Comparison of three targeted approaches to screening for abdominal aortic aneurysm based on cardiovascular risk

Association between lipoprotein(a), LPA genetic risk score, aortic valve disease, and subsequent major adverse cardiovascular events

AIMS

Cohort studies have demonstrated associations between calcific aortic valve disease (CAVD) and Lp(a). As Lp(a) is almost entirely genetically determined, in this study, we aim to determine whether Lp(a), when predicted from genetic data, is associated with CAVD and major adverse cardiovascular events (MACEs).

METHODS AND RESULTS

Patients undergoing coronary angiography between January 2012 and May 2013 were invited to participate in the study. Of 752 analysable participants, 446 had their Lp(a) measured and 703 had a calculable LPA genetic risk score (GRS). The primary outcomes were the presence of CAVD at baseline and MACE over a 7-year follow-up. The GRS explained 45% of variation in Lp(a). After adjustment for cardiac risk factors and coronary artery disease (CAD), the odds of CAVD increased with increasing Lp(a) [odds ratio (OR) 1.039 per 10-unit increase, 95% confidence interval (CI) 1.022-1.057, P < 0.001] and GRS (OR 1.054 per 10-unit increase, 95% CI 1.024-1.086; P < 0.001). Lipoprotein(a) and the GRS as continuous variables were not associated with subsequent MACEs. A dichotomized GRS (>54) was associated with MACE, but this relationship became non-significant when CAD classification was added into the model (OR 1.333, 95% CI 0.927-1.912; P = 0.12).

CONCLUSION

An LPA GRS can explain 45% of variation in Lp(a) levels, and both Lp(a) and the GRS are associated with CAVD. An elevated GRS is associated with future cardiac events in a secondary risk setting, but, if the CAD status is known, it does not provide additional prognostic information.

Brazilian Society for Angiology and Vascular Surgery guidelines on abdominal aortic aneurysm

The Brazilian Society of Angiology and Vascular Surgery, through the Guidelines Project, presents new Abdominal Aortic Aneurysm Guidelines, on the subject of care for abdominal aortic aneurysm patients. Its development prioritized descriptive guidelines, using the EMBASE, LILACS, and PubMed databases. References include randomized controlled trials, systematic reviews, meta-analyses, and cohort studies. Quality of evidence was evaluated by a pair of coordinators, aided by the RoB 2 Cochrane tool and the Newcastle Ottawa Scale forms. The subjects include juxtarenal aneurysms, infected aneurysms, and new therapeutic techniques, especially endovascular procedures. The current version of the guidelines include important recommendations for the primary topics involving diagnosis, treatment, and follow-up for abdominal aortic aneurysm patients, providing an objective guide for medical practice, based on scientific evidence and widely available throughout Brazil.

Predictors of Five-Year Survival after EVAR: 10-Year Experience of Single-Center Cohort Study

BACKGROUND

Endovascular abdominal aortic repair (EVAR) is the main therapeutic option for repairing abdominal aortic aneurysms (AAAs). We aimed to determine the long-term outcomes of patients who underwent EVAR at our center.

METHODS

In this retrospective cohort study, patients who underwent EVAR for intact isolated AAA at Tehran Heart Center between 2007 and 2017 were included. Clinical outcomes and the frequency of mortality were analyzed for follow-up periods. We calculated the 5-year survival rate and its predictors for our patients using Kaplan-Meier estimation.

RESULTS

We included the data of all patients (154 patients, mean age = 70.7 [± 8.0] years, 96.1% men) who successfully underwent EVAR at our center. The most common risk factors were coronary artery disease (70.1%), hypertension (68.2%), smoking (64.9%), and dyslipidemia (39.6%). There was no mortality during the procedure. The median follow-up was 65.5 months. An average decrease of 9.07 mm (95% confidence interval: 6.9-11.2) occurred in the size of the AAA. During follow-up, 12 patients developed some complications, 49 died, and 7 did not complete the follow-up. The 5-year survival rate was 75% (3.9%). The independent predictors for 5-year survival were age (hazard ratio [HR] = 1.06, P = 0.002) and anemia (HR = 1.91, P = 0.029). Despite not being statistically significant, dyslipidemia (HR = 0.573, P = 0.078) and long intensive care unit/cardiac care unit stays (HR = 1.08, P = 0.070) were borderline mortality predictors.

CONCLUSIONS

This study depicted an acceptable survival rate for patients who underwent EVAR at our center. Age and anemia, 2 modifiable predictors of 5-year survival, can probably prolong the survival rate of patients, which requires evaluation later.

The Fate of Patients Opportunistically Screened for Abdominal Aortic Aneurysms During Echocardiogram or Arterial Duplex Scans

OBJECTIVE

To evaluate the long term outcomes of individuals who attended for transthoracic echocardiograms (TTEs) or lower limb arterial duplex scans (LLADS) and were opportunistically screened for abdominal aortic aneurysms (AAA).

METHODS

Follow up of a prospective single centre pilot cohort study conducted between December 2012 and September 2014 at a tertiary vascular centre in the United Kingdom. Men and Women aged 65 and over were invited to undergo AAA screening when attending hospital for TTE or LLADS. Screening was performed by ultrasonographic examination of the abdomen at the end of their planned scans. AAA was defined as an abdominal aorta outer wall to outer wall anteroposterior diameter of 30 mm or more. Patients were excluded if they had a known AAA or previous abdominal aorta intervention. Follow up outcomes were evaluated in December 2020.

RESULTS

762 patients were enrolled in this study; 486 had TTE and 276 patients had LLADS. The overall incidence of AAA was 54 (7.1%) in the combined cohort, 25 (5.1%) in the TTE group, and 29 (10.5%) in the LLADS group. After a median 7.6 years, two of the 54 AAAs received intervention in the form of endovascular repair. Three others reached treatment threshold but were managed conservatively. The overall intervention rate was 3.7% of detected AAAs. Adjusted mortality rates in those with AAA vs. without was 64.8% and 36%, respectively (hazard ratio [HR] 2.02, p < .001). Diabetes (HR 1.35, p = .015) and older age (HR 1.18, p = .17) were the other factors associated with death.

CONCLUSION

AAA is associated with a significantly increased mortality rate. Populations attending hospital for TTE or LLADS demonstrate a higher prevalence of AAA than population based screening; however, the proportion offered AAA intervention was low. Further research into opportunistic screening should target those more likely to undergo AAA repair, unless other interventions are demonstrated, to reduce the general increased mortality in AAA patients.

Use of radiological information system data in Clinical Portal database to screen for missed abdominal aortic aneurysms

INTRODUCTION

New Zealand lacks a formal abdominal aortic aneurysm screening programme and owing to its rural nature, many patients have limited access to vascular surgery. Patients with vascular emergencies often have limited treatment options locally, especially if they present perimortem. In our small hospital in Whanganui, with the nearest vascular centre more than 150km away, there are cases of aneurysms diagnosed incidentally on radiology reporting but lost to follow-up.

METHODS

Clinical Portal (CP) is a widely used patient-centred dashboard for viewing health information that is managed by Orion Health. A search strategy utilising the CP common database was devised that aimed to find aneurysms which were not followed up. This search was performed retrospectively for all imaging within a 5-month period.

RESULTS

Some 294 scans were flagged and 53 patients with aneurysms were found. Of these patients, 36 had follow-up by the ordering provider and 17 (32%) were found to have been lost to follow-up.

CONCLUSIONS

Our pilot study demonstrated high rates of loss to follow-up and a lack of communication of important health information across multiple health disciplines in the region, and represents a potential method for identifying 'lost' aneurysms. For patients in rural communities, this may be critical to preventing future complications from aneurysmal disease.

The Impact of Suprarenal Diameter on Outcomes Following Endovascular Aneurysm Repair: A Retrospective Cohort Study

OBJECTIVES

To determine the association between suprarenal aortic diameters and complications that may be attributed to a dilating phenotype following endovascular abdominal aortic aneurysm repair.

DESIGN

This study is a retrospective review.

METHODS

We measured the abdominal aortas of 147 consecutive patients with a mean age of 78.5 (range 60-93) years, who had a mean Endovascular aneurysm repair (EVAR) follow-up of 3 years (6 months to 8 years) at a public Hospital. Aortic calibres measured 5 mm above the highest renal artery were recorded, patients were categorised according to suprarenal diameter; Group A: greater than 25 mm, Group B: less than or equal to 25 mm. Stent migration, aneurysmal sac growth, presence of an endoleak and its type, occlusion events, rupture, interventions and mortality, as well as clinical history and demographic data were compared between groups.

RESULTS

There was a significantly higher occurrence of stent migration (11% v 0%; P = .01) in patients with larger suprarenal aortas (Group A). The occurrence of any endoleak did not differ between the groups, however, significantly more complications resulting in secondary intervention, excluding occlusions, were noted in Group A (34% vs 17%, P = .04).

CONCLUSIONS

The results from this study suggest that patients with above-average suprarenal diameters (categorised as dilators) may have a higher occurrence of specific complications following EVAR. A more detailed study to establish the association of suprarenal calibre with types of complications following EVAR is warranted.

The Impact of Abdominal Aortic Aneurysm on Cardiovascular Diseases

Cardiovascular diseases (CVDs) including myocardial infarction (MI) and stroke are often diagnosed in patients with abdominal aortic aneurysm (AAA). However, little has been reported regarding the incidence.Patients with AAA were selected from the National Health Insurance system in South Korea between 2009 and 2015. A total of 10,822 participants with a new diagnosis of AAA were included. Propensity score matching by age and sex with patients in whom AAA was not diagnosed was used to select the control group of 32,466 participants. Primary endpoints included the diagnosis of CVD and death. Cox proportional hazard models were used to compare the risk of disease incidence.The incidence of CVD was 16.573 per 1,000 person-years in the AAA group, which was higher than that of the control group's 9.30 per 1,000 person-years. The incidence of MI (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.479-1.953), stroke (HR, 1.629; 95% CI, 1.443-1.839), and CVD (HR, 1.672; 95% CI, 1.522-1.835) was significantly higher in patients with AAA. Mortality rate was also elevated in the AAA group (HR, 2.544; 95% CI, 2.377-2.722).The incidence of CVD was significantly more frequent in patients with AAA. The AAA group had consistently higher risks regarding CVD and mortality than the control group.

Ultrasound screening for abdominal aortic aneurysm in high-risk women

Background

Population-wide ultrasound screening programmes for abdominal aortic aneurysm (AAA) for men have already been established in some countries. Women account for one third of aneurysm-related mortality and are four times more likely to experience an AAA rupture than men. Whole-population screening for AAA in women is unlikely to be clinically or economically effective. The aim of this study was to determine the outcomes of a targeted AAA screening programme for women at high risk of AAA.

Method

Women aged 65–74 years deemed at high risk of having an AAA (current smokers, ex-smokers, or with a history of coronary artery disease) were invited to attend ultrasound screening (July 2016 to March 2019) for AAA in the Female Aneurysm screening STudy (FAST). Primary outcomes were attendance for screening and prevalence of AAA. Biometric data, medical history, quality of life (QoL) and aortic diameter on ultrasound imaging were recorded prospectively.

Results

Some 6037 women were invited and 5200 attended screening (86.7 per cent). Fifteen AAAs larger than 29 mm were detected (prevalence 0.29 (95 per cent c.i. 0.18 to 0.48) per cent). Current smokers had the highest prevalence (0.83 (95 per cent c.i. 0.34 to 1.89) per cent) but lowest attendance (75.2 per cent). Three AAAs greater than 5.5 cm were identified and referred for consideration of surgical repair; one woman underwent repair. There was a significant reduction in patient-reported QoL scores following screening.

Conclusion

A low prevalence of AAA was detected in high-risk women, with lowest screening uptake in those at highest risk. Screening for AAA in high-risk women may not be beneficial.

Feasibility and Efficiency Study of a Population-Based Abdominal Aortic Aneurysm Screening Program in Men and Women in Spain

BACKGROUND

Based on current evidence, one-time screening for abdominal aortic aneurysm (AAA) in men using ultrasound evaluation reduces mortality related to AAA rupture and is considered cost-effective, although all-cause mortality reduction still remains in question. In Spain, there is no population screening program for AAA, so the aim of our study was to perform a pilot population screening program in our area to assess feasibility and efficiency of an AAA screening program for men and women.

METHODS

A population AAA screening pilot program was performed in a Barcelona area, including 400,000 inhabitants. According to inclusion criteria, 4,730 individuals aged 65 years at the moment of the trial were invited for screening (2,089 men and 2,641 women). Primary care doctors, trained in duplex ultrasound abdominal evaluations, performed an abdominal aortic measurement. Individuals with a previous diagnosis of AAA, limited life expectancy, or wrong contact data were excluded. Participation data, aortic diameters, AAA prevalence, and related cardiovascular risk factors were analyzed. The results were used in a cost-utility model to assess the efficiency of the screening program.

RESULTS

Participation was 50.3% in men and 44% in women. Eleven patients were excluded because of previously diagnosed AAA. Five new asymptomatic AAA were detected in 65-year-old men (0.5% prevalence), all being active smokers. When considering patients excluded for previous AAA diagnosis, the prevalence in 65-year-old men reached 1.4%. Global AAA prevalence in smoking men reached 2.67%. No AAA was detected in women. Subaneurysmal aorta prevalence in men was 2.9% (n = 29), and in women, it was 0.08% (n = 2). A cost-utility analysis model on screening versus no screening retrieved 13,664€ per quality-adjusted life years at a 10-year horizon and 39,455€ per quality-adjusted life years at a 30-year horizon.

CONCLUSIONS

AAA population-based screening by ultrasound evaluation in primary care is logistically feasible in our area. Despite that, AAA prevalence is lower than expected in men, and null in women. Cost-utility model results indicate that a local AAA screening program is only efficient in a 30 years' time horizon. Such inefficient results for a population screening make it necessary to consider other strategies such as opportunistic or subgroup screening in our area.

Screening for abdominal aortic aneurysm in patients with clinically manifest vascular disease

AIMS

Declining prevalence of abdominal aortic aneurysm (AAA) might force a more targeted screening approach (high-risk populations only) in order to maintain (cost-)effectiveness. We aimed to determine temporal changes in the prevalence of screening-detected AAA, to assess AAA-related surgery, and evaluate all-cause mortality in patients with manifest vascular disease.

METHODS AND RESULTS

We included patients with manifest vascular disease but without a history of AAA enrolled in the ongoing single-centre prospective UCC-SMART cohort study. Patients were screened at baseline for AAA by abdominal ultrasonography. We calculated sex- and age-specific prevalence of AAA, probability of survival in relation to the presence of AAA, and the proportion of patients undergoing AAA-related surgery. Prevalence of screening-detected AAA in 5440 screened men was 2.5% [95% confidence interval (CI) 2.1-2.9%] and in 1983 screened women 0.7% (95% CI 0.4-1.1%). Prevalence declined from 1997 until 2017 in men aged 70-79 years from 8.1% to 3.2% and in men aged 60-69 years from 5.7% to 1.0%. 36% of patients with screening-detected AAA received elective AAA-related surgery during follow-up (median time until surgery = 5.3 years, interquartile range 2.5-9.1). Patients with screening-detected AAA had a lower probability of survival (sex and age adjusted) compared to patients without screening-detected AAA (51%, 95% CI 41-64% vs. 69%, 95% CI 68-71%) after 15 years of follow-up.

CONCLUSION

The prevalence of screening-detected AAA has declined over the period 1997-2017 in men with vascular disease but exceeds prevalence in already established screening programs targeting 65-year-old men. Screening for AAA in patients with vascular disease may be cost-effective, but this remains to be determined.

Genetic and Epigenetic Mechanisms Underlying Vascular Smooth Muscle Cell Phenotypic Modulation in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) refers to the localized dilatation of the infra-renal aorta, in which the diameter exceeds 3.0 cm. Loss of vascular smooth muscle cells, degradation of the extracellular matrix (ECM), vascular inflammation, and oxidative stress are hallmarks of AAA pathogenesis and contribute to the progressive thinning of the media and adventitia of the aortic wall. With increasing AAA diameter, and left untreated, aortic rupture ensues with high mortality. Collective evidence of recent genetic and epigenetic studies has shown that phenotypic modulation of smooth muscle cells (SMCs) towards dedifferentiation and proliferative state, which associate with the ECM remodeling of the vascular wall and accompanied with increased cell senescence and inflammation, is seen in in vitro and in vivo models of the disease. This review critically analyses existing publications on the genetic and epigenetic mechanisms implicated in the complex role of SMCs within the aortic wall in AAA formation and reflects the importance of SMCs plasticity in AAA formation. Although evidence from the wide variety of mouse models is convincing, how this knowledge is applied to human biology needs to be addressed urgently leveraging modern in vitro and in vivo experimental technology.

Both Small and Large Infrarenal Aortic Size is Associated with an Increased Prevalence of Ischaemic Heart Disease

OBJECTIVE

Past studies have suggested a potential "J shaped" relationship between infrarenal aortic diameter and both cardiovascular disease (CVD) prevalence and all cause mortality. However, screening programmes have focused primarily on large (aneurysmal) aortas. In addition, aortic diameter is rarely adjusted for body size, which is particularly important for women. This study aimed to investigate specifically the relationship between body size adjusted infrarenal aortic diameter and baseline prevalence of CVD.

METHODS

A retrospective analysis was performed on a total of 4882 elderly (>50 years) participants (mean age 69.4 ± 8.9 years) for whom duplex ultrasound to assess infrarenal abdominal aortic diameters had been performed. History of CVDs, including ischaemic heart disease (IHD), and associated risk factors were collected at the time of assessment. A derivation cohort of 1668 participants was used to select cut offs at the lower and upper 12.5% tails of the aortic size distributions (aortic size index of <0.84 and >1.2, respectively), which was then tested in a separate cohort.

RESULTS

A significantly elevated prevalence of CVD, and specifically IHD, was observed in participants with both small and large aortas. These associations remained significant following adjustment for age, sex, diabetes, hypertension, dyslipidaemia, obesity (body mass index), and smoking.

CONCLUSION

The largest and smallest infrarenal aortic sizes were both associated with prevalence of IHD. In addition to identifying those with aneurysmal disease, it is hypothesised that screening programmes examining infrarenal aortic size may also have the potential to improve global CVD risk prediction by identifying those with small aortas.

DNA methylation profiling identifies a high effect genetic variant for lipoprotein(a) levels

Changes in whole blood DNA methylation levels at several CpG sites have been associated with circulating blood lipids, specifically high-density lipoprotein and triglycerides. This study performs a discovery and validation epigenome-wide association study (EWAS) for circulating lipoprotein(a) [Lp(a)], an independent risk factor for cardiovascular diseases. Whole-blood DNA methylation profiles were assessed in a cohort of 1020 elderly individuals using the Illumina EPIC array and independent validation in 359 elderly males using the Illumina 450 k array. Plasma Lp(a) was measured using an apolipoprotein(a)-size-independent ELISA. Epigenome-wide rank regression analysis identified and validated a single CpG site, cg17028067 located in intron 1 of the LPA gene, that was significantly associated with plasma Lp(a) levels after correction for multiple testing. Genotyping of the site identified a relatively uncommon SNP (rs76735376, MAF <0.02) at the CpG site that largely explained the observed methylation effect. Rs76735376 is an expression quantitative trait loci for the LPA gene and could affect expression by altering enhancer activity. This EWAS for plasma Lp(a) identified a single CpG site within LPA. This association is due to an uncommon, but highly effective genetic variant, which was not in significant linkage disequilibrium with other variants known to influence Lp(a) levels or apo(a) isoform size. This study highlights the utility of CpG site methylation to identify potentially important genetic associations that would not be readily apparent in a comparable size genetic association study.

Genetics of Thoracic and Abdominal Aortic Diseases

Dissections or ruptures of aortic aneurysms remain a leading cause of death in the developed world, with the majority of deaths being preventable if individuals at risk are identified and properly managed. Genetic variants predispose individuals to these aortic diseases. In the case of thoracic aortic aneurysm and dissections (thoracic aortic disease), genetic data can be used to identify some at-risk individuals and dictate management of the associated vascular disease. For abdominal aortic aneurysms, genetic associations have been identified, which provide insight on the molecular pathogenesis but cannot be used clinically yet to identify individuals at risk for abdominal aortic aneurysms. This compendium will discuss our current understanding of the genetic basis of thoracic aortic disease and abdominal aortic aneurysm disease. Although both diseases share several pathogenic similarities, including proteolytic elastic tissue degeneration and smooth muscle dysfunction, they also have several distinct differences, including population prevalence and modes of inheritance.

Prevalence of abdominal aortic aneurysm and associated lower extremity artery aneurysm in men hospitalized for suspected or known cardiopulmonary disease

BACKGROUND

AAA is a disease affecting predominantly male patients ≥65 years and its dreaded complications such as rupture led to population-based screening programs as preventive measure. Nonetheless, the supposed prevalence may have been overestimated, so that targeted screening of high risk populations may be more effective. This study was performed to evaluate the prevalence of abdominal aortic aneurysm (AAA) of an inpatient high-risk cohort and to estimate the co-prevalence of lower extremity arterial aneurysms.

METHODS

Participants: 566 male inpatients, ≥ 65 years of age, hospitalized for suspected or known cardiopulmonary disease. Primary and secondary outcome measures: Maximal infrarenal aortic diameters using abdominal ultrasound (leading edge to leading edge method). Upon detection of an AAA (diameter ≥ 30 mm), the lower extremity arteries were examined with regard to associated aneurysms.

RESULTS

In 40 of 566 patients (7.1%) AAAs were detectable. Fourteen patients (2.5%) had a first diagnosis of AAA, none of which was large (> 55 mm), the remaining 26 patients were either already diagnosed (14 patients, 2.5%) or previously repaired (12 patients, 2.1%). The three most common main diagnoses at discharge were acute coronary syndrome (43.3%), congestive heart failure (32.2%), and chronic obstructive pulmonary disease (12%). The cohort showed a distinct cardiovascular risk profile comprising arterial hypertension (82.9%), diabetes mellitus (44.4%), and a history of smoking (57.6%). In multivariate analysis, three-vessel coronary artery disease (Odds ratio (OR): 4.5, 95% confidence interval (CI): 2.3-8.9, p <  0.0001) and history of smoking (OR: 3.7, CI: 1.6-8.6, p <  0.01) were positively associated with AAA, while diabetes mellitus (OR: 0.5, CI: 0.2-0.9, p = 0.0295) showed a negative association with AAA. Among the subjects with AAA, we found two large iliac and two large popliteal aneurysms.

CONCLUSION

Ultrasound screening in male inpatients, hospitalized for suspected or known cardiopulmonary disease, revealed a high AAA prevalence in comparison to the present epidemiological screening programs. There was a moderate proportion of newly-screen detected AAA and additional screening of the lower extremity arteries yielded some associated aneurysms with indication for possible intervention.

A variant of the castor zinc finger 1 (CASZ1) gene is differentially associated with the clinical classification of chronic venous disease

Recent reports have suggested a reproducible association between the rs11121615 SNP, located within an intron of the castor zinc finger 1 (CASZ1) gene, and varicose veins. This study aimed to determine if this variant is also differentially associated with the various clinical classifications of chronic venous disease (CVD). The rs11121615 SNP was genotyped in two independent cohorts from New Zealand (n = 1876 controls /1606 CVD cases) and the Netherlands (n = 1626/2966). Participants were clinically assessed using well-established CVD criteria. The association between the rs11121615 C-allele and varicose veins was validated in both cohorts. This was strongest in those with higher clinical severity classes and was not significant in those with non-varicose vein CVD. Functional analysis of the rs11121615 variant demonstrated that the risk allele was associated with increased enhancer activity. This study demonstrates that the CASZ1 gene associated C-allele of rs11121615 has a significant, reproducible, association with CVD (CEAP C ≥ 2 meta-odds ratio 1.31, 95% CI 1.27–1.34, P = 1 × 10⁻⁹⁸, PHet = 0.25), but not with non-varicose vein (CEAP C1, telangiectasia or reticular veins) forms of venous disease. The effect size of this association therefore appears to be susceptible to influence by phenotypic heterogeneity, particularly if a cohort includes a large number of cases with lower severity CVD.

Health gains, costs and cost-effectiveness of a population-based screening programme for abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) rupture carries a high fatality rate. AAAs can be detected before rupture by abdominal ultrasound imaging, allowing elective repair. Population-based screening for AAA in older men reduces AAA-related mortality by about 40 per cent. The UK began an AAA screening programme offering one-off scans to men aged 65 years in 2009. Sweden has a similar programme. Currently, there is no AAA screening programme in New Zealand. This cost-utility analysis aimed to assess the cost-effectiveness of a UK-style screening programme in the New Zealand setting.

METHODS

The analysis compared a formal AAA screening programme (one-off abdominal ultrasound imaging for about 20 000 men aged 65 years in 2011) with no systematic screening. A Markov macrosimulation model was adapted to estimate the health gains (in quality-adjusted life-years, QALYs), health system costs and cost-effectiveness in New Zealand. A health system perspective and lifetime horizon was adopted.

RESULTS

With New Zealand-specific inputs, the adapted model produced an estimate of about NZ $15 300 (€7746) per QALY gained, with a 95 per cent uncertainty interval (UI) of NZ $8700 to 31 000 (€4405 to 15 694) per QALY gained. Health gains were estimated at 117 (95 per cent UI 53 to 212) QALYs. Health system costs were NZ $1·68 million (€850 535), with a 95 per cent UI of NZ $820 200 to 3·24 million (€415 243 to €1·65 million).

CONCLUSION

Using New Zealand's gross domestic product per capita (about NZ $45 000 or €22 100) as a cost-effectiveness threshold, a UK-style AAA screening programme would be cost-effective in New Zealand.

Correcting for Body Surface Area Identifies the True Prevalence of Abdominal Aortic Aneurysm in Screened Women

OBJECTIVE

Recently, the prevalence of abdominal aortic aneurysm (AAA) using screening strategies based on elevated cardiovascular disease (CVD) risk was reported. AAA was defined as a diameter ≥30 mm, with prevalence of 6.1% and 1.8% in men and women respectively, consistent with the widely reported AAA predominant prevalence in males. Given the obvious differences in body size between sexes this study aimed to re-evaluate the expanded CVD risk based AAA screening dataset to determine the effect of body size on sex specific AAA prevalence.

METHODS

Absolute (26 and 30 mm) and relative (aortic size index [ASI] equals the maximum infrarenal aorta diameter (cm) divided by body surface area (m²), ASI ≥ 1.5) thresholds were used to assess targeted AAA screening groups (n = 4115) and compared with a self reported healthy elderly control group (n = 800).

RESULTS

Male AAA prevalence was the same using either the 30 mm or ASI ≥1.5 aneurysm definitions (5.7%). In females, AAA prevalence was significantly different between the 30 mm (2.4%) and ASI ≥ 1.5 (4.5%) or the 26 mm (4.4%) thresholds.

CONCLUSION

The results suggest the purported male predominance in AAA prevalence is primarily an artefact of body size differences. When aortic size is adjusted for body surface area there is only a modest sex difference in AAA prevalence. This observation has potential implications in the context of the ongoing discussion regarding AAA screening in women.

A registry-based rationale for discrete intervention thresholds for open and endovascular elective abdominal aortic aneurysm repair in female patients

OBJECTIVE

An evidence-based consensus for a female-specific intervention threshold for abdominal aortic aneurysms (AAAs) is missing. This study aims to analyze sex-related differences in the epidemiology of ruptured AAA to establish an intervention threshold for women.

METHODS

The Dutch Surgical Aneurysm Audit (DSAA) is a compulsory, nation-wide registry of AAA repairs in The Netherlands. All patients with emergency or elective AAA repair between January 1, 2013, and December 31, 2015, were included in the analysis. The main outcomes were age, sex, AAA diameter at time of rupture, and 30-day postoperative mortality.

RESULTS

A total of 1561 ruptured AAA repairs (14.7% women) and 7063 cases of elective AAA repair (13.7% women) were included in the analysis. Women had significantly smaller mean ± standard deviation AAA diameter at time of rupture than men; 70.5 ± 14.4 mm and 78.6 ± 17.5 mm, respectively. In male patients, 8% of ruptures occurred at diameters below the 55 mm intervention threshold. The female equivalent of this eighth percentile is 52 mm. Female patients had significantly higher 30-day mortality after emergency repair, namely, 33% for women versus 24.2% for men, but were also significantly older, mean ± standard deviation age 76.7 ± 7.1 years and 73.9 ± 8.3 years for women and men, respectively. Correcting for age reduced the 30-day mortality risk for women after ruptured AAA repair from 1.53 (95% confidence interval, 1.14-2.04) to 1.27 (95% confidence interval, 0.92-1.73). Outcome after open elective repair was significantly worse for women compared with men, with a 30-day mortality of 7.97% 30 for women and 4.27% for men (P < .01).

CONCLUSIONS

The equivalent of the 55-mm intervention threshold for elective endovascular AAA repair in men is 52 mm in women. The almost doubled mortality risk for elective open repair in women implies that the optimal point for open repair is at higher diameters, very possibly at least 55 mm.

High serum thrombospondin-1 concentration is associated with slower abdominal aortic aneurysm growth and deficiency of thrombospondin-1 promotes angiotensin II induced aortic aneurysm in mice

Abdominal aortic aneurysm (AAA) is a common age-related vascular disease characterized by progressive weakening and dilatation of the aortic wall. Thrombospondin-1 (TSP-1; gene Thbs1) is a member of the matricellular protein family important in the control of extracellular matrix (ECM) remodelling. In the present study, the association of serum TSP-1 concentration with AAA progression was assessed in 276 men that underwent repeated ultrasound for a median 5.5 years. AAA growth was negatively correlated with serum TSP-1 concentration (Spearman's rho -0.129, P=0.033). Men with TSP-1 in the highest quartile had a reduced likelihood of AAA growth greater than median during follow-up (OR: 0.40; 95% confidence interval (CI): 0.19-0.84, P=0.016, adjusted for other risk factors). Immunohistochemical staining for TSP-1 was reduced in AAA body tissues compared with the relatively normal AAA neck. To further assess the role of TSP-1 in AAA initiation and progression, combined TSP-1 and apolipoprotein deficient (Thbs1-/-ApoE-/-, n=20) and control mice (ApoE-/-, n=20) were infused subcutaneously with angiotensin II (AngII) for 28 days. Following AngII infusion, Thbs1-/- ApoE-/- mice had larger AAAs by ultrasound (P=0.024) and ex vivo morphometry measurement (P=0.006). The Thbs1-/-ApoE-/- mice also showed increased elastin filament degradation along with elevated systemic levels and aortic expression of matrix metalloproteinase (MMP)-9. Suprarenal aortic segments and vascular smooth muscle cells (VSMCs) isolated from Thbs1-/-ApoE-/- mice showed reduced collagen 3A1 gene expression. Furthermore, Thbs1-/-ApoE-/- mice had reduced aortic expression of low-density lipoprotein (LDL) receptor-related protein 1. Collectively, findings from the present study suggest that TSP-1 deficiency promotes maladaptive remodelling of the ECM leading to accelerated AAA progression.

Identification of the main determinants of abdominal aorta size: a screening by Pocket Size Imaging Device

Background

Ultrasound exam as a screening test for abdominal aorta (AA) can visualize the aorta in 99% of patients and has a sensitivity and specificity approaching 100% in screening settings for aortic aneurysm. Pocket Size Imaging Device (PSID) has a potential value as a screening tool, because of its possible use in several clinical settings. Our aim was to assess the impact of demographics and cardiovascular (CV) risk factors on AA size by using PSID in an outpatient screening.

Methods

Consecutive patients, referring for a CV assessment in a 6 months period, were screened. AA was visualized by subcostal view in longitudinal and transverse plans in order to determine the greatest anterior-posterior diameter. After excluding 5 patients with AA aneurysm, 508 outpatients were enrolled. All patients underwent a sequential assessment including clinical history with collection of CV risk factors, physical examination, PSID exam and standard Doppler echoc exam using a 2.5 transducer with harmonic capability, both by expert ultrasound operators, during the same morning. Standard echocardiography operators were blinded on PSID exam and viceversa.

Results

Diagnostic accuracy of AA size by PSID was tested successfully with standard echo machine in a subgroup (n = 102) (rho = 0.966, p < 0.0001). AA diameter was larger in men than in women and in ≥50 -years old subjects than in those <50 -years old (both p < 0.0001). AA was larger in patients with coronary artery disease (CAD) (p < 0.0001). By a multivariate model, male sex (p < 0.0001), age and body mass index (both p < 0.0001), CAD (p < 0.01) and heart rate (p = 0.018) were independent predictors of AA size (cumulative R² = 0.184, p < 0.0001).

Conclusion

PSID is a reliable tool for the screening of determinants of AA size. AA diameter is greater in men and strongly influenced by aging and overweight. CAD may be also associated to increased AA diameter.

Prevalence of abdominal aortic aneurysms and its relation with cardiovascular risk stratification: protocol of the Risk of Cardiovascular diseases and abdominal aortic Aneurysm in Varese (RoCAV) population based study

BACKGROUND

Recent meta-analyses suggested that screening program for abdominal aortic aneurysms (AAA) in 65-year old males is cost-effective at prevalence of about 1%. Since some events occur also in females and among the youngers, screening could be feasible among those at higher risk, such as smokers or individuals with a family history of AAA. The RoCAV (Risk of Cardiovascular diseases and abdominal aortic Aneurysms in Varese) Project is a population-based study aimed to evaluate AAA prevalence in Northern Italy in males over-65 years as well as among females and younger males, and to identify new markers for risk stratification by collecting a large set of CVD risk factors. The aims of the project are: (i) cross-sectional evaluation of AAA prevalence (ii); evaluation of standard CVD risk score as criteria for selecting subgroup at higher risk to be included in a screening program; (iii) identification of new risk markers and risk score algorithm for AAA and CVD risk stratification; (iv) cost-effective evaluation during the follow-up.

METHODS

Males aged 50-75 years and females aged 60-75 years, resident in the city of Varese (Lombardy Region), were randomly selected from the civil registry. Among 5198 successfully invited, 3777 subjects accepted to participate and were finally recruited (participation rate 63.8%) from June 2013 to May 2016. Trained operators administered a computerized anamnestic questionnaire, measured anthropometric parameters (BMI, body circumferences, skinfolds), blood pressure, ankle-brachial index, pulse wave velocity and performed abdominal aortic ultrasound scan, ECG and spirometry. All methods were internationally validated. A blood sample was collected and stored in biobank. A follow-up will be carried out through linkage with electronic records.

DISCUSSION

Participation rate and data quality assessment were as expected and will reasonably allow to reach the project aims. The expected impact in public health of the RoCAV project will be the potential implementation of a AAA screening program to the whole region as well as the formulation of new criteria for risk assessment of AAA and CVD.