Physician-Modified Stent-Grafts Created in the Three-Dimensionally Aortic Template Have Better Reliability and Greater Alignment With the Target Vessels Than Stent-Grafts Modified Based on Measurements From Computed Tomography

Abstract

Purpose:

Physician-modified stent-grafts (PMSG) are widely used, especially when a patient’s condition precludes waiting for a custom-made device. In recent years, the modification process has been upgraded using 3-dimensional (3D) aortic templates. Nonetheless, the reliability of PMSG and accuracy of fenestration alignment with the target vessel are not known. Thus, the study is aimed to fulfill the gap in current knowledge.

Materials and Methods:

Ten computed tomographic (CT) scans of aortic aneurysm previously treated with the fenestrated endovascular repair were selected to 3D-print aortic templates and elastic vessel phantoms. Two vascular surgeons performed fenestrations using the 3D template and modification plan based on CT measurements. Two operators each performed 10 fenestrated stent-grafts in the aortic template and 10 using CT measurements, for a total of 40 fenestrated stent-grafts. Then, stent-grafts were implanted in elastic vessel phantoms, which served to evaluate fenestration alignment with the target vessel. The alignment was judged in a 5-point scale: 0%, 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. The distances between fenestrations served to calculate interobserver variability for both methods. The measurements were processed as interclass correlation coefficient (ICC), Pearson and Spearman correlation, and Bland-Altman plots.

Results:

PMSG created with a 3D template had higher interclass correlation coefficient values and Pearson/Spearman correlation than fenestrations created from CT measurements. The rate of fenestration alignment with the target vessel was higher for PMSG created with a 3D template (p=0.007).

Conclusions:

PMSGs created with a 3D template are more reliable and have better fenestration alignment with the target vessel than PMSGs created based on CT measurements.