Coronary Subclavian Steal Syndrome and Acute Anterior Myocardial Infarction
A New Treatment Dilemma in the Era of Primary Percutaneous Coronary Intervention
Coronary subclavian steal syndrome (CSSS) is an uncommon complication after coronary artery bypass graft (CABG) surgery using the left internal mammary artery (LIMA).1–3 CSSS results from the retrograde blood flow through the LIMA graft in the left subclavian artery (SCA), consecutive to a proximal SCA stenosis or total occlusion. CSSS usually manifests as stable angina pectoris1 but also rarely presents as ST-segment–elevation myocardial infarction secondary to an acute SCA occlusion or plaque rupture.1,2 Anterior ST-segment–elevation myocardial infarction resulting from an acute thrombotic occlusion of the left anterior descending (LAD) artery at the LIMA-to-LAD anastomotic site in a patient with concomitant CSSS may be a challenging problem during primary percutaneous coronary intervention and has not been reported to date.
Here, we report on a 62-year-old woman with hypertension, dyslipidemia, and peripheral artery disease who underwent CABG surgery using a LIMA graft to the LAD 12 years earlier (Figure 1 and Movie I in the online-only Data Supplement). The patient presented to the emergency department with de novo exertional chest pain. The 12-lead ECG showed negative T waves in the anterior leads, and her cardiac biomarkers were normal. During admission, the patient developed chest pain at rest associated with paresthesias of the left hand. An ECG showed new anterior ST-segment elevation, and the patient was transferred for primary percutaneous coronary intervention. The left coronary angiogram (Movie II in the online-only Data Supplement) showed a patent LAD with critical stenosis at the site of the LIMA-to-LAD anastomosis (Figure 1) and an unexpected retrograde flow through the patent LIMA graft to the left SCA (Figure 1). Interestingly, no angiographically significant stenosis was visualized on the proximal native LAD. An angiogram of the aortic root revealed total occlusion at the origin of the left SCA (Figure 1 and Movie III in the online-only Data Supplement), which, combined with the retrograde flow through the LIMA, confirmed the presence of CSSS with vascularization of the left upper limb depending on the reversed flow through the LIMA graft. Primary percutaneous coronary intervention to the LAD was performed with a drug-eluting stent across the LIMA-to-LAD anastomotic site. The final coronary angiogram (Movie IV in the online-only Data Supplement) demonstrated a restored anterograde flow from the proximal to the distal LAD and a preserved retrograde flow through the LIMA graft to the left SCA (Figure 1). Physical examination revealed a weaker left radial pulse, but plethysmography confirmed a biphasic pulse wave at the level of the left upper limb. An urgent Doppler ultrasonography showed occlusion of the left SCA and CSSS with reversed flow in the LIMA and anterograde flow in the left vertebral artery. No critical left upper-limb ischemia was documented, and conservative management was suggested. Computed tomographic angiography demonstrated a 15-mm total occlusion at the origin of the left SCA (Figure 2) and anterograde flow in the SCA through the patent LIMA graft. The left vertebral artery arose from the left SCA after the occlusion, and a focal 2.6-mm total occlusion was noted on the right SCA. A cardiac magnetic resonance imaging showed total occlusion at the origin of the left SCA (Figure 2 and Movie V in the online-only Data Supplement) and preserved left ventricular systolic function without inducible myocardial ischemia, thus excluding a coronary steal phenomenon in the territory of the distal LAD. The clinical course was uneventful, and the patient was discharged on day 3. The control Doppler ultrasonography at 3 months showed a monophasic flow in the left SCA and a reversed flow in the left vertebral artery without signs of left upper-limb ischemia. A conservative management was advocated. At the 1-year follow-up, the patient remained free from angina, left arm claudication, and neurological symptoms.
CABG surgery with the LIMA is nowadays considered the gold standard technique for surgical myocardial revascularization because of the improved long-term patency and lower perioperative and postoperative mortality rates.3 CSSS is a rare complication, occurring in 0.2% to 6.8% of patients referred for CABG surgery with the LIMA,1–3 but its prevalence is currently rising as a result of the increased use of the LIMA for CABG procedures. CSSS results most commonly from an atherosclerotic stenosis of the proximal left SCA, whereas pathologies such as Takayasu, giant-cell, or radiation-induced arteritis are infrequent causes.1,2 CSSS has also been reported in the presence of an arteriovenous hemodialysis fistula in the left arm.1,2 Percutaneous transluminal angioplasty and peripheral stenting of the proximal left SCA, before or after CABG surgery, may be a valuable therapeutic option associated with a low risk and excellent clinical outcomes.1,3,4 Anterior ST-segment–elevation myocardial infarction resulting from an acute left SCA occlusion in patients with CSSS after CABG has been described previously.1 We report here on a patient with unrecognized CSSS complicating previous CABG surgery with the LIMA several years earlier who presented with anterior ST-segment–elevation myocardial infarction resulting from an acute thrombotic occlusion of the native LAD at the LIMA-to-LAD anastomotic site. In our case, the patient was referred for CABG surgery without functional assessment of an angiographically intermediate ostial stenosis of the LAD, and the LIMA graft remained patent, probably as a result of the progression of an unrecognized atherosclerotic disease of the left SCA at the time of CABG, thus allowing vascularization of the left upper limb by the retrograde flow from the LAD into the left SCA. Our case highlights the importance of a systematic documentation of myocardial ischemia before proceeding to myocardial revascularization procedures and a routine preoperative screening of SCA stenosis before CABG surgery with either the LIMA or the right internal mammary artery, particularly in patients with multiple risk factors for peripheral artery disease or with a hemodialysis fistula in the left arm. Preoperative noninvasive imaging modalities, including Doppler ultrasonography, computed tomographic angiography, cardiac magnetic resonance, and angiograms of the aortic arch or the left SCA at the time of the diagnostic coronary angiogram, are potential diagnostic methods to avoid this challenging treatment dilemma, which may occur with increasing prevalence during primary percutaneous coronary intervention and potentially lead to acute left upper-limb ischemia.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.015226/-/DC1.
- © 2015 American Heart Association, Inc.