Systematic review and meta-analysis of the growth and rupture rates of small abdominal aortic aneurysms: implications for surveillance intervals and their cost-effectiveness.

BACKGROUND: 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. OBJECTIVES: 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. DATA SOURCES: 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. REVIEW METHODS: 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. RESULTS: 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. LIMITATIONS: 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. CONCLUSIONS: 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. FUNDING: The National Institute for Health Research Health Technology Assessment programme

Patient anxiety and conscious surgery

The amount of surgery undertaken on the conscious patient is increasing. However, many patients are anxious and resistant to such surgery. Patients (n=214) were surveyed to determine their related apprehensions. Being awake, feeling or seeing the body cut open and experiencing pain all increased anxiety. The potential for insufficient information provision was also a source of concern. Formal management of intra-operative apprehension may help limit anxiety and expel apparent misapprehensions

Open secrets

The law of trade secrets is often conceptualized in bilateral terms, as creating and enforcing rights between trade secret owners, on the one hand, and misappropriators on the other hand. This paper, a chapter in a forthcoming collection on the law of trade secrets, argues that trade secrets and the law that guards them can serve structural and institutional roles as well. Somewhat surprisingly, given the law’s focus on secrecy, among the institutional products of trade secrets law are commons, or managed openness: environments designed to facilitate the structured sharing of information. The paper illustrates with examples drawn from existing literature on cuisine, magic, and Internet search.

'Black Phones': postmodern poetics in the Holocaust poetry of Sylvia Plath

This essay offers a fresh perspective on the Holocaust verse of the American poet Sylvia Plath, taking issue with the accusation that in her poetry she uses the Holocaust as a metaphor to figure her own personal pain. This essay offers close readings of the eccentric monologue 'Lady Lazarus' and the 'German trilogy' of 'Little Fugue', 'Daddy' and 'The Munich Mannequins'. Paying particular attention to the recurring motif of the 'black phone', this essay argues that Plath's Holocaust verse offers a self-aware response to the genocide that is identifiably postmodern in its innovative, self-reflexive treatment of history

Cannon-Thurston Maps,i-bounded Geometry and a theorem of McMullen

The notion of i-bounded geometry generalises simultaneously bounded geometry and the geometry of punctured torus Kleinian groups. We show that the limit set of a surface Kleinian group of i-bounded geometry is locally connected by constructing a natural Cannon-Thurston map. This is an exposition of a special case of the main result of arXiv:math/0607509.Comment: v3: 32 pages 3 figure

Day surgery and general anaesthesia : what makes patients anxious?

For many patients the prospective of undergoing surgery and general anaesthesia is highly anxiety provoking. With the global rise in day surgery and limited nurse/ patient contact, anxiety has become a prominent issue. The aim of the study was to establish the degree of anxiety arising from elective day surgery and general anaesthesia and uncover specific anxiety provoking aspects. Day surgery patients (n=460) completed a questionnaire during recovery at home and return it by post. The majority of patients (85%) were anxious on the day of surgery and 50% desired a detailed level of information. Anaesthetic information provision, catastrophising and imminence of surgery were deemed to be reliable predictors of anxiety. The planned provision of anaesthetic information in advance of the day of surgery, emphasising ‘controlled unconsciousness’, provision of information to help limit catastrophising thoughts and assistance to reduce the impact of ‘waiting’ are recommended for the effective management of anxiety