The subclavian arteries are major pathways delivering oxygenated blood from the heart to the upper body. Located deep within the chest and neck, directly beneath the collarbones, these large vessels are normally well-protected by the bony structure of the upper thorax. Despite this protected position, damage to the subclavian artery poses an extremely serious threat due to the high volume and pressure of blood flowing through it. Injury often results in life-threatening complications.
The Subclavian Artery’s Location and Function
The subclavian arteries are paired vessels, one on the left and one on the right side of the body. The left subclavian artery arises directly from the aortic arch, while the right subclavian artery originates from the brachiocephalic trunk. Both arteries follow a path over the first rib, passing between the anterior and middle scalene muscles, before transitioning into the axillary artery in the armpit area.
This location allows the artery to supply blood to the entire upper extremity, including the shoulder, arm, and hand. The subclavian artery also gives off several major branches, including the vertebral artery (supplying the brain and spinal cord), the internal thoracic artery (supplying the chest wall), and the thyrocervical trunk (supplying the neck and shoulder). Any disruption of flow can therefore affect the limb, the central nervous system, and the chest.
Mechanisms of Injury
Because the subclavian artery is shielded by the clavicle and first rib, a significant amount of force or a direct, precise wound is usually required to cause damage. The most common cause of injury is severe trauma, which can be categorized as either penetrating or blunt. Penetrating trauma, such as stab wounds or gunshot injuries to the neck, shoulder, or upper chest, often results in direct laceration or puncture of the vessel.
Blunt trauma typically involves high-energy incidents like motor vehicle collisions or falls from a significant height. In these cases, the artery may be crushed or torn, particularly when associated with a fracture of the clavicle or first rib, as sharp bone fragments can sever the vessel. Blunt force can also cause the artery wall to stretch and tear, leading to a dissection or a blood clot that blocks flow.
Iatrogenic injury is a less common cause, occurring during medical procedures. This type of damage can happen during the attempted placement of a central venous catheter into the subclavian vein, which lies close to the artery. Non-traumatic mechanisms, such as a spontaneous aneurysm or chronic compression from thoracic outlet syndrome, can also damage the artery wall over time.
Immediate Consequences of Damage
Damage to the subclavian artery immediately leads to two potentially devastating consequences: massive hemorrhage and acute limb ischemia. Hemorrhage is the most immediate threat, as the subclavian artery is a large, high-pressure vessel directly connected to the aorta. A tear or complete transection can cause rapid, significant blood loss into the chest cavity or surrounding tissues, leading quickly to hypovolemic shock.
This severe internal bleeding often results in a massive hematoma, a collection of blood that can compress the trachea or surrounding structures. Without immediate control of the bleeding, the patient’s blood pressure will drop rapidly. Death can occur within minutes due to the speed and severity of the blood loss.
The second major consequence is ischemia, the lack of oxygenated blood flow to the arm and hand. If the artery is severely damaged or blocked by a clot, the upper extremity is immediately starved of blood. This condition is often described by the six P’s:
- Pain
- Pallor (paleness)
- Pulselessness
- Paresthesia (numbness or tingling)
- Paralysis
- Poikilothermia (coolness)
The presence of collateral circulation can sometimes mask the symptoms, but the limb remains at high risk. Prolonged ischemia can quickly lead to irreversible tissue damage. If blood flow is not restored within a few hours, the affected arm may require amputation to prevent widespread infection.
A third, common consequence of subclavian artery trauma is associated nerve injury. The brachial plexus, a complex network of nerves controlling movement and sensation in the upper extremity, is situated immediately adjacent to the artery. The same blunt or penetrating force that damages the artery often injures these nerves, resulting in immediate neurological deficits.
Diagnosis and Treatment Options
A medical professional may suspect subclavian artery damage based on the mechanism of injury, such as trauma to the upper chest or neck, and signs like a weak or absent pulse in one arm compared to the other. Hard signs of vascular injury, including active bleeding or an expanding hematoma in the supraclavicular area, prompt immediate intervention. However, many patients present with only subtle or soft signs, complicating the initial diagnosis.
Diagnostic imaging is typically performed on stable patients to confirm the injury and plan treatment. Computed Tomography Angiography (CTA) is the preferred method, as it quickly provides detailed images of the blood vessels and surrounding structures, including bone fractures. In certain cases, a traditional angiography, which involves inserting a catheter and injecting dye, may still be used, sometimes simultaneously with treatment.
Treatment for a damaged subclavian artery focuses first on immediate stabilization and controlling the hemorrhage. For hemodynamically unstable patients, immediate open surgical exploration is often necessary to gain control of the bleeding vessel. Open repair involves accessing the artery through large incisions, such as a median sternotomy or supraclavicular approach, and then repairing the damage, often by suturing the vessel or placing a synthetic graft to bypass the injured segment.
An increasingly common alternative for stable patients is endovascular repair. This method involves accessing the artery through a small puncture in the groin or arm and then guiding a covered stent-graft to the injured segment using X-ray guidance. The stent-graft acts as a new lining inside the artery, sealing the tear and restoring normal blood flow. This approach typically results in less blood loss and a shorter hospital stay.