The place of carotico-subclavian bypass surgery in angina treatment.

Coronary-subclavian steal syndrome results from atherosclerotic disease of the proximal subclavian artery, causing reversal of flow in an internal mammary artery used as conduit for coronary artery bypass. In the present case, we discussed the diagnosis and the treatment of coronary steal syndrome in a patient hospitalized due to decompensated cardiac insufficiency.

INTRODUCTION

The development of proximal subclavian stenosis may lead to reversal of flow from the left internal mammary artery (LIMA) to subclavian artery resulting in coronary artery disease known as coronary-subclavian steal syndrome (CSSS).[1] This rare complication of cardiac revascularization leads to recurrence of myocardial ischemia. When feasible, subclavian angioplasty and/or stent placement can provide acceptable result for these patients. Vascular reconstruction through carotid to subclavian artery bypass has been the standard procedure of choice. Other interventions in literature include axilloaxillary bypass and subclavian carotid transposition. The use of LIMA is recommended as a coronary bypass graft due to its excellent long-term results. Besides, CSSS might be seen depending on stenosis in proximal subclavian artery and escape of the flow back to the subclavian artery from LIMA.

This case report describes the use of carotid-subclavian artery bypass for the treatment of CSSS.

CASE REPORT

A 54-year-old male was admitted to our hospital with complaints of severe dyspnea, inability to lie in supine position, decrease in effort capacity, and pain in the left arm. Physical examination revealed tachycardia and 3/6 apical systolic murmur; bilateral rales in lower lung zones. Brachial, axillary, and radial pulses of the left arm were not palpable but were clearly palpated over the right arm. Lower extremity pulses were palpable. Past medical history revealed that he underwent coronary bypass graft operation five years prior to presentation.

He was assessed to have New York Heart Association Functional Classification Class III-IV, with a clinical diagnosis of ischemic cardiomyopathy (CMP), decompensated heart failure. An echoacradiogram was performed which showed increased left ventricular diameter and left ventricular ejection fraction of 18% by the modified Simpson method. He was started on diuretic and vasodilator treatment with regression of failure symptoms. However, he continued to have symptoms of angina and left arm pain responsive to isosorbide dinitrate. A differential diagnosis of CSSS was considered and patient underwent coronary angiography. It was observed on coronary angiography that point of origin of the left subclavian artery in the aorta was totally congested beginning from approximately 1 cm proximal [Figure 1]. A vertebral artery angiography was showed subclavian in bridge collaterals and flow to LIMA were observed in late period.

Figure 1

Coronary-subclavian steal

Using a ringed polytetrafluoroethylene (PTFE) graft (Vascutek, Germany) with a diameter of 6 mm, a left carotid-subclavian bypass was performed on the patient in elective conditions. Carotid shunt was not used while systemic heparin (5000 units) was administered during the operation. Postoperatively, a good graft pulse was felt in addition to easily palpable left upper extremity pulses. There were no complications. Following the operation and in the postoperative period, the complaints of the patient related to chest pain, dyspnea, and left arm pain progressively decreased. The patient was discharged on the postoperative day 5. Control coronary-subclavian angiogram 1 month later revealed an intact PTFE graft between carotid and subclavian artery [Figure 2].

Figure 2

Control carotico-subclavian angiogram (1 month later)

DISCUSSION

The coronary subclavian steal syndrome is an uncommon but well-recognized occurrence following coronary artery by-pass surgery using the internal mammary artery. In CSSS, the dilatation in the proximal region of the subclavian artery, depending on atherosclerosis in general, reduces LIMA blood flow and subsequently a back flow (steal) from the coronary artery to subclavian artery occurs.[12]

CSSS may develop quietly and also may cause angina, left arm ischemia, myocard infarction, and cardiac insufficiency.[3] Proximal aortic arch arteriography is the golden standard in the diagnosis of subclavian stenosis. Alternatively, Doppler, duplex ultrasonography, or magnetic resonance angiography could be used.[4]

Various methods have been identified in CSSS treatment. Endovascular stent and balloon might be performed radiologically, whereas carotid-subcalvian and subclavian-subclavian bypass operations might be performed surgically. There are situations where several of these treatments could be applied in a combined manner. Although the treatment methods applied radiologically has advantages regarding short hospitalization period and patient comfort, attempt failure, insufficient flow, restenosis (40.7% in early period), and the frequency of a secondary operation required in early period constitutes the disadvantages.[5]

Surgical methods are still preferred more commonly due to their easy application and good results. In 1994, Vitti, et al.,[6] reported their experiences in extrathoracic reconstruction as a treatment for subclavian steal syndrome. The patency rates at 5 and 10 years for carotid-subclavian bypass were about 94%, which compares favorably with the 66-89% patency rates for axilloaxillary bypass surgery.[47]

Although carotid-subclavian transposition has been reported to have a 7-year patency rate of 100%, the potential aggravation of coronary ischemia during the interruption to vertebral and internal mammary artery blood flow is an obstacle to the use of this option.[8]

In our case, the patient developed symptoms more than 5 years after coronary artery bypass graft (CABG). Since the stenosis was very close to the vertebral artery, there was a risk of occlusion during stenting. Therefore, bypass grafting was chosen in preference.

Carotid-subclavian artery bypass is considered the standard surgical treatment for symptomatic occlusion of proximal subclavian artery.[89] However, preparing an atherosclerotic subclavian artery in our patient for anastomosis was not feasible. In addition, exposure of the subclavian artery and bypass grafting to it through supraclavicular approach is not without technical difficulty, especially with the close proximity to important lymphatic channels and nerves. On the contrary, infraclavicular exposure of the axillary artery is a straightforward technique routinely performed by vascular surgeons and eliminates some of the potential risks of supraclavicular approach.

CONCLUSION

CSSS should be considered in patients presenting with recurrent chest pains after CABG with in situ left internal mammary grafts. Surgical extra-anatomical bypass is an effective method of treating this uncommon condition when percutoneous transluminal angioplasty is not possible. In experienced hands, carotid subclavian artery bypass remains the standard surgical procedure of choice. Carotid axillary artery bypass can be a feasible alternative when the traditional procedures are technically difficult.