Small abdominal aortic aneurysms (AAAs; 3.0-5.4 cm in diameter) are usually asymptomatic and managed by regular ultrasound surveillance until they grow to a diameter threshold (commonly 5.5 cm) at ...which surgical intervention is considered. The choice of appropriate surveillance intervals is governed by the growth and rupture rates of small AAAs, as well as their relative cost-effectiveness.
The aim of this series of studies was to inform the evidence base for small AAA surveillance strategies. This was achieved by literature review, collation and analysis of individual patient data, a focus group and health economic modelling.
We undertook systematic literature reviews of growth rates and rupture rates of small AAAs. The databases MEDLINE, EMBASE on OvidSP, Cochrane Central Register of Controlled Trials 2009 Issue 4, ClinicalTrials.gov, and controlled-trials.com were searched from inception up until the end of 2009. We also obtained individual data on 15,475 patients from 18 surveillance studies.
Systematic reviews of publications identified 15 studies providing small AAA growth rates, and 14 studies with small AAA rupture rates, up to December 2009 (later updated to September 2012). We developed statistical methods to analyse individual surveillance data, including the effects of patient characteristics, to inform the choice of surveillance intervals and provide inputs for health economic modelling. We updated an existing health economic model of AAA screening to address the cost-effectiveness of different surveillance intervals.
In the literature reviews, the mean growth rate was 2.3 mm/year and the reported rupture rates varied between 0 and 1.6 ruptures per 100 person-years. Growth rates increased markedly with aneurysm diameter, but insufficient detail was available to guide surveillance intervals. Based on individual surveillance data, for each 0.5-cm increase in AAA diameter, growth rates increased by about 0.5 mm/year and rupture rates doubled. To control the risk of exceeding 5.5 cm to below 10% in men, on average a 7-year surveillance interval is sufficient for a 3.0-cm aneurysm, whereas an 8-month interval is necessary for a 5.0-cm aneurysm. To control the risk of rupture to below 1%, the corresponding estimated surveillance intervals are 9 years and 17 months. Average growth rates were higher in smokers (by 0.35 mm/year) and lower in patients with diabetes (by 0.51 mm/year). Rupture rates were almost fourfold higher in women than men, doubled in current smokers and increased with higher blood pressure. Increasing the surveillance interval from 1 to 2 years for the smallest aneurysms (3.0-4.4 cm) decreased costs and led to a positive net benefit. For the larger aneurysms (4.5-5.4 cm), increasing surveillance intervals from 3 to 6 months led to equivalent cost-effectiveness.
There were no clear reasons why the growth rates varied substantially between studies. Uniform diagnostic criteria for rupture were not available. The long-term cost-effectiveness results may be susceptible to the modelling assumptions made.
Surveillance intervals of several years are clinically acceptable for men with AAAs in the range 3.0-4.0 cm. Intervals of around 1 year are suitable for 4.0-4.9-cm AAAs, whereas intervals of 6 months would be acceptable for 5.0-5.4-cm AAAs. These intervals are longer than those currently employed in the UK AAA screening programmes. Lengthening surveillance intervals for the smallest aneurysms was also shown to be cost-effective. Future work should focus on optimising surveillance intervals for women, studying whether or not the threshold for surgery should depend on patient characteristics, evaluating the usefulness of surveillance for those with aortic diameters of 2.5-2.9 cm, and developing interventions that may reduce the growth or rupture rates of small AAAs.
The National Institute for Health Research Health Technology Assessment programme.
To assess the clinical effectiveness and cost-effectiveness of endosonography (followed by surgical staging if endosonography was negative), compared with standard surgical staging alone, in patients ...with non-small cell lung cancer (NSCLC) who are otherwise candidates for surgery with curative intent.
A prospective, international, open-label, randomised controlled study, with a trial-based economic analysis.
Four centres: Ghent University Hospital, Belgium; Leuven University Hospitals, Belgium; Leiden University Medical Centre, the Netherlands; and Papworth Hospital, UK.
known/suspected NSCLC, with suspected mediastinal lymph node involvement; otherwise eligible for surgery with curative intent; clinically fit for endosonography and surgery; and no evidence of metastatic disease.
previous lung cancer treatment; concurrent malignancy; uncorrected coagulopathy; and not suitable for surgical staging.
Study patients were randomised to either surgical staging alone (n = 118) or endosonography followed by surgical staging if endosonography was negative (n = 123). Endosonography diagnostic strategy used endoscopic ultrasound-guided fine-needle aspiration combined with endobronchial ultrasound-guided transbronchial needle aspiration, followed by surgical staging if these tests were negative. Patients with no evidence of mediastinal metastases or tumour invasion were referred for surgery with curative intent. If evidence of malignancy was found, patients were referred for chemoradiotherapy.
The main clinical outcomes were sensitivity (positive diagnostic test/nodal involvement during any diagnostic test or thoracotomy) and negative predictive value (NPV) of each diagnostic strategy for the detection of N2/N3 metastases, unnecessary thoracotomy and complication rates. The primary economic outcome was cost-utility of the endosonography strategy compared with surgical staging alone, up to 6 months after randomisation, from a UK NHS perspective.
Clinical and resource-use data were available for all 241 patients, and complete utilities were available for 144. Sensitivity for detecting N2/N3 metastases was 79% 41/52; 95% confidence interval (CI) 66% to 88% for the surgical arm compared with 94% (62/66; 95% CI 85% to 98%) for the endosonography strategy (p = 0.02). Corresponding NPVs were 86% (66/77; 95% CI 76% to 92%) and 93% (57/61; 95% CI 84% to 97%; p = 0.26). There were 21/118 (18%) unnecessary thoracotomies in the surgical arm compared with 9/123 (7%) in the endosonography arm (p = 0.02). Complications occurred in 7/118 (6%) in the surgical arm and 6/123 (5%) in the endosonography arm (p = 0.78): one pneumothorax related to endosonography and 12 complications related to surgical staging. Patients in the endosonography arm had greater EQ-5D (European Quality of Life-5 Dimensions) utility at the end of staging (0.117; 95% CI 0.042 to 0.192; p = 0.003). There were no other significant differences in utility. The main difference in resource use was the number of thoracotomies: 66% patients in the surgical arm compared with 53% in the endosonography arm. Resource use was similar between the groups in all other items. The 6-month cost of the endosonography strategy was £9713 (95% CI £7209 to £13,307) per patient versus £10,459 (£7732 to £13,890) for the surgical arm, mean difference £746 (95% CI -£756 to £2494). The mean difference in quality-adjusted life-year was 0.015 (95% CI -0.023 to 0.052) in favour of endosonography, so this strategy was cheaper and more effective.
Endosonography (followed by surgical staging if negative) had higher sensitivity and NPVs, resulted in fewer unnecessary thoracotomies and better quality of life during staging, and was slightly more effective and less expensive than surgical staging alone. Future work could investigate the need for confirmatory mediastinoscopy following negative endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), the diagnostic accuracy of EUS-FNA or EBUS-TBNA separately and the delivery of both EUS-FNA or EBUS-TBNA by suitably trained chest physicians.
Current Controlled Trials ISRCTN 97311620.
This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 16, No. 18. See the HTA programme website for further project information.
If conservation priority birds are to persist in an increasingly anthropogenically altered world, suitable habitat must be created or preserved in potentially unsuitable landscapes. While natural ...areas in urban environments may provide habitat for declining groups of birds, little is known about effects of urbanization on the reproductive success of birds, such as grassland birds, that are typically thought to be associated with more rural landscapes. While typical conservation efforts have focused on conserving large patches of grassland in landscapes containing minimal amounts of woody vegetation and development, the assumption that habitat located in developed landscapes is of poor quality has not been tested and may wrongly devalue grasslands located in an urban matrix. To examine the influence of development on habitat quality for grassland birds, we studied grassland bird nest predation and brood parasitism in patches of varying size along an urbanization gradient in northeastern Illinois. Because nest predation is the primary cause of reproductive failure and a potentially limiting factor for grassland bird populations, we used miniature video cameras to identify predators at a subset of nests. From 2012 to 2013, we monitored 432 nests of 16 grassland bird species. Nest predation rates decreased with urbanization in the landscape as did probability of brood parasitism. We filmed 44 nests and documented 19 predation events. We found that coyotes Canis latrans, white‐tailed deer Odocoileus virginianus and thirteen‐lined ground squirrels Ictidomys tridecemlineatus were important nest predators in our study system. Contrary to prior assumptions, our results suggest that grasslands located in urban landscapes may provide habitat of equal or greater quality than many rural grasslands.
In this paper, we show how a dense surface point distribution model of the human face can be computed and demonstrate the usefulness of the high-dimensional shape-space for expressing the shape ...changes associated with growth and aging. We show how average growth trajectories for the human face can be computed in the absence of longitudinal data by using kernel smoothing across a population. A training set of three-dimensional surface scans of 199 male and 201 female subjects of between 0 and 50 years of age is used to build the model.
Exercise presents a considerable stress to the pulmonary system and ventilation-perfusion (Va/Q) heterogeneity increases with exercise, affecting the efficiency of gas exchange. In particular, ...prolonged heavy exercise and maximal exercise are known to increase Va/Q heterogeneity and these changes persist into recovery. We hypothesized that the spatial heterogeneity of pulmonary perfusion would be similarly elevated after prolonged exercise. To test this, athletic subjects (n = 6, Vo(2max) = 61 ml. kg(-1).min(-1)) with exercising Va/Q heterogeneity previously characterized by the multiple inert gas elimination technique (MIGET), performed 45 min of cycle exercise at approximately 70% Vo(2max). MRI arterial spin labeling measures of pulmonary perfusion were acquired pre- and postexercise (at 20, 40, 60 min post) to quantify the spatial distribution in isogravitational (coronal) and gravitationally dependent (sagittal) planes. Regional proton density measurements allowed perfusion to be normalized for density and quantified in milliliters per minute per gram. Mean lung density did not change significantly in either plane after exercise (P = 0.19). Density-normalized perfusion increased in the sagittal plane postexercise (P =or <0.01) but heterogeneity did not (all P >or= 0.18), likely because of perfusion redistribution and vascular recruitment. Density-normalized perfusion was unchanged in the coronal plane postexercise (P = 0.66), however, perfusion heterogeneity was significantly increased as measured by the relative dispersion RD, pre 0.62(0.07), post 0.82(0.21), P < 0.0001 and geometric standard deviation GSD, pre 1.74(0.14), post 2.30(0.56), P < 0.005. These changes in heterogeneity were related to the exercise-induced changes of the log standard deviation of the ventilation distribution, an MIGET index of Va/Q heterogeneity (RD R(2) = 0.68, P < 0.05, GSD, R(2) = 0.55, P = 0.09). These data are consistent with but not proof of interstitial pulmonary edema as the mechanism underlying exercise-induced increases in both spatial perfusion heterogeneity and Va/Q heterogeneity.
We hypothesized that some of the heterogeneity of pulmonary blood flow present in the normal human lung in normoxia is due to hypoxic pulmonary vasoconstriction (HPV). If so, mild hyperoxia would ...decrease the heterogeneity of pulmonary perfusion, whereas it would be increased by mild hypoxia. To test this, six healthy nonsmoking subjects underwent magnetic resonance imaging (MRI) during 20 min of breathing different oxygen concentrations through a face mask normoxia, inspired O(2) fraction (Fi(O(2))) = 0.21; hypoxia, Fi(O(2)) = 0.125; hyperoxia, Fi(O(2)) = 0.30 in balanced order. Data were acquired on a 1.5-T MRI scanner during a breath hold at functional residual capacity from both coronal and sagittal slices in the right lung. Arterial spin labeling was used to quantify the spatial distribution of pulmonary blood flow in milliliters per minute per cubic centimeter and fast low-angle shot to quantify the regional proton density, allowing perfusion to be expressed as density-normalized perfusion in milliliters per minute per gram. Neither mean proton density hypoxia, 0.46(0.18) g water/cm(3); normoxia, 0.47(0.18) g water/cm(3); hyperoxia, 0.48(0.17) g water/cm(3); P = 0.28 nor mean density-normalized perfusion hypoxia, 4.89(2.13) ml x min(-1) x g(-1); normoxia, 4.94(1.88) ml x min(-1) x g(-1); hyperoxia, 5.32(1.83) ml x min(-1) x g(-1); P = 0.72 were significantly different between conditions in either imaging plane. Similarly, perfusion heterogeneity as measured by relative dispersion hypoxia, 0.74(0.16); normoxia, 0.74(0.10); hyperoxia, 0.76(0.18); P = 0.97, fractal dimension hypoxia, 1.21(0.04); normoxia, 1.19(0.03); hyperoxia, 1.20(0.04); P = 0.07, log normal shape parameter hypoxia, 0.62(0.11); normoxia, 0.72(0.11); hyperoxia, 0.70(0.13); P = 0.07, and geometric standard deviation hypoxia, 1.88(0.20); normoxia, 2.07(0.24); hyperoxia, 2.02(0.28); P = 0.11 was also not different. We conclude that HPV does not affect pulmonary perfusion heterogeneity in normoxia in the normal supine human lung.
Standardised histological criteria are now available for the diagnosis of canine chronic hepatitis (CH). CH is common in dogs, but no studies have reported breed, age and gender distributions in the ...United Kingdom (UK). The objective of this study was to determine which breeds had an increased risk for developing CH in the UK and to report the age and gender distribution for those breeds. The databases of six veterinary histopathology laboratories were searched for cases with a histological diagnosis of CH according to standardised criteria. The breed, age and gender of dogs was recorded and compared to a control population to calculate the odds ratio and 95% confidence intervals for developing CH.
A total of 551 cases of CH were identified, consisting of 61 breeds. Nineteen breeds were represented by five or more cases. Breeds with an increased risk for developing CH included the American cocker spaniel, Cairn terrier, Dalmatian, Dobermann pinscher, English cocker spaniel, English springer spaniel, Great Dane, Labrador retriever and Samoyed. The median age at diagnosis for all breeds with CH was 8years (range 7months to 16years). Dalmatians, Dobermann pinschers and English springer spaniels with CH were significantly younger than Cairn terriers, English cocker spaniels and Labrador retrievers with CH. Females were over-represented when all cases were examined together. In conclusion, several breeds in the UK have an increased risk of CH, some of which have not been previously reported.
Neospora caninum is a protozoan parasite of animals, which before 1984 was misidentified as Toxoplasma gondii. Infection by this parasite is a major cause of abortion in cattle and causes paralysis ...in dogs. Since the original description of N. caninum in 1988, considerable progress has been made in the understanding of its life cycle, biology, genetics and diagnosis. In this article, the authors redescribe the parasite, distinguish it from related coccidia, and provide accession numbers to its type specimens deposited in museums.
Few data are available on the long-term outcome of endovascular repair of abdominal aortic aneurysm as compared with open repair.
From 1999 through 2004 at 37 hospitals in the United Kingdom, we ...randomly assigned 1252 patients with large abdominal aortic aneurysms (> or = 5.5 cm in diameter) to undergo either endovascular or open repair; 626 patients were assigned to each group. Patients were followed for rates of death, graft-related complications, reinterventions, and resource use until the end of 2009. Logistic regression and Cox regression were used to compare outcomes in the two groups.
The 30-day operative mortality was 1.8% in the endovascular-repair group and 4.3% in the open-repair group (adjusted odds ratio for endovascular repair as compared with open repair, 0.39; 95% confidence interval CI, 0.18 to 0.87; P=0.02). The endovascular-repair group had an early benefit with respect to aneurysm-related mortality, but the benefit was lost by the end of the study, at least partially because of fatal endograft ruptures (adjusted hazard ratio, 0.92; 95% CI, 0.57 to 1.49; P=0.73). By the end of follow-up, there was no significant difference between the two groups in the rate of death from any cause (adjusted hazard ratio, 1.03; 95% CI, 0.86 to 1.23; P=0.72). The rates of graft-related complications and reinterventions were higher with endovascular repair, and new complications occurred up to 8 years after randomization, contributing to higher overall costs.
In this large, randomized trial, endovascular repair of abdominal aortic aneurysm was associated with a significantly lower operative mortality than open surgical repair. However, no differences were seen in total mortality or aneurysm-related mortality in the long term. Endovascular repair was associated with increased rates of graft-related complications and reinterventions and was more costly. (Current Controlled Trials number, ISRCTN55703451.)
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