Cause:Atherosclerosis of subclavian artery
Pathophys:Steal syndrome due to retrograde vertebral arterial flow to arm which, with exercise, siphons ("steals") blood from cerebral circulation
Sx:Precipitated by arm exercise (20%), head turning to side, standing. Dizziness (11/13); transient blurred vision (6/13); syncope (4/13); aphasia (4/13); dysarthria (3/13); dementia (6/13)
Si:Diminished capillary filling with arm elevation; diminished pulse in arm (13/15); left arm to right arm BP differences of >20 mm Hg (11/13); bruit in 8/9 incomplete blocks, 1/6 complete blocks; lateralizing motor or sensory changes (4/13)
Lab: Noninv:Doppler analysis as good as angiography; 30-msec delay in pulse measurable
Xray:Angiography; MRA or duplex scanning of neck to detect retrograde vertebral flow
Rx:Surgical reconstruction; carotid vertebral bypass when on left; vertebral artery ligation especially when on left; on right can precipitate a carotid steal; a minor procedure. Contraindications: vertebral thrombosis, high technical risk, hemodynamically insignificant risk; morbidity/mortality: 1/13 postop mortality; 2/13 have residuum from preop stroke; cmplc: contralateral steal syndrome, especially if repair a total occlusion and a partial exists on other side (Nejm 1967;277:64)