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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3585_Библиотеки_им_академика_М_И_Перельмана
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1.7 Retrograde Approach
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109
a
b c
de
Fig. 1.156 CTO of the RCA. An epicardial channel runs from the
atrial circumex branch of the LCX to the RCA.At a bifurcation, overlapping branches are difcult to separate in the RAO (a) and AP+CA
(b) projections. In the RAO+CA projection (c), good separation was
obtained, and a guidewire could be advanced into the channel. The
guidewire (d) and a microcatheter (e) successfully tracked the channel
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Fig. 1.157 Multiple septal channels to the LAD. It was difcult to
identify or isolate the best channel because multiple channels crossed
and overlapped each other
1 Mitsudo’s PCI Techniques forCTO
Fig. 1.159 A tortuous channel between septal branches arising in dif-
ferent directions, one from the posterior descending branch of the RCA
and the other from the LAD
ab c
Fig. 1.158 Two apparently independent branches. (a & c) RAO. b.
AP+CR.Multiple channels are seen, but all of them overlap the main
vessel for most of the route (a). You should isolate a channel in a differ-
ent projection that permits better separation from the main vessel (b)
and then return to the original projection that gives the longest view of
the channel (c)
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111
Fig. 1.160 A vessel that is
seen to not be a channel in a
different projection. In the
RAO+CA projection, the
two vessels encircled by a
dotted line appear to form
channels between common
donor and recipient vessels
(a). In different projections,
one of these vessels loses
continuity (i.e., it is not a
channel) (b & c)
abc
1.7.8 Guidewire Selection andHandling
forEach Channel Type
For tracking a collateral channel, it is better for a guidewire
to have a very low tip load, as soft a shaft as possible, and
good slipperiness. Currently, a Sion guidewire is my rst
choice.
Until the entrance of the channel is reached, a retrograde
guidewire needs a tip curve of a sufcient size for introducing
it into the channel (Fig.1.161). Once the retrograde guidewire has reached the entrance of the channel, you advance
it further with minimal force and attempt to track the channel to reach the artery distal to the occlusion. However, the
guidewire will often fail to track a small tortuous channel
and reach the distal true lumen because the tip curve is too
large or the wrong shape. Therefore, it is often necessary to
advance a microcatheter into the channel for an appropriate
distance and exchange the guidewire for another wire with a
different tip curve.
It is very useful to perform tip injection through the
microcatheter after withdrawal of the rst guidewire because
it can conrm tortuosity of the channel and continuity with
the distal true lumen without interference by overlapping
vessels (Fig.1.162).
For retrograde tracking of a collateral channel, the tip
of the guidewire should ideally be curved according to the
tortuosity and branching of the channel (Fig.1.163), but a
guidewire with a small tip curve is generally satisfactory
(Fig.1.161c).
To prevent entry into a side branch at the vertex of a small
acute curve when tracking a collateral channel, the guidewire may need to have a tip curve that is smaller and more
acute than the curve in the channel. A very small and tortu-
ous channel may be difcult to track with a guidewire that
has a 0.014-inch tip. Such a channel can often be tracked
by a tapered polymer-jacketed guidewire (e.g., an XT-R) if
the tip is shaped into a very acute curve. However, a tapered
guidewire has the potential to cause intimal injury, particularly during the phase of the cardiac cycle when the tip of
the guidewire whips to and fro extensively. Accordingly, you
should take great care when manipulating a tapered guidewire to track a collateral channel.
To track a channel with multiple small corkscrew-type
bends (Fig.1.164), it is recommended to make the tip exible by forming a small curve using a guidewire inserter
(Fig.1.165a & b) and to reshape the wire by using a 25-G
shaping mandrel to obtain the optimal curve at the tip
(Fig.1.165a→c).
When tracking a collateral channel, I generally keep the
following points in mind:
1. Use minimal force when advancing the guidewire into the
channel, and never push it hard.
2. Primarily view the channel in a projection perpendicular
to its longitudinal axis.
3. Always keep the tip of the guidewire parallel to the chan-
nel while advancing it, especially as it passes through an
acute bend.
4. Advance the guidewire with as little force as possible and
only when it is oriented in the correct direction.
5. Exchange the guidewire for another with more slipperi-
ness if the resistance is too great to advance it without
employing strong force.
Of these points, (3) and (4) should especially be followed
if it becomes difcult to advance the tip of the guidewire
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a
b
c
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1 Mitsudo’s PCI Techniques forCTO
in the correct direction. Obtaining images from different
uoroscopy angles often provides new information. Part of
the collateral channel that appears straight in one projection
may be seen to be tortuous in another projection orthogonal
to the rst (Fig.1.166), or it may be found that the guidewire has entered a small side branch. Moreover, the actual
branching point and direction of a collateral channel may be
different from those expected initially (Fig.1.167). Under
uoroscopic guidance in the optimal views for assessing
channel tortuosity and branching, you should optimize the
Fig. 1.161 Optimal guidewire tip curves for channel
selection. (a & b) To advance a guidewire from the main
vessel into a collateral channel, the wire should initially
have a tip curve that is of an appropriate size for the
diameter of the main vessel. (c) After reaching the
entrance of the collateral channel, the guidewire should
be reshaped to create a smaller tip curve in order to track
the channel with a smaller diameter
tip curve of the guidewire by viewing the reference image
and advance the wire in the desired direction with minimal
force while performing rotation to help it pass through the
channel.
In order to advance the guidewire when it has become difcult to move forward through the channel, you will need to
determine the correct course for the wire by viewing images
in other projections and intentionally orient its tip in that
direction. You should always remember never to forcibly
push a guidewire that has become difcult to advance.
Fig. 1.162 Tip injection. Injecting contrast medium from the guiding
catheter provides little information on the anatomy of the target channel
because many other overlapping vessels are also visualized (a).
However, tip injection from a microcatheter clearly visualizes the target
channel (b)
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Fig. 1.163 Epicardial channel from
the posterolateral branch of the
RCA.The tip of a microcatheter is
indicated by the arrow. The guidewire
needs to be reshaped to have
appropriate tip curves for the diameter
and tortuosity of the branch/channel to
be tracked. Initially, the guidewire
needs a relatively large curve at the tip
to select the right branch (a). When
advanced further, the guidewire needs a
small tip acute curve (b). Imaging by
tip injection provides clear information
about these requirements
113
Fig. 1.166 Variation of channel appearance in different uoroscopy
projections. A channel that appears linear in one projection (a) may be
tortuous in another projection (b)
Fig. 1.164 Corkscrew-type collateral channel. This channel could not
be tracked by a regular guidewire, but was tracked by a broken-tipped
guidewire (shown in the next gure)
a
b
Fig. 1.167 Variation of channel appearance in different uoroscopy
projections. A channel that appears to have no branches in one projection (a) may show a branch in another projection (b)
c
Fig. 1.165 Making a broken-tipped Sion guidewire. (a) A regular
curve is formed using the tip of a guidewire introducer. (b) The curve is
altered to a J-shape. (c) The curve is made less acute again by using a
25-G shaping mandrel
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Column 8 Sion Guidewire
1 Mitsudo’s PCI Techniques forCTO
As of March 2015, the Sion is the best guidewire for the abovementioned collateral channel tracking technique. A Sion
guidewire can successfully track a tortuous collateral channel as the shaft of its several centimeters long tip has optimal
exibility and slipperiness. To track a tortuous channel with tight bends, the guidewire needs to be exible up to the
tip if possible. Unfortunately, the actual tip of every guidewire is not exible as it has a brazed part about 1-mm-long.
If the tip of a guidewire is broken by bending it excessively (see Fig.1.165b), only 0.6–0.7mm of the tip remains
inexible, so the guidewire becomes able to track even a corkscrew-type channel with tight bends. Simply bending the
tip of the guidewire into a J-shape would rather increase the risk of causing vascular injury. Therefore, the bent tip is
straightened again, and the angles are smoothed to form a natural curve at the tip (see Fig.1.165c), creating a safe and
effective guidewire for collateral channel tracking. Figure1.168 shows an example of successfully tracking a tortuous
channel with a broken-tipped Sion guidewire.
A new guidewire with a completely exible tip has been proposed. This wire would have no core at its tip, and
consequently the spring coil would be much more exible, so it would have an overwhelming advantage over existing
guidewires for tracking a non-branching tortuous channel. However, if the channel has a side branch at the vertex of
one of its curves, would it be possible to control the guidewire and prevent entry into the side branch? In such circumstances, a guidewire with a core at its tip usually seems to have better performance. As is known by every interventionalist and is expected from the reason a vessel becomes tortuous, a tortuous vessel (especially an epicardial artery)
often has a side branch at the vertex of one of its curves. Recognizing such a side branch and navigating the guidewire
through the channel across the branching point are the keys to successful collateral channel tracking.
Fig. 1.168 Successful tracking of a tortuous channel by a broken-tipped Sion guidewire
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1.7.9 Conrmation ofChannel Penetration
artery have similar anatomy. In this case, advancing a micro-
catheter along the guidewire without conrming that the wire
When you think that the retrograde guidewire has reached
the lumen of the target coronary artery distal to the CTO,
you should perform retrograde imaging via other collateral
channels to conrm that the tip of the wire is in the distal
true lumen. A retrograde guidewire quite often enters a vein
or a cardiac ventricle (Fig.1.169a & b), probably via a preexisting stula. In particular, you may think a guidewire has
entered the artery lumen distal to the CTO although it has
actually entered a vein if the vein and the target coronary
has reached the distal true lumen will cause arteriovenous
disruption at the stula, resulting in pericardial hemorrhage.
A guidewire that has tracked a collateral channel may reach
the lumen of a small vessel with very similar anatomical features to the distal true lumen. Although you may be almost
certain that a retrograde guidewire has reached the distal true
lumen without performing angiography, you should never
fail to perform contralateral imaging to conrm this before
advancing a microcatheter along the guidewire.
Fig. 1.169 Conrmation of retrograde guidewire crossing by angiogra-
phy. The guidewire seems to advance toward the septum in the RAO
view (a), but it shows considerable deviation toward the LCX in the
LAO view (b). The guidewire appears to have reached the posterior
descending artery via a septal branch (c), but tip injection demonstrates
that it has actually entered a vein running parallel to the artery (d)
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1.7.10 Advancing aMicrocatheter into
theDistal True Lumen
After a retrograde guidewire has crossed a collateral channel,
you should advance a microcatheter into the true lumen distal to the CTO.A microcatheter can often be advanced easily through a relatively large and less tortuous channel, but
frequently will not track a small tortuous channel so well. In
the latter situation, the microcatheter will often be easier to
advance if it is rotated and pushed simultaneously. However,
most microcatheters have a thin shaft and cannot tolerate too
much rotation, while the microcatheters with a shaft thick
enough to tolerate rotation often fail to penetrate a channel
because of their large diameter.
To enable a thin microcatheter to track a collateral channel, you should advance it while alternately performing
clockwise and counterclockwise rotation a limited number
of times. For example, you can perform three clockwise rotations and then three counterclockwise rotations to reverse
the torque back to neutral, after which you can perform an
additional three counterclockwise rotations (six counterclockwise rotations in total). This may be followed by six
clockwise rotations and then another six counterclockwise
rotations and so on. Such rotation is performed to reduce
friction, and not for achieving a large screw effect as with a
Tornus microcatheter.
If this maneuver does not help the microcatheter to pass
through the channel, you may introduce a small-diameter
balloon catheter. For this purpose, a small-diameter balloon with a small tip prole and a soft tip is naturally better.
Whether the balloon should be inated to dilate the channel after it has been advanced depends on the risk of cardiac tamponade due to coronary artery perforation following
balloon ination. A ventricular septal branch can be safely
dilated by a balloon, but the epicardial part connecting the
septal branch with the true lumen distal to the CTO should
not be dilated by the edge of the balloon, and the body of the
balloon should be used (Fig.1.170). Dilating an epicardial
channel with a balloon is associated with a risk of cardiac
tamponade, and forcibly pushing a balloon catheter into the
epicardial channel further increases this risk. Rather than
attempting to force a large balloon catheter into an epicardial
channel, it is safer to pass a balloon catheter with a smaller
tip prole through the channel without pushing hard and then
inate the balloon at a low pressure within the channel.
If the balloon catheter fails to cross the collateral channel,
you should search for another trackable channel while keeping the guidewire that crossed the rst channel in position.
If there is no other trackable channel, you should position
the tip of the retrograde guidewire near the distal end of the
occlusion as a continuous landmark to assist antegrade wiring. Such a continuous landmark will considerably increase
the probability of successful antegrade crossing of the CTO.
If a microcatheter crosses the collateral channel, you
should advance the retrograde guidewire and then the microcatheter to near the distal end of the CTO.If there is a side
branch near the distal end, it is better to introduce the retrograde guidewire into the side branch. This is because if
the retrograde guidewire remains near the distal end of the
occlusion, it will often go forward together with the microcatheter when the microcatheter is advanced. This may lead
to knuckling of the guidewire tip so that it readily deviates
into the subintimal space near the distal cap of the occlusion
(Figs.1.171 & 1.172) and will preclude retrograde intraluminal crossing of the CTO.
Fig. 1.170 Balloon dilation
of a collateral channel that
could not be crossed by a
microcatheter. When dilating
the part of the channel
indicated by a dotted line,
great care should be taken not
to cause perforation as this
may lead to pericardial
bleeding
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Fig. 1.171 Advancing a retrograde microcatheter. The retrograde
guidewire should be introduced into a side branch near the distal end of
the occlusion (a). If a retrograde microcatheter is advanced without rst
doing so, the guidewire will deviate into the subintimal space near the
distal end of the occlusion (b)
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wires may also be used, depending on the hardness of the
lesion. If it becomes trapped in plaque or the vessel wall, a
guidewire from the Gaia series is more likely to be deformed
or even fractured than a 0.014-inch guidewire or a Conquest
Pro guidewire. Therefore, you should take special care to
prevent trapping while retrogradely manipulating such a
guidewire. If it becomes impossible to move a retrograde
guidewire or advance it further, you should immediately
check if it can be pulled back and should then withdraw the
wire slightly before advancing it again. It is important to prevent the guidewire from being trapped.
If a retrograde guidewire becomes trapped in the tunica
media, you should follow the same procedure that was suggested for a trapped antegrade guidewire, i.e., rst advance
the tip of the microcatheter toward the point of trapping
while pulling the guidewire back slightly, and then rotate the
wire alternately clockwise and counterclockwise an identical number of times while continuing to pull it back with
minimal force. This maneuver should be performed with
patience. If the guidewire can be pulled back into the microcatheter, you should then direct it toward the proximal end of
the occlusion from a point just distal to the site of trapping.
It is important to be aware of the potential for deformation
of the guidewire tip by trapping and withdrawal (rotation).
You should withdraw the guidewire from the microcatheter
to determine whether its tip has been deformed. If the tip
becomes deformed, you should stop using the guidewire and
exchange it for a new one (see Sect. 1.9. “Troubleshooting”
[page 144]).
Fig. 1.172 CTO of the distal RCA (Segment #3). A retrograde guide-
wire that tracked a collateral channel to reach the distal end of the
occlusion was introduced into a side branch before advancing a retrograde microcatheter
1.7.11 Selection of (I) Guidewire, (II) CTO
Penetration Strategy, and(III)
Guidewire Handling Technique
The proximal cap of a CTO is generally harder than the distal
cap. As I always start PCI for CTO via the antegrade approach
and assess the hardness of the proximal cap before switching to retrograde PCI, I make my rst attempt at retrograde
crossing with a guidewire that is less stiff than that employed
for the antegrade approach. I commonly use a 0.014-inch
guidewire with a tip load of about 3.0g for the retrograde
approach and prefer a guidewire that is easier to control with
less probability of whipping. Tapered CTO crossing guide-
1.7.12 Direct Crossing Technique
Since I attempt antegrade PCI for CTO rst whenever possible, I rarely perform direct crossing of an occlusion via
the retrograde approach. Using the antegrade guidewire as
a landmark theoretically makes direct retrograde crossing a
subcategory of the kissing wire technique. In fact, manipulation of the guidewire for direct crossing is done in the same
way as in the kissing wire technique (see the next subsection).
When antegrade PCI is performed for a bifurcation CTO,
the antegrade guidewire may be unable to catch a dimple at
the proximal end of the occlusion. In this case, a retrograde
guidewire may be able to successfully cross the lesion (direct
crossing) if it is manipulated toward the tip of the antegrade
wire near the branching point. On the other hand, the antegrade guidewire often starts to cross the occlusion if it is
manipulated when the tip of the retrograde guidewire is near
the proximal end of the CTO, even if it is in the subintimal
space. Thus, PCI is often accomplished successfully by the
kissing wire technique or reverse CART (Fig.1.173).
Some CTOs can only be recanalized by the direct crossing technique. A good example is a CTO at a large coronary
ostium where an antegrade guiding catheter cannot catch a
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1 Mitsudo’s PCI Techniques forCTO
dimple at the proximal end of the occlusion. Only retrograde
PCI should be attempted for such a CTO, and if a retrograde
guidewire crosses the occlusion, it should be introduced into
an antegrade guiding catheter by using a snare (Fig.1.174).
a b
The optimum snaring point may be at the ostium of the target
coronary artery or in the innominate artery (Fig.1.175). To
perform snaring, you should use a snare ranging in size from
10 to 15mm.
Fig. 1.173 Successful recanalization of a CTO by the kissing wire
technique. After failure of antegrade PCI, the strategy was switched to
the retrograde approach (a). After a retrograde guidewire had almost
Fig. 1.174 CTO at the RCA
ostium. A retrograde
guidewire was captured with
a snare and introduced into an
antegrade guiding catheter
reached the proximal end of the occlusion, an antegrade guidewire was
manipulated again, and the lesion was crossed successfully (b)
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