«Which stent for which coarctation based on mechanical properties?» Modelisation Patrice Guérin, Clément Mercier, Fabienne Jordanna L Institut du Thorax et Inserm U791 CHU Nantes JFCPC 2015
Déclaration de Relations Professionnelles Disclosure Statement of Financial Interest J'ai actuellement, ou j'ai eu au cours des deux dernières années, une affiliation ou des intérêts financiers ou intérêts de tout ordre avec une société commerciale ou je reçois une rémunération ou des redevances ou des octrois de recherche d'une société commerciale : I currently have, or have had over the last two years, an affiliation or financial interests or interests of any order with a company or I receive compensation or fees or research grants with a commercial company : Affiliation/Financial Relationship Grant/Research Support Consulting Fees/Honoraria Major Stock Shareholder/Equity Royalty Income Ownership/Founder Intellectual Property Rights Other Financial Benefit Company Lilly AstraZeneca Actelion Abbott Vascular
The laboratory Bench test : Camera Binocular magnifying glass Microscanner In-vivo studies Rats Rabbits Pigs
3D reconstruction
In vivo analysis
Pigs : In vivo analysis (2)
Scanning electron microscopy (J28)
Aortic coarctation 8
Texture analyzer TA HD PLUS Measuring the force versus displacement Max Force ± 5kg ± 500kg Force Resolution 0.1g 10g Force Accuracy 0.025% 0.025% Texture Technology
Caliper Measuring range Resolution 0-150mm 0.01mm Fischer scientific 10
Analysed stents Modèle Laboratoire Composition Diamètre d'usage Longueur d'usage AndraStent XL ANDRAMED Cobalt-Chronium 14-25 mm 14-25 mm 1 n AndraStent XXL ANDRAMED Cobalt-Chronium 20-32 mm 16-24 mm 1 Valéo BARD Stainless steel 316L 9 mm NC 2 Covered CP stent 16 mm NuMED Platinium/Iridium (90/10) Covered CP stent 28 mm NuMED Platinium/Iridium (90/10) CP stent 55 mm NuMED Platinium/Iridium (90/10) 12-24 mm 10,5-16,1 mm 1 12-24 mm 19,1-26,2 mm 1 12-24 mm NC 1 Palmaz CORDIS Stainless steel 316L 14-25 mm 37,79-30,58 mm IntraStent Mega LD Stent Ev3 Stainless steel 316L 9-12 mm 26 mm 1 1 IntraStent Max LD Stent Ev3 Stainless steel 316L 12 mm 26 mm 2 IntraStent DoubleStrut LD Stent Ev3 Stainless steel 316L 9-12 mm 56 mm 1
Mechanical tests Recoil and foreshortening Averall compression Overall Radial Force Local compression Segmental Radial Force Longitudinal compression
Mechanical tests Recoil and foreshortening Averall compression Overall Radial Force Local compression Segmental Radial Force Longitudinal compression
Recoil et du Foreshortening Recoil : Diametrical reduction after balloon deflation Foreshortening : Longitudinal reduction between the initial and final state of the stent
Initial Recoil 7,00 % After first inflation at 18 mm Minus 1 mm after deflation in case of 18-20 mm vessel 6,00 % 5,19 % 5,00 % 4,03 % 4,00 % 3,36 % 3,58 % 3,68 % 3,00 % 2,48 % 2,73 % 2,00 % 1,82 % 1,85 % 1,00 % 0,00 % Recoil initial
Mean Recoil 6,00 % 5,00 % 4,52 % 5,18 % Mean recoil after 3 deployement. 4,00 % 3,00 % 2,00 % 1,34 % 1,41 % 2,21 % 2,24 % 3,00 % 3,14 % 3,49 % 1,00 % 0,00 % Recoil moyen Mean Recoil < initial Recoil (except for Palmaz stent)
Foreshortening 50,00 % 45,00 % 45,18 % 40,00 % 35,00 % 30,00 % 25,00 % 20,00 % 15,00 % 10,00 % 5,00 % 6,06 % 9,92 % 13,76 % 14,15 % 14,40 % 14,92 % 16,06 % 18,52 % 0,00 % Foreshortening
Foreshortening 50,00 % 45,00 % 40,00 % 35,00 % 30,00 % 25,00 % 10% : Minus 0.5 cm in lenght for a 45-50 mm stent! 15% : Minus 0.75 cm in lenght for a 45-50 mm stent! 45,18 % 20,00 % 15,00 % 10,00 % 5,00 % 6,06 % 9,92 % 13,76 % 14,15 % 14,40 % 14,92 % 16,06 % 18,52 % 0,00 % Foreshortening
Foreshortening 50,00 % 45,00 % 40,00 % 35,00 % 30,00 % 25,00 % Valeo could be open until 18 mm but should it be (nominal diameter 6-10 mm) 45,18 % 20,00 % 15,00 % 10,00 % 5,00 % 6,06 % 9,92 % 13,76 % 14,15 % 14,40 % 14,92 % 16,06 % 18,52 % 0,00 % Foreshortening
Mechanical tests Recoil and foreshortening Averall compression Overall Radial Force Local compression Segmental Radial Force Longitudinal compression
Overall compression between two parallel plates Determination of the radial force to develop a diametrical reduction of 60% Stent structure Folding Axis
Overall compression between two parallel plates 1400,0 g 1200,0 g 1188,8 g 1000,0 g 996,1 g 908,200 g 800,0 g 600,0 g 694,3 g 667,1 g 586,9 g 558,7 g 538,2 g 460,7 g 400,0 g 200,0 g 0,0 g CP Stent 55mm Palmaz IntraStent DoubleStrut IntraStentMAX IntraStent MEGA CCP Stent 28mm AndraStent XXL Valéo AndraStent XL Force appliquée à 60% de réduction diamétrale There is a relationship between required force and stent s lenght
Overall compression between two parallel plates 40,00 35,00 30,00 31,96 30,58 30,16 29,50 28,45 27,61 25,00 25,22 25,12 22,89 20,00 15,00 15,27 10,00 5,00 0,00 Ratio Force/Lenght Low resistance of intrastent DoubleStrut Ratio (g/mm de stent) Ratio Force _ appliquée longueur_ stent
Overall compression between two parallel plates 40,00 35,00 30,00 31,96 30,58 30,16 29,50 28,45 27,61 25,00 25,22 25,12 22,89 20,00 15,00 15,27 10,00 5,00 0,00 Ratio Force/Lenght Low resistance of intrastent DoubleStrut Ratio (g/mm de stent) Ratio Force _ appliquée longueur_ stent
Overall compression between two parallel plates 40,00 35,00 30,00 31,96 30,58 30,16 29,50 28,45 27,61 25,00 25,22 25,12 22,89 20,00 15,00 15,27 10,00 5,00 0,00 Ratio Force/Lenght Low resistance of intrastent DoubleStrut Ratio (g/mm de stent) Ratio Force _ appliquée longueur_ stent
Overall compression between two parallel plates 40,00 35,00 30,00 31,96 30,58 30,16 29,50 28,45 27,61 25,00 25,22 25,12 22,89 20,00 15,00 15,27 10,00 5,00 0,00 Ratio Force/Lenght Low resistance of intrastent DoubleStrut Ratio (g/mm de stent) Ratio Force _ appliquée longueur_ stent
Determination of the radial force developed locally to 60% of diameter reduction. Local compression
Local compression Stents classification according to the cell resistance to the applied stress 600,0 g 528,3 g 500,0 g 446,1 g 445,0 g 400,0 g 300,0 g 338,0 g 337,5 g 319,4 g 317,7 g 279,1 g 200,0 g 219,1 g 201,4 g 100,0 g 0,0 g Force à 60% de réduction diamétrale 29
Longitudinal reduction of 50% of the original length Longitudinal Compression
Longitudinal Compression 3500,0 g 3000,0 g 2500,0 g 2000,0 g 2868,8 g E 2162,8 g 2117,9 g 1478,3 g E : elastic deformation of the stent E 1500,0 g 1304,8 g 1000,0 g 500,0 g 0,0 g 987,4 g E E 208,5 g 167,2 g E E 71,8 g 62,5 g Force enregistrée à 1 Palmaz, CCP Stent 16mm, CCP Stent 28, CP Stent 55mm : destructurations
Take home messages AndraStent XL : Important recoil and foreshorteningimportant but a good radial force : Short stenosis requiring a good radial force. Curves AndraStent XXL : Important recoil but low foreshortening and an excellent radial force : Recommended. Curves Valéo : Small recoil at 18 mm but very high foreshortening and as a consequence an excellent radial force : should we use it at 18 mm? CP ou CCP stent : Important recoil and foreshortening but a good radial force, intermediate recoil and radial force with important foreshortening (15%) «Classical lesion» without significant curve» Palmaz : The worst recoil, important foreshortening (10%), correct radial force «Classical lesion» without significant curve» IntraStent Mega and Max LD Stent : Low recoil, 13% foreshortening, good radial force «Classical lesion requiring a low recoil and good radial force» IntraStent DoubleStrut LD Stent : No recoil but the lower radial force :» «coarcation of the young in a curve»
AndraStent XL : Important recoil and important foreshortening but a good radial force : Short stenosis requiring a good radial force, curves.
Valéo : Small recoil at 18 mm but very high foreshortening and as a consequence an excellent radial force : should we use it at 18 mm?
CP ou CCP stent : Important recoil and foreshortening but a good radial force, intermediate recoil and radial force with important foreshortening (15%) «Classical lesion» without significant curve
Study limitations n=2 Ex vivo manipulations Ongoing study BVS Bench Testing Appearances are Sometimes Deceptive
Thank you for your attention
Bibliographie Analyseur de Texture TA.HD Plus www.texturetechnologies.com Organisation internationale de normalisation. Implants cardiovasculaires Dispositifs endovasculaires Partie 2 : endoprothèses vasculaires. Genève: ISO, 2013. 20p. Norme internationale ISO 25539-2 :2013 Barragan P, Rieu R, Garitey V, Roquebert PO, Sainsous J, Silvestri M, Bayet G. Elastic recoil of coronary stent: A comparative analysis. Catheter Cardiovasc Interv. 2000 ; 50(1):112-9. Choi H, Joo SM, Kim HK, Shin JH, Hwang MH, Choi J et al. A comparative reliability and performance study of different stent designs in terms of mechanical properties: foreshortening, recoil, radial force, and flexibility. Artif. Organs 2013;37(4):368-79. Ormiston J, Webber B, White J, Ubod B, Webster M. Point compression and stent longitudinal deformation: a novel clinically-relevant bench tests comparing 6 contemporary stent designs. EuroIntervention 2013. doi: 10.1161/CIRCINTERVENTIONS.113.000621 Leibundgut G, Gick M, Toma A, Valina C, Löffelhardt N, Büttner HJ, Neumann F-J. Longitudinal compression of the platinum-chromium everolimus-eluting stent during coronary implantation: Predisposing mechanical properties, incidence, and predictors in a large patient cohort. Catheter Cardiovasc. Interv. 2013; 81(5):e206 214. Schwartz RS, Huber KC, Murphy JG, Edwards WD, Camrud AR, Vlietstra RE, Holmes DR. Restenosis and the Proportional Neointimal Response to Coronary Artery Injury: Results in a Porcine Model. J Am Coll Cardiol. 1992 ;19(2):267-74 Illustration coeur : www.ikonet.com
PKP (POT, Kissing, final POT) Absrorb Final result very similar to PSP Good result on Main branch Bench B Bench A