Subclavian Artery Stenosis: Symptoms, Types, Causes and Treatment

Subclavian artery stenosis is a lesser-known but potentially serious vascular condition. It involves the narrowing (stenosis) of the subclavian arteries, which supply blood to the arms, brain, and, indirectly, the heart. This article brings together current evidence and clinical insights to help you understand its symptoms, types, underlying causes, and the latest treatment strategies.

Symptoms of Subclavian Artery Stenosis

Recognizing the symptoms of subclavian artery stenosis is crucial for timely diagnosis and effective management. Symptoms often go unnoticed, especially in the early stages, but can become disabling or even life-threatening as the disease progresses.

Symptom	Description	Affected Area	Source(s)
Arm Claudication	Fatigue, pain, or cramping with arm use	Upper extremity	1 2 4 5
Paresthesia	Tingling or numbness in the arm	Upper extremity	5
Vertigo/Dizziness	Lightheadedness or spinning sensation	Brain (vertebrobasilar)	1 3 5
Visual Disturbance	Blurred/temporary vision loss	Brain (ocular)	3
Syncope	Fainting episodes	Brain	3
Myocardial Ischemia	Chest pain, especially post-CABG	Heart	1 2 4
Rest Pain	Persistent pain in the arm at rest	Upper extremity	5 15

Table 1: Key Symptoms

Arm and Hand Symptoms

Many patients first notice symptoms in the arm or hand. These include arm claudication—pain or fatigue in the arm during activity, which improves with rest. Some experience tingling or numbness (paresthesia), muscle fatigue, or even pain at rest, especially if the blood supply is severely compromised 1 2 4 5.

Neurological Symptoms

Because the subclavian arteries supply blood to the vertebral arteries (which feed the brainstem and cerebellum), stenosis can lead to neurological manifestations. These may include:

• Vertigo or dizziness
• Imbalance
• Visual disturbances (blurring or temporary vision loss)
• Syncope (fainting)

These arise from vertebrobasilar insufficiency (VBI), a phenomenon sometimes labeled “subclavian steal syndrome” when blood flow reverses in the vertebral artery to compensate for the blocked subclavian 1 3 5.

Cardiac and Other Symptoms

In patients who have had coronary artery bypass grafting (CABG) using the internal mammary artery (IMA), subclavian stenosis may cause angina (chest pain) during upper limb exertion on the same side, a situation called “coronary-subclavian steal” 1 2 4. Rarely, severe stenosis may also lead to tissue loss or gangrene in the arm if blood supply becomes critically low 15.

Asymptomatic Cases

It’s important to note that many cases of subclavian artery stenosis are asymptomatic, discovered incidentally on imaging or during evaluation for other cardiovascular conditions 1 4 8. However, even in the absence of symptoms, the diagnosis is significant, as it often signals widespread vascular disease.

Types of Subclavian Artery Stenosis

Subclavian artery stenosis is not a one-size-fits-all diagnosis. Understanding the different types can help tailor diagnosis and treatment strategies for each patient.

Type	Defining Feature	Usual Cause	Source(s)
Proximal (Pre-vertebral)	Before vertebral artery branch	Atherosclerosis	1 6 9
Distal (Post-vertebral)	After vertebral artery branch	Rare; varied	1 9
Subclavian Steal Syndrome	Flow reversal in vertebral artery	Severe proximal stenosis	1 3 6 7
Left vs. Right Side	More common on left	Anatomy-related	7 9
Occlusive	Complete blockage	Advanced disease	5 10 15
Functional (Non-atherosclerotic)	Mechanical, e.g., thoracic outlet	Anatomic anomaly	11

Table 2: Types of Subclavian Artery Stenosis

Proximal vs. Distal Stenosis

• Proximal stenosis refers to narrowing before the vertebral artery branches from the subclavian. This is by far the most common site, especially for atherosclerotic disease, and is the classic cause of subclavian steal syndrome 1 6 9.
• Distal stenosis (after the vertebral artery) is much less common and may have different clinical implications 1 9.

Subclavian Steal Syndrome

A special type of stenosis occurs when the narrowing is so severe that it causes blood to flow backward (“steal”) through the vertebral artery to supply the arm, depriving the brain of adequate blood flow. This is known as subclavian steal syndrome. It can be classified as:

• Classical (atherosclerotic): Most cases are due to severe atherosclerotic narrowing 1 6 7.
• Non-atherosclerotic: Rarely, steal may occur without stenosis, such as in patients with large arteriovenous fistulas for dialysis 6.

Left vs. Right Subclavian Stenosis

• Left-sided stenosis is about four times more common than right-sided, largely because the left subclavian arises directly from the aorta, making it more exposed to atherosclerotic processes 7 9.
• Right-sided stenosis is less common and may be harder to treat endovascularly due to complex anatomy 7.

Occlusive vs. Functional Stenosis

• Occlusive disease can be either partial (stenosis) or complete (occlusion), with the latter causing more severe symptoms and requiring more complex intervention 5 10 15.
• Functional/mechanical stenosis can occur without atherosclerosis, such as in thoracic outlet syndrome where the artery is compressed by a bony anomaly like a prominent first rib 11.

Causes of Subclavian Artery Stenosis

Understanding the root causes of subclavian artery stenosis is key to both prevention and effective management. While atherosclerosis dominates, several other etiologies are recognized.

Cause	Description	Typical Population	Source(s)
Atherosclerosis	Plaque buildup narrowing the artery	Older adults, CV risk factors	1 4 5 8 9
Arteritis	Vessel inflammation (e.g., Takayasu)	Younger women, autoimmune	10
Mechanical Compression	Thoracic outlet syndrome, bony anomalies	Younger adults, anatomical variant	11
Iatrogenic	Post-surgical complications, graft issues	CABG, vascular surgery pts	1 2 6
Embolic	Clot or debris causing blockage	Variable	15
Congenital	Rare, malformations of aorta/vessels	Very rare	6

Table 3: Causes of Subclavian Artery Stenosis

Atherosclerosis

By far the most common cause, atherosclerosis involves the progressive buildup of fatty plaques inside the artery wall, leading to narrowing and reduced blood flow. It shares risk factors with other forms of peripheral artery disease (PAD), including:

• Hypertension
• Smoking
• High cholesterol
• Diabetes
• Established coronary artery disease

Most patients with subclavian stenosis also have atherosclerosis elsewhere, underscoring its importance as a marker of systemic vascular disease 1 4 5 8 9.

Arteritis

Inflammatory diseases such as Takayasu arteritis can lead to significant narrowing or even occlusion of the subclavian arteries, especially in younger women. The process involves immune-mediated inflammation and scarring of the vessel wall 10.

Mechanical Compression

Mechanical causes, such as thoracic outlet syndrome, result from external compression of the artery by anatomical structures—most commonly a cervical rib or an abnormally shaped first rib. This is rare but should be considered in younger patients with unexplained symptoms 11.

Iatrogenic and Other Causes

• Iatrogenic: Surgical procedures, especially coronary bypass grafting using the internal mammary artery, can lead to complications or reveal previously unrecognized subclavian stenosis (coronary-subclavian steal) 1 2 6.
• Embolic and Congenital: Very rarely, emboli or congenital vascular malformations may be responsible 6 15.

Treatment of Subclavian Artery Stenosis

Subclavian artery stenosis is a treatable condition, and management depends on the severity of symptoms, extent of disease, and underlying cause. Today, most patients benefit from minimally invasive treatments, but surgical options remain for complex cases.

Treatment	Description	Indication	Source(s)
Medical Therapy	Risk factor control, antiplatelets, statins	Asymptomatic/mild symptoms	8 12
Endovascular (PTA/Stenting)	Balloon angioplasty, stent placement	Symptomatic/severe stenosis	3 5 7 14 15 16
Surgical Bypass	Bypass grafting or transposition	Failed endovascular, occlusion	15
Surgical Decompression	Rib resection for thoracic outlet	Mechanical compression	11
Novel Techniques	Bioresorbable scaffolds, “kissing stents”	Selected complex cases	16 7

Table 4: Treatment Approaches

Medical Therapy

• Lifestyle modification and medical management are the cornerstones for asymptomatic or minimally symptomatic patients. This includes:
  • Smoking cessation
  • Blood pressure and cholesterol control
  • Antiplatelet agents
  • Statins
• This approach is also essential for all patients to reduce cardiovascular risk 8 12.

Endovascular Therapy

• Percutaneous Transluminal Angioplasty (PTA) and stenting are now the first-line treatments for most symptomatic patients. These minimally invasive procedures have high success rates, rapid recovery times, and low complication rates 3 5 7 14 15.
  • Stenting is often preferred, especially for ostial or heavily calcified lesions, and can be performed via femoral or brachial artery access 7 14.
  • Patency rates remain high at 1 and 5 years, though some patients may require reintervention for restenosis 3 14.
  • Bioresorbable vascular scaffolds and “kissing stents” are novel techniques for select cases 16 7.
• Follow-up includes regular clinical and imaging surveillance for recurrence.

Surgical Therapy

• Bypass surgery is reserved for patients with failed endovascular therapy, long segment occlusions, or specific anatomical challenges 15.
  • Options include carotid-subclavian, carotid-axillary, or subclavian transposition procedures 15.
• Surgical decompression (e.g., first rib resection) is indicated in cases of thoracic outlet syndrome due to anatomical compression 11.

Choosing the Right Approach

• Asymptomatic patients: Usually managed with medical therapy and risk factor modification.
• Symptomatic patients: Endovascular therapy is preferred for most; surgery is considered for failures or complex disease 12 14 15.
• Special circumstances: Surgery or novel endovascular devices may be used in unique anatomical or recurrent cases 7 16.

Conclusion

Subclavian artery stenosis is an important but often under-recognized vascular disease. Early identification and tailored treatment can prevent serious complications affecting the arms, brain, and heart. Here’s a summary of the key takeaways:

• Symptoms range from arm fatigue and paresthesia to dizziness, vision changes, and angina, but many patients are asymptomatic.
• Types include proximal/distal stenosis, subclavian steal syndrome, left- or right-sided disease, and can be occlusive or due to mechanical compression.
• Causes are most often atherosclerosis, but can also include arteritis, anatomical anomalies, and rare iatrogenic or congenital factors.
• Treatment is individualized: medical therapy for milder cases, endovascular angioplasty and stenting for most symptomatic patients, and surgery for those with advanced or complex disease.

By recognizing subclavian artery stenosis and understanding its management, patients and clinicians can work together to reduce vascular risk and improve quality of life.