Incidence of coronary-subclavian steal syndrome in patients undergoing noncardiac surgery.

OBJECTIVE: To identify the incidence of coronary-subclavian steal syndrome in patients undergoing noncardiac surgery.

DESIGN: Prospective.

SETTING: Veterans Affairs Medical Center and university-affiliated medical center.

PARTICIPANTS: Adult patients with prior coronary artery bypass graft surgery and documented use of an internal mammary artery.

INTERVENTIONS: Bilateral simultaneous brachial blood pressures were determined noninvasively. The presumptive diagnosis of ipsilateral subclavian artery stenosis and coronary-subclavian steal syndrome was made if the systolic blood pressure differential was >20 mmHg.

MEASUREMENTS AND MAIN RESULTS: The presumptive diagnosis of ipsilateral subclavian artery stenosis based on a blood pressure differential was made in 6 of 86 (5%) patients screened. The diagnosis of coronary-subclavian steal syndrome was confirmed at cardiac catheterization by observing retrograde internal mammary artery flow in 3 patients or lack of internal mammary artery flow in 1 patient (3.4%). All 4 patients with angiographic confirmation had either angina or silent ischemia. Three patients had successful carotid subclavian bypass, and 1 patient refused surgery. Two patients had no evidence of myocardial ischemia and underwent their planned procedure without incident.

CONCLUSION: Coronary-subclavian steal syndrome occurs with relative frequency in noncardiac surgery patients with prior coronary artery bypass graft surgery using internal mammary artery conduits. Bilateral blood pressure measurements should be routinely performed during the preoperative evaluation. A pressure differential >20 mmHg should suggest the possibility of coronary-subclavian steal syndrome.