Renal Artery Stenosis

Overview

Renal artery stenosis occurs when one or more arteries supplying blood to the kidneys become narrowed. This constriction restricts the flow of oxygen-rich blood to the kidneys, which is essential for their proper function in filtering waste and regulating fluid levels in the body. Reduced blood flow can result in kidney tissue damage and elevated blood pressure throughout the body.

Symptoms

Renal artery stenosis frequently remains asymptomatic until it reaches an advanced stage. Often, the condition is detected incidentally during tests conducted for unrelated reasons. Additionally, your doctor may suspect an issue if you experience:

• Elevated blood pressure that starts unexpectedly or becomes worse on its own
• Elevated blood pressure that starts before 30 or beyond 50

Other signs and symptoms that may appear when renal artery stenosis worsens include:

• Fatigue
• Loss of appetite
• Nausea and vomiting
• Muscle cramps
• Headache
• Difficulty breathing
• Changes in urination frequency (either more or less often)
• Elevated protein levels in the urine or other signs of a kidney problem
• A worsening kidney function while you are receiving treatment for high blood pressure
• An excess of fluid and edema in the tissues of your body
• A heart failure resistant to treatment
• Difficulty controlling high blood pressure
• Alterations in the skin, like dry, itchy, or discolored (darker) skin
• A whooshing sound made by blood passing through a narrowed vessel (bruit), which your doctor can hear through a stethoscope placed over your kidneys

If you observe any ongoing signs or symptoms that worry you, it’s advisable to arrange an appointment with your doctor.

Causes

The primary culprits behind renal artery stenosis are:

• Buildup on renal arteries. Lipids, cholesterol, and other materials (plaque) have the potential to accumulate within and on the walls of your renal arteries, a condition known as atherosclerosis. Over time, these deposits may grow, solidify, impede blood flow, lead to kidney scarring, and ultimately result in artery narrowing. Atherosclerosis can develop in various regions of the body and stands as the primary cause of renal artery stenosis.
• Fibromuscular dysplasia. Fibromuscular dysplasia involves abnormal growth of the muscle within the artery wall, which typically initiates during childhood. In this condition, the renal artery may exhibit narrow segments interspersed with wider sections, creating a bead-like appearance in artery images. When the renal artery narrows significantly, the kidney may not receive adequate blood supply, potentially triggering early-onset hypertension. This can affect one or both kidneys. The precise cause of fibromuscular dysplasia remains unclear, although it appears to be more prevalent in women and may be congenital, possibly present from birth. Constrictions in the kidney arteries and fibromuscular dysplasia can affect not only the renal arteries but also other arteries in the body, leading to complications.

Occasionally, renal artery stenosis may develop due to other conditions, such as vascular inflammation or the growth of abdominal masses that compress the arteries supplying the kidneys.

Risk factors

The primary cause of renal artery stenosis is narrowed kidney arteries. Risk factors that increase the likelihood of narrowed arteries affecting your kidneys and other areas of your body include:

• Aging
• Obesity
• Diabetes
• High blood pressure
• High cholesterol
• Lack of exercise
• Early heart disease in the family
• Using tobacco products and smoking