Venous TOS is quite uncommon. However, patients with venous TOS have a very dramatic presentation, and complications can be serious. In these patients, blood clot forms in the main vein draining the arm. Although some treatment questions remain unsettled, doctors treat the blood clot urgently. Following this, doctors undertake diagnosis and treatment of the underlying cause.
Causes of Venous TOS
A single large subclavian vein drains most of the blood flow from the arm towards the heart. In some patients, external structures compress and damage this vein. While doctors do not yet fully understand the mechanism of damage, blood clot forms within the damaged vein. This blood clot prevents normal venous drainage of the arm. As a result, the patient may experience arm swelling and heaviness. In addition, the blood clot may break off and travel to other veins. In that case, severe complications can develop.
Symptoms of Venous TOS
Since the venous blood clot prevents drainage of blood, arm swelling will occur. Patients often note ‘heaviness’ of the arm. In addition, a blue or purple skin color may appear, due to loss of oxygen from the trapped blood. In the event the blood clot breaks off, patients may experience a pulmonary embolism. Pulmonary embolism occurs when blood clots block blood flow through the lungs. In that case, patients will have shortness of breath, often severe. Pulmonary may be life-threatening.
Diagnosis of Venous TOS
Doctors should make the presumptive diagnosis based on their clinical examination. When a doctor suspects venous TOS, she will order imaging tests to prove the presence of a venous blood clot. After treatment of the blood clot, imaging tests show the damaged vein segment and the external structures compressing the vein.
Treatment of Venous TOS
It is important to realize that the primary treatment goal is to stabilize or remove the venous blood clot. Following this, doctors repair the damaged vein at the site of blood clot. In most cases, doctors will remove the external structures that compressed and damaged the vein.