ultrasonography or CT may confirm the diagnosis. The anterior and lateral aspects of the aortic wall are

thickened and hypoechoic on the sonogram. The CT findings are characteristic and include a thick,

contrast-enhancing wall in the distribution described. An inexperienced observer may confuse the CT

findings with those of a ruptured AAA. Hydronephrosis with medial displacement of the ureters is

frequently seen in contradistinction to the lateral displacement seen with noninflammatory aneurysms.

Indeed, this entity may share some pathophysiologic pathways with retroperitoneal fibrosis.

The treatment of inflammatory AAAs is essentially the same as that for the more common,

noninflammatory variety. Nonoperative treatment with corticosteroids has been advocated in the past,

although this approach is likely ineffective and has largely been abandoned.271 It has been suggested

that the rupture risk of inflammatory aneurysms is less than that for noninflammatory variety because

the wall thickness is increased. However, this is not true, and patients should not be lulled into a false

sense of security. It should be emphasized that most aneurysms rupture through their posterior or

posterolateral aspect, which is not involved in the inflammatory process. The open repair of an

inflammatory AAA is complicated by the fact that the adjacent structures, including the duodenum,

colon, and ureters, may be involved in the process and densely adherent to the aortic wall. Using the

retroperitoneal approach can reduce the technical difficulties associated with the open repair. The

operative blood loss and procedure time associated with the open repair of inflammatory AAAs may be

greater than the more common, uninvolved type. These potential technical difficulties should be

factored into the operative indications and size-related threshold for the open approach.

EVAR may be the optimal treatment for patients with inflammatory AAAs due to the concerns about

the inflammatory process and adherent structures outlined above.272–275 Notably, Puchner et al.275

performed a meta-analysis of patients undergoing endovascular repair for inflammatory aneurysms and

reported that the inflammatory process resolved in approximately 50% of the cases. Inflammatory

aneurysms can be repaired through a transperitoneal approach, and this scenario occasionally arises

when the diagnosis is not suspected preoperatively. Regardless of the open approach, no attempt should

be made to mobilize the adherent structures, specifically the duodenum, because of the potential for

accidental injury. Proximal aortic control can be achieved either immediately above the renal arteries or

above the visceral vessels. Alternatively, intraluminal aortic control can be achieved with a balloon

catheter, although this approach is less appealing. Distal control can usually be achieved at the common

iliac arteries or at the level of their bifurcation. The duodenum and other adherent structures should be

mobilized by incising the wall of the aneurysm and then reflecting them laterally. The proximal

anastomosis can usually be performed to the infrarenal aorta from the inside of the aneurysm after

opening the wall. The preoperative placement of ureteral catheters, particularly lighted catheters if

available, may facilitate their identification intraoperatively and can be helpful in patients with

hydronephrosis. An increased incidence of anastomotic pseudoaneurysms has been demonstrated in

patients with inflammatory aneurysms after open repair and justifies long-term surveillance.276,277

Juxtarenal and Suprarenal Abdominal Aortic Aneurysms

The management of aneurysms extending to the level of the renal arteries or more cephalad is more

complicated, and, predictably, the morbidity and mortality rates associated with open repair are

increased.278–280 Interestingly, several recent reports from centers of excellence have documented

mortality rates comparable to those reported for infrarenal repairs although it is unlikely that these

findings are applicable nationwide.281–283 Repair of these complex aneurysms is complicated by the

obligatory period of renal and visceral ischemia associated with aortic occlusion during the proximal

anastomosis. Indeed, the renal complication rates range from 15% to 20% even from these select

centers of excellence.281–283 These increased morbidity and mortality rates should be factored into the

decision algorithm and threshold for operative repair. Elective operative repair is usually recommended

for patients with aneurysms 6 cm or larger in diameter in this setting although the 5.5-cm criterion may

be appropriate for very good-risk patients and those with juxtarenal aneurysms who will require only a

short period of suprarenal aortic occlusion.

AAAs extending to the renal arteries or more cephalad may be repaired via either a retroperitoneal or

a transperitoneal approach although the former is optimal, especially with more cephalad disease. The

retroperitoneal approach, with anterior reflection of the left kidney, obviates the concerns about the left

renal vein (except when a retroaortic renal vein is present) and simplifies exposure of the abdominal

aorta. The distal descending thoracic aorta is easily exposed by incising the diaphragm and its crus. Of

note, the right renal artery and right common iliac artery are more difficult to expose via the

retroperitoneal approach because of their trajectory of those vessels, but this is not prohibitive in most

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cases. The proximal anastomosis may be fashioned as a long beveled anastomosis incorporating the

orifices of the renal and visceral arteries, or a Carrel patch can be fashioned from the aortic segment

with reimplantation or bypass of the left renal artery in situations where the aneurysm involves the

entire visceral segment.

For juxtarenal aneurysms repaired through the transperitoneal approach, the aorta can be clamped in

the supraceliac or suprarenal position, depending on the extent of the disease and the patient’s body

habitus. Suprarenal clamp is preferred to avoid unnecessary visceral ischemia. Of course, if the

aneurysmal tissue extends above the renal arteries, a supraceliac clamp may be required. The

supraceliac exposure is similar to that described above for a ruptured infrarenal AAA, but performed in

a more controlled fashion. After mobilization of the left lobe of the liver, the esophagus should be

reflected left laterally. Placement of a nasogastric tube facilitates identification of the

esophagus/gastroesophageal junction. The gastrohepatic ligament should be divided making note of

aberrant hepatic arterial anatomy to avoid dividing a replaced hepatic vessel during this portion of the

dissection. The crus of the diaphragm can be divided bluntly or sharply followed by division of the

dense connective tissue surrounding the aorta for placement of the clamp. If a clamp is to be placed in

the suprarenal position, this is facilitated by retracting the left renal vein superiorly or inferiorly after

ligating its adrenal, gonadal, and lumbar branches. As noted previously, the left renal vein may be

ligated near its confluence with the vena cava without adverse sequelae.206 The collaterals of the left

renal vein (e.g., adrenal) should be preserved when using this approach; thus, the decision to divide this

vessel should be made early. The anterior surface of the aorta at the level of the visceral vessels is

encased by dense neural tissue, which can be incised. Incising the crus of the diaphragm that envelops

the lateral aspect of the aorta further facilitates clamp application. The configuration of the proximal

anastomosis in the setting of the transperitoneal approach depends on the extent of the aneurysm and

the vessels involved.

EVAR for juxtarenal AAAs has become widely available with the FDA approval of fenestrated aortic

grafts.8,284–287 The approach is based upon constructing a suitable landing zone for the more traditional

endograft in patients with an inadequate or short infernal neck. This is accomplished using an

individually designed fenestrated endograft that contains orifices that correspond to the renal and

visceral vessels. These fenestrations permit the introduction of individual covered stents. The worldwide

experience with fenestrated EVAR is vast, and the technique has been shown to be feasible, safe, and to

prevent aneurysm rupture in the short term.8,284–287

Further progression of repair into the visceral segment with branched/fenestrated repairs using

custom aortic grafts, surgeon-modified devices, and parallel stent techniques such as “chimney” EVAR

are an ongoing revolution in aortic repair, and have demonstrated acceptable results in both elective

and urgent/emergent clinical scenarios. The profound complexity in the device-to-device and device-toaorta/branch vessel interactions with these types of repair certainly make their durability questionable,

and close follow-up of these patients is warranted.288,289

Combined endovascular and open (i.e., “hybrid”) approaches have also been used to treat the

juxtarenal and more complex proximal aneurysms. These techniques are based upon constructing a

suitable aortic neck to land a traditional endograft by “debranching” the renal or visceral vessels. For

example, a suitable landing zone below the superior mesenteric artery (SMA) could be created for a

juxtarenal aneurysm by performing bilateral iliorenal bypasses. Although theoretically appealing, a

number of reports have demonstrated that mortality rates for the hybrid approach for complex

aneurysms have been comparable to open repair, and these repairs have largely fallen out of favor in

many centers.290–292 Indeed, the magnitude of the revascularization procedure appears to be comparable

to that of the more traditional open repair and, accordingly, the approach does not appear to extend the

indications for aneurysm repair to older, sicker patients. Thus, branched/fenestrated repairs may be

more suitable in these patients, if a repair is warranted at all.

Infected Abdominal Aortic Aneurysms

Infected AAAs comprise a small subset of all AAAs, accounting for less than 1% of all repairs.293 The

term mycotic aneurysm coined by William Osler to describe aneurysms that developed after septic

cardiac emboli caused an arterial infection, has often been used to refer to all infectious etiologies for

aneurysms. Unfortunately, “mycotic” is a misnomer that has led to a significant amount of confusion. A

more specific classification system consists of four groups based on the underlying mechanism: (a)

classic “mycotic aneurysm” caused by embolus from the heart infecting an artery; (b) microbial

arteritis, in which bacteria infects an atherosclerotic but nonaneurysmal artery and leads to aneurysmal

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degeneration; (c) an existing aneurysm that becomes infected; (d) traumatic pseudoaneurysm with

concomitant bacterial inoculation.294 Microbial arteritis resulting from hematogenous bacterial spread

currently accounts for approximately 80% of all cases of infected aortic aneurysms.295,296 Salmonella

causes approximately 40% of all aneurysmal infections in contemporary series with the remainder

caused by Staphylococcus, Streptococcus, Bacteroides, Arizona hinshawii, Escherichia coli, and Pseudomonas

aeruginosa.294

The diagnosis of infected aortic aneurysm is often difficult and the clinical presentation insidious.

Patients may present with fever, back/abdominal pain, or both. The physical examination is often

remarkable for a palpable abdominal mass and the presence of peripheral emboli. Laboratory studies

are notable for an elevated leukocyte count and positive blood cultures although the latter are present

only 50% of the time296,297 and negative blood cultures do not exclude the diagnosis. CT is the most

useful diagnostic study, and the features suggestive of an infected aneurysm include a periaortic mass,

an aneurysm in an atypical location, periaortic fluid or gas, retroperitoneal inflammation, and frank

rupture. The angiographic finding of a saccular or eccentric/irregularly shaped aneurysm in an atypical

location is also suggestive of an infected aneurysm.

The treatment of an infected aneurysm requires control of hemorrhage in the presence of rupture,

aggressive debridement of all infected tissues, and restoration of perfusion to the viscera and lower

torso. Indeed, these treatment concerns and the management options are identical to those for patients

with infected aortic grafts, which is a more common problem. Patients should be started on broadspectrum antibiotics when the diagnosis is suspected although antibiotic therapy alone is not sufficient

and the operative intervention should not be delayed in an attempt to sterilize the retroperitoneum.

Patients with suspected rupture should undergo emergent exploration through either a transperitoneal

or retroperitoneal approach. After vascular control has been obtained, the retroperitoneum should be

explored, and intraoperative cultures along with stat Gram stain should be obtained. Several options for

arterial reconstruction are available, depending on the clinical scenario and the individual patient’s

anatomy. These options include in situ replacement with a prosthetic or cadaveric graft, ligation of the

infrarenal aorta with extra-anatomic bypass (axillo-femoral, femoral–femoral configuration), or in situ

replacement with staged extra-anatomic bypass and subsequent removal of the in situ graft. The choice

is contingent on the character of the aorta, degree of inflammation in the retroperitoneum, suspected

organism, and hemodynamic status. In situ replacement of the infected aneurysm with a prosthetic or

cadaveric graft is a reasonable option if retroperitoneal inflammation is minimal and the Gram stain is

negative. The integrity of the aortic stump at the time of ligation and the potential for dehiscence or

breakdown of the suture line are major concerns. The aorta should be debrided back to grossly

uninvolved tissue and sutured in two layers with a running horizontal mattress and a simple continuous

technique using nonabsorbable monofilament suture. A pedicle of omentum can be mobilized and

approximated next to the aortic stump to help control the retroperitoneal inflammation and minimize

the risk for stump dehiscence. When the diagnosis is suspected preoperatively and no evidence of

rupture is found, a staged approach with extra-anatomic bypass followed by graft removal may decrease

the physiologic impact of any one procedure. The procedures are usually performed 2 to 3 days apart to

allow the patients a period of recovery. Patients should be anticoagulated between procedures to

prevent thrombosis of the extra-anatomic bypass resulting from competitive flow. Fortunately, the risk

of graft thrombosis and graft infection during the intervening period is small.

Endovascular repair of infected aortic aneurysm has been reported and can be considered an

additional alternative.298 Although the long-term safety of EVAR in this clinical scenario remains

unclear, it may serve as a temporizing approach that converts an urgent problem to an elective one. A

recent meta-analysis by Kan et al.299 reported that the endovascular approach was reasonable, but the

incidence of subsequent endograft infection was significant in patients with ruptured aneurysms and

those with fevers. They concluded that endovascular repair could be used as a bridge in this setting (i.e.,

ruptured aneurysm, febrile) prior to definitive open repair.

Infected aneurysms involving the suprarenal aorta pose a particularly challenging problem, but

fortunately are uncommon. In situ replacement with a prosthetic or cadaveric graft is frequently the

only available option, which can be accomplished in a number of ways, but the principle of aggressive

removal of all infected tissue should be adhered to in order to avoid recurrent infection, which is

typically a fatal event. If the thoracic aorta is of good quality, an antegrade debranching of the visceral

segment can often be accomplished, and limits the ischemia time to the visceral/renal vessels. If there is

a contained rupture of the aorta, or the tissues are particularly inflamed, it may be best to obtain

proximal and distal control above and below the disrupted/infected segment before attempting to

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dissect the visceral/renal vessels from the inflammatory mass, which may rupture during dissection.

After obtaining sites for proximal and distal aortic control, a branched prosthetic graft soaked in

Rifampin is sewn to the aorta in an end-to-side manner using a side-biting clamp on the thoracic aorta,

allowing antegrade perfusion during the anastomosis. It is important to leave enough good aorta below

this bypass to allow a cross-clamp and separate end-to-end anastomosis. The left renal, SMA and celiac

artery can be bypassed individually in some cases and then a cross-clamp placed on the aorta distal to

the end-to-side graft. The aorta is then transected and aggressively debrided leaving just the right renal

origin, when possible. A separate tube or bifurcated graft can then be sewn from the distal thoracic

aorta to the bifurcation of the abdominal aorta, or to the iliac/femoral arteries, as indicated. This

technique limits the ischemia time on the individual viscera/renal arteries, and allows full removal of

all atherosclerotic material and infected aorta along with the infected periaortic tissues after complete

revascularization of the visceral segment.

Patients with infected aneurysms, regardless of the arterial reconstruction, require long-term

antibiotics and follow-up. Patients should receive intravenous broad-spectrum antibiotics until cultures

are available, with the total of 6 weeks of intravenous antibiotics. If culture-directed therapy is not

possible, broad-spectrum antibiotics for 6 weeks is indicated. The patient should then be placed on oral

antibiotics although the duration of treatment remains unresolved and many surgeons will treat the

patient with lifelong suppressive antibiotics. In addition, patients should undergo serial CT scans to

assess the retroperitoneum and the status of the in situ graft when applicable. The follow-up imaging

regimen is typically dictated by the clinical scenario, but a CT at 2 weeks, 3 months, 6 months, and then

at 6- to 12-month intervals thereafter, is common. In the event that stable imaging is obtained over the

first few CT scans, later imaging may not be warranted. Predictably, the morbidity and mortality rates

associated with infected AAAs are significant with a 40% mortality rate reported in a recent

publication.300

Aortoenteric Fistulae

An aortoenteric fistula is a communication between the aorta and the bowel. The duodenum is involved

most commonly at the site where it crosses anterior to the aorta, but the communication can develop

between almost any portion of the intestine. Primary aortic fistulae result when an aortic aneurysm

erodes into the bowel and are distinctly rare with a reported incidence of 0.04% to 0.07% in autopsy

series.301 Debonnaire et al.302 identified 18 primary aortoenteric fistulas through a survey of 196

Belgian surgeons and reported a mortality rate of 30%. Secondary aortic fistulae result from the erosion

of a prosthetic aortic graft into the bowel; are significantly more common, with a reported incidence of

0.1% to 2.0% after aortic reconstruction.303 Notably, they can also occur after EVAR.304 The

management of both primary and secondary aortic fistulae is the same.

The diagnosis of an aortoenteric fistula is often difficult and mandates a high index of suspicion.

Patients usually present with gastrointestinal bleeding manifested as either hematemesis or melena. The

initial episode of gastrointestinal bleeding is often self-limited and has been described as a “herald”

bleed. The diagnosis of aortoenteric fistula should be foremost among the differential when a patient

with a known aneurysm or prior aortic reconstruction presents with intestinal bleeding. Patients should

undergo endoscopic evaluation of the upper and lower intestinal tract to determine the source of

bleeding. It is imperative that the clinical suspicion of an aortoenteric fistula be communicated to the

endoscopist to ensure that the third and fourth portions of the duodenum are adequately examined,

which is not typically done during routine foregut endoscopy. The endoscopic findings of erosion,

thrombus, active bleeding, or visible prosthetic graft in third or fourth portion of the duodenum are

diagnostic of an aortoenteric fistula and mandate emergent treatment due to the risk of massive

hemorrhage. Mild duodenitis and gastritis without frank erosion are frequently seen at the time of

endoscopy and do not exclude the diagnosis of an aortoenteric fistula. Notably, the findings during

upper endoscopy are normal in up to 30% of patients with a documented aortoenteric fistula.305 A CT

should be performed if the results of endoscopy are inconclusive. The findings on CT that suggest an

aortoenteric fistula include inflammation within the retroperitoneum, an anastomotic pseudoaneurysm,

close approximation of the bowel and the prosthetic aortic graft or aneurysm, and loss of the normal

tissue planes between the duodenum (or any other bowel segment) and the aorta or prosthetic graft.

Occasionally, both endoscopy and CT are nondiagnostic despite the clinical suspicion of an aortoenteric

fistula. Exploratory laparotomy is recommended in this setting for both diagnosis and treatment.

Adherence of the bowel to the aorta at the time of the initial exploration suggests an aortoenteric fistula

and mandates obtaining suitable proximal and distal control of the aorta, iliac vessels, or prosthetic

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graft before further dissection. The diagnosis cannot be excluded until the bowel is entirely separated

from the retroperitoneum and graft.

The treatment of an aortoenteric fistula requires repair of the defect in the gastrointestinal tract in

addition to repair of the aneurysm or treatment of the infected prosthetic graft. Treatment of the

gastrointestinal defect is usually straightforward and is based on standard surgical principles.306 After

the fistula is disassembled, the edges of the bowel can be debrided and a primary closure performed. A

limited bowel resection or enteral diversion may be necessary. The intraoperative and longer-term

management of the aortic aneurysm or prosthetic graft is the same as that outlined above for infected

aortic aneurysms. In situ replacement of the prosthetic graft or infrarenal aorta using autogenous

femoral vein or cryopreserved aortic allograft, ligation of the infrarenal aorta with excision of the

prosthetic graft and extra-anatomic bypass, or temporary in situ aortic replacement with staged extraanatomic bypass and subsequent graft excision are all reasonable options. The decision algorithm is

based upon the hemodynamic stability of the patient, their baseline physiologic state, and the anatomy

and involvement of the aorta. In older/sicker patients, the most expeditious procedure is probably best,

which is often in-line replacement of the infected graft with a Rifampin-soaked Dacron graft. If the

patient stabilizes afterward, a planned graft excision with aortic stump ligation and extra-anatomic

axillary–femoral–femoral bypass can be performed. Replacement of the infected graft using autogenous

femoral vein (neo-aorto-iliac system [NAIS]) is reasonably well tolerated in younger/healthier patients,

and may be a better option that obviates the risk of aortic stump blow-out. If the visceral segment is

involved, ligation of the aorta may not be possible without sacrifice of the renal arteries, and

replacement using cryo-preserved aortoiliac conduit, rifampin-soaked Dacron, or autogenous femoral

vein may be the best options. In any case, these patients should be maintained on long-term antibiotics

and undergo serial imaging studies, as outlined for infected aneurysm patients.

Venous Anomalies

Anomalies of the vena cava and renal veins are occasionally encountered at the time of aortic

reconstruction. The common anomalies are related to the embryologic development of the iliac veins

and vena cava. The four most clinically relevant anomalies include duplication of the inferior vena cava

(0.2% to 3.0%), left-sided vena cava (0.2% to 0.5%), circumaortic left renal vein (1.5% to 8.7%), and

retroaortic renal vein (1.2% to 2.4%).307 Patients with a duplicated inferior vena cava have large veins

that run parallel to the infrarenal aorta and join together either anterior or posterior to the aorta at the

level of the renal vein. In the case of a left-sided inferior vena cava, the cava runs parallel to the left

side of the aorta, and the normally located right-sided vena cava is absent. The left-sided vena cava

typically crosses the aorta at the level of the renal vein to become the suprarenal inferior vena cava,

and the gonadal and adrenal veins on the right drain directly into the renal vein in a mirror image of

the normal anatomy. The circumaortic left renal vein forms a collar of veins that surrounds the aorta at

the normal level. In the case of a retroaortic left renal vein, a single vein runs posterior to the aorta at a

slightly more caudal location. Notably, both duplication of the inferior vena cava and left-sided vena

cava can be associated with other venous anomalies, including a circumaortic or retroaortic renal vein.

The diagnosis of the various venous anomalies can usually be made preoperatively on CT.

Identification of the vena cava and left renal vein should be part of the mental checklist used when the

preoperative CT scans are reviewed. The various anomalies may not become evident immediately in the

operating room if missed on the preoperative imaging studies. A very prominent left renal vein at the

usual location or slightly inferior is suggestive of a left-sided vena cava, whereas the absence of a left

renal vein despite dissection along the anterior aspect of the aorta at the level of the SMA is suggestive

of a retroaortic renal vein.

Open repair of an infrarenal AAA in a patient with a venous anomaly is essentially the same as the

standard approach although additional care should be exercised to prevent inadvertent injury of the

aberrant vein. Exposure of the infrarenal neck is more difficult in the presence of a duplicated or leftsided vena cava. However, sufficient exposure can usually be obtained by gentle dissection and

mobilization of the venous structures. The presence of a duplicated or left-sided vena cava is a relative

contraindication to the left retroperitoneal approach, but is not absolutely contraindicated. A

circumaortic left renal collar or retroaortic left renal vein presents a potential hazard when the proximal

aortic clamp is applied. A vertical aortic clamp is recommended and obviates the dissection on the

posterior aspect of the aorta. Transecting the aorta may facilitate exposure of a retroaortic renal vein

when significant bleeding is encountered.

Renal Anomalies

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