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Pain and powerless feeling in the leg during cycling may indicate a serious problem that limits the performance in cyclists. Apart from the well-known muscular and neurological origin, such complaints can also be attributed to flow limitations in the iliac arteries caused by functional lesions (kinking and/or excessive length of vessels) and/or intravascular lesions (endofibrosis). Reliable insight in the prevalence is lacking. Most intravascular lesions (approximately 90%) are located in the external iliac artery. The diagnosis is frequently missed because physiotherapists and medical doctors are often unacquainted with the problem. The only finding in physical examination, discriminating for a vascular problem, is a bruit in the inguinal region with the thigh maximally flexed. Available diagnostic techniques are proven to be inadequate for this specific lesion, which has characteristics other than those of atherosclerotic lesions. Moreover, common techniques in a vascular laboratory do not incorporate the specific sport conditions necessary for provoking the complaints. Provocative testing on a bicycle ergometer with high intensity of exercise, combined with postexercise blood pressure measurements (at the ankle of both legs, or the ankle to arm pressure ratio) is used. Imaging techniques (echo-doppler, arterial digital subtraction angiography, magnetic resonance imaging and angiography) are necessary for proper classification of the problem. The application of specific provoking manoeuvres (hip flexion, psoas contraction, high-intensity exercise) in combination with these imaging techniques prove to be potentially valuable, although the diagnostic accuracy has to be established. Treatment should be tailored to the specific problems of the individual patient. Conservative treatment mainly indicates an advice to change sports activity. Surgical mobilization of the iliac arteries for functional lesions, and vascular reconstructions in case of intravascular lesions are possible, although long-term follow-up is lacking. Percutaneous transluminal angioplasty and intravascular stent are contra-indicated because of high risks for dissection and reactive intimal hyperplasia, respectively.

Flow limitations in the iliac arteries of endurance athletes during exercise were previously ascribed solely to intravascular lesions. We postulate that functional kinking of the arteries can also result in flow limitations. However, the diagnostic tools in routine practice are not effective in diagnosing such flow limitations in a substantial proportion of athletes, mainly because these diagnostic tools do not measure in the provocative situations. Ninety-two symptomatic legs in 80 endurance athletes were examined with newly developed, sports-specific vascular tests. Thirty-five asymptomatic cyclists matched for working capacity served as the control subjects. Legs were classified as vascular or non-vascular following a decision algorithm, based upon the results of these diagnostic tests, excluding orthopaedic causes by the effects of specific treatment. Independently of this clinical classification, an alternative method was applied to find stable characteristics in the total patient group using factor analysis. This characterisation was based on scores on 14 test variables deriving from diagnostic tests that were not used in the decision algorithm, thus avoiding dependency between the clinical categorisation and the statistical categorisation. The hypothesis was that these characteristics were sufficiently sensitive to classify patients with vascular and non-vascular complaints. If so, these characteristics should correspond with the one derived from the decision algorithm. Following the decision algorithm, 58 legs (63%) were classified as vascular, 29 (32%) as non-vascular and 5 (5%) as inconclusive. The latter were considered non-vascular. In a substantial proportion of the vascular patients, kinking of the iliac arteries was identified as the major cause of flow limitation. The characteristics derived from factor analysis proved to classify 87% in agreement with the decision algorithm (kappa 0.56). The agreement is sufficient for validation of the clinical classification. The algorithm can therefore be applied in clinical situations to diagnose endurance athletes with flow limitations due to both intravascular lesions and kinking of the arteries.

simple sports-specific tests accurately diagnose iliac artery obstruction in endurance athletes.

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