Andersons pediatric cardiology 204
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FIG.7.13 T2mapsinafetuswithtranspositionofthegreatarteries.The
brightersignalfromthebloodintheleftventricleandmainpulmonary
artery(MPA)thanthebloodintherightventricle(RV)andaortaindicatesa
reductionintheoxygensaturationofbloodsuppliedtothedevelopingbrain
inthesettingofventriculoarterialdiscordance.AAo,Ascendingaorta;LV,
leftventricle.
CongenitalHeartDisease:Hemodynamic
Consequences
TheeffectsofCHDonfetaloxygendelivery(DO2),oxygenconsumption(VO2),
fetalcerebraloxygendelivery(CDO2),andcerebraloxygenconsumptionare
showninTables7.5and7.6.23Here,arangeofdifferentCHDtypeshavebeen
combinedintoasinglegroupandcomparedwithalargegroupofcontrol
fetuses.Toobtainbloodoxygencontentweestimatedhemoglobinconcentration
basedongestationalageappropriatereferencedataandconvertedT2tooxygen
saturation(SaO2)usingpriorexperimentsinwhichtherelationshipbetweenthe
SaO2ofadultbloodandT2wasdetermined.24,25Usingthisapproach,wefound
areductionof25%infetalDO2resultingfromdiminishedumbilicalveinflow
andoxygencontent.26ThisreductioninfetalDO2wasassociatedwitha
correspondingdropinfetalVO2.Aspreviouslydescribed,thereductioninfetal
DO2combinedwithinterruptionoftheusualstreamingofoxygenatedblood
fromtheplacentatofetalbrainwasassociatedwithanaveragereductionin
oxygensaturationof10%intheascendingaorta.Inkeepingwiththeconceptof
brain-sparingphysiologydescribedabove,thisreductioninascendingaortic
saturationwasassociatedwithanincreaseinSVCflow,althoughthiswasonly
apparentwhenSVCflowwasindexedtobrainvolume.InourstudiesoflategestationCHDfetuses,theirbrainshavebeen10%to15%smallerthanthoseof
normalcontrols,whilefetalweighthasnotbeensignificantlydifferent.When
SVCflowandCDO2areindexedtofetalweight,cerebraloxygendeliveryand
consumptionarereducedinfetuseswithCHD,whileCDO2andCVO2indexed
tofetalbrainweightarenotsignificantlydifferentbetweenfetuseswithCHD
andnormalcontrols.
Table7.5
FetalHemodynamicsinControlandCongenitalHeartDisease
FetusesbyMagneticResonanceImaging
Fetalgestationalage(weeks)
CHD(n=40)a
36.5±1.0
Normal(n=46)a
36.5±1.3
PValue
.9
Estimatedfetalweight(kg)
DO2(indexedtofetalweight)(mL/min/kg)
QUV(indexedtofetalweight)(mL/min/kg)
UVSaO2(%)
AAoSaO2(%)
SVCflow(indexedtofetalweight)(mL/min/kg)
SVCflow(indexedtofetalbrainweight)(mL/min/g)
a
3.0±0.4
15.8(13.9–20.9)
115.4±32.3
73.5(68.3–79.0)
48(40–54)
128.5(106.0–169.0)
1.41±0.08
2.9±0.4
21.0(16.4–23.7)
130.2±28.6
79.0(73.8–83.0)
58(52–64)
126.5(103.0–151.3)
1.20±0.06
.2
.003
.03
.01
<.001
.4
.03
Standarddeviationsshowninparentheses.
AAo,Ascendingaorta;SVC,superiorvenacava;QUV,umbilicalveinflow;UV,umbilicalvein.
Table7.6
FetalCerebralHemodynamicsinControlandCongenitalHeart
DiseaseFetusesbyMagneticResonanceImaging
CDO2(indexedtofetalweight)(mLO2/min/kg)
CDO2(indexedtofetalbrainweight)(mLO2/min/g)
CVO2(indexedtofetalweight)(mLO2/min/kg)
CVO2(indexedtofetalbrainweight)(mLO2/min/g)
NeonatalGA(weeks)
Neonatalbrainvolume(mL)
WMADC(mm2/s)
CHD(n=40)a
12.8(10.3–14.8)
0.14±0.01
2.8(1.5–4.1)
0.03(0.02–0.05)
39.7±1.8
344.1±42.4
1705(1634–1780)
Normal(n=46)a
14.7(11.4–17.6)
0.14±0.01
3.6(2.7–5.0)
0.03(0.02–0.05)
40.2±1.4
379.2±52.0
1572(1493–1701)†
PValue
.04
.75
.01
.17
.2
.0008
.0004
aStandarddeviationsshowninparentheses.
AAO,Ascendingaorta;CHD,congenitalheartdisease;GA,gestationalage;SVC,superiorvena
cava;UV,umbilicalvein;WMADC,whitematterapparentdiffusioncoefficient.
