sonya v babu – narayan mb bs bsc mrcp c/o department of cmr, royal brompton hospital, london
DESCRIPTION
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 [email protected]. - PowerPoint PPT PresentationTRANSCRIPT
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, LondonNational Heart and Lung Institute, Imperial College London
Adaptation of presentation given at SCMR 2008
Outline
• Atrial Switch/ Redirection surgeryAtrial Switch/ Redirection surgery– Senning operation described 1959Senning operation described 1959– Mustard operation described 1964Mustard operation described 1964
• Long term problems after atrial switch for Long term problems after atrial switch for TGA and consequent goals of CMR TGA and consequent goals of CMR assessmentassessment
• Practical suggestions as to how to Practical suggestions as to how to achieve these goalsachieve these goals
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.
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).
Long term problems after atrial redirection surgery – Mustard or Senning operation
• BradyarrhythmiaBradyarrhythmia
• TachyarrhythmiaTachyarrhythmia
• Baffle obstructionBaffle obstruction
• Baffle leakBaffle leak
• Ventricular dysfunctionVentricular dysfunction
• Sudden cardiac deathSudden cardiac death
Initial Acquisition
Multislice stack in transverse, sagittal and coronal Multislice stack in transverse, sagittal and coronal – We do: transverse half Fourier TSE, and retrospectively gated SSFP for coronal + We do: transverse half Fourier TSE, and retrospectively gated SSFP for coronal +
sagittal sagittal • transverse half Fourier TSE; easier to measure dimensions of structures such as aortic root 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 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 signal is diminished where there is fluid shear due to dephasing caused by the presence of a range of velocities in a single voxel)a range of velocities in a single voxel)
Advantages of comprehensive multislice imaging include:Advantages of comprehensive multislice imaging include:– subsequent piloting of cines subsequent piloting of cines – ability to answer specific additional questions retrospectivelyability to answer specific additional questions retrospectively
• such as presence of LSVC otherwise missed?such as presence of LSVC otherwise missed?• location of coronary sinus prior to intervention?location of coronary sinus prior to intervention?
[email protected], Johansson et al, JCMR supplement 2005
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
-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
Status post atrial redirection surgery – cine stack and CE-MRA
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.
Atrial redirection surgery (Mustard / Senning) Operation
CMR planes acquired to image atrial pathways
CMR to image parallel
outflow tracts
White arrow points to baffleBlack asterisk is in the pulmonary venous compartment
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
You may now wish to append your first view and revise the plane relocating on these caval cross cuts to improve alignment furtherCaval pathway views in two planes provide data for alignment of velocity acquisitions
superior vena caval and inferior vena caval pathways-Goal to align the plane of imaging to -the inflow axes of the atria
sagittal multislice
How to image the caval atrial pathways after atrial redirection surgery
Cine image of superior vena caval and inferior vena caval pathways
How to image the pulmonary venous atrial pathways after atrial redirection surgery
Cine of pulmonary venous atrial compartment
This can be located
fromsagittal and
coronal multislice as shownwith the
yellow bars(look for a
“dumbell” shape on the sagittal and try and go through the
apices on the coronal)
sagittal multislice
coronal multislice
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
• Case 1: Systemic Venous Atrial Compartment• Severe SVC obstruction + mild IVC obst
CMR status post atrial redirection surgery - ? baffle pathway obstruction
Superior limb obstruction > inferior limb obstructionLook for dilatation and reversal of flow in azygosThough Vmax >1m/s may suggest baffle pathway obstruction, this is not interpretable in isolation of the anatomy or remaining cardiac physiology
•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
CMR status post atrial redirection surgery - ? baffle pathway obstruction
-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).
IVCIVC
Azy
Azy
IVC
•Systemic Venous Atrial Compartment
CMR status post atrial redirection surgery – effect of intervention
s/p SVC atrial pathway transcatheter stenting
s/p IVC atrial pathway transcatheter stenting
(The stent appears dark )
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)
•Pulmonary Venous Atrial Compartment
CMR status post atrial redirection surgery - PVAC obstruction
•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)
No “hourglass” narrowing,
unobstructed
“hourglass” narrowing (black asterisk) Obstructed pulmonary venous atrial compartment (asterisk)
Continuous flow on in-plane velocity mapping
*
CMR status post atrial redirection surgery - additional long axis views
these views are typical in 20-40 year old adults after atrial redirection surgeryadds to qualitative impression of ventricular size and function, views comparative with transthoracic and transoesphagealechocardiography and cardiac catheterisation (therefore familiar)therefore aids communication with cliniciansdemonstrates connections (educational)
LVRV
PAAo
RA LA
Ao
RVLV
LVRV
PVACPA
Identifying residual VSD / patch leak
• Patch leak may be seen in:– 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
CMR status post atrial redirection surgery – look for residual VSD
Use Ao PA velocity mapping to estimate shuntThese cines demonstrate a residual VSD in the same patient (white arrow)
CMR status post atrial redirection surgery – look for subpulmonary stenosis
PAAo
RVLV
•TR, AR and the Systemic RV
CMR status post atrial redirection surgery – assess presence and degree of TR and AR
Ao
RV
•Systemic RV and Sub-Pulmonary LV Dysfunction
CMR status post atrial redirection surgery – assess presence and degree of ventricular dysfunction
RV
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
CMR status post atrial redirection surgery - other
•Here the SVC limb is compressed by 7 cm diameter PA aneurysmal dilatation•Also note previously repaired fenestrated VSD (far left cine)
Ao
RV
PAPA PAPA
Summary of potential imaging choices for TGA post atrial redirection surgery
All patients
• MultisliceMultislice– SagittalSagittal– CoronalCoronal– TranaxialTranaxial
• Systemic venous compartment coronal cine Systemic venous compartment coronal cine • Pulmonary venous compartment cine (PVAC)Pulmonary venous compartment cine (PVAC)• Outflow tracts cineOutflow tracts cine• Short axis stack cinesShort axis stack cines• Thrupl flow AO and PA (single acqusition)Thrupl flow AO and PA (single acqusition)
Consider
• Consider coronal Consider coronal ±± tranaxial cine stack for tranaxial cine stack for review elsewherereview elsewhere
• Cross cut SVC and IVC cinesCross cut SVC and IVC cines• Throughplane Throughplane ± ± inplane flow SVC / IVC / PVACinplane flow SVC / IVC / PVAC• Throughplane Throughplane ± ± inplane flow of azygos inplane flow of azygos • Characterise any PS/VSDCharacterise any PS/VSD• Additional long axis ventricular viewsAdditional long axis ventricular views• 3D Truefisp and or 3D CE-MRA3D Truefisp and or 3D CE-MRA
Goals of CMR status post atrial redirection surgery – Take Home
1.1. presence, degree and functional presence, degree and functional significance of atrial pathway narrowingsignificance of atrial pathway narrowing
• ConsiderConsider• anatomical size each limbanatomical size each limb• Velocity generally < 1m/sec Velocity generally < 1m/sec • time course of flow ie continuous flow = time course of flow ie continuous flow =
obstructionobstruction• azygos dilatationazygos dilatation• flow direction in azygosflow direction in azygos
2.2. ventricular function, (particularly ventricular function, (particularly systemic) systemic)
• ConsiderConsider• Presence of shuntPresence of shunt
• Residual VSDResidual VSD• Baffle leakBaffle leak
3.3. a condition possibly best imaged in, or at a condition possibly best imaged in, or at least with support from, experienced least with support from, experienced centrescentres
• If in doubt REFERIf in doubt REFER
Acknowledgements
James MoonJames MoonCraig S BrobergCraig S BrobergGeorge PantelyGeorge PantelyBengt Johansson Bengt Johansson Siew Yen HoSiew Yen HoChristopher LincolnChristopher LincolnWei LiWei LiTim CannellTim CannellSteve Collins Steve Collins Gill SmithGill SmithKaren SymmondsKaren SymmondsRicardo WageRicardo Wage
PatientsPatients attending the attending the Royal Brompton Royal Brompton Hospital Adult Hospital Adult Congenital Heart Congenital Heart Disease UnitDisease Unit
StaffStaff of the Adult of the Adult Congenital Heart Congenital Heart Disease, CMR, Disease, CMR, Non Invasive Non Invasive Cardiology,Paediatric Cardiology,Paediatric Cardiology, Paediatric Cardiology, Paediatric Cardiac Surgery and Cardiac Surgery and Pathology UnitsPathology Units
Philip J Kilner, Michael A Gatzoulis and Dudley J PennellPhilip J Kilner, Michael A Gatzoulis and Dudley J Pennell
•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 2005Giardini et al, Am J Cardiol 2006