Renal Denervation in Patients With Refractory Hypertension

Inclusion Criteria: * \>= 18 years of age. * a systolic blood pressure of 160 mmHg or greater. * receiving and adhering to full doses of an appropriate antihypertensive drug regimen for a minimum of two weeks prior to screening. * agrees to have the study procedure(s) performed and additional procedures and evaluations, including repeat phlebotomy, imaging, urine analyses, and clinical examination. * competent and willing to provide written, informed consent to participate in this clinical study. Exclusion Criteria: * renal arterial abnormalities * end stage renal disease requiring dialysis or renal transplant * serum Cr \> 3, or calculated GFR \< 45 ml/min * has experienced MI, unstable angina pectoris, or CVA with 6 months * others