Diagnostic Approach and Management of Iliac Artery Endofibrosis in Athletes: A Scoping Review

Abstract

Iliac artery endofibrosis (IAE) is a rare vascular condition with an estimated global prevalence of 0.01%. It primarily affects endurance athletes, especially cyclists, and often presents with exercise-induced leg discomfort or reduced performance. This scoping review provides a comprehensive overview of IAE in athletes, with a focus on the current understanding of IAE, diagnostic approaches, and treatment strategies. A total of 43 studies published between 1997 and 2023 were analyzed, including 443 athletes diagnosed with IAE. Most participants were male endurance cyclists, with a predominance of left-sided lesions. The diagnostic tools primarily included ankle-brachial index measurement (used in approximately 84% of studies), Doppler ultrasonography, and angiography. Balloon angioplasty and stenting were associated with a higher likelihood of symptom relapse and often required secondary interventions. In contrast, endarterectomy with patch angioplasty remains the preferred treatment for athletes who continue to participate in competitive sports because of its high success rate, long-term durability, and sustained symptom relief.

INTRODUCTION

Iliac artery endofibrosis (IAE) is characterized by intimal thickening of the iliac artery wall, leading to narrowing of the arterial lumen [1]. IAE is relatively rare, mostly affecting athletes and highly active individuals younger than 40 years [1]. This pathological process is believed to result from repeated mechanical stress on the iliac arteries during high-intensity physical activities, especially in athletes. The intimal thickening is often accompanied by fibrosis, which ultimately reduces blood flow and causes exercise-induced ischemia. Although the true prevalence of this condition remains unknown, it is thought to be very low, possibly <0.01% [2]. Owing to the supposedly healthy lifestyle of these athletes, vascular disease and atherosclerosis are unexpected, and arterial insufficiency is often missed.

The clinical manifestations of IAE vary widely, ranging from mild intermittent claudication to severe ischemia. Patients may also present with nonspecific symptoms, such as leg pain, numbness, or tingling, which are often mistaken for sports-related musculoskeletal injuries [3]. These symptoms often subside at rest, further complicating diagnosis [3]. The nonspecific nature of the presentation, along with the nature to perform clinical examinations in resting state, can lead to diagnostic delays or misdiagnosis.

Currently, the diagnosis of IAE relies on a combination of clinical evaluation and noninvasive tests, such as Doppler ultrasonography or ankle-brachial index (ABI) measurement, to assess the presence of arterial narrowing. Management approaches vary depending on the disease severity, ranging from conservative measures to surgical interventions, including endofibrosectomy in more advanced cases.

A systematic review published in 2012 summarized the etiology, diagnosis, and management of endofibrosis and iliac artery kinking [4]. More recently, a Delphi consensus study by Hinchliffe et al. [5] surveyed expert clinicians regarding their current practices and perceptions of this condition. While informative, this study was limited to capturing prevailing opinions rather than evaluating the evidence base. In 2024, Scuto et al. [6] compiled published cases related to external IAE; however, their review was limited to the diagnostic accuracy and treatment outcomes.

The current scoping review aims to provide a comprehensive overview of IAE, emphasizing recent advances in the understanding of its clinical presentation, diagnostic challenges, and evolving treatment modalities.

MATERIALS AND METHODS

1) Protocol and registration

Our protocol was drafted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines [7]. The protocol was registered in the Open Science Framework under the title “Diagnostic approach and management of iliac artery endofibrosis in athletes: a scoping review” [8]. This scoping review followed the PRISMA extension for Scoping Reviews (PRISMA-ScR) checklist [7]. This review does not fall under the category of human subject research and, therefore, does not require approval from an institutional review board.

2) Inclusion criteria

This scoping review considered all studies published in English, including case reports, case series, cohort studies, and clinical trials involving athletes diagnosed with IAE. The publication dates ranged from 1997 to 2023. Studies involving patients with only arterial kinking without endofibrosis were excluded. Studies that included participants with endofibrosis affecting arteries or veins other than the iliac arteries, without endofibrotic lesions in the iliac artery, were also excluded. Most review articles were excluded unless they reported a specific case of IAE. Cohort studies focused only on the diagnostic or interventional aspects of IAE, such as testing the efficacy of a specific diagnostic/treatment modality, were also excluded.

3) Information sources

The PubMed, ScienceDirect, and Web of Science databases were searched to identify potentially relevant documents. An initial limited search was conducted on PubMed to identify articles on the topic and determine which search terms should be used. The search terms included “iliac artery,” “endofibrosis,” “external iliac artery,” “athlete,” “runner,” “cyclist,” and “triathlete.” A database search was then performed on February 21, 2024. Controlled vocabulary such as MeSH terms was not applied (Appendix 1). Gray literature sources were excluded because the search was limited to traditional databases that prioritize peer-reviewed publications.

4) Selection of sources of evidence

The final search results were exported to Rayyan (https://www.rayyan.ai/), and duplicates were removed. Four researchers conducted two rounds of screening. In the first round, articles that did not meet the inclusion criteria based on the title and abstract were excluded. In the second round, the preliminarily included sources were fully assessed. The full text of selected sources was reviewed in detail according to the inclusion criteria to ensure that they included either reported cases or cohort studies of athletes with IAE, as well as relevant diagnostic or treatment information. Articles that did not meet the criteria were excluded, with the reasons being recorded. Each source was screened by two blinded reviewers (CK and HP), and any conflict was resolved through discussion with a third reviewer (MK) who was not involved in the screening process.

5) Data charting and extraction

A preliminary data extraction spreadsheet (Appendix 2) was developed, in which the extracted data from the included sources were recorded. The following data were extracted: the number of athletes, sex, age, affected side, sport, country of study, study design, diagnostic and/or treatment modalities, and reported outcomes. Owing to the dynamic nature of the scoping review process, the data extraction spreadsheet was continuously refined to ensure that essential information was captured comprehensively as the data extraction process progressed. The data were extracted independently by two reviewers. Discrepancies or uncertainties between the two reviewers were resolved by referring to the original source materials.

6) Synthesis of results

Tables 1 and 2 summarize the case reports/series and cohort studies separately. Fig. 1 shows the PRISMA flowchart, which visually depicts the screening process and includes the initial number of articles found, number of articles after duplicate removal, number of articles remaining after screening, and final number of articles included in the review.

Table 1.

Summary of all case reports/series included in the review

Study	No. of symptomatic athletes (limbs)a	No. of asymptomatic athletes (limbs)	Type of treatment	Diagnosis	Outcome
Carfagno et al. [3], 2023	2	2	Endarterectomy with patch angioplasty/fogarty embolectomy (n=1), iliofemoral bypass (n=1)	Physical exam, US with Doppler, XR, MRI, MRA CTA, Physical exam	No postoperative complications
Mazurová et al. [2], 2022	2	2	Thrombectomy/endofibrosectomy/venous patch from the great saphenous vein (n=1), Endofibrosectomy/venous patch from the great saphenous vein (n=1)	ABI, Doppler sonography, CTA ABI, CDU, CTA	No postoperative complications
Verma et al. [25], 2022	1	1	Conservative treatment	Clinical examination, ABI, US Doppler, Non-contrast QISS, MRA	No postoperative complications
Bilman et al. [19], 2021	1	1	Endarterectomy	MRI, ABI was normal, US doppler, 2D US, CTA	No postoperative complications
Parimi et al. [26], 2020	1	1	Endarterectomy with patch angioplasty	Physical exam, ABI, MRA, Duplex ultrasound	No postoperative complications
Cai et al. [27], 2019	1	1	Endarterectomy with vein patch repair with ipsilateral great saphenous vein	ABI, MRA	Presented with similar symptoms on the right side after a year and managed in a similar manner
Lindo et al. [20], 2019	1	1	Endarterectomy and patch angioplasty	ABI, CTA, Duplex US	No postoperative complications
Wuarin et al. [41], 2019	1	1	Endarterectomy and patch angioplasty, early recurrence due to intimal hyperplasia after 6 weeks, with symptoms appearing worse than before surgery, and secondary drug-eluting balloon angioplasty performed	MRI, Duplex examination, Exercise test	Initial surgery led to intimal hyperplasia. Results of post-angioplasty were positive. Slight numbness of the thigh at max effort, but did not prevent the patient from competing
Sullivan et al. [23], 2019	2	0	EIA reconstruction using the ipsilateral great saphenous vein	ABI, CTA	No postoperative complications
Peake et al. [40], 2018	56	36	EIA Endarterectomy and patch angioplasty (n=13), EIA/CFA endarterectomy and patch angioplasty (n=9), CIA/EIA/CFA patch angioplasty (n=1), extension of EIA patch to CFA (n=1), CFA patch angioplasty/PFA endarterectomy (n=1), CIA to CFA bypass (n=1)	ABPI, Ultrasound sonography, Angiogram, DSA, CTA	No postoperative complications (n=23), non-resolution of symptoms (n=1), return of pre-operative symptoms (n=3)
Franco et al. [24], 2016	1	1	Patch angioplasty with resection and correction of the redundancy of the left external iliac artery	ABI, CTA	No postoperative complications
Campbell et al. |[21], 2016	1	1	Iliac replacement with a reversed saphenous interposition graft via a retroperitoneal approach	Physical examination, ABI, Doppler imaging, MRA, Diagnostic angiogram	No postoperative complications
Brunelle et al. [1], 2016	2 (Left initially, then right)	0	Iliac artery repair with shortening of the artery and a vein patch	Bloodwork, abdominal ultrasound, echocardiogram, treadmill stress test, upper gastrointestinal endoscopy, CTA, MRA	No postoperative complications, developed similar symptoms in the right lower extremity, and underwent bilateral iliac artery endofibrosis
Veraldi et al. [42], 2015	2	2	Case 1: Angioplasty of the EIA with a 10-mm diameter non-compliant balloon (no improvement), endofibrosectomy with autologous great saphenous vein patch Case 2: Balloon angioplasty/laparoscopic debridement of EIA from left psoas muscle (immediate recurrence of symptoms), endofibrosectomy of the first tract of EIA, and autologous great saphenous vein closure patch	Case 1: ABI, Angio-CT Case 2: CT	No postoperative complications
Lindner et al. [43], 2014	1	1	Conservative treatment, removal of endofibrotic lesion, and artery shortening with autologous vein patch	Physical examination, Blood examinations, CTA	No postoperative complications
van Rensburg et al. [45], 2014	2 (Right initially, then both)	0	Bilateral prosthetic graft bypass	Lumbar MRI, resting duplex Doppler US, CTA ankle pressure, color duplex Doppler	No postoperative complications
Green et al. [44], 2014	1	1	Endarterectomy and vein patch angioplasty	Patient history, nerve studies, spinal MRI, duplex ultrasound, MRA	No postoperative complications
Howard et al. [22], 2013	1	1	Endoscopic great saphenous vein harvest, total laparoscopic exploration, endarterectomy, and vein patch	Physical exam, duplex ultrasound, ABI, diagnostic angiogram	No postoperative complications
Falor et al. [46], 2013	3	1	Case 1: Bilateral common iliac to common femoral bypass with 8-mm Dacron grafts Case 2: Transabdominal lower midline common iliac to common femoral artery bypass with 8-mm Dacron graft	Case 1: Physical examination, ABI Case 2: ABI, CTA	No postoperative complications
Bucci et al. [28], 2011	1	1	Surgical resection with autologous vein interposition	Clinical examination, Doppler US, CTA, ABPI	No postoperative complications
Willson et al. [29], 2010	1	1	Open repair of dissection with an interposition graft	Physical examination, resting Doppler examination, ABI, CTA	No postoperative complications
Getzin and Silberman [30], 2010	1	1	Patch angioplasty	Physical exam, MRI, ABI, exercise test, angiography	No postoperative complications
Maree et al. [31], 2007	1	1	Endarterectomy with balloon angioplasty and stent deployment	Exercise test, ABI, duplex ultrasonography, MRA, arteriography	No postoperative complications
Giannoukas et al. [47], 2006	2	2	Case 1: Balloon angioplasty Case 2: Conservative treatment	Case 1: ABI, MRA, intra-arterial DSA Case 2: ABPI, duplex scan after exercise, MRA, intra-arterial digital subtraction	No postoperative complications
Scavèe et al. [32], 2003	1	1	Fibrosis removal and iliofemoral vascular bypass graft	Clinical examination, ABI, Doppler scan, CT	No postoperative complications
Ford et al. [33], 2003	1	1	Percutaneous transluminal balloon angioplasty	Physical examination, ABPI at rest, intra-arterial DSA of the right leg	No postoperative complications
Wijesinghe et al. [34], 2001	1	1	Balloon angioplasty with a 7×4 mm balloon inflated to 10 atmospheres for one minute	ABPI, arterial duplex scan, intra-arterial DSA	Symptoms returned after 6 weeks; the patient considered definitive surgical treatment
Speedy et al. [35], 2000	1	1	Iliac partial endarterectomy and long vein patch angioplasty with shortening of the external iliac artery	Exercise test, AAI, leg arteriogram, ultrasound examination	No postoperative complications
Abraham et al. [36], 1999	1	1	Shortening the artery, resection of the fibrotic lesions, and enlargement of the artery with a saphenous vein patch	Clinical exam, ABPI, exercise test, ultrasound imaging, arteriography	No postoperative complications
Abraham et al. [37], 1997	1	1	Iliofemoral bypass with enlarged saphenous vein	ABI, exercise test, US, arteriography	No postoperative complications
Wright et al. [38], 1997	1	1	Prescribed course of vasodilators	Clinical examination, MRI, resting Doppler, ABPI	Discontinued medication because of headaches

AAI, ankle-arm index; ABI, ankle-brachial index; ABPI, ankle-brachial pressure index; CDU, color Doppler ultrasonography; CT, computed tomography; CTA, computed tomography angiography; DSA, digital subtraction angiography; MRI, magnetic resonance imaging; MRA, magnetic resonance angiography; QISS, quiescent-interval single-shot; US, ultrasound; XR, X-ray.

^aNumber of symptomatic limbs refers to those with a confirmed diagnosis regardless of whether surgery was performed.

Table 2.

Summary of all cohort studies/clinical trials included in the review

Study	Study design	Treatment/diagnosis or both	No. of symptomatic athletes (limbs)	No. of asymptomatic athletes (limbs)	Type of operation	Diagnosis
van Hooff et al. [11], 2023	Retrospective cohort	Both	79	57	Iliac endarterectomy with autologous patching	Patient history, physical examination, duplex ultrasound examination, Incremental maximal cycling exercise test, AABI
Tran et al. [9], 2021	Retrospective cohort	Diagnosis	23	19	Bovine patch angioplasty of external iliac artery (n=17), interposition bypass grafting for iliac occlusion (n=4)	ABI, CTA, BART
Perrier et al. [12], 2020	Prospective cohort	Diagnosis	33	31	Operation confirmed endofibrosis (n=33)	DSA, CTA, ECG-gated CTA, ABPI
Kleinloog et al. [39], 2019	Clinical Trial	Diagnosis	45	95	NA	Pedal power measurement (PPM), echo-Doppler, exercise test
D’Abate et al. [10], 2017	Clinical trial	Diagnosis	29	45	Endarterectomy	CDU, ABPI, histology
Shalhub et al. [13], 2013	Retrospective cohort	Both	10	6	Great saphenous vein patch angioplasty	Exercise treadmill test, ABI, duplex ultrasound
Bender et al. [14], 2012	Retrospective cohort	Both	37	35	Endarterectomy and vein patch	Patient history, physical examination, cycling test, ABI, echo-Doppler examination
Politano et al. [48], 2012	Cohort study	Treatment	31	19	Patch angioplasty of external iliac artery with or without endarterectomy (n=26), placement of interposition graft (n=5), isolated inguinal ligament release (n=1)	NA
Alimi et al. [15], 2004	Retrospective cohort	Both	14	12	NA	US, DSA, ABI
Fernández-García et al. [16], 2002	Clinical Trial	Diagnosis	7	29	NA	AAI, exercise test, leg pressures, humeral pressures
Taylor and George [17], 2001	Clinical Trial	Diagnosis	12	32	NA	ABPI, resting blood pressure
Abraham et al. [18], 2001	Clinical trial	Diagnosis	78	394	NA	ABI, ankle pressure, ASBP, ABI

AAI, ankle-arm index; ABI, ankle-brachial index; ABPI, ankle-brachial pressure index; ASBP, ankle systolic blood pressure; BART, bicycle exercise ankle-brachial index recovery time; CDU, color Doppler ultrasonography; CTA, computed tomography angiography; DSA, digital subtraction angiography; ECG, electrocardiogram; NA, not available; US, ultrasound.

Fig. 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart. This flowchart is adapted for scoping review and illustrates the full scoping review process from initial search to abstract screening and full-text assessment.

RESULTS

The systematic search yielded 363 records—359 from the databases and 4 from the manual search of references in the included papers. Subsequently, book chapters, conference abstracts, correspondence, editorials, and discussions were removed, resulting in 154 articles. After removing duplicates, 110 titles and abstracts were screened. Of these, 61 were excluded for one of three reasons: wrong publication type (review article with no case study), wrong population (non-athletes), or wrong condition (not specifically endofibrosis of the external iliac artery). The full texts of the remaining 49 articles were assessed for eligibility. A total of 43 papers met the predetermined criteria and were analyzed (Fig. 1).

In the case reports and case series (Table 1), which included 81 athletes, most were male (62%) and 38% were female. The mean patient age was 37 years (range, 18-52 years). Left-sided IAE was more common, affecting 54% of cases, followed by right-sided (30%) and bilateral endofibrosis (16%). The most frequently associated sports in the case reports were cycling (70%), followed by running (19%) and triathlon (11%). Most case reports/series included complete demographic information, with only 3% not specifying sex.

In the cohort studies (Table 2), which included 362 athletes, the sex distribution was predominantly male (69% male; 31% female). The mean age was 39 years. Similar to the case reports/series, the left side was more commonly affected: 65% left-sided, 28% right-sided, and 7% bilateral. Most affected athletes were cyclists. Approximately 16% of cohort studies lacked demographic details, such as age or laterality. Both case reports/series and cohort studies were conducted worldwide, with contributions from the USA, Europe (Switzerland, Spain, and the UK), India, and New Zealand.

The most common diagnostic techniques were exercise tests and pressure measurements, most often the ankle–brachial index (ABI). This was reported in approximately 84% of the included studies, ranging from large cohort studies [9-18] to single-patient reports [19-38]. Ultrasound (color Doppler, duplex) was the most frequently used imaging method in 50% of the cohort studies [10,11,13-15,39]. When more detailed arterial mapping was required, investigators resorted to invasive angiography (digital subtraction angiography [DSA], computed tomography angiography [CTA], or magnetic resonance angiography [MRA]).

Several nonstandard but promising diagnostic methods were also identified. Tran et al. [9] proposed a diagnostic measurement called “bicycle exercise ankle-brachial index recovery time” (BART), a test that quantifies how quickly the ABI recovers to 0.9 after exercise. A normal BART is defined as a recovery time of less than 2 minutes, whereas an abnormal BART is one in which the ABI remains below 0.9 beyond 6 minutes. An extended recovery time indicates significant arterial obstruction. This test is suggested to offer a more functional assessment than the ABI alone. Kleinloog et al. [39] described another diagnostic technique called “pedal power measurement,” which examines the differences in power output between the affected and unaffected legs during high-intensity cycling using instrumented pedals. A power asymmetry greater than 5.1% between the legs is considered abnormal. This method may be helpful in early IAE cases in which the ABI or imaging findings are inconclusive or borderline. Finally, D’Abate et al. [10] emphasized color Doppler ultrasonography as a sensitive and noninvasive diagnostic tool. They also proposed CTA as a viable alternative when DSA—the typical gold standard—is inconclusive or cannot be performed.

Operative techniques fell into four broad categories: (1) straightforward excision followed by patch angioplasty, involving direct removal of the endofibrotic segment through an open approach and subsequent patch closure [2,3,20,24,26,27,30,40]; (2) more complex or hybrid patch reconstructions, which incorporated additional arterial remodeling techniques (such as vessel shortening or laparoscopic resection) to address lesions that would not be adequately treated by simple excision alone [1,19,22,31,35,36,41-44]; (3) replacement with autologous vein or prosthetic grafts [21,23,28,29,32,37,45,46]; and (4) non-excisional approaches (balloon angioplasty or conservative treatment) [25,33,34,38,47].

The first three approaches generally resulted in uncomplicated recovery and durable symptom relief. Among the 31 case reports and series, endarterectomy with patch angioplasty was the most commonly reported surgical treatment, serving as the initial management in the majority of cases. In total, at least 21 cases involved patch angioplasty, typically performed in conjunction with endofibrosectomy. Bypass or interposition grafting was reported in approximately 9 cases, usually for long-segment or extensive disease. Balloon angioplasty was attempted in a limited number of cases (n=5), but was generally less effective and often led to symptom recurrence or subsequent surgery. Stent deployment was reported in only one case. Many studies combined techniques, most commonly performing endarterectomy with patch angioplasty, which was considered the standard approach in surgically treated athletes.

Politano et al. [48], in a cohort study focusing exclusively on IAE treatment, reported higher patient satisfaction with patch angioplasty than with interposition grafts (48% vs. 25%). Five articles (42%) from the included cohort studies and clinical trials addressed treatment techniques in addition to diagnostic methods, with van Hooff et al. [11] highlighting that iliac endarterectomy with autologous patching achieved a long-term patient satisfaction rate of over 91%. Nevertheless, this approach was associated with complications in a small proportion of patients, including restenosis, acute occlusion, and neuropathic pain (3.8%, minor morbidity; 3.8%, long-term complications) [11].

Case studies by Carfagno et al. [3] and Bilman et al. [19] reported no complications after endarterectomy with patch angioplasty. Wuarin et al. [41] pointed out the probability of early symptom recurrence due to intimal hyperplasia after endarterectomy, which required a secondary procedure using drug-coated balloon angioplasty. The patient successfully resumed competition. Despite these occasional complications, the majority of patients (90%-100%) in cohort studies/clinical trials were able to resume their previous exercise regimen, suggesting that most surgical approaches lead to successful outcomes.

1) Representative case vignette

The following vignette is based on Lindo et al. [20]:

A 48-year-old male elite cyclist presented with progressive exertional pain and weakness in the left leg, which subsided with rest. He had no history of trauma or vascular risk factors, although he had previously undergone left inguinal hernia repair. Post-exercise testing revealed a significant drop in the left ABI (0.30), which increased only to 0.7 after 10-minutes rest. Duplex ultrasonography showed the left distal external iliac artery with elevated peak systolic velocity (PSV) of 580 cm/s and endoluminal echoes consistent with intimal thickening. CTA in the cycling position also confirmed the diagnosis. The patient underwent a left external iliac to common femoral artery endarterectomy and patch angioplasty. Intraoperative findings indicated significant intimal hyperplasia without evidence of atherosclerosis. At 3-month follow-up, the patient was asymptomatic, had returned to cycling, and demonstrated significantly improved ABIs with normal duplex velocities.

DISCUSSION

This review included 43 studies, comprising a total of 443 athletes. Most were male (62%), and cycling (70%) was the most common sport associated with IAE. In our dataset, the left iliac artery was more frequently affected (54%). A range of diagnostic techniques, including exercise tests and various imaging methods, were used across the studies. Surgical treatments varied, with endarterectomy combined with patch angioplasty being the most common. While some complications such as restenosis and recurrence were reported, the majority of patients successfully returned to their previous activity levels and achieved favorable outcomes with significant symptom relief.

Previous studies have highlighted a greater risk of IAE among elite or professional cyclists aged <40 years who cycle approximately 14,500 to 20,000 kilometers yearly, accumulating around 120,000 kilometers over their careers [1,4,24]. This condition is more common in men, but lesions tend to be longer in women [24,49]. Our review aligns with these previous findings, as the mean age of athletes in the included studies was approximately 36 years, with the majority being male cyclists. The higher disease prevalence in men could be partially explained by the historical male predominance in high-intensity endurance sports [50]. In contrast, the greater lesion length in women may be attributed to anatomical differences, such as a wider pelvis, which permits greater arterial length without “kinking” and may distribute arterial stress over a longer segment [50]. Therefore, diffuse stenosis may span a more extensive segment before producing noticeable symptoms. Hormonal factors may also influence the smooth muscle or intimal response to repeated mechanical stress, although direct evidence for this has not yet been established [50].

This review identified left-sided endofibrosis as being more common than right-sided cases (54%), mirroring the review findings of Peach et al. [4] and Parks et al. [50], who reported rates of 52% and 54.1% for left-sided endofibrosis, respectively. The laterality of this condition is believed to be related to the underlying pathophysiology of IAE and the cycling position required for maximum aerodynamics. Remaining in this position for an extended period leads to chronic friction and endofibrosis [42].

Several etiological mechanisms, including hip joint hyperflexion and excessive vessel length, can increase the likelihood of IAE, resulting in arterial fixation and mechanical stress-induced fibrotic changes. Psoas muscle hypertrophy is also thought to be a contributing factor because it may exacerbate mechanical compression of the artery and promote continuous traction [42]. Additionally, endofibrosis in the left iliac artery may further worsen owing to the increasing incidence of lower lumbar degenerative scoliosis, where spine degeneration produces a more convex curve on the left side, and psoas hypertrophy tends to develop on the convex side of the curvature [20].

Histopathological examination of IAE consistently shows non-atherosclerotic arterial remodeling [2,41,42,45]. The most common finding is intimal thickening with loosely arranged connective tissue composed of collagen, elastin, and smooth muscle cells [19,31]. Unlike atherosclerosis, these lesions lack lipid deposits or calcium and rarely show signs of inflammation [2,42]. Inflammatory cells such as macrophages may be present but are not abundant [22,41]. The media and adventitia are usually unaffected, although mild fibrosis can occur [32]. In some cases, a thin fibrin thrombus was found on the surface of the lesion, typically in patients with acute symptoms [31]. Overall, IAE lesions are characterized by fibrous intimal overgrowth without atherosclerotic plaque, supporting the theory that IAE arises from repetitive mechanical stress during intense athletic activity rather than traditional vascular risk factors.

1) Diagnosis

This review found that exercise tests and pressure measurements were the most frequently performed diagnostic techniques, followed by ultrasonography and, in more selective cases, invasive imaging. A survey conducted by Hinchliffe et al. [5] showed that among experienced clinicians, the pre- and post-exercise ABI testing was considered the most appropriate method for confirming or excluding endofibrosis (Appendix 3). While the ABI alone may demonstrate high sensitivity and specificity (sometimes up to 100%), the combination of ABI and ultrasound imaging is often necessary to localize the disease [19].

Color Doppler ultrasonography has been reported to have a sensitivity of up to 85% in identifying IAE, whereas duplex ultrasound can assess anatomical abnormalities and flow changes in the affected vessels [2]. However, ultrasound is operator dependent and requires precise positioning; in addition, duplex imaging achieves high sensitivity mainly in advanced disease [21].

More invasive techniques, such as angiography, can be used to confirm positive findings or clarify equivocal results from initial tests. CTA can accurately assess the diameter and length of endofibrosis, whereas DSA is particularly useful for identifying arterial branches to the psoas muscle and for evaluating severe stenosis or occlusion [19]. MRA is useful in detecting flow abnormalities [21]. Intravascular ultrasound has shown promise as a superior diagnostic tool to traditional modalities, providing in vivo visualization of vessel wall structure, lesion morphology, and echogenic differences among arterial layers [21]. Although there have been no conclusive studies on which invasive diagnostic techniques should be prioritized, DSA has historically been suggested to be the gold standard for assessing flow-limiting arterial lesions [22]. However, more recent studies found that CTA offers moderate to good agreement with DSA for evaluating the common and external iliac arteries, suggesting CTA as a viable alternative [12].

2) Treatment

Regarding the treatment for IAE, this review revealed that endarterectomy with patch angioplasty was the most commonly performed surgical intervention. Multiple case studies focusing on this technique reported no postoperative complications, indicating that it may be associated a lower complication rate compared to other techniques [3,20,26,31,35,40,44]. In a study by van Hooff et al. [11], 97% of patients treated with endarterectomy and vein patch angioplasty returned to competitive sports, with only one case of restenosis reported after 12 months. Similarly, Bender et al. [14] noted immediate improvements in 84% of 36 athletes with the same technique, with only one case of postoperative bleeding.

In patients requiring immediate symptom relief, balloon angioplasty or stenting was occasionally performed. However, these techniques often resulted in symptom recurrence after a few weeks and were limited in effectiveness for patients who want to continue endurance training [3]. For instance, Veraldi et al. [42] reported no symptom relief after balloon angioplasty, necessitating conversion to open surgery. Similarly, Wijesinghe et al. [34] documented symptom recurrence within 6 weeks after balloon angioplasty, implying that these interventions may have poor durability.

Endovascular techniques have several limitations in treating IAEs. The fibrotic and elastic nature of affected arterial segments results in high recoil rates after balloon dilation [42]. Additionally, stents may exacerbate vessel trauma due to ongoing mechanical stress during exercise, potentially causing stent fracture, plication, or friction-related arterial injury [3,42].

Simple arterial release may be performed in patients with fibrous attachments that exacerbate arterial kinking with no intimal damage; however, this method is associated with a higher risk of recurrence [23]. As suggested by some studies, bypass procedures using autologous vein grafts are generally reserved for patients with severe, refractory symptoms and complete occlusion [3,23]. When the saphenous vein is too small (less than 3 mm), alternative conduits such as prosthetic grafts or saphenous vein panel graft can be used. Vessel shortening procedures are indicated for significant arterial elongation or kinking and are often performed as part of endarterectomy and patch angioplasty [40].

3) Management algorithm

The general diagnostic and management pathway for IAE is illustrated in Fig. 2. The following algorithm expands on the framework proposed by Peake et al. [40]. A comprehensive approach, including detailed history taking and clinical examination, is necessary for evaluating suspected IAE. Any symptoms reported during physical activity or abnormal auscultation detected during clinical examinations should prompt further noninvasive tests.

Fig. 2.

Proposed diagnostic and management algorithm for IAE. This flowchart outlines a stepwise approach, beginning with clinical suspicion based on exertional lower-limb symptoms in endurance athletes. This algorithm builds on prior protocols (Peake et al. [40]). ABI, ankle-brachial index; CTA, computed tomography angiography; DSA, digital subtraction angiography; EDV, end-diastolic velocity; EIA, external iliac artery; IAE, iliac artery endofibrosis; PSV, peak systolic velocity; US, ultrasound.

The first-line diagnostic approach involves bilateral ABI testing and duplex Doppler ultrasonography of the iliac and femoral arteries, both at rest and after exercise. A post-exercise ABI drop >0.3, PSV >350 cm/s, end-diastolic velocity >150 cm/s, and monophasic waveforms support the diagnosis [40]. If values are borderline, advanced imaging (CTA or MRA) may be needed.

Patients with high-grade stenosis and disabling symptoms, particularly those wishing to maintain competitive sports, are candidates for surgical intervention. In contrast, patients with mild or no symptoms should be managed conservatively. Peach et al. [4] and Hinchliffe et al. [5] highlighted the role of prolonged hip flexion and iliac artery elongation due to extreme cycling postures as key contributors. As such, adjusting the bike fit, such as the position of the saddle, to reduce the hip flexion angles may help mitigate these effects. Adjusting the training intensity and incorporating regular positional changes during long-distance cycling may also reduce the accumulated mechanical stress.

Patients managed conservatively should undergo annual surveillance with duplex ultrasonography and exercise ABI measurement. If symptoms worsen or follow-up imaging reveals deterioration, surgical referral should be considered. However, diagnostic thresholds and surveillance intervals are not yet standardized, and further consensus is required.

4) Limitations

This review is one of the few to explore IAE in depth based on existing literature; however, it comes with several limitations. During the inclusion phase, articles that mentioned iliac artery kinking, rather than true endofibrosis, were excluded to narrow the scope of this review. This might have inadvertently omitted relevant discussions on the topic. Another notable limitation was the exclusion of articles published in languages other than English, which introduces a risk of language bias. As a result, potentially valuable contributions from non-English sources may have been overlooked, thereby limiting the comprehensiveness and generalizability of the review.

CONCLUSION

Significant progress has been made in the diagnosis and treatment of IAE over the past four decades. When left untreated, IAE can lead to serious complications such as arterial dissection and thrombosis. This review highlights the predominance of IAE among male cyclists, with left-sided laterality being more common owing to biomechanical and anatomical factors.

Exercise testing and imaging modalities such as ABI, ultrasound, and CTA remain essential diagnostic tools, although invasive techniques may still be required in some cases. Surgical intervention, particularly endarterectomy with patch angioplasty, has demonstrated high success rates, whereas endovascular treatments such as balloon angioplasty and stenting pose risks of recurrence. Given that IAE predominantly affects youthful and physically active individuals, the development of potential preventive strategies tailored to these athletes should be prioritized.

Funding Statement

FUNDING None.