External iliac artery endofibrosis in a young cyclist

[Iliac endofibrosis in high-performance sports: an interdisciplinary diagnostic challenge]

OBJECTIVES

Iliac endofibrosis (IE) is a rare arterial disease in endurance athletes, especially cyclists and triathletes. The diagnosis is considered challenging and the latency from the onset of initial symptoms to diagnosis is often several years. Diagnostic options include determination of the ankle brachial index (ABI) after maximal exercise as a non-invasive procedure, as well as duplex sonography, CT or MRI angiography, and invasive angiography. The aim of this paper is to analyse in more detail this time lag to correct diagnosis from the first description in 1985 to the year 2021, as well as to identify the most important diagnostic tools for practice.

MATERIALS AND METHODS

Literature research according to PRISMA criteria in PubMed, Web of Science, Cochrane databases, supplemented by a search in Google Scholar up to 10/18/2021.

RESULTS

We identified a total of 133 publications that dealt thematically with IE in endurance athletes. In 42 publications (40 case reports and 2 clinical trials), the diagnosis was confirmed intraoperatively, and in 32 (32/42; 74.4%), statements were made about the duration from the onset of the first symptoms to the final diagnosis (mean 45, median 36 months). This latency was constant over the entire observation period from 1985 to 2021, with no trend toward shortening. Twenty-four papers (24/42; 56%) reported detailed results of ABI determination as well as further diagnostic testing. In all cases, the ABI value decreased to less than 0.66 (in 5 case reports, this decrease was measured at rest; in 19 case reports, it occurred after stress), whereas further diagnostic testing by duplex sonography, DSA, MRA, or CTA revealed no abnormal findings in 3 cases (3/24; 12.5%) and showed no more than minor stenosis in 14 cases (14/24; 58.3%).

CONCLUSIONS

A drop in ABI after exercise is the most reliable method to diagnose iliac endofibrosis. This non-invasive and easy-to-perform examination should be integrated into the performance diagnostics of highly ambitious endurance athletes at risk. This may ideally prevent irreversible vessel wall damage by early diagnosis as well as a reduction of the presumed high number of undetected cases.

External Iliac Artery Endofibrosis: A Discussion on Two Unique Cases

Iliac artery endofibrosis (IAE), as the name suggests, involves subintimal fibrosis of the iliac artery. IAE is most commonly associated with competitive athletics, particularly cycling, and remains a rather underappreciated diagnosis in the clinical setting. We present two unique and distinct presentations of IAE in competitive athletes. The first case involves a 38-year-old male cyclist who initially presented with complaints of a bulge at the right groin and acute onset monoplegia and paresthesia associated with exertion of the right lower extremity. This patient was referred to vascular surgery and underwent right common iliac artery and proximal common femoral artery endarterectomy with patch angioplasty and Fogarty embolectomy. Case 2 involves a 50-year-old female triathlete who presented with left lower extremity claudication of a more chronic course, with symptoms beginning approximately four years prior. The pain radiated to her upper thigh and was associated with exertion, restricting her exercise tolerance and return to training. After a diagnosis of IAE was made, she was referred to vascular surgery for a left iliofemoral bypass.

Protease-activated receptors are potential regulators in the development of arterial endofibrosis in high-performance athletes

OBJECTIVE

High-performance athletes can develop symptomatic arterial flow restriction during exercise caused by endofibrosis. The pathogenesis is poorly understood; however, coagulation enzymes, such as tissue factor (TF) and coagulation factor Xa, might contribute to the fibrotic process, which is mainly regulated through activation of protease-activated receptors (PARs). Therefore, the aim of this explorative study was to evaluate the presence of coagulation factors and PARs in endofibrotic tissue, which might be indicative of their potential role in the natural development of endofibrosis.

METHODS

External iliac arterial specimens with endofibrosis (n = 19) were collected during surgical interventions. As control, arterial segments of the external iliac artery (n = 20) were collected post mortem from individuals with no medical history of cardiovascular disease who donated their body to medical science. Arteries were paraffinized and cut in tissue sections for immunohistochemical analysis. Positive staining within lesions was determined with ImageJ software (National Institutes of Health, Bethesda, Md).

RESULTS

Endofibrotic segments contained a neointima, causing intraluminal stenosis, which was highly positive for collagen (+150%; P < .01) and elastin (+148%; P < .01) in comparison with controls. Intriguingly, endofibrosis was not limited to the intima because collagen (+213%) and elastin (+215%) were also significantly elevated in the media layer of endofibrotic segments. These findings were accompanied by significantly increased α-smooth muscle actin-positive cells, morphologically compatible with the presence of myofibroblasts. In addition, PAR1 and PAR4 and the membrane receptor TF were increased as well as coagulation factor X.

CONCLUSIONS

We showed that myofibroblasts and the accompanying collagen and elastin synthesis might be key factors in the development of endofibrosis. The special association with increased presence of PARs, factor X, and TF suggests that protease-mediated cell signaling could be a contributing component in the mechanisms leading to endofibrosis.

Lower limb vascular dysfunction in cyclists

Sports-related vascular insufficiency affecting the lower limbs is uncommon, and early signs and symptoms can be confused with musculoskeletal injuries. This is also the case among professional cyclists, who are always at the threshold between endurance and excess training. The aim of this review was to analyze the occurrence of vascular disorders in the lower limbs of cyclists and to discuss possible etiologies. Eighty-five texts, including papers and books, published from 1950 to 2012, were used. According to the literature reviewed, some cyclists receive a late diagnosis of vascular dysfunction due to a lack of familiarity of the medical team with this type of dysfunction. Data revealed that a reduced blood flow in the external iliac artery, especially on the left, is much more common than in the femoral and popliteal arteries, and that vascular impairment is responsible for the occurrence of early fatigue and reduced performance in cycling.

Histopathological comparison between endofibrosis of the high-performance cyclist and atherosclerosis in the external iliac artery

INTRODUCTION

High performance athletes, predominantly professional cyclists, can develop symptomatic arterial flow restriction in one or both legs during exercise. The ischemic symptoms are caused by endofibrosis and/or kinking of the external iliac artery. Because these athletes are young and have no classic risk factors for atherosclerosis, endofibrosis and atherosclerosis are considered different disease entities. We compared histology of endofibrotic lesions from young sportsmen with atherosclerotic lesions of the external iliac artery in elderly individuals.

METHODS AND RESULTS

Nineteen external iliac endarterectomy specimens from 18 cyclists (age 29 +/- 8 years) were compared with 42 external iliac segments from 22 elderly individuals (82 +/- 10 years). Ten arteries from elderly individuals revealed an intimal area that was >or=25% of the area encompassed by the internal elastic lamina and were considered atherosclerotic lesions. Stenosis was higher in patients (65% [interquartile range 50-75]) than in controls (11% [7-24]) (P < .0001). The endofibrotic lesions revealed loose connective tissue with moderate to high cellularity. Both in endofibrosis and atherosclerosis, most cells in the lesion were smooth muscle actin positive. In the endofibrosis specimens, loose fibers of collagen were observed, whereas in the atherosclerotic lesions collagen was mostly densely packed. Calcification of the lesion was not observed in endofibrotic lesions, whereas calcium deposition was observed in 80% of atherosclerotic lesions. Lymphocytes were present in 21% of endofibrotic lesions and in 80% of atherosclerotic cases. Macrophages were observed in 16% of endofibrotic lesions and in all atherosclerotic plaques. Luminal thrombosis was observed in one case of endofibrosis.

CONCLUSION

In the external iliac artery, atherosclerotic lesions and endofibrotic lesions of high performance cyclists have distinct morphologic characteristics. Endofibrosis in the external iliac artery may serve as soil for luminal thrombosis.

Intravenous conivaptan: effects on the QTc interval and other electrocardiographic parameters in healthy volunteers

Prolongation of the QT interval is clinically important because it may be associated with torsade de pointes, a potentially fatal arrhythmia. The objective of this study was to define the effects on electrocardiogram (ECG) of intravenous conivaptan, the first arginine vasopressin V1A/V2-receptor antagonist indicated for the treatment of euvolemic hyponatremia, on hospitalized patients without congestive heart failure. After a placebo run-in period, participants in this randomized, single-blind, placebo- and positive-controlled, parallel-group study received an intravenous 20-mg loading dose of conivaptan (day 1), followed by a 40-mg/d continuous infusion (days 1-4); a 20-mg loading dose of conivaptan (day 1), followed by an 80-mg/d continuous infusion (days 1-4); or moxifloxacin 400 mg (positive control) or placebo from day 1 to day 4. The primary ECG endpoint was QTc interval duration, which was determined by the individually corrected QT interval for each subset; secondary endpoints included QT intervals corrected with Bazett's formula and Fridericia's formula. No clinically notable changes in ECG parameters were associated with conivaptan, suggesting that conivaptan did not affect cardiac repolarization or cardiac conduction.

Hyponatremia, arginine vasopressin dysregulation, and vasopressin receptor antagonism

Hyponatremia is often associated with arginine vasopressin (AVP) dysregulation that is regulated by the hypothalamo-neurohypophyseal tract in response to changes in plasma osmolality, commonly in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Potentially lethal complications of hyponatremia most frequently involve the central nervous system and include anorexia, fatigue, lethargy, delirium, seizures, hypothermia and coma, and require prompt treatment. Chronic hyponatremia also complicates patient care and is associated with increased morbidity and mortality, particularly among patients with congestive heart failure. Conventional treatments for hyponatremia (e.g. fluid restriction, diuretic treatment, and sodium replacement) may not be effective in all patients and can lead to significant adverse events. Preclinical and clinical trial results have shown that AVP receptor antagonism is a promising approach to the treatment of hyponatremia that directly addresses the effects of increased AVP and consequent decreased aquaresis, the electrolyte-sparing excretion of free water. Agents that antagonize V(2) receptors promote aquaresis and can lead to increased serum sodium. Dual-receptor antagonism, in which both V(2) and V(1A) receptors are blocked, may provide additional benefits in patients with hyponatremia.

Comparison Between Duplex Scanning and Angiographic Findings in the Evaluation of Functional Iliac Obstruction in Top Endurance Athletes

OBJECTIVE

Review of a 10 year-experience, to evaluate the efficacy of pre-operative investigations in the detection of external iliac artery (EIA) endofibrosis in top endurance athletes.

DESIGN

Retrospective study.

MATERIALS

From September 1995 to March 2004, 13 highly-trained athletes (all men, mean age 32.3 years) underwent surgery for disease involving 14 lower limbs (11 left, one right, one bilateral).

METHODS

We compared ultrasound scan (US) and digital subtraction angiography (DSA) data, at rest and at hip flexion with intra-operative findings for all 14 lower limbs. We analyzed the presence of stenosis in the external and common iliac arteries, the presence of psoas muscle arteries and the presence of excessive EIA length.

RESULTS

In the affected limbs, before treatment, the mean ankle brachial index (ABI) at rest was 0.98 compared with 0.56 after exercise, p=0.0001. The sensitivities of the US vs DSA examination in the detection of external and common iliac artery stenosis were, respectively, 84.6 and 53.8% vs 53.8 and 12.5%. The muscle psoas artery was detected by DSA with a sensitivity of 57.1 and 100% specificity. For the detection of excessive EIA length, the sensitivity of US was 85.7% with 57.1% specificity.

CONCLUSIONS

A fall of ABI after exercise proves the presence of a significant stenosis in symptomatic athletes. Color coded duplex ultrasonography is recommended for non-invasive imaging of suspected endofibrotic stenosis in young athletes, since it detects reliably both stenosis and elongation of iliacal arteries.

Sports-Related Flow Limitations in the Iliac Arteries in Endurance Athletes

Approximately one in five top-level cyclists will develop sports-related flow limitations in the iliac arteries. These flow limitations may be caused by a vascular lumen narrowing due to endofibrotic thickening of the intima and/or by kinking of the vessels. In some athletes, extreme vessel length contributes to this kinking. Endofibrotic thickening is a result of a repetitive vessel damage due to haemodynamic and mechanical stress. Atherosclerotic intimal thickening is seldom encountered in these young athletes. This type of sports-related flow limitation shows no relationship with the classical risk factors for atherosclerosis like smoking, hypercholesterolaemia or family predisposition for arterial diseases. The patient's history is paramount for diagnosis. If an athlete reports typical claudication-like complaints in a leg at maximal effort, which disappear quickly at rest, approximately two out of three will have a flow limitation in the iliac artery. In current (sports) medical practice, this diagnosis is often missed, since a vascular cause is not expected in this healthy athletic population. Even if suspected, the routinely available diagnostic tests often appear insufficient. Definite diagnosis can be made by a combination of the patient's history and special designed tests consisting of a maximal cycle ergometer test with ankle blood pressure measurements and/or an echo-Doppler examination with provocative manoeuvres like hip flexion and exercise. Conservative treatment consists of diminishing or even completely stopping the provocative sports activity. If conservative treatment is insufficient or deemed unacceptable, surgical treatment might be considered. As surgery needs to be tailored to the underlying lesions, a detailed analysis before surgery is necessary. Standard clinical tests, used for visualising atherosclerotic diseases, are inadequate to identify and quantify the causes of flow limitations. Echo-Doppler examination and magnetic resonance angiography with both flexed and extended hips have been proven to be adequate tools. In particular, overprojection and eccentric location of the lesions seriously limit the usefulness of a two-dimensional technique like digital subtraction angiography. In the early stages, when kinking has not yet led to intimal thickening or excessive lengthening, simple surgical release of the iliac artery is effective. However, for patients with excessive vessel lengths or extensive endofibrotic thickening, a vascular reconstruction may be necessary. A major drawback of these interventions is that long-term effects and complications are unknown. As both the diagnostic methods and the treatments for this type of flow limitation differ substantially from routine vascular procedures, these patients should be examined in specialised research centres with appropriate diagnostic tools and medical experience.

External Iliac Endofibrosis in Endurance Athletes: A Novel Case in an Endurance Runner and a Review of the Literature

BACKGROUND

There is increasing recognition that high-performance athletes can develop symptomatic arterial flow restriction in one or both (15%) legs due to kinking and/or endofibrosis of their iliac arteries.

METHODS

Case report and review based on a Medline search of the literature.

RESULTS

A 51-year-old female, 24-hour endurance runner presented with a six-month history of rapidly progressing intermittent claudication affecting her right thigh and calf in the absence of classical risk factors for atherosclerosis. On the basis of invasive and non-invasive investigations, a provisional diagnosis of endofibrosis was made and she was treated successfully with angioplasty.

CONCLUSIONS

The epidemiology, optimal investigation and treatment of iliac endofibrosis in endurance athletes is poorly described. Each individual unit's experience is likely to be very small. A European register of such cases would increase our understanding of the condition and improve patient outcomes.

Epithelioid hemangioendothelioma of the common femoral vein: Case report and review of the literature

A young competitive skier had venous claudication. A stenosis of the left common femoral vein was revealed by means of an examination. Exploration and vein patch angioplasty were performed, and because of both the unusual appearance (focal thickening of vein wall) and the unclear etiology of the lesion, frozen and permanent sections of the wall were obtained. Epithelioid hemangioendothelioma, a rare intravascular sarcoma, was revealed by means of an examination of the permanent sections. Two additional procedures were required to completely excise the epithelioid hemangioendothelioma. We discuss these rare vascular malignancies and include a review of the available literature. Also, oncologic principles important in both the diagnosis and therapy of intravascular sarcomas are discussed.

Pressure measurements at rest and after heavy exercise to detect moderate arterial lesions in athletes

PURPOSE

This study defined how ankle arterial blood pressure measurements should be analyzed for the detection of moderate arterial disease (asymptomatic while walking). We used external iliac artery endofibrosis as a unique model of an isolated moderate arterial lesion, the role of which in exercise-related pain can be surgically proven.

METHODS

Patients who were ambulatory in our institutional referral center were studied. Brachial pressures, ankle pressures, and heart rate were measured simultaneously on all four limbs at rest and after maximal exercise in 108 healthy athletes and 78 patients (among 89 athletes referred for suspicion of endofibrosis) with confirmed or excluded external iliac endofibrosis. For these 78 patients, we calculated systolic ankle pressure change, ankle/brachial index, and deviation from the ankle/brachial index to heart rate regression line (DAHR) that was defined in the 108 healthy athletes.

RESULTS

In patients with endofibrosis, ankle/brachial index and ankle pressure were normal at rest. One minute after exercise, areas (mean +/- SE of area) under the receiver operating characteristics curve for the diagnosis of endofibrosis were 0.91 +/- 0.02, 0.91 +/- 0.03, 0.95 +/- 0.02, and 0.96 +/- 0.02 for ankle pressure, pressure change, ankle/brachial index, and DAHR, respectively. For all criteria, area decreased with time in the recovery period.

CONCLUSION

After heavy-load exercise, the ankle/brachial index at minute 1 should be used rather than the systolic ankle pressure value or ankle pressure change as a means of improving the efficacy of the detection of endofibrosis in athletes. A 0.66 value of the index at minute 1 after maximal exercise seems an optimal cutoff point for clinical use, providing a 90% sensitivity rate and 87% specificity rate in the diagnosis of moderate arterial lesions. At rest and after 1 minute of recovery, the ankle/brachial index to heart rate relationship should be considered to be an efficient tool for analyzing the results of pressures measurements and improving detection efficiency.