Presentation on theme: "Doppler Ultrasonography in Obstetrical Practice"— Presentation transcript:
1 Doppler Ultrasonography in Obstetrical Practice China Medical University HospitalOBS & GYN departmentChien Chung, Lee
2 Conditions That Place Fetuses at Risk for Adverse Outcomes Maternal Chronic hypertension Collagen-vascular diseases Sickle cell anemia Current substance abuse Impaired renal function Asthma Pneumonia Significant cardiac disease Seizure disorders Diabetes Acute febrile illnesses Significant anemia (hematocrit <26%Fetal Intrauterine growth restriction Congenital anomalies Fetal cardiac arrhythmias Isoimmunization Hydrops fetalis Fetal infections such as parvovirus, coxsackievirus B, syphilis, toxoplasmosisPregnancy-related Poorly controlled gestational diabetes Multiple gestations Pregnancy-induced hypertension Cholestasis of pregnancy Premature rupture of the membranes (preterm) Unexplained elevated maternal serum alpha-fetoprotein Polyhydramnios Oligohydramnios Placental abruption Abnormal placentation Postdates Unexplained stillbirth in a prior pregnancy
3 General Guidelines for Antepartum Testing IndicationInitiationFrequencyPost-term pregnancy41 weeksTwice a weekPreterm rupture of the membranesAt onsetDailyOligohydramnios26 weeks or at onsetPolyhydramnios32 weeksWeeklyClass A1 DM (well-controlled, no complications)36 weeksClass A2 and B (well-controlled, no complications)Class A or B with poor control, Class C-R28 weeksChronic or pregnancy-induced hypertension28 WeeksSteroid-dependent or poorly controlled asthmaCollagen-vascular disease including antiphospholipid antibody syndromeImpaired renal functionUncontrolled thyroid diseaseMaternal heart disease (NYHA class III or IV)Once a weekSubstance abusePrior stillbirthAt 2 weeks before prior fetal deathMultiple gestationFetal growth restrictionDecreased fetal movementAt time of complaintOnceCholestasis
4 Biophysical profile for fetal assessment in high risk pregnancies (Cochrane Methodology Review) Reviewers' conclusions: At present, there is not enough evidence from randomised trials to evaluate the use of biophysical profile as a test of fetal well-being in high risk pregnancies.Alfirevic Z, Neilson JP. In: The Cochrane Library, Issue 4, 2003.
5 Doppler ultrasound for fetal assessment in high risk pregnancies (Cochrane Methodology Review) Reviewers' conclusions: The use of Doppler ultrasound in high risk pregnancies appears to improve a number of obstetric care outcomes and appears promising in helping to reducing perinatal deaths.Neilson JP, Alfirevic Z. . In: The Cochrane Library, Issue 4, 2003.
6 Type of Doppler ultrasonography used Descriptive characteristics of randomized trials evaluating the use of Doppler ultrasonography in pregnancy included in overviewReferenceNo. of participantPerinatal deaths (%)Type of Doppler ultrasonography usedAEDV (%)Controls Prespecified primary end point with sample size calculationsTrudinger et al., 1987,l2892.1Umbilical artery, CW 4 MHz?Gestational age at deliveryMcParland and Pearce, 19885095.1Umbilical and uterine arteries, PW15.1Death before discharge from hospitalTyrell et al., 19905001.2Umbilical and uterine arteries, CW, 4 MHz, 100 hZ2.7No. of days in neonatal intensive care unit, frequency of low Apgar scoreHofmeyr et al., 19918971.3Umbilical artery, CW, 4 MHz, 50 Hz filterNot statedNewnham et al., 19915453.3Umbilical artery, CW, 280 Hz filter2.9Neonatal hospital stayBurke et al., 19924761.5Umbilical artery, CW, 4 MHz, 150 Hz filterAlmstrom et al., 19924260.7Umbilical artery, PW, 3 MHz, 100 Hz filter1.9Biljan et al., 1992674Umbilical artery, CW, 4 MHz, 100 Hz filterNo. of antenatal tests per patient, duration of antenatal stayJohnstone et al., 19932329Umbilical artery, CW, 4 MHz, Hz filter?Pattison et al., 19942126.69.4Perinatal mortalityNeales et al4675.3Umbilical artery, CW, 4 MHz6.4Nienhuis and Hoogland150S3.4Umbilical artery, PW, 50 Hz filter
7 Proportional effect of Doppler ultrasonography on number of dead babies (stillbirths and neonates) when used in high-risk pregnancies.Meta-analysis shows that clinical action guided by Doppler ultrasonography reduced the odds ratio of perinatal death by 38%
8 Effects of Doppler ultrasonography on perinatal outcomes in high-risk pregnancies. Post hoc analysis.The 16% reduction in the number of elective deliveries, 31% reduction in fetal distress in labor, and 87% reduction in hypoxic encephalopathy in the Doppler group reached statistical significance.
9 Conditions for Doppler ultrasound Pregnancies complicated by IUGRPregnancies in which the fetus is at risk for anemiaMultiple gestationsPregnancies treated with prostaglandin inhibitors to monitor the ductus arteriosusFetal echocardiograms
11 Doppler Flow Velocity in the First Trimester Comparison of endometrial thickness, RI, & gestational age between groupsRetained tissueNot retained tissuePGestational age10.0(3.3)7.6(2.0)0.001Endometrial thickness(mm)19.5(1.8)10.2(7.0)RI0.38(0.16)0.59(0.12)Alcazar JL, Ortiz CA. Eur J Obstet Gynecol Reprod Biol Apr 10;102(1):83-7.
12 Doppler Flow Velocity in Uterine Artery Resistance falls and notching is lost on the placental side first, and asymmetry may remain until term. If notching persists contralaterally, there may be relative placental deficiency, but the ipsilateral uterine artery is more reliable.Bewley et. al.Br J Obstet Gynaecol 1989;96:1040–6
13 Successful placental invasion removes intimal muscle and renders vessels with minimal resistance, no elastic property, and vigorous diastolic flow . In successful pregnancies, Doppler studies show that this remodelling is rapid, with the loss of notching by 12 weeks and low resistance indices by 20 weeks or sooner
14 Normal midtrimester uterine artery, increased diastolic flow. Normal uterine artery at 12 weeks shows relatively high resistance, absent notching.Normal midtrimester uterine artery, increased diastolic flow.Normal third trimester uterine artery, very low resistance.High resistance with persistent notching may be normal in first trimester, not in this 24-week gestation.Very high resistance, marked notching, absent diastolic velocities in a woman with pre-eclampsia, and severe intrauterine growth restriction (IUGR) at 28 weeks.abnormal placentation is already determined by 20 weeks in worst cases; persistent notching is the best discriminatorthere is a graded relationship between the severity of notching and the severity of complicationscreening women at high risk (thrombophilia, hypertension, past history of either pre-eclampsia or IUGR) at weeks, using bilateral notching to initiate low-dose aspirin therapy, is highly effective; a significant reduction in rates of all hypertensive disorders and fetal complications included an 80% reduction in proteinuric pre-eclampsia 4.7 versus 23.3% in placebo-treated controls
15 Doppler Flow Velocity in Umbilical Artery Normal umbilical artery at 18 weeks shows relatively high resistance, but consistent diastolic flow.Normal umbilical artery at 36 weeks, low resistance, generous diastolic flow.High resistance, diastolic velocity low.Absent end-diastolic velocity (AEDV).Reversed diastolic velocity (REDV) in severe intrauterine growth restriction (IUGR).
16 Doppler Flow Velocity in Umbilical Artery Fetuses with absent end-diastolic velocity of the umbilical artery all died in utero within 3 weeks (median 7 days).Madazli R, Uludag S, Ocak V.Acta Obstet Gynecol Scand 2001; 80:702With advancing gestation, umbilical arterial Doppler waveforms demonstrate a progressive rise in the end-diastolic velocity and a decrease in the impedance indices. When the high-pass filter is either turned off or set at the lowest value, end-diastolic frequencies may be detected from as early as 10 weeks and in normal pregnancies they are always present from 15 weeks.
17 FACTORS AFFECTING UMBILICAL ARTERY DOPPLER FLOW VELOCITY WAVEFORMS Gestational ageEDFV ratio increases with advancing gestational ageFetal heart rateEDFV decreases with decreasing fetal heart rateFetal breathing movementsIncreases variability in the measurementsSite of measurementEDFV is higher near the placental insertion than near the umbilical cord insertion into the fetal abdomenEquipment used : continuous Doppler versus pulsed DopplerContinuous Doppler is more a “blind technique” comparedwith pulsed Duplex Doppler, allowing 2D real time ultrasoundUser experienceReliability increases with increasing experienceRadius of the umbilical arteryDecreasing radius (vasoconstriction) increases EDFVImpedance to pulsatile flow propagationIncreasing vascular impedance increases EDFVDownstream vascular resistance within the microcirculationIncreasing vascular resistance decreases EDFVAngle of the fetal Doppler insonationBest if less than 45˚; <15˚ for MCA absolute peak systolic flowvelocity
18 Diagnostic efficacy of umbilical arterial Doppler in IUGR Author DI Prevalence Sensitivity Specificity PPVFleischer S/D>Aruidini PI>1SDBerkowitz S/D>Divon S/D>Gaziano S/D>Ott S/D>Maulik S/D>Lowery S/D>Lee S/D>While umbilical artery Doppler velocimetry studies are not recommended as an independent antepartum testing modality, it can be extremely useful in differentiating the growth restricted fetus from a constitutionally small fetus. Studies suggest that additional antenatal surveillance is unnecessary in fetuses with suspected growth restriction when the umbilical artery Doppler study is normal.
19 Middle cerebral artery Doppler waveforms Normal flow of the Middle Cerebral Artery in 1º trimesterNormal flow of the Middle Cerebral Artery in 2º and 3º trimester
20 Middle cerebral artery Doppler waveforms (A) Normal middle cerebral artery (MCA) at term - normal peak systolic velocity (58 cm/s), high resistance, low end-diastolic velocity.(B) ‘Brain sparing’ MCA - lower peak, much higher diastolic velocity suggests cerebrovasodilation.(C) Anemic fetus with retained high resistance, elevated peak systolic velocity (77 cm/s).
22 The upper panel represents the venous waveform, correlated with the EKG in the lower panel. A = atrial systole, S = ventricular systole, D = early ventricular diastole. The colored portions of the waveform represent the Tamx for atrial systole (gold), ventricular systole (red), and early ventricular diastole (blue). The yellow arrows represent the measurement of the peak velocity for ventricular systole and early ventricular diastole. The black arrow represents the peak velocity for atrial systole.
23 (A) Ductus venosus (DV) Doppler waveforms at 12 weeks gestation. (B) At 12 weeks gestation, an abnormal a-wave (a), correctly predicted anomalous pulmonary and systemic venous return, proven by fetal echocardiography at 24 weeks.(C) DV at 26 weeks, with 4-phase waveform. (1) atrial contraction (2) ventricular systole, (3) return (ascent) of the annulus (called the y-descent of the DV waveform), & (4) diastole.(D) Normal waveform from the middle hepatic vein which, is only a few millimeters from the DV.
28 Fetal Systemic Vascular Responses in IUGRA/REDV, absent or reversed end-diastolic velocities HARMAN: Clin Obstet Gynecol, 46(4).December
29 Aortic isthmus blood velocity waveform a) normal blood flow pattern in an uncomplicated pregnancy b) antegrade net blood flow (antegrade/retrograde ratio of 2.0)c) retrograde net blood flow with a corresponding value of 0.54 in pregnancies complicated by placental insufficiency.In the sagittal view of the fetus, the aortic arch and the location of the aortic isthmus (white triangle) are shown.
30 Coronary artery blood velocity waveform of a growth-restricted 32 week fetus (heart sparing effect).
31 Alfred Abuhamad et al. Contemporary Ob/Gyn May 1, 2003;48:56-73
32 Evaluation of fetal intrapartum hypoxia by middle cerebral & umbilical artery Doppler velocimetry with simultaneous cardiotocography & pulse oximetrySiristatidis C, Salamalekis E, Kassanos D, Loghis C, Creatsas G Arch Gynecol Obstet Nov 5During active labor the fetus maintains oxygen supply to the brain by redistributing blood flow. In cases of hypoxia this is feasible for only 2 min.
33 Spectral Doppler waveform of an A-A anastomosis with characteristic bidirectional, pulsatile flow.
35 Which Doppler Tests Should be Performed? Uterine arteries depict maternal vascular effects of the invading placentaUmbilical artery Doppler reflects downstream placental vascular resistanceMiddle cerebral artery changes begin when the redistribution of cardiac output reflects rising placental resistanceprecordial veins illustrate fetal cardiac function
37 DIFFERENTIAL DIAGNOSIS OF OLIGOHYDRAMNIOS PPROM--- normal renal vessels, normal umbilical flow & normalfilling of the bladder.Bilateral renal agenesis or dysplasia--- umbilical artery Doppler is normal, but no renal vessels &no bladder fillingSevere hypoxia with IUGR--- fetal measurements are small for gestation, fetal heartlooks dilated & the bowel is echogenic. Dopplerdemonstrates the presence of two renal arteries and absentor reversed end-diastolic frequencies in the umbilical arteries
38 Deficient placentation defined by notched uterine arteries Increased umbilical artery resistance with progression to AEDV/REDVDeclining CPR, brain-sparing MCAAs the arteriovenous ratio decline, ductus venosus abnormality beginsAbnormal biophysical variables emergeOligohydramnios and abnormal (non-reactive) fetal heart rate tracingLoss of fetal breathing movements, body movements and fetal tone
39 1. Umbilical artery Doppler should be available for assessment of the fetal-placental circulation in pregnant women with suspected severe placental insufficiency. (I-A)2. Depending on other clinical factors, reduced, absent, or reversed umbilical artery end-diastolic flow is an indication for enhanced fetal surveillance or delivery. If delivery is delayed to enhance fetal lung maturity with maternal administration of glucocorticoid, intensive fetal surveillance until delivery is suggested for those fetuses with reversed end-diastolic flow. (II-1B)3. Umbilical artery Doppler should not be used as a screening tool in healthy pregnancies, as it has not been shown to be of value in this group. (I-A)4. Umbilical venous double pulsations, in the presence of abnormal umbilical artery Doppler waveforms, necessitate a detailed assessment of fetal health status. (II-3B)5. Measurement of the fetal middle cerebral artery Doppler peak systolic flow velocity is a predictor of moderate or severe fetal anemia and can be used to avoid unnecessary invasive procedures in pregnancies complicated with red blood cell isoimmunization. (II-1A)6. Since inaccurate information concerning fetal Doppler studies could lead to inappropriate clinical decisions, it is imperative that measurements be undertaken and interpreted by expert operators who are knowledgeable about the significance of Doppler changes and who practise appropriate techniques. (II-1A)THE USE OF FETAL DOPPLER IN OBSTETRICS Society of Obstetricians and Gynaecologists of Canada. No. 130, July 2003
40 ConclusionNo single diagnostic modality can provide information complete enough to adequately address the complex nature of IUGR and its interacting fetal compensations and compromisesManagement decisions based on Doppler data are gestational age dependent
41 Thank You For Your Attention! The relative simplicity of the nipple stimulation test may make the CST more desirable to patients and physicians and could be used as a first line screening test instead of the more commonly used NST and BPP.Of all the antepartum testing modalities described in this chapter, none can be described as the best one to use. Each test has certain pros and cons that need to be carefully evaluated in the clinical context in which it is used.