Familial aortic aneurysms: serum concentrations of triglyceride, cholesterol, HDL-cholesterol and (VLDL + LDL)-cholesterol

Bariatric surgery is associated with reduced admission for aortic dissection: a nationwide case-control analysis

BACKGROUND

Aortic dissection (AD) is an uncommon but life-threatening condition associated with high morbidity and mortality. Hypertension (HTN) and hyperlipidemia (HLD) are common modifiable risk factors.

OBJECTIVES

Since bariatric surgery is associated with remission of obesity-related co-morbidities, we hypothesize that surgical weight loss might be protective against this feared aortic pathology.

SETTING

A cross-sectional analysis was performed using the National Inpatient Sample database from 2010 to 2015.

METHODS

The treatment group included bariatric patients and the control group patients with obesity (body mass index [BMI] ≥ 35kg/m²) without previous bariatric surgery. Analyzed covariates included demographics, co-morbidities, aortic diseases, and AD. A multivariate logistic regression analysis (MLRA) was performed to assess the odds of admission for AD in both groups.

RESULTS

A total of 2,300,845 patients were identified (2,004,804 controls and 296,041 cases). The mean (SEM) age was 54.4 (.05) versus 51.9 (.05) years, for the control and treatment groups, respectively (P < .0001). Bariatric patients posed a significantly lower prevalence of type 2 diabetes (T2D), HTN, HLD, aortic aneurysm, and bicuspid aortic valve (P < .0001) than control subjects. In the control group, 1411 individuals (.070%) had AD, whereas only 94 patients (.032%) in the bariatric surgery group had such diagnosis (P < .0001). The MLRA showed that non-bariatric obese patients had a significantly higher likelihood of suffering from AD (OR = 1.8 [95%CI 1.44-2.29] P < .0001). Considering different age groups, bariatric surgery was found to be less associated with admission for AD for individuals below and above 40 years of age (OR = 2.95 [95%CI 1.09-7.99] P = .0345) and (OR = 1.75 [95%CI 1.38-2.22] P < .0001), respectively.

CONCLUSIONS

Bariatric surgery could be a protective factor against aortic dissection and should be considered in patients with obesity and risk factors for this cardiovascular complication.

Pathological Implication of Adipocytes in AAA Development and the Rupture

Abdominal aortic aneurysm (AAA) is a vascular disease that involves the gradual dilation of the abdominal aorta followed by its rupture. AAA is closely associated with weakening of the vascular wall due to oxidative stress, chronic inflammation, and degradation of the extracellular matrix. No effective drug therapy is currently available for preventing aneurysm progression or rupture. Adipocytes in the vascular wall are reportedly closely associated with AAA development and rupture. Fiber degradation in the aneurysm wall is enhanced by increased numbers of adipocytes, and rupture risk may increase as well. Recent studies suggested that appropriate control of adipocytes in the vascular wall may be an important strategy to prevent AAA rupture, and further studies may aid in the establishment of a method for preventing AAA rupture by therapeutic drugs or functional foods. In this review, we summarize adipocyte function and the correlation between AAA and adipocytes.

Elevated Plasma Levels of LDL Cholesterol Promote Dissecting Thoracic Aortic Aneurysms in Angiotensin II-Induced Mice

BACKGROUND

Plasma low-density lipoprotein (LDL) cholesterol is implicated in abdominal aorta (AA) and aortic dissection (AD); however, its role in the pathogenesis of AA and AD, a disease with a high mortality rate, is unknown. The existing animal models such as apolipoprotein E-deficient (Apoe^-/-) mice cannot reproduce all the conditions of AA/AD, including elevated LDL-cholesterol levels and spontaneous atheroma formation; therefore, a more reliable in vivo model is required. Here, we analyzed angiotensin II (Ang II)-induced mice with combined deficiency of the LDL receptor and the catalytic component of the apolipoprotein B-edisome complex (Ldlr^-/-/Apobec1^-/- [WKO]) to understand AA formation and AD occurrence in relation to plasma lipid composition.

METHODS

AAs and ADs were created in 18- to 22- week-old male Apoe^-/- and Ldlr^-/-/Apobec1^-/- mice by Ang II infusion. Immunostaining allowed assessment of smooth muscle cells and mural monocytes/macrophages.

RESULTS

Ldlr^-/-/Apobec1^-/- mice had elevated LDL-cholesterol levels characteristic for human type IIa hyperlipidemia, resulting in atherogenesis, which promoted mortality, AA formation, and AD development. Interestingly, variations in the distribution of atheromas and inflammatory sites between Apoe^-/- and Ldlr^-/-/Apobec1^-/- mice depending on lipid profiles resulted in differences in AA formation and AD occurrence in the thoracic aorta.

CONCLUSIONS

Our results indicate the presence of a pathogenic pathway involving serum lipid composition that plays a key role in AA formation and AD occurrence in Ang II-induced mice.

Adipocyte in vascular wall can induce the rupture of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a vascular disease involving the gradual dilation of the abdominal aorta. It has been reported that development of AAA is associated with inflammation of the vascular wall; however, the mechanism of AAA rupture is not fully understood. In this study, we investigated the mechanism underlying AAA rupture using a hypoperfusion-induced animal model. We found that the administration of triolein increased the AAA rupture rate in the animal model and that the number of adipocytes was increased in ruptured vascular walls compared to non-ruptured walls. In the ruptured group, macrophage infiltration and the protein levels of matrix metalloproteinases 2 and 9 were increased in the areas around adipocytes, while collagen-positive areas were decreased in the areas with adipocytes compared to those without adipocytes. The administration of fish oil, which suppresses adipocyte hypertrophy, decreased the number and size of adipocytes, as well as decreased the risk of AAA rupture ratio by 0.23 compared to the triolein administered group. In human AAA samples, the amount of triglyceride in the adventitia was correlated with the diameter of the AAA. These results suggest that AAA rupture is related to the abnormal appearance of adipocytes in the vascular wall.

Associations of ApoAI and ApoB-containing lipoproteins with AngII-induced abdominal aortic aneurysms in mice

OBJECTIVE

Dyslipidemia is implicated in abdominal aortic aneurysms (AAAs) in humans and angiotensin (Ang) II-infused mice. This study determined effects of major lipoprotein classes on AngII-induced AAAs using multiple mouse strains with dietary and pharmacological manipulations.

APPROACH AND RESULTS

Western diet had minor effects on plasma cholesterol concentrations and the low incidence of AngII-induced AAAs in C57BL/6J mice. Low incidence of AAAs in this strain was not attributed to protection from high-density lipoprotein, because apolipoprotein (apo) AI deficiency did not increase AngII-induced AAAs. ApoAI deletion also failed to alter AAA occurrence in hypercholesterolemic mice. Low-density lipoprotein receptor-/- mice fed normal diet had low incidence of AngII-induced AAAs. Western diet feeding of this strain provoked pronounced hypercholesterolemia because of increased apoB-containing lipoproteins with attendant increases of atherosclerosis in both sexes, but AAAs only in male mice. ApoE-deficient mice fed normal diet were modestly hypercholesterolemic, whereas this strain fed Western diet was severely hypercholesterolemic because of increased apoB-containing lipoprotein concentrations. The latter augmented atherosclerosis, but did not change the high incidence of AAAs in this strain. To determine whether reductions in apoB-containing lipoproteins influenced AngII-induced AAAs, ezetimibe was administered at a dose that partially reduced plasma cholesterol concentrations to ApoE-deficient mice fed Western diet. This decreased atherosclerosis, but not AAAs. This ezetimibe dose in ApoE-deficient mice fed normal diet significantly decreased plasma apoB-containing lipoprotein concentrations and reduced AngII-induced AAAs.

CONCLUSIONS

ApoB-containing lipoproteins contribute to augmentation of AngII-induced AAA in male mice. However, unlike atherosclerosis, AAA occurrence was not correlated with increases in plasma apoB-containing lipoprotein concentrations.

Interaction between widening of diameter of abdominal aorta and cardiovascular risk factors and atherosclerosis burden

The aim of this study was to investigate influence of traditional cardiovascular risk factors (CVRF) and subclinical atherosclerosis (ATS) burden on early stages of abdominal aortic diameter (AAD) widening among adults. 2,052 consecutive patients (P) (39 % women), mean age 52 ± 13 years, were prospectively screened for CVRF, ATS, and AAD. B-mode ultrasound was used to evaluate the largest AAD and to detect carotid and femoral atherosclerotic plaques. Mean AAD was 15.2 ± 2.8 mm. Atherosclerotic plaques were detected in 71 % of patients. Significant univariate correlation between AAD, traditional CVRF, and ABS was found. However, multiple regression analysis showed that only seven of them were significantly and weakly correlated with AAD (R² = 0.27, p < 0.001). On the other hand, a multivariate logistic analysis was used to evaluate CVRF impact on enlarged AAD ≥25 mm (EAAD) as compared to those with AAD <25 mm. These factors did not account for more than 30 % of interaction (R² = 0.30, p = 0.001). Furthermore, despite a large proportion of patients with high number of CVRF, and subclinical ATS, rate of patients with AAD ≥25 mm was low (1 %) and scattered regardless their CHD risk score or ATS burden. In conclusion, these results suggest that although some traditional CVRF and presence of ATS are associated with early stages of EAAD, other determinants still need to be identified for a better understanding of abdominal aortic aneurysm pathogenesis.

Abdominal aortic aneurysm: Treatment options, image visualizations and follow-up procedures

Abdominal aortic aneurysm is a common vascular disease that affects elderly population. Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm, however, endovascular aneurysm repair has rapidly expanded since its first introduction in 1990s. As a less invasive technique, endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair, especially in patients with co-morbid conditions. Computed tomography (CT) angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up. 2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair. CT has the disadvantage of high cummulative radiation dose, of particular concern in younger patients, since patients require regular imaging follow-ups after endovascular repair, thus, exposing patients to repeated radiation exposure for life. There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair. Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts, but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta. This article reviews the treatment options of abdominal aortic aneurysm, various image visualization tools, and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods. Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.

HDL antielastase activity prevents smooth muscle cell anoikis, a potential new antiatherogenic property

Various studies using proteomic approaches have shown that HDL can carry many proteins other than its constitutive apolipoprotein A-I (apoA-I). Using mass spectrometry and Western blotting, we showed the presence of alpha(1)-antitrypsin (AAT) (SERPINA1, serpin peptidase inhibitor, clade A, an elastase inhibitor) in HDL, isolated either by ultracentrifugation or by selected-affinity immunosorption using an anti-apoA-I column. Furthermore, we report that HDL possesses potent antielastase activity. We further showed that only HDL but not LDL is able to bind AAT. HDL-associated AAT was able to inhibit extracellular matrix degradation, cell detachment, and apoptosis induced by elastase in human vascular smooth muscle cells (VSMCs) and in mammary artery cultured ex vivo. Degradation of fibronectin by elastase used as a marker of pericellular proteolysis was prevented by addition of HDL. Elastase present in aortic abdominal aneurysm (AAA) thrombus samples was also able to induce apoptosis of VSMCs in culture. This phenomenon was prevented by addition of HDL but not of LDL. Finally, we report that the proportion of AAT in HDL isolated from patients with an AAA is decreased relative to that from matched control subjects, suggesting a reduced capacity of HDL to inhibit elastase in these patients. In conclusion, our data provide evidence of a new potential antiatherogenic property of HDL attributable to AAT and its antielastase activity.

Relation of common carotid artery lumen diameter to general arterial dilating diathesis and abdominal aortic aneurysms: the Tromsø Study

In a cross-sectional, population-based study in Tromsø, Norway, the authors investigated correlations between lumen diameter in the right common carotid artery (CCA) and the diameters of the femoral artery and abdominal aorta and whether CCA lumen diameter was a risk factor for abdominal aortic aneurysm (AAA). Ultrasonography was performed in 6,400 men and women aged 25-84 years during 1994-1995. An AAA was considered present if the aortic diameter at the level of renal arteries was greater than or equal to 35 mm, the infrarenal aortic diameter was greater than or equal to 5 mm larger than the diameter of the level of renal arteries, or a localized dilation of the aorta was present. CCA lumen diameter was positively correlated with abdominal aortic diameter (r = 0.3, P < 0.01) and femoral artery diameter (r = 0.2, P < 0.01). In a multivariable adjusted model, CCA lumen diameter was a significant predictor of AAA in both men and women (for the fifth quintile vs. the third, odds ratios were 1.9 (95% confidence interval: 1.2, 2.9) and 4.1 (95% confidence interval: 1.5, 10.8), respectively). Thus, CCA lumen diameter was positively correlated with femoral and abdominal aortic artery diameter and was an independent risk factor for AAA.

Inhibition of development of experimental aortic abdominal aneurysm in rat model by atorvastatin through inhibition of macrophage migration

Recently, atherosclerosis has been considered to be the result of inflammation. Interestingly, hydroxymethylglutaryl-coenzyme (HMG-Co) A inhibitors (statins), which are clinically used as lipid-lowering agents, have been reported to have various anti-inflammatory effects. As abdominal aortic aneurysm (AAA) is a common degenerative condition associated with atherosclerosis, this study was designed to investigate the inhibitory effect of a statin, atorvastatin, on aneurysm formation apart from its lipid-lowering effect. We employed an elastase-induced rat AAA model, as statins do not lower cholesterol in rats. Mean aneurysm diameter was significantly smaller in the atorvastatin treatment group as compared to control at 4 weeks after surgery (P<0.05). Interestingly, atorvastatin inhibited the expression of ICAM and MCP-1, followed by the suppression of macrophage recruitment into the aortic wall at 1 week after operation. A significant reduction in MMP-12, but not MMP-2, -3 and -9, expression was also observed by treatment with atorvastatin at 1 week after surgery. In addition, synthesis of collagen and elastin in the vascular wall were significantly increased by atorvastatin. Here, the present study demonstrated a direct effect of atorvastatin to inhibit the progression of aortic aneurysm, independent of its lipid-lowering effect. This study suggests new therapeutic aspects of statins to inhibit the progression of aneurysms.

Traditional and novel risk factors for clinically diagnosed abdominal aortic aneurysm: the Kaiser multiphasic health checkup cohort study

BACKGROUND

Identification of risk factors for and early diagnosis of clinically significant abdominal aortic aneurysm (AAA) before rupture is vital to optimize outcomes in these patients. Our aim was to examine traditional and three novel potential risk factors (abdominal obesity, white blood cell count, and kidney function) for abdominal aortic aneurysm (AAA, comprising discharge diagnosis or surgical repair) in a large multiethnic population.

METHODS

Cohort study (N =104,813) conducted at an integrated health care delivery system in northern California.

RESULTS

After a median of 13 years, 605 AAA events (490 in men and 115 in women; 91 [15%] fatal) were observed. In multivariable analysis, factors significantly associated with risk of clinically detected AAA included male gender, older age, black race (inversely), low educational attainment, cigarette smoking (with dose-response relation), height, treated and untreated hypertension, high total serum cholesterol, elevated white blood cell count, known coronary artery disease, history of intermittent claudication, and reduced kidney function. A significant Asian race by gender interaction was found such that Asian race had a (borderline significant) protective association with AAA in men but not in women.

CONCLUSIONS

Our findings confirm that major atherosclerotic risk factors, except for diabetes and obesity, are also prospectively related to AAA and suggest that elevated white blood cell count and reduced kidney function may improve risk stratification for clinically relevant AAA.

Hypertension accelerated experimental abdominal aortic aneurysm through upregulation of nuclear factor kappaB and Ets

In this study, we focused on the effect of hypertension on the transcription factors nuclear factor kappaB (NFkappaB) and ets in the mechanisms of abdominal aortic aneurysm (AAA), and we investigated how hypertension affects the progression of AAA. AAA was produced by elastase perfusion in hypertensive rats and normotensive rats. The size of AAA rapidly increased in hypertensive rats as compared with normotensive rats. Western blot analysis demonstrated that the expression of matrix metalloproteinase (MMP)-2, -3 , -9, and -12, as well as intercellular adhesion molecule, was increased in hypertensive AAA rats, accompanied by upregulation of NFkappaB and ets. Moreover, in situ zymography showed that the activity of MMPs was increased in the aorta of a hypertensive AAA model as compared with that in a normotensive AAA model. Interestingly, transfection of chimeric decoy oligodeoxynucleotide (ODN) resulted in significant inhibition of aortic dilatation both in normotensive and hypertensive rats at 4 weeks after transfection. Destruction of elastic fibers was also significantly inhibited by transfection of chimeric decoy ODN in both hypertensive rats and normotensive rats. The expression of MMP-2, -3, -9, and -12, as well as intercellular adhesion molecule, was significantly attenuated by the chimeric decoy ODN, accompanied by inhibition of the migration of macrophages. Also, the effect of chimeric decoy ODN was confirmed in an organ culture. The present study demonstrated that hypertension accelerated the progression of experimental AAA through upregulation of NFkappaB and ets. Inhibition of NFkappaB and ets could be a novel therapeutic strategy to treat AAA in hypertensive patients.

LDL Cholesterol is Associated with Small Abdominal Aortic Aneurysms

OBJECTIVE

To examine the relationship between serum lipids and abdominal aortic aneurysms (AAA).

METHODS

Two hundred and six males (>50 years) with AAA (> or =30 mm) detected in a population based screening programme were compared with 252 age-matched male controls in a nested case-control study. Smoking status, previous medical and family histories, height, weight, blood pressure, ankle brachial pressure index (ABPI) and non-fasting lipid profile were recorded.

RESULTS

Cases were found to have significantly higher LDL cholesterol than controls. LDL cholesterol was an independent predictor of the risk for aneurysms in a logistic regression model adjusting for smoking status, family history of AAA, history of ischaemic heart disease, presence of peripheral vascular disease, use of lipid lowering medication and treatment for hypertension. There was a linear effect with increased levels of LDL cholesterol increasing the risk of having a small aneurysm (test for trend p=0.03).

CONCLUSION

The highly significant association between LDL cholesterol and small aneurysms suggests that LDL, possibly acting via inflammatory mediated matrix degeneration, could be an initiating factor in the development of AAA. The ability of statin therapy to prevent AAA formation requires further investigation.

Abdominal aortic aneurysms in the New Zealand Maori population

Background

Abdominal aortic aneurysm (AAA) is believed to be a rare disease in people of non-European descent. Maori, New Zealand's indigenous people, are thought to originate from South East Asia, so their incidence of AAA might also be expected to be low. The aim was to investigate the incidence and phenotypic factors associated with AAA in the New Zealand Maori population.

Methods

A retrospective study was performed using the audit database of the New Zealand Society of Vascular Surgeons. Age-standardized rates of admission and death were calculated for Maori and non-Maori.

Results

Maori comprised 3·9 per cent of the population who had an AAA repaired, similar to the percentage of the Maori population aged over 65 years. However, the death rate from AAA in Maori was 2·4 times the rate in non-Maori. Maori were younger at diagnosis than non-Maori (65·2 versus 71·8 years; P &lt; 0·001), had more emergency procedures (46·6 versus 30·2 per cent; P = 0·018) and a significantly higher proportion of Maori admissions were for a ruptured aneurysm.

Conclusion

Maori had a higher mortality rate from AAA than non-Maori New Zealanders. Although admission rates between Maori and non-Maori were similar, the earlier age of onset and the increased proportion of ruptured aneurysms may indicate that the disease is more severe in Maori.

Life-style factors and risk for abdominal aortic aneurysm in a cohort of Finnish male smokers

Prospective studies evaluating risk factors for abdominal aortic aneurysm are few. We studied the association of life-style factors with risk for abdominal aortic aneurysm among 29,133 male smokers 50-69 years of age, participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. During a mean follow-up of 5.8 years, 181 were diagnosed with ruptured abdominal aortic aneurysm or nonruptured abdominal aortic aneurysm plus aneurysmectomy. Risk for abdominal aortic aneurysm was positively associated with age [relative risk (RR) = 4.56, 95% confidence interval (CI) = 2.42-8.61 for > 65 vs < or = 55 years], smoking years (RR = 2.25, 95% CI = 1.33-3.81 for > 40 vs < or = 32 years), systolic blood pressure (RR = 1.92, 95% CI = 1.13-3.25 for > 160 vs < or = 130 mmHg), diastolic blood pressure (RR = 1.80, 95% CI = 1.05-3.08 for > 100 vs < or = 85 mmHg), and serum total cholesterol (RR = 1.85, 95% CI = 1.09-3.12 for > 6.5 vs < or = 5.0 mmol/liter). High-density lipoprotein cholesterol showed a strong inverse association with risk for aortic aneurysm (RR = 0.16, 95% CI = 0.08-0.32 for > 1.5 vs < or = 0.9 mmol/liter). High energy intake was associated with lower risk for aortic aneurysm (RR = 0.59, 95% CI = 0.38-0.94 for the highest quartile vs the lowest), whereas no associations with nutrients were evident. We conclude that classical risk factors for atherosclerotic diseases seem to be important in pathogenesis of large abdominal aortic aneurysms.

Smoking, but not lipids, lipoprotein(a) and antibodies against oxidised LDL, is correlated to the expansion of abdominal aortic aneurysms

OBJECTIVES

to study the role of smoking, lipids, lipoprotein (a), and autoantibodies against oxidised low density lipoprotein (Ab-oxLDL) in the expansion of small abdominal aortic aneurysms (AAA). To study the role of Ab-oxLDL and lp(a) in the progression of lower limb atherosclerosis.

METHODS AND MATERIALS

one hundred and thirty-eight male patients with AAA were interviewed, examined, and their serum lipids and S-Ab-oxLDL determined. Of these, 117 were followed annually with ultrasound and underwent control scans and blood pressure measurements for a mean of 2.5 (range 1-5) years.

RESULTS

initial AAA size, smoking and level of triglycerides were positively correlated to increased aneurysmal expansion, while beta-blocker medication was associated with decreased expansion. Besides initial AAA size, only smoking had persisting significance after adjustment of the other significant variables. Initial ankle brachial pressure index (ABI) and Lp(A) but not ab-oxLDL were significantly correlated to ABI change.

CONCLUSION

smoking cessation may inhibit aneurysmal expansion. Lipids seem to play a minor role in the progression of AAA.

Common carotid intima-media thickness in patients with peripheral arterial disease or abdominal aortic aneurysm: the SMART study. Second Manifestations of ARTerial disease

Evidence is emerging that the contribution of atherosclerosis to the development of abdominal aortic aneurysm may differ from that of other manifestations of arterial disease. B-mode ultrasound may be helpful in understanding the characteristics and factors that contribute to the development of different manifestations of arterial disease. We examined whether there is a difference in common carotid intima-media thickness (IMT), an indicator of generalized atherosclerosis, in patients with peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA). IMT of the left and right common carotid artery was measured in the first 172 patients (123 PAD and 49 AAA) enrolled in the Second Manifestations of ARTerial disease (SMART) study, a cohort study among patients with a manifestation of atherosclerotic vascular disease or risk factors for atherosclerosis. Mean IMT was 0.98 +/- 0.34 mm in patients with PAD and 0.91 +/- 0.20 mm in patients with AAA, with an age and sex adjusted mean difference of 0.18 mm (95% CI 0.08; 0.28). After additional adjustments for cardiovascular risk factors, the difference remained 0.11 mm (95% Cl 0.01; 0.21). Common carotid IMT in patients with AAA is on average smaller than in patients with PAD, independent of other determinants of IMT. These findings support the view that the development of AAA cannot completely be explained by atherosclerosis and is in part due to other pathophysiological mechanisms.

Prevalence and risk factors for abdominal aortic aneurysms in older adults with and without isolated systolic hypertension

An association between abdominal aortic aneurysm (AAA) and atherosclerotic disease has been recognized and may be due to shared risk factors. A consistent relation between blood pressure and AAA has not been found. AAA was compared between those with and without isolated systolic hypertension (ISH) and prevalence of aortic atherosclerosis was evaluated. Abdominal aortic ultrasound was performed in 266 people, 143 with ISH and 123 age-similar controls. AAA was defined as an infrarenal aortic diameter of > or = 3.0 cm or an infrarenal-to-suprarenal diameter ratio of > or = 1.2. The average age of participants was 73 years. Overall prevalence of AAA was 9.4%, 11.9% in those with ISH and 6.5% among normotensives (p = 0.134). Multivariate analysis revealed male gender (p <0.001), higher low-density lipoprotein (p <0.001), higher pulse pressure (p = 0.032), and current smoking (p = 0.012) to be independent predictors of AAA. When evaluating aortic atherosclerosis, those with AAA had significantly larger diameters of the iliac arteries along with greater intimamedia thickness of the iliac arteries. Those with and without aneurysms had a similar prevalence of plaque (89% to 96%), but measured plaques tended to be larger among those with than without AAA (p <0.001). Progression of AAA after 1 year was observed in 8 participants, with a mean diameter change of 3.42 mm. AAA was found to be independently associated with pulse pressure but not with systolic blood pressure. Patients with AAA also had greater wall thickness and greater diameter of the iliac arteries, which are probably associated with the underlying disease process.

Prevalence of abdominal aortic aneurysms in men with diabetes

OBJECTIVE

To assess the prevalence of abdominal aortic aneurysm (AAA) in men with diabetes aged 60 years and over.

DESIGN

Prospective screening study.

PATIENTS

303 eligible participants among the first 1000 recruited to a large, community-based study of diabetes.

MAIN OUTCOME MEASURES

Aortic diameter > or = 30 mm on screening ultrasonography, or previous surgery for AAA.

RESULTS

AAA was diagnosed in three of the 303 men screened, and four others had previously had surgery for AAA. The aorta was not visualised in three obese men. Only one AAA required surgery (> or = 50 mm diameter). The overall prevalence of AAA was 2.3% (7/300), lower than that reported previously in the general population. Multivariate logistic regression analysis showed statistically significant associations with fasting triglyceride levels, and a history of intermittent claudication.

CONCLUSIONS

Although a small number of men with diabetes aged 60 or more have undiagnosed AAA, the prevalence does not appear to be high enough to warrant targeted ultrasound screening.

Biochemical and molecular genetic studies of abdominal aortic aneurysm in an Irish population

Abdominal aortic aneurysm (AAA) is a common disease of the elderly exhibiting a complex aetiology. In a survey of 82 Irish aneurysm patients, compared to 79 age- and sex-matched control subjects, we have investigated a number of potential biochemical and molecular genetic markers which are amenable to analysis from blood specimens and which might have predictive value for AAA. No significant differences were observed between patients and control subjects in relation to serum lipids, leucocyte elastase activity or serum alpha 1-antitrypsin concentration. We have used the polymerase chain reaction to screen the patient and control groups in search of disease-associated genetic variation on chromosome 16, particularly in the region of the Cholesteryl Ester Transfer Protein (CETP) gene. Although variation in allele frequencies was detected between patients and controls at the four marker loci studied, no significant gene-disease associations were detected. The absence of gene-disease associations in our study may indicate that the genetic component in the aetiology of AAA in Ireland differs from that in the UK. Alternatively, it may indicate that the high degree of polymorphism at microsatellite loci may make them unsuitable as markers for the study of gene-disease associations in moderately sized populations. We therefore conclude that the biochemical and molecular genetic markers which we have examined are of no predictive value, and that ultrasonography remains the screening modality of choice for abdominal aortic aneurysm.

Pathogenesis of abdominal aortic aneurysm

The pathogenesis of abdominal aortic aneurysm involves many factors acting over time. However, destruction of elastin in the aortic wall is a key event that shifts the load produced by blood pressure on to collagen. This is exacerbated in the presence of hypertension. Smoking and age are further important factors, as is the site; elastic lamellae are relatively less common in the abdominal aorta. Once the shielding effect of elastin is lost, further dilatation and rupture of the aorta depend on the physical properties of the collagen present.

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.

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.

Pathogenesis of acquired aneurysms of the abdominal aorta

The incidence of abdominal aortic aneurysm has recently increased. There is still no accurate definition of abdominal aortic aneurysm. The diameter of abdominal aortic aneurysms is the only factor permitting evaluation of the risk of rupture of aneurysms whose growth remains unpredictable. Abdominal aortic aneurysm is a multi-factorial disease associated with aortic aging and atheroma. It differs from stenotic disease by the intensity of degenerative or destructive phenomena in the media. Particular hemodynamic conditions in the infrarenal abdominal aorta seem to enhance the development of aneurysm at this level. While certain constitutional anomalies of the extracellular matrix of proteins seem to enhance the development of abdominal aortic aneurysm, protease activity of as yet undetermined origin also seems to play a prominent role. Family cases of abdominal aortic aneurysms have been reported but the mechanisms responsible remain to be determined. Several genetic markers have been suggested. The most reliable marker of aortic aneurysm is arteriomegaly.

Lp(a) lipoprotein in patients with arterial insufficiency of the lower extremities

The serum concentration of Lp(a) lipoprotein was determined in 66 patients with peripheral arterial insufficiency of the lower extremities (PAI) and 164 controls. The mean level was higher among the patients than among the controls (236 +/- 248 vs. 129 +/- 159 mg/l, p = 0.01), and values above 300 mg/l were more common among the patients (22/66 vs. 21/164, p less than 0.001). The difference between the 26 female patients and the 94 female controls was statistically significant (280 +/- 268 vs. 118 +/- 141 mg/l, p less than 0.001), but not the difference between the 40 male patients and the 70 male controls (208 +/- 235 vs. 142 +/- 182 mg/l). A high Lp(a) lipoprotein level was not associated with a high LDL-cholesterol level, and there was no significant correlation between the serum levels of Lp(a) lipoprotein and triglycerides++, total cholesterol or HDL-cholesterol. The results indicate, that high Lp(a) lipoprotein levels may be a risk factor for PAI in women.

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.

Ultrasonographic screening of the abdominal aorta among siblings of patients with abdominal aortic aneurysms

To evaluate the prevalence of abdominal aortic dilatations among asymptomatic brothers and sisters of patients with abdominal aortic aneurysms (AAAs), an ultrasonographic screening study was performed. One hundred and two siblings of patients operated on for AAAs at two Swedish hospitals were invited to attend, and 87 of them (35 men and 52 women) from 32 different families, accepted the invitation. Their median age was 63 years (range 39-82 years). Aortic dilatation was diagnosed in ten of the brothers (29 per cent) and three of the sisters (6 per cent). In ten cases (eight men and two women) there was a localized dilatation caudal to the coeliac axis, and in three a general dilatation of the abdominal aorta with the diameter at the coeliac axis greater than 29 mm. None of the aortic dilatations had been known before this study was performed. The conclusion is that the prevalence of asymptomatic aortic dilatations among brothers of patients with AAAs seems to be high and that this group should be selected for further screening studies.

Co-existence of abdominal aortic aneurysms and intracranial aneurysms

The occurrence of abdominal aortic aneurysms (AAAs) and intracranial aneurysms (IAs) in the same patient and in the same family was studied among 89 patients with AAAs and 485 patients with IAs. Among the AAA-patients two had IAs themselves and five had IAs in the family, whereas three IA-patients had AAAs themselves and eight had AAAs in the family. Moreover, one of the patients with both AAA and IA had a blood relative with AAA, and in six of the families with both types of aneurysms there were more than two subjects with aneurysms. The results indicate, that AAAs and IAs may have a common aetiologic factor.