Renal artery stenosis is a renal vascular lesion in which the lumen of the renal artery narrows and renal blood flow decreases due to various causes. There are many causes, with aortitis and renal artery myofibrillar dysplasia being the most common in young people in China and atherosclerosis being the most common in older people. Other rare causes such as renal artery thromboembolism, arteriovenous fistula, and aneurysm can also lead to renal artery stenosis. Stenosis of the renal artery anastomosis after transplantation or surgery is also considered renal artery stenosis. The clinical manifestations are mainly hypertension and renal insufficiency. Headache, dizziness, palpitations, nausea, and blurred vision, etc. A few patients present with aldosteronism, such as hypokalemia and hypertension. Prolonged renal ischemia may lead to renal atrophy and renal insufficiency. On examination, a rough vascular murmur may be heard in the upper abdomen or renal area. Diagnostic points When renal artery stenosis is clinically suspected, intravenous pyelogram, radionuclide renal dynamic imaging, ultrasound, CT angiography, MRA and angiography can be performed. Ultrasound is convenient, non-invasive and economical. 2D ultrasound can show the size, shape and internal echo of the kidney, while color Doppler ultrasound can further show the lumen of the renal artery and measure blood flow velocity, resistance index and other indicators to diagnose stenosis and evaluate the degree of stenosis, which is the first choice for screening. CT angiography can clearly show the renal artery, especially in showing the collateral renal artery and vascular calcification, which has obvious advantages over ultrasound. CT can simultaneously scan other abdominal organs, such as the adrenal glands. if the renal arteries are normal but the adrenal glands are occupied, hypertension caused by adrenal pheochromocytoma should be suspected. MR and CT angiography can also obtain clear vascular images, and the former does not use iodine-containing contrast agents, reducing nephrotoxicity and making it more suitable for patients with renal insufficiency. Renal arteriography has been considered the gold standard for the diagnosis of renal artery stenosis, which can clarify the presence or absence of renal artery stenosis, as well as the site, degree, extent and etiology of stenosis, and can be accompanied by interventional treatment. Treatment options Internal treatment is mainly antihypertensive treatment, and many patients have unsatisfactory effect of drug antihypertensive treatment. For surgical treatment, nephrectomy and autologous kidney transplantation are available. In recent years, percutaneous intracavernous angioplasty of the renal artery has become the preferred alternative to surgical renal artery reconstruction because of its small trauma, clear effect and mature technology. Long-term hypertension is prone to cardiac, cerebral and renal complications, and long-term renal ischemia can also lead to renal insufficiency and renal failure, so patients with recent renal decompensation and elevated blood creatinine should be treated more actively. The method is to deliver a balloon catheter via femoral artery puncture into the renal artery stenosis and then dilate or place a stent to restore the renal artery lumen and blood flow to normal. This treatment is effective in lowering blood pressure in most patients, and in some patients it also improves renal function. The technical success rate of renal artery balloon dilation with renal artery stenting is 90-100%. more than 70-80% of patients have varying degrees of postoperative blood pressure reduction. Studies reporting improvements in renal function vary widely, ranging from 30 to 70%. Stenting of the renal artery has been found to be more effective and durable than balloon dilation alone, but is more costly. Etiology varies, with myofibrillar dysplasia being the most effective, atherosclerosis the second most effective, and aortitis the least effective. Complications and management The incidence of complications is about 1-5%. In addition to general angiographic complications such as bleeding or hematoma at the puncture site, there are complications due to balloon dilation or stent placement, such as local arterial entrapment; acute renal artery thrombosis; atherosclerotic plaque detachment leading to renal infarction; renal artery rupture and bleeding; stent displacement; restenosis and so on. Most of the complications are mild and can be cured by conservative treatment, such as thrombolysis by catheter in acute renal artery thrombosis; the use of distal umbrella of renal artery can prevent the occurrence of renal infarction; local entrapment can be solved by stent placement. Serious complications such as renal artery rupture are less common and require surgical treatment. Distant complications are mainly restenosis, of which myofibrillar dysplasia is the least common. The 5-year restenosis incidence of atherosclerosis is about 10-20%, and the restenosis incidence of aortitis is higher, up to 30-50% at 5 years. In patients with restenosis can be resolved by balloon dilation again.