The Correlation Of Aortic Neck Length To Late Outcomes Following EVAR with the Ovation Stent Graft

Prediction of Late Proximal Endoleak Risk after EVAR by Preoperative Estimation of Endograft/Aortic Neck Apposition Surface

BACKGROUND

The aim of this study was to evaluate a new measurement tool for the preoperative computed tomography (CT) scan to estimate the endograft apposition surface on the proximal aortic neck of the aneurysm that would predict the risk of late type IA endoleak (EL1A).

METHODS

From databases of 4 high-volume centers between 2004 and 2020, all patients who underwent Endovascular Aneuruysm Repair (EVAR) with the possibility of analyzing pre and post-EVAR scans and who presented late (>2 years) EL1A in follow-up were included retrospectively (EL1A group). A control group of randomly selected EL1A-free patients were included (control group) and followed-up beyond 4 years. The measurement tool (Endosize, Therenva) was used to model a virtual cylinder constrained by the centreline whose diameter was determined from the diameter of the implanted endograft. The apposition surface was calculated by determining the areas of the virtual cylinder mesh outside the mesh of the neighboring portion of the segmented aorta by an intersection calculation of surface normals. This apposition surface and the usual anatomical data of the proximal neck were compared between the groups with univariate and multivariate analyses. Intra and interobserver variability in the measurement of apposition surface was analyzed using the intraclass correlation coefficient (ICC) and the method of Bland and Altman.

RESULTS

Sixty-six comparable patients were included as follows: 33 in the EL1A group and 33 in the control group. The mean time to EL1A onset was 50.2 ± 24.6 months in the EL1A group, and the mean follow-up time was 79.8 ± 26.8 months in the control group. In univariate analysis, only the endograft apposition surface ratio on the proximal neck was significantly lower in the EL1A group compared with the control group (50.3% vs. 75.5%; P < 0.0001). There was no significant difference in classic anatomical neck characteristics. There was no difference in proximal endograft oversizing or in the length from the lowest renal artery to the beginning of the covered portion of the endograft. In multivariate analysis, only the apposition surface ratio was independently correlated with the presence of EL1A (P < 0.0001). The estimation of the intra and interobserver variability indicates excellent reliability (ICC = 0.992; ICC = 0.956).

CONCLUSIONS

The method estimating the preoperative endograft apposition surface on the proximal aortic neck appears to be a reliable measuring technique in predicting the risk of occurrence of late EL1A after EVAR.

Unsupervised machine learning cluster analysis to identification EVAR patients clinical phenotypes based on radiomics

OBJECTIVE

This study used unsupervised machine learning (UML) cluster analysis to explore clinical phenotypes of endovascular aortic repair (EVAR) for abdominal aortic aneurysm (AAA) patients based on radiomics.

METHOD

We retrospectively reviewed 1785 patients with infra-renal AAA who underwent elective EVAR procedures between January 2010 and December 2020. Pyradiomics was used to extract the radiomics features. Statistical analysis was applied to determine the radiomics features that related to severe adverse events (SAEs) after EVAR. The selected features were used for UML cluster analysis in training set and validation in test set. Comparison of basic characteristics and radiomics features of different clusters. The Kaplan-Meier analysis was conducted to generate the cumulative incidence of freedom from SAEs rate.

RESULT

A total of 1180 patients were enrolled. During the follow-up, 353 patients experienced EVAR-related SAEs. In total, 1223 radiomics features were extracted from each patient, of which 23 radiomics features were finally preserved to identify different clinical phenotypes. 944 patients were allocated to the training set. Three clusters were identified in training set, in which patients had identical clinical characteristics and morphological features, while varied considerably of selected radiomics features. This encouraging performance was further approved in the test set. In addition, each cluster was well differentiated from other clusters and Kaplan-Meier analysis showed significant differences of freedom from SAEs rate between different clusters both in the training (p = .0216) and test sets (p = .0253).

CONCLUSION

Based on radiomics, UML cluster analysis can identify clinical phenotypes in EVAR patients with distinct long-term outcomes.

The Challenge of Treating Abdominal Aortic Aneurysms with Hostile Neck Anatomy: An Overview

Hostile aortic neck anatomy challenges the outcomes of endovascular abdominal aortic aneurysm repair (EVAR). Besides reverting to open surgical repair (OSR), thoughtful endograft selection and a number of advanced endovascular techniques have been suggested as potential solutions for preventing proximal seal zone complications, improving EVAR durability, and preventing aneurysm-related death. Each technique is associated with advantages and limitations and there has not been a credible direct comparison amongst them in the form of a well-designed prospective trial. The not infrequent presence of multiple hostile anatomic characteristics further complicates decision making and challenges the surgeon's skills. This paper serves as an overview of hostile neck anatomy and its implications on EVAR. We provide a concise literature review with the purpose of outlining the treatment modalities and outcomes in this patient population.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.