Renal artery stenosis can cause hypertension (newly emerged hypertension, or progressively worsening of original hypertension), reduced kidney function, recurrent acute pulmonary edema, proteinuria and renal atrophy etc. However, many patients do not have any symptoms. More importantly, renal artery stenosis is also a common cause that induces or aggravates renal failure. As the kidney dysfunction caused by renal artery stenosis can often be reversed after the stenosis has been corrected, it is very important to discover the problem early and choose an appropriate treatment method.