Ultrasound diagnostics of the abdominal aorta: English version

Temporal Pattern Analysis of Ultrasound Surveillance Data in Vascular Connective Tissue Disorders

BACKGROUND

Ehlers-Danlos syndrome (EDS), Marfan syndrome (MFS), and Loeys-Dietz syndrome (LDS) are connective tissue disorders frequently associated with vascular aneurysm formation, dissections, and subsequent major complications. Regular imaging surveillance is recommended for these conditions. However, no guidelines currently exist regarding imaging modality or surveillance intervals.

METHODS

This retrospective single-center observational study analyzed clinical and imaging data of patients attending an outpatient clinic for vascular connective tissue disorders between August 2008 and January 2024. Imaging (1424 data points in total) and clinical data were extracted from electronic health records. Analysis primarily included a comparison of vessel diameter progression across imaging modalities, with an additional review of the clinical history of vascular events.

RESULTS

In total, 19 patients with vascular connective tissue disorders (vCTDs) underwent consultations at our outpatient clinic. Nine (47.4%) patients experienced vascular events, while two (10.5%) passed away during the study period. Multimodal imaging surveillance revealed a tendency towards arterial diameter increase. Consistent ultrasound monitoring provided more reliable diameter progression data for the same arterial segment than a combination of imaging modalities. Temporal analysis indicated a tendency for the continuous growth of the abdominal aorta, the common and internal carotid artery, and the common femoral and popliteal artery.

CONCLUSION

The study highlights the importance of standardized, modality-specific imaging protocols in monitoring patients with vCTDs. The variability in disease progression among these patients further complicates surveillance strategies, contemplating the need for individualized approaches. Further research and prospective multicenter studies are required to refine and improve monitoring protocols.

Fast strain mapping in abdominal aortic aneurysm wall reveals heterogeneous patterns

Abdominal aortic aneurysm patients are regularly monitored to assess aneurysm development and risk of rupture. A preventive surgical procedure is recommended when the maximum aortic antero-posterior diameter, periodically assessed on two-dimensional abdominal ultrasound scans, reaches 5.5 mm. Although the maximum diameter criterion has limited ability to predict aneurysm rupture, no clinically relevant tool that could complement the current guidelines has emerged so far. In vivo cyclic strains in the aneurysm wall are related to the wall response to blood pressure pulse, and therefore, they can be linked to wall mechanical properties, which in turn contribute to determining the risk of rupture. This work aimed to enable biomechanical estimations in the aneurysm wall by providing a fast and semi-automatic method to post-process dynamic clinical ultrasound sequences and by mapping the cross-sectional strains on the B-mode image. Specifically, the Sparse Demons algorithm was employed to track the wall motion throughout multiple cardiac cycles. Then, the cyclic strains were mapped by means of radial basis function interpolation and differentiation. We applied our method to two-dimensional sequences from eight patients. The automatic part of the analysis took under 1.5 min per cardiac cycle. The tracking method was validated against simulated ultrasound sequences, and a maximum root mean square error of 0.22 mm was found. The strain was calculated both with our method and with the established finite-element method, and a very good agreement was found, with mean differences of one order of magnitude smaller than the image spatial resolution. Most patients exhibited a strain pattern that suggests interaction with the spine. To conclude, our method is a promising tool for investigating abdominal aortic aneurysm wall biomechanics as it can provide a fast and accurate measurement of the cyclic wall strains from clinical ultrasound sequences.

Reference values for paediatric abdominal aorta on B-mode ultrasound - an outer-to-outer methodology

BACKGROUND

B-mode ultrasound is versatile and safe. The sequelae of aortic disorders in children range from stunted growth in hypoplasia to 90% fatality in ruptured aneurysms. Thus, age-based reference values are necessary for early detection of abnormal aortic dimensions.

OBJECTIVE

To create age-based reference values of paediatric aorta diameters from B-mode ultrasound using the outer-to-outer method.

MATERIALS AND METHODS

A retrospective review was done of records of peak systolic anteroposterior aortic diameters, obtained during abdominal ultrasound in children ages 2 days to 17 years between January 2016 and December 2019. Cases were grouped into five age groups.

RESULTS

A total of 643 cases (49% female) were recruited into the study. Only 488 cases (76%) had values for the proximal, mid and distal aorta. The cumulative mean age was 9.5±5.1 years while the mean aortic diameter ranged from 0.3 cm to 1.8 cm. Tables of aortic diameters and reference ranges are presented. There was no significant sex difference. Significant positive correlation was only seen between age and aortic diameters (Pearson's r ranges from 0.66 to 0.91).

CONCLUSION

An age-based paediatric aortic reference table from B-mode ultrasound using outer-to-outer measurement in a Nigerian population is reported.

Identification of key monocytes/macrophages related gene set of the early-stage abdominal aortic aneurysm by integrated bioinformatics analysis and experimental validation

Objective

Abdominal aortic aneurysm (AAA) is a lethal peripheral vascular disease. Inflammatory immune cell infiltration is a central part of the pathogenesis of AAA. It’s critical to investigate the molecular mechanisms underlying immune infiltration in early-stage AAA and look for a viable AAA marker.

Methods

In this study, we download several mRNA expression datasets and scRNA-seq datasets of the early-stage AAA models from the NCBI-GEO database. mMCP-counter and CIBERSORT were used to assess immune infiltration in early-stage experimental AAA. The scRNA-seq datasets were then utilized to analyze AAA-related gene modules of monocytes/macrophages infiltrated into the early-stage AAA by Weighted Correlation Network analysis (WGCNA). After that, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis for the module genes was performed by ClusterProfiler. The STRING database was used to create the protein-protein interaction (PPI) network. The Differentially Expressed Genes (DEGs) of the monocytes/macrophages were explored by Limma-Voom and the key gene set were identified. Then We further examined the expression of key genes in the human AAA dataset and built a logistic diagnostic model for distinguishing AAA patients and healthy people. Finally, real-time quantitative polymerase chain reaction (RT-qPCR) and Enzyme Linked Immunosorbent Assay (ELISA) were performed to validate the gene expression and serum protein level between the AAA and healthy donor samples in our cohort.

Results

Monocytes/macrophages were identified as the major immune cells infiltrating the early-stage experimental AAA. After pseudocell construction of monocytes/macrophages from scRNA-seq datasets and WGCNA analysis, four gene modules from two datasets were identified positively related to AAA, mainly enriched in Myeloid Leukocyte Migration, Collagen-Containing Extracellular matrix, and PI3K-Akt signaling pathway by functional enrichment analysis. Thbs1, Clec4e, and Il1b were identified as key genes among the hub genes in the modules, and the high expression of Clec4e, Il1b, and Thbs1 was confirmed in the other datasets. Then, in human AAA transcriptome datasets, the high expression of CLEC4E, IL1B was confirmed and a logistic regression model based on the two gene expressions was built, with an AUC of 0.9 in the train set and 0.79 in the validated set. Additionally, in our cohort, we confirmed the increased serum protein levels of IL-1β and CLEC4E in AAA patients as well as the increased expression of these two genes in AAA aorta samples.

Conclusion

This study identified monocytes/macrophages as the main immune cells infiltrated into the early-stage AAA and constructed a logistic regression model based on monocytes/macrophages related gene set. This study could aid in the early diagnostic of AAA.

Outcomes of Small Incidental Abdominal Aortic Aneurysms in Octogenarian and Nonagenarian Patients in Northern Spain

OBJECTIVE

Greater population life expectancy and consistent improvement in diagnostic techniques have increased the diagnosis of abdominal aortic aneurysms (AAAs) in the elderly population. The aim was to study the natural history of small (< 55 mm) incidental AAAs in octogenarian and nonagenarian patients to assess the need for follow up and/or invasive treatment.

METHODS

This was a retrospective analysis of a prospective registry. Patients ≥ 80 years old at the time of diagnosis of a < 55 mm AAA in 1988-2018 were selected. Clinical and anatomical characteristics were registered. Patients were divided in three groups: 30 - 39 mm, 40 - 49 mm, and 50 - 54 mm AAA. The outcome variables were aorto-iliac rupture, AAA reaching a surgical threshold (≥ 55 mm), and death. A descriptive statistical analysis was performed and life tables, Kaplan-Meier curves, and uni- and multivariable Cox regression were used.

RESULTS

Three hundred and ten patients were included, 256 (82.6%) men, with mean index age of 84.5 years (standard deviation [SD] 3.5), and median follow up of 37.9 months (interquartile range [IQR] 18.2 - 65.4). Eighteen (5.8%) AAAs ruptured; four of these patients were operated on and only one survived. Sixty-two (20%) AAA reached a surgical size; eight were repaired electively, with 0% early mortality. The survival rates were 81%, 70%, and 38% at one, two, and five years. The rupture rates were 1%, 2%, and 6% and the AAAs reaching surgical threshold were 1%, 4%, and 19% for the same time periods. AAA size < 40 mm was an independent protective factor from rupture (0.13; 95% confidence interval [CI] 0.03 - 0.48), reaching surgical threshold (0.08; 95% CI 0.04 - 0.16) and death (0.63; 95% CI 0.42 - 0.95).

CONCLUSION

The risk of late rupture of small incidental AAA diagnosed in octogenarian and nonagenarian patients is very small, especially when the AAA is < 40 mm in diameter. In contrast, global mortality is high. Conservative management seems sensible, with strict selection of the patients who would benefit from follow up and eventual repair.

Screening Older Adult Men for Abdominal Aortic Aneurysm: A Scoping Review

Abdominal aortic aneurysm (AAA) is a potentially fatal condition predominantly affecting older adult men (60 years or over). Based on evidence, preventative health-care guidelines recommend screening older males for AAA using ultrasound. In attempts to reduce AAA mortality among men, screening has been utilized for early detection in some Western countries including the UK and Sweden. The current scoping review includes 19 empirical studies focusing on AAA screening in men. The findings from these studies highlight benefits and potential harms of male AAA screening. The benefits of AAA screening for men include decreased incidence of AAA rupture, decreased AAA mortality, increased effectiveness of elective AAA repair surgery, and cost-effectiveness. The potential harms of AAA screening included lack of AAA mortality reduction, negative impacts on quality of life, and inconsistent screening eligibility criteria being applied by primary care practitioners. The current scoping review findings are discussed to suggest changes to AAA screening guidelines and improve policy and practice.

Identification of a Plasma Microrna Signature as Biomarker of Subaneurysmal Aortic Dilation in Patients with High Cardiovascular Risk

Patients with subaneurysmal aortic dilation (SAD; 25–29 mm diameter) are likely to progress to true abdominal aortic aneurysm (AAA). Despite these patients having a higher risk of all-cause mortality than subjects with aortic size <24 mm, early diagnostic biomarkers are lacking. MicroRNAs (miRs) are well-recognized potential biomarkers due to their differential expression in different tissues and their stability in blood. We have investigated whether a plasma miRs profile could identify the presence of SAD in high cardiovascular risk patients. Using qRT-PCR arrays in plasma samples, we determined miRs differentially expressed between SAD patients and patients with normal aortic diameter. We then selected 12 miRs to be investigated as biomarkers by construction of ROC curves. A total of 82 significantly differentially expressed miRs were found by qPCR array, and 12 were validated by qRT-PCR. ROC curve analyses showed that seven selected miRs (miR-28-3p, miR-29a-3p, miR-93-3p, miR-150-5p, miR-338-3p, miR-339-3p, and miR-378a-3p) could be valuable biomarkers for distinguishing SAD patients. MiR-339-3p showed the best sensitivity and specificity, even after combination with other miRs. Decreased miR-339-3p expression was associated with increased aortic abdominal diameter. MiR-339-3p, alone or in combination with other miRs, could be used for SAD screening in high cardiovascular risk patients, helping to the early diagnosis of asymptomatic AAA.

Ultrasonography for Preoperative Diagnosis of Retroperitoneal Fibrosis

This study aimed to assess the application of ultrasonography for preoperative diagnosis of retroperitoneal fibrosis (RPF). A total of 51 patients with clinically suspected RPF underwent transabdominal ultrasonography and ultrasound-guided histopathologic biopsy (tAU-UGHB). Retroperitoneal fibrosis was diagnosed in 35 patients; of these, 31 cases (88.6%) received a diagnosis using tAU-UGHB. The ultrasonographic images mainly showed solid, irregular isoechoic masses, which were present behind the retroperitoneum and surrounded the abdominal aorta, inferior vena cava, and ureters and had clear borders with the encapsulated structures. Compared with other retroperitoneal lesions, RPF lesions were mainly located below the initial level of the renal artery, and their internal flow signals were not rich (P < 0.05). Retroperitoneal fibrosis had characteristic ultrasonographic features, and color Doppler ultrasound-guided biopsy could be positioned accurately, safely, and efficiently; therefore, tAU-UGHB can be used as an effective modality for preoperative diagnosis of RPF.

Epidemiology, Clinical Features, and Prescribing Patterns of Aortic Aneurysm in Asian Population From 2005 to 2011

Aortic aneurysm (AA) is a leading cause of death in Asia and the world. The prevalence in Western countries is around 1.3% to 8%. However, it is still unclear about the incidence, prevalence, and mortality of AA in Asian population. The aim of this study is to investigate the epidemiology of AA for all subtypes in Taiwan, and describe the clinical features and prescribing patterns for AA population.A population-based study was conducted using information from National Health Insurance Research Database (NHIRD) in Taiwan. Patients who were diagnosed with AA and also received computed tomography (CT) were included in this study. Incidence, prevalence, and mortality were calculated in each year during 2005 to 2011. Prevalent comorbidities and prescribing patterns were both evaluated among study population.The average annual incidence of AA in Taiwan was 7.35 per 100,000 population, and the prevalence was 29.04 per 100,000 population. It showed an increased trend of incidence from 2005 to 2011, so as prevalence and mortality. The incidence was associated with age and sex difference. It was much higher in those older than 65 years, especially for male. Hypertension, coronary artery disease (CAD), and chronic obstructive pulmonary disease (COPD) were prevalent comorbidities. Eighty-eight percentages of patients were prescribed antihypertensive agents in acute phase, where 61.4% of calcium channel blocker (CCB) was the most one.Our study found that incidence of AA was lower in Taiwan than in other countries. Nevertheless, it showed an increased trend of AA disease for incidence, prevalence, and also mortality during 2005 to 2011.