Role of volume in small abdominal aortic aneurysm surveillance

Associations between Type 2 Diabetes Mellitus, Metabolic Traits, and Abdominal Aortic Aneurysm: A Cross-Ethnic Mendelian Randomization Analysis

BACKGROUND

Evidence suggests that type 2 diabetes mellitus (T2DM) may protect from abdominal aortic aneurysm (AAA). However, it is unclear whether a causal relationship exists between these 2 conditions and, if so, whether it remains consistent among racial groups.

METHODS

Cross-ethnic Mendelian randomization (MR) was used to examine the causal relationships between T2DM, metabolic traits, and AAA. Inverse variance weighted (IVW) was the primary analysis tool, supplemented by MR-Egger, weighted median, and MR Pleiotropy RESidual Sum and Outlier. Heterogeneity and horizontal pleiotropy were assessed using the Cochran's Q test and MR-Egger intercept, respectively.

RESULTS

According to IVW, an inverse correlation between T2DM and AAA was detected in Europeans (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.84-0.99; P = 0.034) and East Asians (OR 0.87, 95% CI 0.77-0.99; P = 0.038). Fasting glucose was inversely associated with AAA in Europeans (OR 0.56, 95% CI 0.33-0.96; P = 0.034) but not in East Asians. In Europeans, fasting insulin was a risk factor for AAA (OR 3.03, 95% CI 1.53-6.01; P = 0.001), while 2-hour glucose was protective (OR 0.67, 95% CI 0.49-0.91; P = 0.011). Glycated hemoglobin (HbA1c) had no effect. Insufficient instrumental variables prevented the evaluation of the relationships of fasting insulin, HbA1c, and 2-hour glucose with AAA in East Asians.

CONCLUSIONS

T2DM protects against AAA in Europeans and East Asians. The effects of different glucose metabolism characteristics on AAA may inform AAA treatment.

CTA-Based Radiomics and Area Change Rate Predict Infrarenal Abdominal Aortic Aneurysms Patients Events: A Multicenter Study

RATIONALE AND OBJECTIVES

Clinical assessment of abdominal aortic aneurysm (AAA) intervention and rupture risk relies primarily on maximum diameter, but studies have shown that sole dependence on diameter has limitations. CTA-based radiomics, aneurysm and lumen area change rates (AACR, LACR) are measured to predict potential AAA events.

MATERIALS AND METHODS

Between January 2017 and November 2022, 260 AAA patients from four centers who underwent two preoperative CTA examinations were included in this retrospective study. The endpoint event is defined as AAA rupture or repair. Patients were categorized into event and no-event groups based on the occurrence of endpoint event during follow-up. AACR and LACR were assessed using baseline and follow-up CTA, with radiomics features extracted from the baseline images. C-statistics and the Kaplan-Meier analysis were used to evaluate the predictive performance.

RESULTS

A total of 193 eligible infrarenal AAA patients were included, 176 (91.2%) were man and 17 (8.8%) were woman. The median follow-up was 33.4 (14.2, 57.4) months. Seven models were constructed, comprising the aneurysm-based Radscore model, lumen-based Radscore model, intraluminal thrombus (ILT)-based Radscore model, AACR model, LACR model, clinical model (including high-density lipoprotein, D-dimer, and baseline aneurysm diameter), and a merged model. On the external validation set, the C-index of seven models were 0.713 (0.574-0.853), 0.642 (0.499-0.786), 0.727 (0.600-0.854), 0.619 (0.484-0.753), 0.680 (0.530-0.830), 0.690 (0.557-0.824) and 0.760 (0.651-0.869), in that order. In the Kaplan-Meier analysis, the merged model was best-divided patients into high/low-risk groups with Log-rank p < 0.0001. The AARC and LARC between non-event and event groups have significant differences (AACR: 1.4 cm2/y vs. 2.3 cm2/y, p < 0.0001; LACR: 0.3 cm2/y vs. 1.1 cm2/y, p < 0.0001).

CONCLUSION

CTA-based radiomics, AACR and LACR have good predictive value for outcome event in infrarenal AAA patients.

The mitochondrial protease ClpP is a druggable target that controls VSMC phenotype by a SIRT1-dependent mechanism

Vascular smooth muscle cells (VSMCs), known for their remarkable lifelong phenotypic plasticity, play a pivotal role in vascular pathologies through their ability to transition between different phenotypes. Our group discovered that the deficiency of the mitochondrial protein Poldip2 induces VSMC differentiation both in vivo and in vitro. Further comprehensive biochemical investigations revealed Poldip2's specific interaction with the mitochondrial ATPase caseinolytic protease chaperone subunit X (CLPX), which is the regulatory subunit for the caseinolytic protease proteolytic subunit (ClpP) that forms part of the ClpXP complex - a proteasome-like protease evolutionarily conserved from bacteria to humans. This interaction limits the protease's activity, and reduced Poldip2 levels lead to ClpXP complex activation. This finding prompted the hypothesis that ClpXP complex activity within the mitochondria may regulate the VSMC phenotype. Employing gain-of-function and loss-of-function strategies, we demonstrated that ClpXP activity significantly influences the VSMC phenotype. Notably, both genetic and pharmacological activation of ClpXP inhibits VSMC plasticity and fosters a quiescent, differentiated, and anti-inflammatory VSMC phenotype. The pharmacological activation of ClpP using TIC10, currently in phase III clinical trials for cancer, successfully replicates this phenotype both in vitro and in vivo and markedly reduces aneurysm development in a mouse model of elastase-induced aortic aneurysms. Our mechanistic exploration indicates that ClpP activation regulates the VSMC phenotype by modifying the cellular NAD+/NADH ratio and activating Sirtuin 1. Our findings reveal the crucial role of mitochondrial proteostasis in the regulation of the VSMC phenotype and propose the ClpP protease as a novel, actionable target for manipulating the VSMC phenotype.

One-year follow-up after active aortic aneurysm sac treatment with shape memory polymer devices during endovascular aneurysm repair

OBJECTIVE

To determine the safety and efficacy of treating abdominal aortic aneurysm (AAA) sacs with polyurethane shape memory polymer (SMP) devices during endovascular aneurysm repair (EVAR), using a technique to fully treat the target lumen after endograft placement (aortic flow volume minus the endograft volume). SMP devices self-expand in the sac to form a porous scaffold that supports thrombosis throughout its structure.

METHODS

Two identical prospective, multicenter, single-arm studies were conducted in New Zealand and the Netherlands. The study population was adult candidates for elective EVAR of an infrarenal AAA (diameter of ≥55 mm in men and ≥50 mm in women). Key exclusion criteria were an inability to adequately seal a common iliac artery aneurysm, patent sac feeding vessels of >4 mm, and a target lumen volume of <20 mL or >135 mL. Target lumen volumes were estimated by subtracting endograft volumes from preprocedural imaging-based flow lumen volumes. SMP devices were delivered immediately after endograft deployment via a 6F sheath jailed in a bowed position in the sac. The primary efficacy end point was technical success, defined as filling the actual target lumen volume with fully expanded SMP at the completion of the procedure. Secondary efficacy outcome measures during follow-up were the change in sac volume and diameter, rate of type II endoleak and type I or III endoleaks, and the rate of open repair and related reinterventions, with data collection at 30 days, 6 months, and 1 year (to date). Baseline sac volumes and diameters for change in sac size analyses were determined from 30-day imaging studies. Baseline and follow-up volumes were normalized by subtraction of the endograft volume.

RESULTS

Of 34 patients treated with SMP devices and followed per protocol, 33 patients were evaluable at 1 year. Preprocedural aneurysm volume was 181.4 mL (95% confidence interval [CI], 150.7-212.1 mL) and preprocedural aneurysm diameter was 60.8 mm (95% CI, 57.8-63.9 mm). The target lumen volume was 56.3 mL (95% CI, 46.9-65.8 mL). Technical success was 100% and the ratio of SMP fully expanded volume to estimated target lumen volume was 1.4 ± 0.3. Baseline normalized sac volume and diameter were 140.7 mL (95% CI, 126.6-154.9 mL) and 61.0 mm (95% CI, 59.7-62.3 mm). The adjusted mean percentage change in normalized volume at 1 year was -28.8% (95% CI, -35.3 to -22.3%; P < .001). The adjusted mean change in sac diameter at 1 year was -5.9 mm (95% CI, -7.5 to -4.4 mm; P < .001). At 1 year, 81.8% of patients (95% CI, 64.5%-93.0%) achieved a ≥10% decrease in normalized volume and 57.6% of patients (95% CI, 39.2%-74.5%) achieved a ≥5 mm decrease in diameter. No device- or study procedure-related major adverse events occurred through 1 year after the procedure.

CONCLUSIONS

Treatment of AAA sacs with SMP devices during EVAR resulted in significant sac volume and diameter regression at 1 year with an acceptable safety profile in this prospective study.

Impact of CT-determined low kidney volume on renal function decline: a propensity score-matched analysis

OBJECTIVES

To investigate the relationship between low kidney volume and subsequent estimated glomerular filtration rate (eGFR) decline in eGFR category G2 (60-89 mL/min/1.73 m2) population.

METHODS

In this retrospective study, we evaluated 5531 individuals with eGFR category G2 who underwent medical checkups at our institution between November 2006 and October 2017. Exclusion criteria were absent for follow-up visit, missing data, prior renal surgery, current renal disease under treatment, large renal masses, and horseshoe kidney. We developed a 3D U-net-based automated system for renal volumetry on CT images. Participants were grouped by sex-specific kidney volume deviations set at mean minus one standard deviation. After 1:1 propensity score matching, we obtained 397 pairs of individuals in the low kidney volume (LKV) and control groups. The primary endpoint was progression of eGFR categories within 5 years, assessed using Cox regression analysis.

RESULTS

This study included 3220 individuals (mean age, 60.0 ± 9.7 years; men, n = 2209). The kidney volume was 404.6 ± 67.1 and 376.8 ± 68.0 cm3 in men and women, respectively. The low kidney volume (LKV) cutoff was 337.5 and 308.8 cm3 for men and women, respectively. LKV was a significant risk factor for the endpoint with an adjusted hazard ratio of 1.64 (95% confidence interval: 1.09-2.45; p = 0.02).

CONCLUSION

Low kidney volume may adversely affect subsequent eGFR maintenance; hence, the use of imaging metrics may help predict eGFR decline.

CRITICAL RELEVANCE STATEMENT

Low kidney volume is a significant predictor of reduced kidney function over time; thus, kidney volume measurements could aid in early identification of individuals at risk for declining kidney health.

KEY POINTS

• This study explores how kidney volume affects subsequent kidney function maintenance. • Low kidney volume was associated with estimated glomerular filtration rate decreases. • Low kidney volume is a prognostic indicator of estimated glomerular filtration rate decline.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

The Role of Aortic Volume in the Natural History of Abdominal Aortic Aneurysms and Post-Endovascular Aortic Aneurysm Repair Surveillance

There has been a debate about whether maximum diameter can be solely used to assess the natural history of abdominal aortic aneurysm. The aim of the present review is to collect all the available evidence on the role of abdominal aortic aneurysm (AAA) volume in the natural history of AAAs, including small untreated AAAs and AAAs treated by EVAR. The current literature appears to reinforce the role of volume as a supplementary measure for evaluating the natural history of AAA, in both intact AAAs and after EVAR. The clinical impact of AAA volume measurements remains unclear. Several studies show that volumetric analysis can assess changes in AAAs and predict successful endoluminal exclusion after EVAR more accurately than diameter. However, most studies lack strict standardized measurement criteria and well-defined outcome definitions. It remains unclear whether volumetry could replace diameter assessment in defining the risk of rupture of AAAs and identifying clinically relevant sac growth.

Comparing maximum diameter and volume when assessing the growth of small abdominal aortic aneurysms using longitudinal CTA data: cohort study

BACKGROUND

Monitoring of abdominal aortic aneurysms (AAAs) is currently based on serial measurements of maximum aortic diameter. Additional assessment of aneurysm volume has previously been proposed to possibly improve growth prediction and treatment decisions. To evaluate the use of supplementing volume measurements, the authors aimed to characterise the growth distribution of AAA volume and to compare the growth rates of the maximum diameter and volume at the patient level.

METHODS

Maximum diameter and volume were monitored every 6 months in 84 patients with small AAAs, with a total of 331 computed tomographic angiographies (with initial maximum diameters of 30-68 mm). A previously developed statistical growth model for AAAs was applied to assess the growth distribution of volume and to compare individual growth rates for volume and for maximum diameter.

RESULTS

The median (25-75% quantile) expansion in volume was 13.4 (6.5-24.7) % per year. Cube root transformed volume and maximum diameter showed a closely linear association with a within-subject correlation of 0.77. At the surgery threshold maximum diameter of 55 mm, the median (25-75% quantile) volume was 132 (103-167) ml. In 39% of subjects, growth rates for volume and maximum diameter were equivalent, in 33% growth was faster in volume and in 27% growth was faster in maximum diameter.

CONCLUSION

At the population level, volume and maximum diameter show a substantial association such that the average volume is approximately proportional to the average maximum diameter raised to a power of three. At the individual level, however, in the majority of patient's AAAs grow at different pace in different dimensions. Hence, closer monitoring of aneurysms with sub-critical diameter but suspicious morphology may benefit from complementing maximum diameter by volume or related measurements.

Associations of Tissue and Soluble LOX-1 with Human Abdominal Aortic Aneurysm

Background Indication for prophylactic surgical abdominal aortic aneurysm (AAA) repair depends on the maximal aortic diameter. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for uptake of oxidized low-density lipoprotein cholesterol and is implicated in atherosclerosis. A soluble form of LOX-1 (sLOX-1) has been discussed as a novel biomarker in coronary artery disease and stroke. Herein, we assessed the regulation of aortic LOX-1 as well as the diagnostic and risk stratification potential of sLOX-1 in patients with AAA. Methods and Results Serum sLOX-1 was assessed in a case-control study in AAA (n=104) and peripheral artery disease (n=104). sLOX-1 was not statistically different between AAA and peripheral artery disease but was higher in AAA (β=1.28, P=0.04) after adjusting for age, atherosclerosis, type 2 diabetes, prescription of statins, β-blockers, ACE inhibitors, and therapeutic anticoagulation. sLOX-1 was not associated with the aortic diameter, AAA volume, or the thickness of the intraluminal thrombus. Aortic LOX-1 mRNA expression tended to be higher in AAA when compared with disease, and expression was positively associated with cleaved caspase-3, smooth muscle actin, collagen, and macrophage content. Conclusions In AAA, sLOX-1 was differently affected by age, cardiometabolic diseases, and corresponding medical therapies. Comparison with nonatherosclerotic disease would be beneficial to further elucidate the diagnostic potential of sLOX-1, although it was not useful for risk stratification. Aneurysmal LOX-1 mRNA expression was increased and positively associated with smooth muscle cells and collagen content, suggesting that LOX-1 is eventually not deleterious in human AAA and could counteract AAA rupture.

Regulation of CD163 Receptor in Patients with Abdominal Aortic Aneurysm and Associations with Antioxidant Enzymes HO-1 and NQO1

Red blood cells are found within the abdominal aortic aneurysm (AAA), in the intraluminal thrombus (ILT), and in neovessels. Hemolysis promotes aortic degeneration, e.g., by heme-induced reactive oxygen species formation. To reduce its toxicity, hemoglobin is endocytosed by the CD163 receptor and heme is degraded by heme oxygenase-1 (HO-1). A soluble form (sCD163) is discussed as an inflammatory biomarker representing the activation of monocytes and macrophages. HO-1 and NAD(P)H quinone dehydrogenase 1 (NQO1) are antioxidant genes that are induced by the Nrf2 transcription factor, but their regulation in AAA is only poorly understood. The aim of the present study was to analyze linkages between CD163, Nrf2, HO-1, and NQO1 and to clarify if plasma sCD163 has diagnostic and risk stratification potential. Soluble CD163 was 1.3-fold (p = 0.015) higher in AAA compared to patients without arterial disease. The difference remained significant after adjusting for age and sex. sCD163 correlated with the thickness of the ILT (r_s = 0.26; p = 0.02) but not with the AAA diameter or volume. A high aneurysmal CD163 mRNA was connected to increases in NQO1, HMOX1, and Nrf2 mRNA. Further studies are needed to analyze the modulation of the CD163/HO-1/NQO1 pathway with the overall goal of minimizing the detrimental effects of hemolysis.

Abdominal Aortic Aneurysm Diameter versus Volume: A Systematic Review

Recently, AAA volume measurement has been proposed as a potentially valuable surveillance method in situations when diameter measurement might fail.

OBJECTIVE

The aim of this systematic review was to analyze the results of previous studies comparing AAA diameter and volume measurements.

METHODS

A systematic search in PubMed, Cochrane, and EMBASE databases was performed to identify studies investigating the use of diameter and volume measurements in AAA diagnosis and prognosis in English, German, and Russian, published until December 2022. The manuscripts were reviewed by three researchers and scored on the quality of the research using MINORS criteria.

RESULTS

After screening 752 manuscripts, 19 studies (n = 1690) were included. The majority (n = 17) of the manuscripts appeared to favor volume. It is, however, important to highlight the heterogeneity of methodologies and lack of standardized protocol for measuring both volume and diameter in the included studies, which hindered the interpretation of the results.

CONCLUSIONS

The clinical relevance of abdominal aortic aneurysm volume measurement is still unclear, although studies show favorable and promising results for volumetric changes in AAA, especially in follow-up after EVAR.

Contrast-enhanced CT radiomics improves the prediction of abdominal aortic aneurysm progression

OBJECTIVES

To determine if three-dimensional (3D) radiomic features of contrast-enhanced CT (CECT) images improve prediction of rapid abdominal aortic aneurysm (AAA) growth.

METHODS

This longitudinal cohort study retrospectively analyzed 195 consecutive patients (mean age, 72.4 years ± 9.1) with a baseline CECT and a subsequent CT or MR at least 6 months later. 3D radiomic features were measured for 3 regions of the AAA, viz. the vessel lumen only; the intraluminal thrombus (ILT) and aortic wall only; and the entire AAA sac (lumen, ILT, and wall). Multiple machine learning (ML) models to predict rapid growth, defined as the upper tercile of observed growth (> 0.25 cm/year), were developed using data from 60% of the patients. Diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve (AUC) in the remaining 40% of patients.

RESULTS

The median AAA maximum diameter was 3.9 cm (interquartile range [IQR], 3.3-4.4 cm) at baseline and 4.4 cm (IQR, 3.7-5.4 cm) at the mean follow-up time of 3.2 ± 2.4 years (range, 0.5-9 years). A logistic regression model using 7 radiomic features of the ILT and wall had the highest AUC (0.83; 95% confidence interval [CI], 0.73-0.88) in the development cohort. In the independent test cohort, this model had a statistically significantly higher AUC than a model including maximum diameter, AAA volume, and relevant clinical factors (AUC = 0.78, 95% CI, 0.67-0.87 vs AUC = 0.69, 95% CI, 0.57-0.79; p = 0.04).

CONCLUSION

A radiomics-based method focused on the ILT and wall improved prediction of rapid AAA growth from CECT imaging.

KEY POINTS

• Radiomic analysis of 195 abdominal CECT revealed that an ML-based model that included textural features of intraluminal thrombus (if present) and aortic wall improved prediction of rapid AAA progression compared to maximum diameter. • Predictive accuracy was higher when radiomic features were obtained from the thrombus and wall as opposed to the entire AAA sac (including lumen), or the lumen alone. • Logistic regression of selected radiomic features yielded similar accuracy to predict rapid AAA progression as random forests or support vector machines.

One-year volume growth of abdominal aortic aneurysms measured by extended field-of-view ultrasound

BACKGROUND

Measurement of volume has the potential to detect subtle growth not recognized in the current surveillance paradigm of abdominal aortic aneurysms (AAAs). Currently available three-dimensional ultrasound allows for estimation of AAA volume, but for most patients, the AAA extends beyond the ultrasound field-of-view and only allows visualization of a partial AAA volume. A new extended field-of-view three-dimensional ultrasound protocol (XFoV US) has been found to improve the proportion of patients with visualization of the full AAA volume.

METHODS

To investigate the applicability of the XFoV US protocol in estimating AAA volume growth in follow-up, 86 patients with AAAs were recruited from the surveillance program at a university hospital. All were imaged by XFoV US at baseline and at one-year follow-up.

RESULTS

Assessment of full volume, based on visualization of the AAA neck and bifurcation at both baseline and one-year follow-up, was achieved in 67/86 (78%) of patients. One-year mean growth in maximum diameter was 2.8 mm (6%/year), in centerline length 2.9 mm (4%/year), and in volume 15.9 mL (19%/year). In 17/67 (25%) of patients, volume growth was detected in diameter-stable AAAs. Baseline XFoV US volume was associated with one-year AAA volume growth, while, conversely, maximum baseline diameter was not associated with one-year AAA diameter growth.

CONCLUSIONS

This study concludes that the XFoV US protocol provides a safe and repeatable modality for assessing AAA volume growth, and that AAA volume is a promising predictive measure of AAA growth.

Rupture risk parameters upon biomechanical analysis independently change from vessel geometry during abdominal aortic aneurysm growth

Objective

The indication for abdominal aortic aneurysm (AAA) repair is based on a diameter threshold. However, mechanical properties, such as peak wall stress (PWS) and peak wall rupture index (PWRI), influence the individual rupture risk. This study aims to correlate biomechanical and geometrical AAA characteristics during aneurysm growth applying a new linear transformation-based comparison of sequential imaging.

Methods

Patients with AAA with two sequential computed tomography angiographies (CTA) were identified from a single-center aortic database. Patient characteristics included age, gender, and comorbidities. Semiautomated segmentation of CTAs was performed using Endosize (Therenva) for geometric variables (diameter, neck configuration, α/β angle, and vessel tortuosity) and for finite element method A4 Clinics Research Edition (Vascops) for additional variables (intraluminal thrombus [ILT]), vessel volume, PWS, PWRI). Maximum point coordinates from at least one CTA 6 to 24 months before their final were predicted for the final preoperative CTA using linear transformation along fix and validation points to estimate spatial motion. Pearson's correlation and the t test were used for comparison.

Results

Thirty-two eligible patients (median age, 70 years) were included. The annual AAA growth rate was 3.7 mm (interquartile range [IQR], 2.25-5.44; P < .001) between CTs. AAA (+17%; P < .001) and ILT (+43%; P < .001) volume, maximum ILT thickness (+35%; P < .001), β angle (+1.96°; P = .017) and iliac tortuosity (+0.009; P = .012) increased significantly. PWS (+12%; P = .0029) and PWRI (+16%; P < .001) differed significantly between both CTAs. Both mechanical parameters correlated most significantly with the AAA volume increase (r = 0.68 [P < .001] and r = 0.6 [P < .001]). Changes in PWS correlated best with the aneurysm neck configuration. The spatial motion of maximum ILT thickness was 14.4 mm (IQR, 7.3-37.2), for PWS 8.4 mm (IQR, 3.8-17.3), and 11.5 mm (IQR, 5.9-31.9) for PWRI. Here, no significant correlation with any of the aforementioned parameters, patient age, or time interval between CTs were observed.

Conclusions

PWS correlates highly significant with vessel volume and aneurysm neck configuration. Spatial motion of maximum ILT thickness, PWS, and PWRI is detectable and predictable and might expose different aneurysm wall segments to maximum stress throughout aneurysm growth. Linear transformation could thus add to patient-specific rupture risk analysis.

Clinical Relevance

Abdominal aortic aneurysm rupture risk assessment is a key feature in future individualized therapy approaches for patients, since more and more data are obtained concluding a heterogeneous disease entity that might not be addressed ideally looking only at diameter enlargement. The approach presented in this pilot study demonstrates the feasibility and importance of measuring peak wall stress and rupture risk indices based on predicted and actual position of maximum stress points including intraluminal thrombus.