Abdominal Aortic Aneurysms (Etiology, Epidemiology, and Natural History)

Impact of frailty on adverse outcomes in patients with abdominal aortic aneurysm undergoing surgery: a systematic review and meta-analysis

OBJECTIVE

To explore the prognostic role of frailty in patients with abdominal aortic aneurysm (AAA) by conducting this systematic review and meta-analysis METHODS: We conducted an extensive literature search on PubMed, Web of Sciences, and Embase databases to identify studies that reported the association of frailty with postoperative complications, reintervention, or all-cause mortality in patients with AAA after surgery. Short-term mortality was defined by a combination of in-hospital and 30-day death.

RESULTS

Seven cohort studies reporting on 9 articles with 323,788 AAA patients were included. The reported prevalence of frailty in AAA patients ranged between 2.3% and 34.6%. Pooling the results revealed that frailty was significantly associated with a higher risk of short-term all-cause mortality (adjusted risk ratios [RR] 3.20; 95% confidence intervals [CI] 1.95-5.26), long-term all-cause mortality (adjusted RR 2.86; 95% CI 2.57-3.17), and postoperative complications (adjusted RR 2.19; 95% CI 1.50-3.20) compared to non-frail individuals. However, there was no clear association between frailty and reintervention (HR 1.44; 95% CI 0.97-2.16).

CONCLUSIONS

Frailty independently predicts the short and long-term survival as well as postoperative complications in patients with AAA undergoing surgery. Assessing frail status may potentially enhance surgical decision-making for these patients.

Predicting feature genes correlated with immune infiltration in patients with abdominal aortic aneurysm based on machine learning algorithms

Abdominal aortic aneurysm (AAA) is a condition characterized by a pathological and progressive dilatation of the infrarenal abdominal aorta. The exploration of AAA feature genes is crucial for enhancing the prognosis of AAA patients. Microarray datasets of AAA were downloaded from the Gene Expression Omnibus database. A total of 43 upregulated differentially expressed genes (DEGs) and 32 downregulated DEGs were obtained. Function, pathway, disease, and gene set enrichment analyses were performed, in which enrichments were related to inflammation and immune response. AHR, APLNR, ITGA10 and NR2F6 were defined as feature genes via machine learning algorithms and a validation cohort, which indicated high diagnostic abilities by the receiver operating characteristic curves. The cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) method was used to quantify the proportions of immune infiltration in samples of AAA and normal tissues. We have predicted AHR, APLNR, ITGA10 and NR2F6 as feature genes of AAA. CD8 + T cells and M2 macrophages correlated with these genes may be involved in the development of AAA, which have the potential to be developed as risk predictors and immune interventions.

Status of diagnosis and therapy of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are characterized by localized dilation of the abdominal aorta. They are associated with several serious consequences, including compression of adjacent abdominal organs, pain, treatment-related financial expenditure. The main complication of AAA is aortic rupture, which is responsible for about 200,000 deaths per year worldwide. An increasing number of researchers are dedicating their efforts to study AAA, resulting in significant progress in this field. Despite the commendable progress made thus far, there remains a lack of established methods to effectively decelerate the dilation of aneurysms. Therefore, further studies are imperative to expand our understanding and enhance our knowledge concerning AAAs. Although numerous factors are known to be associated with the occurrence and progression of AAA, the exact pathway of development remains unclear. While asymptomatic at most times, AAA features a highly unpredictable disease course, which could culminate in the highly deadly rupture of the aneurysmal aorta. Current guidelines recommend watchful waiting and lifestyle adjustment for smaller, slow-growing aneurysms, while elective/prophylactic surgical repairs including open repair and endovascular aneurysm repair are recommended for larger aneurysms that have grown beyond certain thresholds (55 mm for males and 50 mm for females). The latter is a minimally invasive procedure and is widely believed to be suited for patients with a poor general condition. However, several concerns have recently been raised regarding the postoperative complications and possible loss of associated survival benefits on it. In this review, we aimed to highlight the current status of diagnosis and treatment of AAA by an in-depth analysis of the findings from literatures.

Sarcopenia defined by the psoas muscle mass or quality is associated with poor survival in patients with aortic aneurysm undergoing surgery: A meta-analysis

BACKGROUND

The impact of sarcopenia estimated by the skeletal muscle mass or quality on survival remains controversial in patients with aortic aneurysm. This meta-analysis aimed to assess the association between sarcopenia defined by the psoas muscle mass or quality and all-cause mortality in patients with aortic aneurysm.

METHODS

We comprehensively searched PubMed, Web of Science, and Embase databases until December 31, 2022. Studies investigating the association of CT-derived psoas muscle mass (psoas muscle area [PSA] and psoas muscle index [PMI]) or quality (lean PSA [LPSA]) with all-cause mortality in patients with aortic aneurysm undergoing surgery were included.

RESULTS

Eighteen studies reporting on 19 articles, enrolling 4767 patients were identified. A comparison of the bottom with the top psoas muscle mass, the pooled adjusted hazard ratios (HR) of all-cause mortality was 2.34 (95% confidence intervals [CI] 1.58-3.47). Low psoas muscle mass was associated with an increased risk of all-cause mortality when defined by the PSA (HR 2.01; 95% CI 1.42-2.75) or PMI (HR 2.37; 95% CI 1.24-4.55). Per 1 cm2 PMA increase conferred a 10% reduction in all-cause mortality. Patients with bottom LPMA had an increased risk of all-cause mortality (HR 3.27; 95% CI 1.90-5.60). Each 100 cm2 × HU LPMA increase conferred a 15% reduction in all-cause mortality.

CONCLUSIONS

Sarcopenia defined by the low psoas muscle mass or quality independently predicts all-cause mortality in patients with aortic aneurysm. However, the overall certainty of evidence for the categorical analysis of psoas muscle mass was downgraded by the presence of publication bias and significant heterogeneity.

Pharmacological Inhibition of Gasdermin D Suppresses Angiotensin II-Induced Experimental Abdominal Aortic Aneurysms

BACKGROUND

Gasdermin D, a molecule downstream of the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing inflammasome, forms the membrane pore for the secretion of interleukin (IL)-1β and IL-18, and also mediates pyroptosis. This study was to explore the influence of treatment with disulfiram, a small molecule inhibitor to gasdermin D, on the formation and progression of experimental abdominal aortic aneurysms (AAA).

METHODS

AAAs were induced in 10-week-old male apolipoprotein E deficient mice by subcutaneous infusion of angiotensin II (1000 ng/min/kg body weight) for 28 days via osmotic minipumps. Three days prior to angiotensin II infusion, disulfiram (50 mg/kg) or an equal volume of saline as the vehicle control was administered daily via oral gavage. The influence on experimental AAAs was analyzed by serial measurements of aortic diameters via ultrasonography, grading AAA severity and histopathology at sacrifice. Serum IL-1β and IL-18 levels, systolic blood pressure, total cholesterol, and triglyceride were also measured. Additional experiments assayed the influences on the cell viability and IL-1β secretion of in vitro activated macrophages.

RESULTS

Disulfiram significantly reduced the enlargement, incidence, and severity of angiotensin II-induced experimental AAAs with attenuation of medial elastin breaks, mural macrophage accumulation, and systolic blood pressure. The AAA suppression was also associated with reduced systemic levels of IL-1β but not IL-18. However, disulfiram treatment had no impact on body weight gain and lipid levels in aneurysmal mice. Additionally, disulfiram treatment also markedly reduced the secretion of IL-1β from activated macrophages with a limited effect on cell viability in vitro.

CONCLUSIONS

Gasdermin D inhibition by disulfiram attenuated angiotensin II-induced experimental AAAs with reduced systemic IL-1β levels and in vitro activated macrophage IL-1β secretion. Our study suggests that pharmacological gasdermin D inhibition may have translational potential for limiting clinical AAA progression.

Vascular Biology of arterial aneurysms

OBJECTIVE

This review aims to analyze biomolecular and cellular events responsible for arterial aneurysm formation with particular attention to vascular remodeling that determines the initiation and the progression of arterial aneurysm, till rupture.

METHODS

This review was conducted searching libraries such as Web of Science, Scopus, ScienceDirect and Medline. Used keywords with various combinations were: "arterial aneurysms", "biology", "genetics", "proteomics", "molecular", "pathophysiology" and extracellular matrix" RESULTS: There are several genetic alterations responsible of syndromic and non-syndromic disease that predispose to aneurysm formation. ECM imbalance, mainly due to the alteration of vascular smooth muscle cells (VSMCs) homeostasis, overexpression of metalloproteinases (MPs) and cytokines activation, determines weakness of the arterial wall that dilates thus causing aneurysmal disease. Altered mechanotransduction in the ECM may also trigger and sustain anomalous cellular and biochemical signaling. Different cell population such as VSMCs, macrophages, perivascular adipose tissue (PVAT) cells, vascular wall resident stem cells (VWRSCs) are all involved at different levels CONCLUSIONS: Improving knowledge in vascular biology may help researchers and physicians in better targeting aneurysmal disease in order to better prevent and better treat such important disease.