Journal of Education For Residents And Fellows in Surgery

Coronary-subclavian Steal Syndrome Status Post Coronary Artery Bypass Graft Via the In-situ Left Internal Mammary Artery

Mauricio Szuchmacher, MD | Tyler Bedford, MD | Ana Paula de Oliveira Pereira, MD | Hamida Tasneem, MS IV | Shailraj Parikh, MS IV | Neil Parikh, MD | Michael Cicchillo, MD |

Western Reserve Health Education - Northside Medical Center - Youngstown, OH

Journal:

 

Abstract:

Patients who have multivessel coronary artery stenosis on catheterization are good candidates for Coronary Artery Bypass Graft because stenting is less efficacious in reducing mortality when involving more than two coronary vessels. We present a patient who complains of chest pain status post coronary artery bypass graft using the left internal mammary artery over 10 years prior. The patient is diagnosed with coronary-subclavian steal syndrome via Doppler ultrasound and catheterization. The patient is treated surgically via carotid distal subclavian/axillary bypass grafting due to extensive stenosis of the subclavian graft.

Introduction

In coronary artery bypass graft surgery (CABG), the in-situ left internal mammary artery (LIMA), is recommended and commonly used as a graft to the left anterior descending (LAD) due to its proximal bifurcation from the left subclavian artery and its patency rate of 85% at 10 years 1. The development of proximal subclavian stenosis may cause decreased anterograde flow to the LIMA and therefore its anastomosis with the LAD, resulting in angina.

Figure 1: Doppler exam of the LUE: non-occlusive atherosclerotic plaque in medial aspect of the left subclavian artery.

Figure 1: Doppler exam of the LUE: non-occlusive atherosclerotic plaque in medial aspect of the left subclavian artery.

Case Presentation

A 73-year-old Caucasian male presented to the emergency department complaining of chest pain. The pain occurs at rest and is not relieved after taking three tablets of sublingual nitroglycerin. The pain was pressure-like, substernal, and radiating down his right arm. He has a past medical history of CABG in 1978 and 1986 with LIMA to LAD, saphenous vein grafts to circumflex marginal and diagonal branch of LAD and cardiac stents in 1995. Patient also had right-sided carotid endarterectomy (CEA) in 1995 and left-sided CEA in 2004, chronic obstructive pulmonary disease (COPD) secondary to asbestos exposure, bilateral hip surgeries, hyperlipidemia, and diabetes mellitus (DM), and occasional alcohol use. He was high risk based on his elevated thrombolysis in myocardial infarction (TIMI) score.

Figure 2: Arterial flow showing diminished peak systolic velocity within axillary artery.

Figure 2: Arterial flow showing diminished peak systolic velocity within axillary artery.

On admission, his vital signs were stable and physical exam was normal. His pulses were diminished in his left arm with numbness, tingling, and weakness when compared to his right arm. He underwent cardiac catheterization, which revealed left subclavian artery stenosis. The LAD and circumflex were completely occluded with a patent stent within the large circumflex marginal branch. Arterial Doppler of the left upper extremity revealed non-occlusive plaque in the medial segment of the subclavian and decreased velocity in the axillary artery. The patient underwent a left common carotid– subclavian/axillary bypass with ringed 8 mm polytetrafluorethylene (PTFE). The patient had an uneventful recovery in the surgery intensive care unit (SICU) and was discharged 3 days following the operation.

Figure 3: Severe multivessel coronary artery disease (CAD). Chronic occlusions of the ostial LAD and proximal circumflex with only patent vessel on the left being a marginal branch, which has a patent stent. Non-dominant right coronary artery remains patent and provides collaterals to the circumflex.

Figure 3: Severe multivessel coronary artery disease (CAD). Chronic occlusions of the ostial LAD and proximal circumflex with only patent vessel on the left being a marginal branch, which has a patent stent. Non-dominant right coronary artery remains patent and provides collaterals to the circumflex.

Discussion

Coronary subclavian steal syndrome is an uncommon complication of CABG when the LIMA is involved 2. Incidence is 0.07-3.4% 3. due to the distal end of the LIMA and its anastamosis with one of the coronary arteries, in this case and most cases, the LAD. After anastamosis of the LIMA graft to the LAD is complete, the vascular section between the subclavian and coronary artery assumes coronary blood flow and stenosis in any part of the vascular section can cause angina 4. In left subclavian artery stenosis, Myocardial infarction (MI) may occur due to the reversal flow in the coronary-subclavian anastamosis 5. Blood flow can reverse from the vertebral artery or from the LIMA, which can also cause cardiac ischemia symptoms 4.

Coronary subclavian steal syndrome can present as asymptomatic 6, recurrent angina after tension to the upper limb, myocardial infarction, silent ischemia, or heart failure 7. Symptoms of this uncommon complication can present as early as 2 years and reported as late as 31 years following surgery. If symptoms such as recurrent angina present within a year after a CABG involving LIMA, it is highly likely that the diagnosis of subclavian stenosis was missed during the surgery 8. There is a 3:1 prevalence of symptomatic subclavian stenosis on the left subclavian compared to the right subclavian artery 4. Cinar et al. reported 72.5% stenosis in the left subclavian compared to 27.5% stenosis in the right subclavian with patients who had subclavian steal syndrome 4. More importantly, those with coronary subclavian syndrome all had left subclavian lesions.

Coronary subclavian steal syndrome should especially be noted as a differential in those with history of peripheral vascular disease 7. The most common risk factor for coronary subclavian steal syndrome is atherosclerosis. Other possible causes of CSSS include aortic arch syndrome, congenital aortic anomalies, and compression at the superior thoracic outlet 9.

Figure 4: Chronically-occluded vein graft to the circumflex system. Widely-patent left IMA bypass graft to the LAD.

Figure 4: Chronically-occluded vein graft to the circumflex system. Widely-patent left IMA bypass graft to the LAD.

The gold standard for diagnosing subclavian stenosis is an arteriography. However, alternative methods for diagnosing are also practiced, such as arterial Doppler, duplex ultrasonogram or magnetic resonance imaging (MRI) 9. Difference in systolic blood pressures measured in both arms is a diagnostic clue for coronary subclavian steal syndrome. Those with predominant arm ischemia symptoms have a systolic blood pressure difference of 40 mmHg to 50 mmHg. However, the pressure difference in both arms is diagnostic 42% of the time 4. Majority of the literature approves Doppler ultrasonogram (USG) as a screening test in suspected cases. A confirmatory arteriography should be performed if Doppler USG is positive 4.

As for treatment, there are several options involving an endovascular approach such as: Percutaneous transluminal balloon angioplasty (PTA) and stenting. Stenting is recommended more often because of fewer complications, the procedure being less invasive, lower morbidity and mortality, and excellent short-term outcome when compared to its surgical counterpart.

According to the retrospective study of Cinar et al. the primary patency rates at 1 year, 5 years, and 10 years after carotid-subclavian bypass with PTFE graft procedure, are 98%, 91%, and 47%. The overall survival rate at 1 year is 100%, 3 years is 95%, 5 years is 93%, and at 10 years is 38% 4.

In this case, the patient became symptomatic more than 10 years after undergoing CABG. Due to the proximity of stenosis in the subclavian graft to the vertebral artery, there was an increased risk of occlusion during stenting making bypass grafting more preferable. Also, due to the extensive stenosis of the subclavian graft, carotid distal subclavian/axillary bypass grafting was performed alternatively.

Conclusion

Patients presenting with recurrent chest pains after a CABG using in situ LIMA should have coronary subclavian steal syndrome as part of the differential diagnosis. Coronary subclavian steal syndrome causes retrograde flow to the LIMA and its anastomosis to the LAD resulting in angina. An effective method in treating these patients is with carotid- subclavian bypass.

References

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