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El cateterismo del futuro: ¿ver y tocar? Antonio J Cartón Servicio de Cardiología Pediátrica Hospital Universitario La Paz Madrid, España h"p://www.cardiopa.aslapaz.com Necesidades percibidas h"p://www.cardiopa.aslapaz.com Visualización 3D de estructuras anatómicas h"p://www.cardiopa.aslapaz.com cross-sectional area of the stent at the smaller section,
stretching of the aortic root [18]. The aortic roots were
it wasan
moved
4.2 mm proximally
towards the left ventricle
devices were modelled using
elasto-plastic
con• obstruction of the coronary arteries, evaluated accord(EP; 3Fig. 4), and 4.2 mm distally towards the aortic arch
stitutive law (density 8,300 kg/m , Young’s modulus
ing to the minimum distance of the Sapien device/aortic
Table 1 summarises the number of Elements
elements used forModel
each of TAVI stent was drawn resembling(Ethe
; Edwards
Fig. 4).
Part
189,600 MPa, yield stress 760D MPa,
ultimate stress
valve leaflets from the coronary ostia,
The Sapien
stent TM
was designed in its expanded configmodel.
Sapien device;
theMPa).
presence
of the
valve wasframes
excluded
from
•
comparison of maximum principal stress distribution in
1,160
The
polymeric
of
Soprano
and
Patient-specific model
uration
this study. ThisTMstent is characterised by 12
units, and
eachcrimped onto the balloon to the size of the
the arterial walls.
Epic valves were described by
elasto-plastic
parameters
A
6,875
mm diameter) using a coaxial cylindrical sur2.2 Bioprosthetic aortic valves
formed by 4 zigzag elements 3 (Fig. 3). Acatheter
vertical(8bar
(density
9,120
kg/m
,
Young’s
modulus
2,840
MPa,
yield
B
8,675
face. The
stent
divides each unit and a perforated bar is positioned
every
4 deployment was divided into two different
stress 65.4 MPa, ultimate stress steps:
358 MPa).
C
11,325
balloon pressurisation (0.342 MPa) with resulting
a nominal
The metal frames of the four bioprosthetic
valves units.
were The TAVI device was chosen to have
The (=26
threemm)
aortic
valve
leaflets
wereexpansion
included
in the
each
FE and balloon deflation with
3 Results
stent
LVOT,
D
external diameter
[ the
internal
diameter
of the in
reconstructed from the CT images to8,347
identify their position
model of valves;
the prosthetic
valve.
Leaflets
ofthe
bovine
pericarsubsequent
stent
recoil.
In all patients, the LVOT/aortic
E
18,890
failing
bioprosthetic
the
height
and
thickness
of
Med
Biol
Eng
Comput
(2012)
50:183–192
inside the patients’ outflow tracts. Bioprosthetic valve
TM
At the end of all simulations, the TAVI stent was virtually
diumwere
origin
the root
Soprano
and(upper
Perimount
extremities
and lower aortic sections and corBioprostheses (stent ? DOI
leaflet)
expanded stent
16 are
andmounted
0.3 mm, on
respectively.
188
Med Biol Eng Comput (2012) 50:183–192
geometries were10.1007/s11517-012-0864-1
then re-drawn with CAD software
TM
implanted in the five patient-specific aortic root models.
onary
terminal
sections)
were constrained in all directions
Perimount Magna
44,048 ? 29,021
valves,
while of
porcine
leaflets
arewas
usedbased
in the
valve.
Mechanical
behaviour
the stent
material
on Epic
(Rhinoceros
4.0,
Robert
McNeel,
Seattle,
WA,
USA)
to
TM
O R I G I N A L A R T I C L51,372
E
Inside the four models with bioprosthetic valves (A–D), the
(circumferential,
radialwith
and alongitudinal) in order to mimic
Soprano
? 28,667
Both isotropic,
bovine and
porcine leaflets
were
simplified
a homogeneous,
elasto-plastic
austenitic
stainless
recreate a complete model of the corresponding
commer3
stent deployed symmetrically against the sewing rings and
connection
with
biological structures. Boundary conPerimount
44,048 ? 29,021
elastic
model (bovine:
1,120
kg/m
, Young’s
steel. The linear,
adopted
constitutive
law wasdensity
atheVon
Mises
cial device used in the patients, and
placed in the same
3
3
valve leaflets, with no contact with the native aortic wall
ditions
on
the
balloon
were
placed
to
mimic
the
bond
with
EpicTM
51,372 ? 28,667
plasticity model
(density
8,000
kg/m
,
Young’s
modulus
modulus 6 MPa; porcine: density 1,120 kg/m , Young’s
position as that identified from CT images. Each design
and/or other cardiac structure (Fig. 5). In model E, the
the catheter.
TAVI device
193,000
MPa,
yield
stress
205
MPa,
ultimate
stress
modulus
7.5
MPa)
by
elaborating
the
results
of
experiPatient-specific
simulations
transcatheter aortic valve stent
included
different
sewing rings and192,920
valve
leaflets: 515of
Sapien
stent
MPa) mental
with an studies
initial linear
elastic
response
followed
[19, 47]. Calcification of the leaflets was
implantation 8,160Magna valve by
Balloon
isotropic
behaviour
fromand thickness,
created
by hardening
increasing
Young’sobtained
modulus
• The Carpentier-Edwards Perimount
hada aplastic
Fig. 5 TAVI stent final configuration (end of balloon deflation) for models A–D and E
experimental
data [2]. ThetoMed
stent
withmm
192,920
186 of 2 mm in height with a rectangular,
Engmeshed
Comput
Fig.
450:183–192
Balloon
and TAVI
stentof
respectively,
10Biolwas
MPa
and (2012)
1.4
in the
region
lower ring
0.5
• E. Cerri • J. Nordmeyer
• elements, following mesh sensitivity
hexahedral
theanalysis.
three analysed positions
device assumed an asymmetrical configuration for the three
In models A–D, the axial connector elements repreCapelli •The
G. M.
Bosisupport
commissures [22], where ain
weld
constraint
was
also
mm thickC.section.
upper
had a circular 2.3the
positions, more open distally than proximally (EM in
senting the welding constraint caused by the calcification at
inside the native aortictested
valve:
TAVI device
Table
Mesh number •ofP.elements
of the parts
involved
in the FE •
• F.
T.1Odenwald
Bonhoeffer
Migliavacca
the leaflet commissure levels were broken during the
5).were
In all three cases, the interaction between the TAVI
applied; 16 connector elements
per commissure
sectionsimulations
with a diameter of 0.5 mm. The total height of
the central
section of Fig.
the stent
2.4 Balloon
A. M. Taylor • S. Schievano
system. Geometric orifice
and
placed
inassigned
correspondence
thethe native implantation site was well confined inflation of the stent–balloon
added.
An stent
axial,wasrigid
behaviour
was
todevice
theofthe
conof TAVI
drawn
resembling
the Edwards
the valve
Part was 14.5 mm and the diameter
Elements23 mm Model
area increased from 1.2 cm2 to 3.4 and 3.6 cm2 in models
within
LVOT
and
aortic
root
portion
of
the
patient’s
leaflet
commissures
(EM);
Sapien
device;
the
presence
of
the
valve
was
excluded
from
nectors,
allowing
to maintain
fixed
distancemorphology,
betweenthus reducing the potential risk of heart block A and B, respectively, and from 1.4 to 3.7 cm2 in models
(Fig. 2).
The geometry
of the
balloonthem
was drawn
in moved
thea expanded
4.2 mm proximally
Patient-specific model
2.3 TAVI mount
device
Table 1 Mesh number of elements of the parts involved in the FE
meshed with 3D triangular shell general-purpose elements.
simulations
Simulaciones (realidad virtual) M
Med Biol Eng Comput (2012) 50:183–192
this study. This stent is characterised by 12 units, each
and mitral valve leaflet entrapment.
C and D. The final geometric orifice areas in the three
);
towards
the bar
left ventricleStent
(EPradial
configuration
geometry
recoil was recorded after balloon deflation.
positions EM, EP and ED were, respectively, 4.7, 3.7 and
formedtobyresemble
4 zigzagthe
elements
(Fig.of3).the
A commercial
vertical
and, 4.2 mm distally towards
In all the models including bioprosthetic valves the maxi5.3 cm2 compared to an initial orifice of 3.7 cm2.
each
unit, and
a perforated
bar is positioned
4
balloon divides
(Z MED
IITM
NuMed
Inc., Hopkinton,
NY,every
USA)
the aortic arch (ED) mum recoil was measured in the distal sections towards the
The minimum distances between the closest stent strut/
C Received: 20 May 2011 / Accepted: 2 January
11,3252012 / Published
online:
29
January
2012was
Thepractice
TAVI
device
to have
a nominal
used in units.
clinical
[17].
Thechosen
nominal
length
of the
aortic arch (model A = 17.0%, model B = 13.2%, model
bioprosthetic valve leaflet and coronary ostia are reported
D ! International Federation for Medical and
8,347
Biological Engineering
2012
external
diameter
(=26
mm)
[
the
internal
diameter
of
the
C = 11.7%, model D = 10.8%). Recoil was absent or low
in Table 2. In none of the models, direct obstruction of the
expanded balloon was 50 mm; the cylindrical body that is
E
18,890
failing bioprosthetic valves; the height and thickness of the
proximally, at the level of the bioprosthetic valves’ annulus
coronaries occurred; neither the TAVI stent nor the bioin contact with the stent had a nominal diameter of
Bioprostheses (stent ? leaflet)
expanded stent were 16 and 0.3 mm, respectively.
(model A = 0.0%, model B = 1.7%, model C = 1.7%,
prosthetic valve leaflets occluded the ostia. The stent
were
higher
in
the
model
with
native
outflow
tract.
FE
Abstract
implantation
(TAVI)
21.85 mm
and
length
of
30
mm.
The
geometry
of
the
Perimount
MagnaTranscatheter aortic valve
44,048
? 29,021
model
D
=
0.0%).
In
the
model
with
the
native
valve,
the
positioned in model D was the closest (5.5 mm) to the
Mechanical behaviour of the stent material was based on
TM treatment of aortic stenosis with no need for open
recoil was measured proximally, in the portions
coronaries amongst those with bioprosthetic valves. The
analyses
canelasto-plastic
both
refineaustenitic
patient
selection andmaximum
characterise
enables
deflated a balloon
was
obtained
according
to previously
Soprano
51,372 ? 28,667
homogeneous,
isotropic,
stainless
of stent mostly interacting with the LVOTs (model
distal position of the stent implanted in model ED was
device constitutive
mechanicallaw
performance
TAVI, overall
impactheart surgery. According to current
only
Perimount
44,048 ?guidelines,
29,021
steel.
The[13].
adopted
was a VoninMises
published
work
EM = 14.9%;
the closest to the right coronary artery (3.1 mm)
amongst
188 model EP = 20.2%; model ED = 11.4%).
Med
Biol Eng Comput (2012) 50:183–192
TM
3
Epic
? 28,667
plasticity
(density
8,000
, Young’s
ing
on procedural
safety
in
the modulus
early
introduction
of perpatients
considered at high surgical 51,372
risk can
be A
treated
with model
homogeneous,
isotropic,
linearkg/m
elastic
Nylon11
was
the three positions tested.
The highest
Von Mises stresses occurred at the strut
3
TAVI
device In this study, patient-specific analyses were
193,000
MPa,
yield
stress
205
MPa,
ultimate
stress
In
all
models
with
bioprosthetic
valves,
the
principal
junctions
for
all
the
models.
The
maximum
reached
values
cutaneous
heart
valve
devices
in
new
patient
populations.
TAVI.
peradopted as per manufacturer’s data (density 1,256 kg/m ,
stress state in the aortic root reached the maximum value of
were included between 414 MPa (model ED) and 477 MPa
Sapien stent
192,920
515 MPa) with an initial linear elastic response followed
formed to explore the feasibility of TAVI
inYoung’s
morphologies,
modulus 450 MPa). The balloon was meshed with
0.1 MPa, while in model E the maximum principal stress in
(model EP, in Fig. 6). Stress values throughout the length of
123
Balloon
8,160
by a plastic isotropic hardening behaviour obtained from
Fig. 2 Carpentier-Edwards
Perimount
Magna bioprosthetic
Keywords
Stent
finite
element
analysis
!
Aortic
valve
which
are currently
borderlinevalve
casesFEfor a0.03
percutaneous
the LVOT was higher, showing how the implanted biothe stent zigzags and vertical bars were lower than 250 MPa.
mmexperimental
thick membrane
an average
size of
data [2].elements
The stent with
was meshed
with 192,920
model and dimensions (mm): lower (purple) and upper (blue) support
prostheses
act
as
a
scaffold
for
the
TAVI
stent.
By
comMaterial
plasticisation
occurred
at
the
points
of
maximum
stenosisfollowing
! Transcatheter
implantation
! Patient-specific
approach.
patients
were(yellow)
recruited:
with elements,
rings; valve leaflets (grey)
and Five
connector
elements
to four patients
hexahedral
mesh sensitivity
analysis.
paring the stress distribution induced by the three stent
stresses, i.e. at the junctions between zigzag and vertical
failed
bioprosthetic
valves (stenosis)
and
one
patientpatients’ aortic roots
simulate
the1calcification
(colour
figure
online)aorticreconstructions
positions in patient E, higher stresses were found in the
bars, thus guaranteeing a final open configuration of the stent.
Fig.
From left
to right,
3D volumetric
of the
five
selected
with an incompetent, native aortic valve. Three-dimen2.4 Balloon
sional models of the implantation sites were reconstructed
1 Introduction
Fig. 6 Von Mises stress
The geometry of the balloon was drawn in the expanded
computed
images. Within
these realistic
Fig.
5 TAVI
TAVIstent
stent final configuration (end of balloon deflation) for models A–D and EM
the two nodes until afrom
threshold
forcetomography
was reached—equal
to
distribution
in the
configuration to resemble the geometry of the commercial
after balloon valve
deflation in model
Aortic
stenosis
(AS)
is
currently
the
most
common
geometries,
TAVI
with
an
Edwards
Sapien
stent
was
0.92 N [22] along the direction joining the 2 nodes—and
EP
balloon (Z MED IITM, NuMed Inc., Hopkinton, NY, USA)
simulatedvalue
usingwas
finite
elementmimicking
(FE) modelling. Engineering
pathology in Europe and USA, where increased
lifeassumed an asymmetrical configuration for the three
device
In models A–D, the axial connector elements reprethen fail after this threshold
reached
used in clinical practice [17]. The nominal length of the
outcomes
assessed.
FE balloon
expectancy
is the
associated
degenerative
diseases
tested positions, more open distally than proximally (EM in
senting the welding constraint caused by the calcification at
expanded
was 50 mm;
cylindrical with
body that
is
calcification failure.and
Theclinical
thickening
and were
welding
of the In all patients,
affecting
cardiac
Surgical
valve replacethat TAVI
was orifice
morphologically feasible.
the leaflet commissure levels were broken during the
Fig. 5). In all three cases, the interaction between the TAVI
in contact with
the stent
had structures
a nominal [25].
diameter
of
failing valve leafletsanalysis
producedproved
aortic valve
geometric
inflation of the stent–balloon system. Geometric orifice
device and the native implantation site was well confined
21.85
mm and
length
of
30 considered
mm. The geometry
ofstandard
the
After
the
implantation,
stress
distribution
showed
no
risks
ment
has
been
the
gold
for
effectively
areas equal to those measured in the selected patients
area increased from 1.2 cm2 to 3.4 and 3.6 cm2 in models
withinofthe LVOT and aortic root portion of the patient’s
was AS
obtained
according the
to previously
of and
immediate
failure
and rigid
geometric orificedeflated
areas balloon
treating
[6]; however,
intrinsic invasive nature
(1.2 cm2 for A and B,
1.4 cm2device
for C and
D). The
morphology, thus reducing the potential risk of heart block
A and B, respectively, and from 1.4 to 3.7 cm2 in models
published
work
[13].
open heart surgery exposes patients to high risks and slow
increased
with lowusing
risk 8-node
of obstruction
supports of the valves
were meshed
linear of the coronary
and mitral valve leaflet entrapment.
C and D. The final geometric orifice areas in the three
A homogeneous, isotropic, linear elastic Nylon11 was
Maximum
principal
stresses
walls
recovery. Over the last decade, less invasive techniques
hexahedral elementsarteries.
with reduced
integration
with
a num-in the arterialadopted
Stent radial recoil was recorded after balloon deflation.
positions EM, EP and ED were, respectively, 4.7, 3.7 and
as per manufacturer’s data (density 1,256 kg/m3,
have450
been
introduced
to was
insert
cardiac
all the models including bioprosthetic valves the maxi5.3 cm2 compared to an initial orifice of 3.7 cm2.
Young’s modulus
MPa).
The balloon
meshed
withvalves usingIncatheber of elements varying
from
28,667
to
29,021
according
to
Fig. 2 Carpentier-Edwards Perimount Magna bioprosthetic valve FE
ter-based
In 2002,
the first intervention
mum recoil was measured in the distal sections towards the
The minimum distances between the closest stent strut/
0.03 mm thick
membraneinterventions
elements with [5].
an average
size of
the model (Tablemodel
1). The
valve leaflets
were
meshed
with
and dimensions
(mm): lower
(purple)
and upper
(blue) support
C. valve
Capellileaflets
and G.
M. Bosi
contributed
equally(yellow)
to this publication.
of transcatheter aortic valve implantation (TAVI)
was
aortic
arch (model A = 17.0%, model B = 13.2%, model
bioprosthetic valve leaflet and coronary ostia are reported
rings;
(grey)
and
connector
elements
to
4-node, quadrilateral, shell elements with reduced integra123
Fig.
3
CAD
model
and
dimensions
of
the
recreated
Edwards
Sapien
simulate the calcification (colour figure online)
= 11.7%, model D = 10.8%). Recoil was absent or low
in Table 2. In none of the models, direct obstruction of the
successfully performed [9]. The possibility to Creplace
tion and large-strainC.formulation
stent! (mm)
Capelli (&) (Fig.
! G. M.2).Bosi ! E. Cerri ! T. Odenwald
coronaries occurred; neither the TAVI stent nor the biocardiac valves using less invasive procedures has proximally,
been a at the level of the bioprosthetic valves’ annulus
P. Bonhoeffer ! A. M. Taylor ! S. Schievano
(model A = 0.0%, model B = 1.7%, model C = 1.7%,
prosthetic valve leaflets occluded the ostia. The stent
disruptive
innovation
and
has
revolutionised
the
treatment
for Cardiovascular
Institute of to
model D = 0.0%). In the model h"p://www.cardiopa.aslapaz.com with the native valve, the
positioned in model D was the closest (5.5 mm) to the
the Centre
two nodes
until a thresholdImaging,
force wasUCL
reached—equal
123
of
patients
with
severe
AS.
Almost
10
years
after
the
first
Cardiovascular Science, Great Ormond Street Hospital for
maximum recoil was measured proximally, in the portions
coronaries amongst those with bioprosthetic valves. The
0.92 N [22] along the direction joining the 2 nodes—and
Children, Great Ormond Street, London WC1N 3JH, UK
case, two devices are commercially available forofTAVI
then fail after this threshold value was reached mimicking
stent mostly interacting with the LVOTs (model
distal position of the stent implanted in model ED was
e-mail: [email protected]
(Edwards Sapien, Edwards Lifesciences, Irvine, CA,EMUSA;
calcification failure. The thickening and welding of the
the closest to the right coronary artery (3.1 mm) amongst
= 14.9%; model EP = 20.2%; model ED = 11.4%).
"
CoreValve , Medtronic, Minneapolis, MN, USA) The
withhighest Von Mises stresses occurred at the strut
failing
valve
leaflets
produced
aortic valve geometric orifice
the three positions tested.
G. M.
Bosi
! E. Cerri
! F. Migliavacca
areas
equal toofthose
measured
in the
selected Structural
patients
In all models with bioprosthetic valves, the principal
junctions for all the models. The maximum reached values
over 40,000 cases reported and over 200 studies published,
Laboratory
Biological
Structure
Mechanics,
A
B
6,875
8,675
123
h"p://www.cardiopa.aslapaz.com D
C
E
The
F
n e w e ng l a n d j o u r na
l o f m e dic i n e
Trachea
Carina
A
B
Aorta
SVC
D
C
G
E
F
Trachea
Carina
Figure 1. Placement of the Printed Airway Splint in the Patient.
Aorta
SVC
Panel A shows the airway in expiration before placement of the splint; the image was reformatted with minimumintensity projection. Panel B shows the patient-specific computed tomography–based design of the splint (red). Panel C
shows an image-based three-dimensional printed cast of the h"p://www.cardiopa.aslapaz.com patient’s airway without the splint in place, and Panel D
shows the cast with the splint in place. Panel E shows intraoperative placement of the splint (green arrow) overlying
the malacic left mainstem bronchial segment. SVC denotes superior vena cava. Panel F shows the bronchoscopic
view, from the carina, of the left mainstem bronchus after placement of the splint. Panel G shows the airway in ex-
Construcción de realidades tridimensionales ¡PODEMOS TOCAR!
h"p://www.cardiopa.aslapaz.com Impresión 3D C. Hull (3D Systems Corp, 1984)
h"p://www.cardiopa.aslapaz.com the workstation, 3D
segmentation and visualization
are performed and a
Computer-Aided Design (CAD)
model of the segmented
structures can be generated.
Such data can then be used by
rapid prototyping machines to
create the 3D solid object by the
addition of material layers
Impresión 3D Table 1 Overview of established rapid prototyping techniques used in the medical arena
Accuracy
Cost
Advantages
Disadvantages
Stereolithography (SLA)
+++
$$
Large part size
Moderate strength
Selective Laser Sintering (SLS)
++
$$$
Large part size, variety of materials, good strength
High cost, powdery surface
Fused Deposition Modeling (FDM)
++
$
Low cost, good strength
Low speed
Laminated Object Manufacturing (LOM)
+
$
Low cost, large part size
Limited materials
Inkjet printing techniques
+
$
Low cost, high speed, multimaterial capability
Moderate strength
The characteristics can vary depending on the specific printing system used
dispended by a piston, the parts of this layer belonging to
the 3D object are bonded by an adhesive liquid deposited by
another piston. Inkjet printing techniques can also be used to
generate a 3D scaffold with different types of tissue by printing living cells and biomaterials simultaneously [12,13].
Some fabrication techniques use two materials in the
course of constructing parts. The first material is the part
material and the second is the support material (to support
overhanging features during construction), the support material is later removed by heating or dissolved with a solvent
or water. This is not required in techniques where a powder
bed provides the support such as in SLS and inkjet printing techniques. Depending on the fabrication technique it is
also possible to combine materials of different elasticity or
color in one model. This can be useful to create more realistic
models for educational or research purposes, or for naturally
including individual patient care, research and as an educational and training tool.
Individual patient care
Surgical planning
Rapid prototyping has recently been introduced into the surgical arena as a tool for better understanding of complex
underlying anomaly. This can improve and facilitate the diagnostic quality and help in pre-surgical planning. Its application and benefith"p://www.cardiopa.aslapaz.com in craniofacial and maxillofacial surgery
[14–20] has been proven. First studies in pelvic surgery
[21,22], neurosurgery (Fig. 2) [23,24], spine surgery [25],
Adquisición de la imagen Alta resolución espacial: 0.5*0.5*0.5 mm
(TC)
Vóxels isotrópicos
Formato DICOM (Digital Imaging and
Communications in Medicine)
h"p://www.cardiopa.aslapaz.com Postprocesado Malla triangular 3D
Software CAD
Archivos DICOM
(datos crudos [raw data])
Modelo para
imprimir (Sterero
Lithography, .stl)
h"p://www.cardiopa.aslapaz.com Los problemas clínicos ¿PODEMOS PLANIFICAR MEJOR? ¿PODEMOS INVESTIGAR MEJOR? ¿PODEMOS ENSEÑAR MEJOR? ¿PODEMOS INTERVENIR MEJOR? Int J CARS (2010) 5:335–341
DOI 10.1007/s11548-010-0476-x
REVIEW ARTICLE
3D printing based on imaging data: review of medical applications
h"p://www.cardiopa.aslapaz.com F. Rengier · A. Mehndiratta · H. von Tengg-Kobligk ·
C. M. Zechmann · R. Unterhinninghofen ·
H.-U. Kauczor · F. L. Giesel
Fig. 1. The Fab@Home 3D printer connected to a laptop running Fab@Home
V_0.21 software.
CAD model can be seen in Fig. 2b. The geometry of the
sinuses of Valsalva was modeled partially following the
ARTICLE IN PRESS
description of Reul and colleagues w15x and was treated as
an epitrochoid. ‘An epitrochoid is a roulette traced by a
doi:10.1510/icvts.2008.194134
point attached to a circle of radius r rolling around the
outside of a fixed circle of radius R, where the point is a
distance d from the center of the exterior circle’ – defiInteractive CardioVascular and Thoracic Surgery 8 (2009) 182–186
nition of an epitrochoid from www.wikipedia.org. In brief
www.icvts.org
the sinuses were described as an epitrochoid with an
Work in progress report - Experimental
Rs13.2 mm, rs4.4 mm and ds2.8 mm (Fig. 3). It has to
Rapid prototyping of compliant human aortic roots for
be noted that in order to have three sinuses R has to be
Rapid
prototyping
of compliant,
life-size anatomical models with
LE IN PRESS
equal to 3r. The X,
Y coordinates
the respective curve
assessment of valved stents
ARTICLE
IN ofPRESS
the
3D
printer
is
feasible
– it is very quick compared
wereFab@Home
calculated in Microsoft
Excel software
using the
ARTICLE INMartins
PRESS
Kalejs*, Ludwig183
Karl von Segesser
CardioVascular and Thoracic Surgery 8 (2009) 182–186
equations which can be seen in Fig. 3. Later the calculated
previous
casting
methods.
M.to
Kalejs,
L.K. von Segesser
/ Interactive CardioVascular
and Thoracic Surgery 8 (2009) 182–186
183
Department of Cardio-Vascular Surgery, Centre Hospitalier Universitaire Vaudois, CHUV, Rue du Bugnon 46, CH-1011 Lausanne, Lausanne, Switzerland
points were saved in an ASCII text file as X, Y, Z coordinates
M. Kalejs, L.K. von Segesser / Interactive CardioVascular and Thoracic Surgery 8 (2009) 182–186
183
Received 15 September 2008; accepted 15 October 2008
and imported into SolidWorks.
Abstract
The model geometry was saved in STL format (Stereolithography) and printed using an open-source rapid prototyping
Adequate in-vitro training in valved stents deployment as well as testing of the latter devices requires compliant real-size models of the
human aortic root. The casting methods utilized up to now are multi-step, time consuming and complicated. We pursued a goal of building
system developed by the Fab@Home project (http:yyfabaa flexible 3D model in a single-step procedure. We created a precise 3D CAD model of a human aortic root using previously published
anatomical and geometrical data and printed it using a novel rapid prototyping system developed by the Fab@Home project. As a material
thome.orgy) and distributed by Koba Industries (Albuquerfor 3D fabrication we used common house-hold silicone and afterwards dip-coated several models with dispersion silicone one or two times.
que, NM, USA) which main components are a deposition
To assess the production precision we compared the size of the final product with the CAD model. Compliance of the models was measured
and compared with native porcine aortic root. Total fabrication time was 3 h and 20 min. Dip-coating one or two times with dispersion
tool with a syringe moved by several stepper motors. For
silicone if applied took one or two extra days, respectively. The error in dimensions of non-coated aortic root model compared to the CAD
printing we used a syringe tip with a diameter of 0.84 mm.
design was -3.0% along X, Y-axes and 4.1% along Z-axis. Compliance of a non-coated model as judged by the changes of radius values in
the radial direction by 16.39% is significantly different (P-0.001) from native aortic tissue – 23.54% at the pressure of 80–100 mmHg.
The printing setup can be seen on Fig. 1. As a material for
Rapid prototyping of compliant, life-size anatomical models with the Fab@Home 3D printer is feasible – it is very quick compared to
previous casting methods.
3D fabrication we used common house-hold (sanitary) sili! 2009 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.
cone (Forbo international, Schoenenwerd, Switzerland)
Keywords: Aortic root; 3D print; Stereolitography; Stent valve; Trancatheter valve replacement
which took around 4 h to dry and is semitransparent.
Afterwards we dip-coated several models with dispersion
silicone
Technology,
Carpinteria,
USA) one
or two
M. Kalejs, L.K. von ering
Segesser
/ Interactive CardioVascular
and(Nusil
Thoracic
Surgery
8 CA,
(2009)
182–186
1. Introduction
the rapid advancement of transcatheter procedures
w12x, there is a certain need for flexible hollow models e.g.
times making a pause of at least 16 h between dipping to
With advancement of diagnostic imaging techniques capaa model of aorta or aortic root for endovascular and valvedallow the previous layer to dry completely.
ble of producing three-dimensional virtual reconstructions
stents procedures training and new device testing.
of human body parts from stacks of multi-planar images,
We compared the elastic properties of the constructed
There are several methods to create such models but all
3D imaging has rapidly entered the clinical world. It is used
of them include several steps and are time consuming. The
models with a fresh porcine aortic root harvested within
routinely not just for diagnostic purposes but also for
most
detailed
and
precise
flexible
models
can
be
made
by
ome 3D printer connected to a laptop running Fab@Home
Fig. 1. The Fab@Home 3D printer 6
connected
a laptop running
intervention planning and guidance in fields of radiology,
h posttomortem.
We Fab@Home
performed a test using a roller pump
combining rapid prototyping for creating molds and tradime
V_0.21 software.
neurosurgery and cranio-facial surgery w1–3x. The before
tional casting of silicone w5, 13x. Recently, a new rapid
Fig. 2. (a) View of the CAD design of the aortic root in Solidworks 2008 SE
to
pressurize
the
models
with three sonomicrometry probes
mentioned specialties were pioneering this field, but very
prototyping system has become available, created by the
software (see Video 1 for a rotation view of the model in 3D); (b) Dimensions
quickly the benefits provided by 3D visualization were
(Sonometrics,
London,
Canada)
fixed
on
the
outer
surface
Fab@Home project (Fig. 1) which to our best knowledge is
in millimeters of the CAD design compared to the dimensions of final product
appreciated
and accepted
n be seen in Fig. 2b.
The geometry
of also
the by other medical specialties
the only 3D printer capable of using any viscous substance
the2b.
models
at the level
of commissures. Mathematical
CAD model can be seen inofFig.
The geometry
of the
(after slash). (c) View of the final product – a flexible life-size aortic root
including cardiologists and cardiovascular surgeons. It is
as a building material.
salva
was
modeled
partially
following
the
he
being used for diagnostic purposes, for operation planning
analysis of
the data
was performed
off-line with a software
model made in silicone.
sinuses
of forValsalva was modeled
partially
following
the
Aiming to reduce the complexity and time
needed
w
x
Reul
and
colleagues
15
and
was
treated
as
w
x
as well as for education and training 4–7 .
he
creating a compliant physical model ofdescription
aortic root we
of Reul and colleagues w15x and was treated as
More
recently traced
with decreasing
. ‘An epitrochoid is a
roulette
by a prices and increasing overdecided to pursue a goal of building a 3D model in a singleas
an epitrochoid. ‘An epitrochoid is a roulette traced by a
all popularity and availability of rapid prototyping devices
step procedure without employing the somewhat time
d to a circle of radius
r rolling around the
also called 3D printers, the virtual 3D representation on
a
point
attached to a circle of radius r rolling around the
consuming and rather unpredictable casting
techniques.
xed circle of radius the
R, where
thefound
pointitsisrealization
a
screen has
in solid replica of
outside of a fixed circle of radius R, where the point is a
he
m the center of theanatomical
exterior structures
circle’ –– life-size,
defi- rigid physical models w8–
2. Materials and methods
distance d from the center of the exterior circle’ – defia
11x which contribute In
to brief
the realism, facilitate perception
pitrochoid
from www.wikipedia.org.
and recognition of the 3D structures w10x, hence improving
nition
of an epitrochoid from www.wikipedia.org. In brief
iWe used Solidworks 2008 SE (SolidWorks
Corporation,
ere described as an
epitrochoid
w9x. In an
clinical
performancewith
cardiovascular surgery, considConcord, MA, USA) for creating a precise 3D
model
(Fig. 2a were described as an epitrochoid with an
the
sinuses
ef
s4.4 mm and ds2.8 mm (Fig. 3). It has to
and Video 1) of the aortic root in silico Rs13.2
using previously
*Corresponding author. Center of Cardiac Surgery, Pauls Stradins Clinical
mm, rs4.4 mm and ds2.8 mm (Fig. 3). It has to
sinuses
R
has
to
be
anin order to have three
published
anatomical
and
geometrical
data
with
minimal
University Hospital, Pilsonu str. 13, Riga, LV-1002, Latvia.
bein noted
modifications w14, 15x. The dimensions used
creating that
the in order to have three sinuses R has to be
E-mail
address:
[email protected]
he X, Y coordinates of
the
respective
curve (M. Kalejs).
to
! 2009software
Published by European
equal to 3r. The X, Y coordinates of the respective curve
ed in Microsoft Excel
usingAssociation
the for Cardio-Thoracic Surgery
be
were calculated in Microsoft Excel software using the
h can be seen in Fig. 3. Later the calculated
ve
equations which can be seen in Fig. 3. Later the calculated
ved in an ASCII text file as X, Y, Z coordinates
he
points were saved in an ASCII text file as X, Y, Z coordinates
nto SolidWorks.
ed
ideo
1. saved
A rotation
of the aortic root CAD model in 3D. and imported into SolidWorks.
Video 2. A time-lapse movie of rapid prototyping of an aortic root using the
ometry was
in STL formatview
(Stereolithoes
inted using an open-source rapid prototyping
The model geometry was saved in STL format (Stereolitho-
ped by the Fab@Home project (http:yyfabaond distributed by Koba Industries (Albuquer) which main components are a deposition
ng
ringe moved by several stepper motors. For
aed
r- a syringe tip with a diameter of 0.84 mm.
etup can be seen on Fig. 1. As a material for
on
we used common house-hold (sanitary) silior
international, Schoenenwerd, Switzerland)
ARTICLE IN PRESS
Fab@Home 3D printer.
graphy) and printed using an open-source rapid prototyping
system developed by the Fab@Home project (http:yyfabathome.orgy) and distributed by Koba Industries (Albuquerque, NM, USA) which main components are a deposition
tool with a syringe moved by several stepper motors. For
printing we used a syringe tip with a diameter of 0.84 mm.
The printing setup can be seen on Fig. 1. As a material for
h"p://www.cardiopa.aslapaz.com To prove the appropriateness of the built mockup for close
to real-life simulations in artificial circulatory systems we
In inspection
two patients,
models
were
used for aneurysmecheart and the use of the model during the surgical proceintraoperativel
of thethe
ventricle
leads
to identification
of scarred
dure influenced preoperative planning and facilitated the tomy
and
LV reshaping
(Fig.
4). Preoperative
measand
viable
myocardium.
Transmural
palpation LVESV,
of contractkinetic volume
2 non-viable
operation. Due to the massive volume of the tumor and uredingby
muscle
delineates the junction
of viable
and
echocardiography,
was 139.9
mlym
and 125.0
the template c
2
the infiltration to the tricuspid valve (Fig. 3), the access mlym
tissue.
An
encircling
suture
at
this
junction
excludes
the
. The surgeon could reshape the LV around the
reshaping the
to the target was chosen through the right ventricle instead residual
scar from
thetemplate
ventricular
cavity
anddecrease
creates the
a pursed
volume
(Fig.
1) and
LVESV
dimensional (2
IN PRESS A complete mass reducof access through theARTICLE
right atrium.
opening. A Dacron patch is secured onto this opening and
tion of the histological poor differentiated sarcoma was
eliminates the akinetic or dyskinetic segment w12x. The
achieved including the tricuspid valve, which had to be
identification of the scarred and viable tissue on the
replaced. Due to enabling identification of risk structures
arrested or fibrillating heart is based on experience but
like the right ventricular wall and the right ventricular
misidentification can occur. In addition, creation of an
Work in progress report - Experimental
outflow tract (RVOT), the surgeon was guided through the
elliptical ventricle is demanding. Standardized preshaped
3D-Imaging of cardiac structures using 3D heart models for planning
operation andin could
determine
the
malignant
tissue
(distinelliptical balloons (Chase Medical, Dallas, TX; The Blue
heart surgery: a preliminary study
guish myocardium
andGrunert
malignant
tissue).
Afterwards a
Egg!, BioVentrix) may help to size and configure the
Stephan Jacobs *, Ronny
, Friedrich W. Mohr
, Volkmar Falk
echocardio8 Cryoablation was done. Postoperatively
S. Jacobs et al.the
/ Interactive
CardioVascular
and Thoracic
Surgery
7 (2008)a6–9
ventricle,
but do
not provide
patient’s individual solution.
graphy showed properly the size of the right ventricle with
The 3D RPT method tries to support the transfer of 2D
Abstract
no obstruction of the RVOT.
images
into
a 1:1
geometric
model,
which can beThese
used resid2
2
to 64.5
mlym
and
58.3 mlym
postoperatively.
The aim of the study was to create an anatomical correct 3D rapid prototyping model (RPT) for patients with complex heart disease and
In
two
patients,
the
models
were
used
for
aneurysmecintraoperatively.
Once
the
viable
ventricular
cavity
(rest
altered geometry of the atria or ventricles to facilitate planning and execution of the surgical procedure. Based on computer tomography
ual volumes are in line with the current literature w11x.
(CT) and magnetic resonance imaging (MRI) images, regions of interest were segmented using the Mimics 9.0 software (Materialise, Leuven,
Belgium).
The segmented
were the target volume (Fig.
and structures
at risk.Preoperative
After generating an STL-file (StereoLithography
file) out
tomy
and regions
LV reshaping
4).
LVESV, measkinetic volume of the LV) is printed out as a RPT model,
of the patient’s data set, the 3D printer Z" 510 (4D Concepts, Gross-Gerau, Germany) created a 3D plaster model. The patient individual
The postoperative images show a complete resection of the
3Dured
printed RPT-models
used to plan the resection of a left ventricular
aneurysm139.9
and right ventricular
tumor.2The and
surgeon was 125.0
able to
by wereechocardiography,
was
mlym
the template can potentially be used for patient individual
identify risk structures, assess the ideal resection lines and determine the residual shape after a reconstructive procedure (LV remodelling,
akinetic and dyskinetic target tissue and an elliptical veninfiltrating tumor
resection).
Using
a
3D-print
of
the
LV-aneurysm,
reshaping
of
the
left
ventricle
ensuring
sufficient
LV
volume
was
easily
mlym2The. useThe
could
the aneurysm
LV and
around
the
reshaping the left ventricle. This method converts a twoaccomplished.
of the 3D surgeon
rapid prototyping model
(RPT-model) reshape
during resection of ventricular
malignant cardiac
tumors may facilitate the surgical procedure due to better planning and improved orientation.
tricular geometry.
!residual
2008 Published by European
Association template
for Cardio-Thoracic Surgery.
All rights1)
reserved.
volume
(Fig.
and decrease the LVESV
dimensional
(2D) image into a three-dimensional (3D) strucdoi:10.1510/icvts.2007.156588
Interactive CardioVascular and Thoracic Surgery 7 (2008) 6–9
www.icvts.org
ARTICLE IN PRESS
a,
b
a
a
Herzzentrum Leipzig, Department of Cardiac Surgery, University Leipzig, Germany
b
Innovation Center Computer Assisted Surgery, Leipzig, Germany
a
Received 25 March 2007; received in revised form 15 September 2007; accepted 17 September 2007
The time to segment the CT data set semi-automatically
with a layer thickness of 0.5 mm took about 3 h compared
1. Introduction
will be limited w4x. Beside the rest volume of the ventricle,
the geometry is important. Ventricular volume should be
Fig. 3. Rapid
prototyping
model showsperformed
a massive cardiac-tumor
infiltrato the
segmentation
manuallywith
with
a layer Fig. 4. Rapid proto
The use of imaging techniques for preoperative planning
reduced in its septal and anterior components without
is helpful to improve the results of complex surgical
tion to thickness
the right ventricular
wall
and
the
tricuspid
valve.
deforming the chamber. In normal hearts, myocardial fibers
of 0.5 mm which took about 8 h. The segmenta- Segmentation was
interventions.
have a spiral direction from the base to the apex with two
opposite layers and well-defined intersection angles w5x.
tion performed manually with a layer thickness of 1.0 mm
When the spiral architecture is lost due to resection of the
1.1. Congestive heart failure and ventricular aneurysm
aneurysm especially at the apex, ventricular function is
In case of anterior myocardial infarction, the ventricular
impaired and ejection fraction and stroke volume decrease.
required 5 h.
shape and volume changes w1x and there is loss of contracAn elliptical ventricle decreases lateral force (stress)
tion of the anterior wall and septum. Ventricular dysfunccompared to a longitudinal one with a spherical rounded
Quality of resolution of the semi-automatically segmented
tion and eventually aneurysm formation may lead to
apex w6x. Standardized preshaped elliptical balloons (Chase
congestive heart failure (CHF). Surgical methods for aneuMedical, Dallas, TX; The Blue Egg", BioVentrix) have
CT
data set and the coarsely layered thickness of 1.0 mm
w
x
rysm resection and left ventricular reshaping vary from
helped to size and configure the ventricle 7 .
volume reduction only if a dyskinetic scar is present, to
1.2.
Cardiac
tumors
surgical repair of the postinfarction dyskinetic, dilated
was unsurprisingly less. Regarding time needed for segmenventricle with simple excision and closure to Jatene’s
Primary tumors of the heart are exceedingly rare. The
septal exclusion technique w2x. In 1984, Dor et al. w3x
tation and quality of target area and structures at risk,
angiosarcoma is the most common primary malignant tumor
reduction of ventricular size by excluding the
of the heart in models
adults with a uniformly
prognosis
.
Fig.suggested
2. 3D
solid anatomical rapid prototyping
(RPT)dismal
show
anw8xinside
non-contracting segment with an intraventricular patch. If
Besides echocardiography, magnetic resonance imaging and
only segmentation performed manually with a layer thickthe residual
volume is too
small, the resultcardiac
will be cata-structures with the aneurysm and the LVview
of resulting
patients
computed tomography
are beneficial
in the diagnostic
The
use
ofindividual
the
3D
rapid
prototyping
model
(RPT-model)
strophic,
in the
physiology
of a restricted
cardiowork-up w9x. These imaging modalities are particularly
myopathy. If the residual chamber
is too large,was
the benefit
ness of 0.5 mm showed acceptable results in terms of
residual-volume.
The model
segmented
out
a cardiac
datatumors
set with
helpful in manually
defining the extent
to of
which
during resection
of ventricular
aneurysm
and
malignant
infiltrate surrounding structures. Complete surgical reseca layer thickness of 0.5 mm.
w
x
identifying all target areas and structures at risk.
is required for improved survival 10 . However, by its
cardiac tumors may facilitatetionthe
surgical procedure due
Keywords: Imaging; Ventricular remodeling; Cardiac tumor; 3D print
*Corresponding author. Klinik für Herzchirurgie, Universität Leipzig, Herzzentrum, Strümpellstr. 39, 04289 Leipzig, Germany. Tel.:q49-341-865-1433;
fax: q49-341-865-1452.
E-mail address: [email protected] (S. Jacobs).
very location, radical complete resection is rarely possible.
Optimal management strategies have not been defined
to better planning and improved orientation.
3. Results
! 2008 Published by European Association for Cardio-Thoracic Surgery
Fig. 3. Rapid prototyping model shows a massive cardiac-tumor with infiltration comparison
to the right ventricular
the tricuspid
The
of thewall
3Dand
heart
modelvalve.
with the real open
heart and the use of the model during the surgical procedure influenced preoperative planning and facilitated the
operation. Due to the massive volume of the tumor and
the infiltration to the tricuspid valve (Fig. 3), the access
4. Discussion
Fig. 4. Rapid prototyping model shows an enlarged LV with an aneurysm.
Segmentation
was performed
manually with a layer thickness
of 1.0 mm.
Performing
an aneurysmectomy
or Dor-plasty,
visual
inspection of the h"p://www.cardiopa.aslapaz.com ventricle leads to identification of scarred
and viable myocardium. Transmural palpation of contracting muscle delineates the junction of viable and non-viable
tissue. An encircling suture at this junction excludes the
h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com h"p://www.cardiopa.aslapaz.com Comentarios El protoVpado tridimensional de estructuras anatómicas es posible a parVr de los datos de pruebas radiológicas indicadas clínicamente. Existe un potencial enorme de planificación, invesVgación, docencia y mejora de intervenciones sobre nuestros complejos pacientes. h"p://www.cardiopa.aslapaz.com