This study is conducted to investigate the short-term safety and preliminary efficacy of stereotactic radiotherapy for renal denervation to treat refractory hypertension.

This will be a single centre, single arm, prospective cohort study. Patients with refractory hypertension will receive single fraction stereotactic radiotherapy for renal denervation. The study has been designed in a careful and stepwise dose escalation fashion in order to minimize the potential risks associated with this innovative technique. The dose escalation is guided by 3+3 algorithm to ensure more patients will be spared dose limiting toxicities and more patients will be entered on the dose level that will be chosen as optimal dose of maximal effect. Low dosing levels with established safety profile will first be applied before administering higher dosing levels based on preclinical studies.

Safety is the primary endpoint of this study. Safety will be assessed by incidence and evaluation of any serious adverse events using CTCAE v5.0 criteria associated with the procedure through 90 days. Efficacy will be evaluated by assessing mean reduction in average 24-hour ambulatory blood pressure at 90 days post-treatment.

Inclusion Criteria:

Age ≥ 55 and ≤ 75 years. Systolic blood pressure of 160 mmHg or greater despite being treated with at least three hypertensive drugs for more than 3 months.

Exclusion Criteria:

GFR < 45 ml/min/1.73 m2. Known causes of secondary hypertension. Hospitalized for hypertensive crisis within 1 year. History of acute coronary syndrome or cerebrovascular accident within the last 6 months.

Pregnancy or have a pregnancy plan. Contrast media or iodine allergy. History of abdominal radiotherapy or adhesive intestinal obstruction. Severe valvular heart disease. Stenosis >50% or renal artery aneurysm in either renal artery. Others.