Filarial extract of Litomosoides sigmodontis induces a type 2 immune response and attenuates plaque development in hyperlipidemic ApoE-knockout mice.

A type 1 immune response is involved in atherosclerosis progression, whereas the role of a type 2 polarization, especially with regard to an enhanced T helper (Th)2 cell differentiation, is still unclear. Helminths trigger type 2 immune responses, protecting the host from inflammatory disorders. We investigated whether an increased type 2 polarization by administration of Litomosoides sigmodontis adult worm extract (LsAg) affects atherosclerosis in apolipoprotein E-deficient (ApoE-/-) mice. Injections of 50 µg LsAg, i.p. into ApoE-/- mice induced a type 2 immune response shown by increased frequencies of peritoneal eosinophils and alternatively activated macrophages. To analyze the effect of LsAg on atherosclerosis initiation, ApoE-/- mice received a high-fat diet for 12 wk and weekly injections of 50 µg LsAg from wk 5 to 12. Therapeutic effects on advanced atherosclerosis were analyzed in mice that were fed a high-fat diet for 12 wk followed by 12 wk of normal chow and weekly LsAg injections. Both preventive and therapeutic LsAg application significantly decreased plaque size. Therapeutic treatment even caused regression of plaque size and macrophage density in the aortic root and reduced Th1-specific gene expression and intraplaque inflammation. In addition, plaque size after therapeutic treatment was inversely correlated with plaque-infiltrated alternatively activated macrophages. In vitro, LsAg treatment of HUVECs reduced intracellular levels of phosphorylated NF-κB-p65, IκB-α, and JNK1/2. In bifurcation flow-through slides, THP-1 cell adhesion to a HUVEC monolayer was decreased by LsAg in regions of nonuniform shear stress. Applying inhibitors of the respective kinases suggests JNK1/2 inhibition is involved in the suppressed cell adhesion. A switch to an enhanced type 2 immune response by LsAg exerts antiatherogenic effects on murine plaque development, indicating a protective role of a hampered type 1 polarization. In vitro, LsAg affects endothelial signaling pathways, among which JNK1/2 inhibition seems to be involved in the suppression of monocytic cell adhesion under proatherogenic shear stress.-Constanze, K., Tauchi, M., Furtmair, R., Urschel, K., Raaz-Schrauder, D., Neumann, A.-L., Frohberger, S. J., Hoerauf, A., Regus, S., Lang, W., Sagban, T. A., Stumpfe, F. M., Achenbach, S., Hübner, M. P., Dietel, B. Filarial extract of Litomosoides sigmodontis induces a type 2 immune response and attenuates plaque development in hyperlipidemic ApoE-knockout mice.

Wound closure by means of free flap and arteriovenous loop: Development of flap autonomy in the long-term follow-up.

Free flaps in combination with arterial reconstruction by means of arteriovenous loops or bypass have, meanwhile, been established as a therapeutic option in defect reconstruction for areas without recipient vessels. Our aim was to analyse the long-term performance, flap autonomy, and the flap perfusion. Patients receiving this combined reconstruction at a single-centre institution were included. During follow-up examination, the patency of arterial reconstruction was investigated by duplex ultrasound. Flap micro-circulation was assessed by laser Doppler flowmetry and white light tissue spectrometry (O2C) as well as by indocyanine green fluorescence angiography. Twenty-three patients could be clinically followed up. Duplex ultrasound showed, in four cases, arterial pedicle occlusion in spite of vital flap. Comparison of the O2C perfusion parameters between flaps with occluded pedicles and those with intact inflow showed no significant difference (parameters sO2: P = .82; Flow: P = .31). Similar results were obtained by fluorescence angiography; no significant difference could be detected between both groups (parameters Ingress P = .13; Ingressrate P = .54). Combined vascular reconstruction with free tissue transfer is associated with a good long-term outcome and wound closure. Even after flap transplantation to areas with critical tissue perfusion, the flap can develop autonomy and thus survive after pedicle occlusion.

Quantitative assessment of microperfusion by indocyanine green angiography in kidney transplantation resembles chronic morphological changes in kidney specimens.

OBJECTIVE: ICG fluorescence angiography enables a quantitative real-time perfusion assessment in kidney transplantation. The results of intraoperative microperfusion of the kidney allograft were compared to the renal chronicity score in pre-transplantation kidney biopsy specimens. The intrarenal resistance index was calculated by duplex sonography as a method of reference. METHODS: Seventy-seven patients with end-stage renal disease undergoing kidney transplantation were prospectively included in two centers. Correlation analysis of chronic changes in kidney biopsy specimens and the IN of ICG fluorescence signal were investigated. RESULTS: The results yielded a significantly negative correlation for the renal chronicity (r = -0.294, P = 0.017) as well as the intestinal fibrosis and tubular atrophy score (r = -0.328, P = 0.007). There was a significant inverse relationship between the IN and the mean RI values of the upper pole of the kidney allograft. CONCLUSIONS: In summary, fluorescence angiography reflects preexisting morphological changes of the renal cortex. ICG angiography may serve as an alternative method for the assessment of microperfusion of the kidney allograft.

Pilot Assessment of the Angiosome Concept by Intra-operative Fluorescence Angiography After Tibial Bypass Surgery.

OBJECTIVES: The "angiosome" concept as a model for decision making in revascularisation of patients with critical limb ischaemia (CLI) has been subject to lively discussion in recent years. The aim of this prospective pilot study was to use intra-operative fluorescence angiography to provide further data on the angiosome concept on the level of microcirculation after tibial bypass surgery. DESIGN, MATERIALS, AND METHODS: This was a prospective analysis of 40 patients presenting with CLI Rutherford stage IV to VI before and after tibial bypass surgery. The macrocirculation was measured by the ankle brachial index. Skin microcirculation was assessed by intra-operative fluorescence angiography. The alteration of microcirculation was compared in direct and indirect revascularised angiosomes. Clinical follow-up investigations were performed and the wound healing rate was compared between the different revascularisation methods. RESULTS: Cumulated microcirculation parameters showed a significant improvement after surgery (ingress, ingress rate p<.001). Likewise, general microcirculatory improvement was observed in each foot angiosome after revascularisation, regardless of the tibial artery revascularised. Furthermore, a comparison of the direct (DR) and the indirect revascularised (IR) angiosomes did not show a significant difference concerning the improvement of microcirculation (difference DR-IR, ingress: 1.69, 95% CI 71.73-75.11; ingress rate: 0.08, 95% CI -12.91 to 13.07). The wound healing rate was similar in both groups, although the time to wound healing was faster by on average 2.5 months in the DR group (p=.083). CONCLUSION: Microcirculatory improvement was seen over the whole foot after tibial bypass. Therefore, fluorescence angiography is a promising tool to evaluate the angiosome concept in future larger studies. Clinicaltrials.gov: NCT03012750.

Dosing of indocyanine green for intraoperative laser fluorescence angiography in kidney transplantation.

OBJECTIVE: Sufficient blood supply is a crucial factor determining postoperative allograft function in kidney transplantation. Therefore, besides the surgeon's individual impression, a method for evaluating the quality of the organ's microperfusion is required. Laser fluorescence angiography with indocyanine green (ICG) is an emerging tool for this purpose. However, no reproducible quantification of ICG fluorescence has been performed in transplantation so far. METHODS: This retrospective two-center study was designed to evaluate the dosing of ICG for intraoperative laser fluorescence angiography in kidney transplantation. The Spy Elite® system (NOVADAQ, Canada) was employed for quantitative assessment of allograft microperfusion. ICG was administered systemically 5 minutes after reperfusion applying doses between 0.25 and 0.01 mg ICG per kg body weight. Quantitative assessment was performed with the implemented SPY-Q Software. RESULTS: A total of 57 kidney recipients were included in two centers. The generated curves showing ICG IN and EgR were not evaluable due to oversensing when doses exceeded 0.02 mg per kg body weight. CONCLUSIONS: Fluorescence angiography with ICG is an emerging tool for the intraoperative quality control and evaluation of microperfusion in kidney transplantation. A dose of 0.02 mg ICG per kg body weight is recommended to ensure the quantitative assessment with SPY-Q.

Immediate changes of angiosome perfusion during tibial angioplasty.

OBJECTIVE: In recent years, a controversial discussion about the clinical relevance of the angiosome concept during tibial angioplasty has developed. Therefore, we conducted a prospective study to evaluate the angiosome concept on the level of microcirculation during tibial vascular interventions. METHODS: Thirty patients with isolated tibial angioplasty were examined prospectively. Macrocirculation was evaluated by measurement of the ankle-brachial index (ABI). For the assessment of microcirculation, a combined method of laser Doppler flowmetry and tissue spectrometry (O2C; LEA Medizintechnik GmbH, Giessen, Germany) was applied. Microcirculatory parameters were measured continuously during the procedures. Measuring points were located over different angiosomes of the index foot; a control probe was placed on the contralateral leg. RESULTS: Cumulated microcirculation parameters (sO2, flow) as well as the ABI showed a significant improvement postinterventionally (ABI, P < .001; sO2, P < .001; flow, P < .001). Assessment of the separate angiosomes of the index leg and the comparison of the directly revascularized (DR) and indirectly revascularized (IR) angiosomes showed no significant difference concerning the microperfusion postinterventionally (DR - IR: sO2, P = .399; flow, P = .909) as well as during angioplasty. Even a further subdivision of the collective into patients with diabetes (sO2, P = .445; flow, P =.758) and renal insufficiency (sO2, P = .246; flow, P = .691) could not demonstrate a superiority of the direct revascularization at the level of microcirculation in these patients (comparison DR - IR). CONCLUSIONS: There is a significant overall improvement in tissue perfusion of the foot immediately after tibial angioplasty. The effect shown in this study, however, was found to be global and was not restricted to certain borders, such as defined by angiosomes.

Microcirculation Evaluated by Intraoperative Fluorescence Angiography after Tibial Bypass Surgery.

BACKGROUND: Intact microperfusion of the foot in the critical ischemic limb remains a crucial condition for ulcer healing. Aim of this clinical study was to evaluate the immediate effect of tibial bypass surgery on the microcirculation by usage of fluorescence angiography. METHODS: Prospective analysis of 33 patients presenting with critical limb ischemia (Rutherford IV-VI) undergoing tibial bypass surgery was performed. Macroperfusion was investigated by measurement of ankle-brachial index. For assessment of microperfusion, intraoperative fluorescence angiography (SPY Elite, NOVADAQ) was undertaken during general anesthesia immediately before and after operation. For each investigation, a fluorescence dye (Indocyanine green) with an amount of 0.1 mg/kg was administered intravenously. Follow-up investigations were performed to assess the clinical outcome. RESULTS: The mean follow-up time was 8.28 (±4.46) months. The parameters Ingress (IN) and Ingress rate (InR) of the fluorescence dye representing the microcirculation showed a significant improvement to preoperative values and correlated with the ankle-brachial index significantly. Furthermore, a significant difference between the individual improvement of the microcirculation parameters (preoperative-postoperative) between patients with postoperative clinical improvement (wound healing, absence of rest pain) and those without could be demonstrated (InR: P = 0.039, IN: P = 0.036). CONCLUSIONS: The parameters IN and InR significantly reproduced the postoperative improvement of the microcirculation. An increased ankle-brachial index significantly correlated with increased microcirculation parameters. A better clinical outcome was found in those patients who had a higher relative improvement of microcirculation postoperatively.

Timing of first arteriovenous fistula cannulation in children on hemodialysis.

BACKGROUND: Due to lower complication rates in comparison to central venous catheter (CVC) arteriovenous fistulas (AVFs) are now the preferred hemodialysis access. Recommendations for the first access cannulation range from 6 to 12 weeks, which could lead to temporary or even permanent preference for CVC while awaiting the maturation of the newly created AVF. The aim of this study was to evaluate the influence of first cannulation of AVFs on primary (PP) and secondary (SP) patency rates in children on hemodialysis (HD). METHODS: This was a retrospective cohort study of 42 pediatric patients with a median age of 14 (range 7-17) years. At the time of surgical AVF creation 21 patients (end-stage renal disease) were still on HD via CVC or peritoneal catheter, while 21 were pre-emptive with initiation of HD expected within a few weeks. All patients received an AVF by the same experienced surgeon between February 1993 and May 2014. Primary failure (PF) was defined as the inability to use the AVF even once due to absent maturation or occlusion within 4 weeks after creation. PP was defined as the interval from time of access placement to any intervention designed to maintain or reestablish patency, to access thrombosis or the time of measurement of patency, while SP was defined as the total lifespan from creation to access abandonment, end of follow-up or loss. RESULTS: Primary failure was observed in six (14.3 %) of 42 AVFs (all radiocephalic fistulas) within the first 10 days after cannulation. Excluding PF, the PP/SP rates at 1, 3, 6, 12, 18 and 24 months were 100/100, 91/99, 86/98, 76/95, 55/85 and 44/77 %, respectively. There was a significant decrease in PP when first cannulation was performed within the first 30 days after creation compared to first cannulation performed after 30 days (p = 0.004). In terms of PP/SP outcome and timing of the first cannulation, there was no significant difference in thee outcome of PP/SP between first cannulation within the first 45 days after creation and that after 45 days (p = 0.091/0.883). CONCLUSIONS: The findings suggest that cannulation of AVF within 30 days after surgical creation reduces PP, while SP may be influenced less by time until cannulation. We also found no significant differences in PP after maturing periods of >45 days.

Outcomes and Influence of the Pedal Arch in Below-the-Knee Angioplasty in Patients with End-Stage Renal Disease and Critical Limb Ischemia.

BACKGROUND: Management of dialysis patients with critical limb ischemia (CLI) still represents a challenge to vascular medicine, whereas the effects of the pedal arch quality in these patients with predominant affection of the infrapopliteal vessels have rarely been evaluated. Therefore, our aim was to analyze the outcomes of infrapopliteal angioplasty in the setting of chronic renal failure (end-stage renal disease) and evaluate the influence of the pedal arch involvement on clinical success. METHODS: Prospective follow-up of 32 ERSD patients on hemodialysis (mean age, 72 years) with CLI and consecutive infrapopliteal angioplasty over a 5-year period 2010-2014 was performed. Mean follow-up was 10 months (range, 0-51 months). Statistical end points were defined for amputation-free survival, overall survival, and wound healing. Each patient's pedal arch was classified in 4 categories according to patency on completion angiography and the influence of the pedal arch quality on end points was assessed. RESULTS: A total of 44 vessels in 32 ischemic legs were treated. Technical success was achieved in 96% of patients, no major complications were observed. A 30-day mortality rate amounted 6% with no procedure-related deaths. The 1-year amputation-free survival rate was 56% and 34% at 2 years. Two major amputations were required. Subsequent revascularization procedures were necessary in 11 patients (10 redo angioplasty, 1 pedal bypass graft). The pedal arch was classified as category I in 1 patient (3%), category IIa in 12 (38%), IIb in 3 (9%), and III in 16 patients (50%). No statistical significant differences in terms of survival or wound-healing rate were observed between those groups, and the pedal arch quality had no impact on predefined end points. CONCLUSIONS: End-stage renal disease patients represent a subgroup with poor prognosis of limb salvage in CLI. Amputation-free survival remains poor and based on these data, an endovascular therapy is feasible and safe in these highly multimorbid patients. The quality of the pedal arch was not found to have any impact on wound healing or survival in the present study.

Results of Renal Transplantation on Alloplastic Arterial Grafts.

BACKGROUND: The aim of this retrospective study was to report results of a consecutive series of kidney transplant patients in whom the renal artery was implanted on a prosthetic vascular graft (PVG). METHODS: Between January 2011 and December 2014, 208 deceased donor renal transplantations (68 female, 140 male, mean age 52, SD 16 years) were performed. Medical charts and outpatient clinical records of patients who had undergone renal artery implantation on a PVG were reviewed. Extensive literature research added to our 4 patients further 170 published cases during 1989 and 2015 and was compared with regular transplanted patients. Data on patient characteristics, prior vascular procedures, postoperative and long-term outcome were collected. RESULTS: Patients with transplant renal artery anastomosis on a PVG were 4 years older than the control group. Function of the graft was similar in these patients compared to regular renal transplant patients. Resistance indices assessed in our clinic over the entire follow-up period showed also no significant difference between the 2 groups. Thirty-day mortality was 6% (none in our group), which occurred mostly in combination when renal transplantation and PVG replacement was performed simultaneously. CONCLUSION: Grafting of the renal artery to a PVG is feasible and yields good results, despite the technical difficulties involved.

Isolated testicular pain mimicking ruptured abdominal aortic aneurysm in a nonagenarian.

Ruptured abdominal aortic aneurysm commonly presents as acute abdominal or lower back pain and hemodynamic instability. We discuss the case of a 90-year-old patient who presented to the emergency unit with a 3-day history of left testicular pain. Ultrasound scan demonstrated and a computed tomography scan confirmed a 6 cm in diameter ruptured abdominal aortic aneurysm with enlargement and hematoma of the left psoas muscle causing the symptoms. This atypical presentation highlights the need for clinical vigilance and emergency physician­performed ultrasound scan in the older patients with seemingly benign testicular symptoms.

[Iliac endofibrosis in high-performance sports: an interdisciplinary diagnostic challenge]. / Die iliakale Endofibrose im Hochleistungssport - eine diagnostische interdisziplinäre Herausforderung.

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.

Pilot study using intraoperative fluorescence angiography during arteriovenous hemodialysis access surgery.

INTRODUCTION:: In this pilot study, we used indocyanine green fluorescence angiography during hemodialysis access surgery. The aim was to evaluate its relevance as a diagnostic tool to visualize changes in hand microperfusion. PATIENTS AND METHODS:: In this prospective single-center study, 47 adult patients (33 male, 14 female) with renal disease (24 preemptive, 23 endstage) were enrolled. Surgical creation of an arteriovenous fistula was performed (22 forearm, 25 upper arm). Microperfusion of the ipsilateral hand and fingers was evaluated intraoperatively using indocyanine green fluorescence angiography. We compared the cumulated microperfusion parameters ingress (In) and ingress rate (InR) before and after opening of the anastomosis. To compare the dimension of microcirculatory decline, we calculated the ratios of the parameters (RatioIn and RatioInR) after to those before anastomosis opening. RESULTS:: The cumulated microperfusion parameters In and InR showed a significant decrease after completion of anastomosis and declamping. This effect has been seen in all patients for the hand and for each finger consecutively. During follow-up (mean 4.6, range 3-11 months), 5 patients (10.6%) complained about hemodialysis access-induced distal ischemia. The ratio of intraoperative microperfusion in those five hemodialysis access-induced ischemia patients was significantly lower compared to asymptomatic patients (RatioIn 0.23 vs 0.58, p = 0.001, and RatioInR 0.25 vs 0.62, p = 0.003). CONCLUSION:: Intraoperative fluorescence angiography could visualize the deterioration of ipsilateral hand microperfusion after surgical creation of an arteriovenous fistula. It seems to be a promising tool to detect patients at risk for hemodialysis access-induced distal ischemia early in the peri- or even intraoperative stage.

Open Versus Endovascular Revascularization of Below-Knee Arteries in Patients With End-Stage Renal Disease and Critical Limb Ischemia.

BACKGROUND:: Evaluation of below-the-knee open revascularization (OR) versus endovascular revascularization (EVT) in patients with end-stage renal disease and critical limb ischemia (CLI) was performed. PATIENTS AND METHODS:: Seventy-seven dialysis patients with CLI and infrapopliteal involvement from 2007 to 2017 were included. Thirty-five patients received OR and 42 patients were treated with EVT. Survival, amputation-free survival (AFS) and wound-healing were evaluated. Furthermore, both groups were analyzed for differences as to anatomic (lesion length, runoff, pedal arch classification) and clinical (VSG risk score, WIfI score) characteristics. RESULTS:: Amputation-free survival (1-year AFS: OR 54.5% vs 47.6% in EVT, 2-year AFS OR 38.3% vs 23.9% EVT, P = .201) did not significantly differ between OR and EVT nor did the wound healing rate (29% OR vs 31% EVT, P = .532). Overall survival was noticeably poor (1-year survival: 66.7% in OR and 49% in EVT, 2-year survival OR 47.4% vs EVT 27.7%; P = .088); evaluation of peripheral runoff (Rutherford score 6.9 OR vs 7.1 EVT, P = .499) and pedal arch classification as well as WIfI or VSG risk score (9.8 OR vs 9.6 EVT, P = .673) could not detect significant differences as to both the groups. Treated median lesion length was significantly increased in OR patients (OR 26 cm vs EVT 7 cm, P < .001), whereas the incidence of major adverse cardiac events was higher in EVT patients (67% in EVT vs 40% OR, P = .023). CONCLUSION:: OR and EVT showed comparable outcomes as to AFS and wound healing. Poor overall survival remains the determining factor in patients with ESRD having CLI. Both groups differ in terms of anatomic features as lesion length and severity of comorbidities; considering the comparable long-term outcomes, decision-making should be based on these premises; individually applied, each method can contribute to limb salvage, although the overall survival remains limited.

Time-extended local rtPA infiltration for acutely thrombosed hemodialysis fistulas.

INTRODUCTION: This study describes results of a modified local thrombolysis technique for acutely thrombosed hemodialysis (HD) arteriovenous fistulas (AVF), which is characterized by prolonged recombinant tissue plasminogen activator (rtPA) local exposure times. Contrary to the standard lyse- and- wait (L&W) technique with local reaction times of 20-40 minutes, the modified protocol allows timing of challenging angioplasty maneuvers to the next regular working day. METHODS: From February 2009 to April 2014, 84 patients on HD presented with 152 acutely thrombosed AVF. They proceeded to local thrombolysis including a single shot infiltration of rtPA, local reaction time up to 40 hours and finally percutaneous stenosis angioplasty. Success rates, major adverse events and need for temporary catheter placements (TCP) were retrospectively analyzed. FINDINGS: The local thrombolysis time after single shot infiltration was 18.6 ± 6.2 (range 2-40) hours. Mean rtPA- dosage was 2.7 mg ± 1.2. The overall success rate was 89.5% and the major complication rate was 3.3%, whereas TCP was necessary in 12.5%. The PP/SP at 1, 3, 6, 12, 18, and 24 month were 86% ± 3%/95% ± 2%, 68% ± 4%/92% ± 2%, 43% ± 4%/90% ± 2%, 28% ± 4%/82% ± 3%, 12% ± 3%/82% ± 3%, 7% ± 2%/63% ± 4%, respectively. CONCLUSION: The modified L&W technique with prolonged local rtPA reaction times is a safe and effective declotting procedure. The need for TCP was not increased and therefore comparable to the standard technique.

MRI to investigate iliac artery wall thickness in triathletes.

OBJECTIVES: Endofibrosis was first described in endurance athletes. This rare disease is characterized by intimal hyperplasia of iliac arteries. Due to non-specific symptoms diagnosing could be very challenging and delayed. This represents a serious problem not only for affected athletes but also for consulting physicians. The aim of this study was to analyze intimal thickness of iliac arteries using non-contrast magnetic resonance imaging (MRI) in competitive triathletes suffering from exercise induced leg pain consistent with symptoms caused by endofibrosis. METHODS: 18 highly trained triathletes (16 triathletes, 12 male) with a mean age of 45.4 ± 10.2 years were investigated by non-contrast MRI. We divided subjects into two groups: 10 complaint about exercise- induced leg pain and 7 were free of any symptoms. In all 10 symptomatic athletes consulting physicians excluded musculoskeletal or neurological disorders before and we suspected endofibrosis. One patient was excluded from statistical analysis due to a known recurrent external iliac artery (EIA) occlusion after surgical repair 6 month ago. RESULTS: Mean wall thickness (T) of all 17 subjects was 1.34 ± 0.11mm for the common iliac artery (CIA) and 1.74 ± 0.18mm for the EIA. We found no significant differences by comparing T of symptomatic (s) and asymptomatic (a) legs. There were no significant differences in mean ratio of patent artery to whole artery between the symptomatic and asymptomatic legs for the CIA (0.81 vs 0.82, p = 0.87) and for the EIA (0.71 vs 0.72, p = 0.78). MRI shows a thickening of the left EIA (4.41mm) in the patient who suffered from recurrent occlusion of the left EIA and after surgical repair and histological examination confirmed an endofibrotic lesion. CONCLUSION: Non-contrast MRI seems to be an appropriate diagnostic tool to exclude endofibrosis in triathletes, but it cannot be recommended as initial screening modality for athletes suffering from exercise-induced leg pain.