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 secondary to proximal subclavian artery stenosis is an infrequent but increasingly recognized clinical entity and has been termed the ''coronary-subclavian steal syndrome.'' We report on five patients with this syndrome. All were men. The average age was 65 years (range 56 to 68 years). The mean interval from coronary bypass to presentation was 7.8 years (range 1 month to 18 years). Three patients presented with unstable angina and one with congestive heart failure. One patient was asymptomatic from a cardiac standpoint. The mean arm systolic blood pressure differential was 45 mm Hg (range 30 to 60 mm Hg). Each patient underwent cardiac catheterization, and retrograde IMA flow was demonstrated in 100%. Arteriography confirmed the presence of a proximal high-grade (>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 follow-up was 20 months (range 12 to 25 months) with all patients remaining asymptomatic. The one patient who refused surgery died at 12 months. When IMA grafting is contemplated, proximal subclavian stenosis should be suspected if there is >20 mm Hg systolic pressure differential between the arms. Arch arteriography should then be performed. Likewise, coronary-subclavian steal syndrome should be suspected in any patient with an IMA graft who develops new cardiac symptoms and in whom a brachial pressure differential is detected. In most cases a carotid-subclavian bypass graft provides a safe and durable solution.