Abstract 67: Importance Of Previous Brain Infarcts In Patients With Asymptomatic Carotid Stenosis And The Impact Of Surgery From The Asymptomatic Carotid Surgery Trial-1

Background and aims: Silent brain infarcts are common in patients at increased risk of stroke and are associated with a poor prognosis. Similar adverse associations were claimed in asymptomatic carotid stenosis (ASCS) patients but the impact of previous infarction or symptoms on the beneficial effects of carotid endarterectomy (CEA) is not clear. Our aim was to evaluate the importance of prior brain infarcts (PBI) in ASCS patients enrolled in ACST-1 - a large trial with 10-year follow-up.

Methods: Of 3120 patients included in ACST-1, 787 patients without baseline imaging were excluded. Trial patients (2333) with brain imaging at trial entry were identified & divided into those with PBI (i.e. radiological evidence of an asymptomatic infarct or prior ischaemic symptoms [PIS] >6 months prior to randomization) (group 1, 1331 patients) & those with normal imaging and no PIS (group 2, 1002 patients). The trial allocated immediate CEA treatment to about half of the patients in both groups. First stroke and vascular death in these groups were compared during follow-up irrespective of treatment assignment and, for both groups, the impact of CEA was analyzed.

Results: Baseline characteristics of excluded & analyzed patients were similar, male gender and hypertension being commoner in group 1 with slightly tighter ipsilateral stenosis in group 2. After 10 years stroke was significantly commoner in group 1 (absolute risk increase [ARI] 5.8% [1.8-9.8], p=0.004) as was risk of stroke and vascular death (6.9% [1.9-12.0] ARI, p=0.007). Multivariate analysis confirmed that PBI was associated with greater risk of stroke (HR=1.51 95%CI:1.17-1.95) and of any stroke or other vascular death (HR=1.30 95%CI:1.11-1.52). Benefits of CEA at 5 years appeared greater for group 1 patients (gain 4.9% p=0.005%) than for group 2 (gain at 5 years, 3.9% p=0.02%) though it must be emphasized that the trial was not designed to test this comparison.

Conclusions: ASCS patients with prior brain infarcts have higher stroke risk during long-term follow-up than those without PBI and may benefit more from CEA.

Asymptomatic carotid disease and cardiac surgery consensus

The Carotid Disease and Cardiac Surgery Consensus Meeting was convened as a multidisciplinary gathering to consider the management of patients undergoing cardiac surgery who are found to have asymptomatic carotid artery disease. There are no randomized trials concerning whether carotid interventions are of value in this situation and the natural history is unclear. Bilateral carotid artery disease (≥70% stenosis) should be regarded clinically relevant when considering hemodynamic and short-term surgical stroke risk. However, this may be because the presence of significant carotid disease is also a marker for aortic arch and intracerebral disease. A natural history study is urgently needed to determine the incidence, predictive factors, and natural history of asymptomatic carotid disease in patients undergoing contemporary cardiac surgical interventions to inform the design of any future randomized trial.

Controversies in neurology: asymptomatic carotid stenosis--intervention or just stick to medical therapy. The argument for carotid endarterectomy

Patients with a significant carotid stenosis are at an increased risk of suffering from a potentially fatal or disabling stroke. The current management strategies available to a patient with an asymptomatic carotid stenosis are either medical therapy alone, or in combination with either carotid endarterectomy, or carotid angioplasty and stenting. Medical therapy alone can reduce the incidence of stroke in general, but whether there is any reduction in stroke attributable to a significant carotid stenosis is less clear. Carotid endarterectomy, on the other hand, has been shown to reduce the incidence of ipsilateral ischaemic stroke in both symptomatic and asymptomatic patients, with the benefits extending into the long-term. Carotid angioplasty and stenting is a newer technique with the benefit of being minimally invasive. The results of trials comparing the technique to endarterectomy have had conflicting results, and the results of large multi-centre trials are awaited. Currently the safest strategy for a patient with a significant asymptomatic carotid stenosis consists of optimal medical therapy with carotid endarterectomy for those less than 75 years of age, who are suitable for surgery.

10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1): a multicentre randomised trial

BACKGROUND

If carotid artery narrowing remains asymptomatic (ie, has caused no recent stroke or other neurological symptoms), successful carotid endarterectomy (CEA) reduces stroke incidence for some years. We assessed the long-term effects of successful CEA.

METHODS

Between 1993 and 2003, 3120 asymptomatic patients from 126 centres in 30 countries were allocated equally, by blinded minimised randomisation, to immediate CEA (median delay 1 month, IQR 0·3-2·5) or to indefinite deferral of any carotid procedure, and were followed up until death or for a median among survivors of 9 years (IQR 6-11). The primary outcomes were perioperative mortality and morbidity (death or stroke within 30 days) and non-perioperative stroke. Kaplan-Meier percentages and logrank p values are from intention-to-treat analyses. This study is registered, number ISRCTN26156392.

FINDINGS

1560 patients were allocated immediate CEA versus 1560 allocated deferral of any carotid procedure. The proportions operated on while still asymptomatic were 89·7% versus 4·8% at 1 year (and 92·1%vs 16·5% at 5 years). Perioperative risk of stroke or death within 30 days was 3·0% (95% CI 2·4-3·9; 26 non-disabling strokes plus 34 disabling or fatal perioperative events in 1979 CEAs). Excluding perioperative events and non-stroke mortality, stroke risks (immediate vs deferred CEA) were 4·1% versus 10·0% at 5 years (gain 5·9%, 95% CI 4·0-7·8) and 10·8% versus 16·9% at 10 years (gain 6·1%, 2·7-9·4); ratio of stroke incidence rates 0·54, 95% CI 0·43-0·68, p<0·0001. 62 versus 104 had a disabling or fatal stroke, and 37 versus 84 others had a non-disabling stroke. Combining perioperative events and strokes, net risks were 6·9% versus 10·9% at 5 years (gain 4·1%, 2·0-6·2) and 13·4% versus 17·9% at 10 years (gain 4·6%, 1·2-7·9). Medication was similar in both groups; throughout the study, most were on antithrombotic and antihypertensive therapy. Net benefits were significant both for those on lipid-lowering therapy and for those not, and both for men and for women up to 75 years of age at entry (although not for older patients).

INTERPRETATION

Successful CEA for asymptomatic patients younger than 75 years of age reduces 10-year stroke risks. Half this reduction is in disabling or fatal strokes. Net benefit in future patients will depend on their risks from unoperated carotid lesions (which will be reduced by medication), on future surgical risks (which might differ from those in trials), and on whether life expectancy exceeds 10 years.

FUNDING

UK Medical Research Council, BUPA Foundation, Stroke Association.

Characterisation of progenitor cells in human atherosclerotic vessels

Recent data from animal models has demonstrated that both endothelial and smooth muscle progenitor cells contribute to the development of atherosclerosis. However, no data exists concerning the presence of progenitor cells in human atherosclerotic vessels. In the present study, a range of normal and atherosclerotic human arteries were collected from patients undergoing coronary artery bypass surgery. Segments of internal mammary artery (normal controls), and segments of proximal ascending aorta with visible fatty streak were analysed. Immunofluorescence was used to detect a panel of progenitor cell markers. A small number of progenitor cells were identified within neointimal lesions and the adventitia with variable expression of CD34, stem cell antigen (Sca-1), c-kit and VEGF receptor 2 (VEGFR2) markers, but no CD133 expression. On average there was a two- to three-fold increase in progenitor cell number in the adventitia of atherosclerotic vessels compared with normal controls, with a significant difference (p<0.05) in the frequency of cells expressing VEGFR2. Thus, we have provided the first evidence that vascular progenitor cells exist within atherosclerotic lesions, and identified an increased number of progenitor cells in the adventitia of human atherosclerotic vessels. These cells might be a source for smooth muscle cells (SMCs), macrophages and endothelial cells (ECs) that form atherosclerotic lesions.

The prevalence of thrombophilia in patients with symptomatic peripheral vascular disease

Background

The aim of this prospective study was to establish the prevalence of thrombophilia and hyperhomocysteinaemia using a comprehensive screen in patients with peripheral vascular disease.

Methods

A total of 150 patients with peripheral vascular disease (with an ankle brachial pressure index of less than 0·8) underwent thrombophilia screening (protein C and protein S, antithrombin, lupus anticoagulant, activated protein C resistance and factor V Leiden and prothrombin mutations). Fasting homocysteine assays were also performed.

Results

A thrombophilia defect was found in 41 patients (27·3 per cent). The commonest was protein S deficiency, found in 17 patients (11·3 per cent). Others included factor V Leiden mutation, found in 10 (6·7 per cent) and protein C deficiency, found in six (4·0 per cent). Lupus anticoagulant and prothrombin mutation were both found in six (4·0 per cent). One patient had an antithrombin deficiency. Only the presence of critical ischaemia was associated with a positive thrombophilia screen on single variable analysis (P = 0·03). Hyperhomocysteinaemia was present in over a third of the study group (37·3 per cent): 45 defined as moderate and 11 as intermediate.

Conclusion

A quarter of patients with peripheral vascular disease had evidence of thrombophilia, and a third had hyperhomocysteinaemia.

An immunogenic cathepsin F secreted by the parasitic stages of Teladorsagia circumcincta

Teladorsagia circumcincta is a common, pathogenic abomasal nematode of sheep. In order to improve disease control in parasite isolates resistant to several anthelmintics, alternative methods must be sought. Sheep develop acquired immunity to T. circumcincta so vaccination is a valid option for control. For this reason, we are investigating parasite excretory/secretory products for molecules, which have potential to invoke protective immunity against T. circumcincta. Here, we describe experiments in which we identified a novel, immunogenic cathepsin F secreted by L4 T. circumcincta. This protease, initially identified by mass spectrometry analysis, is the most abundant molecule in excretory/secretory products released in vitro by T. circumcincta harvested at 5, 6 or 9 days p.i. and is a target of specific, local IgA responses in sheep which are immune to challenge infection. The full-length cDNA encoding this secreted protease was isolated. Sequence and phylogenetic analyses indicated that the protease (designated T. circumcincta cathepsin F-1, Tci-CF-1) belongs to the cathepsin F class and exhibits greatest identity (>60%) to expressed sequence tags present in the Ostertagia ostertagi and Haemonchus contortus expressed sequence tag databases. Tci-CF-1 also displays high identity to hypothetical proteins identified in the genomes of Caenorhabditis elegans and Caenorhabditis briggsae, both proteins having been described as cathepsin F enzymes. Specific inhibitor binding assay of larval excretory/secretory products confirmed the classification of this excretory/secretory component as a cathepsin F. Reverse transcription-PCR studies indicated that Tci-cf-1 is developmentally regulated and is particular to the host parasitic stages of T. circumcincta. The abundance, immunogenicity and temporal expression pattern of Tci-CF-1 make this a potential vaccine candidate for teladorsagiosis.

Prevalence and Risk of Thrombophilia Defects in Vascular Patients

This paper reviews the available data on the prevalence of thrombophilia defects in patients with peripheral vascular disease (PVD) and attempts to delineate the risk of failure of vascular intervention in these patients. The prevalence of thrombophilia in stable claudicants is 25% and increases to 40% in those requiring revascularisation, compared to only 11% in the control group. The overall prevalence of thrombophilia defects in patients with premature atherosclerosis appears to be between 15 and 30%. The prevalence in the typical cohort of patients with PVD appears to be similar. All these studies have recruited patients with symptoms significant enough to warrant intervention. The overall prevalence of thrombophilia calculated from these trials, therefore, may not be truly indicative of the general vascular population who may not even present primary or secondary healthcare. The risk of thrombotic occlusion following arterial revascularisation in patients with an identified thrombophilia defect appears to be almost three times that of patients with no evidence of a thrombophilia defect. The best management of these patients has not been determined and needs to be evaluated by prospective randomized trials.

Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial

BACKGROUND

Among patients with substantial carotid artery narrowing but no recent neurological symptom (stroke or transient ischaemia), the balance of surgical risks and long-term benefits from carotid endarterectomy (CEA) was unclear.

METHODS

During 1993-2003, 3120 asymptomatic patients with substantial carotid narrowing were randomised equally between immediate CEA (half got CEA by 1 month, 88% by 1 year) and indefinite deferral of any CEA (only 4% per year got CEA) and were followed for up to 5 years (mean 3.4 years). Kaplan-Meier analyses of 5-year risks are by allocated treatment.

FINDINGS

The risk of stroke or death within 30 days of CEA was 3.1% (95% CI 2.3-4.1). Comparing all patients allocated immediate CEA versus all allocated deferral, but excluding such perioperative events, the 5-year stroke risks were 3.8% versus 11% (gain 7.2% [95% CI 5.0-9.4], p<0.0001). This gain chiefly involved carotid territory ischaemic strokes (2.7% vs 9.5%; gain 6.8% [4.8-8.8], p<0.0001), of which half were disabling or fatal (1.6% vs 5.3%; gain 3.7% [2.1-5.2], p<0.0001), as were half the perioperative strokes. Combining the perioperative events and the non-perioperative strokes, net 5-year risks were 6.4% versus 11.8% for all strokes (net gain 5.4% [3.0-7.8], p<0.0001), 3.5% versus 6.1% for fatal or disabling strokes (net gain 2.5% [0.8-4.3], p=0.004), and 2.1% versus 4.2% just for fatal strokes (net gain 2.1% [0.6-3.6], p=0.006). Subgroup-specific analyses found no significant heterogeneity in the perioperative hazards or (apart from the importance of cholesterol) in the long-term postoperative benefits. These benefits were separately significant for males and females; for those with about 70%, 80%, and 90% carotid artery narrowing on ultrasound; and for those younger than 65 and 65-74 years of age (though not for older patients, half of whom die within 5 years from unrelated causes). Full compliance with allocation to immediate CEA or deferral would, in expectation, have produced slightly bigger differences in the numbers operated on, and hence in the net 5-year benefits. The 10-year benefits are not yet known.

INTERPRETATION

In asymptomatic patients younger than 75 years of age with carotid diameter reduction about 70% or more on ultrasound (many of whom were on aspirin, antihypertensive, and, in recent years, statin therapy), immediate CEA halved the net 5-year stroke risk from about 12% to about 6% (including the 3% perioperative hazard). Half this 5-year benefit involved disabling or fatal strokes. But, outside trials, inappropriate selection of patients or poor surgery could obviate such benefits.

Poor outcome following revascularization predicted by thromboelastography

Background

Infrainguinal revascularization procedures are associated with a high risk of graft failure, amputation and early death. Hypercoagulability predicts a poor overall outcome but conventional tests are expensive and results are not immediately available. A cheap, rapid method for identifying hypercoagulability would allow screening before revascularization. Thromboelastography (TEG) is a rapid, reliable, bedside method of assessing whole blood clotting. Normally used to assess hypocoagulability, this study determined the role of TEG in identifying patients with a poor prognosis following revascularization.

Methods

Between November 1998 and January 2000, 106 patients with critical leg ischaemia were admitted for radiological or surgical revascularization (mean age 71 (range 33–90) years). All underwent TEG analysis, standard thrombophilia screening (STS), and fasting homocysteine and fibrinogen assays. All patients were followed for 6 months after revascularization by means of clinical examination, ankle: brachial pressure index (ABPI) and duplex imaging.

Results

At the 6-month follow-up of 106 patients, 29 (27 per cent) had arterial or graft occlusion, five (5 per cent) had died and four (4 per cent) had undergone a major amputation. Analysis of risk factors revealed that a hypercoagulable TEG (P = 0·0009), STS and/or raised fibrinogen level (P = 0·01), and rest pain (P = 0·006) were associated with poor outcome. Other factors such as age, sex, diabetes, current or previous smoking, coronary artery or cerebrovascular disease, hypertension, previous intervention, aspirin or lipid-lowering therapy were not significantly different. In addition, hyperlipidaemia, hyperhomocysteinaemia, raised level of C-reactive protein, eyrthrocyte sedimentation rate, lipoprotein a level, haemocrit, STS or fibrinogen alone were not useful as predictors of poor outcome.

Conclusion

TEG, a rapid inexpensive test of hypercoagulability, is associated with poor outcome following infrainguinal revascularization.

Simultaneous ultratrace determination of Zr and Nb in chromium matrixes with ICP-dynamic reaction cell MS

A dynamic reaction cell (DRC) has been used to minimize the formation of metal-argide ions in inductively coupled plasma mass spectrometry and applied to the determination of Zr and Nb in Cr-rich samples. The formation of ArCr+ species from the plasma gas and the sample matrix was reduced by ion molecule reactions inside a DRC of the ICPMS used. Hydrogen was used as reaction gas, and the efficiency in the reduction of ArCr+ was similar to that of other plasma-based polyatomic ions as reported in an earlier study. The formation of CrOx+ ions is enhanced when the DRC is operated in pressurized mode. Adjustment of the transmission properties of the band-pass quadrupole to reject precursor ions can be achieved without dramatic decrease of sensitivity but with a significant improvement in the signal/background ratio. Measurements in solutions containing concentrations of up to 2 g/L Cr showed that the determination of Nb and Zr is possible in the nanogram per liter range in such a matrix. The limits of detection for Nb and Zr in pure Cr metal have been estimated at 2 ng/g for Nb and 5 ng/g for Zr. Analysis of basaltic reference samples resulted in very good agreement with previously published data.

Thromboelastography: a reliable test?

The thromboelastograph (TEG), a measure of global haemostasis, is routinely used during cardiac and hepatic surgery to optimize blood product selection and usage. It has recently been suggested that it may also be a useful tool to screen patients with hypercoagulable states. Limited published data on performance characteristics has led to speculation regarding its consistency and, therefore, validity of the results. This study was designed to assess the effect of stability of blood samples prior to testing, repeated sampling, intra- and inter-assay variability using the native, celite, tissue factor (TF) and Reopro-modified TEG. Analysis of native and celite samples after storage over 90 min showed a period of instability up to 30 min. Thereafter, all parameters between 30 and 90 min were stable [P = not significant (NS)]. When the same sample was repeatedly assayed, both native and celite TEG parameters showed a significant change towards hypercoagulability (P < 0.01), whereas the TF and Reopro-modified TEG showed no change. Intra- and inter-assay variability on samples tested after 30 min showed excellent reproducibility for all parameters (P = NS). The data suggest that the TEG is a useful tool in haemostasis but requires a formal standard operating procedure to be adopted that takes into account the initial period of sample instability.

Thromboelastography

The Thromboelastograph has now been in use for over 50 years and has been largely regarded as a research tool. Increasing automation and refinement of the TEG and standardisation of results has led to decreased speculation regarding its validity as an assay of haemostasis. There are increasing clinical applications including cardiothoracic surgery and liver transplantation. This review discusses the principles and limitations of the TEG. It also focuses on the current clinical applications and potential research interests.

Carotid endarterectomy: indications for symptomatic and asymptomatic stenosis

There have been several clinical trials pertaining to carotid endarterectomy in the last two decades. These studies have provided long-awaited information regarding the risks and benefits of surgery for carotid stenosis. This paper outlines the key results for patients with symptomatic and asymptomatic stenosis. A scheme for the identification of patients likely to benefit from surgery, and persistent areas of controversy and uncertainty, are reviewed.

Vascular surgical society of great britain and ireland: carotid angiography is used more selectively in the asymptomatic carotid surgery trial

BACKGROUND: The ongoing Asymptomatic Carotid Surgery Trial (ACST) has randomized more than 1900 patients to determine whether carotid endarterectomy prolongs stroke-free survival compared with best medical treatment alone. Previously the Asymptomatic Carotid Atherosclerosis Study demonstrated that preoperative angiography caused stroke or death in 1 per cent of patients, and many centres have now reduced or abandoned this practice. This study determined the changing practice of carotid angiography in the ACST. METHODS: Collaborating surgeons completed questionnaires annually on their use and method of angiography. Information on patients in the ACST who had angiography at randomization was also obtained. RESULTS: In 1993, 77 per cent of responding collaborators always performed preoperative angiography and 23 per cent used angiography selectively. This trend has reversed: by 1997, 26 per cent always used preoperative angiography, 70 per cent of respondents used preoperative angiography selectively and 4 per cent had abandoned angiography (P < 0.001, chi2 for trend). Information on carotid angiography at randomization has to date been obtained on 1141 patients in the ACST. Some 44 per cent (497 of 1141) had carotid angiography at randomization. Surgical patients had angiography more commonly than those in the medical group (49 versus 42 per cent; P < 0.03, chi2 test). Changes in carotid angiography were analysed by year of randomization. In 1993, 61 per cent of patients randomized had carotid angiography compared with 42 per cent in 1996 and 1997 (P < 0.001, chi2 for trend). The use of carotid angiography was not related to degree of stenosis estimated by Doppler ultrasonography. CONCLUSION: In the ongoing ACST, there is increasingly selective use of carotid angiography. Less than half the patients in this study had carotid angiography and the use of angiography is now decreasing. This has important implications for validation of carotid duplex in this trial and in future studies.

Carotid duplex ultrasonography: importance of standardisation. Asymptomatic Carotid Surgery Trial Collaborators and Vascular Laboratories

BACKGROUND

Carotid duplex ultrasonography (CDUS) is an established non-invasive tool for assessing patients with suspected carotid bifurcation disease. Current trends show an increased dependence on CDUS in recommending patients for stroke prevention surgery. The aim of the study was to evaluate routine practice in vascular laboratories across 26 countries participating in The Asymptomatic Carotid Surgery Trial (ACST), and to determine the areas which are in need of future standardisation if CDUS is to be the primary tool in recommending patients for CEA.

METHODS

Retrospective. Information was gathered from questionnaires, and 22 on-site visits of vascular laboratories between August 1996 to September 1997.

SETTING

Clinical vascular laboratory practice.

PARTICIPANTS

Eligible participants were vascular laboratories of ACST collaborators.

MEASURES

Laboratories were compared in 7 categories: ultrasound equipment, operators, experience, protocols, stenosis evaluation, interpretation criteria, and reporting.

RESULTS

Information on 117 respondents showed that (i) experience: at least one operator in each laboratory had more than 3 years experience; (ii) equipment: 88% (103/117) had colour duplex capability; (iii) operators: 54% of laboratories had exams performed by technologists, 33% vascular surgeons, 28% radiologists, and 35% other. The most significant findings were in (iv) stenosis evaluation: only 29% (33/117) were using a standardised Doppler angle (this single factor may greatly alter exam results); and (v) interpretation criteria; with >41 different criteria reported. These specific laboratory variations can affect those patients considered appropriate for CEA.

CONCLUSIONS

This study highlights the most significant areas for future standardisation to be Doppler angle and interpretation criteria, if CDUS is to be a primary tool in recommending patients for CEA, when indicated by clinical trial results.

Prevalence of asymptomatic CT infarcts in the ongoing Asymptomatic Carotid Surgery Trial (ACST)

BACKGROUND

The ACST has randomised over 1670 patients to determine if carotid endarterectomy (CEA) prolongs stroke free survival when compared with best medical treatment alone. This study aims to assess the prevalence of asymptomatic cerebral infarcts in patients grouped by sex, age, mean blood pressure (MBP), total cholesterol, diabetes and coronary artery disease (CAD).

METHODS

The type of study was retrospective. Patients with preoperative CT scans were included. In those with previous stroke, only the contralateral cerebral hemisphere was studied for presence of infarcts. One thousand one hundred and forty-two patients were studied.

RESULTS

The proportion of patients with CT infarcts was 19% (211/1142). Men (155/777) had a higher incidence of CT infarction (20% vs 15%, p = 0.01). Mean age was 68 years and mean MBP was 107 mmHg. The incidence of CT infarcts was not associated with age or MBP. Diabetics or those with definite CAD had no difference in the incidence of cerebral infarction. Diabetics with definite CAD (51/796) had a greater incidence of CT infarcts (33% vs 21%, p = 0.03) compared with those without evidence of CAD and diabetes together (745/796).

CONCLUSIONS

In ACST, CT infarcts are more prevalent in men compared to women, and in diabetics with CAD. There was no difference in the incidence of CT infarction by age, mean BP, or by the presence of diabetes or CAD alone.

The prevalence of cerebral infarcts in the Asymptomatic Carotid Surgery Trial (ACST) in relation to prior contralateral symptoms

BACKGROUND

The ACST has randomised over 1670 patients to determine if carotid endarterectomy (CEA) prolongs stroke free survival versus best medical treatment alone. Some patients have had contralateral symptoms to the side under investigation, for which CEA may have been performed. This study aims to determine the prevalence of hemispheric cerebral infarcts in relation to prior contralateral symptoms.

METHODS

Patients with preoperative CT or MR scans were divided into those with prior contralateral stroke, cortical TIA, amaurosis fugax or no symptoms.

RESULTS

There were 1144 patients with preoperative CT and 170 patients with MR scans. Incidence of contralateral hemispheric CT and MR infarcts were 19% (222/1144) and 20% (34/170) respectively. Those with prior contralateral stroke (141) had the highest incidence of hemispheric CT infarcts (62%). Those with TIA (129) had a 30% incidence of CT infarct. Incidence of hemispheric CT infarcts were 17% with amaurosis fugax (46) and 10% with no prior symptoms (803). Mantel-Haenszel test for linear association was significant (p < 0.001) for increasing severity of symptoms. Considering MR scans, those with prior contralateral stroke (17) had the highest incidence of hemispheric MR infarcts (53%). Patients with TIA (23) or amaurosis fugax (6) had a 27% incidence of MR infarction. Those with no prior symptoms (121) had a 14% incidence of MR infarcts. Mantel-Haenszel test was significant (p < 0.001).

CONCLUSIONS

In the ACST, currently asymptomatic patients have an incidence of contralateral hemispheric CT and MR infarcts proportional to the severity of prior contralateral symptoms.

Is another clinical trial warranted regarding endarterectomy for asymptomatic carotid stenosis?

BACKGROUND

Several clinical trials regarding carotid endarterectomy for asymptomatic stenosis have been conducted in the past two decades. These research studies have not resolved the controversy regarding the optimal treatment of patients with this condition.

SUMMARY OF REVIEW

We examine some of the reasons why there is persisting uncertainty regarding the value of carotid endarterectomy for asymptomatic stenosis. These include the sample size of earlier studies, the generalizability of these studies, and the clinical importance of the reported surgical benefits in some studies. We then review the rationale for another, larger clinical trial.

CONCLUSIONS

The role of endarterectomy for asymptomatic stenosis remains an unsettled issue. A larger clinical trial may shed light on how to best identify which patients derive clinically significant benefits from prophylactic carotid artery surgery.

Are we detecting and operating on high risk patients in the asymptomatic carotid surgery trial? The Asymptomatic Carotid Surgery Trial Collaborators

OBJECTIVE

This study aims to determine whether asymptomatic carotid surgery trial (ACST) centres have entered and can identify high risk patients using duplex.

DESIGN

Retrospective study.

MATERIALS AND METHODS

Eighty-six vascular laboratories collaborating in ACST were studied, Equipment, operator experience, methodology and interpretation criteria were assessed. The ACST randomisation data were examined to determine whether patients believed to be at higher risk of stroke because of tight stenosis, contralateral occlusion or echolucent plaque were randomised.

RESULTS

Laboratories (92%) had colour duplex and 62% of all operators had > 3 years experience in carotid evaluation. The Doppler angle used to obtain peak velocity was 30-60 degrees in 65%, 60 degrees in 28% and 60-80 degrees in 6% of laboratories. Sixty-two per cent reported diameter reduction, 27% area reduction, and 11% used both methods. One-third of 1657 randomised patients were reported to have ipsilateral echolucent plaque. Median ipsilateral stenosis was 80%, 8% had contralateral occlusion and 8.5% had bilateral > 80% stenosis.

CONCLUSIONS

Centres in ACST use experienced operators, high quality equipment and conscientious data recording. Variations in methods of determining carotid stenosis exist, but can be smoothed by simple data collection. Patients at higher perceived risk of stroke are being entered and with continued recruitment it should be possible to determine whether surgery improves disabling stroke-free survival.

Resuscitation in special circumstances

Basic and Advanced Life Support Guidelines should be followed as normal in cardiorespiratory arrest where there are 'special circumstances' such as near drowning, hypothermia, electrocution, poisoning, anaphylaxis and pregnancy. In order to increase the chances of a successful outcome there are specific considerations and actions that need to be taken. These will be discussed in this paper, the fifth in our resuscitation series.

Nutrition and the healthy adult

Great public concern over the constituents of diets, encouraged by widely publicised and often conflicting advice on what constitutes 'healthy' and 'unhealthy' items, is placing pressures on nurses to understand the nutritional make-up of foods and their uses and abuses. Anne Halliday takes a general look at the requirements of the healthy adult and suggests that there is a need for individuals to review the nature of their whole diet, not merely one or two constituents of it. Nurses will find her article invaluable from a personal as well as professional perspective.

Alcohol abuse in women seeking gynecologic care

In several retrospective studies, alcoholic women have reported menstrual problems significantly more often than nonalcoholic women. There is no information, however, comparing the prevalence of alcohol abuse in women who receive periodic gynecologic care and those who seek care for menstrual disorders such as the premenstrual syndromes. This question was studied in two private practice settings. Women seeking periodic care were obtained from a suburban, general gynecology practice. Women seeking treatment for premenstrual syndrome (PMS) were obtained from a practice that specialized in the care of PMS. Ninety-five patients with PMS and 147 patients seeking periodic care were screened with the CAGE questions--a mnemonic for attempts to Cut back on drinking, being Annoyed at criticism about drinking, feeling Guilty about drinking, and using alcohol as an Eye-opener. Women who gave affirmative responses to one or more of the CAGE questions were evaluated for the presence of alcohol abuse. In the women seeking periodic care, 33% were CAGE positive and 12% were alcohol abusers. In the PMS practice, 51% were CAGE positive and 21% were alcohol abusers. Alcohol abuse is a common problem in gynecologic practice. Women who seek medical care for PMS are at much greater risk to be alcohol abusers.