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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3823_Библиотеки_им_академика_М_И_Перельмана
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Renal evaluation: Renal failure is common following
TEVAR, and is associated with postoperative nonrenal
complications. Additionally, preoperative chronic renal
insufficiency is a strong risk factor for postoperative
morbidity and mortality. All patients should undergo
careful evaluation of renal function, with renal artery
duplex ultrasound if warranted. If severe renal artery
occlusive disease is present, preoperative or
intraoperative revascularization may be considered.
Preoperative intravenous hydration should be strongly
considered in high‐risk patients.
Imaging: CTA including the aortic arch, chest, abdomen,
and pelvis should be obtained. Three‐dimensional
reconstructions help visualize tortuosity of the vessels.
Particular attention should be paid to arch anatomy as
well as the positioning of the vertebral arteries if there is
involvement of zones 0, 1, or 2. If the patient is at higher
risk for spinal cord ischemia, assessment of pelvic
perfusion is imperative.
Positioning and Intraoperative
Monitoring Needs
General anesthesia with endotracheal intubation is
recommended; however, it can be done under sedation
or with local in cases where general anesthesia may not
be tolerated. Cardiac anesthesia team strongly
recommended, as they can perform intraoperative ECHO
to confirm no proximal extension of dissection.
Arterial line is strongly recommended for intraoperative
blood pressure monitoring and as an added caveat, its
tracing can estimate the degree of malperfusion of the
left arm if the left subclavian needs to be covered. Spinal
drain based on extent of coverage and if elective in order
to decrease the incidence of spinal cord ischemia as
coverage of the subclavian, intercostals, and/or spinal
artery may occur based on anatomic needs of the case.
Temperature Probe foley to ensure both appropriate
urine production intraoperative and post op as well as to
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monitor intraoperative temperature so as to avoid
hypothermia and coagulopathy.
Patient is positioned supine on an angiography table. If
using a Stille bed, ensure that the T of the bed is at the
patient’s feet rather than at the head so as to visualize the
entire aorta. In a standard TEVAR case, a standard prep
may involve preparing both groins and proximal thighs
as well as the abdomen from the umbilicus down in case
more proximal or distal control must be obtained.
If access vessels are too small, an iliac conduit may be
required:
a. Procedure in which a low abdominal wall incision is
created to gain access to the common, internal, and
external iliac arteries.
b. Depending on durability of vessels, a graft is
anastomosed in an end‐to‐side or end‐to‐end
configuration.
c. An incision is made on the graft and a long 8 Fr
sheath can be introduced and secured with umbilical
tape.
d. The remainder of the endograft deployment is the
same as a standard TEVAR which is described
below.
e. At the end of the case, the graft is dealt with in one
of several ways:
1. Tying off the graft as a stump.
2. Sewing the distal end of the conduit to more
distal segment of iliac as an interposition graft.
3. Passing the graft under the inguinal ligament
and performing end‐to‐side anastomosis to the
common femoral artery (ideal if future
cannulation is anticipated).
If subclavian coverage is planned in an elective case and
subclavian revascularization is required, the head should
be turned toward the right and the neck and clavicular
region should be prepped into the field. If
thoracoabdominal aneurysm case then depending on the
extent of arch disease, the chest, bilateral neck,
abdomen, and left arm should be prepped into the field.
Procedural Steps
Deployment of specific grafts varies from product to
product. Below is a brief general guide for a standard
TEVAR:
Step 1. Ultrasound guided bilateral access initially
with 5–7 Fr on the contralateral side and 7 Fr on the
working side.
Step 2. Confirm access wire in each femoral artery
using fluoroscopy.
Access should be in the top half/top third of the
femoral head to make manual pressure easier.
Confirmatory shot can be anterior or slightly
anterior oblique (Figure 4.7).
Step 3. A guidewire and angled catheter are used to
enter the abdominal aorta and under fluoroscopy
the wire and catheter are guided into the thoracic
aorta. A wire exchange for a stiff wire should be
performed at this time with the angled catheter in
place. As with all catheter, sheath, and wire
exchanges described here and in other chapters, it is
critical to perform appropriate over wire and
through catheter exchanges for all of your
equipment so as to keep the equipment in the
appropriate position and to avoid further damage to
the aortic wall.
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Figure 4.7 Confirmation of common femoral
cannulation.
Step 4. Confirmation of wire in true lumen with
intravascular ultrasound (IVUS) (optional but
recommended for dissections) (Figure 4.8).
Step 5. Perclose on operative side if this is done
completely percutaneously, usual recommendation
is for deployment of two devices at 10 o’clock and 2
o’clock positions.
Step 6. Advancement of marked diagnostic catheter
(usually a pigtail or contra catheter depending on
supplies at facility) to shoot diagnostic aortogram on
contralateral side (Figure 4.9).
This step is critical as this is the last time possible
for accurate sizing of the aortic lumen diameter as
well as length from the subclavian artery, entry
tear, and distal landing zone. IVUS can be used in
this step as well to further confirm size and
proximal extent of dissection. It is generally
recommended to oversize the stent‐graft about 5–
10%. Ventilation should be held during any
diagnostic shots for appropriate sizing.
Step 7. Exchange introducer sheath for device
sheath on working side.
Step 8. Advance over wire into thoracic aorta and
confirm placement prior to deployment.
Step 9. Deploy graft:
Figure 4.8 Intravascular ultrasound displaying
true and false lumen (probe in compressed true
lumen).
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Figure 4.9 Arch aortogram to identify seal zone.
If intubated and mechanically ventilated, the
respirations should be held for accurate placement.
Systolic blood pressure during this step should be
maintained at 100 mmHg so as to avoid graft
motion during deployment. All of the endografts
listed above are self‐expanding, and balloon
molding is neither needed nor is it generally
recommended as this may further damage an
already vulnerable aortic wall.
Step 10. Completion shots (Figure 4.10):
After deployment, this is the most important step
as adequacy of repair and prevention of further
aortic degeneration requires correction of
endoleaks. This step is also critical to ensure that
the graft did not move during placement and that
there is appropriate filling of the subclavian
(assuming it was not intentionally covered), distal
thoracic aorta, and the abdominal aorta and runoff.
If dissection extends into visceral aorta, consider
using dissection stent to promote aortic modeling.
Step 11. If any type 1 or type 3 endoleaks are
present, extend proximally and distally or provide
more overlap as seen fit to correct them or use a
large diameter balloon to better seal the graft to the
aortic wall proximally or distally (Figure 4.11).
Step 12. Remove device and deploy the previously
placed perclose devices on the large sheath side.
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Figure 4.10 (a)–(d) Measurement of coverage
length and completion angiogram.
Figure 4.11 (a)–(c) Treatment of penetrating aortic
ulcer, initial endoleak, and complete resolution with
distal balloon insufflation.
Step 13. Manual pressure or percutaneous closure
device on the contralateral side.
If manual pressure is applied, then a general rule of
thumb is to hold 5 minutes of pressure for each Fr
size (i.e. 6 Fr sheath gets 30 minutes of pressure).
Step 14. Check distal pulses to confirm no distal
embolization.
Postoperative Course/Surveillance
Monitored Setting
In elective surgery admit TEVAR cases that do not
require spinal drain or IV drip, anti‐impulse control a
surgical step down unit or telemetry unit may be
sufficient. In acute settings such as trauma, rupture, or
acute dissection, postoperative monitoring should occur
in an ICU setting as these patients will likely have
comorbid injuries, an arterial line, a spinal drain, and/or
require IV drip blood pressure medications.
Spinal Drain
For any nonemergent cases requiring coverage of >20
cm of aortic length, anticipated coverage of T8 or lower,
coverage of the subclavian, or prior abdominal aortic
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stent‐graft placement, a spinal drain is recommended to
decrease the incidence of spinal cord ischemia and its
neurologic sequelae. In order to drive the hydrostatic
pressure to be high enough for adequate spinal cord
perfusion, two criteria are to be met: (i) systolic blood
pressure >100 mmHg (without approaching
hypertension that could further damage the aortic wall)
and (ii) intrathecal pressure <10 mmHg. Generally
speaking, a spinal drain is kept clamped at 10 mmHg and
every hour 10 cc or so of fluid is allowed to drain. If the
patient develops headaches or lower extremity
symptoms, the drain is opened and allowed to drain until
symptoms resolve. Spinal drains should be removed
within 24–72 hours of placement. It is important to note
that, if the patient was on anticoagulation for any reason,
it should be held for the appropriate half‐life clearance so
as to avoid any bleeding complications.
Blood Pressure Control
As stated above when discussing spinal drains, blood
pressure control is paramount in the perioperative
period as well as in the patient’s eventual lifelong
postoperative course. In the preoperative course, blood
pressure goals for patients with dissection disease are
generally recommended to be in the normotensive range.
If the patient does not have signs of malperfusion and
symptoms are absent with adequate blood pressure
management, it may be acceptable to follow these
patients clinically without placement of stent‐graft.
Symptomatic dissections despite adequate blood
pressure control or dissections with signs of
malperfusion (mesenteric ischemia, renal ischemia,
ischemic hepatopathy, or lower extremity ischemia)
require immediate treatment. In patients with ruptured
thoracic aorta, blood pressure resuscitative goals are to
make sure that the patient is adequately perfusing the
brain and vital organs in anticipation of emergent
surgical repair. Blood pressure goals for patients with
traumatic aortic injury are similar to those of
spontaneous dissection, excluding patients with
transected aortas.
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