Iliac artery endofibrosis is a real, probably underdiagnosed cause of exertional leg symptoms in endurance cyclists, most reliably confirmed with post-maximal-exercise ankle-brachial-index testing
Interpretation
Schep et al.'s prospective study of 80 endurance athletes found flow limitation in 63% of examined legs, mostly from arterial kinking, with 87% of surgically treated athletes returning to their desired competitive level. Hinchliffe et al.'s Delphi consensus confirms exercise testing and duplex ultrasound as the agreed diagnostic approach and vein-patch endarterectomy as the preferred surgical treatment. Martinez and Wells' patient-information summary puts prevalence at 10-20% in elite endurance athletes, with affected cyclists typically having ridden a mean of ~120,000km before symptoms appear and a diagnosis delay of 12-41 months — the condition is plausibly common and routinely missed, not rare.
Practical implication
Flag unexplained, exertion-only leg weakness, numbness or pain in high-volume cyclists as a real differential diagnosis worth a post-maximal-exercise ABI test, rather than assuming it's purely muscular or positional. The evidence base is built on small specialist-centre case series and consensus, not large trials — appropriate for raising awareness, not for precise prevalence claims.
Sources
3 sources, independently verified.
Flow limitation was found in 63% of legs examined (58/92), most often caused by arterial kinking (69% of affected legs). Of the legs that went to surgery (40%), all reported improvement, and 87% of those athletes returned to their desired competitive level. The foundational prospective study establishing iliac artery endofibrosis as a real, surgically addressable cause of exertional leg symptoms in endurance athletes, not simply overuse pain.
A 3-round Delphi consensus among specialists (70% agreement threshold) agreed that exercise testing is a valid diagnostic step, duplex ultrasound is useful, endarterectomy with vein patch is the preferred surgical approach over endovascular treatment, and continuing to exercise through symptoms likely allows the condition to progress while stopping may prevent it. Disagreement remained on exact non-invasive diagnostic criteria and post-operative return-to-exercise timing.
Patient-information summary noting the condition affects the external iliac in over 90% of cases, is more common on the left side, and is linked to repeated hip-flexion stress — affected cyclists had typically ridden a mean of ~120,000km before symptoms appeared, at over 14,500km/year. Estimated prevalence of 10-20% in elite endurance athletes, more common in men and usually under 40, with a typical diagnosis delay of 12-41 months.