The UK EndoVascular Aneurysm Repair (EVAR) trials: randomised trials of EVAR versus standard therapy

Understanding the pathogenesis of abdominal aortic aneurysms

An aortic aneurysm is a dilatation in which the aortic diameter is ≥3.0 cm. If left untreated, the aortic wall continues to weaken and becomes unable to withstand the forces of the luminal blood pressure resulting in progressive dilatation and rupture, a catastrophic event associated with a mortality of 50-80%. Smoking and positive family history are important risk factors for the development of abdominal aortic aneurysms (AAA). Several genetic risk factors have also been identified. On the histological level, visible hallmarks of AAA pathogenesis include inflammation, smooth muscle cell apoptosis, extracellular matrix degradation and oxidative stress. We expect that large genetic, genomic, epigenetic, proteomic and metabolomic studies will be undertaken by international consortia to identify additional risk factors and biomarkers, and to enhance our understanding of the pathobiology of AAA. Collaboration between different research groups will be important in overcoming the challenges to develop pharmacological treatments for AAA.

Juxtarenal Modular Aortic Stent Graft Infection Caused by Staphylococcus aureus

Introduction. We are presenting a case report of an infected modular abdominal stent graft. Case Presentation. A 67-year-old male patient three years after Cook's modular abdominal aortic aneurysm (AAA) graft implantation for juxtarenal AAA with an implantation of a stent extension into the right common iliac artery for type Ib endoleak. The patient was admitted into our center in severe condition with suspected retroperitoneal bleeding. Computed tomography angiography (CTAG) confirmed retroperitoneal bleeding in the right common iliac artery. An urgent surgical revision was indicated; destructed arterial wall around the stent extension in the right common iliac artery was discovered. Due to the severe state of health of the patient, a resection of the infected stent and affected arterial wall was performed, followed by an iliac-femoral crossover bypass. The patient was transported to the intensive care unit with hepatic and renal failure, with maximal catecholamine support. Combined antibiotic treatment was started. The patient died five hours after the procedure. The cause of death was multiorgan failure caused by sepsis. Hemocultures and perioperative microbiological cultures showed the infection agent to be Staphylococcus aureus methicillin sensitive. Conclusion. Stent graft infection is a rare complication. Treatment is associated with high mortality and morbidity.

Endovascular repair or open repair for ruptured abdominal aortic aneurysm: a Cochrane systematic review

OBJECTIVES

Emergency endovascular aneurysm repair (eEVAR) may improve outcomes for patients with ruptured abdominal aortic aneurysm (RAAA). The study aim was to compare the outcomes for eEVAR with conventional open surgical repair for the treatment of RAAA.

SETTING

A systematic review of relevant publications was performed. Randomised controlled trials (RCTs) comparing eEVAR with open surgical repair for RAAA were included.

PARTICIPANTS

3 RCTs were included, with a total of 761 patients with RAAA.

INTERVENTIONS

Meta-analysis was performed with fixed-effects models with ORs and 95% CIs for dichotomous data and mean differences with 95% CIs for continuous data.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was short-term mortality. Secondary outcome measures included aneurysm-specific and general complication rates, quality of life and economic analysis.

RESULTS

Overall risk of bias was low. There was no difference between the 2 interventions on 30-day (or in-hospital) mortality, OR 0.91 (95% CI 0.67 to 1.22; p=0.52). 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, reoperation, amputation and respiratory failure. Reporting was incomplete, and no robust conclusion was drawn. For complication outcomes that did include at least 2 studies in the meta-analysis, there was no clear evidence to support a difference between eEVAR and open repair. Longer term outcomes and cost per patient were evaluated in only a single study, thus precluding definite conclusions.

CONCLUSIONS

Outcomes between eEVAR and open repair, specifically 30-day mortality, are similar. However, further high-quality trials are required, as the paucity of data currently limits the conclusions.

Endovascular Aneurysm Sealing Is Associated With Reduced Radiation Exposure and Procedure Time Compared With Standard Endovascular Aneurysm Repair

Purpose: To compare indirect measures of radiation exposure and operating time between endovascular aneurysm sealing (EVAS) and endovascular aneurysm repair (EVAR) for the treatment of abdominal aortic aneurysm (AAA). Methods: The study compared 32 consecutive patients (mean age 78 years; 21 men) with AAA who underwent standard EVAS with 32 consecutive patients (mean age 78 years; 25 men) treated with EVAR between November 2013 and May 2015. Electronic medical records and image archiving databases were interrogated to retrieve relevant information and scans. Screening time and dose area product (DAP) were the primary outcome measures. Data are presented as median and interquartile range (IQR). Correlations were tested with the Spearman rank coefficient (ρ). Results: The screening time was shorter in EVAS than in EVAR [16 (IQR 14, 20) vs 32 (IQR 26, 38) minutes; p<0.001]. DAP was lower in EVAS than in EVAR [54 (IQR 42, 77) vs 111 (IQR 75, 157) Gy∙cm2; p<0.001]. Digital subtraction angiography delivered 20% (IQR 15%, 28%) of the DAP in EVAS compared with 14% (IQR 11%, 19%) in EVAR (p<0.001), but the absolute time used on digital subtraction was marginally lower in EVAS than in EVAR [1.07 (IQR 0.52, 1.23) vs 1.19 (IQR 0.70, 1.39) minutes; p=0.037]. The operating time was shorter for EVAS [121 (IQR 105, 146) vs 162 (IQR 145,186) minutes; p<0.001]. There was a moderate correlation between DAP and screening time (ρ=0.597, p<0.001), fluoroscopy time (ρ=0.595, p<0.001), digital subtraction time (ρ=0.301, p=0.015), and operating time (ρ=0.512, p<0.001). Conclusion: EVAS is associated with reduced radiation exposure and operating room usage compared with EVAR, which may have safety and financial implications.

Calculating when elective abdominal aortic aneurysm repair improves survival for individual patients: development of the Aneurysm Repair Decision Aid and economic evaluation

BACKGROUND

Abdominal aortic aneurysm (AAA) repair aims to prevent premature death from AAA rupture. Elective repair is currently recommended when AAA diameter reaches 5.5 cm (men) and 5.0 cm (women). Applying population-based indications may not be appropriate for individual patient decisions, as the optimal indication is likely to differ between patients based on age and comorbidities.

OBJECTIVE

To develop an Aneurysm Repair Decision Aid (ARDA) to indicate when elective AAA repair optimises survival for individual patients and to assess the cost-effectiveness and associated uncertainty of elective repair at the aneurysm diameter recommended by the ARDA compared with current practice.

DATA SOURCES

The UK Vascular Governance North West and National Vascular Database provided individual patient data to develop predictive models for perioperative mortality and survival. Data from published literature were used to model AAA growth and risk of rupture. The cost-effectiveness analysis used data from published literature and from local and national databases.

METHODS

A combination of systematic review methods and clinical registries were used to provide data to populate models and inform the structure of the ARDA. Discrete event simulation (DES) was used to model the patient journey from diagnosis to death and synthesised data were used to estimate patient outcomes and costs for elective repair at alternative aneurysm diameters. Eight patient clinical scenarios (vignettes) were used as exemplars. The DES structure was validated by clinical and statistical experts. The economic evaluation estimated costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) from the NHS, social care provider and patient perspective over a lifetime horizon. Cost-effectiveness acceptability analyses and probabilistic sensitivity analyses explored uncertainty in the data and the value for money of ARDA-based decisions. The ARDA outcome measures include perioperative mortality risk, annual risk of rupture, 1-, 5- and 10-year survival, postoperative long-term survival, median life expectancy and predicted time to current threshold for aneurysm repair. The primary economic measure was the ICER using the QALY as the measure of health benefit.

RESULTS

The analysis demonstrated it is feasible to build and run a complex clinical decision aid using DES. The model results support current guidelines for most vignettes but suggest that earlier repair may be effective in younger, fitter patients and ongoing surveillance may be effective in elderly patients with comorbidities. The model adds information to support decisions for patients with aneurysms outside current indications. The economic evaluation suggests that using the ARDA compared with current guidelines could be cost-effective but there is a high level of uncertainty.

LIMITATIONS

Lack of high-quality long-term data to populate all sections of the model meant that there is high uncertainty about the long-term clinical and economic consequences of repair. Modelling assumptions were necessary and the developed survival models require external validation.

CONCLUSIONS

The ARDA provides detailed information on the potential consequences of AAA repair or a decision not to repair that may be helpful to vascular surgeons and their patients in reaching informed decisions. Further research is required to reduce uncertainty about key data, including reintervention following AAA repair, and assess the acceptability and feasibility of the ARDA for use in routine clinical practice.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

[Endovascular versus conventional vascular surgery - old-fashioned thinking? Part 1: interventions on the aorta]

Endovascular therapy has widely replaced conventional open vascular surgical reconstruction. For this reason both techniques were widely considered to be competing approaches. Evidence-based data from randomized prospective trials, meta-analyses and clinical registries, however, demonstrated that both techniques should be used to complement each other. It became increasingly more evident that the use of either procedure depends on the underlying disease and the anatomical conditions, whereby a combination of both (hybrid approach) may be the preferred option in certain situations. This review focuses on the treatment of complicated acute type B aortic dissection, descending thoracic aortic aneurysms, thoracoabdominal aortic aneurysms as well as asymptomatic and ruptured abdominal aortic aneurysms.

One Year Experience of Iliac Bifurcated Device for Aortoiliac Aneurysm in a Korean Single Center

One of the predominant methods for preserving the internal iliac artery (IIA) in aortoiliac aneurysms is to use an iliac bifurcated device (IBD). However, there are a few limitations to the use of IBD in Korea. Our study aims to present the technical aspects of these devices, and to provide a mid-term analysis of IBD. Since 2013, 4 IBDs were used in 4 patients, with a mean follow-up of 14 months (range, 6-22 months). A 100% technical success rate was achieved without mortality and morbidity in our cases. The mean procedural time was 176 min (range, 145-240 min), and the mean contrast dose used was 184 mL (range, 135-220 mL). Type I or III endoleaks and postoperative expansion of the aneurysms weren't observed. Our cases demonstrates that IBD is a relatively safe repair method of aortoiliac aneurysms with preservation of the IIAs. However, a longer follow-up is needed to review the midterm results.

Stent graft types for endovascular repair of abdominal aortic aneurysms

BACKGROUND

The UK prevalence of abdominal aortic aneurysm (AAA) is estimated at 4.9% in over 65-year olds. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of AAAs involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market. This is an update of the review first published in 2013.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of AAA.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2015) and the Cochrane Register of Studies (2015, Issue 1). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of AAAs were sought without language restriction and in consultation with the Cochrane Vascular Group TSC.

DATA COLLECTION AND ANALYSIS

We planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria. It was not possible to review the quality of the evidence in the absence of studies eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. High quality randomised controlled trials evaluating stent graft types in abdominal endovascular aneurysm repair are required.

The use of fenestrated and branched endovascular aneurysm repair for juxtarenal and thoracoabdominal aneurysms: a systematic review and cost-effectiveness analysis

BACKGROUND

Patients with large abdominal aortic aneurysms (AAAs) are usually offered reparative treatment given the high mortality risk. There is uncertainty about how to treat juxtarenal AAAs (JRAAAs) or thoracoabdominal aortic aneurysms (TAAAs). Endovascular repair of an abdominal aortic aneurysm (EVAR) is often seen as safer and easier than open surgical repair (OSR). However, endovascular treatment of JRAAAs or TAAAs requires specially manufactured stent grafts, with openings to allow blood to reach branches of the aorta. Commissioners are receiving increasing requests for fenestrated EVAR (fEVAR) and branched EVAR (bEVAR), but it is unclear whether or not the extra cost of fEVAR or bEVAR is justified by advantages for patients.

OBJECTIVE(S)

To assess the clinical effectiveness, safety and cost-effectiveness of fEVAR and bEVAR in comparison with conventional treatment (i.e. no surgery) or OSR for two populations: JRAAAs and TAAAs.

DATA SOURCES

Resources were searched from inception to October 2013, including MEDLINE (OvidSP), EMBASE (OvidSP) and the Cochrane Central Register of Controlled Trials (Wiley) and, additionally, for cost-effectiveness, NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost). Conference abstracts were also searched.

REVIEW METHODS

Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative, i.e. explicitly selected on the basis of prognosis.

RESULTS

For clinical effectiveness, searches retrieved 5253 records before deduplication. Owing to overlap between the databases, 1985 duplicate records were removed. Of the remaining 3268 records, based on titles and abstracts, 3244 records were excluded, leaving 24 publications to be ordered. All 24 studies were excluded as none of them satisfied the inclusion criteria. Sixteen studies were excluded on study design, six on intervention and two on comparator. Five out of 16 studies excluded on study design reported a comparison. However, all of the studies acknowledged that they had groups that were not comparable at baseline given that they had selectively assigned younger, fitter patients to OSR. Therefore, these studies were considered 'non-comparative'. For cost-effectiveness, searches identified 104 references before deduplication. Owing to overlap between the databases, 34 duplicate records were removed. Of the remaining 70 records, seven were included for the full assessment based on initial screening. After a full-text review, no studies were included. Because of the lack of clinical effectiveness evidence and difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead a detailed description of modelling methods was provided.

CONCLUSIONS

Despite a thorough search, no studies could be found that met the inclusion criteria. All studies that compared either fEVAR or bEVAR with either OSR or no surgery explicitly selected patients based on prognosis, i.e. essentially the populations for each comparator were not the same. Despite not being able to conduct a CEA, we have provided detailed methods for the conduct if data becomes available.

FUTURE WORK

We recommend at least one clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery. This trial should also collect data for a CEA.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006051.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Population-Based Study of Incidence of Acute Abdominal Aortic Aneurysms With Projected Impact of Screening Strategy

BACKGROUND

Current abdominal aortic aneurysm (AAA) screening in men age 65 might have limited impact on overall AAA death rates if incidence is moving to older ages. Up-to-date population-based studies of age-specific incidence, risk factors, and outcome of acute AAA are needed to inform screening policy.

METHODS AND RESULTS

In a prospective, population-based study (Oxfordshire, UK, 2002-2014), the incidence and outcome of acute AAA events were determined. Based on population projections and current incidence trends, the impact of screening strategies in the UK was estimated. Over the 12-year period, 103 incident acute AAA events occurred in the study population of 92 728. Incidence/100 000/year was 55 in men ages 65 to 74 years, but increased to 112 at 75 to 85 and 298 at ≥85, with 66.0% of all events occurring at age ≥75 years. Incidence at ages 65 to 74 was highest in male smokers (274), with 96.4% of events in men <75 years occurring in ever-smokers. Extrapolating rates to the UK population, using trial evidence of screening efficacy, the current UK screening program would prevent 5.6% of aneurysm-related deaths (315 200 scans/year: 1426/death prevented, 121/year-of-life saved). Screening only male smokers age 65 and then all men at age 75 would prevent 21.1% of deaths (247 900 scans/year; 297/death prevented, 34/year-of-life saved). By 2030, 91.0% of deaths will occur at age ≥75, 61.6% at ≥85, and 28.6% in women.

CONCLUSIONS

Given that two thirds of acute AAA occurred at ≥75 years of age, screening older age groups should be considered. Screening nonsmokers at age 65 is likely to have very little impact on AAA event rates.

The role of cost-effectiveness for vascular surgery service provision in the United Kingdom

OBJECTIVE

The cost of health care is increasingly becoming an international issue, with many health care systems requiring evaluation of cost when agreeing to fund health care. In the United Kingdom (UK), for example, the National Institute for Health and Care Excellence highlights the importance of using cost-effectiveness analyses to facilitate the effective use of resources. This study evaluates the use of cost-effectiveness analyses and the provision of vascular surgery.

METHODS

A systematic review of published literature was performed. UK-based studies assessing cost-effectiveness or cost-utility of superficial venous interventions, abdominal aortic aneurysm (AAA) repair, and carotid endarterectomy (CEA) were included. All included studies were quality assessed to determine the overall strength of UK economic evidence for each intervention.

RESULTS

Four superficial venous, six AAA, and two CEA studies met the inclusion criteria. After quality assessment, the UK evidence supporting the cost-effectiveness of superficial venous intervention was graded strong. The economic evidence for asymptomatic and symptomatic CEA was graded limited and insufficient, respectively, owing to a paucity of UK literature in this field. There was strong UK economic evidence affirming that endovascular aneurysm repair (EVAR) is unlikely to be a cost-effective alternative to open repair.

CONCLUSIONS

There is strong economic evidence for symptomatic superficial venous intervention. However, funding for varicose vein treatments remains controversial. Future economic analyses are required for symptomatic and asymptomatic CEA to better advise national policy. Despite strong economic evidence, current UK guidance is for EVAR over open repair in the elective setting, with the majority of elective AAA repairs being EVAR.

Non-invasive in vivo time-dependent strain measurement method in human abdominal aortic aneurysms: Towards a novel approach to rupture risk estimation

We aim to introduce a novel, inverse method for in vivo material parameter identification of human abdominal aortic aneurysms (AAA), which could overcome one of the greatest sources of uncertainty in patient-specific simulations, and could also serve as a rapid, patient-calibrated, novel measure of aneurysm rupture risk. As an initial step, the determination of the kinematic fields is presented here. Images of the AAA lumen, acquired in 10 discrete time-steps through a stabilized cardiac cycle by electrocardiogram-gated computer tomography angiography, are used to approximate the in vivo, time dependent kinematic fields of the arterial wall using a novel, incompressible Kirchhoff-Love shell element implemented into the isogeometric analysis framework. Defining a smoothing parametric surface via 2D bicubic spline fitting in the spatial, and by harmonic regression in the temporal domain, we are able to adequately mitigate the measurement inaccuracy. The ill-posedness of the problem requires certain assumptions on the displacement. In our case, based on numerical fluid structure interaction simulation observations, we hypothesized the incremental displacement vector of the reference surface to coincide with its corrected normal; hence the periodic movement was assured. Finally, we present two examples: an AAA and an undilated calcificated aorta. Strains in the diseased part were compared to those in a healthy arterial section of the same patient and found to have significant differences in both specimens. In the case of AAAs, high spatial gradients surrounding the dilated part indicate abrupt changes in material properties, a phenomenon less significant for the atherosclerotic case.

An Artificial Neural Network Stratifies the Risks of Reintervention and Mortality after Endovascular Aneurysm Repair; a Retrospective Observational study

Background

Lifelong surveillance after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA) is considered mandatory to detect potentially life-threatening endograft complications. A minority of patients require reintervention but cannot be predictively identified by existing methods. This study aimed to improve the prediction of endograft complications and mortality, through the application of machine-learning techniques.

Methods

Patients undergoing EVAR at 2 centres were studied from 2004-2010. Pre-operative aneurysm morphology was quantified and endograft complications were recorded up to 5 years following surgery. An artificial neural networks (ANN) approach was used to predict whether patients would be at low- or high-risk of endograft complications (aortic/limb) or mortality. Centre 1 data were used for training and centre 2 data for validation. ANN performance was assessed by Kaplan-Meier analysis to compare the incidence of aortic complications, limb complications, and mortality; in patients predicted to be low-risk, versus those predicted to be high-risk.

Results

761 patients aged 75 +/- 7 years underwent EVAR. Mean follow-up was 36+/- 20 months. An ANN was created from morphological features including angulation/length/areas/diameters/volume/tortuosity of the aneurysm neck/sac/iliac segments. ANN models predicted endograft complications and mortality with excellent discrimination between a low-risk and high-risk group. In external validation, the 5-year rates of freedom from aortic complications, limb complications and mortality were 95.9% vs 67.9%; 99.3% vs 92.0%; and 87.9% vs 79.3% respectively (p<0.001)

Conclusion

This study presents ANN models that stratify the 5-year risk of endograft complications or mortality using routinely available pre-operative data.

Risk of bias and magnitude of effect in orthodontic randomized controlled trials: a meta-epidemiological review

AIM

To assess the risk of bias (RoB) in a subset of randomized controlled trials (RCTs) published in orthodontic journals using the Cochrane RoB tool and to identify associations between domain RoB assessment and treatment effect estimates.

MATERIALS AND METHODS

Fifty consecutive issues of four major orthodontic journals were electronically searched to identify RCTs. The quality of the included studies was assessed using the Cochrane RoB tool, which involves seven domains rated as 'low', 'unclear' or 'high': random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, and selective outcome reporting, and other threats to internal validity. Estimates and confidence intervals (CIs) were recorded or calculated where possible for binary and continuous outcome measures. Meta-regression models were employed to assess the impact of RoB per domain on the magnitude of treatment effect.

RESULTS

One hundred and one eligible studies involving 128 pair-wise comparisons were retrieved. Blinding of outcome assessors and incomplete outcome data were frequently judged as 'high' for RoB both for studies with binary and continuous outcome (42.9 and 48.8 per cent, respectively). For binary outcomes, high RoB regarding random sequence generation [odds ratio (OR): 5.97, 95% CI: 2.03, 17.63, P-value: 0.002] and incomplete outcome data (OR: 4.07, 95% CI: 1.03, 16.15, P-value: 0.05) were more likely to provide exaggerated effect estimates.

CONCLUSIONS

There is a need for improved clinical trial methodology and reporting, in order to avoid inflated associations and erroneous conclusions.

Age-specific incidence, risk factors and outcome of acute abdominal aortic aneurysms in a defined population

BACKGROUND

Contemporary population-based data on age-specific incidence and outcome from acute abdominal aortic aneurysm (AAA) events are needed to understand the impact of risk factor modification and demographic change, and to inform AAA screening policy.

METHODS

In a prospective population-based study (Oxfordshire, UK, 2002-2014), event rates, incidence, early case fatality and long-term outcome from all acute AAA events were determined, both overall and in relation to the four main risk factors: smoking, hypertension, male sex and age.

RESULTS

Over the 12-year interval, 103 incident acute AAA events occurred in the study population of 92,728 (men 72·8 per cent; 59·2 per cent 30-day case fatality rate). The incidence per 100,000 population per year was 55 in men aged 65-74 years, but increased to 112 at age 75-84 years and to 298 at age 85 years or above. Some 66·0 per cent of all events occurred in those aged 75 years or more. The incidence at 65-74 years was highest in male smokers (274 per 100,000 population per year); 27 (96 per cent) of 28 events in men aged less than 75 years occurred in ever-smokers. Mean(s.d.) age at event was lowest in current smokers (72·2(7·2) years), compared with that in ex-smokers (81·2(7·0) years) and never-smokers (83·3(7·9) years) (P < 0·001). Hypertension was the predominant risk factor in women (diagnosed in 93 per cent), with 20 (71 per cent) of all 28 events in women occurring in those aged 75 years or above with hypertension. The 30-day case fatality rate increased from 40 per cent at age below 75 years to 69 per cent at age 75 years or more (P = 0·008).

CONCLUSION

Two-thirds of acute AAA events occurred at age 75 years or above, and more than 25 per cent of events were in women. Taken with the strong associations with smoking and hypertension, these findings could have implications for AAA screening.

Systematic Review and Meta-analysis of Long-term survival After Elective Infrarenal Abdominal Aortic Aneurysm Repair 1969-2011: 5 Year Survival Remains Poor Despite Advances in Medical Care and Treatment Strategies

Background

Improved critical care, pre-operative optimization, and the advent of endovascular surgery (EVAR) have improved 30 day mortality for elective abdominal aortic aneurysm (AAA) repair. It remains unknown whether this has translated into improvements in long-term survival, particularly because these factors have also encouraged the treatment of older patients with greater comorbidity. The aim of this study was to quantify how 5 year survival after elective AAA repair has changed over time.

Methods

A systematic review was performed identifying studies reporting 5 year survival after elective infrarenal AAA repair. An electronic search of the Embase and Medline databases was conducted to January 2014. Thirty-six studies, 60 study arms, and 107,814 patients were identified. Meta-analyses were conducted to determine 5 year survival and to report whether 5 year survival changed over time.

Results

Five-year survival was 69% (95% CI 67 to 71%, I² = 87%). Meta-regression on study midpoint showed no improvement in 5 year survival over the period 1969–2011 (log OR −0.001, 95% CI −0.014–0.012). Larger average aneurysm diameter was associated with poorer 5 year survival (adjusted log OR −0.058, 95% CI −0.095 to −0.021, I² = 85%). Older average patient age at surgery was associated with poorer 5 year survival (adjusted log OR −0.118, 95% CI −0.142 to −0.094, I² = 70%). After adjusting for average patient age, an improvement in 5 year survival over the period that these data spanned was obtained (adjusted log OR 0.027, 95% CI 0.012 to 0.042).

Conclusion

Five-year survival remains poor after elective AAA repair despite advances in short-term outcomes and is associated with AAA diameter and patient age at the time of surgery. Age-adjusted survival appears to have improved; however, this cohort as a whole continues to have poor long-term survival. Research in this field should attempt to improve the life expectancy of patients with repaired AAA and to optimise patient selection.

Late mortality in females after endovascular aneurysm repair

BACKGROUND

Abdominal aortic aneurysm (AAA) rupture is an adverse arterial remodeling event with high mortality risk. Because females have increased rupture risk with smaller AAAs (<5.5 cm), many recommend elective repair before the AAA reaches 5.5 cm. Elective repair improves survival for large AAAs, but long-term benefits of endovascular aneurysm repair (EVAR) for small AAAs in females remain less understood. The objective of this study was to identify if differences in late mortality exist between females undergoing elective EVAR at our institution for small and/or slow-growing AAAs compared with those who meet standard criteria.

METHODS

We retrospectively analyzed all patients that underwent EVAR for infrarenal AAA from June, 2009-June, 2013. We excluded patients that were male, treated emergently or for iliac artery aneurysm, and that received renal and/or mesenteric artery stenting. Patients did not meet anatomic criteria if preoperative AAA diameter was <5.5 cm or enlarged <0.5 cm over 6 mo. Late mortality was assessed from the social security death index.

RESULTS

Thirty-six of 162 elective EVAR patients (22.2%) were female (mean follow-up, 37.2 mo). Twenty patients (55.6%) met AAA size and/or growth criteria, whereas 16 (44.4%) did not meet criteria. Despite comparable demographics, comorbidities, and complications, patients that did not meet criteria had higher late mortality (37.5% versus 5%; P = 0.03) with a trend toward increased reoperation rate (25% versus. 5%; P = 0.48). Meeting size and/or growth criteria decreased odds of late death (odds ratio, 0.09; 95% confidence intervals, 0.01-0.83).

CONCLUSIONS

There is increased late mortality in females receiving elective EVAR at our institution for small and/or slow-growing AAAs. This late mortality may limit the benefits of EVAR for this population.

Endovascular strategy or open repair for ruptured abdominal aortic aneurysm: one-year outcomes from the IMPROVE randomized trial

Aims

To report the longer term outcomes following either a strategy of endovascular repair first or open repair of ruptured abdominal aortic aneurysm, which are necessary for both patient and clinical decision-making.

Methods and results

This pragmatic multicentre (29 UK and 1 Canada) trial randomized 613 patients with a clinical diagnosis of ruptured aneurysm; 316 to an endovascular first strategy (if aortic morphology is suitable, open repair if not) and 297 to open repair. The principal 1-year outcome was mortality; secondary outcomes were re-interventions, hospital discharge, health-related quality-of-life (QoL) (EQ-5D), costs, Quality-Adjusted-Life-Years (QALYs), and cost-effectiveness [incremental net benefit (INB)]. At 1 year, all-cause mortality was 41.1% for the endovascular strategy group and 45.1% for the open repair group, odds ratio 0.85 [95% confidence interval (CI) 0.62, 1.17], P = 0.325, with similar re-intervention rates in each group. The endovascular strategy group and open repair groups had average total hospital stays of 17 and 26 days, respectively, P < 0.001. Patients surviving rupture had higher average EQ-5D utility scores in the endovascular strategy vs. open repair groups, mean differences 0.087 (95% CI 0.017, 0.158), 0.068 (95% CI −0.004, 0.140) at 3 and 12 months, respectively. There were indications that QALYs were higher and costs lower for the endovascular first strategy, combining to give an INB of £3877 (95% CI £253, £7408) or €4356 (95% CI €284, €8323).

Conclusion

An endovascular first strategy for management of ruptured aneurysms does not offer a survival benefit over 1 year but offers patients faster discharge with better QoL and is cost-effective.

Clinical trial registration

ISRCTN 48334791.

Late open conversion after endovascular abdominal aortic aneurysm repair

OBJECTIVE

This study determined the incidence, the surgical details, and the outcome of late open conversion after failed endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm.

METHODS

A review of English-language medical literature from 1991 to 2014 was conducted using the PubMed and EMBASE databases to find all studies involving late conversion after EVAR for abdominal aortic aneurysm. The search identified 26 articles encompassing 641 patients (84% men; median age, 73.5 years).

RESULTS

Mean interval from the initial implantation was 38.5 ± 10.7 months. The cumulative single-center open conversion rate was 3.7%. The indications for late open conversion included endoleak in 62.4%, infection in 9.5%, migration in 5.5%, and thrombosis in 6.7%. Operations were urgent in 22.5% of the patients. The 30-day mortality was 9.1%. Mortality rates were different between elective (3.2%) and nonelective patients (29.2%). Five aneurysm-related deaths (1.5%) and two graft infections (0.6%) occurred during a median follow-up of 26.4 months (range, 5-50.2 months).

CONCLUSIONS

The number of patients with failed EVAR and without further options for endovascular salvage is growing. Endoleak remains the most important weakness of EVAR as the leading cause of late open conversion. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. Open repair still represents a valuable solution for many patients with failed EVAR.

International validation of a risk score for complications and reinterventions after endovascular aneurysm repair

Background

Lifelong surveillance is considered mandatory after endovascular repair (EVAR) of abdominal aortic aneurysms to detect endograft complications and prevent aneurysm rupture. Current protocols are not cost-effective or clinically effective. The international validity of the St George's Vascular Institute (SGVI) score for EVAR complications was examined.

Methods

The ENGAGE registry recruited patients undergoing EVAR at 79 centres in 30 countries. Reinterventions and endograft complications were recorded for up to 3 years after surgery. Preoperative aneurysm morphology was extracted from the registry database, and used to predict whether patients would be at low or high risk of complications after EVAR based on the SGVI score. Kaplan–Meier analysis was used to compare the incidence of endograft complications and reinterventions in patients predicted to be at low risk compared with those predicted to be at high risk.

Results

Some 1207 patients underwent EVAR, with follow-up of up to 3 years. The SGVI score accurately discriminated freedom from reinterventions (90·5 versus 79·3 per cent in low- versus high-risk patients; P &lt; 0·001), freedom from endograft complications (77·9 versus 69·6 per cent in low- versus high-risk patients; P = 0·012), and freedom from a composite outcome measure of reinterventions or endograft complications (75·0 versus 66·1 per cent in low- versus high-risk patients; P = 0·006) during mid-term follow-up.

Conclusion

This study has provided international validation of a morphological risk score that predicts mid-term reinterventions and endograft complications. The results may enable risk-stratified surveillance after EVAR.

Adapting health promotion interventions for ethnic minority groups: a qualitative study

Adaptation of health interventions has garnered international support across academic disciplines and among various health organizations. Through semi-structured interviews, we sought to explore and understand the perspectives of 26 health researchers and promoters located in the USA, UK, Australia, New Zealand and Norway, working with ethnic minority populations, specifically African-, South Asian- and Chinese-origin populations in the areas of smoking cessation, increasing physical activity and healthy eating, to better understand how adaptation works in practice. We drew on the concepts of intersectionality, representation and context from feminist, sociology and human geography literature, respectively, to help us understand how adaptations for ethnic groups approach the variable of ethnicity. Findings include (i) the intersections of ethnicity and demographic variables such as age and gender highlight the different ways in which people interact, interpret and participate in adapted interventions; (ii) the representational elements of ethnicity such as ancestry or religion are more complexly lived than they are defined in adapted interventions and (iii) the contextual experiences surrounding ethnicity considerations shape the receptivity, durability and continuity of adapted interventions. In conclusion, leveraging the experience and expertise of health researchers and promoters in light of three social science concepts has deepened our understanding of how adaptation works in principle and in practice for ethnic minority populations.

Results of the endovascular abdominal aortic aneurysm repair using the Anaconda aortic endograft

OBJECTIVE

The objective of this study was to evaluate early and late results of the Anaconda aortic endograft (Vascutek, Terumo, Inchinnan, Scotland) in a single-center experience.

METHODS

From September 2005 to March 2012, patients underwent endovascular aortic repair for abdominal aortic aneurysm (AAA) with Anaconda endograft were prospectively enrolled in a dedicated database. Demographic and aortoiliac morphological data were considered. Preoperative planning was based on thoracoabdominal and pelvic computed tomography angiography. Follow-up included duplex ultrasound or computed tomography angiography at 1, 6, and 12 months and yearly thereafter. Primary end points were technical success, early and late primary and primary assisted clinical success (CS), overall and AAA-related survival and freedom from reinterventions. Secondary end points were endoleaks (ELs), steno-obstructive iliac leg complications, and AAA shrinkage.

RESULTS

An Anaconda endograft was implanted in 177 patients (male 94%; mean age, 73.3 ± 7.4 years; American Society of Anesthesiologists class III-IV, 85% and 9%, respectively). The mean AAA diameter, neck length, and diameter were 55 ± 9.7 mm, 26.7 ± 10 mm, and 23 ± 2.3 mm, respectively. There was an aortic neck angle >60° in 44 (25%) patients. Iliac angles >90° were observed in 152 (43%) iliac axes. Technical success was 98.9%. Early CS was 96%. Mean follow-up was 33 ± 23.3 months. Late assisted CS was 97.7%. Survival at 12, 24, and 36 months was 96.4%, 89%, and 86.2%, respectively. There was only one case of late AAA-related mortality. Freedom from reintervention was 94%, 92%, and 85% at 12, 24, and 36 months, respectively. Three (1.7%) conversions occurred during follow-up. There were 14.1% ELs at the completion angiography (EL Ia, 1.1%; EL II, 13%). Late ELs were 20.2% (EL Ia, 1.1%; EL Ib, 2.2%; EL II, 16.9%). Iliac leg complications occurred in 5.6% of the cases. An AAA shrinkage >5 mm was observed in 130 (73.4%) patients. In 7 (4%) cases there was an AAA enlargement >5 mm.

CONCLUSIONS

Data in our series demonstrate that the Anaconda endograft has good early and late results in the treatment of AAAs.

Stent graft infection secondary to appendicitis: an unusual complication of endovascular abdominal aortic aneurysm repair

We present a case of a 73-year-old gentleman with an aortic endograft infection post endovascular abdominal aneurysm repair (EVAR), from whence erosion has come in from an acutely inflamed appendix. To our best understanding, there is no similar case published in the literature. Intra-operatively, there was obvious inflammation and oedema over the retroperitoneal tissue, with frank pus and thrombotic material projecting from the aorta. The tip of an obviously inflamed appendix had stuck to and eroded through the aortic sac, seeding the infection. The endograft was explanted and the aneurysm sac oversewn. Lower limb circulation was preserved with a right axillo-femoral Dacron bypass graft. This case highlights a rare complication following EVAR, and for one to consider unusual sources of graft infection.

Elective endovascular aortic repair conversion for type Ia endoleak is not associated with increased morbidity or mortality compared with primary juxtarenal aneurysm repair

OBJECTIVE

Type Ia endoleak after endovascular aortic repair (EVAR) can be a challenging complication to manage, and due to concerns regarding morbidity and mortality of open surgical conversion (OSC), reports of complex endoluminal salvage techniques are increasing. Despite development of these endovascular remedial strategies, many patients ultimately require OSC. The purpose of this analysis was to outcomes of elective OSC for type Ia endoleak and compare them with elective primary open juxtarenal aneurysm repair (OJAR) to determine if these concerns are warranted.

METHODS

From 2000 to 2012, 54 patients underwent EVAR OSC at median time of 27 months (interquartile range, 9-55 months). Indications included endograft thrombosis in 2 (4%), intraoperative EVAR failure in 3 (6%), rupture in 5 (9%), graft infection in 6 (11%), and type Ia endoleak in 25 (all: 38 [70%]). Because many OSCs are performed for emergency indications without endovascular options, we chose elective type Ia endoleak patients as our study group. These 25 patients were compared with an elective OJAR cohort matched by anatomy and comorbidities. Primary end points were 30-day and 1-year mortality. Secondary end points included early complications, cross-clamp time, procedure time, blood loss, and length of stay.

RESULTS

Demographic and comorbidity data in the OSC and OJAR groups did not differ, with the exception that OJAR patients presented with smaller aneurysm diameter and a higher rate of chronic obstructive pulmonary disease (P = .03). OSC patients more frequently underwent a nontube graft repair (OSC, n = 20 [80%] vs OJAR, n = 6 [24%]; P = .0002), required longer procedure times (P = .03), and received more plasma transfusions (P = .03). The 30-day mortality was 4% in both groups (observed difference in rates, 0%; 95% confidence interval for difference in mortality rates, -14.0% to 14.0%; P = 1). A similar rate of major complications occurred (OSC, n = 9 [36%] vs OJAR, n = 8 [32%]; P = 1). One-year survival was 83% in OSC and 91% in OJAR (observed difference, 7%; 95% confidence interval, -15% to 29%; P = .65).

CONCLUSIONS

Despite many advances in EVAR technology, the need for OSC persists and will likely become more common as older-generation devices fail or providers attempt EVAR in more anatomically complex patients. Elective OSC for type Ia endoleak can be technically challenging but is not associated with increased morbidity or mortality compared with OJAR in appropriately selected patients. These results should be considered before pursuing complex endovascular remediation of EVAR failures.

Endovascular treatment for ruptured abdominal aortic aneurysm

BACKGROUND

An abdominal aortic aneurysm (AAA) (pathological enlargement of the aorta) can develop in both men and women as they grow older. It is most commonly seen in men over the age of 65 years. Progressive aneurysm enlargement can lead to rupture and massive internal bleeding, a fatal event unless timely repair can be achieved. Despite improvements in perioperative care, mortality remains high (approximately 50%) after conventional open surgical repair. A newer minimally invasive technique, endovascular aneurysm repair (EVAR), has been shown to reduce early morbidity and mortality as compared to conventional open surgery for planned AAA repair. Emergency endovascular aneurysm repair (eEVAR) has been used successfully to treat ruptured abdominal aortic aneurysm (RAAA), proving that it is feasible in selected patients. However, it is not yet known if eEVAR will lead to significant improvements in outcomes for these patients or indeed if it can replace conventional open repair as the preferred treatment for this lethal condition.

OBJECTIVES

To assess the advantages and disadvantages of emergency endovascular aneurysm repair (eEVAR) in comparison with conventional open surgical repair for the treatment of ruptured abdominal aortic aneurysm (RAAA). This will be determined by the effect on short-term mortality, major complication rates, aneurysm exclusion, and late complications when compared with the effects in patients who have had conventional open repair of RAAA.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 2). Reference lists of relevant publications were also checked.

SELECTION CRITERIA

Randomised controlled trials in which patients with a clinically or radiologically diagnosed RAAA were randomly allocated to eEVAR or conventional open surgical repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by at least two review authors. Data extraction and quality assessment were also completed independently by two review authors. Disagreements were resolved through discussion. Meta-analysis was performed using fixed-effect models with odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous data and mean differences with 95% CIs for continuous data.

MAIN RESULTS

Three randomised controlled trials were included in this review. A total of 761 patients with a clinical or radiological diagnosis of RAAA were randomised to receive either eEVAR or open surgical repair. Overall risk of bias was low but one study did not adequately report random sequence generation, putting it at risk of selection bias, two studies did not report on outcomes identified in their protocol, indicating reporting bias, and one study was underpowered. There was no clear evidence to support a difference between the two interventions on 30-day (or in-hospital) mortality, OR of 0.91 (95% CI 0.67 to 1.22; P = 0.52). The 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, re-operation, amputation, and respiratory failure. Individual complication outcomes were reported in only one or two studies and therefore no robust conclusion can currently be drawn. For complication outcomes that did include at least two studies in the meta-analysis there was no clear evidence to support a difference between eEVAR and open repair. Six-month outcomes were evaluated in only a single study, which included mortality and re-operation, with no clear evidence of a difference between the interventions and no overall association. Cost per patient was only evaluated in a single study and therefore no overall associations can currently be derived.

AUTHORS' CONCLUSIONS

The conclusions of this review are currently limited by the paucity of data. From the data available there is no difference in the outcomes evaluated in this review between eEVAR and open repair, specifically 30-day mortality. Not enough information was provided for complications in order to make a well informed conclusion at this time. Long-term data are lacking for both survival and late complications. More high quality, randomised controlled trials comparing eEVAR and open repair for the treatment of RAAA are needed in order to better understand if one method is superior to the other, or if there is no difference between the methods on relevant outcomes.

Challenges in modelling the cost effectiveness of various interventions for cardiovascular disease

OBJECTIVES

Decision analytic modelling is essential in performing cost-effectiveness analyses (CEAs) of interventions in cardiovascular disease (CVD). However, modelling inherently poses challenges that need to be dealt with since models always represent a simplification of reality. The aim of this study was to identify and explore the challenges in modelling CVD interventions.

METHODS

A document analysis was performed of 40 model-based CEAs of CVD interventions published in high-impact journals. We analysed the systematically selected papers to identify challenges per type of intervention (test, non-drug, drug, disease management programme, and public health intervention), and a questionnaire was sent to the corresponding authors to obtain a more thorough overview. Ideas for possible solutions for the challenges were based on the papers, responses, modelling guidelines, and other sources.

RESULTS

The systematic literature search identified 1,720 potentially relevant articles. Forty authors were identified after screening the most recent 294 papers. Besides the challenge of lack of data, the challenges encountered in the review suggest that it was difficult to obtain a sufficiently valid and accurate cost-effectiveness estimate, mainly due to lack of data or extrapolating from intermediate outcomes. Despite the low response rate of the questionnaire, it confirmed our results.

CONCLUSIONS

This combination of a review and a survey showed examples of CVD modelling challenges found in studies published in high-impact journals. Modelling guidelines do not provide sufficient guidance in resolving all challenges. Some of the reported challenges are specific to the type of intervention and disease, while some are independent of intervention and disease.

Endovascular Treatment versus Open Repair for Abdominal Aortic Aneurysms: The Influence of Fitness in Decision Making

Two methods of repair are currently available for an abdominal aortic aneurysm (AAA), open aneurysm repair and endovascular aneurysm repair (EVAR). The decision making depends on the balance of risks and benefits. The treating physician must take into account the patient's life expectancy, the patient's fitness, the anatomic suitability that makes endovascular repair possible, and finally the patient's preference. The patient's fitness is an important variable predicting the outcome of AAA surgical reconstruction. The hypothesis is that the impact of risk factors upon perioperative mortality might differ between patients undergoing open repair and endovascular repair. The purpose of this review article is to investigate whether fitter patients with a large AAA benefit more from having endovascular rather than open repair. According to the available data, there is emerging evidence that patients at high medical risk for open repair may benefit from EVAR while in low risk patients with suitable anatomy for EVAR, both techniques have similar effects. There is rising evidence that a patient with ruptured AAA would benefit more from an endovascular procedure if eligible, and thus fitness in such emergencies is not the first priority but anatomical suitability for EVAR.

Clinical outcome of an extended proximal seal zone with the AFX endovascular aortic aneurysm system

OBJECTIVE

Despite improvements in endograft technology, operator skill, and patient selection, endovascular aneurysm repair continues to be associated with device-related complications. A retrospective, observational study was undertaken to evaluate the clinical outcome and imaging findings of a unique device having externally-mounted, conformable graft material.

METHODS

Infrarenal abdominal aortic aneurysms were treated with the Endologix, Inc AFX endovascular aortic aneurysm system (Irvine, Calif) endograft in 108 consecutive patients over a 25-month period at two U.S. clinical sites. Baseline characteristics and procedural outcomes were reviewed by independent monitors. Serial computed tomography (CT) imaging assessments were performed by an independent core laboratory. Aortic neck characteristics and graft apposition were analyzed from center line-reformatted CT data sets in 37 patients in an imaging cohort comprising subjects with high-resolution baseline and follow-up CT imaging for precise assessment of aortic neck characteristics. The mean follow-up was 11 ± 5 months overall, 9 ± 6 months in patients with core laboratory imaging, and 5 ± 2 months for patients in the imaging cohort.

RESULTS

Among the 108 patients, 103 (95%) had intact aneurysms and five (4.6%) were treated for rupture; 80 (74%) were male and 28 (26%) were female. On average, 2.3 ± 0.7 endograft components were implanted per patient and no adjunctive proximal neck bare stents were used. There were no perioperative deaths in patients with intact aneurysms; two patients who presented with ruptured aortic aneurysms (40%) died. Major adverse events occurred within 30 days of implantation in two patients (1.9%) with intact aneurysms. Type II endoleaks were evident on completion angiography in 18 patients (16.7%). Core laboratory analysis of CT studies identified two patients with type Ia endoleaks (2.3%), two with type III endoleaks (2.3%), and five with type II endoleaks (5.7%). Aneurysm-related secondary procedures were required in five patients over the first year of follow-up (4.6%). No patient developed endograft limb occlusion or aneurysm rupture and there were no open surgical conversions. In the imaging cohort, 360° graft-to-aortic wall apposition was continuous over a length of 25 ± 17 mm and extended the seal zone an average of 5 mm beyond the end of the anatomic neck. Early sac regression was correlated with neck length (P = .019) and graft-to-aortic apposition surface area (P = .039).

CONCLUSIONS

The real-world use of the AFX endograft was associated with a low rate of device-and procedure-related complications. The ability to achieve an extended seal zone beyond the anatomical neck might in part contribute to positive outcomes, including the low type Ia and type II endoleak rate. These findings suggest that the AFX device might offer some advantages over other currently marketed endografts, but confirmation awaits the availability of longer-term outcome data.

Cost-effectiveness of the National Health Service Abdominal Aortic Aneurysm Screening Programme in England

BACKGROUND

Implementation of the National Health Service abdominal aortic aneurysm (AAA) screening programme (NAAASP) for men aged 65 years began in England in 2009. An important element of the evidence base supporting its introduction was the economic modelling of the long-term cost-effectiveness of screening, which was based mainly on 4-year follow-up data from the Multicentre Aneurysm Screening Study (MASS) randomized trial. Concern has been expressed about whether this conclusion of cost-effectiveness still holds, given the early performance parameters, particularly the lower prevalence of AAA observed in NAAASP.

METHODS

The existing published model was adjusted and updated to reflect the current best evidence. It was recalibrated to mirror the 10-year follow-up data from MASS; the main cost parameters were re-estimated to reflect current practice; and more robust estimates of AAA growth and rupture rates from recent meta-analyses were incorporated, as were key parameters as observed in NAAASP (attendance rates, AAA prevalence and size distributions).

RESULTS

The revised and updated model produced estimates of the long-term incremental cost-effectiveness of £5758 (95 per cent confidence interval £4285 to £7410) per life-year gained, or £7370 (£5467 to £9443) per quality-adjusted life-year (QALY) gained.

CONCLUSION

Although the updated parameters, particularly the increased costs and lower AAA prevalence, have increased the cost per QALY, the latest modelling provides evidence that AAA screening as now being implemented in England is still highly cost-effective.

Improved results in the management of ruptured abdominal aortic aneurysm may not be on the basis of endovascular aneurysm repair alone

Recent improvement in the survival of patients presenting with a ruptured abdominal aortic aneurysm (rAAA) has been credited to endovascular aneurysm repair (EVAR). We present our clinical series in the management of rAAA from 2007 to 2011. A total of 55 consecutive patient charts were reviewed. Thirty-eight patients underwent EVAR, 17 of the 55 patients did not have favorable anatomy for EVAR. Nine of the 17 patients underwent standard open repair. Eight patients underwent a 'hybrid repair' defined as suprarenal aortic endovascular balloon control followed by open repair. Overall 30-day mortality for all 55 patients was 22%. Mortality for the patients managed by endovascular aortic aneurysm repair was 26% compared with 22% with open repair. There were no deaths in the eight patients undergoing the hybrid repair. Endovascular balloon control of the aorta followed by open rAAA repair in patients who are not candidates for rEVAR has produced good results in our experience. Improved results being reported in the management of rAAA may not be on the basis of endovascular repair alone.

Update on abdominal aortic aneurysm research: from clinical to genetic studies

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta with a diameter of at least 3.0 cm. AAAs are often asymptomatic and are discovered as incidental findings in imaging studies or when the AAA ruptures leading to a medical emergency. AAAs are more common in males than females, in individuals of European ancestry, and in those over 65 years of age. Smoking is the most important environmental risk factor. In addition, a positive family history of AAA increases the person's risk for AAA. Interestingly, diabetes has been shown to be a protective factor for AAA in many large studies. Hallmarks of AAA pathogenesis include inflammation, vascular smooth muscle cell apoptosis, extracellular matrix degradation, and oxidative stress. Autoimmunity may also play a role in AAA development and progression. In this Outlook paper, we summarize our recent studies on AAA including clinical studies related to surgical repair of AAA and genetic risk factor and large-scale gene expression studies. We conclude with a discussion on our research projects using large data sets available through electronic medical records and biobanks.

Long-term cost-effectiveness analysis of endovascular versus open repair for abdominal aortic aneurysm based on four randomized clinical trials

Background

A number of published economic evaluations of elective endovascular aneurysm repair (EVAR) versus open repair for abdominal aortic aneurysm (AAA) have come to differing conclusions about whether EVAR is cost-effective. This paper reviews the current evidence base and presents up-to-date cost-effectiveness analyses in the light of results of four randomized clinical trials: EVAR-1, DREAM, OVER and ACE.

Methods

Markov models were used to estimate lifetime costs from a UK perspective and quality-adjusted life-years (QALYs) based on the results of each of the four trials. The outcomes included in the model were: procedure costs, surveillance costs, reintervention costs, health-related quality of life, aneurysm-related mortality and other-cause mortality. Alternative scenarios about complications, reinterventions and deaths beyond the trial were explored.

Results

Models based on the results of the EVAR-1, DREAM or ACE trials did not find EVAR to be cost-effective at thresholds used in the UK (up to £30 000 per QALY). EVAR seemed cost-effective according to models based on the OVER trial. These results seemed robust to alternative model scenarios about events beyond the trial intervals.

Conclusion

These analyses did not find that EVAR is cost-effective compared with open repair in the long term in trials conducted in European centres. EVAR did appear to be cost-effective based on the OVER trial, conducted in the USA. Caution must be exercised when transferring the results of economic evaluations from one country to another.

Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm

BACKGROUND

Emergency endovascular repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA) may have lower operative mortality rates than open surgical repair. Concerns remain that the early survival benefit after EVAR for rAAA may be offset by late reinterventions. The aim of this study was to compare reintervention rates and cost-effectiveness of EVAR and open repair for rAAA.

METHODS

A retrospective analysis was undertaken of patients with rAAA undergoing EVAR or open repair over 6 years. A health economic model developed for the cost-effectiveness of elective EVAR was used in the emergency setting.

RESULTS

Sixty-two patients (mean age 77·9 years) underwent EVAR and 85 (mean age 75·9 years) had open repair of rAAA. Median follow-up was 42 and 39 months respectively. There was no significant difference in 30-day mortality rates after EVAR and open repair (18 and 26 per cent respectively; P = 0·243). Reintervention rates were also similar (32 and 31 per cent; P = 0·701). The mean cost per patient was €26,725 for EVAR and €30,297 for open repair, and the cost per life-year gained was €7906 and €9933 respectively (P = 0·561). Open repair had greater initial costs: longer procedural times (217 versus 178·5 min; P < 0·001) and intensive care stay (5·0 versus 1·0 days; P = 0·015). Conversely, EVAR had greater reintervention (€156,939 versus €35,335; P = 0·001) and surveillance (P < 0·001) costs.

CONCLUSION

There was no significant difference in reintervention rates after EVAR or open repair for rAAA. EVAR was as cost-effective at mid-term follow-up. The increased procedural costs of open repair are not outweighed by greater surveillance and reintervention costs after EVAR.

Endovascular treatment of abdominal aortic aneurysms

Patients with abdominal aortic aneurysms (AAAs) are usually treated with endovascular aneurysm repair (EVAR), which has become the standard of care in many hospitals for patients with suitable anatomy. Clinical evidence indicates that EVAR is associated with superior perioperative outcomes and similar long-term survival compared with open repair. Since the randomized, controlled trials that provided this evidence were conducted, however, the stent graft technology for infrarenal AAA has been further developed. Improvements include profile downsizing, optimization of sealing and fixation, and the use of low porosity fabrics. In addition, imaging techniques have improved, enabling better preoperative planning, stent graft placement, and postoperative surveillance. Also in the past few years, fenestrated and branched stent grafts have increasingly been used to manage anatomically challenging aneurysms, and experiments with off-label use of stent grafts have been performed to treat patients deemed unfit or unsuitable for other treatment strategies. Overall, the indications for endovascular management of AAA are expanding to include increasingly complex and anatomically challenging aneurysms. Ongoing studies and optimization of imaging, in addition to technological refinement of stent grafts, will hopefully continue to broaden the utilization of EVAR.