The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm

Use of ultra-low contrast dose CT aortography for the management of aortic aneurysmal disease

PURPOSE

Computed tomography aortography (CTA) is used in the assessment of aortic pathologies and planning of surgical intervention. However, its dependence on iodinated contrast can result in development of contrast-induced acute kidney injury (CI-AKI). The potential concern of CI-AKI has spurred research into the potential of administration of low contrast volumes in CTA investigations while maintaining overall diagnostic appeal. Several studies have shown that CTA using contrast volumes as low as 30 mL (equivalent to 10.5 g of iodine) can still yield scans of diagnostic quality. We present a retrospective pilot study to evaluate the feasibility of utilising an ultra-low volume of iodinated intravenous contrast in a population of patients with severe renal insufficiency with referral from our vascular surgery unit for CTA evaluation of the thoracic and abdominal aorta.

METHODS

This retrospective pilot study examined 12 CTA scans performed with 20 mLs of iodinated contrast and assessed image quality with both quantitative and qualitative markers. All scans were performed on a Siemens SOMATOM Force dual-source CT scanner. Quantitative assessment values were measured via attenuation values at eight aortoiliac locations and used to calculate a signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) at each location. Qualitative analysis of image quality and viability for surgical intervention was obtained from subjective clinical assessment by an interventional radiologist and vascular surgeon.

RESULTS

Obtained quantitative assessment values included mean attenuation 189.9 HU, mean SNR 9.6 and mean CNR 8.0. All 12 scans demonstrated individual mean SNR values above predetermined quality thresholds while only five scans produced individual mean CNR values above threshold. Eleven of 12 scans were determined to be of sufficient quality for diagnosis and planning of surgical intervention.

CONCLUSIONS

Our results suggest that CTA utilising an ultra-low contrast dose of 20 mLs (6 g iodine) yields scans of diagnostic quality for therapeutic decision-making in vascular surgical intervention.

Monocentric Evaluation of Physician-Modified Fenestrations or Parallel Endografts for Complex Aortic Diseases

PURPOSE

This study aimed to investigate the demographic and anatomic characteristics, as well as perioperative and follow-up results of fenestration and parallel techniques for the endovascular repair of complex aortic diseases.

MATERIALS AND METHODS

A retrospective study was conducted on 67 consecutive patients underwent endovascular treatment for complex aortic diseases including abdominal aortic aneurysm (AAA), thoracoabdominal aneurysm (TAAA), aortic dissection, or prior endovascular repair with either fenestrated and parallel endovascular aortic repair (f-EVAR or ch-EVAR) at a single institute from 2013 to 2021. Choices of intervention were made by the disease' emergency, patients' general condition, the anatomic characteristics, as well as following the recommendation from the devices' guidelines. Patients' clinical demographics, aortic disease characteristics, perioperative details, and disease courses were discussed. Short- and mid-term follow-up results were obtained and analyzed. Endpoints were aneurysm-related and unrelated mortality, branch instability, and renal function deterioration.

RESULTS

Totally, 34 and 27 patients received f-EVAR and ch-EVAR, while 6 patients received a combination of both. Fenestrated endovascular aortic repair was conducted mainly in AAA affecting visceral branches and TAAA, whereas ch-EVAR was normally utilized for infrarenal AAA. Regarding the average number of reconstructed arteries per patient, there was a significant difference among f-EVAR, ch-EVAR, and the combination group (mean = 2.3 ± 0.9, 1.4 ± 0.6, 3.5 ± 0.5, p<0.001). Primary technical success was achieved in 28 (82.4%), 22 (81.5%), and 3 (50.0%) patients for each group. Besides operational time (5.77 ± 2.58, 4.47 ± 1.44, p=0.033), no significant difference was observed for blood transfusion, intensive care unit (ICU) or hospital stay, blood creatinine level, 30-day complications, or follow-up complications between patients undergoing f-EVAR or ch-EVAR. Patients receiving combination of both techniques had a higher rate of blood transfusion (p=0.044), longer operational time (p=0.008) or hospital stay (p=0.017), as well as more stent occlusion (p=0.001), endoleak (p=0.004) at short-term and a higher rate of endoleak (p=0.023) at mid-term follow-up.

CONCLUSION

In conclusion, this study demonstrated that f-EVAR and ch-EVAR techniques had acceptable perioperative and follow-up results and should be considered viable alternatives when encountering complex aortic diseases.

CLINICAL IMPACT

This study sought to investigate the baseline and pathological characteristics, as well as perioperative and follow-up results of f-EVAR and ch-EVAR at a single Chinese institution. F-EVAR (mostly physician-modified f-EVAR) was applied in patients with a wide range of etiologies and disease types, while ch-EVAR was preferred for AAA in older patients with an average higher ASA grade. Our experience suggested acceptable safety and efficacy both for techniques, and no significant difference was observed between the two groups regarding any short or mid-term adverse events.

The Effect of One Year Aneurysm Sac Dynamics on Five Year Mortality and Continued Aneurysm Sac Evolution

OBJECTIVE

One year aneurysm sac dynamics after endovascular abdominal aortic aneurysm repair (EVAR) were independently associated with a greater all cause mortality risk in prior registry studies but were limited in completeness and granularity. This retrospective analysis aimed to study the impact of sac dynamics on survival within the Endurant Stent Graft Global Registry (ENGAGE) with five year follow up.

METHODS

A total of 1 263 subjects were enrolled in the ENGAGE Registry between March 2009 and April 2011. One year aneurysm sac changes were calculated between the one month post-operative imaging scans and the scan closest to the time of one year follow up. Sac regression was defined as a sac decrease of ≥ 5 mm and sac expansion as aneurysm sac growth ≥ 5 mm. The primary outcome was the five year all cause mortality rate. Kaplan-Meier estimates for freedom from all cause death were calculated. Multivariable Cox regression was used to determine the association between sac dynamics and all cause death.

RESULTS

At one year, 441 of the 949 study participants with appropriate imaging (46%) had abdominal aortic aneurysm sac regression, 462 (49%) remained stable, and 46 (4.8%) had sac expansion. For patients with sac regression, the five year all cause mortality rate was 20%, compared with 28% for stable sac (p = .007) and 37% for the sac expansion (p = .010) cohorts. After adjustment, the sac expansion and stable sac cohorts were associated with a greater all cause mortality rate (expansion: hazard ratio [HR] 1.8; 95% CI 1.1 - 3.2; p = .032; stable: HR 1.4; 95% CI 1.1 - 1.9; p = .019).

CONCLUSION

In the ENGAGE Global Registry, the one year rate of sac regression was 46%, and one year sac regression was observed to be associated with greater five year survival, corroborating prior findings using data from vascular registries. Sac regression could become the new standard for success after EVAR.

Geographical disparities in access to surgical treatment and mortality rates from abdominal aortic aneurysms in Brazil: A retrospective longitudinal study

INTRODUCTION

Abdominal aortic aneurysm (AAA) is a growing public health problem, and not all patients have access to surgery when needed. This study aimed to analyze spatiotemporal variations in AAA mortality and surgical procedures in Brazilian intermediate geographic regions and explore the impact of different surgical techniques on operative mortality.

METHODS

A retrospective longitudinal study was conducted to evaluate AAA mortality from 2008 to 2020 using space-time cube (STC) analysis and the emerging hot spot analysis tool through the Getis-Ord Gi* method.

RESULTS

There were 34,255 deaths due to AAA, 13,075 surgeries to repair AAA, and a surgical mortality of 14.92%. STC analysis revealed an increase in AAA mortality rates (trend statistic = +1.7693, p = 0.0769) and a significant reduction in AAA surgery rates (trend statistic = -3.8436, p = 0.0001). Analysis of emerging hotspots revealed high AAA mortality rates in the South, Southeast, and Central-West, with a reduction in procedures in São Paulo and Minas Gerais States (Southeast). In the Northeast, there were extensive areas of increasing mortality rates and decreasing procedure rates (cold spots).

CONCLUSION

AAA mortality increased in several regions of the country while surgery rates decreased, demonstrating the need for implementing public health policies to increase the availability of surgical procedures, particularly in less developed regions with limited access to services.

Fibrin Glue Sac Filling for Preventing Type II Endoleak, Short-Term Outcomes of a Prospective Randomized Controlled Trial

OBJECTIVE

Type II endoleak (T2EL) worsens the long-term results of endovascular aneurysm repair (EVAR). How to prevent T2ELs remains controversial. This study aimed to evaluate the efficacy and safety of fibrin glue sac filling (FGSF) to prevent T2ELs after EVAR.

METHODS

A prospective randomized controlled trial was conducted. Patients were randomly divided into group A (standard EVAR + FGSF) and group B (standard EVAR). The follow-up plans included outpatient or telephone consultation at 1 and 3 months and computed tomography (CT) angiography at 6 months, 1 year, and once a year after EVAR.

RESULTS

A total of 64 abdominal aortic aneurysm (AAA) patients were randomized to the 2 groups. All patients were followed up for more than 6 months. The 2 groups showed similar baseline characteristics. The rate of T2ELs on immediate angiography in group A (9.6%) was significantly lower than that in group B (33.3%, p=0.033). Moreover, the sac area change was significantly reduced in group A at 6 months after EVAR (p=0.021). However, T2EL incidence was similar at the 6-month (p=0.055) and 1-year (p=0.057) follow-ups, and AAA diameter change was also similar at 1 year. There were similar operation times, radiation doses, severe adverse events (SAEs), and reinterventions between the 2 groups.

CONCLUSION

Fibrin glue sac filling could prevent short-term type II endoleaks and promote AAA shrinkage after 6 months. The FGSF procedure is swift and straightforward; however, patients are at risk of bowel ischemia, especially after previous bowel resections or concomitant superior mesenteric artery (SMA) disease.

CLINICAL IMPACT

Standard endovascular aneurysm repair (EVAR) couldn't prevent type II endoleak (T2EL). In this study, we found fibrin glue sac filling (FGSF) could prevent T2EL and promote AAA shrinkage in a short term. And the FGSF procedure is easy, it will be a useful supplement to standard EVAR for clinicians. And FGSF might have potential usefulness on ruptured aneurysms, although without direct evidence.Fibrin glue is often used to hemostasis and tissue adhesion in surgical patients and burn patients, we firstly carry out a randomized controlled study and prove that fibrin glue sac filling could prevent T2EL and promote sac remodeling.

Psoas muscle analysis as a surrogate marker of sarcopenia and frailty: A multicenter analysis of predictive capacities over short- and long-term outcomes after abdominal aortic aneurysm repair

OBJECTIVES

Several predictive models exist for estimating the postoperative risks of abdominal aortic aneurysm (AAA) repair, although no particular tool has seen widespread use. We present the results of a multicenter, historic cohort study comparing the predictive capacity of the psoas muscle area (PMA), radiodensity (PMD), and lean muscle area (LMA) as surrogate markers of sarcopenia, over short- and long-term outcomes after AAA repair, compared to the mFI-5 and American Society of Anesthesiologists (ASA) scales.

METHODS

Retrospective review was conducted of all consecutive AAA elective repair cases (open or endovascular) in three tertiary-care centers from 2014 to 2019. Cross-sectional PMA, PMD, and LMA at the mid-body of the L3 vertebra were measured by two independent operators in the preoperative computed tomography. Receiver operating characteristic (ROC) curves were used to determine optimal cutoff values. Bivariate analysis, logistic regression, and Cox's proportional hazards models were built to examine the relationship between baseline variables and postoperative mortality, long-term mortality, and complications.

RESULTS

596 patients were included (mean age 72.7 ± 8 years, 95.1% male, 66.9% EVAR). Perioperative mortality was 2.3% (EVAR 1.2% vs open repair 4.6%, p = .015), and no independent predictors could be identified in the multivariate analysis. Conversely, an age over 74 years old (OR 1.84 95%CI 1.25-2.70), previous heart diseases (OR 1.62 95%CI 1.13-2.32), diabetes mellitus (OR 1.61 95%CI 1.13-2.32), and a PMD value over 66 HU (OR 0.58 95%CI 0.39-0.84) acted as independent predictors of long-term mortality in the Cox's proportional hazards model. Heart diseases (congestive heart failure or coronary artery disease), serum creatinine levels over 1.05 mg/dL, and an aneurysm diameter over 60 mm were independent predictors of major complications.

CONCLUSION

Surrogate markers of sarcopenia had a poor predictive profile for postoperative mortality after AAA repair in our sample. However, PMD stood out as an independent predictor of long-term mortality. This finding can guide future research and should be confirmed in larger datasets.

Glucagon-Like Peptide-1 Inhibits the Progression of Abdominal Aortic Aneurysm in Mice: The Earlier, the Better

OBJECTIVES

Glucagon-like peptide-1 (GLP-1) has a cardiovascular protective effect by preventing abdominal aortic aneurysm (AAA) formation. However, it is unclear at what point the agent should be administered to achieve the optimal effect. In this study, we aimed to determine whether administering the GLP-1 receptor agonist liraglutide during the earlier stages would more efficiently inhibit AAA progression in mice.

METHODS

Depending on the group, mice were given a daily dose of 300 μg/kg liraglutide for 28 days at 7, 14, and 28 days after aneurysm induction. The morphology of the abdominal aorta was monitored using 7.0 T magnetic resonance imaging (MRI) during the administration of liraglutide. After 28 days of administration, the AAA dilatation ratio was calculated, and histopathological examination was performed. Oxidative stress levels were evaluated by the expression of malondialdehyde (MDA) and matrix metalloproteinases (MMPs). The inflammatory response was also evaluated.

RESULTS

Liraglutide treatment led to a decrease in AAA formation, including a reduction in abdominal aorta expansion, elastin degradation in the elastic laminae, and vascular inflammation caused by leukocyte infiltration. The expression of MDA and the activity of MMPs (MMP-2, MMP-9) also decreased. Notably, administering liraglutide during the early stages resulted in a significant reduction in the dilatation rate of the aortic wall, as well as in MDA expression, leukocyte infiltration, and MMP activity in the vascular wall.

CONCLUSIONS

The GLP-1 receptor agonist liraglutide was found to inhibit AAA progression in mice by exerting anti-inflammatory and antioxidant effects, particularly during the early stages of AAA formation. Therefore, liraglutide may represent a potential pharmacological target for the treatment of AAA.

Evaluating the feasibility of contrast-enhanced ultrasound for detecting after preemptive coiling endoleaks in endovascular aortic aneurysm repair: A pilot study

Endovascular aortic aneurysm repair is widely used for the treatment of abdominal aortic aneurysm (AAA), but has a 10% to 40% incidence of type II endoleak during follow-up. There are various techniques to treat these endoleaks in the case of enlarging of the AAA, but the clinical effectiveness is low. In recent years, preemptive AAA sac embolization has shown some encouraging results with significant AAA shrinkage. However, the presence of embolic material can complicate continued endoleak detection making assessment of treatment outcome difficult. We investigate the ability of contrast-enhanced-ultrasound examination to detect endoleaks in patients undergoing preemptive coil embolization of the AAA sac.

Endoplasmic reticulum stress in abdominal aortic aneurysm

Abdominal aortic aneurysms (AAAs) are characterized by permanent dilatation of the abdominal aorta, which is accompanied by inflammation, degradation of the extracellular matrix (ECM) and disruption of vascular smooth muscle cell (VSMC) homeostasis. Endoplasmic reticulum (ER) stress is involved in the regulation of inflammation, oxidative stress and VSMC apoptosis, all of which are critical factors in AAA development. Although several studies have revealed the occurrence of ER stress in AAA development, the specific biological functions of ER stress in AAA development remain largely unknown. Given that targeting ER stress is a promising strategy for treating AAAs, further investigation of the physiological and pathological roles of ER stress in AAA development is warranted.

A patient-centered textbook outcome measure effectively discriminates contemporary elective open abdominal aortic aneurysm repair quality

BACKGROUND

There is persistent controversy surrounding the merit of surgical volume benchmarks being used solely as a sufficient proxy for assessing the quality of open abdominal aortic aneurysm (AAA) repair. Importantly, operative volume quotas may fail to reflect a more nuanced and comprehensive depiction of surgical outcomes most relevant to patients. Accordingly, we herein propose a patient-centered textbook outcome (TO) for AAA repair that is analogous to other large magnitude extirpative operations performed in other surgical specialties, and test its feasibility to discriminate hospital performance using Society for Vascular Surgery (SVS) volume guidelines.

METHODS

All elective open infrarenal AAA repairs (OAR) in the SVS-Vascular Quality Initiative were examined (2009-2022). The primary end point was a TO, defined as a composite of no in-hospital complication or reintervention/reoperation, length of stay of ≤10 days, home discharge, and 1-year survival rates. The discriminatory ability of the TO measure was assessed by comparing centers that did or did not meet the SVS annual OAR volume threshold recommendation (high volume ≥10 OARs/year; low volume <10 OARs/year). Logistic regression and multivariable models adjusted for patient and procedure-related differences.

RESULTS

A total of 9657 OARs across 198 centers were analyzed (mean age, 69.5 ± 8.4 years; female, 26%; non-White, 12%). A TO was identified in 44% (n = 4293) of the overall cohort. The incidence of individual TO components included no in-hospital complication (61%), no in-hospital reintervention or reoperation (92%), length of stay of ≤10 days (78%), home discharge (76%), and 1-year survival (91%). Median annual center volume was 6 (interquartile range, 3-10) and a majority of centers did not meet the SVS volume suggested threshold (<10 OARs/year, n = 148 [74%]). However, most patients (6265 of 9657 [65%]) underwent OAR in high-volume hospitals. When comparing high- and low-volume centers, a TO was more likely to occur in high-volume institutions: ≥10 OARs/year (46%) vs <10 OARs/year (42%; P = .0006). The association of a protective effect for higher center volume remained after risk adjustment (odds ratio, 1.1; 95% confidence interval, 1.05-1.26; P = .003).

CONCLUSIONS

TOs for elective OAR reflect a more nuanced and comprehensive patient centered proxy to measure care delivery, consistent with other surgical specialties. Surprisingly, a TO was achieved in <50% of elective AAA cases nationally. Although the likelihood of a TO seems to correlate with SVS center volume recommendations, it more importantly reflects elements which may be prioritized by patients and thus offers insights into further improving real-world AAA care.

Carbon dioxide cone-beam computed tomography for the technical assessment of endovascular aortic intervention

Cone-beam computed tomography (CBCT) is widely used for the technical assessment of standard and complex endovascular aortic interventions. Use of iodinated contrast in CBCT imaging might provide useful additional information; however, this also increases the procedural contrast dose, which may cause renal function deterioration, and the radiation exposure. We describe the technique and feasibility of carbon-dioxide (CO2)-enhanced CBCT for the technical assessment of standard and complex endovascular aortic repair. In our experience CO2-CBCT had no related adverse events and provided satisfactory imaging quality to assess endograft integrity, vessels patency, and was safely performed in case of severe chronic renal insufficiency.

Malnutrition is associated with adverse 30-day outcomes after endovascular repair of abdominal aortic aneurysm

BACKGROUND

Malnutrition is particularly pertinent in patients undergoing vascular surgery, who frequently present with a high burden of comorbidities and advanced age that can impede nutrient absorption. While previous studies have established that vascular surgery patients with malnutrition had poorer outcomes, the impact of nutritional status in patients undergoing endovascular aneurysm repair (EVAR) has not yet been investigated. Therefore, this study aimed to assess the effect of malnutrition on 30-day outcomes following non-ruptured EVAR.

METHODS

Patients who had infrarenal EVAR were identified in the ACS-NSQIP targeted database from 2012-2022. Exclusion criteria included age less than 18 years, ruptured aneurysm, and emergency. Malnutrition was defined as patients with preoperative weight loss of greater than 10% decrease in body weight in the 6 months immediately preceding the surgery. A 1:5 propensity-score matching was used to match demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, anesthesia, and concomitant procedures between patients with and without malnutrition. Thirty-day postoperative outcomes were examined.

RESULTS

There were 154 (0.94%) patients with malnutrition who went under non-ruptured EVAR. Meanwhile, 16,309 patients without malnutrition went under intact EVAR, where 737 of them were matched to all malnutrition patients. Malnourished patients had more comorbidity burdens. After propensity-score matching, patients with malnutrition had elevated but non-significant 30-day mortality (5.92% vs 2.99%, p = .09). However, malnutrition patients had higher risks of renal complications (2.63% vs 0.68%, p = .04), bleeding requiring transfusion (22.37% vs 14.38%, p = .02), and unplanned reoperation (11.18% vs 4.88%, p = .01), as well as longer length of stay (6.11 ± 7.91 vs 4.44 ± 6.22 days, p < .02).

CONCLUSION

Patients with malnutrition experienced higher rates of morbidity after non-ruptured EVAR. Targeting malnutrition could be a strategy for preventing complications after EVAR and proper preoperative malnutritional management could be warranted.

Impaired Pre-operative Ambulatory Capacity in Patients Undergoing Elective Endovascular Infrarenal Abdominal Aortic Aneurysm Repair is Associated with Increased Peri-operative Death

OBJECTIVE

While ambulatory capacity is a readily assessable clinical indicator of functional status, its association with outcomes after endovascular aneurysm repair (EVAR) remains underexplored. This study aimed to investigate the association between pre-operative ambulatory status and outcomes following elective EVAR.

METHODS

A retrospective review of the multi-institutional Vascular Quality Initiative database was conducted for all patients who underwent elective infrarenal EVAR from 2009 - 2022. Patients were categorised into independent ambulation and impaired ambulation groups. A propensity score matched analysis was performed to produce two well matched cohorts in a 1:1 ratio without replacement. The primary outcome was 30 day death. Secondary outcomes included one year survival and in hospital major complications.

RESULTS

Among 11 474 patients, 10 539 (91.8%) were independently ambulatory pre-operatively. Propensity score matching resulted in 885 matched pairs. The impaired ambulation group, although older (mean 77.6 vs. 76.3 years; p = .001), showed comparable baseline characteristics. Post-operatively, the impaired ambulation group had higher cumulative in hospital complications and death as well as 30 day death. Even after adjustment for age, impaired pre-operative ambulation was associated with increased in hospital and 30 day death (hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.26 - 3.95; p = .006). Multivariable analysis demonstrated increasing cumulative risk of 30 day death in the setting of impaired pre-operative ambulatory status with age > 75 years requiring post-operative red blood cell transfusion > 2 units (HR 5.75, 95% CI 2.09 - 15.88; p < .001). Beyond 30 days, impaired pre-operative ambulation was not associated with increased one year death (HR 1.09, 95% CI 0.81 - 1.48; p = .570).

CONCLUSION

Among patients who underwent elective infrarenal EVAR in this matched analysis, impaired pre-operative ambulatory capacity was associated with an increased risk of in hospital and 30 day death, further compounded by advanced age and post-operative transfusion. As such, a threshold higher than the traditional size criteria should be considered in shared decision making when determining options for the management of abdominal aortic aneurysm in this high risk cohort.

Plasma proteomics reveals the potential causal impact of extracellular matrix proteins on abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA) is a common and life-threatening vascular disease. Genetic studies have identified numerous associated loci, many potentially encoding plasma proteins. However, the causal effects of plasma proteins on AAA have not been thoroughly studied. We used genetic causal inference approaches to identify plasma proteins that have a potential causal impact on AAA.

Methods

Causal inference was performed using two-sample Mendelian randomization (MR). For AAA, we utilized recently published summary statistics from a multi-population genome-wide association (GWAS) meta-analysis including 39,221 individuals with, and 1,086,107 individuals without AAA from 14 cohorts. We used protein quantitative trait loci (pQTLs) identified in two large-scale plasma-proteomics studies (deCODE and UKB-PPP) to generate genetic instruments. We tested 2,783 plasma proteins for possible causal effects on AAA using two-sample MR with inverse variance weighting and common sensitivity analyses to evaluate the MR assumptions. Bayesian colocalization and gene ontology (GO) enrichment analyses provided additional insights.

Results

MR identified 90 plasma proteins associated with AAA at FDR<0.05, with 25 supported by colocalization analysis. Among those supported by both MR and colocalization were previously experimentally validated proteins such as PCSK9 (OR 1.3; 95%CI 1.2-1.4; P<1e-10), LTBP4 (OR 3.4; 95%CI 2.6-4.6; P<1e-10) and COL6A3 (OR 0.6; 95%CI 0.5-0.7; P<1e-6). GO analysis revealed enrichment of proteins found in extracellular matrix (ECM, OR 7.8; P<1e-4), some with maximal mRNA levels in aortic tissue. Bi-directional MR suggested plasma level changes were not caused by liability to AAA itself. We then investigated whether variants responsible for expression changes in the aorta also influenced plasma levels and AAA risk. Colocalization analysis showed that an aortic expression quantitative trait locus (eQTL) for COL6A3, and a splicing quantitative trait locus (sQTL) for LTBP4 colocalized with their respective plasma pQTLs and AAA signals (posterior probabilities 0.84 and 0.89, respectively).

Conclusions

Our results highlight proteins and pathways with potential causal effects on AAA, providing a foundation for future functional experiments. These findings suggest a possible causal pathway whereby genetic variation affecting ECM proteins expressed in the aortic wall cause their levels to change in blood plasma, influencing development of AAA.

The Impact of Body Composition on Mortality and Hospital Length of Stay after Endovascular and Open Aortic Aneurysm Repair: A Retrospective Cohort Study

Background: Sarcopenia is an indicator of preoperative frailty and a patient-specific risk factor for poor prognosis in elderly surgical patients. Some studies have explored the prognostic significance of body composition parameters in relation to perioperative mortality after aortic repair and to mid- and long-term survival following endovascular aneurysm repair (EVAR). This study aimed to comprehensively investigate the effects of various body composition parameters, including but not limited to sarcopenia, on short- and long-term mortality as well as the length of hospital stay in two large cohorts of patients undergoing open surgical aortic repair (OSR) or EVAR. Methods: A single-institution retrospective cohort study included patients who underwent EVAR or OSR from January 2010 to December 2017. Several parameters of body composition on axial CT angiography images were analyzed, such as skeletal muscle area (SMA) with derived skeletal muscle index (SMI), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT). Results: 477 patients were included: 250 treated by OSR and 227 by EVAR; the mean age was 70.8 years (OSR) and 76.3 years (EVAR), with a mean follow-up of 54 months. Sarcopenia was associated with a prolonged length of hospital stay in EVAR patients but not in OSR patients (β coefficient 3.22; p-value 0.022 vs. β coefficient 0.391; p-value 0.696). Sarcopenia was an elevated one-year mortality risk post-EVAR compared to those without sarcopenia (p-value for the log-rank test 0.05). SMA and SMI were associated with long-term mortality in EVAR patients even after adjusting for multiple confounders (HR 0.98, p-value 0.003; HR 0.97, p-value 0.032). The analysis of the OSR cohort did not show a significant correlation between short- and long-term mortality and sarcopenia indicators. Conclusions: The results suggest that body composition could predict increased mortality and longer hospital stays in patients undergoing EVAR procedures. These findings were not confirmed in the cohort of patients who underwent OSR. Patients with sarcopenia and pre-operative malnutrition should be critically assessed to define the indication for treatment in this predominantly elderly and morbid cohort, despite EVAR procedures being less invasive. Body composition evaluation is an inexpensive and reproducible tool that can contribute to an improved decision-making process by identifying patients who will benefit most from EVAR, ensuring a more personalized and cost-effective treatment strategy. Further studies are planned to explore the added value of integrating body composition into a comprehensive risk stratification before aortic surgery.

Long-Term Outcomes in Patients Managed with the EndurantTM Endograft under Elective Setting

Background/Objectives: Device selection during endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) remains an important issue for ensuring endograft durability. This study evaluated the early and follow-up outcomes of elective EVAR with the Endurant platform. Methods: A single-center retrospective analysis was conducted including consecutive elective EVAR procedures with the Endurant II/IIs (2008 to 2024) device. Primary outcomes were technical success, mortality and major complications at 30 days. Survival, endoleak I/III and freedom from reintervention were secondary outcomes. Cox proportional hazards models were employed for risk-adjusted follow-up outcomes. Results: In total, 361 patients were included (72.7 ± 7 years; 96% males; mean AAA diameter 62 ± 14 mm); 92% received a bifurcated device, and 89% conformed to the instructions for use. Technical success was 99.7%. Intra-operative adjunctive procedures included 4.4% proximal cuffs and 1.7% endoanchors. The thirty-day mortality rate was 0.6%, and the major complication rate was 4.1%. Survival was 81% (SE 4.8%), 72% (SE 6.4%) and 52% (SE 9.2%) at 4, 6 and 8 years, with aneurysm-related mortality at 1.7%. Freedom from endoleak Ia was 76% (SE 7.3%) at 6 years, freedom from endoleak Ib was 79% (SE 7.4%) at 7 years and freedom from endoleak III was 94% (SE 3.7%) at 5 years. Freedom from reintervention was 71% (SE 6.1%) and 55% (SE 7.9%) at 5 and 7 years, respectively. No device-related co-factor affected long-term outcomes. Conclusions: Endurant II/IIs endograft is a safe and effective EVAR solution with excellent early outcomes and low long-term aneurysm-related mortality. The need for reintervention in the long term affected less than 50% of cases.

Preoperative Congestive Heart Failure Is Associated with Higher 30-Day Myocardial Infarction and Pneumonia after Endovascular Repair of Abdominal Aortic Aneurysm

INTRODUCTION

Preoperative congestive heart failure (CHF) is associated with higher postoperative mortality and complications in noncardiac surgery. However, postoperative outcomes for patients with preoperative CHF undergoing endovascular aneurysm repair (EVAR) have not been thoroughly established. This study evaluated the effect of preoperative CHF on 30-day outcomes following nonemergent intact EVAR using a large-scale national registry.

METHODS

Patients who had infrarenal EVAR were identified in the ACS-NSQIP database from 2012 to 2022. A 1:5 propensity-score matching was used to match demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, anesthesia, and concomitant procedures between patients with and without preoperative CHF. Thirty-day postoperative outcomes were examined.

RESULTS

467 (2.84%) CHF patients underwent intact EVAR. Meanwhile, 15,996 non-CHF patients underwent EVAR, where 2,248 of them were matched to all CHF patients. Patients with and without preoperative CHF had comparable 30-day mortality (3.02% vs. 2.62%, p = 0.64). However, CHF patients had higher myocardial infarction (3.02% vs. 1.47%, p = 0.03), pneumonia (3.23% vs. 1.73%, p = 0.04), 30-day readmission (p = 0.01), and longer length of stay (p < 0.01).

CONCLUSION

While patients with and without preoperative CHF had comparable 30-day mortality rates, those with CHF faced higher risks of cardiopulmonary complications. Effective management of preoperative CHF may help prevent postoperative complications in these patients.

Lipoprotein (a) is associated with increased risk of Abdominal Aortic Aneurysm

Introduction

Lipoprotein(a) (Lp(a)) is a circulating apolipoprotein B (ApoB) containing particle that has been observationally linked to atherosclerotic cardiovascular disease and is the target of emerging therapeutics. Recent work has highlighted the role of circulating lipoproteins in abdominal aortic aneurysm (AAA). We sought to triangulate human observational and genetic evidence to evaluate the role of Lp(a) in AAA.

Methods

We tested the association between circulating levels of Lp(a) and clinically diagnosed abdominal aortic aneurysms while controlling for traditional AAA risk factors and levels of ApoB using logistic regression among 795 individuals with and 374,772 individuals without AAA in the UK Biobank (UKB). Multivariable Mendelian randomization (MVMR) was used to test for putatively causal associations between Lp(a) and AAA controlling for ApoB. Genetic instruments for Lp(a) and ApoB were created from genome-wide association studies (GWAS) of Lp(a) and ApoB comprising 335,796 and 418,505 UKB participants, respectively. The instruments were tested for association with AAA using data from a GWAS of 39,221 individuals with and 1,086,107 without AAA.

Results

Elevated Lp(a) levels were observationally associated with an increased risk of AAA (OR 1.04 per 10 nmol/L Lp(a); 95%CI 1.02-1.05; P<0.01). Clinically elevated Lp(a) levels (>150nmol/L) were likewise associated with an increased risk of AAA (OR 1.47; 95% CI 1.15-1.88; P < 0.01) when compared to individuals with Lp(a) levels <150nmol/L. MVMR confirmed a significant, ApoB-independent association between increased Lp(a) and increased risk of AAA (OR 1.13 per SD increase in Lp(a); 95%CI 1.02-1.24; P<0.02).

Conclusion

Both observational and genetic analyses support an association between increased Lp(a) and AAA risk that is independent of ApoB. These findings suggest that Lp(a) may be a therapeutic target for AAA and drive the inclusion of AAA as an outcome in clinical trials of Lp(a) antagonists.

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-1β, and IL-8 were upregulated in AAA. CXCL1 silencing downregulated NF-κB, interleukin-1β, 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.

High proportion of undiagnosed diabetes in patients surgically treated for infrarenal abdominal aortic aneurysm: findings from the multicentre Norwegian Aortic Aneurysm and Diabetes (ABANDIA) Study

BACKGROUND

The aim was to investigate the total prevalence of known and undiagnosed diabetes mellitus (DM), and the association of DM with perioperative complications following elective, infrarenal, open surgical (OSR) or endovascular (EVAR), Abdominal Aortic Aneurysm (AAA) repair.

METHODS

In this Norwegian prospective multicentre study, 877 patients underwent preoperative screening for DM by HbA1c measurements from November 2017 to December 2020. Diabetes was defined as screening detected HbA1c ≥ 48 mmol/mol (6.5%) or previously diagnosed diabetes. The association of DM with in-hospital complications, length of stay, and 30-day mortality rate were evaluated using adjusted and unadjusted logistic regression models.

RESULTS

The total prevalence of DM was 15% (95% CI 13%,17%), of which 25% of the DM cases (95% CI 18%,33%) were undiagnosed upon admission for AAA surgery. The OSR to EVAR ratio was 52% versus 48%, with similar distribution among DM patients, and no differences in the prevalence of known and undiagnosed DM in the EVAR versus the OSR group. Total 30-day mortality rate was 0.6% (5/877). Sixty-six organ-related complications occurred in 58 (7%) of the patients. DM was not statistically significantly associated with a higher risk of in-hospital organ-related complications (OR 1.23, 95% CI 0.57,2.39, p = 0.57), procedure-related complications (OR 1.48, 95% CI 0.79,2.63, p = 0.20), 30-day mortality (p = 0.09) or length of stay (HR 1.06, 95% CI 0.88,1.28, p = 0.54). According to post-hoc-analyses, organ-related complications were more frequent in patients with newly diagnosed DM (n = 32) than in non-DM patients (OR 4.92; 95% CI 1.53,14.3, p = 0.005).

CONCLUSION

Twenty-five percent of all DM cases were undiagnosed at the time of AAA surgery. Based on post-hoc analyses, undiagnosed DM seems to be associated with an increased risk of organ related complications following AAA surgery. This study suggests universal DM screening in AAA patients to reduce the number of DM patients being undiagnosed and to improve proactive diabetes care in this population. The results from post-hoc analyses should be confirmed in future studies.

Highly sensitive magnetic particle imaging of abdominal aortic aneurysm NETosis with anti-Ly6G iron oxide nanoparticles

Abdominal aortic aneurysms (AAA) are a significant health concern in developed countries due to their considerable mortality rate. The crucial factor of the progression of AAA is the release of neutrophils and neutrophil extracellular traps (NETs). Magnetic particle imaging (MPI) is a new imaging technique that offers the capability to detect superparamagnetic iron oxide nanoparticles (SPION) with exceptional sensitivity. We aimed to investigate the functional imaging of MPI for the detection and monitoring of neutrophil infiltration within AAA. A novel multimodal imaging agent targeting neutrophils, PEG-Fe3O4-Ly6G-Cy7 nanoparticles (Ly6G NPs), were designed by coupling Fe3O4 nanoparticles with Ly6G antibodies and Cy7. The targeting and sensitivity of Ly6G NPs were assessed using MPI and fluorescence imaging (FLI) in the AAA mouse model. After the inhibition of NETosis, the degree of neutrophil infiltration and AAA severity were assessed using MPI with Ly6G NPs. Ly6G NPs accurately localized and quantitatively analyzed AAA lesion sites in mice using MPI/FLI/CT. Compared to the control group, elevated MPI and FLI signal intensities were detected at the abdominal aortic lesion site, and neutrophil infiltration and NETs accumulation were detected by histological analysis in the AAA models. After the inhibition of NETs accumulation in vivo, pathological damage in the abdominal aorta was significantly reduced, along with a decrease in the accumulation of Ly6G NPs and MPI signals. This multimodal MPI strategy revealed that nanoparticles targeting Ly6G can be used to detect neutrophil infiltration within AAA and monitor AAA severity.

Hormonal influence: unraveling the impact of sex hormones on vascular smooth muscle cells

Sex hormones play a pivotal role as endocrine hormones that exert profound effects on the biological characteristics and vascular function of vascular smooth muscle cells (VSMCs). By modulating intracellular signaling pathways, activating nuclear receptors, and regulating gene expression, sex hormones intricately influence the morphology, function, and physiological state of VSMCs, thereby impacting the biological properties of vascular contraction, relaxation, and growth. Increasing evidence suggests that abnormal phenotypic changes in VSMCs contribute to the initiation of vascular diseases, including atherosclerosis. Therefore, understanding the factors governing phenotypic alterations in VSMCs and elucidating the underlying mechanisms can provide crucial insights for refining interventions targeted at vascular diseases. Additionally, the varying levels of different types of sex hormones in the human body, influenced by sex and age, may also affect the phenotypic conversion of VSMCs. This review aims to explore the influence of sex hormones on the phenotypic switching of VSMCs and the development of associated vascular diseases in the human body.

Computer tomography-based assessment of perivascular adipose tissue in patients with abdominal aortic aneurysms

This retrospective study investigates perivascular adipose tissue (PVAT) alterations in CT as a marker of inflammation in patients with abdominal aortic aneurysms (AAA). 100 abdominal CT scans of patients with abdominal aortic aneurysms and 100 age and sex matched controls without underlying aortic disease were included. Artificial Intelligence (AI) assisted segmentation of the aorta and the surrounding adipose tissue was performed. Adipose tissue density was measured in Hounsfield units (HU) close (2-5mm, HUclose) and distant (10-12mm, HUdistant) to the aortic wall. To investigate alterations in adipose tissue density close to the aorta (HUclose) as a potential marker of inflammation, we calculated the difference HUΔ = HUclose-HUdistant and the fat attenuation ratio HUratio = HUclose/HUdistant as normalized attenuation measures. These two markers were compared i) inter-individually between AAA patients and controls and ii) intra-individually between the aneurysmal and non-aneurysmal segments in AAA patients. Since most AAAs are generally observed infrarenal, the aneurysmal section of the AAA patients was compared with the infrarenal section of the aorta of the control patients. In inter-individual comparisons, higher HUΔ and a lower HUratio were observed (aneurysmal: 8.9 ± 5.1 HU vs. control: 6.9 ± 4.8 HU, p-value = 0.006; aneurysmal: 89.8 ± 5.7% vs. control: 92.1 ± 5.5% p-value = 0.004). In intra-individual comparisons, higher HUΔ and lower HUratio were observed (aneurysmal: 8.9 ± 5.1 HU vs. non-aneurysmal: 5.5 ± 4.1 HU, p-value < 0.001; aneurysmal: 89.8 ± 5.7% vs. non-aneurysmal 93.3 ± 4.9%, p-value < 0.001). The results indicate PVAT density alterations in AAA patients. This motivates further research to establish non-invasive imaging markers for vascular and perivascular inflammation in AAA.

Outcome analysis of the surgical team in open surgical repair of intact abdominal aortic aneurysm surgery

OBJECTIVES

To analyze how the experience of the surgical team went to impact the outcomes after open surgical repair (OSR) of intact abdominal aortic aneurysms (AAAs).

METHODS

This is a single-center, observational cohort study with retrospective analysis of all OR for intact AAA performed between 1 January 2010 and 31 December 2022. The primary outcome was survival at 30 days and in follow-up, and a composite outcome of mortality and major complication. The secondary outcome was freedom from aorta-related reintervention. All outcomes were stratified according to the experience of the operating team (surgeons and anesthesiology).

RESULTS

We analyzed 103 (7.2%) patients: 97 (94.2%) males and 6 (5.8%) females. The mean age was 76 ± 8 years (range, 55-93). The best possible team composition was present in 52 (50.5%) interventions. The follow-up index was 0.82 ± 0.18 (range, 0.6-1.0). Mean follow-up duration was 59 ± 43 months (range, 0-158). We observed no differences between teams in major complications (best, 17.3% vs mixed, 21.6%; OR: 0.4, P = 0.622), 30 days mortality (best, 0% vs mixed, 5.9%; OR: 7.6, P = 0.118) and composite outcome (best, 11.5% vs mixed, 17.6%; OR: 0.8, P = 0.416). Cox regression analysis identified the best possible team as a protective factor against the need for reintervention (hazard ratio: 0.2; 95% confidence interval: 0.06-0.88, P = 0.032).

CONCLUSIONS

In our experience, OR of AAA yielded satisfactory results in terms of safety and efficacy independently of the team's experience. A more experienced team may protect against aorta-related reintervention.

Preoperative risk factors for 1-year mortality in patients undergoing fenestrated endovascular aortic aneurysm repair in the US Aortic Research Consortium

BACKGROUND

Early survival (1-year) after elective repair of complex abdominal aortic aneurysms (AAA) or thoracoabdominal aortic aneurysms (TAAA) can be used as an indicator of successful repair and provides a reasonable countermeasure to the annual rupture risk based on diameter. We aimed to identify preoperative factors associated with 1-year mortality after fenestrated or branched endovascular aortic repair (F/BEVAR) and develop a predictive model for 1-year mortality based on patient-specific risk profiles.

METHODS

The US-Aortic Research Consortium database was queried for all patients undergoing elective F/BEVAR for complex AAA (cAAA) or TAAA from 2005 to 2022. The primary outcome was 1-year survival based on preoperative risk profile. Multivariable Cox regression was used to determine preoperative variables associated with 1-year mortality overall and by extent of aortic pathology. Logistic regression was performed to build a predictive model for 1-year mortality based on number of risk factors present.

RESULTS

A total of 2099 patients met the inclusion criteria for this study (cAAA: n = 709 [34.3%]; type 1-3 TAAA: n = 777 [37.6%]; type 4-5 TAAA: n = 580 [28.1%]). Multivariable Cox regression identified the following significant risk factors associated with 1-year mortality: current smoker, chronic obstructive pulmonary disease, congestive heart failure (CHF), aortic diameter >7 cm, age >75 years, extent 1-3, creatinine >1.7 mg/dL, and hematocrit <36%. When stratified by extent of aortic involvement, multivariable Cox regression revealed risk factors for 1-year mortality in cAAA (CHF maximum aortic diameter >7 cm, hematocrit <36 mg/dL, and current smoking status), type 1-3 TAAA (chronic obstructive pulmonary disease, CHF, and age >75 years), and type 4-5 TAAA (age >75 years, creatinine >1.7 mg/dL, and hematocrit <36 mg/dL). Logistic regression was then used to develop a predictive model for 1-year mortality based on patient risk profile. Appraisal of the model revealed an area under the curve of 0.64 (P < .001), and an observed to expected ratio of 0.85.

CONCLUSIONS

This study describes multiple risk factors associated with an increase in 1-year mortality after F/BEVAR. Given that elective repair of cAAA or TAAA is offered to some patients in whom future rupture risk outweighs operative risk, these findings suggest that highly comorbid patients with smaller aneurysms may not benefit from repair. Descriptive and predictive models for 1-year mortality based on patient risk profiles can serve as an adjunct in clinical decision-making when considering elective F/BEVAR.

Side branch embolization before endovascular abdominal aortic aneurysm repair to prevent type II endoleak: A prospective multicenter study

PURPOSE

The purpose of the study was to evaluate the efficacy and safety of pre-emptive transcatheter arterial embolization (P-TAE) of aortic side branches to prevent type II endoleak in patients with abdominal aortic aneurysm after endovascular abdominal aneurysm repair (EVAR).

MATERIALS AND METHODS

This multicenter, prospective, single-arm trial enrolled 100 patients with abdominal aortic aneurysm from nine hospitals between 2018 and 2021. There were 85 men and 15 women, with a mean age of 79.6 ± 6.0 (standard deviation) years (range: 65-97 years). P-TAE was attempted for patent aortic side branches, including the inferior mesenteric artery, lumbar arteries, and other branches. The primary endpoint was late type II endoleak incidence at 6 months post-repair. Secondary endpoints included changes in aneurysmal sac diameter at 6- and 12 months, complications, re-intervention, and aneurysm-related mortality. Aneurysm sac changes at 6- and 12 months was compared between the late and no-late type II endoleak groups.

RESULTS

Coil embolization was successful in 80.9% (321/397) of patent aortic side branches, including 86.3% of the inferior mesenteric arteries, 80.3% of lumbar arteries, and 55.6% of other branches without severe adverse events. Late type II endoleak incidence at 6 months was 8.9% (8/90; 95% confidence interval: 3.9-16.8%). Aneurysm sac shrinkage > 5 mm was observed in 41.1% (37/90) and 55.3% (47/85) of the patients at 6- and 12-months post-EVAR, respectively. Patients with late type II endoleak had less aneurysm sac shrinkage than those without type II endoleak at 12 months (-0.2 mm vs. -6.0 mm; P = 0.040). No patients required re-intervention for type II endoleak, and no aneurysm-related mortalities occurred.

CONCLUSION

P-TAE is safe and effective in preventing type II endoleak, leading to early sac shrinkage at 12 months following EVAR.

The sac evolution imaging follow-up after endovascular aortic repair: An international expert opinion-based Delphi consensus study

OBJECTIVE

Management of follow-up protocols after endovascular aortic repair (EVAR) varies significantly between centers and is not standardized according to sac regression. By designing an international expert-based Delphi consensus, the study aimed to create recommendations on follow-up after EVAR according to sac evolution.

METHODS

Eight facilitators created appropriate statements regarding the study topic that were voted, using a 4-point Likert scale, by a selected panel of international experts using a three-round modified Delphi consensus process. Based on the experts' responses, only those statements reaching a grade A (full agreement ≥75%) or B (overall agreement ≥80% and full disagreement <5%) were included in the final document.

RESULTS

One-hundred and seventy-four participants were included in the final analysis, and each voted the initial 29 statements related to the definition of sac regression (Q1-Q9), EVAR follow-up (Q10-Q14), and the assessment and role of sac regression during follow-up (Q15-Q29). At the end of the process, 2 statements (6.9%) were rejected, 9 statements (31%) received a grade B consensus strength, and 18 (62.1%) reached a grade A consensus strength. Of 27 final statements, 15 (55.6%) were classified as grade I, whereas 12 (44.4%) were classified as grade II. Experts agreed that sac regression should be considered an important indicator of EVAR success and always be assessed during follow-up after EVAR.

CONCLUSIONS

Based on the elevated strength and high consistency of this international expert-based Delphi consensus, most of the statements might guide the current clinical management of follow-up after EVAR according to the sac regression. Future studies are needed to clarify debated issues.

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.

The Role of Narrow Aortic Bifurcation in Affecting EVAR Treatment and Outcomes

BACKGROUND

The narrow aortic bifurcation (NAB) is considered a risk factor for endograft thrombosis after aorto-biiliac endovascular aneurysm repair (EVAR) for aortic or iliac aneurysm. Nowadays, no consensus on the threshold diameter for the definition of NAB is reached and other aortic bifurcation features are rarely considered. The aim of the study is to assess the EVAR outcomes using bifurcated endograft according to anatomical characteristics of aortic bifurcation.

METHODS

The study included patients treated with primary EVAR from 2016 to 2022. A retrospective analysis of single-center prospectively collected database was performed. Patients were classified in standard aortic bifurcation (SAB) (aortic bifurcation diameter >20 mm), NAB (≤20 mm and >16 mm), and extremely NAB (eNAB) (≤16 mm). The 3 groups were compared in terms of patient demographics, risk factors, procedure setting (elective or urgent/emergent), and type of deployed endograft. In NAB and eNAB groups, severe calcification (SC) and length of stenotic aortic bifurcation >10 mm (long-NAB) were assessed from preoperative imaging. In SAB, NAB, and eNAB groups, following outcomes were evaluated: rate of intraoperative iliac endograft stenting (unilateral or kissing stenting), primary patency (PP), freedom from endograft-related reintervention, and overall survival during follow-up.

RESULTS

The total number of deployed aorto-biiliac endografts was 365 (mean age: 76.6 ± 7.4 years; male 89.3%): SAB 298 (81.6%), NAB 57 (15.6%), and eNAB 10 (2.7%) cases. Female gender, chronic obstructive pulmonary disease patients, and active smokers were more frequent in patients with smaller aortic bifurcation diameter (P = 0.002, 0.039, and 0.010, respectively). In NAB and eNAB groups, SC was reported in 18/67 cases (26.9%) and long-NAB in 15/67 cases (25.4%). Patients with eNAB have more frequent SC of aortic bifurcation (60% vs. NAB 21.1%, P = 0.018) and long-NAB (50% vs. NAB 17.5%, P = 0.023). In SAB, NAB, and eNAB, intraoperative iliac endograft stenting was performed in 34/298 (11.4%), 9/57 (15.8%), and 5/10 (50%), respectively (P = 0.001). Kissing stenting was performed more frequently in groups with smaller aortic bifurcation diameter (P = 0.010). Mean follow-up was 30.2 ± 21.5 months. At 1, 3, and 5 years, PP was 98.5%, 96.6%, and 95.6%, respectively. eNAB had lower rate of PP compared to NAB group (P = 0.030). Long-NAB had lower rate of PP (P = 0.035). At 1, 3, and 5 years, endograft-related reintervention was 96.8%, 86.7%, and 76.7%, respectively, with no differences between 3 groups (P = 0.423). At 1, 3, and 5 years, survival was 92.5%, 77.6%, and 58.1%, respectively, with no difference between SAB, NAB, and eNAB (P = 0.673).

CONCLUSIONS

Female gender, chronic obstructive pulmonary disease patients, and active smokers have more frequently smaller aortic bifurcation diameter. eNAB patients have more challenging anatomical characteristics compared with NAB group, requiring higher rate of intraoperative stenting, especially kissing stenting. Mid-term PP seems to be negatively influenced by aortic bifurcation ≤16 mm and long-NAB.

Implications and late outcomes of type II endoleaks after endovascular aneurysm repair

OBJECTIVE

Type II endoleaks (T2ELs) are the most common cause of reintervention after endovascular aneurysm repair (EVAR). Although most resolve spontaneously, the long-term implications of T2ELs remain elusive. We aim to evaluate the impact of persistent and late T2ELs on clinical outcomes after EVAR.

METHODS

This was a single-institution retrospective review of patients who underwent EVAR for degenerative infrarenal abdominal aortic aneurysm between January 2010 and June 2022 with no type I (T1EL) or III (T3EL) endoleak seen at EVAR completion. Patients were categorized based on T2EL status. Group 1 included patients with never detected or transient T2ELs (detected at EVAR completion but not after). Group 2 encompassed persistent T2ELs (seen at EVAR completion and again during follow-up) and late T2ELs (detected for the first time at any point during follow-up). Time-to-event analysis was conducted using a time-dependent approach to T2EL status. Primary outcomes included freedom from sac enlargement (SE), aneurysm-related reinterventions, and overall survival.

RESULTS

A total of 803 patients met inclusion criteria. Group 1 included 418 patients (52%), of which 85% had no T2ELs and 15% had transient T2ELs. Group 2 had 385 patients; 23% had persistent T2ELs, and 77% developed a new T2EL. Patients in group 1 had a higher prevalence of smoking (88% vs 83%; P < .001), chronic obstructive pulmonary disease (33% vs 25%; P = .008), chronic kidney disease (13% vs 8%; P = .021), and a higher mean Society for Vascular Surgery score (7 vs 6 points; P = .049). No differences were found in aneurysm diameter or morphology. Mean follow-up was 5 years for the entire cohort. In Group 2, 58 patients (15%) underwent T2EL treatment, most commonly transarterial embolization. At 10 years after EVAR, Group 2 was associated with lower freedom from SE (P < .001) and abdominal aortic aneurysm-related reinterventions (P < .001) and comparable overall survival (P = .42). More T1ELs were detected during follow-up in Group 2 (6 [1%] vs 20 [5%]; P = .004), with 15 (75%) of these detected at a median of 3 years after the T2EL. No difference between groups was observed in explant (0.7% vs 2.1%; P = .130) or aneurysm rupture (0.5% vs 1.3%; P = .269) rates.

CONCLUSIONS

One-half of patients treated with infrarenal EVAR developed persistent/late T2ELs, which are associated with a higher risk of SE and reinterventions. No difference in overall survival or aneurysm rupture risk was seen at 10 years, based on T2EL status or T2EL intervention. A conservative approach to T2ELs may be appropriate for most patients with absent T1ELs or T3ELs.

Variability in short-term mortality following repair of ruptured abdominal aortic aneurysms across centers and physicians

BACKGROUND

Variation in the care management of repairs for ruptured infrarenal abdominal aortic aneurysms between centers and physicians, such as procedural volumes, may explain differences in mortality outcomes. First, we quantified the center and physician variability associated with 30- and 90-day mortality risk after ruptured open surgical repair (rOSR) and ruptured endovascular aneurysm repair (rEVAR). Second, we explored wheter part of this variability was attributable to procedural volume at the center and physician levels.

METHODS

Two cohorts including rOSR and rEVAR procedures between 2013 and 2019 were analyzed from the Vascular Quality Initiative database. Thirty- and 90-day all-cause mortality rates were derived from linked Medicare claims data. The median odds ratio (MOR) (median mortality risk from low- to high-risk cluster) and intraclass correlation coefficient (ICC) (variability attributable to each cluster) for 30- and 90-day mortality risks associated with center and physician variability were derived using patient-level adjusted multilevel logistic regression models. Procedural volume was calculated at the center and physician levels and stratified by quartiles. The models were sequentially adjusted for volumes, and the difference in ICCs (without vs with accounting for volume) was calculated to describe the center and physician variability in mortality risk attributable to volumes.

RESULTS

We included 450 rOSRs (mean age, 74.5 ± 7.6 years; 23.5% female) and 752 rEVARs (76.4 ± 8.4 years; 26.1% female). After rOSRs, the 30- and 90-day mortality rates were 32.9% and 38.7%, respectively. No variability across centers and physicians was noted (30- and 90-day MORs ≈1 and ICCs ≈0%). Neither center nor physician volume was associated with 30-day (P = .477 and P = .796) or 90-day mortality (P = .098 and P = .559). After rEVAR, the 30- and 90-day mortality rates were 21.3% and 25.5%, respectively. Significant center variability (30-day MOR, 1.82 [95% confidence interval (CI), 1.33-2.22]; ICC, 11% [95% CI, 2%-36%]; and 90-day MOR, 1.76 [95% CI, 1.37-2.09]; ICC, 10% [95% CI, 3%-30%]), but negligeable variability across physicians (30- and 90-day MORs ≈1 and ICCs ≈0%) were noted. Neither center nor physician volume were associated with 30-day (P = .076 and P = .336) or 90-day mortality risk (P = .066 and P = .584). The center variability attributable to procedural volumes was negligeable (difference in ICCs, 1% for 30-day mortality; 0% for 90-day mortality).

CONCLUSIONS

Variability in practice from center to center was associated with short-term mortality outcomes in rEVAR, but not for rOSR. Physician variability was not associated with short-term mortality for rOSR or rEVAR. Annualized center and physician volumes did not significantly explain these associations. Further work is needed to identify center-level factors affecting the quality of care and outcomes for ruptured abdominal aortic aneurysms.

Postdissection aortic aneurysm sac enlargement after fenestrated and branched endovascular aortic aneurysm repair

OBJECTIVES

Aneurysm sac changes after fenestrated-branched endovascular aneurysm repair (FBEVAR) for postdissection thoracoabdominal aortic aneurysms (PD-TAAs) are poorly understood. Partial thrombosis of the false lumen and endoleaks may impair sac regression. To characterize sac changes after FBEVAR for PD-TAAs, this study examined midterm results and predictors for sac enlargement.

METHODS

FBEVARs performed for PD-TAAs in 10 physician-sponsored investigational device exemption studies from 2008 to 2023 were analyzed. The maximum aortic aneurysm diameter was compared between the 30-day computed tomography angiogram and follow-up imaging studies. Aneurysm sac enlargement was defined as an increase in diameter of ≥5 mm. Kaplan-Meier curves and Cox regression were used to evaluate sac enlargement and midterm FBEVAR outcomes.

RESULTS

Among 3296 FBEVARs, 290 patients (72.4% male; median age, 68.4 years) were treated for PD-TAAs. Most aneurysms treated were extent II (72%) and III (12%). Mean aneurysm diameter was 66.5 ± 11.2 mm. Mortality at 30 days was 1.4%. At a mean follow-up of 2.9 ± 1.9 years, at least one follow-up imaging study revealed sac enlargement in 43 patients (15%), sac regression in 115 patients (40%), and neither enlargement nor regression in 137 (47%); 5 (2%) demonstrated both expansion and regression during follow-up. Freedom from aneurysm sac enlargement was 93%, 82%, and 80% at 1, 3, and 5 years, respectively. Overall, endoleaks were detected in 27 patients (63%) with sac enlargement and 143 patients (58%) without enlargement (P = .54). Sac enlargement was significantly more frequent among older patients (mean age at the index procedure, 70.2 ± 8.9 years vs 66.5 ± 11 years; P = .04) and those with type II endoleaks at 1 year (74% vs 52%; P = .031). Cox regression revealed age >70 years at baseline (hazard ratio [HR], 2.146; 95% confidence interval [CI], 1.167-3.944; P = .010) and presence of type II endoleak at 1 year (HR, 2.25; 95% CI, 1.07-4.79; P = .032) were independent predictors of sac enlargement. Patient survival was 92%, 81%, and 68% at 1, 3, and 5 years, respectively. Cumulative target vessel instability was 7%, and aneurysm-related mortality was 2% at 5 years. At least 42% of patients required secondary interventions. Sac enlargement did not affect patient survival.

CONCLUSIONS

Aneurysm sac enlargement occurs in 15% of patients after FBEVAR for PD-TAAs. Elderly patients (>70 years at baseline) and those with type II endoleaks at 1 year may need closer monitoring and secondary interventions to prevent sac enlargement. Despite sac enlargement in some patients, aneurysm-related mortality at 5 years remains low and overall survival was not associated with sac enlargement.

Hemoglobin homeostasis in abdominal aortic aneurysm: diagnostic and prognostic potential of hemoglobin/heme and scavenger molecules

BACKGROUND

There is increasing evidence implicating hemoglobin/heme and their scavengers in oxidative stress-mediated pathologies, but information is limited in abdominal aortic aneurysm (AAA).

METHODS AND RESULTS

In this case-control study, we assessed heme/heme-related markers in 142 men with AAA and 279 men with a normal aortic diameter consecutively recruited from an ultrasound screening program in Sweden. Enzyme-linked immunosorbent assays (ELISAs) were used to measure heme oxygenase-1 (HO-1) and hemopexin (Hpx) plasma levels, colorimetric assays for cell-free heme and whole blood hemoglobin (Hb) levels, and droplet digital PCR (ddPCR) and real-time PCR to determine haptoglobin (Hp) (pheno)type and genotype, respectively. Hpx and heme plasma levels at baseline were elevated, while HO-1 levels were lower in men with AAA (p < 0.001) and were significantly associated with AAA prevalence independently of potential confounders. A combination of heme and HO-1 showed the best diagnostic potential based on the area under the curve (AUC): 0.76, sensitivity: 80%, specificity: 48%. Additionally, when previously described inflammatory biomarker interleukin-6 (IL-6), was added to our model it significantly improved the diagnostic value (AUC: 0.87, sensitivity: 80%, specificity: 79%) compared to IL-6 alone (AUC: 0.73, sensitivity: 80%, specificity: 49%). Finally, Hb (positively) and Hpx (negatively) levels at baseline were associated with AAA growth rate (mm/year), and their combination showed the best prognostic value for discriminating fast and slow-growing AAA (AUC: 0.76, sensitivity: 80%, specificity: 62%).

CONCLUSIONS

This study reports the distinct disruption of heme and related markers in both the development and progression of AAA, underscoring their potential in aiding risk stratification and therapeutic strategies.

The Enzen Trial: Analysis of EVAR Endoprosthesis Zenith and Endurant for Infrarenal Aortoiliac Aneurysms Regarding Outcomes, Endoleaks, and Reinterventions

OBJECTIVE

The main objective of this paper is to analyze the outcomes regarding endoleaks, reinterventions, and death related to aneurysm complications in patients submitted to endovascular repair (EVAR) for abdominal aortoiliac aneurysm (AAA) using Endurant II (Medtronic) and Zenith Flex (Cook) endografts.

METHODS

This was a prospective, consecutive cohort study of patients with AAA who underwent EVAR between January 2019 and December 2022. Two groups of patients were evaluated: Group Endurant (patients submitted to EVAR with the use of Endurant II) and Group Zenith (patients submitted to EVAR with the use of Zenith Flex).

RESULTS

A total of 156 patients were evaluated. Group Zenith (67 patients, 42.9%) and Group Endurant (89 patients, 57.1%). The perioperative mortality was 5.1%, eight patients (six patients Group Zenith, and two patients Group Endurant, p=0.054). There were 28 patients (17.9%) submitted to urgent repair of the aneurysm (expansion or rupture), with no differences among the groups. There were 36 cases (23.1%) of later endoleak, with a higher incidence in Zenith group (23 patients, 34.3%) than Endurant group (13 patients, 14.6%, p=0.002), most of them Type II endoleak (21 patients, 13.4%). There were 12 cases of Type I endoleak, also with a higher prevalence in Zenith group (13.4%) than Endurant group (3.4%, p=0.002). Moreover, regarding limb graft occlusion (LGO), there were nine patients (5.8%), with a higher prevalence in Zenith group (9%) than Endurant group (3.4%, p=0.045). The overall survival in a Kaplan-Meier at 720 days was 82.3% in the Zenith group and 89.1% in the Endurant group, with no statistical significance among the groups (p=0.09). The freedom from reintervention rates in a Kaplan-Meier at 720 days was 82.8% in the Zenith group and 93.2% in the Endurant group (p=0.001).

CONCLUSION

In this present study, Zenith endograft had higher rates of endoleaks, aneurysms related mortality, LGO and reinterventions than patients submitted to Endurant II endografts. The linear regression analysis showed that the presence of endoleaks, type of endograft device (Zenith graft) and limb graft occlusion were related to higher reintervention rates.

CLINICAL IMPACT

In this present study, Zenith endograft had higher rates of endoleaks, aneurysms related mortality, limb graft occlusions and reinterventions than patients submitted to Endurant II endografts. The main impact and the innovation that this article provides is an opportunity to evaluate and choose the best endograft suitable for the patient with AAA during EVAR.

Influence of Bridging Stent Graft Implantation into the Renal Artery during Complex Endovascular Aortic Procedures on the Renal Resistance Index

Comparative sonographic examination of the renal resistance index (RRI) can provide evidence of renal artery stenosis. The extent to which the RRI is changed after stent graft implantation is not known. The aim of this study was to investigate the influence of stent graft implantation into non-diseased renal arteries during endovascular treatment of pararenal aortic aneurysms on the RRI. Sonographic examinations of the kidneys were conducted using a GE ultrasound system. The evaluation was performed according to the European Society for Vascular Surgery (ESVS) 2D standard criteria. RRI values were determined in consecutive patients on the day before and after stent graft implantation and compared for each kidney. A total of 32 consecutive patients (73.9 ± 8.2 years, 5 females, 27 males) were treated with a fenestrated or branched aortic stent graft including bridging stent graft implantations into both renal arteries and received pre- and postinterventional examinations. Sonomorphologically, the examined kidneys were inconspicuous. The arborisation of the renal perfusion was preserved pre- and post-implantation. The RRI did not differ (0.66 ± 0.06 versus 0.67 ± 0.07; p = ns). Successful stent graft implantation into non-stenosed renal arteries did not lead to a relevant change in RRI. Therefore, the RRI is a suitable tool for assessing renal perfusion after fenestrated or branched endovascular aortic therapy.

Aortic aneurysms in a general population cohort: prevalence and risk factors in men and women

AIMS

The prevalence and difference in risk factors for having thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) in men compared with women in the general population is not well described. This study aimed to test the hypotheses that (i) cardiovascular risk factors for TAA and AAA differ and (ii) the prevalence of TAA and AAA is sex specific.

METHODS AND RESULTS

Aortic examination using computed tomography angiography was performed in 11 294 individuals (56% women), with a mean age of 62 (range 40-95) years participating in the Copenhagen General Population Study. TAAs were defined as an ascending aortic diameter ≥45 mm and a descending aortic diameter ≥35 mm, while AAAs were defined as an abdominal aortic diameter ≥30 mm. Demographic data were obtained from questionnaires. Overall prevalence of aortic aneurysms (AAs) in the study population included: total population 2.1%, men 4.0% and women 0.7% (P-value men vs. women P < 0.001). AAs were independently associated with male sex, increasing age, and body surface area (BSA). While TAAs were associated with hypertension, odds ratio (OR) = 2.0 [95% confidence interval (CI): 1.5-2.8], AAAs were associated with hypercholesterolaemia and smoking, OR = 2.4 (95% CI: 1.6-3.6) and 3.2 (95% CI: 1.9-5.4).

CONCLUSION

Subclinical AAs are four times more prevalent in men than in women. In both sexes, increasing age and BSA are risk factors for AAs of any anatomical location. Whereas arterial hypertension is a risk factor for TAAs, hypercholesterolaemia and smoking are risk factors for AAAs.

Diagnostic accuracy of microvascular flow imaging ultrasound for endoleak detection after endovascular aortic aneurysm repair: a systematic review and meta-analysis

The objective was to assess the diagnostic accuracy of microvascular flow imaging ultrasound (MVUS) for the detection of endoleak after endovascular aortic aneurysm repair. A systematic search of the literature published until January 2024 was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses of Diagnostic Test Accuracy (PRISMA-DTA) guidelines. The pooled rates of sensitivity, specificity, and diagnostic odds ratio of MVUS in endoleak detection with computed tomography angiography as the reference standard were estimated using univariate random-effect analysis with 95% confidence intervals. Three studies were considered eligible for inclusion. Superb micro-vascular imaging (SMI) was used as an MVUS technique in all cases. The total number of paired scans was 209. Sensitivity and specificity of the individual studies ranged 0.75-1.00 and 0.93-1.00, respectively. Pooled sensitivity and specificity of the SMI method was 0.91 (CI: 0.82-0.96) and 0.98 (CI: 0.94-1.00), respectively. The pooled diagnostic odds ratio was 635 (95% CI: 128-3140). The findings of the present study support the use of the MVUS for endoleak detection. However, further research is warranted to explore the broader application of MVUS, providing a more comprehensive understanding and establishing robust criteria for its role in clinical practice.

Tea polyphenol nanoparticles enable targeted siRNA delivery and multi-bioactive therapy for abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease, while there is a lack of pharmaceutical interventions to halt AAA progression presently. To address the multifaceted pathology of AAA, this work develops a novel multifunctional gene delivery system to simultaneously deliver two siRNAs targeting MMP-2 and MMP-9. The system (TPNs-siRNA), formed through the oxidative polymerization and self-assembly of epigallocatechin gallate (EGCG), efficiently encapsulates siRNAs during self-assembly. TPNs-siRNA safeguards siRNAs from biological degradation, facilitates intracellular siRNA transfection, promotes lysosomal escape, and releases siRNAs to silence MMP-2 and MMP-9. Additionally, TPNs, serving as a multi-bioactive material, mitigates oxidative stress and inflammation, fosters M1-to-M2 repolarization of macrophages, and inhibits cell calcification and apoptosis. In experiments with AAA mice, TPNs-siRNA accumulated and persisted in aneurysmal tissue after intravenous delivery, demonstrating that TPNs-siRNA can be significantly distributed in macrophages and VSMCs relevant to AAA pathogenesis. Leveraging the carrier's intrinsic multi-bioactive properties, the targeted siRNA delivery by TPNs exhibits a synergistic effect for enhanced AAA therapy. Furthermore, TPNs-siRNA is gradually metabolized and excreted from the body, resulting in excellent biocompatibility. Consequently, TPNs emerges as a promising multi-bioactive nanotherapy and a targeted delivery nanocarrier for effective AAA therapy.

Preemptive treatment of type II endoleak for abdominal aortic aneurysm with renal fusion (horseshoe kidney)

OBJECTIVE

To assess viability and safety of preemptive treatment of type II endoleak for abdominal aortic aneurysm (AAA) repairs.

METHODS

A 69-year-old man with renal fusion (horseshoe kidney) was referred for treatment of a 5.5 cm AAA. His anatomy was suitable for endovascular repair. The risk for type II endoleak was increased because of multiple infrarenal arterial orifices originating within the aneurysm sac. These included an accessory renal artery that supplied the renal isthmus, a patent inferior mesenteric artery, and a pair of large lumbar arteries originating from a single orifice (8 mm) at L3 spinal level. The lumbar orifice was selectively cannulated and occluded with thrombogenic coils 1 week prior to his endovascular aneurysm repair.

RESULTS

Aneurysm repair was uneventful with no signs of early or delayed endoleak and long-term follow-up of 5 years.

CONCLUSIONS

Preemptive coil embolization of perianeurysmal arteries may be considered as a safe and effective strategy for management of potential type II endoleak.

CO2 Angiography in the Standard and Complex Endovascular Repair of the Abdominal Aorta-A Narrative Review of the Literature

Background/Objectives: Carbon dioxide digital-subtraction angiography (CO2-DSA) is an increasingly adopted technique in endovascular aortic repair (EVAR) and fenestrated/branched EVAR (F/B-EVAR); it is used to reduce the amount of iodinate contrast medium (ICM) and prevent postoperative renal function worsening (PO-RFW). Our aim is to report results from the literature on EVAR and F/B-EVAR procedures using CO2-DSA, together with wider applications in aortic endovascular treatment. Methods: We performed a literature review by searching electronic databases for published data on CO2-DSA during EVAR and F/B-EVAR procedures. The endpoints were postoperative renal function worsening (PO-RFW) and efficacy of intraoperative arterial visualization. Further, applications of CO2 for thoracic endovascular aortic repair (TEVAR) were described. Results: Seventeen studies reporting results on CO2-DSA in EVAR (644 patients) were retrieved. Overall, 372 (58%) procedures were performed with CO2 alone, and 272 (42%) were performed with CO2+ICM. Eight studies analyzed the effect of CO2-DSA angiography on PO-RFW; four studies showed a significantly lower rate of PO-RFW compared to ICM. Five studies (153 patients) analyzed intraoperative arterial visualization with CO2-DSA; renal and hypogastric arteries were effectively visualized in 69% and 99% of cases, respectively. The use of CO2-DSA in F/B-EVAR has not been widely investigated. The largest series reported that PO-RFW was lower in the CO2 vs. ICM group. Conclusions: Carbon dioxide is widely applied in modern aortic endovascular treatment. CO2-DSA for EVAR and F/B-EVAR is an efficient technique for reducing PO-RFW while allowing acceptable arterial intraoperative visualization.

Editor's Choice - Outcomes Following Intact and Ruptured Aneurysm Repair across Nations: Analysis of International Registry Data from the VASCUNET Collaboration 2014 - 2019

OBJECTIVE

To determine the peri-operative mortality rate for intact and ruptured abdominal aortic aneurysm (AAA) repair in 10 countries and to compare practice and outcomes over a six year period by age, sex, and geographic location.

METHODS

This VASCUNET study used prospectively collected data from vascular registries in 10 countries on primary repair of intact and ruptured AAAs undertaken between January 2014 and December 2019. The primary outcome was peri-operative death (30 day or in hospital). Logistic regression models were used to estimate the association between peri-operative death, patient characteristics, and type of procedure. Factors associated with the use of endovascular aortic aneurysm repair (EVAR) were also evaluated.

RESULTS

The analysis included 50 642 intact and 9 453 ruptured AAA repairs. The proportion of EVARs for intact repairs increased from 63.4% in 2014 to 67.3% in 2016 before falling to 62.3% in 2019 (p < .001), but practice varied between countries. EVAR procedures were more common among older patients (p < .001) and men (p < .001). Overall peri-operative mortality after intact AAA repair was 1.4% (95% confidence interval [CI] 1.3 - 1.5%) and did not change over time. Mortality rates were stable within countries. Among ruptured AAA repairs, the proportion of EVARs increased from 23.7% in 2014 to 35.2% in 2019 (p < .001). The average aortic diameter was 7.8 cm for men and 7.0 cm for women (p < .001). The overall peri-operative mortality rate was 31.3% (95% CI 30.4 - 32.2%); the rates were 36.0% (95% CI 34.9 - 37.2%) for open repair and 19.7% (95% CI 18.2 - 21.3%) for EVAR. This difference and shift to EVAR reduced peri-operative mortality from 32.6% (in 2014) to 28.7% (in 2019).

CONCLUSION

The international practice of intact AAA repair was associated with low mortality rates in registry reported data. There remains variation in the use of EVAR for intact AAAs across countries. Overall peri-operative mortality remains high after ruptured AAA, but an increased use of EVAR has reduced rates over time.

Center-level outcomes following elective fenestrated endovascular aortic aneurysm repair in the Vascular Quality Initiative database

OBJECTIVE

Hospital volume is associated with mortality after open aortic aneurysm repair. Fenestrated and branched endovascular aortic repair (B-FEVAR) has been increasingly used for repair of complex thoracoabdominal and juxtarenal aneurysms, but evidence of a center-volume relationship is limited. We aimed to measure the association of center volume with in-hospital mortality, postoperative outcomes, and 1-year survival following B-FEVAR.

METHODS

Patients undergoing elective endovascular thoracoabdominal and complex abdominal aneurysm repair with branch intervention (2014-2021) listed within the national Vascular Quality Initiative Thoracic Endovascular Aortic Repair/Complex EVAR database were analyzed. Centers were grouped into quartiles by mean annual procedure volume. Multivariable regression was used to evaluate the effect of center volume on in-hospital mortality adjusting for baseline and procedural characteristics. Kaplan-Meier estimation, log rank test, and mixed effects Cox regression were used to evaluate 1-year survival.

RESULTS

A total of 4302 adult elective F-BEVAR procedures were identified at a total of 163 centers. In-hospital mortality did not differ by hospital volume (quartile [Q]1 = 35/1059 [3.3%]; Q2 = 30/1063 [2.8%]; Q3 = 33/1120 [2.9%]; and Q4 = 44/1060 [4.2%]; P = .308). The high volume group had a higher rate of major complication (Q1 = 14.9%; Q2 = 12.8%; Q3 = 13.3%; and Q4 = 20.1%; adjusted P < .001). Physician-modified grafts were more frequently employed in high-volume centers (Q1 = 4.5%; Q2 = 18.7%; Q3 = 11.3%; and Q4 = 19.2%; P < .001), with a decreased incidence of any endoleak noted at the end of the procedure (Q1 = 34.9%; Q2 = 32.8%; Q3 = 30.0%; and Q4 = 29.0%; P = .003). In the multivariable analysis, in-hospital mortality was not associated with center volume, comparing very low volume to medium- and high-volume centers (odds ratio [95% confidence interval] vs Q4: Q1 = 1.1 [0.6-1.9], Q2 = 0.6 [0.4-1.1], and Q3 = 0.9 [0.5-1.5]; all P > .05). No significant difference was found in 1-year survival between center volume groups.

CONCLUSIONS

In-hospital mortality is not associated with procedure volume within centers performing complex endovascular aortic repair. However, complication rates and endoleak may be associated with procedure volume. Long-term outcomes by annualized procedure volume, specifically graft durability and sac expansion, should be investigated.

The Role of Integrated Air Transport System in Managing Patients with Abdominal Aortic Aneurysm Rupture

OBJECTIVE

Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising specialty care to quaternary referral centres. The association between travel distance by air ambulance and rAAA mortality in patients transferred as an emergency for repair was examined.

METHODS

A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at an OSH for continued critical care were excluded. Patients were divided into near and far groups based on the 75th percentile of the straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariable logistic regression was used to assess the association between distance and mortality after adjusting for age, sex, ethnicity, cardiovascular comorbidities, and repair type.

RESULTS

A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both the near and far groups had similar ages, sex, and ethnicity. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon use were also similar. Neither the observed (26.8% vs. 23.9%, p = .61) nor the adjusted odds ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality rate differed significantly between the near and far groups.

CONCLUSION

Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

A Dual-Targeting, Multi-Faceted Biocompatible Nanodrug Optimizes the Microenvironment to Ameliorate Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a highly lethal cardiovascular disease that currently lacks effective pharmacological treatment given the complex pathophysiology of the disease. Here, single-cell RNA-sequencing data from patients with AAA and a mouse model are analyzed, which reveals pivotal pathological changes, including the M1-like polarization of macrophages and the loss of contractile function in smooth muscle cells (SMCs). Both cell types express the integrin αvβ3, allowing for their dual targeting with a single rationally designed molecule. To this end, a biocompatible nanodrug, which is termed EVMS@R-HNC, that consists of the multifunctional drug everolimus (EVMS) encapsulated by the hepatitis B virus core protein modifies to contain the RGD sequence to specifically bind to integrin αvβ3 is designed. Both in vitro and in vivo results show that EVMS@R-HNC can target macrophages as well as SMCs. Upon binding of the nanodrug, the EVMS is released intracellularly where it exhibits multiple functions, including inhibiting M1 macrophage polarization, thereby suppressing the self-propagating inflammatory cascade and immune microenvironment imbalance, while preserving the normal contractile function of SMCs. Collectively, these results suggest that EVMS@R-HNC presents a highly promising therapeutic approach for the management of AAA.

Sex Influence on Fenestrated and Branched Endovascular Aortic Aneurysm Repair: Outcomes From a National Multicenter Registry

INTRODUCTION

Women are generally underrepresented in trials focusing on aortic aneurysm. Nevertheless, sex-related differences have recently emerged from several studies and registries. The aim of this research was to assess whether sex-related anatomical disparities existed in fenestrated and branched aortic repair candidates and whether these discrepancies could influence endovascular repair outcomes.

METHODS

Data from all consecutive patients treated during the 2008-2019 period within the Italian Multicenter fenestrated or branched endovascular aortic repair (F/BEVAR) Registry were included in the present study. Propensity matching was performed using a logistic regression model adjusted for demographic data and comorbidities to obtain comparable male and female samples. The selection model led to a final study population of 176 patients (88 women and 88 men) among the total initial cohort of 596. Study endpoints were technical and clinical success, overall survival, aneurysm-related death, and reintervention rates evaluated at 30 days and during follow-up.

RESULTS

Twenty-eight patients (15.9%) received urgent/emergent repair. In most of the cases (71.6%), women received treatment for extensive thoracoabdominal pathology (Crawford type I, II, or III aneurysm rather than type IV or juxta-pararenal) versus 46.6% of men (p=0.001). Female patients presented with more challenging iliac accesses with at least one side considered hostile in 27.3% of the cases (vs 13.6% in male patients, p=0.039). Finally, women had significantly smaller visceral vessels. Women had significantly worse operative outcomes, with an 86.2% technical success rate versus 96.6% in the male population (p=0.016). No differences were recorded in terms of 30-day reinterventions between men and women. The 5-year estimate of freedom from late reintervention, according to Kaplan-Meier analysis, was 85.6% in men versus 81.6% in women (p=ns). No aneurysm-related death was recorded during follow-up (median observational time, 23 months [interquartile range, 7-45 months]).

CONCLUSION

Women presented a significantly higher incidence of thoracoabdominal aneurysms, smaller visceral vessels, and more complex iliofemoral accesses, resulting in a significantly lower technical success after F/BEVAR. Further studies assessing sex-related differences are needed to properly determine the impact on outcomes and stratify procedural risks.

CLINICAL IMPACT

Women are generally underrepresented in trials focusing on aortic aneurysms. Aiming to assess whether sex may affect outcomes after a complex endovascular aortic repair, a propensity score selection was applied to a total population of 596 patients receiving F/BEVAR aortic repair with the Cook platform, matching each treated female patient with a corresponding male patient. Women presented more frequently a thoracoabdominal aneurysm extent, smaller visceral vessels, and complex iliofemoral accesses, resulting in significantly worse operative outcomes, with an 86.2% technical success versus 96.6% (p=0.016). No differences were recorded in terms of short-term and mid-term reinterventions. According to these results, careful and critical assessment should be posed in case of female patients receiving complex aortic repair, especially regarding preoperative anatomical evaluation and clinical selection with appropriate surgical risk stratification.

Ten-year single-center outcomes following endovascular repair for abdominal aortic aneurysm using the INCRAFT device

OBJECTIVE

This study aimed to report the long-term outcomes beyond 10 years of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms using the low-profile INCRAFT device.

METHODS

This was a single-center, retrospective cohort study of all patients undergoing EVAR using the INCRAFT device as part of the regulatory trial between 2012 and 2013. Primary endpoint was aneurysm-related death. Secondary endpoints were all-cause death, reintervention, late open conversion, and aneurysm status (shrinkage, stable, and growth).

RESULTS

Thirty patients with a mean age of 71.8 ± 7.7 years were included in this study. The median aneurysm diameter at EVAR was 54.5 mm (interquartile range, 53-56.8 mm). All abdominal aortic aneurysms in this study were treated following the device's instructions for use. At index EVAR, the INCRAFT device was successfully implanted in all patients using a percutaneous approach under local anesthesia. No patients experienced major adverse events or procedure-related complications 30 days after EVAR. During the median follow-up of 125 months (interquartile range, 98-131 months) with follow-up rates of 100% at 5 years and 96.7% at 10 years, aneurysm-related mortality was 0%, and freedom from all-cause mortality was 82.9% at 5 years and 75.3% at 10 years. Reintervention was required in 10 patients with 15 procedures. Sac growth was observed in 11 patients (36.7%), six of whom eventually required late open conversion; five of these patients underwent open aneurysmorrhaphy with stent graft preservation, and one underwent open surgical repair with endograft explantation. Late rupture was identified in one case, where type Ia endoleak led to rupture at 69 months, and open repair was successfully performed. Freedom from reintervention was 89.0% at 5 years but declined to 60.9% at 10 years; freedom from late open conversion was 100% at 5 years but declined to 70.8% at 10 years.

CONCLUSIONS

Long-term outcomes of the INCRAFT stent graft showed no aneurysm-related deaths. However, sac growth occurred persistently throughout the follow-up period, resulting in a relatively high rate of reinterventions in the later periods, which highlights the importance of lifelong postoperative surveillance and appropriate reinterventions when indicated.

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.

Systematic Review Examining the Association Between Angiotensin Converting Enzyme Inhibitor or Angiotensin Receptor Blocker Prescription and Abdominal Aortic Aneurysm Growth and Events

OBJECTIVE

Whether angiotensin II blockade is an effective medical treatment for abdominal aortic aneurysms (AAAs) has not been established. This systematic review and meta-analysis aimed to determine the association between angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) prescription and AAA growth and events.

DATA SOURCES

MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library databases were searched from their inception to 4 January 2024, with no language restrictions.

REVIEW METHODS

The five databases were searched for randomised controlled trials (RCTs) and observational studies reporting the association between ACEi or ARB prescription and AAA growth, repair, or rupture. The primary outcome was AAA growth, with secondary outcomes of AAA rupture, AAA repair, and AAA related events (rupture and repair combined). Risk of bias was assessed using the Risk of Bias 2 tool for RCTs and with a modified Newcastle-Ottawa scale for observational studies. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Random effects models were used for meta-analyses.

RESULTS

Eleven studies (two RCTs, eight observational studies, and one meta-analysis of individual patient data from seven populations) involving 58 022 patients were included. ACEi prescription was not associated with a statistically significant reduction in AAA growth (standard mean difference 0.01 mm/year, 95% confidence interval [CI] -0.26 - 0.28; p = .93; I2 = 98%) or AAA repair (odds ratio [OR] 0.73, 95% CI 0.50 - 1.09; p = .65; I2 = 61%), but was associated with a statistically significantly lower risk of AAA rupture (OR 0.87, 95% CI 0.81 - 0.93; p < .001; I2 = 26%) and AAA related events (OR 0.82, 95% CI 0.72 - 0.95; p = .006; I2 = 80%). ARB prescription was not associated with significantly reduced AAA growth or a lower risk of AAA related events. The two RCTs had a low risk of bias, with one observational study having low, seven moderate, and one high risk of bias. All of the findings had a very low certainty of evidence based on the GRADE analysis.

CONCLUSION

There was no association between ACEi or ARB prescription and AAA growth, but ACEi prescription was associated with a reduced risk of AAA rupture and AAA related events with very low certainty of evidence.

Risk factors of type 1A endoleak following endovascular aortic aneurysm repair

OBJECTIVES

Endovascular repair of infrarenal aortic aneurysms are the treatment of first choice. However, the proximal sealing of endovascular aneurysm repair is the Achilles' heel of the procedure. Insufficient proximal sealing can lead to endoleak type 1A and therefore expansion of the aneurysm sack and subsequent rupture.

METHODS

We performed a retrospective analysis of all consecutive patients with an infrarenal abdominal aneurysm treated with endovascular aneurysm repair. We studied whether demographic and anatomical features were risk factors for endoleak type 1A. Also, the results of different treatment strategies were described.

RESULTS

257 Patients were included in the study, most patients were male. In the multivariate analysis, female gender and infrarenal angulation were the most important risk factors for endoleak type 1A. Endoleak type 1A diagnosed at completion angiography disappeared in 77.8%. The occurrence of endoleak type 1A was associated with a higher risk of aneurysm-related mortality (p = 0.01).

CONCLUSION

Conclusions should be drawn with care, since the number of patients included in this study was small and there was a high incidence of patients lost to follow-up. This study suggests that endovascular aneurysm repair in female patients and patients with severe infrarenal angulation is associated with a higher risk of endoleak type 1A.