PubMed Health⌕ Search

Biomedical subjects

G S Venables

Publications and source records attributed to G S Venables.

At least 19 recordsLinked to original sources
PubMed2005

Safety of arch aortography for assessment of carotid arteries.

PURPOSE: To retrospectively review the safety of arch aortography and compare complication rates with published figures for selective catheter angiography. METHODS: The medical records of patients undergoing arch aortography over the last 3 years (n=311; 180 male, 131 female; mean+/-SD age 71.0+/-9.2 years, range 42-90 years) were retrospectively reviewed. Any peri-procedural (0-48 h) complications were recorded. A certified neurologist (MSR/GSV) classified all questionable neurological events. RESULTS: There were no focal neurological events or deaths (n=0; 0%; CI: 0-0.96%). Non-focal neurological events included mild disorientation (n=2; 0.6%; CI: 0.176-2.31) and unequal pupils (n=1; 0.3%; CI: 0.056-1.79%). Cardiovascular events included symptomatic hypotension (n=4; 1.3%; CI: 0.50-3.25%), angina (n=1; 0.3%; CI: 0.056-1.79%) and arrhythmia (n=4; 1.3%; CI: 0.50-3.25). There were 27 minor access site complications (8.7%; CI: 6.0-12.3). None of these complications extended hospital stay. None of the arch angiograms had to be followed by selective carotid angiography. CONCLUSION: Arch aortography appears to have a lower neurological complication rate than selective carotid angiography.

Adult↗
PubMed2005

Imaging findings and referral outcomes of rapid assessment stroke clinics.

AIM: A rapid assessment stroke clinic (RASC) was established to provide a rapid diagnostic service to individuals with suspected transient cerebral or ocular ischaemia or recovered non-hospitalized strokes. In this report we review imaging findings and clinical outcomes of patients proceeding to the carotid surgery programme. METHODS: Between October 2000 and December 2002, 1339 people attended the RASC. The findings of head CT and carotid Doppler ultrasound of the 1320 patients who underwent brain and carotid imaging were reviewed, and the number subsequently proceeding to carotid angiography and intervention was reported. RESULTS: CT head scans were normal in 57% of cases; 38% demonstrated ischaemia or infarction; and 3% yielded incidental or other significant findings not related to ischaemia. On screening with carotid Doppler ultrasound, 7.5% showed greater than 50% stenosis on the symptomatic side. A total of 83 patients (6.2%) proceeded to cerebral angiography and 65 (4.8%) underwent carotid endarterectomy or endovascular repair. CONCLUSION: Rapid-access neurovascular clinics are efficient in selecting patients for carotid intervention, but this is at a cost and the number of potential strokes prevented is small. Alternative management pathways based on immediate medical treatment need to be evaluated.

Adult↗
PubMed2005

Management of the near total internal carotid artery occlusion.

OBJECTIVES: The risk of stroke in patients with near total internal carotid artery (ICA) occlusion is perceived to be high as stroke risk increases with severity of the stenosis. The management of this entity has not been addressed specifically in the existing randomised trials and thus it remains controversial. METHODS: Systematic review of the relevant literature. RESULTS: The management of patients with near total ICA occlusion remains controversial: some favour intervention whereas others have condemned it as dangerous or of no benefit. A prospective multicentre randomised trial regarding intervention versus best medical treatment for patients with symptomatic near total ICA occlusion seems difficult because of the large number of patients required to power the study. Nevertheless, it appears hard to decline surgery based on the current evidence. CONCLUSIONS: Because of the current controversy over the best management of the near total ICA occlusion, prospective observational studies are needed to demonstrate its prevalence in the symptomatic and asymptomatic population and any associated excess stroke risk. Based on the current evidence, surgery is the treatment of choice in most centres but its validity over best medical treatment remains untested.

Carotid Artery, Internal↗
PubMed2005

The benefits of combined anti-platelet treatment in carotid artery stenting.

OBJECTIVE: To assess the benefits of a combined anti-platelet regime of aspirin and clopidogrel in carotid artery stenting. METHODS: A randomised controlled trial was performed comparing aspirin and 24-h heparin with aspirin and clopidogrel for patients undergoing carotid artery stenting. Outcome measures included 30-day bleeding and neurological complications and 30-day stenosis rates. RESULTS: Bleeding complications (groin haematoma or excessive bleeding at the groin site) occurred in 17% of the heparin and 9% of the clopidogrel group (p=0.35; n.s). The neurological complication rate in the 24-h heparin group was 25% compared to 0% in the clopidogrel group (p=0.02). The 30-day 50-100% stenosis rates were 26% in the heparin group and 5% in the clopidogrel group (p=0.10; n.s). CONCLUSIONS: The dual anti-platelet regime has a significant impact on reducing adverse neurological outcomes without an additional increase in bleeding complications. This study was terminated prematurely due to an unacceptable level of complications in the heparin arm of the trial.

Aged↗
PubMed2004

Is the endovascular treatment of carotid stenosis in high-risk patients really safer than carotid endarterectomy?

BACKGROUND: We assess the outcomes of patients who would have been considered at high-risk from carotid endarterectomy (CEA), who have undergone endovascular treatment. METHODS: High-risk patients were classed as those with occlusion of the contralateral internal carotid artery, recurrent stenosis following CEA, stenosis secondary to neck irradiation or treatment prior to coronary bypass surgery. RESULTS: 103 procedures fulfilled at least one inclusion criterion. 58.3% had symptomatic disease. The all stroke/death rate was 9.7%. The major disabling stroke/stroke-related death rate was 3.9%. 63 had a contralateral occlusion, 15 post-CEA, 17 post-radiation and 33 pre-coronary surgery. The major disabling stroke/stroke-related death rates for each subset were 4.8, 6.7, 0 and 0%, respectively. CONCLUSIONS: These results suggest that this category of patients is at high-risk of stroke regardless of method of carotid intervention.

Adult↗
PubMed2003

Effect of treatment of carotid artery stenosis on blood pressure: a comparison of hemodynamic disturbances after carotid endarterectomy and endovascular treatment.

BACKGROUND AND PURPOSE: Carotid intervention by carotid endarterectomy (CEA) or endovascular treatment may cause hemodynamic change. The immediate and long-term effects on blood pressure after these procedures were assessed. METHODS: Patients were randomized to CEA (n=49) or endovascular treatment (n=55) that comprised percutaneous transluminal angioplasty alone (n=31), balloon-expandable stent (n=13), or self-expandable stent (n=11). A baseline 24-hour ambulatory blood pressure recording was made before carotid intervention and repeated at 24 hours, 1 month, and 6 months after the procedure. RESULTS: In the first 24 hours after the procedure, episodes of hypotension occurred in 75% of the CEA group and 76% of the endovascular group; hypertension occurred in 11% and 13%, respectively. There was a significant fall in blood pressure at 1 hour after the procedure in both groups (24 and 16 mm Hg fall in CEA and endovascular groups, respectively), but this was only sustained in the endovascular group. The pattern of blood pressure response in the first 24 hours was significantly different (P<0.0001, ANCOVA). Systolic blood pressure was significantly lower at 1 and 6 months only in the surgical group (6 and 5 mm Hg fall, respectively). CONCLUSIONS: Both CEA and endovascular treatment have an effect on blood pressure stability, particularly within the first 24 hours after the procedure.

Aged↗
PubMed2003

Complications following carotid angioplasty and carotid stenting in patients with symptomatic carotid artery disease.

BACKGROUND: We review a single centre's experience of the endovascular treatment of carotid artery disease, present the 30-day and 1-year complication rates and assess whether changes in technique are associated with a change in clinical outcome. METHODS: Patients who underwent carotid angioplasty with or without stenting for symptomatic > or = 70% carotid artery stenosis secondary to atherosclerosis were included. 333 procedures were performed, i.e. angioplasty alone (86), stent without cerebral protection (150) and stent with cerebral protection (97). RESULTS: At 30 days, the total major disabling stroke and all death rate was 3.0%. For angioplasty alone, this was 2.3%, for stent without cerebral protection 4.0% and for stent with cerebral protection 2.1%. If non-stroke-related deaths were excluded, it was 2.3, 3.3 and 0%, respectively. After 30 days, the 1-year ipsilateral stroke rate was 0.8%. CONCLUSIONS: Carotid artery stenting, in particular with a cerebral protection device, is a safe alternative to carotid endarterectomy for the treatment of symptomatic high-grade carotid artery disease.

Aged↗
PubMed2003

Acute stroke treatment in Europe: a questionnaire-based survey on behalf of the EFNS Task Force on acute neurological stroke care.

In 1997 the EFNS Task Force on Acute Neurological Stroke Care published its recommendations for acute stroke care (Brainin et al., 1997), which, in 1999, was followed by a stroke care inventory (Brainin et al., 2000) assessing the development of acute stroke care. In 2000 all 33 members of the EFNS Stroke Scientist Panel were asked to complete a questionnaire on the treatment of acute stroke in their country as of 2000. Data were based either on national surveys or a personal estimate of national practice, together with data from the personal practice of the panel member. Data from 22 countries were received. One of the principal findings is the lack of systematic evidence about practice in a significant number of European countries. Results illustrate that neurologists have a leading role in implementing acute stroke treatment guidelines and in adopting new therapeutic methods in most countries, but there is a wide variation in the application of different therapeutic procedures.

Advisory Committees↗
PubMed2000

Comparison of Doppler ultrasound, magnetic resonance angiographic techniques and catheter angiography in evaluation of carotid stenosis.

AIM: To compare the accuracy of ultrasound and two magnetic resonance (MR) angiographic techniques with catheter angiography in assessing atherosclerosis at the carotid bifurcation. MATERIALS AND METHODS: Forty patients with symptomatic carotid stenosis were studied by Doppler ultrasound, time-of-flight MR angiography, contrast-enhanced MR angiography and conventional catheter angiography. The degree of stenosis found on ultrasound and MR angiography was compared with the results of catheter angiography. Four different assessment methods were conducted for the MR angiographic data. Kappa, sensitivity and specificity (with confidence intervals) values were calculated for the US and MR angiography results compared to catheter angiography. RESULTS: Catheter angiography showed 12 internal carotid artery occlusions (15%), 34 severe (44%), 12 moderate (15%) and 20 mild stenoses (26%), using NASCET criteria. Ultrasound showed 65% sensitivity and 95% specificity in detecting surgically amenable lesions, whilst the MR angiographic techniques had sensitivities varying from 82-100%, and specificities from 95-100%.A moderate kappa value was calculated for the US data, whilst all MR techniques were found to show very good agreement with catheter angiography. CONCLUSION: This data suggests that MR angiography is more accurate than Doppler ultrasound in defining surgical lesions and has comparable accuracy to catheter angiography. The use of contrast-enhanced MR angiography is useful in certain situations but is not essential in all cases.

Aged↗
PubMed2000

Unilateral leptomeningeal enhancement after carotid stent insertion detected by magnetic resonance imaging.

BACKGROUND AND PURPOSE: Percutaneous transluminal angioplasty combined with vascular stenting is currently being assessed in the treatment of patients with symptomatic, severe carotid stenosis. The immediate cerebral hemodynamic effects resulting from stenting are not fully understood. This article describes a novel finding: abnormal leptomeningeal enhancement after stenting shown by MRI. METHODS: Fourteen patients with symptomatic severe carotid bifurcation stenosis underwent MRI within 4 hours before and within 3 hours after attempted carotid stenting. Twelve patients were successfully stented. Part of the MR investigation consisted of the acquisition of T1-weighted images before and after administration of the contrast agent Gd-DTPA, both before and after the procedure. RESULTS: All 12 patients who underwent successful stenting did not have abnormal enhancement of the leptomeninges before stenting but developed unilateral enhancement following intervention but before the second injection of contrast agent. No contrast enhancement was detected in the 2 patients who had the angiographic procedure but were not stented. CONCLUSIONS: These findings suggest that abnormal changes to the leptomeningeal vasculature occur during carotid stenting which are not associated with sudden development of neurological symptoms. The anatomic distribution of the enhancement suggests that it is a consequence of the sudden change in brain hemodynamics secondary to the improvement in carotid flow after stenting.

Aged↗
PubMed2000

Anticoagulants.

Anticoagulation is a treatment with significant and life threatening complications requiring that the balance of risk and benefit be individually assessed in each patient. The risks are greater in the elderly and those with hypertension, falls and gastrointestinal disease. The use of anticoagulants is now established in patients with symptomatic non-rheumatic atrial fibrillation, especially older patients with hypertension, cardiac failure or a large left atrium or left ventricular dysfunction. There is, however, no place for the routine use of anticoagulants in acute stroke or as part of secondary prevention in patients in sinus rhythm. There may be a place, though as yet the evidence would not support this, for the limited use of anticoagulants in special situations such as cortical venous thrombosis or carotid dissection.

Anticoagulants↗
PubMed1998

Diagnosis and management of transient ischaemic attacks in accident and emergency.

Stroke is an important cause of morbidity and mortality. Often the first presentation of cerebrovascular disease is a TIA which will present to the A&E department. Patients who have had a TIA are at increased risk of stroke, myocardial infarction, and vascular death. The risk of stroke after a TIA is greatest in the first year (approximately 11.6%) with a risk of approximately 5.9% per year over the first five years. As the risk is highest in the first months following a TIA it is important that the patients are diagnosed accurately, investigated promptly, and referred appropriately for treatment in order that valuable time is not lost. For this reason A&E physicians have a valuable role in the initial assessment and management of the patient. It has been advocated that patients should be seen by a neurologist or physician with an interest in cerebrovascular disease within days of their symptoms and be prepared for surgery within two weeks after a TIA. While it is usually not possible to achieve this ideal, improved cooperation between A&E physicians and these neurologists, general physicians, and geriatricians should lead to the implementation of speedy efficient referral procedures which can only improve patient care. When you next see a patient with a TIA in the A&E department remember what they have to lose. Three questions relating to this article are: (1) How are TIAs subdivided and what clinical features allow this differentation? (2) What are the initial investigations that should be performed in A&E? (3) When are the risks of completed stroke greatest after a TIA? Enumerate these risks. How effective is aspirin at reducting this risks?

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Multifocal motor neuropathy.

We present a review of the literature on multifocal motor neuropathy (MMN), a rare neurological disorder which has features in common with both chronic inflammatory demyelinating neuropathy and lower motor neuron disease. Clinically, MMN is characterised by slowly progressive asymmetrical limb weakness, usually most prominent in the forearms. Weakness may be associated with muscle wasting, fasciculations and decreased tendon reflexes. Serum anti-GM1 ganglioside antibody titres may be increased. The diagnostic hallmark of MMN is the electrophysiological demonstration of persistent localised motor conduction blocks, with otherwise normal or near-normal motor and sensory conduction velocities. The pathogenesis of MMN has not been elucidated completely. There is, however, substantial evidence for an autoimmune mechanism. Based on the possible involvement of the immune system in the pathogenesis of MMN the therapeutic efficacy of several immunomodulatory drugs has been tested. Treatment of MMN patients with human immunoglobulin or cyclophosphamide is usually followed by a marked improvement of strength. The finding that MMN is a potentially treatable disorder underscores the importance of distinguishing MMN from lower motor neuron disease, for which no effective therapy is currently available.

Biopsy↗
PubMed1996

European carotid angioplasty trial.

The Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS) is an international multicenter randomized trial, the primary aims of which are: (1) to determine the risks and benefits of carotid and vertebral artery transluminal angioplasty; and (2) to compare these with surgical treatment (carotid endarterectomy) or best medical treatment. Through the end of October 1995, 193 patients have been randomized (90 at our center). In this article, the rationale for the trial, its design and protocol, and the experience of our institution within the trial will be discussed.

Angioplasty, Balloon↗
PubMed1995

Predictors of major vascular events in patients with a transient ischemic attack or minor ischemic stroke and with nonrheumatic atrial fibrillation. European Atrial Fibrillation Trial (EAFT) Study Group.

BACKGROUND AND PURPOSE: The risk of major vascular events after an initial episode of cerebral ischemia in patients with nonrheumatic atrial fibrillation (NRAF) varies from 2% to 15% in the first year and is approximately 5% yearly thereafter. Few studies have reported on risk factors that can be used to identify high-risk subgroups within this patient population. METHODS: We studied the predictive value of several easily obtainable clinical characteristics in a group of 375 placebo-treated patients with NRAF and a recent episode of transient or nondisabling cerebral ischemia who were entered in a multicenter clinical trial. The mean follow-up was 1.6 years. RESULTS: By means of multivariate modeling, six independent variables were identified: history of previous thromboembolism, ischemic heart disease, enlarged cardiothoracic ratio on chest roentgenogram, systolic blood pressure greater than 160 mm Hg at study entry, NRAF for more than 1 year, and presence of an ischemic lesion on CT scan. These variables could also be used to stratify patients in low-, medium-, and high-risk subgroups for the other two arms of the trial, those treated with anticoagulation and aspirin. Patients older than 75 years with three or more risk factors seemingly benefited less from both aspirin and anticoagulant treatment. CONCLUSIONS: Easily obtainable patient characteristics are helpful in estimating the potential effect of adequate secondary prevention in patients with NRAF who recently suffered a transient ischemic attack or minor ischemic stroke.

Aged↗
PubMed1991

The role of magnetic stimulation in the diagnosis of multiple sclerosis.

Magnetic stimulation was used to measure motor conduction time (MCT) between head and neck, and head and lumbar region, as well as amplitude of the motor evoked potential (MEP) in normal subjects and patients with multiple sclerosis (MS). Patients with definite MS had significantly longer MCTs and smaller amplitude MEPs than normal subjects when recording from arm and leg muscles. In a comparison with visual evoked potential (VEP) recordings, head to neck MCTs were abnormal less often than VEPs, and VEPs detected more silent lesions. Recording from leg as well as arm muscles significantly increased the yield of abnormal MCT measurements. The detection of silent lesions in the patients with definite MS was improved, but there was no improvement in the non-definite cases. Amplitude measurements provided very little extra diagnostic information over MCT measurements alone and did not improve the detection of silent lesions. Interside MCT differences yielded extra abnormalities when recording from the arms but not the legs. Interside MCT abnormalities increased the detection of silent lesions in both the definite and non-definite categories. It was concluded that the majority of useful diagnostic information in patients with MS should be obtainable from bilateral MCT (head to neck) measurements, together with estimation of interside MCT differences. However, VEP recording is a better diagnostic test for MS than MEP recording as more silent lesions are detected. This may be because MCT abnormalities tend to reflect the degree of pyramidal disability.

Adult↗
PubMed1991

The role of magnetic stimulation as a quantifier of motor disability in patients with multiple sclerosis.

Magnetic stimulation was used to measure motor conduction time (MCT) between head and neck in a prospective longitudinal study of patients with multiple sclerosis (MS) and normal subjects. MCT measurements showed a high degree of reproducibility in normal subjects and patients with stable MS. In patients with definite MS, there was significant positive correlation between MCT and motor disability. In patients treated with steroids for relapse of MS, there was significant shortening of MCT following treatment in those who clinically improved, but not in those who were clinically unchanged. In a smaller group of patients followed for 3 months, MCT changes tended to mirror the clinical pattern. Magnetic stimulation should prove a useful tool for the quantification of motor disability, and monitoring the response to new treatments in MS.

Adrenal Cortex Hormones↗