This study will use PBV technique to quantitatively assess the improvement of renal perfusion before and after endovascular treatment (EVT) of renal artery stenosis.

BACKGROUND: Renal artery stenosis (RAS) is one of the main reasons for secondary hypertension and renal failure, which etiologies include atherosclerosis, fibromuscular dysplasia and takayasu arteritis. Endovascular treatment under digital subtraction angiography (DSA) is an option to treat this disease. However, the technical success of this procedure is mainly based on morphology of its targeting renal artery without any quantified data towards renal blood perfusion. Thus, this study will try to solve how renal blood perfusion changes before and after endovascular treatment of renal artery stenosis.

DESIGN NARRATIVE:

This prospective cohort study will recruit patients with renal artery stenosis. PBV data will be obtained before and after their endovascular treatments. The volume of target kidney and its mean density of contrast from PBV data will be calculated as indicators for renal perfusion. And the relation between the percentage of stenosis and renal perfusion will be analyzed. The follow-up will last for one year. At 6-month and 12-month follow-up, DSA and PBV acquisition protocol will be undertaken again to evaluate renal blood perfusion in the long term.

Inclusion Criteria:

Patients should meet all of the following criteria:

1. Age ≥ 18.
2. Renal artery stenosis is greater than or equal to 80% and less than 100% by duplex, CT angiography or magnetic resonance angiography.
3. The target kidney remains functional(tested by radionuclide imaging)
4. Documented history of hypertension on two or more anti-hypertensive medications OR estimated glomerular filtration rate (eGFR) less than 60 mL per minute per 1.73 m^2, calculated by the modified Modification of Diet in Renal Disease formula.
5. The length of target kidney is >8cm.

Exclusion Criteria:

Patients meet any of the following criteria should be excluded.

1. Unable or willing to comply with study protocol or procedures.
2. Pregnancy or lactation.
3. History of kidney transplant.
4. Currently in acute pulmonary edema OR systolic ejection fraction of heart <30% OR respiratory failure due to hypertension or acute coronary syndrome or cerebrovascular accident in past 3 months.
5. The eGFR is less than 15 mL per minute per 1.73 m^2 OR serum Cr is greater than 3.0 mg/dl on the day of randomization.
6. Other known reason nonischemic kidney injure(e.g. nephritis). If it is diabetic nephropathy, 24h urinary protein should be more then 3g.
7. Aorta has stenosis(greater than 30%).

Consecutive patients who meet the inclusion criteria, are willing to join this trial and treated in the department of vascular surgery, Peking Union Medical College Hospital will be included in this prospective cohort study.