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 recognized in Europe where cycling is more popular, it is becoming increasingly recognized in Australia, New Zealand, USA and England.
The diagnosis is frequently missed, as clinicians rarely consider a vascular condition in a young, otherwise healthy individual. To make matters more difficult, it is rare to find an abnormality on examination alone, 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 pelvic artery (usually the external iliac artery) impedes blood flow during maximal lower limb exertion. This causes unusual turbulence in the artery resulting in thickening of the wall referred to as Endofibrosis.
The pathological changes are usually subtle in the early stages. With time the wall of the artery becomes increasingly thickened, due to endofibrosis, and if left untreated, atheroma can supervene at the site of injury resulting in thrombosis.
How do patients present?
It manifests itself by causing “claudication” (a cramping sensation in the muscles) during maximal exertion. It is variously described as a cramp, a heaviness or fatigue, which causes a reduction in power and an inability to sustain maximal exertion. For elite athletes this results in sub-optimal performances, and clearly impacts on 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 exercise, 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/back problems, as they are often desperate for a diagnosis, and more importantly an effective treatment.
There are usually no positive physical findings on examination. All peripheral pulses are present and equal in both lower limbs, and only rarely can a bruit be heard over the femoral artery.
What special investigations are required?
Conventional imaging, i.e. duplex ultrasound, and CT scan is more often than not, within the normal range. Subtle changes with wall thickening due to endofibrosis 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 a flow limiting stenosis due to endofibrosis, especially when similar changes are not observed on the other 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 for 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 the symptoms much worse, and should therefore be avoided.
Vein Patch Angioplasty of the external iliac artery offers the best chance for cure. It is performed as an open procedure, and has a very high rate of success. Read more about the procedure here.
What is the likely outcome?
The response to vein patch angioplasty is excellent with complete relief of symptoms in virtually all cases.
Long term data is not yet available, but will be in due course. Whether this condition predisposes to other forms of vascular disease remains to be seen.