Introduction Acute upper extremity ischemia caused by a proximal occlusion at the level of the subclavian artery Epidemiology Incidence rare <1% of population Risk factors aortic arch abnormality aortic arch syndrome trauma arterial catheterization pre-existing stenosis Etiology Pathophysiology pathophysiology limb pain occurs secondary to lack of blood flow to the extremity pathoanatomy unclear but may be secondary to nonocclusive proximal atherosclerotic plaque and/or cardiac embolization Anatomy Blood Supply left subclavian is the third branch off the aortic arch right subclavian is one of two branches of the brachiocephalic (innominate) artery Biomechanics subclavian supplies vertebral artery which join to form basilar artery to supply cerebellum Presentation History sudden onset of symptoms without inciting event Atrial fibrillation is associated in 80% of the cases of upper extremity thromboembolism Symptoms common symptoms arm pain nausea severity paresthesias Physical exam inspection cyanotic/pale upper extremity diffuse tenderness cold limb neurologic a normal neurologic examination is common neurovascular pulses absent (axillary, brachial, radial, and ulnar) doppler signals may be present in nonocclusive disease provocative different blood pressures may be noted on affected and unaffected upper extremity increased pain and fatigue with upper extremity with the exertion of the limb Imaging Arteriography recommended diagnostic modality allows for percutaneous treatment of the occlusion CT angiography can be performed expeditiously to rule out other causes of occlusion MRA cannot treat occlusion at time of diagnosis Doppler ultrasonography Echocardiography can rule out cardiac embolus following treatment of thrombosis Studies Labs hypercoagulable panel be performed to rule out underlying disorder labs often unremarkable Treatment Nonoperative oral and IV anticoagulation indications limited role for nonoperative treatment with limb-threatening ischemia intravenous and oral anticoagulation can be used to supplement percutaneous or surgical treatment Operative percutaneous treatment indications any patient with symptomatic limb ischemia techniques intra-arterial thrombolysis percutaneous transluminal angioplasty (PTA) manual aspiration stenting surgical treatment indications any patient with symptomatic limb ischemia techniques embolectomy/thrombectomy bypass grafting Complications Limb ischemia gangrene loss of limb Basilar stroke delay in diagnosis prolonged ischemia can progress to decreased cerebral perfusion and acute stroke symptoms iatrogenic if vertebro-basilar artery system is left unprotected during endovascular treatment embolism can occur Prognosis Outcomes with treatment favorable prognosis has been reported with prompt recognition and treatment Outcomes without treatment progression to stroke and upper extremity amputation