The Viborg Vascular (VIVA) screening trial of 65-74 year old men in the central region of Denmark: study protocol

Gender-specific Predicted Normal Aortic Size and Its Consequences of the Population-Based Prevalence of Abdominal Aortic Aneurysms

BACKGROUND

To investigate if a relative-size-index of the abdominal aortic diameter influences the prevalence estimates of abdominal aortic dilatations compared to absolute diameters.

METHODS

Cross-sectional study. Participants from the Viborg Vascular Screening Trial, Viborg Women Cohort, and the Viborg Screening Program. Through multivariate linear regression analyses, 2 gender-specific prediction-equations were developed based upon body-surface area and age. The definitions of absolute and relative size of aortic ectasies were 25-29 mm and 1.25-1.49× individual-predicted size (IPS), abdominal aortic aneurysm (AAA) 30 mm and 1.5× IPS, and large repair-recommendable AAA ≥55 mm or ≥ 2.75× IPS, respectively.

RESULTS

Nineteen thousand two hundred and sixty nine males (69.6 years) and 2,426 females (67.1 years) attended the population- and ultrasound-based screening studies for AAA. The mean peak systolic abdominal anterior-posterior inner to inner diameter was 19.1 mm (±5.3 mm) and 16.6 mm (±2.8 mm) (P < 0.001) in males and females, respectively. Body surface area showed the strongest correlation with aortic diameters in both males (r = 0.19, P < 0.001) and females (r = 0.17, P < 0.001). Age correlated significantly with size, but only in males (r = 0.03, P < 0.001). The prevalence in men of absolute size-defined and relative size index-defined screening-detected aortic ectasies, AAAs and repair-recommendable AAAs were: 5.9% and 9.5% (P < 0.001), 3.3% and 4.2% (P < 0.001) and 9.9% and 15.2% (P = 0.004), respectively. Prevalence in females of absolute-size-defined and relative-size-index-defined screening-detected aortic ectasies, AAAs and repair-recommendable AAAs were 1.2% and 5.8% (P < 0.001), 0.5% and 1.3% (P = 0.003) and 0.0% and 23.1% (P = 0.553), respectively.

CONCLUSIONS

Despite statistical differences, ultrasound-based absolute diameters to detect AAA seem acceptable in men. In females, poor agreements were noticed concerning all 3 categories of aneurysms, indicating that the current absolute diagnostic cut-points do not reflect female anatomy.

The association between diabetes and abdominal aortic aneurysms in men: results of two Danish screening studies, a systematic review, and a meta-analysis of population-based screening studies

BACKGROUND

A paradoxical protective effect of diabetes on the development and progression of abdominal aortic aneurysms (AAA) has been known for years. This study aimed to investigate whether the protective role of diabetes on AAAs has evolved over the years.

METHODS

A cross-sectional study, a systematic review and meta-analysis. This study was based on two large, population-based, randomised screening trials of men aged 65-74; VIVA (2008-2011) and DANCAVAS (2014-2018), including measurement of the abdominal aorta by ultrasound or CT, respectively. Analyses were performed using multiple logistic regressions to estimate the odds ratios (ORs) for AAAs in men with diabetes compared to those not having diabetes. Moreover, a systematic review and meta-analysis of population-based screening studies of AAAs to visualise a potential change of the association between diabetes and AAAs. Studies reporting only on women or Asian populations were excluded.

RESULTS

In VIVA, the prevalence of AAA was 3.3%, crude OR for AAA in men with diabetes 1.04 (95% confidence interval, CI, 0.80-1.34), and adjusted OR 0.64 (CI 0.48-0.84). In DANCAVAS, the prevalence of AAA was 4.2%, crude OR 1.44 (CI 1.11-1.87), and adjusted OR 0.78 (CI 0.59-1.04). Twenty-three studies were identified for the meta-analysis (N = 224 766). The overall crude OR was 0.90 (CI 0.77-1.05) before 2000 and 1.16 (CI 1.03-1.30) after 1999. The overall adjusted OR was 0.63 (CI 0.59-0.69) before 2000 and 0.69 (CI 0.57-0.84) after 1999.

CONCLUSION

Both the crude and adjusted OR showed a statistically non-significant trend towards an increased risk of AAA by the presence of diabetes. If this represents an actual trend, it could be due to a change in the diabetes population.

TRIAL REGISTRATION

DANCAVAS: Current Controlled Trials: ISRCTN12157806. VIVA: ClinicalTrials.gov NCT00662480.

Protocol for a cohort study to evaluate the effectiveness and cost-effectiveness of general population screening for cardiovascular disease: the Viborg Screening Programme (VISP)

INTRODUCTION

The prevalence of cardiovascular disease (CVD) is increasing. Furthermore, asymptomatic individuals may not receive timely preventive initiatives to minimise the risk of further CVD events. Paradoxically, 80% of CVD events are preventable by early detection, followed by prophylactic initiatives. Consequently, we introduced the population-based Viborg Screening Programme (VISP) for subclinical and manifest CVD, focusing on commonly occurring, mainly asymptomatic conditions, followed by prophylactic initiatives.The aim of the VISP was to evaluate the health benefits, harms and cost-effectiveness of the VISP from a healthcare sector perspective. Furthermore, we explored the participants' perspectives.

METHODS AND ANALYSIS

From August 2014 and currently ongoing, approximately 1100 men and women from the Viborg municipality, Denmark, are annually invited to screening for abdominal aortic aneurysm, peripheral arterial disease, carotid plaque, hypertension, diabetes mellitus and cardiac arrhythmia on their 67th birthday. A population from the surrounding municipalities without access to the VISP acts as a control. The VISP invitees and the controls are followed on the individual level by nationwide registries. The primary outcome is all-cause mortality, while costs, hospitalisations and deaths from CVD are the secondary endpoints.Interim evaluations of effectiveness and cost-effectiveness are planned every 5 years using propensity score matching followed by a Cox proportional hazards regression analysis by the 'intention-to-treat' principle. Furthermore, censoring-adjusted incremental costs, life-years and quality-adjusted life-years are estimated. Finally, the participants' perspectives are explored by semistructured face-to-face interviews, with participant selection representing participants with both negative and positive screening results.

ETHICS AND DISSEMINATION

The VISP is not an interventional trial. Therefore, approval from a regional scientific ethical committee is not needed. Data collection from national registries was approved by the Regional Data Protection Agency (record no. 1-16-02-232-15). We ensure patient and public involvement in evaluating the acceptability of VISP by adopting an interviewing approach in the study.

TRIAL REGISTRATION NUMBER

NCT03395509.

Malondialdehyde-modified HDL particles elicit a specific IgG response in abdominal aortic aneurysm

High Density Lipoprotein (HDL) plays a protective role in abdominal aortic aneurysm (AAA); however, recent findings suggest that oxidative modifications could lead to dysfunctional HDL in AAA. This study aimed at testing the effect of oxidized HDL on aortic lesions and humoral immune responses in a mouse model of AAA induced by elastase, and evaluating whether antibodies against modified HDL can be found in AAA patients. HDL particles were oxidized with malondialdehyde (HDL-MDA) and the changes were studied by biochemical and proteomics approaches. Experimental AAA was induced in mice by elastase perfusion and then mice were treated with HDL-MDA, HDL or vehicle for 14 days. Aortic lesions were studied by histomorphometric analysis. Levels of anti-HDL-MDA IgG antibodies were measured by an in-house immunoassay in the mouse model, in human tissue-supernatants and in plasma samples from the VIVA cohort. HDL oxidation with MDA was confirmed by enhanced susceptibility to diene formation. Proteomics demonstrated the presence of MDA adducts on Lysine residues of HDL proteins, mainly ApoA-I. MDA-modification of HDL abrogated the protective effect of HDL on cultured endothelial cells as well as on AAA dilation in mice. Exposure to HDL-MDA elicited an anti-HDL-MDA IgG response in mice. Anti-HDL-MDA were also detected in tissue-conditioned media from AAA patients, mainly in intraluminal thrombus. Higher plasma levels of anti-HDL-MDA IgG antibodies were found in AAA patients compared to controls. Anti-HDL-MDA levels were associated with smoking and were independent predictors of overall mortality in AAA patients. Overall, MDA-oxidized HDL trigger a specific humoral immune response in mice. Besides, antibodies against HDL-MDA can be detected in tissue and plasma of AAA patients, suggesting its potential use as surrogate stable biomarkers of oxidative stress in AAA.

Vitamin K2 Dependent Matrix Gla Protein Relating to Abdominal Aortic Aneurysm and Overall Mortality: A Combined Case Control and Cohort Study

OBJECTIVE

Inactivation of matrix Gla protein (MGP), using vitamin K antagonists or vitamin K deficiency results in increased vascular calcification, which has been associated with increased risk of symptomatic or ruptured abdominal aortic aneurysm (AAA). Insufficient activation of MGP leads to increased levels of undercarboxylated forms of MGP, measured as a dephosphorylated, undercarboxylated MGP (dp-ucMGP) in plasma. This study aimed to investigate whether the level of inactivated MGP influenced the risk of having an AAA, the risk of AAA progression, and overall mortality.

METHODS

This combined case control and cohort study was based on data from the randomised, clinically controlled Viborg Vascular (VIVA) screening trial. Cases (n = 487) with an AAA and controls (n = 189) with neither peripheral artery disease nor AAA, had their plasma quantified for dp-ucMGP. Plasma levels were compared with the presence of an AAA, AAA growth rate, need for repair, and overall mortality. dp-ucMGP was divided into tertiles in regression analyses.

RESULTS

The plasma levels of dp-ucMGP were higher for AAA cases compared with controls (median of 517 pmol/L vs. 495 pmol/L, p = .036). Adjusted analyses regarding dp-ucMGP being predictive of AAA, AAA growth rate, and need for repair all failed to show correlation. Overall mortality for AAA cases exhibited a significant association for the third tertile of dp-ucMGP with a hazard ratio of 2.55 (95% CI 1.29 - 5.05) compared with the first tertile. Overall mortality for controls was not correlated with dp-ucMGP plasma levels.

CONCLUSION

dp-ucMGP did not correlate with the risk of having an AAA, AAA growth rate, or risk of surgery. For people with an AAA, dp-ucMGP was correlated with an increased mortality risk for the highest tertile of dp-ucMGP. This could suggest a role for prophylactic measures with vitamin K2 supplements to people at risk of AAA.

Basement membrane collagen IV deficiency promotes abdominal aortic aneurysm formation

Abdominal aortic aneurysm (AAA) is a complex disease which is incompletely accounted for. Basement membrane (BM) Collagen IV (COL4A1/A2) is abundant in the artery wall, and several lines of evidence indicate a protective role of baseline COL4A1/A2 in AAA development. Using Col4a1/a2 hemizygous knockout mice (Col4a1/a2^+/-, 129Svj background) we show that partial Col4a1/a2 deficiency augmented AAA formation. Although unchallenged aortas were morphometrically and biomechanically unaffected by genotype, explorative proteomic analyses of aortas revealed a clear reduction in BM components and contractile vascular smooth muscle cell (VSMC) proteins, suggesting a central effect of the BM in maintaining VSMCs in the contractile phenotype. These findings were translated to human arteries by showing that COL4A1/A2 correlated to BM proteins and VSMC markers in non-lesioned internal mammary arteries obtained from coronary artery bypass procedures. Moreover, in human AAA tissue, MYH11 (VSMC marker) was depleted in areas of reduced COL4 as assessed by immunohistochemistry. Finally, circulating COL4A1 degradation fragments correlated with AAA progression in the largest Danish AAA cohort, suggesting COL4A1/A2 proteolysis to be an important feature of AAA formation. In sum, we identify COL4A1/A2 as a critical regulator of VSMC phenotype and a protective factor in AAA formation.

Clinical Benefit, Harm, and Cost Effectiveness of Screening Men for Peripheral Artery Disease: A Markov Model Based on the VIVA Trial

OBJECTIVE

Although screening for peripheral arterial disease (PAD) seems obvious due to its two to three times increased mortality, high prevalence in the elderly, ease of detection, and relatively harmless prevention, the evidence is sparse.

METHODS

A Markov decision model was created to model the lifetime effectiveness and cost effectiveness of general population PAD screening and relevant intervention in 65 year old men. The model was informed by original estimates from the VIVA trial data except for ankle brachial systolic blood pressure index test accuracy, quality of life, and background mortality, which were adopted from the literature. A Markov model was designed for 65 year old men, who were distributed in the starting states of no/detected/undetected PAD. The main outcomes were life years, quality adjusted life years, and costs of healthcare.

RESULTS

Screening for PAD reduced the rates of amputations and stroke by 10.9% and 2.4%, respectively, while it increased the rates of revascularisation, acute myocardial infarction, and major bleeding by 5.5%, 7.1%, and 4.3% respectively. The overall life expectancy was increased by 14 days per invited subject. The cost per life year/quality adjusted life year was estimated at €16 717/€20 673. On the addition of low dose rivaroxaban reduced the costs per life year gained by 40%. If the model ran for only five follow up years, screening reduced relative mortality by 1.71%, suggesting PAD screening accounts for one fourth of the reported overall 7% relative mortality risk reduction of combined abdominal aortic aneurysm, PAD, and hypertension screening.

CONCLUSION

Screening of men for PAD is likely to be both clinically effective and cost effective in a lifetime perspective.

Pharmacological Preventive Potential Among Attenders at Vascular Screening: Findings from the VIVA Trial

OBJECTIVE

Findings from the Viborg Vascular (VIVA) trial show a mortality benefit of multi-faceted vascular screening which was mainly ascribed to the initiation of prophylactic medication. However, the pharmacological preventive potential, which exists when individuals have a positive screening test result and do not already use statins and anti-platelet agents, has not been analysed. The aim of this study was to investigate factors associated with a pharmacological preventive potential of statins and anti-platelet agents among attenders vascular screening for abdominal aortic aneurysm (AAA) and peripheral arterial disease (PAD).

METHODS

This cross-sectional study used data from the VIVA trial screening arm including 25 074 men aged 64-75 years recruited between October 2008 and January 2011. Explanatory variables comprised socio-demographic- and socio-economic characteristics, comorbidities, medication use, and travel distance derived from nationwide registries. Outcomes included a positive screening test result, a pharmacological preventive potential, and attendance. Associations between the explanatory variables and the outcomes were investigated using the chi-square test and multivariate logistic regression.

RESULTS

The factors most likely to be associated with a pharmacological preventive potential for positive AAA screening comprised age >70 years (odds ratio (OR) 1.23, 95% confidence interval 1.00-1.51), existing chronic obstructive pulmonary disease (COPD) (OR 2.22, 95% CI 1.38-3.57), and use of anti-hypertensives (OR 1.37, 95% CI 1.09-1.71). For positive PAD screening age >70 years (OR 1.41, 95% CI 1.25-1.60), living alone (OR 1.34, 95% CI 1.14-1.56), low income, COPD (OR 2.13, 95% CI 159-283), use of anti-hypertensives (OR 1.14, 95% CI 1.00-1.29) or anti-diabetics (OR 1.12, 95% CI 1.01-1.28), and short travel distance were associated with a pharmacological preventive potential. For combined vascular screening, age >70 years, living alone, low income, COPD, and use of anti-hypertensives were associated with a pharmacological preventive potential. Among these subgroups, lower attendance was associated with age >70 years, living alone, low income, COPD, and use of anti-diabetics.

CONCLUSION

Future vascular screening programmes might benefit from tailoring information to subgroups who are more likely to benefit from screening but less likely to accept an offer.

IgG Anti-High Density Lipoprotein Antibodies Are Elevated in Abdominal Aortic Aneurysm and Associated with Lipid Profile and Clinical Features

High-density lipoproteins cholesterol (HDLc) levels are decreased in abdominal aortic aneurysm (AAA), which is hallmarked by autoimmunity and lipid aortic deposits. To investigate whether IgG anti-HDL antibodies were present in AAA and their potential association with clinical features, IgG anti-HDL and total IgG along with HDLc plasma levels were measured in 488 AAA patients and 184 controls from the Viborg Vascular (VIVA) study, and in tissue-conditioned media from AAA intraluminal thrombus and media layer samples compared to control aortas. Higher IgG anti-HDL levels were found in AAA compared to controls, even after correcting for total IgG, and after adjusting for potential confounders. IgG anti-HDL levels were correlated with aortic diameter in univariate and adjusted multivariate analyses. IgG anti-HDL antibodies were negatively associated with HDLc levels before and after correcting for potential confounders. Increased anti-HDL antibodies were identified in tissue-conditioned media from AAA samples compared to healthy aortas, with higher levels being observed in the media layer. In conclusion, increased IgG anti-HDL levels (both in plasma and in tissue) are linked to AAA, associated with aortic diameter and HDLc levels. These data suggest a potential immune response against HDL in AAA and support an emerging role of anti-HDL antibodies in AAA.

Plasma CCN2 is independently related to subsequent need for abdominal aorta aneurysm repair

The objective of this study was to determine if plasma CCN2 is associated with abdominal aorta aneurysm (AAA), and future need for AAA repair, and further to assess the potential clinical value of CCN2 in predicting disease outcome. CCN2 was quantified in plasma samples obtained from a cohort of 679 men aged 65-74 at initial ultrasound screening for AAA in the Viborg Vascular (VIVA) screening trial. Plasma CCN2 was correlated with need for future surgical repair in the whole study population (HR = 1.457 (1.081-1.962), p = .013) and in the AAA group alone (HR = 1.431 (1.064-1.926), p = .018), yet the predictive value (CCN2 > 0 and <0 of 0.52 and 0.55, respectively) disqualified its use in clinically relevant AAA repair prediction. In conclusion, CCN2 is independently related to subsequent need for AAA repair, but has negligible predictive power for clinical use.

Do Non-participants at Screening have a Different Threshold for an Acceptable Benefit-Harm Ratio than Participants? Results of a Discrete Choice Experiment

OBJECTIVE

The objective of the study was to investigate non-participants' preferences for cardiovascular disease screening programme characteristics and whether non-participation can be rationally explained by differences in preferences, decision-making styles and informational needs between non-participants and participants.

METHODS

We conducted a discrete choice experiment at three screening sites between June and December 2017 among 371 male non-participants and 830 male participants who were asked to trade different levels of five key programme characteristics (chance of health benefit, risk of overtreatment, risk of later regret, screening duration and screening location). Data were analysed using a multinomial mixed-logit model. Health benefit was used as a payment vehicle for estimation of marginal substitution rates.

RESULTS

Non-participants were willing to accept that 0.127 (95% confidence interval 0.103-0.154) fewer lives would be saved to avoid overtreatment of one individual, whilst participants were willing to accept 0.085 (95% confidence interval 0.077-0.094) fewer lives saved. This translates into non-participants valuing health benefits 7.9 times higher than overtreatment. The corresponding value of participants is 11.8. Similarly, non-participants had higher requirements than participants for advanced technology and a quicker screening duration. With regard to their participation decision, 64% of the non-participants felt certain about their choice compared with 89% among participants.

CONCLUSIONS

This study shows that non-participants have different preferences than participants at screening as they express relatively more concern about overtreatment and have higher requirements for a high-tech screening programme. Non-participants also report to be more uncertain about their participation decision and more often seek additional information to the standard information provided in the invitation letter. Further studies on informational needs and effective communication strategies are warranted to ensure that non-participation is a fully informed choice.

Critical appraisal of international guidelines for the screening and treatment of asymptomatic peripheral artery disease: a systematic review

Background

Peripheral artery disease (PAD) is often asymptomatic but increases the risk of developing cardiovascular events. Due to the uncertainties regarding the quality of related guidelines and a lack of clear-cut evidence, we performed a systematic review and critical appraisal of these guidelines to evaluate their consistency of the recommendations in asymptomatic PAD population.

Methods

Guidelines in English between January 1st, 2000 to December 31th, 2017 were screened in databases including Medline via PubMed, EMBASE, the G-I-N International Guideline Library, the National Guidelines Clearinghouse, the Canadian Medication Association Infobase and the National Library for Health. Those guidelines containing recommendations on screening and treatment for asymptomatic PAD were included, and three reviewers evaluated the quality of the guidelines using Appraisal of Guidelines Research and Evaluation (AGREE) II instrument. Related recommendations were then fully extracted and compared by two reviewers.

Results

Fourteen guidelines were included finally and the AGREE scores ranged from 39 to 73%. Most of included guidelines scored low in Rigor of development and Editorial independence, and only two guidelines (ACCF/AHA, AHA/ACC) reached the standard on Conflict of Interest from Institute of Medicine (IOM). Eight guidelines recommended screening at different strength while the others found insufficient evidence or were against screening. Conflicting recommendations on treatment were found in the target value of the lipid lowering and antiplatelet therapy. The treatment policies in three guidelines (BWG, CEVF, ESC) appeared more aggressive, but they had low transparency between guideline developer and industry or did not reach the standard of IOM.

Conclusions

Current guidelines on asymptomatic PAD varied in the methodological quality and fell short of the standard in the rigor of development and editorial independence. Conflicting recommendations were found both on the screening and treatment. More effort is needed to provide clear-cut evidences with high quality and transparency among guideline developer and industry.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0960-8) contains supplementary material, which is available to authorized users.

Plasma Cystatin B Association With Abdominal Aortic Aneurysms and Need for Later Surgical Repair: A Sub-study of the VIVA Trial

OBJECTIVE/BACKGROUND

The development of an abdominal aortic aneurysm (AAA) involves extensive extracellular matrix remodelling, leading to aortic wall weakening. This process is mediated by proteases, including cysteinyl cathepsins. Cystatins are their endogenous inhibitors. This study tested whether plasma cystatin B levels in patients with AAA differed from those of healthy controls.

METHODS

Plasma samples from patients with AAA and age matched controls were selected from the Viborg Vascular (VIVA) screening trial for AAA. Enzyme linked immunosorbent assay determined plasma cystatin B. T-test, logistic regression, Pearson's correlation and Cox regression tested whether plasma cystatin B correlates with AAA size and growth rate, or serves as a marker for AAA.

RESULTS

Plasma cystatin B levels were significantly higher in patients with AAA than in controls (p < 0.001). Logistic regression analysis showed that cystatin B tertile at baseline was associated with the presence of AAA before (odds ratio [OR] 1.656; p < 0.001) and after adjustment for peripheral arterial disease (PAD), chronic obstructive pulmonary disease (COPD), and previous ischaemic events (OR 1.526; p < 0.001). A t-test showed a significant association between cystatin B and PAD at screening, hospital diagnosis of COPD, previous atherosclerotic events, and use of low dose aspirin. Pearson's correlation test showed positive and significant associations between cystatin B and AAA size (r = 0.15; p < 0.001). Cox regression test showed that plasma cystatin B tertile at baseline was associated with later AAA surgical repair before (hazard ratio [HR] 1.387; p < 0.001) and after adjustment for PAD, COPD, previous ischaemic event, and maximum infrarenal aortic diameter (HR 1.523; p < 0.001).

CONCLUSION

In contrast to prior studies that showed that cystatin C is negatively associated with AAA development, this study demonstrated a positive association between cystatin B and AAA size and associations between cystatin B tertile at baseline and AAA presence and need for later surgical repair. It is possible that these two cystatins inhibit cathepsin activity and participate in AAA with different mechanisms.

Abdominal Aortic Aneurysms Growth Is Associated With High Concentrations of Plasma Proteins in the Intraluminal Thrombus and Diseased Arterial Tissue

Objective—

Porosity of the intraluminal thrombus (ILT) is believed to convey biologically active components from the bloodstream toward the aneurismal wall. Accumulation of molecules in the abdominal aortic aneurysmatic tissue may influence vascular protein turnover and regulate abdominal aortic aneurysm growth. We sought to identify proteins with concentrations in the ILT and the abdominal aortic aneurysm wall which associate with aneurysmal expansion rate.

Approach and Results—

Proteomic analysis by liquid chromatography tandem-mass spectrometry of separated wall and ILT samples was correlated with preoperative aneurysmal growth rate in 24 individuals operated electively for infrarenal abdominal aortic aneurysm. The median preoperative growth rate was 3.8 mm/y (interquartile range, 3) and the mean observational time was 3.3±1.7 years. Plasma components dominated the group of proteins with tissue concentrations, which correlate positively with growth rates ( P <0.001, Fisher exact test, both in the ILT and the wall). In contrast, in the wall and thrombus samples, ECM (extracellular matrix) proteins were significantly more prevalent in the group of proteins with negative correlations to growth rates ( P <0.05, Fisher exact test). Similarly, a long series of proteins, related to cellular functions correlated negatively to growth rates.

Conclusions—

When the preoperative aneurysmatic growth rate has been high, the concentration of many plasma proteins residing in the ILT and the aneurysmatic tissue is also high, compatible with the hypothesis of increased tissue porosity and accumulation of plasma components as a driver of aneurysm expansion. Moreover, many matrix and cellular proteins which are found in high concentrations in slower-growing aneurysms provides new knowledge about potential treatment targets.

Screening for Peripheral Artery Disease Using the Ankle-Brachial Index: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Peripheral artery disease (PAD) is associated with a high risk for cardiovascular events and poor ambulatory function, even in the absence of symptoms. Screening for PAD with the ankle-brachial index (ABI) may identify patients in need of treatment to improve health outcomes.

OBJECTIVE

To systematically review evidence for the US Preventive Services Task Force on PAD screening with the ABI, the diagnostic accuracy of the test, and the benefits and harms of treatment of screen-detected PAD.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant English-language studies published between January 2012 and May 2, 2017. Surveillance continued through February 7, 2018.

STUDY SELECTION

Studies of unselected or generally asymptomatic adults with no known cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Independent critical appraisal and data abstraction by 2 reviewers.

MAIN OUTCOMES AND MEASURES

Cardiovascular morbidity; PAD morbidity; mortality; health-related quality of life; diagnostic accuracy; and serious adverse events.

RESULTS

Five studies (N = 5864 participants) were included that examined the indirect evidence for the benefits and harms of screening and treatment of screen-detected PAD. No population-based screening trials evaluated the direct benefits or harms of PAD screening with the ABI alone. A single diagnostic accuracy study of the ABI compared with magnetic resonance angiography gold-standard imaging (n = 306) found low sensitivity (7%-34%) and high specificity (96%-100%) in a screening population. Two adequately powered trials (n = 4626) in asymptomatic populations with and without diabetes with a variably defined low ABI (≤0.95 or ≤0.99) showed no statistically significant effect of aspirin (100 mg daily) for composite CVD outcomes (adjusted hazard ratio [HR], 1.00 [95% CI, 0.81-1.23] and HR, 0.98 [95% CI, 0.76-1.26]). One trial (n = 3350) demonstrated no statistically significant increase in major bleeding events with the use of aspirin (adjusted HR, 1.71 [95% CI, 0.99- 2.97]) and no statistically significant increase in major gastrointestinal bleeding (relative risk, 1.13 [95% CI, 0.44-2.91]). Two exercise trials (n = 932) in screen-relevant populations reported no differences in quality of life, Walking Impairment Questionnaire walking distance, or symptoms at 12 and 52 weeks; no harms were reported.

CONCLUSIONS AND RELEVANCE

There was no direct evidence and limited indirect evidence on the benefits of PAD screening with the ABI in unselected or asymptomatic populations. Available studies suggest low sensitivity and lack of beneficial effect on health outcomes, but these studies have important limitations.

Cost-effectiveness of population-based vascular disease screening and intervention in men from the Viborg Vascular (VIVA) trial

Background

Population-based screening and intervention for abdominal aortic aneurysm, peripheral artery disease and hypertension was recently reported to reduce the relative risk of mortality among Danish men by 7 per cent. The aim of this study was to investigate the cost-effectiveness of vascular screening versus usual care (ad hoc primary care-based risk assessment) from a national health service perspective.

Methods

A cost-effectiveness evaluation was conducted alongside an RCT involving all men from a region in Denmark (50 156) who were allocated to screening (25 078) or no screening (25 078) and followed for up to 5 years. Mobile nurse teams provided screening locally and, for individuals with positive test results, referrals were made to general practices or hospital-based specialized centres for vascular surgery. Intention-to-treat-based, censoring-adjusted incremental costs (2014 euros), life-years and quality-adjusted life-years (QALYs) were estimated using Lin's average estimator method. Incremental net benefit was estimated using Willan's estimator and sensitivity analyses were conducted.

Results

The cost of screening was estimated at €148 (95 per cent c.i. 126 to 169), and the effectiveness at 0·022 (95 per cent c.i. 0·006 to 0·038) life-years and 0·069 (0·054 to 0·083) QALYs, generating average costs of €6872 per life-year and €2148 per QALY. At a willingness-to-pay threshold of €40 000 per QALY, the probabilities of cost-effectiveness were 98 and 99 per cent respectively. The probability of cost-effectiveness was 71 per cent when all the sensitivity analyses were combined into one conservative scenario.

Conclusion

Vascular screening appears to be cost-effective and compares favourably with current screening programmes.

Arachidonic Acid, but Not Omega-3 Index, Relates to the Prevalence and Progression of Abdominal Aortic Aneurysm in a Population-Based Study of Danish Men

Background

Animal models support dietary omega‐3 fatty acids protection against abdominal aortic aneurysm (AAA), but clinical data are scarce. The sum of red blood cell proportions of the omega‐3 eicosapentaenoic and docosahexaenoic acids, known as omega‐3 index, is a valid surrogate for long‐term omega‐3 intake. We investigated the association between the omega‐3 index and the prevalence and progression of AAA. We also investigated associations between AAA and arachidonic acid, an omega‐6 fatty acid that is a substrate for proinflammatory lipid mediators.

Methods and Results

We obtained blood samples from 498 AAA patients (maximal aortic diameter ≥30 mm) within a population‐based ultrasound‐screening trial in men and from 199 age‐matched controls who screened negative. We determined the fatty acids of red blood cells by gas chromatography. During a median follow‐up of 4.85 years, 141 AAA patients reached criteria for vascular surgical repair. Participants were high consumers of omega‐3 (average omega‐3 index: 7.6%). No significant associations were found for omega‐3 index. In contrast, arachidonic acid in AAA patients was higher than in controls (P<0.001), and individuals in the upper tertile of arachidonic acid at baseline had higher probability of having AAA (odds ratio: 1.309; 95% confidence interval, 1.021–1.678; P=0.033). AAA patients at the upper tertile of arachidonic acid at baseline had a 54% higher risk of needing surgical repair during follow‐up (hazard ratio: 1.544; 95% confidence interval, 1.127–2.114; P=0.007).

Conclusions

Omega‐3 index is unrelated to men with AAA from a country in which fish consumption is customarily high. Arachidonic acid is associated with AAA presence and progression.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00662480.

Population screening and intervention for vascular disease in Danish men (VIVA): a randomised controlled trial

BACKGROUND

Abdominal aortic aneurysm is the only cardiovascular disease targeted by population screening. In this study, we test the effect of screening and subsequent intervention for abdominal aortic aneurysm, peripheral arterial disease, and hypertension combined.

METHODS

In this randomised controlled trial, we randomly allocated (1:1) all men aged 65-74 years living in the Central Denmark Region to screening for abdominal aortic aneurysm, peripheral arterial disease, and hypertension, or to no screening. We based allocation on computer-generated random numbers from 1 to 100 in blocks of 1067 to 4392, stratified by 19 municipalities. Only the non-screening group and the investigator assessing outcomes were masked. We invited participants who were found to have abdominal aortic aneurysm or peripheral arterial disease back for confirmation and eventual initiation of relevant pharmacological therapy. We further offered participants with abdominal aortic aneurysm annual control or surgical repair. We referred participants with suspected hypertension to their general practitioner. The primary outcome was all-cause mortality, assessed 5 years after randomisation, analysed in all randomly allocated participants except for those who had incorrect person identification numbers. This trial is registered at ClinicalTrials.gov, number NCT00662480.

FINDINGS

Between Oct 8, 2008, and Jan 11, 2011, we randomly allocated 50 156 participants, with 25 078 (50%) each in the screening and non-screening groups. Four (<1%) participants in the screening group were lost to follow-up. After a median follow-up of 4·4 years (IQR 3·9-4·8), 2566 (10·2%) of 25 074 participants in the screening group and 2715 (10·8%) of 25 078 in the non-screening group had died. This finding resulted in a significant hazard ratio of 0·93 (95% CI 0·88-0·98; p=0·01), an absolute risk reduction of 0·006 (0·001-0·011), and a number needed to invite of 169 (89-1811). Incidences of diabetes (3995 per 100 000 person-years in the screening group vs 4129 per 100 000 person-years in the non-screening group), intracerebral haemorrhage (146 vs 140), renal failure (612 vs 649), cancer (3578 vs 3719), or 30 day mortality after cardiovascular surgery (44·57 vs 39·33) did not differ between groups.

INTERPRETATION

The observed reduction of mortality risk from abdominal aortic aneurysm, peripheral arterial disease, and hypertension has never been seen before in the population screening literature and can be linked primarily to initiation of pharmacological therapy. Health policy makers should consider implementing combined screening whether no screening or isolated abdominal aortic aneurysm screening is currently offered.

FUNDING

The 7th European Framework Programme, Central Denmark Region, Viborg Hospital, and the Danish Council for Independent Research.

The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice

AIM

The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques.

METHODS

AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- mice were developed and fed Western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process. In ApoE-/- and AQP1-/-ApoE-/- mice abdominal aortic aneurysms (AAA) were induced by angiotensin II (ANGII) infusion by osmotic minipumps for 4 weeks.

RESULTS

In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P < 0.003). Both in murine lesions at the aortic root and in the abdominal aortic aneurysmal wall, AQP1 immunoreactivity was associated with microvascular structures. The atherosclerotic lesion burden was enhanced significantly in ANGII-infused AQP1-/-ApoE-/- mice compared with ApoE-/- mice, but neither incidence nor progression of AAA was different. The aortic lesion burden increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes.

CONCLUSION

AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse arteries and AQP1 deficiency augments lesion development in ANGII-promoted atherosclerosis in mice. Normal function of AQP1 affords cardiovascular protection.

Magnetic resonance imaging of the intraluminal thrombus in abdominal aortic aneurysms: a quantitative and qualitative evaluation and correlation with growth rate

BACKGROUND

The role of the intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) growth remains incompletely understood. MRI is superior to other methods in depicting the morphology of the ILT. This study brings preliminary, but novel information on the presence and morphological characteristics of the ILT and AAA growth rates in a screening cohort.

METHODS

Cohort study with 46 patients from the Viborg Vascular Trial. All underwent one non-contrast-enhanced magnetic resonance imaging (MRI) at the end of follow-up. ILT presence was noted and, if present, it was allocated to one of four morphological categories based on visual appearance and signal intensity on T2 weighted images.

RESULTS

The mean growth rate was 1.95 mm/year ±0.87 (SD). The observation time was 5.59±0.63 (SD) years. ILT was present in AAA size groups as follows: 30-34.9 mm 20.00%, 35-39.9 mm 88.89%, 40-44.9 mm 81.25%, 45-49.9 mm 100% and 50-54.9 mm 100%. Out of 46, 8 had no ILT at the time of MRI. The presence of any sort of ILT yielded a significantly increased unadjusted and an adjusted growth rate of 1.09 mm/year (95% CI: 0.48; 1.70) and 1.24 mm/year (95% CI: 0.64; 1.83), respectively. All four thrombus types were retrospectively associated with an increased recorded growth rate compared with "no thrombus". Presence of a thin circumferential thrombus was retrospectively associated with the highest increase in growth rate, viz. 2.09 mm/year (95% CI: 1.23; 2.95).

CONCLUSIONS

We observed faster growth rate in those AAA that had developed an ILT. Even faster growth was observed amongst those AAA containing a thin ILT located along the inner circumference.

Association of ficolin-3 with abdominal aortic aneurysm presence and progression

Essentials Abdominal aortic aneurysm (AAA) is asymptomatic and its evolution unpredictable. To find novel potential biomarkers of AAA, microvesicles are an excellent source of biomarkers. Ficolin-3 is increased in microvesicles obtained from activated platelets and AAA tissue. Increased ficolin-3 plasma levels are associated with AAA presence and progression.

SUMMARY

Background Abdominal aortic aneurysm (AAA) patients are usually asymptomatic and AAA evolution is unpredictable. Ficolin-3, mainly synthesized by the liver, is a molecule of the lectin complement-activation pathway involved in AAA pathophysiology. Objectives To define extra-hepatic sources of ficolin-3 in AAA and investigate the role of ficolin-3 as a biomarker of the presence and progression of AAA. Methods Microvesicles (exosomes and microparticles) were isolated from culture-conditioned medium of ADP-activated platelets, as well as from AAA tissue-conditioned medium (thrombus and wall). Ficolin-3 levels were analyzed by western-blot, real-time PCR, immunohistochemistry and ELISA. Results Increased ficolin-3 levels were observed in microvesicles isolated from activated platelets. Similarly, microvesicles released from AAA tissue display increased ficolin-3 levels as compared with those from healthy tissue. Moreover, ficolin-3 mRNA levels in the AAA wall were greatly increased compared with healthy aortic walls. Immunohistochemistry of AAA tissue demonstrated increased ficolin-3, whereas little staining was present in healthy walls. Finally, increased ficolin-3 levels were observed in AAA patients' plasma (n = 478) compared with control plasma (n = 176), which persisted after adjustment for risk factors (adjusted odds ratio [OR], 5.29; 95% confidence interval [CI], 3.27, 8.57)]. Moreover, a positive association of ficolin-3 with aortic diameter (Rho, 0.25) and need for surgical repair was observed, also after adjustment for potential confounding factors (adjusted hazard ratio, 1.55; 95% CI, 1.11, 2.15). Conclusions In addition to its hepatic expression, ficolin-3 may be released into the extracellular medium via microvesicles, by both activated cells and pathological AAA tissue. Ficolin-3 plasma levels are associated with the presence and progression of AAA, suggesting its potential role as a biomarker of AAA.

Glycated Hemoglobin Is Associated With the Growth Rate of Abdominal Aortic Aneurysms: A Substudy From the VIVA (Viborg Vascular) Randomized Screening Trial

OBJECTIVE

An inverse association between abdominal aortic aneurysms (AAAs) and diabetes mellitus exists; however, the cause remains unknown. This study aimed to evaluate whether the degree of glycemia is associated with aneurysm growth.

APPROACH AND RESULTS

The study was based on VIVA trial (Viborg Vascular), the randomized clinically controlled screening trial for abdominal aortic aneurysm in men aged 65 to 74 years in the Central Denmark Region. The screening included measurement of the abdominal aorta by ultrasound, analysis of glycated hemoglobin (HbA1c), and follow-up for ≤5 years for aneurysms <5 cm. Analyses were conducted using mixed-effect models. At baseline, VIVA screening identified 619 individuals (3.3%) with abdominal aortic aneurysms. A total of 103 individuals were referred for vascular evaluation, and after removal of additional individuals who were lost to follow-up or had missing blood samples, we were left with 319 individuals. Sixty-one individuals (19.1%) had diabetes mellitus. The median growth rate was 1.7 versus 2.7 mm/y in individuals with and without diabetes mellitus, respectively (P<0.001). We found a significant inverse association between aneurysmal growth rate and HbA1c in the total study population (P=0.002). Both crude and adjusted analyses identified slower growth for the group with the highest HbA1c tertile compared with the lowest HbA1c tertile. After 3 years, the mean difference was 1.8 mm (confidence interval, 0.98-2.64). Similar significant differences were observed in subgroup analysis of individuals without self-reported diabetes mellitus.

CONCLUSIONS

We found an inverse association between the growth rate of abdominal aortic aneurysms and the level of HbA1c, indicating that long-lasting elevated blood sugar impairs aneurysmal progression in individuals with and without known diabetes mellitus.

Pulse palpation is an effective method for population-based screening to exclude peripheral arterial disease

OBJECTIVE

There is a strong association between peripheral arterial disease (PAD) and future cardiovascular events. Therefore, intensive atherosclerotic risk factor reduction is recommended for people with PAD, and early detection is essential. This study assessed whether systematic pedal pulse palpation is an effective screening method for PAD in population-based screening programs.

METHODS

As part of a randomized screening project, The Viborg Vascular Screening trial, 18,681 men (mean age, 69.3 years; range, 65-74 years) participated in a screening program, which included bilateral pulse palpation and ankle-brachial index (ABI) measurement. PAD was defined as ABI ≤0.9 or ≥1.4. Analysis was conducted on sensitivity, specificity, positive predictive value, and negative predictive value for PAD and for the number of pedal pulses.

RESULTS

PAD was present in 2215 participants (12.1%). The pedal pulse palpation test was set to be positive for having PAD if one or more pulses were missing. Sensitivity was 71.7% and specificity was 72.3%. No palpable pulses were associated with a 50% chance of ABI-verified PAD or with a false finding. Four palpable pulses were associated with 5% false-negative PAD cases.

CONCLUSIONS

Pedal pulse palpation is was shown to be a reliable initial screening tool for PAD in population-based programs but only when four pedal pulses were present. Therefore, ABI measurement should routinely be measured in patients with fewer than four palpable pedal pulses so cardiovascular preventive actions can be initiated if PAD is confirmed.

Asthma Associates With Human Abdominal Aortic Aneurysm and Rupture

OBJECTIVE

Both asthma and abdominal aortic aneurysms (AAA) involve inflammation. It remains unknown whether these diseases interact.

APPROACH AND RESULTS

Databases analyzed included Danish National Registry of Patients, a population-based nationwide case-control study included all patients with ruptured AAA and age- and sex-matched AAA controls without rupture in Denmark from 1996 to 2012; Viborg vascular trial, subgroup study of participants from the population-based randomized Viborg vascular screening trial. Patients with asthma were categorized by hospital diagnosis, bronchodilator use, and the recorded use of other anti-asthma prescription medications. Logistic regression models were fitted to determine whether asthma associated with the risk of ruptured AAA in Danish National Registry of Patients and an independent risk of having an AAA at screening in the Viborg vascular trial. From the Danish National Registry of Patients study, asthma diagnosed <1 year or 6 months before the index date increased the risk of AAA rupture before (odds ratio [OR]=1.60-2.12) and after (OR=1.51-2.06) adjusting for AAA comorbidities. Use of bronchodilators elevated the risk of AAA rupture from ever use to within 90 days from the index date, before (OR=1.10-1.37) and after (OR=1.10-1.31) adjustment. Patients prescribed anti-asthma drugs also showed an increased risk of rupture before (OR=1.12-1.79) and after (OR=1.09-1.48) the same adjustment. In Viborg vascular trial, anti-asthmatic medication use associated with increased risk of AAA before (OR=1.45) or after adjustment for smoking (OR=1.45) or other risk factors (OR=1.46).

CONCLUSIONS

Recent active asthma increased risk of AAA and ruptured AAA. These findings document and furnish novel links between airway disease and AAA, 2 common diseases that share inflammatory aspects.

The Provision of Interventional Radiology Services in Europe: CIRSE Recommendations

Interventional Radiology (IR) is an essential part of modern medicine, delivering minimally invasive patient-focused care, which has been proven to be safe and effective in both elective and emergency settings. The aim of this document is to outline the core requirements and standards for the provision of Interventional Radiological services, including training, certification, manpower, and accreditation. The ultimate challenge will be the adoption of these recommendations by different countries and health economies around the world, in turn ensuring equal access to IR treatments for all patients, the appropriate distribution of resources for IR service provision as well as the continued development of safe and high-quality IR services in Europe and beyond.

The Danish Cardiovascular Screening Trial (DANCAVAS): study protocol for a randomized controlled trial

Background

The significant increase in the average life expectancy has increased the societal challenge of managing serious age-related diseases, especially cancer and cardiovascular diseases. A routine check by a general practitioner is not sufficient to detect incipient cardiovascular disease.

Design

Population-based randomized clinically controlled screening trial.

Methods

Participants: 45,000 Danish men aged 65–74 years living on the Island of Funen, or in the surrounding communities of Vejle and Silkeborg. No exclusion criteria are used.

Interventions: One-third will be invited to cardiovascular seven-faceted screening examinations at one of four locations. The screening will include: (1) low-dose non-contrast CT scan to detect coronary artery calcification and aortic/iliac aneurysms, (2) brachial and ankle blood pressure index to detect peripheral arterial disease and hypertension, (3) a telemetric assessment of the heart rhythm, and (4) a measurement of the cholesterol and plasma glucose levels. Up-to-date cardiovascular preventive treatment is recommended in case of positive findings.

Objective: To investigate whether advanced cardiovascular screening will prevent death and cardiovascular events, and whether the possible health benefits are cost effective.

Outcome: Registry-based follow-up on all cause death (primary outcome), and costs after 3, 5 and 10 years (secondary outcome).

Randomization: Each of the 45,000 individuals is, by EPIDATA, given a random number from 1–100. Those numbered 67+ will be offered screening; the others will act as a control group.

Blinding: Only those randomized to the screening will be invited to the examination;the remaining participants will not.

Numbers randomized: A total of 45,000 men will be randomized 1:2.

Recruitment: Enrollment started October 2014.

Outcome: A 5 % reduction in overall mortality (HR = 0.95), with the risk for a type 1 error = 5 % and the risk for a type II error = 80 %, is expected. We expect a 2-year enrollment, a 10-year follow-up, and a median survival of 15 years among the controls. The attendance to screening is assumed to be 70 %.

Discussion

The primary aim of this so far stand-alone population-based, randomized trial will be to evaluate the health benefits and costeffectiveness of using non-contrast full truncus computer tomography (CT) scans (to measure coronary artery calcification (CAC) and identify aortic/iliac aneurysms) and measurements of the ankle brachial blood pressure index (ABI) as part of a multifocal screening and intervention program for CVD in men aged 65–74.

Attendance rate and compliance to initiated preventive actions must be expected to become of major importance.

Trial registration

Current Controlled Trials: ISRCTN12157806 (21 March 2015).

Hemoglobin induces monocyte recruitment and CD163-macrophage polarization in abdominal aortic aneurysm

BACKGROUND

Increased hemoglobin (Hb) accumulation was reported in abdominal aortic aneurysms (AAAs). CD163 is a macrophage receptor involved in tissue Hb clearance, however its role in AAA has not been reported. We investigated the role of Hb on monocyte recruitment and differentiation towards CD163 expressing macrophages ex vivo, in vitro and in human AAA.

METHODS AND RESULTS

CD163 mRNA and protein expression was significantly higher in human AAA (n=7) vs. healthy wall (n=6). CD163 was predominantly found in adventitia of AAA, coinciding with areas rich in hemosiderin and adjacent to neoangiogenic microvessels. Dual CD14/CD163 expression was observed in recently infiltrated monocytes surrounding microvessels. A higher release of soluble CD163 was observed in the conditioned medium from AAA (AAA-CM, n=10), mainly in the adventitial layer. Similar to Hb, AAA-CM induced CD163-dependent monocyte chemotaxis, especially on circulating monocytes from AAA patients. Hb or AAA-CM promoted differentiation towards CD163(high)/HLA-DR(low)-expressing macrophages, with enhanced Hb uptake, increased anti-inflammatory IL-10 secretion and decreased pro-inflammatory IL-12p40 release. All these effects were partially suppressed when Hb was removed from AAA-CM. Separate analysis on circulating monocytes reported increased percentage of pre-infiltrating CD14(++)CD16(+) monocytes in patients with AAA (n=21), as compared to controls (n=14). A significant increase in CD163 expression in CD14(++)CD16(+) monocyte subpopulation was observed in AAA patients.

CONCLUSIONS

The presence of Hb in the adventitial AAA-wall promotes the migration and differentiation of activated circulating monocytes in AAA patients, explaining the existence of a protective CD163-macrophage phenotype that could take up the Hb present in the AAA-wall, avoiding its injurious effects.

Plasma cytokine levels and risks of abdominal aortic aneurysms: A population-based prospective cohort study

BACKGROUND

Abdominal aortic aneurysm (AAA) is characterized by inflammatory cell accumulation in AAA lesions that produce inflammatory cytokines and advance its pathogenesis. Peripheral cytokines may predict the degree or risk of AAA.

METHODS AND RESULTS

ELISA determined plasma interleukin-6 (IL6), IL10, IL17A, IFN-γ, and C-reactive protein (CRP) from 476 AAA patients and 200 controls. AAA patients had lower IL6, IFN-γ, IL10, IL17A, and higher CRP than controls. IL10 correlated positively with IFN-γ, IL17A, or IL6, but not CRP in control or AAA populations. IL10 associated negatively with systolic blood pressure, whereas CRP associated positively with diastolic blood pressure and body mass index. CRP was an independent AAA risk factor and correlated positively with aortic diameters before and after adjustments for other risk factors. IFN-γ, IL17A, and CRP correlated positively with cross-sectional AAA area after adjustment. IL10 correlated positively with AAA growth rate before and after adjustment. The risk of death doubled in AAA patients with CRP levels above the median.

CONCLUSIONS

Reduced IFN-γ, IL10, and IL17A in AAA patients, positive correlations of IFN-γ and IL17A with cross-sectional AAA area, IL10 with AAA growth rate, and IL10 with IFN-γ and IL17A suggest combined Th1, Th2, and Th17 immune responses in human AAAs.

Baseline prevalence of abdominal aortic aneurysm, peripheral arterial disease and hypertension in men aged 65–74 years from a population screening study (VIVA trial)

Background

Abdominal aortic aneurysm (AAA) screening has been introduced into some health systems and could easily be supplemented with broader vascular screening. The aim of this study was to evaluate the screening set-up and investigate combined screening for AAA, peripheral arterial disease (PAD) and possible hypertension (HT), and detection rates.

Methods

This observational study was based on the intervention arm of a screening trial in 25 083 Danish men aged 65–74 years. A combined screening programme for AAA, PAD and HT was offered at local hospitals. Participants with positive test results were offered secondary prophylaxis and/or referred to their general practitioner. The programme set-up included decentralized screening by three mobile teams at 14 venues. Diagnostic criteria were: aortic diameter at least 30 mm for AAA, ankle : brachial pressure index below 0·9 or above 1·4 for PAD, and BP exceeding 160/100 mmHg for HT.

Results

Overall, 18 749 men (uptake 74·7 per cent) attended the screening. An AAA was diagnosed in 3·3 (95 per cent c.i. 3·0 to 3·6) per cent, PAD in 10·9 (10·5 to 11·4) per cent and HT in 10·5 (10·0 to 10·9) per cent. Lipid-lowering and/or antiplatelet treatment was initiated in 34·8 per cent of the participants.

Conclusion

Preventive actions were started in one-third of the attenders. The long-term effect of this on morbidity and mortality is an important part of future analysis. The trial confirms that the prevalence of AAA in Denmark has decreased only slightly in the past decade, from 4·0 to 3·3 per cent, in contrast to other nations.

IgE actions on CD4+ T cells, mast cells, and macrophages participate in the pathogenesis of experimental abdominal aortic aneurysms

Immunoglobulin E (IgE) activates mast cells (MCs). It remains unknown whether IgE also activates other inflammatory cells, and contributes to the pathogenesis of abdominal aortic aneurysms (AAAs). This study demonstrates that CD4⁺ T cells express IgE receptor FcεR1, at much higher levels than do CD8⁺ T cells. IgE induces CD4⁺ T-cell production of IL6 and IFN-γ, but reduces their production of IL10. FcεR1 deficiency (Fcer1a^−/−) protects apolipoprotein E-deficient (Apoe^−/−) mice from angiotensin-II infusion-induced AAAs and reduces plasma IL6 levels. Adoptive transfer of CD4⁺ T cells (but not CD8⁺ T cells), MCs, and macrophages from Apoe^−/− mice, but not those from Apoe^−/−Fcer1a^−/− mice, increases AAA size and plasma IL6 in Apoe^−/−Fcer1a^−/− recipient mice. Biweekly intravenous administration of an anti-IgE monoclonal antibody ablated plasma IgE and reduced AAAs in Apoe^−/− mice. Patients with AAAs had significantly higher plasma IgE levels than those without AAAs. This study establishes an important role of IgE in AAA pathogenesis by activating CD4⁺ T cells, MCs, and macrophages and supports consideration of neutralizing plasma IgE in the therapeutics of human AAAs.

Scientific second-order 'nudging' or lobbying by interest groups: the battle over abdominal aortic aneurysm screening programmes

The idea that it is acceptable to 'nudge' people to opt for the 'healthy choice' is gaining currency in health care policy circles. This article investigates whether researchers evaluating Abdominal Aortic Aneurysm Screening Programmes (AAASP) attempt to influence decision makers in ways that are similar to popular 'nudging' techniques. Comparing two papers on the health economics of AAASP both published in the BMJ within the last 3 years, it is shown that the values chosen for the health economics modelling are not representative of the literature and consistently favour the conclusions of the articles. It is argued (1) that this and other features of these articles may be justified within a Libertarian Paternalist framework as 'nudging' like ways of influencing decision makers, but also (2) that these ways of influencing decision makers raise significant ethical issues in the context of democratic decision making.

Abdominal aortic diameter is increased in males with a family history of abdominal aortic aneurysms: results from the Danish VIVA-trial

OBJECTIVE

To investigate, at a population level, whether a family history of abdominal aortic aneurysm (AAA) is independently related to increased aortic diameter and prevalence of AAA in men, and to elucidate whether the mean aortic diameter and the prevalence of AAA are different between participants with male and female relatives with AAA.

DESIGN

Observational population-based cross-sectional study.

MATERIALS

18,614 male participants screened for AAA in the VIVA-trial 2008-2011 with information on both family history of AAA and maximal aortic diameter.

METHODS

Standardized ultrasound scan measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication.

RESULTS

From the screened cohort, 569 participants had at least one first degree relative diagnosed with AAA, and 38 had AAA. Participants with a family history of AAA (+FH) had a significantly larger mean maximum aortic diameter (20.50 mm) compared with participants without family history of AAA (-FH) (19.07 mm, p < .0001), and +FH with female relatives with AAA had significantly larger mean maximum aortic diameter (21.8 mm) than +FH with male relatives (19.9 mm, p = .007). Furthermore the prevalence of AAA was significantly higher among +FH (6.7%) compared with -FH (3.0%) with an odds ratio (OR) of 2.2 (95% CI: 1.6 to 3.2, p < .001) and +FH with female relatives with AAA had a more than two and a half times increased prevalence of AAA compared with +FH with male relatives with AAA with an OR of 2.65.

CONCLUSIONS

First-degree male relatives of AAA patients have wider aortas and a twofold higher prevalence of AAA compared with the age adjusted background population. The prevalence of AAA was markedly higher in participants related to female, rather than male, patients with AAA.

Screening for peripheral arterial disease

BACKGROUND

In the general population, up to 10% of people younger than 70 years and 15% to 20% of people older than 70 years have peripheral arterial disease (PAD). Symptomatic and asymptomatic PAD has an estimated prevalence of 13% in the over 50 years age group. However, asymptomatic PAD can account for up to 75% of PAD patients and only 10% of PAD patients have typical intermittent claudication. People with PAD are at an increased risk of death, heart and cerebrovascular disease and are recommended to receive treatment to manage their cardiac risk. They suffer from significant functional limitations in their daily activities and the most severely affected are at risk of limb loss. Many people with PAD do not have any symptoms. Only some people have discomfort or pain in the lower legs when walking, so PAD often goes undetected. Given the high incidence of asymptomatic and undiagnosed PAD, it is important to determine the effectiveness of a screening intervention in preventing cardiovascular adverse outcomes, both fatal and non-fatal.

OBJECTIVES

To determine the effectiveness of screening for PAD in asymptomatic and undiagnosed individuals in terms of reduction of all-cause mortality, cardiovascular events (for example myocardial infarction and stroke), morbidity from PAD (intermittent claudication, amputation, reduced walking distance) and improvement in quality of life.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched November 2013) and CENTRAL (2013, Issue 10).

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of screening for PAD were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion in the review were independently assessed by both review authors. We planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Review of Interventions.

MAIN RESULTS

No RCTs were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

Unfortunately, no randomised controlled trial data are available regarding screening for PAD. Therefore, we are unable to determine the effects of screening for PAD in order to guide decision making by healthcare providers and planners. High quality randomised controlled trials evaluating the effectiveness of screening for PAD in asymptomatic and undiagnosed individuals in terms of reduction of all-cause mortality, cardiovascular events (for example myocardial infarction and stroke), morbidity from PAD (intermittent claudication, amputation, reduced walking distance) and improvement in quality of life are needed.

Novices may be trained to screen for abdominal aortic aneurysms using ultrasound

Background

Highly trained vascular sonographers make up a significant cost of abdominal aortic aneurysm (AAA) ultrasound screening. However, they are over-trained for this very limited task. Others have reported that health workers (e.g. emergency room staff and nurses) with far less training may be able to perform these scans. The national AAA screening programme in the UK uses staff with limited training. Whether individuals without a health professional qualification could be trained to perform the scan accurately to improve cost-effectiveness is not known. We aimed to investigate whether a short, well-supervised course in ultrasonography could train novices to detect AAA for screening purposes.

Methods

Three novices were trained by an experienced sonographer for 15 days to perform abdominal aortic ultrasound examinations and detect AAA using a portable ultrasound system. The examination included four anterior-posterior aortic measurements: a maximal diameter in the coronal plane and three diameters of the suprarenal, mid and distal infrarenal aorta in the transverse plane. The novices independently scanned 215 subjects following training; experienced sonographers repeated the measurements on the same subject in the same session. Using Bland-Altman plots and CUSUM analysis, the novices’ and experienced sonographers’ accuracy and efficiency measurements were compared. Factors influencing performance were recorded.

Results

The novices measured the maximal coronal aortic diameter accurately, to within 0.46-0.52 cm of the true diameter; 85-97% of their coronal measurements were within 0.5 cm of the assessors; kappa statistic and Bland-Altman plots show a high agreement with the assessor’s measurements. However, the novices’ measurements of the three diameters in the transverse plane were outside clinically acceptable limits. Assuming a referral policy for a second scan for scans recorded as 'difficult’, only one novice missed a 3.13 cm aneurysm.

A CUSUM quality improvement analysis demonstrated substantial improvements in the scanning efficiency of the novices with continued scanning experience.

Conclusion

This study showed that novices could be trained to screen for AAA over 15 days. However, the need for continuing quality improvement is critical, especially in more technically demanding cases. Measuring the maximal infrarenal diameter instead of specific segmental diameters may be more appropriate for AAA screening using novices.

Lack of association between inguinal hernia and abdominal aortic aneurysm in a population-based male cohort

Background

Previous studies have reported a higher prevalence of inguinal hernia in patients with abdominal aortic aneurysm (AAA). The aim of this study was to explore the association between inguinal hernia and AAA in a large population-based cohort of men who had screening for AAA.

Methods

A total of 18 331 men aged 65–76 years had ultrasound screening for AAA in the Central Region of Denmark from 2008 to 2010. The Danish National Patient Registry was interrogated, and screened men registered with an inguinal hernia from 1977 to 2011 were identified. The association between inguinal hernia and AAA was assessed by multiple logistic regression analysis.

Results

The prevalence of AAA was 3.3 per cent (601 of 18 331). A total of 2936 (16.0 per cent) of the 18 331 patients were registered with a diagnosis of inguinal hernia or hernia repair. Inguinal hernia was not associated with AAA: crude odds ratio (OR) 0.86 (95 per cent confidence interval 0.68 to 1.09) and adjusted OR 0.94 (0.75 to 1.20).

Conclusion

In contrast to smaller patient-based studies, this large population-based study found no association between inguinal hernia and AAA.

Plasma levels of cathepsins L, K, and V and risks of abdominal aortic aneurysms: a randomized population-based study

BACKGROUND

Cathepsin L (CatL), cathepsin K (CatK), and cathepsin V (CatV) are potent elastases implicated in human arterial wall remodeling. Whether plasma levels of these cathepsins are altered in patients with abdominal aortic aneurysms (AAAs) remains unknown.

METHODS AND RESULTS

Plasma samples were collected from 476 male AAA patients and 200 age-matched male controls to determine CatL, CatK, and CatV levels by ELISA. Student's t-test demonstrated significantly higher plasma CatL levels in AAA patients than in controls (P < 0.0001), whereas CatK and CatV levels were lower in AAA patients than in controls (P = 0.052, P = 0.025). ROC curve analysis confirmed higher plasma CatL levels in AAA patients than in controls (P < 0.001). As potential confounders, current smoking and use of angiotensin-converting enzyme (ACE) inhibitors, aspirin, clopidogrel, and statins associated with significantly increased plasma CatL. Pearson's correlation test demonstrated that plasma CatL associated positively with CatS (r = 0.43, P < 0.0001), body-mass index (BMI) (r = 0.07, P = 0.047) and maximal aortic diameter (r = 0.29, P < 0.001), and negatively with lowest measured ankle-brachial index (ABI) (r = -0.22, P < 0.001). Plasma CatL remained associated positively with CatS (r = 0.43, P < 0.0001) and aortic diameter (r = 0.212, P < 0.001) and negatively with ABI (r = -0.10, P = 0.011) after adjusting for the aforementioned potential confounders in a partial correlation analysis. Multivariate logistic regression analysis indicated that plasma CatL was a risk factor of AAA before (odds ratio [OR] = 3.04, P < 0.001) and after (OR = 2.42, P < 0.001) the same confounder adjustment.

CONCLUSIONS

Correlation of plasma CatL levels with aortic diameter and the lowest ABI suggest that this cysteinyl protease plays a detrimental role in the pathogenesis of human peripheral arterial diseases and AAAs.

Individual decision making in relation to participation in cardiovascular screening: a study of revealed and stated preferences

AIMS

The (cost-)effectiveness of a screening programme may be strongly influenced by the participation rate. The objective of this study was to compare participants' and non-participants' motives for the attendance decision as well as their overall preferences for participation in cardiovascular disease screening.

METHODS

This study sampled 1053 participants and 1006 non-participants from a screening trial and randomly allocated the participants to receive different levels of additional information about the screening programme. An ad hoc survey questionnaire about doubt and arguments in relation to the participation decision was given to participants and non-participants along with a contingent valuation task.

RESULTS

Among participants, 5% had doubt about participation and the most frequent argument was that they did not want the test result. Among non-participants, 40% would reconsider their non-participation decision after having received additional information while the remainder 60% stood by their decision and provided explicit arguments for it. After having received additional information the participants still valued the programme significantly higher than non-participants, but the difference was relatively small.

CONCLUSIONS

Participants and non-participants in cardiovascular screening programmes seem to have different strengths of preferences, which signals that their behavioural choice is founded in rational thinking. Furthermore, it appears that additional information and a second reflection about the participation decision may affect a substantial proportion of non-participants to reverse their decision, a finding that should receive policy interest.

Insensitivity to scope in contingent valuation studies: reason for dismissal of valuations?

BACKGROUND

The credibility of contingent valuation studies has been questioned because of the potential occurrence of scope insensitivity, i.e. that respondents do not react to higher quantities or qualities of a good.

OBJECTIVE

The aim of this study was to examine the extent of scope insensitivity and to assess the relevance of potential explanations that may help to shed light on how to appropriately handle this problem in contingent valuation studies.

METHODS

We surveyed a sample of 2004 men invited for cardiovascular disease screening. Each respondent had three contingent valuation tasks from which their sensitivity to larger risk reductions (test 1) and to change in travel costs associated with participation (test 2) could be assessed. Participants were surveyed while waiting for their screening session. Non-participants were surveyed by postal questionnaire.

RESULTS

The sample was overall found to be sensitive to scope, testing at the conventional sample-mean level. At the individual respondent level, however, more than half of the respondents failed the tests. Potential determinants for failing the tests were examined in alternative regression models but few consistent relationships were identified. One exception was the influence of more detailed information, which was positively associated with willingness to pay and negatively associated with scope sensitivity.

CONCLUSION

Possible explanations for scope insensitivity are discussed; if cognitive limitations, emotional load and mental budgeting explain scope insensitivity there are grounds for rejecting valuations, whereas other factors such as the alternative theoretical framework of regret theory may render insensitivity to scope a result of rational thinking. It is concluded that future contingent valuation studies should focus more on extracting the underlying motives for the stated preferences in order to appropriately deal with responses that are seemingly irrational, and which may lead to imprecise welfare estimates.

Plasma cathepsin S and cystatin C levels and risk of abdominal aortic aneurysm: a randomized population-based study

BACKGROUND

Human abdominal aortic aneurysm (AAA) lesions contain high levels of cathepsin S (CatS), but are deficient in its inhibitor, cystatin C. Whether plasma CatS and cystatin C levels are also altered in AAA patients remains unknown.

METHODS AND RESULTS

Plasma samples were collected from 476 male AAA patients and 200 age-matched male controls to determine CatS and cystatin C levels by ELISA. Student's t test demonstrated higher plasma levels of total, active, and pro-CatS in AAA patients than in controls (P<0.001). ROC curve analysis confirmed higher plasma total, active, and pro-CatS levels in AAA patients than in controls (P<0.001). Logistic regression suggested that plasma total (odds ratio [OR] = 1.332), active (OR = 1.21), and pro-CatS (OR = 1.25) levels were independent AAA risk factors that associated positively with AAA (P<0.001). Plasma cystatin C levels associated significantly, but negatively, with AAA (OR = 0.356, P<0.001). Univariate correlation demonstrated that plasma total and active CatS levels correlated positively with body-mass index, diastolic blood pressure, and aortic diameter, but negatively with the lowest ankle-brachial index (ABI). Plasma cystatin C levels also correlated negatively with the lowest ABI. Multivariate linear regression showed that plasma total, active, and pro-CatS levels correlated positively with aortic diameter and negatively with the lowest ABI, whereas plasma cystatin C levels correlated negatively with aortic diameter and the lowest ABI, after adjusting for common AAA risk factors.

CONCLUSIONS

Correlation of plasma CatS and cystatin C with aortic diameter and the lowest ABI suggest these serological parameters as biomarkers for human peripheral arterial diseases and AAA.