What is the role of screening in the management of abdominal aortic aneurysms?

Editor's Choice - Infra-Renal Aortic Diameter and Cardiovascular Risk: Making Better Use of Abdominal Aortic Aneurysm Screening Outcomes

OBJECTIVE

Aortic diameter (AD), used traditionally for abdominal aortic aneurysm (AAA) screening may have a role in assessing cardiovascular risk. Unfortunately, AD estimates for those without AAA are underutilised, whilst cardiovascular risk is sub-optimally managed in those with AAA. Our objective was to examine the association between AD measurements and future cardiovascular risk.

METHODS

Retrospective analysis of three databases of male participants screened for aortic aneurysm disease. Imaging and clinical data were obtained from three independent sources: 1) the Multi-centre Aneurysm Screening Study (MASS) trial (n = 26 882 men); 2) the 2013/14 cohort of the English NHS AAA Screening Programme (NAAASP) (n = 237 441 men) linked with NHS hospital admission and death registry data; and 3) the Framingham Heart Study (FHS) offspring cohort (n = 649). Associations between maximal aortic diameter, as measured on ultrasound or computed tomography, and cardiovascular outcomes were examined.

RESULTS

Cardiovascular mortality in the MASS trial, was higher in men with AAA at 13 years of follow up, compared to those without (Hazard Ratio [HR] 2.22, 95% CI 1.97-2.50, p < .001). Contemporary risk of major adverse cardiovascular events in the NAAASP was highest in those with an AAA (HR 2.91, 95% CI 2.00-4.25), whilst, extremes of aortic diameter were associated with increased risk for cardiovascular events. Aortic diameter was an independent risk factor for cardiovascular events in the FHS dataset.

CONCLUSION

Irrespective of the diagnosis of AAA, men attending for AAA screening who are found to have an abnormal aortic diameter are at high risk of future cardiovascular events. This currently unutilised data from AAA screening programmes has the potential to improve preventative management of cardiovascular risk.

Identification of a Plasma Microrna Signature as Biomarker of Subaneurysmal Aortic Dilation in Patients with High Cardiovascular Risk

Patients with subaneurysmal aortic dilation (SAD; 25–29 mm diameter) are likely to progress to true abdominal aortic aneurysm (AAA). Despite these patients having a higher risk of all-cause mortality than subjects with aortic size <24 mm, early diagnostic biomarkers are lacking. MicroRNAs (miRs) are well-recognized potential biomarkers due to their differential expression in different tissues and their stability in blood. We have investigated whether a plasma miRs profile could identify the presence of SAD in high cardiovascular risk patients. Using qRT-PCR arrays in plasma samples, we determined miRs differentially expressed between SAD patients and patients with normal aortic diameter. We then selected 12 miRs to be investigated as biomarkers by construction of ROC curves. A total of 82 significantly differentially expressed miRs were found by qPCR array, and 12 were validated by qRT-PCR. ROC curve analyses showed that seven selected miRs (miR-28-3p, miR-29a-3p, miR-93-3p, miR-150-5p, miR-338-3p, miR-339-3p, and miR-378a-3p) could be valuable biomarkers for distinguishing SAD patients. MiR-339-3p showed the best sensitivity and specificity, even after combination with other miRs. Decreased miR-339-3p expression was associated with increased aortic abdominal diameter. MiR-339-3p, alone or in combination with other miRs, could be used for SAD screening in high cardiovascular risk patients, helping to the early diagnosis of asymptomatic AAA.

[Choosing wisely together with the patient]

Within the framework of the Choosing wisely initiative of the German Society for Internal Medicine, all scientific societies associated with internal medicine were requested to highlight the unnecessary or underused medical tests or procedures out of the 60 defined examples, which are of immediate relevance within the doctor-patient interaction. Each of the 12 scientific internal medicine societies compiled and substantiated 2 recommendations. This resulted in a spectrum of important recommendations covering the entire field of internal medicine. In difficult situations these recommendations should contribute to developing and supporting the dialogue with patients on an evidence-based level.

Screening results from a large United Kingdom abdominal aortic aneurysm screening center in the context of optimizing United Kingdom National Abdominal Aortic Aneurysm Screening Programme protocols

BACKGROUND

After its introduction in six pilot centers in 2009, the National Abdominal Aortic Aneurysm Screening Programme (NAAASP) is now established across the United Kingdom, demonstrating significant benefit in terms of fewer emergency surgeries and reduced 30-day surgical mortality. However, according to publication of data on annual screened abdominal aortic aneurysm (AAA) detection, a lower incidence than predicted in the original screening trials has been found. In this audit we assessed features and risk factors of men found to have a positive scan result in the southwest London AAA screening program, to determine screening yield for subgroups of populations and assess the case for a more targeted screening program.

METHODS

Data from the NAAASP screening database for England were extracted for all men who attended screening from the April 1, 2009 through October 16, 2013 in the southwest London area. Primary outcomes were aneurysm prevalence, risk factors, and incidence within subgroups. Results were reviewed against nationally reported data and London census data.

RESULTS

Of 24,891 men who were screened in the southwest London program during this period, 292 AAAs were identified (1.18%). Patients were asked to categorize their ethnic background according to classifications provided by the office of national statistics. Those at highest risk of AAA were white-British (1.35%), followed by black and black British (0.65%), and Asian/Asian British (0.23%). Number needed to screen to identify one AAA was calculated as 78, 154, and 431, respectively. The relative proportions of patients screened were similar to that described in the most recent United Kingdom census, except for white-British patients, indicating a shortfall in acceptance of screening invitations in this group. There were no AAA identified in Chinese men. A positive smoking history was found in 90%, a confirmed diagnosis of hypertension in 50%, hypercholesterolemia in 34%, and ischemic heart disease in 21%.

CONCLUSIONS

Within southwest London, AAA was most strongly associated with being white-British, a previous or current smoker, and known hypertension. Targeted education in patient groups with identified risk factors for AAA should be considered to improve screening yield without excluding any subgroup from the screening program. This could draw on resources released by unused scans because of lower than predicted prevalence. AAA diagnosis should be seen as an opportunity to address the increased all-cause mortality associated with aortic aneurysmal disease.

Screening of COPD patients for abdominal aortic aneurysm

Purpose

Screening for abdominal aortic aneurysm (AAA) in “men aged over 65 years who have ever smoked” is a recommended policy. To reduce the number of screenings, it may be of value to define subgroups with a higher prevalence of AAA. Since chronic obstructive pulmonary disease (COPD) and AAA are associated with several common risk factors, this study investigates the prevalence of AAA in COPD patients.

Patients and methods

Patients with COPD were identified via the hospital information system. Inclusion criteria were: COPD stage I–IV, ability to give full consent, and age >18 years; exclusion criteria were: patient too obese for an ultrasound check, previously diagnosed AAA, prior surgery for AAA, or ethical grounds such as concomitant advanced malignant or end-stage disease. The primary endpoint of the study was an aortic diameter measured by ultrasound of ≥30 mm. Defined secondary endpoints were evaluated on the basis of medical records and interviews.

Results

Of the 1,180 identified COPD patients, 589 were included in this prospective study. In 22 patients (3.70%), the aortic diameter was ≥30 mm, representing an AAA prevalence of 6.72% among males aged >65 years. The risk of AAA increased with the following comorbidities/risk factors: male sex (odds ratio [OR] 2.98), coronary heart disease (OR 2.81), peripheral arterial occlusive disease (OR 2.47), hyperlipoproteinemia (OR 2.77), AAA in the family history (OR 3.95), and COPD stage I/II versus IV (OR 1.81).

Conclusion

The overall AAA prevalence of 3.7% in our group of COPD patients is similar to that of the general population aged >65 years. However, the frequency of AAA in male COPD patients aged >65 years is considerably higher (6.72%) and increased further still in those individuals with additional comorbidities/risk factors. Defining subgroups with a higher risk of AAA may increase the efficiency of screening.

Influence of rurality, deprivation and distance from clinic on uptake in men invited for abdominal aortic aneurysm screening

BACKGROUND

Effective abdominal aortic aneurysm (AAA) screening requires high uptake. The aim was to assess the independent association of screening uptake with rurality, social deprivation, clinic type, distance to clinic and season.

METHODS

Screening across Grampian was undertaken by trained nurses in six community and three hospital clinics. Men aged 65 years were invited for screening by post (with 2 further reminders for non-responders). AAA screening data are stored on a national call-recall database. The Scottish postcode directory was used to allocate to all invited men a deprivation index (Scottish Index of Multiple Deprivation), a Scottish urban/rural category and distance to clinic. Multivariable analysis was undertaken.

RESULTS

The cohort included 5645 men invited for screening over 12 months (October 2012 to October 2013); 42·6 per cent lived in urban areas, 38·9 per cent in rural areas and 18·5 per cent in small towns (uptake 87·0, 89·3 and 90·8 per cent respectively). Overall uptake was 88·6 per cent with 76 new AAAs detected: 15·2 (95 per cent c.i. 11·8 to 18·6) per 1000 men screened. Aberdeen city (large urban area) had the lowest uptake (86·1 per cent). Uptake declined with increasing deprivation, with the steepest decline in urban areas. On multivariable analysis, a 1-point increase in deprivation deciles was associated with a 0·08 (95 per cent c.i. 0·06 to 0·11) reduction in the odds of being screened (P < 0·001). Clinic type (community versus hospital), distance to clinic and season were not associated independently with uptake.

CONCLUSION

Both urban residence and social deprivation were associated independently with uptake among men invited for AAA screening.