The case for expanding abdominal aortic aneurysm screening

Effect of EVAR on International Ruptured AAA Mortality-Sex and Geographic Disparities

Background: We sought to investigate the differential impact of EVAR (endovascular aneurysm repair) vis-à-vis OSR (open surgical repair) on ruptured AAA (abdominal aortic aneurysm) mortality by sex and geographically. Methods: We performed a retrospective study of administrative data on EVAR from state statistical agencies, vascular registries, and academic publications, as well as ruptured AAA mortality rates from the World Health Organization for 14 14 states across Australasia, East Asia, Europe, and North America. Results: Between 2011-2016, the proportion of treatment of ruptured AAAs by EVAR increased from 26.1 to 43.8 percent among females, and from 25.7 to 41.2 percent among males, and age-adjusted ruptured AAA mortality rates fell from 12.62 to 9.50 per million among females, and from 34.14 to 26.54 per million among males. The association of EVAR with reduced mortality was more than three times larger (2.2 vis-à-vis 0.6 percent of prevalence per 10 percentage point increase in EVAR) among females than males. The association of EVAR with reduced mortality was substantially larger (1.7 vis-à-vis 1.1 percent of prevalence per 10 percentage point increase in EVAR) among East Asian states than European+ states. Conclusions: The increasing adoption of EVAR coincided with a decrease in ruptured AAA mortality. The relationship between EVAR and mortality was more pronounced among females than males, and in East Asian than European+ states. Sex and ethnic heterogeneity should be further investigated.

Metabolic syndrome and the risk of abdominal aortic aneurysm: A nationwide cohort study

BACKGROUND AND AIMS

The association between metabolic syndrome (MetS) and abdominal aortic aneurysm (AAA) remains unclear. We investigated the potential association between AAA and MetS and its components in a large population-based cohort.

METHODS

We used the Korean National Health Insurance Service database including 4,162,640 participants aged ≥50 years who received a routine health examination in 2009. Cox proportional hazards models were used to analyze the association between MetS and its components (elevated waist circumference, blood pressure, glucose, triglycerides, and reduced high-density lipoprotein cholesterol [HDL-C]) with AAA incidence, with adjustment for confounders.

RESULTS

During a median 9.4 years of follow-up, 18,160 participants developed incident AAA. MetS was associated with an increased risk of AAA compared to the non-MetS group (adjusted hazard ratio [aHR], 1.38; 95% confidence interval [CI], 1.34-1.43). Among the individual components, elevated waist circumference, blood pressure, triglycerides, and reduced HDL-C were associated with increased AAA risk, while elevated glucose alone was associated with reduced AAA risk (aHR, 0.85; 95% CI, 0.82-0.87). AAA risk also increased linearly with the increasing number of MetS components, with the highest risk found in the presence of all 5 components (aHR, 1.98, 95% CI, 1.83-2.15).

CONCLUSIONS

MetS and its individual components, with the exclusion of elevated glucose, were associated with higher risk of AAA. Further studies are warranted to elucidate the association between MetS and AAA.

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.

Infrarenal Abdominal Aortic Aneurysm

Abdominal aortic aneurysms are found in up to 6% of men and 1.7% of women over the age of 65 years and are usually asymptomatic. The natural history of aortic aneurysms is continued dilation leading to rupture, which is associated with an overall 80% mortality. Of the patients with ruptured aneurysms that undergo intervention, half will not survive their hospitalization. Reduction in aneurysm mortality is therefore achieved by prophylactic repair during the asymptomatic period. On a population-based level, this is supported by abdominal aortic aneurysm screening programs. Approximately 60% of abdominal aortic aneurysms are confined to the infrarenal portion of the aorta and are amenable to repair with off-the-shelf endovascular devices. Endovascular techniques have now replaced open surgery as the primary modality for aneurysm repair.

Sex Differences in Outcomes Following Ruptured Abdominal Aortic Aneurysm Repair

IMPORTANCE

Sex differences in aortic surgery outcomes are commonly reported. However, data on ruptured abdominal aortic aneurysm (rAAA) repair outcomes in women vs men are limited.

OBJECTIVE

To assess differences in perioperative and long-term mortality following rAAA repair in women vs men.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter, retrospective cohort study was conducted using the Vascular Quality Initiative database, which prospectively captures information on patients who undergo vascular surgery across 796 academic and community hospitals in North America. All patients who underwent endovascular or open rAAA repair between January 1, 2003, and December 31, 2019, were included. Outcomes were assessed up to January 1, 2020.

EXPOSURES

Patient sex.

MAIN OUTCOMES AND MEASURES

Demographic, clinical, and procedural characteristics were recorded, and differences between women vs men were assessed using independent t test and χ2 test. The primary outcomes were in-hospital and 8-year mortality. Associations between sex and outcomes were analyzed using univariable and multivariable logistic regression and Cox proportional hazards regression analysis.

RESULTS

A total of 1160 (21.9%) women and 4148 (78.1%) men underwent rAAA repair during the study period. There was a similar proportion of endovascular repairs in women and men (654 [56.4%] vs 2386 [57.5%]). Women were older (mean [SD] age, 75.8 [9.3] vs 71.7 [9.6] years), more likely to have chronic kidney disease (718 [61.9%] vs 2184 [52.7%]), and presented with ruptured aneurysms of smaller diameters (mean [SD] 68 [18.2] vs 78 [30.2] mm). In-hospital mortality was higher in women (34.4% vs 26.6%; odds ratio, 1.44; 95% CI, 1.25-1.66), which persisted after adjusting for demographic, clinical, and procedural characteristics (adjusted odds ratio, 1.36; 95% CI, 1.12-1.66; P = .002). Eight-year survival was lower in women (36.7% vs 49.5%; hazard ratio, 1.25; 95% CI, 1.04-1.50; P = .02), which persisted when stratified by endovascular and open repair. This survival difference existed in both the US and Canada. Variables associated with long-term mortality in women included older age and chronic kidney disease.

CONCLUSIONS AND RELEVANCE

Women who underwent rAAA repair had higher perioperative and 8-year mortality rates following both endovascular and open repair compared with men. Older age and higher rates of chronic kidney disease in women were associated with higher mortality rates. These findings suggest that future studies should assess the reasons for these disparities and whether opportunities exist to improve AAA care for women.

Overview of screening eligibility in patients undergoing ruptured AAA repair from 2003 to 2019 in the Vascular Quality Initiative

OBJECTIVE

Although efforts such as the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act have improved access to abdominal aortic aneurysm (AAA) screening, certain high-risk populations are currently excluded from the guidelines yet may benefit from screening. We therefore examined all patients who underwent repair of ruptured AAA (rAAA) to characterize those who are ineligible for screening under current guidelines and evaluate the potential impact of these restrictions on their disease.

METHODS

We identified patients undergoing rAAA repair in the Vascular Quality Initiative (VQI) database between 2003 and 2019. These patients were stratified by AAA screening eligibility according to the Centers for Medicare and Medicaid reimbursement guidelines. We then described baseline characteristics to identify high-risk features of these cohorts. Groups with disproportionate representation in the screening-ineligible cohort were identified as potential targets of screening expansion. Trends over time in screening eligibility and the proportion of AAA repairs performed for rAAA were also analyzed.

RESULTS

A total of 5340 patients underwent rAAA repair. The majority (66%) were screening-ineligible. When characterizing the screening-ineligible group by sex and risk factors (smoking history or family history of AAA), the largest contributors to screening ineligibility were males less than 65 years of age with a smoking history or family history of AAA (25%), males greater than 75 years of age with a smoking history (25%), and females older than 65 years of age with a smoking history (19%). In comparison with rAAAs prior to implementation of the SAAAVE act, the proportion of AAA repair performed for rupture among males undergoing AAA repair in the VQI decreased from 12% to 8% (P < .001), whereas in females, there was no change (P = .990). There was no statically significant difference in screening eligibility for either males (P = .762) or females (P = .335).

CONCLUSIONS

Most patients who underwent rAAA repair were ineligible for initial AAA screening or aged out of the screening window. Furthermore, rAAA rates and screening ineligibility have not improved as much as expected since the passage of the SAAAVE Act. Our data suggest that three high-risk populations may benefit from expansion of AAA screening guidelines: males with a smoking history or family history of AAA between ages 55 and 64 years, female smokers older than 65 years, and male smokers older than 75 years who are otherwise in good health. Increased efforts to screen these high-risk populations may increase elective AAA repair and minimize the morbidity and mortality associated with rAAAs.

Costs of abdominal aortic aneurysm care at a regional Veterans Affairs medical center with the implementation of an abdominal aortic aneurysm screening program

BACKGROUND

Abdominal aortic aneurysm (AAA) screening has demonstrated to be cost-effective in reducing AAA-related morbidity and all-cause mortality. However, the downstream care costs of an implemented AAA screening in clinical practice have not been reported. The purpose of this study is to determine direct regional Department of Veterans Affairs (VA) costs in implementing and sustaining an AAA screening program over a 10-year period.

METHODS

A cost data analysis (adjusted to 2021 U.S. dollars) of an AAA screening program was conducted from 2007 to 2016, where 19,649 veteran patients aged 65-75 with a smoking history were screened at a regional VA medical center. A decision support system tracked direct and indirect encounter costs from Medicare billing codes associated with AAA care. Costs from a patient's initial screening, follow-up imaging, to AAA repair or at the end of the analysis period, March 31, 2021, were recorded. Costs for AAA repairs outside the VA system were also tracked.

RESULTS

A total of 1,183 patients screened were identified with an AAA ≥3.0 cm without history of repair. Estimated screening costs were $2.8 million or $280,000 annually ($143/screening) in the care of 19,649 screened patients. There were 221 patients who required repair (143 repairs in VA, 78 repairs outside VA). The average cost of elective endovascular repair was $43,021 and that of open repair was $49,871. The total costs for all elective repairs were $9,692,591. Screening, implementation, maintenance, and surgical repair cost involved in the management of patients with AAA disease was $13.7 million, with $10,686 per life-year lived after repair (5.8 ± 3.5 mean life-years) and $490 per life-year lived after screening (6.9 ± 3.5 mean life-years) for all patients screened. There were 13 deaths of unknown causes and one patient with a ruptured AAA that required emergency repair at a cost of $124,392.

CONCLUSIONS

Despite known limitations, the implementation of an AAA ultrasound screening program is feasible, cost-effective, and a worthwhile endeavor.

Prediction model of isolated iliac and abdominal aneurysms

OBJECTIVES

We analyse the cardiovascular risk factors in patients undergoing screening for Isolated Iliac Aneurysm (IIA) and Abdominal Aortic Aneurysm (AAA) and propose a logistic regression model to indicate patients at risk of IIA and/or AAA.

METHODS

A screening programme was carried out to identify the presence of aneurysm based on Duplex scan examination. Cardiovascular risk factors information was collected from each subject. A descriptive analysis for the incidence of IIA and AAA stratified by age and sex was carried out to evaluate factors incidence. A logistic regression model was developed to predict the probability of developing an aneurysm based on the observed risk factor levels. A threshold probability of aneurysm risk for a datum patient was also identified to effectively direct screening protocols to patients most at risk.

RESULTS

A cohort of 10 842 patients was evaluated: 1.52% affected by IIA, 2.69% by AAA and 3.90% by at least one. Risk factors analysis showed that: IIA was correlated with cardiological status, diabetes, cardiovascular disease family history, and dyslipidaemia; AAA was correlated with cardiological status, body mass index, hypertension, and dyslipidaemia; diabetes and dyslipidaemia were the most relevant factors with at least one aneurysm. The prediction tool based on the logistic regression and the threshold probability predict the presence of IIA and AAA in 69.7% and 83.8% of cases, under k-fold cross-validation.

CONCLUSIONS

The proposed regression model can represent a valid aid to predict IIA and AAA presence and to select patients to be screened.