Congenital variations in the kidney anatomy may complicate the repair of an AAA. Specifically, aberrant

kidney anatomy may complicate the dissection during open repair because they are frequently

associated with multiple renal arteries, aberrant venous return, and abnormally positioned ureters. The

various congenital anomalies of the upper urinary system have been classified in an attempt to

standardize the approach for vascular surgeons.308 The anomalies have been broken down into

abnormalities of position, including simple ectopia, and abnormalities of both form and fusion,

including horseshoe kidney, crossed renal ectopia without fusion, and crossed renal ectopia with fusion.

An ectopic kidney may be positioned anywhere from the pelvis to the thorax. Common forms of ectopic

kidney include the pelvic kidney, located opposite the sacrum and below the aortic bifurcation; the

lumbar kidney, located opposite the sacral promontory in the iliac fossa and anterior to the iliac vessels;

the abdominal kidney, located above the iliac crest adjacent to the second lumbar vertebra; and the

thoracic kidney, which can be located above the diaphragm in the posterior mediastinum. In a

horseshoe kidney, two distinct renal masses are fused together by either a bridge of renal parenchyma

or fibrous tissue; in the overwhelming majority, the lower poles are fused. In crossed renal ectopia, the

kidney mass is located on the side opposite to its insertion in the bladder. Multiple configurations of

crossed ectopia with and without fusion have been described.

The preoperative objective for the various renal anomalies is to image the renal mass adequately,

delineate the course of the ureter, and establish the arterial and venous supply. The approach is

simplified by the fact that most patients undergo abdominal/pelvic CT as part of the preoperative

evaluation. The location and position of both the kidneys and ureters, like the position of the left renal

vein, should be established as part of the review of every CT scan for patients with aneurysms.

Formerly, it was recommended that patients with renal anomalies undergo preoperative arteriography

to confirm the location and number of renal arteries. However, this information can now be obtained

from the CT arteriogram, which is now part of the routine preoperative evaluation.

Patients with renal anomalies can safely undergo repair of an AAA using either an open or

endovascular approach.309–311 However, the anomalies must of course be factored into the operative

plan. The specific operative approach depends on the location of the renal mass, blood supply, course of

the ureters, and presence of fusion. A left-sided retroperitoneal or transperitoneal approach with medial

visceral rotation is the most helpful for open repair, particularly in patients with a horseshoe kidney. A

standard transperitoneal approach with transection of the fused parenchyma can be used in patients

with a horseshoe kidney although this may be associated with both significant bleeding and a urine leak

and, therefore, is discouraged. The frequently encountered multiple renal arteries can be handled most

expeditiously by using a Carrel patch technique, in which a cuff of aorta including the renal artery

orifices is reimplanted into the aortic graft after completion of the proximal anastomosis. Endovascular

repair is possible in many cases with the feasibility dictated by the location of the renal arteries in

addition to the other standard anatomic considerations. Use of the endovascular approach may require

covering at least one of the renal vessels and has been associated with loss of some renal

parenchyma.309

Coexistent Renal or Visceral Artery Occlusive Disease

Coexistent renal or visceral artery occlusive disease is frequently found in patients undergoing AAA

repair. The optimal management of patients with coexistent lesions remains unresolved. The options

include repair of the aneurysm alone, simultaneous repair of the aneurysm and revascularization of the

renal or visceral vessels, and staged repair, with either aneurysm repair or revascularization performed

first. Furthermore, the specific treatment options include both open and endovascular alternatives for

the aneurysm repair and visceral/renal revascularization (i.e., angioplasty/stent). The rapid expansion

of the endovascular technologies has afforded effective, safe approaches that have replaced open

surgical revascularization for both renal and visceral artery lesions to a great degree. Regardless, the

optimal approach represents a balance between the indications for the procedure and the associated

added risk.

Renal/visceral revascularization is mandatory at the time of open aneurysm repair if the affected

vessels are involved in the aneurysm, as in a suprarenal aneurysm or a horseshoe kidney. More

commonly, a lower pole or accessory renal artery may arise from the aneurysm. The decision to

perform a concomitant revascularization with either reimplantation or a bypass graft in this setting

depends on the size of the vessel and the quantity of kidney parenchyma perfused. Revascularization is

recommended for larger vessels (>2 mm) that supply a significant portion of the renal mass. The

presence of any accessory renal arteries should factor into the operative plan and the general feasibility

2758

for endovascular repair. Covering small, accessory renal arteries has been reported to be safe, although

it must be appreciated that this approach sacrifices some renal parenchyma.312

Combined aneurysm repair with renal or visceral artery revascularization may be justified if the

indications for renal or visceral artery revascularization are satisfied. The traditional indications for

renal revascularization included poorly controlled hypertension in a patient with a significant renal

artery stenosis and rapidly progressive renal insufficiency in a patient with adequate renal mass and

bilateral renal artery stenosis. However, the antihypertensive agents have improved to the point that

renal revascularization is currently reserved for patients with poor blood pressure control despite

optimal medical therapy with at least three separate medications, including a diuretic.313,314

Endovascular treatment of the renal artery stenosis (when indicated) can be performed prior to open

aneurysm repair or simultaneous with the endovascular approach. Although feasible, simultaneous open

aneurysm repair and renal artery bypass is associated with a significant increase in the operative

mortality rate relative to the aneurysm repair alone.315,316

The traditional indications for mesenteric revascularization include symptoms of chronic mesenteric

ischemia and critical stenosis of either the SMA alone or two of the three visceral vessels. Patients with

chronic mesenteric ischemia and AAAs should have their visceral occlusive disease corrected prior to

aneurysm repair when possible. Repairing the aneurysm first potentially increases the risk of developing

acute mesenteric ischemia in the perioperative period, and performing concomitant mesenteric

revascularization with AAA repair carries significant morbidity/mortality over and above that seen with

open mesenteric revascularization alone.317–319 Endovascular treatment with stent placement is probably

the optimal treatment for the visceral lesions in this setting because of its simplicity, despite the

concerns about its longer-term durability.320–322

The optimal treatment for patients with aneurysms and asymptomatic renal or visceral artery lesions

remains poorly defined. Natural history studies with the use of both arteriography323 and duplex

scanning324 have suggested that significant renal artery stenoses are preocclusive lesions that may merit

intervention. However, analysis of patients with asymptomatic renal artery stenosis who underwent

aortic reconstruction found that the natural history of the renal artery lesions is fairly benign when

untreated and is associated only with an increase in the antihypertensive requirements.325 Little is

known about the natural history of asymptomatic mesenteric occlusive lesions. However, a small report

has suggested that patients with asymptomatic severe mesenteric occlusive disease involving all three

visceral vessels have a high incidence of bowel infarction.326 Ultimately, consideration should be given

to mesenteric revascularization prior to aneurysm repair in patients with severe visceral artery occlusive

disease due to the potential risk of mesenteric infarction at the time of aneurysm repair as noted above.

Additional Concurrent Intra-abdominal Disease

The finding of an AAA and an additional intra-abdominal process that may require operative repair is a

frequent event. A second surgical problem may be identified as part of the preoperative evaluation or

discovered at the time of the exploratory laparotomy during open aneurysm repair. Alternatively, an

AAA may be identified during the surgical treatment of another problem. No algorithms have been

defined for the management of such concurrent problems, and the overall approach certainly requires

sound clinical judgment. Options include simultaneous performance of the necessary operations, or a

staged operation with repair of the AAA as either the first or second procedure. The approach depends

on the risk for aneurysm rupture, natural history of the second surgical problem, and potential for

infection of the prosthetic graft during simultaneous repair. Notably, both the laparoscopic and

endovascular approaches have impacted the approach to patients with combined problems due to their

reduced morbidity and mortality facilitates a more rapid, definitive treatment.

The generic recommendation for patients with an AAA and an additional intra-abdominal surgical

problem is that the most life-threatening problem be addressed first. The natural history of untreated

AAA has been defined reasonably well and has been outlined extensively earlier in this chapter. It has

been suggested that the risk for aneurysm rupture is increased after major intra-abdominal surgery and

that it is potentially related to an increase in collagenase activity.327 However, this reported increased

rupture risk is speculative and should not necessarily be factored into the decision algorithm. The

management of concurrent colon cancer and AAA is a frequent treatment dilemma that provides an

excellent illustration of the approach to these problems. Indeed, the reported incidence of colon cancer

and an AAA occurring simultaneously ranges from 0.5% to 2.1%.205 The treatment principles suggested

by Szilagyi et al.328 included the following: (a) aneurysm repair first in the presence of rupture; (b)

colon resection first in the presence of hemorrhage, perforation, or obstruction; (c) aneurysm repair

2759

first in the presence of a large aneurysm and a small colon cancer; (d) colon resection first in the

presence of a large colon cancer and a small aneurysm.

Simultaneous AAA repair and cholecystectomy is probably safe for patients with cholelithiasis or

evidence of chronic cholecystitis. The safety of these simultaneous procedures has been documented in

several series, and the concerns about an increased incidence of aortic graft infection have not been

substantiated.329 Advocates of the simultaneous approach justify the cholecystectomy by the potential

requirement for a cholecystectomy in the future and the morbidity and mortality associated cholecystitis

after aneurysm repair.329 Although a consensus is not found in the literature, simultaneous AAA repair

and cholecystectomy are recommended only if evidence of chronic cholecystitis or multiple small stones

is present. Regardless, the cholecystectomy and other simultaneous procedures should not be performed

until after the aneurysm repair is completed and the retroperitoneum closed in an attempt to reduce the

hypothetical risk for graft infection.

The safety and utility of other simultaneous procedures remain poorly defined although a wide range

of procedures have been combined with open aneurysm repair.202–205 The repair of ventral hernias is

often mandatory to achieve a tension-free abdominal closure and should be viewed more as an

extension of the aneurysm repair than as a simultaneous procedure. Inguinal hernias may be repaired at

the time of aneurysm repair, but it is uncertain whether the small risk associated with a subsequent

procedure at a later date offsets the obligatory additional time for the simultaneous repair.

Appendectomy330 and small-bowel excision for Meckel’s diverticulum329 have been reported to be safe

when performed concomitantly with aneurysmectomy although the natural history of the associated

underlying problems in the usual age group of patients undergoing AAA repair is relatively benign.

2760

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