455 LEFT VERSUS RIGHT INTRA-ABDOMINAL UMBILICAL ARTERIES:A COMPARISON OF THEIR DOPPLER WAVEFORMS SUSAN JANECZEK1,WILLIAM MACMILLAN2, RICHARD BESINGER2, ELIZABETH WEISEN-BORN2, ROBERT MITTENDORF2, 1UMDNJ-Robert Wood Johnson MedicalSchool/Robert Wood Johnson University Hospital, Obstetrics & Gynecology,New Brunswick, NJ 2Loyola University of Chicago, Obstetrics & Gynecology,Maywood, IL

OBJECTIVE: To compare Doppler velocimetry between the left and rightintra-abdominal umbilical arteries to each other and to a free loop of umbilicalcord.

STUDY DESIGN: In this prospective study, consenting patients with non-anomalous, singleton gestations were enrolled between 24 and 41 completedweeks. Each fetus was sampled only once. The intra-abdominal segment of theleft umbilical artery was discriminated from the right in a transverse sonographicview of the fetal abdomen at the level of the bladder. The systolic-to-diastolic (S/D) ratio, resistance index (RI), and pulsatility index (PI) were measured lateralto the fetal bladder. Measurements from at least three cardiac cycles wereobtained and averaged from both anatomic locations. Three sets ofmeasurements were also obtained from random free loops of umbilical cord.

RESULTS: 252 patients were enrolled. The S/D ratio of the intra-abdominalsegment of the left umbilical artery was found to be greater than that of the rightwith a mean difference of 0.14 (Student’s paired t-test, P < .025). The PI was alsofound to differ (P < .007) with a mean difference of 0.09 (left-greater-than-right). No difference between the RI of the two vessels was found. The presenceof diabetes or hypertension did not affect the Doppler measurements. Allparameters, when measured intra-abdominally, were elevated (P < 0.0001),when compared to those obtained from free loops of umbilical cord. Two fetuses(0.8%) demonstrated disparate blood flow measurements between the left andright umbilical arteries with one artery demonstrating absent end diastolic flow.

CONCLUSION: These data show for the first time that location of theumbilical artery, whether on the left or right side of the fetus, appears toinfluence some blood flow parameters. All intra-abdominal parameters areelevated as compared to those obtained from a free loop of cord. Thesignificance of highly disparate values, when found, warrants further in-vestigation.

456

457 DOES MIDDLE CEREBRAL ARTERY PEAK SYSTOLIC VELOCITYDIAGNOSE ANEMIA IN FETAL NON-IMMUNE HYDROPS? MARIASEGATA1, LAURA DETTI1, ERICH COSMI2, RAY O. BAHADO-SINGH1,GIANCARLO MARI1, 1University of Cincinnati, Obstetrics and Gynecology,Cincinnati, OH 2University of Sassari, Obstetrics and Gynecology, Sassari, Italy

OBJECTIVE: An increased middle cerebral artery peak systolic velocity(MCA-PSV) diagnoses fetal anemia in red cell alloimmunization as well as inparvovirus infection. This study was undertaken to assess the feasibility of theMCA-PSV in the detection of fetal anemia in pregnancies complicated by non-immune hydrops.

STUDY DESIGN: Doppler measurements of the middle cerebral arterypeak systolic velocity were performed in 23 fetuses with non-immune hydrops.All fetuses also underwent a complete work up for searching the cause of thehydrops. Hemoglobin and MCA-PSV values were expressed as multiples of themedian (MoM). We obtained the sensitivity, specificity, positive and negativepredictive values for the MCA-PSV, with the test status being above or below 1.50MoM and the outcome status being presence or absence of severe anemiadefined as hemoglobin >0.55MoM

RESULTS: Gestational age at study entry ranged from 18 to 32.2 weeks. In 9fetuses (Group A) MCA-PSV was below 1.50 MoM and none of fetuses wasanemic. In the remaining 14 fetuses (Group B) MCA-PSV was above 1.50 MoMand all of them were severely anemic (hemoglobin ranged from 1.5 g/dL to 5.5g/dL). The sensitivity was 100%; specificity was 100%; positive predictive valuewas 100%, and negative predictive value was 100%.

CONCLUSION: MCA-PSV value is a strong predictor of non-immune fetalanemia leading to hydrops; Doppler investigation identifies patients who willbenefit from urgent intrauterine transfusion and avoid unnecessary invasiveprocedures in non-anemic fetuses. MCA-PSV should be a routine part of thework-up for non-immune hydrops.

458 CHANGES IN DOPPLER WAVEFORM OF DUCTUS VENOSUS: A COMPAR-ISON BETWEEN INTRAUTERINE GROWTH RESTRICTION AND CARDI-OPATHIES MARIA BELLOTTI1, CAMILLA DE GASPERI1, ILARIA ZUCCA1,GILDA ZECCA2, GIULIA ROGNONI2, HENRY GALAN3, GIANCARLOPENNATI4, 1University of Milan, Italy, Ob Gyn, Milano, Italy 2university ofMilan, Ob Gyn, Milan, Italy 3University of Colorado, Ob Gyn, Denver, CO4University of Milan, Politecnico di Milano, Milan, Italy

OBJECTIVE: To analyze, in fetal growth restricted (FGR) fetuses and infetuses affected by congenital heart disease (CHD) with increased right atriumpreload, the correlation between the reduction of a-wave and the ductal flow,and to verify if the increase in DVIndex could be explained by ductal dilatationrather than higher atrial pressure.

STUDY DESIGN: 56 pregnancies complicated by FGR and 17 fetusesaffected by CHD (right outflow obstruction, left heart hypoplasia) wereconsidered in this cross-sectional study. Gestational age at delivery was notdifferent between the two groups. Ductal isthmical diameter and DVIndex wasevaluated (DVI = (S-a)/S). DV flow at the isthmus was calculated according tothe validated formula. Left and right cardiac output were calculated inascending aorta and pulmonary artery. These parameters were compared withour reference values at the same gestational age.

RESULTS: DVI was significantly increased in FGR and in CHD fetuses(p < 0.01) compared to normal values. Ductal diameters were significantly widerin FGR than in normal fetuses (p < 0.001). No significant differences in ductaldiameters was found between CHD fetuses and normal (p = n.s.). Ductal flowwas maintained within normal ranges in FGR whereas CHD fetuses showeda decreased ductal flow in comparison with normal values.

CONCLUSION: In FGR fetuses the left cardiac output was maintainedwithin normal ranges, documenting a normal myocardial function. On thecontrary, the changes in DV Index observed in CHD fetuses associated withreduced forward ductal flow to the right atrium, well correlate with increasedright atrial pressure occurring in right outflow tract obstruction. In fetuses with

Volume 189, Number 6Am J Obstet Gynecol

SMFM Abstracts S185

SOLUBLE FLT1 AND ABNORMAL UTERINE ARTERY DOPPLER VELOC-IMETRY IN THE SECOND TRIMESTER PETER MULLER1, BRYANYONISH1, AMY MURTHA1, GUSTAAF DEKKER2, 1Duke University, Divisionof Maternal-Fetal Medicine, Durham, NC 2Adelaide University, MaternalMedicine, Adelaide, South Australia, Australia

OBJECTIVE: Vascular endothelial growth factor (VEGF) and normaluterine artery Doppler (UAD) velocimetry have been associated with thenormal vascular remodeling of the spiral arteries in early pregnancy. SolubleFlt1,an antagonist of VEGF, has been shown to be upregulated in patients withpreeclampsia. The purpose of this study was to compare soluble Flt1 levels inwomen with abnormal versus normal uterine artery Doppler velocimetry in thesecond trimester.

STUDY DESIGN: A prospective cohort of women 16 to 24 weeks estimatedgestational age (EGA), with singleton pregnancies, underwent UAD velocimetryand phlebotomy. Abnormal UAD velocimetry was defined as bilateral notcheswith mean resistance index (RI) of > 0.55, unilateral notch with mean RIof > 0.65, or mean RI of > 0.70. Maternal soluble Flt1 was measured by ELISA insamples fromwomenwith abnormalUADand a control groupwith normalUADvelocimetry, determined by a stratified random sample controlled for EGA.Mann-Whitney Rank-Sum test was used to compare the population of solubleFlt1 of abnormal UAD with control (normal UAD).

RESULTS: There were 169 study subjects, 30 with abnormal UADvelocimetry (18%) and 30 controls. Mean EGA of subjects in each group was18.0 weeks. Mann-Whitney Rank-sum test (P = 0.36) suggested that there is nodifference in the disrtributions in soluble Flt1 for abnormal UAD (median 0.78ng/ml, 0.28-3.2 ng/ml) vs control (median 0.72 ng/ml, 0.22-1.98 ng/ml).

CONCLUSION: Concentrations of maternal soluble Flt1 in the secondtrimester are not elevated in women with abnormal UAD velocimetry. SolubleFlt1 may not be involved in interfering with the normal early vascularremodeling of spiral arteries.

increased DVI the measurements of ductal diameter and ductal flow coulddifferentiate between a compensatory mechanism of ductal dilatation andincreased right atrial pressure subsequent to cardiac impairment.