This document discusses the use of CT scans and 3D printing to characterize the left atrial appendage (LAA) anatomy prior to LAA occlusion procedures. It notes that the complex structure of the LAA makes sizing and implantation of closure devices challenging when relying solely on 2D TEE imaging. The document outlines how pre-procedural CT scans can provide detailed information on LAA dimensions, bends, lobes and surrounding structures to aid in device selection and planning fluoroscopy angles. It also discusses how 3D printing of the LAA can allow for rehearsal of the procedure and sizing agreement with implanted devices in over 95% of cases compared to 45% when using TEE alone.

1. Dr. B. Vaquerizo, MD, PhD
Hospital del Mar, Barcelona
TAC para planificar el procedimiento e
impresión 3D: ¿es realmente útil?
Marzo, 2018

2. • A fixed-shape device cannot be used for LAAO because the complex and
variable structure of the LAA
Background
31.25 kHz was used to reduce noise and improve the
signal-to-noise ratio. The fractional echoes (echo time of
1.08 ms) were used to provide T1-weighting and minimize
flow artifacts, and a flip angle of 20 degrees was chosen to
the entire measurement time had to be
the bolus of the contrast agent. Mo
breathing were eliminated by patient’s
time of the sequence (Ͻ15 s).
Figure 2 CT and MRI Scans of a Chicken Wing LAA Morphology
The Chicken Wing LAA morphology presents an obvious bend in the proximal or middle part of the dominant lobe, or folding back of the LAA an
distance from the perceived LAA ostium. This type of LAA may have secondary lobes or twigs. CT (A) and MRI (B). Abbreviations as in Figure 1
1.08 ms) were used to provide T1-weighting and m
flow artifacts, and a flip angle of 20 degrees was c
Figure 2 CT and MRI Scans of a Chicken Wing LAA M
The Chicken Wing LAA morphology presents an obvious bend in the p
distance from the perceived LAA ostium. This type of LAA may have s
Figure 4 CT and MRI Scans of a Cauliflower LAA Morphology
The Cauliflower LAA morphology presents limited overall length with more complex internal characteristics. Variations of this LAA type have a more irregular shape
of the LAA ostium (oval vs. round) and a variable number of lobes with lack of a dominant lobe. CT (A) and MRI (B). Abbreviations as in Figure 1.
Figure 4 CT and MRI Scans of a Cauliflower LAA Morphology
The Cauliflower LAA morphology presents limited overall length with more complex internal characteristics. Variations of this LAA type have a more irregular shape
of the LAA ostium (oval vs. round) and a variable number of lobes with lack of a dominant lobe. CT (A) and MRI (B). Abbreviations as in Figure 1.
Cactus Chicken wing Wind sock Cauliflower
Wang Y et al. J Cardiovasc Electrophysiol 2010, 21; 973-982 Di Biase, D, et al. JACC 2012;60:531-8.
48% 3% 19% 30%

3. Background
• The risks associated with poorly fitting devices include
migration or embolization of the device, cardiac perforation,
LAA tear, pericardial effusion and residual leak.
• The rates of these complications have ranged from 2.2% to
9.9% in the clinical trials and registries of LAA closure devices
Large Leak

4. Background
• The LAA occlusion procedure is typically guided by 2-3D-TEE,
and fluoroscopy
• Correct sizing of the device remains a challenging phase of the
process, and any additional tool that minimizes the
manipulation inside the LAA and eases the implantation
process should be welcomed

5. Sizing and Implantation for Devices
is Based on 2D Echo
SH-300605-AA APR2015
Assess the following through multiple imaging planes (0 - 135 deg sweep):
• LAA size /shape, number of lobes in LAA and location of lobes relative to ostium
Record LAA ostium and LAA length measurements (0 - 135 deg sweep):
• Measure the LAA ostium at approximately these angles:
• at 0º
• at 45º
• at 90º measure from top of the MV annulus to a point 2cm from tip of the “limbus”
• at 135º
• Measure the approximate LAA usable length from the ostium line to the apex of the LAA
2. LAA Anatomy / Assessment
Ostium size and shape
measure from coronary artery marker to a point 2cm from tip of the “limbus”
SH-300605-AA APR2015
Maximum LAA
Os,um (mm)
Device Size (mm)
17-19 21
20-22 24
23-25 27
26-28 30
29-31 33
• Maximum LAA ostium and LAA depth
measurements determine device size selection
• Maximum LAA ostium size should be >17mm or
<31mm to accommodate available device sizes
• Available/useable LAA length should be equal to
or greater than the ostium
2. LAA Anatomy / Assessment
Proper device sizing
Physician training material for Watchman and Amulet devices

6. TAVI: 2D TEE vs MSCT
• Historically, 2D-TEE was the imaging modality of choice for TAVR
sizing
Mylotte D, et al. JACC Cardiovasc Interv. 2014; 7:652-661

7. Pre-Procedural CT-scan to Characterize the LAA
LAA
1.- Detailed LAA anatomy:
- Bends (location, angulation)
- Lobes, bifurcation
- Pectinate muscle/ridge/trabeculation
2.- Measure LAA dimensions
3.- Assess surrounding structures (septum, LA, PV, PA, etc.)
Selecting fluoroscopic angles
*3D volume rendering and printing
Saw J, et al. Can J Cardiol 2016;32:1033.e1-9.

8. Pre-Procedural CT-scan to Characterize the LAA
LAA
1.- Detailed LAA anatomy:
- Bends (location, angulation)
- Lobes, bifurcation
- Pectinate muscle/ridge/trabeculation
2.- Measure LAA dimensions
3.- Assess surrounding structures (septum, LA, PV, PA, etc.)
Selecting fluoroscopic angles
*3D volume rendering and printing
Saw J, et al. Can J Cardiol 2016;32:1033.e1-9.

9. Categorization of Left Atrial Appendage Morphologies is Too General

10. LAA Orifice Shapes
Oval Triangular Foot-like
Foot-like
Waterdrop-like
Round
68.9%
7.7%
10%
5.7%
7.7%
Wang Y, et al. J Cardiovasc Electrophysiol 2010;21:973-82.

11. Pre-Procedural CT-scan to Characterize the LAA
LAA
1.- Detailed LAA anatomy:
- Bends (location, angulation)
- Lobes, bifurcation
- Pectinate muscle/ridge/trabeculation
2.- Measure LAA dimensions
3.- Assess surrounding structures (septum, LA, PV, PA, etc.)
Selecting fluoroscopic angles
*3D volume rendering and printing
Saw J, et al. Can J Cardiol 2016;32:1033.e1-9.

12. Oa
Circumflex artery
Body Neck
Device size
Depth
Oa
d
1-2cm from PV ridge
Oe
b
a
10mm: ACP
15mm: Amulet,
Lambre
Assess LAA According to
Chosen Device

13. Measurements on MPR double-oblique
Watchman measurements
Amulet measurements

15. J Cardiovasc Electrophysiol. 2016

16. n of Cases CT machine CT measurements
Budge 2008 53 AF ablation 16-slice, 70%RR Segmented CT 2.5mm
larger than 2D-TEE
Lopez–Minguez
2014
37 ACP 64-slice, non-sync Supinf axis CT 0.95mm
larger than 2D-TEE
Saw 2016 50 LAA closure 320-detector or dual source
128-slice, 30-40% RR
MPR CT 1.8mm larger than
2D-TEE, 4.2mm larger than
fluoro
Rajwani 2016 73 LAA closure Dual source 128-slice MPR CT 3mm larger than
2D-TEE
Wang 2016 53 WM 128-slice + 3D printing 3D-CT 2.7mm larger than
2D-TEE, 2.3mm 3D-TEE
Saw J, et al. J Cardiovasc Electrophysiol 2016;27:414-22.
Rajwani A, et al. European Heart Journal - Cardiovascular Imaging 2016;0:1–8.
Wang DD, et al. JACC Cardiovasc Interv 2016;9:2329-40.
CT measurements were 2-3mm > than TEE
Budge LP, et al. J Interven Cardiac Electrophysiol 2008;23:87-93.
Lopez-Minguez JR, et al. J Invasive Cardiol 2014;26:462-467.

17. • 137 patients undergoing LAAO
• Comparing 2D and 3DTEE vs. CT
• 2DTEE had smaller LAA orifice measurements compared to 3DTEE
• 3DTEE had better correlation with CT
• 3DTEE smaller bias narrower limits of agreement with CT
Nucifora et al. Circ Cardiovasc Imaging 2011;4:514-523
r=0.92 r=0.72
3DTEE
2DTEE

18. In all 53 cases, only 1 device size was used for each case.

19. Pre-Procedural CT-scan to Characterize the LAA
LAA
1.- Detailed LAA anatomy:
- Bends (location, angulation)
- Lobes, bifurcation
- Pectinate muscle/ridge/trabeculation
2.- Measure LAA dimensions
3.- Assess surrounding structures (septum, LA, PV, PA, etc.)
Selecting fluoroscopic angles
*3D volume rendering and printing
Saw J, et al. Can J Cardiol 2016;32:1033.e1-9.

20. 3D-printed Models

21. 3D-Modeling

22. 3D-Modeling

23. 3D-Modeling

24. LAA ostium
Perimeter: 59.29mm

25. Perimeter: 59.03mm
Landing zone (10mm deeper the ostium)

26. Landing zone (12mm deeper the ostium)

27. Depth of LAA starting from the center point of
the LAA ostium

28. Minimum distance LAA ostium & mitral
annulus

29. Minimum distance LAA ostium & Superior
Pulmonary Vein

30. Minimum distance LAA ostium & Interatrial
Septum

31. Rev Esp Cardiol. 2017

32. Anatomical segmentation to isolate the
structures of interests based CT images
ITK-Snap (www.itksnap.org)
Volume render of segmented structures
of interest
3D printing workflow

33. The model was fabricated in polyurethane
filament by fused deposition
Computer aided design
(stl. file)
3D printer (BQ Witbox, Spain)
The 3D model was printed at 220ºC at 10 mm/s, with a layer
height of 0.1 mm, 0.8 mm wall thickness. Each LAA model
costs approximately 500 euros and the total process takes
24-48 hours.

34. Anatomical evaluation of the left atrial appendage at the level of the ostium, 10
mm and 15 mm distal.
Cross-sectional diameter evaluation at the level of the ostium.
Cross-sectional diameter evaluation 10 mm distal to the ostium
LAA measurements

35. 12 mm
55.02 mm
8.50 mm
Assess surrounding structures
Anterior view, distance to the mitral valve annulus
Posterior view, distance to the interatrial septum
Left lateral view, distance to the left upper pulmonary vein.

36. I
LAA
LAA
LAA
LAA
LAA
LAA
LAA
LA
LA
LA
LA
LA LA
LA
Cx
H
LAA
perimeter
G
LAA
LA
Multimodality imaging study of the left atrial appendage
Fluoroscopic projection TEE
CT CT left atrium volumen rendering
3D printed model

37. W
W
W
W
W
W
PV PV
PV
PV
PV
LA
LA
LA
In vitro rehearsal phase and final final result of left atrial appendage closure

38. A
LAA
LA
A B C D E
F G H I J
LAA
LAA
LAA
LAA
LAA
LAA
LAA
LAA
LAA
LAA
LA
LA
LA
LA
LA
LA
LA
LA
PV PV
PV
PV
PV
PV
AO
AO
In vitro rehearsal phase and final final result of left atrial appendage closure

39. Am
Am
Am
Pv
LA
LA
LA
Pv
Pv
Am
LA

40. Michaela M. Hell et al, EuroIntervention 2017;13:1234-1241
Twenty-two (22) patients (WATCHMAN device).
LAA was sized by TEE and third-generation dual-source CT and 3D printed models
Predicted device size based on simulated
implantation in the 3D model was equal to the
device finally implanted in 21/22 patients (95%).
TEE would have undersized the device in 10/22
patients (45%).

41. Obasare E et al, Int J Cardiovasc Imaging. 2017 Dec 8. doi:
24 patients underwent Watchman device (WD. All had complete 2-dimensional TEE.
14 also had cardiac computed tomography (CCT) with 3D printing to produce a latex
model of the LAA for pre-procedure planning.

42. • LAA anatomy can be complex and highly variable
• MSCT provides superior spatial resolution and 3-dimensional
depiction of LAA/surrounding structures
Summary LAA: MSCT
• Two-dimensional (2D-ETE or fluoroscopy) measurements are
smaller than those obtained from 3D images, which might
affect the accurate selection of the size of closure device

43. • For accurate device sizing in cases for whom selecting an
accurate size could be difficult (improve precision in closure
device sizing)
• For a better understanding of the inter-relationships between
anatomical structures of the LAA and the planning of
technical strategies with different devices
• For educational purposes to facilitate the understanding of
LAA anatomy and to clarify the aims and limitations of the
procedure
Summary LAA: 3D printed Models

44. Back up slides

45. Sup.
CAVA
LAA
SPV
LA
RA

46. Artificial Interatrial
Communication

47. SPVein
LAA orifice

48. Amulet 25mm, too small to cover the LAA orifice
SPVein SPVein

49. SPVein
Amulet 31mm, too big, entering in the SPVein