Then patients are given trandolapril 2 mg once a day as a single dose in open conditions for four weeks. At the end of this period they are randomly assigned to receive once a day, in a double-blind fashion, either trandolapril 2 mg combined with verapamil 180 mg plus a placebo, or trandolapril 2 mg plus amlodipine 5 mg. Patients are monitored after one, two, five and eight months. When renal artery stenosis is clinically suspected, patients are examined by Doppler ultrasound or renal scintigraphy. The diet will remain unchanged throughout the trial.
Randomization is centralized using a list, divided into blocks of four.
A 12-month recruitment period is estimated. Study procedures Patients are instructed to take study drugs each day in the morning on awaking. They are to be examined at baseline, after one, two, five and eight months. At each visit they are asked about their clinical symptoms, possible adverse events of treatment and drug compliance. Physical examination, including measurement of body weight and blood pressure, is done between 8 and 10 a.m. Blood pressure is measured by the same observer in the dominant arm using a standard sphygmomanometer, with the patient sitting in a quiet room for at least ten minutes.