Pseudo subclavian steal syndrome: Case report

Subclavian steal syndrome: a case study of diagnosis, management, and successful surgical resolution

Subclavian steal syndrome (SSS) is a rare vascular condition characterized by retrograde blood flow in the vertebral artery, often discovered incidentally in asymptomatic patients. We present a 65-year-old male with recurrent transient ischemic attacks (TIAs) attributed to 99% stenosis at the origin of the left subclavian artery, leading to SSS. Diagnostic modalities included duplex ultrasound, confirming inverted left vertebral artery flow, and multi-slice computed tomography angiography, confirming the diagnosis. Despite an unsuccessful attempt at balloon angioplasty, successful vascular surgery was performed, establishing a left carotid-vertebral artery bypass. The patient recovered well without complications. This case underscores the importance of considering SSS in TIA cases, utilizing non-invasive diagnostic tools, and highlighting the successful management of symptomatic SSS through surgical intervention.

Vascular flow limitations affecting the cervico-cranial region: Understanding ischaemia

BACKGROUND

Blood flow and brain ischaemia have been of interest to physical therapists for decades. Despite much debate, and multiple publications around risk assessment of the cervical spine, more work is required to achieve consensus on this vital, complex topic. In 2020, the International Federation of Orthopaedic Manipulative Physical Therapists (IFOMPT) Cervical Framework adopted the dubious terminology 'vascular pathologies of the neck', which is misleading, on the premise that 1) not all flow limitations leading to ischaemia, are associated with observable blood vessel pathology and 2) not all blood flow limitations leading to ischaemia, are in the anatomical region of the 'neck'.

OBJECTIVE

This paper draws upon the full body of haemodynamic knowledge and science, to describe the variety of arterial flow limitations affecting the cervico-cranial region.

DISCUSSION

It is the authors' contention that to apply clinical reasoning and appropriate risk assessment of the cervical spine, there is a requirement for clinicians to have a clear understanding of anatomy/anatomical relations, the haemodynamic science of vascular flow limitation, and related pathologies. This paper describes the wide range of presentations and haemodynamic mechanisms that clinicians may encounter in practice. In cases with a high index suspicion of vascular involvement or an adverse response to assessment/intervention, appropriate referral should be made for further investigations, using consistent terminology. The term 'vascular flow limitation' is proposed when considering the range of mechanisms at play. This fits the terminology used (in vascular literature) at other anatomical sites and is understood by medical colleagues.

Recurrent Subclavian Steal Syndrome: A Novel Case of Vasculopathy

Subclavian steal syndrome (SSS) refers to the phenomenon of retrograde flow in an ipsilateral branch of the subclavian artery due to hemodynamically significant stenosis or occlusion of the ipsilateral proximal subclavian artery. While SSS is usually asymptomatic, it can manifest as vertebrobasilar insufficiency (VBI), ischemia of the affected extremity, or cardiac angina when an internal mammary artery (IMA) is used as a bypass graft. The underlying etiology is most often atherosclerosis but can include Takayasu arteritis, thoracic outlet syndrome, cervical rib, and stenosis secondary to surgical repair of aortic coarctation or tetralogy of Fallot. There are several case reports describing unique presentations of SSS as well as limited reports of double SSS, where the brachiocephalic steno-occlusive disease causes flow reversal in both the ipsilateral vertebral and carotid arteries. We report herein the first documented case, to our knowledge, of a patient with SSS previously treated with left subclavian artery stenting and left common carotid-subclavian bypass who developed recurrent SSS in conjunction with orthostatic cerebral hypoperfusion syndrome (OCHOS) secondary to severe vasculopathy. She presented with recurrent, paroxysmal vertigo and near-syncope associated with left upper extremity paresthesias that would only abate with sitting in the context of left subclavian artery stent restenosis and occlusion of her left common carotid-subclavian bypass graft. Interestingly, her initial presentation entailed retrograde flow from the left vertebral artery to the left subclavian artery, classic for SSS, but recurrence of her SSS involved retrograde flow from the left common carotid artery to the left subclavian artery, a phenomenon which has also not been described in the literature to our knowledge. As her symptoms of VBI appeared to be triggered by standing and not left arm movement, they were considered to be primarily secondary to OCHOS. Consequently, her primary treatment was to increase salt and fluid intake and thus increase intravascular volume for improved cerebral perfusion as she was not deemed to be a suitable candidate for regrafting of the left subclavian artery.

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.

Early changes of NLRP3 inflammasome activation after hypoxic-ischemic brain injury in neonatal rats

The pathogenesis of neonatal hypoxic-ischemic (HI) brain injury may involve activation of the NOD-like receptor family pyrin domain-containing-3 (NLRP3) inflammasome and its downstream effectors, caspase-1 and interleukin (IL)-1β. The start time of therapy is associated with adverse neurodevelopmental outcome following HI injury. We performed this study investigating early dynamic changes in NLRP3, caspase-1, and IL-1β expression during the first 24 h following HI brain injury in an animal model, in order to optimize selection of treatment time after injury. Rats were randomized to an HI group (n=40) and sham group (n=40). Rats in the HI group were subjected to right common carotid artery ligation and then exposed to hypoxia (8% O₂) for 2 h, and divided into 5 subgroups with 8 cases in each group at 5 postoperative time points (0, 4, 8, 12, 24 h). Brain injury during the first 24 h after surgery/hypoxia was evaluated by cranial ultrasonography. RT-PCR, western blot, and immunohistochemistry were applied to determine protein and mRNA expressions. In the HI group, ultrasonography revealed accelerated right vertebrobasilar artery flow at 4 h, enhanced brain parenchyma echogenicity at 24 h, and blood stealing from the vertebrobasilar artery at 24 h. In the HI group, immunohistochemistry demonstrated elevated expressions of NLRP3 and IL-1β at 4, 8, 12, and 24 h and enhanced expression of caspase-1 at 8 and 12 h (all P < 0.01). Western blot and RT-PCR revealed that, compared with the sham group, the HI group exhibited elevated expression of NLRP3 at 4, 8, and 24 h, caspase-1 at 12 h, and IL-1β at 8 h (all P < 0.05). In summary, the present results suggested that activation of NLRP3/caspase-1/IL-1β signaling occurs within 4 h of HI brain injury in the neonatal rat.