Understanding the effects of tobacco smoke on the pathogenesis of aortic aneurysm

Causal relationship between immune cells and aortic aneurysms: a Mendelian randomization study

OBJECTIVES

The causal association between immune cell traits and aortic aneurysm remains unknown.

METHODS

We performed a bidirectional two-sample Mendelian randomization analysis to explore the causality between 731 immune cell characteristics and the risk of abdominal aortic aneurysm and thoracic aortic aneurysms through publicly available genetic data, respectively. To examine heterogeneity and horizontal pleiotropy, Cochran's Q test and MR-Egger intercept were utilized. Additionally, multivariable Mendelian randomization analysis and meta-analysis were performed in further analysis.

RESULTS

We found that 20 immune phenotypes had a suggestive causality on abdominal aortic aneurysm, and 15 immune phenotypes had a suggestive causal effect on thoracic aortic aneurysm. After further false discovery rate adjustment (q value <0.1), CD20 on IgD+ CD38- B cell (q = 0.053) and CD127 on CD28+ CD4+ T cell (q = 0.096) were associated with an increased risk of abdominal aortic aneurysm, respectively, indicating a significant causality between them. After adjusting for smoking, there is still statistical significance between CD127 on CD28+ CD4+ T cell and abdominal aortic aneurysm. However, after adjusting for lipids, no statistical significance can be observed between CD127 on CD28+ CD4+ T cells and abdominal aortic aneurysm. Furthermore, there is still statistical significance between CD20 on IgD+ CD38- B cells and abdominal aortic aneurysm after adjusting for lipids and smoking, which was further identified by meta-analysis.

CONCLUSIONS

We found a causal association between immune cell traits and aortic aneurysm by genetic methods, thus providing new avenues for future mechanism studies.

Sex disparities in popliteal artery aneurysms

OBJECTIVE

Only 5% of patients with popliteal artery aneurysms (PAAs) are female. Evidence on PAA treatment and outcomes in women is therefore scarce. The POPART Registry provides one of Europe's largest data collections regarding PAA treatment. Data on clinical presentation, aneurysm morphology, and perioperative outcomes after open surgical PAA repair in women will be presented.

METHODS

POPART is a multicenter, noninterventional registry for open and endovascular PAA repair, with 42 participating centers in Germany and Luxembourg. All patients aged >18 years who have been treated for PAA since 2010 are eligible for study inclusion. Data collection is based on an online electronic case report form.

RESULTS

Of the 1236 PAAs, 58 (4.8%) were in women. There were no significant differences in age or cardiopulmonary comorbidities. However, female patients had a lower prevalence of contralateral PAAs and abdominal aortic aneurysms (P < .05). PAAs in women were more likely to be symptomatic before surgery (65.5% vs 49.4%; P = .017), with 19% of women presenting with acute limb ischemia (vs 11%; P = .067). Women had smaller aneurysm diameters than men (22.5 mm vs 27 mm; P = .004) and became symptomatic at smaller diameters (20 mm vs 26 mm; P = .002). Only 8.6% of women and 11.6% of men underwent endovascular aneurysm repair (P > .05); therefore, the perioperative outcome analysis focused on open surgical repair. In total, 23.5% of women and 16.9% of men developed perioperative complications (P > .05). There were no differences in major cardiovascular events (P > .05), but women showed a higher incidence of impaired wound healing (15.7% vs 7.2%; P = .05) and major amputation (5.9% vs 1.1%; P = .027). Female sex was significantly associated with the need for nonvascular reinterventions within 30 days after surgery (odds ratio: 2.48, 95% confidence interval: 1.26-4.88), whereas no significant differences in the odds for vascular reinterventions were observed (odds ratio: 1.98, 95% confidence interval: 0.68-5.77). In the multiple logistic regression model, female sex, symptomatic PAAs, poor quality of outflow vessels, and graft material other than vein graft were independently associated with perioperative reinterventions.

CONCLUSIONS

Women have smaller PAAs, are more likely to be symptomatic before treatment, and are more often affected by nonvascular reinterventions in the perioperative course. As our understanding of aneurysmatic diseases in women continues to expand, sex-specific treatment strategies and screening options for women in well-selected cohorts with modified screening protocols should be continuously re-evaluated.

Global burden of cardiovascular disease attributable to smoking, 1990-2019: an analysis of the 2019 Global Burden of Disease Study

AIMS

This study aims to investigate the trends in the global cardiovascular disease (CVD) burden attributable to smoking from 1990 to 2019.

METHODS AND RESULTS

Global Burden of Disease Study 2019 was used to analyse the burden of CVD attributable to smoking (i.e. ischaemic heart disease, peripheral artery disease, stroke, atrial fibrillation and flutter, and aortic aneurysm). Age-standardized mortality rates (ASMRs) per 100 000 and age-standardized disability-adjusted life year rates (ASDRs) per 100 000, as well as an estimated annual percentage change (EAPC) in ASMR and ASDR, were determined by age, sex, year, socio-demographic index (SDI), regions, and countries or territories. The global ASMR of smoking-attributed CVD decreased from 57.16/100 000 [95% uncertainty interval (UI) 54.46-59.97] in 1990 to 33.03/100 000 (95% UI 30.43-35.51) in 2019 [EAPC -0.42 (95% UI -0.47 to -0.38)]. Similarly, the ASDR of smoking-attributed CVD decreased between 1990 and 2019. All CVD subcategories showed a decline in death burden between 1990 and 2019. The burden of smoking-attributed CVD was higher in men than in women. Significant geographic and regional variations existed such that Eastern Europe had the highest ASMR and Andean Latin America had the lowest ASMR in 2019. In 2019, the ASMR of smoking-attributed CVD was lowest in high SDI regions.

CONCLUSION

Smoking-attributed CVD morbidity and mortality are declining globally, but significant variation persists, indicating a need for targeted interventions to reduce smoking-related CVD burden.

Trends in Abdominal Aortic Aneurysm Repair Incidence, Comorbidity, Treatment, and Mortality: A Danish Nationwide Cohort Study, 1996-2018

Background

Significant changes in Western populations' abdominal aortic aneurysm (AAA) epidemiology have been reported following the introduction of screening, endovascular AAA repair, and reduced tobacco consumption. We report incidence and mortality of AAA repair in Denmark from 1996 to 2018, where AAA screening was not implemented.

Methods

Nationwide cohort study of prospective data from population-based Danish registries covering 1996 to 2018. We identified 15,395 patients undergoing first-time AAA repair using the Danish Vascular Registry. Comorbidity was assessed by Charlson's Comorbidity Index (CCI). Incidence rate (IR) ratios and mortality rate ratios (MRR) were estimated by multivariable Poisson and Cox regression, respectively.

Results

Overall AAA repair IR decreased by 24% from 1996 through 2018, mainly reflecting a 53% IR reduction in ruptured AAA repairs in men. Overall, the IR decreased 52-63% in age groups below 70 years and increased 81% among octogenarians. The proportion of intact AAAs repaired endovascularly increased from 2% in 1996-1999 to 42% in 2015-2018. For both ruptured and intact AAAs the CCI score increased by 0.9% annually independently of age and sex. The adjusted five-year MRR in 2016-2018 vs.1996-2000 was 0.46 (95% confidence interval (CI): 0.39-0.54) following ruptured and 0.51 (95% CI: 0.44-0.59) following intact AAA repair.

Conclusion

In Denmark, overall AAA repair incidence decreased between 1996 and 2018, primarily reflecting a reduction among males and a shift to an older population requiring intervention. These trends mirror changes in tobacco consumption in Denmark. Regardless of age and comorbidity, AAA repair mortality decreased markedly during the study period.

Antiplatelet Therapy, Abdominal Aortic Aneurysm Progression, and Clinical Outcomes

Importance

Preclinical studies suggest a potential role for aspirin in slowing abdominal aortic aneurysm (AAA) progression and preventing rupture. Evidence on the clinical benefit of aspirin in AAA from human studies is lacking.

Objective

To investigate the association of aspirin use with aneurysm progression and long-term clinical outcomes in patients with AAA.

Design, Setting, and Participants

This was a retrospective, single-center cohort study. Adult patients with at least 2 available vascular ultrasounds at the Cleveland Clinic were included, and patients with history of aneurysm repair, dissection, or rupture were excluded. All patients were followed up for 10 years. Data were analyzed from May 2022 to July 2023.

Main Outcomes and Measures

Clinical outcomes were time-to-first occurrence of all-cause mortality, major bleeding, or composite of dissection, rupture, and repair. Multivariable-adjusted Cox proportional-hazard regression was used to estimate hazard ratios (HR) for all-cause mortality, and subhazard ratios competing-risk regression using Fine and Gray proportional subhazards regression was used for major bleeding and composite outcome. Aneurysm progression was assessed by comparing the mean annualized change of aneurysm diameter using multivariable-adjusted linear regression and comparing the odds of having rapid progression (annual diameter change >0.5 cm per year) using logistic regression.

Results

A total of 3435 patients (mean [SD] age 73.7 [9.0] years; 2672 male patients [77.5%]; 120 Asian, Hispanic, American Indian, or Pacific Islander patients [3.4%]; 255 Black patients [7.4%]; 3060 White patients [89.0%]; and median [IQR] follow-up, 4.9 [2.5-7.5] years) were included in the final analyses, of which 2150 (63%) were verified to be taking aspirin by prescription. Patients taking aspirin had a slower mean (SD) annualized change in aneurysm diameter (2.8 [3.0] vs 3.8 [4.2] mm per year; P = .001) and lower odds of having rapid aneurysm progression compared with patients not taking aspirin (adjusted odds ratio, 0.64; 95% CI, 0.49-0.89; P = .002). Aspirin use was not associated with risk of all-cause mortality (adjusted HR [aHR], 0.92; 95% CI, 0.79-1.07; P = .32), nor was aspirin use associated with major bleeding (aHR, 0.88; 95% CI, 0.76-1.03; P = .12), or composite outcome (aHR, 1.16; 95% CI, 0.93-1.45; P = .09) at 10 years.

Conclusions

In this retrospective study of a clinical cohort of 3435 patients with objectively measured changes in aortic aneurysm growth, aspirin use was significantly associated with slower progression of AAA with a favorable safety profile.

Cigarette Smoking and Intracranial Aneurysms: A Pilot Analysis of SNPs in the CYP2A6 Gene in the Italian Population

BACKGROUND

Cigarette smoking is a modifiable risk factor associated with formation and rupture of intracranial aneurysms (IAs). Cytochrome P450 2A6 (CYP2A6) is the main enzyme implied in catabolism of nicotine and xenobiotics, giving rise to oxidative stress products. Our study investigated the associations between specific single-nucleotide polymorphisms (SNPs) in the CYP2A6 gene and the presence of sporadic IAs in a cluster of Italian patients, as well as their rupture regarding cigarette smoking habit.

METHODS

Three hundred and thirty-one Italian patients with sporadic IAs were recruited in a single institution. We recorded data on clinical onset with subarachnoid hemorrhage (SAH) and smoking habit. Genetic analysis was performed with a standard procedure on peripheral blood samples: CYP2A6 ∗1B2, CYP2A6 ∗2, and CYP2A6 ∗14 SNPs were analyzed in the study group along with 150 healthy control subjects. Statistical analysis was conducted according to genetic association study guidelines.

RESULTS

In the patient cohort, the frequency of aSAH was significantly higher in current smokers (P < 0.001; OR=17.45), regardless of the pattern of CYP2A6 SNPs. There was a correlation between IA rupture and cigarette smoking in patients with the heterozygous CYP2A6 ∗1B2 allele (P < 0.001; OR=15.47). All patients carrying the heterozygous CYP2A6 ∗14 allele had an aSAH event (100%), regardless of smoking habit, although this correlation was not statistically significant (P = 1).

CONCLUSIONS

According to our findings, a cigarette smoker carrying a fully active CYP2A6 enzyme (heterozygous ∗1B2 allele) may have an increased risk of IA rupture compared to those with functionally less active variants: further investigation on a larger sample is needed to verify this result. The role of the heterozygous CYP2A6 ∗14 allele in aSAH is yet to be clarified.

Clinical analysis of 908 patients with aortic dissection under different Stanford types: A cross-sectional study

This study aims to investigate the difference of clinical characteristics and risk factors in aortic dissection (AD) of patients with 2 Stanford subtypes. A retrospective analysis was conducted on 908 patients admitted to Tongji Hospital from July 2019 to January 2021, and the aortic computed tomography angiography was used to clearly diagnose the artery dissection. Patient basic information as well as blood test indicators containing leukocytes, neutrophils, lymphocytes, hemoglobin, myoglobin, hypersensitive cardiac troponin, γ-glutamyl transferase, total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein, ultrasensitive C-reactive protein, glucose were recorded and analyzed. There was no significant difference in gender, heart rate, smoking history, hypertension history and diabetes history between the 2 groups (P > .05), however, compared with type A patients, type B patients were older, and had a significantly higher frequency of alcohol consumption (P < .05); On laboratory tests, type A patients had significantly higher mean leukocytes and neutrophils (P < .05), and significantly lower frequency of reduced hemoglobin than type B patients (P < .05), although there was no statistical difference in lymphocyte, γ-glutamyl transferase, total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein and glucose counts between the 2 groups. Additionally, type A patients had a significantly higher number of abnormal myoglobin, hypersensitive cardiac troponin and ultrasensitive C-reactive protein test results than type B patients (P < .05). The receiver operating characteristic curve analysis showed that the area under the curve for each parameter was 0.605 (0.538-0.673) for hemoglobin, 0.610 (0.543-0.677) for leukocytes and 0.627 (0.561-0.693) for neutrophils. Understanding the relevant clinical indicators and risk factors of patients with different types of AD can provide a new perspective to assist the classification and diagnosis of AD and a basis for effective and rational treatment.

The Global and Regional Prevalence of Abdominal Aortic Aneurysms: A Systematic Review and Modeling Analysis

OBJECTIVE

To estimate the global and regional prevalence and cases of abdominal aortic aneurysms (AAAs) in 2019 and to evaluate major associated factors.

BACKGROUND

Understanding the global prevalence of AAA is essential for optimizing health services and reducing mortality from reputed AAA.

METHODS

PubMed, MEDLINE, and Embase were searched for articles published until October 11, 2021. Population-based studies that reported AAA prevalence in the general population, defined AAA as an aortic diameter of 30 mm or greater with ultrasonography or computed tomography. A multilevel mixed-effects meta-regression approach was used to establish the relation between age and AAA prevalence for high-demographic sociodemographic index and low-and middle-sociodemographic index countries. Odds ratios of AAA associated factors were pooled using a random-effects method.

RESULTS

We retained 54 articles across 19 countries. The global prevalence of AAA among persons aged 30 to 79 years was 0.92% (95% CI, 0.65-1.30), translating to a total of 35.12 million (95% CI, 24.94-49.80) AAA cases in 2019. Smoking, male sex, family history of AAA, advanced age, hypertension, hypercholesterolemia, obesity, cardiovascular disease, cerebrovascular disease, claudication, peripheral artery disease, pulmonary disease, and renal disease were associated with AAA. In 2019, the Western Pacific region had the highest AAA prevalence at 1.31% (95% CI, 0.94-1.85), whereas the African region had the lowest prevalence at 0.33% (95% CI, 0.23-0.48).

CONCLUSIONS

A substantial proportion of people are affected by AAA. There is a need to optimize epidemiological studies to promptly respond to at-risk and identified cases to improve outcomes.

Abdominal aortic aneurysm presenting to the orthopedic clinic as posterior hip and low back pain

Abdominal aortic aneurysms (AAAs) are typically asymptomatic. When symptomatic, AAA may present as a chief concern of musculoskeletal hip and low back pain. Assessment in the orthopedic clinic should focus on a holistic examination of the patient.

E-cigarette exposure augments murine abdominal aortic aneurysm development: role of Chil1

AIMS

Abdominal aortic aneurysm (AAA) is a common cardiovascular disease with a strong correlation to smoking, although underlying mechanisms have been minimally explored. Electronic cigarettes (e-cigs) have gained recent broad popularity and can deliver nicotine at comparable levels to tobacco cigarettes, but effects on AAA development are unknown.

METHODS AND RESULTS

We evaluated the impact of daily e-cig vaping with nicotine on AAA using two complementary murine models and found that exposure enhanced aneurysm development in both models and genders. E-cigs induced changes in key mediators of AAA development including cytokine chitinase-3-like protein 1 (CHI3L1/Chil1) and its targeting microRNA-24 (miR-24). We show that nicotine triggers inflammatory signalling and reactive oxygen species while modulating miR-24 and CHI3L1/Chil1 in vitro and that Chil1 is crucial to e-cig-augmented aneurysm formation using a knockout model.

CONCLUSIONS

In conclusion our work shows increased aneurysm formation along with augmented vascular inflammation in response to e-cig exposure with nicotine. Further, we identify Chil1 as a key mediator in this context. Our data raise concerns regarding the potentially harmful long-term effects of e-cig nicotine vaping.

Dying to Get There: Patients Who Reside at Increased Distance from Tertiary Center Experience Increased Mortality Following Abdominal Aortic Aneurysm Rupture

BACKGROUND

Centralization of vascular surgery care for Ruptured Abdominal Aortic Aneurysms (RAAAs) to high-volume tertiary centers may hinder access to timely surgical intervention for patients in remote areas. The objective of this study was to determine the association between distance from vascular care and mortality from RAAAs in the province of Nova Scotia, Canada.

METHODS

A retrospective cohort study of all RAAAs in Nova Scotia between 2005 and 2015 was performed through linkage of administrative databases. Patients were divided into groups by estimated travel time from their place of residence to the tertiary center (<1 hr and ≥1 hr) using geographic information software. Baseline and operative characteristics were identified for all patients through available databases and completed through chart review. Mortality at home, during transfer to the vascular center, and overall 30-day mortality were compared between groups using t-test and chi-squared test, as appropriate. Multivariable logistic regression analysis was used to calculate the independent effect of travel time on survival outcomes.

RESULTS

A total of 567 patients with RAAA were identified from 2005-2015, of which 250 (44%) resided <1 hr travel time to the tertiary center and 317 (56%) resided ≥1 hr. On multivariable analysis, travel time ≥1 hr from vascular care was an independent predictor of mortality at home (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.07-2.63, P = 0.02), mortality prior to operation (OR 2.64, 95% CI 1.81-3.83, P < 0.001), and overall 30-day mortality (OR 1.61, 95% CI 1.10-2.37, P = 0.02). In patients who received an operation (n = 294), there was no association between increased travel time and mortality (OR 1.02, 95% CI 0.60-1.73, P = 0.94).

CONCLUSIONS

Travel time ≥1 hr to the tertiary center is associated with significantly higher mortality from ruptured abdominal aortic aneurysm (AAA). However, there was no difference in overall chance of survival between groups for patients that underwent AAA repair. Therefore, strategies to facilitate early detection, and timely transfer to a vascular surgery center may improve outcomes for patients with RAAA.

Management of aortic occlusion in a morbidly obese smoker: A case report

Total occlusion of the abdominal aorta is a rare and life-threatening event. Risk factors most commonly include coagulopathy, vasculitis, trauma, abdominal aortic aneurysms, aortic thromboembolism, and aortic dissection. The most common complications include severe ischemic manifestations in the lower extremities, spinal cord, or viscera. Thus, management is largely dependent on presumed etiology. We present a case of a morbidly obese 52-year-old female with a past medical history of hypertension, diabetes mellitus, peripheral vascular disease, and coronary artery disease with a smoking history of three packs per day for over 10 years. The patient first presented to our emergency department with bilateral lower extremity paresthesia and pain at rest. Further evaluation through computed tomography angiogram thus revealed infrarenal occlusion of the abdominal aorta and bilateral common iliac arteries; the patient was treated with an aorto-femoral bypass without further sequelae. Our case report details the associated risk factors of acute on chronic aortic occlusion and its management.

Abdominal aortic aneurysm and exfoliation syndrome in Utah

PURPOSE

A pilot study of electronic medical records (EMR) in Utah was undertaken to investigate exfoliation syndrome and exfoliation glaucoma (XFS/XFG) in abdominal aortic aneurysm (AAA) patients. In a subsequent retrospective cohort study of Utah XFS/XFG patients and population controls, the risk of AAA was examined.

METHODS

EMR of a statewide healthcare population were obtained from the Utah Population Database (UPDB) which links decades of medical records with Utah demographic and vital records data. In a pilot study, 7167 patients ages ≥40 years identified with AAA diagnosed from 1996 to 2015, based on International Classification of Diseases (ICD) version 9/10 codes, were included. A univariable hazards model was used to determine the risk of XFS/XFG in AAA patients. An XFS/XFG outcome based on ICD 9/10 codes in AAA patients and in 5:1 sex- and age-matched non-AAA controls was determined. A retrospective cohort of 3412 XFS/XFG patients ages ≥50 years diagnosed from 1996 to 2020 and 10 227 3:1 sex- and age-matched controls who underwent ≥1 dilated eye examination(s) were recently identified and updated diagnoses of AAA were obtained. Multivariable logistic regression was used to estimate AAA risk in XFS/XFG patients compared with controls. In a subset of XFS/XFG patients, chart reviews were conducted to confirm clinically diagnosed AAA.

RESULTS

In the AAA pilot, 20 patients (0.3%) and 118 controls (0.3%) developed XFS/XFG, respectively. We observed no increased risk of XFS/XFG in AAA patients compared with non-AAA-matched controls (HR = 0.99, 95% CI 0.6-1.6). Among XFS/XFG study patients and controls, 122 patients (3.6%) and 376 controls (3.7%) had an AAA diagnosis. We likewise observed no increased risk of AAA in XFS/XFG patients (OR = 0.97, 95% CI 0.8-1.2). In 14 XFS/XFG patients with an ICD 9/10 diagnosis of AAA who underwent chart review, a clinical diagnosis of AAA was confirmed in 9 patients (64.3%).

CONCLUSION

Our findings do not support an association between AAA and XFS/XFG.

HDL metabolism and functions impacting on cell cholesterol homeostasis are specifically altered in patients with abdominal aortic aneurysm

Background

The etiopathogenesis of abdominal aortic aneurysm (AAA) is still unclarified, but vascular inflammation and matrix metalloproteases activation have a recognized role in AAA development and progression. Circulating lipoproteins are involved in tissue inflammation and repair, particularly through the regulation of intracellular cholesterol, whose excess is associated to cell damage and proinflammatory activation. We analyzed lipoprotein metabolism and function in AAA and in control vasculopathic patients, to highlight possible non-atherosclerosis-related, specific abnormalities.

Methods

We measured fluorometrically serum esterified/total cholesterol ratio, as an index of lecithin-cholesterol acyltransferase (LCAT) activity, and cholesteryl ester transfer protein (CETP) activity in patients referred to vascular surgery either for AAA (n=30) or stenotic aortic/peripheral atherosclerosis (n=21) having similar burden of cardiovascular risk factors and disease. We measured high-density lipoprotein (HDL)-cholesterol efflux capacity (CEC), through the ATP-binding cassette G1 (ABCG1) and A1 (ABCA1) pathways and serum cell cholesterol loading capacity (CLC), by radioisotopic and fluorimetric methods, respectively.

Results

We found higher LCAT (+23%; p &lt; 0.0001) and CETP (+49%; p &lt; 0.0001) activity in AAA sera. HDL ABCG1-CEC was lower (−16%; p &lt; 0.001) and ABCA1-CEC was higher (+31.7%; p &lt; 0.0001) in AAA. Stratification suggests that smoking may partly contribute to these modifications. CEC and CETP activity correlated with CLC only in AAA.

Conclusions

We demonstrated that compared to patients with stenotic atherosclerosis, patients with AAA had altered HDL metabolism and functions involved in their anti-inflammatory and tissue repair activity, particularly through the ABCG1-related intracellular signaling. Clarifying the relevance of this mechanism for AAA evolution might help in developing new diagnostic parameters and therapeutic targets for the early management of this condition.

Right Heart Failure as an Atypical Presentation of Chronic Type A Aortic Dissection - Multimodality Imaging for Accurate Diagnosis and Treatment. A case report and mini-review of literature

Background

An intrapericardial organized haematoma secondary to chronic type A aortic dissection is an extremely rare cause of right heart failure. Imaging studies are essential in recognising and diagnosis of this distinctive medical condition and guiding the anticipated treatment.

Case presentation

A 70-year-old male patient was admitted for progressive symptoms of right heart failure. His cardiovascular history exposed an aortic valve replacement 22 years before with a Medtronic Hall 23 tilting valve with no regular follow-up. Classical signs of congestion were recognized at physical examination. Transthoracic two-dimensional echocardiography and thoraco-abdominal computed tomography angiography, as essential parts of multimodality imaging algorithm, established the underlying cause of right heart failure. Under total cardiopulmonary bypass and cardiac arrest, surgical removal of the haematoma and proximal repair of the ascending aorta with a patient-matched vascular graft were successfully performed. The patient was discharged in good condition with appropriate pharmacological treatment, guideline-directed; no imagistic signs of acute post-surgery complications were ascertained.

Conclusion

This paper highlights the importance of recognizing and providing a timely clinical and imagistic diagnosis of this very rare, potentially avoidable cause of right heart failure in patients with previous cardiac surgery.

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.

Abdominal Aortic Aneurysm Formation with a Focus on Vascular Smooth Muscle Cells

Abdominal aortic aneurysm (AAA) is a lethal degenerative vascular disease that affects, mostly, the elder population, with a high mortality rate (>80%) upon rupture. It features a dilation of the aortic diameter to larger than 30 mm or more than 50%. Diverse pathological processes are involved in the development of AAA, including aortic wall inflammation, elastin breakdown, oxidative stress, smooth muscle cell (SMC) phenotypic switching and dysfunction, and extracellular matrix degradation. With open surgery being the only therapeutic option up to date, the lack of pharmaceutical treatment approach calls for identifying novel and effective targets and further understanding the pathological process of AAA. Both lifestyle and genetic predisposition have an important role in increasing the risk of AAA. Several cell types are closely related to the pathogenesis of AAA. Among them, vascular SMCs (VSMCs) are gaining much attention as a critical contributor for AAA initiation and/or progression. In this review, we summarize what is known about AAA, including the risk factors, the pathophysiology, and the established animal models of AAA. In particular, we focus on the VSMC phenotypic switching and dysfunction in AAA formation. Further understanding the regulation of VSMC phenotypic changes may provide novel therapeutic targets for the treatment or prevention of AAA.

AAA Revisited: A Comprehensive Review of Risk Factors, Management, and Hallmarks of Pathogenesis

Despite declining incidence and mortality rates in many countries, the abdominal aortic aneurysm (AAA) continues to represent a life-threatening cardiovascular condition with an overall prevalence of about 2-3% in the industrialized world. While the risk of AAA development is considerably higher for men of advanced age with a history of smoking, screening programs serve to detect the often asymptomatic condition and prevent aortic rupture with an associated death rate of up to 80%. This review summarizes the current knowledge on identified risk factors, the multifactorial process of pathogenesis, as well as the latest advances in medical treatment and surgical repair to provide a perspective for AAA management.

Nicotine Exacerbates TAAD Formation Induced by Smooth Muscle-Specific Deletion of the TGF-β Receptor 2

Tobacco smoke is an established risk factor for thoracic aortic aneurysms and dissections (TAAD). However, little is known about its underlying mechanisms due to the lack of validated animal models. The present study developed a mouse model that may be utilized to investigate exacerbation of TAAD formation by mimetics of tobacco smoke. TAADs were created via inducible deletion of smooth muscle cell-specific Tgfbr2 receptors. Using this model, the first set of experiments evaluated the efficacy of nicotine salt (34.0 mg/kg/day), nicotine free base (NFB, 5.0 mg 90-day pellets), and cigarette smoke extract (0.1 ml/mouse/day). Compared with their respective control groups, only NFB pellets promoted TAAD dilation (23 ± 3% vs. 12 ± 2%, P = 0.014), and this efficacy was achieved at a cost of >50% acute mortality. Infusion of NFB with osmotic minipumps at extremely high, but nonlethal, doses (15.0 or 45.0 mg/kg/day) failed to accelerate TAAD dilation. Interestingly, costimulation with β-aminopropionitrile (BAPN) promoted TAAD dilation and aortic rupture at dosages of 3.0 and 45.0 mg/kg/day, respectively, indicating that BAPN sensitizes the response of TAADs to NFB. In subsequent analyses, the detrimental effects of NFB were associated with clustering of macrophages, neutrophils, and T-cells in areas with structural destruction, enhanced matrix metalloproteinase- (MMP-) 2 production, and pathological angiogenesis with attenuated fibrosis in the adventitia. In conclusion, modeling nicotine exacerbation of TAAD formation requires optimization of chemical form, route of delivery, and dosage of the drug as well as the pathologic complexity of TAADs. Under the optimized conditions of the present study, chronic inflammation and adventitial mal-remodeling serve as critical pathways through which NFB exacerbates TAAD formation.

Role of Ferroptosis-Related Genes in Stanford Type A Aortic Dissection and Identification of Key Genes: New Insights from Bioinformatic Analysis

Stanford type A aortic dissection (TAAD) is one of the most dangerous vascular diseases worldwide, and the mechanisms of its development remain unclear. Further molecular pathology studies may contribute to a comprehensive understanding of TAAD and provide new insights into diagnostic markers and potential therapeutic targets. Recent studies have identified that ferroptosis, a form of cell death, may play a previously unrecognized role in influencing the development of TAAD. In this study, we explored the pathological role of ferroptosis in TAAD by performing bioinformatics analyses. Gene set enrichment analysis (GSEA) showed that the ferroptosis-related gene (FRG) set was significantly different between normal and TAAD aortic samples at an overall level (p < 0.001). Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses explored the potential functions and pathways of FRG in TAAD. We further identified six key genes (CA9, HMOX1, IL6, CDKN1A, HIF1A, MYC) from differentially expressed FRGs in TAAD by constructing a protein–protein interaction (PPI) network, all key genes were upregulated in TAAD. Four of the key genes (CA9, IL6, CDKN1A, and HIF1A) were demonstrated to be correlated with cigarette smoke extract-induced ferroptosis in aortic vascular smooth muscle cells. These results suggest that ferroptosis is one of the essential pathological processes in the development of TAAD, and some FRGs affect TAAD development by mediating cellular ferroptosis, which provides deepening insights into the molecular mechanisms and potential therapeutic targets of TAAD.

Role of volume in small abdominal aortic aneurysm surveillance

OBJECTIVE

Current management of small abdominal aortic aneurysms (AAAs) primarily involves serial imaging surveillance of maximum transverse diameter (MTD) to estimate rupture risk. Other measurements, such as volume and tortuosity, are less well-studied and may help characterize and predict AAA progression. This study evaluated predictors of AAA volume growth and discusses the role of volume in clinical practice.

METHODS

Subjects from the Non-invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (baseline AAA MTD, 3.5-5.0 cm) with ≥2 computed tomography scans were included in this study (n = 250). Computed tomography scans were conducted approximately every 6 months over 2 years. MTD, volume, and tortuosity were used to model growth. Univariable and multivariable backwards elimination least squares regressions assessed associations with volume growth.

RESULTS

Baseline MTD accounted for 43% of baseline volume variance (P < .0001). Mean volume growth rate was 10.4 cm³/year (standard deviation, 8.8 cm³/year) (mean volume change +10.4%). Baseline volume accounted for 30% of volume growth variance; MTD accounted for 13% of volume growth variance. More tortuous aneurysms at baseline had significantly larger volume growth rates (difference, 32.8 cm³/year; P < .0001). Univariable analysis identified angiotensin II receptor blocker use (difference, -3.4 cm³/year; P = .02) and history of diabetes mellitus (difference, -2.8 cm³/year; P = .04) to be associated with lower rates of volume growth. Baseline volume, tortuosity index, current tobacco use, and absence of diabetes mellitus remained significantly associated with volume growth in multivariable analysis. AAAs that reached the MTD threshold for repair had a wide range of volumes: 102 cm³ to 142 cm³ in female patients (n = 5) and 105 cm³ to 229 cm³ in male patients (n = 20).

CONCLUSIONS

Baseline AAA volume and MTD were found to be moderately correlated. On average, AAA volume grows about 10% annually. Baseline volume, tortuosity, MTD, current tobacco use, angiotensin II receptor blocker use, and history of diabetes mellitus were predictive of volume growth over time.

Programmed cell death in aortic aneurysm and dissection: A potential therapeutic target

Rupture of aortic aneurysm and dissection (AAD) remains a leading cause of death. Progressive smooth muscle cell (SMC) loss is a crucial feature of AAD that contributes to aortic dysfunction and degeneration, leading to aortic aneurysm, dissection, and, ultimately, rupture. Understanding the molecular mechanisms of SMC loss and identifying pathways that promote SMC death in AAD are critical for developing an effective pharmacologic therapy to prevent aortic destruction and disease progression. Cell death is controlled by programmed cell death pathways, including apoptosis, necroptosis, pyroptosis, and ferroptosis. Although these pathways share common stimuli and triggers, each type of programmed cell death has unique features and activation pathways. A growing body of evidence supports a critical role for programmed cell death in the pathogenesis of AAD, and inhibitors of various types of programmed cell death represent a promising therapeutic strategy. This review discusses the different types of programmed cell death pathways and their features, induction, contributions to AAD development, and therapeutic potential. We also highlight the clinical significance of programmed cell death for further studies.

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.

Outcomes and predictors of mortality in a Belgian population of patients admitted with ruptured abdominal aortic aneurysm and treated by open repair in the contemporary era

BACKGROUND

Abdominal aortic aneurysm (AAA) rupture is a serious condition that results in extremely high mortality rates. Some improvements in outcome have been reported during the last 2 decades. The objective of the present study was to determine the overall and operative (by open repair) mortality related to ruptured AAA in the contemporary era and to identify preoperative, intraoperative, and early postoperative parameters associated with poor outcomes.

METHODS

We performed a retrospective review of all consecutive patients admitted to our single institution with a diagnosis of ruptured AAA between 2004 and 2013. A total of 103 parameters, including demographic characteristics, medical history, clinical and biological parameters, cardiovascular risk factors, emergency level, diagnostic modalities, time from symptoms to diagnosis and treatment, type of operative procedure and postoperative complications, were analyzed. The primary endpoint considered in this study was the cumulative incidence rate of mortality. The secondary endpoint was the identification, by logistic regression methods, of risk factors for overall mortality as well as for operative, and postoperative mortality.

RESULTS

Within our study period, 104 patients were admitted for a ruptured AAA. The majority of patients (84.6%) were male, and the AAA was known in 34.6% of the patients. Rupture occurred for a maximal diameter lower than 55 mm in 25% of the female population, compared to 5.7% of the male population (P = 0.030). The proportions of admitted patients who died before (preoperative mortality), during (intraoperative mortality) or after (postoperative hospital mortality) surgery was 17.3%, 16.3%, and 18.3%, respectively, yielding a cumulative in-hospital mortality of 51.9%. In the multivariate analysis, age ≥ 80 (P = 0.001), myocardial ischemia on the admission ECG (P = 0.046), and management by the physician response unit (P = 0.002) were the only preoperative parameters associated with a higher risk of hospital mortality. Four risk factors were found to be associated with a higher risk of postoperative mortality in the multivariate analysis, and all patients presenting with 3 or more of these risk factors (n = 5) died.

CONCLUSIONS

The overall mortality of ruptured AAA in a contemporary cohort of patients who underwent open repair remains high and does not seem to have decreased during recent decades. Ruptures occur at smaller diameters in women than in men, supporting a lower threshold for intervention in women with known AAA. We developed risk scores to predict the mortality of patients with rAAA at different times of their hospital course. The validity of these scores should be assessed in prospective clinical studies.

Nicotine promotes vascular calcification via intracellular Ca2+-mediated, Nox5-induced oxidative stress and extracellular vesicle release in vascular smooth muscle cells

Aims

Smokers are at increased risk of cardiovascular events. However, the exact mechanisms through which smoking influences cardiovascular disease resulting in accelerated atherosclerosis and vascular calcification are unknown. The aim of this study was to investigate effects of nicotine on initiation of vascular smooth muscle cell (VSMC) calcification and to elucidate underlying mechanisms.

Methods and results

We assessed vascular calcification of 62 carotid lesions of both smoking and non-smoking patients using ex vivo micro-computed tomography (µCT) scanning. Calcification was present more often in carotid plaques of smokers (n = 22 of 30, 73.3%) compared to non-smokers (n = 11 of 32, 34.3%; P < 0.001), confirming higher atherosclerotic burden. The difference was particularly profound for microcalcifications, which was 17-fold higher in smokers compared to non-smokers. In vitro, nicotine-induced human primary VSMC calcification, and increased osteogenic gene expression (Runx2, Osx, BSP, and OPN) and extracellular vesicle (EV) secretion. The pro-calcifying effects of nicotine were mediated by Ca²⁺-dependent Nox5. SiRNA knock-down of Nox5 inhibited nicotine-induced EV release and calcification. Moreover, pre-treatment of hVSMCs with vitamin K2 ameliorated nicotine-induced intracellular oxidative stress, EV secretion, and calcification. Using nicotinic acetylcholine receptor (nAChR) blockers α-bungarotoxin and hexamethonium bromide, we found that the effects of nicotine on intracellular Ca²⁺ and oxidative stress were mediated by α7 and α3 nAChR. Finally, we showed that Nox5 expression was higher in carotid arteries of smokers and correlated with calcification levels in these vessels.

Conclusion

In this study, we provide evidence that nicotine induces Nox5-mediated pro-calcific processes as novel mechanism of increased atherosclerotic calcification. We identified that activation of α7 and α3 nAChR by nicotine increases intracellular Ca²⁺ and initiates calcification of hVSMCs through increased Nox5 activity, leading to oxidative stress-mediated EV release. Identifying the role of Nox5-induced oxidative stress opens novel avenues for diagnosis and treatment of smoking-induced cardiovascular disease.

Ferritinophagy and ferroptosis in cardiovascular disease: Mechanisms and potential applications

Ferroptosis is a type of regulated cell death driven by iron dependent accumulation of cellular reactive oxygen species (ROS) when glutathione (GSH)-dependent lipid peroxidation repair systems are compromised. Nuclear receptor co-activator 4 (NCOA4)-mediated selective autophagy of ferritin, termed ferritinophagy, involves the regulation of ferroptosis. Emerging evidence has revealed that ferritinophagy and ferroptosis exert a significant role in the occurrence and development of cardiovascular disease. In the present review, we aimed to present a brief overview of ferritinophagy and ferroptosis focusing on the underlying mechanism and regulations involved. We summarize and discuss relevant research progress on the role of ferritinophagy and ferroptosis in cardiovascular diseases accompanied with potential applications of ferritinophagy and ferroptosis modulators in the treatment of ferroptosis-associated cardiovascular diseases.

Ultrasound Imaging of the Abdominal Aorta: A Comprehensive Review

Ultrasound is the imaging modality of choice for the initial evaluation of disorders that involve the abdominal aorta (AA). The diagnostic value of ultrasound resides in its ability to allow assessment of the anatomy and structure of the AA using two- dimensional, three-dimensional, and contrast-enhanced imaging. Moreover, ultrasound permits evaluation of the physiologic and hemodynamic consequences of abnormalities through Doppler interrogation of blood flow, thus enabling the identification and quantification of disorders within the AA and beyond its boundaries. The approach to ultrasound imaging of the AA varies, depending on the purpose of the study and whether it is performed in a radiology or vascular laboratory or in an echocardiography laboratory. The aim of this review is to demonstrate the usefulness of ultrasound imaging for the detection and evaluation of disorders that involve the AA, detail the abnormalities that are detected or further assessed, and outline its value for echocardiographers, sonographers, and radiologists.

Risk reduction and pharmacological strategies to prevent progression of aortic aneurysms

INTRODUCTION

While size thresholds exist to determine when aortic aneurysms warrant surgical intervention, there is no consensus on how best to treat this disease before aneurysms reach the threshold for intervention. Since a landmark study in 1994 first suggested ß-blockers may be useful in preventing aortic aneurysm growth, there has been a surge in research investigating different pharmacologic therapies for aortic aneurysms - with very mixed results.

AREAS COVERED

We have reviewed the existing literature on medical therapies used for thoracic and abdominal aortic aneurysms in humans. These include ß-blockers, angiotensin II receptor blockers, and angiotensin-converting enzyme inhibitors as well as miscellaneous drugs such as tetracyclines, macrolides, statins, and anti-platelet medications.

EXPERT OPINION

While multiple classes of drugs have been explored for risk reduction in aneurysm disease, with few exceptions results have been disappointing with an abundance of contradictory findings. The vast majority of studies have been done in patients with abdominal aortic aneurysms or thoracic aortic aneurysm patients with Marfan Syndrome. There exists a striking gap in the literature when it comes to pharmacologic management of non-Marfan Syndrome patients with thoracic aortic aneurysms. Given the differences in pathogenesis, this is an important future direction for aortic aneurysm research.

Global Burden of Aortic Aneurysm and Attributable Risk Factors from 1990 to 2017

Background

To date, our understanding of the global aortic aneurysm (AA) burden distribution is very limited.

Objective

To assess a full view of global AA burden distribution and attributable risk factors from 1990 to 2017.

Methods

We extracted data of AA deaths, disability-adjusted life years (DALYs), and their corresponding age-standardized rates (ASRs), in general and by age/sex from the 2017 Global Burden of Disease (GBD) study. The current AA burden distribution in 2017 and its changing trend from 1990 to 2017 were separately showed. The spatial divergence was discussed from four levels: global, five social-demographic index regions, 21 GBD regions, and 195 countries and territories. We also estimated the risk factors attributable to AA related deaths.

Results

Globally, the AA deaths were 167,249 with an age-standardized death rate (ASDR) of 2.19/100,000 persons in 2017, among which the elderly and the males accounted for the majority. Although reductions in ASRs were observed in developed areas, AA remained an important health issue in those relatively underdeveloped areas and might be much more important in the near future. AA may increasingly affect the elderly and the female population. Similar patterns of AA DALYs burden were noted during the study period. AA burden attributable to high blood pressure and smoking decreased globally and there were many heterogeneities in their distribution.

Discussion

AA maintained an incremental public health issue worldwide. The change pattern of AA burden was heterogeneous across locations, ages, and sexes and it is paramount to improve resource allocation for more effective and targeted prevention strategies. Also, prevention of tobacco consumption and blood pressure control should be emphasized.

Editor's Choice - Decrease in Mortality from Abdominal Aortic Aneurysms (2001 to 2015): Is it Decreasing Even Faster?

OBJECTIVE

The early twenty first century witnessed a decrease in mortality from abdominal aortic aneurysms (AAA), which was associated with variations in the prevalence of cardiovascular risk factors. This study investigated whether these trends continued into the second decade of the twenty first century.

METHODS

Information on AAA mortality (2001 - 2015) using International Classification of Diseases codes was extracted from the World Health Organization (WHO) mortality database. Data on risk factors were extracted from the Institute of Health Metrics and Evaluation and WHO InfoBase, and data on population from the World Development Indicators database. Regression analysis of temporal trends in cardiovascular risk factors was done independently for correlations with AAA mortality trends.

RESULTS

Seventeen countries across four continents met the inclusion criteria (Australasia, two; Europe, 11; North America, two; Asia, two). Male AAA mortality decreased in 13 countries (population weighted average: -2.84%), while female AAA mortality decreased in 11 countries (population weighted average: -1.64%). The decrease in AAA mortality was seen in both younger (< 65 years) and older (> 65 years) patients. The decrease in AAA mortality was more marked in the second decade of the twenty first century (2011 - 2015) compared with the first decade (2001 - 2005 and 2006 - 2010). Trends in AAA mortality positively correlated with smoking (males: p = .03X, females: p = .001) and hypertension (males: p = .001, females: p = .01X). Conversely, AAA mortality negatively correlated with obesity (males: p = .001, females: p = .001), while there was no significant correlation with diabetes.

CONCLUSION

AAA mortality has continued to decline and seems to have declined at an even faster rate in the second decade of the twenty first century, albeit with heterogeneity among countries. These variations are multifactorial in origin but further efforts targeting smoking cessation and blood pressure control will probably contribute to continued reductions in AAA mortality.

Ferroptosis and its emerging roles in cardiovascular diseases

Ferroptosis is a new form of regulated cell death (RCD) driven by iron-dependent lipid peroxidation, which is morphologically and mechanistically distinct from other forms of RCD including apoptosis, autophagic cell death, pyroptosis and necroptosis. Recently, ferroptosis has been found to participate in the development of various cardiovascular diseases (CVDs) including doxorubicin-induced cardiotoxicity, ischemia/reperfusion-induced cardiomyopathy, heart failure, aortic dissection and stroke. Cardiovascular homeostasis is indulged in delicate equilibrium of assorted cell types composing the heart or vessels, and how ferroptosis contributes to the pathophysiological responses in CVD progression is unclear. Herein, we reviewed recent discoveries on the basis of ferroptosis and its involvement in CVD pathogenesis, together with related therapeutic potentials, aiming to provide insights on fundamental mechanisms of ferroptosis and implications in CVDs and associated disorders.

Associations of global DNA methylation and homocysteine levels with abdominal aortic aneurysm: A cohort study from a population-based screening program in Sweden

Abdominal aortic aneurysm (AAA) is a life-threatening condition with a mortality rate of over 80%. Persistent smoking, which is a risk factor for AAA, has lasting effects on DNA methylation. Moreover, a plasma-amino acid, homocysteine, previously implicated in vascular diseases, including aneurysms, has well-established biological association with methylation. In the present study, we aimed to determine the global DNA methylation, homocysteine levels and their association with AAA and its growth. Enzyme-linked immunosorbent assay (ELISA) was used to quantify global DNA methylation in whole blood-DNA samples and diagnostic enzymatic assay quantified plasma homocysteine, from 65-year old men with (n = 116) and without AAA (n = 230) diagnosed at ultrasound screening. We found significantly higher global DNA methylation (p < .001) and homocysteine levels (p < .001) in men with AAA compared to those without AAA, and direct linear associations with baseline aortic diameter. On multivariable regression analysis, global DNA methylation (odds ratio [OR]: 1.8; 95% confidence interval [CI]: 1.1-2.9) and homocysteine levels (OR: 1.1; 95% CI:1.0-1.1) were positively associated with AAA, independent of smoking, medication use, and major co-morbidities. However, we did not find any significant association between DNA methylation or homocysteine levels with AAA growth during follow-up. We found that global DNA methylation and homocysteine levels are higher in men with AAA but are not associated with AAA growth. This indicates that different pathways and mechanisms may be involved in initiation and progression of AAA. More studies are needed to understand the precise role of DNA methylation, homocysteine and their interplay in AAA pathophysiology.

Risk Factors and Mouse Models of Abdominal Aortic Aneurysm Rupture

Abdominal aortic aneurysm (AAA) rupture is an important cause of death in older adults. In clinical practice, the most established predictor of AAA rupture is maximum AAA diameter. Aortic diameter is commonly used to assess AAA severity in mouse models studies. AAA rupture occurs when the stress (force per unit area) on the aneurysm wall exceeds wall strength. Previous research suggests that aortic wall structure and strength, biomechanical forces on the aorta and cellular and proteolytic composition of the AAA wall influence the risk of AAA rupture. Mouse models offer an opportunity to study the association of these factors with AAA rupture in a way not currently possible in patients. Such studies could provide data to support the use of novel surrogate markers of AAA rupture in patients. In this review, the currently available mouse models of AAA and their relevance to the study of AAA rupture are discussed. The review highlights the limitations of mouse models and suggests novel approaches that could be incorporated in future experimental AAA studies to generate clinically relevant results.

Pathophysiology of Aortic Aneurysms: Insights from Animal Studies

Aortic aneurysms are defined as dilations of the aorta greater than 50 percent. Currently, the only effective treatment for aortic aneurysms is surgical repair, which is recommended only to those that meet criteria. There is no available pharmaceutical therapy to slow aneurysm growth and thus prevent lethal rupture. The development of a number of murine models has allowed in depth studies of various cellular and extracellular components of aneurysm pathophysiology. The identification of key therapeutic targets has resulted in several clinical trials evaluating pharmaceutical candidates to treat aneurysm progression. In this review, we focus on providing recent updates on developments in murine models of aortic aneurysm. In addition, we discuss recent studies of the various cellular and extracellular components of the aorta along with the abutting aortic structures that contribute to aneurysm development and progression.

Extended screening guidelines for the diagnosis of abdominal aortic aneurysm

BACKGROUND

The U.S. Preventive Services Task Force (USPSTF) guidelines are the most widely used criteria for screening for abdominal aortic aneurysms (AAA). However, when the USPSTF criteria are applied retrospectively to a group of patients who have undergone treatment for AAA, there are many patients who satisfy none of the AAA screening criteria. The more sensitive Society for Vascular Surgery (SVS) guidelines have expanded the criteria for screening for AAA with the hope of capturing a greater fraction of those individuals who can undergo treatment for their AAA before presenting with AAA rupture. We sought to identify the number of patients who would have been identified as having criteria for screening for AAA by both the USPSTF and SVS criteria, in a cohort of patients who have undergone treatment for AAA.

METHODS

We assessed demographic, comorbidity, and perioperative complication data for all patients undergoing endovascular and open AAA repair in the Vascular Quality Initiative. Patients meeting each of the screening criteria were identified. Clinical factors and demographic variables were collected.

RESULTS

We identified 55,197 patients undergoing AAA repair in the Vascular Quality Initiative, including 44,602 patients who underwent endovascular aneurysm repair (EVAR) and 10,595 patients undergoing open repair. Of these, the USPTF guidelines would have identified fewer than one-third of patients (32% EVAR and 33% open repair). Applying the SVS guidelines increased the number meeting criteria for screening by 6% and 12% for the EVAR and open repair cohorts, respectively. Finally, adoption of the expanded SVS guidelines (including the "weak recommendations") would have identified an additional 34% of EVAR patients and 21% of open AAA repair patients. Use of the expanded criteria would have resulted in 27% of patients undergoing EVAR and 33% of patients undergoing open AAA repair who would not have met any screening criteria. In EVAR patients not meeting the criteria, 52% were younger than 65 years had a history of heavy smoking. Of all those who did not meet screening criteria, ruptured AAA was twice as prevalent as those who met screening criteria (8.5% vs 4.4%; P ≤ .0001).

CONCLUSIONS

Expanding established USPSTF screening guidelines to include the expanded SVS criteria may potentially double the number of patients identified with AAA. Smokers under the age of 65, and elderly patients 70 and older with no smoking history, represent two groups with AAA and potentially twice the risk of presenting with rupture.

Cigarette smoke extract induces ferroptosis in vascular smooth muscle cells

Cigarette smoking is a major risk factor for aortic aneurysm and dissection; however, no causative link between smoking and these aortic disorders has been proven. In the present study, we investigated the mechanism by which cigarette smoke affects vascular wall cells and found that cigarette smoke extract (CSE) induced a novel form of regulated cell death termed ferroptosis in vascular smooth muscle cells (VSMCs). CSE markedly induced cell death in A7r5 cells and primary rat VSMCs, but not in endothelial cells, which was completely inhibited by specific ferroptosis inhibitors [ferrostatin-1 (Fer-1) and Liproxstatin-1] and an iron chelator (deferoxamine). CSE-induced VSMC death was partially inhibited by a GSH precursor (N-acetyl cysteine) and an NADPH oxidase inhibitor [diphenyleneiodonium chloride (DPI)], but not by inhibitors of pan-caspases (Z-VAD), caspase-1 (Z-YVAD), or necroptosis (necrostatin-1). CSE also upregulated IL-1β, IL-6, TNF-α, matrix metalloproteinase (MMP)-2, MMP-9, and TIMP-1 (tissue inhibitor of metalloproteinase)in A7r5 cells, which was inhibited by Fer-1. Furthermore, CSE induced the upregulation of Ptgs2 mRNA, lipid peroxidation, and intracellular GSH depletion, which are key features of ferroptosis. VSMC ferroptosis was induced by acrolein and methyl vinyl ketone, major constituents of CSE. Furthermore, CSE caused medial VSMC loss in ex vivo aortas. Electron microscopy analysis showed mitochondrial damage and fragmentation in medial VSMCs of CSE-treated aortas. All of these manifestations were partially restored by Fer-1. These findings demonstrate that ferroptosis is responsible for CSE-induced VSMC death and suggest that ferroptosis is a potential therapeutic target for preventing aortic aneurysm and dissection.NEW & NOTEWORTHY Cigarette smoke extract (CSE)-induced cell death in rat vascular smooth muscle cells (VSMCs) was completely inhibited by specific ferroptosis inhibitors and an iron chelator. CSE also induced the upregulation of Ptgs2 mRNA, lipid peroxidation, and intracellular GSH depletion, which are key features of ferroptosis. CSE caused medial VSMC loss in ex vivo aortas. These findings demonstrate that ferroptosis is responsible for CSE-induced VSMC death.

Prevalence and Epidemiological Pattern of Abdominal Aortic Aneurysms in Africa: A Systematic Review

Introduction

The incidence of abdominal aortic aneurysms (AAAs) in high-income countries has been declining in the last three decades. However, in most low-income and middle-income countries especially in Africa, little is known about its burden. The absence of screening services for AAA in African countries makes it difficult to detect and promptly manage AAA before rupture, which has significant implications for mortality. This study sought to systematically assess the prevalence of AAA amongst patients visiting hospitals in Africa and evaluate its epidemiological pattern.

Materials and Methods

A systematic review was performed on the EMBASE, GLOBAL HEALTH, MEDLINE, and PUBMED databases. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement standards and protocol registered with PROSPERO (CRD42020162214). A data extraction tool was used to get relevant information from these studies. Quality assessment and risk of bias were performed using the Newcastle Ottawa Scale for cross-sectional studies. Results were summarised in tables, figures, and a forest plot. A narrative synthesis approach of the articles was taken.

Results

Two hundred and sixty-one studies were identified and after the exclusion of 246, a final 15 were deemed suitable for analysis. A total of 4012 participants were screened for AAA and of these, 129 cases were identified. The prevalence of AAA in these studies ranged from 0.7 to 6.4%. Male participants accounted for 115 (89.1%) of the cases. There was a wide age range (31-72 years) reflective of both its possible infective and degenerative aetiology. AAA was reported to be associated with hypertension, smoking, advanced age, coronary artery disease, and HIV infection. There was no association between AAA and diabetes. Over 50% of cases were identified incidentally. About one-third (23-54%) of the participants presented aortic rupture with a mortality rate ranging between 65 and 72%.

Conclusions

AAA prevalence in Africa is probably higher than the current thinking as there is no baseline data to compare with. Aetiologically, AAA was shown to be associated with hypertension, smoking, coronary artery disease, and possibly infectious pathologies like HIV. Large epidemiological studies would help better characterise AAA in this setting. Lastly, efforts targeting the reduction of the risk factors for AAA would go a long way in reducing the burden of AAA.

Comorbidities Associated with Large Abdominal Aortic Aneurysms

Background  Abdominal aortic aneurysm has become increasingly important owing to demographic changes. Some other diseases, for example, cholecystolithiasis, chronic obstructive pulmonary disease, and hernias, seem to co-occur with abdominal aortic aneurysm. The aim of this retrospective analysis was to identify new comorbidities associated with abdominal aortic aneurysm.

Methods  We compared 100 patients with abdominal aortic aneurysms and 100 control patients. Their preoperative computed tomographic scans were examined by two investigators independently, for the presence of hernias, diverticulosis, and cholecystolithiasis. Medical records were also reviewed. Statistical analysis was performed using univariate analysis and multiple logistic regression analysis.

Results  The aneurysm group had a higher frequency of diverticulosis ( p  = 0.008). There was no significant difference in the occurrence of hernia ( p  = 0.073) or cholecystolithiasis ( p  = 1.00). Aneurysm patients had a significantly higher American Society of Anesthesiology score (2.84 vs. 2.63; p  = 0.015) and were more likely to have coronary artery disease ( p  < 0.001), congestive heart failure ( p  < 0.001), or chronic obstructive pulmonary disease ( p  < 0.001). Aneurysm patients were more likely to be former ( p  = 0.034) or current ( p  = 0.006) smokers and had a significantly higher number of pack years ( p  < 0.001). Aneurysm patients also had a significantly poorer lung function. In multivariate analysis, the following factors were associated with aneurysms: chronic obstructive pulmonary disease (odds ratio, OR = 12.24; p  = 0.002), current smoking (OR = 4.14; p  = 0.002), and coronary artery disease (OR = 2.60; p  = 0.020).

Conclusions  Our comprehensive analysis identified several comorbidities associated with abdominal aortic aneurysms. These results could help to recognize aneurysms earlier by targeting individuals with these comorbidities for screening.

Genome-Wide Expression Profiling Unveils Autoimmune Response Signatures in the Perivascular Adipose Tissue of Abdominal Aortic Aneurysm

Objective- Perivascular adipose tissue (PVAT) is thought to play a role in vascular homeostasis and in the pathogenesis of large vessel diseases, including abdominal aortic aneurysm (AAA). Herein, we tested the hypothesis that locally restricted transcriptional profiles characterize PVAT surrounding AAA, indicating specific dysfunctions associated with the disease. Approach and Results- Using a paired sample design to limit the effects of interindividual variation, we performed a microarray-based investigation of the PVAT transcriptome in 30 patients with AAA, comparing the adipose layer of the dilated abdominal aorta with that of the not-dilated aortic neck in each patient. Furthermore, we used a state-of-the-art data mining procedure to remove the effect of confounders produced by high-throughput gene expression techniques. We found substantial differences in PVAT gene expression clearly distinguishing the dilated from the not-dilated aorta, which increased in number and magnitude with increasing AAA diameter. Comparisons with other adipose depots (omental or subcutaneous fat) confirmed that gene expression changes are locally restricted. We dissected putative mechanisms associated with AAA PVAT dysfunction through a functional enrichment network analysis: both innate and adaptive immune-response genes along with genes related to cell-death pathways, metabolic processes of collagen, sphingolipids, aminoglycans, and extracellular matrix degradation were strongly overrepresented in PVAT of AAA compared with PVAT of the not-dilated aorta. Conclusions- Our results support a possible function of PVAT in AAA pathogenesis and suggest that AAA is an immunologic disease with an underlying autoimmune component. Interfering with these disease-specific pathways would clarify their precise role in AAA pathogenesis.

Cigarette Smoke Extract Activates Tartrate-Resistant Acid Phosphatase-Positive Macrophage

BACKGROUND

It has been reported that smoking is one of the strongest positive risk factors for abdominal aortic aneurysms (AAAs). Although many studies have been directed to decipher the effect of smoking on AAA, its effect on macrophage activation has not yet been explored.

OBJECTIVES

We have reported the importance of osteoclastogenesis (OCG) in aneurysm formation. Therefore, we examined the effect of cigarette smoking on OCG and arterial aneurysmal formation by using cigarette smoke extract (CSE) in this study.

METHODS

Macrophage cell lines were stimulated with CSE, and their activation and differentiation were examined in vitro. Since macrophages activated through the OCG pathway are identified by tartrate-resistant acid phosphatase (TRAP) expression, these cells are referred to as TRAP-positive macrophages (TPMs) in this study. We also applied CSE-contained PBS in the calcium chloride-induced mouse carotid aneurysm model in vivo.

RESULTS

Macrophages stimulated with CSE expressed significantly higher levels of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), TRAP, cathepsin K, matrix metalloproteinase-9 and membrane-type metalloproteinase (MT1-MMP). CSE-treated mouse aneurysms showed increased aneurysm size with increased TPM infiltration and protease expression compared to non-CSE-treated mouse aneurysms.

CONCLUSIONS

These results suggest that CSE intensifies OCG in macrophages and promotes arterial aneurysmal progression.

Bioengineering an Artificial Human Blood⁻Brain Barrier in Rodents

Our group has recently created a novel in-vivo human brain organoid vascularized with human iPSC-derived endothelial cells. In this review article, we discuss the challenges of creating a perfused human brain organoid model in an immunosuppressed rodent host and discuss potential applications for neurosurgical disease modeling.

Screening based on risk factors for abdominal aortic aneurysm in the cardiology clinic

BACKGROUND

The risk factors for abdominal aortic aneurysm (AAA) are present in many of the patients that attend our cardiology service. The aim of this study was the evaluation of the prospects of examining the abdominal aorta during our consultations and the relationship of AAA with risk factors and ischemic cardiopathy.

METHODS

A descriptive transversal observational study was designed including 274 male patients aged ≥60 years, attended consecutively in the cardiology service, in which we studied the abdominal aorta and adjusted a logistic regression model to determine the risk factors associated with AAA.

RESULTS

We were able to visualize and measure the abdominal aorta in 95.4% of cases in a fast and reliable way. The prevalence of AAA was 8.76%. 75% of patients with AAA presented ischemic heart disease. Patients with AAA were characterized by the presence of ischemic cardiopathy (Odds Ratio (OR): 4.27, 95% Confidence Interval (CI): 1.37-13.31, p = 0.012), dyslipidemia (OR: 4.99, 95% CI: 1, 07-23.31; p = 0.041), arterial hypertension (OR: 4.14, 95% CI: 1.07-15.98, p = 0.039), and a longer history of smoking (OR: 1.03; 95% CI: 1002-1.054; p = 0.037).

CONCLUSIONS

The evaluation of the abdominal aorta during cardiology consultations is feasible with the standard resources. Patients treated in the cardiology service present a high prevalence of AAA. We have adjusted and validated a clinical prediction model based on risk factors that allows the identification, in the cardiology consult, of patients with the highest risk of suffering from AAA.

After 50 Years of Heart Transplants: What Does the Next 50 Years Hold for Cardiovascular Medicine? A Perspective From the International Society for Applied Cardiovascular Biology

The first successful heart transplant 50 years ago by Dr.Christiaan Barnard in Cape Town, South Africa revolutionized cardiovascular medicine and research. Following this procedure, numerous other advances have reduced many contributors to cardiovascular morbidity and mortality; yet, cardiovascular disease remains the leading cause of death globally. Various unmet needs in cardiovascular medicine affect developing and underserved communities, where access to state-of-the-art advances remain out of reach. Addressing the remaining challenges in cardiovascular medicine in both developed and developing nations will require collaborative efforts from basic science researchers, engineers, industry, and clinicians. In this perspective, we discuss the advancements made in cardiovascular medicine since Dr. Barnard's groundbreaking procedure and ongoing research efforts to address these medical issues. Particular focus is given to the mission of the International Society for Applied Cardiovascular Biology (ISACB), which was founded in Cape Town during the 20th celebration of the first heart transplant in order to promote collaborative and translational research in the field of cardiovascular medicine.

Cigarette Smoking and Subclinical Peripheral Arterial Disease in Blacks of the Jackson Heart Study

Background Prevalence of peripheral artery disease ( PAD ) is significantly higher among blacks as compared with non-Hispanic whites, but the role of cigarette smoking in PAD is understudied in blacks. We aimed to evaluate the relationship between cigarette smoking and PAD in blacks in the (JHS) Jackson Heart Study. Methods and Results JHS participants (n=5306) were classified by self-reported baseline smoking status into current, past (smoked at least 400 cigarettes/life), or never smokers. We examined multivariable logistic and robust linear regression models to estimate the associations between baseline smoking status, smoking intensity, and measures of subclinical PAD (ankle-brachial index [visit 1] and aortic calcium by computed tomography [visit 2]) to yield odds ratios and β-coefficients (estimated adjusted difference) to compare each smoking status with never smokers (reference group). There were 3579 (68%) never smokers, 986 (19%) past smokers, and 693 (13%) current smokers self-identified at baseline. After adjustment for covariates, current smokers had increased risk of ankle-brachial index <1 (odds ratio, 2.2, 95% CI, 1.5-3.3) and increased risk of abdominal aortic (odds ratio, 8.4, 95% CI, 5.8-12.0) and aortoiliac calcium (odds ratio, 9.6, 95% CI, 6.7-13.7). When stratifying by smoking intensity, those smoking more than 20 cigarettes daily (1 pack) had higher likelihood of subclinical PAD by all of these measures compared with lower-intensity use, suggesting a dose-dependent relationship. Conclusions In a large black cohort, cigarette smoking was associated with measures of subclinical PAD in a dose-dependent manner. These findings highlight the association between smoking and PAD in blacks and support further research exploring the impact of interventions on smoking cessation to reduce PAD in this population.

Educational Case: Symptomatic but Unruptured Abdominal Aortic Aneurysm

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.

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.

Targeting cysteinyl-leukotrienes in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is an asymptomatic dilatation of the vessel wall exceeding the normal vessel diameter by 50%, accompanied by intramural thrombus formation. Since the aneurysm can rupture, AAA is a life-threatening vascular disease, which may be amenable to surgical repair. At present, no pharmacological therapy for AAA is available. The 5-lipoxygenase (5-LOX) pathway of arachidonic acid metabolism leads to biosynthesis of leukotrienes (LTs), potent lipid mediators with pro-inflammatory biological actions. Among the LTs, cysteinyl-leukotrienes (cys-LT) are well-recognized signaling molecules in human asthma and allergic rhinitis. However, the effects of these molecules in cardiovascular diseases have only recently been explored. Drugs antagonizing the CysLT1 receptor, termed lukasts and typified by montelukast, are established therapeutics for clinical management of asthma. Lukasts are safe, well-tolerated drugs that can be administered during long time periods. Here we describe recent data indicating that montelukast may be used for prevention and treatment of AAA, thus representing a promising pharmacological tool for a deadly vascular disease with significant socio-economic impact.