CORONARY-SUBCLAVIAN STEAL SYNDROME - REPORT OF 5 CASES

The internal mammary artery (IMA) is the conduit of choice for cardiac revascularization. The phenomenon of retrograde flow in this graft se condary to proximal subclavian artery stenosis is an infrequent but in creasingly recognized clinical entity and has been termed the ''corona ry-subclavian steal syndrome.'' We report on five patients with this s yndrome. All were men. The average age was 65 years (range 56 to 68 ye ars). The mean interval from coronary bypass to presentation was 7.8 y ears (range 1 month to 18 years). Three patients presented with unstab le angina and one with congestive heart failure. One patient was asymp tomatic from a cardiac standpoint. The mean arm systolic blood pressur e differential was 45 mm Hg (range 30 to 60 mm Hg). Each patient under went cardiac catheterization, and retrograde IMA flow was demonstrated in 100%. Arteriography confirmed the presence of a proximal high-grad e (>75%) subclavian stenosis in all patients. Stress thallium scanning was performed in two patients and demonstrated anterolateral ischemia in both. Operative intervention in four patients consisted of a left carotid-subclavian bypass using an 8 mm synthetic graft. There was no perioperative morbidity or mortality. Postoperative thallium scanning revealed resolution of the ischemic process. The average length of fol low-up was 20 months (range 12 to 25 months) with all patients remaini ng asymptomatic. The one patient who refused surgery died at 12 months . When IMA grafting is contemplated, proximal subclavian stenosis shou ld be suspected if there is >20 mm Hg systolic pressure differential b etween the arms. Arch arteriography should then be performed. Likewise , coronary-subclavian steal syndrome should be suspected in any patien t with an IMA graft who develops new cardiac symptoms and in whom a br achial pressure differential is detected. In most cases a carotid-subc lavian bypass graft provides a safe and durable solution.