Prevalence and impact of the subclavian steal syndrome

Late Neuro Events in Asymptomatic versus Symptomatic Isolated Subclavian Steal

BACKGROUND

Natural history of subclavian steal (SS) is not well defined. This is the largest study to date, to analyze late neuro events of patients with asymptomatic (asx) vs symptomatic (sx) isolated SS in over 5-year period.

PATIENT POPULATION/METHODS

SS detected during 11,762 routine carotid duplex ultrasound exams (CDUE) done over a 2-year period were analyzed. Late neuro events including TIA/stroke (hemispheric anterior cerebral vs posterior stroke) were recorded for isolated SS (no associated carotid disease). Kaplan Myer analysis for freedom from stroke for isolated sx (posterior circulation symptom/arm claudication) and isolated asx SS patients and for patients with combined SS and carotid disease was done.

RESULT

285 SS were detected during 11,762 CDUE, 191 had retrograde vertebral flow (complete steal) and 94 had bidirectional flow (partial steal), 64% on left and 33% on right. Indications of CDU testing included: post CEA/CAS surveillance 27%, surveillance of carotid stenosis 45%, asx carotid screening/bruit 8%, hemispheric neuro symptoms 9%, arm claudication/posterior circulation symptoms 12%. 115 (40%) had isolated SS and 60% were associated with >70% carotid stenosis. The mean systolic arm pressure differential was 32.4mmHg in the whole series and was 31.8 vs 34.4 for asx vs sx patients, (p=0.537). Mean systolic pressure for patient with retrograde flow was 105mmHg vs 129mmHg for bidirectional flow and 126.8 for normal antegrade flow (p < 0.0001). 51 interventions were done for sx patients: 27 subclavian PTA/Stent, 5 carotid subclavian bypasses, (for claudication/posterior circulation symptoms), and 19 CEA for associated carotid disease. At a mean follow-up of 34 months (range of 1-79 months), 10 late strokes were noted in the whole group, however in 115 patients with isolated SS (85 were initially asx and 30 sx), there was 1 TIA and 2 late strokes in asx SS group, both were not posterior strokes (1 lacunar hypertensive stroke and 1 cardiac emboli) and no strokes in sx SS group. Kaplan Myer analysis (including patients with carotid artery disease) showed the rates of freedom from stroke at 1, 3, and 5 years, were 99%, 97%, and 97% for the whole series (Figure 1). The rates of freedom from stroke in the isolated SS group at 1, 3, and 5 years were 100%, 97%, and 97% in the whole series, for patients with no symptoms (posterior circulation or arm claudication) were 100%, 96%, and 96%, and for patients with posterior circulation symptoms and/or claudication were 100%, 100%, and 100% respectively. (Figure 2) CONCLUSION: Subclavian steal in patients undergoing CDUE is rare (2%), the majority of which were asymptomatic. Isolated subclavian steal had relatively benign course with no posterior circulation strokes up to 5 years.

Early Detection and One-Year Follow-Up of Subclavian Steal Syndrome Treated With Traditional Chinese Medicine: A Case Report

Subclavian steal syndrome (SSS) often goes undiagnosed because of its variable and subtle symptoms, highlighting the need for innovative diagnostic approaches. This case report explores the integration of traditional Chinese medicine (TCM) in both diagnosing and managing SSS, marking a pioneering contribution to the field. An 80-year-old woman with persistent dizziness, unresponsive to conventional treatments, underwent TCM pulse diagnosis, which revealed significant inter-arm pulse discrepancies. Subsequent Western imaging confirmed SSS. The patient was treated with Chinese herbal medicines (CHMs) targeting Qi deficiency and blood stasis, resulting in significant symptom improvement and a reduction in inter-arm systolic blood pressure disparities. Follow-up over 1 year showed sustained benefits. The integration of TCM pulse diagnosis, CHMs, and Western imaging highlights their complementary roles and potential as adjunctive therapies for managing SSS, offering a novel and comprehensive therapeutic strategy.

Frequency of subclavian steal syndrome in a sample of non-Western population

BACKGROUND

Subclavian steal syndrome (SSS) is not rarely found during ultrasound examinations. Previous reports demonstrated a relation between ethnic factors and SSS. Data regarding SSS in non-Western population are still lacking. We aimed to investigate the frequency of SSS in a sample of Egyptian population.

METHODS

In a single-center observational study, we conducted a retrospective analysis of successive patients with competent ultrasound examinations of the brain supplying vessels. The patients presented to our neurovascular laboratory in the context of routine clinical practice.

RESULTS

We enrolled 514 patients in our study. SSS was detected in 9 patients (1.8 %) with a median (IQR) age of 58 (56-63) years. One patient with second-degree SSS received a subclavian stent. Among patients with SSS, 4 patients (44.4 %) had carotid atherosclerosis, 4 patients (44.4 %) had ischemic vascular events in the posterior circulation, and two (22.2 %) had hemodynamically significant carotid stenosis ≥50 %. Using a ROC curve, an interarm SBP (systolic blood pressure) difference of ≥10 mmHg had a sensitivity of 77.8 % and specificity of 66 %, whereas a difference of ≥20 mmHg was associated with a sensitivity of 55.6 % and specificity of 92.4 % for SSS (AUC 0.79, 95 % CI 0.6-0.97, p = 0.004).

CONCLUSIONS

SSS is not rare among Egyptian population and should be in mind during ultrasound examination, especially for patient with ischemic events in the posterior circulation and those with significant interarm SBP difference.

Surgical outcomes of subclavian steal syndrome combined with carotid artery stenosis: A single-center retrospective observational study

OBJECTIVE

To explore the prevalence and risk factors of carotid artery (CA) stenosis among subclavian steal syndrome (SSS) patients and to record their prognoses.

METHODS

This observational study was retrospective. From January 2015 to October 2022, 169 patients were diagnosed with SSS. Among them, 51 combined with CA stenosis have surgical indications for both diseases. In this cohort, 24 were treated for subclavian artery (23 endovascular, 1 open), 12 for CA (6 endovascular, 6 open), and 5 for both (1 endovascular, 1 open, 3 hybrid). The primary end point was mortality, and the secondary end points were vessel re-stenosis and other complications. Patients were followed up through outpatient, online, or telephone.

RESULTS

Compared with simple SSS, patients who suffered from both were older (60.51 ± 9.304 versus 66.69 ± 7.921, P < 0.001) and more males (57.6% versus 86.3%, P < .001). Besides, they presented a higher prevalence of hyperhomocysteinemia (P = .015), diabetes mellitus (P = .036), and CVA/TIA (P = .036). No patient died within 30 days after surgery; four complications occurred (1 stroke, 1 hearing loss, 1 TIA, 1 infection). During a median follow-up of 37.6 months, two patients died without relation to the operation, three appeared in-stent restenosis, and one developed contrast nephropathy.

DISCUSSION

This study observed and analyzed different intervention methods and their prognosis in SSS combined with CA stenosis patients, and due to the limited number of participants, more data support would be needed.

CONCLUSIONS

The management of SSS patients combined with CA stenosis is more challenging compared to simple SSS. Our research demonstrated different surgical methods and their prognosis.

A case of concomitant subclavian steal syndrome and thoracic outlet syndrome

A 59-year-old woman presented with dizziness and numbness of her left upper limb. Computed tomography (CT) angiography revealed an occlusion of the subclavian artery at its origin, leading to a diagnosis of subclavian steal syndrome. She was treated with percutaneous angioplasty and stenting; however, her symptoms did not improve. CT angiography of the arm in the elevated position revealed subclavian artery stenosis at the costoclavicular space, and the diagnosis was neurogenic thoracic outlet syndrome (TOS). First-rib resection was performed, and the symptoms disappeared immediately after surgery. TOS should be considered when symptoms persist despite subclavian steal syndrome treatment. Physical examination and CT imaging with the arm elevated aid in diagnosing TOS.

Relationship Between Subclavian Artery Stenosis Lesions and Posterior Circulation Infarction: A Preliminary Study

BACKGROUND

To investigate the correlation between subclavian steal syndrome and posterior circulation infarction using magnetic resonance imaging.

METHODS

A total of 294 patients diagnosed with subclavian steal syndrome using carotid Doppler ultrasonography were retrospectively included. According to the magnetic resonance imaging results, they were divided into posterior circulation infarction group and nonposterior circulation infarction group. Clinical indicators and carotid Doppler ultrasound parameters of patients were collected, and they were screened to establish a multiple logistic regression model. Receiver operating characteristic curve analysis of the established multiple logistic regression model was performed, and the area under the curve was calculated to evaluate the predictive efficiency of the model.

RESULTS

After statistical analysis of all parameters of the 2 groups of patients, a total of 10 parameters were included in multiple logistic regression to establish a model. The results showed a correlation between posterior circulation infarction and subclavian artery occlusion, grade III subclavian steal syndrome, gender, vulnerable plaques, National Institutes of Health Stroke Scale score, and age. After the receiver operating characteristic curve analysis of the model, the area under the curve for the multiple logistic regression model was 0.773.

CONCLUSIONS

The multiparameter composite model based on clinical baseline data and carotid Doppler ultrasonography parameters can effectively predict posterior circulation infarction and offer novel insight for clinical diagnosis.

Effects of percutaneous endovascular angioplasty for severe stenosis or occlusion of subclavian artery

To investigate the effect and safety of percutaneous endovascular angioplasty (PEA) with optional stenting for the treatment of severe stenosis or occlusion of subclavian artery, patients with severe stenosis ≥ 70% or occlusion of subclavian artery treated with PEA were retrospectively enrolled. The clinical data were analyzed. A total of 222 patients were retrospectively enrolled, including 151 males (68.0%) and 71 females (32.0%) aged 48-86 (mean 63.9 ± 9.0) years. Forty-seven (21.2%) patients had comorbidities. Subclavian artery stenosis ≥ 70% was present in 201 (90.5%) patients and complete subclavian occlusion in 21 (9.5%) cases. Angioplasty was successfully performed in all (100%) patients. Balloon-expandable stents were used in 190 (85.6%) cases, and self-expandable stents in 20 (9.0%) cases. Only 12 (5.4%) cases were treated with balloon dilation only. Among 210 patients treated with stent angioplasty, 71 (33.8% or 71/210) cases underwent balloon pre-dilation, 139 (66.2% or 139/210) had direct deployment of balloon-expandable stents, and 2 (1.0% or 2/210) experienced balloon post-dilation. Distal embolization protection devices were used in 5 (2.3% or 5/222) cases. Periprocedural complications occurred in 3 (1.4%) patients, including aortic dissection in 2 (0.9%) cases and right middle cerebral artery embolism in 1 (0.5%). No hemorrhage occurred. Among 182 (82.0%) patients with 6-month follow-up, restenosis > 70% occurred in 1 (0.5%) patient, and among 68 (30.6%) patients with 12-month follow-up, restenosis > 70% took place in 11 (16.2%) patients. Percutaneous endovascular angioplasty can be safely and efficiently performed for the treatment of severe stenosis ≥ 70% or occlusion of subclavian artery.

A Novel Case of Anomalous Origin of Left Vertebral Artery Associated With Left Subclavian Steal Syndrome

The subclavian steal syndrome (SSS) is defined by the reversal of flow in the ipsilateral vertebral artery in the setting of subclavian artery stenosis proximal to its origin. Here, we describe a rare case of left SSS with significant left subclavian artery stenosis associated with anomalous origin of the left vertebral artery (LVA) directly from the aortic arch in a patient presenting with signs of vertebrobasilar insufficiency and resolution of symptoms following angioplasty. Through this case, the authors try to emphasize the importance and the correct technique of using Doppler ultrasonography, and the importance of invasive angiography in understanding the mechanism of subclavian steal in patients with anomalous LVA origin.

Atypical presentation of subclavian steal syndrome with left sided sensorineural deafness

We present a rare manifestation of a common pathology: left sided sensorineural hearing loss secondary to subclavian steal syndrome after thoracic endovascular aortic repair for complicated acute aortic dissection. We describe the vascular physiology that can result in unilateral hearing loss and provide a brief review of subclavian steal syndrome. This case report highlights the importance of avid clinical recognition of an atypical presentation of a common vascular disease.

A rare association of subclavian steal syndrome with bilateral carotid artery stenosis: a case report

Bilateral carotid artery stenosis in the context of subclavian steal syndrome is an extremely rare finding. We report the case of a 75-year-old woman who presented with a transient ischemic attack. Bilateral internal carotid stenosis associated with left subclavian steal syndrome was diagnosed. Left internal carotid endarterectomy was performed under locoregional anesthesia. Inflation of a blood pressure cuff reversed the neurologic symptoms that appeared after internal carotid clamping. This rarely reported case remains a challenge to diagnose and treat because of its complex mechanisms and multiple risk factors. Our case highlights the importance of the surgical strategy adopted and the need for a good initial assessment.

Navigating Subclavian Artery Stenosis in Pregnancy: A Multidisciplinary Approach to a High-Risk Case

Given the possibility of serious consequences for both the pregnant woman and the developing baby, subclavian artery stenosis (SAS) during pregnancy represents a unique but demanding scenario that requires quick and thorough treatment. In this report, we present a case of a pregnant patient with SAS who was managed effectively by employing a multidisciplinary approach, with a focus on clinical decision-making and intervention measures to ensure the best possible outcomes for both the mother and the fetus. This case report highlights the significance of prompt recognition and action to avoid the adverse consequences of SAS during pregnancy. To establish uniform standards for managing such high-risk cases and achieve better patient outcomes, more research and case studies are required.

Outcomes of covered stents versus bare-metal stents for subclavian artery occlusive disease

Objective

To compare the clinical efficacy of covered stents and bare-metal stents in the endovascular treatment of subclavian artery occlusive disease.

Methods

Between January 2014 and December 2020, 161 patients (112 males) underwent stenting of left subclavian arteries; CSs were implanted in 55 patients (34.2%) and BMSs in 106 (65.8%). Thirty-day outcomes, mid-term patency, and follow-up results were analyzed with Kaplan-Meier curves. Relevant clinical, anatomical, and procedural factors were evaluated for their association with patency in the two groups using Cox proportional hazards regression.

Results

Mean follow-up was 45 ± 18 months. The primary patency was 93.8% (95% CI, 81.9%-98.0%) in the covered stent group and 73.7% (95% CI, 63.2%-81.6%; P = 0.010) in the bare-metal stent group. The primary patency in the total occlusion subcategory was significant in favor of CS (93.3%, 95% CI, 61.26%-99.0%) compared with BMS (42.3%, 95% CI, 22.9%-60.5%; P = 0.005). Cox proportional hazards regression indicated that the use of BMSs [hazard ratio (HR), 4.90; 95% CI, 1.47-16.31; P = 0.010] and total occlusive lesions (HR, 7.03; 95% CI, 3.02-16.34; P < 0.001) were negative predictors of patency, and the vessel diameter (HR, 3.17; 95% CI, 1.04-9.71; P = 0.043)) was a positive predictor of patency.

Conclusion

Compared with bare stents, covered stents have a higher midterm primary patency in the treatment of subclavian artery occlusive disease.

Variant of subclavian steal syndrome: unusual anatomical relationship between left subclavian artery and left vertebral artery

A woman in her 70s presented to her general practitioner (GP) with a 3-month history of left upper arm pain and weakness. A significant difference in bilateral blood pressures was noted and a further history elicited coolness in her left arm without functional compromise. A CT angiography revealed variant subclavian steal syndrome with a subclavian arterial stenosis, which was proximal to both the internal mammary and thyrocervical trunk and her left vertebral artery originating from the aortic arch. She was referred to a vascular surgeon but declined surgical intervention. Her symptoms remain stable with 6-month follow-up from her GP. This case highlights the importance of considering vascular aetiologies in upper limb pain and weakness. Our case reviews the differential diagnoses of upper limb pain and weakness, consequently leading to the discussion of an interesting variant of subclavian stenosis.

Subtypes of the Completely Reversed Flow Waveform in Vertebral Artery Can Help to Differentiate Subclavian Artery Occlusion from Severe Stenosis

OBJECTIVES

To investigate the value of subtypes of completely reversed flow (CRF) waveform in vertebral artery (VA) on Doppler ultrasound in differentiation occlusion from severe stenosis of the ipsilateral proximal subclavian artery (SA).

METHODS

A total of 357 patients with CRF in the VA on Doppler US were reviewed retrospectively. Among them, 49 patients (mean age, 68.2 ± 7.8 years) confirmed by digital subtraction angiography (DSA) were included. According to the status of diastolic flow, the CRF was divided into continuous CRF (CCRF, n = 27) and intermittent CRF (ICRF, n = 22). The correlation of subtypes of CRF waveform and VA parameters with the severity of SA stenosis was evaluated. The severity of SA stenosis was determined by DSA.

RESULTS

Of those 49 patients, SA occlusion was observed in 33 patients (67%, occlusion group) and severe stenosis in 16 patients (33%, stenosis group). The subtypes of CRF waveforms showed a significant between-group difference (p = 0.005). CCRF exhibited an accuracy of 85.2% (23/27) in diagnosing SA occlusion. The diameter of the target VA with ICRF showed a significant between-group difference (p = 0.041). The target VA diameter ≥ 3.8 mm in ICRF achieved an accuracy of 81.8% (18/22), and its combination with CCRF achieved an accuracy of 83.7% (41/49) in the differentiation of SA occlusion from severe stenosis.

CONCLUSIONS

Subtypes of CRF in VA can help to differentiate SA occlusion from severe stenosis. CCRF has higher accuracy in diagnosing SA occlusion. The CCRF waveform plus VA diameter in ICRF is more accurate for differentiating SA occlusion from severe stenosis.

Computed Tomography Angiography in the Diagnosis of Subclavian-Vertebral Artery Steal

Purpose

Computed tomography angiography (CTA) is commonly used in the diagnosis and evaluation of subclavian steal (SS). However, the abnormal manifestations of vertebral artery (VA) in SS on CTA are vastly under-recognized and prone to misdiagnosis. We reported for the first time the abnormal CTA manifestations of VA in SS, and evaluated the value and pitfalls of CTA in the diagnosis of SS, aiming to avoid misdiagnosis and facilitate correct diagnosis of SS using CTA.

Patients and Methods

This study retrospectively included 19 patients diagnosed with SS using carotid duplex sonography (CDS) and digital subtraction angiography (DSA) between 2018 and 2022 at a tertiary neurology clinic in Chongqing, China. Their CDS, DSA and CTA results were collected and analyzed. The diagnostic consistency between CTA and DSA in grading subclavian artery stenosis was evaluated, and the CTA manifestations of VA were summarized.

Results

All patients presented subclavian steno-occlusion on the affected side, without steno-occlusion of the contralateral subclavian artery or bilateral VA on DSA. A high concordance was observed between CTA and DSA in grading subclavian artery stenosis (Kappa = 0.825, P = 0.000). However, only 26.3% of patients presented normal VA on CTA, whereas 73.7% of patients presented shallow VA ipsilateral to subclavian steno-occlusion. A 28.6% of patients with shallow VA were misdiagnosed as having vertebral arteriopathy. The presence of shallow VA had no significant correlation with age, gender, severity of subclavian artery stenosis, diameter of VA or model of CT scanner (all P>0.05). Although not statistically significant, the incidence of shallow VA increased with higher SS grade.

Conclusion

Carotid CTA is highly accurate for diagnosing subclavian steno-occlusion, whereas shallow VA is the pitfall of CTA in diagnosing SS. It is important to improve the recognition of shallow VA to avoid misdiagnosis.

Are the Variations of the Vascular System in Neurology Underestimated ?

The spinal cord issues affect dogs and cats very commonly. The right diagnostics, therapy, and patient’s managements are challenging for almost all veterinarians. There exist many vascular anomalies such as: the vertebral arteries ectasia, hypoplasia and subclavian steal syndrome. These anomalies affect the patient’s neurological status directly. The modern diagnostic approaches (Computed Tomography [CT], and Magnetic Resonance Imaging [MRI]) help with the diagnosis of the vascular abnormalities of the spinal cord and various other vascular anomalies. The cervical part of the spinal cord is supplied with the spinal branches from the vertebral arteries. The vertebral arteries as the first branches arise separately from the subclavian artery and they exit the thoracic aperture and enter into the transverse foramen of the sixth cervical vertebra. The arterial system of dogs was studied in 14 dogs (carcasses), the average age of which was 7 years. The carcasses were divided into two groups: 11 dogs were studied by the corrosion casting method (Duracryl Plus) and 3 dogs were studied by contrast radiography (Urografin 76 %). We confirmed the standard origin and course of the left vertebral for all but one case. The right vertebral artery originated as an independent branch in 57.14 % of the cases; in the rest of them, we reported on the variability in origin and formation of inconstant branches. The formation of anastomoses was reported also. Our work contributed new information about the thoracic and cervical arterial system in dogs.

Critical Analysis of Vertebral Artery Flow Patterns/Subclavian Steal Detected by Cerebrovascular Duplex Ultrasound Exams and Its Clinical Implications

BACKGROUND

The prevalence of subclavian steal (defined as retrograde/bidirectional vertebral artery flow) in the general population and in patients undergoing cerebrovascular duplex ultrasound (CDUS) exams is variable. This is the largest study to date to analyze the incidence of duplex-suggested subclavian steal in 5615 CDUS exams over a one year period and to examine its clinical implications.

PATIENT POPULATION AND METHODS

All consecutive CDUS exams performed over a one year period were examined for the presence of subclavian steal. Indications of testing, presence of posterior cerebral circulation/subclavian steal symptoms, and any interventions for subclavian steal were analyzed.

RESULTS

171/5,615 (3.1%) were found to have subclavian steal (duplex-suggested). 117 (2.1%) had retrograde flow and 54 (1%) had bidirectional flow. 104/171 (60.8%) were left sided. Indications for CDUS were: post CEA/CAS surveillance in 39 patients (22.8%), surveillance for progression of carotid stenosis in 76 patients (44.4%), TIA/stroke in 26 patients (15%), asymptomatic screening/carotid bruit in 18 patients (10.5%) and isolated posterior cerebral circulation symptoms in 12 patients (7%). 63% of patients had associated >50% carotid stenosis. The mean arm Doppler pressure gradient was 32.2 mmHg for asymptomatic patients vs 37mmHg for patients with posterior circulation symptoms (p=.3254). There were significant differences between the mean systolic arm pressure for patients with retrograde vs antegrade vs bidirectional flow (105 mmHg vs 146 vs 134, p<.0001). All patients with retrograde flow had >50% subclavian stenosis or occlusion (100/117 had subtotal/total occlusion) except for one patient. Meanwhile, 52/54 patients with bidirectional flow had >50% subclavian stenosis (6/54 with subtotal/total occlusion) while two patients were normal/<50% stenosis (p<.0001). Overall, 26/171 patients (15.2%) had interventions for disabling symptoms. 11/26 of all interventions were for disabling arm claudication, and only 10/171 patients (5.8%) were done for disabling posterior circulation symptoms with complete resolution of symptoms in all except one. At a late follow-up with a mean of 18 mos. (range 1-37 mos.), there was no late major stroke with only two lacunar infarcts (not subclavian steal related). There were also seven late deaths, none stroke related.

CONCLUSIONS

The incidence of subclavian steal in patients who undergo CDUS is relatively rare. Most of these patients are asymptomatic and can be treated conservatively with only a few percentage who may need intervention for disabling symptoms with good symptom resolution.

Effects of different bypass surgeries on LSA revascularization in patients with left subclavian occlusion

INTRO

Left subclavian artery bypass surgery is mainly carried out for patients with severe left subclavian occlusion. This paper aimed to evaluate the hemodynamic effects of different surgical bypass modes on left subclavian artery revascularization.

METHODS

Three-dimensional models of the aorta were reconstructed from CTA images of a patient with left subclavian artery occlusion, a patient with type B aortic dissection with left subclavian artery coverage during thoracic endovascular aortic repair, and a healthy 74 year-old man, resulting in six modes for each person: healthy left subclavian artery mode, left subclavian artery occlusion mode and four bypass modes. Hemodynamic parameters, including flow field, flow distribution, pressure gradient, and wall shear stress, were calculated using computational fluid dynamics.

RESULTS

After left subclavian artery bypass surgery, distal left subclavian artery blood flow resulting from left common carotid artery to distal left subclavian artery bypass was 100% of that in the healthy mode, while the other modes yielded flows at least 91%. Moreover, reversed flow only completely disappeared with left common carotid artery to distal left subclavian artery bypass, whereas reverse flow was observed in the other three modes in early systole.

CONCLUSION

Left common carotid artery to distal left subclavian artery bypass can effectively reduce reverse blood flow in the left vertebral artery, and it is a feasible, effective, and safe option for left subclavian artery revascularization in patients with left subclavian occlusion.

Subclavian steal syndrome secondary to atherosclerosis: A case report and review of literature

Subclavian Steal Syndrome (SSS) is a rare vascular syndrome caused due to proximal occlusion or stenosis of subclavian or innominate artery. It is usually asymptomatic but occasionally may present with vertebro‐basilar insufficiency and/or upper limb ischemia. Atherosclerosis is the most common cause.

Dizziness and syncope after subclavian steal: A case report of a rarely symptomatic, common vascular disorder

Subclavian steal syndrome (SSS) is a manifestation of vertebrobasilar artery insufficiency due to stenosis of the proximal subclavian artery. It is a common vascular disorder; however, most patients are asymptomatic, and the disorder is commonly found incidentally during imaging. Nevertheless, some patients may present with arm ischemia or signs and symptoms of vertebrobasilar insufficiency, such as vertigo, dizziness, diplopia, ataxia, dysarthria, and syncopal episodes. We present a case of a male patient who presented with sudden onset dizziness, syncopal episodes, and blood pressure discrepancy between his arms. Diagnosis was a challenge, and the patient underwent several investigations, including basic bloodwork, electrocardiography (ECG), echocardiography, brain computed tomography (CT), and coronary CT angiography (CTA). Narrowing in the proximal left subclavian artery was found during coronary CTA, which confirmed the diagnosis of SSS.

Subclavian Artery Calcification: A Narrative Review

Subclavian artery calcification (SAC) affects 2% of the population and presents a serious risk of developing into subclavian steal syndrome (SSS). Risk factors for plaque formation of the subclavian artery include diabetes, hypertension, and smoking. While SAC generally presents as asymptomatic, symptoms in severe cases may include numbness, pain at rest, and ischemic gangrene. Patients with severe SSS are at high risk of developing neurological symptoms as a result of vertebrobasilar insufficiency affecting posterior cerebral perfusion. On physical examination, SSS is preliminarily diagnosed from bilateral inter-arm systolic blood pressure discrepancy (>10 mmHg), which can be further confirmed with vascular imaging. Duplex ultrasound (DUS) is a cost-effective and non-invasive baseline technique for visualizing luminal stenosis and quantifying peak systolic velocity (PSV). Computed tomography angiography (CTA) provides high-quality, fast, three-dimensional (3D) imaging at the cost of introducing nephrotoxic contrast agents. Magnetic resonance angiography (MRA) is the safest 3D imaging modality, without the use of X-rays and contrast agents, that is useful in assessing plaque characteristics and degree of stenosis. DUS-assisted digital subtraction angiography (DSA) remains the gold standard for grading the degree of stenosis in the subclavian artery and determining the distance between the puncture site and lesion, which can be carried out in a combined procedure with endovascular management strategies. The fundamental treatment options are surgical and endovascular intervention. Endovascular treatment options include percutaneous transluminal angiography (PTA) for recanalization of the stenosed vessel and permanent balloon stenting to prevent collapse after PTA. Overall, the benefits of endovascular management encompass faster recovery, lower stenosis recurrence rate, and lower incidence of complications, making it the treatment of choice in low-risk patients. Surgical interventions, although more complex, are considered gold-standard treatment options.

Color Doppler Ultrasonography for the Evaluation of Subclavian Artery Stenosis

BACKGROUND

It is of great significance to evaluate symptomatic subclavian artery (SA) stenosis by color Doppler ultrasonography. More than 50% SA stenosis may induce symptoms. Currently, there is a paucity of published literature and lack of practitioner consensus for how ultrasonic findings should be interpreted in patients with SA stenosis.

OBJECTIVE

The study aimed to prospectively evaluate SA stenosis using color Doppler ultrasonography, with digital subtraction angiography as a reference. Moreover, we aimed to determine the optimal thresholds to predict SA stenosis (≥50%).

METHODS

A total of 423 SAs from 234 patients with normal or stenotic lumen were enrolled. The peak systolic velocity (PSV) and acceleration time at the stenotic and distal segments of the SA, peak reversed velocity of the vertebral artery, and waveforms of the stenotic SA, distal SA, and vertebral artery were recorded. The ratios of stenotic PSV to distal PSV (PSVr) and distal AT to stenotic AT were also calculated. The optimal cutoff values were determined using receiver operating characteristic analysis.

RESULTS

All ultrasonic parameters were significantly correlated with the degree of SA stenosis, whereas PSV (r = 0.624, P < 0.001), PSVr (r = 0.654, P < 0.001) and VA waveform change (r = 0.631, P < 0.001) had the strongest correlation with SA stenosis. The optimal cutoff values were as follows: PSV ≥ 230 cm/s and PSVr ≥ 2.2 to predict ≥ 50% stenosis, and PSV ≥ 340 cm/s and PSVr ≥ 3.0 to predict ≥ 70% stenosis.

CONCLUSIONS

Symptomatic patients with the ultrasonic parameters of PSV ≥ 230 cm/s and PSVr ≥ 2.2 need to be considered for further verification by computed tomographic angiography or magnetic resonance angiography, or by digital subtraction angiography with a view to percutaneous transluminal angioplasty/stent implantation in the same session. The recommended graded cutoff values can help in long-term management of patients with SA stenosis.

"Asymptomatic" Subclavian Steal Syndrome

The definition of subclavian steal is subclavian artery occlusion or hemodynamically significant stenosis proximal to the origin of the vertebral artery that results in lower pressure in the distal subclavian artery. Although subclavian steal can often remain asymptomatic, if ignored, it can cause syncope or neurological deficits. Detailed routine evaluation of blood pressure and careful physical examination, simultaneously on both sides of patients at high vascular risk (such as those with hypertension, dyslipidemia, and diabetes), can assist in the early detection. Herein, we report the case of an 82-year-old male patient with steal syndrome, who had no subjective symptoms despite severe stenosis of the subclavian artery, with a marked left-right difference in blood pressure.

Posterior Circulation Ischemia in the Endovascular Era

BACKGROUND AND OBJECTIVES

To perform literature review of clinical, radiographic, and anatomical features of posterior circulation ischemia (PCI) and systematic review of the literature on the management of basilar artery occlusion (BAO) and associated outcomes.

METHODS

Review of literature was conducted to identify publications describing the risk factors, etiology, clinical presentation, and imaging for PCI. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. PubMed and Ovid MEDLINE were searched from 2009 to 2020 for articles relating to management of BAO. A synthesis was compiled summarizing current evidence on management of BAO.

RESULTS

PCI accounts for 15%-20% of strokes. Risk factors are similar to anterior circulation strokes. Dizziness (47%), unilateral limb weakness (41%), and dysarthria (31%) are the most common presenting symptoms. A noncontrast head CT will identify PCI in 21% of cases; diffusion-weighted MRI or CT perfusion increase sensitivity to 85%. Recent trials have shown endovascular therapy can achieve >80% recanalization of BAO. In select patients, 30%-60% who receive endovascular treatment can achieve favorable outcome vs without. A total of 13% achieve good outcome and there is an 86% mortality rate.

DISCUSSION

PCI can present with waxing and waning symptoms or clinical findings that overlap with stroke mimics and anterior circulation ischemia, making diagnosis more heavily dependent on imaging. Recanalization is an important predictor of improved functional outcome and survival. In this endovascular era, trials of BAO are fraught with deterrents to enrollment. Despite limitations, endovascular treatment has shown improved outcome in select patients.

Prevalence and Clinical Characteristics of Subclavian Steal Phenomenon/Syndrome in Patients with Acute Ischemic Stroke

There are no published clinical studies regarding the prevalence of subclavian steal among acute ischemic stroke patients. The aim of this study was to evaluate the prevalence and clinical significance of subclavian steal among a large number of consecutive ischemic stroke patients. Materials and methods: We reviewed the medical records of 2192 consecutive cases of acute ischemic stroke at a tertiary neurology clinic in Targu Mures, Romania, between 2018 and 2020. In total, 47 patients (2.2%) were diagnosed with subclavian steal phenomenon/syndrome. Results: Stroke patients with associated steal phenomenon were significantly younger (64.2 ± 11.1 versus 70.2 ± 12.8, p = 0.005) and predominantly male (68.1%). From among the 47 patients with subclavian steal phenomenon, nine (19.1%) presented stroke symptomatology in the vertebrobasilar territory. Overall, 83.3% of the stroke patients with associated steal phenomenon presented cerebral infarction and 16.7% presented TIA. There was no difference between groups regarding the affected vascular territory (VB versus carotid). Large artery atherosclerosis was more frequent in the stroke group with associated steal phenomenon (81.3% versus 43.5%, p = 0.0033). The NIHSS score at admission was higher in the patient group with associated steal phenomenon, but there was no difference in mRS at discharge. Associated carotid artery occlusion was more frequent in the stroke group with steal phenomenon (p < 0.01). Smoking and peripheral arteriopathy were more frequent in the patient group with associated steal phenomenon. Of the nine symptomatic patients, five underwent revascularization treatment. Conclusions: The prevalence of subclavian steal phenomenon among acute ischemic stroke patients was not higher than in other cohorts with heterogenous peripheral vascular pathologies. Similar to the general population, in acute ischemic stroke patients, the associated subclavian steal behaved like a benign hemodynamical condition, without severe consequences.

Asymmetric distribution of pathogenic low wall shear stress of the bilateral subclavian arteries: two case reports

The effects of increasing blood flow on the pathogenic wall shear stress (pWSS) of subclavian arteries (SAs) are currently unclear. Patient-specific models of the SA were constructed based on computed tomographic images from two patients. Using the Ansys Fluent 19.0 transient laminar flow solver, the finite volume method was chosen to solve the Navier–Stokes equation governing fluid behavior. The time-averaged wall shear stress, ratio of risk area, cumulative ratio of risk area (P¯), ratio of risk time, and ratio contour of risk time were calculated to describe the temporal and spatial distributions of pWSS. Virtually all pWSS occurred during the diastolic phase. The P¯ was 2.3 and 1.29 times higher on the left than on the right in Patients 1 (P1) and 2 (P2), respectively. Increasing the blood flow volume of the left SA by 20%, 40%, and 60% led to a 9.27%, 15.10%, and 20.99% decrease in P¯ for P1 and a 5.74%, 11.55%, and 17.14% decrease in P¯ for P2, respectively, compared with baseline values. In conclusion, the left SA showed greater diastolic pWSS than the right SA, and increasing the blood flow volume reduced the pWSS in the left SA.

Symptomatic subclavian steal syndrome: Report of four Moroccan cases and literature review

Introduction

Subclavian steal syndrome (SSS) is the hemodynamic phenomenon of blood flow reversal in the vertebral artery due to significant stenosis or occlusion of the proximal ipsilateral subclavian artery.

Materials and methods

Four patients with subclavian steal syndrome were treated in our center. Percutaneous radial approach was used for angioplasty, primary stenting of subclavian artery was performed, surgical techniques in particular carotid-subclavian bypass and carotid-subclavian transposition were used.

Results

We report the cases of four patients, three of which are male, with an average age of 60 years. All of them were symptomatic. Diagnosis was made by duplex ultrasound, supplemented by CT-angiography and arteriography. Endovascular treatment was attempted in all four patients, which was successful in two patients, who underwent primary stenting, and failed for the two others, for whom surgical treatment was considered. One had a subclavio-carotid bypass graft with a polytetrafluorethylene (PTFE) prosthesis and the other had a subclavio-carotid transposition. The technical results were satisfactory in all patients with symptoms resolution. The postoperative evolution was without notable complications and the postoperative checkups were satisfactory.

Discussion

There are excellent screening tools and effective medical therapies which can be instituted if the SSS is diagnosed early. When the need for revascularization arises, percutaneous modalities are favored given their proven long-term efficacy, decreased morbidity and mortality, and cost-effectiveness. Nevertheless, large, prospective, randomized and controlled trials are needed to compare the long-term patency rates between the endovascular and surgical techniques.

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SSS is caused by the reversal of blood flow in the vertebral artery.

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Doppler ultrasound is the ultimate screening tool for diagnosis.

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Treatment of symptomatic SSS is always indicated.

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Endovascular approach is the first-line treatment.

Angioplasty and stenting for symptomatic stenosis of the left subclavian artery complicated with aortic dissection

BACKGROUND

Aortic dissection is a rare but severe complication of percutaneous transluminal angioplasty and stenting (PTAS) for stenosis of the subclavian artery (SA). This retrospective study was designed to evaluate the risk factors and outcomes of patients with severe stenosis of the SA who underwent PTAS complicated by aortic dissection.

METHODS

Between 1999 and 2018, 169 cases of severe symptomatic stenosis of the SA underwent PTAS at our institute. Of them, six cases complicated by aortic dissection were included in this study. We evaluated the demographic features, technical factors of PTAS, and clinical outcomes in these six patients.

RESULTS

Aortic dissection occurred in 5.3% (6/113) of all left SA stenting cases but in none of the right SA stenting cases. All patients had hypertension and a high severity of SA stenosis (85.0 ± 13.0%, 60%-95%). Five of the six patients received balloon-expandable stents (83.3%). All patients had spontaneous resolution of the aortic dissection with conservative treatment. In a 63.33 ± 33.07 (7-118) month follow-up, five of the six patients (83.3%) had long-term symptom relief and stent patency.

CONCLUSION

Aortic dissection occurred in patients who underwent PTAS for severe stenosis of the left SA, mainly with balloon-expandable stents. We suggest using self-expandable stents and angioplasty with an undersized balloon during PTAS for severe stenosis of the left proximal SA to prevent aortic dissection.

Coronary Subclavian Steal Syndrome With Neurological Symptoms After Coronary Artery Bypass Grafting

Coronary subclavian steal syndrome (CSSS) is a complication of coronary artery bypass graft surgery with the left internal mammary artery that results from left subclavian artery stenosis. A reversal of flow in the left internal mammary artery results in ischemia of the heart. We present the case of a 54-year-old man with CSSS with the rare symptom of dizziness. This indicates a potential component of undiagnosed vertebral steal syndrome as well.

Coronary subclavian steal syndrome causing myocardial Infarction

Coronary subclavian steal syndrome (CSSS) is a rare complication of the internal mammary artery (IMA) grafting in coronary artery bypass surgery. The technical definition is myocardial ischemia due to the reduced flow of blood, or flow reversal in the IMA graft. This in most cases results from hemodynamically significant proximal subclavian artery stenosis. The clinical presentation is variable and ranges from unstable angina to myocardial infarction, and in some cases, sudden cardiac arrest. CSSS is an entity that is hard to diagnose if one is not actively looking for it. The clinical diagnosis is often complicated, and the prevalence of the disorder is frequently underestimated. In this case presentation, we report a case of myocardial infarction that resulted from significant proximal subclavian artery stenosis.

Ultrasound Assessment of Extracranial Carotids and Vertebral Arteries in Acute Cerebral Ischemia

Assessing ischemic etiology and mechanism during the acute phase of an ischemic stroke is crucial in order to tailor and monitor appropriate treatment and determine prognosis. Cervical Duplex Ultrasound (CDU) has evolved since many years as an excellent screening tool for the evaluation of extracranial vasculature. CDU has the advantages of a low cost, easily applicable, bed side examination with high temporal and spatial resolution and without exposing the patients to any significant complications. It represents an easily repeatable test that can be performed in the emergency room as a first-line examination of cervical artery pathology. CDU provides well validated estimates of the type of the atherosclerotic plaque, the degree of stenosis, as well as structural and hemodynamic information directly about extracranial vessels (e.g., subclavian steal syndrome) and indirectly about intracranial circulation. CDU may also aid the diagnosis of non-atherosclerotic lesions of vessel walls including dissections, arteritis, carotid-jugular fistulas and fibromuscular dysplasias. The present narrative review outlines all potential applications of CDU in acute stroke management and also highlights its potential therapeutic implications.

Coronary Subclavian Steal Syndrome: A Contemporary Review

Coronary subclavian steal syndrome (CSSS) is a rare cause of angina. It occurs in patients with prior coronary artery bypass grafting and, specifically, a left internal mammary artery (LIMA) to left anterior descending artery (LAD) graft and co-existent significant subclavian artery stenosis. In this context, there is retrograde blood flow through the LIMA to LAD graft to supply the subclavian artery beyond the significant stenosis. This potentially occurs at the cost of compromising coronary artery perfusion dependent on the LIMA graft. In this review, we present a case of a middle-aged female who suffered from CSSS and review the literature for the contemporary diagnosis and management of this condition.

An Interesting Observation Regarding Retrograde Vertebral Artery Flow in Patients With Dialysis Access Fistulas

OBJECTIVES

Retrograde vertebral artery flow, the steal phenomenon, is most frequently caused by a flow-limiting stenosis of the proximal subclavian artery. The reversal of flow can be incomplete, resulting in bidirectional flow: retrograde in systole and antegrade in diastole. Less often, retrograde vertebral artery flow is the consequence of increased subclavian flow, as might occur with a well-functioning dialysis access fistula. Our objective was to evaluate bidirectional vertebral artery flow associated with dialysis access fistulas.

METHODS

We retrospectively reviewed the direction of flow through the vertebral artery in systole and diastole of 335 patients with dialysis fistulas who had undergone extracranial cerebral vascular Doppler examinations.

RESULTS

Fifteen patients had retrograde flow in their vertebral artery ipsilateral with the side of their fistula. There was completely reversed flow in 1 patient and bidirectional flow in the other 14. For each of these 14, the flow was antegrade in early systole and retrograde in diastole. Compression of the fistula restored the antegrade flow.

CONCLUSIONS

Under conditions of reduced subclavian artery flow, bidirectional vertebral artery flow will be retrograde in early systole and antegrade in diastole. Under conditions of increased subclavian artery flow, bidirectional flow through the vertebral artery will be antegrade in early systole and retrograde in diastole.

HEMODYNAMIC INVESTIGATION OF SUBCLAVIAN-CORONARY STEAL SYNDROME IN DIALYSIS PATIENTS WITH CORONARY ARTERY OCCLUSION AND DIFFERENT STENOSIS PERCENTAGES IN SUBCLAVIAN ARTERY

Purpose: Diseases of the coronary arteries represent critical cardiovascular bleakness and mortality around the world. The main focus of this study is to simulate hemodialysis patients undergoing Coronary Artery Bypass Graft (CABG) surgery by the left internal mammary artery. The survey is to investigate whether subclavian-coronary steal syndrome will occur in patients with stenosis in their left subclavian.

Methods: A three-dimensional model of Brachial—Radial—Ulnar tree arterial system and dialysis graft are constructed and then simulated by the implementation of fluid–structure interaction (FSI) and non-FSI models. After consent was obtained, data attributed to dialysis patients who had undergone coronary bypass surgery at the Tehran Heart Center (THD) was collected.

Results: Stenosis in the subclavian artery causes the left internal mammary artery (LIMA) graft to lack flow that, in CABG cases, is supplying the heart muscle. With the increase of stenosis from zero to 54%, the flow results show a negative flow indicating reversed flow in the artery. Meanwhile, the comparison between flow quantity of a normal Left Anterior Descending (LAD) and LIMA in case of 38% stenosis in subclavian shows that the amount of flow reaching the heart is less than standard. The threshold stenosis in the subclavian artery for which subclavian-coronary steal phenomena occurs is simulated to be around 54%. Furthermore, investigation of the effect of flow quantity in cases of hemodialysis versus nonhemodialysis shows that the flow is lessened in case of hemodialysis.

Conclusions: In hemodialysis patients with more than 38% stenosis in left subclavian, it is well advised that LIMA bypass graft is not the preferred graft choice, and at 54% of subclavian stenosis, the steal phenomenon occurs.

Coronary-subclavian steal syndrome, an easily overlooked entity in interventional cardiology

Coronary-subclavian steal syndrome (CSSS) is a severe complication of coronary artery bypass graft (CABG) surgery with internal mammary artery grafting. It is caused by functional graft failure due to a hemodynamically significant proximal subclavian artery stenosis. In this manuscript, we provide a comprehensive review of literature and we report a series of five consecutive CSSS cases. This case series illustrates the variable clinical presentation, thereby emphasizing the importance of raised awareness concerning this pathology in CABG patients.

Periprocedural and Long-Term Outcomes of Stent Implantation for De Novo Subclavian Artery Disease

INTRODUCTION

The purpose of the current study was to investigate the periprocedural and long-term outcomes of stent implantation for de novo subclavian artery (SCA) disease.

MATERIAL AND METHODS

We retrospectively investigated consecutive patients with de novo SCA lesions undergoing elective endovascular therapy procedures at our center between April 2004 and September 2015. All patients were included in the analyses of periprocedural outcomes, including procedural and clinical success. Subsequently, patients who completed the clinical follow-up and were assessed with brachial systolic pressure differences between the diseased and the contralateral arms, or angiographic stenosis, after stent implantation with procedural success were included in the analyses of long-term outcomes, including primary patency.

RESULTS

There were 62 patients (median 71.0 years, interquartile range 65.3-76.0 years; 45 men) with 62 de novo SCA lesions included in the analyses of periprocedural outcomes. There were 46 stenoses (74.2%) and 16 occlusions (25.8%). Our results indicated high procedural success rates for overall (95.2%), stenotic (97.8%), and occlusive (87.5%) lesions. Similarly, high clinical success rates were observed for overall (91.9%), stenotic (93.5%), and occlusive (87.5%) lesions. The median follow-up time was 6.0 years (interquartile range, 2.6-8.3 years). There were 48 patients with 48 de novo SCA lesions included in the analyses of long-term outcomes. Primary patency estimates were 97.7% (1 year), 97.7% (3 years), 93.1% (5 years), and 87.6% (7 years). Also, we observed a high estimate for freedom from reintervention for the target vessel (93.8%).

CONCLUSION

Stent implantation for de novo SCA disease can be performed successfully and safely with favorable periprocedural and long-term outcomes.

[Subclavian artery stenosis combined with vertebral artery stenosis may lead to compensatory blood flow changes in the contralateral vertebral artery]

OBJECTIVE

To investigate the severity of blood steal and the hemodynamic profiles in patients with subclavian artery stenosis combined with vertebral artery stenosis.

METHODS

A retrospective analysis was performed of transcranial Doppler (TCD) data from patients with subclavian artery stenosis (SAS) and concomitant unilateral/bilateral vertebral artery stenosis (VAS, &gt;50%) or occlusion in our institution between February, 2014 and July, 2018.Thirty-seven patients with SAS combined with VAS (SAS+VAS) were reviewed for types of blood steal, peak systolic velocities of blood flow in affected subclavian artery and the contralateral vertebral artery, and the findings of hyperemia testing.These data were also reviewed for 39 SAS patients without VAS (control group) for comparison of blood steal and hemodynamic profiles.

RESULTS

In SAS+VAS group, 5 patients showed no blood steal; blood steal in stage Ⅰ was found in 22 patients, stage Ⅱ in 7, and stage Ⅲ in 3, as compared to the numbers of 17, 12 and 10 in the control group, respectively (H=9.431, P=0.002).The peak systolic velocity of the contralateral vertebral artery was 43.91±17.43 cm/s in SAS+VAS group, significantly lower than that in the control group (53.56±17.45 cm/s; t= 629.5, P=0.006).Hyperemia testing showed a significant difference in the negative rate between SAS+VAS group and the control group[35.1%(13/37) vs 7.7%(3/39);χ²=8.603, P=0.003).

CONCLUSIONS

SAS combined with VAS may lead to reduced compensatory blood flow in the contralateral vertebral artery to lessen the severity of subclavian steal syndrome.