1. What is an Aneurysm?
An aneurysm is an abnormal dilation of a blood vessel. This involves all layers of the vessel wall. Aneurysms pose a risk to health due to their potential to rupture, thrombose or embolize. The most common blood vessels involved are the abdominal and thoracic aorta, and circle of Willis (brain). Aneurysms of the subclavian artery (under the clavicle) are uncommon, accounting for less than 1% of all peripheral aneurysms.
2. What are the causes of Aneurysm of the Subclavian Artery?
The most common causes are arteriosclerosis (hardening of the arteries), thoracic outlet obstruction (a mechanical, poststenotic dilation), post-traumatic (i.e. gun-shot, blunt trauma), aberrant (malposition) right subclavian artery and miscellaneous. Rare causes include: syphilis, tuberculosis and abnormalities of the vessel wall (fibromuscular dysplasia).
3. What are the typical symptoms?
In most cases an asymptomatic pulsatile mass is detected either above or below the clavicle (collar bone). Symptoms such as dysphagia (difficulty swallowing), stridor (difficulty breathing), chest pain, hoarseness, upper extremity fatigue, numbness/tingling and gangrene or ulceration of the fingers may develop with progressive enlargement of the aneurysm. These result from compression of adjacent structures (i.e. nerves, veins, trachea or esophagus), thromboembolism (blood clots breaking off from the wall of the aneurysm) or rupture into the soft tissues of the neck.
4. Are Subclavian Aneurysms dangerous?
Yes - thromboembolism (distal travel of atherosclerotic debris or vessel wall thrombus) can lead to limb-threatening complications. There also is a potential for TIA or stroke. Rupture of the subclavian artery may result in vomiting of blood due to bleeding into the lung tissue, severe pain, shock and death.
5. How can I find out if have an Aneurysm?
Clinical findings are frequently present such as finger gangrene, upper extremity paresthesias (nerve pain and numbness), musculoskeletal abnormalities (cervical rib) or blood pressure differences between the upper extremities.
Arteriography (injection of dye into the blood vessel with sequential X-ray pictures) is an accurate way to confirm the diagnosis. Other tests such as MRI, CT scans and Doppler may add useful information. However, they are not as accurate as an arteriogram and may only add to your expenses. A chest x-ray can be useful to find out about a first cervical rib (thoracic outlet syndrome) or other bony abnormality.
6. What is the treatment of choice?
Almost all aneurysms of the subclavian artery (if they are of significant size, e.g. greater than 2 cm) should be repaired. Surgery involves repair of the aneurysm with a vein (usually harvested from the lower extremity) or synthetic graft material. If a first cervical rib or other musculoskeletal abnormality is present then it should be removed during the procedure.
7. What are the risks of surgical repair?
The complication risk of surgery is related to experience and skill of the surgeon, hospital expertise and the basic underlying health of the patient. Complication and mortality rates are frequently reported to be as low as 0 to 2% in academic medical centers with peripheral vascular surgery specialists and superior intensive care. These rates may be higher in small community hospitals without dedicated vascular specialists. The 5 year and 10 year survival rates are over 90% and 60-70%, respectively.
8. How long does it take to recover, and what is the likelihood of returning to normal life?
As with any surgical procedure, recovery time varies depending on the underlying health of the individual and the magnitude of the operation. In general, a few weeks of recovery are to be expected as there may be a chest and/or a collar incision that need to heal.
The likelihood of returning to normal life is good. Most patients are able to resume all of their usual activities with no restrictions. Follow-up is minimal. However, a sound repair can be ensured by regularly scheduled ultrasound imaging of the conduit (vein or synthetic) used to repair the aneurysm.
Frequently Asked questions about Aneurysm of the Subclavian Artery, prepared by:
Luis F. Saca,
MD Kaiser Foundation Medical Center
Jeffrey L. Ballard, MD, FACS
Associate Professor of Surgery
Division of Vascular Surgery
Loma Linda University Medical Center
Loma Linda, CA