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2 Stenting ofBifurcation Lesions
2.3.4 SB Wiring
Shaping the Tip Curve of the SB Guidewire
If POT has not been performed, the tip of the guidewire for
the SB should be bent to an angle of 90° relative to its shaft,
and the curve should have a radius about 1.0mm longer than
the diameter of the distal MB (Fig.2.41a).
Fig. 2.41 Shape of the tip curve for the SB
guidewire. (a) Without POT: Optimal radius ≈
D
+1 to 1.5mm. (b) With POT: Optimal radius ≈
LAD
D
+1 to 1.5mm. D
LMT
Diameter of the LMT
diameter of the LAD; D
LAD
LMT
If POT has been performed, the tip of the SB guidewire
should be bent to slightly less than 90° relative to its shaft,
and the curve should have a radius about 1.0mm longer than
the diameter of the proximal MB (Fig.2.41b).
You should aim for the guidewire to cross the stent
through the most distal cell at the SB ostium so that the wire
comes into contact with the carina (Fig. 2.42). This minimizes the risk of jailing.
Optimal R DLAD 1 1. 5mm
R
DLAD
DLMT
DLCX
Optimal R D LMT 1 1.5 mm
R
Fig. 2.42 Point of stent wire crossing. (a)
Diagram of a bifurcation in a projection
perpendicular to the plane encompassing both the
MB and SB. (b) Diagram of the SB ostium in a
projection parallel to the axis of the SB.The blue
line and the blue dot indicate the optimal route of
the wire and the optimal point of stent crossing,
respectively. If the SB guidewire follows the route
indicated by the green line, KBI will cause injury
to the distal MB and the SB at the time of
dilatation. If the SB guidewire follows the route
indicated by the red line, KBI will result in SB
jailing. A guidewire following the red or blue route
can move about 1.2–2.5mm within the stent cell
when pushed forward or pulled back slightly. In
contrast, a guidewire following the green route can
only move less than 1mm and will feel stuck
(although guidewire maneuverability also depends
on the stent type and strut conguration)
b
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181
Conrmation of Wire Crossing Through the Most Distal
Cell at the SB Ostium
If the SB guidewire comes into contact with the carina when
advanced slightly in a projection that allows en face observation of the bifurcation, it can be considered to have crossed
the stent through the most distal cell at the SB ostium
(Fig.2.43). Although the shaft of the guidewire crossing into
the SB is not always biased toward the carina, its tip is often
biased toward the larger curvature of the SB when the radiopaque marker passes the SB ostium. If coronary angiography
is performed at this time and shows the tip of the guidewire
in contact with the carina, it conrms that the wire has
crossed the stent into the SB through the most distal cell.
Alternatively, the SB guidewire can be anchored at a very
small branch or dimple and then pushed slightly to bias it
toward the carina. If coronary angiography subsequently
shows that the guidewire is in contact with the carina
(Fig.2.44), this conrms that the wire has crossed the stent
through the most distal cell.
Thus, if the SB guidewire comes into contact with the
carina when pushed toward the larger curvature, it is reasonable to consider that the wire has crossed the stent into the
SB through the most distal cell at the SB ostium. Conversely,
if the guidewire does not come into contact with the carina,
the stent has jailed the SB, possibly to a signicant extent
(Fig.2.42). For accurate radiographic assessment of SB wiring, coronary angiography must be performed in the optimal
projection (as discussed above).
from guidewire mobility within the cell. If the SB guidewire moves forward and back at least about 1.2 mm
within a cell at the SB ostium and is in contact with the
carina, you can assume that the wire has safely crossed
the stent. In contrast, a virtually immobile SB guidewire
has probably crossed the stent through a cell distal to the
SB ostium (Fig.2.42).
If the SB guidewire crosses the stent through a cell distal
to the SB ostium, it may cause dissection at the carina. In
such rare cases, culotte stenting may be indicated.
a
b
1. If the SB guidewire does not come into contact with the
carina when it is advanced appropriately, you should
remove the guidewire and make another attempt to cross
the stent through the most distal cell.
2. If the SB guidewire crosses the stent through a cell that is
actually distal to the SB ostium, KBI may induce carinal
injury by the most distal strut (Fig.2.42). Whether or not
the cell is distal to the SB ostium can be roughly assessed
Fig. 2.43 Conrmation of crossing the stent into the SB.A guidewire
is advanced with its bias toward the larger curvature of the SB immediately after entering the branch. If the guidewire does not come into contact with the carina (a), you should reattempt crossing the stent by the
optimal route that brings the wire into contact with the carina (b)
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2 Stenting ofBifurcation Lesions
Factors That Prevent the Wire Crossing Through the
Most Distal Cell
1. Plaque shift or dissection (not carinal shift) caused by
MB stenting that leads to SB ostial stenosis (Fig.2.45a).
2. Severe tortuosity of the target vessel.
3. Using a suboptimal uoroscopy projection that misleadingly suggests a guidewire has crossed the stent through
the most distal cell at the SB when it has actually crossed
through a more proximal cell. This is often a problem in
LMT bifurcation stenting (Fig.2.45b).
If the SB perfuses a large territory or has a diame-
ter≥3.0mm, you should perform IVUS after KBI to check
whether the SB guidewire crossed the stent through the most
distal cell at the SB.If necessary, you should reattempt to
cross the stent into the SB through the most distal cell.
Fig. 2.44 Conrmation of wire crossing through the most distal cell at
the SB ostium. If an SB guidewire is anchored in a very small branch
(a) and then pushed forward (b), its proximal portion will be deected
toward the larger curvature of the vessel. If the deected guidewire
comes into contact with the carina, you may assume that the guidewire
has crossed the stent into the SB through the most distal cell at the
branch. If this does not happen, the guidewire has probably not crossed
the stent through the most distal cell. Therefore, you should reattempt
crossing the stent through a more distal cell
Fig. 2.45 Failure to cross the
stent through the most distal
cell at the SB. (a) After
stenting the central vessel,
dissection occurred in the left
vessel and interfered with
wiring it. The right vessel was
very tortuous and also
difcult to rewire. (b) The SB
guidewire appeared to have
crossed the stent into the SB
through the most distal cell on
coronary angiography, but
IVUS showed it crossing the
stent through a central cell.
Using a suboptimal CAG
projection led to this error
r rrrr r
pd ddddn
2
1222324
22
,
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Removing a Jailed Guidewire
I limit the stent balloon ination pressure to 14atm so as to
prevent failure to remove the jailed wire. I also limit the
ination pressure for POT (mentioned later) to 14atm. A
jailed guidewire should be removed after rst withdrawing
the Crusade catheter. Removing the jailed guidewire is usually easy, even after withdrawal of the Crusade catheter,
although there is some resistance. If a jailed bare wire proves
difcult to remove, you should advance a balloon catheter
over the wire and position the balloon near the proximal edge
of the stent (Fig.2.46). The balloon may facilitate removal of
the guidewire by reducing friction between the wire and the
wall of the proximal MB and by helping the jailed part of the
guidewire to become more coaxial with its proximal part.
With the aid of a balloon, you can usually remove a jailed
guidewire without too much difculty, but you may sometimes encounter great resistance. In this case, you should pull
the guidewire back strongly without pushing the balloon in.
By doing so, you can usually remove the guidewire without
deforming the stent. However, when using a PROMUS
Element stent, the proximal edge of the stent may be
deformed by the tip of a balloon catheter advanced along the
jailed guidewire. Some stent deformation patterns prevent
introduction of a balloon into the MB stent. When removing
a jailed guidewire, you should take care not to cause such
stent deformation. To overcome this potential problem, I recommend introducing a balloon into the MB stent before
removing the jailed guidewire (Fig.2.46). Even if the MB
stent becomes deformed, the previously introduced kissing
balloon can still be inated to achieve optimal stent apposition. Since balloons are absolutely required for subsequent
KBI, introducing a balloon into the MB stent does not complicate the procedure; the only difference is whether the balloon is introduced before or after removal of the jailed
guidewire.
a
b
Fig. 2.46 Removing a jailed guidewire trapped by a stent. A balloon is
advanced over the jailed guidewire (a) until it is close to the proximal
end of the stent to facilitate removal of the guidewire. When the guidewire is pulled back, the balloon may be pushed into the stent and deform
it. To avoid problems due to stent deformation, a balloon can be introduced into the MB stent (b) before removing the jailed guidewire. Even
if the stent becomes deformed, the previously introduced balloon can
still be inated to achieve optimal stent apposition
Kissing Balloon Ination (KBI)
To discuss the optimal size of the kissing balloons and the
optimal ination pressures for bifurcation stenting, let us
consider the equations that can be used to predict the diameters of the MB and side branch(es) and to calculate the
dilated diameter of the proximal MB after KBI.
Before performing KBI for bifurcation stenting, I have
used the following equation to calculate the dilated diameter
of the proximal MB after ballooning since around the
mid-1990s:
1. Area conservation equation (Fig.2.47)
where rp is the diameter of the parent vessel and rdn is the
diameter of the nth daughter vessel.
This equation was not intended to accurately predict the
diameter of one (parent) vessel from the known diameters of
two (daughter) vessels. Instead, it shows that performing
KBI for a bifurcation lesion always dilates the proximal MB
to a diameter that can be calculated from the sum of the
cross-sectional areas of the two balloons used. Neither this
equation nor Murray’s law (presented below) can accurately
predict the actual diameter of a blood vessel in the body
because the vessel may have undergone positive or negative
remodeling and because vessel size does not change in precise units of 0.25 millimeters. I reiterate that KBI actually
dilates the proximal MB to a diameter that can be calculated
from the sum of the cross-sectional areas of the two balloons
used. Therefore, if the proximal MB has a smaller diameter
than the calculated diameter, you should inate the kissing
balloons at a low pressure or use undersized balloons for the
MB and SB in order to prevent dissection of the proximal
MB.On the other hand, if the proximal MB has a diameter
equal to or larger than the calculated diameter, KBI may be
performed at a relatively high pressure. The primary aim of
using this equation is to raise awareness of the need to make
such adjustments to the size of the kissing balloons and the
balloon ination pressure. It should be noted that Murray’s
law (presented below) is quite useless for this purpose.
Indeed, this law is used to predict the normal diameter of
each occluded vessel at a bifurcation CTO.Even in that case,
the area conservation equation is needed to conrm whether
the proximal MB can be safely dilated by kissing balloons of
a size compatible with the predicted vessel diameters.
Needless to say, the optimal size of the balloon for POT
should not be based on the theoretical (calculated) diameter
of the proximal MB, but on the diameter observed by IVUS
or optical coherence tomography (OCT). At a trifurcation, it
is also easy to adjust the ination pressures for triple KBI by
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325259625625 21 5464
.. .. ...
R
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2 Stenting ofBifurcation Lesions
comparing the observed diameter of the proximal MB with
its predicted diameter after dilatation calculated from the
diameters of the three distal vessels measured by IVUS.If
the observed diameter is greater than the predicted diameter,
the ination pressure should be about 10atm. If the observed
value is smaller than the predicted value, the kissing balloons
should be inated at a low pressure of about 6atm.
For example, let us assume that triple KBI is planned for
a trifurcation lesion involving the LAD, the high lateral
branch (HL), and the LCX.If IVUS shows that the diameters
of the three branches are 3.0, 2.5, and 2.5mm, respectively,
the dilated LMT diameter triple KBI can be calculated as
follows:
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Assuming that the LMT diameter is measured as 4.7mm
by IVUS, POT may be performed by inating a 4.5-mm balloon at a high pressure (14–20atm), and triple KBI can be
performed at standard pressure (8–10 atm). On the other
hand, if the LMT diameter is 4.4mm, POT should be performed by inating a 4.5 mm balloon at a lower pressure
(≤10 atm), and triple KBI should be done by inating
2.25mm balloons in the HL and LCX and a 3.0mm balloon
in the LAD at the standard pressure (8–10atm) (√2.25
2
+2
.252+32=√19.13≈4.4). If the three kissing balloons are 3,
2.5, and 2.5mm in diameter, respectively, balloon ination
should be done at a low pressure of about 6atm.
md
Rmp
Balloon 1
Rb
Balloon 2
Ab1 Ab2
2
2
Fig. 2.47 Area conservation equation: R
of the proximal main vessel; R
2
2
R
=R
p
the side branch. Ab1 Area of balloon1. Ab2 Area of balloon2
2
+R
d1
; Rmd diameter of the distal main vessel; Rb diameter of
d2
diameter of the nth daughter branch.
dn
=R
mp
+R
md
2
. Rmp diameter
b
r
pd ddddn
1
2
3
4
//
.
r rr
mp md b
067..
..
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2. Murray’s law (Table2.2)
Murray’s law describes the diameters of a bifurcated tube
with a certain rheological friction coefcient that is used to
model a bifurcated human vessel. The equation is:
73
73
rrrr r
73
73
73 73////
where rp is the diameter of the parent vessel and rdn is the
diameter of the nth daughter vessel.
If there are only two daughter vessels, the equation can be
simplied as follows:
where rmp is the diameter of the proximal MB, rmd is the
diameter of the distal MB, and rb is the diameter of the SB.
However, I measure the diameters of the individual vessels
by IVUS and OCT to determine the size of each balloon for
POT and KBI, and I never used this formula to estimate them.
Murray’s law is also impracticable for triple KBI because
it requires complicated calculations. It is quite doubtful that
such theoretical values can be useful for bifurcation stenting.
The actual size of a patient’s vessel is not always rheologi-
cally optimal and often tends to be suboptimal due to vascular remodeling and plaque deposition. Despite these
reservations, I will discuss the use of this formula for predicting vessel size at a bifurcation before KBI.
According to Table 2.2, a vessel branching into two
daughter vessels of equal diameter (3.5mm) is predicted to
have a diameter of 4.7 mm immediately upstream of the
bifurcation (4.7
(7/3)
=37.00≈37.20).
KBI with two 3.5-mm balloons can be predicted to dilate
the proximal MB to a diameter of 5.0mm as follows:
22
35 35 24 50 25 050
.. ..
mm
Even if the diameter of the proximal MB is observed to be
4.7mm, the same as that predicted by Murray’s law, should
KBI be performed using two 3.5-mm balloons?
Based on the area conservation equation, it would be recommended to gradually inate the two kissing balloons at a
low pressure or to downsize one balloon to 3.25mm in order
to prevent injury to the proximal MB.This is why I recommend using the area conservation equation to predict the
dilated diameter of the proximal MB, rather than using a formula that just predicts the size of the MB at a bifurcation.
Table 2.2 Predicted size of the main vessel according to Murray’s law
f
as
2.25 13.26 15.11 17.23 19.61 22.28 25.23 28.48 32.03 40.06
2.5 16.96 19.08 21.46 24.13 27.08 30.33 33.88 41.91
2.75 21.20 23.58 26.25 29.20 32.45 36.00 44.03
3.0 25.96 28.63 31.58 34.83 38.38 46.41
3.25 31.30 34.25 37.50 41.05 49.03
3.5 37.20 40.05 44.00 52.03
3.75 43.70 47.25 55.28
4.0 50.80 58.83
4.5 68.86
5.0 42.75
5.5 53.40
6.0 65.42
2.25 2.5 2.75 3.0 3.25 3.5 3.75 4.0 4.5
6.63 8.43 10.60 12.98 15.65 18.60 21.85 25.40 33.43
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2 Stenting ofBifurcation Lesions
Delivery of Kissing Balloons
1. As kissing balloons, use a high-pressure balloon for the
MB and a balloon with a small soft tip for the SB.For
reasons of medical economy, the balloons that were
employed for pre-dilatation are generally reused.
2. In principle, the balloon for the MB is delivered rst and
then the balloon for the SB.This is because the MB stent
may be deformed during delivery of the SB balloon, and
such deformation may preclude subsequent delivery of the
MB balloon. Another reason is that the MB balloon can be
used to assist delivery of the SB balloon. While introducing a balloon into the stent, you should take care to prevent
unnecessary deformation of the stent struts by the tip of
the balloon or its irregular surface. This is particularly
important for 2-link stents that are prone to deformation,
such as the PROMUS Element and Nobori stents.
3. If the MB balloon cannot be delivered, you should clarify
whether this is because the balloon tip is being blocked by
the edge of the stent or because of excessive friction between
the shoulder or body of the balloon and the stent. You can
easily distinguish between these two causes. If the distal
balloon marker is several millimeters from the stent edge,
the rst cause is more likely, while if the balloon marker is
very close to the stent edge, the tip of the balloon must have
entered the stent and the second cause is more likely.
(1) Blocking of the Balloon Tip by the Stent Edge
To deliver a balloon into a stent, you should push the bal-
loon very gently and advance it very slowly. If the proximal
edge of the stent is in the proximal part of an ostium or at a
vessel angle, the tip of a kissing balloon or a post-dilatation
balloon may be blocked by the stent edge so that the balloon
cannot be advanced with minimal force. However, an attempt
to forcibly advance the balloon can easily lead to stent deformation. This risk is particularly high when the stent shows
suboptimal apposition in a proximal MB with a large diameter (before POT or KBI). If the balloon is advanced rapidly,
it can deform the stent immediately on coming into contact
with it. Stent deformation induced by the balloon may be
mild, such as slight disturbance of the stent strut conguration. However, the balloon can elevate one or more stent
struts, which may further inhibit balloon delivery and could
possibly result in catastrophic stent deformation. Continued
attempts to advance the balloon may also cause similar
severe deformation of the stent. To successfully deliver a
blocked balloon into the stent without deforming the stent
struts, you can use any of the following procedures:
1. Pull the balloon back to straighten the balloon shaft and
then push it in slightly. Never continue to push it strongly
into the stent.
2. Change the orientation of the guiding catheter to separate
the balloon tip from the stent.
3. Pull the balloon back a little (to straighten the guidewire)
and then immediately push it forward slightly.
4. Use the buddy wire technique (Fig.2.48a).
5. Use the buddy balloon technique (Fig.2.48b).
6. If even the buddy balloon technique is ineffective, keep
the buddy balloon in place and exchange the kissing balloon for a new low-prole balloon.
(2) Friction Between the Shoulder or Body of the
Balloon and the Stent
If the balloon has been used for pre-dilatation, you should
withdraw it into the guiding catheter and inate it at about
10atm inside the catheter. Then immediately deate the balloon and advance it into the stent again. If this procedure
fails to deliver the balloon, you should completely remove
the balloon and rewrap it. If the rewrapped balloon still cannot be delivered, you should try the buddy wire technique
(Fig.2.48a). After failure of this technique, you should use
the buddy balloon technique (Fig.2.48b). The buddy balloon technique rarely fails, but if it does, you should
exchange the balloon for a new low-prole balloon.
4. If the SB balloon cannot be delivered, never try to push
it into the stent forcibly either. When advancing a balloon across the stent into the SB, take great care as it
often causes severe strut deformation if it becomes
stuck. This is particularly the case with a stent having
few (or no) links, which is prone to marked deformation.
Use a balloon with a small soft tip for the SB.Considering
the possible need for rewrapping, choose a balloon that
is easy to rewrap. Anchoring is not recommended, or
rather is contraindicated, for delivering a balloon into a
stent with 0 to 2 links. Anchoring reinforces backup of
the balloon and allows it to be pushed too strongly,
inducing stent deformation.
5. If the tip of the SB balloon is blocked by a stent strut (the
distal balloon marker is far from the stent carina), you
should inate the MB balloon to a high pressure. This
will achieve better stent deployment and apposition,
facilitating delivery of the balloon into the SB.If this
method fails, check whether the balloon tip has become
frayed (see (8)).
a
b
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187
6. If the tip of the SB balloon has crossed the stent struts,
but its shoulder is blocked, you should inate the two
balloons at a low pressure (about 6atm) by using the
hugging balloon technique. After deating them, gently
advance the SB balloon (Fig. 2.49), and it will often
cross the stent struts. Several ination/deation cycles
of the two hugging balloons may allow gradual advancement of the SB balloon.
7. Repeated dilatation of the proximal MB by a largediameter balloon (POT) using the MB guidewire can
facilitate delivery of the SB balloon.
8. If the tip of the SB balloon cannot cross the stent struts,
withdraw the balloon and check whether its tip has
become frayed (Fig.2.50). Fraying is often too small to
identify by visual inspection. Continued use of a balloon
with a frayed tip will worsen the fraying. Forcibly pushing such a balloon forward will cause its tip to spread
open, further exacerbating the difculty in achieving
smooth advancement and increasing the risk of stent
deformation (one reason that anchoring the balloon is
contraindicated in bifurcation lesions). If fraying is
identied, never reuse the balloon without cutting off the
frayed tip (about 0.3mm) by using sharp scissors. This
markedly improves deliverability of the balloon,
although it removes part of the tapered tip, which suggests that fraying of the balloon catheter tip poses a
major impediment to delivery across a stent. Although
Although the tip of a rotatable balloon catheter may
be cut off obliquely, balloon catheters are generally difcult to rotate. Therefore, I always cut off the tip of the
balloon catheter at right angles to its shaft.
9. If the balloon catheter still cannot cross the stent struts
after its frayed tip has been cut off, exchange it for a new
one.
10. If the new balloon catheter also cannot cross the stent,
it is highly probable that the guidewire has not passed
through an appropriate cell. While keeping the guidewire in place, try SB rewiring with a second guidewire
along a new route with the aid of a Crusade catheter.
Then advance a balloon catheter along the second
guidewire that has crossed the stent through a different
cell to deliver it into the SB.If the rst guidewire actually crossed the stent through an appropriate cell and
the second guidewire has passed through the same cell
(although this cannot be veried by coronary angiography), the buddy wire technique may be effective.
Therefore, slowly advance the balloon catheter along
the second guidewire. This technique may be more
effective if the rst guidewire is pushed in slightly. If
the buddy wire technique also fails (although it is rare),
the last possibility is to deliver the smallest-diameter
balloon into the SB.After dilating the cell by inating
the balloon, it should be exchanged for a larger
balloon.
cutting off the tip of a device is not ofcially recommended, I often do this to avoid using a new balloon
catheter for reasons of medical economy.
A balloon catheter may become frayed at its tip while
In summary, when delivering a balloon into the SB, never
push the balloon forward forcibly so as to prevent stent strut
deformation and never use the anchor technique.
crossing stent struts, as well as when it is advanced through
a CTO.As shown in Fig.2.50, I cut the balloon catheter tip
at right angles, not obliquely to the shaft, for the reason
explained in Fig.2.51. Although it might seem that a balloon catheter with an obliquely cut tip will be easier to
advance, the resulting angle at the tip is usually oriented
toward the larger curvature of the guidewire during
advancement of the catheter (Fig.2.51a). Due to lack of
support from the contralateral side, the leading edge of the
cut tip tends to lift away from the guidewire, so the angled
tip is more likely to get stuck on a stent strut and subsequently become more severely frayed. Theoretically, a balloon catheter with an obliquely cut tip can easily cross a
stent if it is advanced gently and is pulled back slightly and
rotated at about 180 degrees before attempting readvancement after getting stuck (Fig.2.51b). However, it is uncertain whether a balloon catheter that has become stuck can
actually be rotated appropriately in practice.
Fig. 2.48 Buddy wire technique (a) and buddy balloon technique (b).
(a) Introduction of a new guidewire changes the environment for the
balloon tip and/or reduces friction between the balloon and the stent
struts. (b) If the buddy wire technique fails, advance a new balloon with
good deliverability over the buddy wire. This facilitates delivery of the
second balloon
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a
b
Tip of a balloon catheter
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2 Stenting ofBifurcation Lesions
Fig. 2.49 Handling an SB
balloon that has failed to cross
the MB stent (hugging balloon
technique). (a) The SB balloon
cannot cross the MB stent. (b)
SB and MB balloons are
inated at about 6atm using the
hugging balloon technique.
Ensure that the proximal marker
of the MB balloon is located at
the proximal edge of the stent,
because dissection may occur in
the proximal MB if the two
balloons overlap outside the
stent. (c) After both balloons are
deated, the SB balloon can
often readily cross the stent into
the SB. (d) Performing KBI
a
b
a
c
b
d
Stent strut
Guidewire
Fig. 2.50 Countermeasures for a frayed balloon tip. (a) The tip of a
balloon catheter has become frayed and deformed. (b) The frayed tip
(about 0.3mm) has been cut off a balloon catheter, so it has lost its
tapered end compared with an intact catheter (c). (c) The tip end of a
new balloon catheter that has been chamfered modestly. (d) Using
Cooper scissors to cut off the tip of a balloon catheter
c
d
Fig. 2.51 Balloon catheter with the tip cut obliquely. If the angle at the
balloon tip is oriented toward the lateral side (larger curvature) of the
guidewire during advancement of the balloon, the leading edge is more
likely to get stuck on a stent strut and become severely frayed (a). A
balloon catheter with an obliquely cut tip should be advanced gently. If
it becomes stuck, it should be pulled back slightly and rotated about 180
degrees before attempting readvancement (b). In practice, a balloon
catheter often cannot be rotated appropriately
ab
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Column 16 Balloon Rewrapping
To reduce resistance to the irregular surface of a rewrapped balloon, you should minimize irregularity by using the
protective sheath to cover the balloon as follows. Insert the stylet introducer for the sheath into the balloon catheter
from its tip under negative pressure, and slide the sheath over the balloon from the tip to reduce its prole. Rotate the
sheath while sliding it over the balloon to prevent balloon deformation and to facilitate coverage with the sheath
Column 17 Importance of the Correct Fluoroscopy Angle
When conrming the position of the tip of the SB balloon, it is important to use a projection that allows en face observation of the bifurcation. For example, the LAD-Dg bifurcation must be viewed in the LAO cranial projection, and not
in the RAO cranial projection. As shown in Fig.2.52, the distal marker of the balloon appears to be well past the carina
in the LAO cranial view but is only just beyond the carina in the RAO cranial view. It is very important to decide
whether or not the balloon tip has passed the carina because this determines the subsequent procedures.
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Fig. 2.52 Views obtained in different projections. The distal marker of the balloon appears to be well past
the carina in the LAO cranial view (a) but is only just beyond the carina in the RAO cranial view (b)
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