Renovascular conditions are disorders or diseases affecting the blood vessels of the kidneys. Typically, renovascular conditions involve either narrowing of the kidney arteries or blockage of the kidney veins. Atherosclerosis, the accumulation of cholesterol and other fats along the lining of artery walls, is a main contributor to renovascular conditions.
Renovascular hypertension, high blood pressure, is caused by narrowing of the arteries that carry blood to the kidneys.
Renovascular hypertension is a form of secondary hypertension. Most forms of hypertension are considered "essential," and the cause is unknown. But a small number of high blood pressure patients have "secondary hypertension," which means an underlying disease is identified as the cause.
During renovascular hypertension, one or both of the kidney arteries become narrow. This reduces blood flow to the kidneys, and the affected kidney or kidneys mistakenly respond as if the patient's blood pressure is low. They secrete hormones that tell the body to retain salt and water. This causes an increase in blood pressure.
Two groups of patients are at particular risk for this: young women with a sudden onset of high blood pressure and older people with atherosclerosis (narrowing) in other arteries, such as the heart (coronary artery disease) or the legs (peripheral vascular disease).
Renal duplex, a sophisticated ultrasound technique, aids in the diagnosis of patients with renal artery stenosis. This noninvasive technology is useful in selecting patients for further evaluation and possible treatment. Renovascular hypertension often can be treated with angioplasty and/or stenting of the narrowed artery.
TREATMENT
Renal (Kidney) Angiography
Angiography is an exam of the arteries and veins to diagnose blockages and other blood vessel problems. An interventional radiologist performs this procedure, also called an angiogram or venogram, on an out-patient basis. During the angiogram, the doctor inserts a thin tube (catheter) into the artery through a small incision in the skin. A substance called a contrast agent (X-ray dye) is injected to make the blood vessels visible on the X-ray. One of the most common reasons for angiography is to see if there is a blockage or narrowing in a blood vessel that may interfere with the normal flow of blood through the body. In many cases, the interventional radiologist can treat a blocked blood vessel without surgery at the same time the angiogram is performed using techniques called angioplasty and thrombolysis.
Renal Artery Balloon Angioplasty and Stent Placement
Angioplasty is a technique for opening up narrowed blood vessels, such as in the legs or the neck. A very small balloon attached to a thin tube (catheter) is inserted into a blood vessel through a small nick in the skin. The catheter is threaded under X-ray guidance to the site of the narrowed artery. The balloon is inflated to open the artery. Sometimes, a small metal scaffold called a stent is also inserted to hold the blood vessel open. Angioplasty and stents often replace by-pass graft surgery in treating artery problems. |
