Author
Thomas E Locker
Other affiliations: Barnsley Hospital NHS Foundation Trust, College of Emergency Medicine, Northern General Hospital
Bio: Thomas E Locker is an academic researcher from University of Sheffield. The author has contributed to research in topics: Emergency department & Public health surveillance. The author has an hindex of 18, co-authored 27 publications receiving 1472 citations. Previous affiliations of Thomas E Locker include Barnsley Hospital NHS Foundation Trust & College of Emergency Medicine.
Papers
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TL;DR: Care in a chest pain observation unit seems to be more effective and more cost effective than routine care for patients with acute, undifferentiated chest pain.
Abstract: Objectives To measure the effectiveness and cost effectiveness of providing care in a chest pain observation unit compared with routine care for patients with acute, undifferentiated chest pain. Design Cluster randomised controlled trial, with 442 days randomised to the chest pain observation unit or routine care, and cost effectiveness analysis from a health service costing
254 citations
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TL;DR: It is identified that there is a group of patients who present repeatedly due to non-random events, confirming the existence of “frequent users” in the ED.
Abstract: Objective: This study aimed to develop a definition of frequent use of an emergency department (ED) by comparing differences in the observed frequency distribution with that of a theoretical frequency distribution. Methods: A retrospective analysis of attendance of ED and minor injury unit attendances in one city over 1 year was conducted. From these data, the expected frequency distribution was determined based upon a Poisson distribution. Results: During the period studied, 75 141 people attended on 98 908 occasions. The theoretical frequency distribution showed that there were 2764 (3.7%) “frequent users” presenting repeatedly due to non-random events. These patients made 12 316 (12.4%) attendances. Frequent users were older than chance users (mean age 49.7 vs 44.5 years). A greater proportion arrived by ambulance (55.3% vs 27.5%), presented with psychiatric problems (5.8% vs 1.1%) or alcohol intoxication (1.3% vs 0.5%), and were admitted to hospital (37.4% vs 19.6%). Conclusion: We have identified that there is a group of patients who present repeatedly due to non-random events, confirming the existence of “frequent users”. Their characteristics are clearly different to other patients in the ED. We propose that “frequent users” be defined as any patient who makes more than four attendances per year.
187 citations
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TL;DR: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance.
Abstract: Objectives:
To estimate the diagnostic accuracy of
non-invasive tests for proximal deep vein thrombosis
(DVT) and isolated calf DVT, in patients with clinically
suspected DVT or high-risk asymptomatic patients, and
identify factors associated with variation in diagnostic
performance. Also to identify practical diagnostic
algorithms for DVT, and estimate the diagnostic
accuracy, clinical effectiveness and cost-effectiveness
of each.
Data sources:
Electronic databases (to April 2004).
A postal survey of hospitals in the UK.
Review methods:
Selected studies were assessed
against validated criteria. A postal survey of hospitals in
the UK was undertaken to describe current practice
and availability of tests, and identify additional
diagnostic algorithms. Pooled estimates of sensitivity,
specificity and likelihood ratios were obtained for each
test using random effects meta-analysis. The effect of
study-level covariates was explored using random
effects metaregression. A decision-analytic model was
used to combine estimates from the meta-analysis and
estimate the diagnostic performance of each algorithm
in a theoretical population of outpatients with
suspected DVT. The net benefit of using each algorithm
was estimated from a health service perspective, using
cost–utility analysis, assuming thresholds of willingness
to pay of £20,000 and £30,000 per quality-adjusted lifeyear
(QALY). The model was analysed probabilistically
and cost-effectiveness acceptability curves were
generated to reflect uncertainty in estimated costeffectiveness.
Results:
Individual clinical features are of limited
diagnostic value, with most likelihood ratios being close
to 1. Wells clinical probability score stratifies proximal,
but not distal, DVT into high-, intermediate- and
low-risk categories. Unstructured clinical assessment by
experienced clinicians may have similar performance to
Wells score. In patients with clinically suspected DVT,
D-dimer has 91% sensitivity and 55% specificity for
DVT, although performance varies substantially
between assays and populations. D-dimer specificity is
dependent on pretest clinical probability, being higher
in patients with a low clinical probability of DVT.
Plethysmography and rheography techniques have
modest sensitivity for proximal DVT, poor sensitivity
for distal DVT, and modest specificity. Ultrasound has
94% sensitivity for proximal DVT, 64% sensitivity for
distal DVT and 94% specificity. Computed tomography
scanning has 95% sensitivity for all DVT (proximal and
distal combined) and 97% specificity. Magnetic
resonance imaging has 92% sensitivity for all DVT and
95% specificity. The diagnostic performance of all tests
is worse in asymptomatic patients. The most costeffective
algorithm discharged patients with a low Wells
score and negative D-dimer without further testing,
and then used plethysmography alongside ultrasound,
with venography in selected cases, to diagnose the
remaining patients. However, the cost-effectiveness of
this algorithm was dependent on assumptions of test
independence being met and the ability to provide
plethysmography at relatively low cost. Availability of
plethysmography and venography is currently limited at
most UK hospitals, so implementation would involve
considerable reorganisation of services. Two algorithms
were identified that offered high net benefit and would
be feasible in most hospitals without substantial
reorganisation of services. Both involved using a
combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of
£10,000 or £20,000 per QALY the optimal strategy
involved discharging patients with a low or
intermediate Wells score and negative D-dimer,
ultrasound for those with a high score or positive
D-dimer, and repeat scanning for those with positive
D-dimer and a high Wells score, but negative initial
scan. For thresholds of £30,000 or more a similar
strategy, but involving repeat ultrasound for all those
with a negative initial scan, was optimal.
Conclusions:
Diagnostic algorithms based on a
combination of Wells score, D-dimer and ultrasound
(with repeat if negative) are feasible at most UK
hospitals and are among the most cost-effective. Use of
repeat scanning depends on the threshold for
willingness to pay for health gain. Further diagnostic
testing for patients with a low Wells score and negative
D-dimer is unlikely to represent a cost-effective use of
resources. Recommendations for research include the
evaluation of the costs and outcomes of using the
optimal diagnostic algorithms in routine practice, the
development and evaluation of algorithms appropriate
for specific groups of patients with suspected DVT,
such as intravenous drug abusers, pregnant patients and
those with previous DVT, the evaluation of the role of
plethysmography: interaction with other diagnostic
tests, outcome of low-risk patients with negative
plethysmography and measurement of the costs of
providing plethysmography, and methodological
research into the incorporation of meta-analytic data
into decision-analytic modelling.
183 citations
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TL;DR: Important differences exist when clinical features are specifically investigated in patients with acute chest pain and a nondiagnostic electrocardiogram.
Abstract: Objectives: To measure the predictive value and diagnostic performance of clinical features used to diagnose coronary syndromes in patients presenting with acute, undifferentiated chest pain. Methods: The clinical features of patients presenting to the authors' chest pain unit with acute, undifferentiated chest pain were prospectively recorded on a standard form. Admitted patients were followed up by case note review. Discharged patients were followed up as outpatients three days later. Six months after the emergency department visit, evidence of adverse events was searched for from the hospital computer database, case notes, and the patient's primary care physician. The authors tested the power of each feature to predict: 1) acute myocardial infarction (AMI) by World Health Organization criteria, and 2) any acute coronary syndrome (ACS), evidenced by cardiac testing, AMI, arrhythmia, death, or revacsularization procedure within six months. Results: Eight hundred ninety-three patients were assessed, 34 (3.8%) with AMI and 81 (9.1%) with ACS. Features useful in the diagnosis of AMI were exertional pain [likelihood ratio (LR) = 2.35], pain radiating to the shoulder or both arms (LR = 4.07), and chest wall tenderness (LR = 0.3). Features useful in the diagnosis of ACS were exertional pain (LR = 2.06) and pain radiating to the shoulder, the left arm, or both arms (LR = 1.62). The site or nature of pain and the presence of nausea, vomiting, or diaphoresis were not predictive of AMI or ACS. Conclusions: Important differences exist when clinical features are specifically investigated in patients with acute chest pain and a nondiagnostic electrocardiogram. Clinical features have a limited role to play in triage decision making.
143 citations
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TL;DR: The introduction of a time target reduced the proportion of patients staying greater than 4 hours and more patients departed within 20 minutes of the target 4-hour interval after the mandate, notably, the elderly.
133 citations
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01 Jan 2009
TL;DR: Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients and Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients.
Abstract: OBJECTIVE — To systematically review the incidence of posttransplantation diabetes (PTD), risk factors for its development, prognostic implications, and optimal management. RESEARCH DESIGN AND METHODS — We searched databases (MEDLINE, EMBASE, the Cochrane Library, and others) from inception to September 2000, reviewed bibliographies in reports retrieved, contacted transplantation experts, and reviewed specialty journals. Two reviewers independently determined report inclusion (original studies, in all languages, of PTD in adults with no history of diabetes before transplantation), assessed study methods, and extracted data using a standardized form. Meta-regression was used to explain between-study differences in incidence. RESULTS — Nineteen studies with 3,611 patients were included. The 12-month cumulative incidence of PTD is lower (10% in most studies) than it was 3 decades ago. The type of immunosuppression explained 74% of the variability in incidence (P 0.0004). Risk factors were patient age, nonwhite ethnicity, glucocorticoid treatment for rejection, and immunosuppression with high-dose cyclosporine and tacrolimus. PTD was associated with decreased graft and patient survival in earlier studies; later studies showed improved outcomes. Randomized trials of treatment regimens have not been conducted. CONCLUSIONS — Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients. Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients, paying particular attention to interactions with immunosuppressive drugs. Diabetes Care 25:583–592, 2002
3,716 citations
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TL;DR: In contrast to adults, cardiac arrest in infants and children does not usually result from a primary cardiac cause, more often it is the terminal result of progressive respiratory failure or shock, also called an asphyxial arrest.
Abstract: In contrast to adults, cardiac arrest in infants and children does not usually result from a primary cardiac cause. More often it is the terminal result of progressive respiratory failure or shock, also called an asphyxial arrest. Asphyxia begins with a variable period of systemic hypoxemia, hypercapnea, and acidosis, progresses to bradycardia and hypotension, and culminates with cardiac arrest.1
Another mechanism of cardiac arrest, ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), is the initial cardiac rhythm in approximately 5% to 15% of pediatric in-hospital and out-of-hospital cardiac arrests;2,–,9 it is reported in up to 27% of pediatric in-hospital arrests at some point during the resuscitation.6 The incidence of VF/pulseless VT cardiac arrest rises with age.2,4 Increasing evidence suggests that sudden unexpected death in young people can be associated with genetic abnormalities in myocyte ion channels resulting in abnormalities in ion flow (see “Sudden Unexplained Deaths,” below).
Since 2010 marks the 50th anniversary of the introduction of cardiopulmonary resuscitation (CPR),10 it seems appropriate to review the progressive improvement in outcome of pediatric resuscitation from cardiac arrest. Survival from in-hospital cardiac arrest in infants and children in the 1980s was around 9%.11,12 Approximately 20 years later, that figure had increased to 17%,13,14 and by 2006, to 27%.15,–,17 In contrast to those favorable results from in-hospital cardiac arrest, overall survival to discharge from out-of-hospital cardiac arrest in infants and children has not changed substantially in 20 years and remains at about 6% (3% for infants and 9% for children and adolescents).7,9
It is unclear why the improvement in outcome from in-hospital cardiac arrest has occurred, although earlier recognition and management of at-risk patients on general inpatient units …
1,846 citations
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TL;DR: In this article, the authors proposed a two-dimensional magnetic resonance imaging (2D) and three-dimensional (3D) image of the human femoral artery for the diagnosis of acute coronary syndrome.
Abstract: 2D
: two-dimensional
3D
: three-dimensional
ABI
: ankle–brachial index
ACAS
: Asymptomatic Carotid Atherosclerosis Study
ACCF
: American College of Cardiology Foundation
ACE
: angiotensin-converting enzyme
ACS
: acute coronary syndrome
ACST
: Asymptomatic Carotid Surgery Trial
ALI
: acute limb ischaemia
ASTRAL
: Angioplasty and Stenting for Renal Artery Lesions trial
BASIL
: Bypass versus Angioplasty in Severe Ischaemia of the Leg
BOA
: Dutch Bypass Oral Anticoagulants or Aspirin
CABG
: coronary artery bypass grafting
CAD
: coronary artery disease
CAPRIE
: Clopidogrel versus Aspirin in Patients at Risk for Ischaemic Events
CAPTURE
: Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events
CARP
: Coronary Artery Revascularization Prophylaxis
CAS
: carotid artery stenting
CASPAR
: Clopidogrel and Acetylsalicylic Acid in Bypass Surgery for Peripheral Arterial Disease
CASS
: Coronary Artery Surgery Study
CAVATAS
: CArotid and Vertebral Artery Transluminal Angioplasty Study
CEA
: carotid endarterectomy
CHARISMA
: Clopidogrel for High Atherothrombotic Risk and Ischaemic Stabilization, Management and Avoidance
CI
: confidence interval
CLEVER
: Claudication: Exercise Versus Endoluminal Revascularization
CLI
: critical limb ischaemia
CORAL
: Cardiovascular Outcomes in Renal Atherosclerotic Lesions
COURAGE
: Clinical Outcomes Utilization Revascularization and Aggressive Drug Evaluation
CPG
: Committee for Practice Guidelines
CREST
: Carotid Revascularization Endarterectomy vs. Stenting Trial
CT
: computed tomography
CTA
: computed tomography angiography
CVD
: cardiovascular disease
DECREASE-V
: Dutch Echocardiographic Cardiac Risk Evaluation
DRASTIC
: Dutch Renal Artery Stenosis Intervention Cooperative Study
DSA
: digital subtraction angiography
DUS
: duplex ultrasound/duplex ultrasonography
EACTS
: European Association for Cardio-Thoracic Surgery
EAS
: European Atherosclerosis Society
ECST
: European Carotid Surgery Trial
EPD
: embolic protection device
ESC
: European Society of Cardiology
ESH
: European Society of Hypertension
ESRD
: end-stage renal disease
EUROSCORE
: European System for Cardiac Operative Risk Evaluation
EVA-3S
: Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis
EXACT
: Emboshield and Xact Post Approval Carotid Stent Trial
GALA
: General Anaesthesia versus Local Anaesthesia for Carotid Surgery
GFR
: glomerular filtration rate
GRACE
: Global Registry of Acute Coronary Events
HbA1c
: glycated haemoglobin
HDL
: high-density lipoprotein
HOPE
: Heart Outcomes Prevention Evaluation
HR
: hazard ratio
IC
: intermittent claudication
ICSS
: International Carotid Stenting Study
IMT
: intima–media thickness
ITT
: intention to treat
LDL
: low-density lipoprotein
LEAD
: lower extremity artery disease
MACCEs
: major adverse cardiac and cerebrovascular events
MDCT
: multidetector computed tomography
MONICA
: Monitoring of Trends and Determinants in Cardiovascular Disease
MRA
: magnetic resonance angiography
MRI
: magnetic resonance imaging
NASCET
: North American Symptomatic Carotid Endarterectomy Trial
ONTARGET
: Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial
OR
: odds ratio
PAD
: peripheral artery diseases
PARTNERS
: Peripheral Arterial Disease Awareness, Risk, and Treatment: New Resources for Survival
PCI
: percutaneous coronary intervention
PET
: positron emission tomography
PRO-CAS
: Predictors of Death and Stroke in CAS
PTA
: percutaneous transluminal angioplasty
RAAS
: renin–angiotensin–aldosterone system
RADAR
: Randomized, Multicentre, Prospective Study Comparing Best Medical Treatment Versus Best Medical Treatment Plus Renal Artery Stenting in Patients With Haemodynamically Relevant Atherosclerotic Renal Artery Stenosis
RAS
: renal artery stenosis
RCT
: randomized controlled trial
REACH
: Reduction of Atherothrombosis for Continued Health
RR
: risk ratio
SAPPHIRE
: Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy
SCAI
: Society for Cardiovascular Angiography and Interventions
SIR
: Society of Interventional Radiology
SPACE
: Stent-Protected Angioplasty versus Carotid Endarterectomy
SPARCL
: Stroke Prevention by Aggressive Reduction in Cholesterol Levels Study
STAR
: Stent Placement in Patients With Atherosclerotic Renal Artery Stenosis and Impaired Renal Function
SSYLVIA
: Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries
SVMB
: Society for Vascular Medicine and Biology
TASC
: TransAtlantic Inter-Society Consensus
TIA
: transient ischaemic attack
UEAD
: upper extremity artery disease
VA
: vertebral artery
Guidelines summarize and evaluate all available evidence, at the time of the writing process, on a particular issue with the aim of assisting physicians in selecting the best management strategies for an individual patient, with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are no substitutes but are complements for textbooks and cover the ESC Core Curriculum topics. Guidelines and recommendations should help the physicians to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible physician(s).
A large number of Guidelines have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organizations. Because of the impact on clinical practice, quality criteria for the development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines can be found on the ESC website (http://www.escardio.org/guidelines-surveys/esc-guidelines/about/Pages/rules-writing.aspx). ESC Guidelines represent the official position of the ESC on a given topic and are regularly updated.
Members of this Task Force were selected by the ESC to represent professionals involved with the medical care of patients with this pathology. Selected experts in the field undertook a comprehensive review of the published evidence for diagnosis, management, and/or prevention of a given condition according to ESC Committee for Practice Guidelines (CPG) policy. A critical evaluation of diagnostic and therapeutic procedures was performed including assessment of the risk–benefit ratio. Estimates of expected health outcomes for larger populations were included, where data exist. The level of evidence and the strength of recommendation of particular treatment options were weighed and graded according to pre-defined scales, as outlined in Tables 1 and 2 . …
1,266 citations
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TL;DR: In this article, the authors examine the robustness of the regime of targets and terror to these assumptions using evidence from the English public health service on reported successes, problems of measurement, and gaming.
Abstract: In the 2000s, governments in the UK, particularly in England, developed a system of governance of public services that combined targets with an element of terror This has obvious parallels with the Soviet regime, which was initially successful but then collapsed Assumptions underlying governance by targets represent synecdoche (taking a part to stand for a whole); and that problems of measurement and gaming do not matter We examine the robustness of the regime of targets and terror to these assumptions using evidence from the English public health service on reported successes, problems of measurement, and gaming Given this account, we consider the adequacy of current audit arrangements and ways of developing governance by targets in order to counter the problems we have identified
1,210 citations
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TL;DR: There was convincing evidence that outcome reporting bias exists and has an impact on the pooled summary in systematic reviews, and empirical evidence suggests that published studies tended to report a greater treatment effect than those from the grey literature.
Abstract: Objectives To identify and appraise empirical studies on publication and related biases published since 1998; to assess methods to deal with publication and related biases; and to examine, in a random sample of published systematic reviews, measures taken to prevent, reduce and detect dissemination bias. Data sources The main literature search, in August 2008, covered the Cochrane Methodology Register Database, MEDLINE, EMBASE, AMED and CINAHL. In May 2009, PubMed, PsycINFO and OpenSIGLE were also searched. Reference lists of retrieved studies were also examined. Review methods In Part I, studies were classified as evidence or method studies and data were extracted according to types of dissemination bias or methods for dealing with it. Evidence from empirical studies was summarised narratively. In Part II, 300 systematic reviews were randomly selected from MEDLINE and the methods used to deal with publication and related biases were assessed. Results Studies with significant or positive results were more likely to be published than those with non-significant or negative results, thereby confirming findings from a previous HTA report. There was convincing evidence that outcome reporting bias exists and has an impact on the pooled summary in systematic reviews. Studies with significant results tended to be published earlier than studies with non-significant results, and empirical evidence suggests that published studies tended to report a greater treatment effect than those from the grey literature. Exclusion of non-English-language studies appeared to result in a high risk of bias in some areas of research such as complementary and alternative medicine. In a few cases, publication and related biases had a potentially detrimental impact on patients or resource use. Publication bias can be prevented before a literature review (e.g. by prospective registration of trials), or detected during a literature review (e.g. by locating unpublished studies, funnel plot and related tests, sensitivity analysis modelling), or its impact can be minimised after a literature review (e.g. by confirmatory large-scale trials, updating the systematic review). The interpretation of funnel plot and related statistical tests, often used to assess publication bias, was often too simplistic and likely misleading. More sophisticated modelling methods have not been widely used. Compared with systematic reviews published in 1996, recent reviews of health-care interventions were more likely to locate and include non-English-language studies and grey literature or unpublished studies, and to test for publication bias. Conclusions Dissemination of research findings is likely to be a biased process, although the actual impact of such bias depends on specific circumstances. The prospective registration of clinical trials and the endorsement of reporting guidelines may reduce research dissemination bias in clinical research. In systematic reviews, measures can be taken to minimise the impact of dissemination bias by systematically searching for and including relevant studies that are difficult to access. Statistical methods can be useful for sensitivity analyses. Further research is needed to develop methods for qualitatively assessing the risk of publication bias in systematic reviews, and to evaluate the effect of prospective registration of studies, open access policy and improved publication guidelines.
844 citations