Numerical simulations of thoracic endovascular aortic repair (TEVAR) may be implemented in the preoperative workflow if credible and reliable. We present the application of a TEVAR simulation methodology to an 82-year-old woman with a penetrating atherosclerotic ulcer in the left hemiarch, that underwent a left common carotid artery to left subclavian artery bypass and consequent TEVAR in zone 2. During the intervention, kinking of the distal thoracic stent graft occurred and the simulation was able to reproduce this event. This report highlights the potential and reliability of TEVAR simulations to predict perioperative adverse events and short-term postoperative technical results. (J Vasc Surg Cases Innov Tech 2023;9:101269.

Bissacco, Daniele

Domanin, Maurizio

Luraghi, Giulia

Mandigers, Tim J

Migliavacca, Francesco

Ramella, Anna

Trimarchi, Santi

van Herwaarden, Joost A

English

Archivio istituzionale della ricerca - Politecnico di Milano

From tFondDepathe DPoliteComFundedAuthorand sTM andFM andAdditioCorrespdale(e-maThe edidisclomanu2468-4 2023Surgecreathttps://Utilizing numerical simulations to prevent stent graftkinking during thoracic endovascular aortic repairTim J. Mandigers, MD,a,b Anna Ramella, MS,c Daniele Bissacco, MD,a Maurizio Domanin, MD,a,dJoost A. van Herwaarden, MD, PhD,b Giulia Luraghi, PhD,c Francesco Migliavacca, PhD,c andSanti Trimarchi, MD, PhD,a,d Milan, Italy; and Utrecht, The NetherlandsABSTRACTNumerical simulations of thoracic endovascular aortic repair (TEVAR) may be implemented in the preoperative workflowif credible and reliable. We present the application of a TEVAR simulation methodology to an 82-year-old woman with apenetrating atherosclerotic ulcer in the left hemiarch, that underwent a left common carotid artery to left subclavianartery bypass and consequent TEVAR in zone 2. During the intervention, kinking of the distal thoracic stent graft occurredand the simulation was able to reproduce this event. This report highlights the potential and reliability of TEVARsimulations to predict perioperative adverse events and short-term postoperative technical results. (J Vasc Surg CasesInnov Tech 2023;9:101269.)Keywords: Computational modeling; Finite element analysis; Patient-specific in silico model; TEVAR; Thoracicendovascular aortic repairNumerical simulations that virtually reproduce thoracicendovascular aortic repair (TEVAR) represent innovativecomputational adjuncts that may potentially aid thepreprocedural planning phase in the future by predict-ing perioperative or short-term postoperative technicalevents and results.1 Such tools could be further opti-mized regarding their credibility and reliability byproviding evidence of their effectiveness and workflow,as illustrated in this study that applied a recently devel-oped TEVAR simulation methodology to a patient-specific case with preoperative distal thoracic aortiche Section of Vascular Surgery, Cardio Thoracic Vascular Department,azione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milana; thertment of Vascular Surgery, University Medical Center Utrecht, Utrechtb;epartment of Chemistry, Materials and Chemical Engineering “G. Natta”,cnico di Milano, Milanc; and the Department of Clinical Sciences andmunity Health, Università degli Studi di Milano, Milan.dby MIUR FISR-FISR2019_03221 CECOMES.conflict of interest: F.M. is consultant for Medtronic Inc. S.T. is consultantpeaker for Medtronic Inc., W.L. Gore & Associates, and Terumo Aortic.AR contributed equally and share first authorship.ST contributed equally and share senior authorship.nal material for this article may be found online at www.jvscit.org.ondence: Tim J. Mandigers, MD, Fondazione IRCCS Cà Granda Ospe-Maggiore Policlinico di Milano, Via Francesco Sforza 35, 20122 Milan, Italyil: mandigers.tim@gmail.com).tors and reviewers of this article have no relevant financial relationships tose per the Journal policy that requires reviewers to decline review of anyscript for which they may have a conflict of interest.287The Author(s). Published by Elsevier Inc. on behalf of Society for Vascularry. This is an open access article under the CC BY license (http://ivecommons.org/licenses/by/4.0/).doi.org/10.1016/j.jvscit.2023.101269stent graft kinking. The patient provided informedconsent for the publication of this case report andrelated imaging.CASE REPORTAn 82-year-old woman with hypertension and a history ofheavy smoking (approximately 20 cigarettes per day) presentedwith a penetrating atherosclerotic ulcer (PAU) in the left hemi-arch with maximum axial diameters of 38  37 mm oncomputed tomography angiography (CTA). There were nofurther relevant cardiovascular diseases or interventions in hermedical history. Additionally, an intraluminal floating thrombuslocated at the outer curvature of the proximal descending aorta(approximately 18 mm length, 15  8 mm diameter) was identi-fied on CTA, that seemed to be connected to the intraluminalthrombus of the PAU anteriorly (Fig 1, A).First, a left common carotid artery (LCCA) to left subclavian ar-tery (LSA) bypass was performed, to obtain an adequate prox-imal landing zone in zone 2 for TEVAR. During the sameintervention, a Valiant thoracic aortic stent graft with the Capti-via delivery system (Valiant Captivia, VAMF3232C100TU) (Med-tronic Inc., Minneapolis, MN) was deployed followed by a plugat the LSA origin to prevent retrograde type II endoleak. Interest-ingly, during the intervention, a kinking of the thoracic stentgraft occurred between the fifth and sixth nitinol stent rings atthe distal portion of the thoracic stent graft in zone 4, whichwas resolved after ballooning this portion of the stent graft(Fig 1, B).The postoperative course was regular, without any adverseevents, including neurological and peripheral thromboembolic.Postoperative CTA after 8 days showed adequate exclusion ofthe PAU and intraluminal thrombus, without endoleak andpatency of the Valiant Captivia and LCCA to LSA bypass (Fig 1,1Fig 1. (A) Preoperative computed tomography angiography (CTA) imaging. (B) Fluoroscopy illustrating thedistal stent graft kinking, resolved by ballooning as shown on the final angiogram. (C) Technical results as seenon postoperative CTA after 8 days. LSA, left subclavian artery; PAU, penetrating atherosclerotic ulcer; TEVAR,thoracic endovascular aortic repair.2 Mandigers et al Journal of Vascular Surgery Cases, Innovations and TechniquesSeptember 2023C). Discharge was on postoperative day 11. During follow-up, co-lor Doppler ultrasound examination showed adequate patencyand flow over the LCCA-LSA bypass. No further follow-up diag-nostic imaging has been performed to date.The patient-specific ascending, arch, and descending aorticanatomy were reconstructed from preoperative CTA images,including the intraluminal thrombus in zone 3. A recentlydeveloped high-fidelity numerical methodology2,3 was adop-ted to simulate Valiant Captivia deployment in the recon-structed patient-specific anatomy. Simulations were carriedout using the commercial finite element LsDyna software(Ansys Inc., Canonsburg, PA) on 28 CPUs and 250 GB of RAMmemory. The device model incorporated nitinol stent prestressand underwent complete mechanical characterization.2 Asduring the intervention, a Valiant Captivia was deployed atthe distal border of the LCCA. The numerical method wasable to reproduce the kinking of the thoracic stent graft be-tween the fifth and sixth nitinol rings. Ballooning of the stentgraft was virtually replicated as well, to resolve the kinking(Fig 2, Supplementary Video, online only). The reliability of thesimulation was evaluated by qualitatively comparing the stentgraft configuration segmented from postoperative CTA imageswith the numerical results obtained by the simulation: therewas a satisfactory overlap (Fig 2). In terms of quantitative assess-ment, the opening area at each nitinol stent ring (expressed asa percentage error between the simulation and CTA segmenta-tion in square millimeters) remained <10%, with higher valuesin the region of the thrombus at the outer arch curvature(Fig 2).DISCUSSIONThe potential impact of applying this methodologicalTEVAR simulation model with Valiant Captivia topatient-specific cases could be of significant value duringpreprocedural planning given the ability to predict bothperioperative adverse events (such as kinking for theillustrated case) and short-term postoperative technicalresults. As an additional tool, it may serve physicians inchoosing the optimal proximal and/or distal sealingzones in specific cases with challenging aortic anatomy.In fact, as depicted in Fig 3, a simulation was performedto evaluate the stent graft apposition and kinking with aFig 2. Workflow of the numerical simulation and comparison of the simulation results with postoperativecomputed tomography angiography (CTA) image segmentation. TEVAR, thoracic endovascular aortic repair.Journal of Vascular Surgery Cases, Innovations and Techniques Mandigers et al 3Volume 9, Number 3more distal landing zone. In this scenario, we noted thatthe distal kinking disappeared and that the third nitinolstent ring bulged into the PAU. However, thisconfiguration might not be optimal, not only becauseof proximal landing zone reduction, but also because ofthe increased distance between the aorta and stentgraft.The time to obtain virtual results is compatible with thetime needed to plan elective TEVAR; this procedure canbe performed in 1 day. Furthermore, other patient-specific components such as the presence of intralumi-nal thrombus (as for this case) or calcifications, can beincluded in the simulation, to evaluate their impact onthe stent graft deployment. Virtual deployment ofdifferent thoracic aortic stent grafts of different manufac-turers, if verified and validated,4 may also help to find themost suitable device with optimal sealing for differentpatient-specific aortic anatomies that vary according togeometrical characteristics (eg, diameter, length, angula-tion, and tortuosity).Similar to the present case, another illustrative case byDerycke et al5 has previously demonstrated the potentialof a FE custom-made double branch Relay (TerumoAortic, Sunrise, FL) TEVAR simulation for an aortic archaneurysm, to reliably find stent graft collapse that ledto postoperative complications. This TEVAR simulationfound the deformation of the three nitinol stent ringsat the same location as seen on postoperative CTA.Also in our case, the simulation was performed afterthe clinical procedure to verify if the numerical modelwas able to predict the perioperative stent graft kinkingduring the intervention. In our patient-specific case, theevent wasmanaged promptly by using a balloon withoutclinical and technical consequences.CONCLUSIONSThis study further highlights the potential and reliabilityof TEVAR simulations to be adopted in and facilitate pre-procedural planning in the future. For example, theycould investigate optimal proximal landing and stentgraft apposition or the ideal stent graft model indemanding aortic anatomies. One of the challengesbefore a wider implementation of such tools in daily clin-ical cardiovascular practice, remains the need to furtherFig 3. Virtual scenario of a more distal landing zone and comparison to the actual one in terms of distancebetween the stent graft and the aortic wall.4 Mandigers et al Journal of Vascular Surgery Cases, Innovations and TechniquesSeptember 2023enhance simulations regarding their reliability and cred-ibility, by providing evidence of their effectiveness andworkflow, as illustrated by this case.REFERENCES1. Mandigers TJ, Ramella A, Bissacco D, et al. Thoracic stent graft nu-merical models to virtually simulate thoracic endovascular aorticrepair: a scoping review. Eur J Vasc Endovasc Surg 2023. doi: 10.1016/j.ejvs.2023.06.006.2. Ramella A, Migliavacca F, Rodriguez Matas JF, et al. Validation andverification of high-fidelity simulations of thoracic stent-graft implan-tation. Ann Biomed Eng 2022;50:1941-53.3. Ramella A, Migliavacca F, Rodriguez Matas JF, et al. Applicabilityassessment for in-silico patient-specific TEVAR procedures. J Biomech2023;146:111423.4. American Society of Mechanical Engineers. Assessing credibility ofcomputational modeling through verification and validation: appli-cation to medical devices - V&V 40. ASME; 2018.5. Derycke L, Avril S, Perrin D, Albertini JN, Cochennec F. Computersimulation model may prevent thoracic stent-graft collapse compli-cation. Circ Cardiovasc Imaging 2022;15:e013764.Submitted May 17, 2023; accepted Jun 17, 2023.Additional material for this article may be found onlineat www.jvscit.org.

Utilizing numerical simulations to prevent stent graft kinking during thoracic endovascular aortic repair

https://re.public.polimi.it/bitstream/11311/1253258/1/2023%20MANDIGERS%20-%20Utilizing%20numerical%20simulations%20to%20prevent%20stent-graft%20kinking%20during%20throacic%20endovascular%20aortic%20repair.pdf

Utilizing numerical simulations to prevent stent graft kinking during thoracic endovascular aortic repair

Abstract

Similar works

Full text

Available Versions

Archivio istituzionale della ricerca - Politecnico di Milano