Mechanical properties of suprarenal and infrarenal abdominal aorta: implications for mouse models of aneurysms

Multiple mouse models have been developed to increase our understanding of the natural history of abdominal aortic aneurysms. An advantage of such models is that one can quantify the time course of changes in geometry, histology, cell biology, and mechanics as a lesion develops. One of the most commonly used mouse models yields lesions in the suprarenal abdominal aorta whereas most other models target the infrarenal abdominal aorta, consistent with the clinical observation that nearly all abdominal aneurysms in humans occur in the infrarenal aorta. Understanding reasons for similarities and differences between diverse mouse models and human lesions may provide increased insight that would not be possible studying a single situation alone. Toward this end, however, we must first compare directly the native structure and properties of these two portions of the abdominal aorta in the mouse. In this paper, we present the first biaxial mechanical data and nonlinear constitutive descriptors for the suprarenal and infrarenal aorta in mice, which reveals only subtle mechanical differences despite marked morphological and histological differences. Such data promise to increase our ability to understand and model the natural history of these deadly lesions.

Tobacco smoking in seven Latin American cities: the CARMELA study

Objective

This study aimed to explore tobacco smoking in seven major cities of Latin America.

Methods

The Cardiovascular Risk Factor Multiple Evaluation in Latin America (CARMELA) study is a cross-sectional epidemiological study of 11 550 adults between 25 and 64 years old in Barquisimeto, Venezuela; Bogota, Colombia; Buenos Aires, Argentina; Lima, Peru; Mexico City, Mexico; Quito, Ecuador; and Santiago, Chile. Tobacco smoking, including cigarettes, cigars and pipes, was surveyed among other cardiovascular risk factors.

Results

Santiago and Buenos Aires had the highest smoking prevalence (45.4% and 38.6%, respectively); male and female rates were similar. In other cities, men smoked more than women, most markedly in Quito (49.4% of men vs 10.5% of women). Peak male smoking prevalence occurred among the youngest two age groups (25–34 and 35–44 years old). Men and women of Buenos Aires smoked the highest number of cigarettes per day on average (15.7 and 12.4, respectively). Men initiated regular smoking earlier than women in each city (ranges 13.7–20.0 years vs 14.2–21.1 years, respectively). Exposure to secondhand tobacco smoke at workplace for more than 5 h per day was higher in Barquisimeto (28.7%), Buenos Aires (26.8%) and Santiago (21.5%). The highest prevalence of former smokers was found among men in Buenos Aires, Santiago and Lima (30.0%, 26.8% and 26.0% respectively).

Conclusions

Smoking prevalence was high in the seven CARMELA cities, although patterns of smoking varied among cities. A major health and economic burden is inevitable in urban Latin America unless effective comprehensive tobacco control measures recommended by the World Health Organisation Framework Convention on Tobacco Control are implemented.

Biodiversity studies: science and policy

Biodiversity studies comprise the systematic examination of the full array of different kinds of organisms together with the technology by which the diversity can be maintained and used for the benefit of humanity. Current basic research at the species level focuses on the process of species formation, the standing levels of species numbers in various higher taxonomic categories, and the phenomena of hyperdiversity and extinction proneness. The major practical concern is the massive extinction rate now caused by human activity, which threatens losses in the esthetic quality of the world, in economic opportunity, and in vital ecosystem services.

Meta-analysis of randomized controlled trials on the safety and effectiveness of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

The original article to which this Erratum refers was published in British Journal of Surgery 2010; 97: 141–150.

Meta-analysis of randomized controlled trials on the safety and effectiveness of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

: In many countries laparoscopic cholecystectomy for acute cholecystitis is mainly performed after the acute episode has settled because of the anticipated increased risk of morbidity and higher conversion rate from laparoscopic to open cholecystectomy.

METHODS

: A systematic review was performed with meta-analysis of randomized clinical trials of early laparoscopic cholecystectomy (ELC; performed within 1 week of onset of symptoms) versus delayed laparoscopic cholecystectomy (performed at least 6 weeks after symptoms settled) for acute cholecystitis. Trials were identified from The Cochrane Library trials register, Medline, Embase, Science Citation Index Expanded and reference lists. Risk ratio (RR) or mean difference was calculated with 95 per cent confidence intervals (c.i.) based on intention-to-treat analysis.

RESULTS

: Five trials with 451 patients were included. There was no significant difference between the two groups in terms of bile duct injury (RR 0.64 (95 per cent c.i. 0.15 to 2.65)) or conversion to open cholecystectomy (RR 0.88 (95 per cent c.i. 0.62 to 1.25)). The total hospital stay was shorter by 4 days for ELC (mean difference -4.12 (95 per cent c.i. -5.22 to -3.03) days).

CONCLUSION

: ELC during acute cholecystitis appears safe and shortens the total hospital stay.

Cost-utility and value-of-information analysis of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

: A recent systematic review found early laparoscopic cholecystectomy (ELC) to be safe and to shorten total hospital stay compared with delayed laparoscopic cholecystectomy (DLC) for acute cholecystitis. The cost-effectiveness of ELC versus DLC for acute cholecystitis is unknown.

METHODS

: A decision tree model estimating and comparing costs to the UK National Health Service (NHS) and quality-adjusted life years (QALYs) gained following a policy of either ELC or DLC was developed with a time horizon of 1 year. Uncertainty was investigated with probabilistic sensitivity analysis, and value-of-information analysis estimated the likely return from further investment in research in this area.

RESULTS

: ELC is less costly (approximately - pound820 per patient) and results in better quality of life (+0.05 QALYs per patient) than DLC. Given a willingness-to-pay threshold of pound20 000 per QALY gained, there is a 70.9 per cent probability that ELC is cost effective compared with DLC. Full implementation of ELC could save the NHS pound8.5 million per annum.

CONCLUSION

: The results of this decision analytic modelling study suggest that on average ELC is less expensive and results in better quality of life than DLC. Future research should focus on quality-of-life measures alone.

The PRaCTICaL study of nurse led, intensive care follow-up programmes for improving long term outcomes from critical illness: a pragmatic randomised controlled trial

OBJECTIVES

To test the hypothesis that nurse led follow-up programmes are effective and cost effective in improving quality of life after discharge from intensive care.

DESIGN

A pragmatic, non-blinded, multicentre, randomised controlled trial.

SETTING

Three UK hospitals (two teaching hospitals and one district general hospital).

PARTICIPANTS

286 patients aged >or=18 years were recruited after discharge from intensive care between September 2006 and October 2007.

INTERVENTION

Nurse led intensive care follow-up programmes versus standard care. Main outcome measure(s) Health related quality of life (measured with the SF-36 questionnaire) at 12 months after randomisation. A cost effectiveness analysis was also performed.

RESULTS

286 patients were recruited and 192 completed one year follow-up. At 12 months, there was no evidence of a difference in the SF-36 physical component score (mean 42.0 (SD 10.6) v 40.8 (SD 11.9), effect size 1.1 (95% CI -1.9 to 4.2), P=0.46) or the SF-36 mental component score (effect size 0.4 (-3.0 to 3.7), P=0.83). There were no statistically significant differences in secondary outcomes or subgroup analyses. Follow-up programmes were significantly more costly than standard care and are unlikely to be considered cost effective.

CONCLUSIONS

A nurse led intensive care follow-up programme showed no evidence of being effective or cost effective in improving patients' quality of life in the year after discharge from intensive care. Further work should focus on the roles of early physical rehabilitation, delirium, cognitive dysfunction, and relatives in recovery from critical illness. Intensive care units should review their follow-up programmes in light of these results.

TRIAL REGISTRATION

ISRCTN 24294750.

Metastatic renal cell carcinoma presenting as a breast lump in a treated breast cancer patient

Metastatic malignancy in the breast is uncommon. A 68-year-old woman with a past medical history of breast cancer presented with a lump in the opposite breast. A mammogram suggested a possible benign lump. An ultrasonography-guided core needle biopsy was taken to complete the triple assessment. The histology on the breast core biopsy showed it to be a metastatic renal cell carcinoma. Subsequent computed tomography of the abdomen confirmed a renal primary tumour. The patient was referred to the renal oncologist for palliative treatment.

Does befriending by trained lay workers improve psychological well-being and quality of life for carers of people with dementia, and at what cost? A randomised controlled trial

OBJECTIVES

To determine whether a social support intervention (access to an employed befriending facilitator in addition to usual care) is effective compared with usual care alone. Also to document direct and indirect costs, and establish incremental cost-effectiveness.

DESIGN

The Befriending and Costs of Caring (BECCA) trial was a cost-effectiveness randomised controlled trial. Data on well-being and resource use were collected through interviews with participants at baseline and at 6, 15 and 24 months.

SETTING

This research was carried out in the English counties of Norfolk and Suffolk, and the London Borough of Havering. It was a community-based study.

PARTICIPANTS

Participants were family carers who were cohabiting with, or providing at least 20 hours' care per week for, a community-dwelling relative with a primary progressive dementia.

INTERVENTIONS

The intervention was 'access to a befriender facilitator' (BF). BFs, based with charitable/voluntary-sector organisations, were responsible for local befriending schemes, including recruitment, screening, training and ongoing support of befriending volunteers, and for matching carers with befrienders. The role of befrienders was to provide emotional support for carers. The target duration for befriending relationships was 6 months or more.

MAIN OUTCOME MEASURES

Depression was measured by the Hospital Anxiety and Depression Scale (HADS) at 15 months postrandomisation. The health-related quality of life scale EQ-5D (EuroQol 5 Dimensions) was used to derive utilities for the calculation of quality-adjusted life-years (QALYs).

RESULTS

A total of 236 carers were randomised into the trial (116 intervention; 120 control). At final follow-up, 190 carers (93 intervention; 97 control) were still involved in the trial (19% attrition). There was no evidence of effectiveness or cost-effectiveness from the primary analyses on the intention-to-treat population. The mean incremental cost per incremental QALY gained was in excess of 100,000 pounds, with only a 42.2% probability of being below 30,000 pounds per QALY gained. Where care-recipient QALYs were included, mean incremental cost per incremental QALY gained was 26,848 pounds, with a 51.4% probability of being below 30,000 pounds per QALY gained. Only 60 carers (52%) took up the offer of being matched with a trained lay befriender, and of these only 37 (32%) were befriended for 6 months or more. A subgroup analysis of controls versus those befriended for 6 months or more found a reduction in HADS-depression scores that approached statistical significance (95% CI -0.09 to 2.84).

CONCLUSIONS

'Access to a befriender facilitator' is neither an effective nor a cost-effective intervention in the support of carers of people with dementia, although there is a suggestion of cost-effectiveness for the care dyad (carer and care recipient). In common with many services for carers of people with dementia, uptake of befriending services was not high. However, the small number of carers who engaged with befrienders for 6 months or more reported a reduction in scores on HADS depression that approached statistical significance compared with controls (95% CI -0.09 to 2.84). While providing only weak evidence of any beneficial effect, further research into befriending interventions for carers is warranted.