Results section

Original Article

Surgical and Endovascular Management of Isolated Internal Iliac Artery Aneurysms: A Systematic Review and Meta-Analysis

Paolo Perini, MD1,2 , Erica Mariani, MD2, Mara Fanelli, MD2 , Alessandro Ucci, MD2, Giulia Rossi, MD2 , Claudio Bianchini Massoni, MD, PhD1,2 , and Antonio Freyrie, MD, PhD1,2

Abstract Objectives: The purpose of this paper is to report the different modalities for the treatment of isolated internal iliac artery aneurysms (IIIAA), as well as their outcomes. Methods: We performed a systematic review of the literature (database searched: PubMed, Web of Science, Scopus, Cochrane Library; last search: April 2020). We included articles reporting on the outcomes for IIIAA interventions comprising at least 5 patients. Studies were included when presenting extractable outcome data regarding intraoperative and/or early results. We performed meta-analyses of proportions for different outcomes, using random effects model. Results: Thirteen non-randomized studies were included (192 patients with 202 IIIAA). IIIAA were symptomatic in the 18.1% (95%CI 9.3-26.9; I2 54.46%, P ¼ .019). Estimated mean IIIAA diameter was 46.28 mm (95%CI 39.72-52.85; I2 88.85%, P < .001). Open repair was performed in 21/202 cases. Endovascular treatments were: embolization (81/181), embolization and hypogastric artery coverage (79/181), hypogastric artery coverage by stent-grafting (15/181), stent-grafting in the hypogastric artery (6/181). Overall estimated technical success (TS) rate was 91.6% (95% CI 86.8-95.5; I2 45.82%, P¼ .031). TS rate was 94.5% for open surgery (95%CI 85.3-100; I2 0%, P ¼ .907), and 89.7% for endovascular repair (95%CI 83.8-95.6; I2 55.43%, P ¼ .006). Estimated overall 30-day mortality was 3.1% (95%CI 0.8-5.4; I2 0%, P¼ .969). Mortality rates after open surgery and endovascular repair were 8.2% (95%CI 3.4-19.8; I2 0%, P ¼ .545) and 2.8% (95%CI 0.5-5.1; I2 0%, P ¼ .994), respectively. Estimated mean follow-up was 32.63 months (95%CI 21.74-43.53; I2 94.45%, P < .001). During this timeframe, IIIAA exclusion was preserved in 92.8% of the patients (95%CI 89.3-96.2; I2 0%, P ¼ .797). Buttock claudication occurred in 13.9% of the patients (95%CI 8.7-19.2; I2 0%, P ¼ .622). Conclusions: IIIAA are frequently large, and symptomatic at presentation. Several treatments are proposed in literature, open and endovascular, both with good results. The endovascular treatment is the preferred method of treatment in literature, since it offers good short- to mid-term results and low early mortality. Buttock claudication after hypogastric artery exclusion is a common complication.

Keywords internal iliac artery, hypogastric artery, aneurysm, embolization, buttock claudication

Introduction

Iliac artery aneurysms (IAA) are commonly associated with

abdominal aortic aneurysms (AAA). In fact, aorto-iliac aneur-

ysms represent approximately the 10% of AAA.1 Isolated IAA,

without involvement of the infrarenal aorta, have an overall

reported frequency up to 7% of all aorto-iliac aneurysms, and are

more frequently localized in the common iliac artery (CIA).1,2

Isolated internal IAA (IIIAA) represent a rare entity, accounting

for 0.3-0.5% of all intra-abdominal aneurysms.3

The great majority of patients with IIIAA are asymptomatic,

even though rupture or symptoms of local compression may

occur.4,5 However, due to the widespread use of computed tomo-

graphy angiography (CTA) over the last decades, their preva-

lence, as well as their detection at an asymptomatic stage, is

increasing.1 Even though guidelines currently suggest treatment

when the diameter passes 35 mm, solid data are lacking, and

patient’s fitness and feasibility of open vs. endovascular treat-

ment should be considered to define the threshold for repair.1

Furthermore, a rapid increase in size is not currently a clear

1Vascular Surgery, Cardio-Thoracic and Vascular Department, University

Hospital of Parma, Parma, Italy 2Vascular Surgery, Department of Medicine and Surgery, University of Parma,

Parma, Italy

Corresponding Author:

Paolo Perini, Vascular Surgery, Cardio-Thoracic and Vascular Department,

University Hospital of Parma, Via Gramsci, 14, 43126 Parma (PR), Italy.

Email: [email protected]

Vascular and Endovascular Surgery 2021, Vol. 55(3) 254-264 ª The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1538574420981812 journals.sagepub.com/home/ves

indication in present guidelines for this sub-group of

aneurysms.1

In fact, due to their rarity, the natural history of IIIAA,

as well as treatment outcomes, are not well known, and

low evidence is available to suggest the best treatment

modality.

The goal of this systematic review and meta-analysis was to

analyse the peri-operative and mid- to long-term results of the

treatments proposed in literature for IIIAA. We focused on

technical success, mortality and maintenance of aneurysm

exclusion over time (considering absence of endoleaks and sac

shrinkage).

Materials and Methods

Data Sources, Search Strategy, and Selection Criteria

This study was undertaken in accord with the “Preferred

Reporting Items for Systematic Reviews and Meta-Analysis

(PRISMA)” statement.6 Papers on IIIAA which underwent

treatment were looked for in PubMed, Web of Science, Scopus

and the Cochrane Library. We also searched cross-references.

On the April 19, 2020, we performed the last search. The

following words were searched in PubMed: “(“hypogastric

aneurysm” OR “internal iliac aneurysm” OR “hypogastric

artery aneurysm” OR “internal iliac artery aneurysm”) AND

(“treatment” OR “repair” OR “correction”)”. The database

research was undertaken by 2 authors (PP and CBM), indepen-

dently. Controversies were solved by a third author (AF).

We included papers which reported about the outcome of

different treatments for IIIAA, when presenting a cohort of

at least 5 patients. Non-English articles were included when

an English abstract with extractable data was provided.

Inclusion criteria were: (i) patients with IIIAA of athero-

sclerotic/degenerative etiology; (ii) treatment of the IIIAA

by endovascular or surgical means; (iii) at least intraopera-

tive and/or early extractable results. Patients with previous

open or endovascular repair of aorto-iliac aneurysms, who

subsequently developed IIIAA were considered. Exclusion

criteria were: (i) internal IAA with concomitant AAA and/or

ipsilateral common or external IAA; (ii) IIIAA with conco-

mitant contralateral common or external IAA if treated

simultaneously; (iii) experimental studies; (iv) IIIAA of

etiology other than atherosclerotic/degenerative, such as

post-traumatic, post-dissection, infection, or connective tis-

sue disease; (v) development (or growth) of IIIAA after

previous endovascular aortic repair with coverage of the

origin of the hypogastric artery.

In case of papers originated from the same database, we

considered only the newest for data extraction.

Data Extraction, Outcome Measures and Evaluation of Study Quality

Two authors independently undertaken data extraction and

evaluation of study quality (PP and either CBM, EM, AU,

GR or MF). Controversies were managed by a third author

(AF), who did not take part in the abovementioned process.

Extracted data were: study design (type of study, publication

type, retrospective/prospective data analysis, type of treatment,

presence of group comparison), population characteristics

(number of patients, number of IIIAA, time frame of the study,

follow-up length, symptoms and urgency of treatment), base-

line demographics (age, gender), early and late related compli-

cations and reinterventions. Non-deducible data were labeled

as “not reported” or “non extractable,” as appropriate. Study

quality evaluation was performed with the “Newcastle-Ottawa

(NO) scoring tool.”7 Results were analyzed when provided by

at least 2 included documents.

Main outcomes were selected prior to the extraction phase:

1. Technical success (TS);

2. Early mortality;

3. Buttock claudication (BC);

4. IIIAA thrombosis/exclusion maintained during reported

follow-up.

We considered the followings as secondary outcomes:

1. Number of urgent treatments;

2. Intervention-related early and late complications;

3. Early and late reinterventions;

4. IIIAA related death.

Definition

Isolated IAA is defined as a dilatation of common, internal or

external iliac arteries, or various combination of them, without

the involvement of infrarenal abdominal aorta.1 IIIAA is

defined as a dilatation of the hypogastric artery alone (Type

II, Reber Classification8). According to the latest guidelines,1

the threshold for IIIAA definition could be set at 8 mm. TS was

defined as successful exclusion, or complete thrombosis of the

aneurysm, without residual perfusion on completion imaging,

and without major related complications. In particular, acute

limb ischemia, intraoperative conversion to open repair (in case

of endovascular treatment), or intraoperative deaths were con-

sidered treatment failures.

Statistical Analysis

Data were tabulated into a Microsoft Excel spreadsheet (Micro-

soft Corporation, Redmond, Wash, USA). The meta-analysis

was carried out with OpenMeta[Analyst] software.9 A separate

variable synthesis was performed for each drafted outcome.

Continuous data were reported as weighted means (+ 95% Confidence Interval (CI)). Mean + standard deviation (SD)

was estimated for articles providing the median, range and size

of the population.10 For proportion meta-analysis we adopted

the Freeman-Tuckey transformed proportion (double arcsine

proportion), with random effects model (DerSimonian-Laird

method). Dichotomous data are reported as percentages and

Perini et al 255

95% CI. Heterogeneity was tested with Cochrane’s Q (report-

ing the P) and I.2

Results

Paper Search and Selection Process

The first search identified 298 specific articles. Two hundred and

7 were reviewed in full-text. Most of the papers regarding IIIAA

treatment were found to be case report or small case series (164

articles), and were therefore excluded. Eventually, 13 articles

(all English papers) were included in the systematic review and

meta-analysis.11-23 The selection process is shown in Figure 1.

Finally, 192 patients with 202 IIIAA were analyzed. No

study reported comparative data, hence a 2 groups variable

synthesis meta-analysis was not feasible.

Study Design and Baseline Characteristics

Analyzed papers were retrospective. Two studies arose from a

multicenter experience (2 centers for each paper).11,14 One

paper presented 2 different groups of patients, both eligible for

Figure 1. PRISMA Flow Diagram showing the identification process of included studies. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analysis.

256 Vascular and Endovascular Surgery 55(3)

inclusion, as separate data; thus, we considered these 2 groups

as separate series during meta-analysis.21 NO score range was

5–6, with median of 6 (Supplementary Table I).

Estimated mean age was 74.68 years (95% CI 72.04-77.33; I2

82.73%, P < .001). Male sex represented the 90.2% of the

population (95% CI 85.6-94.7; I2 0%, P¼ .672). Weighted mean

IIIAA diameter was 46.28 mm (95% CI 39.72-52.85; I2 88.85%,

P < .001; Figure 2). IIIAA were estimated to be bilateral in the

11.4% (95% CI 4.9-17.8; I2 49%, P ¼ .028) of the patients.

IIIAA were symptomatic in the 18.1% of the cases (95% CI

9.3-26.9; I2 54.46%, P ¼ .019). Rupture rate was estimated in

12.6% (95% CI 5.8-19.5; I2 24.99%, P ¼ .221). Besides rup-

ture, symptoms resulting from compression of the urinary tract

(such as hydronephrosis or lumbar pain) or of the bowel were

also reported, and occurred with an estimated proportion of

7.1% (95% CI 2.7-11.5; I2 0%, P ¼ .656).

The presence of contralateral hypogastric occlusion was

reported (or extractable) in 6 papers: estimated proportion was

11.6% (95% CI 2-21.1; I2 46.46%, P ¼ .096).12,13,15,17,21,22

Data on previous aortoiliac repairs were extractable in 7

papers.12,14,16,18,21-23 Estimated proportion of previous surgical

or endovascular aortic repairs was 49.5% (95% CI 27.1-71.9; I2

80.55%, P < .001).

The indication for IIIAA repair was specified in 5 papers: each

of these papers gave a threshold diameter of 30mm.11,13,14,16,17

Muradi et al. specified they repaired also rapid growing IIIAA, if a

5 mm enlargement occurred over 6 months.16 Symptomatic

IIIAA were treated regardless of their diameter.

All studies included in this meta-analysis are listed and

summarized in Table 1.

Treatment Modalities

The most commonly performed treatment was endovascular

repair; in fact, only 2 articles reported open surgical treatment

upon 21/202 cases.11,21 Open repair included 16/21 surgical

resections or aneurysmorraphy, 4/21 proximal ligations, and

1/21 distal revascularizations. The most commonly performed

endovascular treatment was embolization with coils or vascular

plugs (81/181 reported cases), followed by embolization asso-

ciated with a stent-graft in the iliac axis (79/181), occlusion of

the origin of the internal iliac artery by deployment of a cov-

ered stent alone (15/181), and 6/181 cases of exclusion of the

IIIAA by deployment of a covered stent from the hypogastric

artery to the superior gluteal artery (SGA).

Overall, IIA was occluded in 195/202 cases. Hypogastric

artery flow preservation was reported in 7/202 cases: one case

of surgical distal revascularization, and 6 cases of SGA revas-

cularization through Viabahn (W. L. Gore & Associates, Flag-

staff, AZ, USA) deployment in the hypogastric artery to

exclude the aneurysm.12,21

Urgent procedures were carried out in an estimated

proportion of 10.4% of the cases (95% CI 4.2-16.6; I2 41.5%,

P ¼ .081).

Overall weighted mean operative time was 105.08 min (95% CI 92.06-118.11; I2 49.78%, P ¼ .093; this information was

extractable in 4 articles).11-13,15 Operative time for open proce-

dures was reported only by Yang et al., and it was 222 + 32 min.

Weighted mean operative time for endovascular procedures was

98.04 min (95% CI 82.16-113.92; I2 83.78%, P < .001).11-13,15

The volume of injected contrast agent during the endovascular

repair was reported in 2 articles; its weighted mean was 126.9

mL (95% CI 110.88-142.91; I2 47.54%, P ¼ .167).13,14

Technical Success

Overall estimated TS rate was 91.6% (95% CI 86.8-96.5; I2

45.82%, P ¼ .031; Figure 3). Weighted TS rate was higher for

open procedures (94.5%-95% CI 85.3-100; I2 0%, P¼ .907; 21

patients available for analysis), than endovascular repairs

(89.7%-95% CI 83.8-95.6; I2 55.43%, P ¼ .006; 181 patients

available for analysis). Due to the low number of studies with

Figure 2. Weighted mean diameter of isolated internal iliac artery aneurysms undergoing treatment (forest plot). CI, Confidence Interval.

Perini et al 257

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258

extractable data, a subgroup analysis for different endovascular

treatments was not carried out.

Reported intraoperative complications were: 1 coil migra-

tion (retrieved with a snare),11 1 bleeding at the percutaneous

access site,15 and 5 large vessels injury during open repair (4

iliac veins, 1 CIA, resulting in massive hemorrhages in 2

cases).21

Early Results

Thirty-day mortality was estimated to occur in the 3.1% (95% CI

0.8-5.4) of the cases, without significant heterogeneity (I2 0%,

P ¼ .969). Estimated 30-day mortality after any endovascular

repair was 2.8% (95% CI 0.5-5.1; I2 0%, P ¼ .994); after open

repair it was 8.2% (95% CI 3.4-19.8; I2 0%, P ¼ .545).11,21

BC was detailed in 10 studies (158 patients available for

analysis).11-14,16-20,23 Its postoperative incidence was estimated

in 13.9% (95% CI 8.7-19.2; I2 0%, P ¼ .622). The great major-

ity of these BC resolved or improved during follow-up (21/26

reported patients). Regarding the sole paper with pelvis blood

flow preservation (hypogastric artery endograft for SGA perfu-

sion), the reported incidence of BC was 0% (0/6 patients).12

Erectile dysfunction was not evaluated in any included

studies.

Length of stay (LOS) data were extractable in 6 studies (91

patients available for analysis).11-15,18 Overall weighted mean

LOS was 3.97 days (95% CI 1.96-5.98; I2 98.21%, P < .001).

Regarding open repair, LOS was reported only in the paper by

Yang et al. (13.2 days + 2.9 SD).11

Besides BC, other reported treatment-related early compli-

cations included: 1 readmission for hematoma at the access site

(requiring blood transfusion),15 1 type I endoleak (the patient

refused repair),17 and 1 visceral ischemia (necrosis of the blad-

der requiring resection and bilateral ureterostomy).21

Mid-Term Outcomes (Table 2)

Data on follow-up length were extractable from 8 included

studies (141 patients).11-14,16,18,21,23 Estimated mean follow-

up after IIIAA treatment was 32.63 months (95% CI 21.74-

43.53; I2 94.45%, P < .001). Aneurysm sac shrinkage after

endovascular repair occurred in the 21% of the cases (95% CI 9.6-32.4; 7 papers with extractable data, 94 IIIAA), with

moderate heterogeneity (I2 47.78%; P ¼ .074).12-14,16,18,20,22

On the other hand, sac growth was reported with an estimated

proportion of 6% (95% CI 2.3-9.7), with non-important hetero-

geneity (I2 0%; P ¼ .913), among the 9 papers with extractable

outcomes (147 IIIAA available for analysis).11-16,18,20,22

Overall, IIIAA exclusion (defined as the absence of endo-

leak on imaging) was maintained during follow-up in an esti-

mated proportion of 92.8% (95% CI 89.3-96.2; I2 0%, P ¼ .797). Complete sealing maintenance during follow-up was

reported in all cases of open repair.11,21

Reported mid-term complications were mainly endoleaks.

Yang et al. reported, in their series of 43 IIIAA, 6 endoleaks of

which 5 required reintervention.11 Chemelli et al. reported 2

type I endoleak, and 1 reperfusion of the aneurysm sac, all

requiring reintervention.17 The 2 early type II endoleak

reported by Haslam et al. resolved spontaneously at 1 and 2

years follow-up.18 Boules et al. reported 2 type II endoleak, of

which only 1 was treated.20

Reported reinterventions (28 in total) were mainly related to

endoleak correction. Chemelli et al. reported the need for bal-

loon angioplasty of a contralateral hypogastric artery for but-

tock claudication in 2 patients, and one open conversion for

stentgraft infection.17 Two other cases of open conversion were

reported by Soury et al.21

Soury et al. reported 2 related deaths during follow-up, both

after open repair: the first was due to a prosthetic infection, the

Figure 3. General estimated proportion of technical success (forest plot). CI, Confidence Interval; Ev, Events; Trt, Treated patients.

Perini et al 259

latter occurred after 18 months from open repair (the post-

operative period was complicated by visceral ischemia).21

No other papers reported related deaths occurring during

follow-up.

Excluded Noteworthy Case Reports

The great majority of the papers on IIIAA found in literature,

are represented by case reports and very small case series,

which were not included in the qualitative nor quantitative

synthesis (164 articles excluded during selection process,

basing on full-text assessment). However, some excluded

papers may have addressed noteworthy treatments, as well as

particular symptomatology, which were not considered by

included papers.

Additional remarkable treatment modalities and techniques

which may be found in case reports or small case series are:

� retrograde trans-gluteal approach for embolization24-26

� parallel stent-graft technique for IIIAA exclusion27,28

� deployment of an iliac branch device to exclude the

hypogastric aneurysm29-32

� endovascular exclusion exploiting the distal branches of

the hypogastric artery as landing zones33

Excluded noteworthy papers regarding clinical presenta-

tion—besides what we described in our qualitative synth-

esis—included:

� ureterohydronephrosis, ureteral rupture or haematuria34-37

� sciatic pain38

� arteriovenous fistula39,40

� deep venous thrombosis and pulmonary embolism41

� ileus, or bowel obstruction42,43

� aortoenteric fistula44,45

Discussion

IIIAA are a rare entity, and represent less than 0.5% of all

intra-abdominal aneurysms.3 The incidence of isolated iliac

artery aneurysm is reported to be less than 0.1% in the whole

population; most of these are aneurysm of the CIA and only

the 20% of this small subgroup involves the internal iliac

artery.2,4 Frequently, these aneurysms are multiple (involving

common and internal iliac artery at the same time).46 We

analyzed only studies regarding isolated hypogastric artery

aneurysms and their real incidence is not clear yet. In fact,

the great majority of papers we found in our literature

research were case reports or very small case series. Finally,

we included in our systematic review and meta-analysis 13

papers with a total of 192 patients and 202 IIIAA. However,

due to the widespread and increasing use of CTA, the detec-

tion of this kind of aneurysms is likely to rise in the future. As

a matter of fact, the largest case series we included in this

study were published after 2010. Even though IIIAA represent

a current issue, there is low evidence for recommending a

specific treatment modality. Our goal was to synthesize out-

comes of different repairs for IIIAA.

Table 2. Mid-Term Outcomes.

Study Year N

(patients)

N (internal iliac

arteries) Mean follow-up

(month) Sac shrinkage (n. of cases)

Sac growth (n. of cases)

IIIAA exclusion (n. of cases)

Yang 2020 42 43 56 (6-120) NR 5 35 Domoto 2019 6 6 13.0 + 3.5 2 0 6 Pirvu 2017 20 20 24 (12-96) 5 0 20 Bianchini

Massoni 2017 6 7 41.08 + 16.39 2 0 7

George 2016 8 10 1 NR 0 10 Muradi 2014 33 35 29.1 (1.2-92.8) 11 3 32 Chemelli 2010 20 20 NE NR NR 15 Haslam 2009 5 5 24.4 (2-36) 1 0 5 Wolf 2008 10 10 NE NE NE 10 Boules 2006 9 9 NE 2 1 7 Soury

(group 2) 2001 12 14 38.7 (6.9-146) NR NR 13

Soury (group 3)

2001 5 5 26.1 (18.1-50.9) NR NR 4

Melki 2001 11 12 NE 0 0 11 Mori 1999 5 6 14.92 + 10.43 NR NR 6 Total 192 202 Estimate 32.63 months

(95%CI 21.74-43.53; I2 94.45%)

Estimate 21% (95% CI 9.6-32.4; I2 47.78%)

Estimate 6% (95% CI 2.3-9.7; I2 0%)

Estimate 92.8% (95% CI 89.3-96.2; I2 0%)

NE, Not Extractable; NR, Not Reported; CI, Confidence Interval. aReported as mean + SD, unless otherwise specified.

260 Vascular and Endovascular Surgery 55(3)

Patients with IIIAA are mostly men (90.2% of the popula-

tion, with not important heterogeneity), with a mean age

around 75 years. The mean IIIAA estimated diameter was

46.28 mm (95%CI 39.72-52.85). Thus, these aneurysms tend

to be large at presentation. The considerable heterogeneity

(I2 88.85%, P < .001) regarding reported diameters, may

reflect the rarity of this pathology, as well as the different

threshold for repair adopted in different vascular centers.

The contralateral internal iliac artery is often diseased. In

fact, 11.4% of IIIAA were bilateral, and the contralateral hypo-

gastric artery was occluded in the 11.6% of the patients.

A not negligible portion of the IIIAA were symptomatic at

presentation (18.1%, with moderate/substantial heterogeneity

among included studies). Urgent procedures were necessary in

the 10.4% of the cases (95%CI 4.2-16.6, with moderate hetero-

geneity). All the urgent procedures were performed for rupture

aneurysms. These findings reflect the fact that IIIAA are

located deep in the pelvis, and often remain undetected until

rupture occurs. Other symptoms may be nonspecific, and are

typically associated with large aneurysms which cause com-

pression of nearby tissues and organs, and/or fistulization.

Common presentations are urinary compressions or nonspeci-

fic lumbar pain, but deep venous thrombosis, arteriovenous

fistulae and aorto-enteric fistulae were also described.

IIIAA are frequently associated with other abdominal aneur-

ysms. In our study, the proportion of previous surgical or endo-

vascular aortic repair was estimated in about 50% of the

population.

Currently, solid data regarding the rupture risk are lacking.

The latest European guidelines1 suggest a 35 mm threshold for

elective treatment of isolated IAA. No distinction is made

between common, internal or external iliac artery aneurysm.

Thus, available guidelines suggest to individualize the thresh-

old for repair.1 Conservative management seems appropriate in

the majority of patients with an IAA <3.5cm.1,47 However,

most of these studies concerned the natural history of CIA

aneurysms. The internal iliac artery has a considerably smaller

diameter than CIA; in fact, an internal iliac artery is considered

aneurysm when its diameter exceeds 8 mm, while a common

iliac c artery when the diameter is �18 mm.48,49 In our sys-

tematic review, only 5 papers out of 13 gave a threshold for

repair.11,13,14,16,17 The maximum diameter was set at 30 mm in

these papers; Muradi et al. indicated repair also for fast-

growing aneurysms (>5 mm in 6 months).16 Conservative

treatment may be justified until a diameter of 40 in elderly

men, while a smaller diameter can be considered for younger

patients and while treating concomitant aorto-iliac

aneurysms.48,49

The surgical treatment is rarely reported in literature (21/

202 IIIAA in this meta-analysis).11,21 In fact, open repair may

be technically challenging, and did not demonstrate any real

advantage over endovascular repair in our analysis (distal

revascularization was reported only in 1/21 case). IIIAA are

generally occluded with plugs and/or coils (160/181). Emboli-

zation is frequently followed by the occlusion of the internal

iliac artery by stent-graft deployment, especially for cases with

a large proximal IIIAA neck (79/181). The simple coverage of

the hypogastric artery is seldom reported (15/181 IIIAA), since

this technique may expose to type 2 endoleaks and aneurysm

growth; the treatment of an excluded IIIAA may be technically

challenging.24 Hybrid approach (endovascular and open) for

IIIAA is reported literature.50 Considering the papers included

in the study, surgery was not described after 2001, with the

exception of Yang’s large case series.12 Furthermore, the first

endovascular treatments described the use of coils without

stentgraft deployment. Thus, the IIIAA treatment seems to be

evolved over time. The sacrifice of the internal iliac artery,

especially if bilateral, increases the risk of ischemic complica-

tion, such as spinal cord ischemia or bowel ischemia. These

complications are rare while the onset of gluteal claudication

and erectile dysfunction can occur up to 35% and 24% of cases

respectively, according to literature.27 For these reasons, guide-

lines recommend preserving blood flow to at least one internal

iliac artery, especially in case of previous aortic surgery.1 Even

though buttock claudication and erectile dysfunction may

occur frequently after internal iliac artery sacrifice, flow pre-

servation techniques for IIIAA repair are reported only in 7/202

cases.49 In fact, suitable proximal and distal necks for stent-

graft deployment may not be available.11 In selected cases, the

proximal neck may be obtained by using an iliac branch device

(IBD) or a parallel graft technique.27-31 Regarding the distal

neck, it is sometimes possible to use the distal branches of the

hypogastric artery as a landing zone, thus sacrificing only

minor branches with good results.12,33 No IBD were used by

authors of the papers included in this review. This new and

innovative technique has been described only in some case

reports that were excluded from the study.29,30,31,33 Parallel

stent graft technique consists of the simultaneous release of 2

parallel covered stent in the external and internal iliac

arteries.27 Garrido Espeja et al. described a sandwich technique

to create a neo-bifurcation of the internal iliac artery and pre-

serve distal blood flow.28 Parallel stent graft technique could be

useful when the saving of one hypogastric artery is needed and

IBD cannot be used.

TS rates were generally good. Open repair offered

a higher TS rate than endovascular repair (94.5% vs.

89.7%); on the other hand, endovascular repair offered lower

30-day mortality rate (2.8% vs. 8.2%), and shorter LOS. BC is

a common complication after IIIAA treatment, with an esti-

mated postoperative proportion of 13.9%. However, this com-

plication is frequently transient (21 out of 26 cases resolved

spontaneously).

Mid-term outcomes were generally good. Even though

aneurysm shrinkage occurs only in 21% of the cases, IIIAA

exclusion was maintained in the 92.8% of the cases in our

synthesis (95%CI 89.3-96.2, with nonimportant heterogeneity).

IIIAA continued to grow in the 6% of the cases. Aneurysm sac

growth was generally associated with type 2 endoleaks, and

were generally treated by endovascular means. There are many

options to treat these endoleaks such as sac embolization with

trans sealing approach or gluteal arteries embolization with

standard trans-femoral or brachial approach. To correct these

Perini et al 261

endoleaks, a trans-gluteal approach was also reported in liter-

ature with percutaneous direct puncture of aneurysm sac or of

superior gluteal artery under fluoroscopy or CT-guided.24-26,51

Open conversion after endovascular treatment of IIIAA is

anecdotal.17,21 IIIAA-related deaths are rare during follow-up

(2 reported events after open conversion).21

Limitations

This systematic review and meta-analysis has some limitations.

We identified no papers which compared different treatments

for IIIAAr. Hence, we could not carry out a comparative meta-

analysis. Then, all studies were retrospective, and all but 2

arose from a single center experience. Third, the great majority

of reported experiences about IIIAA treatment were case

reports or provided small cohorts, and were therefore excluded.

However, this reflects the rarity of this pathology. Fourth, erec-

tile dysfunction was not evaluated as well as gluteal necrosis,

spinal cord ischemia and colon ischemia. Even though erectile

dysfunction seems to occur in more than 10% of males after

internal iliac artery sacrifice, included studies did not evaluate

this aspect.49 Fifth, it was not possible to distinguish between

urgent or elective treatment in terms of procedure type and

outcomes. In conclusion, further studies which compare differ-

ent approaches for IIIAA repair are needed to identify the best

operative strategy for this challenging pathology.

Conclusions

IIIAA is an uncommon intra-abdominal aneurysm. It is typi-

cally large (46.28 mm), and often symptomatic at presentation

(18.1%). Regarding asymptomatic IIIAA, the threshold for

repair should be tailored to the patient; nevertheless, a diameter

>30-35 mm is generally considered for repair in literature.

The endovascular treatment, which generally consist in

embolization with or without iliac axis stent-grafting, is the

favorite method of treatment in literature, since it offers good

short- to mid-term outcomes, avoiding the higher complication

rates and the challenges of an open surgical treatment.

Whenever feasible, flow perfusion to the hypogastric artery

or its branches should be maintained, to avoid complications

such as BC (13.9%).

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to

the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, author-

ship, and/or publication of this article.

ORCID iDs

Paolo Perini https://orcid.org/0000-0003-4554-416X

Mara Fanelli https://orcid.org/0000-0002-2890-4066

Giulia Rossi https://orcid.org/0000-0002-2558-1441

Claudio Bianchini Massoni https://orcid.org/0000-0003-1953-8073

Supplemental Material

Supplemental material for this article is available online.

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264 Vascular and Endovascular Surgery 55(3)

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