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

Abstract

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. 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. 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%). 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.