Subclavian artery stenosis is a vascular disorder that may affect blood flow to the arm and sometimes to the brain, leading to symptoms that vary in severity from person to person. In many cases, the stenosis develops gradually and goes unnoticed in the early stages, and then begins to cause functional issues as the condition progresses. Early diagnosis and appropriate subclavian artery stenosis treatment can minimize complications and improve the ability to perform daily activities and quality of life.
What is subclavian artery stenosis?
Subclavian artery stenosis is a condition in which one of the main arteries responsible for delivering oxygen-rich blood to the arm becomes narrowed and may also affect the perfusion of the neck or head. This narrowing is often caused by a buildup of plaque, a combination of fat and cholesterol, within the artery, resulting in reduced blood flow to the areas fed by the artery.
Subclavian artery stenosis is a form of peripheral arterial disease, similar to what occurs when the arteries in the legs are narrowed. In many cases there are no obvious symptoms because other arteries may compensate for the lack of perfusion, but some patients may experience symptoms in the arm or transient neurological symptoms. The stenosis occurs more often on the left side than on the right, and rarely affects both arteries. The condition is found in between 2% and 7% of the general population, with a higher incidence in those with peripheral vascular disease.
Causes of subclavian artery stenosis
Subclavian artery stenosis is caused by a variety of causes that narrow the lumen of the artery or affect its structure, most notably:
- Atherosclerosis is caused by the buildup of fat and cholesterol within the artery wall
- Inflammatory diseases of the blood vessels, such as arteritis, including Takayasu’s disease
- Exposure to chest radiation therapy
- External pressure on the artery, as in thoracic outlet syndrome
- Structural disorders of the artery wall, such as fibromuscular dysplasia or abnormal cell growth
- Direct injury to the artery from previous trauma or surgery
- Birth defects in which the subclavian artery is underdeveloped or partially absent
Risk factors
Factors that increase the risk of subclavian artery stenosis, often related to lifestyle or general health, include:
- Older age, especially after age 50, or a family history of arterial or heart disease or stroke
- Current or previous smoking
- High blood pressure, diabetes, andhigh cholesterol levels
- Overweight or obesity with physical inactivity and poor nutrition
- Lower extremity peripheral arterial disease, or a history of stroke or heart attack
Symptoms of subclavian artery stenosis
In many cases, stenosis of the subclavian artery does not cause obvious symptoms, especially when the stenosis is mild or develops slowly, as other blood vessels may compensate for the ischemia. Symptoms usually appear when the severity of the stenosis increases, often when the blockage exceeds about 50% of the artery’s diameter, and may vary depending on the area affected by the ischemia.
Arm symptoms
These symptoms are caused by a lack of blood flow to the upper limb, and usually increase with exertion or prolonged use of the arm, and include:
- Arm pain or muscle fatigue when used
- Muscle cramps or spasms in the affected arm
- Numbness or tingling in the arm or hand
Neurological symptoms
In some cases, the narrowing of the subclavian artery is close to its beginning, resulting in a lack of blood flow to the arm. The body then resorts to a compensatory mechanism, drawing blood from the neighboring vertebral artery instead of going to the brain to nourish the affected arm. This condition is known as subclavian steal syndrome.
As a result of the lack of blood supply to the brain, neurological symptoms may occur, including:
- Dizziness or lightheadedness, which may be accompanied by a feeling of near unconsciousness or fainting
- Problems with vision or balance
- Less common symptoms, such as confusion or temporary hearing loss
How is subclavian artery stenosis diagnosed?
The diagnosis of subclavian artery stenosis is based on clinical assessment, followed by the use of imaging tests to confirm the diagnosis and determine the location and severity of the stenosis and its effect on blood flow. The doctor begins by examining the patient and comparing the perfusion between the upper extremities, then chooses the most appropriate imaging modality based on the severity of symptoms and clinical suspicion. Diagnostic methods include the following:
- Clinical examination and measurement of blood pressure in the arms: The pulse is checked in the arms and wrists, and the blood pressure in both arms is measured and compared. A difference of more than 10-15 mmHg may indicate a narrowing of the subclavian artery, and the affected hand may feel cold or hear an abnormal sound when the artery is examined with a stethoscope.
- Ultrasound imaging: A non-invasive test used to assess blood flow within the subclavian artery that helps detect the presence and severity of stenosis by studying the speed and direction of blood flow.
- CT angiogram: Used to obtain detailed images of the arteries using CT scans with a contrast material, which helps to pinpoint the exact location and severity of the stenosis.
- Magnetic Resonance Angiography (MRA): An imaging test that shows the arteries and blood flow using magnetic resonance and is an option in some cases to evaluate the arteries without the use of X-rays.
- Traditional angiogram: An invasive test in which a thin catheter is inserted into an artery and a contrast agent is injected to directly visualize the subclavian artery. In some cases, digital subtraction technology is used, which helps to show blood vessels more clearly by reducing the appearance of non-vascular structures such as bones in the image.
When does subclavian artery stenosis need treatment?
Not all patients with subclavian artery stenosis require interventional treatment, as medical monitoring and follow-up may be sufficient in mild cases that do not cause a significant clinical impact. In these cases, the management focuses on controlling risk factors and regular follow-up to assess the progression of the condition.
Treatment becomes necessary if the condition progresses clinically, if there is evidence that the stenosis is affecting the upper extremity or brain perfusion, or if the stenosis is severe and functionally compromised. It is also considered when conservative management fails to stabilize or when the stenosis worsens over time. The final treatment decision depends on the severity of the stenosis, its functional consequences, and the patient’s overall health status, and is made after a thorough evaluation by the medical team.
Subclavian artery stenosis treatment methods
Treatment of subclavian artery stenosis depends on the severity of the stenosis, the presence of symptoms, and the impact of the condition on blood perfusion. Treatment options range from conservative treatment in mild cases to vascular intervention or surgery in more advanced cases.
Drug therapy and follow-up
Conservative treatment is used in patients with mild or asymptomatic stenosis, aimed at limiting disease progression and minimizing the risk of complications, and includes:
- Medications: Medications to prevent clots from forming and improve blood flow, as well as medications to control blood pressure, lower cholesterol, and control blood sugar levels when needed.
- Risk factor modification: Stop smoking and control vascular risk factors that contribute to the development of stenosis.
- Diet and physical activity: Eat a diet low in saturated fat, cholesterol, and sodium, and engage in appropriate physical activity as directed by your doctor.
This approach is a preventative treatment and does not remove the stenosis itself, but it may be sufficient in some cases.
Catheter therapy (vascular interventions)
Catheterization is a common interventional option to open a narrowed artery and improve blood perfusion. This procedure is characterized by:
- Less invasive than open surgery
- Usually performed under local anesthesia
- The patient is allowed to go home the same day in most cases
Surgical treatment
Surgical treatment is used in specific cases, such as a complete blockage of the artery, or when catheterization therapy is inappropriate or has failed. In these cases, the surgical intervention is a bypass procedure, where blood is diverted around the blocked part of the artery using another blood vessel to improve the blood supply to the upper limb.
This option is more invasive compared to vascular intervention, requires general anesthesia and full medical preparation, and is usually used in cases that cannot be treated with less invasive methods.
Catheterization for subclavian artery stenosis
Catheterization is a common interventional option to treat subclavian artery stenosis, especially when the stenosis is affecting blood perfusion. This procedure aims to reopen the artery and improve blood flow in a minimally invasive manner compared to open surgery.
The steps of the procedure are as follows:
- Giving local anesthesia in the catheter insertion area
- Inserting a thin catheter through an artery in the arm or wrist under radiation guidance
- Guide the catheter to the site of the stenosis within the subclavian artery
- Inflating a small balloon inside the narrowed area to widen the artery and push plaque to the wall
- Placing a stent inside the artery when needed to help keep it open and reduce the likelihood of restenosis
The procedure usually takes one to two hours, depending on the case, and in most cases, the patient can leave the hospital the same day after a short observation period, with a shorter recovery period compared to open surgery.
Treatment and follow-up results after catheterization
Studies show that initial success rates for catheterized subclavian artery dilation are high when patients are appropriately selected, with a clear improvement in symptoms within a short period after the procedure. In most cases, improved perfusion is sustained over the medium and long term with adherence to treatment and follow-up.
After catheterization, the patient undergoes periodic medical follow-up to ensure that the artery remains open and does not re-narrow. Follow-up usually includes a clinical examination and measurement of blood pressure in the arms, and an ultrasound may be required to monitor the blood flow within the artery.
Patients are advised to adhere to prescribed drug therapy, which may include antiplatelet medications and medications to control blood pressure and cholesterol, as well as continuing to modify risk factors such as smoking cessation and diabetes management. These measures help reduce the likelihood of restenosis and improve long-term outcomes. Recovery time varies from person to person, but most patients can return to their daily activities within a short period of time, following their doctor’s instructions and regular follow-up.
Finally, subclavian artery stenosis is a vascular disorder that may progressively develop and affect the blood supply to the upper limb or brain when neglected, so early diagnosis and regular follow-up help to minimize the risk and make the right treatment decision at the right time. Catheterization is an effective and minimally invasive treatment option in most appropriate cases, while surgery remains a solution for more complex cases, and achieving the best results depends on choosing the most appropriate treatment method for each patient while continuing to control risk factors and adhering to long-term medical follow-up.
Sources:
- American College of Cardiology. (2018). Subclavian artery disease. CardioSmart.
- Caesar-Peterson, S. & Bishop, M. A. (2025). Subclavian artery stenosis. In StatPearls . Treasure Island (FL): StatPearls Publishing.