Renal Artery Disease
Renal artery disease is usually caused by atherosclerosis, hardening of the arteries due to the build-up of fatty deposits or plaques along the artery wall. This build-up can reduce blood-flow to one or both kidneys, or block flow completely, depending on the location of the plaque.
Renal artery disease can also be caused by fibromuscular dysplasia (FMD), a condition usually found in young women between the ages of 20 and 40. FMD results in the overgrowth of tissue inside the artery in a characteristic “chain of beads” pattern. This condition can affect other arteries, as well.
Renal artery disease can result in:
- Renovascular hypertension
- Renal insufficiency
Renovascular hypertension is high blood pressure (greater than 140/80 mmHg) caused by renal artery disease. Normally, the kidneys regulate body fluid and blood pressure, as well as regulate blood chemistry and remove organic waste. Proper kidney function is disrupted, however, when the arteries that provide blood to the kidneys become narrowed, a condition called renal artery stenosis. When stenosis results in reduced blood-flow, the kidney compensates by producing hormones that increase blood pressure. This response is a healthy one under normal circumstances. But when the reduction in blood-flow is due to stenosis, blood pressure is increased unnecessarily. High blood pressure caused by renal artery disease may be difficult to control with medication. The good news is that renovascular hypertension is one of the few identifiable and treatable causes of high blood pressure — a condition that, if left untreated, can lead to heart attack, stroke or kidney failure.
Primary hypertension is high blood pressure that has no apparent cause. Renovascular hypertension is the most common cause of secondary hypertension, high blood pressure that can be attributed to a specific cause. It is responsible for about 1 percent to 2 percent of the 50 million estimated cases of hypertension in the United States.
Clues that high blood pressure is being caused by renal artery stenosis include:
- Significant high blood pressure at a young age
- Stable hypertension that suddenly gets worse
- High blood pressure that occurs with impaired renal function
- High blood pressure in someone with an abdominal aortic aneurysm or disease of the coronary, carotid or the lower extremity arteries
Patients who have atherosclerosis in some other part of the body are 30 percent to 50 percent more likely to develop renal artery stenosis.
Renovascular disease can usually be diagnosed via duplex ultrasound scanning and other non-invasive tests. These include CT angiography and MR angiography.
The most common treatment for renovascular hypertension caused by renal artery stenosis is balloon angioplasty to open the artery followed by stent placement to keep it open. Renal insufficiency is poor function of the kidneys that may be due to a reduction in blood-flow to the kidneys caused by renal artery disease. Normally, the kidneys regulate body fluid and blood pressure, as well as regulate blood chemistry and remove organic waste. Proper kidney function may be disrupted, however, when the arteries that provide the kidneys with blood become narrowed, a condition called renal artery stenosis. Some patients with renal insufficiency experience no symptoms or only mild symptoms. Others develop dangerously high blood pressure, poor kidney function, or kidney failure that requires dialysis.
Risk Factors for renal insufficiency due to renal artery disease are those associated with atherosclerosis:
- Older age
- Family history
- Race or ethnicity
- Genetic factors
- Hyperlipidemia (elevated fats in the blood)
- Hypertension (high blood pressure)
Patients known to have atherosclerosis and diagnosed with coronary artery disease or peripheral artery disease are at greater risk for renal insufficiency.