Stenting of bifurcation lesions

Stenting of Bifurcation Lesions
Presenter Dr Virbhan Balai
Moderator – Dr Vinod Sharma

Introduction
Coronary bifurcation lesions account for 15–
20% of all coronary lesions that require PCI.
Bifurcation stenosis is one of the most
complex coronary lesions requiring
endovascular treatment.
The best approach for the management optimal
procedural outcomes and long-term success
rates is still debated.

Coronary Artery Bifurcation Lesion
Intervention: A Challenge
Coronary artery bifurcation lesions pose a major
challenge for interventional cardiologists.
PCI for the treatment of coronary artery
bifurcation lesions is associated with increased
risk of complications.
Higher risk for sub acute and late stent thrombosis
is of major concern.
Currently, there is no guideline to address the
interventional technique in bifurcation lesion.

Coronary Artery Bifurcation
Classifications
There are six major bifurcation lesion
classifications described.
Four classifications were published in the era
of BMS.
Similar in describing a given bifurcation
lesion.

1. Sanborn's classification
2. Duke classification
3. Safian classification
4. Lefevre classification
5. Medina classification
6. Movahed's classification

Summary of currently published major
coronary bifurcation classifications.

Lefevre classification of bifurcation lesions.

Medina classification
• They divided bifurcation lesions into three segments:
1. Proximal segment of the main branch
2. Side branch ostia
3. Distal segment of the main branch.
• Any involvement of each segment will receive the
suffix 1, otherwise suffix 0 was assigned starting from
left to right.
• Example, lesion 1,0,1 means that proximal segment,
and side branch ostia are diseased but the distal part of
the main branch is free of disease.
• Easier to remember, endorsed by European Bifurcation
Club.

Medina bifurcation classification.

Limitations
• Medina classification failed to include two
important features of bifurcation lesions:
1. Angulation of branches (prognostic feature).
2. The size of the proximal healthy segment
3. Redundancy in describing two different
lesions with similar technical decision
making.

Movahed classification
• Based on a system that is composed of a single
prefix to which up to four different suffixes are
added.
• Prefix B (for Bifurcation lesion) to which four
different suffixes can be added.
• Using suffixes that directly describe the
anatomically important features of bifurcation
lesions makes this classification very easy to
remember.

Stenting of bifurcation lesions

• A large proximal segment is a requirement for the KST,
an important feature of this classification.
• The first suffix of this classification addresses this
feature.
• If the proximal segment is large enough, it is assigned
the first suffix of L (for Large proximal segment).
• If the proximal segment is small (less than two-thirds of
the sum of the diameters of both branch vessels) it is
assigned the first suffix of S (for Small proximal
segment).
• BL lesions are suitable for the KST, whereas BS lesions
are not.

• The second suffix describes involvement of
branches.
• If the ostia of both bifurcation branches are
involved in the significant atherosclerotic
disease process, the suffix number 2 is used.

• If only the main branch is diseased regardless
of whether it is in the proximal or distal
segment, suffix 1m is used.
• For involvement of the side branch only (or
anatomically less important branch), suffix 1s
is used.

• The third important suffix in this classification
describes the angulation of bifurcation branches, which
has been ignored in other classifications.
• Steep angulation makes access to the side branch
difficult after main branch stenting and is significantly
associated with adverse outcome.
• Dzavik et al. found that there was a significant increase
in the long-term mortality in patients with highly
angulated lesions who were treated with the CRT.
• A steep angle is significantly associated with the risk of
abrupt vessel closure or side branch occlusion.

• The suffix V is given for shallow angles less than
70° (which looks like a V)
• Suffix T is given for a bifurcation with a steep
angle of more than 70 degree (which looks look
like a T).
• Example, a BS2T lesion is a bifurcation lesion (
– B for bifurcation lesion
– S for small proximal-not suitable for KST
– 2 for involvement of both ostia
– T for steep angulation of the branches.

An example of a BL2V lesion. A bifurcation lesion with a large proximal segment
and involvement of both ostia (2) with an angle of less than 70° (V) between the
branches that was successfully treated using the kissing stent technique.

• Optional suffixes for other high-risk features
• LM was used for left main
• CA for calcium
• 'TO' (for total occlusion)
• 'TR' (for thrombus-containing lesion).

• BS2T-LM-CA-TR lesion.
• Heavily calcified thrombus containing lesion
involving LM with small healthy proximal
segment, involvement of both left anterior
descending arterty and circumflex ostia, and
steep angulation as.

Interventional Techniques in the
Treatment of Bifurcation Lesions
• The European Bifurcation Club has divided
bifurcation interventions into categories
depending on the location and timing of the first
stent implantation.
• If the first stent is planted in the main branch, it is
called 'M' (for Main branch),
• If it crosses the bifurcation, it is called 'A' (for
Across)
• If the stent is placed in the side branch first, it is
called S (S for Side branch).

• The most common bifurcation techniques with
regards to stenting have been recently classified
into six categories:
1. The one-stent technique (OST)
2. The stent with balloon technique (SBT)
3. The KST
4. The T stent technique (TST)
5. The CRT
6. The cullotte stent technique (CUT)

When to Choose One- or Two-stent
Techniques?
• The simplest technique is one-stent technique (the OST or the SBT).
• The long-term outcome of the OST has been at least as good as or
even better than two-stent techniques regardless of stent type.
• The only two-stent technique that has shown better long-term
outcome in comparison to the OST is KST (with regards to stent
restenosis).
• Earlier trials comparing two-stent techniques have shown an
increase in adverse outcomes in comparison to the OST in the BMS
era.
• Restenosis rate (57 vs 21%) and target lesion revascularization were
higher for stenting both vessels (43 vs 8%).

• Using two-stent techniques in the era of DES did
not improve re stenosis rate.
• Apart from the KST in two large trials, other two-
stent techniques have not been superior to OSTs.
• Restenosis usually depends on the disease burden
of the side branch.
• In the Nordic study, the presence of over 50%
lesions in the side branch was associated with a re
stenosis rate of 11-19%, whereas less than 50%
side branch disease was associated with an in-
stent re stenosis rate of 4.6-5%.

• The risk of sub acute stent thrombosis has been
higher using two-stent techniques in the majority
of trials.
• Provisional side branch stenting in B2 lesions
(both ostia are diseased) poses a high risk for side
branch occlusion and increases procedural
complication rate.
• The risk of side branch occlusion in B2 lesions
can be as high as 65% depending on the side
branch angle.

• Two-stent techniques offer safer access to both diseased
branches in the high-risk lesions.
• For easier advancement of two stents in the bifurcation
lesions, balloon pre dilation is recommended before
stenting.
• Any bifurcation intervention poses a high risk for acute
side branch occlusion.
• This may require larger guide catheter size and stronger
guide support.
• Therefore, in high-risk bifurcation lesion interventions,
it is recommended to use a 7-Fr sheath size.

Technical Features
• One-stent Technique
• The OST is based on a simple technique using
one stent.
• This is the best technique in bifurcation lesions
with a small side branch that can be ignored.
• After the initial stent deployment in the main
vessel, the side branch will be left alone if no
significant stenosis or plaque shift occurs at
the side branch ostium.

Kissing Stent Technique
• The KST requires simultaneous advancement of two
stents that are positioned side by side into each
bifurcation branch with the creation of a new carina.
• Also known as V stenting.
• The major advantage of this technique is the ability to
maintain access to both branches at all times.
• The occurrence of an edge dissection or the presence of
additional stent struts in the main vessel poses a
theoretical risk of stent thrombosis.
• The subacute stent thrombosis rate for this technique
has been low in the DES era.

• The most important anatomical requirement of this
technique is the presence of a large proximal segment in
order to accommodate the proximal ends of the two stents.
• Therefore, BL lesions with the proximal healthy segment of
at least two-thirds of the sum of the diameters of both
bifurcation branches are best suitable for this technique.
• Steep angulations may cause difficulty in advancing two
stents simultaneously, making BT lesions more risky with
this approach.
• It is important to perform final kissing inflation of both
stents at a low pressure for optimal stent deployment.

• The sequence of this technique is as follows:
1. First, both stents will be deployed at a low
pressure (6-8 atmospheres).
2. Next, both stent balloons are deflated and
each balloon is inflated sequentially to a high
pressure (14-16 atmospheres) followed by
final inflation of both stent balloons at a low
pressure again at the end of the procedure.

Drawback
• Proximal edge dissection- could be difficult to
treat.
• A long proximal disease segment may require
initial simple stenting of the proximal segment
in order to avoid creating a long carina.
• Requiring a large at least 7 Fr sheath size in
order to advance two stents simultaneously.

T Stent Technique
• The TST requires positioning of two stents in a 'T' fashion.
• This technique has many other names such as 'modified T technique'
or 'classic T technique and there are many different variations.
• Pullback technique is a easiest and safest approach, here a stent is
placed in the side branch and a balloon in the main branch, which is
inflated to a low pressure.
• The side branch stent is then pulled back to the side branch ostium
while a balloon is inflated at low pressure in the main branch,
protecting the main branch from excessive side branch stent mal
position into the main branch.
• After the stent deployment in the side branch, stenting of the main
branch is then performed if the main branch is compromised or has a
significant lesion.

• A different approach is also described as mini crush.
• In this approach, after initial balloon predilatation, two
stents are positioned simultaneously in both branches.
• Next, the side branch stent is inflated with minimal
stent overhang in the main branch.
• After the removal of the side branch stent balloon, the
main branch stent is deployed.
• This will clear and push the minimal side branch stent
overhang back to the side of the vessel wall.
• Final kissing balloon inflation will conclude the
procedure.

• It is also possible to stent the main branch first and then
stent the side branch through the stent struts with the risk
that advancement of the side branch stent could be difficult.
• This is the best suitable bail-out technique when after the
initial main vessel stenting and side branch balloon
angioplasty, the side branch result remains suboptimal or
major dissection of the side branch requires additional
stenting.
• The loss of direct side branch access after the main branch
stenting is a major drawback of this approach.
• This technique can be best utilized in bifurcation lesions
with small proximal segments that are not suitable for the
KST such as BS2 lesions.

Crush Stent Technique
• The CRT, pioneered by Colombo et al.
• Lost enthusiasm due to a high rate of sub acute
thrombosis and difficulty to rewire the side
branch for final kissing.
• Consists of advancing two stents simultaneously
into both bifurcation branches.
• The proximal segment of the side branch stent is
first deployed in the main branch and is then
crushed to the main branch vessel wall ( after
stenting of the main branch).

• Modification of this technique is called reverse crushing, which is done in the
reverse fashion.
• If after the one-stent technique the side branch ostium has significant lesion despite
balloon angioplasty, reverse crush technique can be used as a bail-out technique.
• In this situation, a second stent is advanced into the side branch though the main
stent struts.
• Then, a balloon in the main branch is positioned at the level of bifurcation.
• Next, the proximal part of the side branch stent is retracted into the main branch
and deployed.
• After the removal of the side branch balloon, main branch balloon inflation will
crush the proximal side branch stent strut.
• Then, the final kissing balloon is performed.
• At the end of the procedure, the side branch will be rewired and final simultaneous
kissing balloon inflation is performed.
• The main advantage of this technique is that it is compatible with a 6 Fr size
system.

Drawbacks
1. Difficult to rewire the side branch in steep
angulations such as T lesions.
2. Sub acute stent thrombosis and side branch
restenosis rates high.
3. Technically challenging, since rewiring of
three stent layers could be difficult.
This technique has fallen out of favor.

• The CRT has a major limitation related to the
difficulty in rewiring and advancing an
angioplasty balloon across three layers of stents.
• In order to overcome this limitation, a modified
version of the CRT, known as the sleeve
technique, is successfully utilized clinically.
• This technique utilizes an angioplasty balloon
first (as opposed to a stent) in the main branch
after stenting of the side branch in order to crush
the proximal part of the side branch stent.

• Using only a balloon in the main branch for crushing has the distinct
advantage of having only two layers of stent in the side branch
ostium for rewiring.
• Before final stenting of the main branch, the side branch ostium is
rewired and ballooned together with main branch balloon inflation
(first kissing balloon) creating an open side branch ostium.
• The side branch is now like a new sleeve giving the name of the
sleeve technique.
• After main branch stenting, rewiring of the side branch ostium is
much easier since only one stent layer needs to be recrossed for the
final kissing balloon inflation.
• Using this technique, successful final kissing balloon inflation could
be performed in all patients in a small trial.

• However, subacute stent thrombosis rate remains high at
2.4%.
• Furthermore, this modification adds substantial time, cost
and complexity to the CRT procedure and there are no long-
term follow-up data available at this time.
• A modified TST, which is described in the previous section,
is called mini crush, which is now utilized by many
interventionalists in order to avoid positioning many layers
of stents in the main vessel.
• The CRT, similar to the KST has the disadvantage of
requiring a large at least 7 Fr sheath size in order to advance
two stents simultaneously, unless reverse crush or sleeve
technique is utilized.

Cullotte Stent Technique
• The CUT, also described as Y stenting or 'trouser legs‘.
• Was associated with high restenosis rates in the past.
• It is gaining popularity in the era of DES.
• This technique is suitable for
1. T or V lesions when both ostia of the bifurcation branches
are diseased.
2. The lesions when the size of the side and main branches
are similar.
3. In case of an unsatisfactory side branch result after main
branch stenting using BST, the CUT.

• With this technique, the operator should first stent
the less angulated or most diseased branch vessel,
and then rewire the other branch through the stent
struts.
• Next, the second stent is positioned across the
second branch with positioning of the proximal
stent segment in the proximal part of the
previously stented segment in the other branch.
• Final simultaneous kissing balloon inflation
should be performed in order to expand stent
struts.

Approach to the Treatment of
Bifurcation Lesions
• Visualize the bifurcation branches in order to assess if a lesion is a
true bifurcation.
• If there is a small space between the main and the side branch, the
lesion will be categorized as BC lesion (close to bifurcation).
• These lesions are not true bifurcation lesions and should be treated
with careful positioning of one stent in the main branch before the
bifurcation site.
• True bifurcation lesion → ? importance of the side branch vessel
size.
• If the side branch vessel is small ( ≤ 2-2.25 mm) or supplies small
territory, the lesion should be classified as BN (non significant
bifurcation).
• In this case, the side branch should be ignored and stenting of the
main vessel should be performed using the OST.

An algorithmic approach for the
treatment of bifurcation lesion.

• If the side branch is found to be important, the
operator needs to evaluate atherosclerotic disease
involvement of the main and side branches.
• If only one ostium is involved, it is important to
know which branch is diseased.
• If the main branch is not involved, the operator
should reconsider intervening on the side branch
with a potential risk of injuring and compromising
the main branch.

If the intervention can not be differed due to large
side branch size-
A OST with pullback protection of the main branch
should be used by positioning an inflated balloon at
low pressure in the main branch before ostial side
branch stenting.
If only the main branch ostium is involved in the
disease process-
The OST is the easiest preferred technique with
provisional side branch angioplasty or stenting if the
side branch is compromised after main branch
stenting.

If the branch angle is over 70°, advancement
of two stents into the side branch could be
difficult.
The CRT is technically more challenging in
angulated lesions and is associated with
increased adverse outcome in these lesions.
Should avoid the CRT in angular BT lesions.

If the branch angulation is less than 70°, the
TST runs the risk of missing the side branch
ostium.
Therefore, the CUT or the CRT should be
considered initially.
If the TST is used, the pullback technique, also
known as the mini crush technique, would be a
better choice in order to avoid missing the side
branch ostium.

Summary of Advantages and Disadvantages of
Different Bifurcation Interventional Techniques

Other Technical Aspects of Bifurcation
Intervention
• Wiring Technique
It is very useful to maintain side branch access
during PCI of bifurcation lesions.
In the KST, wire access to both branches is
maintained at all times.
Therefore, this technique poses the lowest risk of
side branch occlusion.
All other techniques require removing the side
branch wire at some point during the course of
intervention.

Some interventionalists advocate keeping and jailing
the side branch wire throughout the procedure after
main branch stenting in order to have a road map to the
side branch for rewiring.
This could be extremely helpful in the case of side
branch occlusion after main branch stenting.
There are no data in the literature to systematically
evaluate and compare the jailed wire technique versus
removing the side branch wire before the main branch
stenting.
There is currently no consensus about these two wiring
approaches.

Final Kissing Ballooning
In order to optimize stent geometry in the main and side
branches, a final kissing ballooning is recommended in
procedures that require additional side branch
intervention.
This recommendation is based on many trials indicating
improvement in the long-term outcome using this
technque.
The superiority of final kissing balloon angioplasty has
been clearly demonstrated in many trials using the CRT.
However, there is no randomized trial or consensus
statements to evaluate balloon sizing or balloon overlap
for the kissing balloon angioplasty.

It is recommended to avoid significant stretching and
upsizing of two balloons during final kissing inflation
in order to prevent trauma or perforation to the vessel
walls.
Selection of balloon diameter should be made based on
the distal diameter of each branch.
Short balloons should be used in order to avoid
inflation outside the stent preventing edge dissection.
In the side branch, the use of short balloons could
reduce distal vessel injury.
Inflation pressure should be guided by the technique.

 Sequential high-pressure balloon inflation before final kissing
balloon angioplasty may be necessary for optimal stent expansion.
 For example, after initial deployment of two stents using KST, each
stent balloon should be inflated to high pressure sequentially before
final simultaneous low-pressure kissing balloon angioplasty.
 As mentioned earlier, coronary bifurcation intervention is associated
with increased procedural risk.
 The majority of acute complications are related to the side branch
occlusion.
 The use of glycoprotein IIb/IIIa inhibitors has been shown to
decrease the risk of side branch closure in the Evaluation of Platelet
IIb/IIIa Inhibitor for Stenting (EPISTENT) trial using abciximab.
 Therefore, the use of glycoprotein IIbIIIa inhibitors is encouraged
during coronary bifurcation interventions

Special Stents Designed for
Bifurcational Intervention
Many new bifurcation specific stents have been
developed for safer use in coronary bifurcation
lesions.
None of these stents are approved in the USA.
Some of these stents are combined with delivery
systems that allow permanent access to the side
branch.
This approach can potentially decrease procedural
time and reduce the risk of the side branch
occlusion.

Summary & Conclusions
Coronary artery bifurcation lesion intervention
is challenging with higher risk for stent
thrombosis, stent restenosis and procedural
complications.
With the availability of DES, coronary artery
bifurcation interventions are increasing in
numbers.
In general, one stent should be used if
possible.

Bifurcation lesions involving both ostia (B2 lesions) are
at high risk for side branch closure.
Other complex techniques such as two-stent techniques
may be the preferred approach in this setting in order to
reduce the rate of acute complications.
No consensus statement about using specific techniques
for a given bifurcation lesions requiring two stents.
The choice of two-stent technique remains at the
discretion of interventional cardiologist depending on
expertise and lesion anatomy.

Stenting of bifurcation lesions

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