Correcting for Body Surface Area Identifies the True Prevalence of Abdominal Aortic Aneurysm in Screened Women

Proprotein convertase subtilisin/kexin type 9 as a drug target for abdominal aortic aneurysm

PURPOSE OF REVIEW

There are no current drug therapies to limit abdominal aortic aneurysm (AAA) growth. This review summarizes evidence suggesting that inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9) may be a drug target to limit AAA growth.

RECENT FINDINGS

Mendelian randomization studies suggest that raised LDL and non-HDL-cholesterol are causal in AAA formation. PCSK9 was reported to be upregulated in human AAA samples compared to aortic samples from organ donors. PCSK9 gain of function viral vectors promoted aortic expansion in C57BL/6 mice infused with angiotensin II. The effect of altering PCSK9 expression in the aortic perfusion elastase model was reported to be inconsistent. Mutations in the gene encoding PCSK9, which increase serum cholesterol, were associated with increased risk of human AAA. Patients with AAA also have a high risk of cardiovascular death, myocardial infarction and stroke. Recent research suggests that PCSK9 inhibition would substantially reduce the risk of these events.

SUMMARY

Past research suggests that drugs that inhibit PCSK9 have potential as a novel therapy for AAA to both limit aneurysm growth and reduce risk of cardiovascular events. A large multinational randomized controlled trial is needed to test if PCSK9 inhibition limits AAA growth and cardiovascular events.

How to improve epidemiological trustworthiness concerning abdominal aortic aneurysms

BACKGROUND

Research on degenerative abdominal aortic aneurysms (AAA) is hampered by complex pathophysiology, sub-optimal pre-clinical models, and lack of effective medical therapies. In addition, trustworthiness of existing epidemiological data is impaired by elements of ambiguity, inaccuracy, and inconsistency. Our aim is to foster debate concerning the trustworthiness of AAA epidemiological data and to discuss potential solutions.

METHODS

We searched the literature from the last five decades for relevant epidemiological data concerning AAA development, rupture, and repair. We then discussed the main issues burdening existing AAA epidemiological figures and proposed suggestions potentially beneficial to AAA diagnosis, prognostication, and management.

RESULTS

Recent data suggest a heterogeneous scenario concerning AAA epidemiology with rates markedly varying by country and study cohorts. Overall, AAA prevalence seems to be decreasing worldwide while mortality is apparently increasing regardless of recent improvements in aortic-repair techniques. Prevalence and mortality are decreasing in high-income countries, whereas low-income countries show an increase in both. However, several pieces of information are missing or outdated, thus systematic renewal is necessary. Current AAA definition and surgical criteria do not consider inter-individual variability of baseline aortic size, further decreasing their reliability.

CONCLUSIONS

Switching from flat aortic-size thresholds to relative aortic indices would improve epidemiological trustworthiness regarding AAAs. Aortometry standardization focusing on simplicity, univocity, and accuracy is crucial. A patient-tailored approach integrating clinical data, multi-adjusted indices, and imaging parameters is desirable. Several novel imaging modalities boast promising profiles for investigating the aortic wall. New contrast agents, computational analyses, and artificial intelligence-powered software could provide further improvements.

Body surface area is positively associated with ankle-brachial index

BACKGROUND

Ankle-brachial index (ABI) measurement is a widely used diagnostic test for lower extremity artery disease. Previously, a larger body surface area (BSA) has been associated with lower blood pressure and lower 2-h post-load glucose concentrations in the oral glucose tolerance test. Our aim was to evaluate whether BSA has an impact on ABI and the prevalence of lower ABI values.

METHODS

ABI measurements were performed on 972 subjects aged 45 to 70 years at high cardiovascular disease (CVD) risk. Subjects with previously diagnosed kidney disease, CVD, and diabetes were excluded. Their BSA was calculated by the Mosteller formula. Study subjects were divided into five BSA levels corresponding to 12.5th, 25th, 25th, 25th, and 12.5th percentiles of the total distribution. Effect modification by BSA in ABI between sexes was derived from a four-knot restricted cubic splines regression model.

RESULTS

After adjustments for age, sex, pulse pressure, glucose regulation, waist circumference, alcohol intake, smoking status, leisure-time physical activity and medication, BSA level had a positive linear relationship with ABI (p for linearity <0.001). When BSA was less than 2.0 m2, there was no difference between the sexes, but when BSA was higher than 2.0 m2, men had higher ABI.

CONCLUSION

BSA shows a positive linear relationship with ABI in CVD risk subjects without manifested CVD. The difference in ABI between men and women is modified by BSA and is appreciable when BSA is larger than 2.0 m2.

Aortic Size Index Versus Aortic Diameter in the Prediction of Rupture in Women With Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAAs) pose significant challenges in clinical management, particularly in female patients, whose unique anatomical and physiological characteristics influence rupture risk. While aortic diameter (AD) has traditionally been the primary metric for predicting rupture, its limitations, especially in women, have spurred exploration into alternative measures such as the aortic size index (ASI). This review examines the anatomy and physiology of AAAs in women, gender-specific challenges in diagnosis and management, and the comparative effectiveness of ASI versus AD in predicting rupture risk. ASI, calculated as AD divided by body surface area (BSA), offers a more nuanced assessment by adjusting for individual body size differences, potentially mitigating gender disparities in rupture rates. Comparative analyses indicate ASI's superiority in predicting adverse aortic events, particularly in women, thereby advocating for its integration into clinical practice to improve patient outcomes. Additionally, emerging techniques such as 3D volumetric measurements and biomechanical assessments show promise in enhancing rupture risk prediction, heralding a shift toward more personalized and effective management strategies for AAA patients.

Association of women-specific size threshold and mortality in elective abdominal aortic aneurysm repair

BACKGROUND

It is unclear whether women derive mortality benefit from early repair of abdominal aortic aneurysms (AAA). The aim of this study was to compare short- and mid-term mortality for women treated at small versus large diameters.

METHOD

Women receiving elective repair of AAA at small (49-54 mm) and large (≥55 mm) diameters from 2008 to 2022 were extracted from the Swedish National Registry for Vascular Surgery (n = 1642 women). The effect of diameter on 90-day, 1- and 3-year mortality was studied in logistic regression and propensity score models. Age, co-morbidities, smoking and repair modality were considered as confounders. Men (n = 9047) were analysed in parallel.

RESULTS

Some 1642 women were analysed, of whom 34% underwent repair at small diameters (versus 52% of men). Women with small (versus large) AAAs were younger (73 versus 75 years, P < 0.001), and 63% of women in both size groups had endovascular repairs (P = 0.120). Mortality was 3.5% (90 days), 7.1% (1 year) and 15.8% (3 years), with no differences between the size strata. There was no consistent association between AAA size and mortality in multivariable models. Sex differences in mortality were almost entirely due to mortality in younger-than-average women versus men (3-year mortality: small AAAs 11.1% versus 7.3%, P < 0.030, or large 14.4% versus 10.7%, P < 0.038).

CONCLUSION

Mortality in women is high and unaffected by AAA size at repair. The optimal threshold for women remains undefined. The higher rupture risk in women should not automatically translate into a lower, women-specific threshold.

Women with large intact abdominal aortic aneurysms remain untreated

OBJECTIVE

A lower elective repair rate among women with abdominal aortic aneurysms (AAAs) has been a consistent finding. Reasons behind this gender gap have not been thoroughly outlined.

METHODS

This was a retrospective multicenter cohort study (ClinicalTrials.gov: NCT05346289) at three European vascular centers in Sweden, Austria and Norway. Patients in surveillance with AAAs were consecutively identified starting from January 1, 2014, until reaching a total sample size of 200 women and 200 men. All individuals were followed for 7 years through medical records. Final treatment distributions and the proportion of "truly untreated" (surgically untreated despite reaching guideline-directed thresholds: 50 mm for women and 55 mm for men) were determined. In a complementary analysis, a universal 55-mm threshold was used. Gender-specific primary reasons behind untreated statuses were clarified. Eligibility for endovascular repair among the truly untreated was assessed in a structured computed tomography analysis.

RESULTS

Women and men had similar median diameters at inclusion (46 mm; P = .54) and at treatment decisions (55 mm; P = .36). After 7 years, the repair rate was lower among women (47% vs 57%). More women were truly untreated (26% vs 8%; P < .001) despite similar mean ages as for male counterparts (79.3 years; P = .16). With the 55-mm threshold, 16% women still classified as truly untreated. Similar reasons for nonintervention were captured for women and men (50% due to comorbidities alone, 36% morphology and comorbidity). The endovascular repair imaging analysis revealed no gender differences. Among truly untreated women, ruptures were common (18%), and mortality was high (86%).

CONCLUSIONS

Surgical AAA management differed between women and men. Women could be underserved in terms of elective repairs: one in every four women was untreated with over-the-threshold AAAs. The lack of obvious gender differences in eligibility analyses could imply unmeasured discrepancies (eg, in disease extent or patient frailty).

Renal hyperfiltration revisited-Role of the individual body surface area on mortality

BACKGROUND

Higher than normal estimated glomerular filtration rate (eGFR), i.e. renal hyperfiltration (RHF), has been associated with mortality.

METHODS

A population-based screening program in Finland identified 1747 apparently healthy middle-aged cardiovascular risk subjects in 2005-2007. GFR was estimated with the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation indexed for 1.73 m2 and for the actual body surface area (BSA) of the subjects. This individually corrected eGFR was calculated as eGFR (ml/min/BSA m2) = eGFR (ml/min/1.73 m2) x (BSA/1.73). BSA was calculated by the Mosteller formula. RHF was defined as eGFR of more than 1.96 SD above the mean eGFR of healthy individuals. All-cause mortality was obtained from the national registry.

RESULTS

The higher the eGFR, the greater was the discrepancy between the two GFR estimating equations. During the 14 years of follow-up, 230 subjects died. There were no differences in mortality rates between the categories of individually corrected eGFR (p = 0.86) when adjusted for age, sex, body mass index, systolic BP, total cholesterol, new diabetes, current smoking, and alcohol use. The highest eGFR category was associated with increased standardized mortality rate (SMR) when CKD-EPI formula indexed for 1.73 m2 was used, but SMR was at the population level when individually corrected eGFR was applied.

CONCLUSIONS

Higher than normal eGFR calculated by the creatinine-based CKD-EPI equation is associated with all-cause mortality when indexed to 1.73 m2, but not when indexed to actual BSA of a person. This challenges the current perception of the harmfulness of RHF in apparently healthy individuals.

Pathogenesis and management of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) causes ∼170 000 deaths annually worldwide. Most guidelines recommend asymptomatic small AAAs (30 to <50 mm in women; 30 to <55 mm in men) are monitored by imaging and large asymptomatic, symptomatic, and ruptured AAAs are considered for surgical repair. Advances in AAA repair techniques have occurred, but a remaining priority is therapies to limit AAA growth and rupture. This review outlines research on AAA pathogenesis and therapies to limit AAA growth. Genome-wide association studies have identified novel drug targets, e.g. interleukin-6 blockade. Mendelian randomization analyses suggest that treatments to reduce low-density lipoprotein cholesterol such as proprotein convertase subtilisin/kexin type 9 inhibitors and smoking reduction or cessation are also treatment targets. Thirteen placebo-controlled randomized trials have tested whether a range of antibiotics, blood pressure-lowering drugs, a mast cell stabilizer, an anti-platelet drug, or fenofibrate slow AAA growth. None of these trials have shown convincing evidence of drug efficacy and have been limited by small sample sizes, limited drug adherence, poor participant retention, and over-optimistic AAA growth reduction targets. Data from some large observational cohorts suggest that blood pressure reduction, particularly by angiotensin-converting enzyme inhibitors, could limit aneurysm rupture, but this has not been evaluated in randomized trials. Some observational studies suggest metformin may limit AAA growth, and this is currently being tested in randomized trials. In conclusion, no drug therapy has been shown to convincingly limit AAA growth in randomized controlled trials. Further large prospective studies on other targets are needed.

Gender-specific Predicted Normal Aortic Size and Its Consequences of the Population-Based Prevalence of Abdominal Aortic Aneurysms

BACKGROUND

To investigate if a relative-size-index of the abdominal aortic diameter influences the prevalence estimates of abdominal aortic dilatations compared to absolute diameters.

METHODS

Cross-sectional study. Participants from the Viborg Vascular Screening Trial, Viborg Women Cohort, and the Viborg Screening Program. Through multivariate linear regression analyses, 2 gender-specific prediction-equations were developed based upon body-surface area and age. The definitions of absolute and relative size of aortic ectasies were 25-29 mm and 1.25-1.49× individual-predicted size (IPS), abdominal aortic aneurysm (AAA) 30 mm and 1.5× IPS, and large repair-recommendable AAA ≥55 mm or ≥ 2.75× IPS, respectively.

RESULTS

Nineteen thousand two hundred and sixty nine males (69.6 years) and 2,426 females (67.1 years) attended the population- and ultrasound-based screening studies for AAA. The mean peak systolic abdominal anterior-posterior inner to inner diameter was 19.1 mm (±5.3 mm) and 16.6 mm (±2.8 mm) (P < 0.001) in males and females, respectively. Body surface area showed the strongest correlation with aortic diameters in both males (r = 0.19, P < 0.001) and females (r = 0.17, P < 0.001). Age correlated significantly with size, but only in males (r = 0.03, P < 0.001). The prevalence in men of absolute size-defined and relative size index-defined screening-detected aortic ectasies, AAAs and repair-recommendable AAAs were: 5.9% and 9.5% (P < 0.001), 3.3% and 4.2% (P < 0.001) and 9.9% and 15.2% (P = 0.004), respectively. Prevalence in females of absolute-size-defined and relative-size-index-defined screening-detected aortic ectasies, AAAs and repair-recommendable AAAs were 1.2% and 5.8% (P < 0.001), 0.5% and 1.3% (P = 0.003) and 0.0% and 23.1% (P = 0.553), respectively.

CONCLUSIONS

Despite statistical differences, ultrasound-based absolute diameters to detect AAA seem acceptable in men. In females, poor agreements were noticed concerning all 3 categories of aneurysms, indicating that the current absolute diagnostic cut-points do not reflect female anatomy.

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.

Abdominal aortic aneurysm growth rates are not correlated to body surface area in screened men

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) in 65-year-old males reduces aneurysm related mortality. Infrarenal aortic diameter (IAD) has been shown to correlate to body surface area (BSA) which could influence diagnostic criteria for AAA. This study investigates whether AAA growth rates are also dependent on BSA, as that might have potential effects on surveillance of small AAAs.

METHODS

We conducted a retrospective, single center cohort study of 301 men with screening detected AAA between 2010-2017 with surveillance to 2021. AAA growth rates were analyzed in relation to the subject's BSA, smoking habits, and diabetic disease using a linear mixed-effects model. All men were offered smoking cessation program, optimized medical treatment, and advice on physical activity.

RESULTS

The screening program included 28,784 men. Of the 22,819 (79%) attending the examinations, 374 men (1.6%) were found to have an AAA out of which 301 men had undergone two or more examinations during surveillance and were included with a median follow-up of 1846 days (IQR: 1 399). Mean unadjusted AAA growth rate was 1.60 mm/year (95% CI: 1.41-1.80). Diabetes mellitus had a statistically significant negative impact, smoking had a statistically significant positive impact on AAA growth rates whereas no correlation between AAA growth rate and BSA could be found.

CONCLUSIONS

Body surface area could not be found to have a statistically significant correlation to AAA growth rates. The impact of smoking and diabetes on AAA growth rates remains similar to previously reported.

Prevalence and Risk Factors of Abdominal Aortic Aneurysms Detected with Ultrasound in Korea and Belgium

The objective was to investigate the prevalence of abdominal aortic aneurysms (AAAs) and the diameters of the aorta and common iliac arteries (CIAs) in a Korean cohort and secondly to analyze the differences in aortic diameter by comparison with a European cohort. The Korean cohort included participants ≥ 50 years who consented to AAA screening and data were analysed retrospectively. Aortic and common iliac diameters were measured using the outer-to-outer diameter method and prevalence rates were calculated. Common risk factors such as smoking, body mass index, pulmonary disease, hypertension, diabetes, hyperlipidaemia, ischaemic heart disease, and cerebrovascular disease were reported in association with AAA occurrence and AAA development. The aortic diameters were then compared with those in a Belgian cohort of 2487 participants identified in the Liège AAA Screening Program. An aortic size index (ASI) was also calculated to account for the potential size differences in the Belgian and Korean populations. A total of 3124 Korean participants were examined using ultrasound. The prevalence of AAAs in this cohort was 0.7%. The combined prevalence of subaneurysmal dilatation and AAA was 1.5%. The prevalence in male smokers older than 65 years was 2.7% (19/715). The mean infrarenal aortic diameter was 17.3 ± 3.1 mm in men and 15.7 ± 2.7 mm in women; the corresponding values in Belgian participants were 19.4 ± 3.0 mm in men and 17.9 ± 2.4 mm in women. The median aortic size index was 0.99 (interquartile range 0.88-1.12). The mean infrarenal aortic diameter was significantly smaller in the Korean cohort than in the Belgian cohort. Considering the observed prevalence of AAAs in different age groups, the age groups which would contribute to most cases was male persons above 66 years in both cohorts.

Endovascular Repair of Complex Aortic Aneurysms

Fenestrated-branched endovascular aortic repair (FB-EVAR) has gained widespread acceptance in patients with complex aortic aneurysms. It has evolved from an alternative to treat elderly and higher risk patients to the first line of treatment in most patients with suitable anatomy, independent of the clinical risk. Currently, these devices are available off-the-shelf (ready to use) and tailored to the patient anatomy with the options of fenestrated, branched and mixed fenestrated, and branched designs. Reports from single and multicenter experiences and systematic reviews have shown lower mortality and morbidity for FB-EVAR compared with historical results of open surgical repair. The main advantages are noted on mortality, respiratory complications, acute kidney injury, and length of hospital stay. The purpose of this article is to review the advances in the endovascular repair of complex aortic aneurysms exploring the indications for treatment, preoperative evaluation, patient selection, device design, and implantation technique.

Editor's Choice - Systematic Review and Meta-Analysis of Normal Infrarenal Aortic Diameter in the General Worldwide Population and Changes in Recent Decades

OBJECTIVE

To analyse the characteristics of normal infrarenal aortic diameter (AD) in the general worldwide population, to examine changes over time, and to investigate geographical differences.

DATA SOURCES

PubMed, Cochrane Library, and Web of Science.

REVIEW METHODS

This was a systematic review and meta-analysis of studies published up to October 2020 describing infrarenal AD measured by ultrasound in the general adult population. The study was conducted in accordance with the PRISMA statement and placed no restrictions on geographical location or year of publication. Studies of individuals pre-selected for certain diseases or risk factors and opportunistic screening were excluded. A random effects model was used to estimate pooled mean AD, and meta-regression analysis was used to study the effects of determinants of AD.

RESULTS

Thirty-two studies were included, reporting data for 941 144 individuals (98% were men). The pooled mean AD was 19.4 mm (95% confidence interval [CI] 18.8 - 20.1), being 20.1 mm (95% CI 19.4 - 20.8) in men and 17.8 mm (95% CI 16.5 - 19.1) in women (p < .001). Outer edge to outer edge (OTO) caliper placement method (p = .015) and body surface area (BSA; p = .010) were significantly associated with larger AD. In men, the largest mean AD was observed in Oceania (p < .001) and the smallest in Asia (p < .020). As none of the studies collected data between 2002 and 2007, the studies were divided into two periods: 2001 and before, and 2008 and after. All recent studies were European, with the diameters being significantly smaller (p = .003) in the latter period (18.3 mm [95% CI 17.5 - 19.1] vs. 20.7 mm [95% CI 19.1 - 22.3]). In the meta-regression models, the reduction in AD over time remained significant after adjustment for potential effect modifiers such as sex, age, geographical area, body size, cardiovascular risk factors, and ultrasound method.

CONCLUSION

Mean infrarenal AD in older European adults has decreased significantly in recent decades. Male sex, BSA, and OTO ultrasound measurement method are associated with larger AD, and geographical differences were observed in men.

Editor's Choice - Cohort Study Examining the Association Between Abdominal Aortic Size and Major Adverse Cardiovascular Events in Patients with Aortic and Peripheral Occlusive and Aneurysmal Disease

OBJECTIVE

The aim of this study was to examine whether there were independent associations between abdominal aortic diameter, size index, and height index and the risk of major adverse events in patients referred for treatment of various types of aortic and peripheral occlusive and aneurysmal disease (APOAD).

METHODS

In total, 1 752 participants with a variety of APOADs were prospectively recruited between 2002 and 2020 and had a maximum abdominal aortic diameter, aortic size index (aortic diameter relative to body surface area), and aortic height index (aortic diameter relative to height) measured by ultrasound at recruitment. Participants were followed for a median of 4.6 years (interquartile range 2.0 - 8.0 years) to record outcome events, including major adverse cardiovascular events (MACE), peripheral artery surgery, abdominal aortic aneurysm (AAA) events (rupture or repair), and all cause mortality. The association between aortic size and events was assessed using Cox proportional hazard analysis. The ability of aortic size to improve risk of events classification was assessed using the net reclassification index (NRI).

RESULTS

After adjusting for other risk factors, larger aortic diameter was associated with an increased risk of MACE (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.05 - 1.31), requirement for peripheral artery surgery (HR 2.05, 95% CI 1.90 - 2.22), AAA events (HR 3.01, 95% CI 2.77 - 3.26), and all cause mortality (HR 1.20, 95% CI 1.08 - 1.32). Findings were similar for aortic size and aortic height indices. According to the NRI, all three aortic size measures significantly improved classification of risk of peripheral artery surgery and AAA events but not MACE. Aortic size index, but not aortic diameter or aortic height index, significantly improved the classification of all cause mortality risk.

CONCLUSION

Larger abdominal aortic diameter, size index, and height index are all independently associated with an increased risk of major adverse events in patients with established vascular disease.

How Does Female Sex Affect Complex Endovascular Aortic Repair? A Single Centre Cohort Study

OBJECTIVE

There is growing evidence of a female patient disadvantage in complex endovascular aortic repair using fenestrated and branched endografts (FB-EVAR) primarily related to peri-procedural events including ischaemic and access vessel complications. This study aimed to determine the impact of sex differences on treatment patterns, and in hospital outcomes in a single centre cohort.

METHODS

This was a retrospective cross sectional single centre cohort study of all consecutive FB-EVAR procedures provided to patients with asymptomatic pararenal and thoraco-abdominal aortic aneurysm (TAAA) between 1 January 2010 and 28 February 2021. Adjusted multivariable logistic regression models were developed using backward (Wald) elimination of variables to determine the independent impact of female sex on short term outcomes.

RESULTS

In total, 445 patients (24.3% females, median age 73.0 years, IQR 66, 78) were included. Female patients had a smaller aneurysm diameter, less frequent coronary artery disease (29.6% vs. 44.8%, p = .007) and history of myocardial infarction (2.8% vs. 15.4%, p < .001) when compared with males. Females were more frequently treated for TAAA than males (49.1% vs. 25.2%, p < .001). The median length of post-procedural hospital stay was 10 days in females and 9 in males. In adjusted analyses, female sex was independently associated with higher mortality (odds ratio [OR] 10.135, 95% CI 2.264 - 45.369), post-procedural complications (OR 2.500, 95% CI 1.329 - 4.702), spinal cord ischaemia (OR 4.488, 95% CI 1.610 - 12.509), sepsis (OR 4.940, 95% CI 1.379 - 17.702), and acute respiratory insufficiency (OR 3.283, 95% CI 1.015 - 10.622) after pararenal aortic aneurysm repair during the hospital stay.

CONCLUSION

In this analysis of consecutively treated patients, female sex was associated with increased in hospital mortality, peri-procedural complications, and spinal cord ischaemia after elective complex endovascular repair of pararenal aortic aneurysm, while no differences were revealed in the TAAA subgroup. These results suggest that sex related patient selection and peri-procedural management should be studied in future research.

Sex-specific criteria for repair should be utilized in patients undergoing aortic aneurysm repair

OBJECTIVE

Female patients are more likely to undergo repair of intact and ruptured abdominal aortic aneurysm (AAA) at smaller aortic diameter compared with male patients. By adjusting for inherent anatomic differences between sexes, aortic size index (ASI) and aortic height index (AHI) may provide an additional method for guiding treatment. We therefore analyzed sex-specific criteria for AAA repair using aortic diameter, ASI, and AHI.

METHODS

We identified all patients who underwent AAA repair between 2003 and 2019 in the Vascular Quality Initiative database. The Dubois and Dubois formula was used to calculate body surface area; aortic diameter was divided by body surface area to calculate ASI. Aortic diameter was divided by height to calculate AHI. Cumulative distribution curves were used to plot the proportion of patients who underwent repair of ruptured aneurysm according to aortic diameter, ASI, and AHI. Multivariable logistic regression modeling was used to identify the association of female sex with perioperative mortality and any major postoperative complication.

RESULTS

We identified 55,647 patients, of whom 12,664 were female (20%). For both intact and rupture repair, female patients were older, less likely to undergo endovascular aneurysm repair, and more likely to have comorbid conditions. Female patients underwent repair at smaller median aortic diameter compared with male patients for intact (5.4 vs 5.5 cm; P < .001) and rupture repair (6.7 vs 7.7 cm; P < .001). However, ASI was higher in female patients for both intact (3.1 vs 2.7 cm/m²; P < .001) and rupture repair (3.8 vs 3.7 cm/m²; P < .001), whereas AHI was higher in female patients for intact repair (3.3 vs 3.1 cm/m; P < .001) but lower for rupture repair (4.1 vs 4.3 cm/m; P < .001). When analyzing the cumulative distribution of rupture repair in male patients, 12% of rupture repairs were performed at an aortic diameter below 5.5 cm. To achieve the same proportion of rupture repair in female patients, the repair diameter was only 4.9 cm. However, when ASI and AHI were used, female and male patients both reached 12% of rupture repair at an ASI of 2.7 cm/m² and an AHI of 3.0 cm/m.

CONCLUSION

Our study provides data to strongly support the sex-specific 5.0-cm aortic diameter threshold suggested for repair in female patients by the Society for Vascular Surgery. The high percentage of patients undergoing rupture repair below 5.5 cm in male patients and 5.0 cm in female patients highlights the need to better identify patients at risk of rupture at smaller aortic diameters.

The Short-term Predictive Value of Vessel Wall Stiffness on Abdominal Aortic Aneurysm Growth

BACKGROUND

Abdominal aortic aneurysm (AAA) surveillance programs are currently based solely on AAA diameter. The diameter criterion alone, however, seems inadequate as small AAAs comprise 5-10 % of ruptured AAAs as well as some large AAAs never rupture. Aneurysm wall stiffness has been suggested to predict rupture and growth; this study aimed to investigate the prognostic value of AAA vessel wall stiffness for growth on prospectively collected data.

METHODS

Analysis was based on data from a randomised, placebo-controlled, multicentre trial investigating mast-cell-inhibitors to halt aneurysm growth (the AORTA trial). Systolic and diastolic AAA diameter was determined in 326 patients using electrocardiogram-gated ultrasound (US). Stiffness was calculated at baseline and after 1 year.

RESULTS

Maximum AAA diameter increased from 44.1 mm to 46.5 mm during the study period. Aneurysm growth after 1 year was not predicted by baseline stiffness (-0.003 mm/U; 95 % CI: -0.007 to 0.001 mm/U; P = 0.15). Throughout the study period, stiffness remained unchanged (8.3 U; 95 % CI: -2.5 to 19.1 U; P = 0.13) and without significant correlation to aneurysm growth (R: 0.053; P = 0.38).

CONCLUSIONS

Following a rigorous US protocol, this study could not confirm AAA vessel wall stiffness as a predictor of aneurysm growth in a 1-year follow-up design. The need for new and subtle methods to complement diameter for improved AAA risk assessment is warranted.

Ultrasound screening for abdominal aortic aneurysm in high-risk women

Background

Population-wide ultrasound screening programmes for abdominal aortic aneurysm (AAA) for men have already been established in some countries. Women account for one third of aneurysm-related mortality and are four times more likely to experience an AAA rupture than men. Whole-population screening for AAA in women is unlikely to be clinically or economically effective. The aim of this study was to determine the outcomes of a targeted AAA screening programme for women at high risk of AAA.

Method

Women aged 65–74 years deemed at high risk of having an AAA (current smokers, ex-smokers, or with a history of coronary artery disease) were invited to attend ultrasound screening (July 2016 to March 2019) for AAA in the Female Aneurysm screening STudy (FAST). Primary outcomes were attendance for screening and prevalence of AAA. Biometric data, medical history, quality of life (QoL) and aortic diameter on ultrasound imaging were recorded prospectively.

Results

Some 6037 women were invited and 5200 attended screening (86.7 per cent). Fifteen AAAs larger than 29 mm were detected (prevalence 0.29 (95 per cent c.i. 0.18 to 0.48) per cent). Current smokers had the highest prevalence (0.83 (95 per cent c.i. 0.34 to 1.89) per cent) but lowest attendance (75.2 per cent). Three AAAs greater than 5.5 cm were identified and referred for consideration of surgical repair; one woman underwent repair. There was a significant reduction in patient-reported QoL scores following screening.

Conclusion

A low prevalence of AAA was detected in high-risk women, with lowest screening uptake in those at highest risk. Screening for AAA in high-risk women may not be beneficial.

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.

Relationship between the abdominal aortic diameter and carotid atherosclerosis in middle-aged patients without established atherosclerotic cardiovascular diseases

BACKGROUND

The purpose of our research was to study the relationship between the diameter of abdominal aorta (AA) and subclinical atherosclerosis in patients without established atherosclerotic cardiovascular diseases (ASCD) in the absence of pathological enlargement of AA.

METHODS

The study included 136 patients (52.9% male, 47.1% female), median age was 51.0 (45.5; 58.0) years. The maximum diameter of AA was measured in the infrarenal region at a level between the place of origin of the lower renal artery and bifurcation in cross section. Measurement of the anteroposterior diameter of AA was carried out from the outer-to-outer edge (OTO). Also, we determined the Aortic Size Index (ASI) with respect to body surface area (BSA), using the values of BSA obtained by five different formulas validated for use in clinical practice. All patients underwent carotid duplex ultrasound scanning with assessment of degree of carotid stenosis (according to ECST criteria).

RESULTS

An increase in the anteroposterior diameter of AA was directly correlated with maximum stenosis of carotid arteries (r=0.186; P=0.030). According to the results of a logistic regression analysis an increase in the diameter of AA by 1 mm was associated with an increase in the relative risk of carotid stenosis ≥50% by 1.37 times (95% CI: 1.01-1.85; P=0.041) after adjustment. Thus, an increase in diameter of AA of more than 1.75 cm with a sensitivity of 71.4% and a specificity of 73.0% made it possible to predict the presence of stenosis of the carotid arteries ≥50%. An increase in ASI<inf>Boyd</inf> (BSA was calculated using Boyd's formula) of more than 0.84 allowed predicting the presence of stenosis of the carotid arteries ≥50% with a sensitivity of 85.7% and a specificity of 65.6%.

CONCLUSIONS

In middle-aged patients without established ASCD, the diameter of AA and ASI directly correlated with the degree of carotid stenosis (according to ECST criteria). The diameter of AA and ASI demonstrated good sensitivity and specificity for the presence of asymptomatic carotid stenosis of ≥50%.

Both Small and Large Infrarenal Aortic Size is Associated with an Increased Prevalence of Ischaemic Heart Disease

OBJECTIVE

Past studies have suggested a potential "J shaped" relationship between infrarenal aortic diameter and both cardiovascular disease (CVD) prevalence and all cause mortality. However, screening programmes have focused primarily on large (aneurysmal) aortas. In addition, aortic diameter is rarely adjusted for body size, which is particularly important for women. This study aimed to investigate specifically the relationship between body size adjusted infrarenal aortic diameter and baseline prevalence of CVD.

METHODS

A retrospective analysis was performed on a total of 4882 elderly (>50 years) participants (mean age 69.4 ± 8.9 years) for whom duplex ultrasound to assess infrarenal abdominal aortic diameters had been performed. History of CVDs, including ischaemic heart disease (IHD), and associated risk factors were collected at the time of assessment. A derivation cohort of 1668 participants was used to select cut offs at the lower and upper 12.5% tails of the aortic size distributions (aortic size index of <0.84 and >1.2, respectively), which was then tested in a separate cohort.

RESULTS

A significantly elevated prevalence of CVD, and specifically IHD, was observed in participants with both small and large aortas. These associations remained significant following adjustment for age, sex, diabetes, hypertension, dyslipidaemia, obesity (body mass index), and smoking.

CONCLUSION

The largest and smallest infrarenal aortic sizes were both associated with prevalence of IHD. In addition to identifying those with aneurysmal disease, it is hypothesised that screening programmes examining infrarenal aortic size may also have the potential to improve global CVD risk prediction by identifying those with small aortas.

Top 10 candidate aortic disease trials

Aortic pathologies such as aneurysm, dissection and trauma are relatively common and potentially fatal diseases. Over the past two decades, we have experienced unprecedented technical and medical developments in the field. Despite this, there is a great need, and great opportunities, to further explore the area. In this review, we have identified important areas that need to be further studied and selected priority aortic disease trials. There is a pressing need to update the AAA natural history and the role for endovascular AAA repair as well as to define biomarkers and genetic risk factors as well as influence of gender for development and progression of aortic disease. A key limitation of contemporary treatment strategies of AAA is the lack of therapy directed at small AAA, to prevent AAA expansion and need for surgical repair, as well as to reduce the risk for aortic rupture. Currently, the most promising potential drug candidate to slow AAA growth is metformin, and RCTs to verify or reject this hypothesis are warranted. In addition, the role of endovascular treatment for ascending pathologies and for uncomplicated type B aortic dissection needs to be clarified.

Long-Term Follow-Up of Men Invited to Participate in a Population-Based Abdominal Aortic Aneurysm Screening Program

A screening program for abdominal aortic aneurysm (AAA), inviting 65-year-old men, was started in Stockholm in 2010 (2.3 million inhabitants). The aim was to present a long-term follow-up of men participating in screening, as well as AAA repair and ruptures among nonparticipants. Demographics were collected for men with screening detected with AAA 2010 to 2016 (n = 672) and a control group with normal aortas at screening (controls, n = 237). Medical charts and regional Swedvasc (Swedish Vascular registry) data were analyzed for aortic repair for men born 1945 to 1951. Ultrasound maximum aortic diameter (AD) as well as Aortic Size Index (ASI) was recorded. Participation was 78% and prevalence of AAA was 1.2% (n = 672). Aortic repair rates correlated with high ASI and AD. During the study period, 22% of the AAA patients were treated with the elective repair; 35 men in surveillance died (5.2%), non-AAA-related causes (82.9%) dominated, followed by unknown causes among 4 (11.4%), and 2 (5.7%) possibly AAA-related deaths. Abdominal aortic aneurysm rupture rate was higher among nonparticipants (0.096% vs 0.0036%, P < .001). The low dropout rate confirms acceptability of follow-up after screening. The efficacy is shown by the much higher rupture rate among the nonparticipating men.

Pathogenic mechanisms and the potential of drug therapies for aortic aneurysm

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

Is the aortic size index relevant as a predictor of abdominal aortic aneurysm? A population-based prospective study: the Tromsø study

Objectives. The normal aortic diameter (AD) varies with gender, age and body surface area (BSA). The aortic size index (ASI) is defined as the AD divided by BSA. The primary aim of this study was to investigate if ASI is a predictor of development AAA, and to compare the predictive impact of ASI to that of the absolute AD. Design. Population-based prospective study including 4161 individuals (53.2% women) from the Tromsø study with two valid ultrasound measurements of the AD and no AAA at baseline (Tromsø 4, 1994). The primary outcome was AAA (AD ≥30 mm) in Tromsø 5 (2001). A secondary outcome was aortic growth of >5 mm over 7 years. Estimates of relative risk were calculated in logistic regression models. The main exposure variable was ASI. Adjustments were made for age, gender, smoking, body mass index, total and high-density lipoprotein (HDL) cholesterol, and hypertension. Results. In total, 124 incident AAAs (20% among women) were detected. In adjusted analyses, both ASI and AD were strong predictors of AAA, with similar results for men and women. Both ASI and AD were also significant predictors of aortic growth >5 mm. In comparison, AD was superior to ASI as a predictor of both endpoints. Conclusions. ASI was a significant predictor of both AAA development and aortic growth of >5 mm for both men and women, but not a better predictor of either outcomes compared to the AD. The role of ASI compared to the AD as a predictor of AAA development seems to be limited.

A Methodology to Quantify the Geometrical Complexity of the Abdominal Aortic Aneurysm

The abdominal aortic aneurysm (AAA) anatomy influences the technical success of the endovascular aneurysm repair (EVAR), yet very few data regarding the aortic tree angles exist in the literature. This poses great limitations in the numerical analyses of endografts, constraining their design improvement as well as the identification of their operational limitations. In this study, a matrix Φ of 10 angles was constructed for the description of the pathological region and was implemented on a large dataset of anatomies. More specifically, computed tomography angiographies from 258 patients were analysed and 10 aortic angles were calculated per case, able to adequately describe the overall AAA shape. 9 dimensional variables (i.e. diameters and lengths) were also recorded. The median and extreme values of these variables were computed providing a detailed quantification of the geometrical landscape of the AAA. Moreover, statistical analysis showed that the identified angles presented no strong correlation with each other while no lateral or anterior/posterior symmetry of the AAA was identified. These findings suggest that endograft designers are free to construct any extreme case-studies with the values provided in a mix-and-match manner. This strategy can have a powerful effect in EVAR stent graft designing, as well as EVAR planning.

Body surface area and glucose tolerance - The smaller the person, the greater the 2-hour plasma glucose

BACKGROUND

The oral glucose tolerance test (OGTT) is standardized globally with a uniform glucose load of 75 g to all adults irrespective of body size. An inverse association between body height and 2-hour postload plasma glucose (2hPG) has been demonstrated. Our aim was to evaluate the relationship between body surface area (BSA) and plasma glucose values during an OGTT.

METHODS

An OGTT was performed on 2659 individuals at increased cardiovascular risk aged between 45 and 70 years of age, who had not previously been diagnosed with diabetes or cardiovascular disease. Their BSA was calculated according to the Mosteller formula. Study subjects were divided into five BSA levels corresponding to 12.5, 25, 25, 25, and 12.5% of the total distribution.

FINDINGS

When adjusted for age, sex, waist circumference, alcohol intake, current smoking, and leisure-time physical activity, BSA level showed an inverse linear relationship with the 2hPG in all categories of glucose tolerance (p for linearity < 0.001). Moreover, the smaller the adjusted BSA of the study person, the higher the proportion of newly diagnosed type 2 diabetes based on 2hPG in the OGTT.

INTERPRETATION

Body size has a considerable impact on the findings from a standardized OGTT. Smaller persons are more likely to be diagnosed as glucose intolerant than relatively larger sized individuals.

FUNDING

This work was supported by the State Provincial Office of Western Finland, the Central Satakunta Health Federation of Municipalities, Satakunta Hospital District, and the Hospital District of Southwest Finland.

RESEARCH IN CONTEXT

Evidence before this study. We searched PubMed using the MeSH terms "glucose tolerance test", "body surface area", "body height", "body size", "glucose tolerance", "insulin resistance", "blood glucose" and "diabetes mellitus" on March 10, 2019 without language restrictions. We also used Cited Reference Search in Web of Science for relevant articles. The oral glucose tolerance test (OGTT) is standardized globally with a uniform glucose load of 75 g to all adults irrespective of body size. An inverse association between body height and 2-hour postload plasma glucose (2hPG) has been demonstrated. Several studies have shown that 2hPG predicts all-cause mortality better than elevated fasting glucose. However, body height or body surface area are not usually adjusted in epidemiological studies. It is well known that short adult stature is a risk factor for cardiovascular and all-cause mortality. Added value of this study. This is the first study to assess the relationship of body surface area and 2hPG in a typical primary care population at increased cardiovascular risk. Body surface area has a considerable impact on the result of a standardized OGTT. Smaller individuals are more likely to be diagnosed as glucose intolerant than relatively larger sized individuals. Implications of all the available evidence. There is a possibility that the diagnosis of type 2 diabetes made by an OGTT is a false positive result in a relatively small individual, and a false negative result in a relatively larger individual. Association of 2hPG concentrations and mortality may be influenced by body size as confounding factor. Given that the OGTT is a time and effort consuming test both for patients and laboratory personnel, validity of the OGTT for different body sizes should be reconsidered.

The population prevalence of undetected abdominal aortic aneurysm in New Zealand Māori

BACKGROUND

The prevalence of abdominal aortic aneurysm (AAA) in Polynesian populations such as the New Zealand Māori has not been characterized. We measured this in a large population-based sample.

METHODS

A cross-sectional population-based prevalence study was conducted as part of an AAA screening pilot; 2467 Māori men aged 54 to 74 years and 1526 women aged 65 to 74 years registered with a primary care practice in Auckland (New Zealand) were invited to be screened by abdominal ultrasound between June 2016 and March 2018. Patients with pre-existing AAA disease and those with terminal conditions or circumstances that would make them unlikely to benefit from screening were excluded. The prevalence rate of AAA in Māori women was calculated with a cutoff definition of 27 mm as well as with the normal 30-mm definition (used in men). A log-binomial regression model estimated the prevalence rate at exactly 65 years for the purpose of comparison with screened populations in the United Kingdom.

RESULTS

The crude prevalence rate of undiagnosed AAA in Māori men aged 60 to 74 years was 3.6%. In women, it was 1.7% at the 30-mm threshold and 2.3% at 27 mm. The prevalence rate at exactly 65 years of age was calculated from the log-binomial regression model to be 2.7% (confidence interval [CI], 2.0%-3.8%) in men, 0.9% (CI, 0.4%-2.2%) in women at the 30-mm threshold, and 1.5% (CI, 0.7%-3.0%) in women at the 27-mm threshold. Among smokers, the crude prevalence rates were 7.5% (CI, 4.9%-11.5%) in men and 6.9% (CI, 4.1%-11.5%) in women (30 mm+).

CONCLUSIONS

The prevalence of undiagnosed AAA in New Zealand Māori men is considerably higher than in screened populations of equivalent age in the United Kingdom and Sweden. Prevalence rates in New Zealand Māori women are close to those of screened British men. New Zealand should consider implementing a population-based screening program for Māori men and conduct further research into the health impact of screening Māori women.

A large proportion of patients with small ruptured abdominal aortic aneurysms are women and have chronic obstructive pulmonary disease

Objective

In a population-based cohort of ruptured abdominal aortic aneurysms (rAAAs), our aim was to investigate clinical, morphological and biomechanical features in patients with small rAAAs.

Methods

All patients admitted to an emergency department in Stockholm and Gotland, a region with a population of 2.1 million, between 2009–2013 with a CT-verified rupture (n = 192) were included, and morphological measurements were performed. Patients with small rAAAs, maximal diameter (Dmax) ≤ 60 mm were selected (n = 27), and matched 2:1 by Dmax, sex and age to intact AAA (iAAAs). For these patients, morphology including volume and finite element analysis-derived biomechanics were assessed.

Results

The mean Dmax for all rAAAs was 80.8 mm (SD = 18.9 mm), women had smaller Dmax at rupture (73.4 ± 18.4 mm vs 83.1 ± 18.5 mm, p = 0.003), and smaller neck and iliac diameters compared to men. Aortic size index (ASI) was similar between men and women (4.1 ± 3.1 cm/m² vs 3.8 ± 1.0 cm/m²). Fourteen percent of all patients ruptured at Dmax ≤ 60 mm, and a higher proportion of women compared to men ruptured at Dmax ≤ 60 mm: 27% (12/45) vs. 10% (15/147), p = 0.005. Also, a higher proportion of patients with a chronic obstructive pulmonary disease ruptured at Dmax ≤ 60 mm (34.6% vs 14.6%, p = 0.026). Supra-renal aortic size index (14.0, IQR 13.3–15.3 vs 12.8, IQR = 11.4–14.0) and peak wall rupture index (PWRI, 0.35 ± 0.08 vs 0.43 ± 0.11, p = 0.016) were higher for small rAAAs compared to matched iAAAs. Aortic size index, peak wall stress and aneurysm volume did not differ.

Conclusion

More than one tenth of ruptures occur at smaller diameters, women continuously suffer an even higher risk of presenting with smaller diameters, and this must be considered in surveillance programs. The increased supra-renal aortic size index and PWRI are potential markers for rupture risk, and patients under surveillance with these markers may benefit from increased attention, and potentially from timely repair.