China
Africa
Explore chapters and articles related to this topic
Stroke
Published in Jahangir Moini, Matthew Adams, Anthony LoGalbo, Complications of Diabetes Mellitus, 2022
Jahangir Moini, Matthew Adams, Anthony LoGalbo
Most transient ischemic attacks are caused by emboli that usually come from the carotid or vertebral arteries. Rarely, TIAs occur from impaired perfusion caused by severe hypoxemia, a lowered oxygen-carrying capacity of the blood, or increased viscosity – especially in arteries of the brain that have become stenotic. Reduced oxygen-carrying capacity of the blood may be caused by extreme anemia or carbon monoxide poisoning. Increased viscosity may be due to severe polycythemia. Cerebral ischemia is usually not caused by systemic hypotension unless it is extreme or there is preexisting arterial stenosis. This is because autoregulation regulates blood flow in the brain, to be nearly normal over widely ranging systemic blood pressure. Subclavian steal syndrome involves a subclavian artery that is stenosed, proximal to the start of the vertebral artery. The stenosed artery “steals” blood from the vertebral artery. The blood flow becomes reversed in the vertebral artery. Since the vertebral artery supplies the arms during physical exertion, there are signs of vertebrobasilar ischemia. Sometimes, a TIA can occur in a child that has an extreme cardiovascular disorder producing emboli, or with very high hematocrit levels.
Dizziness
Published in Henry J. Woodford, Essential Geriatrics, 2022
Subclavian steal syndrome is a potential, although rare, cause of similar symptoms. In some cases, it may result in syncope.18 It is caused by an occlusion of the proximal subclavian artery which results in retrograde blood flow in the ipsilateral vertebral artery (i.e. ‘steal' of the blood flow to the brainstem). This is usually secondary to atheromatous disease. Characteristically, symptoms are provoked by vigorous exercise of the affected arm. Physical signs include absent pulses, a difference in blood pressure of > 20 mmHg between the arms and a supraclavicular bruit. Diagnosis is made by demonstrating retrograde flow in the vertebral artery with Doppler studies or angiography. Treatment involves addressing vascular risk factors and considering revascularisation procedures such as angioplasty.
Cardiovascular system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The vertebral arteries are similarly assessed using colourflow and spectral Doppler in order to determine whether there is antegrade flow, in other words the normal direction towards the head and brain, or abnormal retrograde flow away from the head. A vertebral artery is shown in Fig. 9.48a; the colour has been used in this instance to help identify the anatomy, which can be difficult to visualise. Figure 9.48b shows retrograde flow in the vertebral artery. This is indicative of subclavian steal syndrome, caused by blood pressure differentials and suggestive of severe stenosis or even occlusion in the subclavian artery proximal to the origin of the vertebral artery. Blood is ‘stolen’ from the vertebral artery to perfuse the arm, causing the retrograde flow.
Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners
Published in Clinical and Experimental Optometry, 2022
Michael Kalloniatis, Henrietta Wang, Paula Katalinic, Angelica Ly, Warren Apel, Lisa Nivison-Smith, Katherine F Kalloniatis
Activities in the extremities (right or left arm use) may lead to symptoms consistent with vertebro-basilar insufficiency (due to subclavian steal syndrome). Reduction in cerebral blood flow may occur secondary to atherosclerosis of the innominate arteries that supply the upper extremities.32,34–36 Patients may experience visual disturbance, either monocular or binocular, after the use of the right or left arms due to steal syndrome. Subclavian steal syndrome occurs due to blockage of the subclavian artery proximal to the origin of the vertebral artery: blood supply entering the circulation via the carotids is diverted via the Circle of Willis back through the basilar artery to supply the innominate artery (Figure 1(a)).26,37
Dynamic observation on collateral circulation construction of patient with vertebral artery restenosis after stenting: case report
Published in International Journal of Neuroscience, 2021
Yan-Wei Yin, Qian-Qian Sun, Da-Wei Chen, Fa-Guo Zhao, Jin Shi
A male patient aged 71 years was admitted for two weeks of lightheadedness and three episodes of loss of consciousness in 2015. This patient had a history of bilateral subclavian artery stenting, which were respectively performed in 2005 and 2008 due to the subclavian artery stenosis. At that time he was suffering from subclavian steal syndrome. Besides, this patient had a history of pharmacologically treated hyperlipidemia, hypertension, and smoking habit. On admission, his blood pressure was 156/82 mmHg, pulse was 82 beats/minute, and neurological examination was normal. Then the vascular ultrasound of the neck suggested a stenosis of the left vertebral artery, and 24-h dynamic electrocardiogram and echocardiography did not show any obvious abnormal changes. Informed consent was obtained. DSA demonstrated the bilateral subclavian artery was kept open, but there was a severe stenosis of at least 75% of the left vertebral artery at its origin which likely related to an underlying severe atherosclerotic stenosis (Figure 1a, b). In addition, a moderate stenosis was also found in the origin of right vertebral artery (Figure 1c). It was decided that the patient should be given left vertebral artery stenting in an effort to resolve the vascular stenosis (Figure 1d). In addition, dual antiplatelet therapy with aspirin and clopidogrel and drugs to lower lipids and control blood pressure were administered. After stenting and aggressive medical management, the patient achieved a complete remission. Notably, at this time no collateral flow was found supplying flow to the left vertebral artery, either external carotid collateral branches or thyrocervical trunk (Figure 1e, f).
Systolic murmur in disguise: subclavian artery stenosis as an overlooked cause of missed case of hypertension
Published in Blood Pressure, 2021
Jana Brguljan-Hitij, Giuseppe Ambrosio, Tadej Žlahtič
When collecting medical history, physicians should be attentive to certain symptoms, which include ischaemic claudication in upper extremities, or emboli to hands [1]. In particularly severe cases, it can be presented as subclavian steal syndrome with syncope, vertigo, light-headedness, diplopia, dysarthria, dysphagia, ataxia, numbness, nystagmus, blurred vision, transient ischaemic attacks [4]. It can even cause myocardial ischaemia in patients that had undergone coronary artery bypass graft surgery with left internal mammary arteryorintermittent ischaemic claudications in patients that underwent axillo-femoral bypass graft surgery [2].