Purpose: To determine if angioplasty of atherosclerotic renal artery stenosis, which reduces the activation of the renin-angiotensin-aldosterone system (RAAS), may lead to regression of left ventricular hypertrophy. Methods: The study included 102 patients (58 men; mean age 67 years, range 66-69) who underwent stent-supported percutaneous transluminal renal angioplasty (PTRA) and were included in a clinical follow-up program (mean 24 14 months, range 6-60). As a control group, 101 contemporaneous patients (68 men; mean age 68 years, range 66-70) with essential hypertension were investigated. The primary endpoint was the change in left ventricular mass index (LVMI) determined by echocardiography. Results: Mean follow-up intervals were 24 +/- 14 months (range 6-60) in the study group and 27 +/- 14 months (range 6-60) in the controls (p=0.09). LVMI decreased significantly by -10 +/- 26 g/m(2) in the study group, while it increased significantly by 9 28 g/m(2) in the control group (p=0.001 between groups). In the study group, mean arterial blood pressure was significantly reduced from 99 +/- 11 mmHg to 90 +/- 11 mmHg (p<0.0001) during follow-up despite a significant reduction in medication, whereas it increased significantly from 102 +/- 11 mmHg to 105 +/- 11 mmHg (p=0.008) in the control group, although medication was significantly increased. After adjustment for various factors and covariables, PTRA prevailed as an independent predictor for regression of LVMI (p=0.038). Conclusion: PTRA induces regression of LVMI that is independent of the reduction in blood pressure induced by this procedure. Reduced activity of the RAAS may account for this regression.