Renal Artery Stenosis – Symptoms and Causes
Overview
Renal artery stenosis happens when the blood vessels that supply your kidneys become narrow. This narrowing blocks proper blood flow to the kidneys. The kidneys need a steady supply of oxygen-rich blood to work correctly.
When your kidneys don’t get enough blood, two main problems can occur:
- Kidney damage – tissues in the kidneys can become injured.
- High blood pressure – the body’s response to reduced kidney function.
The kidneys play a vital role in filtering waste and managing fluid levels in your body. When blood flow decreases, these important functions can be affected.
Signs and Warning Signs
Renal artery stenosis typically develops without noticeable signs until it reaches an advanced stage. The condition is often found accidentally during tests for other health issues.
Some possible indicators include:
- Sudden or unexplained worsening of high blood pressure
- High blood pressure starting before age 30 or after age 50
- Difficult-to-control high blood pressure
As the condition advances, you might experience:
- A “whooshing” sound (bruit) that doctors can hear through a stethoscope over your kidneys
- Higher protein levels in urine samples
- Declining kidney function, especially during high blood pressure treatment
- Swelling in body tissues due to fluid buildup
- Heart failure that doesn’t respond well to treatment
When You Should Get Medical Help
If you notice any ongoing symptoms that concern you, schedule an appointment with your doctor. Don’t ignore warning signs, especially those related to blood pressure changes or swelling. Early detection can help manage the condition more effectively.
Causes
Renal artery stenosis happens when the blood vessels leading to the kidneys become narrow. Two main factors typically cause this condition:
Atherosclerosis (Plaque Buildup)
- Fatty deposits accumulate on kidney artery walls
- Plaque hardens over time and narrows blood passages
- Reduces blood flow to kidneys
- Can lead to kidney scarring
- Most common cause of renal artery stenosis
Fibromuscular Dysplasia (FMD)
- Abnormal growth of muscle cells in artery walls
- Often begins during childhood
- Creates a distinctive “string of beads” pattern in affected arteries
- Can affect one or both kidneys
- More common in women than men
- May be present from birth
Fibromuscular dysplasia reduces blood flow to the kidneys, which can trigger high blood pressure at a young age. This condition can affect other blood vessels in the body besides the kidney arteries.
In rare cases, other conditions may cause renal artery stenosis. Blood vessel inflammation or growths in the abdomen that press against kidney arteries can lead to narrowing. These less common causes still produce the same effectโreduced blood flow to the kidneys.
The narrowing of kidney arteries, regardless of cause, leads to decreased kidney function and often results in high blood pressure that’s difficult to control with standard treatments.
Risk Factors
Several factors can increase your chance of developing narrowed kidney arteries:
- Age
- High blood pressure
- High cholesterol levels
- Diabetes
- Being overweight
- Using tobacco products
- Family history of early heart disease
- Sedentary lifestyle
These risk factors can affect blood vessels throughout your body, not just in your kidneys.
Complications
Renal artery stenosis can lead to several serious health issues if not properly managed. These complications can affect both kidney function and overall health.
High Blood Pressure
One of the most common complications is persistent high blood pressure that may be difficult to control with standard medications. This occurs because the narrowed artery triggers the kidney to release hormones that raise blood pressure.
Kidney Damage
When blood flow to the kidneys is reduced for an extended period, kidney tissues can become damaged. In severe cases, this may progress to kidney failure, which requires treatment with:
- Dialysis (artificial filtering of blood)
- Kidney transplant
Fluid Retention
Poor kidney function can lead to the body’s inability to remove excess fluid properly. This often appears as:
- Swelling in the ankles and feet
- Puffy appearance in the legs
- Weight gain due to excess fluid
Pulmonary Edema
In some cases, fluid can build up suddenly in the lungs, a condition called pulmonary edema. This serious complication causes:
- Shortness of breath
- Difficulty breathing, especially when lying down
- Feelings of suffocation or drowning
- Coughing, sometimes with frothy sputum
Cardiovascular Problems
The persistent high blood pressure associated with renal artery stenosis can lead to:
- Heart enlargement
- Heart failure
- Increased risk of heart attack
- Greater chance of stroke
Metabolic Imbalances
As kidney function declines, the body may develop imbalances in:
- Electrolytes (particularly potassium and sodium)
- Acid-base balance
- Waste products in the blood
