Surgeons make treatment decisions based on assigning the patient to one of the following three clinical scenarios:
Explicitly, the presence or absence of acute arterial occlusion determines the urgency of the clinical situation. Firstly, the presence of arterial occlusion mandates urgent treatment aimed at removing the blood clot and restoring adequate blood flow. In contrast, the absence of arterial occlusion allows the surgeon time to stabilize the patient and perform definitive treatment electively. Secondly, patients may have arterial compression and arterial damage without arterial occlusion. Surgeons treat these patients less urgently with decompression and arterial repair. Thirdly, some patients have arterial compression but no arterial damage or occlusion. Surgeons usually treat these patients electively with decompression alone.
Learn more in the sections below.
Acute arterial embolism causing arterial occlusion
A blood clot can break off from the subclavian artery, travel to a distal artery, and occlude that artery. In this event, the clot, called an arterial embolus, partially or completely blocks blood flow to the arm or hand.
Doctors call this process acute arterial insufficiency.
Acute arterial insufficiency can cause partial or complete loss of function of the arm or hand. In severe cases, it can cause gangrene, or tissue death. For these reasons, surgeons treat patients urgently.
In almost all cases, the surgeon will start treatment immediately with anticoagulants, or blood thinners. Instead, some surgeons will perform a procedure called thromboembolectomy. Surgeons perform a thromboembolectomy by inserting a catheter into the affected artery and removing the embolus. When successful, this process restores arterial blood flow to the affected area. As long as there is successful restoration of blood flow, the surgeon can perform definitive treatment non-urgently.
Definitive treatment includes removal of the first rib and repair of the damaged arterial segment or aneurysm with a graft. The surgeon will also remove a cervical rib, if it is present.
Arterial compression causing symptoms without acute arterial insufficiency
In these patients, extrinsic structures or abnormal arm movement cause compression of the subclavian or axillary artery. As a result, structural damage of the artery occurs, which may result in a scar and stenosis, or an aneurysm. Consequently, extrinsic compression and structural damage eventually causes symptoms, including chronic arterial insufficiency or a pulsatile mass.
Chronic arterial insufficiency results in fatigue and arm pain, often called claudication (read more here).
Because these symptoms develop gradually, surgeons do not treat these patients as urgently as they do those with acute arterial insufficiency.
Arterial compression without symptoms
In these patients, extrinsic structures or abnormal arm movement cause compression of the subclavian or axillary artery. As a result, structural damage of the artery occurs, which may result in a scar and stenosis, or an aneurysm. However, the patients have no symptoms related to the arterial compression or arterial damage.
As long as the patient is asymptomatic, the surgeon does not need to begin treatment urgently. Instead, the surgeon can select elective treatment. When imaging proves arterial compression or damage, the surgeon electively performs decompression of the thoracic outlet without arterial repair. Following decompression, the patient undergoes long-term surveillance imaging with CT or MR angiography. In the event that surveillance imaging demonstrates new or progressive arterial stenosis or aneurysm, the surgeon will repair the artery.
Arterial TOS patients generally experience good treatment outcomes. However, treatment outcomes depend on several factors. In particular, the presence or absence of acute arterial insufficiency demands urgent treatment. When the surgeon promptly and successfully completes diagnosis and treatment in these patients, the patient avoids the potential severe complications.
In summary, assuming successful treatment or absence of acute arterial insufficiency, decompression and repair of the artery are usually successful. Most patients can return to normal function without ongoing or recurrent symptoms.
Active discussion remains among experts regarding surgical decisions based on aneurysm size or the degree of arterial compression.