ECHO Workbook - NPEU · ECHO Workbook Outcome after Selective Early Treatment for Closure of Patent...

ECHO Workbook Outcome after Selective Early Treatment for Closure of Patent Ductus ARteriosus in Preterm Babies

The Baby-OSCAR Trial

Prepared by Dr N V Subhedar, Professor S Gupta, Dr A W R Kelsall, Dr J Wyllie on behalf of the Baby-OSCAR Collaborative Group

EudraCT No.: 2013-005336-23

ISRCTN: 84264977

of 14 Baby-OSCAR ECHO Workbook ©, Version 2, 9 Dec 2016

Contents

Background ........................................................................................................................ 2

Who can perform echocardiogram assessments for the Baby OSCAR Trial? ..................... 2

Echo criteria for Baby OSCAR Trial .................................................................................... 2

What assessments need to be performed? ........................................................................ 3

Assessment of ductal patency and flow characteristics (appendix 1) .................................. 3

Assessment of ductal dimension (appendix 2) .................................................................... 3

Assessment of a hyperdynamic circulation (appendix 3)..................................................... 3

Assessment of ductal steal (appendix 4) ............................................................................ 3

Appendix 1 - Assessment of ductal patency and flow characteristics .................................. 4

Appendix 2 - Assessment of ductal dimension .................................................................... 8

Appendix 3 - Assessment of a hyperdynamic circulation .................................................. 10

Appendix 4 - Assessment of ductal steal .......................................................................... 12

Contact details ..................................................................... Error! Bookmark not defined.

© Copyright “The University of Oxford, 2015”.

Permission granted to reproduce for educational use only. Commercial copying, hiring, lending is

prohibited.


Background

There is substantial variation in the way that the size of the ductus arteriosus is measured

and the impact of a ductal shunt assessed. A number of echocardiographic markers are used

but there is no accepted ‘gold standard’ since each is individually poorly correlated with

outcome and there are concerns about poor repeatability.

The purpose of this workbook is to guide neonatal echocardiographers in performing

echocardiographic assessments required for the Baby-OSCAR Trial. It aims to standardise

assessment of the following echocardiographic parameters:

ductal size

ductal flow patterns

measures of a hyperdynamic circulation

measures of ductal steal

Who can perform echocardiogram assessments for the Baby OSCAR Trial?

Neonatologists, cardiologists (consultants/trainees) or delegated echocardiographers who

have expertise in neonatal echocardiography and are able to visualise and assess the ductus

arteriosus using conventional views are able to perform trial echocardiograms. At the first

scan, it is desirable that the echocardiographer screens for normal cardiac anatomy. If any

structural heart disease is suspected clinically or echocardiographically, appropriate action

should follow according to local policy.

Echo criteria for Baby-OSCAR Trial

1. Trial entry: PDA dimension of ≥ 1.5 mm (determined by gain optimised colour Doppler), and Unrestrictive pulsatile left to right flow in PDA (ratio of flow velocity in PDA

Maximum (Vmax) to Minimum (Vmin) > 2:1)) or, growing flow pattern (< 30% right to left).

2. Rescue treatment:

Presence of a large PDA with a ductal dimension of ≥ 2.0 mm AND Unrestrictive pulsatile left to right flow in PDA AND Presence of a hyperdynamic circulation OR ductal steal


What assessments need to be performed?

1. At trial entry, assessing eligibility for inclusion:

Obtain high left parasternal (‘ductal cut’) view

Assess ductal patency and ductal flow characteristics

Measure ductal dimension

2. At subsequent examinations, in addition to (1) the following assessments should be

performed:

Assess presence of a hyperdynamic circulation

Assess presence of ductal steal

Assessment of ductal patency and flow characteristics (Appendix 1)

a) Obtain high left parasternal (‘ductal cut’) view

b) Assess ductal patency and flow direction using pulse wave and colour Doppler

c) Sample ductal flow using pulse wave Doppler interrogating the flow characteristics in

the middle of the ductus

d) Categorise the ductal flow pattern into one of four patterns:

bidirectional, growing, pulsatile, closing

e) Measure and calculate the pulsatility ratio (Vmax:Vmin)

Assessment of ductal dimension (Appendix 2)


b) Optimise colour flow gain settings

c) Measure colour flow ductal dimension at narrowest point (usually at the pulmonary

end of the ductus)

d) Repeat (c) and calculate the mean of at least three measurements

Assessment of a hyperdynamic circulation (Appendix 3)

a) Obtain parasternal long axis view

b) Measure left atrial:aortic root ratio using M-mode

c) Repeat (b) and calculate the mean of at least three measurements

Assessment of ductal steal (Appendix 4)

a) Obtain view of descending aorta using a high left parasternal or arch view

b) Sample post-ductal aortic flow using pulse wave Doppler

c) Record the presence of retrograde post-ductal aortic flow

d) Alternatively, sample the coeliac or superior mesenteric artery to detect the

presence of retrograde flow


Appendix 1 ─ Assessment of ductal patency and flow characteristics


High parasternal view

b) Assess ductal patency and flow direction using conventional and colour Doppler

Use colour Doppler to establish the ductus is patent taking care not to confuse flow

in the left pulmonary artery with right to left ductal flow. Assess the ductal flow

pattern using either pulse wave Doppler sampling in the middle of the ductus, or

continuous wave Doppler, as appropriate.

A degree of bidirectional flow is normal in the first 12 hours after birth but a

right to left component of > 30% of the cardiac cycle should be considered

abnormal and prompt formal evaluation. Identification of a pure right to left shunt,

or bidirectional flow with a predominant right to left component, are situations

where it is imperative to exclude a duct-dependent systemic circulation prior to trial

entry, treatment with the study drug or rescue treatment with a COX inhibitor.


Right to left flow through ductus arteriosus


Once ductal patency has been established, and right to left flow excluded, categorise

the ductal flow pattern into one of the following types:

i) Bidirectional

ii) Growing

iii) Pulsatile

iv) Closing


If the flow pattern is pulsatile, measure and calculate the pulsatility ratio (Vmax:Vmin)

Vmax is the peak left to right velocity, usually in diastole. Vmin is the minimum left to right velocity. A ratio of > 2 is considered to represent a pulsatile flow pattern. In this example, Vmax:Vmin = 3.13/2.03 = 1.54


Appendix 2 ─ Assessment of ductal dimension

a) Obtain high left parasternal (‘ductal cut’) view as before.

b) Optimise colour flow gain settings by (1) adjusting colour gain scale to obtain optimal

colour flow within the course of the ductus and (2) adjusting colour gain to eliminate

any peripheral colour interference by reducing gain until colour flow cannot be seen

outside blood vessels.

c) Measure colour flow ductal dimension at narrowest point (usually at the pulmonary end of

the ductus) by frame-to-frame analysis of the video loop selecting frames with the clearest

discrete appearance of the ductus. Use 2D imaging to guide the point at which colour

dimension should be measured.

d) Repeat (c) and calculate the mean of at least three measurements.

Optimisation of colour gain settings: excessive gain

Optimisation of colour gain settings: insufficient gain


Measurement of colour diameter at pulmonary end of the ductus arteriosus

Pulmonary

end of ductus


Appendix 3 ─ Assessment of a hyperdynamic circulation

a) Obtain parasternal long axis view.

Parasternal long axis view

b) Measure left atrial:aortic root ratio using M-mode, ensuring the cursor is at right

angles to the aorta and the posterior wall of the left atrium.

c) Repeat (b) and calculate the mean of at least three measurements.

M-mode assessment of LA:Ao root ratio


Where to make M-mode measurements of left atrial and aortic root dimensions

d) For the purposes of this trial, a LA:Ao ratio of > 2.0 is considered to represent

significant left atrial dilatation secondary to volume overload of the left heart.


Appendix 4 ─ Assessment of ductal steal

a) Obtain view of descending aorta using a high left parasternal or arch view.

b) Sample post-ductal aortic flow using pulse wave Doppler, using angle-correction if

necessary.

c) Record the presence of retrograde post-ductal aortic flow.

High parasternal view with Doppler sample volume in post-ductal descending aorta

Doppler recording (normal antegrade flow in diastole)


Doppler recording (abnormal retrograde diastolic post-ductal aortic flow)

d) Alternatively, sample the coeliac or superior mesenteric artery to detect and record

the presence of retrograde diastolic flow.

Sampling in the coeliac artery – normal antegrade diastolic flow

Retrograde diastolic flow in superior mesenteric artery


Baby-OSCAR is funded by the National Institute for Health Research HTA Programme (project reference 11/92/15)

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