Surgical and endovascular repair of iliac artery aneurysm

INTRODUCTION — Aneurysms of the iliac system affect the common iliac artery (CIA) most often and can occur in isolation or in association with abdominal aortic aneurysm (AAA). Iliac artery aneurysm presents in a variety of ways. Approximately one-half of patients are asymptomatic, and the remaining patients have symptoms related to thromboembolism or to compression of surrounding pelvic structures by the aneurysm. The primary goal of treatment is to prevent iliac artery rupture, which is associated with high mortality rates [1]. When iliac artery aneurysm repair is indicated, an open surgical or endovascular approach can be used. The choice of repair depends upon the clinical presentation, location of the aneurysm, coexistent abdominal aortic aneurysm, and patient comorbidities.

Open surgical and endovascular repair of iliac artery aneurysm will be reviewed here. The clinical evaluation and diagnosis of iliac artery aneurysm are discussed in detail elsewhere. (See "Iliac artery aneurysm".)

INDICATIONS FOR REPAIR — Surgical or endovascular repair of iliac artery aneurysm (IAA) is indicated under the following circumstances (see "Iliac artery aneurysm", section on 'Clinical presentation' and "Iliac artery aneurysm", section on 'Management'):

●Ruptured IAA

●Symptomatic IAA

●Rapidly expanding IAA (≥7 mm in six months or >1 cm in one year)

●Asymptomatic IAA ≥3.0 cm

●Coexistent AAA repair

PELVIC CIRCULATION — An understanding of the pelvic arterial circulation and its rich network of collaterals is important for treating aneurysms of the iliac artery system.

The abdominal aorta, which extends from the diaphragm to the level of the fourth lumbar vertebra, bifurcates into the common iliac arteries (CIAs) (figure 1). The renal arteries arise at the level of the second lumbar vertebra. The lower aortic segment gives off the inferior mesenteric artery and four paired lumbar arteries (L1-L4). The fifth pair of lumbar arteries may arise from the CIAs or from the middle sacral artery.

The CIA is approximately 5 cm in length and divides into the external and internal iliac arteries at the pelvic inlet (figure 2). The external iliac artery (EIA) gives off the inferior epigastric and deep circumflex iliac arteries before passing beneath the inguinal ligament to become the common femoral artery, which perfuses the lower extremity [2].

The internal iliac artery (IIA), also called the hypogastric artery, typically divides into anterior and posterior trunks, though the branching pattern is variable. The branches of the IIA supply the pelvic viscera (colon, reproductive organs), the pelvic and buttock musculature, and the medial aspect of the thigh.

●The anterior trunk branches include the vesical, obturator, middle hemorrhoidal, inferior gluteal, and internal pudendal arteries, and the uterine and vaginal arteries in women.

•The vesical arteries supply the bladder and ureter and, in males, the spermatic cord and prostate.

•The obturator artery supplies the pelvic bone, iliacus muscle, and musculature of the medial thigh, including the adductors and the gracilis muscle.

•The middle hemorrhoidal artery supplies the rectum and collateralizes with the superior and inferior hemorrhoidal arteries, which are derived from the inferior mesenteric and internal pudendal arteries, respectively.

•The inferior gluteal artery supplies the buttock musculature and the posterior aspect of the thigh.

•The internal pudendal artery supplies branches to the external reproductive organs (penis, clitoris). Other branches of the internal pudendal artery include the inferior hemorrhoidal, perineal, and urethral arteries as well as a branch to the pelvic floor musculature.

•The uterine artery supplies the uterus and cervix and gives rise to the vaginal artery.

●The posterior trunk branches include the iliolumbar, lateral sacral, and superior gluteal arteries. The superior gluteal artery is the largest branch, and it divides into a superficial and a deep branch. The superficial branch communicates with the inferior gluteal artery to supply the buttock musculature. The deep branch subdivides into superior and inferior divisions. The superior division joins the deep circumflex iliac artery and the ascending branch of the lateral femoral circumflex artery. The inferior division communicates with the lateral femoral circumflex artery. These vessels supply the buttock musculature and the hip joint [3].

Adequate collateral flow to the pelvic organs is important for preventing ischemia of the pelvic organs during iliac artery embolization procedures. (See 'Internal iliac artery embolization' below.)

Collateral flow comes from aortic (eg, lumbar arteries, middle sacral artery) and inferior mesenteric artery branches (eg, superior hemorrhoidal arteries) and is also present between the anterior and posterior trunks of the IIA as described above.

OPEN SURGICAL VERSUS ENDOVASCULAR REPAIR OF ILIAC ARTERY ANEURYSMS — For elective repair of iliac artery aneurysm in patients with suitable aortoiliac anatomy, in agreement with Vascular Society guidelines, we suggest endovascular repair over open surgical repair [4,5]. Although primary iliac artery patency and mortality rates are not significantly different between open and endovascular repair, endovascular repair is associated with significantly decreased perioperative morbidity, an important advantage given that these patients are older and frequently have important comorbidities. Endovascular repair is also associated with shorter length of stay, and decreased operative time and blood loss. (See "Iliac artery aneurysm", section on 'Epidemiology and risk factors'.)

Iliac artery aneurysm has traditionally been repaired using open surgical techniques. As with abdominal aortic aneurysm, endovascular repair of iliac artery aneurysm is an alternative method for managing iliac artery aneurysm [6].

The advantages of endovascular repair of iliac artery aneurysm include:

●Elimination of the complications associated with pelvic dissection such as:

•Damage to sympathetic and parasympathetic nerves, resulting in erectile dysfunction or retrograde ejaculation

•Disruption of lymphatic channels, resulting in lymphatic leak

●Avoidance of open surgery in patients with prior abdominal or pelvic surgery

●Reduction of perioperative morbidity, thus allowing the treatment of patients at high risk for open surgery

The main disadvantages of endovascular repair are the need for intravenous contrast administration and lifelong surveillance imaging that may increase the risk for renal dysfunction and radiation-related sequelae, respectively.

There are no randomized trials comparing open with endovascular repair of iliac artery aneurysm, and it is difficult to make comparisons because abdominal aortic and iliac artery aneurysms are most often repaired concurrently (open or endovascular); thus, distinguishing the outcomes of the iliac aneurysm repair from the aortic repair is usually not possible [7]. Evidence of the safety and effectiveness of endovascular iliac artery aneurysm repair is derived primarily from observational studies of isolated iliac artery aneurysms, which are less common.

In a systematic review of 13 observational studies of isolated iliac artery aneurysm (mean diameter 4.63 cm), most (181/202) underwent endovascular repair [8]. Perioperative mortality was reduced for endovascular compared with open repair (2.8 versus 8.3 percent). In other reviews, endovascular repair has also been associated with shorter length of hospital stay (1 versus 5 to 10 days), decreased operative time, less blood loss, and decreased need for perioperative transfusion (6 versus 47 percent) [9-12]. There appears to be a higher rate of secondary interventions to maintain stent-graft patency, but long-term iliac artery patency with endovascular repair has not differed significantly from that of open iliac artery aneurysm repair [9-11]. In one longer-term study, five-year primary iliac artery patency rates were 96 percent for endovascular repair and 100 percent for open repair [11].

Mortality rates may be lower in patients undergoing endovascular repair for ruptured iliac aneurysm compared with open iliac aneurysm repair; however, open surgery is more often chosen for the repair of ruptured iliac artery aneurysm due to hemodynamic instability of the patient. Similar to endovascular repair of ruptured abdominal aortic aneurysm, outcomes are biased in favor of endovascular repair. As an example, in a review of 71 patients with iliac aneurysm, 19 patients were treated with open repair and 52 were treated with endovascular repair [9]. There were no deaths in either group for patients who underwent elective iliac aneurysm repair. Seven of the patients presented with rupture, constituting 21 percent of the open group and 6 percent of the endovascular group; the mortality rate was 50 percent in the open group and 33 percent in the endovascular group.

Open repair may be preferred if preserving the internal iliac artery is critical to pelvic flow given that maintaining flow in the internal iliac artery using the available endovascular devices continues to present technical challenges. In the systematic review, at mean follow-up of 32.6 months, the overall incidence of buttock claudication was 13.9 percent [8]. (See 'Branched grafts' below.)

Open repair may also be superior for decompressing the aneurysm sac and relieving symptoms of compression related to large iliac artery aneurysms [13]. (See "Iliac artery aneurysm", section on 'Compression of surrounding structures'.)

PREPARATION — Patients with aneurysmal disease have a significantly higher prevalence of atherosclerotic risk factors compared with age and sex-matched controls. In addition, many patients have a history of smoking. Prior to endovascular or open surgical repair of iliac aneurysm, patients should undergo risk stratification and preventive strategies should be implemented to reduce perioperative cardiac and pulmonary complications. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Evaluation of perioperative pulmonary risk" and "Strategies to reduce postoperative pulmonary complications in adults".)

Antithrombotic therapy — Patients undergoing aneurysm repair (endovascular or open surgery) are considered to be at moderate-to-high risk for deep vein thrombosis, and thromboprophylaxis is indicated. Thromboprophylaxis is discussed in detail elsewhere. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

Prophylactic antibiotics — Prophylactic antibiotics should be given prior to placement of prosthetic material (table 1 and table 2) [14]. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Vascular surgery'.)

Prevention of contrast-induced nephropathy — Endovascular aneurysm repair increases the risk of renal complications, primarily due to the administration of intravenous contrast agents, but potentially also related to embolic debris dislodged by manipulation of catheters and wires. When endovascular repair will be performed in a patient with preexisting renal insufficiency, strategies to reduce the risk for contrast-induced nephropathy should be used [15]. These strategies are discussed in detail elsewhere. (See "Prevention of contrast-associated acute kidney injury related to angiography".)

OPEN SURGICAL REPAIR — For patients with iliac artery aneurysm that meet criteria for repair (see 'Indications for repair' above), the approach to open surgical management depends upon the segment of the iliac tree that is affected (common, internal, or external iliac artery) and the presence of coexistent abdominal aortic aneurysm (AAA) [16].

Open repair of iliac artery aneurysm is performed under general anesthesia. A midline or retroperitoneal approach can be used; the choice depends largely upon the location of proximal vascular control. Aortic control requires laparotomy or a retroperitoneal approach. Control of the iliac arteries in the pelvis can be achieved through a low abdominal or retroperitoneal (transplant) incision. (See "Incisions for open abdominal surgery", section on 'Midline incision' and "Incisions for open abdominal surgery", section on 'Oblique incisions'.)

Common iliac artery aneurysm — Patients with bilateral common iliac artery aneurysms or patients with coexistent AAA are managed with aorto-bi-iliac or aorto-bifemoral graft placement [16]. Even in the absence of AAA, the origin of the graft in patients with bilateral iliac artery aneurysms should be just below the renal arteries, as if AAA were present, due to the increased risk of future aneurysmal aortic wall degeneration. The general technique for bifurcated graft placement is discussed elsewhere. (See "Open surgical repair of abdominal aortic aneurysm".)

Large common iliac artery aneurysms associated with compressive symptoms should be opened and repaired directly (endoaneurysmorrhaphy) to decompress the aneurysm sac rather than performing ligation and bypass. Interposition grafting of the common iliac artery is performed similar to open aortic aneurysm repair [17]. Direct open repair of the common iliac artery also maintains collateral flow to the pelvis via the lumbar arteries and the inferior mesenteric artery, thus reducing the risk of postoperative colonic ischemia [18]. Once the vessel is opened, retrograde bleeding is oversewn from the interior of the vessel and the graft sutured into place [19]. Resection of the aneurysm sac is not necessary, as it only increases the risk of bleeding and injury to adjacent structures, particularly the ureter, which can be adherent to the wall of the aneurysm [20].

Isolated common iliac artery aneurysms can be repaired without necessarily exposing and clamping the aorta, provided the proximal common iliac artery has minimal calcification, has normal diameter, and can otherwise be safely exposed and clamped. Avoiding aortic dissection and clamping also eliminates ischemia to the contralateral lower extremity, reduces the risk of cardiac and pulmonary complications, and shortens the recovery period [21]. In a retrospective review of 34 patients with isolated iliac artery aneurysms, none of the 32 patients who underwent open repair required aortic clamping [18]. In this study, morbidity was minimal, and there were no deaths.

Operative repair of internal iliac artery aneurysm — Operative treatment of patients with an internal iliac artery aneurysm (IAA) may consist of endoaneurysmorrhaphy with graft interposition (opening the aneurysm sac and placing a graft), aneurysmectomy (aneurysm resection), or proximal and distal internal iliac artery ligation [13,22]. Interposition grafting maintains antegrade pelvic flow and should be used in the setting of bilateral IAAs when one side will require ligation. Aneurysmectomy may be necessary for a large aneurysm that is causing compressive symptoms.

Ligation has the advantage of limited pelvic dissection; however, despite proximal and distal internal iliac artery (IIA) ligation, the aneurysm sac may fail to decompress due to retrograde filling through collateral branches. Each of the IAA branch vessels must be individually ligated to eliminate the back-bleeding [22]. (See 'Pelvic circulation' above.)

ENDOVASCULAR REPAIR — The goal of endovascular repair is to exclude the aneurysm sac from the circulation. Factors that influence the endovascular approach include the length of the normal artery proximal and distal to the aneurysm (proximal and distal landing zones), involvement of the internal iliac artery, bilateral versus unilateral aneurysmal disease, and presence or absence of a coexistent abdominal aortic aneurysm (AAA) [23]. The specific procedure may involve bifurcated aortic endograft placement or isolated iliac stent-graft placement, each with or without adjunctive embolization of the internal iliac artery [1,23,24]. We agree with Vascular Society guidelines revascularization of at least one internal iliac artery during endovascular treatment of aortoiliac aneurysms and bilateral iliac aneurysms involving the external iliac/internal iliac bifurcation [4,5].

Endovascular repair of iliac artery aneurysm can be performed with local anesthesia and sedation, which allows treatment of patients who might otherwise have a high risk for perioperative surgical morbidity. Conversion to an open repair is uncommon but may be needed in the event of a technical complication that cannot be managed by endovascular means.

Associated abdominal aortic aneurysm — Coexistent abdominal aortic aneurysm and common iliac artery aneurysms can be treated simultaneously with a bifurcated aortic endograft. Patients with concomitant iliac artery aneurysm and AAA must fulfill criteria for the placement of a bifurcated endovascular aortic graft. (See "Endovascular repair of abdominal aortic aneurysm", section on 'Anatomic suitability'.)

If the common iliac artery is aneurysmal at the takeoff of the internal iliac artery, then coil embolization of the internal iliac artery and graft extension into the external artery is performed (image 1). Internal iliac artery flow can be preserved by landing the iliac graft limb into the distal common iliac artery, provided an adequate seal can be obtained (picture 1) [25]. The criteria for iliac aneurysm repair in this setting are discussed elsewhere. (See "Iliac artery aneurysm", section on 'Iliac artery aneurysm associated with abdominal aortic aneurysm'.)

Branched grafts — In patients with a coexisting AAA and a common iliac artery aneurysm that extends to the internal iliac artery takeoff, the internal iliac artery may be able to be preserved with an iliac branched-endograft device. This device has a side limb that fits into the internal iliac artery, while the main limb extends down the external iliac artery (figure 3). Thus, flow is maintained into the internal iliac artery but is excluded from the aneurysm sac (image 2 and picture 2) [26-29]. In a systematic review that included 2736 patients undergoing unilateral or bilateral iliac branch device placement for aortoiliac aneurysm or isolated iliac artery aneurysm, the success rate of placement was high (98 percent) [30]. Overall, endoleak occurred in 11.9 percent, and reintervention in 7.6 percent [30]. The pooled estimate for buttock claudication was significantly lower for bilateral iliac branch device placement (0.7 percent) compared with unilateral iliac branch device placement and contralateral internal iliac artery embolization (7.9 percent), and for bilateral iliac artery embolization/coverage (33.8 percent). Sexual dysfunction was also reduced for iliac branch device placement compared with embolization.

Isolated common iliac artery aneurysm — The endovascular management of isolated common iliac artery aneurysms depends upon the length of normal artery proximal and distal to the aneurysm (proximal and distal landing zones) and the proximity of the aneurysm to the internal iliac artery [8,10,31-33].

Placement of a stent-graft into the common iliac artery requires at least 15 mm of nonaneurysmal artery proximal to the iliac aneurysm to prevent encroachment of the graft on the aortic bifurcation and to allow an adequate seal to prevent endoleak [34,35]. Additionally, 15 mm of normal artery distal to the iliac artery aneurysm but proximal to the takeoff of the internal iliac artery avoids covering the origin of the internal iliac artery (figure 4).

Under circumstances where these anatomic criteria are not satisfied, isolated common iliac artery aneurysm can be managed in the following manner:

●No proximal landing zone – Isolated common iliac artery aneurysms without an adequate proximal landing zone are treated with an aorto-iliac endograft as with concomitant abdominal aortic aneurysm (figure 5) [36]. (See 'Associated abdominal aortic aneurysm' above.)

●Adequate proximal but no distal landing zone – If the distal landing zone is not adequate, the internal iliac artery will need to be sacrificed, unless a branched iliac device is available (see 'Branched grafts' above). Prior to stent-graft placement, the origin of the internal iliac artery is embolized with thrombogenic coils or by using a vascular plug device to prevent back-bleeding from the internal iliac artery into the aneurysm sac from pelvic collaterals (figure 6). The stent-graft in the common iliac artery can then be extended distal to the origin of the internal iliac artery to normal-caliber external iliac artery for fixation.

Internal iliac artery embolization — Internal iliac artery (ie, hypogastric) aneurysms are most commonly treated with a combination of embolization and stent-grafting, but embolization alone can also be used. Adequate coil embolization of internal iliac artery aneurysms requires interruption of the blood flow into the aneurysm (origin of the internal iliac artery) and outflow from (internal iliac artery branches) the aneurysm to effectively arrest flow within the aneurysm sac, which will then thrombose (figure 7) [19]. (See 'Pelvic circulation' above.)

Embolization of the internal iliac artery interrupts pelvic blood flow to the hemipelvis and is associated with a 12 to 55 percent risk of buttock claudication and a 1 to 13 percent risk of erectile dysfunction [29,37-41]. A systematic review of observational studies assessed the effects of internal iliac artery occlusion (30 studies) or internal iliac artery revascularization (27 studies) during endovascular treatment of aortoiliac aneurysms. The incidence of buttock claudication was 36.5 percent in the occlusion group and 4.1 percent in the revascularization group [38].

In a study of 48 patients with aortoiliac aneurysms undergoing bilateral coil embolization of the internal iliac arteries, buttock claudication developed following the procedure in 42 percent of patients initially and was persistent in one third of these patients at one year [42]. Impotence occurred in 14 percent of patients, and there were no cases of buttock necrosis or ischemic colitis. (See 'Complications' below.)

When bilateral embolization is chosen, a staged approach with one to two weeks between procedures may allow the development of pelvic collaterals. In the first stage, either of the internal iliac artery (IIA) aneurysms is embolized, and in the second stage, the other IIA aneurysm is embolized in conjunction with aortic endografting, if needed. However, two small nonrandomized studies that compared simultaneous with sequential IIA embolization found lower rates of ischemic complications with simultaneous embolization; however, the event numbers were small [43,44]. In the absence of more convincing evidence, many clinicians prefer staged repair when bilateral IIA aneurysms complicate endovascular aortic aneurysm repair.

COMPLICATIONS — The complications associated with open surgical and endovascular repair of iliac artery aneurysm in conjunction with abdominal aortic aneurysm repair are discussed elsewhere. (See "Complications of endovascular abdominal aortic repair".)

The incidence of complications during open repair, excluding cardiac and pulmonary morbidity, ranges from 3 to 22 percent [45]. Complications include lower extremity ischemia due to graft thrombosis or distal embolization during intraoperative manipulation, pelvic ischemia from disruption of internal iliac artery flow [19,46], refilling of the aneurysm sac from retrograde collaterals resulting in rupture [21], arterio-enteric fistula [21], graft infection, and ureteral and iliac vein injury [46].

The incidence of perioperative morbidity with endovascular repair ranges from 10 to 23 percent [45]. The most common complication is endoleak, occurring in 0 to 7 percent of patients, and, if untreated, endoleak is associated with an approximately 40 percent rupture rate. Access site complications at the femoral artery include groin infection, hematoma, and pseudoaneurysm formation [47,48]. Other complications include graft stenosis, thrombosis, or graft kinking [49], and distal embolization (due to guidewire manipulation during stent deployment) [49]. These may lead to symptomatic lower extremity ischemia. Distal embolization occurs in 1 to 2 percent of patients during endovascular repair of iliac artery aneurysm [50], slightly more frequently compared with open iliac aneurysm repair. In a retrospective review that included 300 endovascular and 350 open aortoiliac aneurysm repairs, severe foot ischemia occurred in seven endovascular repairs compared with three open repairs [50].

Pelvic ischemia is an important complication of the treatment of iliac artery aneurysm and can occur with open surgical or endovascular repair [19]. Ligation, coverage with an endograft, and coil embolization of the internal iliac artery are all associated with an increased risk of buttock claudication, pelvic muscle necrosis, lower extremity neurologic deficits, spinal cord ischemia, impotence, and ischemic colitis [51]. Preservation of one or both of the internal iliac arteries, whenever possible, is preferred to avoid these complications [52].

Continued surveillance is important to monitor for endoleak, sac enlargement, or stent migration, as illustrated by the following studies:

●In a review of 61 iliac artery aneurysms (common: 41, internal: 19, external: 1) treated with endovascular repair (34 unilateral iliac stent grafts, 8 bifurcated aortic stent-grafts, 3 coil embolizations), five endoleaks occurred at one-month follow-up, with four additional endoleaks identified on later follow-up imaging [48]. No late ruptures occurred at a mean follow-up of 22 months.

●Another review of 91 patients who underwent endovascular repair for isolated iliac artery aneurysm reported complications in 20 percent of patients that included seven type I endoleaks, three type II endoleaks, two enlarging aneurysm sacs (incomplete embolization), five cases of buttock claudication, and two stent-graft thromboses [53]. Two patients required conversion to open surgery, and 10 patients (11 percent) underwent secondary interventions.

ANEURYSM SURVEILLANCE — Following repair of iliac artery aneurysm, annual evaluation including a complete vascular exam should be performed to identify the development of other large vessel aneurysms [45]. (See "Iliac artery aneurysm", section on 'Site of aneurysm and association with other aneurysms' and "Iliac artery aneurysm", section on 'Surveillance ultrasound'.)

Lifelong surveillance is necessary for patients treated with endovascular techniques. Computed tomographic (CT) angiography and ankle-brachial index measurements should be performed at 30 days, six months, and one year. If no problems are noted at one year, follow-up can be limited to annual CT scan or abdominal ultrasound to assess stent-graft patency, identify any endoleaks, and evaluate changes in aneurysm sac diameter [54,55]. If there is an increase in the aneurysm sac diameter or the patient develops symptoms, more frequent surveillance or arteriography may be indicated [49].

MORTALITY — Perioperative mortality with elective iliac artery aneurysm repair is low, near zero for endovascular repair and 0 to 6 percent for open repair [9,11]. Perioperative mortality rates for ruptured iliac artery aneurysm are higher compared with elective repair but significantly lower for endovascular compared with open surgical repair [9,11,12]. In a review of a 12 year experience at a single institution, perioperative mortality was 6 and 17 percent for elective and emergent open repair of isolated iliac artery aneurysms, respectively [11]. In another review, 10 percent of the patients presented with rupture [9]. The mortality rate was 50 percent for those who underwent open surgery compared with 33 percent who underwent endovascular repair. As discussed above, patients are more often selected for open repair when iliac artery aneurysm ruptures; thus, outcomes are biased in favor of endovascular repair. (See 'Open surgical versus endovascular repair of iliac artery aneurysms' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Aortic and other peripheral aneurysms".)

SUMMARY AND RECOMMENDATIONS

●Iliac artery aneurysm – Factors that influence the choice of iliac aneurysm repair include the segment of the iliac tree that is affected (common, internal, or external iliac artery), coexistent abdominal aortic aneurysm, the length of normal artery proximal and distal to the aneurysm, involvement of the internal iliac artery, bilateral versus unilateral aneurysms, patient comorbidities, and resources available at the treating center. (See 'Introduction' above.)

•Aortoiliac aneurysm – Iliac artery aneurysms that are associated with abdominal aortic aneurysm are treated with a bifurcated graft or endograft. (See "Open surgical repair of abdominal aortic aneurysm" and "Endovascular repair of abdominal aortic aneurysm".)

•Isolated iliac artery aneurysm – For isolated common iliac artery aneurysms, a stent-graft can be placed across the aneurysm. Embolization of the internal iliac artery may become necessary if the distal landing zone is inadequate. Alternatively, a direct open approach can be used. Internal iliac artery aneurysms can be embolized, ligated, or directly repaired. (See 'Endovascular repair' above and 'Open surgical repair' above.)

●Internal iliac artery management – Whenever possible, normal pelvic arterial flow should be preserved. Interruption of unilateral or bilateral internal iliac arteries should be undertaken only after careful consideration of the risks. Unilateral internal iliac artery embolization may be warranted in selected patients after acknowledging the risk of side effects such as buttock claudication and sexual dysfunction. Bilateral internal iliac embolization should be avoided but may be needed in life-threatening situations. (See 'Operative repair of internal iliac artery aneurysm' above and 'Internal iliac artery embolization' above and 'Complications' above.)

●Elective repair with suitable anatomy – For elective repair of iliac artery aneurysm in patients with suitable aortoiliac anatomy, we suggest endovascular repair rather than open surgical repair (Grade 2C). Endovascular repair is associated with significantly decreased morbidity, which is an important advantage given that these patients are older and frequently have important comorbidities. Primary iliac artery patency rates are similar between open and endovascular repair. (See 'Open surgical versus endovascular repair of iliac artery aneurysms' above.)

●Ruptured iliac artery aneurysm, large aneurysm, or aneurysm with challenging anatomy – Open repair is often necessary for hemodynamically unstable patients with iliac artery aneurysm rupture, and open repair may be superior for relieving symptoms of compression related to large iliac artery aneurysms. Open repair should also be considered if the available iliac branch devices are not suitable taking into consideration the perioperative risks. Open repair may be preferred if preserving the internal iliac artery is critical to pelvic flow. (See 'Open surgical versus endovascular repair of iliac artery aneurysms' above.)