Subclavian Artery Thrombosis - Symptoms, Diagnosis, and Treatment

Introduction

In the thoracic region, there is a pair of huge arteries that arise from the arch of the left aorta and the right brachiocephalic trunk, also known as the subclavian arteries that continue to be the axillary artery. This artery divides into several branches, which include the vertebral arteries that supply approximately 20 percent of the oxygenated blood to the brain. The subclavian artery, just like other vital arteries, is prone to developing thrombosis (clotting of blood in the arteries or veins). Thrombosis of the subclavian artery generally goes underdiagnosed or misdiagnosed. Subclavian artery thrombosis occurs in the left subclavian artery four times more than in the right subclavian artery. This condition may lead to significant damage to the upper limbs, brain, and heart. Atherosclerosis is established to be one of the main causative agents of subclavian artery thrombosis. Congenital deformities additionally play a significant role in the development of subclavian artery thrombosis. This condition is more common in patients who are suffering from peripheral vascular disease, coronary artery disease, lower extreme artery disorder, and carotid artery disease.

What Are the Changes That Occur in the Body During Subclavian Artery Thrombosis?

The significant risk factors for the development of subclavian artery thrombosis remain the same as thrombosis formation in any other part of the body. The most potential factors are obesity, long-standing hypertension, diabetes mellitus, a habit of smoking, and metabolic syndrome. Parallel to any other artery thromboses, the subclavian artery thrombosis also affects an area that has been subjected to an increased amount of shear stress that may lead to an endothelial injury and, thus, subsequent aggregation of platelets along with the release of platelet-derived growth factors. This pathophysiological sequence will trigger the abnormal proliferation of all the smooth muscle cells that are present in the inner lining of the blood vessel and hence will begin forming the locus of an atherosclerotic plaque or deposit.

What Are the Causes of Subclavian Artery Thrombosis?

As mentioned before, atherosclerosis is the leading cause of subclavian artery thrombosis. It should not be misunderstood as arteriosclerosis. Atherosclerosis refers to a pattern of the well-known disease, arteriosclerosis. In this, the walls of any particular artery develop specific abnormalities known as a lesion. On the other hand, arteriosclerosis refers to the thickening of the arterial walls along with the loss of elasticity of the same. Mentioned below are a few of the causative factors behind the formation and development of subclavian artery thrombosis.

• Atherosclerosis.

• Inborn deformity.

• Fibromuscular dysplasia.

• Neurofibromatosis.

• Autoimmune vasculitis.

• Decreased blood flow in the basilar artery.

• Takayasu radiation exposure.

• Neurofibromatosis.

• Trauma or injury.

• Embolic debris.

• Retrograde flow of blood in the vertebral artery.

• Compression disorders.

• Internal mammary artery graft.

What Are the Signs and Symptoms of Subclavian Artery Thrombosis?

Any kind of thrombosis occurs when the blood vessel, either artery or vein, develops a clot. The factors that lead to the formation of a clot in subclavian artery thrombosis include the rate of blood flow, the thickness of the blood, and the quality of the walls of the blood vessel. Depending on these factors, the patient may present several clinical manifestations. Mentioned below are a few of the signs and symptoms of subclavian artery thrombosis:

• Arm claudication.

• Muscle fatigue.

• Pain in the body during rest.

• Finger necrosis.

• Vertebrobasilar hypoperfusion.

• Diplopia (double vision).

• Drop attacks.

• Syncope (fainting).

• Ataxia.

• Vertigo.

• Dysphasia (swallowing difficulty).

• Dysarthria.

• Dizziness.

• Nystagmus (rapid, repetitive, and uncontrolled eye movements).

• Tinnitus (ringing in the ears).

• Hearing loss.

• Facial sensory deficits.

• Angina pectoris.

• Stenosis.

• Coronary steal syndrome.

• Vertebrobasilar insufficiency.

• Unequal blood pressure in both arms.

• Absence of axillary pulse.

• Anxiety.

• Palpitations.

• Rapid breathing.

• Chest pain that lasts for five minutes.

• Chest pain while climbing stairs.

• Nausea.

• Shortness of breath.

• Vomiting.

• Excessive

• sweating.

• Dizziness.

• Ulceration of the fingers.

• Diminished radial and brachial pulse.

• Suoraclavicular bruits are dull.

• Ischemia.

• Gangrenous skin.

• Splinter hemorrhages.

How to Diagnose Subclavian Artery Thrombosis?

A physical examination along with the medical and family history is of key importance during the diagnosis of subclavian artery thrombosis because this condition is known to be misdiagnosed or underdiagnosed. During a physical examination, the healthcare provider must focus on the cerebral circulation of the patient, which involves palpation of the carotid arteries and auscultation of the vertebral and suboccipital region. In addition, a difference of less than 10 mm Hg (millimeter mercury) in the inter-arm systolic blood pressure may be a vital sign of subclavian artery thrombosis. Mentioned below are a few of the diagnostic tools that help in the diagnosis of subclavian artery thrombosis.

• Increase in systolic blood pressure to 20 mm Hg.

• Duplex ultrasound is a non-invasive imaging tool with color flow.

• Doppler ultrasonography.

• Tomography.

• Angiography.

• Magnetic resonance angiography.

• D-dimer test.

• Compression ultrasonography.

• Magnetic resonance imaging.

• Magnetic resonance venography.

• Complete blood picture.

How to Manage and Treat a Case of Subclavian Artery Thrombosis?

There are certain factors that qualify a patient to undergo treatment for subclavian artery thrombosis. Mentioned below are the criteria:

• 57 percent morbidity of the upper arm ischemia.

• Upper limb claudication is present.

• The upper extremity begins to pain at rest.

• Digits embolization.

• 37 percent vertebrobasilar insufficiency is seen due to steel syndrome.

• Leg claudication.

• Presence of axillofemoral graft.

In case the patient has all the above present, medical therapy with antiplatelet drugs is begun. Aspirin or Clopidogrel is the drug of choice at the beginning of the treatment. Other medications include HMG-CoA reductase inhibitors, angiotensin-converting enzymes or ACE inhibitors, and angiotensin receptor blockers. The subclavian artery may also be surgically corrected with the several invasive procedures that are present. Mentioned below are a few of them:

• Axillary-axillary bypass.

• Carotis-subclavian bypass.

• Transposition of the artery.

• Endovascular intervention.

• Stenting.

• Transluminal angioplasty.

Conclusion

Subclavian artery thrombosis refers to a blood clot that is formed in the subclavian artery. There are several causes for this condition, but atherosclerosis has been reported to be the chief etiological factor. Treatment includes both invasive and non-invasive management, with surgical correction proving to give a favorable prognosis. The patient is counseled to quit the habit of smoking and must begin living a heart-healthy lifestyle. In case the patient has diabetes, they are suggested to maintain strict glycemic control with the HbA1c target of less than seven.