P219 The role of color-coded duplex sonography in evaluating coronary-subclavian steal syndrome

Background Coronary-subclavian steal syndrome is a rare phenomenon leading to dysfunction of left internal mammary artery (LIMA)-graft after coronary artery grafting with the occurrence of proximal stenosis of the left subclavian artery (LSA), which causes myocardial ischemia due to a blood-steal phenomenon through a fully patent LIMA-graft. Purpose To evaluate the role of color-coded duplex sonography (CCDS) in follow-up of all symptomatic patients with LIMA-graft after aorto-coronary bypass grafting (ACBG). Methods Two men and one woman with recurrence of angina pectoris symptoms and vertigo after ACBG with LIMA-LAD graft. Patients were hospitalized in cardiology for coronary graft assessment via selective coronary arteriography. Due to the discovery of fully patent grafts with a combination of varying degrees of proximal stenosis of the LSA, CCDS with a high-frequency linear probe was used to evaluate cervical arteries, LSA and the LIMA-graft flow rate applying functional probe for hyperemia (PH) of the left upper limb for hemodynamic assessment of significance of the steal syndrome. Results One woman at age 72 after ACBG – LIMA-LAD; RM1; RCA -s.v.g. Selective coronary arteriography showed patent bypass grafts with 70% proximal stenosis of LSA. The performed CCDS showed a LIMA-graft blood flow reduction from 36 ml/min to 12 ml/min in a sample for left upper limb hyperemia. There was a difference in the blood pressure of the upper limbs within 20 mmHg. Dobutamine stress echocardiography was performed, confirming ischemic zones in the LAD- peak segments. A 63 year old man after ACBG x 4 with a difference in blood pressure of upper limbs within 40 mmHg. The performed CCDS showed thrombosis of the left internal carotid artery, high-grade stenosis of the right internal carotid artery, high-grade stenosis of LSA, alternating blood flow in the left vertebral artery – a sign of hemodynamically significant steal syndrome. A 65 year old male after ACBG x 3 (LIMA-LAD, RCA, OM1 -s.v.g.). The selective coronary arteriography showed patent LIMA-graft with 50% proximal stenosis of LSA with a trans-stenotic pressure gradient of 20 mmHg. To identify the steal phenomenon we used CCDS, which showed a blood flow reduction into the LIMA-graft from 14.2 ml/min to 7.5 ml/ min - data of hemodynamically significant steal syndrome. Patients were treated with percutaneous transluminal angioplasty and stenting of the LSA with postprocedure reduction of angina pectoris complaints, no difference in the blood pressure of upper limbs and no reduction of LIMA-graft blood flow during the probe for hyperemia of the upper limb. Conclusion(s) Color-coded duplex sonography is an important and indispensable technique, part of the overall assessment of hemodynamics in case of coronary-subclavian steal syndrome and probably may prove to be a first method of choice in follow-up of all symptomatic patients with LIMA-LAD graft.