Unusual suspect-coronary subclavian steal syndrome caused severe myocardial ischemia

Coronary-subclavian steal syndrome represents a reversal of blood fl ow in left internal mammary artery. Th e most common cause of the syndrome is atherosclerotic disease in the ipsilateral, proximal subclavian artery. We present a case of  years old male, who developed severe anginal and neurological complaints three years after coronary artery bypass graft surgery(CABG). ©  Association of Basic Medical Sciences of FB&H. All rights reserved


INTRODUCTION
Coronary subclavian steal syndrome was described for the fi rst time in the  by Harjola and Valle [].Atherosclerosis is the most common cause of the steal syndrome.Takayasu's arteritis, radiation arteritis, giant cell arteritis, congenital aortic abnormalities and thoracic outlet syndrome have also been reported as possible causes.When left internal mammary artery (LIMA) is used as conduit for left anterior descendent artery (LAD), stenosis of the subclavian artery, proximal to the origin of the LIMA reverse the fl ow in the LIMA and steal blood from the coronary circulation causing myocardial ischemia.Also, reversal fl ow is possible in vertebral artery, causing neurological symptoms.Incidence after CABG, as reported by Tyras et al. [] in  is about . and in  Marques et al. [] reported .-..Recent studies showed that prevalence of significant subclavian stenosis before the CABG surgery is .-.[, ].Coronary-subclavian steal syndrome was initially reported to be rare, but due to increasing use of LIMA as LAD conduit increasing incidence of this entity is observed in past years.

CASE REPORT
Male,  years old experienced severe, persistant restrosternal pain at rest  hours before hospital admission.He had CABG surgery three years ago (LIMA to LAD and saphenous vein graft (SVG) to obtuse marginal branch (OM).After surgery, he was free of symptoms for one year and then he starting to experience exertional angina.His angina complaints increased during the time, and in past - months he had angina at rest, and used nitro-glycerine spray every day.In past medical history: percutaneous transluminal angioplasty (PTA) of left a. femorallis superfi cialis eleven years ago, partial resection of abdominal aortic aneurysm ( x  mm diameter) and by pass aorto-a.iliaca externa dex-a.femoralis communis sin.was done three years ago.Patient also reported neurological complaints starting one year after CABG, dizziness and headache, and paresthesia in left hand.Physical examination at admission revealed that blood pressure measured from the right arm was / mmHg, and from the left arm was / mmHg.Radial pulse was also weaker on the left arm.-lead ECG showed signs of left ventricle hypertrophy, Q waves in III, AVF, signifi cant ST segment depression and inverted T waves in I, II, V, V and V leads.Laboratory findings for myocardial necrosis were negative -(TnI level was ., lower limit is .).Left ventricle dilatation (ESD  mm, EDD  mm), reduced ejection fraction-, inferior wall akinesia and antero septal hypokinesia were demonstrated by -dimensional echocardiography.Coronarography was performed via right femoral ).Since the fi nding of concomitant, multivessel brachiocephalic disease is common in this entity [], we performed multislice computed tomography (MSCT) aortography a week after PTA.Other aortic arch vessels showed no signifi cant stenosis, but severe stenosis on ostioproximal subclavian artery remains after PTA (Figure ), so stent implantation is proposed to patient as a defi nitive treatment option.

DISCUSSION
Coronary subclavian steal syndrome is a rare complication of cardiac surgery.Th ere is a stenosis of the proximal por-   tion of the subclavian artery resulting in reversal of fl ow in an internal mammary artery graft and subsequent ischemia in the territory it supplies.Th e subclavian arterial stenosis produces a negative pressure gradient between the subclavian and internal mammary artery graft.Subsequent retrograde fi lling of the subclavian artery via the internal mammary graft causes the subclavian to "steal" blood from the coronary circulation [].Since LIMA graft is widely and increasingly used as LAD conduit, there are more reports of this entity.Th is cause of myocardial ischemia after complete CABG revascularisatin was often unrecognized in the past.Typical symptom is angina pectoris, but few cases of myocardial infarction are also reported [].In some cases, like in our case, neurological symptoms due to vertebrobasilar insuffi ciency like headache, dizziness, blurred vision are present.Inter arm pressure diff erence ≥  mm Hg in patients who are candidates for coronary bypass surgery has a sensitivity of approximately  and a specifi city of  for detecting subclavian artery stenosis [].Proximal aortic arch and direct subclavian artery arteriography are can easily be performed during coronarography, and they represent efficient diagnostic tool.Alternative diagnostic procedures are doppler, duplex ultrasonography, CT, or magnetic resonance [, ].

CONCLUSION
Treatment options for stenosis or occlusion of the subclavian artery are percutaneous transluminal angioplasty with stent implantation, or surgical treatment (aorta-subclavian bypass, carotid-subclavian bypass, axillo-axillary bypass, depending anatomy).Long term patency is showed after surgical interventions, since they were fi rst introduced as treatment options.But, in past years, the number of patients treated with percutaneous interventions and stent implantation is increasing.Patient preferences for percutaneous treatment is easy to explain: percutaneous treatment is less invasive and has a shorter hospital stay than surgical treatment.Both the immediate results and the long-term outcomes after balloon dilatation and stenting for stenotic lesions are excellent.However, when treating occluded subclavian arteries it is preferable to use a stent, since the restenosis rates of simple balloon dilatation remain high.Th e published reports of percutaneous treatment of coronary subclavian steal syndrome reveal excellent technical success rates with good long-term clinical benefi t.Although surgical treatment remains feasible, percutaneous revascularization of the subclavian artery both proximal and distal to the origin of the vertebral artery is now the treatment of choice in the management of subclavian steal syndromes [].In our case, we opted just for PTA since we did not have adequate stent size at that moment.As it is showed on MSCT follow up one week later, result is not satisfactory and a defi nite treatment option is stent implantation.

DECLARATION OF INTEREST
No confl ict of interest.
approach.It revealed LAD occlusion in mid part, proximal occlusion of right coronary artery (RCA) and OM branch.SVG for OM was patent, anastomosis and native artery without signifi cant stenosis.Operator tried to canulate left subclavian artery(LSA), but unsuccessful.After lot of eff orts, aortography was performed, LSA ostial suboclusion was demonstrated (Figure .).Aortography also revealed aortic dissection due to aggressive catheter manipulation.It is decided to canulate left radial artery, due to LIMA visualisation and further decision making.It was done with lot of care, due Allen's modifi ed test was positive.Despite the risk, we managed to make angiography and LIMA graft was patent, distal anastomosis and native artery without signifi cant lesions.PTA of LSA ostial stenosis was performed with semi compliant balloon BALTON x mm insuffl ated at / atm, signifi cant recoil was present (Figure .).PCI was not performed because we did not have adequate dimension of peripheral stent.Final angiography showed - of residual stenosis (Figure .