A review of subclavian steal syndrome with clinical correlation

Subclavian steal syndrome without subclavian stenosis

Subclavian steal syndrome (SSS) has been well described in the setting of subclavian stenosis. We describe an unusual case of SSS caused by a high-flow arteriovenous dialysis fistula in the absence of subclavian stenosis, provide a review of the literature, and propose that arteriovenous fistula-induced SSS is an underdiagnosed cause of syncope in this population of patients.

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.

Non-ST Elevation Myocardial Infarction Triggered by Subclavian Steal Syndrome

Coronary-subclavian artery (SCA) steal syndrome is an uncommon phenomenon in which coronary flow is diverted into the SCA through the patent left internal mammary artery (LIMA) conduit due to critical subclavian stenosis. The prevalence of significant left SCA (LSCA) stenosis in patients, referred for coronary bypass surgery, has been reported to be 0.2 to 6.8%. Most patients usually present with angina pectoris, and secondary myocardial infarction is rarely reported. Herein, we present a case of coronary bypass graft in which a left anterior descending artery-LIMA graft was applied to supply the left arm due to complete LSCA occlusion. The patient was hospitalized with a diagnosis of non-ST elevation myocardial infarction.

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.

Subclavian steal: Endovascular treatment of total occlusions of the subclavian artery using a retrograde transradial subintimal approach

INTRODUCTION

In symptomatic subclavian steal syndrome, endovascular treatment is the first line of therapy prior to extra-anatomic surgical bypass procedures. Subintimal recanalization has been well described in the literature for the coronary arteries, and more recently, in the lower extremities. By modifying this approach, we present a unique retrograde technique using a heavy tip microwire to perform controlled subintimal dissection.

METHODS

We present two cases of symptomatic subclavian steal related to chronic total occlusion of the left subclavian artery and right innominate artery, respectively. Standard crossing techniques were unsuccessful. Commonly at this point, the procedures would be aborted and open surgical intervention would have to be pursued. In our cases, retrograde access was easily achieved via an ipsilateral retrograde radial artery, using controlled subintimal dissection and a heavy-tipped wire.

RESULTS

We were able to easily achieve recanalization in both attempted cases of chronic total occlusion of the subclavian and innominate artery, using a retrograde radial subintimal approach. Subsequent stent-supported angioplasty resulted in complete revascularization. No major complications were encountered during the procedures; however, one patient did develop thromboembolic stroke secondary to platelet aggregation to the stent graft, 9 days post-procedure.

CONCLUSIONS

Endovascular treatment is considered the first-line intervention in medically refractory patients with symptomatic subclavian steal syndrome. In the setting of chronic total occlusions, a retrograde radial subintimal approach using a heavy tip wire for controlled subintimal dissection is a novel technique that may be considered when standard approaches and wires have failed.

Diagnostic Performance of Combined Contrast-Enhanced Magnetic Resonance Angiography and Phase-Contrast Magnetic Resonance Imaging in Suspected Subclavian Steal Syndrome

PURPOSE

The study sought to evaluate the efficacy of magnetic resonance imaging (MRI) in patients with suspected subclavian steal syndrome (SSS) using both contrast-enhanced (CE) MR angiography and phase-contrast (PC) MRI.

METHODS

Fifteen suspected SSSs from 13 patients were evaluated using CE-MR angiography and PC-MRI. Ten patients also received dynamic CE-MR angiography.

RESULTS

All MRI examinations were technically successful. By combining CE-MR angiography with PC-MRI, 10 SSSs were diagnosed in 9 patients. The delay enhancement dynamic technique predicted SSS with a sensitivity, specificity, and accuracy of 57.1%, 100%, and 72.7%, respectively. Without the dynamic technique, affected delay-enhanced arteries were poorly visualized and could be mistaken for occluded vessels. Retrograde vertebral flow by PC-MRI was used to predict ipsilateral SSS with a sensitivity, specificity, and accuracy of 100%, 60%, and 86.7%, respectively. There were 2 false positives including 1 patient with a proximal total occlusion of the affected vertebral artery and another with brachiocephalic steal syndrome rather than SSS. This suggested that retrograde vertebral flow does not always indicate SSS.

CONCLUSIONS

CE-MR angiography combined with PC-MRI is efficacious when evaluating SSS in clinical practice.

The Role of the Craniocervical Junction in Craniospinal Hydrodynamics and Neurodegenerative Conditions

The craniocervical junction (CCJ) is a potential choke point for craniospinal hydrodynamics and may play a causative or contributory role in the pathogenesis and progression of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, MS, and ALS, as well as many other neurological conditions including hydrocephalus, idiopathic intracranial hypertension, migraines, seizures, silent-strokes, affective disorders, schizophrenia, and psychosis. The purpose of this paper is to provide an overview of the critical role of the CCJ in craniospinal hydrodynamics and to stimulate further research that may lead to new approaches for the prevention and treatment of the above neurodegenerative and neurological conditions.

Pseudo subclavian steal syndrome: Case report

INTRODUCTION

Vertebrobasilar insufficiency (VBI) is a condition that results from restricted blood flow to the posterior portions of the brain, which are primarily served by the vertebral and basilar arteries. It is the most common cause of vertigo in the elderly and is usually accompanied by impaired vision and sensation. Congenital abnormalities, atherosclerosis, stroke and/or trauma may all lead to decreased vertebrobasilar circulation. A syndrome called Subclavian Steal Syndrome (SSS), which manifests with similar neurological symptoms but with a different pathophysiology, may also cause VBI.

CASE PRESENTATION

A middle-aged female presented with gradual onset fainting and vertigo attacks. Cardiac, auditory and autonomic etiologies were investigated and excluded. Clinical findings and presentation were highly suggestive of subclavian steal. However, subsequent CT angiography showed normal subclavian arteries. Instead, findings included a persistent right trigeminal artery (PTA), stenosis of the right proximal internal carotid artery, atresis of the left vertebral artery and distal segment of right vertebral artery, congenitally compromised changes in vertebral circulation (bilateral absence of the posterior communicating arteries (PCOMs)) and an absent anterograde vertebrobasilar circulation. Symptoms resolved after carotid endarterectomy.

DISCUSSION

Due to the absence of a normally developed posterior circulation, the PTA was the main source of blood supply for the patient. Development of recent artheromatous changes in the right internal carotid artery, however, resulted in decreased blood through PTA, further compromising posterior circulation. This resulted in vertebrobasilar insufficiency, and manifested in symptomology similar to SSS.

CONCLUSIONS

This clinical encounter illustrates the relative contribution of anatomical and vasoocclusive factors in closely mimicking symptoms of subclavian steal syndrome.

Waveform patterns and peak reversed velocity in vertebral arteries predict severe subclavian artery stenosis and occlusion

This study investigated the value of analyzing spectral Doppler waveform patterns and measuring the peak reversed velocity (PRV) of the vertebral artery (VA) in predicting proximal severe subclavian artery (SA) stenosis and occlusion. Fifty-one patients with proximal SA stenosis were studied retrospectively. Based on the depth of the mid-systolic notch, the Doppler waveforms of the ipsilateral VA were divided into five subtypes (type I, n = 8; type II, n = 8; type III, n = 6; type IV, n = 13; and type V, n = 16). PRV was also measured. PRV receiver operating characteristic curves were constructed to obtain the best cutoff value for predicting severe SA stenosis or complete SA occlusion. The results indicated that both VA Doppler waveform and PRV were associated with the degree of SA stenosis (p < 0.05). PRV and the Doppler waveform in the VA had similar accuracy in predicting SA occlusion (84.3%, 43/51). PRV was more accurate than VA waveforms in predicting severe SA stenosis (98%, 50/51 vs. 94.1%, 48/51). However, no significant differences between the two methods in predicting severe SA stenosis were observed (p = 0.84). Thus, with severe obstruction of the SA, typical Doppler waveform patterns of the VA could be observed. PRV is a helpful criterion in predicting severe stenosis and occlusion of the SA.

Syncope: epidemiology, etiology, and prognosis

Syncope is a common medical problem, with a frequency between 15% and 39%. In the general population, the annual number episodes are 18.1–39.7 per 1000 patients, with similar incidence between genders. The first report of the incidence of syncope is 6.2 per 1000 person-years. However, there is a significant increase in the incidence of syncope after 70 years of age with rate annual 19.5 per thousand individuals after 80 years. It presents a recurrence rate of 35% and 29% of physical injury. Among the causes of syncope, the mediated neural reflex, known as neurocardiogenic or vasovagal syncope, is the most frequent. The others are of cardiac origin, orthostatic hypotension, carotid sinus hypersensitivity, neurological and endocrinological causes and psychiatric disorders. The diagnosis of syncope can be made by clinical method associated with the electrocardiogram in up 50% of patients. Its prognosis is determined by the underlying etiology specifically the presence and severity of cardiac disease. The annual mortality can reach between 18 and 33% if cardiac cause, and between 0 and 12% if the non-cardiac cause. Thus, it is imperative to identify its cause and risk stratification for positive impact in reducing morbidity and mortality.

SPARKLE (Subtypes of Ischaemic Stroke Classification System), incorporating measurement of carotid plaque burden: a new validated tool for the classification of ischemic stroke subtypes

BACKGROUND

Previous classification systems of acute ischemic stroke (Causative Classification System, CCS, of acute ischemic stroke, Trial of Org 10172 in Acute Stroke Treatment, TOAST) established the diagnosis of large artery disease (LAD) based on the presence or absence of carotid stenosis. However, carotid plaque burden is a stronger predictor of cardiovascular risk than stenosis. Our objective was to update definitions of ischemic stroke subtypes to improve the detection of LAD and to assess the validity and reliability of a new classification system: SPARKLE (Subtypes of Ischaemic Stroke Classification System).

METHODS

In a retrospective review of clinical research data, we compared three stroke subtype classifications: CCS, TOAST and SPARKLE. We analyzed a random sample of 275 patients presenting with minor stroke or transient ischemic attack (TIA) in an Urgent TIA Clinic in London, Ont., Canada, between 2002 and 2012.

RESULTS

There was substantial overall agreement between SPARKLE and CCS (κ = 0.75), with significant differences in the rate of detection of LAD, cardioembolic and undetermined causes of stroke or TIA. The inter-rater reliability of SPARKLE was substantial (κ = 0.76) and the intra-rater reliability was excellent (κ = 0.91).

CONCLUSION

SPARKLE is a valid and reliable classification system, providing advantages compared to CCS and TOAST. The incorporation of plaque burden into the classification of LAD increases the proportion of cases attributable to LAD and reduces the proportion classified as being of 'undetermined' etiology.

An aberrant subclavian artery exhibiting the partial steal phenomenon in a patient with VACTERL association

We herein report the case of a 22-year-old Caucasian man with known vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, cardiac defects, renal and limb anomalies (VACTERL) association who presented with a headache and vertigo following the sudden and temporary loss of consciousness while attending a concert four days before admission to the hospital. On a physical examination, the following findings were found: a low body height, low-set ears, thoracic scoliosis and a mild holosystolic heart murmur. A neurosonological examination revealed a partial subclavian steal phenomenon. CT angiography of the neck vessels and aortic arch confirmed an anomalous right subclavian artery -known as the lusorian artery. Further studies are warranted in patients with VACTERL in order to identify possible links between the prevalence of an aberrant right subclavian artery (lusorian artery) and possible congenital subclavian steal syndrome or dysphagia lusoria. In addition, duplex ultrasound of the carotid and vertebral arteries may be performed as part of screening examinations in patients with congenital syndromes.

A case of cerebellar infarction caused by acute subclavian thrombus following minor trauma

Subclavian steal syndrome caused by an acute thrombus is very rare. We present a case of cerebellar infarction with proximal subclavian artery thrombosis. A 56-year-old woman was admitted for sudden vertigo. One day prior to admission, she received a shoulder massage comprised of chiropractic manipulation. On examination, her left hand was pale and radial pulses were absent. Blood pressure was weak in the left arm. Downbeat nystagmus and a right falling tendency were observed. Brain MRI showed multiple acute infarctions in the left cerebellum. The findings of Doppler ultrasonography in the left vertebral artery were compatible with a partial subclavian artery steal phenomenon. Digital subtraction angiography demonstrated a large thrombus in the left subclavian artery. After heparin infusion, thrombus size markedly decreased. Cerebellar infarction caused by acute subclavian thrombosis following minor trauma is rare, but the thrombus can be successfully resolved with anticoagulation.

Bilateral subclavian steal syndrome with vertigo

Subclavian steal syndrome (SSS) is usually caused by unilateral subclavian artery (SA) occlusion, and bilateral SSS is very rare. Takayasu's arteritis (TA) is a chronic granulomatous form of vasculitis that affects the SA, most commonly in women aged 15-40 years. We report a rare case of bilateral SSS due to TA in a 52-year-old woman, who exhibited severe vertigo. Although her blood pressure was within the normal range and did not differ between her arms, Doppler ultrasonography revealed low antegrade blood flow in the right SA and retrograde flow in the left SA. Computed tomography angiography demonstrated complete obstruction of the bilateral SA proximal to the vertebral artery origin. The more marked decrease in the blood flow of the vertebrobasilar artery experienced in bilateral SSS compared with unilateral SSS is considered to have caused the severe rotatory vertigo in the present patient. Since the vascular conditions of TA progressively deteriorate, delayed diagnosis and treatment could result in poor outcomes and unfavorable prognosis. We suggest that SSS with TA might require an early detection and treatment as well as careful follow-up for preventing vertigo and other neurological deficits in the vertebrobasilar arterial region.