Approach to coronary bifurcation lesions

WHAT IS BIFURCATION LESION?
APPROACH TO BIFURCATION LEISONS

A ( approach) – between proximal MB & SB.
It defines difficulty in accessing side branch. If this angle more can be ↓ by guide wire
insertion, which facilitates SB access after MB stenting.
B ( between) – between the two distal branches. If it small independently predicts SB
occlusion after MB stenting

Possible locations
LAD – diagonal
LCX – obtuse marginal
RCA – PDA
LMCA bifurcation

INCIDENCE
Account for 16% PCI
Procedural complications – 9%
Restenosis as high as 36%
Lower initial success rate

Technical problems
Difficulty in access to the side branch
Plaque shift
Lesion recoil
Ineffective lumen expansion
High periprocedural complication rate
Sub optimal immediate and long term results
Risk of side branch occlusion

Anatomical Considerations
Y-angulation precise stent placement with complete ostial coverage is
often difficult or geometrically impossible.

The outer walls of bifurcation points are subjected to
diastolic flow reversal, which leads to oscillatory shear
stress.
Oscillatory (as versus laminar) shear stress is less
efficient in stimulating eNOS.
Monocytes bind more avidly to areas of oscillatory shear
than to areas subjected to linear shear.
 oscillatory shear stress is proatherogenic
The shear stress hypothesis
Hsiai, T.K et al ATVB 2001; 21: 1770

ClassifiCation of bifurCation lesions

Limitations of Medina classification
Does not take into account
1. Length of disease in the ostium of the SB
2. Length of the LMCA before the bifurcation
3. Trifurcation
4. Vessel angulation
5. no differentiation is made between a normal segment
(lesion free segment) and a <50% lesion
6. presence of calcifications is not identified

Mohaved classification
Mohaved classification
Movahed
classification

Provisional stenting versus eleCtive double
vessel stenting

Major adverse cardiac event (MACE) and TLR incidence in
randomized trials comparing 1-stent (1S) with 2-stent (2S)
strategies.

MAIN BRANCH RESTENOSIS RATE AFTER DES

SIDE BRANCH RESTENOSIS RATE

BASIC PRINCIPLES
 Ramifications of coronary tree follow minimal energy cost in
providing myocardial blood flow.
Relation between 3 diameters is simplified by Finet.
Dprox = (Ddistal + Dside) x 0.678.

OPTIMAL VIEW
SB ostium is rarely visualized from 2 orthogonal views, and may be
explored from single angle called working view.
For LMCA – RAO or LAO view with caudal inclination.
For LAD – D : AP with marked cranial angulations.
For LCx – OM : slight LAO or RAO with caudal angulations.
For distal RCA : AP with cranial angulations.

Guide selection
A 6-F guiding catheter can be used if the operator performs a
provisional stenting technique .
Techniques such as the T, the reverse crush, and the step crush
can all be used with a 6-F guiding catheter.
The modified T technique requires at least a 7-F guiding catheter.
Culottes, Y, V techniques require at least 8-F guiding catheters

ONE OR TWO GUIDEWIRES ?
GUIDEWIRE IN EACH BRANCH - improve patency of SB after MB
stenting.
It also good marker of SB origin in case of SB occlusion after MB
stenting.
It can also be used to reopen SB by pushing balloon over jailed guide
wire.
Best way to avoid SB occlusion – select MB stent diameter according
to distal MB diameter in order to avoid carina shifting.
Wire modifies angle A – thus facilitates guide wire exchange, balloon
& stent advancement.
TULIP – study use of one wire while starting the procedure is a
predictor of SB treatment failure.

BIFURCATION LESION – a)STENT SIZE ACCORDING TO DISTAL MB REFERNCE
b) STENT SIZE ACCORDING TO PROXIMAL MB REFERENCE RESULT IN CARINA SHIFT
CARINA IS USUALLY FREE OF ATHEROMA – risk of side branch occlusion is mainly
because of carina shifting ( rather plaque shifting), when MB stent size distal to bifurcation is
too large.

when a wire is needed in the SB?
1) the SB has a narrowing at its ostium.
2) the MB has severe stenosis with a large plaque
burden and the SB originates with an angle of <45°.
3) the ostium of the SB deteriorates after pre-
dilatation of the MB.

SHOULD WE PREDILATE SB LESION OR NOT?
Kissing balloon predilatation is not recommended because of risk of
extensive dissections in unstented segments.
Predilatation of MB left to discretion of operator based on type of
lesion.
Predilatation of SB is subject of controversy – better avoid.
DRAWBACKS - Because while dilating ostium dissection may develop
prevents access to SB across stent struts of MB stent.

PROXIMAL OPTIMISATION TECHNIQUE ( POT )
Provides solution to under deployment of proximal MB stent.
Carried out by short bigger NC balloon just proximal to Carina.
Changes the orientation of SB Ostium facilitating the insertion of
guide wire, Balloon & if necessary stent in the SB, as well as projection
of stents in the SB Ostium.
POT is useful in especially in bifurcation lesion with large SB.

IS KBI NEEDED AFTER SINGLE STENT DEPLOYMENT ?
KBI allows SB ostium treatment & apposition of MB stent struts on SB
ostium.
It also enables correction of stent distortion & inadequate apposition.
Drawbacks : Procedural complexity , stent ovalisation, proximal
dissection.
Final KBI is strongly recommended after complex technique with two
stents, remains controversial in case of single stent.

HOW TO CARRY KBI APPROPRIATELY ?
Step 1: Insert a free wire in SB through struts of the MB stent, if
possible closest to the carina.
Pre shaping of MB wire, utilisation of POT , use of hydrophilic or
more rigid wire & orientable micro catheter may help.
Hydrophillic wires should not be jailed.
In persistent difficulties advancement & subsequent inflation of very
small balloon over jailed wire may restore flow & help in crossing.
Step 2 : After insertion of free wire in SB, jailed wire must be
withdrawn.
Step 3: Selection of Balloons – Diameter must match 2 distal
branches. Balloons must be sufficiently short & use of NC balloons to
dissection.↓

Characteristics of bifurcations with difficult SB access
CAG predictors - severe calcifications,
 severe stenosis with a large plaque burden in the proximal MV,
tortuosity in the proximal MV limiting guide wire manipulations,
 severe stenosis of the SB ostium(TIMI flow <3) .
Distal bifurcation angle - is an important issue in terms of access to
SBs.
SB wiring is usually easy when angle is < 70°, while access more
difficult if angle > 70°, and can be particularly difficult when it exceeds
90°.
 Natural distribution 80±27° for LAD/LCX, 46±19° for LAD /D1, 48±24°
for LCX/OM1 & 53±27° for PDA/PLA, respectively.

Primary side branch wiring – non complex SB access
 J tip angle(L1) is usually modulated
according to the side branch take
off angle.
 Length of tip(L2) is usually adjusted
according to diameter of the main
vessel lumen.

It is usually advisable to wire the branch which appear more difficult to do.

Complex side branch access
When the problem is a distal wide angle ( LCx take-off from LMCA), a
useful solution is to shape the tip with a wide smooth bend or with a
double bend (later is being more practical when the SB lesion is
tighter).
when the SB take-off is ≥ 90 ° & the stenosis is sub-occlusive -
 Ante grade wiring, by pushing the wire directly into the SB.
 Pullback wiring.
Other methods for complex SB are - “reverse wire” & Venture
catheter.

Anterograde in MEDINA 1,1,1
(Wide angle & sub occlusive
SB)
Pullback wiring in MEDINA
1,1,1

Reverse wiring in 0,0,1 with
extreme angle > 150
SB wiring with VENTURE

Side branch re-wiring after MB stent implantation
The success in SB rewiring is the key point of bifurcation
interventions.
Now commonly accepted best way is to wire the side branch by using
a pullback rewiring technique.
Important is to obtain a curve sufficiently wide to let the wire scratch
the MV stent struts.
 When difficulty in rewiring changing either the shape of the guide
wire's tip or the guide wire in favor of stiffer or more hydrophilic ones.
Rewiring site may influence the type of MBstent distortion after SB
dilation, as crossing of the distal side cells of the MB stent is
associated to better ostium scaffolding & need of SB stenting.↓

When are two stents needed? Intention to treat
SB when they are relatively large in diameter (>2.5 mm) & territory of
distribution.
Have severe disease that extends well beyond the ostium (≥ 10-20
mm).
Have an unfavorable angle for re-crossing after MB stent
implantation.

1)Provisional
Mainvessel stenting ± sidebranch angioplasty
(Provisional) T-stenting, TAP,
REVERSE INTERNAL CRUSH, REVERSE CULOTTE.
2) elective
Culotte-stenting
Crush technique (reverse crush)
T TECHNIQUE AND TAP
V STENTING
Y STENTING(SKS technique)
Stenting of Bifurcation Lesions

DEFINITION OF PROVISIONAL SIDE BRANCH STENTING
Main objective is focusing on MB, while maintaining the SB patency.
Strategy is to deploy stent from proximal to distal segment of MB.
In some cases, stent is deployed from proximal segment of MB to SB
also called as inverted provisional technique.
Advantages –
 because of open nature optimally MB & Bifurcation are dealt with single stent.
 When necessary 2nd
stent can be used for SB with culotte or T stenting
technique.
 Procedure can be carried with 6F guiding catheter.

 RELETIVE SIMPLICITY .
 REQUIRING SINGLE STENT IN 80-90% OF CASES &
 RESULTING IN SIMILAR OUTCOME COMPARED WITH MORE COMPLX
STRATEGIES MADE THIS METHOD GOLD STANDARD.
 EVEN FOR THE LM STENTING AS BY SYNTAX DATA.
 Drawbacks –
 Difficulty in ensuring permanent access to SB.
 Potential problems in recrossig stent struts towards the SB in implanting 2nd
stent in the SB after stenting the MB.

Provisional stenting of Bifurcations:
place a stent in the MB
postdilate the MB stent
at high pressure
place a wire into the SB
results are evaluated
dilatation of the SB and
kissing balloon inflation

Double stenting techniques which are certainly more complex, time
consuming & expensive than provisional stenting.
None of the RCT’s studies showed a clear advantage for routine
double stenting over a provisional strategy.
Other side of coin is patients with complex bifurcation anatomy such
as large SBs with severe disease extending more than a few mm from
the ostium were not well represented in these trials.
There is still a need for an individualized approach to bifurcation PCI
& that 2 stents are still needed in 20-30% of true bifurcations .
elective double vessel stenting

The culotte technique

The culotte technique
It provides near-perfect coverage of the carina & SB ostium at the
expense of an excess of metal covering in proximal MB.
Best immediate angiographic result & theoretically it may guarantee a
more homogeneous distribution of struts & drug .
Can be used in all bifurcation lesions irrespective of bifurcation angle.
Open-cell stents are preferred when the SB diameter is >3 mm.
Disadvantages –
Complexity in the rewiring of both branches through the stent struts,
Not advisable if both branches are dissected after predilatation.

Culotte technique
Not advisable when there is large discrepancy in
vessel size between the proximal MB and the SB
because the proximal segment of the SB stent
will not attain good apposition to the vessel wall
of the proximal MB .
Conventional practice - challenged in the
Nordic Stent Technique Study, where the
authors recommended stenting of the MB first
to avoid acute closure of the MB.
This approach guarantees patency of the MB

The crush technique

The crush technique (SB stent crushed by the MB stent)
 immediate patency of both branches is assured & therefore it should be
applied in conditions of instability or when the anatomy appears
complex.
 should be avoided in wide angle bifurcations.
 Only SB has to be re-wired & not both branches as in culotte technique.
 The crush technique has evolved and is nowadays performed with less stent
protrusion into the MB (i.e., mini-crush) & mandatory 2-step FKI.
 crush” technique can therefore be considered as a sort of simplified “culottes”
technique
 The mini-crush may be associated with more complete endothelialisation and
easier re-crossing of the crushed stent.

1. Inability to wire the SB.
 Make Sure That The Wire Is Directed Towards The Distal
Part But Not The Proximal Part.
 If The Primery Guide Wire Failes Try Hydrophilic Wires. If
They Also Fail Consider Tapered Tip Wires(MIRACLE).
1. INABILITY TO PASS BALOON IN TO SB.
 USE COMPLIANT MONORAIL 1.5 MM BALOON.
 IF FAILS REWIRE SB THROUGH A DIFFERENT SITE
AND RE ATTEMT BALOON CROSSING.
 IF FAILS THEN USE FIXED WIRE BALOON SYSTEMS.
Potential failure modes of crush and suggested solutions

REVERSE CRUSH
TECHNIQUEmain reason for performing
the “reverse crush” is
to allow an opportunity for
provisional SB stenting

Step crush
The final result is basically similar to the one obtainedwith the “standard crush”
technique, with the only differencebeing that each stent is advanced and deployed
separately so that a 6 F guide may be used.

Dk crush
In the DK crush, kissing balloon (KB) inflation is
performed after crushing the SB stent with a balloon.
This technique facilitates access to the SB in addition to
optimising stent apposition at the SB ostium.

T- and modified T-techniques
The T-technique is the most frequently utilised to crossover from
provisional stenting to stenting the SB and is most suited to
bifurcations where the angle between the branches is close to 90°.
 associated with the risk of leaving a small gap between the stent
implanted in the MB and the one implanted in the SB.
In majority T-stenting technique is performed after MB & provisional
SB stenting for a suboptimal result or flow-limiting dissection in the
SB.

modified T-technique

V technique

SKS TECHNIQUE

V & simultaneous kissing stent (SKS) techniques
• Advantages –
 Access to both branches is always preserved during the procedure with no
need for rewiring any of the branches.
 V-stenting is relatively easy and fast.(ideal in emergencies).
• V-stenting is ideal for Medina 0,1,1 bifurcations with a large proximal
MB that is relatively free from disease & with a <90° distal angle.
• Reserve this technique for patients with a short LMCA free from
disease & critical disease of both the LAD and LCX ostia.

LIMITATIONS –
 balloon barotrauma to the proximal MB.
If a proximal stent is needed almost always the risk of leaving a small
gap.
final kissing inflation is performed there is no need to re-cross any
stent.
Generally try to limit the length of the new carina to < 5 mm.

2011 ACCF/AHA/SCAI Guideline for PCI

Favourable features for provisional stenting
in unprotected LMCA
inSignificant stenosis at the ostial LCX with
MEDINA 1,1,0 or 1,0,0
Large size of LCX with >2.5mm in diameter
Right dominant coronary system
Narrow angle with LAD
No concomitant disease in LCX
Focal disease in LCX

UNFavourable features for provisional stenting in
unprotected LMCA
significant stenosis at the ostial LCX with
MEDINA 1,1,1; 1,0,1 or 0,1,1.
 Diminutive LCX with <2.5mm in diameter
Left dominant coronary system
Wide angle with LAD
Concomitant disease in LCX
Diffuse disease in LCX

L.M.C.A. BIFURCATION STENTING

IVUS in bifurcation stenting
Determining anatomic configuration, selecting treatment strategy &
assessing final result are key factors in bifurcation lesion treatment
that may have a significant impact on acute and long-term outcomes.
Furukawa et al demonstrated that side branches showing at IVUS
diffuse plaque around the ostium with >50% stenosis were at higher
risk for occlusion.
SB occlusion was uncommon (<10%) after PCI if no plaque was
present at the side branch ostium.
Important role in the decision-making process when treating a distal
LMCA bifurcation stenosis.

IVUS guidance for bifurcation lesion PCI
IVUS can select the appropriate stent size and length as well as
guiding the most appropriate technique.
Helpful in optimally expand the stent avoiding stent under-expansion,
malapposition, incomplete lesion coverage & overstretch of stent
diameter.
“Incomplete crushing”, defined as incomplete apposition of side
branch or main vessel stent struts against the main vessel wall
proximal to the carina, was found in > 60% of lesions – mechanism for
high restenosis rate.
Therefore, optimisation of the result in the side branch is still the goal
even in the DES era

Impact of IVUS guidance on outcome
Park et al in 758 pts - non-LMCA bifurcation lesions : IVUS-guided
stenting significantly very late stent thrombosis in the DES group,↓
while it did not have any effect on TLR.
Stent under-expansion, incomplete lesion coverage, edge dissections
& longitudinal plaque shifting, which likely contribute to DES
thrombosis are often missed by CAG & are detected by IVUS.
 MAIN-COMPARE registry in LMCA lesions - undergoing PCI of the
LMCA, 77.5% were treated with IVUS guidance.
3-year outcome showed a strong trend towards a lower mortality risk
with IVUS guidance group.

FFR in bifurcation stenting
Bifurcation lesion is very unique as it is the only lesion in which
stenting is not better than angioplasty & even angioplasty is not better
than a “leave it alone” strategy.
CAG evaluation overestimates the functional severity of jailed SB
lesions in every step of the provisional strategy for bifurcation lesions.
FFR-guided provisional side branch intervention strategy is feasible &
effective.
Functional status of jailed SB lesions after DES implantation does not
change significantly during follow-up.

CAG evaluation is more difficult for bifurcation lesions due to vessel
overlap, angulations, stent struts across SB & image foreshortening.
It is technically difficult to perform IVUS or OCT in jailed SB lesions.
FFR can be easily measured in bifurcation lesions both before &
during intervention.
CAUTION - When FFR is measured for SB ostial lesions, the influence
of proximal & distal lesions should be considered.
If there is a significant proximal stenosis, FFR overestimates the
severity of SB ostial lesion.
In contrast, FFR underestimates the lesion severity when there is a
significant distal SB lesion.

Limitations of conventional bifurcation stenting
MV stent distortion by side access
Side branch and wire jailing
Side branch accessibility
Limitations in re-wiring, re-ballooning and stenting
of SB
FKI with danger of dissection
Wire crossings
Incomplete coverage of bifurcational area
Complexity, duration and contrast and X ray
exposure

Conclusion
Bifurcation stenosis pose a technical problem.
The complexity of the lesion treatment lies in SB.

:
Presence of gap between the 2 stents
Carina/ Plaque shifting from MB
Injury to SB ostium- excessive balloon artery ratio

Approach to coronary bifurcation lesions

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