Digital ischemia: angiographic differentiation of embolism from primary arterial disease.

Embolic disease is often overlooked as a cause of digital ischemia. Unilateral symptoms, in particular, should suggest the possibility of emboli arising from the subclavian or more distal upper extremity vessels. Emboli may originate in the subclavian artery as the result of atherosclerosis at its origin or arterial injury secondary to thoracic outlet compression. Arteriography can be useful in the identification of upper extremity emboli and their source, and should include studies of the aortic arch, proximal subclavian artery, and digital arteries. Retrograde subclavian injections may be required to adequately demonstrate the origin of the subclavian artery. Magnification technique is often essential in differentiating small digital artery emboli from primary arterial diseases, such as Buerger disease or scleroderma.