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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3840_Библиотеки_им_академика_М_И_Перельмана
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LATIB ET AL.
location of plaque, angle between branches, diameter of branches, bifurcation site) but also in
the dynamic changes in anatomy during treatment (plaque shift, dissection). Thus the most
important issues in LMCA bifurcation PCI are in selecting the most appropriate strategy for an
individual bifurcationfollowed by the optimalperformance of the procedure. The latteris often
not sufficiently stressed in current PCI, and we advise following the dictum that “the procedure
has only started after the stents have been implanted.” This point will frequently bereiterated
in this chapter. The decision to use one or two stents, or sometimes even three (in case of a
cation), should be made as early as possible. An appropriate and timely taken decision
trifur
will affect the results, save time, lower costs, and lower the risk of complications. Whichever
approach, strategy, or technique is chosen, we think that elective LMCA stenting should always
aim for an optimalfinal result verifiedby IVUS (intravascular ultrasound) unlessthere are good
reasons not to do so.
In thischapter, we haveused case examplesto illustrate which patientsand lesions should
be selected for double stenting and when and how to perform the various double stenting
techniques.
WHO ARE THE PATIENTS WHO QUALIFY FOR ELECTIVE DOUBLE STENTING?
Correct patient selection for double stenting requires accurate assessment of lesion severity,
distribution, extension, and the presence of concomitant disease. This will result not only in
the appropriate patients being selected for double stenting, which is more complex, timeconsuming, and labor intensive than provisional stenting, but also reduce the risk of complications. The major factors that need to be assessed and taken into account, when the operator
is deciding between provisional stenting and elective double stenting, are described below.
Although each of these factors is discussed separately, there is usually a combination of these
factors present that dictates the decision to electively perform double stenting. Figure 1 demonstrates how to use these factors below to select patients for double stenting.
Distribution of Disease
In considering the distribution of disease (Fig. 2) in the LMCA bifurcation, the most important
distinction is whether the disease at the bifurcation only involves one branch of the bifurcation
(LAD or LCX), or if it extends into both branches or into three distal branches when the RI is
present.
when
In general, a double stenting approach from the outset would usually be appropriate
there is disease in both the LAD and LCX.
Small LM
LCX disease +
100
80
60
40
20
Small LM
LCX disease –
Diameter stenosis of LCX (%)
0
123456
However, this only holds true when the LCX
Large LM
LCX disease +
Large LM
LCX disease –
Reference diameter of LMCA (mm)
Provisional
Crush, Culotte
Crush, Culotte, V, Kissing
Figure 1 The diagram demonstrates how to select among the different techniques based on LMCA size and
LCX involvement.
Source
: Photo courtesy of Dr. Seung-Jung Park.
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151
is of a sufficiently large diameter with a large area of distribution and the disease extends more
than a few millimeters beyond the ostium. If the LCX is small or the disease is localized to the
ostium,
esult such as dissection or significant residual stenosis. When the LMCA disease extends to
r
only one
a provisional approach is appropriate with a second stent reserved for a suboptimal
branch, the best strategy is to stent from the LMCA into the diseased branch with
a provisional approach to the nondiseased branch. In this approach, the decision to place a
second stent should be made only after having dilated the unstented branch and after having
performed final kissing inflation (FKI).
The threshold to place a second stent will be lower if the
unstented vessel is the LAD (13).
(A)
(B)
Figure 2 Selecting between elective double stenting and provisional stenting for the LMCA. In this figure, we
demonstrate how we select patients for elective double stenting based on baseline anatomical factors (see text).
(A) There is distal LMCA bifurcation disease involving the LAD but the LCX is undiseased. In this patient, we
stented the LMCA toward the LAD with a provisional approach to the LCX. (B) Distal LMCA disease extending
into both the LAD and LCX, and we would prefer stenting both branches. (C) There is severe distal LMCA disease
involving the LAD ostium but not the large LCX. In this case, we would again favor a provisional approach and
stent toward the LAD. (D) LMCA disease extends into the LAD and LCX. In particular the LCX disease extends
quite a distance from the ostium and we would electively stent both branches.
Continued on page 152
(
)
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LATIB ET AL.
(C)
(D)
Figure 2
(Continued
)
Size of Branch
The diameter of the SB (LCX or RI) and territory of distribution will determine the operator’s
decision whether to electively implant a stent or treat it with a provisional approach. However,
when selecting a strategy for the LMCA, as with other lesion factors discussed here, the size of
the branch (Fig. 2) is not considered in isolation but in combination with the severity andlength
of disease.In general,we would not stentSBs thatare <2.5 mm unless it islong with a somewhat
large territory ofdistribution or the branchis in danger ofocclusion. In contrast, wewould favor
a doublestenting technique from the outset whenthe LCX or RIare atleast ≥2.5 mmin diameter
with a relatively large territory of distribution and has significant disease extending from the
origin to 10to 20 mm or more millimeters distally. For example, in anondominant LCX without
large marginal branches, irrespective of its size, we would not favor elective double stenting.
Similarly, in a large dominant LCX, we would not always stent the LCX if it has only focal
disease localized
to or not extending more than a few millimeters from the ostium.
Angle of Branch
For definition purposes,
the angles between the LMCA–LCX, LCX–LAD, and LMCA–LAD are
designated by the letters A, B, and C, respectively (Fig. 3). Proximal Angle A is defined as the
ELECTIVE DOUBLE STENTING FOR LEFT MAIN CORONARY ARTERY BIFURCATION LESIONS
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153
(A)
(B)
(C) (D) (E)
Figure 3 This is an 82-year-old patient with a recent history of chronic renal dysfunction, acute myocardial
infarction, repeated episodes of pulmonary edema, and episodes of seizures and confusion on the basis of
embolization from a left ventricular apical thrombus. The patient was refused surgical revascularization on the
basis of the patient’s poor general condition, and thus referred for LMCA stenting. (A) The baseline coronary
angiography with severe distal LMCA stenosis and markedly angulated LCX. Angle A is the angle between the
LMCA and the LCX, Angle B is between the LAD and the LCX, and angle C between the LMCA and LAD. Wiring
and predilatation of the LAD and LCX, favorably modified Angle A, which was now less acute (B). We decided
on double stenting due the severity of disease in the LMCA and the dissection of both the LAD and LCX after
predilatation. We elected to perform a minicrush due to the instability of the patient and need to rapidly secure
patency of both branches. A 3.0 × 18 mm Endeavor Resolute zotarolimus-eluting stent (Medtronic Vascular,
Santa Rosa, CA) was implanted on the LAD with minimal protrusion into the distal LMCA (C) and crushed with
an Endeavor Resolute 3.0 × 18 mm implanted from the LMCA to the LCX (D), followed by FKI with two 3.0 ×
12 mm noncompliant balloons (E). The final result was excellent (F) and the entire procedure was performed with
only 50 mls of contrast.
(
Continued on page 154
)
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LATIB ET AL.
(F)
Figure 3
(Continued
)
angle between the LMCA and the LCX, whereas distal Angle B is delineated between the LAD
and the LCX (14–16). The LMCA bifurcation is designated as T-shaped (distal bifurcation angle
◦
B ≥70
) or Y-shaped (distal bifurcation angle B <70◦). The degree of Angle A has an influence
on the accessibility of the SB and can frequently be a reason for initially stenting the SB. When
Angle A is <110 degrees, it may complicate guidewire insertion into the SB. This angle may
also impede recrossing into the SB with a wire, balloon, or stent after MB stenting. However,
the decision to electively implant a stent on the SB should be made only after wire insertion,
may favorably modify this angle. Angle B (between LCX and
which
LAD) is a predictor of SB
occlusion after MB stenting; that is, the more acute the angle, the higher the risk of plaque shift,
omise of the ostium, and SB occlusion (14–16). The wider the Angle A or the narrower
compr
the Angle B, the larger the SB ostium area, which would necessitate the operator to select a
large-cell stent for the MB.
Aswill bediscussed belowin detail,the bifurcationangles willalso influencethe operator’s
decision as towhich double stenting technique will be performedand may also have anegative
effect on long-term outcomes. Angle B may impact the acute and long-term results. Indeed,
very acute angles require the placement of a stent with optimal strut opening potential in the
of stent malapposition in the SB while T-stenting provides complete coverage of the SB ostium
should be avoided withmore acute angles where theculotte or crush techniques area better
but
MB. Conversely, when
the angle is 90 degrees, the crush technique is associatedwith a high risk
choice.
Severity and Length of the Side Branch (LCX) Lesion
As already discussed, the severity and length of disease in the SB (Fig. 2) is probably the most
common reason for performing double stenting of the LMCA. If the SB is large (≥2.5 mm), supplies a relatively large territory of myocardium, and has significant disease that extends 10 to
20
mm ormore fromthe ostium, thenwe prefer performing doublestenting. In assessingthe severity of disease at the ostium of the LCX, the operator needs to be awarethat sometimesthe angulation at the ostium and movement of the LCX may result in what appears angiographically to be
a stenosis but may actually be a “pseudostenosis.” In this regard, IVUS is invaluable in making
an accurate diagnosis as to whether there is large plaque burden resulting in stenosis (Fig. 4).
Presence of Concomitant Distal Disease in the Side Branch (LCX Artery)
The presence of concomitant distal disease affects the LMCA PCI strategy in two ways. First, if
the ostium is nondiseased but there is distal disease close to the ostium that can be covered by
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(A)
(B)
(D)(C)
Figure 4 In this patient, angiography (A) was misleading in that there appeared to be a significant stenosis at
the ostium of the LCX (B: LMCA bifurcation magnified). Isolated LCX ostial stenosis before or after LMCA stenting
is a situation that often leads to confusion and doubts. In this patient, we assessed the LCX with IVUS which
demonstrated in panels (C) and (D) (corresponding to diastolic and systolic frames) that a significant stenosis
was not present (minimum CSA = 5.7 mm
artery with a change in shape of the lumen from circular to eccentric.
2
). This appearance of pseudostenosis was due to movement of the
a long stent from the LMCA, we would prefer double stenting. Second, if, however, the distal
disease cannot be treated with the LMCA stent and requires a second stent to be implanted
distally, we prefer implanting the distal stent first if possible and then treating the LMCA. This
approach avoids difficulty later in passing a stent through stent struts in the LMCA. Obviously,
this only holds true if the patient and LMCA lesion are stable. If not, the LMCA disease should
be treated first.
TECHNIQUES FOR ELECTIVE DOUBLE STENTING OF THE LMCA
This section describeshow toperform and select patients for allthe currentlyutilized techniques
for double stenting as an intention-to-treat. At present, there are insufficient data to determine
which of these techniques is superior in regards to procedural and follow-up events. Although
it is important for an operator performing LMCA intervention to have a good knowledge of
all the techniques described below, the operator would not be amiss to know
only one or two
of these techniques and be able to perform them well. We would stress that it is not only
the specific technique used but rather the meticulous attention to performing the procedure
that is important in ensuring success and improving long-term results (12,17). When dealing
with complex bifurcations involving large territories, where it is crucial to maintain optimal
patency of both branches, we recommend the V-stent or crush techniques. In Figure 5, we have
156
LATIB ET AL.
An approach for LMCA lesions when
using 2 stents as intention to treat
Main branch disease
extending proximal to the
Very short left main
V-stent
Pre
Cross section
Figure 5 Demonstrates how we chose between the various double stenting techniques based on the anatomy
of the LMCA.
Pos
bifurcation and side
branch which has origin
with about 90° angle
T-stent Mini-Crush/Culotte
Pre
Pos
Main branch disease
extending proximal to the
bifurcation and side
branch which has origin
with about 60° angle
Pre
Pos
summarized how we choose among the various double stenting techniques (described below)
based on the LMCA bifurcation anatomy.
The V-Stent and the Simultaneous Kissing Stent (SKS) Techniques
The V-stent and
the SKS techniques are performed by delivering and implanting two stents
together (18,19). One stent is advanced into the SB and the other into the MB. Both stents are
pulled back to create a new carina as close as possible to the original one. When the two stents
protrude into the MB with the creation of a double barrel and a very proximal carina, the
technique is called SKS (19). The main advantage of these techniques is that the operator will
never lose access to any of the two branches. In addition when FKI is performed, there is no
need to recross the side branch stent.
Technique Description—Requires an 8-Fr Guiding Catheter (Fig. 6)
(a) Both branches are wired and fully predilated. It is important to perform adequate predi-
latation to facilitate full stent expansion.
(b) Two stents are positioned into the branches with a slight protrusion of both stents in
the LMCA. Different operators allow a variable amount of protrusion creating sometimes
a rather long (5 mm or more) double barrel in the proximal MB (SKS). Although we
recognize that it is impossible to be so accurate in positioning the stents exactly at the
ostium of each branch, we generally try to limit the length of the new carina
5 mm. Sometimes it is
to facilitate
the advancement of the second stent. This maneuver is essential when the
necessary to advance the first stent more distally into the vessel
to less than
kissing stent technique is used to stent a trifurcation using three kissing stents (need of a
9-Fr guiding catheter). Following accurate stent positioning, it is important to verify their
correct placement in two projections before deploying the stents.
(c) Each stent is deployed individually at high pressure of 12 atm or more. Some operators
prefer deploying the stents simultaneously. When the stents are deployed simultaneously,
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the operator needs to be aware of the risk of LM dissection. This can be avoided by using
lower deployment pressure.
(d) Perform high-pressure sequential singlestent postdilatation followedby medium-pressure
FKI with short and noncompliant balloons. Balloon sizes are chosen according to the
diameter of the treated
vessels. In the event that the reference vessel size proximal to the
bifurcation is relatively small, FKI should be performed using low-pressure inflation to
avoid proximal dissection.
V-stenting
1. Wire both branches
and predilate if
needed.
2. Position two parallel stents
covering both branches and
(A) (B)
V-stenting
(C)
SKS stenting SKS stenting
(A) (B)
extending into the MB
• V: minimal protrusion into MB
• SKS: double barrel into the MB
5. Perform high-pressure
single stent postdilatation and
medium-pressure kissing inflation
with short and noncompliant balloons.
1. Wire both branches
and predilate if
needed.
V-stenting
3. Deploy one stent.
4. Deploy the second stent.
Some operators deploy the two stents simultaneously
3. Deploy one stent.
2. Position two parallel stents
covering both branches and
extending into the MB
• V: minimal protrusion into MB
• SKS: double barrel into the MB
SKS stenting
5. Perform final kissing inflation.
(C)
Figure 6 A schematic representation of the V-technique and simultaneous kissing stents (SKS) technique.
4. Deploy the second stent.
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LATIB ET AL.
Specific Issues
The V-stent technique is probably the easiest and the one that guarantees immediate patency
and access to both branches. We prefer to apply this approach only when the disease does
not extend proximal to the bifurcation (into the distal LMCA) and is the preferred technique
when the LMCA is short or during emergencies. The V-stent technique is also suitable for other
bifurcations, provided the portion of the vessel proximal to the bifurcationis free of diseaseand
there is no need to deploy a stent more proximally.
Proponents of the SKS technique assert that this technique can be performed even if the
LMCA is long and has significant disease distally that extends into the bifurcation. They also
suggest that the SKSis preferredwhen theLMCA isvery large, resultingin asignificant diameter
mismatch with the LAD and LCX, as this technique will ensure apposition and full coverage of
the large LMCA with drug. In our experience, we have found that we have not had difficulty in
performing other two-stent techniques in large LMCA and ensuring good stent apposition with
IVUS guidance and FKI. The SKS technique results in a new metallic carina quite proximally
into the LMCA. We do not know at present what the long-term outcome risks are of leaving
this exposed double stent layer in a vessel when utilizing DES. There have been case reports
describing a thin diaphragmatic membranous structure at the new carina (at the level of the
kissing struts), resulting in an angiographic filling defect (Fig. 7). Other than producing a very
distressing angiographic appearance, the exact long-term significance and relation to adverse
events of this membrane is not known.
Thereare severallimitations forthis techniquethat need tobe considered:(a) thepossibility
of balloon barotrauma to the LMCA body during stent deployment or postdilatation, which
can lead to dissection, progression of disease, or edge restenosis in the ostium and/or shaft of
the LMCA. This can be partially avoided by using short noncompliant balloons for FKI. (b) If
a proximal stent becomes necessary to treat a proximal dissection, there is almost always the
risk of leaving a small gap and the stent needs to be directed toward one of the two arms of
the V. (c) If restenosis occurs in the proximal portion of one or both stents, this would require
crushing one of the stents whichwould make recrossing into the branch covered by the crushed
stent potentially challenging as four layers of stent struts will need to be traversed (Fig. 8).
(d) If disease distal to
guidewires can be challenging, as
the V-stenting or SKS site need to be treated at follow-up, advancing
the stent struts can be easily engaged or crisscrossed making
(A) (B)
Figure 7 The figure demonstrates the angiographic (A) and IVUS (B) appearance of a thin tissue membrane
that developed at the site of kissing struts of the new carina 18 months after SKS of the LMCA.
courtesy of Dr. Young-Hak Kim and Dr. Seung-Jung Park.
Source
: Photo
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159
advancement of balloons and stents impossible. If additional guidewires need to be inserted
during the procedure to treat distal disease (Fig. 9), we recommend using a dual access catheter
such as the Twin-Pass catheter (Vascular Solutions, Minnesota). When previous V-stenting or
SKS needs traversing at another PCI, we suggest passing through the stent with a loop on
the radiopaque part of the guidewire to prevent the guidewire from passing through stent
struts.
(A) (B)
(C) (D)
Figure 8 (A) Baseline angiographyshowing ostial LAD and proximal LCXdisease (LMequivalent); (B) successful
V-stenting with 3 ×20 mm (LAD) and 3 ×32 mm (LCX) Taxus paclitaxel-eluting stents (Boston Scientific, Natick,
MA) with an excellent final angiographic result (C). The patient presented 11 months later with inducible ischemia
on myocardial perfusion scintigraphy and angiography demonstrated focal restenosis at the ostioproximal segment
of the LCX (D). We elected treat this restenosis after V-stenting by converting it into crush stenting of the distal
LMCA. (E) Inflation of a Taxus 3.0 × 16 mm stent into the LAD while another stent (Taxus 3.5 × 16 mm) is
in position from the left main toward the LCX. The LCX stent was then deployed crushing the LAD stent (F).
Procedure was completed with two-step FKI by performing high-pressure SB dilatation (G), followed by FKI with
3.0 × 15 mm (LAD) and 3.5 ×15 mm (LCX) noncompliant balloons (H). The final angiographic result is shown in
panel (I) and follow-up angiography after six months in panel (J).
Continued on page 160
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