Atherosclerosis is the most common cause for an iliac artery flow limitation, typically in older patients. However, diminished perfusion of the leg may also occur in young,
otherwise healthy endurance athletes especially if they are engaged in cycling and ice speed skating. Flow limitations in the iliac artery (FLIA) in these athletes cause leg pain,
powerlessness, and/or cramps during (near) maximal effort.Some aspects of the pathophysiology of FLIA in these young endurance athletes are unveiled. Anatomically, the iliac artery is located ventral to the axis of rotation of the hip joint. Therefore, as the hip (hyper)flexes during these endurance sports activities, excess length of the iliac artery may ensue. The arterial structures can accommodate for this excess length with intrinsic longitudinal elasticity, or if this is insufficient by bending into increased tortuosity. If the artery is tethered to surrounding tissue (for instance, by side branches to the psoas muscle), this may limit the mobility of the artery to bend evenly and may trigger arterial kinking. Our group has previously postulated that such arterial kinking should be considered as ‘functional narrowing’. This narrowing leads to increased flow velocity and aggravates the local hemodynamic loading of the artery. As a reaction the vessel may maladapt resulting in: ’Endofibrosis’. We have proposed to define three types of FLIA, which likely overlap:

1. Arterial kinking in its pure form, without lengthening
2. Arterial kinking due to excessive lengthening
3. Elongated endofibrotic arterial stenosis

As complaints often worsen over time, delayed diagnosis might eventually result in an arterial occlusion. Unfortunately, current single diagnostic methods for FLIA lack
accuracy, resulting in over-reliance of multiple diagnostic tools. This thesis is divided into two parts. Part I reports on two techniques that are investigated for their potential to improve the diagnostic accuracy during a maximal effort exercise test. Part II deals with the surgical efficacy of three types of surgery tailored to the cause of FLIA (arterial release, arterial shortening, or a vascular reconstruction with closure using an autologous patch).