Purpose: The purpose of the study was to provide a consensus definition of the infrarenal sealing zone and develop an algorithm to determine when and if adjunctive procedure(s) or reintervention should be considered in managing patients undergoing endovascular aortic repair (EVAR) for infrarenal abdominal aortic aneurysm (AAA). Methods: A European Advisory Board (AB), made up of 11 vascular surgeons with expertise in EVAR for AAA, was assembled to share their opinion regarding the definition of preoperative and postoperative infrarenal sealing zone. Information on their current clinical practice and level of agreement on proposed reintervention paths was used to develop an algorithm. The process included 2 virtual meetings and 2 rounds of online surveys completed by the AB (Delphi method). Consensus was defined as reached when ≥ 8 of 11 (73%) respondents agreed or were neutral. Results: The AB reached complete consensus on definitions and measurement of the pre-EVAR target anticipated sealing zone (TASZ) and the post-EVAR real achieved sealing zone (RASZ), namely, the shortest length between the proximal and distal reference points as defined by the AB, in case of patients with challenging anatomies. Also, agreement was achieved on a list of 4 anatomic parameters and 3 prosthesis-/procedure-related parameters, considered to have the most significant impact on preoperative and postoperative sealing zones. Furthermore, the agreement was reached that in the presence of visible neck-related complications, both adjunctive procedure(s) and reintervention should be contemplated (100% consensus). In addition, adjunctive procedure(s) or reintervention can be considered in the following cases (% consensus): insufficient sealing zone on completion imaging (91%) or on the first postoperative computed tomography (CT) scan (91%), suboptimal sealing zone on completion imaging (73%) or postoperative CT scan (82%), and negative evolution of the actual sealing zone over time (91%), even in the absence of visible complications. Conclusions: AB members agreed on definitions of the pre- and post-EVAR infrarenal sealing zone, as well as factors of influence. Furthermore, a clinical decision algorithm was proposed to determine the timing and necessity of adjunctive procedure(s) and reinterventions.

Imaging surveillance following endovascular aneurysm repair (EVAR) is strictly recommended. This study investigates the value of endograft apposition and position relative to the aortic neck on the first postoperative computed tomography angiography (CTA) in determining patients at risk for a late type Ia endoleak (T1aEL). Materials and Methods: Patients with a T1aEL after the first postoperative CTA were selected from a consecutive database and matched with uncomplicated controls. Endograft apposition and position, including the shortest apposition length (SAL), were determined on the first postoperative CTA. The SAL is the shortest distance between the proximal endograft fabric and the first slice where circumferential apposition with the aortic wall is lost. Differences in endograft apposition at the first postoperative CTA were compared between groups. Logistic regression analysis identified independent predictors for late T1aEL. Results: A total of 32 patients with a late T1aEL were included and matched with 32 uncomplicated controls. Median follow-up after primary EVAR was 62.0 (interquartile range [IQR]: 36.8, 83.5) months in the T1aEL group compared with 47.5 (IQR: 34.0, 79.3) months in the control group; p=0.265. Median preoperative neck diameter was significantly larger in the T1aEL group than in the control group (26.6 [IQR: 24.9, 29.6] mm versus 23.4 [IQR: 22.5, 25.3] mm); p<0.001. Patients in the T1aEL group had a median SAL of 11.6 (IQR: 4.3, 20.5) mm compared with 20.7 (IQR: 13.1, 24.9) mm in the control group; p=0.002. SAL <10mm on the first postoperative CTA (odds ratio [OR]: 9.63, 95% confidence interval [CI]: 1.60-57.99) and larger neck diameter (OR: 1.80, 95% CI: 1.26-2.57) were independent predictors for developing a late T1aEL. Conclusion:Preoperative neck diameter and SAL on the first postoperative CTA following EVAR are important predictors for the development of a late T1aEL. Patients with a SAL of <10mm had a significantly higher risk of developing a late T1aEL. Future research should determine whether these patients would benefit from reintervention before an actual T1aEL is present. Clinical Impact Understanding the mechanisms of endovascular aneurysm repair failure is essential to further enhance clinical outcomes. Adequate proximal sealing is necessary to foster freedom from type 1a endoleak. This study demonstrates that the shortest apposition length (SAL) at the first postoperative computed tomography angiography (CTA) is able to identify patients at risk for a late type 1a endoleak. Especially patients with a SAL <10mm are at high risk. Currently, the guidelines advice repeated imaging with CTA in patients with a seal <10mm. Future research should determine whether these patients would benefit from re-intervention before an actual type 1a endoleak is present.

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groningen, the netherlands; 2 department of surgical and integrated diagnostic sciences (disC), university of genoa, genoa, italy; 3 vascular and endovascular surgery unit, irCCs ospedale Policlinico san Martino, genoa, italy

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