Is abdominal aortic aneurysm familial?

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.

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.

Aneurisma da aorta abdominal infrarrenal: importância do rastreamento em hospitais do Sistema Único de Saúde na região metropolitana de Salvador - Bahia

INTRODUÇÃO: O aneurisma da aorta abdominal infrarrenal (AAA) representa doença vascular que merece constante atenção, tanto para os estudos de rastreamento como de aperfeiçoamento terapêutico. Sua importância clínica se baseia na alta taxa de mortalidade que ocorre com a sua ruptura, em contraste com a baixa taxa de mortalidade descrita com a correção cirúrgica eletiva em serviços especializados. Na região metropolitana de Salvador, não se encontram dados relativos à identificação desses indivíduos. Esse fato encorajou nosso estudo. OBJETIVOS: (1) determinar a prevalência do AAA infrarrenal nos pacientes com fatores de risco; (2) identificar esses fatores de risco; e (3) a população que deve ser rotineiramente rastreada. MÉTODOS: Em estudo de rastreamento do AAA realizado pelos Serviços de Cirurgia Vascular do Hospital Geral Roberto Santos (HGRS) e do Hospital Geral de Camaçari (HGC) de setembro de 2008 a outubro de 2009, foram selecionados 1350 indivíduos com 50 anos ou mais que apresentavam fatores de risco para o aneurisma da aorta. A triagem incluiu o preenchimento de protocolo e a realização de ultrassom doppler colorido. RESULTADOS: A prevalência do AAA infrarrenal nesta amostra foi 3,9%. Os fatores de risco mais frequentemente associados foram: média de idade de 72 anos, gênero masculino, tabagismo, antecedente de AAA e portadores de doença arterial oclusiva periférica, insuficiência coronariana e doença pulmonar obstrutiva crônica. O rastreamento do AAA deve ser considerado em homens com idade superior a 65 anos, principalmente quando presente um desses fatores de risco.

V, Caffaro RA. Fatores de morbimortalidade na cirurgia eletiva do aneurisma da aorta abdominal infra-renal: experiência de 134 casos

CONTEXTO: O tratamento cirúrgico convencional do aneurisma da aorta abdominal (AAA) infra-renal pode resultar em complicações graves. A fim de otimizar os resultados na evolução do tratamento, é importante que sejam identificados os pacientes predispostos a determinadas complicações e instituídas condutas preventivas. OBJETIVOS: Avaliar a taxa de mortalidade operatória precoce, analisar as complicações pós-operatórias e identificar os fatores de risco relacionados com a morbimortalidade. MÉTODO: Foram analisados 134 pacientes com AAA infra-renal submetidos a correção cirúrgica eletiva no período de fevereiro de 2001 a dezembro de 2005. RESULTADOS: A taxa de mortalidade foi de 5,2%, sendo secundária principalmente a infarto agudo de miocárdio (IAM) e isquemia mesentérica. As complicações cardíacas foram as mais freqüentes, seguidas das pulmonares e renais. A presença de diabetes melito (DM), insuficiência cardíaca congestiva (ICC), insuficiência coronariana (ICO) e cintilografia miocárdica positiva para isquemia estiveram associadas às complicações cardíacas. A idade avançada, a doença pulmonar obstrutiva crônica (DPOC) e a capacidade vital forçada reduzida aumentaram os riscos de atelectasia e pneumonia. História de nefropatia, tempo de pinçamento aórtico prolongado e níveis de uréia elevados aumentaram os riscos de insuficiência respiratória aguda (IRA). A isquemia dos membros inferiores esteve associada ao tabagismo e à idade avançada, e a maior taxa de mortalidade, à presença de coronariopatia, tempos prolongados de pinçamento aórtico e de cirurgia. CONCLUSÃO: A taxa de morbimortalidade esteve compatível com a literatura nacional e internacional, sendo secundária às complicações cardíacas, respiratórias e renais. Os fatores de risco identificados no pré e transoperatório estiveram relacionados com essas complicações.

Genome-wide approach to finding abdominal aortic aneurysm susceptibility genes in humans

Familial aggregation of abdominal aortic aneurysms (AAAs) is now widely recognized, however, susceptibility genes have not yet been identified. Our approach to find susceptibility genes has been to collect families with AAAs and to perform DNA linkage analyses to identify regions on the human chromosomes that are linked to AAAs and could harbor susceptibility genes for AAAs. We identified 233 families with at least two individuals diagnosed with AAAs. These families had 653 AAA patients and an average of 2.8 cases per family. When evaluating mode of inheritance, 167 (72%) families were consistent with autosomal recessive inheritance, whereas 58 (25%) families were consistent with autosomal dominant inheritance and in 8 families the familial aggregation could be explained by autosomal dominant inheritance with incomplete penetrance. Blood samples from 235 affected relative pairs (ARPs) and their unaffected relatives were collected for DNA isolation and the DNA used for genotyping with highly variable microsatellite markers. We included covariates in the statistical analyses to allow for genetic heterogeneity. The results for chromosomes 19g13 and 4q31 were significant with sex, number of affected first-degree relatives, and their interaction as covariates. These chromosomal regions contain many plausible candidate genes, and the future research will include more detailed analyses of these positional candidate genes.

French women from multiplex abdominal aortic aneurysm families should be screened

BACKGROUND

Multiplex abdominal aortic aneurysm families (MAAAFs) (> or =1 subject plus the proband) represent 1% to 34% of abdominal aortic aneurysm (AAA), but the percentage in France is unknown.

METHOD

The MAAAF rate was retrospectively defined by analysis of 3 groups: 72 of 104 consecutive individuals undergoing AAA surgery during 1994, 24 of 53 women and 35 of 76 men with giant (> or =9 cm) AAA operated on during 1986 to 1994. MAAAF characteristics were determined based on 10 families issued from these 3 groups and 34 others identified nationwide. Data were obtained from a standardized questionnaire for probands and relatives, detailed pedigrees of each family, and computed tomography (CT) scans without contrast medium of the aorta and lower limb arteries for first-degree relatives > or =40-year-of age.

RESULTS

The MAAAF rate was 4.2% for the consecutive-surgery patients (proband M/F ratio, 17:1; mean age at surgery, 68.5 +/- 8.5 years). CT detected no additional AAA among them (screened individuals M/F ratio, 0.63; mean age, 54.0 +/- 11.2 years). MAAAF rates were 8.3% and 14.3% for the women's and giant-AAA groups with CT screening, respectively. Characteristics were investigated in 104 affected subjects from 44 MAAAFs: female relatives were more often affected than probands (P < 0.025). Compared with men, affected female relatives were significantly older at diagnosis and surgery (P < 0.05 and P < 0.02, respectively), as were affected women (P < 0.02 and P < 0.01, respectively). CT scan screening identified significantly more AAA and abdominal aortic dilatations among the 44 MAAAFs than the consecutive-surgery group (5 and 4, respectively; P < 0.001).

CONCLUSION

Although the MAAAF rate seems low in France, women from MAAAF were affected more often and later, suggesting that they should be screened.

The lifetime prevalence of abdominal aortic aneurysms among siblings of aneurysm patients is eightfold higher than among siblings of spouses: an analysis of 187 aneurysm families in Nova Scotia, Canada

BACKGROUND

Abdominal aortic aneurysms (AAAs) are frequently familial. The aim of this study was to compare the prevalence of AAA among the siblings of AAA patients with that in the spouses' siblings.

METHODS

The siblings of 375 AAA patients and the siblings of the spouses of the AAA patients were included in this study and offered ultrasonography screening for AAA. Participants were asked to complete a questionnaire to collect demographic and general health information. Statistical analysis was done with Fisher's exact test. Odds ratios and 95% confidence intervals were also calculated.

RESULTS

Abdominal ultrasonography examinations were done for 309 individuals. The results indicated that 11 (11.2%) of 98 brothers of AAA patients, 4 (2.7%) of 147 sisters, and none of the 64 siblings of the spouses of the AAA patients were found to have an AAA. Combining the information from the ultrasonography screening and medical records on already known cases of AAA in these families, altogether 29.0% (44/152) of the brothers of AAA patients, 11.1% (20/181) of the sisters of AAA patients, and 2.3% (2/88) of the siblings of the spouses had an AAA.

CONCLUSION

There was a significant difference between the siblings of the AAA patients and those of the spouses both in the frequency of AAA detected by ultrasonography screening and in the overall prevalence of AAA. The overall prevalence of AAA in the siblings of AAA patients was about eight times that observed among the siblings of their spouses (19.2% vs 2.3%). These findings confirmed previous reports on high prevalence of AAA among siblings of AAA patients and emphasized the importance of an ultrasonography screening program for siblings of AAA patients.

Elective Versus Ruptured Abdominal Aortic Aneurysm Repair: A 1-Year Cost-Effectiveness Analysis

Abdominal aortic aneurysm (AAA) is a life-threatening condition with an overall mortality of 80%. It predominantly affects men 65-74 years of age and is caused by focal distension of the main blood vessel in the abdomen. Most patients go undetected until their aneurysm ruptures. Controversy surrounds the most appropriate form of screening for AAA. Currently, screening is only carried out selectively in patients with peripheral vascular disease. Some patients have their AAA detected incidentally, whilst ultrasound examination of the abdomen is carried out for other indications. These patients have the opportunity to undergo surveillance or elective surgery. The mortality rate of emergency surgical intervention following rupture (50%) is far worse in comparison to that of patients undergoing planned intervention under specialist vascular surgeons (5%). Despite improvements in outcomes from elective intervention for AAA as a result of specialisation, the overall mortality from this condition remains very high (80%) as the commonest presentation of an AAA is rupture. Screening all men aged 65-74 years is considered too costly in the current economic climate. However the cost difference between elective repair and emergency repair of AAA must be considered given that the outcome from elective AAA repair is far superior to that following ruptured AAA repair. Our objective was to retrospectively collect costs and outcomes of elective and emergency AAA repair in order to carry out a cost-effectiveness analysis. Four multiprofessional teams in accident and emergency, operation theatres, intensive care, and surgical wards at the Kent and Canterbury Hospital were selected from health-care professionals including doctors, managers, nurses, and clerical staff with the purpose of obtaining costs. Detailed cost data collection sheets were prepared to calculate costs, which included staff costs, consumables including drugs, intravenous fluids, equipment, investigations, laundry, catering, and stationery. An inventory of costs per item was obtained, and the total cost was calculated from the number of items used. Outcomes were measured in terms of survival. The total costs of emergency AAA repair were pounds sterling 96,700.69, with a cost per life saved of pounds sterling 24,175.17. The total cost of elective AAA repair was pounds sterling 76,583.22, with a cost per life saved of pounds sterling 5,470.23. Emergency intervention for AAA was found to cost five times more than a planned intervention per life saved per year.

Familial abdominal aortic aneurysm: a systematic review of a genetic background

BACKGROUND

Familial clustering of the abdominal aortic aneurysm (AAA) is clear, 12-19% of AAA patients have one or more first-degree relatives with an aneurysm and 4-19% is detected with ultrasound screening.

OBJECTIVES

To review the genetic background of AAA. DESIGN, METHODS AND MATERIALS: Computer searches of the MEDLINE, EMBASE, SUMsearch database and the Cochrane Library and searched reference lists of English language articles concerning the genetics of AAA, candidate gene approach and linkage analysis.

RESULTS

Brothers of AAA patients are at high risk to develop an AAA. The candidate gene approach was performed to detect defects in one of the components of the connective tissue, i.e. type I and III collagen, elastin and fibrillin, the inflammatory cell-derived matrix metalloproteinase, there inhibitors, auto-immune components and components related to atherosclerosis.

CONCLUSION

These studies give us insight in the pathology but do not lead to the specific genetic factor(s) responsible for (familial) AAA. Considering the supposed autosomal dominant inheritance, a gene mutation in one of the structural proteins of the connective tissue is expected. In the future, linkage analysis may resolve the genetic background of AAA.

The role of type III collagen in family members of patients with abdominal aortic aneurysms

OBJECTIVES

type III collagen is responsible for the tensile strength of the aorta-wall. To determine if genetic defect in the type III collagen production is associated with familial clustering of AAA.

METHODS

fifty-six patients with AAA and 82 first-degree family members participated. The medical and family histories were obtained. All these relatives were screened by ultrasound for AAA. In 58 relatives of 20 families, skin biopsies were taken for protein analysis to measure type III collagen production in cultured fibroblasts.

RESULTS

only one new AAA was detected in a brother of a patient. Four other relatives were already known with AAA. Three AAA patients had a type III collagen deficiency, but type III collagen was normal in all family members.

CONCLUSION

type III collagen deficiency does not appear to be an aetiological factor in the development of AAA.

Increased matrix metalloproteinase 2 expression in vascular smooth muscle cells cultured from abdominal aortic aneurysms

OBJECTIVES

Recent evidence has implicated matrix metalloproteinase 2 (MMP-2) in the pathogenesis of aneurysms. The aim of this study was to examine MMP-2 production and expression by aortic smooth muscle cells (SMCs) and dermal fibroblasts derived from patients with abdominal aortic aneurysms (AAAs).

METHODS

Aortic SMCs and dermal fibroblasts were cultured from patients with AAAs or from age-matched controls with atherosclerosis. The production of MMP and tissue inhibitor of metalloproteinase into culture media was analyzed with the use of gelatin zymography, Western blotting, and enzyme-linked immunosorbent assay. Gene expression was analyzed with Northern blotting.

RESULTS

All cells studied constitutively produced MMP-2. Aortic SMCs cultured from aneurysmal tissue expressed MMP-2 protein and messenger RNA at a significantly higher level than SMCs from controls (P =.008). Dermal fibroblasts from patients with AAAs expressed MMP-2 at a similar level to controls. In both cell types, tissue inhibitor of metalloproteinase 2 and membrane type 1-MMP were expressed at similar levels.

CONCLUSIONS

These data suggested that the regulation of MMP-2 gene expression was altered in the aortic SMCs of patients with aneurysms, but this finding was not repeated in other mesenchymal tissue.

Results of aortic screening in the brothers of patients who had elective aortic aneurysm repair

BACKGROUND

Brothers of patients with an abdominal aortic aneurysm (AAA) are at high risk. In the present study brothers of patients who underwent elective AAA surgery were invited for aneurysm screening and the psychological consequences studied.

METHODS

All brothers over the age of 50 years were invited for abdominal ultrasonography. They were asked to complete a standard psychological well-being questionnaire both before, and 3 months after screening.

RESULTS

Some 571 brothers were identified: 251 were dead, 35 lived abroad, 16 could not be contacted for other reasons, 46 refused to participate and 13 were already known to have an AAA. Some 210 subjects (37.8 per cent) accepted the offer of screening. A new AAA was detected in 26 (12.3 per cent, 95 per cent confidence interval 8-18 per cent) of the men screened resulting in an overall prevalence of 18 per cent (95 per cent confidence interval 13-26 per cent). Eight (3.8 per cent) aneurysms were 5 cm or more in diameter and elective surgery was performed in five patients (2.4 per cent). The psychological dimensions of well-being (depression, anxiety, energy, and positive well-being) had not changed significantly 3 months after screening.

CONCLUSION

The prevalence of AAA in brothers of patients with AAA is far higher than in the overall male population of the same age. Screening does not seem to have a negative influence on psychological well-being.

A prospective survey of patients presenting with abdominal aortic aneurysm

OBJECTIVES

To define the presentation and management of patients presenting with abdominal aortic aneurysm (AAA) DESIGN AND SETTING: A prospective survey was carried out of all patients presenting to hospitals within the Oxford region.

MATERIALS AND METHODS

Data were collected by one surgeon in each hospital. Full details were collected onto data sheets.

RESULTS

One hundred and ninety patients presented, 141 electively, 46 with ruptured AAA and three with acute AAAs. In 53 patients presenting electively the aneurysm was small and surveillance started. Fifty-six patients underwent an operation, three patients died. Of 46 patients with a ruptured aneurysm 24 (52%) died. In 11 no operation was carried out and all of these patients died within 24 h. Operative mortality was 13 of 35 patients (37%). More patients with a ruptured AAA were transferred to the teaching hospital compared with a district general hospital (p < 0.05). This was reflected in a lower operative mortality in the teaching hospital.

CONCLUSIONS

The presentation of AAA in this study was approximately 15 per 100,000 population. Approximately one-third of patients presenting electively had small AAAs which required surveillance. A further third underwent an operation, the remaining patients being unfit. Approximately one-quarter of patients with a ruptured aneurysm did not undergo an operation. The operative mortality was 37%.

The case against a national screening programme for aortic aneurysms

This review examines the assumptions underlying the calls for a national screening programme for aneurysms. It concludes that on the basis of published evidence, many of the necessary criteria for any putative screening programme are not met for this disease. Although the disease is an important cause of death, and a screening method is available, we lack basic knowledge about the natural history of the disease, especially small aneurysms, and about the cost-effectiveness of a screening programme. In particular, the treatment is an operation which, nationwide, carries a high mortality and is likely to be unacceptable to many patients. The consequences of such a programme would be to diagnose many small aneurysms, for which the best treatment remains unclear, and which will engender much unnecessary anxiety among patients so diagnosed.

Interaction between fibrillin genotype and blood pressure and the development of aneurysmal disease

Debate as to whether abdominal aortic aneurysms (AAA) are caused by atherosclerosis or whether they have a strong genetic etiology continues. We have investigated the hypothesis that risk factors are likely to be strongest in patients with generalized aneurysmal disease. We screened 232 consecutive AAA patients for popliteal aneurysm and investigated cardiovascular and genetic risk factors in these patients. Ultrasonography demonstrated the presence of a popliteal aneurysm in 24 of 232 (10%) patients. Multivariate analysis identified four independent factors associated with popliteal aneurysm: age (p = 0.013), height (p = 0.017), triglyceride concentration (p = 0.009), and systolic blood pressure (p = 0.037). In the AAA patients a significant association of fibrillin-1 genotype was present, determined by a tandem repeat polymorphism, with both systolic and pulse pressure. The genotypes associated with the highest pressures were significantly more common among the patients with popliteal aneurysm, p = 0.03. Following these findings we investigated whether there was an association between fibrillin-1 genotype and blood pressure in a healthy population, 245 men aged 50-61 years. Again we found a significant association between fibrillin genotype and pulse pressure, p = 0.003. We suggest that a strong interaction occurs between fibrillin genotype and blood pressure which contributes to the development of aneurysmal disease.

Sibling risks of abdominal aortic aneurysm

There is evidence that the risk of abdominal aortic aneurysm (AAA) is greater in first-degree relatives of patients with the disorder than in the same age group of the general population. We conducted a 3-year study of siblings of AAA probands and siblings of a control group (cataract surgery patients) of the same age. Genetic information was obtained by interview from 126 probands and 100 controls; another family member was present at the interview. Medical records were obtained and further information verified before a sibling (over age 50) was assigned affected status. Of 427 siblings of probands, 19 (4.4%) had probable or definite AAA, compared with five (1.1%) of 451 siblings of controls. The lifetime cumulative risks of AAA at age 83 were 11.7% (SD 3.1) and 7.5% (4.1), respectively. The risk of AAA began at an earlier age and increased more rapidly for probands' siblings than for controls' siblings (p < 0.01, log-rank test). A risk comparison, based on the results of ultrasound screening of 54 geographically accessible siblings of probands and the 100 controls showed a similar pattern. Ten (19%) siblings of probands and eight (8%) controls had AAA on ultrasound (lifetime cumulative risk 60.8% [18.9] vs 14.9% [5.1], p = 0.01). These results show that familial factors influence the age of onset of AAA. We recommend routine ultrasound examination of siblings of patients with AAA.

Abdominal aortic aneurysm in the Irish population: a familial screening study

A pilot screening programme was undertaken in Ireland to determine the incidence of abdominal aortic aneurysm (AAA) (diameter 3 cm or greater) in the siblings of 120 patients known to have AAA. There were 621 siblings; 270 of them were dead, 32 were over 80 years old and 85 lived outside Ireland, leaving 234 under 80 years of age still living in Ireland who were invited to attend for ultrasonographic screening. Of the 270 siblings who had died, 102 were women and 168 men; eight men (4.8 per cent) had died from ruptured AAA. Only 125 (53.4 percent) of the 234 siblings agreed to participate in the screening programme, 60 brothers from 31 families and 65 sisters from 35 families. Fifteen (12.0 per cent) of the 125 siblings had an AAA (median size 4.2 (range 3.1-6.8) cm), 13 (22 per cent) of the 60 male siblings and two (3 per cent) of the 65 female siblings. The prevalence of AAA among siblings was not affected by the age or sex of the patient with aneurysm. Seven of the 14 male siblings with hypertension had an AAA, compared with only six of the 46 who were normotensive (P = 0.01). The high incidence of AAA in brothers of affected patients highlights the need to counsel this group on their risk of aneurysm. The relatively low participation rate by siblings in this screening programme indicates that a hospital-based unit is unlikely to be effective in recruiting all patient siblings at risk from an AAA.

Presentation and patterns of aortic aneurysms in young patients

PURPOSE

Although aortic aneurysm (AA) is primarily a disease of older age groups, younger (< 51 years) patients infrequently are admitted requiring AA surgery. We sought to compare the characteristics of these patients with those of a randomly selected group of older patients with AA.

METHODS

We identified 26 patients with AA (group I) under age 51 (mean age 44.8) treated surgically between 1977 and 1993, after excluding patients with acute aortic dissection, traumatic pseudoaneurysms, and ascending or arch aneurysms, and compared them with 75 randomly selected patients with AA between the ages of 65 and 75 (mean age 70.3) who were surgically treated during the same time period (group II).

RESULTS

Prevalence of hypertension, diabetes, coexisting heart, kidney, or occlusive peripheral vascular disease was similar between the two groups, and familial aneurysm rates and sex distribution did not differ significantly. More patients in group I had symptoms at the time of presentation (46% vs 6.7%, p < 0.001), and they also had larger AAs (6.9 cm vs 6.0 cm, p = 0.01). Definable causes of aneurysmal disease, such as Takayasu's, Cogan's, and Marfan syndromes, were more common among the young patients (23% vs 0%, p = 0.01), but most (77%) young patients did not have an identifiable syndrome associated with their aneurysm disease. Group I had a marked shift toward proximal aneurysms, defined as involvement of juxtarenal, suprarenal, or thoracoabdominal aorta (46% vs 18% in group II, p < 0.01). This difference persisted even when aneurysms associated with the above syndromes were excluded from consideration (p = 0.02). Cigarette smoking was much more common among the young patients (83% vs 51% in group II, p < 0.01). Smoking in group II was associated with more extensive aneurysm disease (p = 0.04).

CONCLUSIONS

Aneurysmal disease presenting in the young adult is more likely to be symptomatic and associated with more proximal aortic involvement than aneurysmal disease in older patients. Smoking appears to play an important role in the pathogenesis of aneurysmal disease in the young patient and was associated in our study with more proximal aneurysms among older patients. A subgroup of patients at risk for early and aggressive aneurysm disease is suggested by these data.

Familial abdominal aortic aneurysm: prevalence and implications for screening

The high prevalence of abdominal aortic aneurysm (AAA) in men over the age of 65 has led to the establishment of ultrasound screening programmes for this group. The apparent familial tendency towards AAA formation suggests that relatives of aneurysm patients may form another subpopulation in whom screening is appropriate. The first degree relatives of 100 consecutive aneurysm patients were identified. Of 110 relatives over 50 years of age, two were known to have had AAA and ultrasound scans were performed on 74, providing information on aortic size for 76 relatives (69%). No further aortic aneurysms (antero-posterior diameter > or = 4.0 cm) were found on scanning. However, nine relatives were demonstrated to have aortic dilatation (2.5-3.9 cm). Aortic dilatation was observed in 21% of male first degree relatives over 50 years of age, affecting 27% of sons and 17% of brothers. Only 4% of the sisters and none of the daughters were found to have aortic dilatation. The prevalence of aortic enlargement seems to be sufficiently high amongst male first degree relatives of AAA patients over 50 years of age to justify aortic screening.

Influence of type III collagen genotype on aortic diameter and disease

Type III collagen contributes to the tensile strength of the aortic wall, and mutations in the type III collagen gene have been suggested as the basis for the familial tendency to abdominal aortic aneurysm (AAA). Variation in this gene was investigated in 153 patients with AAA, 87 with aortoiliac stenosis and 98 age-matched controls. The rare mutation at amino acid 619 of Gly-->Arg, previously associated with AAA in a single family, was not found in any of the patients with aneurysm. For the Ala-->Thr variation at amino acid 531, the frequency of the threonine allele was 0.25 in patients with AAA and stenosis, compared with 0.35 in controls. The frequency of the rare allele in the region 3' to the gene demonstrated by Ava II digestion (0.27 in the general population) was found to be 0.29 in the AAA group and 0.19 in the stenosis group (P = 0.023). In the AAA group the presence of the Ava II rare allele was associated with a significant increase in aneurysm diameter (P = 0.044). Non-invasive assessment of aortic distensibility was available in 25 patients: those carrying the Ava II rare allele had less distensible aortas than those not carrying this allele (median pressure-strain elastic modulus 42.0 and 23.9 N/cm2 respectively, P = 0.008). Variation in the type III collagen gene may influence the mechanical properties of the ageing aorta and hence its susceptibility to disease and dilatation. In contrast, there is no evidence for a single common founder mutation in type III collagen predisposing to AAA.

Prevalence of abdominal aortic aneurysm in the offspring of patients dying from aneurysm rupture

The prevalence of abdominal aortic aneurysm (AAA) is high in the brothers of patients with aneurysm. A genetic component in the development of AAA has, therefore, been postulated. In this study the offspring of patients who had died from AAA rupture were invited to undergo ultrasonography of the abdominal aorta. The attendance rate was 69 per cent. Thirty-nine sons of median age 60 (range 45-75) years and 23 daughters of median age 62 (range 42-80) years were examined. Abdominal aortic dilatation was found in eight men and one woman. The presence of aortic dilatation in these nine cases was not related to age, hypertension, smoking or symptoms of occlusive arterial disease. It is concluded that the sons of those who have died from ruptured AAA constitute a high-risk group for the development of this condition and should be considered for further screening.

Selection for screening for familial aortic aneurysms

The reported familial clustering of abdominal aortic aneurysm (AAA) indicates the possible rewards of family-based screening programmes with respect both to the number of asymptomatic aneurysms detected and to identifying associated genes. Ultrasonographic screening of 28 families (25 brothers and 28 sisters) was carried out together with collecting a history and a blood sample for analysis of the cholesterol level and genetic markers. Among the screened siblings six (11 per cent), all > 60 years old, had an AAA > or = 3.0 cm in diameter. A further 11 siblings (21 per cent), six of whom were < 60 years old, had a wide (2.5-2.9 cm) aorta. The presence of an aneurysmal or wide aorta was significantly associated with smoking (P = 0.027), male sex (P = 0.008) and a proband age of < 60 years (P = 0.031). Polymorphic genetic markers for type III collagen and haptoglobin were not informative in these families. These results indicate that the efficiency of screening siblings of patients with AAA could be improved by limiting it to brothers with a smoking history and/or siblings of younger patients. The familial component appears to be greatest in these younger patients.

Smooth muscle cell elastase, atherosclerosis, and abdominal aortic aneurysms

Smooth muscle cells (SMC) were obtained by outgrowth of human aortic explants from abdominal aortic aneurysm (AAA) patients, aortic occlusive disease (AOD) patients, and transplant donors (controls). Specimens were incubated with medium alone or medium with either elastin-derived peptides (EDP, 5 micrograms/mL) or low-density lipoproteins (LDL, 5 micrograms/mL). Elastase activity (ng/mg total protein) was assayed from 4-week-old cultures. Control aortas obtained from patients significantly younger secrete an increased amount of elastase at baseline compared with AOD and AAA patients (p less than 0.05). Elastin-derived peptides caused a significant increase in elastase secretion in all groups. The increase in elastase secretion in response to EDP in AAA patients was significantly higher compared with AOD or control. Low-density lipoprotein had no effect on SMC elastase secretion. These data suggest that (1) aortic SMCs secrete elastase in response to EDP, (2) SMC elastase is age dependent, and (3) AAA SMC secrete an abnormally high amount of elastase compared with AOD and control aortas in response to EDP. Like the neutrophil, the SMC is highly responsive to the degradation products of elastin and in AAA patients secrete significantly increased amounts of elastase in response to the breakdown products of atherosclerosis.

Abdominal aortic aneurysm, glaucoma and deafness: a new familial syndrome

Several reports have suggested a genetic basis for the distribution of abdominal aortic aneurysm (AAA) in some families. The familial clustering of this disease is further demonstrated in this report of ten siblings, five of whom have confirmed AAA. This is the largest cluster so far reported. The majority of patients in this family group also have glaucoma and/or deafness.

Prevalence of abdominal aortic aneurysm in patients with occlusive peripheral vascular disease

Over a 1-year period, 242 patients with peripheral vascular disease underwent abdominal ultrasonography to detect the presence of an abdominal aortic aneurysm. In 34 (14 per cent) an abdominal aortic aneurysm was found; half of these aneurysms were greater than 4 cm in diameter. In addition, 16 patients had ectatic aortas. Abdominal aortic aneurysms were more common in men than in women (17 versus 8 per cent). Patients with claudication were as likely to have an abdominal aortic aneurysm as those with rest pain or gangrene. The presence of aortoiliac occlusive disease increased the chance of an aneurysm being present (P less than 0.02). Patients with occlusive peripheral vascular disease are a high-risk group with regard to the development of an abdominal aortic aneurysm. Patients with proximal occlusive disease represent a subgroup at even higher risk.

Genetic variants of collagen III and abdominal aortic aneurysm

Collagens provide the tensile strength of the aortic wall. Variations in collagen structure are recognised in Ehlers Danlos syndrome type IV and could also be associated with a predisposition to aortic aneurysm. The frequency of some minor genetic variants of type III collagen, present in the normal population, can be detected by restriction enzyme digestion of genomic DNA from peripheral leucocytes. The frequency of a minor collagen type III allele demonstrated with the restriction enzyme Ava II was compared in patients with abdominal aortic aneurysm (n = 70) and aortoiliac stenosis (n = 47). The frequency of the minor allele was significantly higher in aneurysm patients (0.30) compared with patients with aortoiliac stenosis (0.17), p less than 0.05. The presence of the minor allele was associated with a less elastic aneurysm wall (median pressure strain elastic modulus 4575, n = 7), compared with patients homozygous for the common allele (median pressure strain elastic modulus 1990, n = 6), p less than 0.05. These results indicate that genetic variants of type III collagen may influence the extensile properties of the aortic wall and that mutations in the type III collagen gene may be associated with aortic aneurysms.

Predictors of death from aortic aneurysm among middle-aged men: the Whitehall study

Among 18,403 male civil servants examined at age 40-64 years there were 99 deaths attributed to aortic aneurysm during 18 years of follow-up. Each case was matched by age to ten controls who survived longer than the case. The risk of all types of fatal aneurysm was substantially increased for current smokers of manufactured cigarettes (rate ratio compared with lifelong non-smokers = 6.5; 95 per cent confidence interval 2.3-18.7), pipe or cigars (6.7; 1.7-26.5) and hand-rolled cigarettes (25.0; 7.5-83.3). Diastolic blood pressure was strongly associated with dissecting aneurysm (rate ratio per 10 mmHg increase = 2.4; 95 per cent confidence interval 1.7-3.2) and abdominal aneurysm (1.5; 1.2-1.9) but not other aneurysms (1.0; 0.7-1.5). The independent effects of height, adiposity, plasma cholesterol, glucose intolerance, reported angina and intermittent claudication were not significant. Hypertension and smoking, particularly of hand-rolled cigarettes, are confirmed as major and potentially remediable risk factors for fatal aortic aneurysm.

Abdominal aortic aneurysm: results of a family study

Data pertaining to abdominal aortic aneurysm among first-degree relatives of 91 patients with abdominal aortic aneurysm are presented. The percentage of families with at least one affected first-degree relative of the proband (multiplex families) was 15.4%. In 21.4% of multiplex families parent-offspring transmission of abdominal aortic aneurysm was noted; in the remaining families only siblings were affected. The mean age at onset among probands was 67.3 years; that among all affected was 67.4 years. No statistically significant difference in the mean ages at onset between genders was noted. Among affected siblings of probands, the sex ratio, male:female, was 1.33:1, which is not significantly different from 1:1. The relative risk of developing an abdominal aortic aneurysm was 3.97 for fathers, 4.03 for mothers, 9.92 for brothers, and 22.93 for sisters.

On the inheritance of abdominal aortic aneurysm

To determine the mode of inheritance of abdominal aortic aneurysm, data on first-degree relatives of 91 probands were collected. Results of segregation analysis performed on these data are reported. Many models, including nongenetic and genetic models, were compared using likelihood methods. The nongenetic model was rejected; statistically significant evidence in favor of a genetic model was found. Among the many genetic models compared, the most parsimonious genetic model was that susceptibility to abdominal aortic aneurysm is determined by a recessive gene at an autosomal diallelic major locus. A multifactorial component in addition to the major locus does not increase the likelihood of the data significantly.