The Low Prevalence of Abdominal Aortic Aneurysm in Relatives in Northern Ireland

Whole aorta imaging shows increased risk for thoracic aortic aneurysms and dilatations in relatives of abdominal aortic aneurysm patients

OBJECTIVE

For relatives of abdominal aortic aneurysm (AAA) patients, guidelines recommend abdominal imaging aimed at early detection and management of AAA, and do not include screening for thoracic aortic aneurysms (TAA). We aimed to investigate if TAA occur in undiagnosed relatives of patients with AAA without a known genetic susceptibility for aneurysms, similar to families with identified genetic susceptibilities for aneurysms like in Marfan and Loeys-Dietz syndrome, where both AAAs and TAAs occur.

METHODS

Relatives of patients with AAA were invited for noncontrast whole aorta computed tomography (CT) screening. Systematic measurements of the CT scans were used to detect aneurysms and dilatations. Classification into familial and nonfamilial was based on reported family histories. In addition, aneurysm gene panel testing of AAA index cases was used for the classification of high vs unknown genetic risk (high genetic risk: familial aneurysm or a pathogenic/likely pathogenic (P/LP) in an aneurysm gene; unknown genetic risk: no family history or P/LP).

RESULTS

Whole aorta imaging of 301 relatives of 115 index patients with AAA with noncontrast CT scans showed a 28-fold increase in TAAs in relatives (1.7% [P < .001] vs the age-adjusted population) and a high frequency of thoracic dilatations in 18% of the relatives. Thoracic aneurysms and dilatations in relatives occurred even when index patients were unaware of familial aneurysms. AAA was increased in the relatives compared with the age-adjusted population (8%; P < .001).

CONCLUSIONS

An increased risk for thoracic aneurysms and dilatations was detected by whole aorta imaging of relatives of index patients with AAA, even when index patients were unaware of familial aneurysms. These results indicate still unknown, shared genetic susceptibilities for thoracic and abdominal aneurysms. Therefore, imaging of the whole aorta of relatives of all abdominal aneurysm patients, will improve early detection of aortic aneurysms in relatives of all patients with AAA.

Outcomes of familial abdominal aortic aneurysm repair in the Vascular Quality Initiative

OBJECTIVE

Recent investigations have reported increased rates of aneurysm-related complications after endovascular aneurysm repair (EVAR) in familial abdominal aortic aneurysm (fAAA) patients. The purpose of this study was to evaluate the outcomes of open aortic repair (OAR) and EVAR in sporadic AAA (spAAA) and fAAA patients in the Society for Vascular Surgery Vascular Quality Initiative.

METHODS

This was a retrospective review of all AAA repairs in the Vascular Quality Initiative from 2003 to 2017. Patients' data were summarized, and standard statistical analysis was performed. Patients with known genetic syndromes and centers with long-term follow-up of <50% of patients were excluded.

RESULTS

From 2003 to 2017, there were 1997 fAAA patients compared with 18,185 spAAA patients undergoing OAR and EVAR during the same study period. Compared with their spAAA counterparts, fAAA patients were younger (P < .001), were more likely to be living at home before surgery (P = .008), and demonstrated a lower incidence of coronary artery disease (P = .001) and hypertension (P = .039). Rates of smoking and end-stage renal disease did not differ between groups. However, fAAA patients were more likely to have aneurysmal degeneration of their iliac arteries (P < .001) and to undergo OAR (P < .001). When analyzing patients undergoing OAR, we found that fAAA patients were more likely to require concomitant renal bypass surgery (P = .012) but were extubated sooner (P = .005), received fewer blood transfusions (P < .001), and had a shorter length of stay (P = .018). Although individual complication rates did not differ between fAAA and spAAA groups after OAR, a composite end point of all early postoperative complications was decreased in fAAA patients (P = .020). When comparing fAAA and spAAA patients who underwent EVAR, we found a greater incidence of early lumbar branch endoleaks (type II) in fAAA patients; however, the rate of proximal type IA endoleaks (P = .279) and the rate of late reintervention for sac growth (P = .786), any endoleak (P = .439), or rupture (P = .649) did not differ between the groups. Whereas spAAA patients undergoing EVAR required longer postoperative intensive care unit stays (P < .001) and had a greater incidence of blood transfusions (P < .001), fAAA and spAAA patients had similar rates of postoperative complications (P = .510), 30-day mortality (P = .177), and long-term mortality (P = .259).

CONCLUSIONS

This study shows that patients with a familial form of AAA do not have increased morbidity or mortality after AAA repair. Our findings suggest that EVAR and OAR are both safe and effective for fAAA patients. Further studies with longer follow-up are needed to best care for this unique cohort of patients.

Risk of abdominal aortic aneurysm (AAA) among male and female relatives of AAA patients

Sex affects the presentation, treatment, and outcomes of abdominal aortic aneurysm (AAA). Although AAAs are less prevalent in women, at least in the general population, women with an AAA have a poorer prognosis in comparison to men. Sex differences in the genetic predisposition for aneurysm disease remain to be established. In this study we investigated the familial risk of AAA for women compared to men. All living AAA patients included in a 2004-2012 prospective database were invited to the multidisciplinary vascular/genetics outpatient clinic between 2009 and 2012 for assessment of family history using detailed questionnaires. AAA risk for male and female relatives was calculated separately and stratified by sex of the AAA patients. Families of 568 AAA patients were investigated and 22.5% of the patients had at least one affected relative. Female relatives had a 2.8-fold and male relatives had a 1.7-fold higher risk than the estimated sex-specific population risk. Relatives of female AAA patients had a higher aneurysm risk than relatives of male patients (9.0 vs 5.9%, p = 0.022), corresponding to 5.5- and 2.0-fold increases in aneurysm risk in the female and male relatives, respectively. The risk for aortic aneurysm in relatives of AAA patients is higher than expected from population risk. The excess risk is highest for the female relatives of AAA patients and for the relatives of female AAA patients. These findings endorse targeted AAA family screening for female and male relatives of all AAA patients.

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.

Family members of patients with abdominal aortic aneurysms are at increased risk for aneurysms: analysis of 618 probands and their families from the Liège AAA Family Study

BACKGROUND

The objectives were to answer the following questions with the help of a well-characterized population in Liège, Belgium: 1) what percentage of patients with abdominal aortic aneurysm (AAA) have a positive family history for AAA? 2) what is the prevalence of AAAs among relatives of patients with AAA? and 3) do familial and sporadic AAA cases differ in clinical characteristics?

METHODS

Patients with unrelated AAA diagnosed at the Cardiovascular Surgery Department, University Hospital of Liège, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. We divided the 618 patients into 2 study groups: group I, 296 patients with AAA (268; 91% men) were followed up with computerized tomography combined with positron emission tomography; and group II, 322 patients with AAA (295; 92% men) whose families were invited to ultrasonographic screening.

RESULTS

In the initial interview, 62 (10%) of the 618 patients with AAA reported a positive family history for AAA. Ultrasonographic screening identified 24 new AAAs among 186 relatives (≥50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonographic screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P < 0.0001).

CONCLUSIONS

The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis, and provide rationale for targeted screening of relatives of patients with AAA.

Genomic research to identify novel pathways in the development of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a common disease with a large heritable component. There is a need to improve our understanding of AAA pathogenesis in order to develop novel treatment paradigms. Genomewide association studies have revolutionized research into the genetic variants that underpin the development of many complex diseases including AAA. This article reviews the progress that has been made to date in this regard, including mechanisms by which loci identified by GWAS may contribute to the development of AAA. It also highlights potential post-GWAS analytical strategies to improve our understanding of the disease further.

Genome wide association studies of abdominal aortic aneurysms-biological insights and potential translation applications

Abdominal aortic aneurysm (AAA) is a complex disease with important environmental risk factors and a heritability of approximately 70%. Genome wide association studies have revolutionised the study of complex disorders and offer the potential for innovative insight into disease pathogenesis and development of individualised therapeutic options. This paper reviews the progress of genome wide association studies in AAA, highlighting novel disease pathways and potential translational applications of genomic discoveries.

C-reactive protein (CRP) elevation in patients with abdominal aortic aneurysm is independent of the most important CRP genetic polymorphism

OBJECTIVE

C-reactive protein (CRP) is a marker of cardiovascular disease. The objective was to determine if abdominal aortic aneurysm (AAA) and CRP serum concentration and its CRP gene are associated.

METHODS AND RESULTS

AAA patients and AAA negative controls were recruited. CRP concentration was measured and the single nucleotide polymorphism (SNP), rs3091244, assessed. AAA cases were divided into those measuring 30-55 mm and >55 mm in diameter, to assess correlation of CRP with AAA size. A total of 248 (227 male) cases and 400 (388 male) controls were included. CRP concentration was higher in cases (385.0 microl/dL [310.4-442.8] vs 180.3 microl/dL [168.1-196.9]; P < .0001). It was higher in large aneurysms (685.7 microl/dL [511.8-1083.0] vs 291.0 microl/dL [223.6-349.6]; P < .0001), with significant correlation observed to size (r = 0.37, P < .0001). CC was the most common SNP genotype with no difference in distribution (P = .43) between cases and controls. No difference existed in CRP for each genotype in the overall cohort (P = .17), cases (P = .18) and controls (P = .19).

CONCLUSION

The results demonstrate that CRP production may be related to the presence of AAA, especially in advanced disease. The serum concentration of CRP does not appear to be influenced by the functional SNP of the CRP gene, which also appears to have no association with AAA formation.