The renal arteries normally arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle with the aorta. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. The arterial supply of the kidneys is variable and there may be one or more renal arteries supplying each kidney. It is located above the renal vein. Supernumerary renal arteries(two or more arteries to a single kidney) are the most common renovascular anomaly, occurrence ranging from 25% to 40% of kidneys.
Some forms of hypertension may be related to renal artery narrowing (stenosis). However, renal caused hypertension seems to be more related to disease of the smaller arteries within the kidney that are too small for treatment. There is some evidence to suggest that treating narrowing of the main renal arteries secondary to atherosclerosis may reduce the number of medications required to control hypertension or reduce overall hypertension. The current literature, however, is controversial.