Prevalence and impact of the subclavian steal syndrome

Myocardial ischaemia due to subclavian stenosis after coronary artery bypass graft: a case report

Introduction

Subclavian artery stenosis occurs up to 4.6% in patients who are referred for a coronary artery bypass graft (CABG). Subclavian artery stenosis can compromise the blood flow in the ipsilateral mammary artery.

Case presentation

In this case report, we describe a patient with prior history of CABG and peripheral vascular disease, who presented with recurrent chest pain symptoms. Cardiac perfusion imaging using Rubidium-82 positron emission tomography showed extensive ischaemia in the anterior wall. Coronary angiography showed an ipsilateral (left) severe subclavian stenosis, while there was no significant stenosis in the bypass grafts. Patient’s symptoms resolved after percutaneous intervention of the left subclavian artery.

Discussion

The presence of subclavian artery stenosis can result in myocardial ischaemia after prior CABG utilizing the internal mammary artery. A history of peripheral vascular disease and a blood pressure difference between the upper extremities greater than 15 mmHg are clinical predictors of subclavian artery stenosis. Percutaneous angioplasty and stenting is considered the first-line treatment for subclavian artery stenosis. Surgical management should be considered after failure of endovascular treatment in low-surgical-risk patients.

Percutaneous endovascular therapy for symptomatic chronic total occlusion of the left subclavian artery

INTRODUCTION

Percutaneous endovascular therapy is an accepted and preferred procedure for symptomatic subclavian artery disease. However, the technical feasibility and effectiveness of treating chronic total occlusion of the subclavian artery with this approach is uncertain. We aimed to evaluate the initial and mid-term results of endovascular therapy for patients with symptomatic chronic total occlusion of the left subclavian artery.

METHODS

Consecutive patients who underwent balloon angioplasty and stenting for chronic total occlusion of the left subclavian artery between January 2010 and February 2014 were included.

RESULTS

Overall, 16 patients (10 male, 6 female; mean age 56 ± 13 years) underwent balloon angioplasty and stenting for chronic total occlusion of the left subclavian artery. 6 (37.5%) had arm claudication, 8 (50.0%) had vertebrobasilar insufficiency and 2 (12.5%) had coronary steal. 18 balloon-expandable stents were implanted in 15 patients. Central luminal passage was not achieved in one patient because of the subintimal position of the guidewire (procedural success rate 93.8%). There were no procedure-related complications. Mean preprocedural and postprocedural systolic blood pressure differences between the upper extremities were 37 ± 13 (range 25-60) mmHg and 11 ± 9 (range 5-38) mmHg, respectively; the improvement was statistically significant. Outpatient follow-up revealed one asymptomatic restenosis at two years. The patency rate at two years was 93.3%.

CONCLUSION

Balloon angioplasty and stenting for chronic total occlusion of the left subclavian artery is safe and effective, with good acute success rate and mid-term patency. Prospective randomised studies on larger patient populations would provide more precise results.

Clinical significance of reversal of flow in the vertebral artery identified on cerebrovascular duplex ultrasound

BACKGROUND

Reversal of flow in the vertebral artery (RFVA) is an uncommon finding on cerebrovascular duplex ultrasound examination. The clinical significance of RFVA and the natural history of patients presenting with it are poorly understood. Our objective was to better characterize the symptoms and outcomes of patients presenting with RFVA.

METHODS

A retrospective review was performed of all cerebrovascular duplex ultrasound studies performed at our institution between January 2010 and January 2016 (N = 2927 patients). Individuals with RFVA in one or both vertebral arteries were included in the analysis.

RESULTS

Seventy-four patients (74/2927 patients [2.5%]) with RFVA were identified. Half of the patients were male. Mean age at the time of the first ultrasound study demonstrating RFVA was 71 years (range, 27-92 years); 78% of patients had hypertension, 28% were diabetic, and 66% were current or former smokers. Indications for the ultrasound examination were as follows: 44% screening/asymptomatic, 7% anterior circulation symptoms, 20% posterior circulation symptoms, 28% follow-up studies after cerebrovascular intervention, and 5% upper extremity symptoms. At the time of the initial ultrasound examination, 21 patients (28%) had evidence of a prior carotid intervention (carotid endarterectomy or carotid stenting), 21 patients had evidence of moderate (50%-79%) carotid artery stenosis (CAS) in at least one carotid artery, and 12 patients (16%) had evidence of severe (>80%) CAS. Of the 15 patients presenting with posterior circulation symptoms, 11 (73%) had evidence of concomitant CAS. In contrast, 22 of the 59 patients (37%) without posterior circulation symptoms had duplex ultrasound findings of CAS (P = .01). The mean duration of follow-up was 28 ± 22 months. Follow-up data were available for 63 patients (85%), including the 15 patients who presented with posterior circulation symptoms. Of these 15 patients, 5 underwent subclavian artery revascularization, including balloon angioplasty and stenting in 4 patients and open/hybrid revascularization in 1 patient. Five individuals were awaiting intervention. Three patients underwent carotid endarterectomy for CAS, with resultant improvement in posterior circulation symptoms. Finally, one patient was deemed too high risk for intervention, and one patient was found to have an alternative cause for symptoms. The remaining 59 patients continued to be asymptomatic during follow-up. One patient progressed to vertebral artery occlusion, and six patients had progression of CAS.

CONCLUSIONS

Symptomatic RFVA responds well to intervention, including subclavian artery stenting and carotid intervention in patients with CAS. The majority of patients with this finding are asymptomatic at the time of presentation. Although progression of vertebral artery disease is rare, these patients may benefit from monitoring for progression of CAS with surveillance ultrasound.

Simultaneous vertebral and subclavian artery stenting

Introduction

Vertebrobasilar territory ischemia leads to disabling neurological symptoms and may be caused both by vertebral artery (VA) and subclavian artery (SA) stenosis. The coexisting symptomatic ipsilateral VA and proximal SA stenosis should be considered as a true bifurcation lesion for percutaneous treatment.

Aim

To evaluate the safety and efficacy of simultaneous angioplasty of vertebral and subclavian stenosis.

Material and methods

Fifteen patients (age 69.5 years, 46.7% men, all symptomatic from posterior circulation (history of stroke, transient ischemic attack, chronic ischemia symptoms)) were scheduled for simultaneous SA/VA angioplasty. Clinical and duplex ultrasound follow-up was conducted 1, 6 and 12 months after the procedure.

Results

The technical success rate was 100%. Single balloon-mounted stent angioplasty was performed for all VAs and for 13 (86.7%) SAs. In 4 cases a simultaneous radial and femoral approach was required. The mean North American Symptomatic Carotid Endarterectomy Trial (NASCET) VA stenosis was reduced from 88.7 ±9.7% to 5.7 ±6.8% and SA stenosis from 80 ±12.2% to 11 ±12.3% (p < 0.01). No periprocedural death, stroke, myocardial infarction or transient ischemic attack occurred. During follow-up (range: 6–107 months) in 10 of 15 (66.7%) patients relief of chronic ischemic symptoms was observed. No stroke/TIA occurred. One cardiovascular and 2 non-cardiovascular deaths were recorded. There was 1 symptomatic vertebral and 1 subclavian in-stent restenosis, and 2 cases of asymptomatic VA in-stent occlusion occurred.

Conclusions

Simultaneous vertebral and subclavian artery stenting is safe and effective. The restenosis rate remains at an acceptable level and it may be treated successfully with drug-eluting balloon angioplasty. In selected patients a dual radial and femoral approach may facilitate the procedure.

Vascular Causes of Syncope: An Emergency Medicine Review

BACKGROUND

Syncope is a common emergency department (ED) complaint, accounting for 2% of visits annually. A wide variety of etiologies can result in syncope, and vascular causes may be deadly.

OBJECTIVE

This review evaluates vascular causes of syncope and their evaluation and management in the ED.

DISCUSSION

Syncope is defined by a brief loss of consciousness with loss of postural tone and complete, spontaneous recovery without medical intervention. Causes include cardiac, vasovagal, orthostatic, neurologic, medication-related, and idiopathic, and most cases of syncope will not receive a specific diagnosis pertaining to the cause. Emergency physicians are most concerned with life-threatening causes such as dysrhythmia and obstruction, and electrocardiogram is a primary means of evaluation. However, vascular etiologies can result in patient morbidity and mortality. These conditions include pulmonary embolism, subclavian steal, aortic dissection, cerebrovascular disease, intracerebral hemorrhage, carotid/vertebral dissection, and abdominal aortic aneurysm. A focused history and physical examination can assist emergency physicians in determining the need for further testing and management.

CONCLUSIONS

Syncope is common and may be the result of a deadly condition. The emergency physician, through history and physical examination, can determine the need for further evaluation and resuscitation of these patients, with consideration of vascular etiologies of syncope.

Treatment-Related Cardiovascular Outcomes in Patients with Symptomatic Subclavian Artery Stenosis

Background

Subclavian artery stenosis (SAS) is narrowing of the subclavian artery most commonly caused by atherosclerosis. It serves as a marker for cerebrovascular and myocardial ischemic events.

Methods

A retrospective cohort study was conducted to determine the association of treatment via combination therapy (antiplatelet drug plus either by-pass surgery or percutaneous transluminal angioplasty (PTA) with or without stent implantation) versus antiplatelet drug therapy alone on cardiovascular events and all-cause mortality in Marshfield Clinic patients diagnosed with symptomatic SAS from January 1, 1995 to December 31, 2009.

Results

Of the total 2153 cases, 100 patients were identified as eligible to be included in the study. Of these 100 patients that met inclusion criteria, 30 underwent combination therapy while 70 were managed only with drug treatment. A median length of follow-up was 8.45 years. Adverse cardiovascular events occurred in 5/30 (17%) of combination therapy patients compared to 28/70 (40%) of antiplatelet drug therapy only patients (p = 0.0355). Accordingly, all-cause mortality was higher (47%) in the antiplatelet drug therapy only group than the combination therapy group (13%) [hazard ratio = 3.45, p = 0.0218].

Conclusions

Preliminary findings in this pilot data set suggest that combination therapy (medications plus either surgical or interventional repair) of subclavian artery stenosis is associated with less cardiovascular adverse events and higher survival rates. However, prospective randomized studies with larger number of patients are needed to validate these findings.

Review of coronary subclavian steal syndrome

The clinical benefits of using the left internal mammary artery (LIMA) to bypass the left anterior descending artery are well established making it the most frequently used conduit for coronary artery bypass surgery (CABG). Coronary subclavian steal syndrome (CSSS) occurs during left arm exertion when (1) the LIMA is used during bypass surgery and (2) there is a high grade (≥75%) left subclavian artery stenosis or occlusion proximal to the ostia of the LIMA resulting in "stealing" of the myocardial blood supply via retrograde flow up the LIMA graft to maintain left upper extremity perfusion. Although CSSS was once thought to be a rare phenomenon, its prevalence has been underestimated and is becoming increasingly recognized as a serious threat to the success of CABG. Current guidelines are lacking on recommendations for screening of subclavian artery stenosis (SAS) pre- and post-CABG. We hope to provide an algorithm for SAS screening to prevent CSSS in internal mammary artery bypass recipients and review treatment options in the percutaneous era.

Successful Angioplasty of Left Vertebral Artery and Right Subclavian Artery Via Retrograde Approach

We describe a 77-year-old male who had right upper limb ischemic symptoms and history of unsuccessful right subclavian artery angioplasty. According to ultrasound findings, upper limb angiography was performed which confirmed stenosis of the left vertebral and right subclavian arteries. Percutaneous angioplasty and stenting of left vertebral and right subclavian arteries were performed in two separate sessions. Retrograde approach was scheduled for right subclavian artery angioplasty which is challenging due to potential risks to adjacent vertebral artery. This case reports underscores that percutaneous approaches may be preferential given their confirmed long-term efficacy and lower morbidity.

Penetrating neck injury: Collaterals for another life after ligation of common carotid artery and subclavian artery

Neck, being not protected by skeleton, is vulnerable to external trauma and injury which involves blood vessels, trachea, esophagus and other endocrine and nervous system organs. Vascular injuries can not only cause potentially life-threatening hemorrhage but also need profound surgical expertise in management. Development of collateral circulation in neck is well known; however, there is scarcity of literature on the role of collateral formation in neck trauma. Here, we present a unique case of penetrating gunshot injury to neck with right common carotid and right subclavian artery injury with hemorrhagic shock managed with ligation of these vessels as a life-saving procedure. The patient presented with no neurological or motor deficits in immediate postoperative period owing to the collateral circulation between right vertebral artery and right common carotid and right subclavian artery.

Where did the clot go? An unusual complication of mechanical thrombectomy caused by malignancy related subclavian steal phenomenon in a patient with acute basilar artery occlusion

Subclavian steal is a relatively common vascular phenomenon usually caused by atherosclerotic disease. While symptoms are rare, arm claudication of the ipsilateral limb is most common, with paroxysmal symptoms of vertebrobasilar insufficiency (often exercise induced) being relatively uncommon. Here we present a case of brachial artery embolism during mechanical thrombectomy for basilar artery thrombosis, secondary to subclavian steal phenomenon. This atypical and potentially irreversible complication should be considered in patients with acute ischemic stroke undergoing neurointerventional management when subclavian steal is discovered angiographically.

Where did the clot go? An unusual complication of mechanical thrombectomy caused by malignancy related subclavian steal phenomenon in a patient with acute basilar artery occlusion

Subclavian steal is a relatively common vascular phenomenon usually caused by atherosclerotic disease. While symptoms are rare, arm claudication of the ipsilateral limb is most common, with paroxysmal symptoms of vertebrobasilar insufficiency (often exercise induced) being relatively uncommon. Here we present a case of brachial artery embolism during mechanical thrombectomy for basilar artery thrombosis, secondary to subclavian steal phenomenon. This atypical and potentially irreversible complication should be considered in patients with acute ischemic stroke undergoing neurointerventional management when subclavian steal is discovered angiographically.

Endovascular Treatment of the Subclavian Artery Steno-Occlusive Disease

OBJECTIVE

The aim of our study was to compare immediate and long-term results of endovascular interventions for the treatment of steno-occlusive disease of subclavian arteries (SAs) depending on the length of lesion.

MATERIALS AND METHODS

Between 2010 and 2013, we performed 245 endovascular procedures to treat patients with atherosclerotic steno-occlusive disease of SAs. All patients were examined and subdivided according to the received results into 2 groups: 125 patients with stenosis of SA were included in the first group and 120 patients with occlusion of SA were included in the second group. The patients were then followed up at 6, 12, 24, 36, and 48 months after endovascular interventions. Follow-up visits contained symptomatic evaluation, clinical assessment with physical examination, complete neurological evaluation, and serial color Doppler ultrasonography.

RESULT

Transitory ischemic attacks in the vertebrobasilar system were intraoperatively developed by 1 patient from the first group (.8%) and 3 patients from the second group (2.5%). Reinterventions in the long-term period were carried out in 9 (7.2%) cases in the first group and 12 (10%) cases in the second group (P = .43). The cumulative primary stent patency at 4 years was 89.8% in the first group and 87% in the second group (P = .4).

CONCLUSIONS

In the case of SA occlusion on the first stage, it is expedient to carry out endovascular recanalization followed by stenting. Our study revealed an increased risk of stent thrombosis or in-stent restenosis in patients with stents >40 mm.

Multiterritory Atherosclerosis and Carotid Intima-Media Thickness as Cardiovascular Risk Predictors After Percutaneous Angioplasty of Symptomatic Subclavian Artery Stenosis

OBJECTIVES

To identify independent predictors of cardiovascular events among patients with subclavian artery stenosis.

METHODS

Two hundred eighteen consecutive patients with subclavian artery stenosis referred to angioplasty were examined for coexistent coronary, renal, or lower extremity artery stenosis of 50% or greater. Initial carotid intima-media thickness and internal carotid artery (ICA) stenosis were assessed. Intima-media thickness was reassessed in 108 randomly chosen patients to evaluate the change over time. The incidence of cardiovascular death, myocardial infarction (MI), ischemic stroke, and symptomatic lesion progression was recorded.

RESULTS

The patients included 116 men and 102 women (mean age ± SD, 62.1 ± 8.4 years). Isolated subclavian artery stenosis and involvement of 1, 2, and 3 or 4 other territories with stenosis of 50% or greater were found in 46 (21.1%), 83 (38.1%), 55 (25.2%), and 34 (15.6%) patients, respectively. Internal carotid artery stenosis of 50% or greater (relative risk [RR], 1.54; 95% confidence interval [CI], 1.39-1.70; P < .001) and initial intima-media thickness (RR, 1.16; 95% CI, 1.05-1.28; P = .005) were identified as independent markers of multiterritory atherosclerosis. The optimal intima-media thickness cutoff for atherosclerosis extent was 1.3 mm (sensitivity, 75.6%; specificity, 76.1%). During follow-up of 57 ± 35 months, cardiovascular death, MI, and ischemic stroke occurred in 29 patients (13.3%). Those patients had significantly higher intima-media thickness progression (+0.199 ± 0.57 versus +0.008 ± 0.26 mm; P = .039) and more widespread initial atherosclerosis (mean territories, 1.8 ± 1.1 versus 1.3 ± 1.1; P = .042). Independent predictors of cardiovascular death, MI, ischemic stroke, and lesion progression were coronary artery disease (RR, 1.32; 95% CI, 1.10-1.58; P = .003) and intima-media thickness progression (RR, 1.22; 95% CI, 1.02-1.46; P = .033; sensitivity, 75.0%; specificity, 61.8%).

CONCLUSIONS

In patients with symptomatic subclavian artery stenosis, baseline carotid intima-media thickness and ICA stenosis of 50% or greater are associated with multiterritory atherosclerosis, whereas intima-media thickness progression is associated with the risk of cardiovascular events.

Resolution of ischemic symptoms after percutaneous angioplasty for a symptomatic subclavian artery stenosis

OBJECTIVE

A minor part of patients with subclavian or innominate artery occlusive disease (subclavian artery stenosis [SAS]) experience symptoms of vertebrobasilar insufficiency, upper extremity exertional ischemia (UEEI), or cardiac ischemia owing to subclavian-coronary steal (SCS) in some instances. The study aimed to assess the impact of percutaneous transluminal angioplasty (PTA) of symptomatic SAS on symptom resolution and to determine factors related with SAS recurrence.

METHODS

Symptom resolution and incidence of restenosis (RS) were evaluated for up to 15 years in patients who had undergone successful PTA of SAS.

RESULTS

The study group comprised 232 consecutive subjects after successful PTA of SAS (61.9 ± 8.4 years old 53.4% men). The mean follow-up time was 101 ± 40 months (range, 5-188 months). One month after PTA, 85.4% of the study participants were free from dizziness, 94.4% from imbalance, 97.1% from visual disturbances, 97.8% from syncope, 98.7% from UEEI, and 100% from SCS. RS was found in 37 patients (15.9%) in long-term observation. UEEI, dizziness, imbalance, and SCS were significantly more frequent in patients with SAS recurrence, as compared with patients with patent artery (65.9% vs 3.1% [P < .001] 63.4% vs 19.4% [P < .001]; 26.8% vs 9.4% [P = .005]; and 100% vs 15.4% [P = .018], respectively). Smaller stent diameter (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.79-0.96; P = .004), implantation of ≥2 stents for a lesion (OR, 1.15; 95% CI, 1.05-1.26; P = .003), concomitant stenosis in the carotid or vertebral artery (OR, 1.10; 95% CI, 1.01-1.21; P = .036), high-sensitivity C-reactive protein level (OR, 1.20; 95% CI, 1.09-1.31; P < .001), and high-density lipoprotein level (OR, 0.91; 95% CI, 0.82-0.98; P = .021) were associated independently with risk of RS, whereas recurrence of UEEI (relative risk, 1.71; 95% CI, 1.55-1.90; P < .001), dizziness (OR, 1.26; 95% CI, 1.14-1.39; P < .001), limb paresthesia (OR, 1.14; 95% CI, 1.04-1.25; P = .005), and angina in subjects after coronary artery bypass grafting (OR, 1.11; 95% CI, 1.01-1.21; P = .024) were associated with RS/SAS progression after PTA.

CONCLUSIONS

Angioplasty of SAS leads to symptom resolution in most patients. UEEI, dizziness, and angina recurrence are predictors of RS or SAS progression; high-sensitivity C-reactive protein, smaller stent diameter, and number of implanted stents predict RS.

Computational modeling of blood flow steal phenomena caused by subclavian stenoses

The study of steal mechanisms caused by vessel obstructions is of the utmost importance to gain understanding about their pathophysiology, as well as to improve diagnosis and management procedures. The goal of this work is to perform a computational study to gain insight into the hemodynamic forces that drive blood flow steal mechanisms caused by subclavian artery stenosis. Such condition triggers a flow disorder known as subclavian steal. When this occurs in patients with internal thoracic artery anastomosed to the coronary vessels, the phenomenon includes a coronary-subclavian steal. True steal can exist in cases of increased arm blood flow, potentially resulting in neurological complications and, in the case of coronary-subclavian steal, graft function failure. In this context, the anatomically detailed arterial network (ADAN) model is employed to simulate subclavian steal and coronary-subclavian steal phenomena. Model results are verified by comparison with published data. It is concluded that this kind of model allows us to effectively address complex hemomdynamic phenomena occurring in clinical practice. More specifically, in the studied conditions it is observed that a regional brain steal occurs, primarily affecting the posterior circulation, not fully compensated by the anterior circulation. In the case of patients with coronary revascularization, it is concluded that there is a large variability in graft hemodynamic environments, which physically explain both the success of the procedure in cases of severe occlusive disease, and the reason for graft dysfunction in mildly stenosed left anterior descending coronary artery, due to alternating graft flow waveform signatures.

Treatment of subclavian artery stenosis: A case series

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Case presentation of a patient treated with subclavian artery stenting.

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Case presentation of a patient treated with transposition of the left subclavian artery onto the left common carotid artery.

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Case presentation of a patient treated with carotid- subclavian artery bypass with a PTFE graft.

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Case presentation of a patient treated with carotid to axillary bypass.

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Discussion and literature review of methods and indications of treatment of subclavian artery occlusive disease.

Introduction

In this case series, different modalities of treatment for patients with ischaemic symptoms of subclavian stenosis are described, including the different operative strategies that can be adopted in more challenging cases. This is the first case series describing these four management options.

Presentation

Case 1: A seventy-one year-old female presented with acute on chronic ischaemia of her left arm following a fall and developed dry gangrene of her left thumb. This was initially managed with a heparin infusion followed by stenting of the subclavian artery which relieved her symptoms. Case 2: A fifty-nine year-old male presented with chronic ischemia of the left arm secondary to an occlusion of the left subclavian artery. This was managed by transposition of the left subclavian artery onto the left common carotid artery. Case 3: A sixty-four year-old female presented with left subclavian steal syndrome secondary to subclavian artery stenosis. She underwent carotid subclavian artery bypass. Case 4: A fifty-six year-old female presented with acute left upper limb ischaemia secondary to acutely thrombosed subclavian artery on a CT-angiography. She underwent a carotid to axillary bypass.

Discussion and conclusion

This case series demonstrates the treatment options available to vascular surgeons when managing symptomatic subclavian artery disease. Symptomatic subclavian artery occlusive disease should be treated with endovascular stenting and angioplasty as first line management. If it is not successful then open surgery should be considered. Bypassing the carotid to the subclavian or to the axillary artery are both good treatment modalities.

Lack of flow on time-of-flight MR angiography does not always indicate occlusion

A patient presented acutely with symptoms of cerebellar ischaemia. While non-contrast CT imaging was normal, MRI demonstrated an apparent occlusion of the left vertebral artery on time-of-flight angiography. However, concurrent contrast-enhanced MR angiography (and subsequent CT angiography) demonstrated normal contrast filling of the left vertebral artery. This article discusses the benefits and limitations of time-of-flight angiography for the investigation of possible stroke and highlights a particular technical limitation which could be misinterpreted as an arterial occlusion.

Dialysis arteriovenous fistula causing subclavian steal syndrome in the absence of subclavian artery stenosis

We present a rare cause of subclavian steal syndrome secondary to a dialysis arteriovenous fistula (AVF). A 69-year-old female with end-stage renal disease presented with ataxia and recurrent fainting spells. Angiography revealed normal subclavian arteries bilaterally, a right VA origin occlusion, and an apparent left VA origin occlusion. However, carotid artery angiography demonstrated flow through the posterior communicating artery with retrograde filling of the basilar artery and left VA to its subclavian origin. Repeat left subclavian arteriography during external compression of the AVF demonstrated normal antegrade left VA flow. The AVF was subsequently ligated resulting in complete symptom resolution.

Dealing with symptomatic stenosis of the subclavian artery: Open or endovascular approach? A case report

INTRODUCTION

Stenosis of the subclavian artery is uncommon and it rarely causes symptoms. Only symptomatic patients should be treated.

PRESENTATION OF CASE

We report a case of chronic left upper limb ischemia caused by subclavian artery stenosis after repetitive clavicular fixation. The stenosis was first treated with carotid-subclavian bypass and soon followed by angioplasty and stenting of the subclavian artery because of occlusion of the bypass. Finally, failure of these procedures necessitated a subclavian-axillary crossover bypass.

DISCUSSION

Both extra-anatomic bypass and percutaneous transluminal angioplasty are safe and effective. If feasible, many authors use endovascular treatment. According to literature, extra-anatomic bypass still remains the first choice of treatment for symptomatic patients. However, the introduction of routine stent implantation is equalling these results. Because of its lower long-term patency rate, endovascular treatment is favorable for patients at high risk.

CONCLUSION

Our case is a good example of difficulties involved in choosing the best treatment option for subclavian artery stenosis.

Completely reversed flow in the vertebral artery does not always indicate subclavian steal phenomenon

We evaluated the causes, differential diagnosis and clinical significance of completely reversed flow (CRF) in the vertebral artery (VA). Twenty-three patients diagnosed with CRF in the VA by Doppler ultrasound were studied retrospectively. CRF was divided into intermittent CRF and continuous CRF. The peak reversed velocity (PRV) and ratio of time in intermittent CRF to one cardiac cycle (tICRF/CC) were calculated. Causes of CRF were determined on the basis of previous angiography results. The results indicated that subclavian steal phenomenon (SSP) caused all cases of continuous CRF (n = 8). Intermittent CRF was caused by SSP (n = 6) or proximal VA occlusion (n = 9). PRV and tICRF/CC were increased in SSP as compared with VA occlusion (p < 0.05). Using a cutoff of tICRF/CC = 0.30, we achieved excellent accuracy in predicting the cause of intermittent CRF (100%) and posterior circulatory infarction (91%). Thus, analysis of CRF patterns and measurements of VA parameters can be used in differential diagnosis of the causes of CRF and in prediction of posterior circulatory infarction.

Ischemic posterior circulation stroke: a review of anatomy, clinical presentations, diagnosis, and current management

Posterior circulation strokes represent approximately 20% of all ischemic strokes (1, 2). In contrast to the anterior circulation, several differences in presenting symptoms, clinical evaluation, diagnostic testing, and management strategy exist presenting a challenge to the treating physician. This review will discuss the anatomical, etiological, and clinical classification of PC strokes, identify diagnostic pitfalls, and overview current therapeutic regimens.

Stent Placement for Severe Stenosis of the Left Common Carotid Artery with Internal-to-External Carotid Steal

We report the case of a 64-year-old male with internal carotid artery (ICA)-to-external carotid artery (ECA) steal due to severe stenosis of the common carotid artery (CCA). Left CCA occlusion was initially diagnosed on 3-dimensional time-of-flight magnetic resonance angiography, but digital subtraction angiography revealed severe stenosis of the left CCA and retrograde flow through the left ICA feeding the left ECA. Diverted blood flow from ECA to ICA in cases with occlusion or severe stenosis of the CCA represents a well-known alternative collateral flow pattern called ECA-to-ICA steal. However, collateral flow from ICA to ECA is rarely observed and may be termed ICA-to-ECA steal. We treated CCA stenosis in our patient by carotid artery stenting (CAS) because his CCA stenosis had been gradually progressing since the initial ischaemic attack. Antegrade ICA flow subsequently recovered. To the best of our knowledge, this is the first report of ICA-to-ECA steal normalised by the treatment of CCA stenosis using CAS. i 2014 S. Karger AG, Basel

Bidirectional flow in the vertebral artery is not always indicative of the subclavian steal phenomenon

OBJECTIVE

To evaluate the causes of bidirectional flow in the vertebral artery detected by Doppler sonography and its differential diagnosis.

METHODS

Twenty-nine patients with bidirectional flow in the vertebral artery were retrospectively studied. The vertebral artery parameters, including peak antegrade velocity (PAV), peak reversed velocity (PRV), maximum peak velocity (MPV), peak systolic velocity, resistive index (RI), and diameter, were measured. The MPV was defined as the MPV of bidirectional flow regardless of the velocity of antegrade or retrograde flow. To better predict the cause of bidirectional flow, receiver operating characteristic curves were constructed for these parameters, and the best cutoff values were obtained. The cause of bidirectional flow was determined by angiography.

RESULTS

The causes of bidirectional flow were classified as the subclavian steal phenomenon (n = 21) and factors unrelated to the steal phenomenon (n = 8, including a hypoplastic vertebral artery [n = 4] and proximal vertebral artery stenosis and occlusion [n = 4]). Significant differences were observed between the steal phenomenon and non-steal phenomenon groups (P< .05) for MPV, PRV, PAV, target vertebral artery diameter, and contralateral RI. To determine the cause of bidirectional flow, areas under the receiver operating characteristic curves for the different parameters were obtained: 0.929 for MPV, 0.881 for PRV, 0.824 for PAV, 0.753 for target vertebral artery diameter, and 0.845 for contralateral RI. The cutoff value for MPV was 26.1 cm/s, and the accuracy was 93% (27 of 29).

CONCLUSIONS

Bidirectional flow in the vertebral artery is not always indicative of the subclavian steal phenomenon. Measurement of hemodynamic parameters in the vertebral artery, such as MPV, can facilitate determination of the cause of bidirectional flow.

Brain response characteristics associated with subclavian steal phenomenon

BACKGROUND

Chronic, repetitive, and sublethal hypoperfusion by intra- or extracranial artery stenosis promotes collateral development and conditions the brain toward preventing subsequent lethal ischemia, although these latent properties have rarely been demonstrated in the clinical setting. This study assessed the previously unexplored role of subclavian steal syndrome (SSS) on inciting and protecting brain damage.

METHODS

We enrolled patients diagnosed with SSS associated with subclavian artery stenosis. Subclavian steal was determined by transcranial Doppler and/or digital subtraction angiography. We analyzed the prevalences and predictors of posterior ischemic symptoms and infarcts in SSS patients and also investigated individual cases to demonstrate a clinical evidence of brain conditioning, focusing on cytotoxic and vasogenic edema.

RESULTS

Of 54 SSS patients, 36 (66.7%) had been asymptomatic and incidentally diagnosed with SSS, whereas 18 (33.3%) patients had presented with posterior ischemic symptoms. Symptoms and infarcts including old silent lesions occurred more frequently as unstable hemodynamics of the anterior circulation were combined. Of 18 symptomatic patients, 13 patients (72.2%) had transient ischemic attack and 5 (27.8%) patients had an infarct in the posterior circulation territory. Four patients with cytotoxic edema had mild neurologic deficits and rapid and complete recovery, whereas 1 patient had prolonged, severe vasogenic edema after acute hypertension.

CONCLUSIONS

Although we noted low rates of disabling or fatal strokes in patients with SSS, a variety of vascular and neural factors beyond severity of subclavian steal could influence the likelihood of brain damage.

Vestibulopathy after a modified Blalock-Taussig procedure in a cyanotic congenital heart disease patient

Vestibulopathy is a condition characterized by the onset of vertigo, nausea and vomiting, in the absence of hearing loss or tinnitus. The differential diagnosis includes peripheral otologic disorders and central disorders such as vascular insufficiency. Modified Blalock-Taussig (B-T) shunt, a polytetrafluoroethylene graft from the subclavian artery to the pulmonary artery, has become the palliative procedure of choice in cyanotic congenital heart disease patients. This palliative surgery creates a similar vascular haemodynamic to that seen in the subclavian steal syndrome and when associated with aplasia, hypoplasia or stenosis of the contralateral carotid, vertebral or posterior communicating arteries it may predispose to vascular hypoperfusion and peripheral hypofunctioning of the vestibular system. We report the case of a cyanotic congenital heart disease patient with vertigo and dizziness who underwent a modified B-T fistula on childhood and developed, many years later, a vertiginous syndrome probably of vascular origin.

A forgotten vascular disease with important clinical implications. Subclavian steal syndrome

BACKGROUND

Subclavian Steal Syndrome (SSS) is a fascinating vascular phenomenon in which a steno-occlusive lesion of the proximal subclavian artery causes retrograde flow in the vertebral artery away from the brain stem subsequently causing vertebrobasilar insufficiency. SSS can present with a myriad of neurological and vascular signs and symptoms, but most commonly this phenomenon presents as an incidental finding in an asymptomatic patient.

CASE REPORT

Our patient is a 73-year-old female sent to the cardiology clinic for surgical clearance in preparation for an elective cholecystectomy. Shortness of breath was her only complaint. Review of systems was remarkable for left arm pain and blurry vision with repetitive movement. Physical examination noticeable for absence of left radial pulse. Percutaneous angiography demonstrated a totally occulted left subclavian artery with collateral circulation form the vertebrobasilar apparatus.

CONCLUSIONS

Atypical presentation of this unique entity represents a challenge for physicians who require a high index of suspicion to make the diagnosis. We present an atypical case with radiographical evidence of the steal syndrome, followed by an extensive literature review of the most current diagnostic methods as well as latest recommendations for treatment options and secondary prevention.

Subclavian steal syndrome presenting as recurrent pulmonary oedema associated with acute left ventricular diastolic dysfunction

Subclavian steal syndrome typically presents as angina in patients with internal mammary artery grafts. Atypical clinical presentations have been rarely described. We report an unusual case of subclavian steal syndrome presenting as pulmonary oedema with acute left ventricular diastolic dysfunction and preserved ejection fraction in a patient with internal mammary artery graft and severe stenosis of the proximal left subclavian artery. After successful angioplasty and stenting of subclavian artery, the patient remained asymptomatic for six months, but then experienced acute diastolic dysfunction and recurrent pulmonary oedema associated with critical subclavian in-stent restenosis with stent deformation. This report points out that, in patients with internal mammary-to-LAD grafts, subclavian steal syndrome may present as acute left ventricular diastolic dysfunction and pulmonary oedema even in the presence of normal ejection fraction.

Endovascular stenting for atherosclerotic subclavian artery stenosis in patients with other craniocervical artery stenosis

Atherosclerotic subclavian artery stenosis (SAS) accompanied with other craniocervical artery stenosis (OCAS) is not uncommon in practice. We sought to investigate the safety and efficacy of endovascular stenting for SAS in patients with OCAS. Between January 2004 and February 2012, 71 consecutive atherosclerotic SAS patients who underwent primary stenting in our medical center were included. The enrolled patients were divided into combined-SAS group (n = 51) and solitary-SAS group (n = 20) depending on the presence or absence of OCAS. Data of demographics, procedure, and the followed-up were retrieved and analyzed. The technical success rate was 95.8%; the clinical success rate was 90.1%. There was no catheter-related major stroke or death. The immediate outcomes had no statistical difference between groups. During a mean of 27 ± 20 months (range 2-88 months) followed-up, 7 (10.3%) restenosis and 12 (17.6%) clinical events were identified. The primary patency rate was 95.3, 84.9 and 84.9% at 12, 24 months, and final followed-up respectively, which had no statistical difference between groups (odds ratio (OR), 2.60; 95% confidence interval (CI), 0.54-12.53; P = 0.232). The overall clinical event-free survival rate was 93.5, 86.2 and 54.6%, respectively, where the result of combined-SAS group was inferior to that of the solitary-SAS group (OR, 3.34; 95% CI, 1.02-11.00; P = 0.047). Endovascular stenting was safe and feasible for atherosclerotic SAS in patients with OCAS, although the combined OCAS may have a significant influence on the long-term outcome. Further studies are warrant to investigate the effects of revascularization for multiple craniocervical artery stenoses on the cerebral hemodynamics and long-term outcomes.

A review of subclavian steal syndrome with clinical correlation

Subclavian 'steal' phenomenon is a function of the proximal subclavian artery (SA) steno-occlusive disease, with subsequent retrograde blood flow in the ipsilateral vertebral artery (VA). The symptoms from the compromised vertebrobasilar and brachial blood flows constitute the subclavian steal syndrome (SSS), and include paroxysmal vertigo, drop attacks and/or arm claudication. Once thought to be rare, the emergence of new imaging techniques has drastically improved its diagnosis and prevalence. The syndrome, however, remains characteristically asymptomatic and solely poses no serious danger to the brain. Recent studies have shown a linear correlation between increasing arm blood pressure difference with the occurrence of symptoms. Atherosclerosis of the SA remains the most common cause. Doppler ultrasound is a useful screening tool, but the diagnosis must be confirmed by CT or MR angiography. Conservative treatment is the initial best therapy for this syndrome, with surgery reserved for refractory symptomatic cases. Percutaneous angioplasty and stenting, rather than bypass grafts of the subclavian artery, is the widely favored surgical approach. Nevertheless, large, prospective, randomized, controlled trials are needed to compare the long-term patency rates between the endovascular and open surgical techniques.