Thoracic Outlet Syndrome Masquerading as Coronary Artery Disease (Pseudoangina)

Abstract

Forty-four patients presenting with chest pain suggesting coronary artery disease had normal exercise stress tests and selective coronary angiography and subsequently were found to have an unsuspected thoracic outlet syndrome. Thirteen additional patients had both significant coronary artery disease and thoracic outlet syndrome. Esophageal and pulmonary disease were ruled out and the diagnosis of brachial plexus compression in the thoracic outlet established by a reduction of the ulnar nerve conduction velocity (UNCV) below normal, the normal value being 72 meters per second. Clinical improvement from thoracic outlet compression resulted either from physical therapy if the UNCV's were above 55 m./sec, or from transaxillary surgical extirpation of the first rib if the UNCV's were below 55 m./sec. Thirteen patients with coronary artery disease and thoracic outlet syndrome required therapy for both problems before improvement ensued. Although the usual symptomatology for thoracic outlet syndrome involves pain and paresthesias of the shoulder, arm, and hand, the chest wall is frequently involved. If the chest pain is predominant with minimal shoulder-hand symptoms, the diagnosis is not suggested clinically and can only be established by the high index of suspicion, positive UNCV reduction, and a normal coronary angiogram. Pathways of pain in angina pectoris and afferent stimuli originating from brachial plexus compression at the thoracic outlet stimulate the same autonomic and somatic spinal centers that induce referred pain to the chest wall and arm.