Transcript Document

How I do’ : CMR of patients after atrial redirection surgery
for transposition of the great arteries
Sonya V Babu – Narayan MB BS BSc MRCP
c/o Department of CMR, Royal Brompton Hospital, London
National Heart and Lung Institute, Imperial College London
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Adaptation of presentation given at SCMR 2008
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Outline
• Atrial Switch/ Redirection surgery
– Senning operation described 1959
– Mustard operation described 1964
• Long term problems after atrial switch for
TGA and consequent goals of CMR
assessment
• Practical suggestions as to how to achieve
these goals
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Surgery for transposition of the great arteries
Atrial redirection surgery was performed prior to the availability of expertise to perform surgical
arterial switch but may still be performed in selected cases or in patients deemed suitable for double
switch for double discordance (ie atrial and arterial switch surgery).
Illustrations from Brickner ME, Hillis LD, Lange RA. Congenital heart disease in adults.
Second of two parts.N Engl J Med. 2000 Feb 3;342(5):334-42.
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Long term problems after atrial redirection surgery – Mustard or Senning
operation
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Bradyarrhythmia
Tachyarrhythmia
Baffle obstruction
Baffle leak
Ventricular dysfunction
Sudden cardiac death
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Initial Acquisition
Multislice stack in transverse, sagittal and coronal
– We do: transverse half Fourier TSE, and retrospectively gated SSFP for coronal +
sagittal
• transverse half Fourier TSE; easier to measure dimensions of structures such as aortic root
and SSFP multislice gives advantage of jet recognition early on (jet flow is visible because
signal is diminished where there is fluid shear due to dephasing caused by the presence of a
range of velocities in a single voxel)
Advantages of comprehensive multislice imaging include:
– subsequent piloting of cines
– ability to answer specific additional questions retrospectively
• such as presence of LSVC otherwise missed?
• location of coronary sinus prior to intervention?
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CMR post atrial redirection surgery – assessing baffled atrial pathways
3D angiography can be used to assess all the atrial pathways with good results and may be
easier when operator experience is limited
Babu-Narayan, Johansson et al, JCMR supplement 2005
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Status post atrial redirection surgery – cine stack and CE-MRA
-coronal cine stack may help with assessing the baffled atrial pathways
- may also aid review by a second observer
- however the ideal is that these challenging patients should only be
imaged in centres with specific expertise and specific clinical expertise
in their management
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Atrial redirection surgery (Mustard / Senning) Operation
CMR planes acquired to image atrial pathways
Modified from:
Brickner ME, Hillis LD, Lange
RA. Congenital heart disease in
adults. Second of two parts.N
Engl J Med. 2000 Feb
3;342(5):334-42.
White arrow points to baffle
Black asterisk is in the
pulmonary venous
compartment
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CMR to image
parallel
outflow tracts
Note the aorta is the
more anterior vessel
and the parallel nature
of the outflow tracts
How to image the caval atrial pathways after atrial redirection surgery
superior vena caval and inferior vena caval pathways
-Goal to align the plane of imaging to
-the inflow axes of the atria
sagittal multislice
You may now wish to append your first view and revise the
plane relocating on these caval cross cuts to improve
alignment further
Caval pathway views in two planes provide data for alignment
of velocity acquisitions
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How to image the caval atrial pathways after atrial redirection surgery
Cine image of superior vena caval and inferior
vena caval pathways
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How to image the pulmonary venous atrial pathways after atrial redirection
surgery
Cine of pulmonary
venous atrial
compartment
This can be
located
from
sagittal and
coronal
multislice
as shown
with the
yellow bars
sagittal multislice
(look for a
“dumbell” shape on
the sagittal and try
and go through the
apices on the
coronal)
coronal multislice
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CMR of the native outflow tracts– Ao and PA – in transposition of the great
arteries
Cine of parallel
outflow tracts in
transposition of the
great arteries
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CMR status post atrial redirection surgery - ? baffle pathway obstruction
• Case 1: Systemic Venous Atrial Compartment
• Severe SVC obstruction + mild IVC obst
Superior limb obstruction > inferior limb obstruction
Look for dilatation and reversal of flow in azygos
Though Vmax >1m/s may suggest baffle pathway obstruction, this is not interpretable
in isolation of the anatomy or remaining cardiac physiology
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CMR status post atrial redirection surgery - ? baffle pathway obstruction
•Case 2: Systemic Venous Atrial Compartment
•SVC obstruction + mild IVC obst
• A Vmax >1m/sec often suggests obstruction but avoid the pitfall of
assuming this is the case
IVC
IVC
Azy
IVC
Azy
-In this example a peak velocity in the IVC limb > 1m/s (velocity map above)
reflects higher volume of flow through this pathway as the other (SVC) limb
is severely obstructed. It does not reflect severe IVC obstruction.
Anatomically the IVC is only mildly narrowed (above).
-Note the dilated on CEMRA (pictured left) and the reversed flow in the
azygos (white arrow) on the velocity map (pictured top left).
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CMR status post atrial redirection surgery – effect of intervention
•Systemic Venous Atrial Compartment
s/p SVC atrial pathway
transcatheter stenting
s/p IVC atrial pathway
transcatheter stenting
(The stent appears dark )
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CMR status post atrial redirection surgery – effect of intervention
SVC atrial pathway obstruction
s/p SVC atrial pathway transcatheter stenting
azygos (red arrow) no longer appears dilated)
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CMR status post atrial redirection surgery - PVAC obstruction
•Pulmonary Venous Atrial Compartment
“hourglass” narrowing (black asterisk)
Obstructed pulmonary venous atrial compartment (asterisk)
Continuous flow on in-plane velocity mapping
No “hourglass”
narrowing,
unobstructed
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•ideally the peak velocity anywhere in the baffle
pathways should not be > 1m/s
•aliasing occurred at 1 m/sec and Vmax is 1.7m/s
•continuous flow is seen in this significant
stenosis (white arrow points at continuous jet)
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CMR status post atrial redirection surgery - additional long axis views
RV
LV
Ao PA
RV
PVAC
LV
Ao
RA
PA
RV
LA
LV
these views are typical in 20-40 year old adults after atrial redirection surgery
adds to qualitative impression of ventricular size and function,
views comparative with transthoracic and transoesphageal
echocardiography and cardiac catheterisation (therefore familiar)
therefore aids communication with clinicians
demonstrates connections (educational)
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Identifying residual VSD / patch leak
• Patch leak may be seen in:
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LVOT view
RV in and out
RV oblique views
SA view as opposite
• If uncertain:
– cross-cut a SA view where a jet core is
suspected
• Add Non-Breath-Hold velocity mapping:
– Aorta and PA (at sinotubular junction Ao and in main PA)
– Calculate Qp:Qs ratio
– Stroke volume ratio may be relevant
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CMR status post atrial redirection surgery – look for residual VSD
Use Ao PA velocity mapping to estimate shunt
These cines demonstrate a residual VSD in the same
patient (white arrow)
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CMR status post atrial redirection surgery – look for subpulmonary
stenosis
Ao
PA
RV
LV
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CMR status post atrial redirection surgery – assess presence and degree
of TR and AR
•TR, AR and the Systemic RV
Ao
RV
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CMR status post atrial redirection surgery – assess presence and degree
of ventricular dysfunction
•Systemic RV and Sub-Pulmonary LV Dysfunction
RV
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RV measurement in ACHD
• RV trabeculations:
– coarse, thickened and significant in summed volume
• we do planimeter trabeculations, including them in the RV mass and excluding
them from the blood pool
• we count the septum as part of the systemic ventricle
• our reproducibility is reported
– planimetry challenging
• use stroke volume as check
– velocity mapping of Ao and Pa (these can usefully be obtained in a single
acquisition as the outflow tracts are parallel)
• a useful cross-check on manual contour data
• for our centre’s method, interobserver and intraobserver variablity in this
group of patients see
Babu-Narayan SV, Goktekin O, Moon JC, Broberg CS, Pantely GA, Pennell DJ, Gatzoulis MA, Kilner PJ. Late
gadolinium enhancement cardiovascular magnetic resonance of the systemic right ventricle in adults with previous atrial
redirection surgery for transposition of the great arteries. Circulation. 2005 ;111:2091-2098
• Establish your own, reproducible protocol for
the RV
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CMR status post atrial redirection surgery - other
PA
PA
Ao
PA
PA
RV
•Here the SVC limb is compressed by 7 cm diameter PA aneurysmal dilatation
•Also note previously repaired fenestrated VSD (far left cine)
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Summary of potential imaging choices for TGA post atrial redirection
surgery
• Multislice
– Sagittal
– Coronal
– Tranaxial
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Systemic venous compartment coronal cine
Pulmonary venous compartment cine (PVAC)
Outflow tracts cine
Short axis stack cines
Thrupl flow AO and PA (single acqusition)
• Consider coronal ± tranaxial cine stack for
review elsewhere
• Cross cut SVC and IVC cines
• Throughplane ± inplane flow SVC / IVC / PVAC
• Throughplane ± inplane flow of azygos
• Characterise any PS/VSD
• Additional long axis ventricular views
• 3D Truefisp and or 3D CE-MRA
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All patients
Consider
Goals of CMR status post atrial redirection surgery – Take Home
1. presence, degree and functional
significance of atrial pathway narrowing
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Consider
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anatomical size each limb
Velocity generally < 1m/sec
time course of flow ie continuous flow =
obstruction
azygos dilatation
flow direction in azygos
2. ventricular function, (particularly
systemic)
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Consider
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Presence of shunt
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Residual VSD
Baffle leak
3. a condition possibly best imaged in, or at
least with support from, experienced
centres
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If in doubt REFER
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Acknowledgements
Philip J Kilner, Michael A Gatzoulis and Dudley J Pennell
James Moon
Craig S Broberg
George Pantely
Bengt Johansson
Siew Yen Ho
Christopher Lincoln
Wei Li
Tim Cannell
Steve Collins
Gill Smith
Karen Symmonds
Ricardo Wage
•Illustration shows late gadolinium
enhancement (arrows) in the systemic RV
seen late after atrial redirection surgery
•This may prove to have a risk stratification
role*
See Refs:
Babu-Narayan et al, Circulation 2005
Giardini et al, Am J Cardiol 2006
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Patients
attending the
Royal Brompton
Hospital Adult
Congenital Heart
Disease Unit
Staff of the Adult
Congenital Heart
Disease, CMR,
Non Invasive
Cardiology,Paediatric
Cardiology, Paediatric
Cardiac Surgery and
Pathology Units