Endovascular grafts for abdominal aortic aneurysm

Outcome Analysis of Speed Gate Cannulation during Standard Infrarenal Endovascular Aneurysm Repair

BACKGROUND

Endovascular aortic repair (EVAR) is generally performed with bi/trimodular stent-grafts requiring retrograde contralateral gate cannulation (CGC). In the case of tricky CGC, an increased EVAR procedural time and radiation exposure have been reported. Herein, we compare the outcomes of conventional CGC and CGC using the speed gate cannulation (SGC) technique in standard EVAR for a propensity-matched cohort.

METHODS

A total of 371 patients were retrospectively analyzed. Inclusion criteria were fulfilled in 172 patients who underwent propensity score matching. Primary outcomes included operative time, CGC time, mean contrast medium, fluoroscopy time, and CGC fluoroscopy time.

RESULTS

After matching, 78 patients were included in each group (SGC vs. standard). Primary outcomes registered a significant reduction in CGC time (4 [1-6] vs. 8 [6-14] min; p = 0.001) and fluoroscopy time (12 [9-16] vs. 17 [12-25] min).

CONCLUSIONS

In this preliminary experiment, the use of SGC was feasible with no significant registered postoperative complications. A significant reduction in contrast medium usage, radiation exposure, and CGC time was observed with the use of SGC. SGC is a simple adjunctive technique, and its use should be considered in standard EVAR, especially in emergency scenarios, where time is of the essence.

A radiomics model for predicting the outcome of endovascular abdominal aortic aneurysm repair based on machine learning

OBJECTIVE

This study aimed to develop a radiomics model to predict the outcome of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA), based on machine learning (ML) algorithms.

METHODS

We retrospectively reviewed 711 patients with infra-renal AAA who underwent elective EVAR procedures between January 2016 and December 2019 at our single center. The radiomics features of AAA were extracted using Pyradiomics. Pearson correlation analysis, analysis of variance (ANOVA), least absolute shrinkage, and selection operator (LASSO) regression were applied to determine the predictors for EVAR-related severe adverse events (SAEs). Eighty percent of patients were classified as the training set and the remaining 20 percent of patients were classified as the test set. The selected features were used to build a radiomics model in training set using different ML algorithms. The performance of each model was assessed using the area under the curve (AUC) from the receiver operating characteristic (ROC) curve in the test set.

RESULTS

A total of 493 patients were enrolled in this study, the mean follow-up time was 32 months. During the follow-up, 156 (31.6%) patients experienced EVAR-related SAEs. A total of 1223 radiomics features were extracted from each patient, of which 30 radiomics features were finally identified. The quantitative performance assessment and the ROC curves indicated that the logistics regression (LR) model had better predictive value than others, with accuracy, 0.86; AUC, 0.93; and F1 score, 0.91. The Rad-score waterfall plot showed that the overall amount of error was small both in the training set and in the test set. Calibration curve showed that the calibration degree of the training set and the test set were good (p > 0.05). Decision curve analysis (threshold 0.32) demonstrated that the model had good clinical applicability.

CONCLUSION

Our radiomics model could be used as an efficient and adjunctive tool to predict the outcome after EVAR.

Long Term Outcomes and Potential Risk Factors for Endovascular Repair of Aortic Pseudoaneurysms in Vascular Behçet's Disease

OBJECTIVE

This study aimed to analyse long term outcomes and risk factors for endovascular repair of aortic pseudoaneurysms in patients with vascular Behçet's disease (BD).

METHODS

Medical records of 26 aortic vascular BD patients who underwent endovascular treatment at the vascular department of Peking Union Medical College Hospital between January 2002 and December 2021 were reviewed retrospectively. Erythrocyte sedimentation rate (ESR) and C reactive protein were used to assess BD activity. Computed tomography angiography (CTA) was obtained pre- and post-operatively for almost all patients. Univariable logistic regression analysis was used to analyse risk factors for endovascular repair, such as inflammatory indicators, drug usage, and stent graft parameters.

RESULTS

The abdominal aorta (n = 17) was the most common site of 27 vascular BD pseudoaneurysms in this study. CTA also revealed one aortic arch pseudoaneurysm, seven descending thoracic aortic pseudoaneurysms, one thoraco-abdominal aortic pseudoaneurysm, and one pseudoaneurysm at the aortic bifurcation. Most of the pseudoaneurysms were treated with covered stent grafts. The technical success rate was 96% and no deaths occurred during hospital stay. The mean follow up was 5.8 ± 5.5 years and 31% (8/26) experienced post-operative complications. Overall one, three, and five year event free survival rates were 87%, 78%, and 74%, respectively. Univariable logistic regression analysis revealed that pre-operative ESR ≥ 16.0 mm/h (p = .040), pre-operative glucocorticoid (GC) use ≤ 11.5 days (p = .024), pre-operative immunosuppressant use ≤ 15.5 days (p = .028), and length of proximal landing zone ≤ 1.95 cm (p = .034) were associated with a worse prognoses following endovascular treatment. Proximal oversize ≥ 9.5% (p = .074) was also regarded as a risk factor, although not statistically significant.

CONCLUSION

This study further confirmed the feasibility of endovascular repair for aortic vascular BD patients. Risk factors predicting poor prognoses included elevated pre-operative ESR, insufficient pre-operative GC use or immunosuppressant use, inadequate proximal landing zone, and larger proximal oversize percentage.

PCSK9, a novel immune and ferroptosis related gene in abdominal aortic aneurysm neck

The gene expression profile of abdominal aortic aneurysm (AAA) neck is not fully understood. The etiology of AAA is considered to be related to atherosclerosis and the inflammatory response, involving congenital, genetic, metabolic, and other factors. The level of proprotein convertase subtilisin/kexin type 9 (PCSK9) is related to those of cholesterol, oxidized low-density lipoprotein, and triglycerides. PCSK9 inhibitors have significant effects on lowering LDL-cholesterol, reversing atherosclerotic plaques, and reducing the risk of cardiovascular events and have been approved by several lipid-lowering guidelines. This work was aimed to investigate the potential role of PCSK9 in the neck of AAA. We extracted the expression dataset (GSE47472) containing 14 AAA patients and 8 donors and single-cell RNAseq (scRNA-seq) data (GSE164678) of CaCl2-induced (AAA) samples from the Gene Expression Omnibus dataset. Through bioinformatics methods, we found that PCSK9 was up-regulated in the proximal neck of human AAA. In AAA, PCSK9 was mainly expressed in fibroblasts. Additionally, immune check-point PDCD1LG2 was also expressed higher in AAA neck than donor, while CTLA4, PDCD1, and SIGLEC15 were down-regulated in AAA neck. The expression of PCSK was correlated with PDCD1LG2, LAG3, and CTLA4 in AAA neck. Additionally, some ferroptosis-related genes were also down-regulated in AAA neck. PCSK9 was also correlated with ferroptosis-related genes in AAA neck. In conclusion, PCSK9 was highly expressed in AAA neck, and may exert its role through interacting with immune check-points and ferroptosis-related genes.

Tricaprin can prevent the development of AAA by attenuating aortic degeneration

Medical therapeutic options to prevent rupture of abdominal aortic aneurysm (AAA), a critical event, must be developed. Moreover, further understanding of the process of AAA development and rupture is crucial. Previous studies have revealed that aortic hypoperfusion can induce the development of AAA, and we successfully developed a hypoperfusion-induced AAA animal model. In this study, we examined the effects of medium-chain triglycerides (MCTs), tricaprylin (C8-TG) and tricaprin (C10-TG), on hypoperfusion-induced AAA rat model. We estimated the effects of MCTs on aortic pathologies, mechanical properties of the aorta, and development of AAA. C10-TG, but not C8-TG, significantly suppressed AAA development and completely prevented the rupture. We observed that C10-TG prevented the development and rupture of AAA, but not C8-TG. Additionally, regression of AAA diameter was observed in the C10-TG group. Pathological analysis revealed C10-TG improved the hypoperfusion-induced increase in hypoxia-inducible factor-1α levels, medial smooth muscle cells (SMCs) loss, degeneration of aortic elastin and collagen fibers, and loss of aortic wall elasticity. In addition, regression of the formed AAA was observed by administration of C10-TG after AAA formation. C10-TG administration after AAA formation improved degeneration of AAA wall including degradation of aortic elastin and collagen fibers, stenosis of vasa vasorum, and loss of medial SMCs. These data suggest C10-TG can prevent AAA by attenuating aortic hypoperfusion and degeneration. Considering the clinical safety of C10-TG, C10-TG can be a promising AAA drug candidate.

Development and Comparison of Multimodal Models for Preoperative Prediction of Outcomes After Endovascular Aneurysm Repair

Objective

The aim of this study was to develop and compare multimodal models for predicting outcomes after endovascular abdominal aortic aneurysm repair (EVAR) based on morphological, deep learning (DL), and radiomic features.

Methods

We retrospectively reviewed 979 patients (January 2010—December 2019) with infrarenal abdominal aortic aneurysms (AAAs) who underwent elective EVAR procedures. A total of 486 patients (January 2010–December 2015) were used for morphological feature model development and optimization. Univariable and multivariable analyses were conducted to determine significant morphological features of EVAR-related severe adverse events (SAEs) and to build a morphological feature model based on different machine learning algorithms. Subsequently, to develop the morphological feature model more easily and better compare with other modal models, 340 patients of AAA with intraluminal thrombosis (ILT) were used for automatic segmentation of ILT based on deep convolutional neural networks (DCNNs). Notably, 493 patients (January 2016–December 2019) were used for the development and comparison of multimodal models (optimized morphological feature, DL, and radiomic models). Of note, 80% of patients were classified as the training set and 20% of patients were classified as the test set. The area under the curve (AUC) was used to evaluate the predictive abilities of different modal models.

Results

The mean age of the patients was 69.9 years, the mean follow-up was 54 months, and 307 (31.4%) patients experienced SAEs. Statistical analysis revealed that short neck, angulated neck, conical neck, ILT, ILT percentage ≥51.6%, luminal calcification, double iliac sign, and common iliac artery index ≥1.255 were associated with SAEs. The morphological feature model based on the support vector machine had a better predictive performance with an AUC of 0.76, an accuracy of 0.76, and an F1 score of 0.82. Our DCNN model achieved a mean intersection over union score of more than 90.78% for the segmentation of ILT and AAA aortic lumen. The multimodal model result showed that the radiomic model based on logistics regression had better predictive performance (AUC 0.93, accuracy 0.86, and F1 score 0.91) than the optimized morphological feature model (AUC 0.62, accuracy 0.69, and F1 score 0.81) and the DL model (AUC 0.82, accuracy 0.85, and F1 score 0.89).

Conclusion

The radiomic model has better predictive performance for patient status after EVAR. The morphological feature model and DL model have their own advantages and could also be used to predict outcomes after EVAR.

The Incraft stent graft for the treatment of abdominal aortic aneurysms: an iliac-friendly device with an effective conventional proximal sealing mechanism

INTRODUCTION

The Incraft aortic stent graft (Cordis, Bridgewater, NJ, USA) is a trimodular endovascular stent graft with a conventional suprarenal active fixation specifically designed to overcome the anatomic limitation of small, stenotic, and tortuous iliac vessels.

AREAS COVERED

The present article provides a complete description of the Incraft stent graft, its clinical performance, its technical characteristics as well as a comparison with other competitive endografts.

EXPERT OPINION

The Incraft stent graft is an EVAR ultra low-profile device initially designed for overcoming the limitation of the hostile iliac anatomy. Recently, the device is being increasingly used in real-world conditions and not only in complex iliac anatomies with good mid-term results. Whether it remains a useful EVAR toolbox or will become a workhorse endograft is yet to be determined.

Is percutaneous access superior to cutdown access for endovascular abdominal aortic aneurysm repair? A meta-analysis

OBJECTIVE

The objective is to investigate whether percutaneous access (pEVAR) is superior to cutdown access (cEVAR) in terms of safety and efficacy during endovascular repair of abdominal aortic aneurysms (AAAs).

METHODS

We searched PubMed, Embase, and Cochrane Library from January 1999 to December 2020 for studies reporting on the comparison between percutaneous and cutdown techniques for endovascular repair of AAAs. Outcomes evaluated were technical success rates, access site-related complications and operative time, and hospital stay.

RESULTS

Four randomized controlled trials and nine observational studies with a total of 1683 patients comprising 2715 groin accesses were eligible for the meta-analysis. pEVAR was associated with a lower risk of overall complications (odds ratio (OR) = 0.63; p = .005) and seroma/lymphorrhea (OR, 0.18; p = .0001) and shortened operation time (MD = -39.04; p = .002) and the length of hospital stay (MD = -0.75; p < .00001) compared with cEVAR. The technical success rate for pEVAR was 95.1% (694/729), with an overall OR of 0.27 (95% CI 0.14-0.55, p = .0003) comparing pEVAR with cEVAR. Furthermore, pEVAR did not increase the risk of site infection, femoral artery thrombosis, postoperative hematoma, nerve injury, dissection, and bleeding.

CONCLUSION

Percutaneous endovascular aneurysm repair is a safe and effective method for the treatment of AAA. It reduces the risk of overall complications and shortens the operation time and hospital stay. The technical success rate of pEVAR is lower than that of cEVAR, which may be linked to the selection of patients, operator experience, and the use of ultrasound. Large definitive trials are required to draw robust conclusions.

LncRNA SENCR suppresses abdominal aortic aneurysm formation by inhibiting smooth muscle cells apoptosis and extracellular matrix degradation

Abdominal aortic aneurysm (AAA) is a progressive chronic dilatation of the abdominal aorta without effective medical treatment. This study aims to clarify the potential of long non-coding RNA SENCR as a treatment target in AAA. Angiotensin II (Ang-II) was used to establish AAA model in vitro and in vivo. Reverse transcription quantitative PCR and western blot were performed to measure the expression of SENCR and proteins, respectively. Annexin V-FITC/PI double staining was carried out to detect the apoptotic rate in vascular smooth muscle cells (VSMCs), and cell apoptosis in aortic tissues was determined by TUNEL staining. Besides, hematoxylin and eosin and Elastica van Gieson staining were performed for histological analysis of aortic tissues. SENCR was downregulated in AAA tissues and Ang-II-stimulated VSMCs. Overexpression of SENCR could inhibit Ang-II-induced VSMC apoptosis, while inhibition of SENCR facilitated Ang-II-induced VSMC apoptosis. Moreover, the expression of matrix metalloproteinase (MMP)-2 and MMP-9 in Ang-II-induced VSMCs was reduced following SENCR overexpression, while tissue inhibitor of metalloproteinases 1 (TIMP-1) expression was increased. In vivo, overexpression of SENCR improved the pathological change in aortic tissues and the damage in arterial wall elastic fibers induced by Ang-II, as well as suppressed Ang-II-induced cell apoptosis and extracellular matrix degradation. Overall, SENCR was decreased in AAA. Overexpression of SENCR inhibited AAA formation via inhibition of VSMC apoptosis and extracellular matrix degradation. We provided a reliable evidence for SENCR acting as a potential target for AAA treatment.

Histologic Analysis with the Newly Designed Exoskeleton Seal® Stent-Graft in the Porcine Abdominal Aorta

PURPOSE

To investigate the technical feasibility of a novel exoskeleton Seal^® stent-graft and analyze early histologic changes in the porcine abdominal aorta.

MATERIALS AND METHODS

Six pigs received an abdominal stent-graft (Group I), and six received an iliac branch stent-graft (Group II). Groups were subdivided as follows: Group Ia, which received three bifurcated main-body stent-grafts; Group Ib, which received three bifurcated main-body stent-grafts with both iliac graft-stents; Group IIa, which received three simple uni-iliac tapered stent-grafts; and Group IIb, which received three uni-iliac tapered tapered stent-grafts with right straight limb and left branched limb. Statistical analyses were performed with the Wilcoxon signed-rank test and mixed-model regression analysis.

RESULTS

The primary technical success rate (< 24 h) was 83% because of two acute thromboses in the lumen of the stented abdominal aorta immediately after stent-graft placement. At 4 weeks, late thrombosis occurred in two pigs. Higher mean neointimal hyperplasia areas (23.5% vs. 16.2%; P = .047), neointimal hyperplasia thicknesses (545.5 μm vs. 422.2 μm; P = .001), and degrees of collagen deposition (2.71 vs. 2.33; P = .002) were observed at the bare-metal stent-graft compared with the proximal exoskeleton portion of the stent-graft, with no significant differences between the patent and occluded groups or among the four types of stent-grafts.

CONCLUSIONS

The exoskeleton stent-graft demonstrates 66% of patency rate during 1-month follow-up due to four cases of thromboses; however, the endothelialization on the junction of proximal graft showed no significant differences between the patent and occluded groups. Further studies should investigate long-term outcomes with prolonged neointimal hyperplasia.

Peripheral artery disease is associated with poor clinical outcome in patients with abdominal aortic aneurysm after endovascular aneurysm repair

BACKGROUND

We investigated the effects of coronary artery disease (CAD) or peripheral artery disease (PAD) on clinical outcomes of patients with abdominal aortic aneurysm (AAA) treated with endovascular aortic aneurysm repair (EVAR).

METHODS

We retrospectively evaluated a total of 475 patients with AAA treated with EVAR at a single center. Patients were divided into three groups: group A (n = 166), patients without CAD or PAD; group B (n = 196), patients with CAD but without PAD; and group C (n = 113), patients with PAD regardless of CAD. The primary endpoint was the accumulated rate of major adverse cardiovascular and cerebrovascular event (MACCE), a composite of all-cause death, myocardial infarction (MI), or stroke.

RESULTS

The prevalence of CAD and PAD in patients with AAA was 55.8 and 23.8%, respectively. Patients were followed for 40.2 ± 35.3 months. Baseline characteristics were similar among the groups except for current smoking (A, 27.4%; B, 20.8%; C, 50.5%; p = 0.001). Three years after EVAR, the incidences of MACCE (A, 5.6%; B, 9.5%; C, 16.7%; p = 0.021) and stroke (A, 0%; B, 2.2%; C, 5.2%; p = 0.025) were highest in group C. All-cause death and aneurysm death did not differ among the groups. PAD [hazard ratio (HR) 2.88, 95% confidence interval (CI) 1.32-6.29, p = 0.008] and previous stroke (HR 4.39, 95% CI 1.94-9.93, p < 0.001) were independent predictors of MACCE.

CONCLUSIONS

PAD was an independent risk factor of increased MACCE and stroke for patients with AAA undergoing EVAR. More intensive secondary prevention may be needed to reduce adverse cardiovascular events in AAA patients with PAD.

Trends in endovascular aneurysm repair research: bibliometric analysis from 1994 to 2017

PURPOSE

Since endovascular aneurysm repair (EVAR) was first introduced in 1991, it has undergone rapid technical and quantitative developments. We analyzed the characteristics and trends of EVAR research through bibliometric analysis.

METHODS

Comprehensive online searches focused on EVAR were performed from January 1994 to August 2017. The following information was collected: title, year of publication, countries' contribution, authorship, subspecialty, institution, subject category, and top 10 cited articles.

RESULTS

A significant increase was demonstrated globally in the number of annual publications on EVAR. The highest number of publications was from the United States (n = 849, 35.08%), followed by England (n = 343, 14.17%), and the institutions with highest number of publications were Stanford University (n = 61, 2.52%) and Skane University Hospital Malmo (n = 45, 1.86%). The Journal of Vascular Surgery published approximately one quarter of the total publications. Vascular surgeons produced the most publications (n = 1871, 78.14%), followed by radiologists (n = 377, 15.58%) and cardiologists (n = 73, 3.02%). The most studied topics on EVAR were complications and procedures. The number of publications on complex EVAR and EVAR in juxtarenal aneurysm has increased more from 2013 to 2017 (5.1%, 9.5%) compared with from 1998 to 2002 (2.1%, 1.8%).

CONCLUSION

Our bibliometric analysis showed the characteristics and trends of publications on EVAR over a period of 25 years. The results of the bibliometric analysis revealed the quantitative improvements of publications and the qualitative improvements in challenging EVAR.