The purpose of this double blind, randomized and sham controlled study is to determine whether renal denervation in terms of catheter based ablation in the renal arteries is effective in lowering blood pressure in patients with treatment resistant hypertension. The blood pressure lowering effect will be evaluated by 24 hours ambulatory blood pressure measurement at baseline and after 1, 3 and 6 months of follow up. Secondary end point evaluation concerns hemodynamic measures using echocardiography, applanation tonometry and forearm plethysmography.