Tobacco smoking and aortic aneurysm: Two population-based studies

Promising Novel Therapies in the Treatment of Aortic and Visceral Aneurysms

Aortic and visceral aneurysms affect large arterial vessels, including the thoracic and abdominal aorta, as well as visceral arterial branches, such as the splenic, hepatic, and mesenteric arteries, respectively. Although these clinical entities have not been equally researched, it seems that they might share certain common pathophysiological changes and molecular mechanisms. The yet limited published data, with regard to newly designed, novel therapies, could serve as a nidus for the evaluation and potential implementation of such treatments in large artery aneurysms. In both animal models and clinical trials, various novel treatments have been employed in an attempt to not only reduce the complications of the already implemented modalities, through manufacturing of more durable materials, but also to regenerate or replace affected tissues themselves. Cellular populations like stem and differentiated vascular cell types, large diameter tissue-engineered vascular grafts (TEVGs), and various molecules and biological factors that might target aspects of the pathophysiological process, including cell-adhesion stabilizers, metalloproteinase inhibitors, and miRNAs, could potentially contribute significantly to the treatment of these types of aneurysms. In this narrative review, we sought to collect and present relevant evidence in the literature, in an effort to unveil promising biological therapies, possibly applicable to the treatment of aortic aneurysms, both thoracic and abdominal, as well as visceral aneurysms.

Age, sex and angiographic type-related phenotypic differences in inpatients with Takayasu arteritis: A 13-year retrospective study at a national referral center in China

Backgrounds

We aimed to investigate the demographic characteristics, vascular involvement, angiographic patterns, complications, and associations of these variables in a large sample of TAK patients at a national referral center in China.

Methods

The medical records of TAK patients discharged from 2008 to 2020 were retrieved from the hospital discharge database using ICD-10 codes. Demographic data, vascular lesions, Numano classifications and complications were collected and analyzed.

Results

The median age at onset was 25 years in 852 TAK patients (670 female, 182 male). Compared with the females, the male patients were more likely to have type IV and were more likely to have iliac (24.7% vs. 10.0%) and renal artery (62.7% vs. 53.9%) involvement. They also had a higher prevalence of systemic hypertension (62.1% vs. 42.4%), renal dysfunction (12.6% vs. 7.8%) and aortic aneurysm (AA) (8.2% vs. 3.6%). The childhood-onset group was more likely to have involvement of the abdominal aorta (68.4% vs. 52.1%), renal artery (69.0% vs. 51.8%) and superior mesenteric artery (41.5% vs. 28.5%), and they were more likely to have type IV, V and hypertension than the adult-onset group. After adjusting for sex and age at onset, the patients with type II were associated with an increased risk of cardiac dysfunction (II vs. I: OR = 5.42; II vs. IV: OR = 2.63) and pulmonary hypertension (II vs. I: OR = 4.78; II vs. IV: OR = 3.95) compared with those with types I and IV. Valvular abnormalities (61.0%) were observed to be most prevalent in patients with type IIa. The patients with Type III were associated with a higher risk of aortic aneurysm (23.3%) than the patients with types IV (OR = 11.00) and V (OR = 5.98). The patients with types III and IV were more commonly complicated with systemic hypertension than the patients with types I, II and V. P < 0.05 in all of the above comparisons.

Conclusion

Sex, adult/childhood presentation and Numano angiographic type were significantly associated with differences in phenotypic manifestations, especially cardiopulmonary abnormalities, systemic hypertension, renal dysfunction and aortic aneurysm.

Association of cardiovascular risk factors and lifestyle behaviors with aortic aneurysm: A Mendelian randomization study

Objective: To examine the causality between hypertension, diabetes, other cardiovascular risk factors, lifestyle behaviors, and the aortic aneurysm among patients of European ancestry.

Methods: We performed two-sample Mendelian randomization (MR) analysis to investigate the causality of 12 modifiable risk factors with aortic aneurysm, including hypertension, body mass index (BMI), waist–hip ratio (WHR), diabetes, tobacco smoking, alcohol and coffee consumption, physical activity, and sleep duration. Genome-wide significant genetic instruments (p < 5 × 10^–8) for risk factors were extracted from European-descent genome-wide association studies, whereas aortic aneurysm genetic instruments were selected from the UK Biobank and FinnGen cohort. The inverse-variance weighted MR was used as the main analysis, and MR-Egger (MRE), weighted median MR, MR pleiotropy residual sum and outlier, and Phenoscanner searching were performed as sensitivity analyses. Furthermore, we calculated MRE intercept to detect pleiotropy and Cochran’s Q statistics to assess heterogeneity and conducted bidirectional MR and MR Steiger tests to exclude the possibility of reverse causality.

Results: We observed significantly higher risks for the aortic aneurysm in hypertension [pooled OR: 4.30 (95% CI 2.84–6.52)], BMI [OR: 1.58 (95% CI 1.37–1.81)], WHR [OR: 1.51 (95% CI 1.21–1.88)], WHR adjusted for BMI (WHRadjBMI) [OR: 1.35 (95% CI 1.12–1.63)], age of smoking initiation [OR: 1.63 (95% CI 1.18–2.26)], and tobacco use (initiation, cessation, and heaviness) [OR: 2.88 (95% CI 1.85–2.26)]. In sensitivity analysis, the causal effects of hypertension, BMI, WHRadjBMI, and tobacco use (initiation, cessation, and heaviness) remained robust.

Conclusion: There was a positive causal relationship between hypertension, BMI, WHR, and WHRadjBMI and aortic aneurysm.

Smoking Cessation and Mortality from Aortic Dissection and Aneurysm: Findings from the Japan Collaborative Cohort (JACC) Study

AIMS

Active cigarette smoking was intensively reported to increase the risk of aortic mortality while research on the association between smoking cessation and aortic mortality remains scarce. This study aimed to reconfirm the associations of exposure to cigarettes and smoking cessation associated with aortic mortality in a large Japanese population.

METHODS

In the Japan Collaborative Cohort (JACC) Study, 91,141 residents (57±10 years; men, 43%) who were free of stroke, coronary heart disease, and cancer were followed up from 1989-90 until 2009 during which 110 deaths from aortic dissection and 112 deaths from aneurysm were identified. Cox proportional hazard model was used to estimate multivariable hazard ratios (95%CI) for total and specific aortic mortality.

RESULTS

Compared to never smoking, HRs for total aortic mortality were 2.39 (1.40-4.08) for ＜20, 3.57 (2.19-5.83)for 20-39, and 3.92 (2.37-6.48) for ≥ 40 pack-years exposure. Compared to current smoking, HRs for total aortic mortality were 0.42 (0.18-0.97) for 10-15 years, 0.27 (0.11-0.66) for ＞15 years of cessation, and 0.24 (0.13-0.44) for never smoking. Similar inverse dose-response pattern was observed between smoking cessation duration and risk of mortality from aortic aneurysm (p for trend=0.001), but the association with aortic dissection mortality did not reach statistical significance.

CONCLUSIONS

Cigarette smoking was associated with an increased risk of aortic mortality while smoking cessation was so with a reduced risk among the Japanese population.

Disintegrin and Metalloproteinases (ADAMs [A Disintegrin and Metalloproteinase] and ADAMTSs [ADAMs With a Thrombospondin Motif]) in Aortic Aneurysm

Aortic aneurysm is a complex pathology that can be lethal if not detected in time. Although several molecular mechanisms and pathways have been identified to be involved in aortic aneurysm development and growth, the current lack of an effective pharmacological treatment highlights the need for a more thorough understanding of the factors that regulate the remodeling of the aortic wall in response to triggers that lead to aneurysm formation. This task is further complicated by the regional heterogeneity of the aorta and that thoracic and abdominal aortic aneurysm are distinct pathologies with different risk factors and distinct course of progression. ADAMs (a disintegrin and metalloproteinases) and ADAMTS (ADAMs with a thrombospondin motif) are proteinases that share similarities with other proteinases but possess unique and diverse properties that place them in a category of their own. In this review, we discuss what is known on how ADAMs and ADAMTSs are altered in abdominal aortic aneurysm and thoracic aortic aneurysm in patients, in different animal models, and their role in regulating the function of different vascular and inflammatory cell types. A full understanding of the role of ADAMs and ADAMTSs in aortic aneurysm will help reveal a more complete understanding of the underlying mechanism driving aneurysm formation, which will help towards developing an effective treatment in preventing or limiting the growth of aortic aneurysm.

Smoking and the Pathophysiology of Peripheral Artery Disease

Smoking is one of the most important preventable factors causing peripheral artery disease (PAD). The purpose of this review is to comprehensively analyze and summarize the pathogenesis and clinical characteristics of smoking in PAD based on existing clinical, in vivo, and in vitro studies. Extensive searches and literature reviews have shown that a large amount of data exists on the pathological process underlying the effects of cigarette smoke and its components on PAD through various mechanisms. Cigarette smoke extracts (CSE) induce endothelial cell dysfunction, smooth muscle cell remodeling and macrophage phenotypic transformation through multiple molecular mechanisms. These pathological changes are the molecular basis for the occurrence and development of peripheral vascular diseases. With few discussions on the topic, we will summarize recent insights into the effect of smoking on regulating PAD through multiple pathways and its possible pathogenic mechanism.

Diabetes, its duration, and the long-term risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

We aimed at comprehensively evaluate the independent association of diabetes and its duration with incident abdominal aortic aneurysm (AAA) and aortic diameter.

METHODS AND RESULTS

We prospectively studied incident AAA according to baseline glycemic status (diabetes, prediabetes, normal glycemia) in 13,116 ARIC participants (1990-1992) and the time-varying exposure of duration post incident diabetes in 11,675 participants (1987-1989) using Cox models. Additionally, we cross-sectionally explored ultrasound-based abdominal aortic diameter by glycemic status and cumulative duration of diabetes in 4710 participants (2011-2013) using linear regression models. Over ~20 years of follow-up, diabetes (vs. normal glycemia) at baseline was independently associated with lower AAA risk (489 cases) (hazard ratio: 0.71 [95%CI 0.51-0.99]), especially after 10 years (hazard ratio: 0.58 [0.38-0.87]). Prediabetes did not demonstrate an independent association. The inverse association was more evident with longer duration of diabetes (p for trend = 0.045), with 30-50% lower risk in eight years after diabetes diagnosis. The cross-sectional analysis demonstrated smaller aortic diameters with longer duration of diabetes (e.g., -0.76 mm [-1.24, -0.28] in diabetes with 8-12 years) compared to non-diabetes, whereas prediabetes consistently showed nominally greater diameter.

CONCLUSIONS

Diabetes, especially with longer duration, but not prediabetes, was independently associated with lower risk of AAA and smaller aortic diameter. Our findings suggest that long lasting clinical hyperglycemia plays an important role in the reduced AAA risk, and the reduced aortic diameter may be a structural mechanism behind this paradoxical association.

Diagnostic approach and management of genetic aortopathies

Aortic aneurysms were the primary cause of nearly 10,000 deaths in 2014 according to data from the Centers for Disease Control and may involve segments of the thoracic or abdominal aorta. Thoracic aortic aneurysms and dissections are more commonly associated with an underlying genetic etiology. In the past several decades, in parallel with the burst of new genome sequencing technologies, a number of genetic aortopathies have been identified. These have provided important insights into the molecular mechanisms of aneurysmal disease, but pose challenges in clinical practice as there are limited consensus recommendations at this time. In this review, we aim to address the pathophysiology, clinical presentation, and treatment considerations in the key heritable thoracic aortopathies.

A quantitative bias analysis of the confounding effects due to smoking on the association between fluoroquinolones and risk of aortic aneurysm

PURPOSE

Epidemiologic studies consistently report an increased risk of aortic aneurysm (AA) among users of fluoroquinolones (FQ), but confounding by smoking could explain all or some of the observed risk. Therefore, to better elucidate the potential causal impact of FQ on AA, we quantitatively evaluated the potential confounding effect of smoking on this observed association.

METHODS

We conducted a series of quantitative bias analyses using three previously published approaches: the E-value approach, the rule-out approach, and the array approach. We additionally conducted a numerical comparison between the rule-out approach and the E-value approach.

RESULTS

For an apparent relative risk of 2, the E-value is 3.41, suggesting that smoking needs to be associated with both FQ and AA with a minimal magnitude of 3.41 to explain away the observed twofold FQ-AA association. The array approach found that the prevalence of smoking among FQ users would need to be at least 2.9 times higher (43%) than the nonusers (15%), assuming smoking increases the risk of AA by 7.6-fold. A numerical comparison demonstrated that the results from the rule-out approach are similar to that of the E-value approach when there is a lack of prior data on bias parameters.

CONCLUSIONS

Using three different approaches, we demonstrate that the strengths of association between smoking and both FQ and AA need to be unusually strong to fully account for the twofold increased risk between FQ and AA. Therefore, it is unlikely that smoking alone would explain away the association reported in the epidemiologic studies.

Pathogenic mechanisms and the potential of drug therapies for aortic aneurysm

Aortic aneurysm is a permanent focal dilation of the aorta. It is usually an asymptomatic disease but can lead to sudden death due to aortic rupture. Aortic aneurysm-related mortalities are estimated at ∼200,000 deaths per year worldwide. Because no pharmacological treatment has been found to be effective so far, surgical repair remains the only treatment for aortic aneurysm. Aortic aneurysm results from changes in the aortic wall structure due to loss of smooth muscle cells and degradation of the extracellular matrix and can form in different regions of the aorta. Research over the past decade has identified novel contributors to aneurysm formation and progression. The present review provides an overview of cellular and noncellular factors as well as enzymes that process extracellular matrix and regulate cellular functions (e.g., matrix metalloproteinases, granzymes, and cathepsins) in the context of aneurysm pathogenesis. An update of clinical trials focusing on therapeutic strategies to slow abdominal aortic aneurysm growth and efforts underway to develop effective pharmacological treatments is also provided.

Blood pressure, hypertension and the risk of abdominal aortic aneurysms: a systematic review and meta-analysis of cohort studies

Abdominal aortic aneurysms (AAA) are fatal in 80% of the cases when ruptured. Hypertension has been considered a potential risk factor for AAA; but the findings from prospective cohort studies have not been entirely consistent, nor have they been summarised in a comprehensive meta-analysis. Our aim was to conduct a systematic review and meta-analysis of cohort studies of the association between blood pressure, hypertension and AAA to clarify the strength and shape of these associations. We searched PubMed and Embase databases for relevant cohort studies up to April 30th, 2018. Random-effects models were used to calculate summary relative risks (RRs) and 95% confidence intervals (CIs). The meta-analysis included 21 cohort studies (20 publications) with data on 28,162 cases and 5,440,588 participants. The findings indicate that the RR of AAA in hypertensive patients is 1.66 times (95% CI: 1.49–1.85, I² = 79.3%, n = 13) that of non-hypertensive patients. In addition, there was a 14% (95% CI: 6–23%, I² = 30.5%, n = 6) and a 28% (95% CI: 12–46%, I² = 80.1%, n = 6) increase in the RR of AAA for every 20 mmHg and 10 mmHg increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. The analysis of DBP showed evidence of a strong and highly significant nonlinear dose–response relationship (p < 0.001) with a steeper association from 80 mmHg and above. This meta-analysis suggests that hypertension increases the risk of developing AAA by 66%. Further studies are needed to clarify the underlying mechanism explaining the much stronger association between DBP and AAA than for SBP.

Diabetes mellitus and the risk of abdominal aortic aneurysm: A systematic review and meta-analysis of prospective studies

BACKGROUND

Diabetes mellitus has been associated with reduced risk of abdominal aortic aneurysm in a number of epidemiological studies, however, until recently little data from prospective studies have been available. We therefore conducted a systematic review and meta-analysis of prospective studies to quantify the association.

MATERIAL AND METHODS

Two investigators searched the PubMed and Embase databases for studies of diabetes and abdominal aortic aneurysm up to May 8th 2018. Prospective studies were included if they reported adjusted relative risk (RR) estimates and 95% confidence intervals (95% CIs) of abdominal aortic aneurysm associated with a diabetes diagnosis. Summary relative risks were estimated by use of a random effects model.

RESULTS

We identified 16 prospective studies with 16,572 cases among 4,563,415 participants that could be included in the meta-analysis. The summary RR for individuals with diabetes compared to individuals without diabetes was 0.58 (95% CI: 0.51-0.66, I² = 40.4%, p_{heterogeneity} = 0.06). The results persisted when stratified by sex, duration of follow-up, and in most of the other subgroup analyses. There was no evidence of publication bias with Egger's test, p = 0.64 or by inspection of the funnel plots.

CONCLUSIONS

These results suggest that individuals with diabetes mellitus are at a reduced risk of abdominal aortic aneurysm, however, whether pharmacological agents for diabetes mellitus explain this observation needs to be clarified in future studies.

Tobacco smoking and the risk of abdominal aortic aneurysm: a systematic review and meta-analysis of prospective studies

Several studies have found that smoking increases the risk of abdominal aortic aneurysm, however, the strength of the association has differed between studies and data from cohort studies have not yet been summarized. A systematic review and meta-analysis was therefore conducted to clarify this association. We searched PubMed and Embase databases up to May 2nd 2018. A random effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). Twenty three prospective studies were included. Comparing current, former and ever smokers with never smokers the summary RRs were 4.87 (95% CI: 3.93-6.02, I2 = 92%, n = 20), 2.10 (95% CI: 1.76-2.50, I2 = 71%, n = 15) and 3.28 (95% CI: 2.60-4.15, I2 = 96%, n = 18), respectively. The summary RR was 1.87 (95% CI: 1.45-2.40, I2 = 97%) per 10 cigarettes per day, 1.78 (95% CI: 1.54-2.06, I2 = 83%) per 10 pack-years was and 0.45 (95% CI: 0.32-0.63, I2 = 92.3%) per 10 years of smoking cessation. There was evidence of nonlinearity for cigarettes per day and pack-years (pnonlinearity < 0.0001 and pnonlinearity = 0.02, respectively), but not for smoking cessation, pnonlinearity = 0.85. Among smokers who quit, the RR was similar to that of never smokers by 25 years of smoking cessation. These findings confirm a strong association between smoking and the risk of developing abdominal aortic aneurysms.

Meta-analysis of the association between alcohol consumption and abdominal aortic aneurysm

Background

Alcohol is a possible risk factor for abdominal aortic aneurysm (AAA), but evidence from individual studies is weak and inconsistent. Existing narrative reviews suggest the possibility of non-linear associations. The aim here was to quantify any association using a systematic literature review, followed by dose–response meta-analysis of prospective studies.

Methods

MEDLINE, Embase and Web of Science were searched systematically to January 2017 for relevant prospective studies of alcohol consumption and AAA risk. Summary estimates of highest versus lowest levels of consumption, and linear and non-linear dose–response curves were quantified using random-effects models.

Results

Eleven relevant cohorts were identified describing results from 3580 individuals with among 473 092 participants. Data were extracted from ten cohorts for meta-analyses of high versus low levels of alcohol consumption (risk ratio for AAA 0·93, 95 per cent c.i. 0·78 to 1·11; P = 0·4, I2 = 47 per cent). The linear dose–response risk ratio for AAA, derived from 11 cohorts, was 1·00 (0·97 to 1·04) per 8 g alcohol per day (P = 0·9, I2 = 73 per cent). Non-linear dose–response results showed a tick-shaped curve with lower risk up to 2 units/day, but increasing risk beyond that (P = 0·05). The increase in risk beyond 2 units/day was stronger in men than in women.

Conclusion

Although the linear dose–response analysis revealed little evidence of an association between alcohol consumption and AAA risk, a tick-shaped trend in the association was observed. This non-linear dose–response analysis revealed reduced risks for alcohol consumption below 2 units/day, masking increased risks for 2 or more units/day.

[Ultrasound screening of abdominal aortic aneurysm: Lessons from Vesale 2013]

Although aneurysm of the abdominal infra-renal aorta (AAA) meets criteria warranting B mode ultrasound screening, the advantages of mass screening versus selective targeted opportunistic screening remain a subject of debate. In France, the French Society of Vascular Medicine (SFMV) and the Health Authority (HAS) published recommendations for targeted opportunistic screening in 2006 and 2013 respectively. The SFMV held a mainstream communication day on November 21, 2013 in France involving participants from metropolitan France and overseas departments that led to a proposal for free AAA ultrasound screening: the Vesalius operation. Being a consumer operation, the selection criteria were limited to age (men and women between 60 and 75 years); the age limit was lowered to 50 years in case of direct family history of AAA. More than 7000 people (as many women as men) were screened in 83 centers with a 1.70% prevalence of AAA in the age-based target population (3.12% for men, 0.27% for women). The median diameter of detected AAA was 33 mm (range 20 to 74 mm). The prevalence of AAA was 1.7% in this population. Vesalius data are consistent with those of the literature both in terms of prevalence and for cardiovascular risk factors with the important role of smoking. Lessons from Vesalius to take into consideration are: screening is warranted in men 60 years and over, especially smokers, and in female smokers. Screening beyond 75 years should be discussed. Given the importance of screening, the SFMV set up a year of national screening for AAA (Vesalius operation 2014/2015) in order to increase public and physician awareness about AAA detection, therapeutic management, and monitoring. AAA is a serious, common, disease that kills 6000 people each year. The goal of screening is cost-effective reduction in the death toll.

Population-Based Study of Incidence of Acute Abdominal Aortic Aneurysms With Projected Impact of Screening Strategy

BACKGROUND

Current abdominal aortic aneurysm (AAA) screening in men age 65 might have limited impact on overall AAA death rates if incidence is moving to older ages. Up-to-date population-based studies of age-specific incidence, risk factors, and outcome of acute AAA are needed to inform screening policy.

METHODS AND RESULTS

In a prospective, population-based study (Oxfordshire, UK, 2002-2014), the incidence and outcome of acute AAA events were determined. Based on population projections and current incidence trends, the impact of screening strategies in the UK was estimated. Over the 12-year period, 103 incident acute AAA events occurred in the study population of 92 728. Incidence/100 000/year was 55 in men ages 65 to 74 years, but increased to 112 at 75 to 85 and 298 at ≥85, with 66.0% of all events occurring at age ≥75 years. Incidence at ages 65 to 74 was highest in male smokers (274), with 96.4% of events in men <75 years occurring in ever-smokers. Extrapolating rates to the UK population, using trial evidence of screening efficacy, the current UK screening program would prevent 5.6% of aneurysm-related deaths (315 200 scans/year: 1426/death prevented, 121/year-of-life saved). Screening only male smokers age 65 and then all men at age 75 would prevent 21.1% of deaths (247 900 scans/year; 297/death prevented, 34/year-of-life saved). By 2030, 91.0% of deaths will occur at age ≥75, 61.6% at ≥85, and 28.6% in women.

CONCLUSIONS

Given that two thirds of acute AAA occurred at ≥75 years of age, screening older age groups should be considered. Screening nonsmokers at age 65 is likely to have very little impact on AAA event rates.

Age-specific incidence, risk factors and outcome of acute abdominal aortic aneurysms in a defined population

BACKGROUND

Contemporary population-based data on age-specific incidence and outcome from acute abdominal aortic aneurysm (AAA) events are needed to understand the impact of risk factor modification and demographic change, and to inform AAA screening policy.

METHODS

In a prospective population-based study (Oxfordshire, UK, 2002-2014), event rates, incidence, early case fatality and long-term outcome from all acute AAA events were determined, both overall and in relation to the four main risk factors: smoking, hypertension, male sex and age.

RESULTS

Over the 12-year interval, 103 incident acute AAA events occurred in the study population of 92,728 (men 72·8 per cent; 59·2 per cent 30-day case fatality rate). The incidence per 100,000 population per year was 55 in men aged 65-74 years, but increased to 112 at age 75-84 years and to 298 at age 85 years or above. Some 66·0 per cent of all events occurred in those aged 75 years or more. The incidence at 65-74 years was highest in male smokers (274 per 100,000 population per year); 27 (96 per cent) of 28 events in men aged less than 75 years occurred in ever-smokers. Mean(s.d.) age at event was lowest in current smokers (72·2(7·2) years), compared with that in ex-smokers (81·2(7·0) years) and never-smokers (83·3(7·9) years) (P < 0·001). Hypertension was the predominant risk factor in women (diagnosed in 93 per cent), with 20 (71 per cent) of all 28 events in women occurring in those aged 75 years or above with hypertension. The 30-day case fatality rate increased from 40 per cent at age below 75 years to 69 per cent at age 75 years or more (P = 0·008).

CONCLUSION

Two-thirds of acute AAA events occurred at age 75 years or above, and more than 25 per cent of events were in women. Taken with the strong associations with smoking and hypertension, these findings could have implications for AAA screening.

A comprehensive analysis of differentially expressed genes and pathways in abdominal aortic aneurysm

The current study aimed to investigate the molecular mechanism underlying abdominal aortic aneurysm (AAA) via various bioinformatics techniques. Gene expression profiling analysis of differentially expressed genes (DEGs) between AAA samples and normal controls was conducted. The Database for Annotation, Visualization and Integrated Discovery tool was utilized to perform Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses for DEGs and clusters from the protein-protein interaction (PPI) network, which was constructed using the Search Tool for the Retrieval of Interacting Genes. In addition, important transcription factors (TFs) that regulated DEGs were investigated. A total of 346 DEGs were identified between AAA samples and healthy controls. Additionally, four clusters were identified from the PPI network. Cluster 1 was associated with sensory perception of smell and the olfactory transduction subpathway. The most significant GO function terms for cluster 2 and 3 were response to virus and defense response, respectively. Cluster 4 was associated with mitochondria-associated functions and the oxidative phosphorylation subpathway. Early growth response-1 (EGR-1), Myc, activating transcription factor 5 (ATF5) and specificity protein (SP) 1:SP3 were identified to be critical TFs in this disease. The present study suggested that the olfactory transduction subpathway, mitochondria and oxidative phosphorylation pathways were involved in AAA, and TFs, such as EGR-1, Myc, ATF5 and SP1:SP3, may be potential candidate molecular targets for this disease.

A propensity score-matching analysis of transthoracic echocardiography and abdominal ultrasonography for the detection of abdominal aortic aneurysms

INTRODUCTION

We previously reported that the prevalence of abdominal aortic aneurysms (AAAs) was higher in patients undergoing scheduled transthoracic echocardiography (TTE) than in patients undergoing abdominal ultrasonography (AUS); however, intergroup patient backgrounds differed significantly in that report.

PURPOSE

We tested the hypothesis that TTE could detect AAA as effectively as AUS.

DESIGN

A propensity score-matching analysis of a cross-sectional study was adopted as the design for this study.

METHODS

We enrolled 7,619 and 15,433 patients scheduled to undergo TTE with additional evaluation of abdominal aorta at the end of the routine study and AUS, respectively, from 2009 to 2010 in our hospital, as reported. A propensity score for profiles of patients who underwent TTE or AUS was developed to adjust for potential confounding bias. Consequently, 4,388 patients in each group were matched for analyses.

RESULTS

In propensity-matched patients, AAA was detected in 59 patients of the TTE group and in 48 patients of the AUS group; the prevalence of AAA detection did not differ significantly between TTE and AUS groups (P = 0.331). Positive associations were observed between AAA detection and male sex (adjusted odds ratio [OR]: 3.25; 95% confidence interval [CI], 2.05–5.15; P < 0.001), older age (adjusted OR: 1.029; 95% CI: 1.01–1.04; P < 0.001), and the presence of ischemic heart disease (adjusted OR: 1.78; 95% CI: 1.04–3.03; P = 0.033) and hypertension (adjusted OR: 2.16; 95% CI: 1.38–3.37; P = 001).

CONCLUSION

TTE detected AAA with comparable efficacy as AUS in propensity-matched groups who underwent scheduled TTE and AUS.

Aneurysm global epidemiology study: public health measures can further reduce abdominal aortic aneurysm mortality

BACKGROUND

Contemporary data from Western populations suggest steep declines in abdominal aortic aneurysm (AAA) mortality; however, international trends are unclear. This study aimed to investigate global AAA mortality trends and to analyze any association with common cardiovascular risk factors.

METHODS AND RESULTS

AAA mortality (1994-2010) using International Classification of Diseases codes were extracted from the World Health Organization mortality database and age standardized. The World Health Organization InfoBase and International Mortality and Smoking Statistics provided risk factor data. Nineteen World Health Organization member states were included (Europe, 14; Australasia, 2; North America, 2; Asia, 1). Regression analysis of temporal trends in cardiovascular risk factors (1946-2010) was done independently for correlations to AAA mortality trends. Global AAA mortality trends show substantial heterogeneity, with the United States and United Kingdom recording the greatest national decline, whereas internationally, male individuals and those <75 years of age demonstrated the greatest reductions. AAA mortality has increased in Hungary, Romania, Austria, and Denmark; therefore, the mortality decline is not universal. A positive linear relationship exists between global trends in systolic blood pressure (P≤0.03), cholesterol (P≤0.03), and smoking prevalence (P≤0.02) in males and females. Body mass index demonstrated a negative linear association with AAA mortality (P≤0.007), whereas fasting blood glucose showed no association.

CONCLUSIONS

AAA mortality has not declined globally, and this study reveals that differences between nations can be explained by variations in traditional cardiovascular risk factors. Declines in smoking prevalence correlate most closely with declines in AAA mortality, and a novel obesity paradox has been identified that requires further investigation. Public health measures could therefore further reduce global AAA mortality, with greatest benefits in the younger age group.

The relative risk of aortic aneurysm in patients with giant cell arteritis compared with the general population of the UK

OBJECTIVES

To evaluate the risk of aortic aneurysm in patients with giant cell arteritis (GCA) compared with age-, gender- and location-matched controls.

METHODS

A UK General Practice Research Database (GPRD) parallel cohort study of 6999 patients with GCA and 41 994 controls, matched on location, age and gender, was carried out. A competing risk model using aortic aneurysm as the primary outcome and non-aortic-aneurysm-related death as the competing risk was used to determine the relative risk (subhazard ratio) between non-GCA and GCA subjects, after adjustment for cardiovascular risk factors.

RESULTS

Comparing the GCA cohort with the non-GCA cohort, the adjusted subhazard ratio (95% CI) for aortic aneurysm was 1.92 (1.52 to 2.41). Significant predictors of aortic aneurysm were being an ex-smoker (2.64 (2.03 to 3.43)) or a current smoker (3.37 (2.61 to 4.37)), previously taking antihypertensive drugs (1.57 (1.23 to 2.01)) and a history of diabetes (0.32 (0.19 to 0.56)) or cardiovascular disease (1.98 (1.50 to 2.63)). In a multivariate model of the GCA cohort, male gender (2.10 (1.38 to 3.19)), ex-smoker (2.20 (1.22 to 3.98)), current smoker (3.79 (2.20 to 6.53)), previous antihypertensive drugs (1.62 (1.00 to 2.61)) and diabetes (0.19 (0.05 to 0.77)) were significant predictors of aortic aneurysm.

CONCLUSIONS

Patients with GCA have a twofold increased risk of aortic aneurysm, and this should be considered within the range of other risk factors including male gender, age and smoking. A separate screening programme is not indicated. The protective effect of diabetes in the development of aortic aneurysms in patients with GCA is also demonstrated.