Fractional Flow Reserve-guided Stenting Versus Medical Therapy in Atherosclerosis Renal Artery Stenosis

Fractional Flow Reserve-guided Percutaneous Renal Artery Stenting Plus Optimal Medical Therapy Versus Optimal Medical Therapy Alone In Atherosclerosis Renal-vascular Hypertension Patients: a Multicenter Randomized Trial

Although randomized trials have demonstrated there is no benefit of renal-artery stenting in addition to medical therapy for patients with atherosclerosis renal artery stenosis, many patients indeed gained benefit in daily practices after stenting, such as reduction in blood pressure and recovery in renal functions. One important gap is that there is no universal standard to determine whether to stent in these patients. Fraction Flow Reserve (FFR) has been studied for many year in chronic coronary heart disease and FFR-guided revascularization strategy is known to be better than both angiography-guided revascularization and medication alone. Based on the primary finding of FAIR-pilot study (NCT05732077), FFR-guided renal artery stenting is practical.

The overall purpose of the FAIR trial is to compare the clinical outcomes and safety of FFR-guided stenting plus optimal medical treatment (OMT) versus OMT alone in patients with renal-vascular hypertensive patients.

With the 'all comers' design, participants met the inclusive/exclusive criteria will be enrolled, and hyperemic FFR induced by dopamine will be measured in all participants. If FFR is ≥0.80, patients will be treated with OMT alone and follow up. If FFR is <0.80, participants will be randomized to stenting in the renal artery plus OMT or OMT alone on a 1:1 ratio. The blood pressure and anti-hypertensive medications will be compared before and 3 months after the procedure based on ambulatory blood pressure monitoring, all participants will be followed up for 1 year.

Inclusion Criteria:

• With recorded hypertension, AND the blood pressure is not controlled (daytime mean SBP ≥135 mmHg and/or DBP ≥85 mmHg based on ABPM) on 2 or more classes of anti-hypertensive drugs;
• Evidence of renal artery stenosis and undergoing renal artery angiography;
• Able to follow the study protocol and provide informed consent;
• Renal artery angiography shows at least 1 main artery with stenosis of 50%-90%, AND the diameter is ≥ 4.0mm.

Exclusion Criteria:

• SBP ≥200mmHg and/or DBP ≥120mmHg at the day or randomization;
• Fibromuscular dysplasia or other non-atherosclerotic renal artery stenosis;
• Pregnancy or unknown pregnancy status in female of childbearing potential;
• Participation in any drug or device trial during the study period;
• Any stroke/TIA, OR with ≥70% stenosis of carotid artery;
• Any major surgery, myocardial infarction or interventional therapy 30 days prior to study entry;
• LVEF <30%;
• Comorbidity condition causing life expectancy ≤1 year;
• Allergy to contrast or any of the following: aspirin, clopidogrel;
• Previous kidney transplant;
• Previous renal artery bypass surgery or stent intervention;
• Kidney size less than 8 cm measured by ultrasound;
• Local lab serum Cr >3.0 mg/dl (265.2μmol/l) on the day of randomization;
• Reference vessel size <4 mm or >8 mm.