Influence of sex on expansion rate of abdominal aortic aneurysms

Medical treatments for abdominal aortic aneurysm: an overview of clinical trials

INTRODUCTION

Abdominal aortic aneurysm is a progressive, segmental, abdominal aortic dilation associated with a high mortality rate. Abdominal aortic aneurysms with diameters larger than 55 mm are associated with a high risk of rupture, and the most effective treatment options are surgical repair. Close observation and lifestyle adjustments are recommended for smaller abdominal aortic aneurysms with lower rupture risk. The development of medical therapies that limit or prevent the progression, expansion, and eventual rupture of abdominal aortic aneurysms remains an unmet clinical need.

AREAS COVERED

This review provides an overview of completed and ongoing clinical trials examining the efficacies of various drug classes, including antibiotics, antihypertensive drugs, hypolipidemic drugs, hypoglycemic drugs, and other potential therapies for abdominal aortic aneurysms. A search of PubMed, Web of Science, Clinical Trials, and another six clinical trial registries was conducted in January 2024.

EXPERT OPINION

None of the drugs have enough evidence to indicate that they can effectively inhibit the dilation of abdominal aortic aneurysm. More clinical trial data is required to support the efficacy of propranolol. Future research should also explore different drug delivery mechanisms, such as nanoparticles, to elevate drug concentration at the aneurysm wall.

Evaluating growth patterns of abdominal aortic aneurysms among women

OBJECTIVE

Though initially protected from vessel dilation by estrogen, women may experience rapid abdominal aortic aneurysm (AAA) growth post-menopause. The rate of growth has been poorly defined in prior literature. Here, we describe aneurysm growth in a cohort of women found through an AAA screening program.

METHODS

Women with AAAs were retrospectively identified. Aortic imaging was reviewed, and measurements of maximum transverse and anterior-posterior diameters were completed. Growth was stratified by the type of aortic pathology (fusiform aneurysm, aortic ectasia, dissection with aneurysmal degeneration, saccular aneurysm) as well as size category (<3 cm, 3.0-3.9 cm, 4.0-4.9 cm, ≥5.0 cm) at diagnosis.

RESULTS

A cohort of 488 women was identified; 286 had multiple scans for review. The mean age of the entire cohort was 75 ± 9.9 years. Stratified by type of pathology, the mean age was 76 ± 8.9 years in patients with a fusiform AAA, 74 ± 9.8 years in ectasia, 65 ± 13.7 years in dissection, and 76 ± 5.6 years in saccular aneurysms. The maximum growth was highest in women with fusiform AAAs, followed by dissection, ectasia, and saccular pathology (9.7 mm, 7.0 mm, 3.0 mm, and 2.2 mm, respectively; P < .001). Comparing mean growth by year, the highest mean growth was in fusiform AAAs (3.6 mm vs 1.75 mm in dissection; P < .001). The Shapiro-Wilk test demonstrated that mean growth per year was non-normally distributed with a right skew. Stratified by aortic diameter at the time of diagnosis, mean growth/year increased with increasing size at diagnosis in fusiform AAAs and dissection (0.91 mm for <3 cm, 2.34 mm for 3.0-3.9 cm, 2.49 mm for 4.0-4.9 mm, and 6.16 mm for ≥5.0 cm in patients with fusiform AAAs vs 0.57 mm, 0.94 mm, 1.87 mm, and 2.66 mm, respectively, for patients with dissection). Smoking history was associated with a higher mean growth/year (2.6 mm vs 3.3 mm; P < .001). Conversely, patients with a family history of AAA had a lower mean growth/year (3.2 mm vs 1.5 mm; P < .001).

CONCLUSIONS

The rate of aneurysm growth in women varies based on pathology and aneurysm size, and women experience rapid aneurysm growth at sizes greater than 4.5 cm. Current screening guidelines are inadequate, and our results demonstrate that the rate of growth of fusiform aneurysms in women is faster than in men at a smaller size and may warrant more frequent surveillance than current Society for Vascular Surgery recommendations to prevent risk of increased morbidity.

Machine learning-based prediction of abdominal aortic aneurysms for individualized patient care

OBJECTIVE

The United States Preventative Services Task Force guidelines for screening for abdominal aortic aneurysms (AAA) are broad and exclude many at risk groups. We analyzed a large AAA screening database to examine the utility of a novel machine learning (ML) model for predicting individual risk of AAA.

METHODS

We created a ML model to predict the presence of AAAs (>3 cm) from the database of a national nonprofit screening organization (AAAneurysm Outreach). Participants self-reported demographics and comorbidities. The model is a two-layered feed-forward shallow network. The ML model then generated AAA probability based on patient characteristics. We evaluated graphs to determine significant factors, and then compared those graphs with a traditional logistic regression model.

RESULTS

We analyzed a cohort of 10,033 patients with an AAA prevalence of 2.74%. Consistent with logistic regression analysis, the ML model identified the following predictors of AAA: Caucasian race, male gender, advancing age, and recent or past smoker with recent smoker having a more profound affect (P < .05). Interestingly, the ML model showed body mass index (BMI) was associated with likelihood of AAAs, especially for younger females. The ML model also identified a higher than predicted risk of AAA in several groups, including female nonsmokers with cardiac disease, female diabetics, those with a family history of AAA, and those with hypertension or hyperlipidemia at older ages. An elevated BMI conveyed a higher than expected risk in male smokers and all females. The ML model also identified a complex relationship of both diabetes mellitus and hyperlipidemia with gender. Family history of AAA was a more important risk factor in the ML model for both men and women too.

CONCLUSIONS

We successfully developed an ML model based on an AAA screening database that unveils a complex relationship between AAA prevalence and many risk factors, including BMI. The model also highlights the need to expand AAA screening efforts in women. Using ML models in the clinical setting has the potential to deliver precise, individualized screening recommendations.

Can Biomarkers and PET Imaging Predict Abdominal Aortic Aneurysm Growth Rate?

Background: Abdominal aortic aneurysm (AAA) is a life-threatening condition due to the risk of aneurysm growth and rupture. Biomarkers linked to AAA pathogenesis are attractive candidates for AAA diagnosis and prognosis. The aim of this study was to assess circulating biomarkers levels relationship with PET imaging positivity and their predictive value in AAA growth rate. Methods: A total of 164 patients with AAA had whole body [18F]FDG PET/CT examination and blood drawn for biomarkers analysis at inclusion. Of these, 121 patients had at least one follow-up imaging assessment for AAA progression. Median (quartiles) imaging follow-up period was 32.8 months (15.2-69.6 months). Results: At baseline, PET was visually positive in 28 (17%) patients. Among PET+ patients, female proportion was higher compared to PET-patients (respectively, n = 6, 21.4% vs. n = 11, 8.1%, p = 0.046). Biomarkers of inflammation (CRP, CCL18), of proteolytic activity (MMP9), of extracellular matrix, and calcification regulation (OPN, OPG) were all significantly increased in PET+ patients (p < 0.05). During follow-up, rapid AAA growth (increase in size ≥ 1 cm per year) was observed in 36 (29.8%) patients and several biomarkers (CRP, MMP9, OPN, and OPG) were increased in those patients compared to patients without rapid growth (p < 0.05). Conclusions: Although PET positivity at baseline was not associated with rapid growth, CRP levels showed a significant association.

Female-Specific Considerations in Aortic Health and Disease

The aorta plays a central role in the modulation of blood flow to supply end organs and to optimize the workload of the left ventricle. The constant interaction of the arterial wall with protective and deleterious circulating factors, and the cumulative exposure to ventriculoarterial pulsatile load, with its associated intimal-medial changes, are important players in the complex process of vascular aging. Vascular aging is also modulated by biomolecular processes such as oxidative stress, genomic instability, and cellular senescence. Concomitantly with well-established cardiometabolic and sex-specific risk factors and environmental stressors, arterial stiffness is associated with cardiovascular disease, which remains the leading cause of morbidity and mortality in women worldwide. Sexual dimorphisms in aortic health and disease are increasingly recognized and explain-at least in part-some of the observable sex differences in cardiovascular disease, which will be explored in this review. Specifically, we will discuss how biological sex affects arterial health and vascular aging and the implications this has for development of certain cardiovascular diseases uniquely or predominantly affecting women. We will then expand on sex differences in thoracic and abdominal aortic aneurysms, with special considerations for aortopathies in pregnancy.

Comprehensive framework of factors accounting for worse aortic aneurysm outcomes in females: A scoping review

Sex-based outcome studies have consistently documented worse results for females undergoing care for abdominal aortic aneurysms. This review explores the underlying factors that account for worse outcomes in the females sex. A scoping review of studies reporting sex-based disparities on abdominal aortic aneurysms was performed. The review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews. Factors that account for worse outcomes in the females sex were identified, grouped into themes, and analyzed. Key findings of each study are reported and a comprehensive framework of these factors is presented. A total of 35 studies were identified as critical in highlighting sex-based disparities in care of patients with aortic aneurysms. We identified the following 10 interrelated themes in the chain of aneurysm care that account for differential outcomes in females: natural history, risk factors, pathobiology, biomechanics, screening, morphology, device design and adherence to instructions for use, technique, trial enrollment, and social determinants. Factors accounting for worse outcomes in the care of females with aortic aneurysms were identified and described. Some factors are immediately actionable, such as screening criteria, whereas device design improvement will require further research and development. This comprehensive framework of factors affecting care of aneurysms in females should serve as a blueprint to develop education, outreach, and future research efforts to improve outcomes in females.

The Comparison of Endovascular and Open Surgical Treatment for Ruptured Abdominal Aortic Aneurysm in Terms of Safety and Efficacy on the Basis of a Single-Center 30-Year Experience

OBJECTIVE

Ruptured abdominal aortic aneurysm (rAAA) is a critical condition with a high mortality rate. Over the years, endovascular aortic repair (EVAR) has evolved as a viable treatment option in addition to open repair (OR). The primary objective of this study was to compare the safety and efficacy of EVAR and OR for the treatment of rAAA based on a comprehensive analysis of our single-centre 30-year experience.

METHODS

Patients treated for rAAA at the Department of Vascular and Endovascular Surgery, University Hospital Düsseldorf, Germany from 1 January 1993 to 31 December 2022 were included. Relevant information was retrieved from archived medical records. Patient survival and surgery-related complications were analysed.

RESULTS

None of the patient-specific markers, emergency department-associated parameters, and co-morbidities were associated with patient survival. The 30-day and in-hospital mortality was higher in the OR group vs. in the EVAR group (50% vs. 8.7% and 57.1% vs. 13%, respectively). OR was associated with more frequent occurrence of more severe complications when compared to EVAR. Overall patient survival was 56 ± 5% at 12 months post-surgery (52 ± 6% for OR vs. 73 ± 11% for EVAR, respectively) (p < 0.05). Patients ≥70 years of age showed poorer survival in the OR group, with a 12-month survival of 42 ± 7% vs. 70 ± 10% for patients <70 years of age (p < 0.05). In the EVAR group, this age-related survival advantage was not found (12-month survival: ≥70 years: 67 ± 14%, <70 years: 86 ± 13%). Gender-specific survival was similar regardless of the applied method of care.

CONCLUSION

OR was associated with more severe complications in our study. EVAR initially outperformed OR for rAAA regarding patient survival while re-interventions following EVAR negatively affect survival in the long-term. Elderly patients should be treated with EVAR. Gender does not seem to have a significant impact on survival.

Exploring the expression and potential function of follicle stimulating hormone receptor in extragonadal cells related to abdominal aortic aneurysm

INTRODUCTION

Follicle stimulating hormone (FSH) is identified to play a role in postmenopausal disease and hypothesized to affect abdominal aortic aneurysm (AAA) onset/progression in postmenopausal women. We aimed to detect FSHR gene expression in AAA tissue and cell types involved in AAA formation.

METHODS

FSH stimulation of human umbilical cord endothelial cells (HUVECs), smooth muscle cells (HUCs) and PMA-differentiated macrophages to assess gene expression of FSHR and various markers. Human macrophages activated with various stimuli were assessed for FSHR gene expression. AAA dataset, AAA tissue samples and AAA-derived smooth muscle cells (SMC) obtained from elderly female donors were assessed for FSHR gene expression. AAA-SMCs were stimulated with FSH to assess its effect on gene expression. Lastly, oxidized low-density-lipoprotein (ox-LDL) uptake and abundance of cell surface protein markers were assessed by flow cytometry after FSH stimulation of human monocytes.

RESULTS

FSH stimulation showed similar levels of gene expression in HUVECs and HUCs. Only ACTA2 was downregulated in HUCs. In PMA-differentiated macrophages, gene expression of inflammation markers was unchanged after FSH stimulation. FSHR gene expression was found to be low in the AAA datasets. Female AAA-SMCs show occasional FSHR gene expression at a very low level, yet stimulation with FSH did not affect gene expression of SMC- or inflammation markers. FSH stimulation did not impact ox-LDL uptake or alter cell surface protein expression in monocytes. While FSHR gene expression was detected in human testis tissue, it was below quantification level in all other investigated cell types, even upon activation of macrophages with various stimuli.

CONCLUSION

Despite previous reports, we did not detect FSHR gene expression in various extragonadal cell types, except in occasional female AAA-SMCs. No clear effect on cell activation was observed upon FSH stimulation in any cell type. Our data suggest that a direct effect of FSH in AAA-related extragonadal cells is unlikely to influence AAA.

A novel pre-operative risk assessment tool to identify patients at risk of contrast associated acute kidney injury after endovascular abdominal aortic aneurysm repair

OBJECTIVES

Contrast-associated acute kidney injury (CA-AKI) after endovascular abdominal aortic aneurysm repair (EVAR) is associated with mortality and morbidity. Risk stratification remains a vital component of preoperative evaluation. We sought to generate and validate a pre-procedure CA-AKI risk stratification tool for elective EVAR patients.

METHODS

We queried the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) database for elective EVAR patients and excluded those on dialysis, with a history of renal transplant, death during procedure, and without creatinine measures. Association with CA-AKI (rise in creatinine > 0.5 mg/dL) was tested using mixed effects logistic regression. Variables associated with CA-AKI were used to generate a predictive model via a single classification tree. The variables selected by the classification tree were then validated by fitting a mixed effects logistic regression model into the Vascular Quality Initiative (VQI) dataset.

RESULTS

Our derivation cohort included 7,043 patients, 3.5% of whom developed CA-AKI. After multivariate analysis, age (OR 1.021, 95% CI 1.004-1.040), female sex (OR 1.393, CI 1.012-1.916), GFR < 30 ml/min (OR 5.068, CI 3.255-7.891), current smoking (OR 1.942, CI 1.067-3.535), COPD (OR 1.402, CI 1.066-1.843), maximum AAA diameter (OR 1.018, CI 1.006-1.029), and presence of iliac artery aneurysm (OR 1.352, CI 1.007-1.816) were associated with increased odds of CA-AKI. Our risk prediction calculator demonstrated that patients with a GFR <30 ml/min, females, and patients with a maximum AAA diameter of > 6.9 cm are at higher risk of CA-AKI after EVAR. Using the VQI dataset (N = 62,986), we found that GFR <30 ml/min (OR 4.668, CI 4.007-5.85), female sex (OR 1.352, CI 1.213-1.507), and maximum AAA diameter > 6.9 cm (OR 1.824, CI 1.212-1.506) were associated with increased risk of CA-AKI after EVAR.

CONCLUSIONS

Herein, we present a simple and novel risk assessment tool that can be used pre-operatively to identify patients at risk of CA-AKI after EVAR. Patients with a GFR < 30 ml/min, maximum AAA diameter > 6.9 cm, and females who are undergoing EVAR may be at risk for CA-AKI after EVAR. Prospective studies are needed to determine the efficacy of our model.

Sex difference in early mortality after abdominal aortic aneurysm repair

OBJECTIVE

Although female patients have a lower prevalence of abdominal aortic aneurysm (AAA), they seem to have a worse treatment outcome compared with male patients. Both maximum aneurysm diameter and aortic size index (ASI) are important indicators of the risk of AAA rupture, among which ASI has been shown capable of equalizing sex-related anatomical differences. Our study aimed to investigate whether sex is an independent risk factor for early postoperative mortality and how the diameter or ASI affects the association between sex and mortality.

METHODS

We performed a retrospective analysis of patients who enrolled in the AAA registry of the German Society of Vascular Surgery from 2013 to 2019. The patients were treated by either open surgical repair (OSR) or endovascular aneurysm repair (EVAR). The association between sex and 30-day mortality was investigated using logistic regression analysis. The interaction and mediating effects of maximum aneurysm diameter and ASI were investigated to verify their roles in the effect of sex on mortality. The relationships between the diameter (or ASI) and the risk of 30-day mortality in different sexes were demonstrated by the restricted cubic spline.

RESULTS

Overall, 23,275 cases were included in our analysis, with 20,130 male (86.5%) and 3139 female (13.5%) patients. Female patients had a smaller maximum aneurysm diameter (OSR, 55.23 ± 10.29 mm vs 58.05 ± 11.28 mm [P < .001]; EVAR, 54.06 ± 9.08 mm vs 56.11 ± 9.38 mm [P < .001]), but a higher ASI (OSR, 3.16 ± 0.71 vs 2.92 ± 0.69 [P < .001]; EVAR, 3.05 ± 0.66 vs 2.80 ± 0.59 [P < .001]) compared with male patients. The 30-day mortality rate was higher for female patients in both OSR (6.6% vs 4.2%; P = .002) and EVAR groups (1.8% vs 0.8%; P < .001). Logistic regression confirmed a significantly higher risk of 30-day mortality for female patients compared with male patients (odds ratio, 1.55; 95% confidence interval, 1.21-1.99; P = .001). No interaction was found between sex and diameter or ASI, but there were mediating effects for diameter and ASI in the effect of sex on 30-day mortality. For female patients, the risk of 30-day mortality linearly increased with the increase of diameter (P_Nonlinear = .089) or ASI (P_Nonlinear = .888), whereas the risk for male patients was U-shaped (for diameter, P_Nonlinear < .001; for ASI, P_Nonlinear = .020).

CONCLUSIONS

Sex is an independent risk factor for 30-day mortality after AAA repair. Both diameter and ASI are mediating factors for the effect of sex on 30-day mortality. The relationship between diameter or ASI and the risk of 30-day mortality is different for male and female patients.

Sex and Gender Bias as a Mechanistic Determinant of Cardiovascular Disease Outcomes

Defined as a prejudice either for or against something, biases at the provider, patient, and societal level all contribute to differences in cardiovascular disease recognition and treatment, resulting in outcome disparities between sexes and genders. Provider bias in the under-recognition of female-predominant cardiovascular disease and risks might result in underscreened and undertreated patients. Furthermore, therapies for female-predominant phenotypes including nonobstructive coronary artery disease and heart failure with preserved ejection fraction are less well researched, contributing to undertreated female patients. Conversely, women are less likely to seek urgent medical attention, potentially related to societal bias to put others first, which contributes to diagnostic delays. Furthermore, women are less likely to have discussions around risk factors for coronary artery disease compared with men, partially because they are less likely to consider themselves at risk for heart disease. Provider bias in interpreting a greater number of presenting symptoms, some of which have been labelled as "atypical," can lead to mislabelling presentations as noncardiovascular. Furthermore, providers might avoid discussions around certain therapies including thrombolysis for stroke, and cardiac resynchronization therapy in heart failure, because it is incorrectly assumed that women are not interested in pursuing options deemed more invasive. To mitigate bias, organizations should aim to increase the visibility and involvement of women in research, health promotion, and clinical and leadership endeavours. More research needs to be done to identify effective interventions to mitigate sex and gender bias and the resultant cardiovascular outcome discrepancies.

Female Sex Is Associated With Reintervention and Mortality Following Elective Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

While sex differences in endovascular abdominal aortic aneurysm repair (EVAR) outcomes are increasingly reported, but contributing factors remain without consensus. We investigated disparities in sex-specific outcomes following elective EVAR at our institution and evaluated factors that may predispose females to increased morbidity and mortality.

METHODS

A retrospective chart review of all patients undergoing elective EVAR from 2011 to 2020 at a suburban tertiary care center was performed. The primary outcomes were five-year survival and freedom from reintervention. Fisher's exact test, t-tests, and Kaplan-Meier analysis using the rank-log test investigated associations between sex and outcomes. A multivariable Cox proportional hazard model controlling for age and common comorbidities evaluated the effect of sex on survival and freedom from reintervention.

RESULTS

Two hundred and seventy-three patients underwent elective EVAR during the study period, including 68 (25%) females and 205 (75%) males. Females were older on average than males (76 years vs. 73 years, p= <0.01) and were more likely to have chronic obstructive pulmonary disease (COPD; 38% versus 23%, p=0.01), require home oxygen therapy (9% versus 2%, p=0.04) or dialysis preoperatively (4% versus 0%, p=0.02). Distribution of other common vascular comorbidities was similar between the sexes. Thirty-day readmission was greater in females than males (18% versus 8%, p=0.02). Females had significantly lower survival at five years (48% ± 7.9% versus 65% ± 4.3%, p<0.01) and significantly lower one-year (89% ± 4.1% for females vs. 94% ± 1.7% for males, p=0.01) and five-year freedom from reintervention (69% ± 8.9% versus 84% ± 3.3%, p=0.02). On multivariable analysis, female sex (hazard ratio [HR]: 1.8, 95% confidence interval [CI]: 1.1-2.9), congestive heart failure (HR: 2.2, 95% CI: 1.2-3.9) and age (HR: 1.1, 95% CI: 1.0-1.1) were associated with 5-year mortality. Female sex remained as the only variable with a statistically significant association with five-year reintervention (HR: 2.4, 95% CI: 1.1-4.9).

CONCLUSIONS

Female sex was associated with decreased five-year survival and increased one and five-year reintervention following elective EVAR. Data from our institution suggests factors beyond patient age and baseline health risk likely contribute to greater surgical morbidity and mortality for females following elective EVAR.

Arterial Aneurysm Localization Is Sex-Dependent

The aim of this study was to investigate sex-dependent aneurysm distributions. A total of 3107 patients with arterial aneurysms were diagnosed from 2006 to 2016. Patients with anything other than true aneurysms, hereditary connective tissue disorders or vasculitides (n = 918) were excluded. Affected arterial sites and age at first aneurysm diagnosis were compared between women and men by an unpaired two-tailed t-test and Fisher’s exact test. The study sample consisted of 2189 patients, of whom 1873 were men (85.6%) and 316 women (14.4%) (ratio m:w = 5.9:1). Men had considerably more aneurysms in the abdominal aorta (83.4% vs. 71.1%; p < 0.001), common iliac artery (28.7% vs. 8.9%; p < 0.001), internal iliac artery (6.6% vs. 1.3%; p < 0.001) and popliteal artery (11.1% vs. 2.5%; p < 0.001). In contrast, women had a higher proportion of aneurysms in the ascending aorta (4.4% vs. 10.8%; p < 0.001), descending aorta (11.1% vs. 36.4%; p < 0.001), splenic artery (0.9% vs. 5.1%; p < 0.001) and renal artery (0.8% vs. 6.0%; p < 0.001). Age at disease onset and further aneurysm distribution showed no considerable difference. The infrarenal segment might be considered a natural border for aneurysm formation in men and women suspected to have distinct genetic, pathophysiologic and ontogenetic factors. Screening modalities for women at risk might need further adjustment, particularly thoracic cross-sectional imaging complementation.

Endothelial Dysfunction in the Pathogenesis of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA), defined as a focal dilation of the abdominal aorta beyond 50% of its normal diameter, is a common and potentially life-threatening vascular disease. The molecular and cellular mechanisms underlying AAA pathogenesis remain unclear. Healthy endothelial cells (ECs) play a critical role in maintaining vascular homeostasis by regulating vascular tone and maintaining an anti-inflammatory, anti-thrombotic local environment. Increasing evidence indicates that endothelial dysfunction is an early pathologic event in AAA formation, contributing to both oxidative stress and inflammation in the degenerating arterial wall. Recent studies utilizing single-cell RNA sequencing revealed heterogeneous EC sub-populations, as determined by their transcriptional profiles, in aortic aneurysm tissue. This review summarizes recent findings, including clinical evidence of endothelial dysfunction in AAA, the impact of biomechanical stress on EC in AAA, the role of endothelial nitric oxide synthase (eNOS) uncoupling in AAA, and EC heterogeneity in AAA. These studies help to improve our understanding of AAA pathogenesis and ultimately may lead to the generation of EC-targeted therapeutics to treat or prevent this deadly disease.

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.

Optimal timing of surveillance ultrasounds in small aortic aneurysms

OBJECTIVE

Small abdominal aortic aneurysms (AAA) surveillance intervals remain controversial and difficult to standardize. Current Society for Vascular Surgery guidelines lack quality evidence. The objective of this study is to examine patients followed in a high volume non-invasive vascular laboratory, determine if the current guidelines are fitting in clinical practice, and attempt to further identify risk factors for accelerated aneurysm growth.

METHODS

A retrospective analysis of patients who underwent at least two ultrasounds for AAA in the vascular laboratory during 2008-2018 with baseline diameter less than 5.0 cm was conducted. Patient demographics were collected. Groups were then created for comparison using the size criteria according to SVS guidelines. In addition, we compared overall growth rates specifically evaluating rapid growth (rate of at least 1.0 cm/year and size change of at least 0.5 cm from previous imaging), expected growth (any growth below 1.0 cm/year and of at least 0.5 cm from baseline) and no growth.

RESULTS

A total of 1581 patients (1232 male and 349 female) were identified with a total of 5945 ultrasound studies. The median age was 73 years and mean follow-up was 27.8 months. Baseline AAA size was 3.0-3.9 cm in 986 patients and 4.0-4.9 cm in 595 patients. The average maximum growth rate was 0.18 cm/year for AAAs 3.0-3.9 cm and 0.36 cm/year for AAAs 4.0-4.9 cm (p<0.001). Patients with AAA 4.0-4.9 cm at baseline were more likely to be white, male, hypertensive and have chronic kidney disease (p <0.05). 1078 patients (68.2%) demonstrated no growth over the observed time period with 342 patients (21.6%) demonstrating expected growth and 161 (10.2%) rapid growth. Male gender and baseline AAA size of 4.0-4.9 cm were more likely to demonstrate rapid growth (p=0.002) and eventual repair (p<0.001). Metformin use was more common in the AAA group with no growth (p <0.05). Freedom from rapid growth and repair indication at two years was significantly lower in those patients with baseline aneurysms 3.0-3.9 cm (p<0.001).

CONCLUSIONS

The overall low rate of events in small AAAs supports continued surveillance every 3 years for AAAs between 3.0 and 3.9 cm and yearly for male patients with AAAs 4.0-4.9 cm as recommended by the SVS Guidelines. Female gender may have less rapid growth than previously reported but likely merit more rigorous surveillance particularly as the AAAs approach 5.0 cm. Metformin use continues to demonstrate it may abrogate aneurysmal growth. Lastly, there is a subset of patients that exhibit more rapid growth of their small AAAs, and further study will be required to further classify these patients.

A Sinister Gut Feeling

Women are generally spared from abdominal aortic aneurysm (AAA) formation by the immunomodulating effects of estrogen. However, once they develop it, especially in the postmenopausal group, its behavior is more sinister with rapid expansion, a higher tendency to rupture, and higher mortality as compared to the male counterparts. Reported here is a case of AAA in a postmenopausal woman who came to the outpatient department with low backache, vague abdominal pain, and dysuria which initially gave a picture of pelvic inflammation with urinary tract infection but was later found out to be aortic aneurysm.

Female sex is independently associated with in-hospital mortality after endovascular aortic repair for ruptured aortic aneurysm

OBJECTIVE

Endovascular aortic repair (EVAR) can treat anatomically compatible ruptured abdominal aortic aneurysms (rAAA), but registry data suggests that women undergo more open abdominal aneurysm repairs than men. We evaluate in-hospital outcomes of EVAR for rAAA by sex.

METHODS

The Vascular Quality Initiative (VQI) registry was queried from 2013 to 2019 for rAAA patients treated with EVAR. Univariate analysis was performed with Student's t-test and chi-squared tests. Multivariable logistic regression was then performed to assess the association between female sex and inpatient mortality.

RESULTS

1775 patients were included (23.8% female). Female rAAA patients were older (p < 0.01) and weighed less (p < 0.01). They were less likely to have smoked (p <. 001) and had lower creatinine (1.29 vs 1.43, p <0.01) and hemoglobin (10.7 vs 11.7, p < 0.01). Women had smaller maximum aortic diameters (74 vs 66 mm, p < 0.01) and were less likely to have iliac aneurysms (p <.001). Women were more likely to have concomitant femoral endarterectomy (8.5% vs 4.6%, p=.03). Despite having no significant difference in complication or reintervention rates, women had higher rates of in-hospital mortality (45.9% vs 34.5%, p < 0.01). In a logistic regression model for predictors of in-hospital mortality (χ² < .01), increased age (OR 1.08, p < 0.01), female sex (OR 1.7, p=0.02), preoperative cardiac arrest (OR 5.29, p<0.01), concurrent iliac stenting (OR 2.38, p =0.02), postoperative mesenteric ischemia (OR 2.51, p<0.01) and postoperative transfusion (OR 1.06, p <0.01) were independently associated with in-hospital mortality. Increased preoperative hemoglobin was protective (OR 0.89, p < 0.01) CONCLUSIONS: Female sex is independently associated with in-hospital mortality after EVAR for rAAA, suggesting a relationship beyond anatomical, biochemical, and procedural covariates.

Prevalence of abdominal aortic aneurysms in patients with lung cancer

OBJECTIVE

Concomitance of abdominal aortic aneurysm (AAA) and primary lung cancer (LC) is not uncommon due to several shared risk factors. To evaluate the incidence of this association, analysis of the National Inpatient Sample database was utilized.

METHODS

A retrospective analysis of the National Inpatient Sample database between 2014 and 2018 for all patients diagnosed with primary LC was performed. The differences in the reported findings between the LC and control groups were assessed using the Pearson χ², Fisher exact, Student t, and/or Mann-Whitney U tests where appropriate. Multivariable logistic regression analysis was conducted to determine independent predictors of the presence of documented AAA.

RESULTS

A total of 158,904 patients were identified. Of these, 2430 patients (1.53%) were diagnosed with AAA and 156,474 (98.47%) without AAA. In the multivariable model, LC patients had higher odds of AAA compared with the general population (odds ratio, 1.43; 95% confidence interval, 1.35-1.51). In all age groups, female smokers had a higher rate of AAA compared with female nonsmokers (age <60 years, 0.13% vs 0.04%; 60-69 years, 0.77% vs 0.34%; 70-79 years, 1.65% vs 0.69%; and >80 years, 2.63% vs 1.31%; all P < .001).

CONCLUSIONS

LC and AAA share similar risk factors, which may explain the higher AAA prevalence among patients with LC. Given the higher prevalence of AAA in smokers compared with nonsmokers across all age groups in both male and female patients with LC, further sex-based studies investigating the overall mortality and morbidity benefits of AAA screening among patients with LC are highly warranted. This consideration would potentially address the sex disparity in outcomes for AAA management.

Sex Differences in Inflammation During Venous Remodeling of Arteriovenous Fistulae

Vascular disorders frequently have differing clinical presentations among women and men. Sex differences exist in vascular access for hemodialysis; women have reduced rates of arteriovenous fistula (AVF) maturation as well as fistula utilization compared with men. Inflammation is increasingly implicated in both clinical studies and animal models as a potent mechanism driving AVF maturation, especially in vessel dilation and wall thickening, that allows venous remodeling to the fistula environment to support hemodialysis. Sex differences have long been recognized in arterial remodeling and diseases, with men having increased cardiovascular events compared with pre-menopausal women. Many of these arterial diseases are driven by inflammation that is similar to the inflammation during AVF maturation. Improved understanding of sex differences in inflammation during vascular remodeling may suggest sex-specific vascular therapies to improve AVF success.

Sex-related disparities in intervention rates and type of intervention in patients with aortic and peripheral arterial diseases in the National Inpatient Sample Database

OBJECTIVE

The first annual Women's Vascular Summit highlighted sex- and gender-related knowledge gaps in vascular disease diagnosis and treatment. This finding suggests an opportunity for further research to improve care and outcomes in people who identify as women, specifically. The purpose of this study was to a large national dataset to identify all operations performed for abdominal aortic aneurysm (AAA), carotid artery stenosis (CAS), and peripheral arterial disease (PAD) in the United States, and to provide data on sex-related disparities in treatment.

METHODS

All hospitalizations of adult patients (≥18 years old) diagnosed with AAA, CAS, or PAD who underwent vascular surgery from 2000 to 2016 were identified in the Healthcare Cost and Utilization Project National Inpatient Sample. Sex-stratified U.S. Census data and sex-specific population disease prevalence estimates from the National Institute of Health and Agency for Healthcare Research and Quality were used to calculate the number of U.S. adults with AAA, CAS, and PAD. Sex-stratified rates of surgery and incidence rate ratios were estimated using Poisson regression. Among those undergoing surgery, multivariable logistic regression was used to assess differences in endovascular vs open approach.

RESULTS

Over 16 years, there were 1,021,684 hospitalizations for vascular surgery: 13% AAA (21% female, 79% male), 40% CAS (42% female, 58% male), and 47% PAD (42% female, 58% male). Females were older than males at time of surgery (median age, 71.3 years vs 69.7 years) and less likely to have private insurance (18% vs 23%); minimal differences were seen across race/ethnicity, comorbidities, and hospital characteristics. After accounting for disease prevalence, females were still 25% less likely to undergo surgery for AAA and 30% less likely to undergo surgery for PAD compared with males with the same disease. These results were consistent over time. After adjustment, females, compared with males, were less likely to receive an endovascular procedure compared with open for AAA or CAS, and more likely to receive one for PAD.

CONCLUSIONS

From 2000 to 2016 in the United States, females were less likely to undergo intervention for AAA and PAD than males. This finding is particularly significant for PAD, because the prevalence is the same for both sexes, indicating that females are likely undertreated for PAD. Additionally, females were less likely to undergo endovascular surgery for AAA and more likely to undergo endovascular surgery for PAD than males. These findings suggest that improvement in AAA and PAD identification and management in females may improve outcomes.

The Impact of Endograft Selection on Mid-Term Outcomes in Female Patients Following Endovascular Aortic Aneurysm Repair (EVAR) for Abdominal Aortic Aneurysm (AAA)

Background Abdominal aortic aneurysms (AAA) are far more common in male than female gender, although they appear to have a more aggressive pathophysiology in females. Given the lower incidence of AAA in females, it has been difficult to assess the impact of graft selection for endovascular aortic aneurysm repair (EVAR) in this cohort. Purpose To identify whether graft selection influences outcomes following AAA endoluminal repair in female patients. Methodology A retrospective analysis of published data for 711 female patients was conducted, collating data from three cohorts - Endurant Stent Graft Natural Selection Global post-market registry (ENGAGE), Global Registry for Endovascular Aortic Treatment (GREAT) and U.S. Zenith multicenter trial in combination with the Zenith female registry. Patients were recruited into the ENGAGE registry between 2009 and 2011, the GREAT registry between August 2010 and October 2016, and into the Zenith registry between 2000 and 2003. Patients from ENGAGE received the Medtronic Endurant stent graft for infrarenal AAA repair, patients analysed in GREAT received the Gore Excluder stent graft and the Zenith group received the Cook Zenith stent graft. Analyses were performed to evaluate all-cause mortality, aorta-related mortality, endoleak occurrence and surgical reintervention rates between the three cohorts. Results Of the 711 females, 133 were from ENGAGE (mean age 76 years), 538 were from GREAT (mean age 75 years) and 40 were from Zenith (mean age 74 years). The rates of co-morbidities between the three groups were broadly similar except for atherosclerotic disease which was more commonly observed in those treated with the GORE Excluder. The rate of endoleaks was lower when the Excluder stent was utilised as compared to the other two stents (Excluder 6.7% vs. Zenith 12.5% vs. Endurant 35.3%) even considering the limited follow-up of the Zenith group to two years as compared to five years for both ENGAGE and GREAT. All-cause mortality was similar in all three groups across the period examined while aorta-related mortality was uncommon. Reintervention rate was 15% at two years following the utilisation of the Zenith aortic graft while the rate of intervention at five years was broadly similar between ENGAGE and GREAT. Conclusion The newer generation, lower profile aortic endografts appear to have provided a safe and successful tool in the management of AAA in female patients, despite more complex aortic anatomy with shorter infrarenal neck length and larger aortic neck angulation.

Aortic aneurysms and dissections: Unmet needs from physicians and engineers perspectives

The treatment of aortic disease is complex, requiring cardiothoracic and vascular surgeons to make pre-, post- and intraoperative decisions directly influencing patient survival and well-being. Despite tremendous advancement in vascular surgery and endovascular techniques in the last two decades, along with the abundance of research in the field, many unmet needs and unanswered questions remain. Tight collaboration between engineers and physicians is a keystone in translating new tools, techniques, and devices into practice. Here, we have gathered our perspective, as physicians and engineers, in several pressing issues associated with the diagnosis and treatment of aortic aneurysms and dissection, referring to the current knowledge and practice, signifying unmet needs as well as future directions.

Sex Differences in Rupture Risk and Mortality in Untreated Patients With Intact Abdominal Aortic Aneurysms

Background

Studies on intact abdominal aortic aneurysms mainly focus on treated patients, and data on untreated patients are sparse. The objective was to investigate sex differences among untreated patients regarding rupture and mortality rates and to determine predictors for these events. Sex‐specific causes of death were evaluated.

Methods and Results

All patients ≥40 years diagnosed from 2001 to 2015 (n=32 393) with intact abdominal aortic aneurysms were identified in national registries; 60% (n=19 569) were untreated. Comorbid loads, crude rupture, and mortality rates were assessed. Predictors of 5‐year rupture and mortality were analyzed in Cox models (sex, age, comorbidities, income, and marital status). The proportion of men and women with multiple comorbidities was similar. Within 5 years, 798 ruptures occurred (9.7% women versus 6.9% men, P<0.001). Ruptures were independently predicted by female sex (hazard ratio [HR], 1.23; 95% CI, 1.07–1.42; P=0.004), chronic obstructive pulmonary disease (HR, 1.36; 95% CI, 1.15–1.62; P<0.001), age (HR, 11.49; 95% CI, 5.68–23.25 for ≥80 years; P<0.001), and income (HR, 0.63; 95% CI, 0.53–0.75 for highest tertile; P<0.001). After 5 years, 56.5% women and 50.4% men were deceased. Mortality was not independently predicted by female sex. Rupture was the third most common cause of death (11.9% women versus 8.7% men; P<0.001). The median time‐to‐events was 2.8 years.

Conclusions

A considerable proportion of patients with intact abdominal aortic aneurysms in surveillance remain untreated. Despite surveillance algorithms, the healthcare system fails to prevent a high number of ruptures, especially among women. The time‐to‐event data highlight the urgency to develop more individualized surveillance.

A Novel Hypothesis: A Role for Follicle Stimulating Hormone in Abdominal Aortic Aneurysm Development in Postmenopausal Women

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta, which can potentially be fatal due to exsanguination following rupture. Although AAA is less prevalent in women, women with AAA have a more severe AAA progression compared to men as reflected by enhanced aneurysm growth rates and a higher rupture risk. Women are diagnosed with AAA at an older age than men, and in line with increased osteoporosis and cardiovascular events, the delayed AAA onset has been attributed to the reduction of the protective effect of oestrogens during the menopausal transition. However, new insights have shown that a high follicle stimulating hormone (FSH) level during menopause may also play a key role in those diseases. In this report we hypothesize that FSH may aggravate AAA development and progression in postmenopausal women via a direct and/or indirect role, promoting aorta pathology. Since FSH receptors (FSHR) are reported on many other cell types than granulosa cells in the ovaries, it is feasible that FSH stimulation of FSHR-bearing cells such as aortic endothelial cells or inflammatory cells, could promote AAA formation directly. Indirectly, AAA progression may be influenced by an FSH-mediated increase in osteoporosis, which is associated with aortic calcification. Also, an FSH-mediated decrease in cholesterol uptake by the liver and an increase in cholesterol biosynthesis will increase the cholesterol level in the circulation, and subsequently promote aortic atherosclerosis and inflammation. Lastly, FSH-induced adipogenesis may lead to obesity-mediated dysfunction of the microvasculature of the aorta and/or modulation of the periaortic adipose tissue. Thus the long term increased plasma FSH levels during the menopausal transition may contribute to enhanced AAA disease in menopausal women and could be a potential novel target for treatment to lower AAA-related events in women.

Global Burden of Cardiovascular Diseases and Risk Factors, 1990-2019: Update From the GBD 2019 Study

Cardiovascular diseases (CVDs), principally ischemic heart disease (IHD) and stroke, are the leading cause of global mortality and a major contributor to disability. This paper reviews the magnitude of total CVD burden, including 13 underlying causes of cardiovascular death and 9 related risk factors, using estimates from the Global Burden of Disease (GBD) Study 2019. GBD, an ongoing multinational collaboration to provide comparable and consistent estimates of population health over time, used all available population-level data sources on incidence, prevalence, case fatality, mortality, and health risks to produce estimates for 204 countries and territories from 1990 to 2019. Prevalent cases of total CVD nearly doubled from 271 million (95% uncertainty interval [UI]: 257 to 285 million) in 1990 to 523 million (95% UI: 497 to 550 million) in 2019, and the number of CVD deaths steadily increased from 12.1 million (95% UI:11.4 to 12.6 million) in 1990, reaching 18.6 million (95% UI: 17.1 to 19.7 million) in 2019. The global trends for disability-adjusted life years (DALYs) and years of life lost also increased significantly, and years lived with disability doubled from 17.7 million (95% UI: 12.9 to 22.5 million) to 34.4 million (95% UI:24.9 to 43.6 million) over that period. The total number of DALYs due to IHD has risen steadily since 1990, reaching 182 million (95% UI: 170 to 194 million) DALYs, 9.14 million (95% UI: 8.40 to 9.74 million) deaths in the year 2019, and 197 million (95% UI: 178 to 220 million) prevalent cases of IHD in 2019. The total number of DALYs due to stroke has risen steadily since 1990, reaching 143 million (95% UI: 133 to 153 million) DALYs, 6.55 million (95% UI: 6.00 to 7.02 million) deaths in the year 2019, and 101 million (95% UI: 93.2 to 111 million) prevalent cases of stroke in 2019. Cardiovascular diseases remain the leading cause of disease burden in the world. CVD burden continues its decades-long rise for almost all countries outside high-income countries, and alarmingly, the age-standardized rate of CVD has begun to rise in some locations where it was previously declining in high-income countries. There is an urgent need to focus on implementing existing cost-effective policies and interventions if the world is to meet the targets for Sustainable Development Goal 3 and achieve a 30% reduction in premature mortality due to noncommunicable diseases.

Female Sex Portends Worse Long-Term Survival after Open Type I-III Thoracoabdominal Aneurysm Repair

BACKGROUND

Although outcomes after infrarenal abdominal aortic aneurysm surgery are worse in females, sex-specific differences in outcomes after open thoracoabdominal aortic aneurysm (TAAA) repair are less clear. The goal of this study was to identify sex-based disparities in short- and long-term outcomes after open type I-III TAAA surgery.

METHODS

All open type I-III TAAA repairs performed from 1987 to 2015 were evaluated using an institutional database. Charts were retrospectively evaluated for perioperative outcomes: major adverse events (MAEs), in-hospital death, and long-term survival. Univariate analysis was performed using the Fisher's exact test for categorical variables and the Wilcoxon rank-sum test for continuous variables. Logistic regression was used for in-hospital end points; survival analyses were performed with Cox proportional hazards modeling and Kaplan-Meier techniques. Sensitivity analyses were performed for relevant multivariable models, one with ruptures removed and another evaluating only repairs performed before 2006 to account for any selection bias due to wider use of complex endovascular technology.

RESULTS

Five-hundred sixteen patients underwent open type I-III TAAA repair during the study period. Females accounted for 54.3% (n = 280) of the cohort. Women were older, less likely to have a chronic dissection etiology, more likely to present with a symptomatic/ruptured lesion, and had a lower admission creatinine than men. Perioperative death occurred in 23 men (9.8%) and 19 women (6.8%) (P = 0.26); 133 women (47.3%) and 116 men (49.2%) suffered an MAE (P = 0.72). Multivariable analyses revealed no sex-based difference in perioperative death (Female sex adjusted odds ratio (AOR): 0.72, 95% confidence interval (CI): 0.4-1.4, P = 0.34) or MAE (AOR: 1.0 CI: 0.7-1.5, P = 0.82). Unadjusted survival at five years was 50% for women and 67% for men (log-rank P < 0.001). Female sex was an independent predictor of decreased survival (hazard ratio (HR): 1.5 95% CI: 1.2-1.9, P = 0.001) when adjusted for age, aneurysm extent, creatinine, chronic obstructive pulmonary disease, and ruptures. After removing all ruptures, female sex remained nonpredictive of perioperative death (AOR: 1.1, 95% CI 0.5-2.5, P = 0.75) or MAE (AOR: 1.2, CI: 0.8-1.9, P = 0.31) and predictive of decreased long-term survival (HR: 1.5, 95% CI: 1.2-2.0, P = 0.001).

CONCLUSIONS

Those undergoing open type I-III TAAA repair have similar rates of perioperative mortality and MAEs, regardless of sex. However, female sex is an independent risk factor for decreased long-term survival.

The fate of patients with large abdominal aortic aneurysms referred for consideration for elective repair

BACKGROUND

The premise of the Vascular Services Quality Improvement Programme (VSQIP) in management of patients with asymptomatic large abdominal aortic aneurysms (AAA) is reducing mortality from ruptured AAA in a sustainable way without introducing excessive procedure related mortality. Inevitably a proportion of patients are deemed unfit for elective repair. The aim of this study was to report outcomes of patients who were referred with large asymptomatic AAAs including those turned down for elective repair and identify independent risk factors for being turned down for elective open or endovascular repair of AAA.

METHODS

Consecutive patients referred to a regional vascular center with a large AAA (greater than 55 mm) between 1^st January 2008 and 31^st March 2018 were included. All patients underwent the nationally agreed VSQIP pathway which included preoperative cardio-pulmonary exercise testing and contrast enhanced CT scan of aorta. The decision to repair and the modality of repair were made through a Multi-Disciplinary Team MDT process on each patient. Patients were classified into two groups; those managed non-operatively and those offered elective repair. Survival was assessed using Kaplan-Meier analysis. Factors associated with non-operative management were examined using multivariate analysis.

RESULTS

A total of 876 patients of whom 768 were men and 108 were women with a mean age of 74 years (SD: 7.2) and a diagnosis of a large asymptomatic AAA were assessed. One hundred and seventy-four patients (19.9%) were turned down for elective repair and 702 (80.1%) underwent repair [Open: 244(34.8%), EVAR: 458 (65.2%] with perioperative and 30 day mortality of 1.13% (8 patients). Median duration of follow-up was 1530 days (51 months), (inter quartile range: 1714 days). Patients who underwent repair had significantly higher survival rates compared with those who were turned down (P<0.0001). Risk factors for being turned down for elective AAA included anaerobic threshold <8 mL kg^-1 min^-1 [OR: (95% CI): 2.27 (1.31-3.92)], (P=0.0005), Age>80 yrs. [OR (95% CI): 1.32 (1.012-1.52], (P=0.0203), complex aneurysm morphology [OR (95% CI): 3.70 (2.82-4.87], (P<0.0001), Female gender: [OR: (95% CI): 2.41 (1.32-3.92)], (P<0.0001) and being classed high or very high risk for open AAA repair OR: (95% CI): 6.48 (4.01-10.49)], (P<0.0001).

CONCLUSIONS

A significant cohort of patients with large asymptomatic AAA is turned down for elective AAA repair. These patients appear to have significantly lower survival rates than those who are treated. Information on patients turned down for elective AAA repair should be routinely reported.

Sex-related outcomes after open type IV thoracoabdominal aortic aneurysm repair

OBJECTIVE

Although outcomes after infrarenal abdominal aortic aneurysm surgery are worse in women, sex-specific differences in outcomes after open type IV thoracoabdominal aortic aneurysm (TAAA) surgery are undefined. The goal of this study was to define sex-based disparities in short- and long-term outcomes after open type IV TAAA surgery.

METHODS

All open type IV TAAA repairs performed during 27 years were evaluated using a single institutional database. Charts were retrospectively evaluated for major adverse events (in-hospital death, other major in-hospital complication) and long-term complications (graft- and aortic-related events and death). Univariate analyses were performed using the Fisher's exact test for categorical variables and Wilcoxon rank-sum testing for continuous variables. Logistic multivariable regression was used for the in-hospital end points death and major complication, and survival analyses were performed with Cox proportional hazards modeling and Kaplan-Meier techniques.

RESULTS

During the 27-year study period, 234 patients had an open type IV TAAA repair; 85 were female and 149 were male. There were 26 (17.5%) men and 16 (18.8%) women who suffered a major in-hospital complication/death. There were eight (3.4%) in-hospital deaths, all occurring in men. Unadjusted survival at 5 years was 67.9% for women and 58.4% for men. Multivariable analyses revealed no sex-based difference in combined major in-hospital events and death (female: odds ratio [OR], 1.8; confidence interval [CI], 0.83-4.0; P = .13) or any complication (OR, 1.0; CI, 0.55-1.8; P = .99). However, women were less likely than men to be discharged to home (OR, 0.28; CI, 0.13-0.60; P = .001) and had decreased survival compared with men after discharge (hazard ratio, 2.1; CI, 1.2-3.5; P = .008).

CONCLUSIONS

No sex-based differences were found for the in-hospital outcomes of death or major complication after open type IV TAAA repair. However, women are less likely than men to be discharged home. Among those who survive the index operation, female sex portends decreased survival following discharge after repair.

Is gender still a risk factor for mortality in patients who undergo elective repair of abdominal aortic aneurysms? Experience of a single center

BACKGROUND

Vascular Services Quality Improvement Program (VSQIP) was introduced to reduce mortality from elective repair of AAA in the UK. This study examines the differences in perioperative mortality and postoperative survival between men and women following elective repair of AAAs in the 10 years after implementation of the (VSQIP).

METHODS

Consecutive patients who underwent elective repair of AAA between 1^st January 2008 and 31^st March 2018 were included. All patients were assessed using the nationally agreed VSQIP pathway which involved cardiopulmonary exercise testing as well as contrast enhanced CT scan of aorta and multidisciplinary assessment to plan each treatment. CT scans were examined to assess the morphology of AAA. Patients were stratified by age, gender, AAA morphology and preoperative anaerobic threshold. Postoperative survival was assessed using Kaplan-Meier analysis. Cox regression analysis was used to determine predictors of postoperative mortality.

RESULTS

A total of 702 patients underwent elective repair of AAA of whom 632 were men and 70 were women. The mean age of study cohort was 73.5±7.3 years and mean AAA diameter was 62±9.9 mm. Two hundred and forty-four patients underwent open repair, 402 underwent infrarenal endovascular aneurysm repair (EVAR) and 56 underwent complex EVAR with perioperative and 30-day mortality of 1.13%. No significant difference was observed in perioperative/30-day mortality between men and women (χ²=0.06, P=0.81). Anaerobic threshold <8 (HR=0.68 [95% CI: 0.51-0.92]), complex aneurysm morphology (HR=1.7 [95% CI: 1.39-2.19]) risk category (HR=1.89 [95% CI: 1.48-2.42]) and patients age (HR=1.41 [95% CI: 1.13-1.89]) were independent risk factor for mortality following repair of AAA, whilst female gender (HR=0.89 [95% CI: 0.54-1.48]) and AAA size (HR=1.01 [95% CI: 0.84-1.22]) were not. There was no difference in postoperative survival between men and women who underwent elective repair of AAA (Log rank: 1.82, P=0.61).

CONCLUSIONS

Following the implementation of VSQIP female gender is no longer a significant risk factor for perioperative mortality or reduced survival following elective repair of large asymptomatic AAA.

Multicentre Covariate Adjustment Analysis of Short-Term and 5-Year Outcomes after Endovascular Repair according to Sex

Background

Several studies have reported worse outcomes in women compared to men after endovascular aneurysm repair (EVAR). This study aimed to evaluate sex-specific short-term and 5-year outcomes after EVAR.

Methods

A total of 409 consecutive patients underwent elective EVAR from 2004 to 2017 at two tertiary hospitals in Western Australia. Baseline, intraoperative, and postoperative variables were examined retrospectively according to sex. The primary outcome was 30-day mortality (death within 30 days after EVAR). Secondary outcomes were 30-day composite endpoint, length of stay after EVAR, 5-year survival, freedom from reintervention, residual aneurysm size after EVAR, and major adverse event rate at 5-year follow-up.

Results

A cohort of 409 patients, comprising 57 women (14%) and 352 men (86%), was analysed. Female patients were older (median age, 76.8 versus 73.5 years, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%, p=0.017). Male patients were more likely to be past smokers (40.9% versus 22.8%.

Conclusion

This study found no significant differences in 30-day and 5-year outcomes between female and male patients treated with EVAR, implying that EVAR remains a safe treatment choice for female patients.

Sex-Related Outcomes After Endovascular Aneurysm Repair Within the Global Registry for Endovascular Aortic Treatment

BACKGROUND

Abdominal aortic aneurysms (AAAs) are more common in men. However, women have been shown to have more short- and long-term adverse outcomes after endovascular aneurysm repair. This disparity is thought to be multifactorial, including anatomical differences, hormonal differences, older age of presentation, and a greater degree of preoperative comorbidities.

METHODS

A retrospective analysis that included data for 3,758 patients from the Global Registry for Endovascular Aortic Treatment (GREAT) was conducted. Patients were recruited into GREAT between August 2010 and October 2016 and received the Gore Excluder stent graft for infrarenal AAAs repair. Cox multivariate regression analyses were performed to analyze any reintervention and device-related intervention rates.

RESULTS

Of the 3,758 patients, 3,220 were male (mean age 73 years) and 538 were female (mean age 75 years). Women had higher prevalence rates of chronic obstructive pulmonary disease (P < 0.0001) and renal insufficiency (P = 0.03), whereas men had higher rates of cardiovascular comorbidities. The AAAs in women were smaller in diameter with shorter and more angulated necks. Women did not experience a significantly higher rate of endoleaks but did exhibit higher reintervention rates, including reintervention for device-related issues. In terms of mortality, aorta-related mortality was most prevalent within the first 30 days after procedure in both sexes.

CONCLUSIONS

Women were treated at an older age and had a more hostile aneurysmal anatomy. Although the mortality rates were lower in women, they had significantly higher rates of reintervention, and thus higher morbidity rates after endovascular aneurysm repair.

Sex Disparity in Outcomes of Ruptured Abdominal Aortic Aneurysm Repair Driven by In-hospital Treatment Delays

OBJECTIVE

We sought to assess whether sex-related differences in timely repair of ruptured abdominal aortic aneurysm (rAAA) were associated with excess risk of early mortality in women.

SUMMARY BACKGROUND DATA

rAAA is a surgical emergency and timeliness of intervention affects outcomes. A door-to-intervention time of <90 minutes is recommended.

METHODS

All rAAA repairs in the Vascular Quality Initiative from 2003 to 2017 were reviewed. Patients were stratified by sex and time-delay cohorts. Univariate and multivariate analyses were performed.

RESULTS

There were 3719 rAAA repairs, of which 797 (21%) were performed in women. Sex did not affect repair type: open versus endovascular (21% females, each). Despite similar presentation delays [median 6 hours (inter quartile range, IQR: 3-16)], admission-to-intervention time was longer for women than men [median 1.5 hours (IQR 1-4] vs 1.2 hours (IQR 1-3), P=0.047]. Overall, 45% of patients had a >90-minute delay from admission to repair, with more women than men experiencing this delay (49% vs 44%, P=0.01). Neither were more likely to undergo transfer for treatment. After risk adjustment, female sex was associated with a 48% increase in 30-day mortality. Sex differences in mortality were no longer observed in patients with intervention delays of ≤90 minutes. In patients with >90-minute delays, a 77% increase in 30-day mortality of women over men was noted.

CONCLUSIONS

Nearly half of rAAA patients have a door-to-intervention time longer than recommended societal guidelines. Sex differences in mortality after rAAA repair seem to be driven by in-hospital treatment delays.

Nuclear receptors in abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) pose a considerable health burden and at present are only managed surgically since there is no proven pharmacotherapy that will retard their expansion or reduce the incidence of fatal rupture. This pathology shares several pathophysiological mechanisms with atherosclerosis, such as macrophage infiltration, inflammation, and degradation of extracellular matrix. Therefore, therapeutic targets proven effective in the treatment of atherosclerosis could also be considered for treatment of AAA. Different members of the nuclear receptor (NR) superfamily have been extensively studied as potential targets in the treatment of cardiovascular disease (CVD) and therefore might also be suited for AAA treatment. In this context, this review summarizes the role of different NRs in CVD, mostly atherosclerosis, and discusses in detail the current knowledge of their implications in AAA. From this overview it becomes apparent that NRs that were attributed a beneficial or adverse role in CVD have similar roles in AAA. Together, this overview provides compelling evidence to consider several NRs as attractive targets for future treatment of AAA.

LUCY results show females have equivalent outcomes to males following endovascular abdominal aortic aneurysm repair despite more complex aortic morphology

OBJECTIVE

Females remain underrepresented in studies of endovascular aneurysm repair (EVAR) owing to anatomic ineligibility for EVAR devices. The aim of the LUCY study is to explore the comparative safety and effectiveness of EVAR using a low-profile stent graft (Ovation; Endologix, Inc, Irvine, Calif) in females as well as males.

METHODS

The LUCY registry was a prospective, nonrandomized, multicenter study where patient enrollment was stratified by sex in a two-to-one ratio (male-to-female). Main outcomes were procedural data, 30-day major adverse events, device-related adverse events confirmed with contrast-enhanced computed tomography scans, secondary interventions, and hospital readmissions. Adverse events were adjudicated by a clinical events committee. Patients were followed at their 1-month and 1-year follow-up visits.

RESULTS

A total of 225 patients (76 females, 149 males) were enrolled at 39 U.S. centers. No statistically significant sex differences were observed in demographics or medical history. Females presented with smaller access vessels (6.2 vs 7.7 mm; P < .001), statistically smaller neck diameter (22 mm vs 23 mm; P = .001), similar neck angulation (11% vs 9% angulation >45°; P = .81), and smaller maximum abdominal aortic aneurysm (AAA) diameter (50 mm vs 53 mm; P = .01), however, these factors do not seem to be clinically significant. Technical success was 99%, and the median hospital stay was 1 day. The incidence of MAE through 30 days was 1.3% in females and 2.0% in males. There were no differences between sexes observed among the 30-day perioperative outcomes. The 30-day secondary intervention rate was 0.4%. The all-cause readmission rate through 30 days was 5.3% in females and 6.7% in males. There were no reports of limb occlusion or deaths within the first 30 days. At 1 year, there were no deaths in the female arm but nine deaths (6.0%) were observed in males, two of which were AAA related (1.3%). Through 1 year, there were eight type IA endoleaks (one female, seven males; P = .27) and three cases with limb occlusion (one female, two males). There were no reports of migration, AAA rupture, or surgical conversion through the end of follow-up.

CONCLUSIONS

Despite more complex aortic morphology in females than males, EVAR with a low-profile stent graft was associated with comparable procedural and perioperative outcomes through 1 year between the sexes.

Ovariectomy increases the incidence and diameter of abdominal aortic aneurysm in a hypoperfusion-induced abdominal aortic aneurysm animal model

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by weakening of the vascular walls. Male sex is a risk factor for AAA, and peak AAA incidence occurs in men 10 years earlier than in women. However, the growth rate of AAA is faster in women, and women have a higher mortality due to AAA rupture. The mechanisms underlying sex-related differences in AAA remain unknown. Herein, we evaluated the effects of ovariectomy (OVX) on AAA in rats. Upon evaluation of the effects of OVX and AAA induction, AAA incidence rate and the aneurysm diameter increased in the OVX group. However, the histopathology in the developed AAA wall was not different between groups. When the effects of OVX on the vascular wall without AAA induction were evaluated, elastin and collagen levels were significantly decreased. Furthermore, the level of matrix metalloproteinase-9 significantly increased in the OVX group. According to our results, it is speculated that decreased levels of collagen and elastin fibers induced by OVX might be involved in increased incidence rate and diameter of AAA. Weakening of the vascular wall before the onset of AAA might be one reason for the faster rate of AAA growth in women.

Impact of Gender on Outcomes Following Abdominal Aortic Aneurysm Repair

Objective:

The purpose of this study is to use a large, nationally representative vascular database to assess differences in patient characteristics, aortic neck anatomy, and outcomes between men and women following open (open aneurysm repair [OAR]) and endovascular (endovascular aneurysm repair [EVAR]) abdominal aortic aneurysm (AAA) repair.

Methods:

Patients undergoing AAA repair from 2003 to 2018 in Vascular Quality Initiative were identified and stratified by procedure (EVAR vs OAR). Thirty-day mortality and major in-hospital complications were assessed between genders within each operative cohort. An EVAR subset analysis was performed to assess differences in aortic neck anatomy; hostile neck anatomy was defined as length <15 mm (L < 15), angle >60° (A > 60), and/or diameter >28 mm (D > 28). Standard univariate and multivariable analyses were performed.

Results:

A total of 50 213 patients were identified: 9263 (19%) OAR and 40 950 (82%) EVAR. In both cohorts, majority of patients were men (OAR 73% and EVAR 81%). Women were more likely to have a hostile neck (31.7% vs 24.1%, P < .001), L < 15 (19.8% vs 11.9%, P < .001), and A > 60 (11.5% vs 5.4%, P < .001). Men had larger aneurysm (mean, 57 vs 55 mm, P < .001) and were more likely to have D > 28 (14.0% vs 10.6%, P < .001). Women undergoing EVAR were more likely to undergo aortic extensions (21.9% vs 16.0%) and receive higher contrast volume. After adjusting for potential confounders, female gender was associated with 86% and 50% increased risk of 30-day mortality in OAR and EVAR, respectively. Women were more likely than men to experience renal, cardiac, and pulmonary complications only in the EVAR cohort. Women had a 2-fold increased odds of developing type 1 endoleak.

Conclusion:

Our study demonstrates unfavorable neck anatomy occurs more frequently in women compared to men. Women were also at an increased risk of developing major complications, particularly following EVAR. Careful patient selection is indicated in all patients to reduce complications, with special attention in women with hostile neck.

Gender differences in outcomes after aortic aneurysm surgery should foster further research to improve screening and prevention programmes

Background Gender-related biases in outcomes after thoracic aortic surgery are an important factor to consider in the prevention of potential complications related to aortic diseases and in the analysis of surgical results. Methods The aim of this study is to provide an up-to-date review of gender-related differences in the epidemiology, specific risk factors, outcome, and screening and prevention programmes in aortic aneurysms. Results Female patients affected by aortic disease still have worse outcomes and higher early and late mortality than men. It is difficult to plan new specific strategies to improve outcomes in women undergoing major aortic surgery, given that the true explanations for their poorer outcomes are as yet not clearly identified. Some authors recommend further investigation of hormonal or molecular explanations for the sex differences in aortic disease. Others stress the need for quality improvement projects to quantify the preoperative risk in high-risk populations using non-invasive tests such as cardiopulmonary exercise testing. Conclusions The treatment of patients classified as high risk could thus be optimised before surgery becomes necessary by means of numerous strategies, such as the administration of high-dose statin therapy, antiplatelet treatment, optimal control of hypertension, lifestyle improvement with smoking cessation, weight loss and careful control of diabetes. Future efforts are needed to understand better the gender differences in the diagnosis, management and outcome of aortic aneurysm disease, and for appropriate and modern management of female patients.

Cerebral Aneurysms Differ in Patients with Hysterectomies

OBJECTIVE

Female sex is a well-known risk factor for aneurysm formation. Although the role of the ovaries and estrogen in aneurysm development has been supported, other organ-hormone pairs unique between sexes also may be implicated. In this study, we aimed to determine whether intracranial aneurysms microsurgically clipped in patients with previous hysterectomies exhibit any unique aneurysm characteristics from those without hysterectomies.

METHODS

Solitary aneurysms microsurgically treated by the senior author (M.T.L.) were included from a database of patients treated between January 2010 and April 2013 at a tertiary academic medical center. Only female patients and patients equal or older in age to the youngest patient in the hysterectomy group were included in the control group. Patient and aneurysm characteristics were compared using the χ² test for categorical variables and the independent t test analysis for continuous variables.

RESULTS

A total 233 patients were included in the study. Forty-three patients (19%) had undergone a previous hysterectomy; none had oophorectomies recorded. No difference in mean age (P = 0.89), hypertension (P = 0.38), alcohol use (P = 0.87), tobacco use (P = 0.22), or aneurysm location (P = 1) existed. However, patients in the hysterectomy group more often presented in a good neurologic condition before surgery (88% vs. 74%, P = 0.04) and had fewer large aneurysms (8% vs. 24%, P = 0.03). Also, fewer presented with a ruptured aneurysm (28%) then the nonhysterectomy group (51%) (P = 0.004).

CONCLUSIONS

Female patients with a surgical history of a hysterectomy have a lower rate of large aneurysms, present in better neurologic condition, and are less likely to present with a ruptured aneurysm than females without a hysterectomy.

Should Abdominal Aortic Aneurysms in Women be Repaired at a Lower Diameter Threshold?

Abdominal aortic aneurysm (AAA) primarily affects male patients; however, female patients with AAA have a faster rate of aneurysm growth, have higher risk of rupture even at smaller diameters, and have worse outcomes following repair of ruptured and intact aneurysms. Furthermore, early natural history studies and randomized controlled trials evaluating surveillance versus repair in small aneurysms were conducted primarily in male patients. Therefore, there are limited data regarding the ideal threshold for elective repair of AAA in women, either by aortic diameter or by alternative measures. We review the existing literature regarding AAA in women and consider the most appropriate threshold for repair.

Epidemiology and contemporary management of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.

Sex-dependent outcomes following elective endovascular aortic repair

BACKGROUND

Evidence has shown that women derive less benefit from endovascular aortic repair (EVAR) in large part due to more challenging aortoiliac anatomy. This study sought to examine whether sex-dependent outcomes exist following elective EVAR cases.

METHODS

An institutional retrospective review was performed on patients who underwent elective EVAR procedures between 2008 and 2014. Outcome data collected included procedural and hospital morbidity, mortality, and overall EVAR durability based on the incidence of unplanned graft-related secondary interventions (SIs) (e.g., open conversion, proximal or distal extensions, and coil embolizations).

RESULTS

One hundred eighty-one patients (150 men, 31 women) met the study inclusion criteria. Median follow-up was 40.3 mo. Women had more challenging anatomy compared to men including smaller overall iliac diameters (6.8 mm versus 8.0 mm, P < 0.001) and more severe iliac angulation (77% moderate to severe versus 44%, P < 0.001). Women had increased risk of postoperative complications compared to men (41.9% versus 11.3%, P = 0.003). There was no perioperative mortality in our series of elective EVAR cases. Median 5-y survival following EVAR was 64.4% for men and 76.3% for women (P = 0.599). Late SI rates following EVAR was 10.5% with 16 (10.7%) men and 3 (9.7%) women needing interventions (P = 0.870). Overall durability of EVAR extrapolated as time to SIs was 91% at 2 y and 85% at 5 y. Factors predisposing SIs were iliac tortuosity (P = 0.046), aortic neck angle (P = 0.022), and endoleak at the follow-up (P = 0.030).

CONCLUSIONS

In this study, immediate outcomes following EVAR were different between men and women, with women having increased rates of postoperative complications. Mortality and overall long-term durability of EVAR, however, were the same between sexes despite anatomical differences. EVAR durability was significantly dependent on the severity of iliac tortuosity, aortic neck angulation, and presence of endoleak at the follow-up.