Abstract
Coronary-subclavian artery (SCA) steal syndrome is an uncommon phenomenon in which coronary flow is diverted into the SCA through the patent left internal mammary artery (LIMA) conduit due to critical subclavian stenosis. The prevalence of significant left SCA (LSCA) stenosis in patients, referred for coronary bypass surgery, has been reported to be 0.2 to 6.8%. Most patients usually present with angina pectoris, and secondary myocardial infarction is rarely reported. Herein, we present a case of coronary bypass graft in which a left anterior descending artery-LIMA graft was applied to supply the left arm due to complete LSCA occlusion. The patient was hospitalized with a diagnosis of non-ST elevation myocardial infarction.
Keywords: steal syndrome, subclavian stenosis, acute coronary syndrome
Most patients with subclavian steal syndrome usually present with angina pectoris, and secondary myocardial infarction is rarely reported.1 2 Herein, we present a case of coronary bypass graft in which a left anterior descending artery (LAD)-left internal mammary artery (LIMA) graft was applied to supply the left arm due to complete left subclavian artery (LSCA) occlusion. The patient was hospitalized with a diagnosis of unstable angina. The assessed cardiac markers were above the cutoff points.
A 75-year-old male patient presented with unstable angina. He had undergone three-vessel coronary bypass surgery 9 years ago. Cardiac markers were increased, including creatine kinase MB and troponin-I (51.5 U/L and 1.64 ng/mL, respectively). Coronary angiography revealed the patent venous grafts anastomosed to the right coronary and circumflex artery and also a patent LIMA graft anastomosed to the middle LAD. However, there was retrograde flow through the LIMA and the left arm was supplied by retrograde flow from the LAD (Fig. 1B), since the LSCA was totally occluded from the osteal segment (Fig. 1A). The patient did not show any claudication of the left arm nor symptoms related to posterior cerebral circulation. There was a systolic blood pressure discrepancy of 30 mm Hg between the upper extremities. The asymptomatic clinical picture may be explained by the sufficient retrograde flow to the left arm, which can trigger myocardial infarction in the distal LAD territory. The EuroSCORE of the patient was calculated to be 14. We preferred interventional therapy initially. Graft stent implantation to the LAD and elective bypass surgery to the SCA was scheduled.
Fig. 1.
Anteroposterior projection showing (B) LAD-LIMA graft and circulation of the left arm and (A) subclavian artery occlusion. LAD, left anterior descending artery; LIMA, left internal mammary artery.
Coronary-SCA steal syndrome is an uncommon phenomenon in which the coronary flow is diverted into the SCA through the patent LIMA conduit due to critical subclavian stenosis.3 The prevalence of significant LSCA stenosis in patients referred for coronary bypass operation has been reported to be 0.2 to 6.8%. Most patients usually present with angina pectoris, and secondary myocardial infarction is rarely reported.1 2 Treatment strategies vary according to the clinical picture, includes a medical follow-up, and interventional approaches involving the SCA or LAD itself. Initially, a percutaneous intervention of either SCA or LAD can be preferred. Successful interventions to the SCA in similar clinical settings have also been reported.4 However, percutaneous intervention of chronic total occlusion of the SCA is still obscure. In our case, the SCA was totally occluded from the osteal segment and the occluded segment was relatively long. Therefore, we preferred the safer approach (i.e., percutaneous intervention of the LAD with graft stent deployment and subsequent surgical therapy for the SCA if necessary); however, the patient declined interventional treatment and followed up with medical therapy.
In conclusion, subclavian steal syndrome may rarely cause acute coronary syndrome. A preoperative SCA evaluation may prevent the development of such a clinical picture. The patient can be treated with interventional therapy through either a SCA or coronary artery approach according to anatomical applicability.
Acknowledgments
The authors do not report any conflict of interest regarding this work. This work was not supported by any company.
References
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