Andersons pediatric cardiology 1922

heartsandcongestiveheartfailure,304,305haslittleevidencebase.Therehave
beentworandomizedcontrolledtrialsinchildrenwithafunctionally
univentricularheart:onepriortotheFontan306andonesmallerstudyafter.307
Neitherdemonstratedbenefitintermsofimprovedgrowthparameters,
ventricularfunction,306orexerciseperformance.307ACEinhibitorsare
frequentlyusedinFontanpatientswithandwithoutsystolicdysfunction,248,308
ontheassumptionthatthedevelopmentand/orprogressionofventricular
dysfunctionwillbedelayed,particularlyinthesettingofasystemicright
ventricle.Despitetheirwidespreaduse,theefficacyofACEinhibitioninthe
Fontancirculationremainsunproven,308andtheextrapolationoftreatmenteffect
frompopulationswithdifferentformsofheartfailureshouldbemadewith
caution.
AldosteroneantagonistsreducemortalitywhenusedinconjunctionwithACE
inhibitioninadultswithcongestiveheartfailureandastructurallynormal
heart.309,310Thepotentialmechanismsforthiseffectincludemodificationof
adverseremodelingbyreducinginterstitialfibrosis,andareductionintheriskof
ventriculararrhythmiaandsuddendeathduetoanincreaseinserumpotassium
levels.TheFontancirculationisassociatedwithincreasedactivationofthe
renin-angiotensin-aldosterone(RAA)system.311Thereisevidenceinchildren
withcongenitalheartdiseaseandadultswithFontanfailurethatdiastolic
ventriculardysfunctionisassociatedwithincreasedRAAsystemactivationand
withhigh-riskRAAsystemgenotypes.312,313Thereisahighprevalenceof
diastolicdysfunctioninFontanpatients,andatherapeuticroleforthese
medicationshasbeenpostulated.However,thereislittleevidenceoftherapeutic
efficacyintheFontanpopulationtodate.314
AswithACEinhibition,β-blockadecarriesamortalityandmorbiditybenefit
foradultpatientswithcongestiveheartfailureandsystolicdysfunction.315The
sameeffecthasnotbeendemonstratedinchildren,althoughstudieshavebeen
underpowered.316–319Asinglestudyinasmallgroupofchildrenandadultswith
Fontanfailureandventriculardysfunctionshowedanimprovementinejection
fractionfollowingtreatmentwithcarvedilol.320β-Blockadecanbeusefulforthe

treatmentofatrialandventriculararrhythmiaintheFontancirculation,but
carefulmonitoringisrequiredinthepresenceofheartblockandsinusnode
dysfunction.ThereisnootherindicationforitsuseintheFontanpatientwith
normalventricularfunction.
Insummary,therearefewstudiesassessingtheefficacyofthesemedications


andthosethatdoexistaregenerallysmallandoftenstatisticallyunderpowered.
AlthoughthereisnostrongevidenceintheFontansettingtosupporttheuseof
medicationsthathavebecomethemainstayofheartfailuretreatmentstrategies
intheadultswithacquiredheartdisease,thereislittletosuggestharmwhen
usedinthesettingofheartfailureaccompaniedbysystolicdysfunctioninthe
Fontanpopulation.Pediatricandcongenitalheartfailureguidelinessupporttheir
use,321–323andtheyremainpotentialoptionstoamelioratetheFontancirculation
whereevidenceofovertsystolicdysfunctionisfound.324–326Thereiscurrently
noevidencetosuggestthesemedicationsprovideaprotectiveeffectinpatients
withnormalventricularfunctiondespitetheirnotinfrequentuseinthiscontext.

Exercise
Reducedexerciseparticipationandphysicaldeconditioningarecommoninthe
Fontanpopulation.Theetiologyiscomplex,inpartrelatedtothedecreased
exercisecapacitybutalsotoperceptionsofphysicalabilityandthepsychosocial
reactiontolivingwithchronicdisease.Inactivityisthoughtlargelyresponsible
forthereducedbonedensityandmusclemassreportedinFontan
patients,11,89,156,327althoughmedicationuse,especiallydiureticsand
antithrombotictreatment,mayalsocontribute.Thesefactorsareincreasingly
recognizedashavingadetrimentalimpactonexercisecapacity.89,328–332Recent
studieshavedemonstratedthatnotonlyisexercisesafeforFontanpatients,
especiallyatsubmaximallevels,butexercisemaybeevenmoreimportantasa
therapeuticentitybecauseitcompensatesforthelackofapulmonarypumpand

mayimprovechronotropicincompetenceandrespiratoryreserve.66,78,333–335
Althoughexerciseasatherapyisstillinitsinfancy,itisgenerallyacknowledged
thatencouragingregularexercisetopromotecardiorespiratoryfitnessand
muscleconditioningshouldberecommendedaspartoflong-termFontancare,
withtheaimofpreservingorenhancingfunctionalcapacity.78,333,335–337

BirthControl
DespiteahighincidenceofinfertilityinwomenwithaFontancirculation,there
areanincreasingnumberofreportsofsuccessfulpregnancies.338–342If
pregnancyisconsidered,prepregnancycounselingandcarefulplanningensure
thatrisksareunderstoodandmitigatedasfarasispossible.250,253,343–345
UnintendedpregnancyinwomenwithaFontancirculationcarriesasignificant


risktothefetusandmother.340Forthefetus,theriskincludesexposureto
medicationsthatarepotentialteratogensandplacentaldysfunctionasa
consequenceoftheFontancirculation.Thelatterismanifestinhighratesof
miscarriageandintrauterinegrowthretardation.Riskstothemotherincludea
limitedabilitytoincreasecardiacoutput,anincreasedriskofarrhythmia,
progressionofventricularimpairment,andahypercoagulablestate.339–342
Sexualhealthanddiscussionrelatedtopregnancyriskshouldbeundertakenat
anearlystage—ideallybeforesexualmaturityisreached.345Therearemultiple
potentialcontraceptionmethodsforwomenwithaFontancirculation(Table
73.3).Preparationscontainingestrogenarenotrecommended,duetotheir
prothromboticrisk.341,342,344,345Therearemultipleprogesterone-onlyoptions
forwomen,includingtablet,implantation,andlong-actingintramuscular
injection;however,sideeffectsandalimitedwindowformisseddoseswith
someoralforms,makethesemedicationslessappealingforsomewomen.342,345
Intrauterinedevicesarenotcontraindicated,butrecognitionofthepotentialfor
severevagalresponseduringinsertionneedstobetakenintoaccount,asdoes

theriskofinfection.Thelatterishighestatthetimeofinsertionandthenfallsto
thebackgroundrateofsexuallytransmissibleinfection.341,342,345,346Simple
barrierprotectionmethodscanalsobeused,butrelianceontheseastheonly
contraceptionmethodcarriesahigherriskofcontraceptionfailureevenwith
reliableuse.345
Table73.3
ContraceptionMethodsandRecommendationsinWomenWitha
FontanCirculation
Typeof
Contraception
Abstinence
Combined
estrogen/progesterone
pill
Progesterone-only
pill

Benefits

Risks

Nointeractions

Reliesonabsolute
compliance
Thrombogenic
Interactswithwarfarin
Dependentondaily
compliance
Sideeffects,especially

menstrualirregularity
Someonly3hwindow
ofcoverformisseddose
Formulationvariationin
overallefficacy
Dependentondaily

Highintrinsicefficacy
Longwindowofcover
formisseddose(12h)
Notthrombogenic

Recommendationin
FontanPatients
Recommended
Avoid

Recommended