Medtronic Endurant Manual Del Usuario página 23

2011/DEC/22 at 7:46 p.m. Doc number: M716803B001 [multi23]
•
Disengage the rear handle by pressing the tips of the hemostats into the handle disassembly
ports and simultaneously retracting the rear handle from the delivery system.
•
Stabilize the delivery system.
•
Manually push up the back-end T-tube to deploy the tip captured crowns and anchoring pins of
the suprarenal stent.
•
Manually pull back the back-end T-tube to recapture the taper tip after the deployment.
•
Follow the standard instruction for use for delivery system removal.
•
Hold the back-end wheel component so that it remains retracted and the taper tip recaptured
during delivery system removal.
9.8.4. Snare the Taper Tip
In the unlikely event of delivery system failure and concomitant no or partial deployment of the proximal
end of crowns and anchoring pins of the suprarenal stent due to back-end wheel failure, and a "back-end
handle disassembly" technique in Section 9.8.3 cannot give successful deployment of the proximal end
of crowns and anchoring pins of the suprarenal stent due to the excessively high deployment force, a
"snare the taper tip" technique may permit the successful deployment of the proximal end of crowns and
anchoring pins of the suprarenal stent. See the instructions below.
•
Use a snare device.
•
Advance the snare device to the delivery system taper tip section through upper torso access,
i.e. brachial.
•
Utilize fluoroscopy to snare the edge of the delivery system taper tip.
•
Stabilize the delivery system, especially the back end section.
•
Pull the snare device to separate the suprarenal stent from the tip capture.
•
Manually pull back the back-end T-tube to recapture the taper tip after the deployment.
•
Follow the standard instruction for use for delivery system removal.
•
Ensure that the back-end T-tube remains retracted and the taper tip recaptured during delivery
system removal.
9.9. Follow-up Imaging Recommendations
9.9.1. General
Current imaging of stent graft patients includes abdominal X-ray and spiral CT, with and without contrast
medium. Alternative imaging modalities such as color Doppler ultrasound and magnetic resonance
imaging should be used in patients with impaired renal function or intolerance to contrast media.
Imaging should be decided based upon the physician's clinical assessment of the patient pre- and post-
implantation of the stent graft.
9.9.2. X-ray
Abdominal X-rays should be used to assess the presence of stent graft fracture. Posterior/anterior (PA)
and lateral images are recommended for visualization of the stent graft. Ensure that all components of the
device are captured on images for device assessment.
9.9.3. Spiral CT with Contrast
Spiral CT with contrast medium should be used to assess stent graft fixation, deformation, apposition to
the vessel wall at proximal and distal fixation sites, stent graft migration, stent graft patency, AAA size,
occlusion of branch vessels, and endoleak (including source and type if present). The preferred imaging
study uses 3 mm to 5 mm collimation, 2 mm to 3 mm reformat intervals, with coverage from the celiac
artery to the external iliac or femoral arteries during "arterial phase" contrast. For calcifications or areas
where metal artifacts may be misinterpreted as endoleak, a non-contrast CT scan should be performed
first, using thicker collimation (10 mm) to avoid tube overheating. In aneurysms that are not shrinking but
have no apparent endoleak or fixation problems, a delayed or "venous phase" scan may be performed
immediately following the "arterial phase" scan. The delayed "venous phase" scan may also be performed
with thicker collimation (10 mm) if tube overheating is a concern. This is referred to as the "three-phase"
technique. It is recommended that the full electronic data set be archived in case specialized evaluation
is needed later (volume measurements, three-dimensional reconstruction and/or computer aided
measurement software). If the aneurysm is not shrinking by more than 5 mm within the first year, volume
measurements may be obtained as a more sensitive indicator of AAA size using commercial software.
9.9.4. Spiral CT without Contrast
For patients with impaired renal function, a spiral CT without contrast may be considered to assess stent
graft fixation, deformation, apposition to the vessel wall at proximal and distal fixation sites, stent graft
migration, occlusion of vessels, and size of the AAA with diameter and volume measurements. For
aneurysms that are not clearly shrinking, an adjunctive color Doppler ultrasound may be considered to
evaluate a possible endoleak (including source and type, if present).
9.9.5. MRI or MRA
Patients with impaired renal function, i.e. renal insufficiency, may also be considered for magnetic
resonance imaging or angiography (MRI, MRA) in facilities that have expertise in this area. Artifact may
occur related to the stent, and care should be used to insure adequate imaging of the outer aneurysm wall
to assess AAA size. Volume measurement may be helpful if the aneurysm is not clearly shrinking. If there
are concerns regarding imaging of calcified areas, fixation sites, or the outer wall of the aneurysm sac,
adjunctive CT without contrast may be needed. If there are difficulties imaging a possible endoleak, color
Doppler ultrasound may be considered.
9.9.6. Duplex Color Doppler Ultrasound
Duplex Color Doppler Ultrasound (CDUS) may be used to assess AAA size, exclusion of the aneurysm
and endoleak type. This may be an alternative imaging modality for patients with impaired renal function
in a facility with adequate technologist skill and training. An ICAVL approved vascular laboratory is strongly
preferred. This test should be performed in conjunction with the multiview abdominal X-ray since the X-
rays better assess stent graft integrity. Other adjunctive tests may include spiral CT (without contrast in
case of impaired renal function) to aid assessment of stent graft fixation, deformation, apposition to the
vessel wall at proximal and distal fixation sites, stent graft migration, and size of the AAA with diameter
and volume measurements.
Imaging Test (Year 1)
Spiral CT with contrast 1
Abdominal X-rays
Duplex Color Doppler Ultrasound or MRA
1
Spiral CT evaluation may include "three phase technique," volume studies, 3-D reconstruction or com-
puter-aided measurements.
2
Duplex or MRA may be used in patients with renal failure or contrast intolerance.
9.9.7. Supplemental Imaging Recommendations
Note: Additional radiological imaging may be necessary to further evaluate the stent graft in situ based
on findings revealed by one of the surveillance programs. The following recommendations may be
considered:
•
If there is evidence of poor position of the stent graft, severe angulation, kinking or migration of
the stent graft on abdominal X-rays, a spiral CT, and/or CDUS should be performed to assess
aneurysm size and the presence or absence of an endoleak.
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Table 7. Imaging Recommendations
30 Day Follow 6 Month Follow
Up
X
X
X
2
12 Month Fol-
Up low Up
X X
X X
X X
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