Andersons pediatric cardiology 1915
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asdemonstratedbytheirlowerserumcreatinineconcentrationcomparedwith
age-matchedcontrols.Nevertheless,elevatedserumcreatinineisastrong
predictorofdeathorcardiactransplantation,whetherasanindependentvariable
oraspartoftheModelforEnd-stageLiverDiseaseExcludingINR(MELD-XI)
score.154Thedeclineinrenalfunctionisinsidiousandprotractedbutislikelyto
playanimportantroleintheprognosticationoflatesurvivors.
Fontan-AssociatedLiverDisease
Assurvivalratesfollowingstagedreconstructionhaveimproved,manypatients
arecurrentlylivingintotheirthirdandfourthdecade.Thelong-term
consequencesofelevatedCVPandlowcardiacoutputhavebecomemore
apparent.89,153,155–160AlthoughtheFontancirculationaffectsmanyorgan
systemsoutsidetheheart,itsimpactonthelivermaybethemostprevalent
complication.Despitethis,understandingoftheevolutionofliverinjuryis
limited,andtheroleofvariousscreeningtestsisonlynowevolvingasnew
informationbecomesavailable.148,158,161–164
Forchildrenwithsingle-ventriclephysiology,theinsulttotheliverprobably
beginswellbeforethecreationoftheFontancirculation(Fig.73.19).Shortly
afterbirth,infantswithfunctionallyuniventricularheartdiseasearesubjectto
oneormoresurgeriesandassociatedalterationsinhemodynamicsandoxygen
saturations.Thesederangementsmayhaveaprofoundimpactonthearchitecture
oftheliverashepatocytesaresubjectedtoimpairedperfusionandhypoxemia.
InaseriesofchildrenwhodidnotsurvivebeyondtheFontancirculation,
autopsydemonstratedtheconsistentfindingoffibrosis,confirmingthenotion
thatliverinjurybeginspriortotheFontan.165
FIG.73.19 Factorscontributingto,andconsequenceof,liverinjuryinthe
Fontanpatient.
AlthoughliverinjurymaynotstartwiththeFontanoperation,itisclearthat
additionalchangestothehepaticenvironmentarerelativelyimmediate
followingFontancompletion.Inastudyinwhichanabdominalultrasoundwas
performedjustpriortotheFontanandthenrepeated3to6monthsfollowing
totalcavopulmonaryconnection,theliverspanwasincreasedandvelocities
withinthehepaticarteriesweredecreasedaftertheFontanprocedure.162This
findingisconsistentwithhepaticcongestionand,whencoupledwithamild
elevationinliverenzymes,suggeststhatcongestionisimmediateandlikely
beginsaprocessofchroniclow-levelliverinjury.
Hepaticcongestionandtheresultantfibrosisarenotastaticprocessbutrather
onethatprogressesslowlyovertime.InastudyofadolescentswithFontan
physiology,theonlyconfirmedriskfactorforthedegreeoffibrosiswasthe
amountoftimethathadpassedsincetheinitialFontanoperation.158Although
thesamplesizewasrelativelysmall,ventricularmorphology,atrioventricular
valveregurgitation,andventricularfunctionwerenotassociatedwiththedegree
ofliverfibrosis.Interestingly,systemicvenouspressurewasnotassociatedwith
thedegreeoffibrosis.Thismayhavebeenrelatedtotherelativelynarrowrange
ofFontanpressuresofthepatientsincludedintheanalysis.Inanotherrecent
