Moonee Ponds - Malvern - Clayton - Gisborne
What is Claudication in Elite Athletes?
Claudication in Elite Athletes is a recently identified entity occurring mainly in elite cyclists and tri-athletes. It was first described as recently as the mid 1980s and although it is better recognised in Europe where cycling is more prolific it is now becoming more recognised in Australia, New Zealand, USA and England.
The diagnosis is frequently missed as clinicians rarely consider vascular disease in a young, otherwise health individual. To make matters more difficult, physical findings to support the diagnosis are rarely evident, especially in the early phase.
How does it occur?
The mechanism of injury to the artery remains somewhat conjectural. The most popular theory is that the artery (usually the external iliac artery) elongates during maximal lower limb exertion. It is able to do so, as the artery is elastic, and therefore dilates and elongates to accommodate the increased flow required with exercise. As the artery is fixed at its origin and termination as it leaves the pelvis, it can kink at any point between the fixation points. It is indeed at the site of kinking that changes occur in the wall of the artery leading to Endofibrosis.
The pathological changes are usually subtle in the early stages. With time the wall of the artery becomes thickened due to endofibrosis and if left untreated, atheroma can occur ultimately at the site of injury resulting in thrombosis.
How do patients present?
It manifests itself by causing “claudication” in the athlete during maximal exertion. It is variously described as a cramping of the muscle, a heaviness or weakness, a build up of lactate or similar descriptions, all of which are consistent for causing a reduction in power and an inability to sustain maximal exertion. For elite athletes this results in sub-optimal performances, and clearly impacts upon competitive outcomes.
How is the diagnosis made?
In order to make the diagnosis, the clinician must have an index of suspicion. A good history is vital. The symptoms tend to involve the larger muscle groups such as the quadriceps and hamstrings. It occurs after a period of sustained excercise, not immediately, thus causing an inability to sustain maximal effort. Many athletes become frustrated as they undergo numerous investigations looking for alternative causes such as musculoskeletal problems/back problems, and they are often desperate for a diagnosis, and more importantly effective treatment.
There are usually no positive physical findings on examination. All peripheral pulses are present and equal in both lower limbs, and rarely have I can a bruit over the femoral artery.
What special investigations are required?
Conventional imaging, ie duplex ultrasound and CT scan is more that often not, within normal range. Subtle changes with wall thickening due to the fibrosis may be missed unless there is an index of suspicion.
The diagnosis is best made by performing a post-exercise Duplex examination of the external iliac artery. This is best achieved using a wind-trainer and scanning the patient immediately following the onset of symptoms.
At that point, a duplex examination of the external iliac artery is undertaken. An increase in systolic velocity to 500cm/sec or more is diagnostic of flow liminting stenosis due to endofibrosis, especially when similar changes are not observed on the contralateral, asymptomatic side.
In addition, a post-exercise ankle-brachial index (ABI) will show a marked fall on the affected side.
CT angiography and digital subtraction angiography are not required, but if performed, will often reveal minor irregularities in the vessel wall, consistent with endofibrosis. Moreover, obvious kinking of an elongated artery can sometimes be demonstrated by obtaining views of the artery with the hip in a flexed position.
What treatment is available?
One alternative is to recommend a change in activity, a very sensible recommendation to recreational athletes. Many take this advice on board, though others will demand a procedure to relieve their symptoms. A clear and frank discussion regarding the risks of intervention should ensue.
For elite athletes who wish to pursue their dream, the symptoms will only disappear with appropriate intervention.
Endovascular treatment has NO role in this condition. Indeed stenting of the external iliac artery, may well make symptoms much worse, and should therefore be discouraged. Vein Patch Angioplasty of the affected artery offers the best chance for cure. It is performed as an open procedure, and has a very high rate of success.