Aneurysm Formation Research Articles

Construction of Risk-Prediction Models for Autogenous Arteriovenous Fistula Thrombosis in Patients on Maintenance Hemodialysis

Introduction: Autogenous arteriovenous fistula (AVF) is the preferred vascular access in patients undergoing maintenance hemodialysis (MHD). However, complications such as thrombosis may occur. This study aimed to construct and validate a machine learning-based risk-prediction model for AVF thrombosis, hypothesizing that such a model can effectively predict occurrences, providing a foundation for early clinical intervention. Methods: The retrospective longitudinal study included a total of 270 patients who underwent MHD at the Hemodialysis Center of the Second Affiliated Hospital of Harbin Medical University between March 2021 and December 2022. During this study, baseline data and scale information of patients between March 2020 and December 2021 were collected. We recorded outcome indicators between March 2021 and December 2022 for subsequent analyses. Five machine learning models were developed (artificial neural network, logistic regression, ridge classification, random forest, and adaptive boosting). The sensitivity (recall), specificity, accuracy, and precision of each model were evaluated. The effect size of each variable was analyzed and ranked. Models were assessed using the area under the receiver-operating characteristic (AUROC) curve. Results: Among the 270 included patients, 105 had AVF thrombosis (55 male and 50 female patients; age range, 29–79 years; mean age, 56.72 years; standard deviation [SDs], ±13.10 years). Conversely, 165 patients did not have AVF thrombosis (99 male and 66 female patients; age range, 23–79 years; mean age, 53.58 years; SD, ± 13.33 years). During the observation period, approximately 52.6% of patients with AVF experienced long-term complications. The most common complications associated with AVF were thrombosis (105; 38.9%), aneurysm formation (27; 10%), and excessively high output flow (10; 3.7%). Fifty-four (20%) patients with AVF required intervention because of complications associated with vascular access. The AUROC curve of the testing set was between 0.858 and 0.903. Conclusion: In this study, we developed five machine learning models to predict the risk of AVF thrombosis, providing a reference for early clinical intervention.

Unleashing PD-1: a duel of immunity in aortic aneurysm formation.

Aortic aneurysms, particularly abdominal aortic aneurysms (AAAs), exhibit sex differences, with higher prevalence and severity in males than females, both in humans and experimental mouse models. In fact, male sex has been considered as the most potent nonmodifiable risk factor for AAA. Currently, there are no medications approved for the treatment of aortic aneurysms, despite the high lethality of ruptured aneurysms, which account for nearly 2% of all deaths. Moreover, the underlying molecular mechanisms mediating the sexual dimorphism of aortic aneurysms remain largely unknown. In this issue of the JCI, Mu et al. revealed a mechanism by which androgens, male sex hormones, exacerbate aortic aneurysms by suppressing programmed cell death protein 1 (PD-1) expression in T cells in an aldosterone and high salt-induced aortic aneurysm mouse model.

Loss of Smooth Muscle Tenascin-X Inhibits Vascular Remodeling Through Increased TGF-β Signaling.

Vascular smooth muscle cells (VSMCs) are highly plastic. Vessel injury induces a phenotypic transformation from differentiated to dedifferentiated VSMCs, which involves reduced expression of contractile proteins and increased production of extracellular matrix and inflammatory cytokines. This transition plays an important role in several cardiovascular diseases such as atherosclerosis, hypertension, and aortic aneurysm. TGF-β (transforming growth factor-β) is critical for VSMC differentiation and to counterbalance the effect of dedifferentiating factors. However, the mechanisms controlling TGF-β activity and VSMC phenotypic regulation under in vivo conditions are poorly understood. The extracellular matrix protein TN-X (tenascin-X) has recently been shown to bind TGF-β and to prevent it from activating its receptor. We studied the role of TN-X in VSMCs in various murine disease models using tamoxifen-inducible SMC-specific knockout and adeno-associated virus-mediated knockdown. In hypertensive and high-fat diet-fed mice, after carotid artery ligation as well as in human aneurysmal aortae, expression of Tnxb, the gene encoding TN-X, was increased in VSMCs. Mice with smooth muscle cell-specific loss of TN-X (SMC-Tnxb-KO) showed increased TGF-β signaling in VSMCs, as well as upregulated expression of VSMC differentiation marker genes during vascular remodeling compared with controls. SMC-specific TN-X deficiency decreased neointima formation after carotid artery ligation and reduced vessel wall thickening during Ang II (angiotensin II)-induced hypertension. SMC-Tnxb-KO mice lacking ApoE showed reduced atherosclerosis and Ang II-induced aneurysm formation under high-fat diet. Adeno-associated virus-mediated SMC-specific expression of short hairpin RNA against Tnxb showed similar beneficial effects. Treatment with an anti-TGF-β antibody or additional SMC-specific loss of the TGF-β receptor reverted the effects of SMC-specific TN-X deficiency. In summary, TN-X critically regulates VSMC plasticity during vascular injury by inhibiting TGF-β signaling. Our data indicate that inhibition of vascular smooth muscle TN-X may represent a strategy to prevent and treat pathological vascular remodeling.

Safety, effectiveness, and complications of the first-in-human minimally invasive transthoracic ventricular septal defect closure using a bioabsorbable occluder: a cohort study with 12-month follow-up.

Ventricular septal defect (VSD) is one of the most common congenital heart diseases. This study aims to evaluate the clinical value and benefit of transesophageal echocardiography (TEE) in transthoracic minimally invasive closure of VSDs using a completely biodegradable occluders, summarize the main points of surgical procedures, and analyze the follow-up results of short-term and medium-term treatment. We conducted a retrospective analysis of 24 pediatric cases of VSD, successfully treated with TEE-guided minimally invasive closure using fully biodegradable occluders between June 2019 and June 2022. The preoperative TEE meticulously examined the defect's location, size, and surrounding anatomical relationships, aiding in the selection of appropriate occluders and guiding the entire closure process. All patients were followed up for 1 year. In our cohort, 13 cases were perimembranous inlet VSDs, and 11 involved VSDs with membranous aneurysm formation. The effective shunt size of VSD measured by TEE preoperatively ranged from 2.8 to 4.9 mm, with the defect located 2-6 mm from the aortic valve. Occluders used were 6-8 mm in diameter. All 24 procedures were successful. TEE confirmed that the occluders were tightly fitted at the edges of the VSDs. Twenty-three cases had no residual shunt post-surgery, while one case exhibited a small left-to-right shunt (<1.5 mm) at the occluder's edge. Follow-up was conducted on postoperative day 3, and in months 1, 3, 6, and 12, showing that the occluder's position remained normal in all patients. Except for one child who had a 1.2 mm left-to-right shunt at the edge of the occluder, no residual shunts were observed in the others. The occluder started to degrade from month 6, and the sizes of the left and right occluder discs were significantly smaller compared to those on postoperative day 3 (P=0.003). TEE-guided minimally invasive VSD occlusion using fully biodegradable occluders has the advantages of minimal trauma, high safety, and few complications, with satisfactory recent efficacy, and good prospects for clinical safety applications.

Increased Expression of Mevalonate Pathway-Related Enzymes in Angiotensin II-Induced Abdominal Aortic Aneurysms.

Abdominal aortic aneurysm (AAA) is characterized by permanent luminal expansion and a high mortality rate due to aortic rupture. Despite the identification of abnormalities in the mevalonate pathway (MVA) in many diseases, including cardiovascular diseases, the potential impact of this pathway on AAA remains unclear. This study aims to investigate whether the expression of the MVA-related enzyme is altered during the progression of angiotensin II (Ang II) -induced AAA.Ang II 28D and Ang II 5D groups were continuously perfused with Ang II for 28 days and 5 days, respectively, and the Sham group was perfused with saline. The general and remodeling characteristics of AAA were determined by biochemical and histological analysis. Alteration of MVA-related enzyme expressions was revealed by western blot and single-cell RNA sequencing (scRNA-seq).The continuous Ang II infusion for 28 days showed significant aorta expansion and arterial remodeling. Although the arterial diameter slightly increased, the aneurysm formation was not found in Ang II induction for 5 days. MVA-related enzyme expression and activation of small GTP-binding proteins were significantly increased after Ang II-induced. As verified by scRNA-seq, the key enzyme gene expression was also higher in Ang II 28D. Similarly, it was detected that the expression levels of the above enzymes and the activity of small G proteins were elevated in the early stage of AAA as induced by Ang II infusion for 5 days.Continuous Ang II infusion-induced abdominal aortic expansion and arterial remodeling were accompanied by altered expression of key enzymes in the MVA.

Myeloid-Specific Thrombospondin-1 Deficiency Exacerbates Aortic Rupture via Broad Suppression of Extracellular Matrix Proteins.

Rupture of abdominal aortic aneurysms (AAA) is associated with high mortality. However, the precise molecular and cellular drivers of AAA rupture remain elusive. Our prior study showed that global and myeloid-specific deletion of matricellular protein thrombospondin-1 (TSP1) protects mice from aneurysm formation primarily by inhibiting vascular inflammation. To investigate the cellular and molecular mechanisms that drive AAA rupture by testing how TSP1 deficiency in different cell populations affects the rupture event. We deleted TSP1 in endothelial cells and macrophages --- the major TSP1-expressing cells in aneurysmal tissues ---- by crossbreeding Thbs1 flox/flox mice with VE-cadherin Cre and Lyz2-cre mice, respectively. Aortic aneurysm and rupture were induced by angiotensin II in mice with hypercholesterolemia. Myeloid-specific Thbs1 knockout, but not endothelial-specific knockout, increased the rate of lethal aortic rupture by more than 2 folds. Combined analyses of single-cell RNA sequencing and histology showed a unique cellular and molecular signature of the rupture-prone aorta that was characterized by a broad suppression in inflammation and extracellular matrix production. Visium spatial transcriptomic analysis on human AAA tissues showed a correlation between low TSP1 expression and aortic dissection. TSP1 expression by myeloid cells negatively regulates aneurysm rupture, likely through promoting the matrix repair phenotypes of vascular smooth muscle cells thereby increasing the strength of the vascular wall.

Systematic review and meta-analysis of current evidences in endograft therapy vs. medical treatment for Spontaneous Isolated Superior Mesenteric Artery Dissection.

Endovascular stent therapy (EST) for spontaneous isolated superior mesenteric artery dissection (SISMAD) is gaining popularity, yet the treatment strategy - BMT or EST - remains debatable. A meta-analysis examined all randomized trials and observational studies exploring the relative merits and potential risks of EST vs. BMT in treating SISMAD patients. Key outcomes included early and long-term adverse effects, with odds ratios (ORs) and 95% confidence intervals (CI) calculated. A random- or fixed-effects model was selected according to a 50% heterogeneity threshold. 9 observational studies involving a total of 672 SISMAD patients (303 EST), met our selection criteria. We discovered no noteworthy distinctions between the EST group and the BMT group in terms of early symptoms' alleviation, reinterventions, or all-cause mortality. However, patients receiving EST management will be hospitalized longer than those receiving BMT (EST: 13.2 ± 5.1 months vs. BMT: 7.0 ± 2.2 months, P < 0.01). In the long run, EST was found to significantly contribute to a higher rate of complete remodeling (OR: 4.53, CI: 3.01 ~ 6.81, P < 0.01; heterogeneity, I2 = 50%) and a lower incidence of aneurysm formation (OR: 0.19, CI: 0.06 ~ 0.6, P < 0.01; heterogeneity, I2 = 0%) than BMT. However, there are no significant differences between ESTand BMTin terms of all-cause mortality, recurrent syndrome, reintervention, and SMA stenosis or occlusion. EST can effectively prevent the formation of aneurysmal dissection and improve SISMAD remodeling. Both EST and BMT are similar in reducing long-term mortality, recurrent symptoms, severe SMA stenosis or occlusion, and the need for reintervention in patients with SISMAD.

T Cells Immune Imbalance Present in Patients With Multiple Intracranial Aneurysms.

Growing evidence suggests that systemic immune and inflammatory responses may play a critical role in the formation and development of aneurysms. Exploring the differences between single intracranial aneurysm (SIA) and multiple IAs (MIAs) could provide insights for targeted therapies. However, there is a lack of comprehensive and detailed characterization of changes in circulating immune cells in MIAs. Peripheral blood mononuclear cell (PBMC) samples from patients with SIA (n = 16) or MIAs (n = 6) were analyzed using high-dimensional mass cytometry to evaluate the frequency and phenotype of immune cell subtypes. A total of 25 cell clusters were identified, revealing that the immune signature of MIAs included cluster changes. Compared to patients with SIA, patients with MIAs exhibited immune dysfunction and regulatory imbalance in T-cell clusters. They also had reduced numbers of CD8+ T cells and their subgroups CD8+ Te and CD8+ Tem cells, as well as reduced numbers of the CD4+ T-cell subgroup CD27-CD4+ Tem cells. Furthermore, compared to SIA, MIAs were associated with enhanced T-cell immune activation, with elevated expression levels of CD3, CD25, CD27, CCR7, GP130, and interleukin 10. This study provides insights into the circulating immune cell profiles in patients with MIAs, highlighting the similarities and differences between patients with SIA and those with MIAs. Furthermore, the study suggests that circulating immune dysfunction may contribute to development of MIAs.

L-Wnk1 Deletion in Smooth Muscle Cells Causes Aortitis and Inflammatory Shift.

The long isoform of the Wnk1 (with-no-lysine [K] kinase 1) is a ubiquitous serine/threonine kinase, but its role in vascular smooth muscle cells (VSMCs) pathophysiology remains unknown. AngII (angiotensin II) was infused in Apoe-/- to induce experimental aortic aneurysm. Mice carrying an Sm22-Cre allele were cross-bred with mice carrying a floxed Wnk1 allele to specifically investigate the functional role of Wnk1 in VSMCs. Single-cell RNA-sequencing of the aneurysmal abdominal aorta from AngII-infused Apoe-/- mice revealed that VSMCs that did not express Wnk1 showed lower expression of contractile phenotype markers and increased inflammatory activity. Interestingly, WNK1 gene expression in VSMCs was decreased in human abdominal aortic aneurysm. Wnk1-deficient VSMCs lost their contractile function and exhibited a proinflammatory phenotype, characterized by the production of matrix metalloproteases, as well as cytokines and chemokines, which contributed to local accumulation of inflammatory macrophages, Ly6Chi monocytes, and γδ T cells. Sm22Cre+Wnk1lox/lox mice spontaneously developed aortitis in the infrarenal abdominal aorta, which extended to the thoracic area over time without any negative effect on long-term survival. AngII infusion in Sm22Cre+Wnk1lox/lox mice aggravated the aortic disease, with the formation of lethal abdominal aortic aneurysms. Pharmacological blockade of γδ T-cell recruitment using neutralizing anti-CXCL9 (anti-CXC motif chemokine ligand 9) antibody treatment, or of monocyte/macrophage using Ki20227, a selective inhibitor of CSF1 receptor, attenuated aortitis. Wnk1 deletion in VSMCs led to aortic wall remodeling with destruction of elastin layers, increased collagen content, and enhanced local TGF-β (transforming growth factor-beta) 1 expression. Finally, in vivo TGF-β blockade using neutralizing anti-TGF-β antibody promoted saccular aneurysm formation and aorta rupture in Sm22 Cre+ Wnk1lox/lox mice but not in control animals. Wnk1 is a key regulator of VSMC function. Wnk1 deletion promotes VSMC phenotype switch toward a pathogenic proinflammatory phenotype, orchestrating deleterious vascular remodeling and spontaneous severe aortitis in mice.

Predicting Aneurysmal Degeneration in Uncomplicated Residual Type B Aortic Dissection.

The formation of an aneurysm in the false lumen (FL) is a long-term complication in a significant percentage of type B aortic dissection (AD) patients. The ability to predict which patients are likely to progress to aneurysm formation is key to justifying the risks of interventional therapy. The investigation of patient-specific hemodynamics has the potential to enable a patient-tailored approach to improve prognosis by guiding disease management for type B dissection. CFD-derived hemodynamic descriptors and geometric features were used to retrospectively assess individual aortas for a population of residual type B AD patients and analyze correlations with known outcomes (i.e., rapid aortic growth, death). The results highlight great variability in flow patterns and hemodynamic descriptors. A rapid aortic expansion was found to be associated with a larger FL. Time-averaged wall shear stress at the tear region emerged as a possible indicator of the dynamics of flow exchange between lumens and its effect on the evolution of individual aortas. High FL flow rate and tortuosity were associated with adverse outcomes suggesting a role as indicators of risk. AD induces complex changes in vessel geometry and hemodynamics. The reported findings emphasize the need for a patient-tailored approach when evaluating uncomplicated type B AD patients and show the potential of CFD-derived hemodynamics to complement anatomical assessment and help disease management.

Vertebrobasilar system variations; Analysis with multi-detector CT angiography

Objective: The vertebrobasilar system provides vascular nutrition to the posterior part of the brain, medulla spinalis, medulla oblongata, and cerebellum. Anatomical variations in these vascular structures increase the incidence of thrombus and aneurysms in patients. This study examines the presence of anatomical anomalies in the vertebrobasilar system. Material and Methods: Retrospective CT angiogram images of 93 adult cases over 18 years of age who were examined for any reason in KSU, Training and Research Hospital Radiology Unit. Results: Vertebral artery hypoplasia was observed in 15% of the cases. Left dominance was observed in 64.2% of the cases, right dominance in 28.6%, and co-dominance in 7.2%. Vertebral artery duplication was not observed. Vertebral artery fenestration was observed in 2.1% of cases. Vertebral artery of flexible origin was detected in 7.5%. In 57% of cases with a variable origin, the vertebral artery originated as the second branch of the subclavian artery. The right vertebral artery originating from the brachiocephalic artery was seen in 14.2%, the left vertebral artery originating from the arcus aorta was seen in 14.2%, and the left aberrant vertebral artery was seen in 14.2%. Fenestration of the basilar artery was observed in 2.1%, and hypoplasia of the basilar artery in 1.1%. Fetal type PCA variation was observed in 35.4% of cases, bilateral fetal PCA in 3.2%, right fetal PCA in 17.2%, and left fetal PCA in 15%. PCA duplication was observed in 3.2%, SCA duplication in 16.1%, unpaired single SCA in 2.1%, and SCA fenestration in 1.1%. An unpaired single AICA was observed in 15%, duplication of AICA in 2.1%, hypoplastic AICA in 6.4%, and AICA originating from SCA in 1.1%. An unpaired single PICA was observed in 12.9%, hypoplastic PICA in 2.1%, basilar artery originating PICA in 9.6%, AICA originating PICA in 4.3%, and PICA duplication in 1.1%. Conclusion: This study provides a detailed analysis of anatomical variations in the vertebrobasilar system using multi-detector CT angiography. The findings highlight the prevalence and diversity of these variations, such as vertebral artery hypoplasia, dominance patterns, fenestrations, and origin variations. These variations have significant clinical implications, particularly in the context of interventional and surgical procedures, as well as in the diagnosis and management of cerebrovascular diseases. Recognizing and understanding these anatomical differences can aid clinicians in planning more effective treatment strategies, potentially reducing the risk of complications associated with thrombus and aneurysm formation. Further research with larger and more diverse populations is recommended to validate these findings and to explore the impact of these variations on clinical outcomes. Ultimately, this study contributes to the existing body of knowledge and underscores the importance of personalized approaches in the management of vertebrobasilar system anomalies.

Exploratory analysis of predictors of ventricular aneurysm in a cohort of 291 patients with acute myocardial infarction

ObjectiveIn this study, we explored the determinants of ventricular aneurysm development following acute myocardial infarction (AMI), thereby prompting timely interventions to enhance patient prognosis.MethodsIn this retrospective cohort analysis, we evaluated 297 AMI patients admitted to the First People’s Hospital of Changzhou. The study was structured as follows. Comprehensive baseline data collection included hematological evaluations, ECG, echocardiography, and coronary angiography upon admission. Within 3 months post-AMI, cardiac ultrasounds were administered to detect ventricular aneurysm development. Univariate and multivariate logistic regression analysis were employed to pinpoint the determinants of ventricular aneurysm formation. Subsequently, a predictive model was formulated for ventricular aneurysm post-AMI. Moreover, the diagnostic efficacy of this model was appraised using the ROC curves.ResultsIn our analysis of 291 AMI patients, spanning an age range of 32–91 years, 247 were male (84.9%). At the conclusion of a 3-month observational period, the cohort bifurcated into two subsets: 278 patients without ventricular aneurysm and 13 with evident ventricular aneurysm. Distinguishing features of the ventricular aneurysm subgroup were markedly higher values for age, B-type natriuretic peptide(BNP), Left atrium(LA), Left ventricular end-diastolic dimension (LEVDD), left ventricular end systolic diameter (LVEWD), E-wave velocity (E), Left atrial volume (LAV), E/A ratio (E/A), E/e ratio (E/e), ECG with elevated adjacent four leads(4 ST-Elevation), and anterior wall myocardial infarction(AWMI) compared to their counterparts (p < 0.05). Among the singular predictive factors, total cholesterol (TC) emerged as the most significant predictor for ventricular aneurysm development, exhibiting an AUC of 0.704. However, upon crafting a multifactorial model that incorporated gender, TC, an elevated ST-segment in adjacent four leads, and anterior wall infarction, its diagnostic capability: notably surpassed that of the standalone TC, yielding an AUC of 0.883 (z = -9.405, p = 0.000) as opposed to 0.704. Multivariate predictive model included gender, total cholesterol, ST elevation in 4 adjacent leads, anterior myocardial infarction, the multivariate predictive model showed better diagnostic efficacy than single factor index TC (AUC: 0. 883 vs. 0.704,z =-9.405, p = 0.000), it also improved predictive power for correctly reclassifying ventricular aneurysm occurrence in patients with AMI, NRI = 28.42% (95% CI: 6.29-50.55%; p = 0.012). Decision curve analysis showed that the use of combination model had a positive net benefit.ConclusionLipid combined with ECG model after myocardial infarction could be used to predict the formation of ventricular aneurysm and aimed to optimize and adjust treatment strategies.

Site-specific genetic and functional signatures of aortic endothelial cells at aneurysm predilection sites in healthy and AngIIApoE-/- mice.

Aortic aneurysm is characterized by a pathological dilation at specific predilection sites of the vessel and potentially results in life-threatening vascular rupture. Herein, we established a modified "Häutchen method" for the local isolation of endothelial cells (ECs) from mouse aorta to analyze their spatial heterogeneity and potential role in site-specific disease development. When we compared ECs from aneurysm predilection sites of healthy mice with adjacent control segments we found regulation of genes related to extracellular matrix remodeling, angiogenesis and inflammation, all pathways playing a critical role in aneurysm development. We also detected enhanced cortical stiffness of the endothelium at these sites. Gene expression of ECs from aneurysms of the AngIIApoE-/- model when compared to sham animals mimicked expression patterns from predilection sites of healthy animals. Thus, this work highlights a striking genetic and functional regional heterogeneity in aortic ECs of healthy mice, which defines the location of aortic aneurysm formation in disease.

Smooth muscle cell phenotypic switching occurs independent of aortic dilation in bicuspid aortic valve-associated ascending aortas.

Bicuspid aortic valves (BAV) are frequently associated with ascending aortic aneurysms. The etiology is incompletely understood, but genetic factors, in addition to flow perturbations, are likely involved. Since loss of contractility and elaboration of extracellular matrix in the vessel wall are features of BAV-associated aortopathy, phenotypic modulation of smooth muscle cells (SMCs) may play a role. Ascending aortic tissue was collected intra-operatively from 25 individuals with normal (i.e., tricuspid) aortic valves (TAV) and from 25 individuals with BAVs. For both TAV and BAV, 10 patients had non-dilated (ND) and 15 patients had dilated (D) aortas. SMCs were isolated and cultured from a subset of patients from each group. Aortic tissue and SMCs were fluorescently immunolabeled for SMC phenotypic markers (i.e., alpha-smooth muscle actin (ASMA, contractile), vimentin (synthetic) and p16INK4a and p21Cip1 (senescence). SMCs were also analyzed for replicative senescence in culture. In normal-sized and dilated BAV aortas, SMCs switched from the contractile state to either synthetic or senescent phenotypes, as observed by loss of ASMA (ND: P = 0.001, D: P = 0.002) and associated increases in vimentin (ND: P = 0.03, D: P = 0.004) or p16/p21 (ND: P = 0.03, D: P<0.0001) compared to TAV. Dilatation of the aorta exacerbated SMC phenotypic switching in both BAV and TAV aortas (all P<0.05). In SMCs cultured from normal and dilated aortas, those isolated from BAV reached replicative senescence faster than those from TAV aortas (all P = 0.02). Furthermore, there was a stark inverse correlation between ASMA and cell passage number in BAV SMCs (ND: P = 0.0006, D: P = 0.01), but not in TAV SMCs (ND: P = 0.93, D: P = 0.20). The findings of this study provide direct evidence from cell culture studies implying that SMCs switch from the contractile state to either synthetic or senescent phenotypes in the non-dilated BAV aorta. In cultured SMCs from both non-dilated and dilated aortas, we found that this process may precede dilatation and accompany aneurysm development in BAV. Our findings suggest that therapeutically targeting SMC phenotypic modulation in BAV patients may be a viable option to prevent or delay ascending aortic aneurysm formation.

A Case of Arterial Thoracic Outlet Syndrome Thrombus Extending to Juxtavertebral Artery

Arterial thoracic outlet syndrome (TOS) constitutes less than 1%, involving the second part of the subclavian artery (SCA). It can present as an acute upper limb ischemia or aneurysm formation. Here is a case of a 29-year-old male presented with complaints of rest pain over the left hand for the past 2 weeks. Upon evalution, found to have bilateral cervical rib with left subclavian artery occlusion. Treated by cervical rib excision decompression of scalene triangle, subclavian endarterectomy and left brachial embolectomy. Arterial TOS secondary to the cervical rib is rare; pathology involving this external compression results in repeated trauma in the intima of the SCA, resulting in subclavian stenosis, poststenotic dilatation, thrombosis, and aneurysm formation with mural thrombus and distal embolization. Symptomatic cases need decompression +/- arterial repair.

Roles and Mechanisms of miRNAs in Abdominal Aortic Aneurysm: Signaling Pathways and Clinical Insights.

Abdominal aortic aneurysm refers to a serious medical condition that can cause the irreversible expansion of the abdominal aorta, which can lead to ruptures that are associated with up to 80% mortality. Currently, surgical and interventional procedures are the only treatment options available for treating abdominal aortic aneurysm patients. In this review, we focus on the upstream and downstream molecules of the microRNA-related signaling pathways and discuss the roles, mechanisms, and targets of microRNAs in abdominal aortic aneurysm modulation to provide novel insights for precise and targeted drug therapy for the vast number of abdominal aortic aneurysm patients. Recent studies have highlighted that microRNAs, which are emerging as novel regulators of gene expression, are involved in the biological activities of regulating abdominal aortic aneurysms. Accumulating studies suggested that microRNAs modulate abdominal aortic aneurysm development through various signaling pathways that are yet to be comprehensively summarized. A total of six signaling pathways (NF-κB signaling pathway, PI3K/AKT signaling pathway, MAPK signaling pathway, TGF-β signaling pathway, Wnt signaling pathway, and P53/P21 signaling pathway), and a total of 19 miRNAs are intimately associated with the biological properties of abdominal aortic aneurysm through targeting various essential molecules. MicroRNAs modulate the formation, progression, and rupture of abdominal aortic aneurysm by regulating smooth muscle cell proliferation and phenotype change, vascular inflammation and endothelium function, and extracellular matrix remodeling. Because of the broad crosstalk among signaling pathways, a comprehensive analysis of miRNA-mediated signaling pathways is necessary to construct a well-rounded upstream and downstream regulatory network for future basic and clinical research of AAA therapy.

Novel Insights into the Aortic Mechanical Properties of Mice Modeling Hereditary Aortic Diseases.

Hereditary aortic diseases (hADs) increase the risk of aortic dissections and ruptures. Recently, we have established an objective approach to measure the rupture force of the murine aorta, thereby explaining the outcomes of clinical studies and assessing the added value of approved drugs in vascular Ehlers-Danlos syndrome (vEDS). Here, we applied our approach to six additional mouse hAD models. We used two mouse models (Fbn1C1041G and Fbn1mgR ) of Marfan syndrome (MFS) as well as one smooth-muscle-cell-specific knockout (SMKO) of Efemp2 and three CRISPR/Cas9-engineered knock-in models (Ltbp1, Mfap4, and Timp1). One of the two MFS models was subjected to 4-week-long losartan treatment. Per mouse, three rings of the thoracic aorta were prepared, mounted on a tissue puller, and uniaxially stretched until rupture. The aortic rupture force of the SMKO and both MFS models was significantly lower compared with wild-type mice but in both MFS models higher than in mice modeling vEDS. In contrast, the Ltbp1, Mfap4, and Timp1 knock-in models presented no impaired aortic integrity. As expected, losartan treatment reduced aneurysm formation but surprisingly had no impact on the aortic rupture force of our MFS mice. Our read-out system can characterize the aortic biomechanical integrity of mice modeling not only vEDS but also related hADs, allowing the aortic-rupture-force-focused comparison of mouse models. Furthermore, aneurysm progression alone may not be a sufficient read-out for aortic rupture, as antihypertensive drugs reducing aortic dilatation might not strengthen the weakened aortic wall. Our results may enable identification of improved medical therapies of hADs.

Acute Limb Ischemia Secondary to Thrombosis in Persistent Sciatic Artery: A Case Report and Review of Management Strategies

Persistent sciatic artery (PSA) is a rare vascular anomaly with potential for significant vascular complications. We present a case of a 39-year-old male with acute limb ischemia secondary to thrombosis in a PSA, highlighting the challenges in diagnosis and management. Despite the absence of aneurysmal formation, the patient presented with severe pain and absent distal pulses, prompting urgent intervention. Computed tomography angiography revealed thrombosis extending into the left common iliac artery. Catheter-directed thrombolysis (CDT) was successfully performed, resulting in complete resolution of the thrombus and restoration of limb perfusion. The patient experienced symptomatic relief postoperatively and regained ambulatory function. This case underscores the importance of considering PSA in the differential diagnosis of acute limb ischemia and highlights CDT as an effective treatment modality. Further research is needed to optimize the management of acute limb ischemia associated with PSA and to evaluate long-term outcomes.

Focal aneurysm formation in a coronary bypass graft after permanent pacemaker implantation

Focal aneurysm formation in a coronary bypass graft after permanent pacemaker implantation

Is TEVAR an Effective Approach to Prevent Complications after Surgery for Aortic Dissection Type A? A Systematic Review.

Introduction: A residual false lumen after treatment for Aortic Dissection type A (AD) has been associated with early complications, such as A malperfusion or rupture and mid-term or delayed complications, such as aneurysm formation or dissection expansion. Thoracic Endovascular Aortic Repair (TEVAR) is considered an effective solution by several surgical teams to prevent future complications. In this systematic review, all published data regarding the implementation of TEVAR after previous treatment for AD were collected in order to investigate indications, methods, clinical outcomes and aortic remodeling in these patients. Methods: The aim of this study was to investigate the indications, the methods and the efficacy of TEVAR usage after surgical treatment of AD. Data for this study were collected from four widely used medical databases (MEDLINE, SCIENCE DIRECT, GOOGLE SCHOLAR, OVID). All the results for each database were recorded and were analyzed with a systematic method. Techniques and clinical outcomes were investigated. Aortic remodeling was evaluated based on the following parameters in these studies: aortic diameter, true lumen diameter, false lumen diameter, false lumen thrombosis and false lumen patency. Results: The results obtained from the search among all databases comprised 1410 articles and of these articles 9 were included in the review. The majority of the studies were retrospective (seven out of nine studies), while no study was randomized. The total number of patients was 157 and 133 of them (84.7% of patients) were treated with TEVAR in zone 3 without extension below the diaphragm intraoperatively. Among 142 patients, the calculated mortality rate was 12.7% (18 of 142 patients), with 2.8% (4 of 142 patients) presenting with stroke. The percentage of patients with total or partial thrombosis combined was 65.9% (62 patients in a population of 92). The reintervention rate was 18.7%. Conclusions: TEVAR after AD surgery is an approach usually chosen in clinical practice, but the criteria of its usage are uncertain. This method is safe and enhances aortic remodeling with an acceptable reintervention rate. Definite guidelines in this field should be created in order to delineate whether TEVAR after AD surgery is beneficial as a preventive measure to aorta-related complications and to decide under which criteria this approach should be chosen.