Congenital Adrenal Hyperplasia - NCUSncus.org/files/spring2014/doppler.pdf · 2018-02-09 · •Deliver too late Perinatal asphyxia, IUFD •Can Doppler studies help identify fetuses

3/28/2014

1

Doppler studies in the management

of Fetal growth restriction

Paul Whitecar, MD

Maternal Fetal Medicine

Wake Forest School of Medicine

Outline

• Fetal Growth Restriction and definitions

• Role of Doppler studies in FGR

oUterine Artery

oArterial – Umbilical artery, Middle Cerebral Artery

oVenous – Ductus venosus

• Doppler progression with worsening fetal status

• General recommendations for management


What is in a name?

• Intrauterine growth retardation (IUGR)

• Intrauterine growth restriction (IUGR)

• Fetal growth restriction (FGR)

• Small for gestational age (SGA)


Definition: Fetal Growth Restriction

• An ultrasound estimated fetal weight or

abdominal circumference suboptimal for

gestational age

• FGR = Fetal diagnosis (not neonatal)

• Defining threshold:

• < 10th centile for gestational age

• <5th centile for gestational age (worse

outcome)


Definition: Small for gestational age

(SGA) • Birth weight suboptimal for gestational age

• SGA = NEONATAL diagnosis (not fetal)

• Defining threshold: <10th centile for gestational

age


3/28/2014

2


FGR

• Second leading cause of morbidity and

mortality

• Present in 26% of stillbirths

• Morbidity

• Hypoglycemia

• Hypocalcemia

• Hypothermia

• Necrotizing enterocolitis

• Pulmonary Hypertension


Fetal Growth Restriction

• Long term sequelae

• Ischemic Heart Disease

• Stroke

• Hypertension

• Type II diabetes Barker D. Br J Obstet Gynecol 1992; 99:275

FGR

Normal Pathologic

Extrinsic Intrinsic

(<10th % tile)

80%

20%

75% placental 25%

- Chromosomal

- Infectious

- Anomalies


FGR – 16 week rule

• 1st 16 weeks: all cell division uniform

• 2nd 16 weeks: (16-32 weeks)- combination of

cell division and growth; much more variability

• 32-40 weeks: primary cell growth


FGR – cell growth


Symmetric/ Asymmetric

• Symmetric – all organs decreased

proportionally (hyperplasia/ division)

impairment

• Asymmetric – relatively greater decrease in

abdominal size (liver) than head circumference.

Redistribution of blood flow to the head

3/28/2014

3


Symmetric – 3 causes

• Constitutionally small (i.e. normal)

• Aneuploidy / congenital anomalies

• Early infection


Asymmetric

• Always a substrate problem (nutrition /

placental)


Optimal Management

• Despite over 10,000 publications on the topic,

confusion remains

• Not homogeneous group – what is normal and

abnormal?

• How should they be tested?

• When should delivery occur?


“ I AM A FETUS IN THE WOMB

I FEAR IT MAY BECOME MY TOMB

IF ONLY I COULD GIVE A SHOUT

TO MAKE MY DOCTOR TAKE ME OUT”


Fetal growth restriction- dilemma

• Deliver too early Iatrogenic prematurity

• Deliver too late Perinatal asphyxia, IUFD

• Can Doppler studies help identify fetuses at risk

for intrauterine neurologic injury or death so

that it can be prevented?

• If so, what trigger for delivery should be used?


Fetal Doppler studies- technique

3/28/2014

4


ISUOG guidelines / technique

• Recordings obtained during absence of fetal, body

movements, and if necessary during temporary

maternal breath hold

• Vessel wall filter – “low velocity reject” set as low as

possible to eliminate low frequency noise

• Doppler horizontal sweep fast enough to separate

successive waveforms (ideally 4-6 but no more than 8-

10 cardiac cycles)

• PRF adjusted according to vessel studied – waveform

should fit 75% of Doppler screen


Technique – sweep speed


Technique- vessel wall filter

Higher filter – spurious

effect on EDV Appropriate vessel wall

filter


Which indices to use?

- S/D ratio, RI and PI all

used to describe arterial

flow waveforms

- PI shows linear

relationship with vascular

resistance

- PI does not approach

infinity when absent or

reversed diastolic values


Uterine Artery Doppler studies


Uterine Artery Doppler

• Spiral arteries –

connect maternal

circulation to

endometrium

• Normal pregnancy –

spiral arteries

transformed into low

resistance large

vascular channels

3/28/2014

5



• Preeclampsia / Fetal growth restriction – failure

of trophoblastic invasion results in persistence

of high resistance vasculature

• Theoretically – should be able to detect

increased vascular resistance in uterine artery

Doppler studies


Uterine Artery Doppler- technique

• TA or TV

• Color flow mapping used to identify uterine

artery as it crosses the external iliac artery

• Sample volume 1 cm downstream from

crossover point

• Repeat on contralateral side





Non pregnant 2nd Trimester



Uterine Artery High

Resistance Uterine Artery Notching

3/28/2014

6



• No current standards for gestational age of

testing

• What is abnormal?

• RI (>0.58) or PI (>1.6) or > 95th%tile for

gestational age +/- notching

• Notching: drop of 50 cm/sec from max

diastolic velocity



• Abnormal values in1st and 2nd trimester have

been associated with subsequent adverse

pregnancy outcomes

• Predictive value poor in low risk patients

• Limited interventions

• Benefit in High risk patients? Abnormal or

normal testing alter surveillance


Umbilical Artery Doppler


Umbilical Artery (technique)

• Fetal end, free loop or placental end?

• Impedance highest at fetal end

• ISUOG – “for sake of simplicity and

consistency use free loop”

• Multiples/ comparing longitudinally – fixed end

(placental vs. fetal end) may be more reliable

• 2- vessel cord?

• Single umbilical artery is larger and therefore

impedance is lower


Umbilical artery (Placental resistance)

Low

resistance

(Normal)

High

Resistance

Very High

Resistance


MCA Doppler

3/28/2014

7


MCA Doppler (technique)

• Identify circle with color flow mapping

• Pulse-wave Doppler gate at proximal 1/3 of

MCA

• Angle between ultrasound and blood flow as

close to 00 as possible (not as critical when

measuring PI)

• PSV – use manual calipers; PI auto trace is

acceptable


MCA Doppler and FGR

• Fetal hypoxemia – redistribution of blood flow

to brain, heart and adrenal glands

• “ brain sparing reflex” – increased end diastolic

flow

• As metabolic deterioration occurs, loss of

protective reflex- may normalize


MCA Doppler

• Brain sparing:

• Increased end-diastolic flow velocity (low PI)

• May normalize prior to delivery or fetal demise

• Cerebroplacental ratio

• MCA PI / Umbilical artery PI

• < 5th %tile for gestational age = brain

sparing


MCA Doppler studies


MCA – “Brain sparing”


MCA Doppler

• Peak Systolic Velocity

• May be a better predictor of perinatal mortality

• Progressively increases with advancing

gestation

• Above upper limits of normal- decreased

before demise or reassuring fetal testing

Mari G, et al. Ultrasound Obstet Gynecol

2007; 29:310

3/28/2014

8


Ductus Venosus


Ductus Venosus


Ductus Venosus

• Physiologic status of the

right ventricle

• Biphasic

• 1st peak = ventricular

systole

• 2nd peak = passive

ventricular filling during

diastole

• 3rd peak = atrial

contraction

S D A


Ductus Venosus waveform

• Decreased, absent, or reversed

flow in the A wave (atrial

contraction

• Continuous forward flow =

normal

• Decreased, absent or reversed

flow in A wave – myocardial

impairment due to increased

right ventricular afterload


Ductus Venosus

• Bashat et al

• 604 growth restricted fetuses from 24-32 weeks with

elevated UA PI

• Followed with multi-vessel Doppler assessment

• Predictors for neonatal morbidity and mortality

• Gestational age most significant predictor until 26 6/7

weeks gestation followed by EFW < 600g

• After 27 weeks gestation, abnl DV best predictor for

neonatal complications

Baschat et al, Obstet Gynecol 207;109:253.

3/28/2014

9


Neonatal survival vs. Ductus Venosus

Forward

flow

Absent or

reversed flow

Baschat et al Obset Gynecol 2007;109:253


Should abnormal DV trigger delivery?

• Does it proceed fetal deterioration?

• Yes

• Does it lead time vs. BPP testing?

• By 3 days

• Does this improve perinatal outcome?

• No data from RCTs available.

• Is DV Doppler readily accessible?

• No


TRUFFLE study

• Trial of Randomized Umbilical and Fetal Flow in

Europe

• Study of CTG vs. DV as delivery trigger

• Primary outcome – infant development at age 2

• Enrollment complete

• 542 singleton pregnancies 26-32 weeks

• AC < 10th %tile and UA PI > 95th %tile


TRUFFLE Study

• Preliminary data

• Fetal outcome better than expected

• Perinatal death uncommon (8%)

• 70% survived without morbidity

• Interval to delivery, death and severe morbidity

related to presence of severe maternal hypertension

• Long-term follow up not complete- not unblinded

Lees C, et al. Ultrasound Obstet Gynecol 2013;

42:400.


Doppler Progression


Doppler progression - does it exist?

3/28/2014

10


Progression of Doppler abnormalities

Placental

insufficiency

Sequence of Doppler Abnormalities

Mild

n = 34

↑UA (33 days) ↓CPR

Progressive

n = 49

↑UA (19 days) ↓ CPR (14 days) Brain sparing (4 days) UA

AREDV (14 days) ↑DV (8 days) DV RAV / UV pulsations

Severe early-

onset

n = 21

↑UA (7 days)↓ CPR (9 days) UA AREDV (7 days) Brain sparing

(11 days) ↑DV (5 days) DV RAV/ UV pulsations

Turan, et al. Ultrasound Obstet Gynecol 2008;

32:160.


Progression of Doppler Abnormalities

• PORTO study data

• 1116 non-anomalous fetuses with EFW < 10th %tile

• Followed with multivessel Doppler assessment

• 511 (46%) abnl UA, 300 (27%) abnl MCA and 129

(11%) with abnl DV

• “classic” pattern (abnl UA→MCA→DV) existed but

no more frequently than any other pattern

• Calls into question usefulness of multivessel

assessment for surveillance and timing of delivery in

fetal growth restriction

Unterscheider J, et al. Am J Obstet Gynecol

2013;209:539e1


Progression of Doppler abnormalities


Putting it all together



• “At this time, the evidence does not support

routine screening with uterine artery Doppler in

any particular group of patients. “

• Should be individualized and plan of

management should be put in place based on

results of testing.

Sciscione, Hayes. AJOG 2009


Screening for FGR Minor Risk Factors Major Risk Factors

Maternal Age > 35 Maternal Age > 40 years Nulliparity Smoker > 11 cigarettes per day BMI <20 Cocaine

BMI 25-29.9 Daily vigorous exercise Smoker 1-10 per day Previous SGA Baby

Low fruit intake pre-pregnancy Previous stillbirth Previous preeclampsia Maternal SGA

Pregnancy interval < 6 months Chronic hypertension Paternal SGA Diabetes and vascular disease

Abnormal Down syndrome markers Renal impairment

Antiphospholipid syndrome

Heavy vaginal bleeding/ threatened miscarriage

Echogenic bowel

Severe pregnancy induced hypertension

Unexplained antepartum hemorrhage

Low maternal weight

PAPP-A < 0.4 MoM

Women unsuitable for SFH measurement (i.e. fibroids)

RCOBGYN – Green-top guideline No. 31 (2013)

3/28/2014

11


Screening for FGR

Uterine

Artery

Doppler at

20-24 weeks

3 or more

minor risk

factors

Normal

Abnormal

Assessment

of fetal size

and UA

Doppler in

3rd trimester

One or more

major risk

factors

Serial

assessment of

fetal size and

UA Doppler

from 26-28

weeks RCOBGYN – Green-top guideline

No. 31 (2013) Wake Forest School of Medicine

Umbilical Artery Doppler

• Primary surveillance tool in FGR

• In high-risk group, shown to decrease perinatal

morbidity and mortality

• Reduction in PN deaths 1.7% to 1.2% (RR 0.71),

fewer inductions and cesarean deliveries

• Out performs CTG and BPP in prediction of

poor perinatal outcomes

Alfirevic Z. Cochrane Database Syst Rev

2010.


MCA Doppler studies

• Brain-sparing effect = early sign of fetal hypoxemia

• No systemic reviews as a surveillance tool

• Review of 31 observational studies – MCA Doppler has

limited predictive accuracy for adverse Perinatal

outcomes and PNM

• In preterm FRG – low predictive value specifically with

abnormal UA Doppler

• May be of some benefit in FRG > 32 weeks with normal

UA Doppler

RCOBGYN – Green-top guideline No. 31 (2013)


Ductus venosus

• Retrograde A-wave or pulsatile flow in Umbilical

vein – onset of overt fetal cardiac compromise

• Moderate predictive accuracy in prediction of

perinatal mortality

• Best predictor of acidemia


General recommendations

• Remote from term (<34 weeks)

• Follow Doppler studies – prolong pregnancy if

UA flow is normal. Deliver if absent/reversed

• Ductus venosus as trigger in very preterm (<

27 weeks)


General Recommendations

• Term or late preterm > 34 weeks

• Deliver if Maternal HTN

• Growth arrest x 3-4 weeks

• BPP < 6/10

• Absent or reversed flow (UA Doppler)

3/28/2014

12


Unanswered questions

• Interventions – aspirin in high risk patients (abnl

uterine artery Doppler)

• Customized EFW charts in clinical practice

• Oxygen therapy in severe early onset fetal

growth restriction

• Optimal frequency of surveillance in FGR with

normal and abnormal UA Doppler with diastolic

flow

• Benefit for Uterine artery? Ductus venosus?

Documents

Congenital Adrenal Hyperplasia - NCUSncus.org/files/spring2014/doppler.pdf · 2018-02-09 · •Deliver too late Perinatal asphyxia, IUFD •Can Doppler studies help identify fetuses