Pre-clinical Evaluation of a New Generation Bridging Stent for Fenestrated Endovascular Aneurysm Repair Using Realistic 3D Printed Aneurysm Models.

Abstract

The aim of this study was to perform a comparative pre-clinical evaluation of a new fenestrated endovascular aneurysm repair dedicated stent using perfused 3D printed patient anatomies. The test setup included a pulsatile pump set to reproduce human haemodynamics, four 3D printed pararenal aneurysms connected to a bench test, and four corresponding fenestrated grafts (Zenith Fenestrated; Cook, Bloomington, IN, USA). Bridging stents were sized based on analysis of patients computed tomography scans and included either four standard covered stents (BeGraft [BG]; Bentley, Hechingen, Germany) or four similar covered stent grafts mounted on a modified balloon to allow stent implantation and flaring in one step (BeFlared [BF]; Bentley). Each anatomy and corresponding endograft was used for four sets of four bridging stent implantations. Selective angiography following each stent implantation was used to assess efficacy (patency and absence of type Ic or IIIc endoleak), procedure time was recorded, and cone beam computed tomography at the end of each set of four stent implantations enabled comparison of geometric layout between stents. Physician assessment evaluated technical performance and failure modes. Sixty four stents were successfully implanted. Selective angiograms depicted three type IIIc (two in BG, one in BF) and seven type Ic (four in BG, three in BF) endoleaks, which were all corrected intra-operatively. Compared with BG, the BF had a larger mean proximal diameter inside the endograft (10.5 mm vs. 9.2 mm; p < .001) and greater opening flaring angle (46.1° vs. 33.4°; p < .001). The eight procedures performed with the BF were quicker than BG (17.0 ± 4 minutes vs. 23.9 ± 4.7 minutes; p = .004). Physician assessment did not reveal any failure mode and concluded an excellent technical performance of both devices. The BF demonstrated similar efficacy and performance compared with the BG for bridging target vessels in an innovative test setup using 3D printed patient anatomies.