likely contingent upon the nature of the individual surgeon/institution practice and the available

devices. This percentage of suitable patients has been highly variable with report of 30% in nationwide

series,121 55% in a regional series,122 and 14% to 66% in institutional series.123–125 Notably, the reasons

cited for exclusion include a short infrarenal neck (54%), inadequate iliac vessels (47%), and a wide

infrarenal neck (40%).123

A variety of techniques have been described to overcome the anatomic limitations of the endovascular

approach thereby extending its feasibility. Indeed, some modification has been described to overcome

almost every anatomic contraindication. Stenosis within the access vessels can be overcome by dilation

(i.e., balloon angioplasty, serial dilators) or by the use of an open prosthetic conduit or endovascular

stent graft conduit.126 The open prosthetic conduit is usually anastomosed to the bifurcation of the

common iliac artery and then tunneled through the retroperitoneal space below the inguinal ligament.

Alternatively, an aorto-uni-iliac endograft can be configured and a femoral–femoral bypass performed.

Notably, the patency rates of the femoral–femoral bypass graft in this setting have been reported to be

excellent.127,128 Aneurysm degeneration of the common iliac artery can be overcome by a variety of

techniques including simply using larger-diameter graft limbs, occluding/embolizing the internal iliac

artery and seating the iliac limb in the external iliac artery or by bypassing the internal iliac artery (and

seating the iliac limb in the external iliac artery). Although relatively simple to perform, internal iliac

artery embolization has been associated with a moderate incidence of complications including

buttock/thigh claudication (30% to 40%), sexual dysfunction, neurologic deficit/paraplegia, pelvic

ischemia, and gluteal compartment syndrome.129,130 The claudication improves with time in the

majority of patients, but can be quite debilitating, particularly in patients that did not claudicate

preoperatively. Many of the other complications, although somewhat rare, are irreversible and can be

catastrophic. Because of these concerns, concomitant bilateral internal iliac artery

occlusion/embolization should be avoided when possible. Bypass of the internal iliac artery overcomes

many of these limitations and has been associated with excellent results in terms of long-term graft

patency although the procedure is somewhat challenging and adds significantly to the overall magnitude

of the “less-invasive” procedure.126 Unfortunately, extending the indications for endovascular repair

beyond those recommended by the manufacturers (i.e., instructions for use [IFU]) has been associated

with an increase in the incidence of adverse events including decreased survival and a higher need for

reintervention.131 Iliac bifurcation devices are currently commercially available outside the United

States and will soon be available inside the United States, and will allow for preservation of internal

iliac arteries in select patients with appropriate anatomy.132,133

Consideration of the perioperative and long-term outcomes after EVAR requires introduction of the

concepts of endoleak and endotension. Simply, endoleak is the perfusion of the aneurysm sac outside

the lumen of the endograft while endotension is the persistent pressurization within the excluded

aneurysm sac. Endoleaks have been classified as types 1 through 4 based on the mechanism of the leak

(Fig. 96-8). Type 1 leaks originate at either the proximal or distal attachment sites. Type 2 leaks come

from branch vessels, such as the lumbar or inferior mesenteric arteries. Type 3 leaks are caused by

fabric tears or problems at the graft interfaces of the modular devices, whereas type 4 leaks are usually

transient (<24 hours) trans-graft extravasations that result from the porosity of the graft and needle

holes. It should be emphasized that the entire concept of an endoleak is predicated on the ability to

detect contrast or blood flow outside the lumen of the endograft and is, therefore, contingent on the

sensitivity and specificity of the various imaging techniques. The major concern about both endoleaks

and endotension is that the pressure transmitted to the aneurysm wall may cause the aneurysm to

expand and/or rupture. The clinical significance of the various endoleak types is quite different. Both

type 1 and 3 endoleaks are considered major adverse outcomes associated with an increased risk of

rupture, and they merit urgent/emergent treatment.134 Type 2 endoleaks are generally considered less

worrisome in terms of their rupture risk although they are associated with an increased risk for

reintervention.134 They can generally be followed with serial imaging studies, but merit

evaluation/intervention if the aneurysm sac continues to enlarge. Type 4 endoleaks are self-limited and

benign. The clinical significance of endotension is likewise unresolved. Indeed, the concept itself is

somewhat ambiguous given the limitations of actually measuring the pressure within the aneurysm sac.

It should be noted that freedom from endoleak does not necessarily mean freedom from endotension

given the observation that aneurysms can continue to enlarge in the absence of an identifiable

endoleak.135

The perioperative complication rates appear to be lower after endovascular repair. As noted above, the

randomized, controlled DREAM and EVAR Trials reported a significant decrease in the perioperative

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mortality rate (DREAM – 1.2% vs. 4.6%; EVAR Trial – 1.7% vs. 4.7%).70,79,109 The EVAR Trial also

reported a trend toward a decrease in the combined operative mortality/severe complication rate (9.8%

vs. 4.7%, p = 0.10). Multiple clinical trials have reported that the overall major complication rates

after both endovascular and open repair are approximately 15% although the magnitude of the

complications is less for the endovascular approach and primarily includes vascular access complications

(e.g., hematoma, femoral artery injury).136 These clinical trials have likewise demonstrated that the

total hospital length of stay, intensive care unit length of stay, operative blood loss, and time necessary

to resume normal activities are all less for the endovascular approach.136 In addition, Hua et al.73

reported from the private sector NISQIP database that the perioperative complication rate after

endovascular repair was 24%. Interestingly, the impact on sexual function remains unresolved. A survey

of the DREAM participants demonstrated that sexual dysfunction was common after both endovascular

and open repair, but returned to the baseline state at 3 months for both groups.137 In contrast, Xenos et

al.138 reported significantly less orgasmic and erectile dysfunction after endovascular repair.

Figure 96-8. Type 1 to 4 Endoleaks. Type I and III represent the most dangerous forms of endoleaks, and represent what is

essentially an unrepaired aneurysm. A: Type I leaks originate at either the proximal (Ia) or distal (Ib) attachement sites. Note the

large blush of contrast outside of the graft lumen at the proximal fixation site, demonstrating a type Ia endoleak. B: Type 3

endoleaks are caused by fabric tears or problems at the graft interfaces of the modular devices. Note the contrast blush outside of

the lumen of the graft at the modular interface. Type II endoleaks generally have a more benign natural history, but can cause

aneurysmal growth and rupture. C: Demonstrates an inferior mesenteric arteriogram from a catheter (white arrow) in the

meandering mesenteric artery. Filling of the aneurysm sac through a patent inferior mesenteric artery (red arrow) is evident. D:

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Demonstrates successful embolization of the IMA with coils demonstrated by black arrows. Note no further filling of the aneurysm

sac.

The long-term results after the EVAR and DREAM Trials have failed to document any significant

benefit for the endovascular approach in terms of almost every outcome measure analyzed.79,109

Somewhat surprisingly, there was no difference in all-cause mortality at 2 years in the DREAM Trial

(survival, open – 89.6%, EVAR – 89.7%) or at 4 years in EVAR (mortality, open – 29%, EVAR – 26%).

There were significant differences in terms of aneurysm-related mortality at these time points although

the differences were fairly minimal and their relevance suspect. Both the complication rates (EVAR

Trial; EVAR – 41%, open – 9%) and costs (EVAR Trial; EVAR – ₤13,257, open – ₤9,926) were

significantly greater for the endovascular approach while there were negligible differences in the

quality of life assessments.79,139,140

The mid-term results from the DREAM and EVAR Trials have been somewhat sobering and longerterm outcomes are necessary to further define the role of the endovascular approach. It is clear that the

endovascular approach is not as secure a repair as the traditional, open alternative. The endovascular

repair is associated with ongoing rupture risk that likely approaches 1%/yr.136,141 Notably,

Schermerhorn et al.19 reported a 1.8% rupture risk among Medicare patients undergoing EVAR between

2001 and 2004. The rupture risk has been associated with poor patient selection, operator error,

unrecognized/untreated endoleaks, large aneurysms, and device migration.136,142 Interestingly, the

mortality rate associated with rupture after endovascular repair may be less than for de novo

ruptures.143 Approximately 10% to 20% of patients develop an endoleak during the first year after

endovascular repair.144–146 Admittedly, not all of these require remediation. The excluded aneurysms

can continue to grow and, thereby, represent a risk for rupture. This has been correlated not only with

the presence of endoleak as noted above, but also with the specific device and the baseline aneurysm

size.147,148 Some type of structural failure including fabric tears, hook fractures, and suture breakage has

been reported for almost every device. Design modifications have been implemented to overcome many

of these deficiencies although they represent an ongoing concern that may not be manifest for years. As

a consequence of all these potential limitations, reintervention is sometimes necessary either to prevent

complications or to treat them. Aneurysm-related reinterventions occurred in 3.7% of patients per year

after EVAR from 2001 to 2004 in the Medicare population.149 The majority of these remedial

procedures are minor endovascular procedures, however with a risk of major open procedures of

0.4%/yr.141 In contrast, open aneurysm repair is associated with a less than 1%/yr incidence of

aneurysm-related complications that require remedial procedures in long-term follow-up. Graft-related

deaths have been reported in 2% of patients at 15 years.150

The presence of significant comorbidities and advanced age favors the endovascular approach.

Although the operative threshold in regards to the aneurysm diameter measurement is the same, the

endovascular approach may allow a subset of patients not considered suitable candidates for an open

operation to have their aneurysms repaired. Indeed, EVAR has been shown to be feasible in patients

with hepatic insufficiency151 and consistently safe in octogenarians.152,153 However, a modicum of

clinical judgment is necessary, and the concept that AAA repair is a prophylactic operation and that not

every patient merits treatment must be kept in mind. The EVAR Trial 2 randomized patients not fit for

open repair to expectant management or endovascular repair and demonstrated no difference in

aneurysm-related mortality, all cause mortality, or quality of life.140 Notably, the patients were truly

“high risk” with a perioperative mortality rate of 9% and a 4-year mortality rate of almost 40%. Despite

the potential nephrotoxicity associated with iodinated contrast, chronic renal insufficiency is not an

absolute contraindication to endovascular repair. Strategies to reduce the associated risk can be

employed including the administration of acetylcysteine and sodium bicarbonate.96,97 Alternatively, the

procedure can be performed without contrast altogether by using intravascular ultrasound (IVUS) or

CO2 as the contrast agent. Unfortunately, chronic renal insufficiency is a significant risk factor for

adverse outcome after both open and endovascular repair. Furthermore, multiple studies have shown

that both approaches are associated with a decrement of renal function.154–157 The endovascular

approach may be associated with a greater decrement of function postoperatively, but the findings are

somewhat equivocal; suprarenal fixation of the endovascular device does not seem to be associated with

a greater decrement.157

The known device-related complications and the uncertainty about the long-term outcome after

endovascular repair mandate indefinite surveillance, although the intervals and type of imaging for

surveillance remain controversial. Whatever is chosen by the practitioner, patients must agree to

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comply with the prescribed protocol and their ability or desire to fulfill these expectations should be

factored into the specific choice of procedure. It is important to note that although the incidence of

complications declines with the number of negative postoperative CT scans; new endoleaks have been

discovered many years after device implantation. Similarly, it is imperative that all surgeons that offer

EVAR provide conscientious, long-term follow-up.

The cost comparisons between the open and endovascular approach have been somewhat inconclusive

although the endovascular approach is likely more expensive. Clearly, the EVAR-1 and EVAR-2 trials

demonstrated that the endovascular approach was more expensive.79,140 Although the shorter length of

stay and lower incidence of major perioperative complications have resulted in a reduction in some of

the hospital costs with EVAR, these benefits have been offset by increases in other hospital-related costs,

namely the device cost. Notably, Sternbergh and Money158 reported that the cost of the device

accounted for 52% of the total cost of the endovascular repair and estimated that the costs of open and

endovascular repair were $12,546 and $19,985, respectively in the AneuRx Phase II clinical trial.

Analysis of the hospital costs and reimbursement associated with endovascular repair among 7 medical

centers (university hospital – 3, community hospital – 4) demonstrated a net loss of $2,162.158,159

However, others have reported that the contribution to the hospital margin on a daily basis may be

superior for endovascular repair given the associated shorter duration of stay that permits higher

throughput, fuller overhead amortization, and better use of inpatient beds.160 It is important to note

that most of the analyses have focused on the hospital and device-related costs, but have failed to

include the associated professional fees and the costs associated with long-term follow-up and

reintervention, which all may be substantial. Importantly, Kim et al.161 reported that reimbursement for

endovascular repair does not include long-term surveillance and secondary procedures. Indeed, it has

been reported that the overall cost of endovascular repair may be twice that of the open approach.136

Despite the various advantages and disadvantages of the approaches outlined above, patients and

providers seem to prefer the endovascular approach and these preferences appear to be one of the

driving forces for the widespread application of the technique. Indeed, it is uncommon for patients that

are candidates for either approach to elect open repair. Notably, Williamson et al.162 reported that 18%

of all patients undergoing open repair would not undergo the procedure again. The potential to perform

the endovascular repair completely percutaneously (i.e., no femoral artery exposure) clearly adds to the

appeal of the approach.163,164 It is interesting to note that these patient preferences may not be

sustained. A follow-up study from the DREAM trial reported that patients undergoing endovascular

repair had a better quality of life initially, but those undergoing open repair had a better quality at 6

months and beyond.137

The proverbial “bottom line” for the open versus endovascular debate remains somewhat unresolved,

but the discussion is merely academic at this point. EVAR, when anatomically possible, has essentially

become the standard of care in most practices. Notably, the Agency for Health Care Research Quality

conducted an evidence-based review published in 2006 and concluded that endovascular repair for

aneurysms >5.5 cm did not improve patient survival or health status relative to open repair despite the

fact that the perioperative outcomes were improved.165 Furthermore, they reported that the

endovascular approach was associated with increased cost, complications, need for surveillance and

need for remedial procedures. Finally, they concluded that it did not provide a benefit for patients unfit

for open repair. Despite these recommendations, the trend toward dominance of EVAR over open repair

has increased to a point where many vascular training programs are having difficulty with finding

enough open aneurysm cases to sufficiently teach their trainees.166

OPERATIVE REPAIR

Preoperative Evaluation

The preoperative evaluation of patients undergoing elective AAA repair is similar to that of patients

undergoing any major general or vascular surgical procedure. Patients undergoing endovascular repair

should likely undergo the same preoperative work-up despite the perception that associated

perioperative stresses are less. All patients should receive a complete history and a physical

examination, electrocardiogram, and a chest radiograph. Routine laboratory studies, including a

complete blood cell count with platelets, serum electrolytes/creatinine, and coagulation studies should

be obtained. A specimen should be sent to the blood bank and the appropriate quantity of blood

products cross-matched. This number can be determined from the historic operative transfusion

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