Andersons pediatric cardiology 2131
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inthesecondstageoflabor—mayfurtherfacilitateright-to-leftshunting,leading
toapotentialspiralofhypoxemicpulmonaryvasoconstriction,hypotension,and
death.
Overall,thehighmortalityofpregnancyinEisenmengersyndromehas
remainedintherangeof30%.52Outcomesmaybebetterwithearlydiagnosis
andcomprehensivemanagement.Targetedadvancedpulmonaryvascular
therapiesappliedinspecializedcentersarelikelytoprovidebetteroutcomes,
althoughreportsofsuchimprovedoutcomesarelimitedandtheriskremains
high.53,54Asaconsequence,thewidelyheldconsensusistoadviseagainst
pregnancyinwomenwithsignificantpulmonaryhypertensionofanycauseand,
intheeventofunexpectedpregnancy,toofferterminationasthesafestoption.
MarfanSyndromeandOtherAortopathies
Pregnancy-relatedhemodynamicandhormonalchangesaffectthestructureof
theaorticwallandincreasetheriskofdilationanddissection.Thisphenomenon
manifestsasanincreasedriskofspontaneousdissectioneveninwomenwithno
knownordiagnosableaortopathy.Dissectionriskisverylowinotherwise
normalwomen.DissectionhasbestbeendescribedinwomenwithMarfan
syndrome,butthosewithotheraortopathiesthathavegeneticand/orpathologic
similarities—suchasfamilialthoracicaorticaneurysmanddissection
syndromes,Loeys-Dietzsyndrome,theaortopathyassociatedwithbicuspid
aorticvalve,Turnersyndrome,andvascularEhlers-Danlossyndrome—arealso
atincreasedriskofaorticcomplications.55
InaprospectivestudyofwomenwithMarfansyndromefollowedthrough45
pregnancies,nosignificantchangewasfoundinthesizeoftheaorticrootin
thoseinitiallyexhibitingrootsofnormalsize,butone-thirdofwomenwith
dilatedrootsorthosehavinghadprioraorticsurgeryexperiencedeitheraortic
dissectionorprogressiveaorticdilation.56Inasingle-centerstudy,favorable
outcomeswerereportedinalargecohortofwomencarefullyfollowed
throughoutpregnancy,althoughaorticgrowthrateincreasedduringpregnancy
anddidnotreturntobaselineafterpregnancy.57Althoughtherearenotrials
demonstratingspecificbenefitduringpregnancyofβ-adrenergic–blockingdrugs
inwomenwithaortopathy,manyexpertsrecommendsuchtreatmentduringand
afterpregnancyinwomenwithMarfansyndromeandotherhigh-risk
aortopathiesinthehopethatthismayattenuatetheriskofaorticdilationor
dissection.
ProstheticHeartValves
Womenwithanytypeofartificialheartvalveareatincreasedriskfor
complicationsduringpregnancy.Bioprostheticandmechanicalvalveseachhave
advantagesanddisadvantages.Carefulconsiderationoftherisksandbenefitsof
eachisrequiredpriortoselectionofthetypeofprostheticvalveinawomanof
childbearingage.Duringpregnancy,normallyfunctioningbioprostheticvalves
aresaferthanmechanicalvalvesbecausetheyarelessthrombogenicanddonot
requireongoinganticoagulation.Bioprostheticvalves,nonetheless,havelimited
durability,andwomenwiththesevalveswillgenerallyrequirerepeatedsurgery
inthefuture.Althoughsomestudieshavesuggestedthatpregnancyaccelerates
thedegenerationofbioprostheticvalves,othershavenotsupportedthis
finding.58–60Lessinformationisavailableonthesafetyofhomograftsduring
pregnancy,althoughonestudyfoundnovalve-relatedcomplicationsduring
pregnancy.61,62
Mechanicalvalveshavebetterdurabilitythanbioprostheticonesbutare
associatedwithsignificantlygreatermaternalandfetalrisksduringpregnancy.
Becausepregnancyisahypercoagulablestateandanticoagulationcanbe
difficulttomanagewithchangingbodyweightduringpregnancy,thereisan
increasedriskofmaternalthromboembolicevents,ofwhichapproximatelyhalf
arevalvarthrombosis.Manyfactorsinfluencetheriskofvalvethrombosisand
pooroutcomesinpregnancy.Valvesinthemitralpositioncarryhigher
thromboticrisksthanthoseintheaorticposition,asdoearlymodelsof
mechanicalvalves,suchasthosewithballsincagesorthefirstgenerationof
thosewithtiltingdiscs.However,oneofthemostimportantdeterminantsof
thrombosisriskisthetypeofanticoagulationusedduringpregnancy,as
discussedlater.Anticoagulanttherapyiscomplicatedbyriskofbleeding.
Systematicreviewshavereportedonmaternalandfetalrisksinpregnantwomen
withmechanicalvalves.63,64Risksofmaternalandfetaladverseoutcomesin
pregnantwomenwithmechanicalvalvesaccordingtotypeofanticoagulantused
inpregnancyareshowninTable80.3.63
Table80.3
MaternalandFetalAdverseOutcomesinPregnantWomenWith
MechanicalValves
Maternal
Livebirth
Anticoagulant-Related
Anticoagulation
Regimen
VitaminK
antagonists
(INRtarget
2.5–3.5)
Sequential
treatment
LMWHalone
UFHalone
Mortality
Estimate,
%(95%
CI)
0.9(0.1–1.6)
2.7(1.4–4.0)
2.0(0.8–3.1)
5.8(3.8–7.7)
2.9(0.2–5.7)
8.7(3.9–13.4)
3.4(0–7.7)
11.2(2.8–19.6)
Thromboembolism
Estimate,%(95%
CI)
Rate
Estimate,
%(95%
CI)
64.5(48.8–
80.2)
79.9(74.3–
85.6)
92.0(86.1–
98.0)
69.5(37.8–
100)
Fetal/NeonatalAdverse
Events
Estimate,%(95%CI)
2.0(0.3–3.7)a
1.4(0.3–2.5)a
NA
7.6(0.1–15.0)b
a0.8%representembryopathyand2.1%representfetopathy.
bAllcasesrepresentfetopathy.
Estimatesarepresentedasproportionsper100affectedpregnancieswith95%confidence
intervals(CI).
INR,InternationalNormalizedRatio;LMWH,low-molecular-weightheparin;NA,notapplicable;
UFH,unfractionatedheparin.
FromD'SouzaR,OstroJ,ShahPS,etal.Anticoagulationforpregnantwomenwithmechanical
heartvalves:asystematicreviewandmeta-analysis.EurHeartJ.2017;38:1509–1516.
Optionsforanticoagulationincludeunfractionatedheparin,low-molecularweightheparin,andoralanticoagulantssuchaswarfarinandadjunctiveaspirin.
Heparindoesnotcrosstheplacentaandthereforeisasaferalternativeforthe
fetus.Heparingivensubcutaneouslyisdifficulttomanage,andisalesseffective
anticoagulant,withhighermaternalthrombosisratesthanwarfarin.Valvar
thrombosis,whichcanbefatal,islesscommoninpregnancywhenoral
anticoagulantsareusedthroughoutcomparedwithoralanticoagulantswith
unfractionatedheparinsubstitutedbetween6and12weeksofgestationor
heparinthroughoutpregnancy.Heparinmayalsocausematernal
thrombocytopeniaandosteoporosis.Warfarincrossestheplacentaandis
associatedwithwarfarinembryopathyinfirst-trimesteruseandwithfetal
intracranialbleeding,whichisariskthroughoutpregnancy.Theriskofwarfarin
embryopathyhasbeenshowntobelessifheparinissubstitutedfrom6until12
weeksofgestationandalsoinwomenwhosetherapeuticdoseofwarfarinisless
than5mg/day.65Becauseintracranialbleedingcanoccurduringvaginaldelivery
inafetusexposedtomaternalwarfarin,heparinshouldbesubstitutedatleast2
weekspriortodeliveryorthefetusmustbedeliveredbycesareansection.Lowmolecular-weightheparin(LMWH)iseasiertousethanunfractionatedheparin
andhasbetterbioavailability,butitisalsoassociatedwithhigherratesof
