Andersons pediatric cardiology 751
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however,somecentersreportusingpulmonaryarterialhypertensivemedications.
Thereareexperimentaltherapiesbeingtrialedatinstitutionswiththegoalof
slowingtheprogressionofthediseasebytargetingpathwaysthoughttobe
activatedintheunderlyingpathophysiology.Basedonimmunohistochemistryof
humanspecimens,receptortyrosinekinaseinhibitorsandotherantiproliferative
agentsarebeingevaluatedinaclinicaltrial.201Publishedresultsofthesinglearmtrialdemonstrateasurvivalof77%at72weeks.201aTheuseofexperimental
animalmodelshasidentifiedapotentialroleofTGF-βendothelial-tomesenchymaltransitionintheprogressionofPVS,resultinginatrialevaluating
theroleoflosartaninpatientswithPVS.202
Catheter-BasedInterventions
Althoughcatheter-basedinterventionsusingstentsandcuttingballoonshave
beensuccessfulinadultswithPVSoccurringaftercatheterablationforatrial
fibrillation,203–205thelong-termresultsforcatheter-basedtreatmentofother
causesofPVShavebeendisappointingowingtohighratesofrestenosis.206–208
Pengetal.reportedafreedomfromreinterventionof15%at1yearforballoon
angioplasty,209whereasBalasubramanianetal.demonstratedafreedomfrom
reinterventionof37%at1yearforchildrenwhoreceivedanendovascular
stent.210Arecentsmallseriespublishedencouragingresultsofdrug-eluting
stentsinmaintainingveinpatencyinchildrenwithPVS.211Althoughthedata
suggestthatcatheter-basedinterventionsmaynotbedurableinthemajorityof
childrenwithPVS,thereisanimportantroleforcatheter-basedinterventionsto
bridgechildrentolungtransplant,tooptimizepatientsforsubsequentpulmonary
veinsurgery,andforsymptommanagementinpalliatedpatients.Currently,new
toolssuchasdrug-elutingandbioabsorbablestentsanddrug-coatedballoons
mayprovidemoredurablesolutions.
Surgery
Surgicalinterventioncanbestaddressstenosisthatoccursclosetothevenoatrial
junctionpriortothefirst-orderbranches.Conventionalsurgicalapproacheshave
includedpatchgraftingwithexcisionofanobstructinglesionatthejunctionof
thepulmonaryveinwiththeleftatrium212,213;however,recurrenceofdiseaseis
common.IntroductionofthesuturelesstechniqueforpostrepairPVSshowed
promisingresultscomparedtoconventionalsurgicalapproachesforPVS.199The
suturelesstechnique(describedinthesectionTotallyAnomalousPulmonary
VenousConnection)hasimprovedfreedomfromreoperationanddeath
comparedwithtraditionalsurgicaltechniques.Thesuturelesstechniqueisa
commonlyusedsurgicalrepairforprimaryandpostrepairPVS;However,
diseaseprogressionisstillcommon,especiallyintheintraparenchymalveins
outsidethereachofasuturelessrepair.Useofamultimodalapproachinvolving
surgery,catheter-basedinterventions,andexperimentaltherapieslikelywill
affectsurvivalofthesechildren.
Forchildrenpresentingwithunilateralpulmonaryveinatresiaorsevere
hypoplasiaandhemoptysis,pneumonectomyisaneffectivetreatmentbutalso
associatedwithconsiderablemorbidityandmortality.187,191
LungTransplant
Forchildrenpresentingwithprogressiveend-stagePVS,lungtransplantcanbe
anappropriatetherapy.Althoughwaitinglistmortalitycanbehighowingtothe
scarcityofdonororgansandtherearelimitedlong-termmechanicalsupport
optionsforchildrenweighinglessthan15kg,lungtransplantshouldbe
consideredinpatientswithrefractoryPVS.Inrareinstances,aheart-lung
transplantmaybeanoption.Oneofthelargestseriesofpediatriclung
transplantsincluded20childrenwithPVSandreportedoverall5-yearsurvival
of67.3%forcongenitalPVSand50.7%forthosechildrenwithacquired
PVS.214,215Mechanicalsupportusingapulmonary-artery-to-left-atrium
configurationwithalow-resistanceoxygenatorhasbeendescribed.216Lung
transplantation,therefore,shouldbeconsideredinchildrenwithend-stagePVS.
Summary
ProgressivePVSisararediseaseassociatedwithhighmorbidityandmortality.
Clinicalprogressioncanbesilentandrequiresvigilantsurveillance.Treatment
includescatheter-basedinterventionsandsurgery;however,2-yearsurvivalis
approximately55%to60%.Newstrategiesforcatheter-basedinterventionsand
medicaltherapiesarebeingevaluated.Lungtransplantisaviableoptionfor
childrenwithend-stagedisease.
PulmonaryVarix
Pulmonaryvarixisarareanomaly,presentingasamassinthelungonroutine
chestradiography,usuallybetweenthefourthandsixthdecades.Ithasbeen
foundinpatientsasyoungas7years.Itisusuallyobservedintherightupper
pulmonarylobe.Thedifferentialdiagnosisincludesallotherspace-occupying
lesions,butitcanbeestablishedbypulmonaryangiography,MRA,computed
tomographicangiography,217,218or―ifitisrelatedtotheheart―by
transesophagealechocardiography.219Thislesionisconsideredbenign,and
treatmentisgenerallyreservedforthosewhoexperiencecomplicationssuchas
hemoptysisorcerebralemboliceventsorforthoseinwhomgrowthofthedefect
resultsincompressionofsurroundingstructures.220Deathcausedbyrupturehas
beenreported.221–223
