What is wrong with EVAR and how would a perfect device overcome the - - PowerPoint PPT Presentation

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Apr 06, 2023 523 likes •925 views

What is wrong with EVAR and how would a perfect device overcome the problems? Bijan Modarai Professor of Vascular Surgery Academic Department of Vascular Surgery Guys & St Thomas NHS Foundation Trust, Kings College London

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Bijan Modarai

Professor of Vascular Surgery

Academic Department of Vascular Surgery Guy’s & St Thomas’ NHS Foundation Trust, King’s College London

What is wrong with EVAR and how would a perfect device

vercome the problems?

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Disclosures

Cook:

Proctoring, Speaker’s fees, Grant support, Consulting

Cydar Medical:

Scientific advisory board

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DREAM Medicare Data EVAR 1

Schermerhorn et al. N Eng J Med 2015 Van Schaik et al. J Vasc Surg 2017 Patel et al. Lancet 2016

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~50% survival at 10 years

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Van Schaik et al. J Vasc Surg 2017 Patel et al. Lancet 2016

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Reintervention

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Malignancy Risk?

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Stent graft evolution

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Stent graft evolution

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Materials Fixation Profile Deployment

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Disease progression Case selection Radiation exposure Device integrity Device fixation Endoleak Limb occlusion Surveillance EVAR Challenges

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Force to dislodge stent graft 6X less than sutured anastomosis.

Resch et al. EJVES 2000

Active fixation reduces migration

➢ Cadaveric model ➢ Fixation hooks/barbs: Higher DF ➢ Less migration

Melas et al. EJVES 2010

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Talent, Excluder, Aneurx, Zenith Factors associated with migration: Aneurysm diameter Neck length

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Neck length

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Current endograft technology relies almost exclusively on mechanical interaction between device and native vessels to afford stability

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J Thorac Cardiovasc Surg 2014;148:2325-34

➢Canine model ➢Enhanced neointimal formation and fibrous tissue ➢Strengthening the mechanical force of attachment graft/aorta.

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➢ Maintenance of aortic integrity at seal zones…… ➢ Risk factors: thrombus, ectasia, synchronous aneurysms ➢ Occult underlying genetic factors? ➢ Oversizing promotes degeneration

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Stent grafts that “fail well”

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Joviliano B J Cardiovasc Surg 2017

Aneurysmal disease

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➢Leucocyte produces elastase ➢Elastase murine model ➢AZD9668 (AtraZeneca elastase inhibitor) ➢Inhibits aneurysm progression

Delbose et al. JVS 2016

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Prior to relining After relining

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Courtesy of Nabil Chafke/Geprovas

➢Fabric/metal wire interaction ➢Abrasion: Calcified plaques ➢Increase with time? ➢New generation materials

Aging implants

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Aneurysm sac management

➢ Endoleak at 30 days: Heralds re-intervention ➢ Malignant type 2 endoleaks ➢ Endoleaks masquerading as type 2 ➢ Relevance of sac content? ➢ Advanced imaging of sac/aortic wall ➢ Devices that obliterate sac

Sterbergh et al. J Vasc Surg 2008

Inferior mesenteric artery Lumbar artery

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➢ Ideal system: Low profile Well supported limbs Flexible/compliant Vessel stenosis: Radial force Flexible/hydrophilic delivery system Percutaneous ➢ Low profile: Compromise on materials?

Device profile and hostile iliac anatomy

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How hard should we strive to increase applicability of devices? Adverse anatomy → Complications Carefully executed EVAR with conservative IFU performs well

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➢ Objective case selection

Accounting for multiple nuances Deformation Available neck length Stent graft conformation Precise deployment

➢ Stent graft longevity ➢ Patient longevity ➢ Tailored surveillance

The future: Imaging, AI and machine learning

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Light pulse reflection

Courtesy of Dr. Joost van Herwaarden, UMC-U, NL and Philips

➢ Real time 3D device visualisation using light ➢ Multiple unrestricted viewing angles ➢ Corresponding alignment markers on stent graft?

Fiber Optic RealShape (FORS) technology

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Oliveira et al. IEEE 2012

ALERT

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➢ Iterative improvements from lessons of past ➢ Paradigm shifts still possible? - Yes ➢ Novel technology: Increasing regulatory scrutiny

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Towards Perfection

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Incorporates into seals zones

Perfection

Actively prevents disease progression Flexibility, strength, support, durable, low profile, precise delivery Facilitates proximal/distal extension Obliterates aneurysm sac Radiation free implantation/surveillance Actively warns of malfunction

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Radiation MRI compatible graft materials - no artefact FORS and markers on graft that allow you to see exactly where You are – wire in renal and markers on graft – then you deploy

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Images Courtesy of Athanasios Saratzis