Exercise Induced Arterial Endofibrosis
Every so often in the cycling press we’ll read about a pro who has developed arterial problems in his or her leg. The headlines will often referred to it as “Iliac Artery surgery”. The medical term for the problem is “Exercise Induced Arterial Endofibrosis”. What exactly is going on here ?
It’s an injury the cycling world sees quite often. To name a few, Travis Meyer’s season came to an abrupt end to recover from Iliac Artery surgery. Stuart O’Grady went through through it a few years back, and just recently Theo Boss went under the knife.
Iliac Artery Endofibrosis
by Dr. Dominic Briscomb
Simply put, when an athlete (it doesn’t just happen to cyclists) bends forward and exercises, it can put pressure and/or a kink the artery supplying the working muscles with oxygen and sugars and so forth. The artery effected in cyclists is the external iliac which is found deep and low in the abdomen, just above where it heads into the leg (there is two of them, left and right) . It supplies the majority of the blood to the leg. It can also occur in other arteries in the leg e.g. knee, but not usually in cyclists.
The theory is that the longer time spent bending forward and exercising, the more the artery can be kinked and irritated. Over time, the body responds to this irritation by making the artery harder thereby reducing the irritation to the artery (a good outcome), but this hardening also reduces the blood supply to the leg when exercising (a bad outcome for bike racers).
Typically the patient complains of weakness and cramping, ‘bursting’ or aching pain of a single leg only during heavy efforts on the bike. They can’t ride through it, and in fact, the more they persist, the worse it gets. The onset is usually slow, over months, but extremely consistent; with increasing intensity comes decreasing strength. The cyclist may be full of self doubt at this stage, because they can’t work out why the more they train, the harder they try, the slower they go.
The patient may be treated by a number of therapists (osteos, physios, chiros), for a number of exotic sounding imbalances, but one thing remains constant; the symptoms persist. Oh, and they keep getting beaten by people who they used to beat easily, and we all know that’s what really hurts.
The Cardiologists amongst us have studied these arteries and their conclusion is that the irritation to the artery is clearly not related to arterial damage like arteriosclerosis, or atherosclerosis, associated with smoking and cholesterol. The arteries in the cyclist are physically irritated if you will, not chemically irritated (like in the pizza eating smoker), so it is a different process. Of course, cyclists who have smoked, eaten too many pizzas, or just got unlucky with their genes can also get arterial blockages unrelated to mechanical causes, just like a non-cyclist can.
A simple, but not always conclusive test the doctors perform is to exercise the patient, then take their blood pressure at their arm and at their ankle. In a normal patient these two measurements will be the same or similar. In the patient with the problem, the blood pressure in the ankle of the effected leg will be lower (because it is getting less blood).
More invasive tests may follow. The problem is that the condition is not common so you’ll need to see a Specialist familiar with cyclists and their injuries. Often it’s difficult to confirm with absolute certainty. This is important because the surgery carries significant risks so you really want to be sure that surgery is warranted. For example, symptoms can be very similar to nerve pains from the back, and you don’t want to discover after the surgery that you still have the problem, and that it was coming from your spine all along.
If you do the tests and it looks like you need a patch, the surgeons sharpen their scalpels. They will cut out the kinked bit and sew in a bit of vein from your leg; vascular surgeons use a ‘patch’ from a vein in your leg, because vein is a bit ‘flimsier’ than artery so it bends a bit better. Artery has a muscular wall – which is why it pulses, and makes a worse patch. You can ‘spare’ a bit of vein more than you can spare artery, and as a rule arteries run deep and are therefore harder to harvest. There are other vascular procedures, but they are done on the ‘vascularly unhealthy’ so to speak, and do not work well on athletes.
The return to the bike needs to be managed carefully, and has to be conducted under close medical supervision, but once it is done, a rider can perform at a high level again. Just ask Stuart O’Grady.
Many thanks to Dr Andrew Garnham ( Alphington Sports Medicine Clinic) for help in the writing of this article.