SURGICAL MANAGEMENT of thoracic abdominal aortic aneurysms.pptx

SURGICAL MANAGEMENT OF
THORACOABDOMINAL
AORTIC ANEURYSMS

INTRODUCTION
- Surgical repair of DTAA and TAAA is a major challenge in vascular surgery.
- The surgery requires reattaching multiple arteries to a synthetic graft or aortic homograft.
- The surgery poses significant risks of stroke, renal failure, cardiac or pulmonary
complications, and paraplegia leading to disability or death.

Dr. Ernest Stanley Crawford
Lifetime Experience Of Over 1500 TAAA, Achieving An Overall Mortality Of 8% And Paralysis Risk Of 16%, Crawford Set The Standard For A
Generation Of Surgeons

PATHOLOGY
It is important, for the surgeon to understand the pathology involved in
an individual patient because it can affect technical considerations in
thoracoabdominal aneurysm repair.

Degenerative aneurysms / “inflammatory aneurysms”
• Degenerative aneurysms are the most common TAAA.
• They occur in older patients with atherosclerosis and a smoking history.
• They are associated with inflammation and collagen remodeling of the aorta.
• Treatment is difficult due to calcification, damaged intimal surface, and comorbidities.

Inheritable
• Genetic mutations can weaken the aortic wall and lead to aneurysms and dissections.
• Familial aneurysms and noncategorized patients can also be predisposed to aneurysms and aortic dissection
due to similar mutations.
• Patients with Ehlers-Danlos and Loeys-Dietz syndromes have more fragile aortas than those with Marfan
syndrome, requiring different surgical techniques.
• In some severe cases, surgical repair may not be a viable option..

Trauma, Mycotic, Vasculitis
• In cases of severe trauma or mycotic aortitis, radical aortic and periaortic debridement may be necessary.
• For thoracoabdominal aneurysms associated with certain diseases, repair may be complicated by branch
vessel occlusive disease and involvement of the heart and lungs.

ANATOMIC CLASSIFICATION
• Thoracoabdominal aortic aneurysms are classified by extent of aortic involvement.
• Crawford type 2 has the greatest paralysis risk followed by types 1, 3, 4.
• Thoracic aortic aneurysms confined to the distal arch and descending thoracic aorta have the lowest paralysis
risk from surgery.

CLASSIFICATION OF THORACOABDOMINAL AORTIC ANEURYSMS

• Natural rate of growth of aorta is very slow
0.07 cm per yr – Asc. Aorta
0.19 cm per yr – DTA
• As the aorta grows to aneurysmal proportions the growth rate become faster
• A dissected aorta grows even faster
0.14 cm per yr – Asc. Aorta
0.28 cm per yr - DTA

INDICATIONS FOR SURGICAL
TREATMENT
• The primary indication for treatment of aortic aneurysms is rupture risk, which is generally considered to correlate with
aortic diameter in accordance with Laplace’s law.
• The natural history of thoracic aneurysms indicates that diameter, age, chronic obstructive pulmonary disease (COPD) or
renal insufficiency, extent, and expansion rate are independent risk factors for rupture.
• The decision to treat a TAAA is complex and depends on factors such as natural history, surgical risk, and individual patient
characteristics. Other indications may also lead to treatment of smaller TAAAs.
• Most aortic surgeons put the threshold for risk/ benefit at about 6 cm from natural history information weighed against
surgical risk and long-term survival

Indications for Operation
• In asymptomatic patients,
– the decision to consider surgical repair is based primarily on the
diameter of the aneurysm.
– Elective operation is recommended when diameter exceeds 5 to 6 cm
– Or when the rate of dilatation exceeds 1 cm per year
– To prevent fatal rupture
▪ Degenerative DTAAs and TAAAs with superimposed acute dissection
▪ Malperfusion caused by chronic dissection
▪ With connective tissue
-The threshold for operation is lower
▪ The onset of new pain
• often heralds significant expansion, leakage, or impending rupture.

Nonoperative management
• Strict blood pressure control
• Rate control
• Cessation of smoking
• Surveillance /Follow up
for asymptomatic patients who have small
aneurysms.

PATIENT EVALUATION
• The decision to treat must begin with a definitive evaluation of cardiac, pulmonary, renal, and overall vitality
factors to establish the patient's fitness for elective surgery.
• This evaluation is crucial when discussing operative risk, despite being expensive and time-consuming for
patients and families.

PREOPERATIVE EVALUATION
• CARDIAC- ECHO/CART/CTA
• PULMONARY- PFT
• RENAL- USG/DOPPLER/RFT

Imaging
• MRI and CTA are important for aortic and branch vessel imaging.
• Identifying patent intercostal arteries is important.
• Detailed understanding of complex dissection anatomy is necessary.
• Plaque morphology should be considered in preoperative planning.
Four-dimensional magnetic resonance angiography allows for noninvasive measurement of flow dynamics and
anatomy, providing clinical understanding of treatment effects and complex flow dynamics in aneurysms and
aortic dissection.

Informed Consent
• Informed consent for high risk surgeries should include both best and worst case scenarios for the patient to
make a decision consistent with their goals.
• The consent conversation for surgeries with risks of paraplegia, stroke, renal failure, and ventilator
dependence should be a realistic discussion of probability and uncertainty.
• Surgeons and patients should be more selective about treatment for older patients.

SURGICAL REPAIR
• That plan will depend on anatomy and pathology that can vary greatly
between patients, requiring the surgeon and anesthesiologist to
adapt.
• Surgeons may favor different surgical approaches ranging from simple
cross-clamp (Crawford technique) with adjunctive measures to
protect the kidneys and spinal cord, assisted circulation-AC (atrial–
femoral or femoral–femoral bypass), or hypothermic circulatory arrest
(HCA).

Extracorporeal Circulation
• AC usually atrial–femoral (partial heart bypass) is a partial heart bypass technique that allows for adjustable
perfusion pressures during proximal repair without requiring full systemic heparinization.
• HCA involves complete cardiopulmonary bypass with arterial and venous cannulas, cooling to 16-18°C, and
cerebral perfusion during aortic reconstruction, but is the least commonly used technique due to complexity
and risk of bleeding.

Left heart bypass is the most commonly used technique of
assisted circulation and is dependent on the lungs for
oxygenation and the heart as the primary pump. The circuit is
from the left atrium via direct cannulation or through the
pulmonary vein to a centrifugal pump back into the arterial
circulation (most commonly the femoral artery).
Extracorporeal Circulation

Other Perfusion Techniques
• Distal aortic perfusion and selective perfusion of the mesenteric
arteries can be achieved without pump devices. The Gott shunt and
external axillofemoral artery bypass have been used as a passive
bypass circuit for repair of DTAA and TAAA.
• Cambria describes an in-line mesenteric shunt technique which can
restore pulsatile flow to the mesenteric circulation within 25 minutes.

• The anesthesiologist is as important as the surgeon in the success of
these complicated aortic reconstructions.
ANESTHESIA CONSIDERATIONS

ANESTHESIA
The anesthesia for TAAA repair is complex, requiring multisystem
monitoring and control.
Arterial lines in the upper (radial artery) and lower
(femoral artery) extremities, pulmonary artery
catheter for monitoring cardiodynamics (cardiac
index, central venous pressure, pulmonary artery
pressures),
and transesophageal echo to evaluate ventricular
function and valve function are used to optimize
mean arterial pressure and cardiac function.

• Cranial and peripheral
electrodes are placed for
monitoring of somatosensory
or motor evoked potentials to
assess intraoperative spinal
cord protection and perfusion.
• Electroencephalogram (EEG)
monitors central nervous
system activity because
barbiturates are used to reduce
oxygen demand prior to and
during aortic occlusion.

• A 16-Fr Medtronic lumbar spinal
drain is fluoroscopically placed in
most patients to monitor and
control spinal fluid pressure by
draining spinal fluid to improve
spinal cord blood flow during aortic
occlusion.

• When one lung ventilation is
required in extensive proximal aortic
replacement, we use an Arndt
endobronchial blocker,
bronchoscopically placed using a
guide wire, which we think is easier
and safer than a double lumen
endotracheal tube. This technique
provides excellent lung isolation
without the need to change
endotracheal tubes at the end of
surgery.

• Blood and nasopharyngeal temperature are monitored because these correlate
with spinal fluid and brain temperature.
• Coagulation parameters, blood chemistries and arterial blood gases are closely
monitored throughout surgery.
• The anesthesiologist uses vasoactive medications to control arterial pressure and
maximize cardiac function.
• As for blood pressure maintenance, mean proximal pressure should be maintained
around 80–100 mmHg and pressure distal to the clamp to be 60–80 mmHg
• Infusing sodium bicarbonate (0.05 mEq/kg/min) while the aorta is occluded
above the renal arteries prevents systemic acidemia.
• Our group administers methylprednisolone after induction and naloxone (1
μg/kg/hour) is infused during and after the procedure.
• Mannitol is given before and during aortic occlusion and after renal reperfusion.

• Moderate systemic hypothermia (31–34°C) is used to prolong spinal cord and organ
ischemic tolerance.
• Aggressive blood component replacement is important to prevent coagulopathy.
• During the surgical exposure the anesthesiologist cools the patient (34°C or lower) with a
cold operating room and intravenous (IV) fluids.
• As the time for aortic clamping approaches, our anesthesiologists drain enough spinal
fluid to achieve a spinal fluid pressure (SFP) less than 6 mm Hg during aortic occlusion.
• If assisted circulation (cardiopulmonary bypass, circulatory arrest or atrial femoral
bypass) is used we complete the exposure dissection before cannulation and
heparinization to minimize bleeding.
• During surgical reconstruction, the anesthesiologist assures that the patient is volume
resuscitated with blood reclaimed from the high speed cell saver, red blood cells and
fresh frozen plasma to replace coagulation factors from blood loss.

ANESTHESIA
• Induction; Double Lumen Endotracheal tube / Ardnt’s Endobronchail blocker.
• Lines – Central Venous Access; PA Catheter; Arterial Lines in Upper and Lower Limbs.
• Foley’s Catheter.
• ABG and Electrolyte Monitoring.
• CSF Drains 10 mmHg or less.
• Cranial and Peripheral Electrodes.
• PreOP Antibiotics.
• Prevent Acidosis.

SPINAL CORD PROTECTION
• Major focus.
• Risk Factors for Spinal Cord Ischaemia :
• Aneurysm Extent
• Open Repair.
• Prior Aortic Operations.
• Perioperative Hypotension.
• Early detection enables immediate treatment.
• Maintain spinal cord perfusion by
• Augmenting arterial blood pressure and augmenting cardiac output,
• Prevent hypotension
• Reducing CSF pressure, and
• Reducing central venous pressure.

• Mild permissive hypothermia (32– 34 °C) is employed.
• Routine CSF drainage and left heart bypass.
• Sequential aortic clamping.
• Reattachment of patent segmental intercostal and lumbar arteries
between T8 and L1.
• Mean proximal pressure around 80–100 mmHg and pressure distal to
the clamp 60–80 mmHg.
• Rewarming after reperfusion can be accomplished with warmed
saline and forced air warming blanket.

OPERATION
• Operative strategies and techniques vary considerably depending
upon the extent and characteristics of the aneurysm.

Preparation and exposure
• Patient Positioning : Right lateral
decubitus with the shoulders at 60
degrees and the hips at 30 degrees.
• The left arm is placed on an armrest.
• Pressure points are padded with foam.
• A shoulder roll is placed under the
chest so that the right shoulder is free
from pressure.
• The operating table is hyperextended to
open the space between iliac crest and
costal margin.
• Draping allows access to the entire left
chest, abdomen, and both groins.

incision
• The level of the incision is based upon
the proximal extent of the aneurysm in
the thoracic aorta.
• A curvilinear thoracoabdominal incision
is made from just posterior to the
inferior aspect of the left scapula,
curving along the 7th rib and across the
costal margin toward a point about 3–4
cm to the left of the umbilicus.
• When a repair involves the iliac arteries,
the incision may be extended inferiorly
around the umbilicus and into the
midline to just above the pubic
symphysis.

Preparation and exposure
Aneurysms beginning near the diaphragm (extent IV) are exposed through the eighth interspace, while
those extending more proximally (extents I, II, III and V) are usually approached through the sixth
interspace. Proximal exposure may require division or resection of the sixth rib. The fifth space may be
appropriate when improved exposure of the distal arch and left subclavian is required.

• Prior to entering the chest, the left lung
is deflated and single lung ventilation is
initiated.
• Care must be taken not to injure the left
phrenic nerve when the costal margin
and diaphragm are divided.
• The diaphragm is divided in a
circumferential fashion to protect the
phrenic nerve.
• A 2–3 cm cuff of diaphragmatic tissue is
left on the chest wall, preserving the
bulk of central musculature and
allowing secure closure upon
completion of the procedure.

Contd surgical exposure
• If the patient has had previous aortic or thoracic surgery, the exposure can
be more difficult because of periaortic scarring, inflammation and
adhesions.
• Dissect and expose the celiac, superior mesenteric, and left renal arteries.
• Occasionally the left renal vein is retro-aortic, requiring the surgeon to
divide it for re-anastomosis after aneurysm repair.
• The extent of exposure of the arch vessels depends on where the proximal
aortic clamp is placed and requires avoidance of injury to the phrenic and
the vagus nerve and its recurrent branch because injury to these nerves
increases the risk of pulmonary complications.
• Patients should be informed preoperatively about recurrent nerve injury
and the resulting vocal cord dysfunction, which cannot always be avoided
and occurs

PROXIMAL DISSECTION
• Prior to clamping, divide remnant of ductus. Mobilize distal
aortic arch.
• Dissect circumferentially, separate esophagus and pulmonary
artery.
• Protect left vagus and recurrent laryngeal.
• Vagus can be sacrificed after RLN takeoff.
• Heparin is administered intravenously for left
heart/cardiopulmonary bypass once the exposure is
complete.

Other Perfusion Techniques
• Distal aortic perfusion and selective perfusion of the mesenteric
arteries can be achieved without pump devices. The Gott shunt
and external axillofemoral artery bypass have been used as a
passive bypass circuit for repair of DTAA and TAAA.
• Cambria describes an in-line mesenteric shunt technique which
can restore pulsatile flow to the mesenteric circulation within 25
minutes.

Sequential clamping strategy
Following institution of left heart bypass, the proximal portion of the
aneurysm is isolated by placing clamps distal to the left subclavian
artery and across the upper/mid-descending thoracic aorta

extent II thoracoabdominal aortic aneurysm repair using a
multibranched graft.
A typical patient undergoing such a repair will have an aneurysm extending from the left subclavian artery down
to the aortic bifurcation.

The chest is entered through the sixth intercostal space. Left medial visceral rotation and circumferential division of
the diaphragm enable exposure of the entire thoracoabdominal aorta. The use of table-mounted self-retaining
retractors maintains stable exposure throughout the procedure.

Left heart bypass (LHB) is initiated by placing a cannula in the left atrium via a left inferior pulmonary venotomy and then
connecting it to the drainage line of the LHB circuit. After LHB flow is initiated, the proximal aortic clamp is placed just distal to
the left subclavian artery, and the distal aortic clamp is applied across the mid-descending thoracic aorta. The aortic segment
between the two clamps is opened longitudinally by using electrocautery.

After back-bleeding intercostal arteries are ligated, the aorta is transected 2 to 3 cm distal to the aortic clamp and separated
from the underlying esophagus. A four-branched aortic graft is tailored by stretching the graft so that it is taut, lining up the
origin of the celiac graft with the origin of the left renal artery, and cutting the proximal end of the aortic graft at the point
where it reaches the proximal anastomosis site.

After the proximal anastomosis is completed, LHB is stopped. The aorta is opened longitudinally down to the aortic bifurcation.
The celiac and superior mesenteric arteries are cannulated with the balloon perfusion catheters, and selective perfusion is
initiated. The renal arteries are similarly cannulated with balloon perfusion catheters to enable intermittent perfusion with cold
crystalloid solution.

The aortic cross-clamp is moved down to the aortic graft distal to the intercostal patch. After the graft is trimmed, the
distal anastomosis is performed

The visceral arteries are anastomosed.

The completed repair is shown.

Sequential clamping strategy
• In a proximal aneurysm, clamp between the left common carotid and left subclavian arteries.
• Left heart bypass flow is increased toward a target between 1.5 and 2.5 L / min.
• Aorta transected 2 cm distal to the proximal clamp and separated from the esophagus.
• A properly sized gelatin-impregnated woven Dacron graft with 4 side branches is selected.
• Graft Orientation, as graft shifts when the viscera are rotated back to the anatomic position.
• The proximal anastomosis is carried out using running 3-0 polypropylene suture.
• For fragile aortic tissue (Marfan syndrome) 4-0 polypropylene suture is utilized.
• Teflon strips to reinforce.

Distal anastomosis and viscera/renal vessel
attachment
• Before starting left heart bypass, selective visceral perfusion catheters
are prepared for use.
• The size of the catheters varies between (6Fr–13Fr).
• These are attached to a line off of the arterial return tubing allowing
continued delivery of oxygenated blood from the pump circuit to the
abdominal viscera, usually at a flow rate of 200–400 mL / min.

• The abdominal segment is clamped 2–3 cm
below the proposed distal anastomotic site.
• The remaining aorta is opened longitudinally
down to the aortic bifurcation.
• The origins of the visceral and renal arteries
are identified and endarterectomized if
necessary.
• Each visceral vessel and renal arteries are
cannulated with an appropriate size cannula.
• Brisk intercostal/ lumber artery back-
bleeding is controlled with 2-0 silk figure-
eight sutures in order to minimize blood
loss, improve visualization, and prevent
shunting of blood away from the spinal
circulation.

• After the patch reimplantation of the intercostal arteries is
completed, the proximal aortic cross-clamp is moved down the aortic
graft to a position immediately distal to the intercostal patch.
• The distal anastomosis is performed in an end-to-end configuration
with a continuous 3-0 or 4-0 polypropylene suture depending on the
aortic disease and reinforced with pledgeted 4-0 polypropylene
sutures as needed.

• The aortic graft and its four branches are filled with blood from the
distal anastomosis. Vascular clamps are placed across each branch of
the graft and the aortic cross-clamp on the main body of the graft is
slowly removed to re-establish pulsatile blood flow to the pelvis and
both lower extremities.
• At this point the patient is weaned from left heart bypass.

Visceral and renal vessels anastomosis
• The sequence of visceral/renal vessel anastomosis varies depending on the
anatomy.
• Celiac Artery - the superior 10 mm branch, located anteriorly, is trimmed
and anastomosed in an end-to-end configuration with a continuous 5-0
polypropylene suture.
• The superior mesenteric artery is anastomosed to the other 10 mm branch
in the same fashion.
• As for renal arteries, the right renal artery anastomosis is usually done first
because of its medial location. The right-sided 8 mm side branch is
trimmed to the appropriate length and anastomosed in the same fashion
with a continuous 5-0 polypropylene suture.

• As for renal arteries, the right renal
artery anastomosis is usually done
first because of its medial location.
The right-sided 8 mm side branch is
trimmed to the appropriate length
and anastomosed in the same
fashion with a continuous 5-0
polypropylene suture.
• Left renal artery origin is harvested
as a button. The remaining 8 mm
side-branch graft is trimmed to the
appropriate length and anastomosed
to the left renal artery.
• Care is taken to ensure that the
artery and the branch graft are not
kinked when the peritoneal sac is
returned to its anatomic position.

Alternatively, a visceral patch including the celiac, superior mesenteric,
and right renal arteries is fashioned and sewn to the graft. However,
this should be avoided in patients with connective tissue disorders due
to the possibility of developing visceral patch aneurysmal dilatation.

After anastomosis and closure.
• Following aortic reconstruction, heparin is reversed with protamine.
• Meticulous hemostasis at all suture lines and cannulation sites.
• Visceral, renal, and peripheral perfusion are assessed.
• The remaining aneurysm wall is wrapped around the aortic graft and
secured with a running suture.
• The diaphragm is re-approximated with #1 polypropylene suture.
• The thoracotomy is closed using heavy braided polyester suture.
Stainless steel wires or rib plating system may be used around the
costal margin if necessary.

Post operative care
• Meticulous BP control. Hypertension – disruption of suture lines.
• MAP target 80-100 mmHg.
• Marfans, Acute Dissection – Lower BP target.
• Maintain CSF pressures between 10-12 mmHg.
• Remove CSF drain in 48 hours.
• Weaning and extubation in 24 hours.
• Ambulation on POD 2-3 after CSF drain removal.

PATIENT POSITIONING
• For a thoracoabdominal incision, the patient is positioned in
a lateral decubitus position with the left side up.
• The shoulders are usually vertical at 60 degrees but the
pelvis is tilted to 30 degrees so the left femoral artery and
vein can be easily accessed for aortofemoral bypass, arterial
line, or cannulation if left heart bypass is planned.
• The left arm is placed on an armrest.
• Pressure points are padded with foam.
• A shoulder roll is placed under the chest so that the right
shoulder is free from pressure.
• The operating table is hyperextended to open the space
between iliac crest and costal margin.
• Draping allows access to the entire left chest, abdomen, and
both groins.

SURGICAL EXPOSURE
• The level of the incision is based
upon the proximal extent of the
aneurysm in the thoracic aorta.
• A curvilinear thoracoabdominal
incision is made from just posterior
to the inferior aspect of the left
scapula, curving along the 7th rib
and across the costal margin
toward a point about 3–4 cm to the
left of the umbilicus.

• When a repair involves the iliac arteries,
the incision may be extended inferiorly
around the umbilicus and into the midline
to just above the pubic symphysis.

C d
Aneurysms beginning near the diaphragm (extent IV) are exposed through the eighth interspace, while
those extending more proximally (extents I, II, III and V) are usually approached through the sixth
interspace.
Proximal exposure may require division or resection of the sixth rib. The fifth space may be appropriate
when improved exposure of the distal arch and left subclavian is required.

Image description.
• Figure 79.4 (A,B)
• The lower the interspace of the incision, the lower the risk of
pulmonary complications, so the lowest incision is chosen that allows
aortic repair.
• In older patients and in patients with elevated BMI, in addition to
cutting the costochondral junction the ribs are cut posteriorly to
create a controlled cut instead of a fracture.
• As much of the latissimus dorsi and serratus anterior is preserved as
possible by incising them lower than the interspace to be opened.

• Prior to entering the chest, the left lung is
deflated and single lung ventilation is
initiated.
• Care must be taken not to injure the left
phrenic nerve when the costal margin and
diaphragm are divided.
• The diaphragm is divided in a
circumferential fashion to protect the
phrenic nerve.
• A 2–3 cm cuff of diaphragmatic tissue is left
on the chest wall, preserving the bulk of
central musculature and allowing secure
closure upon completion of the procedure.
The diaphragmatic crus is divided. The left
renal artery is identified and exposed. The
superior

Contd surgical exposure
• If the patient has had previous aortic or thoracic surgery, the exposure can be more
difficult because of periaortic scarring, inflammation and adhesions.
• Dissect and expose the celiac, superior mesenteric, and left renal arteries but if the
aneurysm is very large or is inflammatory, the mesenteric exposure may be too difficult
and is avoided.
• In the case of associated mesenteric ischemia, the superior mesenteric artery (SMA) can
be exposed more completely if necessary by dissecting anterior to the kidney between
the peritoneal sac and Gerota’s fascia.
• Occasionally the left renal vein is retro-aortic, requiring the surgeon to work around it
and/or divide it for re-anastomosis after aneurysm repair (Fig. 79.6B). The extent of
exposure of the arch vessels depends on where the proximal aortic clamp is placed and
requires avoidance of injury to the phrenic and the vagus nerve and its recurrent branch
because injury to these nerves increases the risk of pulmonary complications. Patients
should be informed preoperatively about recurrent nerve injury and the resulting vocal
cord dysfunction, which cannot always be avoided and occurs

Figure 79.5 (A–C) After incising the diaphragm down to the peritoneal reflection, the spleen, pancreas, colon, and left
kidney are mobilized off the retroperitoneum. It is important to not dissect into the psoas fascia but open Gerota’s fascia
posteriorly closer to the midline so the retroperitoneal periaortic space can be easily seen and exposed. Occasionally
dissection is also anterior to the left kidney to gain access to more of the SMA.

Figure 79.6 (A) After mobilizing renal and visceral structures off the retroperitoneal space, the diaphragm is incised
through the aortic hiatus, the inferior pulmonary ligament is divided with cautery, and the periaortic lymph tissue is
divided exposing the thoracoabdominal aorta. (C) We usually dissect the first few centimeters of the left renal and
visceral arteries. Occasionally a retroperitoneal left renal vein is encountered (B), which we preserve by dividing
between two straight DeBakey vascular clamps and then sewing it back together after the arterial reconstruction.

DISTAL DISSECTION
• ureteral stents can be placed prior to surgery so the ureters can be
identified more easily.
• It is important to take the time to get complete enough anatomic
exposure in anticipation of problems that might develop (such as a
need for a more proximal clamp or more distal exposure) so that if
the need arises, further dissection is not necessary after aortic
occlusion.

ANEURYSM REPAIR
Initial Clamping – Anticoagulation Strategy
• With the simple cross-clamp surgical technique heparin flush (1000
units/liter) is used on the field.
• Systemic heparin is used if patients have previous aortic grafts or if
clamping is proximal to the subclavian or carotid arteries and then the
dose is small (3000–5000 units).
• In patients with AC (partial bypass), heparin requirements are
reduced and ACTs are monitored.
• With complete heart bypass (hypothermic arrest) total systemic
heparinization is required (400 units/kg).

ANEURYSM REPAIR
Initial Clamping
• Once the exposure is complete and the systolic pressure is <100 mm Hg, temperature
<34°C, SFP <6 mm Hg and barbiturate burst suppression is initiated, the aorta is cross-
clamped and the aneurysm opened for repair.
• Mean arterial pressure is kept at greater then 100 mm Hg while the aorta is clamped. If
there are many open intercostal arteries and/or assisted circulation is used, a distal or
distal sequential clamp technique is used to avoid what can be exsanguinating back-
bleeding from open intercostal and lumbar arteries.
• In aneurysms of just the descending thoracic aorta we usually do not reattach intercostal
arteries but in TAAA patients before or after opening the aneurysm, the intercostal
arteries chosen for reimplantation by preoperative MRA and/or patency and location at
surgery are temporarily occluded using micro bulldog clamps (usually 2–4 arteries
between T8 and L2) and the remaining intercostal and lumbar vessels are quickly
oversewn to minimize blood loss and maximize collateral perfusion pressure.
• Similarly, Fogarty balloon catheters are used to occlude the visceral and renal arteries. At
this point, the renal artery orifices are exposed and each

• Similarly, Fogarty balloon catheters are used to occlude the visceral
and renal arteries.
• At this point, the renal artery orifices are exposed and each kidney is
cooled with 300–400 mL of cold (4°C) renal perfusion solution (12.5 g
of mannitol and 1000 units of heparin/ liter of lactated Ringer’s)
(Video 79.2).
• This gives hypothermic renal protection and also further lowers the
body temperature to 31–32°C to enhance spinal cord and end organ
ischemic tolerance. This sudden volume infusion increases SFP, which
may require more drainage to keep the SFP low.

Proximal Anastomosis
• After completing this portion of the operation, the proximal graft aortic
anastomosis is performed using 2-0 Prolene on a large CT1 needle most of the
time.
• Depending on the tissue integrity (dissection, calcium requiring aortic
endarterectomy or just a fragile thin aortic wall), a finer suture or needle (3-0
suture or SH needle) and/or felt strips or pledgets may be used to reinforce the
anastomosis.
• An important technical point is that all anastomoses should be done so the aorta
is not repeatedly cross-clamped to repair leaks. This requires a little more time,
but makes for a faster, less traumatic anastomosis.
• After completing the proximal anastomosis, the patient is put in Trendelenburg
and the anastomotic integrity is tested by placing a vascular clamp on the graft
after flushing (to remove air and thrombus that can cause a stroke via the arch
vessels) and removing the proximal clamp. If there is a leak requiring attention,
we will usually repair this with a pledgeted stitch without reclamping the aorta.

Visceral–Renal Reattachment
• The next stage of the repair is visceral and renal artery reattachment, which is usually done with a
Carrel patch directly to the aortic graft (Fig. 79.8). The patch configuration is determined by the
spacing of the vessels and the most common configuration is the celiac, SMA and right renal in
one patch and the left renal artery attached separately (Video 79.4). Another common grouping is
the celiac and SMA in one patch and both renal arteries attached separately. The Carrel patch is
kept as narrow as possible to avoid patch aneurysms, but if the vessels are spaced too far apart
they are attached individually to avoid a large visceral patch that is prone to aneurysm dilation
over time. There is a tendency by inexperienced surgeons to sew all the visceral vessels on one
patch or create a too large proximal bevel and this more often than not leads to problems later.79
In our experience, by using the above principles for visceral patch reconstruction, we have
avoided patch aneurysms. However, individual bypass grafts to the visceral arteries is another
strategy that has been advocated with the Coselli branched graft specifically designed for this,80
especially in patients with connective tissue disorders like Marfan syndrome, because patch
aneurysms are more prevalent in patients with connective tissue disease. In about a third of
patients, an endarterectomy of some or all of the renal and visceral vessels is required (Fig. 79.9)
because of calcified plaque with or without stenosis (Video 79.3). If the renal or visceral artery
has been previously stented, the stent is usually removed with the endarterectomy plaque. Some
surgeons prefer bypass or direct stenting rather than endarterectomy because of

Figure 79.8 (A) When attaching visceral and renal arteries to
the graft it is important to keep the Carrel patch as narrow
(small) as possible so patch aneurysms do not form. Spacing
between the vessels determines patch configuration and if the
vessels are too far apart they are attached individually. (B)
Sewing a visceral patch comprising the celiac and SMA with
their balloon catheters in place. These are removed after
establishing blood flow to that portion of the aorta. (C)
Completed graft within the aneurysm sac with arrows to the
visceral patch and left renal artery.

Figure 79.9 Approximately 35% of patients require a visceral
and/or renal endarterectomy because of occlusive disease or a
very calcified aorta or vessel orifice. This is a sequence of renal
endarterectomy (A), which is attached directly to aortic graft
(B).

• possible flap dissection beyond the endarterectomy endpoint, which can
require additional exposure and artery repair to avoid occlusion. However,
the superior long-term patency of a properly endarterectomized artery is
why we prefer endarterectomy. A bypass to a renal or visceral vessel may
be necessary, however, if the endarterectomy fails or the artery is
aneurysmal or too distant from the graft surface for easy no-tension
reattachment. In patients with dissections, the dissection flap may extend
some distance into a visceral or renal artery, which can create a possible
flap occlusion with reattachment. In most cases the flap can be excised to
create a common channel for reattachment but stenting the true lumen
directly has also been proposed as an effective technique.81 After
completing the visceral and renal reattachment, the patient again is put in
the Trendelenburg position with

• flushing of the graft and then reestablishing blood flow to the visceral
and renal arteries (by removing the Fogarty occlusion balloons).
Intravenous indigo carmine is then given to document when urine is
produced after renal reperfusion. The visceral and renal flow is
evaluated with vessel palpation and a hand-held Doppler to confirm
normal blood flow. If there is a concern regarding patency,
intraoperative duplex is used to interrogate the arteries in question.
In our experience, the average time for the proximal anastomosis and
re-establishing renal blood flow is 47 minutes, but it is not unusual to
exceed one hour. If renal ischemia time is longer, the kidneys are
flushed again with the cold renal perfusion solution.

Distal Anastomosis
• After completing the visceral reattachment the aortic graft is sutured
to the distal aorta, usually at the iliac bifurcation, and after confirming
there is no thrombus by back-bleeding the iliac arteries and flushing
the graft, the anastomosis is completed and blood flow opened to the
iliac arteries. If the iliac arteries are aneurysmal and need repair, a
bifurcated aortic graft is sutured to the proximal graft and the distal
anastomosis is to the iliac arteries or to a previously placed aortic
graft in patients who have had previous aortic surgery (infrarenal
aneurysm, aortofemoral graft) or endovascular repair.

Reimplanting Intercostal Arteries
• It is only after finishing the aortic reconstruction that we reattach 2 to
4 intercostal arteries (ICA), which we have previously selected and
preserved. This is done by side-biting the aortic graft and reattaching
the ICA using a button technique we have previously reported82 (Fig.
79.10). Although there are a variety of intercostal reattachment
techniques published, in our opinion only those with in-line flow have
reasonable patency rates, while end-on bypass grafts fail most often
because

Figure 79.10 In the most extensive aneurysms with many open
intercostal arteries we reattach intercostal arteries identified
with preoperative spinal artery MR angiography or by patency
and location between T8 and L2 at surgery, as shown in this
operative photo.

• of low flow. However it should be acknowledged there is no good data on re-implanted
intercostal patency rates. Some surgeons use motor (MEPs) or somatosensory (SSEPs)
evoked potentials or both to select intercostals for reimplantation, but there is little
evidence that using MEPs is any more successful than other selection criteria, although
MEPs may be helpful to monitor adequacy of arterial perfusion pressure.83–87 In
addition, evoked potential monitoring requires assisted circulation to prevent MEP loss
due to peripheral nerve ischemia that occurs with a simple cross-clamp surgical
technique (and in EVAR and TEVAR with occlusive sheaths in the iliac arteries). Loss of
MEPs from peripheral nerve ischemic fatigue interferes with the ability to monitor MEP
changes caused by spinal cord ischemia. Use of assisted circulation simply to monitor
evoked potentials complicates the surgery without providing any demonstrated
reduction in paralysis risk (Fig. 79.11). We reattach intercostal arteries only in the most
extensive aneurysms to reduce the risk of delayed paraplegia and sequence
reattachment at the end of aortic reconstruction so organ, pelvic and lower extremity
ischemia are not prolonged. The goal is to complete the surgery in 3 to 5 hours with as
little blood loss as possible using good surgical technique. Longer operations make it
more difficult for the anesthesiologist to keep the patient stable (Video 79.1).

POSTOPERATIVE CARE
• After open TAAA repair, patients are managed in the intensive care unit for
2 to 4 days depending on clinical progress.
• They are ventilated until adequately awake and able to breathe without
assistance.
• This may be a few hours after repair of a Crawford type 4 aneurysm or 2
days after a Crawford type 2 aneurysm if there are no complications.
• Because patients are intentionally hypothermic to reduce metabolism and
oxygen demand, we let them rewarm gradually with no attempt at rapid
rewarming with Bair Huggers or other heating devices.
• Patients have continuous spinal fluid drainage to keep spinal fluid pressure
below 6 mm Hg until they are awake enough to determine if spinal cord
function is normal.

• After the patient can lift legs, spinal fluid pressure is monitored, but spinal fluid is not drained unless weakness develops.
• Cardiac function and hemodynamics are optimized with adequate volume replacement and inotropic support.
• Mean arterial pressure is kept above 90 mm Hg for the first 48 hours to maximize collateral perfusion of the spinal cord.
• Fresh frozen plasma and naloxone infusions are continued for 48 hours.
• Because of its negative effects following spinal cord ischemia, we do not use morphine for analgesia and prefer fentanyl both intra-
and postoperatively.
• Propofol is used for sedation rather than benzodiazepines because we want the patients to awaken easily for neurologic evaluation
and weaning from the ventilator.
• Delayed paralysis can occur after TAAA surgery.
• Delayed weakness is treated by increasing the mean arterial pressure and cardiac index, draining spinal fluid and restarting
neuroprotective medications.
• In our experience, delayed deficits can sometimes be reversed if interventions are undertaken immediately.
• However, patients that cannot establish adequate collateral circulation to the spinal cord after surgery remain vulnerable to
paralysis if spinal cord oxygen delivery is compromised by decreased cardiac function, hypotension, hypoxemia, or anemia.

POSTOPERATIVE OUTCOMES
Study of surgical outcomes has gone beyond operative and
perioperative mortality and morbidity to include functional recovery
and quality of life measures from the patient’s perspective.

SPINAL CORD ISCHEMIA
• Spinal cord ischemia is a common complication of thoracic aortic repair that can lead to paralysis.
• Adams' paper identified the greater radicular artery (arising from the artery of Adamkiewicz between T8 and
L2 spinal levels in 85% of humans)as the most important factor in this complication due to its vulnerability in
the lower thoracic aorta.
• The risk of paraplegia and decline in spinal cord blood flow during aortic occlusion is related to the number
of open intercostal arteries in the length of the aorta replaced.
• Pruning of intercostal arteries by the disease process leads to autocollateralization that reduces spinal cord
ischemic risk, and physiologic factors impacting perfusion pressure in the collateral network are more
effective at preserving spinal cord function.

Physiologic Spinal Protection
• Etz and Griepp's research on the collateral circulation showed that spinal cord blood flow and recovery of
collateral perfusion pressure occurs rapidly even with no open intercostal arteries.
• The most important factors for optimizing this collateral perfusion network and protecting the spinal cord
until collateral recovery occurs are hypothermia, spinal fluid drainage, high arterial perfusion pressure,
maintaining tissue oxygen delivery, and neurochemical protection.
• Elevated levels of excitatory amino acid neurotransmitters, which are reduced by naloxone, have also been
implicated in exacerbating injury in spinal cord ischemia.
• By applying these experimentally validated principles and interventions, paralysis incidence was reduced by
82%–85% with O/E ratios going from 1 to 0.15–0.18 without assisted circulation or intercostal reimplantation.

Evoked Potential Measurement and
Intercostal Reimplantation
• Surgeons use SSEPs and MEPs to identify critical intercostal arteries for spinal cord protection.
• Intraoperative spinal cord ischemia can be reversed by raising MAP to 100 mm Hg and observing
the return of MEPs.
• Studies have shown conflicting results about the necessity and benefit of intercostal reimplantation,
but reimplantation may play a role in preventing delayed paraplegia in the most extensive
aneurysms.
• Intercostal reimplantation is not the most important factor in paralysis prevention, but it may may
play a role in most extensive aneurysms

PULMONARY COMPLICATIONS
• Pulmonary complications are common after open TAAA repair, with up to 27% of patients experiencing
prolonged ventilation, pneumonia, or respiratory failure.
• Patients who are active or former smokers and have COPD are at higher risk.
• Age, osteoporosis, chronic renal disease, and congestive heart failure can exacerbate these factors.
• The incision itself can reduce lung function postoperatively, and higher incisions make weaning from
ventilator support more difficult.
• Preoperative strengthening regimens may improve strength and functional capacity and possibly reduce
mortality risk.

MORTALITY
• A study of 15,000 patients from 86 published reports in the last 25 years showed an average
mortality rate of 9.3%.
• Patients with acute pathology and those who develop paraplegia account for most of the mortality.
• Operative or postoperative bleeding can cause shock leading to multiorgan failure and death.
• Acute patients are at increased risk due to unstable clinical conditions and lack of screening for
other conditions.
• Mortality rates increase with age and are higher for acute patients than elective surgery.
• Mortality rates have declined significantly in the last 25 years, with half of the improvement in
mortality due to a decline in paraplegia rates. The reasons for the remaining decline may be related
to better centralization of care in larger referral centers and better patient selection.

RENAL FUNCTION
• Poor renal function increases the risk of complications, paraplegia, and mortality in patients
undergoing surgery.
• Postoperative dialysis-dependent renal failure is associated with a 50-60% mortality risk.
• Age and baseline renal function are the most important mortality risk factors.
• Normothermic renal perfusion has not been effective in reducing renal failure.
• Hypothermic renal perfusion appears to provide effective renal protection with dialysis rates of 3%
or less.
•

EFFECT OF SURGICAL TECHNIQUE
ON MORBIDITY
• It is important to understand the mechanisms of injury and protection in aortic surgery to improve results.
• A team approach involving evidence-based and data-driven protocols is necessary.
• The controversy surrounding TAAA repair involves which technique to use, with Assisted Circulation + Spinal Fluid Drainage, Aortic Cross Clamp + SFD, or Hypothermic
Circulatory Arrest being the options.
• Each approach has its strengths and weaknesses, and the choice may depend on patient physiology or anatomy.
• XCL+SFD is surgically simpler but can be more difficult anesthetically, while AC+SFD reduces cardiac strain but is more complicated.
• HCA is the most complicated technique but provides excellent organ protection.
• Total morbidity was comparable between techniques, but there was a significant decline in all categories from Era 1 (1985 to 1997) to Era 2 (1997 to 2008) and
within treatment techniques over time.
•

LONG-TERM
SURVIVAL AND QUALITY
OF LIFE
• Long-term survival after TAAA repair has been studied but there are few studies on quality-of-life
measures.
• Mortality occurs within the first year after surgery from COPD, paraplegia and renal failure, but after
one year the survival curve improves.
• Survival is significantly lower than the general population in all age categories.
• Expected survival is 69%–78% at 1 year and 45%–68% at 5 years depending on the mean age of
the patients in the study.
• Quality-of-life scores were similar to age-matched populations after the first year, but there was a
marked difference in stamina in the older TAAA patients.
• Approximately 80% of patients return to preoperative quality of life.
• Complications such as stroke, dialysis, paraplegia, myocardial infarction or other serious underlying
morbidities severely reduce quality and length of life.

Anesthesia consideration
• Haemodynamic monitoring
• Patient positioning
• OLV/ DLT
• proximal and distal aortic perfusion management
• End-organ (renal, mesenteric and spinal cord)
function monitoring and prevention of dysfunction
• Massive blood loss and coagulopathy.
• Rapid infuser
• Cell saver
• Positional Device

Routine anesthetic
and neurological
monitoring
In patients undergoing
thoraco-abdominal aortic
aneurysm repair
MEPs motor evoked
potentials
SSEPs somatosensory
evoked potentials

Incisions and Aortic Exposure
• Adequate exposure
• Modified right lateral decubitus position
– Shoulders placed at 60 to 80 and the hips flexed to 30 to
40 from horizontal.
– Double-lumen endobronchial tube

Incisions and Aortic Exposure
• Extents I and II
– the upper portion of the thoracoabdominal incision is made
through the sixth intercostal space.
– The posterior portion of the incision is made between the
scapula and the spinal processes
▪ Extent III aneurysms
▪ Seventh or eighth intercostal space
▪ Extent IV aneurysms
▪ Straight oblique incision through the ninth or tenth interspace. The
distal extent of the incision is at the level of the umbilicus.
▪ the incision is gently curved as it crosses the costal margin
• to reduce the risk of tissue necrosis at the apex of the lower portion of
the musculoskeletal tissue flap

Incisions and
Aortic Exposure
A curvilinear incision is used to
approach extent I, II, and III
thoracoabdominal aneurysms.

Extent IV
thoracoabdominal
aortic aneurysms
A straighter, oblique
incision is used to
approach.

Diaphragmatic
preservation
▪Division of only the
muscular portion with
preservation of the
tendinous portion
▪Leads to early ventilator
weaning
▪Diaphragm is divided in a
circular fashion to protect the
phrenic nerve and to preserve
as much diaphragm as
possible
▪A 3- to 4-cm rim of
diaphragmatic tissue is left
laterally and posteriorly to
facilitate closure when the
operation is complete.

DIAPHRAGM SPARING ENTRY
– An intact
diaphragm during
thoracoabdominal
aortic repair
results in a higher
probability of
early ventilator
weaning.
(J Vasc Surg
1999;29:150-6.)
Central tendon is
left intact

The perfusion
systems
▪ FEM- FEM BYPASS
▪ Left heart bypass circuit
to provide distal aortic
perfusion
▪LBP
▪ Cold renal delivery
system to provide selective
renal hypothermia.

LEFT HEART BYPASS
•LEFT ATRIAL DRAINAGE
•LEFT INF. PUL. VEIN
•ARTERIAL INFLOW
•FEMORAL ARTERY
•AORTA AT DIAPHRAGM LEVEL
•HEPARIN 1 mg/Kg
•MILD HYPOTHERMIA 32oC – 34oC
•CLOSE CIRCUIT INLINE
CENTRIFUGAL PUMP
•NO CARDIOTOMY RESERVOIR
OXYGENATOR/WARMING DEVICE
•FLOW RATE = 1.5 – 3 L/min/m2
•PERFUSATE OF RINGER METHYL
PRED AND MANNITOL AT 4oC
•TWO 9 Fr BALLOON CATHETERS
FROM ARTERIAL LINE FOR
VISCERAL PERFUSION
•TWO ADDITIONAL BALOON
CATHETERS FOR RENAL COLD
CRYSTALLOID PERFUSION

LEFT HEART BYPASS
• BENEFITS OF LEFT HEART BYPASS
– Rapid adjustment of proximal arterial pressure
– Effective reduction of preload
– Effective unloading of left ventricle
– Reduced need for pharmacological intervention
– Spinal cord protection by providing the surgeon more time for
creating secure anastomosis
– Lower heparin requirement than formal CPB
• LHB IS MOST BENEFICIAL FOR
– Patients with Suboptimal Cardiac Reserve
– Patients with brittle hemodynamics
– Those with more extensive aneurysm
• LHB IS INDICATED FOR
– All Extent I and Extent II aneurysms
– Selected Extent III aneurysm

FEMORO - FEMORAL BYPASS
• Common femoral artery and vein exposed in the groin
• Transverse arteriotomy for cannulation
• Full heparinisation required , ACT > 400 sec
• 20 – 22 fr. Straight cannula placed in artery
• 21 – 28 fr. , 60 cms long venous cannula inserted with help of
guidewire “ Carpentier cannula “, tip in RA located by TEE
• Core temp – 32 deg.c
• Flow rate – 1.5 – 3 lit / min /m sq.
• Visceral perfusion can be used

FEMORO - FEMORAL BYPASS
• BENEFITS OF FEM FEM – FEM BYPASS
• Improved exposure in the operative field
• Versatility in arterial cannulation
• Myocardial offloading
• Systemic hypothermia protects viscera and spinal cord
• Can be used with DHCA if distal arch also involved
• Enhanced oygenation with single lung ventilation
• Cardiotomy suckers , blood reservoir available
• Reduces dependence of cell saver systems with coagulopathy
• Can be used for selective visceral perfusion

SELECTIVE VISCERAL PERFUSION
• LHB provides flow to mesenteric and visceral vessels🡪
only during initial portion of repair
• After opening the aorta perfusion to adjacent visceral vessels is
delivered using a Y off the arterial line
• Reducing Hepatic Ischemia 🡪
reduces post op oagulopthy
• Reducing Mesenteric Ischemia –
Reduces bacterial translocation from bowel

RENAL PERFUSION
COLD CRYSTALLOID
• Used by Coselli etal
• Lactated Ringer’s Solution
• At 4oC
• In intermittent boluses of
400-600 mL infused for
direct renal cooling
• In a RCT fond to be better
than normo-thermic blood
BLOOD PERFUSION
• Used by other groups
• Blood from LHB circuit
• At 4oC or by some at
normothermia
• Claimed to be more
physiologic

PHARMACOLOGIC INNOVATIONS
FOR SPINAL CORD
– Papaverine (intrathecal)
– Thiopentone
– Methyl Prednisolone
– Magnesium Sulphate
– Adenosine
– Allopurinol
– Prostaglandins
– Mannitol diuresis
– NMDA agonists
FOR RENAL
– Mannitol
– Furosemide
– Dopamine
– Fenoldopam
AHA recommends that use of
these agents SOLELY for
purpose of renal protection
is not indicated
(Class III/Level B)
•Are mainly directed to Spinal Cord & Renal Protection

Replacement 1
PERFUSION-
▪ Femoral vein–to–Femoral
artery bypass is used.
▪Aorta is opened between
clamps and transected
proximally

Descending
Thoracic Aorta
Replacement 2
Patent upper intercostal and
bronchial arteries are ligated
Aortic graft is sutured to proximal
aorta with continuous 3-0 or 4-0
polypropylene suture buttressed
with a strip of
polytetrafluoroethylene (PTFE)
felt.
Distal aortic clamp is repositioned
below aneurysm, and aorta is
incised and transected.

Descending
Thoracic Aorta
Replacement 3
If intercostal arteries below sixth
or seventh intercostal space are
patent, they are excised from
aorta along with
a small cuff of aortic tissue
Opening is made in graft, and
aortic cuff is sutured to graft with
continuous 3-0 or 4-0
polypropylene suture
Clamp on graft is repositioned
below intercostal pedicle to
permit perfusion of intercostal
arteries.
Graft is sutured to aorta with
polypropylene suture buttressed
with a strip of PTFE felt

Repair of an extent II
thoracoabdominal aortic
aneurysm
Extends from the left
subclavian artery to the
aortoiliac bifurcation.

Extent II
thoracoabdominal
aortic aneurysm
Whenever possible,the
phrenic,vagus (indicated by
X),and recurrent laryngeal
nerves are preserved during
the repair.
The isolated segment of aorta
is opened longitudinally and
divided circumferentially a
few centimeters beyond the
proximal clamp.

Thoracoabdominal
aorta replacement
1
Position, incision, Exposure
Diaphragm is divided
Peritoneum in left gutter is incised
vertically, and abdominal viscera and
left kidney are retracted anteriorly and
to the right
Technique employing hypothermic
cardiopulmonary bypass and
circulatory arrest
Left femoral artery and vein are
cannulated, and a venting catheter is
placed in left inferior pulmonary vein.
After circulatory arrest is established,
clamp is placed on lower thoracic
aorta (if possible) to minimize blood
loss.
No clamps are placed on aorta
proximal to diseased segment. Aorta is
opened and transected proximally.

Abdominal aortic segment
exposure
• Via a transperitoneal approach
• Retroperitoneum is entered lateral to the left colon
• A dissection plane is developed in the retroperitoneum anterior to
the psoas muscle and posterior to the left kidney
• Dissection within this plane extends directly to the left
posterolateral aspect of the abdominal aorta.
• The left colon, the spleen, the left kidney, and the ureter are
retracted anteriorly and to the right.
• An entirely retroperitoneal approach can be used in patients with a
hostile abdomen

Thoracoabdominal
aorta replacement
2
Aortic graft, to which a 10-mm
prepared polyester graft is
attached, is sutured to aorta
Patent bronchial and intercostal
arteries above sixth intercostal
space are ligated
Left heart bypass is
stopped
After evacuating air from
circulation of upper body ,
clamp is placed on graft just
distal to the 10-mm graft,
Flow into upper aorta is
established

Thoracoabdominal
aorta replacement
3
▪ Lower aortic clamp is
repositioned below segment of
aorta to be resected,
▪ Flow into femoral arterial
cannula is initiated
▪Hypothermic low flow
established above and below
isolated aortic segment
▪Intercostal and Lumbar
arteries
that will be attached to graft
are isolated with full-thickness
cuff of aorta.
▪This cuff is sutured to graft

Intermittent
visceral perfusion
Balloon perfusion catheters are
inserted into the celiac and
superior mesenteric arteries to
deliver selective visceral perfusion
from the left heart bypass circuit,
And into the renal arteries to
intermittently deliver cold
crystalloid.
Patent lower intercostal arteries
are reattached to an opening in
the graft.

Thoracoabdominal
aorta replacement
4
below intercostal pedicle to
permit perfusing intercostal
arteries
Full-thickness cuff of aortic
tissue surrounding celiac,
superior mesenteric, and
renal arteries is excised from
aorta
Cuff is sutured to graft with
polypropylene suture

Thoracoabdominal
aorta replacement
5
on aorta below renal arteries,
and graft is sutured to distal
aorta

The aorta was
replaced with a multi-branched
graft that facilitated separate
reattachment of each of the
visceral arteries.

CONCURRENT PROXIMAL ANEURYSM
ELEPHANT TRUNK PROCEDURE

REVERSED ELEPHANT TRUNK PROCEDURE

ELEPHANT TRUNK PROCEDURE WITH ENDO STENT

EXTENSIVE ANEURYSM DEBRANCHING STENTING

POST OP B. P. CONTROL
• Vital Importance in first 24 -48 Hrs for Surgical success
– HYPERTENSION 🡪 Can Jeopardize integrity of anastomosis
– HYPOTENSION 🡪 Can Precipitate Ischemic Complications
• SNP and IV Beta – Blockers are used to maintain
TARGET MEAN ABP 80 – 90 mm Hg
IN MARFANS SYND 70 – 80 mm Hg

Post Op Complications
• Bleeding
• Pulmonary complications
• Renal complications
• GI complications
• Spinal Cord Injury

RESULTS FROM VARIOUS STUDIES
COSELLI
2286
AHA
1898
SVENSSON
832
HOUSTON
300
St.
ANTONIUS
OPERATIVE
DEATH
6.6% 4.8% 11%
30 DAY
SURVIVAL
95.0% 92% 92%
PULMONARY
COMPLIACTIONS
32.1% 33% 21%
RENAL FAILURE
(± DIALYSIS)
5.6% 6.9% 4.2%
CARDIAC
EVENTS
7.9%
PRAPLEGIA or
PARAPARESIS
3.8% 3.4% 10% 2.3%
STROKE
(CNS EVENTS)
1.7% 2.7% 3.5% 2.1%
LONG TERM SURVIVAL 73.5%
60 - 38
5y -10y
72 – 60 – 38
3y-5y-10y
79 – 64 – 35
1y-5y-10y
63-34-40-16
5-10-15-20y
FREEDOM FROM
RE-INTERVENTION
96%
13 Year
92-86-83-83

SURVEILLANCE &LIFE STYLE
•ANNUAL CT or MRI
•to detect new aneurysm in other segment/reattachment patches
• ADEQUATE BLOOD PRESSURE CONTROL
•Cessation of Tobacco
•Low salt - low fat diet
•Achieving an ideal body weight
•Not using cocaine or methamphetamines
•Regular aerobic exercise
•Avoiding heavy weight lifting
•Avoiding competitive athletics involving isometric exercise
For patients with a current thoracic aortic aneurysmor dissection,or previously repaired aortic dissection,
employmentand lifestylerestrictions are reasonable, including the avoidanceof strenuouslifting, pushing, or straining
that would requirea Valsalvamaneuver. (Class IIa) (Level of Evidence: C)

SPINAL CORD
PROTECTION
During aortic aneurysm surgery

Blood Supply
Two Systems Exist in close correlation
INTRINSIC
CIRCULATION
INTRINSIC
CIRCULATION
CONSISTS OF ANT &
POSTERIOR
SPINAL ARTERIES
CONSISTS OF
RADICULAR &
OTHER ARTERIES

• Major Radicular Artery
• From T7 ~ L1
• Usually arises from
an INTERCOSTAL A’
• May also arise from
AORTA directly or
from multiple arborizing branches
• Larger than the other
• Most commonly on the LEFT and
• Most commonly SINGLE in number
• On the Right and Bilateral in 10%
• Perfuses the spinal cord distal to junction
with ASA
• ASA above ARM is smaller in diameter than
below the ARM
ARTERY OF ADAMKIEWICZ

INTERRUPTION OF
SPINAL CORD
BLOOD SUPPLY
INCREASED
CEREBROSPINAL
FLUID PRESSURE
INADEQUATE
REVASCULARIZATIO
N
REPERFUSION
INJURY
HYPOTENSION
SPINAL CORD
EDEMA
RESPIRATORY
FAILURE
PRE – EXISTING
INADEQUATE
VASCULARIZATION
DECREASED SPINAL
CORD
OXYGENATION
INTERRUPTION OF SPINAL CORD BLOOD SUPPLY IS CENTRAL TO MECHANISM OF SPINAL
CORD INJURY
DECREASED SPINAL CORD OSYGENTATION IS CENTRAL TO MECHANIS OF “DELAYED” OF
SPINAL CORD INJURY

mechanism
• Thoracic aortic occlusion results in increased
intra cerebral blood flow, which contributes to
the increased CSF pressure .
• An alternative theory postulates that increased
CSF pressure during aortic clamping is related to
volume changes in the venous capacitance beds
located in the dural space.
• Relative spinal cord perfusion pressure
(= Distal mean ABP – CSF pressure) is decreased
leading to neurological complications.

Compartment syndrome of the spinal
cord
Stoppage of normal mitochondrial activity
Reduced ATP , accumulation of intracellular calcium and sodium
Damage to DNA , intracellular edema , acidosis , release of superoxide ions
Release of excitatory neurotransmitters glutamate and aspartate
Accumulation of inflammatory debris in the dural sac with increased pressure ,
leading to compression of spinal vessels

Factors in Spinal Cord Events
�Duration and degree of ischemia during clamp
period .
�Distal perfusion pressure and CSF pressure
�Failure to reestablish flow after aortic
declamping – the no reflow phenomenon
�Post operative factors which may lead to
delayed neurological deficit - upto 3 weeks

Risk factors for post op paraplegia
• Extent of TAAA
• Acute presentation – hypotension and
cardiogenic shock
• Aneurysm rupture
• Aortic dissection
• Duration of aortic cross clamp
• Sacrifice of intercostal or segmental artery
branches
• Occlusive peripheral vascular disease, anemia
• Prior abdominal surgery
• Hypogastric artery exclusion

SEGMENTAL
ARTERY
REATTACHMENT
DISTALAORTIC
PERFUSION
INTRA – OPERATIVE
LOCALIZATION
OF ARM
HYPOTHERMIA
DECREASING SPINAL
ISCHEMIC TIME
PHARMACOLOGICAL
ADJUNCTS
NEWER
INNOVATIONS
PRE – OPERATIVE
LOCALIZATION
OF ARM
CEREBROSPINAL
FLUID
DRAINAGE
RE – ESTABLISHMENT BLOOD SUPPLY IS CENTRAL TO PREVENTION OF SPINAL CORD INJURY
“ADJUNCTS” PLAY EQUALLY VITAL ROLE IN THE PREVENTION AND TREATEMENT

Intraoperative methods to detect cord
ischemia
• Somatosensory evoked potentials
• Motor evoked potentials
• Hydrogen injection method

MEP SSEP
Monitors Anterior Column and thus
MOTOR functions
Monitors the Posterior Column and thus
the SENSORY function
Does not detect changes in the GREY
matter which is more responsible for
paraplegia
Does not monitor the more sensitive
motor conduction system
Correlation between MEP and spinal cord
injury is poor
SEP does not provide information on
reperfusion injury
Monitoring with MEP is affected by
Anaeshtetic Drugs like Propofol, Volatile
Gases, NO2
SEP monitoring is not affected by
anaesthetic drugs
MEP monitoring is unreliable at
temperatures below 25oC, due to
suppression of both axonal and synaptic
transmission
Not affected by temperature
Despite limitations MEP is sensitive and
fast method to detect cord ischemia
Detection of ischemia with SEP is slower
when compared to MEP

Moderate Heparinization
Deliberate hypothermia
Extra – Corporeal Circulation
cerebrospinal fluid drainage
distal aortic perfusion
arterial pressure augmentation

CEREBROSPINAL FLUID DRAINAGE
• Conceptualized by
• Sugie and colleagues (1957)
• Miyomoto and colleagues (1960)
• Cooley and Blaisdell (1962)
• PROPOSED MECHANISM OF PROTECTION IS
• Reduction of CSF pressure increases the Spinal Cord Perfusion Pr
• It counters the abrupt increases in the CSF pressures consequent to
aortic clamping, reperfusion, increased CVP or spinal cord edema
• Meta- analysis of 3 RCTs and 5 Non Randomised Cohort Studies
showed that CSF drainage as an adjunct substantially reduced the
incidence of post operative neurologic impairment (p< 0.0001)
(Cina C. S. et al J. Vasc. Surg. 2004;40:36-44)
• PRESENTLY CLASS I AHA RECOMMENDATION.

CEREBROSPINAL FLUID DRAINAGE
• 18 Fr Eepidural Catheter
• Through L2 – L3 ( orL3 – L4) space
at the time of induction
• Tip advanced 10-15 cm into the SAS
• Left to drain through gravity
whenever pressure is > 10 mm Hg
• Drain is kept for 2-3 days post op
• TARGET PRESSURE
– 08-10 mm Hg during Surgery
– 10-12 mm Hg during Early Post Op
– 12-15 mm Hg once able to move legs
• Before removing the drainage cather
clamp it for several hours to confirm
that discontinuation is safe
• Complication rate is low

Segmental Artery Reattachment
OBSERVATION
• The benefit of reattachment was greater in the lower
thoracic regions especially T-9 to T-12
• Patients in whom the T11 and T12 were either
occluded or reimplanted were significantly at lower
risk of neurological deficit.
• Reimplantation of T9 and T10 was associated with
lower risk of LATE neurological deficit
CONCLUSION
• Reimplantation of T11 & T12 is indicated when these
arteries are patent
• Reimplantaion of T9 & T10 lowers the vulnerability of
the cord to changes in blood and CSF pressure and
thus lowers the risk of late deficit

SEGMENTAL A’ REATTACHMENT
PATENT INTERCOSTALS PROXIMAL TO T6
ARE OVERSEWN PATENT
INTERCOSTALS

Pharmacologic manipulation
�Aim :
Increase of spinal cord blood flow
Metabolic manipulation
Prevention of Reperfusion injury

Pharmacologic neuroprotection
• Glucocorticoid
• Barbiturate or CNS depressants
• Magnesium sulfate
• Mannitol
• Naloxone
• Lidocaine
• Intrathecal papaverine

Current strategy for spinal cord protection during
repair of extent I, II, and III thoraco-abdominal aortic aneurysms
• Permissive mild hypothermia (32–34ºC,
nasopharyngeal)
• Moderate heparinization (1 mg/kg)
• Cerebrospinal fluid drainage
• Motor-evoked potential monitoring
• Left heart bypass during proximal anastomosis
• Aggressive reattachment of segmental arteries
• Sequential aortic clamping when possible

SURGICAL MANAGEMENT of thoracic abdominal aortic aneurysms.pptx

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