Medical treatments for abdominal aortic aneurysm: an overview of clinical trials.

INTRODUCTION: Abdominal aortic aneurysm is a progressive, segmental, abdominal aortic dilation associated with a high mortality rate. Abdominal aortic aneurysms with diameters larger than 55 mm are associated with a high risk of rupture, and the most effective treatment options are surgical repair. Close observation and lifestyle adjustments are recommended for smaller abdominal aortic aneurysms with lower rupture risk. The development of medical therapies that limit or prevent the progression, expansion, and eventual rupture of abdominal aortic aneurysms remains an unmet clinical need. AREAS COVERED: This review provides an overview of completed and ongoing clinical trials examining the efficacies of various drug classes, including antibiotics, antihypertensive drugs, hypolipidemic drugs, hypoglycemic drugs, and other potential therapies for abdominal aortic aneurysms. A search of PubMed, Web of Science, Clinical Trials, and another six clinical trial registries was conducted in January 2024. EXPERT OPINION: None of the drugs have enough evidence to indicate that they can effectively inhibit the dilation of abdominal aortic aneurysm. More clinical trial data is required to support the efficacy of propranolol. Future research should also explore different drug delivery mechanisms, such as nanoparticles, to elevate drug concentration at the aneurysm wall.

Artificial intelligence-driven multiomics predictive model for abdominal aortic aneurysm subtypes to identify heterogeneous immune cell infiltration and predict disease progression.

BACKGROUND: Abdominal aortic aneurysm (AAA) poses a significant health risk and is influenced by various compositional features. This study aimed to develop an artificial intelligence-driven multiomics predictive model for AAA subtypes to identify heterogeneous immune cell infiltration and predict disease progression. Additionally, we investigated neutrophil heterogeneity in patients with different AAA subtypes to elucidate the relationship between the immune microenvironment and AAA pathogenesis. METHODS: This study enrolled 517 patients with AAA, who were clustered using k-means algorithm to identify AAA subtypes and stratify the risk. We utilized residual convolutional neural network 200 to annotate and extract contrast-enhanced computed tomography angiography images of AAA. A precise predictive model for AAA subtypes was established using clinical, imaging, and immunological data. We performed a comparative analysis of neutrophil levels in the different subgroups and immune cell infiltration analysis to explore the associations between neutrophil levels and AAA. Quantitative polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay were performed to elucidate the interplay between CXCL1, neutrophil activation, and the nuclear factor (NF)-κB pathway in AAA pathogenesis. Furthermore, the effect of CXCL1 silencing with small interfering RNA was investigated. RESULTS: Two distinct AAA subtypes were identified, one clinically more severe and more likely to require surgical intervention. The CNN effectively detected AAA-associated lesion regions on computed tomography angiography, and the predictive model demonstrated excellent ability to discriminate between patients with the two identified AAA subtypes (area under the curve, 0.927). Neutrophil activation, AAA pathology, CXCL1 expression, and the NF-κB pathway were significantly correlated. CXCL1, NF-κB, IL-1ß, and IL-8 were upregulated in AAA. CXCL1 silencing downregulated NF-κB, interleukin-1ß, and interleukin-8. CONCLUSION: The predictive model for AAA subtypes demonstrated accurate and reliable risk stratification and clinical management. CXCL1 overexpression activated neutrophils through the NF-κB pathway, contributing to AAA development. This pathway may, therefore, be a therapeutic target in AAA.

The Use of Pressure Recording Analytical Method in Patients Undergoing Endovascular Repair for Abdominal Aortic Aneurysm: The Impact on Clinical Decisions for the Appropriate Postoperative Setting and Cost-effective Analysis.

OBJECTIVE: To analyze the use of the Pressure Recording Analytical Method (PRAM), an hemodynamic monitoring system, in evaluating intraoperative and postoperative hemodynamic instability in patients undergoing endovascular repair for abdominal aortic aneurysm, and to evaluate if the decision to refer patients to a ordinary ward or to a Cardiac Step-Down Unit (CSDU) after the intervention on the basis of intraoperative hemodynamic monitoring could be more cost-effective. MATERIALS AND METHODS: After preoperative clinical evaluation, 44 patients were divided in this non-randomised study into two groups according to their postoperative destination: Group 1-ward (N=22) and Group 2-CSDU (N=22). All patients underwent monitoring with PRAM during the intervention and in the 24 postoperative hours, measuring several indices of myocardial contractility and other hemodynamic variables. RESULTS: According to the variability of two parameters, Stroke Volume Variation and Pulse Pressure Variation, patients were classified as stable or unstable. Unstable patients showed a significant alteration in several hemodynamic indices, in comparison to stable ones. According to the intraoperative monitoring, eight high risk patients could have been sent to an ordinary ward due to their stability, with a reduction in the improper use of CSDU and, consequently, in costs. CONCLUSIONS: Hemodynamic monitoring with PRAM can be useful in these patients, both for intraoperative management and for the choice of the more appropriate postoperative setting, possibly reducing the improper use of CSDU for hemodynamically stable patients who are judged to be at high risk preoperatively, and re-evaluating low surgical risk patients with an unstable intraoperative pattern, with a possible reduction in costs.

Aorto-uni-iliac stent grafts without crossover fem-fem bypass for treatment of abdominal aortic aneurysms: A report of two cases.

INTRODUCTION AND IMPORTANCE: Arterial aneurysm is a serious condition caused by weakened arterial walls. Aorto-uni-iliac (AUI) and femorofemoral bypass are safe and effective options for managing abdominal aortic aneurysm (AAA). However, fem-fem bypass leads to longer surgical procedures and introduces additional risks such as graft infection, occlusion, wound complications, and peripheral vascular problems. This report highlights two successful cases of AAA management using the AUI approach without the need for fem-fem bypass. CASE PRESENTATION: Two male patients, both aged about 70, presented at our medical facility complaining of abdominal pain. Investigations unveiled an approximately 10-cm AAA that was previously undetected. Subsequently, we performed an elective AUI procedure without fem-fem bypass, marking the first instance of this technique being employed in Iran successfully. CLINICAL DISCUSSION: The placement of an AUI stent graft is generally less technically demanding compared to that of a standard bifurcated graft, especially when anatomical constraints are severe, making the latter difficult or even impossible to deploy. Beside the longer duration of stent deployment, sometimes we encounter contralateral complications to cannulate the main body. The AUI is typically used in emergency situations or when the distal aorta's internal diameter is small. The femoral-femoral bypass is advised in nearly all circumstances. CONCLUSION: AUI stent grafts are still a viable option for treatments of AAA, especially in cases of severe aortoiliac occlusive disease or comorbidities. AUI without crossover bypass is a viable option in the patients who have stenosis of contralateral iliac artery.

Low-profile versus standard-profile stent grafts in the treatment of abdominal aortic aneurysm: a case-matched study.

Introduction: Endovascular aortic repair (EVAR) is nowadays a widespread method of managing abdominal aortic aneurysm (AAA). Low-profile stent grafts (LPSGs) enable treatment of patients with complex and anatomically challenging aneurysms, and facilitate a percutaneous and thus less invasive procedure. Aim: To assess the outcomes of EVAR with low-profile versus standard-profile stent grafts (SPSGs). Material and methods: Thirty-one patients with abdominal aortic aneurysms (AAA) were treated by endovascular aortic repair (EVAR) using LPSGs. The control group of patients treated with SPSGs was matched with MedCalc software. The clinical records and the preoperative and follow-up computed tomography angiography of patients who underwent endovascular treatment of AAA were included in this study. Results: Patients in the LPSG group had significantly more often low access vessel diameter (< 6 mm) compared to the SPSG group (38.7% vs. 6.7%, p = 0.003). In 1-year follow-up, there was no rupture, no infection, no conversion to open repair and no aneurysm-related death. Five secondary interventions were necessary in the SPSG group and only 1 in the LPSG group (p = 0.09). Type of stent graft was not a risk factor of perioperative complications, presence of endoleak or reintervention (p > 0.05). Risk factors for perioperative complications were COPD and conical neck (OR = 6.3, 95% CI: 1.5-25, p = 0.01 and OR = 6.2, 95% CI: 1-39.76, p = 0.04). The risk factor for endoleak was lower maximal aneurysm diameter. The risk factor for reintervention was proximal neck diameter (OR = 0.77, 95% CI: 0.-0.97, p = 0.03). Conclusions: Our study showed that use of LPSGs is a safe and viable method for patients with narrow access vessels who are not eligible for standard-profile systems.

Single-cell RNA sequencing reveals that NRF2 regulates vascular smooth muscle cell phenotypic switching in abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a life-threatening disease characterized by extensive membrane destruction in the vascular wall that is closely associated with vascular smooth muscle cell (VSMC) phenotypic switching. A thorough understanding of the changes in regulatory factors during VSMC phenotypic switching is essential for managing AAA therapy. In this study, we revealed the impact of NRF2 on the modulation of VSMC phenotype and the development of AAA based on single-cell RNA sequencing analysis. By utilizing a murine model of VSMC-specific knockout of nuclear factor E2-related factor 2 (NRF2), we observed that the absence of NRF2 in VSMCs exacerbated AAA formation in an angiotensin II-induced AAA model. The downregulation of NRF2 promoted VSMC phenotypic switching, leading to an enhanced inflammatory response. Through genome-wide transcriptome analysis and loss- or gain-of-function experiments, we discovered that NRF2 upregulated the expression of VSMC contractile phenotype-specific genes by facilitating microRNA-145 (miR-145) expression. Our data identified NRF2 as a novel regulator involved in maintaining the VSMC contractile phenotype while also influencing AAA formation through an miR-145-dependent regulatory mechanism.

Late Open Abdominal Aneurysm Reconstruction and Graft Salvage in a Patient With Persistent Endoleak Type II Following Endovascular Aneurysm Repair.

This study highlights a case of late open conversion repair (OCR) for persistent Type II endoleak after endovascular aneurysm repair (EVAR), presenting a 78-year-old male with a history of EVAR for an infrarenal abdominal aortic aneurysm. Despite conservative management of the initial endoleak, the aneurysm sac's progressive growth necessitated open reconstruction to salvage the graft. Successful postoperative outcomes emphasize the critical need for meticulous intervention strategies and surveillance in managing persistent Type II endoleaks. This case underlines the importance of a tailored approach, leveraging both endovascular and open surgical techniques, to optimize long-term outcomes and prevent aneurysm rupture in complex cases.

A prospective longitudinal study of risk factors for abdominal aortic aneurysm.

The aim of this study was to identify risk factors for abdominal aortic aneurysm (AAA) from the largest Welsh screening cohort to date. Patients were recruited from 1993 (to 2015) as part of the South East Wales AAA screening programme through general practitioners. Demographic data and risk factors were collected by means of a self-report questionnaire. Statistical tests were performed to determine whether associations could be observed between AAA and potential risk factors. Odds ratios (OR) were also calculated for each of the risk factors identified. A total of 6879 patients were included in the study. Two hundred and seventy-five patients (4.0%) presented with AAA, of which 16% were female and 84% were male. Patients with AAA were older than the (no AAA) control group (p < 0.0001). The following risk factors were identified for AAA: family history of AAA (p < 0.0001); history of vascular surgery (p < 0.0001), cerebrovascular accident (p < 0.0001), coronary heart disease (p < 0.0001), diabetes (p < 0.0001), medication (p = 0.0018), claudication (p < 0.0001), smoking history (p = 0.0001) and chronic obstructive pulmonary disorder (p = 0.0007). AAA is associated with classical vascular risk factors, in addition to other less-well-documented risk factors including previous vascular surgery. These findings have practical implications with the potential to improve future clinical screening of patients in order to reduce AAA mortality.

Acute global testicular infarction: A rare and important complication after endovascular abdominal aortic aneurysm repair.

Testicular ischemia is one of the most rarely reported complications of endovascular abdominal aortic aneurysm repair (EVAR). Although the pathogenesis remains unclear, thromboembolic events in the setting of testicular artery origin occlusion by the stent graft and poor baseline collateral testicular circulation are presumed causes. A 73-year-old man developed acute right testicular infarction 3 days after EVAR, requiring orchiectomy. This case emphasizes the importance of recognizing and evaluating testicular pain after EVAR and counseling patients on this possible EVAR complication.

Dual-Drug Nanomedicine Assembly with Synergistic Anti-Aneurysmal Effects via Inflammation Suppression and Extracellular Matrix Stabilization.

Abdominal aortic aneurysm (AAA) represents a critical cardiovascular condition characterized by localized dilation of the abdominal aorta, carrying a significant risk of rupture and mortality. Current treatment options are limited, necessitating novel therapeutic approaches. This study investigates the potential of a pioneering nanodrug delivery system, RAP@PFB, in mitigating AAA progression. RAP@PFB integrates pentagalloyl glucose (PGG) and rapamycin (RAP) within a metal-organic-framework (MOF) structure through a facile assembly process, ensuring remarkable drug loading capacity and colloidal stability. The synergistic effects of PGG, a polyphenolic antioxidant, and RAP, an mTOR inhibitor, collectively regulate key players in AAA pathogenesis, such as macrophages and smooth muscle cells (SMCs). In macrophages, RAP@PFB efficiently scavenges various free radicals, suppresses inflammation, and promotes M1-to-M2 phenotype repolarization. In SMCs, it inhibits apoptosis and calcification, thereby stabilizing the extracellular matrix and reducing the risk of AAA rupture. Administered intravenously, RAP@PFB exhibits effective accumulation at the AAA site, demonstrating robust efficacy in reducing AAA progression through multiple mechanisms. Moreover, RAP@PFB demonstrates favorable biosafety profiles, supporting its potential translation into clinical applications for AAA therapy.

Safety Evaluation of Unibody Endografts for Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-Analysis.

BACKGROUND: The unibody bifurcated aortic endograft (AFX/AFX2) has emerged as a treatment option for abdominal aortic aneurysms (AAAs). This systematic review and meta-analysis aimed to evaluate the safety of the unibody endograft. METHODS: A literature search was conducted in Cochrane Library, Scopus, Web of Science, and PubMed. Studies assessing the unibody endograft for abdominal aortic aneurysm repair between 2014 and 2023 were included. The defined primary outcomes were the incidences of type I, II, and III endoleaks. The secondary outcomes were access site problems, aneurysm-related mortality, aneurysm rupture, all-cause mortality, aneurysm sac growth, limb occlusion, stent graft migration, and technical success rate. RESULTS: 14 studies including 12 observational studies and two randomized controlled trials (RCTs) were included in the systematic review. The meta-analysis included 10 studies with 12,690 patients that reported the measured outcomes, and excluded four studies that did not. Type II endoleaks had the highest incidence of 12% (95% CI: 4-20%), followed by type III endoleaks with an incidence of 3% (95% CI: 1-5). The incidence of type I endoleaks was 1% (95% CI: 0-2%). A subgroup analysis by follow-up duration showed that type II endoleak incidence was higher after one to two years of follow-up than three to four years of follow-up. The incidence of aneurysmal mortality was 2% (95% CI: 0-7%); limb occlusion was 1% (95% CI: 0-1%); stent graft migration was 1% (95% CI: 0-2%); aneurysmal rupture was 6% (95% CI: 2-11%); access site problems were 7% (95% CI: 2-13%); aneurysm sac growth was 2% (95% CI: 0-4%);, all-cause mortality was 21% (95% CI: 4-38%), and technical success rate was 100% (95% CI: 98-100%). CONCLUSION: The unibody endograft is a safe and minimally invasive approach for AAA repair. However, potential complications necessitate close patient follow-up after the intervention.

Machine Learning Based Prediction of Post-operative Infrarenal Endograft Apposition for Abdominal Aortic Aneurysms.

OBJECTIVE: Challenging infrarenal aortic neck characteristics have been associated with increased risk of a type Ia endoleak after endovascular aneurysm repair (EVAR). Short apposition (< 10 mm circumferential shortest apposition length [SAL]) on the first post-operative computerised tomography angiography (CTA) has been associated with type Ia endoleak. Therefore, this study aimed to develop a model to predict post-operative SAL in patients with an abdominal aortic aneurysm based on the pre-operative shape. METHODS: A statistical shape model was developed to obtain principal component scores. The dataset comprised patients treated with standard EVAR without complications (n = 93) enriched with patients with a late type Ia endoleak (n = 54). The infrarenal SAL was obtained from the first post-operative CTA and subsequently binarised (< 10 mm and ≥ 10 mm). The principal component scores that were statistically different between the SAL groups were used as input for five classification models, and evaluated by means of leave one out cross validation. Area under the receiver operating characteristics curves (AUC), accuracy, sensitivity, and specificity were determined for each classification model. RESULTS: Of the 147 patients, 24 patients had an infrarenal SAL < 10 mm and 123 patients had a SAL ≥ 10 mm. The gradient boosting model resulted in the highest AUC of 0.77. Using this model, 114 (78.0%) patients were correctly classified; sensitivity (< 10 mm apposition was correctly predicted) and specificity (≥ 10 mm apposition was correctly predicted) were 0.70 and 0.79, and were based on a threshold of 0.21, respectively. CONCLUSION: A model was developed to predict which patients undergoing EVAR will achieve sufficient graft apposition (≥ 10 mm) in the infrarenal aortic neck based on a statistical shape model of pre-operative CTA data. This model can help vascular specialists during the planning phase to accurately identify patients who are unlikely to achieve sufficient apposition after standard EVAR.

Glutamine Protects against Mouse Abdominal Aortic Aneurysm through Modulating VSMC Apoptosis and M1 Macrophage Activation.

Glutamine (Gln), known as the most abundant free amino acid, is widely spread in human body. In this study, we demonstrated the protective effects of glutamine against mouse abdominal aortic aneurysm (AAA) induced by both angiotensin II (AngII) and calcium phosphate (Ca3(PO4)2) in vivo, which was characterized with lower incidence of mouse AAA. Moreover, histomorphological staining visually presented more intact elastic fiber and less collagen deposition in abdominal aortas of mice treated by glutamine. Further, we found glutamine inhibited the excessive production of reactive oxide species (ROS), activity of matrix metalloproteinase (MMP), M1 macrophage activation, and apoptosis of vascular smooth muscle cells (VSMCs) in suprarenal abdominal aortas of mice, what's more, the high expressions of MMP-2 protein, MMP-9 protein, pro-apoptotic proteins, and IL-6 as well as TNF-α in protein and mRNA levels in cells treated by AngII were down-regulated by glutamine. Collectively, these results revealed that glutamine protected against mouse AAA through inhibiting apoptosis of VSMCs, M1 macrophage activation, oxidative stress, and extracellular matrix degradation.

A protocolized five strategies in open repair for ruptured abdominal aortic aneurysm.

OBJECTIVES: Although the medical field has made significant progress, there has been little improvement in the survival rate of patients with ruptured abdominal aortic aneurysms (rAAAs). We implemented a protocol consisting of five strategies in the management of rAAA patients who underwent open repair surgery. METHODS: The protocol comprised the following strategies: intentional hypotension <70 mmHg, lung first and kidney last policy (restricted fluid resuscitation and permissive oligoanuria), immediate postoperative extubation, free-water intake with active ambulation, and open abdomen with the routine second-look operation. The study included 13 patients (11 male) with a mean age of 75.5 ± 7.4 (range: 58-87) years who underwent the procedure from 2016 to 2018, with a mean follow-up of 40.1 ± 9.04 months. Five deteriorating to hemodynamic shock and decreased consciousness requiring intubation and ventilation prior to surgery were observed. Two of these patients required preoperative cardiopulmonary resuscitation (CPR). RESULTS: All patients regained consciousness after surgery, including the two patients who required cardiopulmonary resuscitation. Immediate postoperative extubation was performed in nine patients, but two (22.2%) of them needed re-intubation due to ventilation/perfusion mismatch. Four patients underwent continuous renal replacement therapy, with three of them having anuria for up to 48 h after surgery. Two of these patients made a full recovery. Daily ambulation was carried out for a mean of 4.77 ± 3.5 (range 1-13) days with an open abdomen, during which no significant events were reported. Four cases of colon ischemia/necrosis were identified in the second-look operation, with two patients requiring Hartman's procedure and the other two undergoing left colon partial resection. There were two in-hospital mortalities (15.4%). CONCLUSIONS: A protocol-based approach, through multidisciplinary team consensus and the development of optimal surgical strategies, could improve clinical outcomes for patients undergoing emergency surgery for rAAA. Further studies with larger sample sizes are needed to refine the protocols.

Peri-operative Mortality and Morbidity of Complex Abdominal Aortic Aneurysms Repair in Switzerland: A Swissvasc Report.

OBJECTIVE: Complex abdominal aortic aneurysms (cAAA) pose a clinical challenge. The aim of this study was to assess the 30 day mortality and morbidity for open aneurysm repair (OAR) and fenestrated/branched endovascular aortic repair (F/BEVAR), and the effect of hospital volume in patients with asymptomatic cAAA in Switzerland. METHODS: Retrospective, cohort study using data from Switzerland's national registry for vascular surgery, Swissvasc, including patients treated from 1 January 2019 to 31 December 2022. All patients with asymptomatic, true, non-infected cAAA were identified. Primary outcome was 30 day mortality and morbidity reported using the Clavien-Dindo classification. Outcomes were compared between OAR and F/BEVAR after propensity score weighting. RESULTS: Of the 461 patients identified, 333 underwent OAR and 128 underwent F/BEVAR for cAAA. At 30 days, overall mortality rate was 3.3% after OAR and 3.1% after F/BEVAR (p = .76). Propensity scores weighted analysis indicated similar morbidity rates for both approaches: F/BEVAR (OR 0.69, 95% CI 0.45 - 1.05, p = .055); intestinal ischaemia (1.8% after OAR, 3.1% after F/BEVAR, p = .47) and renal failure requiring dialysis (1.5% after OAR, 5.5% after F/BEVAR, p = .024) were associated with highest morbidity and mortality. Treatment specific complications with high morbidity were abdominal compartment syndrome and lower limb compartment syndrome following F/BEVAR. Overall treatment volume was low for most of the hospitals treating cAAA in Switzerland; outliers with increased mortality were identified among low volume hospitals. CONCLUSION: Comparable 30 day mortality and morbidity rates were found between OAR and F/BEVAR for cAAA in Switzerland; lack of centralisation was also highlighted. Organ specific complications driving mortality were renal failure, intestinal ischaemia, and limb ischaemia, specifically after F/BEVAR. Treatment in specialised high volume centres, alongside efforts to reduce peri procedural kidney injury and mesenteric ischaemia, offers potential to lower morbidity and mortality in elective cAAA treatment.

Implantable Pressure-Sensing Devices for Monitoring Abdominal Aortic Aneurysms in Post-Endovascular Aneurysm Repair.

Over the past two decades, there has been extensive research into surveillance methods for the post-endovascular repair of abdominal aortic aneurysms, highlighting the importance of these technologies in supplementing or even replacing conventional image-screening modalities. This review aims to provide an overview of the current status of alternative surveillance solutions for endovascular aneurysm repair, while also identifying potential aneurysm features that could be used to develop novel monitoring technologies. It offers a comprehensive review of these recent clinical advances, comparing new and standard clinical practices. After introducing the clinical understanding of abdominal aortic aneurysms and exploring current treatment procedures, the paper discusses the current surveillance methods for endovascular repair, contrasting them with recent pressure-sensing technologies. The literature on three commercial pressure-sensing devices for post-endovascular repair surveillance is analyzed. Various pre-clinical and clinical studies assessing the safety and efficacy of these devices are reviewed, providing a comparative summary of their outcomes. The review of the results from pre-clinical and clinical studies suggests a consistent trend of decreased blood pressure in the excluded aneurysm sac post-repair. However, despite successful pressure readings from the aneurysm sac, no strong link has been established to translate these measurements into the presence or absence of endoleaks. Furthermore, the results do not allow for a conclusive determination of ongoing aneurysm sac growth. Consequently, a strong clinical need persists for monitoring endoleaks and aneurysm growth following endovascular repair.

Advances and challenges in regenerative therapies for abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a significant source of mortality worldwide and carries a mortality of greater than 80% after rupture. Despite extensive efforts to develop pharmacological treatments, there is currently no effective agent to prevent aneurysm growth and rupture. Current treatment paradigms only rely on the identification and surveillance of small aneurysms, prior to ultimate open surgical or endovascular repair. Recently, regenerative therapies have emerged as promising avenues to address the degenerative changes observed in AAA. This review briefly outlines current clinical management principles, characteristics, and pharmaceutical targets of AAA. Subsequently, a thorough discussion of regenerative approaches is provided. These include cellular approaches (vascular smooth muscle cells, endothelial cells, and mesenchymal stem cells) as well as the delivery of therapeutic molecules, gene therapies, and regenerative biomaterials. Lastly, additional barriers and considerations for clinical translation are provided. In conclusion, regenerative approaches hold significant promise for in situ reversal of tissue damages in AAA, necessitating sustained research and innovation to achieve successful and translatable therapies in a new era in AAA management.

Epigenetic modifications in abdominal aortic aneurysms: from basic to clinical.

Abdominal Aortic Aneurysm (AAA) is a disease characterized by localized dilation of the abdominal aorta, involving multiple factors in its occurrence and development, ultimately leading to vessel rupture and severe bleeding. AAA has a high mortality rate, and there is a lack of targeted therapeutic drugs. Epigenetic regulation plays a crucial role in AAA, and the treatment of AAA in the epigenetic field may involve a series of related genes and pathways. Abnormal expression of these genes may be a key factor in the occurrence of the disease and could potentially serve as promising therapeutic targets. Understanding the epigenetic regulation of AAA is of significant importance in revealing the mechanisms underlying the disease and identifying new therapeutic targets. This knowledge can contribute to offering AAA patients better clinical treatment options beyond surgery. This review systematically explores various aspects of epigenetic regulation in AAA, including DNA methylation, histone modification, non-coding RNA, and RNA modification. The analysis of the roles of these regulatory mechanisms, along with the identification of relevant genes and pathways associated with AAA, is discussed comprehensively. Additionally, a comprehensive discussion is provided on existing treatment strategies and prospects for epigenetics-based treatments, offering insights for future clinical interventions.

Unsupervised machine learning cluster analysis to identification EVAR patients clinical phenotypes based on radiomics.

OBJECTIVE: This study used unsupervised machine learning (UML) cluster analysis to explore clinical phenotypes of endovascular aortic repair (EVAR) for abdominal aortic aneurysm (AAA) patients based on radiomics. METHOD: We retrospectively reviewed 1785 patients with infra-renal AAA who underwent elective EVAR procedures between January 2010 and December 2020. Pyradiomics was used to extract the radiomics features. Statistical analysis was applied to determine the radiomics features that related to severe adverse events (SAEs) after EVAR. The selected features were used for UML cluster analysis in training set and validation in test set. Comparison of basic characteristics and radiomics features of different clusters. The Kaplan-Meier analysis was conducted to generate the cumulative incidence of freedom from SAEs rate. RESULT: A total of 1180 patients were enrolled. During the follow-up, 353 patients experienced EVAR-related SAEs. In total, 1223 radiomics features were extracted from each patient, of which 23 radiomics features were finally preserved to identify different clinical phenotypes. 944 patients were allocated to the training set. Three clusters were identified in training set, in which patients had identical clinical characteristics and morphological features, while varied considerably of selected radiomics features. This encouraging performance was further approved in the test set. In addition, each cluster was well differentiated from other clusters and Kaplan-Meier analysis showed significant differences of freedom from SAEs rate between different clusters both in the training (p = .0216) and test sets (p = .0253). CONCLUSION: Based on radiomics, UML cluster analysis can identify clinical phenotypes in EVAR patients with distinct long-term outcomes.

Correlation Between Calcium Scoring and Abdominal Aortic Aneurysm Endovascular Repair Outcomes.

OBJECTIVES: Endovascular aneurysm repair, though minimally invasive and has the benefit of relatively low perioperative complication rates, it is associated with significant long term reintervention rates related to endoleaks. Several variables have been studied to predict the outcomes of endovascular aneurysm repair, 1 of which is the calcium burden of the vasculature. This prompted us to study the association between calcium burden measured by the standardized Agatston scoring system and the outcomes of Endovascular aneurysm repair. METHODS: This is a retrospective study of patients who underwent Endovascular aneurysm repair from 2008 to 2020 at our institution and who had a non-contrast computerized tomography scan preoperatively, accounting for 87 patients. The calcium burden of the vasculature was measured by the Agatston scoring system allowing for better reproducibility, and the outcome variables included mortality and endoleaks. RESULTS: Patients with higher median total calcium scores (≥12966.9) had significantly lesser survival (79.8% vs 52.3% (P = .002) at five years compared to patients with lower median total calcium score (<12966.9). Also, patients with type 2 endoleaks had higher calcium scores in above the aneurysm level ((1591.2 vs 688.2), P = .05)) compared to patients with no type 2 endoleaks. CONCLUSION: Calcium score assigned using a standardized Agatston scoring system can be used as a predictor of mortality risk assisting in deciding the treatment of choice for patients.