(IP265) Spatial Relationships of Visceral and Renal Fenestrations in a Series of Physician Modified Endografts

Objectives: Fenestrated endovascular aneurysm repair(FEVAR) is a key modality in the treatment of complex abdominal aortic aneurysm(cAAA). Physician-modified endografts(PMEGs) are a flexible and timely solution increasingly used in cAAA that are not amenable to commercially available or clinical trial endografts. However, little is known about the typical placement of fenestrations in PMEGs. We aim to describe the typical positions of visceral fenestrations in PMEG.

Methods: We included patients who underwent FEVAR with PMEGs between 10/2017-12/2024 at an institution. Patients underwent treatment as lead-in or part of a physician-sponsored investigational device exemption trial (NCT06501872, IDE#G240122). Basic demographic information and type of aneurysm were recorded. Centerline-reformat 3-dimensional computer models were drafted from CT scans to guide placement of fenestrations on the modified endograft. The position of fenestrations for the celiac, left renal (LRA) and right renal (RRA) was recorded relative to the superior mesenteric artery (SMA), with vertical distance from SMA recorded in millimeters and radial position measured in clockface direction. The position of the SMA was standardized to 0mm vertical and 12:00 radially.

Results: 177 patients (mean age 75±7.92 years, 71.3% male) met inclusion criteria and underwent PMEG by one of two surgeons. The most common type of AAA was pararenal (46.3%); thoracoabdominal aneurysms comprised 29.3% of the cohort (Table 1). Figure 1 depicts the locations of the fenestrations (boxes circumscribe 90% of patients). The mean position of the celiac fenestration was 20mm above the SMA fenestration and at 12:25 radially. The mean position of the RRA fenestration was 14 mm below the SMA fenestration and at 9:40 radially, and the mean position of the LRA fenestration was 18mm below the SMA and at 2:44 radially. In 90% of patients, the vertical position of the celiac fenestration was 14-29mm above the SMA, while for the RRA it was 2-28mm below the SMA, and for the LRA, 4-35mm below the SMA. In 90% of patients the radial position of the celiac fenestration was between 12:00-1:00, while for RRA it was between 8:36-10:24, and for the LRA between 1:48-3:36. Intraoperative target vessel cannulation and delivery of bridging stent grafts were 100%.

Conclusions: The position of the celiac fenestration lies within a narrow vertical and radial range in a large proportion of patients, while there is more variability in the location of the renal fenestrations. This descriptive study may guide surgeons in planning PMEGs, as well as guide the development of off-the-shelf stent-grafts that maximize universal anatomic suitability.