Continued progression of thoracic outlet syndrome may develop into thromboembolism, muscle atrophy, and nerve damage. 1. Thromboembolism: If thoracic outlet syndrome is not treated in time, it causes thromboembolism, which leads to dislodgement of blood clots and seriously affects the surrounding blood vessels. 2. Muscle atrophy: Thoracic outlet syndrome causes muscle atrophy, which will lead to muscle weakness and a gradual reduction in muscle size, affecting the overall appearance. 3. Nerve damage: Patients with thoracic outlet syndrome may experience severe nerve damage, which can easily affect nerve function. If the diagnosis of thoracic outlet syndrome is confirmed, timely and targeted treatment, some patients have a good prognosis and can resume normal activities. For patients with complications, they need to go to the hospital regularly for review, and then combined with the guidance of specialized physicians for targeted treatment.