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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3585_Библиотеки_им_академика_М_И_Перельмана
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4.3 Lesion Preparation
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Column 21 Selection of the Lacrosse NSE, AngioSculpt, and ScoreFlex° balloons (Fig.4.12a–c)
I prefer the Lacrosse NSE balloon. It appears to me that IVUS shows better cracking of calcied plaques after ination
of the Lacrosse NSE balloon than the AngioSculpt balloon and there may be a good reason for this.
The scoring elements of these two balloons have different structures. The Lacrosse NSE balloon induces cracks
in the longitudinal direction, while the AngioSculpt balloon induces cracks in both the longitudinal direction and
obliquely (in the radial direction at points of inection). Ination of these balloons enlarges the cracks in calcied
plaque, thereby increasing the luminal surface area in the radial direction and leading to dilation of the target vessel.
Radial cracks can hardly contribute to dilation of the vessel in the radial direction, while cracks with both radial and
longitudinal components will contribute to dilation with oblique distortion. Thus, it is clear that the Lacrosse NSE
balloon will be more effective in achieving radial dilation of vessels because the scoring elements of this balloon are
aligned parallel to its longitudinal axis.
In addition, both the AngioSculpt and ScoreFlex balloons have relatively ne metal cutting elements, while the
Lacrosse NSE balloon had high plastic wedges as its cutting elements. These characteristic cutting elements of
the Lacrosse NSE allow it to deform the vessel wall more extensively and crack plaques better during ination. If the
calcied plaque is eccentric, the plastic cutting elements are less likely to injure the relatively soft vessel wall on the
opposite side.
221
Fig. 4.12 Comparison of
scoring/cutting balloons. (a)
Lacrosse NSE ALPHA
scoring balloon. (b)
AngioSculpt scoring balloon.
(c) FlexTome cutting balloon
a
Inflation
b
A cutting balloon with a workin
height of 0.005 inches.
0.005’
c
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4 Stenting ofLeft Main Coronary Artery (LM) Lesions
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4.3.3 Preparing theLAD/LCX Ostia
andtheProximal LAD/LCX
Despite the smaller diameter of the LAD or LCX compared
with the LM, a 3.5-mm stent is usually employed for crossover
stenting from the LM to the LAD or LCX across the ostium of
the other branch. If the LAD or LCX has a smaller diameter
than 3.5mm, the radial strength of the stent will be reduced.
Accordingly, the region from the LAD/LCX ostium to the
Severe calcification
Rotablator
Moderate calcification Mild-trivial calcification
proximal LAD/LCX should be prepared with particular care to
minimize vascular recoil. If there is any calcied plaque, scoring balloon angioplasty should be performed for pre-dilatation.
4.3.4 Practical Approach toPreparation
Figure 4.13 shows the algorithm used at my center when preparing LM bifurcation lesions for stenting.
pre-treatment
scoring balloon
HPB (high pressure balloon)
inadequate
debulking
scoring
balloon
Fig. 4.13 Preparation of LM bifurcation lesions for stenting at my center
adequate
debulking
HPB
• High-pressure inflation of a slightly
undersized scoring balloon
• KBI with Lacrosse NSE balloons inflated
at about 8 atm
Stent implantation after reassessment by IVUS
4.3 Lesion Preparation
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223
Before preparing an LM bifurcation lesion, I perform
IVUS to estimate the vessel size, the extent of calcication,
and the properties of the plaques. The approach to preparation of such lesions is stratied according to the extent of
calcication.
Fig. 4.14 LM bifurcation
lesion with eccentric
calcication. IVUS showed
eccentric calcication in both
the LAD and the LCX
LM LAD os LAD
4.3.4.1 Preparing aBifurcation Lesion
withEccentric Calcication
Figure 4.14 shows an LM bifurcation lesion with markedly
eccentric calcication on IVUS. Alternating high-pressure
ination was performed rst, followed by simultaneous
ination (8atm) of two 3.25-mm Lacrosse NSE balloons in
the LM-LCX and LM-LAD, achieving dilation of the calcied region at the bifurcation (Fig.4.15).
LCX os
LCX
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4 Stenting ofLeft Main Coronary Artery (LM) Lesions
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Fig. 4.15 Preparation of the
lesion shown in Fig.
LAD and LCX were
pre-dilated by alternating
high-pressure ination,
followed by KBI with slightly
undersized Lacrosse NSE
balloons
4.14. The
LCX
: Lacrosse NSE 3.25×13 mm
18 atm
LMT bifurcation
LAD
: Lacrosse NSE 3.25×13 mm
16 atm
LCX
KBI
: Lacrosse NSE 3.25×13 mm
8 atm
LAD
4.3.4.2 Preparing aSeverely Calcied Bifurcation
Lesion
Figures 4.16 and 4.17 show an LM bifurcation lesion in a
dialysis patient with severe calcication in the LM-LAD and
also in the LCX that prevented delivery of the IVUS catheter
into the LAD.
Rotablation was performed with a 1.75-mm burr and then
a 2.25-mm burr in the LAD, while a 2.25-mm burr was used
in the LCX.Then both the LAD and LCX were dilated with a
4.0mm cutting balloon. Subsequently, simultaneous ination
of 4.0mm and 3.75mm balloons in the LAD and LCX, respectively, achieved adequate preparation of the lesion for stenting.
LAD os
LM LCX
Fig. 4.16 LM bifurcation lesion in a dialysis patient. IVUS showed
severe calcication in both the LAD and LCX
4.3 Lesion Preparation
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225
Fig. 4.17 Preparation of the
lesion presented in Fig.
4.16.
Rotablation with a 2.25-mm
burr was followed by ination
of a 4.0-mm cutting balloon.
Subsequently, simultaneous
ination of 4.0mm (LAD)
and 3.75mm (LCX) balloons
induced cracks in the calcied
lesion, resulting in adequate
preparation for optimal stent
deployment
LAD
: Rota 1.75mm
LAD
: Rota 2.25mm
LAD, LCX
: Cutting balloon 4.0 mm
LCX
: Rota 2.25mm
KBI
: LAD 4.0mm, LCX 3.75mm
LM bifurcation
LAD os
LCX os
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4 Stenting ofLeft Main Coronary Artery (LM) Lesions
4.4 Stenting Strategy andProcedure
Stent implantation should only be done after adequate lesion
preparation. Stenting should generally be provisional and
should be performed on the basis of the following concepts
and according to the following procedures.
4.4.1 Stenting aRelatively Long LM
withPlaque Conned totheOstium or
Part oftheTrunk (See Fig.4.2a andc)
You should implant a two-link DES so that its distal edge
is within the LMT. If the LM has a diameter > 3.5 mm
and there are no calcied plaques so the vessel will only
show modest recoil, pre-dilatation should be completed by
inating a balloon with a diameter of about 3.5mm. If the
lesion is pre-dilated to a diameter greater than 3.5mm, a
stent implanted by using a 3.5-mm SDB will show malapposition and will be likely to migrate immediately after
implantation.
After a stent has been implanted, it may migrate or be
deformed during withdrawal of the SDB or advancement of
a post-dilatation balloon. To avoid this, the stent should be
deployed to a diameter of 3.5 mm in order to create mild
vascular recoil, since this will ensure that the stent becomes
xed and does not migrate from the landing zone.
If a 4mm DES with 0 to 2 links is approved for use in the
future, it should be used for the above procedures instead of
a 3.5-mm DES.
Stenting with KBI can only achieve favorable outcomes if
the following requirements are met: (1) use of an optimally
designed stent; (2) optimal guidewire routes; and (3) avoidance of stent deformation during balloon delivery.
If KBI is performed after implanting a two-link stent
(e.g., a Cypher stent), it can actually lead to a worse outcome
in many cases due to the stent design. Post-stenting KBI may
also enhance jailing of the SB by a three-link stent. In contrast, post-stenting KBI is less likely to induce SB jailing and
vascular stress if a two-link stent is used.
Stenting with KBI, especially at the LM bifurcation,
should only be performed if the following requirements are
met. First and most importantly, an optimally designed stent
is needed. Second, the SB guidewire should cross the stent
through the most distal cell at the carina and come into contact with the carina. After post-stenting KBI, you must check
whether the SB guidewire has followed an appropriate route.
Third, POT prior to SB wiring has recently become the standard intervention for preventing stent deformation. Fourth,
if the SB balloon becomes blocked by a stent strut, it should
not be advanced forcibly and must be delivered by a nonpushing technique (see Chap. 2). The anchor technique, in
which an anchoring balloon is used to provide support for
advancing the balloon, must not be employed.
I think that stenting with KBI is useful if it is performed
appropriately when these requirements are met. It is doubtful whether previous studies that have found negative results
for post-stenting KBI actually compared outcomes after KBI
was performed with these requirements versus outcomes
after stenting alone.
4.4.2 Stenting theLM Bifurcation
In general, provisional stenting should be performed at the
LM bifurcation, but a planned two-stent technique may be
employed.
4.4.2.1 Stenting withKBI
Need forPost-stenting KBI
I think that stenting with KBI is the basic method of LM
bifurcation stenting. This strategy is adopted for the following reasons: (1) to achieve optimal stent apposition, (2) to
achieve sufcient dilation of the vessels around the carina
to their normal diameters, and (3) to ensure good accessibility of the LCX if PCI needs to be performed in the future.
Crossover stenting may sometimes be performed across the
LCX ostium without post-stenting KBI, but is limited to
cases where the LCX has a very small diameter and perfuses
a very small territory of the left ventricle.
Practical Stenting with KBI
Crossover stenting is performed from the proximal MB to
the distal MB or to the SB across the ostium of the other
branch. In comparison with the proximal MB, the distal MB
and the SB often have much smaller diameters. If the MB
(LM) has a large diameter, a Nobori 3.5-mm JV stent needs
to be implanted, even if the landing zone will be located
in the distal MB (LAD) with a smaller diameter (about
3.0 mm). Because a Nobori 3.5-mm JV stent is usually
deployed by inating the SDB at 4.0atm, the stent should
be implanted by initial ination at 4 to 5atm. Subsequently,
the SDB should be pulled back until its distal marker is at
the carina and then inated at a higher pressure of up to
about 14atm (Fig.4.18).
The SDB should be withdrawn slowly so as to prevent the
guiding catheter from becoming deeply engaged at the LM
ostium and its tip from deforming a stent strut (Fig.4.19). If
the guiding catheter appears to spontaneously enter the LM
ostium, you may need to pull it back slightly in order to prevent catheter advancement while withdrawing the SDB.
4.4 Stenting Strategy andProcedure
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227
Note that pulling the guiding catheter back too far when
attempting to prevent its advancement may result in loss of
coaxiality with the LM (or the stent) after withdrawal of the
SDB, which may prevent delivery of a post-dilatation (POT)
balloon. If an attempt to regain coaxiality of the guiding
catheter with the LM is made at this time, the tip of the guiding catheter often causes deformation of the proximal edge
of the unapposed stent. Thus, it is important not to pull the
catheter back excessively, and if the guiding catheter loses
coaxiality with the LM, you should try to regain a coaxial
position carefully without deforming the proximal edge of
the stent.
In some cases, you can deliver a medium-sized balloon
for pre-dilatation rst and then move the guiding catheter to
and fro or rotate it along the balloon catheter to regain coaxiality with the LM while avoiding stent deformation.
After withdrawing the SDB, you should immediately perform POT using a balloon that matches the diameter of the
LM ostium. A new balloon should generally be used, but if
the pre-dilatation balloon is reused, it should be reformed
before introduction into the guiding catheter or rewrapped
in the guiding catheter by ination at about 10atm before
delivery into the stent. The POT balloon should be inated at
14atm inside the stent. In the presence of a jailed guidewire,
the POT balloon should not be inated at a pressure exceeding 14atm to avoid trapping the guidewire. If symptoms and
the hemodynamic prole permit, the POT balloon should be
inated at a rate of about 1atm per second to prevent it from
slipping out of the stent.
POT is often difcult to perform if the LM is less than
8mm in length. In particular, when the LM ostium is tapered,
the POT balloon and the stent are very likely to slip out of the
ostium. As stent slippage toward the sinus of Valsalva may
lead to excessive expansion of some of the stent struts, there
is no use performing POT (Fig.4.20).
If the LM is short (especially if it is tapered), it is better not
to try POT and just perform KBI with great care. Since KBI
can correct tapering of the LM to some extent, high- pressure
POT can reliably dilate the LM after KBI (Fig.4.21). In any
case, bifurcation stenting should be accomplished by nal KBI.
Subsequently, SB rewiring should be performed via the
Crusade catheter according to the procedure described in
Chap. 2 (see pages 155 to 157). Since the LM branches (LAD
and LCX) do not lie in a single plane, it may be difcult to
use CAG to determine whether the SB guidewire has crossed
the stent through the most distal cell at the carina. In general,
the LM bifurcation can be seen most clearly in a steep spider
view, but this view does not always provide en face observation of the bifurcation. Since it is very hard to conrm the
correctness of the guidewire route without an en face view of
the bifurcation, you should perform provisional KBI.
Nonetheless, it is necessary to minimize SB jailing at
the LM bifurcation. If severe SB jailing persists and culotte
stenting has to be performed subsequently, you may have difculty delivering a stent into the SB across the MB stent or
may cause deformation of the MB stent. Since these events
must particularly be avoided in LM bifurcation stenting, you
should perform IVUS immediately after KBI to assess the
extent of SB jailing. If necessary, you should attempt SB
rewiring through the most distal cell of the MB stent at the
carina and then repeat KBI (see Chap. 2 [pages 168 to 171]).
Before performing KBI, you need to withdraw the guidewire that has been jailed by the SB guidewire. For tips about
withdrawing a jailed guidewire, please also refer to Chap.
2 (page 183). While withdrawing the jailed guidewire, you
should take great care to prevent stent deformation.
abc
Fig. 4.18 Bifurcation stenting with a large-diameter proximal MB
(LM) and small-diameter distal MB/SB. (a) Baseline CAG. (b) A
Nobori 3.5-mm JV stent was implanted from the LM to the proximal
LAD (Segment 6) with low-pressure (5atm) expansion. (c) The SDB
was pulled back to the LM trunk and inated at a high pressure (16atm)
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Fig. 4.19 Deformation of a stent implanted at the LM ostium. During
withdrawal of the SDB, the guiding catheter may be advanced into the
LM ostium, deforming the stent
4 Stenting ofLeft Main Coronary Artery (LM) Lesions
Fig. 4.20 Precautions when performing POT. As a result of the POT
balloon slipping out of the ostium, the stent implanted in the LM has
been deformed with overexpansion of its struts
a
b
c
Fig. 4.21 Technique for performing POT and KBI in a short (tapered) LM.It is sometimes better to perform KBI rst (a & b) and then POT (c).
In any case, bifurcation stenting should be accomplished by nal KBI (d)
d
ab
4.4 Stenting Strategy andProcedure
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229
4.4.3 Stenting uptotheOstium
If IVUS shows some plaque in the LMT, stenting should be
performed up to the ostium to avoid positioning the stent
edges in the trunk. If the LM is not too long for a stent
≤28 mm in length to easily cover the entire LM from its
ostium to the LAD ostium, the LM should be stented up to
the ostium even if the plaque burden is trivial.
To locate the proximal edge of a stent just at the ostium,
it is generally recommended to position it at the end of the
shoulders of the LM ostium in the AP cranial view (Fig.4.22).
However, it is sometimes impossible to distinguish the
shoulders from the trunk on CAG, even after ne adjustment
of the uoroscopy angle. In such cases, you should introduce
an IVUS catheter along the guidewire inserted into the LCX
and use IVUS to locate the proximal edge of the stent and
the LM ostium. Subsequently, you can adjust the position of
the stent so that its proximal edge overlaps the LM ostium by
advancing and withdrawing it repeatedly. When the proximal edge of the stent has been positioned to overlap the LM
ostium, you should perform non-contrast CAG.While conrming that the stent remains in position, you should slowly
withdraw the IVUS catheter, leaving only guidewires in the
LM, and should then implant the stent. To prevent migration
of the stent together with the IVUS probe, the LM should be
pre-dilated to enlarge it enough to easily accommodate these
devices.
This contrast-free method for accurately positioning a
stent is very helpful for LM stenting in patients with chronic
kidney disease.
Fig. 4.22 Conrming the position of the stent edge. (a) AP and cranial
30° projection. (b) LAO 50° and caudal 29° projection. The AP cranial
projection allows visualization of the LM ostium (red arrow). The stent
should be implanted so that its proximal edge protrudes from the
ostium. While the LAO caudal projection displays the LM bifurcation,
it is not suitable for identifying the LM ostium
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4.4.4 Stent Edge intheLMT
4 Stenting ofLeft Main Coronary Artery (LM) Lesions
If the LM is too long to achieve complete coverage from
its ostium to the LAD ostium with a 28-mm stent, you will
need to choose between fully covering the LM or placing the
stent edge in the LMT. If there is a signicant plaque burden, chronic progression of stenosis at the proximal edge of a
stent frequently occurs after stenting of other coronary arteries and similar outcomes are expected in the LM.Despite the
lack of denite evidence, I think it is acceptable to implant
the stent with its edge in the LMT if the LM is relatively
long and has a relative plaque area of about ≤30%. If the LM
is ≤10 mm long, it should be stented completely from its
ostium to the LAD ostium.
4.4.5 Culotte Stenting
4.4.5.1 Indications forCulotte Stenting
If provisional MB stenting with KBI leads to compromise of
the SB, a second stent has to be implanted in the SB.There
are two options for such two stenting, which are T stenting
and culotte stenting. At the LM bifurcation, I often prefer
culotte stenting for the following three reasons:
1. With T stenting, the proximal edge of the SB stent inevitably protrudes into the MB lumen and shows malapposition to the MB/SB wall.
2. With T stenting, the stent struts at the shoulders of the
bifurcation receive no support from the contralateral wall
and lose radial strength. In contrast, culotte stenting creates a double layer of struts at the bifurcation shoulders
supported by the lateral wall of the proximal MB, thus
leading to a twofold increase of radial strength (Fig.4.23).
3. Culotte stenting is less complicated than T stenting. The
only additional procedures required are SB rewiring and
repeated POT plus KBI.
a
b
c
Fig. 4.23 T stenting versus culotte stenting. (a) Provisional T stenting.
(b) Modied T stenting. (c) Culotte stenting. With provisional or modied T stenting, the stent struts may lose radial strength on the contralateral side
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