Zainidip in Renal Artery Stenosis

Inclusion Criteria: * Age between 40 - 75 * Diameter of stenosis of renal artery or main branch of renal artery ≥60％. If diameter of stenosis is 60% - 75%, pressure difference between proximal and distal end ≥20 mm Hg (1mmHg=0.133kPa) or Captopril renography positive; * Systolic blood pressure before taking antihypertensive ≥180mmHg and/or diastolic blood pressure ≥110 mmHg; taking three antihypertensive including one diuretics with systolic blood pressure ≥140mmHg and/or ≥90 mmHg; * length of ipsilateral kidney is greater than 7.0cm. Exclusion Criteria: * Estimated glomerular filtration rate (eGFR) \<30 ml/ (min﹒1.73 m 2) \[eGFR (mL/min/1.73 m2) = 186.3 \* serum creatinine (mg/dl) -1.154 \* Age-0.203 \* 0.742 (female)\[11\]; * unstable condition and unable to tolerate interventional therapy; * anatomy of renal artery pathology not suitable for interventional therapy; * allergic to dihydropyridines; * III degree atrioventricular block * contrast allergy ; * any known malignant tumor; * non-compliant, history of alcoholism or drug abuse.