Renal Artery Stenosis (RAS)
Narrowing of one or both arteries of the kidney is a condition called renal artery stenosis (RAS). The most common cause of RAS is atherosclerosis, in which fatty materials are deposited along the arteries' interior walls, restricting blood blow to the kidney. Lacking sufficient blood supply triggers the kidney to "think" that the body's blood pressure is too low, and it secretes a hormone called Renin, which causes the body to retain salt and water, resulting in hypertension (high blood pressure). Approximately 5% of people with high blood pressure can attribute their condition to RAS. RAS can also cause progressive kidney failure and pulmonary edema (fluid in the lungs).
Signs of Renal Artery Stenosis:
Deterioration of kidney function
Elevated blood pressure unresolved with oral medications
Sudden worsening of hypertension previously well-controlled
The diagnosis of renal artery stenosis can be made using a combination of:
Computed Tomographic (CT) Angiography
Duplex ultrasound imaging
Magnetic Resonance Angiography (MRA)
Radionuclide renal scanning
Many lesions can be fixed using minimally invasive angioplasty and stent placement.
Other narrowings require more invasive surgical reconstruction for optimal results.
Restoring normal blood flow to the kidneys may lower the blood pressure, preserve renal function and decrease the risk of pulmonary edema.
Following stenting, 30-60% of patients experience improved blood pressure control, often requiring fewer medications. Renal function is improved in a smaller percentage of patients.