The Impact of Stent Design on Proximal Stent-graft Fixation in the Abdominal Aorta: an Experimental Study

Resch, Timothy; Malina, Martin; Lindblad, Bengt; Malina, Janne; Brunkwall, Jan; Ivancev, Krassi

doi:10.1053/ejvs.1999.0991

Cited by 140 publications

(142 citation statements)

References 13 publications

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“…7 A number of factors hypothesized to affect device migration have been clinically investigated, including aortic neck diameter, length, and angulation; neck calcification and thrombus; neck enlargement; inadequate proximal and distal fixation length; and neck enlargement. [8][9][10] In-vitro 11 and in-vivo experimental studies, 12 as well as theoretical 13 and computational studies, [14][15][16][17][18][19] have been conducted to investigate the magnitude of the loads acting on endografts. These loads have been referred to as migration forces, displacement forces, or drag forces.…”

mentioning

confidence: 99%

Effect of Curvature on Displacement Forces Acting on Aortic Endografts: A 3-Dimensional Computational Analysis

Figueroa

Taylor

Yeh

et al. 2009

Journal of Endovascular Therapy

111

114

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¤ ¤Purpose: To determine the effect of curvature on the magnitude and direction of displacement forces acting on aortic endografts in 3-dimensional (3D) computational models.Method: A 3D computer model was constructed based on magnetic resonance angiography data from a patient with an infrarenal aortic aneurysm. Computational fluid dynamics tools were used to simulate realistic flow and pressure conditions of the patient. An aortic endograft was deployed in the model, and the displacement forces acting on the endograft were calculated and expressed in Newtons (N). Additional models were created to determine the effects of reducing endograft curvature, neck angulation, and iliac angulation on displacement forces. Results: The aortic endograft had a curved configuration as a result of the patient's anatomy, with curvature in the anterolateral direction. Total displacement force acting on the endograft was 5.0 N, with 28% of the force in a downward (caudal) direction and 72% of the force in a sideways (anterolateral) direction. Elimination of endograft curvature (planar graft configuration) reduced total displacement force to 0.8 N, with the largest component of force (70%) acting in the sideways direction. Straightening the aortic neck in the curved endograft configuration reduced the total force acting on the endograft to 4.2 N, with a reduction of the sideways component to 55% of the total force. Straightening the iliac limbs of the endograft reduced the total force acting on the endograft to 2.1 N but increased the sideways component to 91% of the total force. Conclusion: The largest component of the force acting on the aortic endograft is in the sideways direction, with respect to the blood flow, rather than in the downward (caudal) direction as is commonly assumed. Increased curvature of the aortic endograft increases the magnitude of the sideways displacement force. The degree of angulation of the proximal and distal ends of the endograft influence the magnitude and direction of displacement force. These factors may have a significant influence on the propensity of endografts to migrate in vivo.

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mentioning

confidence: 99%

Effect of Curvature on Displacement Forces Acting on Aortic Endografts: A 3-Dimensional Computational Analysis

Figueroa

Taylor

Yeh

et al. 2009

Journal of Endovascular Therapy

111

114

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“…Our predicted displacement forces echo those of other CFD studies which report values in the range of 4 to 10 N, as shown in Table 3. Experimental studies have indicated that older generations of stent-grafts (prior to the use of large barbed suprarenal stents) can only resist displacement forces of 2.5 to 8.0 N [32][33][34].…”

Section: Clinical Relevancementioning

confidence: 99%

“…37. Graph comparing anchoring force (in Newtons) for various proximal fixation strategies for stent grafts, from references [32][33][34].…”

Section: Clinical Relevancementioning

confidence: 99%

“…Dislodgement of the device could subsequently result in pressurized blood flowing into the aneurysm sac again. Newer generations of stent-grafts were reported to be able to resist displacement forces of up to 24 N [33,34], which offered a significant safety margin against device migration and displacement. However, a very recent paper has suggested that even some of the newer-generation stent-grafts can only resist forces of 6 N [35].…”

Section: Clinical Relevancementioning

confidence: 99%

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Computational Fluid Dynamics Modeling of Redundant Stent-Graft Configurations in Endovascular Aneurysm Repair

Tse

Shek

Nabovati

et al. 2010

Volume 2: Biomedical and Biotechnology Engineering

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During endovascular aneurysm repair (EVAR), if the stent-graft device is too long for a given patient the redundant (extra) length adopts a convex configuration in the aneurysm.Based on clinical experience, we hypothesize that redundant stent-graft configurations increase the downward force acting on the device, thereby increasing the risk of device dislodgement and failure. This work numerically studies both steady-state and physiologic pulsatile blood flow in redundant stent-graft configurations. Computational fluid dynamics simulations predicted a peak downward displacement force for the zero-, moderate-and severe-redundancy configurations of 7.36, 7.44 and 7.81 N, respectively for steady-state flow; and 7.35, 7.41 and 7.85 N, respectively for physiologic pulsatile flow. These results suggest that redundant stent-graft configurations in EVAR do increase the downward force acting on the device, but the clinical consequence depends significantly on device-specific resistance to dislodgement.ii

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“…AAAs with problematic proximal neck-short (from 5 to 15 mm), conical or with a long enough but angulated one -were excluded from EVAR preserving classical stentgrafting indications criteria due to the problematic stentgraft fixation [2][3][4] . The basic types of fixation such as stent-graft self-expansion, barbs, hooks or suprarenal bare wire fixation in the more stable part of aorta are not adequate in these cases of proximal neck anatomy [5][6][7][8][9] . One possibility for providing successful stent-graft fixation is the use of associated surgery -external aortic banding 10 .…”

Section: Introductionmentioning

confidence: 99%

Banding in Aortic Stent-Graft Fixation in Evar

Utíkal¹,

Köcher²,

Bachleda³

et al. 2004

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub

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The Impact of Stent Design on Proximal Stent-graft Fixation in the Abdominal Aorta: an Experimental Study

Cited by 140 publications

References 13 publications

Effect of Curvature on Displacement Forces Acting on Aortic Endografts: A 3-Dimensional Computational Analysis

Effect of Curvature on Displacement Forces Acting on Aortic Endografts: A 3-Dimensional Computational Analysis

Computational Fluid Dynamics Modeling of Redundant Stent-Graft Configurations in Endovascular Aneurysm Repair

Banding in Aortic Stent-Graft Fixation in Evar

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