Renal Artery Stenosis: Causes, Treatments, and Outcomes

Q: Renal Artery Stenosis: Causes, Treatments, and Outcomes

Hello： Based on your description, the diagnosis should be left-sided "renal artery stenosis," which refers to the narrowing or blockage of the artery supplying blood to the kidney. <br>If the condition is significant, it typically leads to elevated blood pressure and, over time,

Renal artery stenosis

Hello Dr.
Chen,
I have been experiencing frequent urination and my blood pressure is 130/90.
After going to the hospital for an ultrasound, it was found that my kidneys are of different sizes (left kidney 9 cm, right kidney 12 cm).
I have been under follow-up for about six years and have been taking antihypertensive medication, with my blood pressure reaching a maximum of 139/93 and the best being 120/80.
Recently, I have been experiencing nocturia twice with increased urine volume and episodes of dizziness, leading to a slight rise in blood pressure to 140/95.

I changed hospitals for further examination, and the new physician used nuclear imaging and MRI to investigate the issue of the kidney size discrepancy.
They found that there is a problem with blood flow to the left kidney, with significant narrowing of the main blood vessel.
The medical advice is to first attempt catheter dilation; if that is unsuccessful, surgery will be necessary to create a bypass.
I would like to gather more opinions on this matter.
Is the smaller left kidney possibly a congenital anomaly or could it be due to acquired atrophy? If it is congenital, will these two procedures be effective? If it is acquired, what would be the outcome? The physician mentioned that medication is ineffective due to the vascular blockage, so would surgery restore kidney function? Thank you.

Nanping, 40~49 year old female. Ask Date: 2006/12/10

Dr. Chen Junji reply Urology

Hello: Based on your description, the diagnosis should be left-sided "renal artery stenosis," which refers to the narrowing or blockage of the artery supplying blood to the kidney.
If the condition is significant, it typically leads to elevated blood pressure and, over time, can cause kidney function impairment and renal atrophy.
There are many causes; in children or young adults, it is often due to congenital defects or fibromuscular dysplasia.
However, as one ages, it is usually caused by hypertension, diabetes, or hyperlipidemia leading to atherosclerosis (similar to vascular diseases in other areas such as the brain and heart) or arterial injury, among other factors.
Regarding treatment, the current first-line approach is "percutaneous renal artery balloon angioplasty ± stenting" (performed via the femoral artery in the groin or the radial artery in the wrist), which is similar to cardiac catheterization techniques.
Surgical intervention is considered a second-line treatment option.
If the treatment is successful, it can significantly improve hypertension, potentially eliminating the need for medication, and can enhance kidney function, preventing renal failure.

Reply Date: 2006/12/10

More Info

Renal artery stenosis (RAS) is a condition characterized by the narrowing of the renal arteries, which can lead to reduced blood flow to the kidneys. This condition can result in hypertension (high blood pressure) and can potentially cause kidney damage if not addressed. Understanding the causes, treatments, and outcomes of renal artery stenosis is crucial for managing this condition effectively.

Causes of Renal Artery Stenosis
1. Atherosclerosis: This is the most common cause of renal artery stenosis, especially in older adults. It involves the buildup of fatty deposits (plaques) in the arteries, leading to narrowing and reduced blood flow.

2. Fibromuscular Dysplasia (FMD): This is a less common cause, often seen in younger women. It involves abnormal growth of cells in the arterial wall, leading to a characteristic "string of beads" appearance on imaging studies.

3. Other Causes: Less frequently, renal artery stenosis can be caused by conditions such as vasculitis, radiation therapy, or external compression from tumors or other structures.

Symptoms
Patients with renal artery stenosis may experience symptoms such as:
- Resistant hypertension (high blood pressure that does not respond to standard treatment)
- Fluctuations in kidney function
- Symptoms of chronic kidney disease, such as fatigue, swelling, or changes in urination patterns.

In your case, the presence of a larger and smaller kidney, along with symptoms like increased urination and dizziness, suggests that there may be underlying issues related to blood flow and kidney function.

Diagnosis
Diagnosis typically involves imaging studies such as:
- Ultrasound: To assess kidney size and blood flow.

- CT Angiography or MR Angiography: To visualize the renal arteries and identify areas of stenosis.

- Nuclear Scintigraphy: To evaluate kidney function and blood flow.

Treatment Options
1. Medications: Initial management often includes antihypertensive medications to control blood pressure. However, as you noted, if the blood vessels are significantly narrowed, these medications may have limited effectiveness.

2. Angioplasty and Stenting: If imaging studies confirm significant stenosis, a common intervention is percutaneous transluminal renal angioplasty (PTRA), where a balloon is used to widen the narrowed artery. In some cases, a stent may be placed to keep the artery open.

3. Surgical Options: If angioplasty is unsuccessful or not feasible, surgical options such as renal artery bypass grafting may be considered. This involves creating a new pathway for blood flow to the kidney.

Outcomes
The effectiveness of treatment can vary based on the underlying cause of the stenosis. If the stenosis is due to atherosclerosis, lifestyle modifications (such as diet and exercise) and medical management can significantly improve outcomes. In cases of fibromuscular dysplasia, angioplasty often has a high success rate.

Regarding your specific concerns about the size of the left kidney, if it is indeed smaller due to congenital factors or atrophy from reduced blood flow, surgical intervention may help improve blood flow and potentially preserve kidney function. However, the extent of recovery will depend on the duration and severity of the stenosis prior to treatment.

Conclusion
In summary, renal artery stenosis is a significant condition that can lead to hypertension and kidney damage. Early diagnosis and appropriate management are crucial. It is essential to discuss your specific case with your healthcare provider, who can tailor a treatment plan based on your individual circumstances, including the potential for surgical intervention and the expected outcomes. Regular follow-up and monitoring of kidney function and blood pressure will be vital in managing your condition effectively.

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