`
`Edwards Lifesciences v. Boston Scientific
`U.S. Patent No. 6,915,560
`IPR2017-00072 EX. 2001
`
`
`
`© Martin Dunitz Ltd 2000
`
`First published in the United Kingdom in 1997 by J
`Martin Dunitz Ltd
`
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`Second Edition 1998
`
`Reprinted 1998
`Third Edition 2000‘
`
`p
`
`‘Reprinted 2000
`
`All rights reserved. No part of this publication may be reproduced, stored in a retrieval system,
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`Copyright Licensing Agency, 33-34 Alfred Place, London WC1 E 7DP. ‘
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`A CIP catalogue record for this book is available from the British Library
`
`ISBN 1 85317 802 - 0
`
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`Page 2 of 16
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`
`34. THE NIR AND NIROYAL
`CORONARY STENTS
`
`Medina]/$c1'Med Life S}/Steins, Maple Grove,"/MN, USA
`
`' Kobi Richter, Yaron Almagor and Martin Leon
`
`Description
`
`A_
`.
`General
`The NIR Stent was developed based on many physicians’ ‘wish list’ for new
`functional‘ features in order to overcome shortcomings of first generation
`devices. The two most important features of the coronary stent are basic to its
`use: the radial force with which it supports the vessel, and its flexibility, one of A
`the major determinants of its trackability into the target lesion before deploy— .
`ment. The basic contradiction between flexible structure that enable good track-
`ability and rigid structure that result in optimal support, brought the developers
`of first generation stents to select one property while compromising on the
`other. A typical comparison of features resulting from that forced decision is:
`..a
`
`
`
`Radial supportStent Flexibility
`Palrnaz—Schatz
`High
`Low
`
`
`
`.
`
`Gianturco—Roubin
`
`Low
`
`High
`
`Our primary goal in designing the NIR Stent was to «overcome this compromise
`by a new design for the stent, with a secondary goal to optimize other clinically
`important features.
`
`Transforming geometry.
`A design goal was defined noticing that the two features are not required simul-
`taneously, but rather at two mutually exclusive time slices.
`~' Flexibility is required only during insertion and until deployment of the stent
`at the target lesion.
`Rigidity is required to supply long term support to the vessel wall only from
`the moment of deployment and on.
`'
`g
`It was thus defined that the desired geometry should be flexiblevupon insertion
`and will change after deployment to be rigid upon expansion.
`'
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`Page 3 of 16
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`K031 RICHTER, YARON ALMAGOR AND MARTIN LEON
`\
`
`Figure 34.1: The NIR stent before expansion, showing the djferentially
`elongating cells. The cell inside the curve is shorter than its counterpart
`outside the curve, as shown by the converging lines at their border. This
`feature is enabled by the Vertical loop component of the cell that opens on
`the outside cell (A) and closes on the inside cell (B).
`
`Trackability and flexibility
`. The flexibility of a stent, a long stent especially, is a major parameter in deter-
`mining its trackability into the naturally curved and tortuous anatomy of diseased
`coronary arteries. In order to track into such anatomies the stent on its deliv~
`ery system has to curve around corners or it will latch on the opposing vessel
`wall. The flexibility depends on the ability of the stent to elongate differentially
`such that the stent wall outside of the curve be longer than the wall inside the
`curve. Inability or high resistance to such differential elongation will not allow
`the stent to flex. The design of the NIR stent is based on uniform cells each of
`which is capable of elongating or foreshortening as demonstrated in ‘Figure 34.1.
`Other important features that facilitate the trackability of the stent arez,
`
`. The stent has no ‘free internal points’ loops or ends internal to the tubular
`structure that are not connected longitudinally to their neighbors and thus
`can flare" out and generate internal ridges that will latch on plaque surface
`upon insertion (Figure 34.2).
`2. The stent has a very‘ low profile and crirnps easily and securely on the balloon
`
`282
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`Page 4 of 16
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`THE NiR AND NIROYAL CORONARY ‘STEN-TS
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`_ ‘J
`
`owing to the original structure with struts slightly open (see Figure 34.1)
`that leaves a lot of room for crimping until struts touch each other (see Figure‘
`A 34.2).
`V
`'
`V
`3. Most of the struts are along the insertion direction of the stent and thus. will
`not catch on plaque the way ai typical coiled stent would (see Figure 34.2).
`
`Page 5 of 16
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`Page 6 of16
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`Page 6 of 16
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`E
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`THE NIR AND NIROYAL CORONARY S'l'ENTS
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`Rigidity and radial support
`During expansion of the stent in the target lesion the geometry of the basic
`uniform "cell changes (Figure 34.3) in a way that will cause the vertical loops of
`the cell to align with the horizontal loops and form a diamond—like cell with
`straight struts at about 45°.
`-The resulting diamond-like mesh with interlinked struts is much stronger and
`more ri id than an structure without such interlinkin . At this oint in time
`3
`Y
`3
`P
`the stent loses its flexibility, but this lost feature is‘ no‘ longer important since
`the stent is not required to move anywhere.
`
`Important features of the expanded NIR stent
`1. The uniform cellular design allows for a continuous supportlwithout
`gaps unlike articulations in other stents, or ‘increased distance between
`struts that may occur in stents whose struts are not interlinked and
`move relative to each other.
`'
`. The relatively small cells decreased the chance .for tissue prolapse and
`plaque scale protrusion_ into the lumen. The smaller cells made of
`shorter struts provide for higher radial resistance and decreased wall
`trauma by decreasing the local pressure on the wall. The number of
`circumferential struts in the NIR stent is 18 and in the-Palrnaz—Schatzv
`8,‘thus at an equal total radial force the local force applied by each strut
`is less than one half in the NIR stent.
`. The differential elongation of the vertical loops of the cells, responsible
`for the flexibility upon insertion, allows for conformance of the stent
`‘with the_ vessel curvature such that the rigid expanded stent does not
`straighten the vessel and does not create a sharp
`at the interface
`between the stented area and the unstented area. Such a kink created
`by other rigid stents (e.g. Palmaz——Schatz may cause turbulence and
`applies excessive local pressure that accounts for a higher restenosis rate
`at the stent ends. That feature of conformance with vessel curvature (see
`Figure 34.3) allows also for multiple stenting of long segments required
`in many cases of diffuse disease and generates a smooth conformed
`reconstructed section.
`4
`. Most‘ stents available on the market foreshorten upon expansion by
`varied amounts owing to the ‘change in diameter of the stent. The
`combination of vertical
`loops and horizontal ‘loops in the NIR cell
`results in minimized foreshortening based on the fact that upon expan—'
`sion the horizontal loops foreshorten but the vertical loops elongate and
`compensate for the foreshorteping thus keeping the total length of the
`cell unchanged (Figure 34-._4-).
`
`Page 7 of 16
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`
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`K031 RICHTER, YARON ALMAGOR AND MARTIN LEON
`I
`
`Figure 34.4: While the
`cell expands the
`horizontal loops
`foreshorten and the
`vertical loops elongate to
`leave the total length of
`the cell unchanged.
`
`Case example
`The following is an example of a case treated with the NIR stent. It is from the
`first pilot study performed in the Centro Cuore in Milan on july 1995, by Drs
`Colombo, Almagor and DiMario. »
`
`"Case 1:
`
`A 32—mm stent was inserted into a very tortuous RCA using a right judldns guiding
`catheter. In spite of the suboptimal support the stent tracked into the vessel
`smoothly to yield a good result in a very short procedure involving. a single stent.
`
`Conclusion
`
`The NIR stent is a second generation "stem with improved functional features,
`_ as demonstrated by its geometry clinical results.
`
`Figure 3455: A 32—mm NIR stem was inserted into a vezj/tortuous RCA,
`demonstrating the t1'acleah1'l1'ty of the stem. The result on the right would require at
`least two stems of other designs.
`'
`
`286
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`Page 8 of 16
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`
`
`THE NIR AND NIROYAL CORONARY STENTS
`
`_
`New features available
`Two main new features have been introduced to the coronary market since the
`first edition. A pre—mounted system and the NIROYAL gold plated radio—opaque
`stent. The pre—mounted system, the NIR PRIMOTM, features the NIRTM PRIMOTM '
`stent pre—mour'1ted on a modified VIVA PRIMOTM balloon catheter from SciMED.
`The pre—mounted system saves time as crimping is not required and increases
`safety by a better and more consistent crimping. The system also features a short
`ring of plastic material inserted under the balloon in front of the stent. This
`increases the diameter of the balloon in front of the stent and creates a ‘dam’
`that prevents the stent from slipping off the balloon (see Figure 34.6).
`The NIROYAL stent is a NIR stent plated with gold (see Figure 34.7) to
`increase its radio-opacity. The stent has indeed a drastically improved radio-
`opacity (see Figure 34.8) that allows its visualization before and after expansion.
`The radio—opacity ‘of the NIROYAL was, nevertheless, designed such that the
`stent will be visible but will not hide angiographic details after its deployment
`(see Figures 34.9—34-.16). The radio—opa_city of the NIROYAL is important for ‘
`positioning judgment by the physician, and especially in cases of multiple stents
`for judgment of overlap, and in bifurcation and ostial stenting where relative
`position is critical.
`
`287
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`Page 9 of 16
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`Page 10 of16
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`Page 10 of 16
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`
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`THE NIR_AND NIROYAL CORONARY STENTS
`
`Case example
`The following is an example of a case treated with new NIR stents. It is a case
`A of a bifurcation stenting performed with the NIROYAL.
`
`Case 1:
`A lesionuin the LAD involving an ostial lesion in the first diagonal was selected
`for treatment (Figure 34.9). A 32 rnma long NIROYAL was placed in the LAD
`across the bifurcation of the diagonal (Figures 34.10 and 34-.(1_.1). A second, 9 mm
`long NIROYAL was inserted into the diagonal through the cells of the LAD stent
`(Figures 34.12 and 34.13). The diagonal stent left a gap at the ostium uncov-
`ered (Figure 34.14) and a third NIROYAL was placed to bridge the gap (Figure
`34.15) to yield a good final result (Figure 34.16).
`-.
`-
`1
`
`Figure 34.9: A lesion in the I.AD".(red arrow) overlaps an ostial lesion in
`the diagonal (yellow arrow).
`"
`«
`'
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`-
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`THE NIR AND NIROYALI CORONARY ST-ENTS _
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`Figure 34.16: Fina] result demonstrating that the NIROYAL does not hide
`angiographic details.
`'
`-
`
`References
`
`1.
`
`Almagor Y, Feld S‘, Kiemeneij F et al, for the FINESS Trial Investigators. First
`international new intravascular rigid-flex endovascular stent study (FINESS):
`clinical and angiographic results after elective and urgent stent implantation. ] Am
`I
`Coll Cardiol 1997;30:84-7-54-.
`V
`
`Almagor Y, Feld S, Kiemeneij F et al. First international new intravascular rigid-
`flex endovascular stent study: angiographic results and six month clinical follow-
`up. Eur Heart] 1997;l8(suppl):156.
`_Di Mario C, Reirners B, Almagor Y et al. Procedural and follow—up results with
`a new balloon expandable stent in unselected lesions. Heart 1998;79:234—41.
`
`Zheng H, Corcos T, Favereau X, Pentousis D, Guérin Y, Ouzan ]. Preliminary
`experience with the NIR coronary stent. Catheter Cardiovasc Diagn
`l998;43:l53—58.
`
`V Lau KW, He Q, Ding ZP, Quek S, johan A. Early experience with the NIR
`intracoronary stent. Am j Cardiol 1998;81:927—29.
`
`Chevalier B, Lefevre T, Meyer P et al. French registry of seven cells NIRstent
`implantation in .<_2.5 mm coronary‘ arteries [abstract]. Circulation
`1997;96(suppl) :I-274.
`
`Page 15 of 16
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`Lansky A], Popma ]], Mehran R et al. Late quantitative angiographic results after
`NIR stent use: results from the NIRVANA randomized "trial and registries
`[abstract]. j Am Col] Catdiol 1998;31(suupl):8OA.
`
`Baim DS. Acute and 30-day clinical results of the NIRVANA Trial [abstract].
`Circulation 1997;96(suppl):I-S94-.
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