Can opening blocked kidney arteries tame stubborn high blood pressure?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Eligibility criteria 1. True resistant hypertension (≥ 3 antihypertensive drugs including a diuretic, if tolerated, and each prescribed at optimal doses) and uncontrolled blood pressure confirmed by 24-hour ambulatory blood pressure monitoring. The 24-hour ambulatory blood pressure monitoring is performed after nurse-administered medication and blood pressure measurements are performed hourly. If the average 24-hour ambulatory systolic blood pressure is ≥ 130 mmHg the patient can be evaluated for renal artery stenosis. 2. Hypertension and intolerance or side effects of the antihypertensive treatment. Hypertension is confirmed by 24-hour ambulatory blood pressure monitoring. The 24-hour ambulatory blood pressure monitoring is performed after nurse-administered medication and blood pressure measurements are performed hourly. If the average 24-hour ambulatory systolic blood pressure is ≥ 130 mmHg the patient can be evaluated for renal artery stenosis. 3. Progressive renal insufficiency (a reduction in eGFR \> 5 ml/min/1,73 m2 per year) in patients with bilateral renal artery stenosis or in patients with renal artery stenosis and only one kidney. 4. Recurrent heart failure/pulmonary edema and resistant hypertension (≥ 3 antihypertensive drugs including a diuretic, if tolerated, and each prescribed at optimal doses) that may not be attributed to non-compliance, reduced left heart ventricular ejection fraction/heart valve disease or other obvious explanations (atrial fibrillation, fever, hyperthyroidism etc.). If the average 24-hour ambulatory systolic blood pressure is ≥ 130 mmHg after nurse-administered medication the patient can be evaluated for renal artery stenosis. 5. Younger patients (\< 40 years) with hypertension (24-hour ambulatory blood pressure monitoring ≥ 130/80 mmHg after nurse-administered medication ) Inclusion Criteria: All of the following: 1. At least one of the above eligibility criteria 2. Duplex doppler ultrasonography or renography investigations consistent with hemodynamically significant renal artery stenosis 3. CT angiography or renal arteriography with angiographic renal artery stenosis of ≥ 70 % reduction of the luminal diameter in at least one projection Exclusion Criteria: 1. If angiography/arteriography, ultrasonography or renography is consistent with bilateral significant renal artery stenosis and only one side is treated with PTRA 2. PTRA of a renal artery supplying a kidney which pre-PTRA handles ≤ 10% of the total kidney function (with no blockage of the renin-angiotensin system) and has a kidney size \< 7 cm (length)