Iliac Artery Endofibrosis
Could exercise injure our vascular system? We are all aware of the multitude of benefits from regular exercise. There is robust evidence that exercise improves the strength of our musculoskeletal system, decreases our blood pressure, improves our lipid profiles, and decreases our chance of diabetes and certain cancers and so on. Largely, we know that our vascular function is also markedly improved with exercise. However, when taking care of endurance athletes, especially cyclists, there is a caveat.
Iliac artery endofibrosis is a rare condition caused by thickening of the vessel intima that differs from arteriosclerotic vascular disease. The endurance athlete may develop thickening of the subendothelial layer of the artery from repetitive micro trauma; this trauma is thought to be caused by high blood flow, elevated blood pressure with exercise and repetitive stretching of the vessel near the hip joint. The accumulation of injury may result in a progressive stenosis of the artery, often just above the inguinal ligament.
This entity has been identified in athletes since the 1980’s with increasing awareness more recently. The elite cyclist is clearly the most likely to present with this problem, however, this diagnosis should be considered in all endurance athletes with vague leg pain.
Generally, this is a challenging diagnosis to make, especially considering that vascular syndromes would be unexpected in these athletes, and this leads to frequent delays in diagnosis. The athlete may present with vague leg pain associated with intense exercise which quickly disappears with cessation. They might complain of leg cramps, loss of power and a “dead” leg. The k ey initial evaluation includes listening for bruits and vascular testing both pre and post exercise, trying to unmask the symptoms.
Management involves discussing the natural history with the athlete, modification of exercise in many athletes, and endarterectomy and vein patch in a very select group of athletes. Unfortunately, there is very little longterm evidence for this problem. This lack of information led to the development of INSITE, which is a multidisciplinary group with a common interest in this clinical problem. The INSITE (International Study Group for Identification and Treatment of Endofibrosis) Collaborators has been formed to find consensus and provide a starting point for future study and guidelines.
While there is no doubt of the benefits of exercise and movement, for those who take care of endurance athletes, especially cyclists, this rare disorder is important and interesting.
INSITE Collaborators, Diagnosis and Management of Iliac Artery Endofibrosis: Results of Delphi Consensus Study, European Journal of Endovascular Surgery, 2016.