Subclavian steal syndrome

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.

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.

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.

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.

Evaluation of severe subclavian artery stenosis by color Doppler flow imaging

This study evaluates the diagnostic value of the hemodynamic parameters of color Doppler flow imaging (CDFI) for severe (70 to 99%) subclavian artery stenosis (SAS) using digital subtraction angiography (DSA) as the reference standard. Two-hundred fifty-two patients with suspected SAS were recruited into the study and examined from June 2005 to December 2009. The degree of stenosis was classified as moderate (50 to 69%) or severe (70 to 99%) stenosis. By using CDFI, the residual diameter (Dr), peak systolic velocity (PSV1) and end diastolic velocity (EDV) at the stenotic vessel segments, as well as the original diameter (Do) and PSV2 of the relative normal segments distal to the stenosis (the segment distal to the poststenotic dilation) were recorded. The diameter stenosis rate (1-Dr/Do) and PSV ratio (PSV1/PSV2) were calculated. Using DSA as the reference standard, the diagnostic values and optimal cutoff values for each parameter for the evaluation of severe (70%-99%) were determined using receiving operating characteristic curve analysis. Among the 252 patients, 109 patients were diagnosed as having severe (70 to 99%) SAS and 143 patients had moderate (50 to 69%) SAS. The optimal cutoff values for PSV1, EDV and the PSV1/PSV2 ratio for evaluating severe (70 to 99%) SAS were PSV1 ≥343 cm/s, EDV ≥60 cm/s and PSV1/PSV2 ≥4.0, respectively. The accuracy for diagnosing SAS with PSV1 (86.1%) was higher than that of EDV (85.7%), PSV1/PSV2 (84.9%) and 1-Dr/Do (80.2%). In addition, when PSV1 was used in combination with EDV and 1-Dr/Do, the accuracy for diagnosing SAS increased from 86.1% to 87.3%. When PSV1 was used in combination with EDV and PSV1/PSV2, the accuracy for diagnosing SAS reached 95.8%. In conclusion, the CDFI hemodynamic parameters of PSV1, EDV and PSV1/PSV2 show good consistency with DSA for diagnosing severe (70 to 99%) SAS, and a combination of these three parameters can ensure even greater accuracy for diagnosing SAS.

Facial steal syndrome: identification and endovascular management

We describe a case of intraprandial vertebro-basilar insufficiency secondary to posterior cerebral circulation ischemia. Secondary collateralization was seen from facial and external carotid artery branches to the posterior circulation causing facial arterial steal during mastication. This condition was treated endovascularly. Occluded common and external carotid arteries were revascularized via angioplasty and stenting. The patient was able to undergo coronary artery bypass and right hip replacement in the following two months without cerebrovascular complications.

Pathways of neonatal stroke and subclavian steal syndrome

Neonatal stroke may occur silently. Identification of potential embolic pathways unique to the neonate is important when investigating the aetiology of infarction and arterial occlusion, and preventing further episodes. This is a case report of an infant with venous thrombus embolising across the foramen ovale causing cerebral infarction and subclavian artery steal syndrome, without neurological signs.

The development of a novel mouse model of transient global cerebral ischemia

A reproducible model of global cerebral ischemia in mice is essential for elucidating the molecular mechanism(s) of neuronal damage induced by cerebral ischemia/reperfusion injury. In the present study, we developed a mouse model of transient global ischemia induced by occlusion of the bilateral common carotid arteries and the left subclavian artery together with right subclavian artery (RSA) stenosis (CSOSS) under controlled ventilation in C57BL/10ScSn mice. The mean arterial blood pressure was maintained in the physiological range. The cortical cerebral blood flow was reduced to less than 10% of the pre-ischemic value. Twelve minutes of global ischemia induced brain damage in several brain structures. The neuropathological score in the hippocampus CA1 region was 1.7, 3.5 and 3.7 following reperfusion for 24, 48 and 72 h, respectively. Less extensive damage was seen in the dentate gyrus and cortical regions, compared with the CA1 region. Damage was observed in these regions 24h after ischemia and was not different between 48 and 72 h post-ischemia. Results indicated that this global ischemia model possessed several advantages, including reproducible cerebral ischemic insult, sufficient reperfusion and low mortality rate (10%), and could be used for studies on cerebral ischemia/reperfusion injury in mice.