionallyuniventricularheart
whohaveundergonewithFontanfailurebecausethereislittleinformation
demonstratingtheefficacyofthesetherapiesintheFontan
population.248,306–308,320Loopdiureticsandaldosteroneantagonistsare
commonlyusedtorelievecongestionandforsymptomaticimprovement,while
monitoringrenalfunctionandelectrolytes.β-Blockersarealsousedinthese
patientstohelpimproveventricularremodelingandsystolicfunction,inaddition
totheirroleinarrhythmicsuppression.Todate,carvedilol,metoprololsuccinate,
andbisoprololaretheonlyβ-blockerswithprovenbenefitinsystolicheart
failureandshouldbeusedinfirst-linetherapy,whenpossible.β-Blockersshould
generallybeusedwithcautioninthepresenceofbradycardiaorconduction
abnormalities.ACEinhibitorsandARBsarealsoused,particularlyinthe
pediatricpopulation.However,thesemedicationscanresultinexcessive
vasodilation,especiallyifthereiscirrhosisandportalhypertension.Similarly,
angiotensinreceptor–neprilysininhibitorscancauseexcessivevasodilationand
shouldprobablybeavoidedorusedwithextremecautionuntilmoreexperience
anddataareavailable.Advancedheartfailureisanindicationforheart
transplantation,withspecialattentiontotheliverbecauseadvancedliverdisease
mayprecludeheart-onlytransplantationandnecessitateconsiderationfor
combinedheartandlivertransplantation.Leftventricleassistdevicetherapyhas
beenusedasabridgetotransplant,374andtemporarypercutaneousmechanical
supportforcardiogenicshockwiththeImpelladeviceasabridgetotransplant375

hasbeenreportedintheliterature,butexperienceislimited.

TypeII:FontanFailureWithPreservedSystemic
VentricleEjectionFraction
Thisphenotyperesemblesheartfailurewithpreservedejectionfraction.It
shouldbenotedthatnormalejectionfractionisnotsynonymouswithnormal
systolicfunction.Abnormalstrainimagingandcardiacfibrosisarecommon
featuresinthissubtype.Patientswithnormalejectionfractioncanhave
abnormalsystolicfunctionandinvariablyalsohavediastolicdysfunctionas
measuredbyechocardiography.IntheFontancirculationthesystemicventricle
pullsbloodfromthepulmonaryvasculatureduringearlydiastole.Suctionis
reliantontheprocessofactiverelaxation.Asrelaxationbecomesimpaired,
centralvenousandpulmonaryarterypressuresriseandcardiacoutputfalls.
HencethesepatientstypicallyhaveelevatedpressureintheFontanpathwayand
hepaticcongestionasaconsequenceofpulmonaryvenouscongestionand
elevatedsystemicventriclefillingpressures.AlthoughunusualinFontan
patients,coronarydiseaseshouldbeconsideredinpatientswithheartfailureand
preservedejectionfraction.Themainstayoftreatmentisreliefofpulmonary
venousandperipheralcongestionwithloopdiuretics,aldosteroneantagonist,
sodiumrestriction,andantihypertensivetherapyinhypertensivepatients.

TypeIII:FontanFailureWithNormalFontan
Pressures
Patientswiththisphenotypearesymptomaticdespiteapparentlynormalleft
ventriclesystolicanddiastolicfunction,aswellasacceptableFontanpressures.
Althoughechocardiographicmeasuresofdiastolicfunctionarehelpful,invasive
hemodynamicsareoftennecessarytodistinguishtypeIIfromtypeIII
phenotypes,withtheformerhavingelevatedventricularfillingpressuresandthe

latterhavingnormalventricularfillingpressures.Rightheartfailuresymptoms
suchasdyspnea,edema,ascites,hepatomegaly,splenomegaly,andvaricose
veinspredominateandappeartobeoutofproportiontothehemodynamics.
PulmonaryvascularchangesareinvariablyassociatedwiththeFontan
circulationandcanleadtoincreasedpulmonaryvascularresistance.However,
thecalculatedpulmonaryvascularresistancemaybeerroneouslynormaldueto
thedecompressingeffectofvenovenouscollaterals,evenintheabsenceof