Andersons pediatric cardiology 777
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rightshunt.8
Asalreadydiscussed,severepulmonaryhypertension,andeventhe
Eisenmengerreactioncanoccurinsomepatientswithatrialseptaldefects.
Pulmonaryvascularobstructivedisease,definedasapulmonaryvascular
resistancegreaterthan7indexunits,wasfoundin5%ofpatientsinonelarge
series30andwasmuchmoreprevalentinfemales.
Althoughatrivialdegreeofright-to-leftshuntingoccursinmanyindividuals
withaninteratrialcommunication,17sufficientshuntingtoproducerecognizable
cyanosisisdistinctlyunusualinanuncomplicatedatrialdefect.Anomaliesof
systemicvenousreturnarenotcommonbutmayberesponsibleforagreater
degreeofcyanosisthanexpected.Drainageofapersistentleftsuperiorcaval
veintotheleftatriumcanbepartofadevelopmentalcomplexassociatedwithan
interatrialcommunicationattheorificeofthecoronarysinus.76Inferiorcaval
venousdrainagemaybeanatomicallyorfunctionallyanomalous,withflowto
theleftatriumortobothatria.Thismostcommonlyoccurswithaninferiortype
ofsinusvenosusdefect,sincetheinferiorcavalveinoverridestheinteratrial
septum.Ithasalsobeenreportedwithdefectsintheovalfossaextendingtothe
mouthoftheinferiorcavalvein.61
Althoughspontaneousclosureofanatrialseptaldefectislesscommonthan
spontaneousclosureofadefectintheinterventricularseptum,numerousauthors
havereportedsuchclosure,withanincidencevaryingfrom3%to67%.34,71,77–80
Thismarkedvariabilityinestimatedratesofclosureresultsfromseveralfactors.
Theincidenceishigherwhentheatrialdefectisdetectedinthefirstyearoflife,
asillustratedbytheclosurerateofmorethanhalfinoneseries.77Another
importantfactoristhatascertainmentofatrialshuntshasbeendramatically
increasedinrecentyearsbytheremarkablesensitivityofDopplerandcrosssectionalechocardiography.71Undoubtedlymanyoftheseatrialshuntsdetected
inearlyinfancyresultfromtransientincompetenceoftheflapoftheovalfossa
andshouldbeconsiderednormalvariants.
Atrialarrhythmiasarerelativelyuncommoninchildrenwithatrialseptal
defects,buttheytendtobecomemorecommonwithadvancing
age.28,32,37,38,81,82Atrialflutterorfibrillationoccursfrequentlyinolder
individuals,withalargeleft-to-rightshuntandanenlargedrightatriumbeing
foundin66%ofpatientsinoneseries.37
Rarely,paradoxicembolismmayoccur,withaclotfromapelvicorlegvein
crossingthedefectandenteringthesystemiccirculation.Asdiscussedearlier,a
smallright-to-leftshuntisnotuncommoninpatientswithanatrialseptaldefect.
ThismaybeaugmentedduringaValsalvamaneuverorsimilaractivitysuchas
strainingatstool.Otherstudieshaveshownthatpatencyoftheovalforamen,
evenwithoutanatrialshunt,maybeariskfactorforstrokesinyoungadults.83,84
Infectiousendocarditisisaveryrarecomplicationofanatrialseptaldefect
unlessthereisapredisposingassociatedanomaly.9
Studiesofnaturalhistoryinpatientswithatrialseptaldefectswhohavenot
undergonesurgicalcorrectionsuggestanaveragelifeexpectancybetween36
and49years,withthree-quartersofpatientsdyingbeforeage50yearsandninetenthsby60years.28,37,85,86Longevity,however,wasmuchgreaterinthe
absenceofpulmonaryhypertension.87Becausethedatafromthesestudieswere
largelygatheredinanerawhenassociatedrheumaticmitralvalvardiseasewas
morecommon,theyprobablydonotaccuratelyreflectthecurrentlife
expectancyofanindividualwithanisolatedatrialseptaldefect.Inamorerecent
study,amorebenignnaturalhistorywasdescribedinminimallysymptomatic
patientswhopresentedafter25yearsofage,withfindingsinthisstudy
equivalenttotheresultsfromasimilargroupofpatientswhounderwentsurgical
repairinadulthood.88Nonetheless,giventhelikelyprogressionofdisease,with
theconsequentburdenoflatemorbidityandmortality,closureofmostdefectsis
recommendedwhentheyareassociatedwithdemonstrablerightheartvolume
overload.
Management
Althoughitispossibletoperformwithalowrisk,closureofanovalfossadefect
inearlychildhoodisnotusuallyperformed.Thisisbecauseseveralstudieshave
shownthatmanyofthesechildrenwillhavespontaneousclosureofthe
defect.34–36,77,89However,closurebeforetheageof6yearsisusuallysuggested
whenthereisdemonstrablerightheartdilation.Sometimesclosureisassociated
withimprovedstaminaandagrowthspurt,evenin“asymptomatic”patients.90
Thereisrarelyanyurgency,however,anddelaymaybereasonableif,for
example,theabilitytoperformtheprocedurewithatranscatheterdevicewould
beimprovedwithsomaticgrowth.Indeed,thereisasafeagewindowofmany
yearsorevendecades,betweenwhichthereisnolikelyaccruedlong-termrisk
oflatermorbidity.Theonlyexceptiontothisiswhenassociatedpulmonary
hypertensiondevelops.Whenclosurewasachievedonlybysurgery,high
operativemortalityanddecreasedlifeexpectancywerereportedforpatientswho
underwentrepairinthefaceofpulmonaryvasculardisease.87Onamore
optimisticnoteforthisgroupofpatients,areviewmorereflectiveofthemodern
surgicalerademonstratedalowperioperativemortalityrateandimproved
prognosisinsurgicallyversusmedicallytreatedpatientswithtotalpulmonary
vascularresistancebetween7and15indexunits.30Evenmorerecently,there
havebeenreportsofclosureaftertreatmentoftheelevatedpulmonaryvascular
resistancewithspecificpulmonaryvasodilatortherapysuchasbosentan.91The
long-termoutcomesunderthesecircumstancesarelesswellknown,butrecent
reportssuggestafurtherfallinelevatedpulmonaryvascularresistance(PVR)
afterrepair.Indeed,inarecentfollow-upstudyof17patientswithamean
preoperativePVRofover9indexedWoodunits,thePVRfelltoanaverageof
justover6indexedWoodunitsapproximately2yearsaftersurgery.Nonetheless,
11patientshadapersistentelevationofPVRofover3Woodunits,andit
remainstobeseenwhethertheirlonger-termoutcomeswillbesatisfactoryor
superiortonooperation.92Clearlyeachpatientmustbetakenonhisorher
meritsandcarefulevaluationisneeded.
SurgicalClosure
Open-heartrepairofinteratrialcommunicationshasbeencarriedoutwith
