Coronary subclavian steal syndrome due to thrombosis of the left subclavian artery aneurysm: a case report

Abstract

Background: Coronary subclavian steal syndrome (CSSS) is an often easily overlooked cause of angina that may occur after a coronary artery bypass graft (CABG) procedure. The onset of CSSS several years after coronary revascularization has been described in case reports, and in the few retrospective reviews that compare the endovascular approach with surgical treatment. Subclavian stenosis can naturally coincide with coronary artery disease and may already be present during the initial CABG.

Case summary: A 59-year-old male with a history of three-vessel disease who had a left internal mammary artery (LIMA) bypass graft, exhibited a gradual worsening of angina that coincided with numbness and impaired function of the left fingers, hand, and arm. Myocardial perfusion imaging showed reversible ischaemia, and coronary angiography suggested a thrombotic lesion proximal to the LIMA ostium. Calcified and partially thrombosed proximal left subclavian artery (LSA) aneurysm was visualized using computed tomography imaging, whereas Doppler ultrasound revealed a partially reversed vertebral flow. The lowest risk treatment was a bypass between the left common carotid artery and the LSA. The procedure was immediately successful, with cessation of symptoms and a favourable medium-term outcome.

Discussion: As no guidelines exist for such cases, the importance of multidisciplinary co-operation in diagnostics and devising a treatment plan is underlined. Moreover, screening for subclavian artery stenosis in CABG candidates should be warranted as part of the initial preoperative assessment.

Keywords: Case report; Coronary subclavian steal syndrome; Subclavian aneurysm; Subclavian stenosis.

Figure 1

Polar map images of myocardial perfusion at stress and at rest. A calculated polar map of perfusion reversibility. Reversible ischaemia in the left circumflex artery vascular region. Perfusion defect in the LAD supplied anterobasal region. No areas of significant perfusion deficiency at rest.

Figure 2

Coronary angiography. (A) Right coronary artery remains clotted, with slow collateral inflow. (B) No stenosis in left main (LM) coronary artery, dominant branch of LM is left circumflex artery of and proximal narrowing in left obtuse marginal (LOM) artery, total blockage in LAD. (C) Plausible subclavian aneurysm is suggested by vessel lumen narrowing and turbulent flow in proximal left subclavian artery. Left internal mammary artery graft is open—no narrowing is visible proximally (C) or distally (D). Sternotomy fixation is visible in all projections.

Figure 3

Preoperative Doppler-ultrasound of the left vertebral artery. Flow is inverted during systole.

Figure 4

Computed tomography angiography; preoperative (A and B) and postoperative (C and D) 3D reconstructions (A and C) and key CT (B and D) images of the subclavian aneurysm and surrounding vascular structures. Bypass graft (k) is open and functioning in the postoperative images (C and D). e: subclavian aneurysm, f: distal subclavian artery, g: left vertebral artery, h: left internal mammary artery-LAD graft, i: left carotid artery, j: cross-sections of the aneurysm (1–4; superior to inferior slice), and k: carotid-subclavian bypass graft.