Racial and sex disparities in inpatient outcomes of patients with ruptured abdominal aortic aneurysms in the United States

BACKGROUND

Ruptured abdominal aortic aneurysm (AAA) is a medical emergency that requires immediate surgical intervention. The aim of this analysis was to identify the sex- and race-specific disparities that exist in outcomes of patients hospitalized with this condition in the United States using the National Inpatient Sample (NIS) to identify targets for improvement and support of specific patient populations.

METHODS

In this descriptive, retrospective study, we analyzed the patients admitted with a primary diagnosis of ruptured AAA between January 1, 2016, and December 31, 2020, using the NIS database. We compared demographics, comorbidities, and in-hospital outcomes in AAA patients, and compared these results between different racial groups and sexes.

RESULTS

A total of 22,395 patients with ruptured AAA were included for analysis. Of these, 16,125 patients (72.0%) were male, and 6270 were female (28.0%). The majority of patients (18,655 [83.3%]) identified as Caucasian, with the remaining patients identifying as African American (1555 [6.9%]), Hispanic (1095 [4.9%]), Asian or Pacific Islander (470 [2.1%]), or Native American (80 [0.5%]). Females had a higher risk of mortality than males (OR, 1.7; 95% confidence interval [CI], 1.45-1.96; P < .001) and were less likely to undergo endovascular aortic repair (OR, 0.70; 95% CI, 0.61-0.81; P < .001) or fenestrated endovascular aortic repair (OR, 0.71; 95% CI, 0.55-0.91; P = .007). Relative to Caucasian race, patients who identified as African American had a lower risk of inpatient mortality (OR, 0.50; 95% CI, 0.37-0.68; P < .001).

CONCLUSIONS

In this retrospective study of the NIS database from 2016 to 2020, females were less likely to undergo endovascular intervention and more likely to die during their initial hospitalization. African American patients had lower rates in-hospital mortality than Caucasian patients, despite a higher burden of comorbidities. Future studies are needed to elucidate the potential factors affecting racial and sex disparities in ruptured AAA outcomes, including screening practices, rupture risk stratification, and more personalized guidelines for both elective and emergent intervention.

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.

Gender Influence on Abdominal Aortic Aneurysm Surgery in a Caribbean Population

Female patients with abdominal aortic aneurysms (AAAs) are usually less common and older than their male counterparts. We report on AAA disease in a Caribbean nation with respect to gender and review their outcomes relative to the male population. Data were collected prospectively and analyzed retrospectively for patients with AAAs who underwent surgery from 2001 to 2018. Sixty patients were diagnosed with AAA with 44 going on to have surgical repair of which 35 were males, aged 61 to 89 (mean age 73.4 years). Nine women ages 44 to 74 years (mean age 60.8 years) had surgical intervention, three being between 40 and 49 years. The size of aneurysms in these patients ranged from 4.3 to 11.0 cm in diameter (average 6.95 cm), female patients having an average diameter of 6.7 cm. Of the 44 patients, 43 underwent open and one endovascular repair. Thirty-three were elective cases and 11 were ruptured with 32 aorto-aortic and 13 aorto-iliac repairs. There were nine fatalities, three elective and six ruptured, with only one being female. Women had similar outcomes to men in all age groups with young patients having good results. Female AAA patients are usually older, undergo less surgical procedures especially if endovascular, and have worse outcomes than their male counterparts. Our study showed that the females were younger but had similar outcomes to the male patients. The female Caribbean patients may present at much younger ages than in continental populations and this may be due to genetic, ethnic, or lifestyle factors.

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.

Screening for Abdominal Aortic Aneurysms and Risk Factors in 65-Year-Old Men in Oslo, Norway

Purpose

To investigate the prevalence of and risk factors for abdominal aortic aneurysm (AAA) in 65-year-old men in Oslo, Norway.

Materials and Methods

From May 2011, until September 2019, the annual population of 65-year-old men living in Oslo were invited to an ultrasonographic screening of the abdominal aorta. Candidates received a one-time invitation by mail, including a questionnaire on possible risk factors and comorbidities. Abdominal aortic outer-to-outer diameter and ankle-brachial index were measured by the screening team. Participants were allocated into three groups: non-, sub- and aneurysmal aorta. Written information on recommended follow-up regime was given to participants with an aortic diameter ≥25 mm. Univariate and multivariate analyses of potential risk factors were performed, in addition to descriptive analyses and significance testing.

Results

In total, 19,328 were invited, 13,215 men were screened, of which 12,822 accepted inclusion in the study. Aortic diameter was registered for 12,810 participants and 330 men had aortic diameter ≥30 mm, giving a prevalence of AAA of 2.6% (95% confidence interval (CI) 2.31-2.86). We identified 4 independent risk factors for AAA: smoking (OR = 3.64, 95% CI 2.90-4.58), hypertension (OR = 1.87, 95% CI 1.49-2.35), BMI >30 (OR = 1.02, 95% CI 1.00-1.03), and diabetes mellitus (OR = 0.52, 95% CI 0.35-0.79), the latter showing an inverse association with AAA growth. A subgroup of 862 men with aortic diameters 25-29 mm had a significantly higher prevalence of BMI >25, smoking and family history of AAA, compared to participants with aortic diameter <25 mm.

Conclusion

Among the participants in this study, the prevalence of abdominal aortic aneurysms was 2.6%. Participants with AAA more frequently reported cardiovascular risk factors, and less frequently diabetes mellitus.

Sex Hormones in Men with Abdominal Aortic Aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) primarily affects elderly men. The impact of sex on aneurysm development has been associated with an effect of sex hormones, through mechanisms that are not fully understood. This study aimed to examine the association between levels of sex hormones and the occurrence of AAA in elderly men.

METHODS

A prospective case-control study was conducted including 452, 65-year old men participating in screening for AAA, 2013-2019; 230 men with AAA and 222 men with an aortic diameter<30mm (controls). Questionnaires and blood samples were collected and stored consecutively. Serum levels of total testosterone, estradiol, progesterone, luteinizing hormone and sex hormone binding globulin were analyzed by electrochemiluminescent immunoassays. Multivariable logistic regression analysis was used to assess the association of sex hormones with AAA.

RESULTS

The median aneurysm diameter was 33mm. Men with AAA had higher estradiol and progesterone levels than controls (93pmol/L vs. 84pmol/L, p=.003 and 0.41nmol/L vs. 0.17nmol/L, p<.001). Testosterone levels were lower in men with AAA than in controls (13nmol/L vs. 14nmol/L, p=.026). AAA was associated with detectable levels of progesterone(OR 6.69, 95%CI 3.86-11.47), smoking(OR 5.26, 95%CI 3.12-8.85), coronary heart disease(OR 4.06, 95%CI 1.92-8.58) and body mass index>25(OR 2.26, 95%CI 1.34-3.82).

CONCLUSION

The observed higher levels of estradiol and progesterone in men with AAA, suggest an impact of sex hormones on aneurysm development. The association between progesterone levels and aortic diameter, stress the importance of focusing on the potential effect of this unconsidered female sex hormone on aneurysm formation.

Usefulness of Screening for Abdominal Aortic Aneurysm During Transthoracic Echocardiography in Women ≥50 Years of Age

Usefulness of screening for abdominal aortic aneurysm (AAA) during transthoracic echocardiography (TTE) in women is uncertain. The aim of the present study was to clarify the clinical usefulness of screening for AAA during TTE and to identify important TTE indices associated with AAA in women in a routine clinical setting. We prospectively studied 1,495 women (≥50 years) referred for TTE. AAA was defined as ≥30 mm in size. The additional screening time for AAA was <1 minute. The abdominal aorta was visualized in 95.1 % (1,422 of 1,495) using the same TTE probe. AAA was identified in 1.9% (27 of 1422). The aortic root size was larger in patients with AAA than those without (33.3 ± 3.2 vs 30.5 ± 3.4 mm, p < 0.001). The aortic root size had a correlation with abdominal aortic size (r = 0.22, p < 0.001). The aortic root size of ≥30.3 mm was predictive of AAA (area under the curve = 0.74, p < 0.001) and all patients with AAA had the aortic root size of ≥28.0 mm. Multiple logistic regression analysis revealed that the aortic root size (Odds ratio 1.17, p = 0.007) was a most independent TTE index of AAA. In conclusion, the visibility of the abdominal aorta using TTE probe was excellent. When the aortic root size is ≥28.0 mm during TTE in women ≥50 years of age, screening for AAA should be carried out.

Perivascular Adipose Tissue-Derived PDGF-D Contributes to Aortic Aneurysm Formation During Obesity

Obesity increases the risk of vascular diseases, including aortic aneurysm (AA). Perivascular adipose tissue (PVAT) surrounding arteries are altered during obesity. However, the underlying mechanism of adipose tissue, especially PVAT, in the pathogenesis of AA is still unclear. Here we showed that angiotensin II (AngII) infusion increases the incidence of AA in leptin-deficient obese mice (ob/ob) and high-fat diet-induced obese mice with adventitial inflammation. Furthermore, transcriptome analysis revealed that platelet-derived growth factor-D (PDGF-D) was highly expressed in the PVAT of ob/ob mice. Therefore, we hypothesized that PDGF-D mediates adventitial inflammation, which provides a direct link between PVAT dysfunction and AA formation in AngII-infused obese mice. We found that PDGF-D promotes the proliferation, migration, and inflammatory factors expression in cultured adventitial fibroblasts. In addition, the inhibition of PDGF-D function significantly reduced the incidence of AA in AngII-infused obese mice. More importantly, adipocyte-specific PDGF-D transgenic mice are more susceptible to AA formation after AngII infusion accompanied by exaggerated adventitial inflammatory and fibrotic responses. Collectively, our findings reveal a notable role of PDGF-D in the AA formation during obesity, and modulation of this cytokine might be an exploitable treatment strategy for the condition.

Increased Risk of Peripheral Arterial Disease in Patients With Abdominal Aortic Aneurysm: A Retrospective Cohort Study (Version 5)

Studies evaluating the risk of peripheral arterial disease (PAD) in patients with abdominal aortic aneurysm (AAA) are limited. We used insurance claims data of Taiwan to establish a cohort of 6590 patients with AAA newly diagnosed from 2000 to 2008 and 6590 controls without AAA matched by propensity score. The subsequent incidence density rates of PAD were estimated in both cohorts by the end of 2011, and the AAA cohort to the non-AAA cohort hazard ratios (HRs) of PAD were calculated using Cox proportional hazards models. The incidence density of PAD in the AAA cohort was 3.7-fold greater than that in the non-AAA cohort (14.1 vs 3.66 per 1000 person-years) with an adjusted HR of 3.56 (95% confidence interval [CI] = 2.89-4.39). For those without comorbidities, PAD in the AAA cohort was 7.4-fold greater than that in the non-AAA cohort (12.0 vs 1.61 per 1000 person-years) with an adjusted HR of 6.70 (95% CI = 4.43-10.1). The incidence of PAD in patients with ruptured AAA was lower than that in patients without rupture (6.95 vs 15.0 per 1000 person-years). This study demonstrates that patients with AAA are at increased risk of developing PAD.

Abdominal aortic aneurysm: Sex differences

OBJECTIVE

Abdominal aortic aneurysm (AAA) predominantly affects an elderly male population. Even so, AAA appears more detrimental in women, who experience a higher risk of aneurysm rupture and a worse outcome after surgery than men. Why women are privileged from yet are worse off once affected has been attributed to an effect of sex hormones. This review summarizes the knowledge of sex differences in AAA and addresses the changes in the aneurysm wall from a gender perspective.

METHOD

Standard reporting guidelines set by the PRISMA Group were followed to identify studies examining AAA from a gender perspective. Relevant reports were identified using two electronic databases: PubMed and Web of Science. The systematic search was performed in two stages: firstly, using the terms AAA and gender/sex/women; and secondly, adding the terms "elastin", "collagen" and "vascular smooth muscle cells", in order to filter the search for studies relevant to our focus on the aneurysm wall.

CONCLUSION

Current studies support the theory that sex has an effect on aneurysm formation, yet are inconclusive about whether or not aneurysm formation is dependent on female/male sex hormones or a lack thereof. The studies in women are scarce and out of those most reports primarily address other end-points, which limit their ability to illuminate an effect of sex on aneurysm formation. The complexity of the human menstrual cycle and menopausal transition are difficult to mimic in animal models, which limit their applicability to AAA formation in humans.

Predictors Associated With Increased Prevalence of Abdominal Aortic Aneurysm in Chinese Patients with Atherosclerotic Risk Factors

OBJECTIVE/BACKGROUND

Epidemiological screening studies have demonstrated that the prevalence of abdominal aortic aneurysm (AAA) of Asian origin appears to be low and so increases uncertainty about the cost effectiveness of screening for AAAs in Chinese people. Some studies have demonstrated a higher prevalence of AAA in patients with atherosclerotic risk factors. The purpose of the study was to determine the prevalence of AAA and to explore the high risk group of AAA in Chinese patients with atherosclerotic risk factors.

METHODS

From November 2014 to July 2015, a prospective observational study was conducted in Guangdong General Hospital. In total, 1582 consecutive patients with atherosclerotic risk factors and undergoing coronary angiography for suspected or known coronary artery disease were enrolled to be screened for AAA by abdominal aortic ultrasound. Because of inadequate ultrasound image quality, the analysis was based on the 1541 (97.4%) patients whose abdominal aortic ultrasound images were adequate.

RESULTS

The prevalence of AAA was 1.6% in the whole study population and 2.9% in male patients aged over 65 years. In multivariate analysis, age ≥ 65 years (p = .029), smoking (p = .037), hypertension (p = .026), and aortic root diameter > 30 mm (p = .003) were independent predictors of AAA. The prevalence of AAA was 0% (0/153) in patients without any independent predictor, 0.6% (3/502) in patients with one predictor, 1.0% (6/597) in patients with two predictors, 4.8% (12/249) in patients with three predictors, and up to 10% (4/40) in patients with four predictors (p<.001; p value for trend < .001).

CONCLUSION

Age ≥ 65 years, smoking, hypertension, and aortic root diameter > 30 mm emerged as independent predictors of AAA in Chinese patients. Stepwise increases in the prevalence of AAA were found to depend on the number of independent predictors. Ultrasound screening for AAA could be considered in these high risk patients, especially those with three or four predictors.