Local Hemodynamic Changes and Branch Outcomes Associated with Inner Branched versus Outer Branched Stent Grafts

This study compared the hemodynamic performance and branch outcomes of outer branched (t-Branch) and inner branched (E-nside) stent-graft designs.

Patient-specific computational fluid dynamics (CFD) simulations were performed on patients who underwent four-vessel branched endovascular aortic repair with E-nside (n = 12) or t-Branch (n = 11) between November 2013 and March 2024, using three-dimensional reno-visceral aortic geometry models reconstructed from pre- and postimplantation computed tomography images. Hemodynamic parameters at the branches (23 celiac arteries [CAs], 23 superior mesenteric arteries [SMAs], 23 right renal arteries [RRAs], 23 left renal arteries [LRAs]) were compared along with the clinical outcome data.

E-nside and t-Branch showed comparable all-four-bridging stent patency (patient-level P = 1.0; stent-level P = 0.46) and reintervention rates (patient-level P = 1.0; stent-level P = 1.0). There were no significant differences in either peak flow changes (Δ) (CA, P = 0.69; SMA, P = 0.26; RRA, P = 0.1; LRA, P = 0.21) or peak pressure Δ (CA, P = 0.26; SMA, P = 0.38; RRA, P = 0.35; LRA, P = 0.35) in all branches between the groups. While postimplantation changes in time-averaged wall shear stress in the main aortic segment were not significantly different between endograft strategies (E-nside 6.4 dyn/cm² vs t-Branch 9.2 dyn/cm², P = 0.1), aortic displacement force (DF) differed significantly (E-nside 4.9 N vs t-Branch 8.1 N, P = 0.002).

Despite geometric differences, the t-Branch and E-nside devices showed similar outcomes for patency and reintervention, with CFD simulation analysis indicating no significant impact on local branch hemodynamics. However, the t-Branch may be associated with higher DF in the device's aortic segment compared to the E-nside.