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55篇 您的检索式:作者名="David Spence"
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1Cardioembolic stroke:everything has changed显示文摘Historically,because of the difficulty of using warfarin safely and effectively,many patients with cardioembolic stroke who should have been anticoagulated were instead given ineffective antiplatelet therapy(or no antithrombotic therapy).With the arrival of new oral anticoagulants that are not significantly more likely than aspirin to cause severe haemorrhage,everything has changed.Because antiplatelet agents are much less effective in preventing cardioembolic stroke,it is now more prudent to anticoagulate patients in whom cardioembolic stroke is strongly suspected.Recent advances include the recognition that intermittent atrial fibrillation is better detected with more prolonged monitoring of the cardiac rhythm,and that percutaneous closure of patent foramen ovale(PFO)may reduce the risk of stroke.However,because in most patients with stroke and PFO the PFO is incidental,this should be reserved for patients in whom paradoxical embolism is likely.A high shunt grade on transcranial Doppler saline studies,and clinical clues to paradoxical embolism,can help in appropriate selection of patients for percutaneous closure.For patients with atrial fibrillation who cannot be anticoagulated,ablation of the left atrial appendage is an emerging option.It is also increasingly recognised that high levels of homocysteine,often due to undiagnosed metabolic deficiency of vitamin B_(12),markedly increase the risk of stroke in atrial fibrillation,and that B vitamins(folic acid and B_(12))do prevent stroke by lowering homocysteine.However,with regard to B_(12),methylcobalamin should probably be used instead of cyanocobalamin.Many important considerations for judicious application of therapies to prevent cardioembolic stroke are discussed.J David Spence 2018Stroke & Vascular Neurology2018,3,2:10
2How to identify which patients with asymptomatic carotid stenosis could benefit from endarterectomy or stenting显示文摘Offering routine carotid endarterectomy(CEA)or carotid artery stenting(CAS)to patients with asymptomatic carotid artery stenosis(ACS)is no longer considered as the optimal management of these patients.Equally suboptimal,however,is the policy of offering only best medical treatment(BMT)to all patients with ACS and not considering any of them for prophylactic CEA.In the last few years,there have been many studies aiming to identify reliable predictors of future cerebrovascular events that would allow the identification of patients with high-risk ACS and offer a prophylactic carotid intervention only to these patients to prevent them from becoming symptomatic.All patients with ACS should receive BMT.The present article will summarise the evidence suggesting ways to identify these high-risk asymptomatic individuals,namely:(1)microemboli detection on transcranial Doppler,(2)plaque echolucency on Duplex ultrasound,(3)progression in the severity of ACS,(4)silent embolic infarcts on brain CT/MRI,(5)reduced cerebrovascular reserve,(6)increased size of juxtaluminal hypoechoic area,(7)identification of intraplaque haemorrhage using MRI and(8)carotid ulceration.The evidence suggests that approximately 10%-15%of patents with asymptomatic stenosis might benefit from intervention;this will become more clear after publication of ongoing studies comparing stenting or endarterectomy with best medical therapy.In the meantime,no patient should be offered intervention unless there is evidence of high risk of ipsilateral stroke,from modalities such as those discussed here.Kosmas I Paraskevas Frank J Veith J David Spence 2018Stroke & Vascular Neurology2018,3,2:10
3Blood pressure gradients in cerebral arteries:a clue to pathogenesis of cerebral small vessel disease显示文摘rationale The role of hypertension in cerebral small vessel disease is poorly understood.At the base of the brain(the‘vascular centrencephalon’),short straight arteries transmit blood pressure directly to small resistance vessels;the cerebral convexity is supplied by long arteries with many branches,resulting in a drop in blood pressure.Hypertensive small vessel disease(lipohyalinosis)causes the classically described lacunar infarctions at the base of the brain;however,periventricular white matter intensities(WMIs)seen on MRI and WMI in subcortical areas over the convexity,which are often also called‘lacunes’,probably have different aetiologies.Objectives We studied pressure gradients from proximal to distal regions of the cerebral vasculature by mathematical modelling.Methods and results Blood flow/pressure equations were solved in an Anatomically Detailed Arterial Network(ADAN)model,considering a normotensive and a hypertensive case.Model parameters were suitably modified to account for structural changes in arterial vessels in the hypertensive scenario.Computations predict a marked drop in blood pressure from large and medium-sized cerebral vessels to cerebral peripheral beds.When blood pressure in the brachial artery is 192/113 mm Hg,the pressure in the small arterioles of the posterior parietal artery bed would be only 117/68 mm Hg.In the normotensive case,with blood pressure in the brachial artery of 117/75 mm Hg,the pressure in small parietal arterioles would be only 59/38 mm Hg.conclusion These findings have important implications for understanding small vessel disease.The marked pressure gradient across cerebral arteries should be taken into account when evaluating the pathogenesis of small WMIs on MRI.Hypertensive small vessel disease,affecting the arterioles at the base of the brain should be distinguished from small vessel disease in subcortical regions of the convexity and venous disease in the periventricular white matter.Pablo J Blanco Lucas O Müller J David Spence 2017Stroke & Vascular Neurology2017,2,3:9
4Controlling resistant hypertension显示文摘Resistant hypertension(failure to achieve target blood pressures with three or more antihypertensive drugs including a diuretic)is an important and preventable cause of stroke.Hypertension is highly prevalent in China(>60%of persons above age 65),and only~6%of hypertensives in China are controlled to target levels.Most strokes occur among persons with resistant hypertension;approximately half of strokes could be prevented by blood pressure control.Reasons for uncontrolled hypertension include(1)non-compliance;(2)consumption of substances that aggravated hypertension,such as excess salt,alcohol,licorice,decongestants and oral contraceptives;(3)therapeutic inertia(failure to intensify therapy when target blood pressures are not achieved);and(4)diagnostic inertia(failure to investigate the cause of resistant hypertension).In China,an additional factor is lack of availability of appropriate antihypertensive therapy in many healthcare settings.Sodium restriction in combination with a diet similar to the Cretan Mediterranean or the DASH(Dietary Approaches to Stop Hypertension)diet can lower blood pressure in proportion to the severity of hypertension.Physiologically individualised therapy for hypertension based on phenotyping by plasma renin activity and aldosterone can markedly improve blood pressure control.Renal hypertension(high renin/high aldosterone)is best treated with angiotensin receptor antagonists;primary aldosteronism(low renin/high aldosterone)is best treated with aldosterone antagonists(spironolactone or eplerenone);and hypertension due to overactivity of the renal epithelial sodium channel(low renin/low aldosterone;Liddle phenotype)is best treated with amiloride.The latter is far more common than most physicians suppose.J David Spence 2018Stroke & Vascular Neurology2018,3,2:4
5China Stroke Statistics 2019: a wealth of opportunities for stroke prevention显示文摘The China Stroke Statistics published in this issue of the journal1 represent an enormous undertaking.It included data on 3010204 patients who had a stroke admitted in 2018 to 1853 tertiary care hospitals and compiled data from multiple sources on stroke and stroke risk factors in China.The authors and the huge team of workers who must have compiled the statistics are to be commended on this enormous effort.In the report is a wealth of data on what is wrong in China to cause such a high risk of stroke but also a wealth of opportunity to make a difference.The reason this is so important is that~80%of strokes are preventable.J David Spence 2020Stroke & Vascular Neurology2020,5,3:3
6Association of homocysteine and smoking with cerebral microemboli in patients with mechanical heart valves:a transcranial Doppler study显示文摘Objectives Microembolic signals(MES)on transcranial Doppler(TCD)predict stroke and cognitive decline.Plasma levels of total homocysteine(tHcy),a prothrombotic factor,are higher in patients with microemboli in carotid stenosis and in patients with paradoxical embolism.In this study we assessed the association between the level of tHcy and the number of MES in patients with mechanical heart valves(MHVs).Methods TCD monitoring was performed to detect MES before and after breathing 100% oxygen and repeated every 2-4 weeks up to six times.results Twenty-five patients with MHVs(mean age:63.60±10.15 years)participated in this study;15 were men(66.47±7.25 years)and 10 were women(59.30±12.60 years).In total,there were 126 study visits.In multiple regression,higher tHcy was associated with more MES in both preoxygenation(OR 1.34(95%CI 1.07 to 1.68,P=0.009))and postoxygenation(OR 1.40(95% CI 1.07 to 1.83,P=0.01))phases.Current smoking and the length of time between the operation and monitoring also correlated with a higher number of MES before and after breathing oxygen,particularly in women.conclusions Higher tHcy and smoking were associated with a higher MES count in both preoxygenation and postoxygenation phases.Because smoking can be stopped and hyperhomocysteinaemia is treatable,these are clinically important findings.Alicia Mattia M Reza Azarpazhooh Claudio Munoz Chrysi Bogiatzi Mackenzie A Quantz J David Spence 2017Stroke & Vascular Neurology2017,2,4:2
7Validation of 3D Ultrasound Vessel Wall Volume: An Imaging Phenotype of Carotid Atherosclerosis显示文摘Micaela Egger J. David Spence Aaron Fenster Grace Parraga 2007Ultrasound in Medicine & Biology2007,,6:1
8Dietary Intervention to Reverse Carotid Atherosclerosis显示文摘Iris Shai J. David Spence Dan Schwarzfuchs Yaakov Henkin Grace Parraga Assaf Rudich Aaron Fenster Christiane Mallett Noah Liel-Cohen Amir Tirosh Arkady Bolotin Joachim Thiery Georg Martin Fiedler Matthias Blüher Michael Stumvoll Meir J. Stampfer 2010Circulation2010,,10:1
9Performance analysis of a feasible air-cycle refrigeration system for road transport 显示文摘Stephen W T Spence W John Doran David Wart 2005International Journal of Refrigeration2005,,28:1
10Combined iliac angioplasty and infrainguinal revascularization surgery are effective in diabetic patients with multilevel arterial disease显示文摘Peter L. Faries MD David Brophy MD Frank W. LoGerfo MD Cameron M. Akbari MD David R. Campbell MD Liam D. Spence MD Shannon C. Hook BA Frank B. Pomposelli MD 2001Annals of Vascular Surgery2001,,1:1
11Three-dimensional Ultrasound quantification of inten- sive statin treatment of carotid atherosclerosis显示文摘ADAM KRASINSKI BERNARD CHIU J DAVID SPENCE 2009Ultra- sound in Medicine Biology2009,35,11:1
12Treating Arteries Instead of Risk Factors: A Paradigm Change in Management of Atherosclerosis显示文摘J. David Spence Daniel G. Hackam 2010Stroke2010,,6:1
13Carotid plaque measurement is superior to IMT显示文摘J. David Spence 2011Atherosclerosis2011,,1:1
14Toward a better understanding of the etiology of left ventricular dysfunction after mitral valve replacement:an experimental study with possible clinical implications显示文摘Spence PA Peniston CM David TE 1986Ann Thorac Surg1986,41,4:1
15Large Cell Neuroendocrine Carcinoma of the Larynx: Definition of an Entity显示文摘James S. Lewis David C. Spence Simon Chiosea E. Leon Barnes Margaret Brandwein-Gensler Samir K. El-Mofty 2010Head and Neck Pathology2010,,3:1
16Sex Differences in Carotid Plaque and Stenosis显示文摘Francesco Iemolo Alexandra Martiniuk David A. Steinman J. David Spence 2004Stroke: Journal of the American Heart Association2004,,2:1
17Performance analysis of a feasible air-cycle refrigeration system for road transport 显示文摘Stephen W T Spence W John Doran David Wart 2005International Journal of Refrigeration2005,,28:1
18Toward a better understanding of the etiology of left ventricular dysfunction after mitral valve replacement:an experimental study with possible clinical implications显示文摘Spence PA Peniston CM David TE 0,,04:1
19Ultrasound measurement of carotid plaque as a surrogate outcome for coronary artery disease显示文摘David Spence J 2002Am J Cardiol2002,,:1
20Nutrition and stroke prevention显示文摘Mare F Kennedy Lees David Spence J 2006Stroke2006,37,:1
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