4.4 Device Selection
• The minimum required amount of overlap between devices is three stents.
Less than a three-stent overlap may result in endoleak (with or without
component separation). However, no part of the distal component should
overlap the proximal seal stent of the proximal component, and no part of
the proximal component should overlap the distal seal stent of the distal
component, as doing so may cause malapposition to the vessel wall. Device
lengths should be selected accordingly.
• Strict adherence to the Zenith Alpha Thoracic Endovascular Graft IFU sizing
guide is strongly recommend ed when selecting the appropriate device size
(Tables 1 and 2). Appropriate device oversizing has been incorporated into
the IFU sizing guide. Sizing outside of this range can result in endoleak,
fracture, migration, device infolding, or compression.
4.5 Implant Procedure
• Systemic anticoagulation should be used during the implantation
procedure based on hospital- and physician-preferred protocol. If heparin is
contraindicated, an alternative anticoagulant should be used.
• Minimize handling of the constrained endoprosthesis during preparation
and insertion to decrease the risk of endoprosthesis contamination and
infection.
• To activate the hydrophilic coating on the outside of the Flexor introducer
sheath, the surface must be wiped with sterile gauze pads soaked in saline
solution. Always keep the sheath hydrated for optimal performance.
• Maintain wire guide position during introduction system insertion.
• Do not bend or kink the introduction system. Doing so may cause damage
to the introduction system and the Zenith Alpha Thoracic Endovascular
Graft.
• Fluoroscopy should be used during introduction and deployment to confirm
proper operation of the introduction system components, proper placement
of the graft, and desired procedural outcome.
• The use of the Zenith Alpha Thoracic Endovascular Graft requires
administration of intravascular contrast. Patients with pre-existing renal
insufficiency may have an increased risk of renal failure postoperatively.
Care should be taken to limit the amount of contrast media used during the
procedure, and to observe preventative methods of treatment to decrease
renal compromise (e.g. adequate hydration).
• To avoid twisting the endovascular graft, never rotate the introduction
system during the procedure. Allow the device to conform naturally to the
curves and tortuosity of the vessels.
• As the sheath and/or wire guide is withdrawn, anatomy and graft position
may change. Constantly monitor graft position and perform angiography to
check position as necessary.
• Inaccurate placement and/or incomplete sealing of the Zenith Alpha
Thoracic Endovascular Graft within the vessel may result in increased risk
of endoleak, migration, or inadvertent occlusion of the left subclavian, left
common carotid, and/or celiac arteries.
• Inadequate fixation of the Zenith Alpha Thoracic Endovascular Graft may
result in increased risk of migration of the stent graft. Incorrect deployment
or migration of the endoprosthesis may require surgical intervention.
• Inadvertent partial deployment or migration of the endoprosthesis may
require surgical removal.
• Landing the proximal and distal ends of the device in parallel aortic neck
segments without acute angulation (>45°) or circumferential thrombus/
calcification is important to ensure fixation and seal.
• Landing the proximal or distal ends of the device in an aortic neck segment
with a diameter that differs from that to which the graft was sized initially
may potentially result in inadequate sizing (<10% or >25%) and therefore
migration, endoleak, aneurysm or ulcer growth, or increased risk of
thrombosis.
• The Zenith Alpha Thoracic Endovascular Graft incorporates an uncovered
proximal stent, covered proximal stent (on the proximal component) with
fixation barbs, and an uncovered distal stent (on the distal component) with
fixation barbs. Exercise extreme caution when manipulating interventional
and angiographic devices in the region of the uncovered proximal stent and
uncovered distal stent.
• Do not continue advancing the wire guide or any portion of the introduction
system if resistance is felt. Stop and assess the cause of resistance; vessel,
catheter, or graft damage may occur. Exercise particular care in areas of
stenosis, intravascular thrombosis, or calcified or tortuous vessels.
• Unless medically indicated, do not deploy the Zenith Alpha Thoracic
Endovascular Graft in a location that will occlude arteries necessary to
supply blood flow to organs or extremities. Do not cover significant arch or
mesenteric arteries (exception may be the left subclavian artery) with the
endoprosthesis. Vessel occlusion may occur. If a left subclavian artery is to be
covered with the device, the clinician should be aware of the possibility of
compromise to cerebral and upper limb circulation and collateral circulation
to the spinal cord.
• Use caution during manipulation of catheters, wires and sheaths within an
aneurysm or the region of an ulcer. Significant disturbances may dislodge
fragments of thrombus or plaque, which can cause distal or cerebral
embolization, or cause rupture of the aneurysm.
• Avoid damaging the graft or disturbing graft positioning after placement
in the event reinstrumentation (secondary intervention) of the graft is
necessary.
• Care should be taken not to advance the sheath while the stent graft is
still within it. Advancing the sheath at this stage may cause the barbs to
perforate the introducer sheath.
• Do not attempt to re-sheath the graft after partial or complete deployment.
• Repositioning the stent graft distally after partial deployment of the covered
proximal stent may result in damage to the stent graft and/or vessel injury.
• During sheath withdrawal, the uncovered proximal stent and covered
proximal stent with barbs are in contact with the vessel wall. At this stage it
may be possible to advance the device, but retraction may cause aortic wall
damage.
• To avoid entangling any catheters left in situ, rotate the introduction system
during withdrawal.
4.6 Molding Balloon Use — Optional
• Confirm complete deflation of balloon prior to repositioning.
• Do not inflate balloon in the aorta outside of the graft, as doing so may
cause damage to the aorta. Use the molding balloon in accordance with its
labeling.
• For added hemostasis, the Captor Hemostatic Valve can be loosened or
tightened to accomodate the insertion and subsequent withdrawal of a
molding balloon.
• Use care when inflating the balloon within the graft in the presence of
calcification, as excessive inflation may cause damage to the aorta.
16
4.7 MRI Information
Nonclinical testing has demonstrated that the Zenith Alpha Thoracic
Endovascular Graft is MR Conditional. A patient with this endovascular graft can
be scanned safely after placement under the following conditions.
• Static magnetic field of 1.5 or 3.0 Tesla.
• Spatial magnetic gradient of 1600 Gauss/cm or less.
• The product of the spatial gradient and static magnetic field should not
exceed 48.0 T
/m.
2
• 1.5 and 3.0 Tesla Systems: Maximum whole-body-averaged specific
absorption rate (SAR) of 2 W/kg (Normal Operating Mode) for 15 minutes of
scanning (i.e., per scanning sequence).
Static Magnetic Field
The static magnetic field under consideration is the static magnetic field
pertinent to the patient (i.e., outside of scanner covering, accessible to a patient
or individual).
MRI-Related Heating
1.5 Tesla Temperature Rise
In nonclinical testing, the Zenith Alpha Thoracic Endovascular Graft produced a
maximum temperature rise of 1.7°C during 15 minutes of MR imaging (i.e., for
one scanning sequence) performed in a MR 1.5 Tesla System (Siemens Medical
Solutions, Malvern, PA, Software Numaris/4) at an MR system reported whole-
body-averaged SAR of 2.9 W/kg (associated with a calorimetry measured whole-
body-averaged value of 2.1 W/kg).
Scaling of the SAR and observed heating indicates that a SAR of 2 W/kg would
be expected to yield a localized temperature rise of 1.2°C.
3.0 Tesla Temperature Rise
In nonclinical testing, the Zenith Alpha Thoracic Endovascular Graft produced
a maximum temperature rise of 2.1°C during 15 minutes of MR imaging (i.e.,
for one scanning sequence) performed in a MR 3.0 Tesla System (GE Electric
Healthcare, Milwaukee, WI, Software 14X.M5) at an MR system reported whole-
body-averaged SAR of 2.9 W/kg (associated with a calorimetry measured whole-
body-averaged value of 2.7 W/kg).
Scaling of the SAR and observed heating indicates that a SAR of 2 W/kg would
be expected to yield a localized temperature rise of 1.4°C.
Image Artifact
MR image quality may be compromised if the area of interest is within the
lumen or within approximately 5 mm of the position of the Zenith Alpha
Thoracic Endovascular Graft, as found during nonclinical testing using the
sequences: T1-weighted, spin echo and gradient echo pulse in a 3.0 Tesla
MR system (Excite, General Electric Healthcare, Milwaukee, WI). Therefore,
optimization of MR imaging parameters to compensate for the presence of this
device may be necessary.
For US Patients Only
Cook recommends that the patient register the MR conditions disclosed in
this IFU with the MedicAlert Foundation. The MedicAlert Foundation can be
contacted in the following manners:
Mail:
MedicAlert Foundation International
2323 Colorado Avenue
Turlock, CA 95382
Phone:
888-633-4298 (toll free)
209-668-3333 from outside the US
Fax:
209-669-2450
Web:
www.medicalert.org
5 POTENTIAL ADVERSE EVENTS
Adverse events that may occur and/or require intervention include, but are not
limited to:
• Amputation
• Anesthetic complications and subsequent attendant problems (e.g.,
aspiration)
• Aneurysm enlargement
• Aneurysm rupture and death
• Aortic damage, including perforation, dissection, bleeding, rupture and
death
• Aortic valve damage
• Aorto-bronchial fistula
• Aorto-esophageal fistula
• Arterial or venous thrombosis and/or pseudoaneurysm
• Arteriovenous fistula
• Bleeding, hematoma, or coagulopathy
• Bowel complications (e.g., ileus, transient ischemia, infarction, necrosis)
• Cardiac complications and subsequent attendant problems (e.g., arrhythmia,
tamponade, myocardial infarction, congestive heart failure, hypotension,
hypertension)
• Claudication (e.g., buttock, lower limb)
• Death
• Edema
• Embolization (micro and macro) with transient or permanent ischemia or
infarction
• Endoleak
• Endoprosthesis: improper component placement; incomplete component
deployment; component migration and/or separation; suture break;
occlusion; infection; stent fracture; graft material wear; dilatation; erosion;
puncture; perigraft flow; barb separation and corrosion
• Femoral neuropathy
• Fever and localized inflammation
• Genitourinary complications and subsequent attendant problems (e.g.,
ischemia, erosion, fistula, urinary incontinence, hematuria, infection)
• Hepatic failure
• Impotence
• Infection of the aneurysm, device or access site, including abscess formation,
transient fever and pain
• Lymphatic complications and subsequent attendant problems (e.g., lymph
fistula, lymphocele)
• Local or systemic neurologic complications and subsequent attendant
problems (e.g., stroke, transient ischemic attack, paraplegia, paraparesis/
spinal cord shock, paralysis)
• Occlusion of coronary arteries
• Pulmonary embolism
I-ALPHA-TAA-1306-436-01