Journal of the American College of Cardiology
`© 2002 by the American College of Cardiology Foundation
`Published by Elsevier Science Inc.
`
`STATE-OF-THE-ART PAPER
`
`Vol. 40, No. 6, 2002
`ISSN 0735-1097/02/$22.00
`PII S0735-1097(02)02123-X
`
`Selection of Coronary Stents
`Antonio Colombo, MD, FACC,* Goran Stankovic, MD,* Jeffrey W. Moses, MD, FACC†
`Milan, Italy; and New York, New York
`
`In clinical practice, the operator must decide which stent is most appropriate for the patient.
`This article focuses on the features of stent design that make a specific stent more or less
`suitable for a particular type of lesion or anatomy: the “average” coronary lesion, the lesion
`situated on a curve, the ostial lesion, the bifurcational lesion, the lesion located at the left main
`stem, the calcified lesion, the chronic total occlusion, the small vessel, the saphenous vein
`graft, acute or threatened vessel closure, and special situations such as coronary aneurysms and
`perforations.
`(J Am Coll Cardiol 2002;40:1021–33) © 2002 by the American College of
`Cardiology Foundation
`
`The implantation of coronary stents is an integral part of
`most interventional procedures for percutaneous revascular-
`ization. The wide acceptance of coronary stenting was based
`on the results of the BElgian NEtherlands STENT (BE-
`NESTENT)
`(1) and the STent REStenosis Study
`(STRESS) (2) trials and was facilitated by the elimination
`of anticoagulant therapy after stent implantation (3–5).
`The growing use of stents has stimulated the introduction
`of a number of different stent designs. Table 1 illustrates the
`characteristics of most of the stents available in 2002. The
`rapid increase in the number of designs makes any list
`quickly outdated. Some stent designs are similar, whereas
`others differ significantly. There are many reasons why
`different designs have been proposed. Besides the legal
`requirement to overcome a specific patent, there are con-
`cepts of physiologic mechanisms that stimulated inventors
`to introduce new designs. A primary concern of stent
`development was the need to increase flexibility to facilitate
`safe delivery. Manufacturers try to achieve this goal without
`compromising radial support and lesion coverage. Another
`element important for optimizing the clinical utility of a
`stent is its radiologic visibility.
`Many of the engineering considerations in stent design
`were adopted to improve the global acceptability of the
`device, rather than making a stent design for a specific type
`of coronary lesion. In clinical practice, the operator must
`decide which stent is most appropriate for the patient. This
`article focuses on the features of stent design that make a
`specific stent more or less suitable for a particular type of
`lesion or anatomy.
`Types of stents. Stents can be classified according to their
`mechanism of expansion (self-expanding or balloon-
`expandable), their composition (stainless steel, cobalt-based
`alloy, tantalum, nitinol, inert coating, active coating, or
`biodegradable), and their design (mesh structure, coil,
`slotted tube, ring, multi-design, or custom design) (Table
`
`From the *Columbus Hospital, Milan, Italy; and †Lenox Hill Hospital, New York,
`New York.
`Manuscript received February 12, 2002; revised manuscript received March 29,
`2002, accepted April 17, 2002.
`
`1). According to the manufacturers, all stents are suitable for
`implantation in native coronary arteries of the appropriate
`size. Some stents are approved for implantation in vein
`grafts. Few stents are specifically designed to be implanted
`in a particular lesion. The absolute or relative contraindica-
`tions to the use of stents apply to stents in general and not
`to a specific stent. Possible exceptions are the Multilink
`Ultra Stent (Guidant, Temecula, California), which is
`designed for vein graft implantation with a nine-cell design,
`by contrast with the six-cell design of the Multilink Tetra.
`The JoMed polytetrafluoroethylene (PTFE)-covered stent
`(JoMed, Rangendingen, Germany) is specifically made for
`uncommon applications such as coronary ruptures, aneu-
`rysms, and degenerated saphenous vein grafts.
`Different characteristics such as strut thickness, metal to
`artery ratio, degree of radiopacity, degree of foreshortening,
`and recoil of many currently used stents are shown in Table
`1. All stents are now available premounted on a dedicated
`delivery system. The capacity of a stent to span a lesion
`depends not only on the diameter of the crimped stent
`(Table 2), but also on the amount of friction of the delivery
`system and stent, flaring of the distal struts during interac-
`tion with the lesion, flexibility of the stent and of the
`delivery balloon, and pushability of the delivery system. It is
`not surprising to observe a stent with a larger crossing
`profile cross a lesion easier than a narrower stent with less
`flexibility.
`Two interesting findings came from the stent versus stent
`randomized trials: 1) the GR-II stent (Cook, Bloomington,
`Indiana) proved clearly inferior—as far as early complica-
`tions, binary restenosis, and target lesion revascularization
`rate—to the Palmaz-Schatz stent (Cordis, a Johnson &
`Johnson Company, Warren, New Jersey) (6); and 2) the
`performance of the various other stents and the associated
`clinical outcome were not different from the Palmaz-Schatz
`stent. The slightly better deliverability of some stents
`compared with the Palmaz-Schatz stent, as seen in some of
`equivalency trials, has now only historical value. Stents used
`nowadays perform significantly better than any of the
`early-generation devices.
`
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`1022
`
`Colombo etal.
`Stent Selection
`
`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`Abbreviations and Acronyms
`IVUS ⫽ intravascular ultrasound
`PTFE ⫽ polytetrafluoroethylene
`PTCA ⫽ percutaneous transluminal coronary angioplasty
`
`Based on our experience with multiple stent systems, we
`submit the following observations concerning the applica-
`tion of different stents for specific lesion subsets.
`The “average” coronary lesion. Stents were initially indi-
`cated for proximal, non-angulated lesions, whereas subse-
`quent generation stents were developed for lesions of
`tortuous anatomy and complex situations. Some stents are
`more flexible than others or have a smaller profile and
`therefore are more deliverable. These extra features become
`necessary only in selected situations. Most stents currently
`available are suitable for the majority of coronary lesions,
`with some exceptions.
`The stents to be used in the “average” coronary lesion are
`the new slotted, tubular stents and some new designs of ring
`stents.
`The primary goal for stenting most coronary lesions is to
`achieve the optimal
`lumen cross-sectional area without
`traumatizing the artery. Currently, the achievement of a
`large final lumen diameter is the most secure means of
`limiting restenosis (7). Other appropriate concerns for stent
`choice are adequate lesion coverage, minimal recoil, and
`limited plaque prolapse. In addition, because stent length is
`an independent predictor of restenosis, it is preferable to
`avoid the use of excessive metal (8,9).
`The Palmaz-Schatz stent led the way but now has passed
`the baton to the BxVelocity (Cordis), as demonstrated in
`the Very Early Nimopidine Use in Stroke (VENUS) trial, a
`multicenter registry of the Cordis BxVelocity stent (10). It
`is likely that the BxVelocity stent will be replaced by the
`sirolimus-coated BxVelocity (11,12). The BxVelocity stent
`is applicable for everyday use, and there are only a few
`conditions in which this stent may not be satisfactory. The
`BxVelocity stent is available in three different patterns of
`cells according to the vessel size in which the stent will be
`implanted: six cells for vessels up to 3 mm, seven cells for
`vessels up to 4 mm, and nine cells for vessels up to 5 mm.
`The new version, BxSonic (Cordis), has the same stent
`mounted on an improved delivery system that is compatible
`with the 5F guiding catheter (lower profile proximal hypo-
`tube shaft, 1.9F vs. 2.6F shaft of the BxVelocity, and
`0.5-mm balloon overhang on each side).
`The heparin-coated Palmaz-Schatz stent had a low
`incidence of subacute stent thrombosis, with only five
`thrombotic events (0.4%) in 1,169 patients treated with this
`stent in the following trials: the BENESTENT II pilot
`study (13), BENESTENT II randomized study (14), and
`the Total Occlusion Study of CAnada (TOSCA) (15), as
`well as in two protocols involving patients with acute
`myocardial infarction: the stenting in Primary Angioplasty
`
`in Myocardial Infarction (PAMI) pilot study (16) and the
`stent PAMI randomized study (17). A multicenter feasibil-
`ity study (use of the Hepacoat BxVelocity stent and an
`antithrOmbotic regimen of asPirin alonE [HOPE]) is
`under way to examine the safety of the heparin-coated
`BxVelocity stent (Hepacoat, Cordis) in “low-risk” patients
`treated with antiplatelet therapy consisting of only aspirin.
`The initial results in 202 patients showed no acute stent
`thrombosis and a rate of 1% of subacute thrombosis (one
`patient with thrombocytosis and one with post-trauma)
`(18).
`The Multilink Tetra stent (Guidant) has functional
`characteristics that are similar to the BxVelocity stent. The
`overall performance of these two stents is excellent, with
`only selected situations where the Tetra appears to be more
`deliverable. A unique feature of the Tetra delivery system
`(similar to the Ultra) is its shaft length of 143 cm, which is
`3 cm longer than the BxVelocity stent, whereas all the other
`delivery systems are 138 or 135 cm long. Compared with
`the Multilink Tetra stent,
`the Multilink Penta stent
`(Guidant) has a modified link pattern, which improves
`flexibility and scaffolding and maintains side-branch access
`with the possibility to expand the cell toward the side
`branch up to 4 mm in diameter.
`The careful observer may find more stent-to-vessel con-
`formability with the Tetra stent, but no one knows whether
`this feature has any clinical consequences. Preserving the
`original shear stress pattern of the arterial segment may
`lower the amount of tissue hyperplasia (19).
`The NIR stent (Medinol, Jerusalem, Israel; and Scimed,
`Boston Scientific, Maple Grove, Minnesota), with its new
`“sox” delivery system,
`is another important stent to be
`considered for the “average” lesion. The NIR stent provides
`excellent plaque coverage, which may be an advantage in
`lesions prone to plaque prolapse. Plaque may prolapse
`between stent struts in large vessels with a reference diam-
`eter ⱖ4 mm. The NIR stent is available with a seven-cell or
`nine-cell structure, which improves plaque support in large
`vessels, including saphenous vein grafts. The sox delivery
`system protects the stent while negotiating through calcified
`lesion or crossing another stent. These features are unique to
`this type of stent delivery system.
`The performance of this stent was evaluated against the
`Palmaz-Schatz stent in the NIR Vascular Advanced North
`American (NIRVANA) trial randomized study (20). This
`trial reported a follow-up restenosis rate of 19.3% for the
`NIR stent and 22.4% for the Palmaz-Schatz stent. The
`moderate rigidity of the NIR stent discourages its use
`through tortuous segments and for lesions located at a
`severe bend. Because the NIR stent becomes rigid on
`deployment, this stent may produce a hinge effect that is
`associated with an increase in restenosis (21). Figure 1
`demonstrates the hinge effect caused by the NIR stent. This
`lesion restenosed four months later at the distal extremity of
`the stent (Fig. 2). The operator should foresee this possi-
`
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`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`Colombo et al.
`Stent Selection
`
`1023
`
`bility and select a more flexible type of stent in lesions with
`a small radius of curvature.
`The positive features of these three stents are also related
`to the delivery balloon: 1) there is now near perfect
`retention, which has eliminated the problem of stent loss; 2)
`there is minimal overhang of the delivery balloon from the
`stent, which limits trauma and the risk of peri-stent dissec-
`tion; and 3) there is low compliance, which assures a more
`homogeneous stent deployment (Fig. 3).
`The beStent (Medtronic AVE, Minneapolis, Minnesota)
`and now the beStent 2, with a closer strut design, are other
`stents to consider. The unique feature of this stent is the
`presence of proximal and distal gold markers that allow very
`precise placement. Another positive feature of the beStent,
`but not the beStent 2, is the presence of a large or open cell
`design that facilitates access to side branches.
`The Biodivysio stent (Biocompatibles, Galway, Ireland)
`is another sturdy device with optimal scaffolding that can be
`considered for most lesions. This stent is available also with
`an open-cell design that is suitable for lesions involving the
`origin of side branches. Compared with the open-cell
`design, the added support design has an extra strut between
`interlocking arrowheads, which provides greater coverage
`for lesions that require additional support.
`The Biodivysio stent was recently evaluated against the
`Duet stent (Guidant) in a randomized trial (bioDIvysio
`STent IN randomized Control Trial [DISTINCT]). Both
`stents showed an excellent low restenosis rate of 19% in
`selected favorable lesions. The standard Biodivysio stent
`delivery system appears to be more rigid compared with
`other stents and is not ideal for very tortuous arteries. New
`versions of the delivery system will soon be released to
`overcome this potential
`limitation. The availability of a
`small-vessel design with this stent, which is very trackable
`and has a low profile, should be kept in mind when
`confronted with complex anatomy. A unique feature of the
`Biodivysio family is their phosphorylcholine coating, which
`lowers platelet adhesion to the stent struts and may be used
`as a platform for drug delivery.
`Among the ring stents, the new S7 (Medtronic AVE)
`provides more plaque coverage than the S670 and has an
`angiographic appearance very similar to the slotted, tubular
`stents. This stent is appropriate for most lesions. In addi-
`tion, the flexibility, conformability, and lower friction typ-
`ical of the S7 ring design improves deliverability in complex
`anatomies or when passing through a stent. An important
`characteristic of the AVE delivery system is minimal bal-
`loon overhang (Fig. 3).
`Among the stainless-steel stents with a good track record,
`the family of stents from PURA (Devon Medical, Ham-
`burg, Germany) and the V-Flex plus (Cook) should be
`mentioned.
`To make the choice more difficult, the interventionist is
`confronted with other excellent stents such as the Sorin
`Sirius Carbostent (Sorin Biomedica Cardio, Saluggia, Italy),
`with its recently refined delivery system (Sorin Syncro
`
`in difficult
`Carbostent). This stent performs quite well
`anatomies and lesions, has platinum end markers, and is
`covered with a thin layer of turbostratic carbon with the
`intent to decrease its interaction with platelets. A recent
`registry report showing a restenosis rate of 11% and a
`bimodal distribution of
`the loss index (22) raises the
`possibility of enhanced biocompatibility of the carbon-
`coated stent for subjects with an allergy to metal compo-
`nents present in stainless steel (23). At least four other
`carbon-coated stents are currently available in Europe: the
`BioDiamond (Plasma Chem, Mainz, Germany), the Dia-
`mond Flex (Phytis, Dreieich, Germany), the MAC carbon
`stent (AMG, Raesfeld-Erle, Germany), and the Tenax
`(Biotronik, Berlin, Germany). Randomized trials are in
`progress to test the hypothesis that these inertly coated
`stents may have advantages over the stainless-steel stents.
`Lesions situated on a curve (>90°) or immediately fol-
`lowed by a curve. Changing the natural conformation of a
`coronary vessel may have an unfavorable effect on flow
`dynamics and increase the risk of adverse events during
`follow-up (24).
`For this reason, we prefer stents that conform to the
`longitudinal profile of the vessel without producing plaque
`prolapse in the curved segment. The traditional ring design,
`such as the S670, is quite conformable but may allow too
`much plaque protrusion when opened in a curved segment.
`In this respect, the new S7 is a significant improvement.
`Slotted, tubular stents with thin struts are also conformable
`(PURA AS and AL 0.07, 0.075-mm beStent, 0.075-mm
`Sorin Carbostent, 0.08-mm Tenax, 0.09-mm Biodivysio,
`and 0.09-mm JoStent). Strut thickness is not the only
`variable that may affect conformability; the complete stent
`design may be more important. For example, the NIR stent,
`which is thinner (0.1 mm) than the BxVelocity (0.14 mm),
`has lower conformability. The Tetra and Penta stents have
`variable strut thicknesses (0.091– 0.124 mm), with excellent
`conformability. The NIRflex, the new version of the NIR
`stent, also has excellent conformability.
`Ostial lesions. Ostial lesions are classified as either aorto-
`ostial or coronary-ostial. For aorto-ostial
`lesions,
`the
`slotted-tube design, preferably with strong radial support,
`low recoil, and radiologic visibility, is the most appropriate
`one (25). New ring designs such as the S670 and S7 are also
`appropriate in this setting.
`The recent availability of stents with end markers may
`improve precise positioning. These stents have thin struts,
`so our preference is to implant them only in coronary-ostial
`rather than aorto-ostial locations. The strong elastic recoil
`inherent to the aorta favors the use of thicker struts to
`provide greater resistance when dealing with lesions involv-
`ing the true coronary ostia or the aortic insertion of a
`saphenous vein graft.
`When considering the gold-plated NIR Royal for an
`aorto-ostial lesion, the operator must balance its advantage
`of better visibility and more precise positioning with its
`disadvantage of having a higher angiographic restenosis rate
`
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`1024
`
`Colombo etal.
`Stent Selection
`
`Table 1. Stent Engineering Data
`
`Product
`
`Manufacturer
`
`Structure
`
`Material
`
`Strut (Wire)
`Thickness
`(mm)
`
`Metal/Artery
`(%)*
`
`Recoil
`(%)
`
`Shortening
`(%)
`
`Radiopacity Markers
`
`Lengths (mm)
`
`Diameters (mm)
`
`Sinusoidal ring
`Medtronic
`AVE S670
`Sinusoidal ring
`Medtronic
`AVE S7
`Slotted tube
`Medtronic
`beStent 2
`Slotted tube
`Biocompatibles
`Biodivysio AS
`Slotted tube
`Biocompatibles
`Biodivysio OC
`BxVelocity/Hepacoat Cordis, Johnson & Johnson Slotted tube
`
`0.127
`Stainless steel
`0.102
`Stainless steel
`Stainless steel 0.085–0.095
`Stainless steel
`0.091
`Stainless steel
`0.091
`Stainless steel
`0.14
`
`BxSonic
`
`Cordis, Johnson & Johnson Slotted tube
`
`Stainless steel
`
`0.14
`
`Carbostent Sirius
`Carbostent Syncro
`Cook V-Flex
`Diamond Flex AS
`JoStent Flex
`
`JoStent Plus
`
`JoStent Graft
`
`Sorin
`Sorin
`Cook
`Phytis
`Jomed
`
`Jomed
`
`Jomed
`
`Slotted tube
`Slotted tube
`Slotted tube
`Slotted tube
`Slotted tube
`
`Stainless steel
`Stainless steel
`Stainless steel
`Stainless steel
`Stainless steel
`
`Slotted tube
`
`Stainless steel
`
`Slotted tube
`
`Stainless steel
`
`Boston Scientific
`LP Stent
`MAC Carbon Stent AMG
`
`Slotted tube
`Slotted tube
`
`Stainless steel
`Stainless steel
`
`0.075
`0.075
`0.07
`0.075
`0.09
`
`0.09
`
`0.20
`
`0.1
`0.085
`
`19
`17–23
`12–17
`19–25
`9–12
`15
`
`15
`
`12–17
`12–17
`15
`10–18
`16
`
`16
`
`100
`
`15
`8–15
`
`3
`2
`2
`2
`4
`2.5
`
`2.4
`
`3–5
`3–5
`21
`3–5
`4
`
`4
`
`2
`
`2
`3
`
`3
`3
`0
`4
`4
`1.7
`
`1.7
`
`0
`0
`0
`1
`5
`
`5
`
`3
`
`3–5
`1
`
`1
`
`Medium No
`Medium No
`Low
`Yes
`Low
`No
`Low
`No
`Medium No
`
`Medium No
`
`Low
`Low
`Low
`Low
`Low
`
`Low
`
`High
`
`Low
`Low
`
`High
`
`Yes
`Yes
`No
`No
`No
`
`No
`
`No
`
`No
`No
`
`No
`
`9, 12, 15, 19, 25
`9, 12, 15, 19, 25
`12, 16, 20, 24
`9, 12, 16, 20, 25
`9, 16, 26, 32
`
`9, 17, 27, 33
`
`9, 12, 16, 19, 26
`
`8, 12, 18, 24
`9, 13, 17, 22
`
`9, 12, 15, 18, 24, 30 3.0, 3.5, 4.0
`9, 12, 15, 18, 24, 30 3.0, 3.5, 4.0
`9, 12, 15, 18, 24, 30 2.5, 3.0, 3.5, 4.0
`11, 15
`3.0, 3.5, 4.0
`15, 18, 22, 28
`3.0, 3.5, 4.0
`8, 13, 18, 23, 28, 32 2.25, 2.5, 2.75, 3.0,
`3.5, 4.0, 4.5, 5.0
`8, 13, 18, 23, 28, 33 2.25, 2.5, 2.75, 3.0,
`3.5, 4.0
`2.5, 3.0, 3.5, 4.0
`2.5, 3.0, 3.5, 4.0
`2.5, 3.0, 3.5
`2.5, 3.0, 3.5, 4.0
`2.0, 2.5, 3.0, 3.5,
`4.0, 4.5
`2.0, 2.5, 3.0, 3.5,
`4.0, 4.5
`2.5, 3.0, 3.5, 4.0,
`4.5, 5.0
`2.5, 30, 3.5, 4.0
`2.0, 2.5, 3.0, 3.5,
`4.0, 4.5
`2.5, 2.75, 3.0, 3.5,
`4.0
`2.5, 2.75, 3.0, 3.5,
`4.0
`2.75, 3.0, 3.5, 4.0
`
`9, 12, 13, 15, 16,
`17, 19, 23
`8, 13, 18, 23, 28
`
`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`3.5, 4.0, 4.5, 5.0
`2.0, 2.5, 3.0, 3.5,
`4.0, 4.5, 5.0
`2.0, 2.5, 3.0, 3.5,
`4.0, 4.5, 5.0
`2.25, 2.5, 2.75, 3.0,
`3.5, 4.0, 4.5, 5.0
`3.0, 3.5, 4.0
`3.0, 3.5, 4.0, 4.5,
`5.0
`3.5, 4.0
`2.5, 3.0
`2.5, 3.0, 3.5, 4.0
`2.5, 3.0, 3.5, 4.0
`
`(continued)
`
`8, 13, 15, 18, 23,
`28, 33
`13, 18, 28, 38
`9, 16, 25, 32
`
`9, 16, 25, 32
`
`8, 12, 16, 20, 24,
`28, 32
`8, 9, 14, 18
`7, 15
`
`6, 10, 16, 24, 28
`6, 10, 16, 24, 28
`10, 15, 20, 25, 30
`10, 15, 20, 30
`
`1
`
`2–3
`
`2–3
`
`2
`3
`
`5
`
`5
`
`5
`2
`
`3
`3
`5
`5
`
`3–4
`
`3–4
`
`5
`3
`
`3
`
`5
`
`8
`1–5
`
`5
`7
`3
`5
`
`Medium No
`
`Medium No
`
`Medium No
`Low
`No
`
`High
`
`High
`
`No
`
`No
`
`Medium No
`Low
`No
`
`Low
`Low
`Low
`Low
`
`No
`No
`Yes
`No
`
`15–25
`11–18
`
`11–18
`
`11–17
`
`18
`10–15
`
`10–18
`10–18
`14–22
`18
`
`0.1
`
`0.132
`
`0.062
`0.12
`
`0.07
`0.07
`0.08
`0.08
`
`Megaflex Genius
`
`Eurocor
`
`Slotted tube
`
`Stainless steel
`
`0.12
`
`20
`
`Multilink Tetra
`
`Guidant
`
`Slotted tube
`
`Stainless steel
`
`0.091–0.124
`
`12–20
`
`Multilink Penta
`
`Guidant
`
`Slotted tube
`
`Stainless steel
`
`0.091–0.124
`
`12–16
`
`Multilink Ultra
`NIR, 7 cells and 9
`cells
`NIR Royal
`
`Express
`
`P-S 153
`PURA-A
`
`Stainless steel
`Slotted tube
`Guidant
`Medinol, Boston Scientific Multicell design Stainless steel
`
`0.127–0.101
`0.1
`
`Boston Scientific
`
`Medinol, Boston Scientific Multicell design Stainless steel,
`gold
`Multicell design Stainless steel,
`gold
`Stainless steel
`Stainless steel
`
`Cordis, Johnson & Johnson Slotted tube
`Devon
`Slotted tube
`
`PURA Vario AL
`PURA Vario AS
`Teneo Tenax-XR
`Tsunami
`Small-vessel stents
`
`Devon
`Devon
`Biotronik
`Terumo
`
`Slotted tube
`Slotted tube
`Slotted tube
`Slotted tube
`
`Stainless steel
`Stainless steel
`Stainless steel
`Stainless steel
`
`Page 4
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`

`Colombo et al.
`Stent Selection
`
`1025
`
`than the stainless-steel NIR (37.5% vs. 20.6%, p ⬍ 0.001),
`as reported in the NIR Ultimate Gold-Gilded Equivalency
`Trial (NUGGET) (26). Similar findings were reported with
`a gold-coated stent manufactured by a different company
`(27).
`For aorto-ostial lesions with a reference vessel size of ⱖ4
`mm in diameter, we have had a positive clinical experience
`with the BxVelocity, the nine-cell NIR, and the Ultra. All
`of these slotted-tube stents maintain good radial force, even
`when dilated to large diameters.
`Bifurcational lesions. When approaching a bifurcational
`lesion, it may be preferable to have a stent with large side
`openings between the struts that can easily permit passage of
`a balloon or second stent into the side branch. Figure 4
`shows several slotted-tube stents with the cross-sectional
`area of the cell following stent dilation and with the
`cross-sectional area of the same cell following the maximal
`opening of a balloon inflated across the cell into the side
`branch (28). Many slotted-tube stents are suitable for
`stenting a bifurcation, with the exception of the NIR stent.
`The closed-cell design of the NIR does not allow significant
`expansion of the opening toward the side branch, even after
`crossing and inflating a balloon. If the operator decides to
`use the NIR stent, the seven-cell design should be used
`instead of the nine-cell design.
`Another option is to use a stent with a large side opening,
`such as the Biodivysio open-cell design or the S670. The
`advantage of this decision is that the initial access to the side
`branch is facilitated. A possible disadvantage is incomplete
`prolapse of one strut toward the side branch following a
`“kissing” balloon dilation (i.e., dilating 2 balloons simulta-
`neously into both branches of a bifurcation). The concept of
`strut prolapse from the main branch toward the side branch
`has been pioneered by Dr. Marie Claude Morice and Dr.
`Tierry Lefevre and termed “stenting both branches with one
`stent.” When the design is very open, there is less possibility
`for a strut to straddle across the side branch. Slotted-tube
`stents that best demonstrate this feature are the beStent and
`Carbostent, but the BxVelocity and Tetra are also adequate
`(Fig. 5).
`Whichever stent the operator uses for a bifurcation, it is
`important to perform a “kissing” balloon inflation at the end
`of the procedure to correct the stent distortion that occurs
`after balloon inflation in the side branch (29). If the
`operator finds it appropriate to stent both branches, we
`recommend the modified T or V techniques.
`Lesions located at the left main stem. Left main stem
`lesions may involve treatment of an aorto-ostial
`lesion
`and/or a lesion located in the body of the left main artery.
`Occasionally, there is a need to treat the distal left main
`stem as a bifurcational lesion.
`The reference size of the left main coronary artery is
`favorable to stent implantation in terms of the restenosis
`rate. The major problem is that in an unprotected left main
`artery, stent restenosis may manifest either as sudden death
`or unstable angina rapidly followed by death. For this
`
`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`2.5
`2.25,2.5
`2.0,2.5
`2.0,2.5
`
`6,10,16,24,28
`8,13,18,23,28
`9,17,27,33
`9,16,26,32
`
`9,12,15,19,25
`8,13,18,23,28,322.25,2.5,2.75
`10,15,18
`9,12,15,18,24,302.5
`2.5
`9,12,15,18,24
`
`2.0,2.5
`
`2.5
`
`No
`No
`No
`No
`
`Yes
`No
`No
`Yes
`No
`
`Low
`Medium
`Low
`Low
`
`Low
`Low
`Low
`Low
`Medium
`
`Diameters(mm)
`
`Lengths(mm)
`
`RadiopacityMarkers
`
`7
`
`11
`
`0
`
`4
`
`2
`
`0
`
`5
`
`5
`
`1.5
`
`Shortening
`
`(%)
`
`4
`
`4
`
`4
`
`3
`
`3–5
`2.5
`
`1
`
`1.6–2.2
`
`2
`
`(%)
`Recoil
`
`10–18
`15
`16
`16
`
`12–17
`15
`
`9
`
`12–17
`20
`
`Metal/Artery
`
`(%)*
`
`0.07
`0.099
`0.09
`0.09
`
`0.075
`0.14
`0.05
`
`0.085–0.095
`
`0.127
`
`Thickness
`Strut(Wire)
`
`(mm)
`
`Stainlesssteel
`Stainlesssteel
`Stainlesssteel
`Stainlesssteel
`
`Slottedtube
`Slottedtube
`Slottedtube
`Slottedtube
`
`*Doesnotnecessarilymeanvesselwallcoverage.
`
`Devon
`GuidantACS
`Jomed
`Jomed
`
`PURAVarioAS
`MultilinkPixel
`JostentPlus
`
`JoStentFlex
`
`cells
`
`Stainlesssteel
`Stainlesssteel
`Stainlesssteel
`Stainlesssteel
`Stainlesssteel
`
`CarbostentSirius,4
`Sorin
`Slottedtube
`BxVelocity
`Cordis,Johnson&JohnsonSlottedtube
`Slottedtube
`BiodivysioSV
`Biocompatibles
`Slottedtube
`beStent(4crowns)MedtronicAVE
`Sinusoidalring
`MedtronicAVE
`AVES660
`
`Material
`
`Structure
`
`Manufacturer
`
`Product
`
`Table1.Continued
`
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`1026
`
`Colombo etal.
`Stent Selection
`
`Table 2. Crossing Profile
`
`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`Product
`
`AVE S670
`AVE S660
`beStent 2
`Biodivysio AS
`Biodivysio SV
`BxVelocity
`BxSonic
`Carbostent
`Multilink Tetra
`Multilink Penta
`Multilink Pixel
`NIR with sox
`Express
`
`Manufacturer
`
`2.5-mm Diameter
`
`3.0-mm Diameter
`
`Crossing Profile*
`
`Medtronic
`Medtronic
`Medtronic
`Biocompatibles
`Biocompatibles
`Cordis, Johnson & Johnson
`Cordis, Johnson & Johnson
`Sorin
`Guidant ACS
`Guidant ACS
`Guidant ACS
`Medinol, Boston Scientific
`Boston Scientific
`
`0.99
`1.07
`
`0.84
`1.07
`1.07
`1.02
`1.04
`1.04
`0.93
`1.09
`1.02
`
`1.09
`
`1.17
`1.07
`
`1.17
`1.14
`1.04
`1.12
`1.07
`
`1.12
`1.09
`
`*Data presented reflect measurements performed by individual manufacturers; the method used to measure and the exact site of
`measurements may differ among different stents.
`
`reason, when stent implantation in an unprotected left main
`artery is clinically indicated, we frequently debulk the lesion
`with directional atherectomy to minimize the risk of reste-
`nosis (30).
`Selection of the stent to be used depends on the issues
`discussed previously concerning ostial lesions and bifurca-
`tional lesions. The only unique aspect of left main stenting
`is the final size of this vessel. It is not unusual, especially if
`intravascular ultrasound (IVUS) is employed (31), to per-
`form a post-stent dilation with a balloon ⬎4 mm. For this
`reason, when the left main artery appears large, we recom-
`mend using slotted-tube stents that can be expanded ⬎4
`mm. The NIR nine-cell, BxVelocity, Tetra and Ultra are
`excellent choices. When the stent is overexpanded and it is
`located in the aorto-ostial position, it is important to realize
`that a significant foreshortening will occur. The operator
`should take this into account when initially placing the stent
`by placing the proximal end of the stent 1 to 2 mm into the
`aorta. In addition,
`if the ostium is left uncovered, the
`operator should not hesitate to place a second stent. The use
`of IVUS may be beneficial
`in determining the precise
`
`position of a stent. The use of stents with no foreshortening
`and with markers like the beStent or Carbostent is an
`important consideration in this context. As a general rule,
`when treating an aorto-ostial lesion, it is important to avoid
`using a stent that is very short, such as an 8- or 9-mm stent.
`This recommendation becomes even more important
`when dealing with a lesion at the ostium of the left main
`artery. We have seen stents ejected from the left main
`stem at
`the time of postdilation due to their short
`anchoring length.
`Calcified lesions. Despite the widespread notion that cal-
`cium affects stent expansion (32), there are only a few
`reports specifically dealing with this issue (33,34). The
`general view is that stent expansion in a calcified lesion will
`yield a smaller final lumen than will expansion in a non-
`calcified lesion. Adequate final expansion is usually achieved
`by stretching the non-calcified arc of the vessel. If an
`adequate final lumen size is achieved, this approach does not
`seem to affect restenosis. To obtain an adequate final lumen
`size,
`it is important to have a slotted-tube stent with
`minimal recoil and good radial strength. The NIR, BxVe-
`
`Figure 1. (A) Baseline angiogram of a lesion (arrow) in the proximal right coronary artery. (B) Angiogram after implantation of a nine-cell, 16-mm-long
`NIR stent. The hinge site at the end of the stent is clear (arrow).
`
`Page 6
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`

`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`Colombo et al.
`Stent Selection
`
`1027
`
`Chronic total occlusions. Stent implantation for chronic
`total occlusions must address two problems: 1) the amount
`of plaque mass in these types of lesions is large; and 2) it is
`not rare that passage through the occluded segment occurs
`by creating a false lumen with reentry.
`These two elements mandate the insertion of a stent with
`good lesion coverage and radial support. The Palmaz-
`Schatz stent was used in the Stenting In Chronic Coronary
`Occlusion (SICCO) study (36), which reported a significant
`benefit of stent implantation (32% restenosis) in comparison
`with percutaneous transluminal coronary angioplasty
`(PTCA) (74% restenosis) after recanalization of chronic
`total occlusions. In TOSCA (15), 410 patients with non-
`acute native coronary occlusions were randomized to PTCA
`or primary stenting with the heparin-coated Palmaz-Schatz
`stent. With 95.6% angiographic follow-up, primary stenting
`resulted in a 44% reduction in failed patency (10.9% vs.
`19.5%, p ⫽ 0.024) and a 45% reduction in clinically driven
`target vessel revascularization at six months (8.4% vs. 15.4%,
`p ⫽ 0.03).
`In addition to various slotted-tube stents (e.g., NIR,
`BxVelocity), the Wallstent needs to be considered for
`dealing with a large vessel, especially for the right coronary
`artery (37).
`The general rule for treating a chronic total occlusion is to
`use a stent with good plaque coverage with a closed-cell
`design, allowing minimal plaque prolapse in this setting
`where there is a large plaque burden.
`
`Figure 2. Four-month follow-up angiogram of the lesion in Figure 1,
`showing restenosis at the hinge site (arrow).
`
`locity, Tetra, and AVE-S family stents are all reasonable
`choices.
`In calcified lesions, the most important part of the
`procedure is adequate preparation of the lesion before stent
`implantation. The amount of calcium visible on X-ray
`underestimates the amount of calcium observed on IVUS.
`Intravascular ultrasound can also distinguish whether the
`calcium is in a superficial or deep location (35). Efforts to
`evaluate the lesion and to prepare the implantation site with
`rotational atherectomy or by cutting the balloon will be well
`rewarded. Post-dilation with a short, non-compliant bal-
`loon is another important step.
`
`Figure 3. Length of balloon protrusion for commonly used stents.
`
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`1028
`
`Colombo etal.
`Stent Selection
`
`JACC Vol. 40, No. 6, 2002
`September 18, 2002:1021–33
`
`Figure 4. Area of the stent cell at nominal (solid bars) and maximal (open bars) expansion for several slotted-tube stents.
`
`Vessels smaller than 3.0 mm in diameter. Stent implan-
`tation in small vessels is associated with a number of
`problems. Initially, no stents were specifically made to be
`expanded in small vessels with the capacity to gain optimal
`radial support at diame