159-a : STENOSE ARTERY ILIACA IN CYCLISTS

Part 1: introduction

AN OCCUPATIONAL DISEASE FOR CYCLISTS

In the late 80’s doctors came to know a disease of the iliaca artery that occurs only at high level cyclists. In that case, there occurs a narrowing in a blood vessel, the iliac artery, causing that the blood flow to the leg, especially during intense cycling, such as a time trail or riding uphill, is severely limited. The typical complaints which arise doing so are: a heavy lame, tired, powerless feeling in the leg, which usually occurs unilaterally. The symptoms are so severe that the rider is not able to maintain the high level of exertion.

There are a number of mechanisms that play a role in the development of this profession threatening condition:

THE POSITION ON THE BIKE

The riding position on the bike is a key factor because the riding position is decisive for the hip angle. When one sits upright the hip angle, while cycling, remains fairly blunt. In an aerodynamic position that you see in extreme forms in cycling the hip angle is sharp or very sharp while cycling.

Hip angle in time trial                               and in skating

THE LENGTH OF THE ILIACA ARTERY

The longer the femoral artery, the greater the chance of the occurrence of a stenosis. A long artery iliaca winds and often develops kinks thereby seriously impeding blood flow to the leg by flexing the hip with each pedal revolution. This kinking phenomena is similar to the kinking of a garden hose to stop the water if one is too lazy to close the faucet.

THE NUMBER OF KILOMETERS COVERED

The abnormality is found in cyclists who have more than 50,000 kilometers by bike in the legs. Sometimes the complaint presents after 50,000 km and others only after 100,000 km.

THICKENING OF THE VASCULAR WALL

Thickening of the vascular wall results in a reduction of the diameter of the femoral artery up to 80 percent. This thickening of the vessel wall occurs at the place where the blood vessel always kinks. When one realizes that the femoral artery at a distance of 50,000 km will be kinked approximately 1.1 billion times and at 100,000 km the double number of times one can imagine that the wall of the blood vessel altogether gets a huge blow. In response, the vessel wall thickens in a given layer namely the intima. At that place scar tissue forms, this even further narrowed the lumen of the vessel.

From all these mechanisms, it follows that a surgical operation is a combination of the shortening of the long blood vessel plus the removal of the bulges in the artery wall.

THE DIAGNOSIS

should be made following the typical pattern of complaints and a number of specific investigations. This involves the objectification of a difference in the bloodstream, a difference in power and the difference in blood pressure between the good and the bad leg during maximal exercise testing.

THE TREATMENT

Is surgical in which different procedures are possible.