Accurate, practical and cost-effective assessment of carotid stenosis in the UK

OBJECTIVES

To determine whether less invasive imaging tests [ultrasound (US), magnetic resonance angiography (MRA), computed tomographic angiography (CTA) and contrast-enhanced MRA (CEMRA)], alone or combined, could replace intra-arterial angiography (IAA), what effect this would have on strokes and deaths, endarterectomies performed and costs, and whether less invasive tests were cost-effective.

DATA SOURCES

Electronic databases covering the years 1980-2003 inclusive, updated to April 2004. Key journals from 1990 to the end of 2002.

REVIEW METHODS

The authors constituted a panel of experts in stroke, imaging, vascular surgery, statistics and health economic modelling. The accuracy of less invasive carotid imaging was systematically reviewed using Standards for Reporting of Diagnostic Accuracy (STARD) methodology, supplemented by individual patient data from UK primary research and audit studies. A systematic review of the costs of less invasive tests, outpatient clinics, endarterectomy and stroke was performed, along with a microcosting exercise. A model of the process of care following a transient ischaemic attack (TIA)/minor stroke was developed, populated with data from stroke epidemiology studies in the UK, effects of medical and surgical interventions, outcomes, quality of life and costs. A survey of UK stroke prevention clinics provided typical timings. Twenty-two different carotid imaging strategies were evaluated for short- and long-term outcomes, quality-adjusted life-years (QALYs) and net benefit.

RESULTS

In 41 included studies (2404 patients, median age 60-65 years), most data were available on 70-99% stenosis. CEMRA was the most accurate [sensitivity 0.94, 95% confidence interval (CI) 0.88 to 0.97; specificity 0.93, 95% CI 0.89 to 0.96], compared with US, MRA and CTA, which were all similar (e.g. for US: sensitivity 0.89, 95% CI 0.85 to 0.92; specificity 0.84, 95% CI 0.77 to 0.89). Data for 50-69% stenoses and on combinations of tests were too sparse to be reliable. There was heterogeneity between studies for all imaging modalities except for CTA. The individual patient data (2416 patients) showed that the literature overestimated test accuracy in routine practice and that, in general, tests perform with higher sensitivity and specificity in asymptomatic than in symptomatic arteries. In the cost-effectiveness model, on current UK timings, strategies allowed more patients to reach endarterectomy very quickly, and where those with 50-69% stenosis would be offered surgery in addition to those with 70-99%, prevented most strokes and produced greatest net benefit. This included most strategies with US as first or repeat test, and not those with IAA. However, the model was sensitive to less invasive test accuracy, cost and timing of endarterectomy. In patients investigated late after TIA, test accuracy is crucial and CEMRA should be used before surgery.

CONCLUSIONS

In the UK, less invasive tests can be used in place of IAA if radiologists trained in carotid imaging are available. Imaging should be carefully audited. Stroke prevention clinics should reduce waiting times at all stages to improve speed of access to endarterectomy. In patients presenting late after TIA, test accuracy is very important and US results should be confirmed by CEMRA, as patients with 50-69% stenosis are less likely to benefit. More data are required to define the accuracy of the less invasive tests, with improvements made in the data collection methods used and how data are presented. Consideration should also be given to the use of new technologies and randomised trials.

How should we diagnose suspected deep-vein thrombosis?

BACKGROUND

Many different approaches are used to diagnose suspected deep-vein thrombosis (DVT), but there has been little formal comparison of strategies.

AIM

To identify the most cost-effective strategy for the UK National Health Service (NHS).

DESIGN

Systematic review, meta-analysis and cost-effectiveness analysis.

METHODS

We identified 18 strategies and estimated the diagnostic performance of constituent tests by systematic review and meta-analysis. Outcomes of testing and treatment were estimated from published data or by an expert panel. Costs were estimated from NHS reference costs and published data. We built a decision-analysis model to estimate, for each strategy, the overall accuracy, costs, and outcomes (valued as quality-adjusted life-years, QALYs), compared to a 'no testing, no treatment' alternative. Probabilistic analysis estimated the net benefit of each strategy at varying thresholds for willingness to pay for health gain.

RESULTS

At the thresholds for willingness to pay recommended by the National Institute for Clinical Excellence (20,000 pounds sterling-30,000 pounds sterling per QALY), the optimal strategy was to discharge patients with a low or intermediate Wells score and negative D-dimer, limiting ultrasound to those with a high score or positive D-dimer. Strategies using radiological testing for all patients were only cost-effective at 40,000 pound sterling per QALY or more.

DISCUSSION

The optimal strategy for DVT diagnosis is to use ultrasound selectively in patients with a high clinical risk or positive D-dimer. Radiological testing for all patients does not appear to be a cost-effective use of health service resources.

Chick embryo lethal orphan virus can be polymer-coated and retargeted to infect mammalian cells

Non-human adenovirus vectors have attractive immunological properties for gene therapy but are frequently restricted by inefficient transduction of human target cells. Using chicken embryo lethal orphan (CELO) virus, we employed a nongenetic mechanism of polymer coating and retargeting with basic fibroblast growth factor (bFGF-pc-CELOluc), a strategy that permits efficient tropism modification of human adenovirus. bFGF-pc-CELOluc showed efficient uptake and transgene expression in chick embryo fibroblasts (CEF), and increased levels of binding and internalization in a variety of human cell lines. Transgene expression was also greater than unmodified CELOluc in PC-3 human prostate cells, although the specific activity (RLU per internalized viral genome) was decreased. In CEF, the specific activity of bFGF-pc-CELOluc was considerably higher than in the human prostate cell line PC-3. Retargeted virus was fully resistant to inhibition by human serum with known adenovirus-neutralizing activity in vitro, while in mice CELOluc was cleared less rapidly from the blood than Adluc following i.v. administration in the presence of adenovirus neutralizing serum. Polymer coating and retargeting with bFGF further reduced rates of clearance for both viruses, suggesting protection against both neutralizing and opsonizing factors. The data indicate that CELO virus may be retargeted to infect human cells via alternative, potentially disease-specific, receptors and resist the effects of pre-existing humoral immunity.

Effect of Ruminally Protected Methionine on Splanchnic Metabolism of Amino Acids in Lactating Dairy Cows

The effect of ruminally protected Met (RPM) on splanchnic metabolism was measured in 3 primiparous and 3 multiparous Holstein cows. Doses of RPM (0, 36, and 72 g/d) were tested in a replicated 3 x 3 Latin square design, over 3 consecutive 14-d experimental periods. A mixed ration was fed in 12 equal meals per d (average dry matter intake: 17.5 +/- 0.08 kg/d). Indwelling catheters were surgically implanted in the mesenteric artery and the portal and hepatic veins for blood collection, as well as in 2 distal branches of the mesenteric vein for infusion of p-aminohippurate to determine blood flow. On d 14 of each period, a temporary catheter was inserted into a mammary vein and 6 hourly blood samples were collected to determine plasma concentrations of metabolites, hormones, and their respective fluxes across the splanchnic bed and mammary glands. Yields of milk (32.8, 32.0, and 32.9 +/- 0.92 kg/d) and protein (1,028, 1,053, and 1,075 +/- 28.7 g/d) were unaffected by level of RPM. However, the true protein content in milk from primiparous cows increased linearly (2.92, 3.09, and 3.34 +/- 0.077%). The addition of RPM linearly increased the net flux of Met across the portal-drained viscera, which resulted in increased arterial Met concentrations (25, 29, and 40 +/- 1.1 microM). Although it had no significant effect on net portal and hepatic fluxes of other essential amino acids, RPM resulted in a linear increase in the total splanchnic output of Ile, Leu, Phe, and Thr. These results suggest that feeding RPM triggered a homeostatic response resulting in less utilization of certain essential amino acids through the gastrointestinal tract and liver. Net mammary uptake of Met did not change with the addition of RPM. However, mammary extraction of Met decreased in a linear fashion in response to increased arterial inflow.

Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon

Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (lambdaCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded lambdaCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by lambdaCgN alone. Combined lambdaCgN/MNU treatments induced greater MTCRII (P < 0.01) as well as greater number (P < 0.001) and crypt multiplicity (P < 0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r = 0.732; P < 0.01). MTCRII are induced by lambdaCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.

A prospective cohort study comparing hospital admission for gastro-enteritis with home management

OBJECTIVES

To compare physical and psychological outcomes in children presenting at Accident and Emergency Departments (A&E), diagnosed with gastro-enteritis and admitted to hospital with those of a similar age, sex and severity of illness discharged home. The physical and psychological well-being of children in these two groups, in the month after the episode, were compared as was further use of health care services.

DESIGN

A prospective cohort study.

METHODS

A comparison of 116 children aged 1-6 years with gastro-enteritis, presenting at A&E over a 6 months period. Admitted children were compared with children discharged, of a similar age, sex and illness severity (triage score) with follow-up at 1 week and 1 month. Clinical history, psychosocial factors, investigations and outcomes were recorded at presentation and physical, psychological and family outcomes at 1 week and 1 month.

RESULTS

Of 116 children, 112 (97%) completed the study (56 in each group). No differences were detected in psychosocial factors, socio-economic status, family factors, time of arrival at A&E or waiting times. Parental perception of illness was greater in the admitted group (P < 0.005), but was recorded after the decision on admission was made. At 1 week follow-up admitted children had increased separation anxiety compared with children who were discharged (P < 0.05), but this difference disappeared at 1 month. Clinical outcomes were the same for both groups, although admitted children had more investigations (91% vs. 39%). Parents were equally satisfied with their child's treatment, but one-third of children in both groups sought further consultation with a health professional in the following week.

CONCLUSIONS

There is no statistically significant difference in socio-demographic data, time of arrival at A&E, waiting times, clinical and psychosocial outcomes in children with acute gastro-enteritis admitted to hospital compared with a group of children of similar age, gender and severity of illness managed at home. However, parents seek reassurance and follow-up of acutely ill children, even if the child is admitted to hospital, which has service and resource implications.

The validity of a four week self-recall of sports injuries

The ability of sports injury studies to provide reliable incidence estimates depends on accurate injury data. One of the most commonly used methods of collecting injury data is through self-report, but the validity of such information is largely unknown. This study validated a four week self-report sports injury recall against a range of external sources including hospital records, health practitioner records, and third parties. Cases were drawn from the larger, Western Australian Sports Injury Study (WASIS). This study demonstrates acceptable to good levels of agreement between self-report and more objective data in relation to details such as the nature and body part injured, and the level of injury treatment sought (kappa = 0.48 to 0.78). However, self-reported injury severity did not agree with the Injury Severity Score classification of severity.

The influence of lower face vertical proportion on facial attractiveness

This study investigated the influence of changing lower face vertical proportion on the attractiveness ratings scored by lay people.Ninety-two social science students rated the attractiveness of a series of silhouettes with normal, reduced or increased lower face proportions. The random sequences of 10 images included an image with the Eastman normal lower face height relative to total face height [lower anterior face height/total anterior face height (LAFH/TAFH) of 55 per cent], and images with LAFH/TAFH increased or decreased by up to four standard deviations (SD) from the Eastman norm. All the images had a skeletal Class I antero-posterior (AP) relationship. A duplicate image in each sequence assessed repeatability. The participants scored each image using a 10 point numerical scale and also indicated whether they would seek treatment if the image was their own profile. The profile image with normal vertical facial proportions was rated by the lay people as the most attractive. Attractiveness scores reduced as the vertical facial proportions diverged from the normal value. Images with a reduced lower face proportion were rated as significantly more attractive than the corresponding images with an increased lower face proportion. Images with a reduced lower face proportion were also significantly less likely to be judged as needing treatment than the corresponding images with an increased lower face proportion.

Use of ecological study designs for injury prevention

This paper provides an overview of the ecological study design and its application to injury prevention. The advantages and disadvantages of ecological designs are described and the principle characteristics of the ecological design are highlighted. The paper concludes by highlighting the pivotal role that ecological studies can have in our understanding of the complex interaction between the environment and injury, and the application of this design in elucidating key population based strategies for injury prevention.

Incidence and risk factors for injury in non-elite Australian Football

This paper identifies the risk and protective factors for injury in non-elite Australian Football. Five hundred and thirty five non-elite Australian footballers completed a baseline questionnaire at the commencement of the 1997 preseason. Participants were telephoned each month during the 1997 and 1998 playing seasons to provide details of their exposure at training and games and any injury experiences in the previous four weeks. The incidence of injury in this study was 24 injuries per 1000 player hours. The risk factors for injury were identified as: not wearing sports-specific football boots (IRR 1.40, 95% CI 1.03-1.90); an existing back pathology (IRR 1.29, 95% CI 1.10-1.51); excessive foot pronation (IRR 1.29, 95% CI 1.07-1.56); and extroverted behaviour (IRR 1.01, 95% CI 1.00-1.03). Cooling down after training (IRR 0.95, 95% CI 0.90-0.99) and not being injured in the previous 12 months (IRR 0.73, 95% CI 0.61-0.88) were found to be protective against injury. This study found that there was a high risk of injury associated with playing Australian Football at a community level. Further research is required to gain an understanding of the mechanisms by which the identified risk factors influence injury risk in community level Australian Football.

Autoclave use in dental practice in the Republic of Ireland

AIMS

To assess by postal questionnaire, cross-infection control methods, especially sterilisation procedures, of 700 general dental practitioners in the Republic of Ireland, and to biologically monitor steam pressure sterilisers or autoclaves in their practices.

MAIN OUTCOME MEASURES

Methods of instrument cleaning and sterilisation, autoclave efficacy.

RESULTS

A response rate of 40% with all, except one practitioner, using steam sterilisation. 49% also reported the use of chemical sterilisation with a quarter of these using glutaraldehyde. However, instrument soaking time varied greatly from 2.5 minutes to 74 hours. Methods of instrument cleaning prior to autoclaving were as follows: scrubbing by hand 41.5%, ultrasonic cleaning 7.0%, combination of both 50%. 52.9% of the respondents did not autoclave their dental handpieces and only 44.7% disinfected impressions before sending them to the laboratory. The autoclaves of thirty practitioners (11.3%) did not pass the initial biological test. Following counselling about possible causes of failure, four autoclaves (1.5%) failed a repeat biological test. However, seven practitioners did not return the repeat biological test.

CONCLUSIONS

Some aspects of recommended cross-infection control procedures are well adhered to, e.g. instrument cleaning, but further education is required in certain key areas, in particular the use of chemical sterilisation, dental handpiece autoclaving and impression disinfection. There is also a need to increase awareness of the importance of routine autoclave servicing and calibration, along with validation and monitoring.

An algorithm to predict pregnancy in assisted reproduction

BACKGROUND

Male fertility potential cannot be measured by conventional parameters for the assisted reproduction technique; ICSI. This study determines the relationship between testicular and ejaculated sperm mitochondrial (mt) DNA deletions, nuclear (n) DNA fragmentation, and fertilization and pregnancy rates in ICSI.

METHODS

Ejaculated sperm were obtained from 77 men and testicular sperm from 28 men with obstructive azoospermia undergoing ICSI. Testicular sperm were retrieved using a Trucut needle. mtDNA was analysed using a long PCR. The alkaline Comet assay determined nDNA fragmentation.

RESULTS

Of subjects who achieved a pregnancy (50%) using testicular sperm, only 26% had partners' sperm with wild-type (WT) mtDNA. Of pregnant subjects (38%) using ejaculated sperm, only 8% had partner sperm with WT mtDNA. In each, the successful group had less mtDNA deletions and less nDNA fragmentation. There were inverse relationships between pregnancy and mtDNA deletion numbers, size and nDNA fragmentation for both testicular and ejaculated sperm. No relationships were observed with fertilization rates. An algorithm for the prediction of pregnancy is presented based on the quality of sperm nDNA and mtDNA.

CONCLUSION

In both testicular and ejaculated sperm, mtDNA deletions and nDNA fragmentation are closely associated with pregnancy in ICSI.

Clinical outcome of Burkholderia cepacia complex infection in cystic fibrosis adults

BACKGROUND

The Burkholderia cepacia complex (BCC) is one of the most important groups of organisms infecting cystic fibrosis (CF) patients. The aim of the study was to examine how infection with BCC affects clinical outcome.

METHODS

Nineteen CF adults infected with BCC and 19 controls infected with Pseudomonas aeruginosa were studied over a 4-year period. The best forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) for each year were recorded and annual rate of decline calculated.

RESULTS

The BCC infected group displayed a significantly greater reduction of FEV(1) and BMI compared to the P. aeruginosa infected group (p=0.001 and p=0.009, respectively). Sixteen patients infected with a single Burkholderia cenocepacia strain had a significantly greater rate of FEV(1) decline compared to those infected with Burkholderia multivorans (n=3) or P. aeruginosa (p=0.01 and p<0.0001, respectively). The rate of BMI decline was significantly greater in patients infected with B. cenocepacia compared to those with P. aeruginosa (p=0.007), but not significantly different in those with B. multivorans (p=0.29).

CONCLUSION

BCC infection is associated with an accelerated decline in pulmonary function and BMI. Infection with a single B. cenocepacia strain was associated with a more rapid decline in lung function than those infected with either B. multivorans or P. aeruginosa.