[Renovascular hypertension: is it only the top of the iceberg?]

Essential hypertension accounts for 95% of all cases of hypertension. A small number of patients (between 2% and 5%) have a reversible disease as the cause for raised blood pressure. Unilateral and bilateral renal artery stenosis may be responsible for secondary hypertension. Diagnosis and treatment of renal artery stenosis are of a great importance. Revascularization of ischemic kidney may correct blood pressure control and preserve renal function. Much data suggest close pathophysiological relation between renal artery stenosis, ischemic nephropathy and development of hypertension. However, it should be stressed that not every renal artery stenosis leads to hypertension and ischemic nephropathy. Therefore diagnosis of renal artery stenosis in hypertensive patient is not always equivalent with renovascular hypertension. The true prevalence of renal artery stenosis is unknown. In unselected population it accounts for less than 1% of hypertensive patients. Renovascular etiology of hypertension may be suggested by abrupt onset of hypertension, resistant and malignant hypertension or recurrent pulmonary edema of unknown etiology. Physical examination may reveal bruits over major vessels, including the abdominal aorta and renal arteries. The principle aim of the renal artery stenosis investigation is to confirm presence and size of vessel obstruction and its association with hypertension. Typical evaluation is based on imaging techniques and physiological studies. Former include: doppler duplex ultrasonography, conventional angiography, intraarterial and intravenous digital subtraction angiography, computed axial tomography, magnetic resonance angiography and intravascular ultrasonography. Functional studies are occasionally used. These are renal scintigraphy, evaluation of plasma renin activity in renal veins and evaluation of plasma rennin activity after ACE inhibition. Treatment of patients with renal artery stenosis and hypertension should restore vessel patency and inhibit its occlusion. Revascularization should elicit an improvement in or normalization of blood pressure control and renal function. Therapeutic approach include percutaneous renal artery angioplasty (PTRA), with or without stenting, revascularization by surgery and pharmacotherapy. PTRA is currently the first choice option. In general, it is simpler and similarly effective as surgical reconstruction. In some cases PTRA is completed with stent placement. It prevents immediate recoil but does not completely eliminate restenosis of revascularized artery. Surgical bypass is currently reserved for patients in whom PTRA and stenting fail and in patients with extensive atherosclerotic lesions. Patients with renal artery stenosis and hypertension should be provided with pharmacological treatment according to current recommendations. Specific procedures to limit associated risk factors of atherosclerosis should also be introduced.