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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3925_Библиотеки_им_академика_М_И_Перельмана
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212 Shahriari and Farkas
helpful if the clinical situation allows time for placement of a double-lumen
endotracheal tube.
The patient is positioned in the right lateral decubitus position, with the shoul-
ders at a 90º angle to the operating table and the left groin exposed for TAAs and the
abdomen rotated to 45º for ruptured Thoracoabdominal Aortic Aneurysms (TAAAs).
In cases of ruptured TAAAs, we recommend dealing with the ruptured segment
emergently and repairing the rest of the diseased aorta electively at a later time.
A standard posterolateral thoracotomy is performed, and the chest is entered
through the fourth intercostal space for disease in the distal aortic arch or proximal
descending aorta. The fifth, sixth,
and
seventh intercostal spaces are best used for
the mid to distal descending aorta. In cases of ruptured TAAs, depending on the
extent of the lesion, the sixth intercostal space may be entered and the costal arch
divided for improved exposure. At this point the diaphragm is divided radially and
the retroperitoneum exposed. A selfretaining, multibladed, ring-type abdominal
retractor is of the utmost importance.
Clamp and sew technique: As soon as the chest is entered, the aorta is cross
clamped proximal to the rupture site and fluid resuscitation with blood products and
colloids or crystalloids begun. If the site of rupture is at the distal aortic arch or proxi-
mal descending aorta, then the clamp should be placed proximal to the left subcla-
vian artery, and the subclavian artery controlled by a bulldog clamp. The aorta distal
to the aneurysm is controlled with another aortic clamp. If the patient is in extremis,
with severe shock and acidosis, despite aggressive resuscitation, the operation should
be kept to a minimum even if segments of mildly to moderately diseased aorta are left
behind. In these situations we recommend the clamp and sew technique—where the
aneurysm between the clamps is opened, the intercostal vessels are oversewn, and an
interposition tube graft is anastomozed to the two cut ends of the aorta (without
perfusion adjuncts) (Fig. 5A). These two suture lines initially do not need to be
completely hemostatic. The main objective is to remove the cross clamps as quickly
as possible. This is a situation where technical precision may be sacrificed to some
extent in favor of alacrity. Data has shown that the incidence of paraplegia increases
after 30 min of aortic cross clamping in normothermia (57). Fine hemostasis of the
suture lines can be dealt with after the clamps are removed.
Left atrial to femoral artery bypass: If hemodynamic stability is achieved ini-
tially in the operating room, atriofemoral bypass may be used to perfuse the spinal
cord and the lower body and a more extensive resection may be accomplished, if
needed (Fig. 5B). In these situations the femoral artery or the descending aorta
may be used for arterial cannulation and the left inferior pulmonary vein may be
used for venous return. Using atriofemoral bypass, the distal aortic clamp may be
positioned proximal to T8 and the proximal anastomosis created while the lower
body and the spinal cord are being supplied with oxygenated blood. After the
completion of the proximal anastomosis, the proximal clamp is moved on to the
body of the graft. This is very important, especially if the aorta has been control-
led proximal to the left subclavian artery. In this way, the vertebral artery is
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Treatment of Ruptured Aortic Aneurysms 213
re-recruited, supplying the basilar artery to the spinal cord. The lower clamp is
now moved beyond the distal end of the aneurysm and the distal anastomosis is
created. Appropriate intercostal vessels are attached to the graft using
the island inclusion or “Cobrahead” technique (58). The distal clamp is removed,
the patient is rewarmed, and the chest is closed after decannulation and placements
of chest tubes.
Aortic Arch Rupture
Full cardiopulmonary bypass and deep hypothermic circulatory arrest: For
ruptures proximal to the subclavian artery, clamping proximal to the injury is
rarely feasible and full cardiopulmonary bypass with deep hypothermic arrest is
required (Fig. 6).
The site may be controlled manually, and systemic perfusion can be
accomplished by femoral or direct aortic cannulation. Venous return is provided by
cannulating the femoral vein or main or left pulmonary artery. Cardiopulmonary
bypass is instituted and the patient is cooled to 18ºC. A left ventricular vent is
optional. The heart may be arrested by systemically administering 40 to 60 mEq
KCl for better myocardial protection. This is optional, as the deep hypothermic
arrest itself usually suffices for myocardial protection (Direct delivery of cardiople-
gic solution to the heart is difficult or impossible in this circumstance). Under deep
Figure 5 (A) Clamp and sew technique for ruptured thoracic aortic aneurysm. (B) Left
atrial to femoral artery bypass.
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214 Shahriari and Farkas
hypothermic circulatory arrest, the proximal anastomosis is constructed using a
graft with a sewn-in 10 mm side arm. If the anastomosis is created proximal to the
left subclavian artery, an interposition graft is created between the graft and the left
subclavian artery either during rewarming or at the end of the case. After completion
of the proximal anastomosis, the patient is placed in Trendelenberg, and the arch
and the graft are deaired. A clamp is applied on to the graft distal to the side arm and
perfusion of the ascending aorta and the aortic arch is resumed with a rate of about
30 cc/kg/min flow to the lower body can also be resumed through the femoral can-
nula, with the distal aorta clamped. At this point the patient may be slowly rewarmed
and the distal anastomosis created. All appropriate intercostals vessels between T8
and L2 should be implanted. The distal cross clamp is now removed and the left
subclavian interposition graft is created, if indicated.
Ruptured Thoracoabdominal Aneurysm
Ruptured suprarenal and Crawford level III and IV TAAs are best approached via
a left thoracoabdominal incision as previously described (Fig. 7). For Crawford
level III aneurysms we use the sixth, seventh, or eighth intercostal space for chest
entry and proximal control. For Crawford level IV and suprarenal aneurysms we
use the ninth or tenth intercostals space for entry. The remainder of the exposure
Figure 6 Aortic arch rupture treated using deep hypothermic circulatory arrest.
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Treatment of Ruptured Aortic Aneurysms 215
is carried out as described previously. Again, based on the hemodynamic status of
the patient and the experience of the surgical team, the techniques most frequently
used are clamp and sew or atriofemoral bypass with selective visceral perfusion.
Ruptured Myocotic Aneurysm
Ruptured mycotic aneurysms pose a difficult problem. If the rupture has occurred
in the thoracic aorta, and the patient is hemodynamically stable, then the aneurysm
can be excised and the proximal and distal aortic stumps closed and covered with
healthy muscle flaps or omentum. The patient can then be turned and a median
sternotomy created. Using a tube graft an extra-anatomical bypass between the
ascending aorta and the supravisceral abdominal aorta is created (59). The graft
should be brought from the lateral aspect of the ascending aorta, within the peri-
cardium, behind the inferior vena cava (IVC) and through the diaphragm to the
abdominal aorta within the aortic hiatus of the diaphragm. If the patient is hemo-
dynamically unstable, an aortic cryopreserved homograft wrapped by omentum
(60–63), or a tube graft (64) wrapped by omentum may be used in situ, instead of
the extra-anatomic bypass. These patients should receive chronic antibiotic
therapy tailored to the intraoperative culture results.
Surgical Results
With advances in surgical treatment for elective TAA repair, a perioperative mortality
or neurological injury less than 5% can be expected (65–67). However, the mortality
for repair of ruptured TAA is three to five times higher than that for elective repair
(68–70). In one study, the mean size of the TAAs at the time of rupture was 8.1 cm
Figure 7 Kaplan–Meier cumulative survival. Five-year survival estimates are illustrated for
patients as a function of presentation (P = +0.002). (rx = treatment). Source: From Ref. 23.
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Ye a r s
*at Risk
399 248 221 182 143
109
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emergency surger
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medical rx
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43210
Cumulative Survival
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216 Shahriari and Farkas
(68). Many had previous aortic surgery or chronic Stanford type B dissection, and
were not followed by serial imaging. This again emphasizes the importance of
longitudinal follow-up by teams experienced in aortic surgery and preemptive,
prophylactic repair of the aneurysm to prevent rupture. As shown by Davies et al.
(23) the long-term prognosis for patients surviving ruptured thoracic or TAA is mark-
edly worse than for patients who electively undergo repair of TAA (Fig. 7).
Ruptured Thoracic Aortic Aneurysm and Thoracoabdominal Aortic
Aneurysm—Endovascular Treatment
Although experience with use of endografts in thoracic aortic pathology is grow-
ing, it is still quite limited with regards to its use for ruptured aneurysms.
The only FDA approved device in the United States is the Gore-Thoracic aortic
aneurysm (TAG) (W.L. Gore, Arizona, U.S.A.), however other manufacturers are
conducting trials in preparation for FDA approval. Several institutions outside the
United State are using homemade devices.
From a technical point, once the diagnosis of ruptured TAA has been
established, the patient is rapidly transferred to the OR. The chest, abdomen, and
both groins are prepared as the patient is being anesthetized. If the patient is unsta-
ble, percutaneous femoral arterial access is quickly obtained and a balloon occlu-
sion catheter is passed over a guidewire proximal to the site of the rupture, and the
aortic lumen is occluded (Fig. 8). After anesthetic induction, percutaneous arterial
Figure 8 Balloon occlusion proximal to the rupture site as the first step in endovascular
treatment of thoracic aortic rupture.
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Treatment of Ruptured Aortic Aneurysms 217
access is gained in one groin while a femoral cutdown is performed in the other
groin. An aortogram is performed and the final measurements are carried out in
preparation for the introduction of the endovascular device. The endograft chosen
should be 10% to 20% larger than the measured diameter of the landing zones.
Proximal and distal control of the common femoral artery is obtained and an
arteriotomy created. The delivery sheath is introduced into the aorta through the
arteriotomy. Once the delivery device is in the desired location, the graft is
deployed. A completion aortogram is performed. Any type I endoleaks should be
obliterated by deployment of Gianturco Z-stents (Cook Corporation, Bloomington,
Indiana, U.S.A.).
Morishita et al. (71) have reported on 29 patients treated for acute rupture of
the descending thoracic aorta. The in-hospital mortality was 17%, but these patients
were not immune to pulmonary complications, renal failure requiring dialysis, or
paraplegia (one patient). In another report by Kato et al. (72), 13 patients were
treated for ruptured descending TAA. The in-hospital mortality was 38%. The
endografts were also used in five patients with mycotic aneurysms or aortoesopha-
geal fistulas. Four of these patients died of infections, three of them directly related
to the aortic pathology. Semba et al. (73) reported a survival rate of 80% in
11 patients treated endovascularly for contained rupture of the descending thoracic
aorta. However, these results reflect a selection bias toward patients with contained
ruptures and potentially more stable pathology, as reflected by some of the patients
undergoing treatment as late as 28 days after the onset of symptoms.
These short-term results are encouraging. As our experience with endo grafting
is growing, we are also learning more about the complications and the durability of
this treatment. A detailed discussion of these complications and durability concerns
are beyond the scope of this chapter. However, one must not lose sight of our pri-
mary goal in treating these patients—that is, helping the patient to survive the acute
insult. Thus durability concerns in the ruptured settings are of less importance than
the immediate results. As our experience grows, these devices may offer a tempo-
rary stabilizing solution to a life-threatening problem. Close follow-up is warranted
to permit offering the patient elective, definitive repair if late complications such as
migration, pseudoaneurysm formation, or aneurysm recurrence occurs. Also, we
must not forget that a well-performed open procedure is better than a poorly
performed endovascular option, offered by inexperienced care providers.
Ruptured Abdominal Aortic Aneurysm—Open Repair
For decades open repair of ruptured abdominal aortic aneurysm (RAAA) via
laparotomy has been the mainstay of treatment. The published mortality has
remained between 30% and 70%. Approximately 80% of ruptured aortic aneu-
rysms occur in the infrarenal region. These may rupture into the retroperitoneum
(80%), into the free peritoneal cavity, or present as aorto-caval fistulae. Experience
has shown that to achieve successful outcomes in this complex clinical situation,
an organized system needs to be in place. Several institutions (74–76) have
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218 Shahriari and Farkas
suggested that improved results can be expected from such dedicated pathways.
As with all aortic pathology, a high index of suspicion is required for rapid
diagnosis and triage to appropriate treatment.
Upon diagnosis the patient is quickly transferred to the OR suite. The
patient’s chest, abdomen, and bilateral thighs are prepared as anesthesia is being
induced. A midline laparotomy is performed form the xiphoid process to the pubic
symphysis, and upon entry into the abdominal cavity, the gastrohepatic ligament
is divided and the aortic hiatus identified. Using blunt finger dissection the aorta is
isolated and cross clamped. Care is taken not to injure the esophagus adjacent to
the aorta (Fig. 9). Resuscitation with blood products and intravenous fluids is
commenced. A retractor is positioned such that the small bowel is packed in moist
towels and gently retracted to the right of the abdomen to expose the peritoneum
overlying the aorta. This is incised and the proximal neck of the aneurysm is
identified and clamped. Iatrogenic injury to the left renal vein, renal artery, iliac
veins, inferior vena cava, mesenteric artery and vein, spleen, and duodenum during
this dissection is almost uniformly fatal (Fig. 10) (56).
At this point the supra-celiac clamp can be removed to minimize the
visceral ischemic time. Once the proximal neck of the aneurysm has been clamped,
the aneurysm is cut open and back bleeding from the iliac arteries is controlled
with balloon occlusion catheters. The lumbar arteries are oversewn, and an appro-
priate sized graft is chosen and the proximal and distal anastomoses are created.
If the aneurysm involves both iliac arteries, a bifurcated graft is chosen and an
aorto-bi-iliac anastomosis is created.
Figure 9 High control of aorta for ruptured abdominal aortic aneurysm. (A) Division of
gastrohepatic ligament. (B) Clamping of aorta at diaphragm. Note proximity of esophagus,
which must be protected.
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Treatment of Ruptured Aortic Aneurysms 219
For juxtarenal aneurysms, we maintain the supra-celiac clamp while creating
the proximal anastomosis just distal to the origin of the renal arteries, including
the lower lip of the renal artery orifice in the anastomosis if warranted. Once the
proximal anastomosis is created, the clamp is moved onto the body of the graft
in order to perfuse the visceral vessels. The rest of the operation is conducted
as described earlier. Hemostasis is achieved, the incision reapproximated, and the
patient transferred to the intensive care unit.
When an aorto-caval fistula is suspected on the CT scan or identified intra-
operatively, severe hemorrhage may result from venous bleeding through the
fistula upon opening the aneurysm. In this situation, the assistant uses two sponge
sticks to compress the IVC proximal and distal to the fistula. The orifice of the
Figure 10 Switching clamp to just above the ruptured abdominal aortic aneurysm, thus reper-
fusing the abdominal viscera. (A) Viscera are rotated to the right of the abdomen to expose the
abdominal aorta. (B) Clamp is applied just proximal to neck of aneurysm. (C) Note proximity
of the following structures, whose injury must be avoided: left renal vein, renal arteries, liliac
veins, inferior vena cava, superior mesenteric artery and vein, spleen, and duodenum.
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220 Shahriari and Farkas
fistula is closed with pledgeted nonabsorbable monofilament sutures from within
the aneurysm sac. No attempts should be made to separate the IVC from the aorta
at the fistula, as this maneuver may result in lethal hemorrhage.
Ruptured mycotic aneurysms are rare causes of intra-abdominal aortic
rupture. They are usually secondary to infectious endocarditis or Staphylococcal
bacteremia in the presence of severe atherosclerotic disease. Depending on the
degree of contamination of the aneurysm bed, we recommend complete resec-
tion of the aneurysm, aggressive debridement of the aneurysm bed, and either
the use of a cryo-preserved homograft or the performance of an extra- anatomical
axillo-bi-femoral bypass. Autografting using the patient’s bilateral femoral
veins has also been described and is favored in some institutions. Intraoperatively,
the aneurysm and its bed should be sampled for culture and microbiologic
analysis. We recommend buttressing the retroperitoneal area with omentum
to lessen the risk of aortic stump blowout, anastomotic rupture, or pseudoa-
neurysm formation.
Figure 11 Endovascular repair of ruptured abdominal aortic aneurysm (Montefiore
technique). See text.
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Treatment of Ruptured Aortic Aneurysms 221
Ruptured Abdominal Aortic Aneurysm—Endovascular Repair
Since its introduction in the early 1990s, endovascular abdominal aortic aneurysm
repair (EVAR) has become an accepted treatment for elective AAA repair and has
reduced the associated mortality in appropriately selected patients. Recently
EVAR has also been introduced into the armamentarium for treatment of ruptured
abdominal aortic aneurysm (eEVAR) by institutions highly experienced with this
treatment modality.
There are several designs of aorto-uni-iliac systems, but none of these
devices are FDA approved. One system that has received some attention in this
country is the Montefiore endovascular grafting system (MEGS) designed by the
Montefiore group (77). This system allows rapid deployment of the endograft to
exclude the aneurysm and the site of rupture. The authors suggest a clinical path-
way that includes rapid transfer of patients with ruptured AAAs to the OR. Prior
to induction of anesthesia, a 5Fr sheath is introduced into the brachial artery and
an aortogram is performed. If the patient is hemodynamically unstable, the 5Fr
sheath is exchanged for a 14Fr sheath. A 40 mm compliant balloon catheter is
introduced into the supra-celiac aorta and inflated to achieve proximal control.
Once the aortogram is performed, if the anatomy is suitable for eEVAR, the
Figure 12 Algorithm for treatment of abdominal aortic aneurysm. Source: From Ref. 75.
ER Physician Suspects r-AAA
Alerts On-Cell Vascular Surgery Team:
Vascular Surgeon
Vascular Resident/Fellow
Operating Room
Hemodynamically Unstable Patient
Systolic BP < 80 mm Hg
Hemodynamically Stable Patient
Systolic BP 80? mm Hg
Emergent CTA in ER
Operating Room:
Ready for Endovascular & Open Surgical Repair
Patient in Supine Position Prepped & Draped
General Anesthesia
Femoral Cut-down
Wire Access & Ipsilateral 12 Fr Sheath
Aortic Occlusion Balloon in Distal Thoracic Aorta (if needed)
Angiogram to Evaluate Infrarenal Aortic Neck
Unsuitable Aortic Neck Suitable Aor tic Neck
EVAR
Aortic Occlusion Balloon in Distal Thoracic Aorta
Laparotomy for Open Surgical Repair
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