Multi-Detector Row Computed Tomography

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Nov 15, 2013 (3 years and 10 months ago)

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Online Appendix for the following
JACC: Cardiovascular Imaging

article

TITLE:

Automated 3
-
Dimensional Analysis of Pre
-
Procedural Multidetector Row Computed
Tomography to Predict Annulus Plane Angulation and C
-
Arm Positioning
:
Benefit on
Procedural Outcome
in Patients Referred for Transcatheter Aortic Valve Replacement


AUTHORS:

Mariam Samim, BS
C
, Pieter R. Stella, MD, P
H
D, Pierfrancesco Agostoni, MD,
P
H
D, Jolanda Kluin, MD, P
H
D, Faiez Ramjankhan, MD, Ricardo P. J. Budde, MD, P
H
D,
Gertjan Sieswerda, MD, P
H
D,

Emanuela
Algeri
, MD, Camille van Belle, BS
C
,
Ahmed
Elkalioubie
, MD, Francis Juthier, MD,
Anouar Belkacemi, MD
, Michel E. Bertrand, MD,
Pieter A. Doevendans
, MD, P
H
D, Eric van Belle, MD, P
H
D

METHODS


Multi
-
Detector Row Computed T
omography

Pre
-
procedurally,

a
l
l

patients underwent a

contrast enhanced retrospectively ECG
-
gated
MDCT

scan on either a

64
-

or 256
-
slice scanner (Brilliance 64 or iCT, respectively,
Philips Medical Systems, Best, the Netherlands), according to standard scan protocols that
were indivi
dually adjusted based on patient body habitus. Tube voltage was 100 or 120 kV,
tube current 200
-
400 mAs, collimation
64

or 128

x 0.
625 mm and ga
ntry rotation time of
270
-
420 ms
.

The scan range was set from the level of the subclavian arteries to the level
of the
head of the femur. A continuous ECG trace was recorded during image acquisition and
images were reconstructed at each 12.5% of the R
-
R interval, obtaining a total of 8 datasets
per scan (including 37.5% for systole and 75% for diastole).


All scans

were performed during mid
-
inspiratory breath
-
hold, and
during injection of
iodinated non
-
ionic contrast agent
(
Ultravist

iopromide
-

300 mg/m
L
, Bayer Schering Pharma
AG, Berlin, Germany
,

Healthcare Tarrytown, New York)
.

B
eta
-
blockers

were

not routinely

adm
inistered
prior to scanning.


Data sets were reconstructed and off
-
line post
-
processing of
MDCT

images was
performed on

a

dedicated workstation.


Automated
3D
Image
A
nalysis

of M
DCT


The
MDCT

data were sent to an external workstation for dedicated analysis
.
A
ll scans
were an
alyzed using a software package and
a dedicated 3D aortic valve analysis workflow

(3mensio Valves
TM
, 3mensio Medical Imaging BV, The Netherlands,
http://www.3mensio.com
)
.
Early systolic images of t
he aortic root reconstructed at 30

to
3
7.
5% of the R
-
R interval were selected
,

as recommended.

The first step of the valve analysis workflow is an automatic segmentation of the
ascending aorta. Alternatively
,
placing control points in the aorta, the aortic

valve, and in the
left ventricle
will manually create

a centerline.

The application now provides an estimated
aortic annulus plane location and orientation. In the next step of the workflow
,

these must be
refined. This can be done by positioning and rotat
ing the annulus plane as depicted in Figure 2

in order to define the plane that permits the identification of the 3 aortic sinuses
4
.

In the final step of the workflow
,

the latero
-
lateral (LAO, RAO)

and cranio
-
caudal
angles required for
a perpendicular
orient
ation of

the C
-
Arm to the aortic annulus plane are
determined. This is done by rotating a virtual C
-
Arm around the aortic centerline at the
intersection point with the annulus plane (Figure 2B).
A simulated angiogram is interactively
updated when the virtual C
-
Arm is rotated. The respective images are displayed on

the

screen.


TAVR

procedure

TEE was used for all procedures. Patients were premedicated with aspirin and
antibiotics. Heparin was used

to maintain

an activated clotting time >250

sec. The ACT was
reversed with protamine at the end of the procedure.

Both for the TF and TA
-
AVR

approach, the device
-
delivering sheath was inserted
before crossing the valve with any wire. Intra
-
procedural ima
ging of the aortic valve was
achieved by contrast
injection
via a pigtail catheter
, which was positioned

just above the valve
itself and introduced via a femoral artery (the contralateral in

the

case of TF
-
AVR
). Balloon
aortic valvuloplasty with a 20
-

or 2
3
-
mm balloon was performed under rapid pacing to pre
-
dilate the native aortic valve. The prosthesis was subsequently deployed under rapid pacing
(180 to 220 beats/min). Exit peripheral angiography was performed to ensure no extravasation
of contrast prior
to removal of
the
femoral sheath.
Immediately post
-
procedure, t
he sheath
was removed and surgically closed in the operating room by a surgeon
or by using 2
percutaneous closure devices (Perclose, ProGlide, Abbott Vascular)
.

For
the purpose of rapid ventric
ular pacing

during TA
-
AVR
, two unipolar epicardial
pacer wires were secured and tested with a high output epicardial pacing system to ensure
ventricular capture at rates of 180
-
220 bpm.

Procedural success was defined as the implantation of a functional pro
sthetic valve
within the aortic annulus at the end of the procedure without in
-
laboratory mortality. Patients
received aspirin (81 mg/day) and clopidogrel (75 mg/day) indefinitely. Warfarin was
substituted for
clopidogrel

in patients with atrial fibrillati
on.