Type IIIb Endoleak and Relining: A Mathematical Model of Distraction Forces

Swaelens, Charles, Poole, Robert J ORCID: 0000-0001-6686-4301, Torella, Francesco ORCID: 0000-0003-0529-7387, McWilliams, Richard G, England, Andrew and Fisher, Robert K (2016) Type IIIb Endoleak and Relining: A Mathematical Model of Distraction Forces. JOURNAL OF ENDOVASCULAR THERAPY, 23 (2). pp. 297-301.

Text Swaelens_et_al_2016.pdf - Unspecified Download (9MB)

Abstract

<h4>Purpose</h4>To examine the changes in distraction force following relining of a conventional abdominal aortic stent-graft with a type IIIb endoleak using the Nellix endovascular sealing device compared to a unilateral stent-graft.<h4>Methods</h4>Relining is often used to repair type IIIb endoleaks, but the consequences to graft stability are unknown. A mathematical model was constructed based on pressure and volume flow through the stent-grafts, incorporating recognized distraction force equations. Steady flow was presumed at peak systolic pressures to calculate the maximum distraction force, with gravity ignored. Distraction forces for 28- to 36-mm-diameter stent-graft bodies with 16-mm limbs were calculated and compared to forces following relining with single and double Nellix devices or the Renu unilateral device.<h4>Results</h4>Distraction forces for the 28-, 32-, and 36-mm stent-grafts prior to relining were 5.99, 10.21, and 14.99 N, respectively. Similar forces were reported after relining with bilateral Nellix devices (5.86, 10.08, and 14.86 N, respectively). However, use of a unilateral Nellix increased the distraction forces to 9.92, 14.14, and 18.92 N, respectively. These were comparable to the increase observed after relining with a Renu unilateral stent-graft (9.87, 14.09, and 18.86 N, respectively). The proportional increase in distraction force for a unilateral relining ranged from 26% to 66%, with the greatest increase noted in the smaller diameter main bodies.<h4>Conclusion</h4>Relining a stent-graft with a type IIIb endoleak using bilateral Nellix devices does not increase the distraction force. However, a unilateral Nellix device or the Renu system could theoretically increase the distraction force by up to 66%, potentially risking migration and type Ia endoleak. In clinical practice, these results suggest that a relining with bilateral Nellix may have benefits over the Renu unilateral stent-graft.

Item Type:	Article
Uncontrolled Keywords:	abdominal aortic aneurysm, computational models, device failure, endoleak, endograft, endovascular aneurysm sealing, stent-graft
Depositing User:	Symplectic Admin
Date Deposited:	12 Apr 2016 11:20
Last Modified:	16 Dec 2022 17:00
DOI:	10.1177/1526602816631106
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3000435