[Renal artery stenosis. Pathophysiology--diagnosis--therapy].

Renal artery stenosis (RAS) is both a common and progressive disease and its prevalence in patients > 65 years is 6.8%. In patients with known or suspected atherosclerosis undergoing coronary angiography, a frequency of even 11-23% is reported in the literature. Despite this high prevalence, there is an ongoing discussion about the indications for revascularization and it is currently unclear, whether renal artery revascularization reduces adverse cardiovascular and renal events. Nevertheless, the number of interventions for RAS is rising steadily, although up to 40% of patients do not profit from this intervention. This fact underlines the necessity of a thorough diagnostic work-up before intervention, integrating morphological and functional tests. For morphological evaluation, multislice computed tomography, magnetic resonance tomography or digital subtraction angiography can be done. In experienced centers, Doppler ultrasound can serve as an excellent functional tool, to assess the physiological relevance of an RAS, but also invasive measurements of pressure and flow provide valuable information about the significance of stenoses; however, these methods will have to be assessed with respect to their value to predict long-term outcome. Although percutaneous intervention of RAS is associated with a substantially lower risk of major adverse events as compared to surgery, by using contrast media this procedure holds the risk of deterioration of renal function and of a small number of procedure-dependent complications as well. Thus, a careful consideration of pros and cons of this procedure is mandatory.