The Hemodynamic Impact of Misalignment of Fenestrated Endografts: A Computational Study

Abstract

We detected differences in the values of shear stress exerted on the stented arteries, depending on different positions that SG can adapt after the deployment of fenestrated EG. The pathophysiologic implication of our findings and their potential association with clinical events deserve further investigation and clinical validation.

Renal Outcomes Following Fenestrated and Branched Endografting

“…This increase in curvature and motion may apply more force and stress on stents implanted in this region. A model study from Georgakarakos 24 has analyzed multiple values of take off angle between the renal stent and the endograft. The narrow transitional zone between the bridging stent and the endograft presented the highest stress value correlated with endothelial damage and stent fatigue, and induced local thrombogenic activity compromising lumen patency.…”

The shear stess profile of the pivotal fenestrated endograft at the level of the renal branches: A computational study for complex aortic aneurysms

“…3 On the contrary, the intra-arterial segment seems to present an angle-dependent deviation in WSS values, with the highest value at 45 . However, the most striking deviation is focused at the transitional zone, where the 3:00' o'clock branch-orientation presents the lowest value while the WSS value at 45 (1:30' o'clock) is higher by 25%.…”

“…2 The mating branch in FEVAR protrude perpendicularly from the fenestrations and may be subjected to cephalad or caudal misalignments that can affect directly the wall shear stress (WSS) distribution and magnitude along the stent-grafts (SGs) as well as the maximum WSS values at the transitional zone between the bridging SG and the native vessel. 3 These stress alterations can predispose to myointimal hyperplasia, stenosis and subsequent occlusion, as illustrated in Figure 1(a). 4,5 An alternative, recently introduced in the literature, design for fenestrated endografting confers pivot branch devices which allow for easier catheterization of the target renal vessel with adaptation of a variant degree of angulation of the mating pivot branches in the transverse plane (pivotal-FEVAR, pFEVAR).…”

“…3 Initially, a 3D model of an AAA was reconstructed, based on typical values of an AAA (Table 2). Using these values cross-section profiles were constructed and interpolated to form the geometric body of the AAA.…”

Applying Findings of Computational Studies in Vascular Clinical Practice: Fact, Fiction, or Misunderstanding?

“…[16][17][18] Indeed, it seems difficult to compare the hemodynamic or clinical performance of different types of endografts between several patient groups, since certain patient-specific factors, e.g., the configuration of the iliac vessels and the level of peripheral occlusive disease, may confound the effect of the endograft's structural differences on limb patency and incidence of migration and endoleaks. [19][20][21][22] Consequently, under this perspective, subtle geometrical models of unusual or complex endograft patterns, such as the cross-limbs configuration [19][20][21] and fenestrated 22 designs, respectively, can be computationally examined, preceding or even inspiring large-scale clinical studies on the same issue. More intriguingly, as modeling techniques evolve, finite element analysis can be performed for direct comparisons of the mechanical stresses and strains acting on a number of commerciallyavailable device components under a variety of angulations, depicting potential advantages or drawbacks between them.…”