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Dr. Raju R SahetyaM.D., D.G.O., D.F.P., F.C.P.S., F.I.C.O.G.,

OBSTETRICIAN & GYNAECOLOGISTInfertility & Laparoscopic Surgeon

Pushpaa HospitalLokhandwala Complex, Andheri (w),

Mumbai, Indiawww.pushpaahospital.com, drrajusahetya@gmail.com

Color Doppler in Obstetrics “A true friend of Fetus at Risk”

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HonoraryHinduja Healthcare – Surgical Hospital, Khar, Mumbai

Visiting Hospitals BSES * Mumbadevi * Hiranandani

Vice PresidentIndian Society for Prenatal Diagnosis & Fetal Therapy (ISPAT)

Member Excecutive CouncilMumbai Obstetrics & Gynaecology Society (MOGS)

Association of Fellow Gynaecologist (AFG)Assciation of Medical Consultant (AMC)

Current Position HeldMOGS – PNDT & Academic Cell,

FOGSI – Sexual Medicine CommitteeEditorial Board – ISPAT Int. Journal of Prenatal Diagnosis & AFG Times

RotarianPast President Rotary Club of Bombay Airport

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“I OWE TO MY ALMA MATER !”

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Introduction

In a world in which the study of

“Life in Utero and Antenatal Diagnosis”

of diseases have become realities.

Research on pathophysiology

of antenatal period has taken on

a new importance and relevance

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Doppler Velocimetry

True Friend - Colour Doppler

Based on physical principle of change in frequency of a sound wave when it is reflected by a moving object

Described in 1842

by an Austrian physicist and mathematician

Johann Christian Doppler.

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Color Doppler Imaging Doppler principle is applied to enable vascular flow to be

identified in a color-coded display, which indicates the direction of flow

Blood flowing towards the ultrasound transducer is conventionally depicted in a band of colors ranging from deep red (low velocity) to bright yellow (high velocity)

Flow in direction away from the transducer is indicated by band of colors ranging progressively from deep blue (low velocity) to cyan (high velocity)

Doppler imaging illustrates only the direction of flow, color-coded mean velocities and the range of the mean velocities

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Fetal circulation Three arterial-venous shunts of fundamental importance to the maintenance of fetal oxygen.•Ductus venosus(DV) that carries oxygenated blood from the umbilical vein to IVC & RA

•The foramen ovale that allows the passage of blood from right to the left atrium

•The Ductus arteriosus that carries blood from the pulmonary artery into aorta, thereby effectively by - passing the pulmonary circulation.

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Colour Doppler offers the Obstetrician

A noninvasive

Easily repeatable

Harmless technique

for studying the Fetus and Placental Circulation

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Color Doppler plays a vital role in the diagnosis of fetal

cardiac defects.

assessment of the hemodynamic responses to fetal hypoxia and anemia.

diagnosis of other non-cardiac malformations.

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Fetus at Risk

Site and viability of early pregnancy Intrauterine growth restriction (IUGR) Fetal Anemia Fetal Anomalies Prediction of Pre-eclampsia Screening for Down Syndrome

A long Term Friendship indeed

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Colour DopplerSite and viability of early pregnancy

Increased vascularity surrounding

the gestational sac

Increased flow through spiral arteries

Excellent Visual demonstration of cardiac activity

Viability or non-viability on a single scan

GS at 6-7 weeks

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Colour DopplerIntrauterine growth restriction (IUGR)

Changes in the Arterial Circulation

Changes in the Venous Circulation

Changes in the Fetal Heart

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Pathophysiology of fetal hypoxiaPlacental Insufficiency

Decreased in growth

Decrease in movements

Progressive decompensation

Respiratory and metabolic acidosis

Renal insufficiency

Decreased amniotic fluid volume

Myocardial compromise

Absent or reversed atrial flow in the DV

Late deceleration in the FHR

Fetal death

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Doppler based management in IUGR

Doppler USG provides us valuable information on the utero-placental vascular resistance and, indirectly on blood flow.

Analyses of the Doppler waveforms are made by measuring the peak systolic(S) & end diastolic (D) velocities.

Three indices are considered related to vascular resistance: S/D, RI, PI.

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Doppler indices

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Changes in the Arterial CirculationUterine arteries Doppler

The changes in vascular resistance is more marked in uterine artery closer to placental implantation site.

Diastolic notching is an index of increased impedance to flow.

Abnormal uterine arteries waveforms after 24 wks of gestation are associated with development of

preeclampsia, abruption, FGR, morbidity & mortality.

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Uterine artery

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Changes in the Arterial Circulation Umbilical artery – Signature Vessel

A direct reflection of the flow within the placenta

First vessel to be studied when suspecting IUGR

characteristic saw-tooth appearance of arterial flow in one direction and continuous umbilical venous blood flow in the other.

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The sequence of events of progressive fetal compromise secondary to placental insufficiency:

Increased UA S/D resistance without centralization of flow.

Means UA S/D above normal and MCA S/D normal less worrisome

Indicates need for closer, frequent fetal surveillanceTo determine whether or not there is

further deterioration.

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Absent umbilical artery diastolic flow (AUADF)

•UA blood flows only during systole as a result, the oxygen supply to the fetus is decreased and mild metabolic acidosis.

•Occurs days to weeks prior to abnormalities found on other measures of fetal health - NST, BPP, CST, these indicating urgent delivery.

May not affect long-term neurological outcome

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Reversed umbilical artery diastolic flow (RUADF)

•“Fetus to placenta” an ominous sign, blood flow is reversed during diastole, fetuses need to be delivered promptly.

At risk of neonatal death and significant morbidity.

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Fetal cerebral circulation In mild hypoxia – UA resistance increased, no change

in MCA - adaptation of fetal circulation

In progressive hypoxia – ‘Brain sparing effect’ presence of such compensation suggest a compromised fetus

Doppler waveform depicts – increased diastolic flow with decreased pulsatility index

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Fetal cerebral circulation

Continuing hypoxia – the over stressed fetus loses the brain sparing effect – diastolic flow returns to normal

Reflects a terminal de-composition in the setting of acidemia or brain edema

Reversal of diastolic flow

grave and irreversible fetal neurological outcome

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Middle Cerebral Artery

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Fetal Aorta The advent of Aortic Isthmus in analyzing early

disruption in the cerebral perfusion – New vessel of hope.

Severe hypoxia – diastolic flow reverses, correlates with gross acidemia & necrotizing enterocolitis

Greater the reverse isthimic flow, lower the IFI

higher risk of cerebral damage.

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Changes in the Venous Circulation

Doppler waveforms – central venous system of fetus reflects physiological status of rt. Ventricle

Information on the ventricular preload, myocardial compliance & rt. Ventricular end-diastolic pressure

Vessels that give invaluable information of adaptation to fetal hypoxia are IVC, DV & UV

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Changes in the Venous CirculationDuctus Venosus Doppler

DV a continuation of intra abdominal umbilical vein with a narrow inlet and a wider outlet connects to IVC

Waveform is M pattern, first and second peak coinciding with ventricular systole & diastole

In IUGR-progressive hypoxia and worsening contractility of the ventricles and atria secondary to myocardial ischemia

DV shows decrease in forward flow due to increasing pressure gradient in the rt. Atrium.

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Changes in the Venous CirculationDuctus Venosus Doppler

Tricuspid regurgitation causes reversal of flow in IVC which eventually leads to reversal of flow in the DV

Associated with worsening fetal hypoxia and acidemia, preceding abnormities in the fetal heart rate

Reverse flow velocity waveform at the DV

leads to fetal death.

Abnormal UA & MCA waveform, without reverse flow in DV

fetal death is not likely

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Umbilical vein

In normal pregnancy – monophasic waveform with

continuous forward flow

Gradually decreases 20th to 38th wks of gestation

Last vessels to change its flow pattern in fetal hypoxia

In severe cases – reversal of flow in IVC & DV

Pulsatile flow pattern begins due to high resistance

Increased risk of adverse perinatal outcome

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Changes in the Fetal HeartInvolve preload, after load, ventricular compliance and myocardial contractility

Abnormalities in the right diastolic followed by right systolic indices followed by left diastolic & systolic cardiac indices

Left systolic function last to become abnormal ensures an adequate left ventricular output supply to cerebral and coronary circulation

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Changes in the Fetal HeartChanges in both sides

Preload is reduced at both atrioventricular valves due to hypovolemia & decreased filling

Reduced myocardial contractility

Ventricular ejection force is decreased

Shorter time to delivery, non-reassuring fetal heart tracing and a lower pH ( acidosis) at birth.

Values validitates severity of fetal compromise

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Changing trends in Doppler In 21st century assessment of IUGR Fetuses

Identify pregnancy at risk of IUGR and / or prevent decompensation, hence doppler shifting, from curative to preventive medicine.

12 to 16 wks screening of Uterine artery in high risk can identify accurately a subset of women who are destined for major complications attributed to placental diseases.

New vessels giving new hope – Aortic Isthmus velocity waveform (Isthimic flow index-IFI) becomes abnormal at earlier stage of fetal compromise than DV.

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Colour Doppler in Fetal Anemia

Middle Cerebral Artery peak systolic flow velocity (MCA –PSV) serves as a useful measure of fetal anemia severe enough to require IUT.

Almost 70% of cordocentesis can be avoided.

Hence reduces the potential risks of pregnancy loss

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Middle Cerebral Artery

Flow velocity waveform in the fetal middle cerebral artery in a severely anemic fetus at 22 weeks (left)

Normal fetus (right). In fetal anemia, blood velocity is increased

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Color Doppler in Fetal Anomalies

Fetal cardiac anomalies, anomalies of vascular origin

Greatly enhanced, diagnosed and characterized much better

Changes in the flow pattern are demonstrated

Transposition of the great vessels (TGV)

Total anomalous pulmonary vasculature (TAPV)

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Color Doppler Down Syndrome Screening

Fetuses with Down syndrome exhibit changes in the fetal circulation & echocardiography @ 11 to 14 wks

The normally forward flow in the fetal ductus venosus is absent or reversed during atrial contraction in Down syndrome fetuses

An independent marker.

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Doppler ultrasound for the fetal assessment in high-risk pregnancies (Cochrane Review). In: The Cochrane Library, 1999. Neilson JP and Alfirevic Z

Trudinger et al 1987 McParland et al 1988 Tyrrell et al 1990 Hofmeyr et al 1991 Newham et al 1991 Burke et al 1992

11 Studies Included In Analysis

Almstrom et al 1992Biljan et al 1992Johnstone et al 1993Pattison et al 1994Nienhuis et al 1997

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Doppler ultrasound for the fetal assessment in high-risk pregnancies

Nearly 7000 patients were included

The trials compared no Doppler ultrasound to Doppler ultrasound in high-risk pregnancy (hypertension or presumed impaired fetal growth)

Meta analysis

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Doppler ultrasound for the fetal assessment in high-risk pregnancies

A reduction in perinatal deaths. Fewer inductions of labour . Fewer admissions to hospital . no report of adverse effects . No difference was found for fetal distress

in labour . No difference in caesarean delivery .

Main results

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Conclusion

Placental insufficiency highly associated with perinatal mortality and morbidity.

Uterine artery important role in predicting PIH & IUGR at 20-24 wks.

Reverse flow in the umbilical artery, along with pathologic waveform in the venous system are the best predictor of severe fetal distress.

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Conclusion

Role of Doppler has shifted from curative to preventive one with truly informed and meaningful brain oriented fetal care.

Delivery of the sick fetus can be appropriately timed to prevent associated complications

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Colour Doppler in Obstetrics

“A True Friend of Fetus at Risk”