Arterial hypertension has many causes, which may be innate (the so called ‘essential’ arterial hypertension) as well as acquired causes.
One of the most important acquired factors which can lead to arterial hypertension is renal artery stenosis. The mechanism by which the narrowing of the renal artery lumen determines arterial hypertension is very complex – the decreased renal excretion of water and salt leads to the production by the kidney of certain substances that determine artery constriction.
Occurrence of hypertension at young ages (less than 30 yrs old) or arterial abdominal bruits are suggestive of a renal artery stenosis. Also, we may suspect the presence of renal artery stenosis in the case of therapy-resistant hypertension, recurrent episodes of cardiac decompensation, and hypertension associated with renal insufficiency.
The diagnosis is initially made by Doppler echocardiography of the renal arteries, which not only identifies the narrowing at this level, but also quantifies the hemodynamic consequences of the stenosis. For a more precise diagnosis, other non-invasive exams (contrast computed tomography, magnetic resonance imaging) or minimally-invasive exams (selective angiography of the renal arteries) can be made.
The goal in renal artery stenosis is the restoration of renal blood flow. Currently, most of the patients can be treated percutaneously by a minimally-invasive approach. The technique implies the positioning of a balloon in the renal artery at the level of the stenosed segment, which, after being inflated, compresses the stenosis, thus restoring the blood flow. The procedure can be completed by the placement of a stent, which maintains artery patency for a longer period of time. The procedure allows the improvement of symptoms, improvement of renal function, and a better control of arterial hypertension.