Systematic review and meta-analysis of the prevalence of abdominal aortic aneurysm in Asian populations

How to improve epidemiological trustworthiness concerning abdominal aortic aneurysms

BACKGROUND

Research on degenerative abdominal aortic aneurysms (AAA) is hampered by complex pathophysiology, sub-optimal pre-clinical models, and lack of effective medical therapies. In addition, trustworthiness of existing epidemiological data is impaired by elements of ambiguity, inaccuracy, and inconsistency. Our aim is to foster debate concerning the trustworthiness of AAA epidemiological data and to discuss potential solutions.

METHODS

We searched the literature from the last five decades for relevant epidemiological data concerning AAA development, rupture, and repair. We then discussed the main issues burdening existing AAA epidemiological figures and proposed suggestions potentially beneficial to AAA diagnosis, prognostication, and management.

RESULTS

Recent data suggest a heterogeneous scenario concerning AAA epidemiology with rates markedly varying by country and study cohorts. Overall, AAA prevalence seems to be decreasing worldwide while mortality is apparently increasing regardless of recent improvements in aortic-repair techniques. Prevalence and mortality are decreasing in high-income countries, whereas low-income countries show an increase in both. However, several pieces of information are missing or outdated, thus systematic renewal is necessary. Current AAA definition and surgical criteria do not consider inter-individual variability of baseline aortic size, further decreasing their reliability.

CONCLUSIONS

Switching from flat aortic-size thresholds to relative aortic indices would improve epidemiological trustworthiness regarding AAAs. Aortometry standardization focusing on simplicity, univocity, and accuracy is crucial. A patient-tailored approach integrating clinical data, multi-adjusted indices, and imaging parameters is desirable. Several novel imaging modalities boast promising profiles for investigating the aortic wall. New contrast agents, computational analyses, and artificial intelligence-powered software could provide further improvements.

Cost-Effectiveness analysis of endovascular versus open repair in patients with abdominal aortic aneurysm in Iran: A Cross-Sectional study

OBJECTIVES

Abdominal aortic aneurysm is one of the most important cardiovascular diseases, especially in the elderly. People with this disease are at risk of rupture of the abdominal aorta and death. The present study was conducted with the aim of analyzing the cost effectiveness of endovascular repair compared to open surgery in abdominal aortic aneurysm patients in Iran.

METHODS

A Markov chain model was developed based on the use of endovascular repair and open surgery. The base-case patient was defined as a 65-year-old man presenting with abdominal aortic aneurysm diameter greater than 5 cm. The determination of costs was from the perspective of the public sector provider. QALY was used to calculate the effectiveness. Incremental cost-effectiveness ratio (ICER) and TreeAge software were used for cost-effectiveness analysis. The follow-up period was 10 years and the willingness to pay (WTP) was determined as three times the Gross domestic product (GDP) per capita.

RESULT

At the end of year 10, the endovascular aneurysm repair (EVAR) strategy gained 1,318,313,559 Iranian Rial (IRR) (67885.29$) in cost and 3.57 QALYs in effectiveness. In contrast, the use of the open surgery repair (OSR) strategy gained 1,186,761,858 IRR (61111.16$) in cost and 3·32 QALYs in effectiveness. The incremental cost-effectiveness ratio, comparing EVAR versus OSR, was 53, 346, 3757 IRR (178.36$) per QALYs, which is lower than the proposed WTP, indicating that EVAR is more expensive and more effective. Based on the Monte Carlo simulation test, EVAR is the preferred strategy in 58.6% of the population.

CONCLUSION

Endovascular repair has a relative superiority compared to open surgery, and the probability of the effectiveness of endovascular repair compared to open surgery does not change with increasing willingness to pay.

The future for the therapeutics of abdominal aortic aneurysm: engineered nanoparticles drug delivery for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease with a high mortality rate. Several screening and diagnostic methods have been developed for AAA early diagnosis. Open surgery and endovascular aortic repair (EVAR) are clinically available for patients who meet the indications for surgery. However, for non-surgical patients, limited drugs exist to inhibit or reverse the progression of aneurysms due to the complex pathogenesis and biological structure of AAA, failing to accumulate precisely on the lesion to achieve sufficient concentrations. The recently developed nanotechnology offers a new strategy to address this problem by developing drug-carrying nanoparticles with enhanced water solubility and targeting capacity, prolonged duration, and reduced side effects. Despite the rising popularity, limited literature is available to highlight the progression of the field. Herein, in this review, we first discuss the pathogenesis of AAA, the methods of diagnosis and treatment that have been applied clinically, followed by the review of research progressions of constructing different drug-loaded nanoparticles for AAA treatment using engineered nanoparticles. In addition, the feasibility of extracellular vesicles (EVs) and EVs-based nanotechnology for AAA treatment in recent years are highlighted, together with the future perspective. We hope this review will provide a clear picture for the scientists and clinicians to find a new solution for AAA clinical management.

Incidental Cardiovascular Abnormalities in the Abdominal Aortic Aneurysm (AAA) Surveillance Population During the AAA Get Fit Trial: A Case Series and Review of the Literature

Background The prevalence of cardiovascular disease and incidence of major adverse cardiovascular events (MACEs) is very high among the abdominal aortic aneurysm (AAA) surveillance population. Formal assessments of and interventions to reduce cardiovascular risk are not a routine part of the surveillance programme at present. However, its potential importance is highlighted by incidental findings during the AAA Get Fit Trial, a randomised controlled trial which included baseline cardiopulmonary exercise testing (CPET). We speculate that CPET can act as an opportunistic screening programme to identify cardiovascular disease in AAA surveillance patients. Methods The AAA Get Fit Trial was a prospective, randomised controlled trial at a tertiary vascular centre, Manchester University NHS Foundation Trust, conducted between November 2017 and August 2019. Patients underwent CPET at baseline, 8, 16, 24 and 36 weeks as well as clinical history and examination and blood tests. We report on incidental cardiovascular abnormalities diagnosed during the trial. Results Of the 59 participants in the trial, four (6.8%) were identified to have abnormal findings suggestive of unstable cardiovascular disease. On subsequent further investigation, two patients were diagnosed and treated for severe coronary artery disease after abnormal ECG findings were noted during CPET. One patient was diagnosed with unstable angina after obtaining a detailed history on baseline assessment which was treated medically before going on to have a successful elective AAA repair. Conclusions There is a high incidence of MACEs among this high-risk population both pre and perioperatively. Identifying and treating cardiovascular disease among the AAA surveillance population must be a focus of the future AAA screening programme.

Myeloid-derived suppressor cells promote the formation of abdominal aortic aneurysms through the IL-3-ICOSL-ICOS axis

Th17 cells are powerful inflammation promoters in the pathogenesis of abdominal aortic aneurysms (AAAs). Myeloid-derived suppressor cells (MDSCs) can promote the differentiation of Th17 cells in chronic inflammatory autoimmune injury. Here, we aim to examine whether MDSCs regulate the differentiation of Th17 cells to participate in the development of AAA. We demonstrated an abnormal accumulation of MDSCs in AAA patients, which was positively associated with Th17 cells. We established angiotensin II-induced apolipoprotein E knockout mice and found the impaired immunosuppressive function of M-MDSCs. After systemic injection of anti-Gr-1 antibody in AAA mice to deplete circulating MDSCs, AAA formation and the differentiation of Th17 cells were abolished, and the overexpression of inducible T-cell costimulator (ICOS) on Th17 cells was reversed accordingly. Regulating the expression of ICOS ligand (ICOSL) on MDSCs affects the differentiation of Th17 cells. The adoptive transfer of ICOSLlowMDSCs in AAA mice inhibited the differentiation of Th17 cells and the development of AAA. Meanwhile, rIL-3 promoted the survival and immunosuppressive dysfunction of MDSCs, upregulated ICOSL expression on MDSCs by inhibiting activation of the PI3K/AKT signaling pathway, and regulated MDSCs to promote the differentiation of Th17 cells via the ICOSL-ICOS axis. An increase in serum IL-3, ICOSL+MDSCs, and ICOS+Th17 cells was detected in AAA patients, and IL-3 levels were positively correlated with the proportion of ICOSL+MDSC cells. In conclusion, we uncovered a pivotal role of MDSCs in promoting the differentiation of Th17 cells through the IL-3-ICOSL-ICOS axis during AAA, providing an important theoretical basis for understanding the pathogenesis of AAA.

MiR-125b and SATB1-AS1 might be shear stress-mediated therapeutic targets

The aim of the study was to explore the potential molecular mechanism associated with shear stress on abdominal aortic aneurysm (AAA) progression. This study performed RNA sequencing on AAA patients (SQ), AAA patients after endovascular aneurysm repair (EVAR, SH), and normal controls (NC). Furthermore, we identified the differentially expressed microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNA (cirRNAs) and constructed competing endogenous RNA (ceRNA) networks. Finally, 164 differentially expressed miRNAs, 179 co-differentially expressed lncRNAs, and 440 co-differentially expressed circRNAs among the three groups were obtained. The differentially expressed miRNAs mainly enriched in 325 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Target genes associated with co-differentially expressed genes among the group of SH, SQ, and NC mainly enriched in 66 KEGG pathways. LncRNA-miRNA-mRNA interactions, including 15 lncRNAs, 63 miRNAs and 57 mRNAs, was constructed. CircRNA-miRNA-mRNA ceRNA network included 79 circRNAs, 21 miRNAs, and 49 mRNAs. Among them, KLRC2 and CSTF1, targeted by miR-125b, participated in cell-mediated immunity regulation. MiR-320-related circRNAs and SATB1-AS1 serving as the sponge of miRNAs, such as has-circ-0129245, has-circ-0138746, and has-circ-0139786, were hub genes in ceRNA network. In conclusion, AAA patients might be benefit from EVAR based on various pathways and some molecules, such as miR-125b and SATB1-AS1, related with shear stress.

Totally percutaneous versus surgical cut-down femoral artery access for elective bifurcated abdominal endovascular aneurysm repair

BACKGROUND

Abdominal aortic aneurysms (AAAs) are a vascular condition with significant risk attached, particularly if they rupture. Therefore, it is critical to identify and repair these as an elective procedure before they rupture and require emergency surgery. Repair has traditionally been an open surgical technique that required a large incision across the abdomen. Endovascular abdominal aortic aneurysm repairs (EVARs) are now a common alternative. In this procedure, the common femoral artery is exposed via a cut-down approach and a graft is introduced to the aneurysm in this way. This Cochrane Review examines a totally percutaneous approach to EVAR. This technique gives a minimally invasive approach to femoral artery access that may reduce groin wound complication rates and improve recovery time. However, the technique may be less applicable in people with, for example, groin scarring or arterial calcification. This is an update of the previous Cochrane Review published in 2017.

OBJECTIVES

To evaluate the benefits and harms of totally percutaneous access compared to cut-down femoral artery access in people undergoing elective bifurcated abdominal endovascular aneurysm repair (EVAR).

SEARCH METHODS

We used standard, extensive Cochrane search methods The latest search was 8 April 2022.

SELECTION CRITERIA

We included randomised controlled trials in people diagnosed with an AAA comparing totally percutaneous versus surgical cut-down access endovascular repair. We considered all device types. We only considered studies investigating elective repairs. We excluded studies reporting emergency surgery for ruptured AAAs and those reporting aorto-uni-iliac repairs.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. short-term mortality, 2. failure of aneurysm exclusion and 3. wound infection. Secondary outcomes were 4. major complications (30-day or in-hospital); 5. medium- to long-term (6 and 12 months) complications and mortality; 6. bleeding complications and haematoma; and 7. operating time, duration of intensive treatment unit (ITU) stay and hospital stay. We used GRADE to assess the certainty of evidence for the seven most clinically relevant primary and secondary outcomes.

MAIN RESULTS

Three studies with 318 participants met the inclusion criteria, 189 undergoing the percutaneous technique and 129 treated by cut-down femoral artery access. One study had a small sample size and did not adequately report the method of randomisation, allocation concealment or preselected outcomes. The other two larger studies had few sources of bias and good methodology; although one study had a high risk of bias in selective reporting. We observed no clear difference in short-term mortality between groups, with only one death occurring overall, in the totally percutaneous group (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.06 to 36.18; 2 studies, 181 participants; low-certainty evidence). One study reported failure of aneurysm exclusion. There was one failure of aneurysm exclusion in the surgical cut-down femoral artery access group (RR 0.17, 95% CI 0.01 to 4.02; 1 study, 151 participants; moderate-certainty evidence). For wound infection, there was no clear difference between groups (RR 0.18, 95% CI 0.01 to 3.59; 3 studies, 318 participants; moderate-certainty evidence). There was no clear difference between percutaneous and cut-down femoral artery access groups in major complications (RR 1.21, 95% CI 0.61 to 2.41; 3 studies, 318 participants; moderate-certainty evidence), bleeding complications (RR 1.02, 95% CI 0.29 to 3.64; 2 studies, 181 participants; moderate-certainty evidence) or haematoma (RR 0.88, 95% CI 0.13 to 6.05; 2 studies, 288 participants). One study reported medium- to long-term complications at six months, with no clear differences between the percutaneous and cut-down femoral artery access groups (RR 0.82, 95% CI 0.25 to 2.65; 1 study, 135 participants; moderate-certainty evidence). We detected differences in operating time, with the percutaneous approach being faster than cut-down femoral artery access (mean difference (MD) -21.13 minutes, 95% CI -41.74 to -0.53 minutes; 3 studies, 318 participants; low-certainty evidence). One study reported the duration of ITU stay and hospital stay, with no clear difference between groups.

AUTHORS' CONCLUSIONS

Skin puncture may make little to no difference to short-term mortality. There is probably little or no difference in failure of aneurysm exclusion (failure to seal the aneurysms), wound infection, major complications within 30 days or while in hospital, medium- to long-term (six months) complications and bleeding complications between the two groups. Compared with exposing the femoral artery, skin puncture may reduce the operating time slightly. We downgraded the certainty of the evidence to moderate and low as a result of imprecision due to the small number of participants, low event rates and wide CIs, and inconsistency due to clinical heterogeneity. As the number of included studies was limited, further research into this technique would be beneficial.

Social Vulnerability And Outcomes For Access-Sensitive Surgical Conditions Among Medicare Beneficiaries

Concerns have been raised over wide variation in rates of unplanned (emergency or urgent) surgery for access-sensitive surgical conditions-diagnoses requiring surgery that preferably is planned (elective) but, when access is limited, may be delayed until worsening symptoms require riskier and costlier unplanned surgery. Yet little is known about geographic and community-level factors that may increase the likelihood of unplanned surgery with adverse outcomes. We examined the relationship between community-level social vulnerability and rates of unplanned surgery for three access-sensitive conditions in 2014-18 among fee-for-service Medicare beneficiaries ages 65-99. Compared with patients from communities with the lowest social vulnerability, those from communities with the highest vulnerability were more likely, overall, to undergo unplanned surgery (36.2 percent versus 33.5 percent). They were also more likely to experience worse outcomes largely attributable to differential rates of unplanned surgery, including higher rates of mortality (5.4 percent versus 5.0 percent) and additional surgery within thirty days (19.6 percent versus 18.1 percent). Our findings suggest that policy addressing community-level social vulnerability may mitigate the observed differences in surgical procedures and outcomes for access-sensitive conditions.

Systematic Reviews of the Literature Are Not Always Either Useful Or the Best Way To Add To Science

Systematic reviews are becoming more popular as a way of doing research; however, not all systematic reviews are clinically useful and sometimes another type of review (scoping, topical, or critical) would be of greater value to the clinical and scientific community. The different types of review and their use are described, illustrated by examples relevant to vascular surgery.

Importance of NLRP3 Inflammasome in Abdominal Aortic Aneurysms

Abdominal aortic aneurysm (AAA) is a chronic inflammatory degenerative aortic disease, which particularly affects older people. Nucleotide-binding oligomerization domain-like receptor family protein 3 (NLRP3) inflammasome is a multi-protein complex and mediates inflammatory responses by activating caspase 1 for processing premature interleukin (IL)-1β and IL-18. In this review, we first summarize the principle of NLRP3 inflammasome activation and the functionally distinct classes of small molecule NLRP3 inflammasome inhibitors. Next, we provide a comprehensive literature review on the expression of NLRP3 inflammasome effector mediators (IL-1β and IL-18) and components (caspase 1, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and NLRP3) in clinical and experimental AAAs. Finally, we discuss the influence of genetic deficiency or pharmacological inhibition of individual effector mediators and components of NLRP3 inflammasome on experimental AAAs. Accumulating clinical and experimental evidence suggests that NLRP3 inflammasome may be a promise therapeutic target for developing pharmacological strategies for clinical AAA management.