Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3585_Библиотеки_им_академика_М_И_Перельмана
.pdf
ab c
a
b
c
d
Inflection point
Vessel lumen distal to the
1.6 Antegrade Approach
https://t.me/medicina_free
69
Fig. 1.101 Reasons for formation of an inection point. (a) An inec-
tion point forms in a guidewire when it passes through a winding microchannel in a CTO, especially if the channel is lined with calcied tissue.
(b) In an orthogonal projection, a guidewire that leaves the true lumen
inside a CTO and enters the subintimal space will be viewed as deviating from the predicted course of the target vessel. Once it has entered
the subintimal space, the tip of the guidewire will only advance tangentially to its initial direction. If you attempt to return such a guidewire to
the predicted course of the target vessel, it changes direction to the right
or left when viewed in an orthogonal projection. This is why an inection point is formed near the site where the guidewire enters the subintimal space. (c) If a guidewire enters the subintimal space at the entry of
an occlusion, an inection point will also be formed if an attempt is
made to return it to the true lumen. Imaging in two projections is useful
(essential) for detecting the inection point
occlusion
Fig. 1.102 If the guidewire enters the subintimal space. (a) A guide-
wire that is outside the true lumen at the exit of a CTO is found to have
abruptly changed direction (inection point) within the occlusion. (b)
You should withdraw the guidewire to the inection point and explore
to nd a new direction in which the guidewire can be advanced without
inection. (c) If the guidewire is blocked by hard tissue when its tip is
oriented in the direction opposite to that of inection, you should x the
tip at that point and perform small xed point rotations until the wire
advances. (d) If the wire advances without deviation or inection, it is
likely to remain in the true lumen. If the guidewire cannot be advanced,
you should replace it with another one that has a higher tip load and
manipulate the new guidewire in the same way
70
a
b
Guidewire with a higher tip load
a
b
c
https://t.me/medicina_free
1 Mitsudo’s PCI Techniques forCTO
when antegrade PCI should be switched to either of these
strategies largely depends on the interventionalist’s expertise
and on the angiography equipment that is available (monoplane or biplane). My opinions on these issues are summarized below.
Standard tip curve
1. If you are using monoplane angiography equipment, you
should switch from the antegrade approach to the retro-
grade approach earlier. With monoplane imaging equip-
ment, it is necessary to rotate the detector through 90
degrees repeatedly to assist ne guidewire manipulation.
Even if a retrograde channel appears to be a little difcult
to track, you should try collateral channel tracking and
attempt to cross the CTO by the retrograde approach,
Guidewire with a more acute tip curve
with the expectation that the guidewire can be advanced
through the true lumen even when manipulated with guid-
ance by monoplane angiography. It is safer to try to
accomplish PCI by the kissing wire technique or the
reverse CART technique using a continuous landmark.
Fig. 1.103 If the guidewire enters the subintimal space despite xed
point rotation (a). (b) Penetration should be reattempted after the guidewire tip is reshaped with a more acute second curve of the same size. If
this retry also fails, exchange the guidewire for one with a higher tip
load
2. If a calcied region can be used as a landmark, you can
continue trying to cross the occlusion with a single wire
for a longer time. If obvious calcication is found during
PCI, you should be more likely to switch to the retrograde
approach. If the calcication is obscured during pro-
longed PCI, you should try to use a second guidewire as a
new landmark.
3. If there is no calcication to use as a landmark, you
should try to correct the guidewire route several times. If
these attempts fail, you should then use the parallel wire
technique. Since a guidewire with a stiff shaft, such as the
Conquest Pro, is likely to create a large dissection in a
relatively soft vessel wall, you should switch to the
retrograde approach earlier whenever possible (after a
favorable collateral channel is found).
4. When it becomes difcult to obtain good images of the
vessel lumen distal to the occlusion on uoroscopy, you
should start retrograde PCI.
5. If a guidewire being manipulated in an old RCA ostial
occlusion enters a small side branch and goes outside the
Fig. 1.104 Blocking (a) versus trapping (b) of a guidewire tip. A
guidewire that is trapped can no longer be advanced, but will not enter
the subintimal space as shown in (c). After prolonged manipulation, a
trapped guidewire becomes difcult to withdraw, and forcible attempts
to withdraw it may cause disruption and retention of the coil within the
occlusion. Therefore, never persist with manipulation of a trapped
guidewire
vessel wall just distal to the entry point, you should
directly switch to retrograde PCI without considering the
parallel wire technique.
6. If a guidewire being manipulated in a long occlusion of
the RCA enters a small side branch and then goes outside
the vessel wall around Segment #3, where the anatomy of
the target vessel is absolutely unknown, it is better to
Selection of the Parallel Wire Technique or Retrograde
Approach and Timing for Switching to These Strategies
If the rst guidewire has reached the vessel distal to the CTO
(but is outside the true lumen) or if the rst guidewire cannot
be advanced further within a long occlusion, you should then
use the parallel wire technique or switch strategies to the
retrograde approach. Which strategy should be chosen and
choose the retrograde approach.
7. If there is no accessible collateral channel whatsoever, you
will have no choice but to use the parallel wire technique
via the antegrade approach. If there is only a very difcult
collateral channel, you should generally try for longer to
succeed with antegrade PCI.If collateral channel tracking
fails, there is no choice but to resume antegrade PCI.
a
b
1.6 Antegrade Approach
https://t.me/medicina_free
71
8. If both the retrograde approach and parallel wiring are
unsuccessful, you should attempt IVUS-guided crossing
of the CTO.
The situation is the same if there is a subtle island of
contrast medium within an occlusion. If the guidewire
has denitely reached the island, you should advance a
microcatheter over the guidewire to the island and then
perform tip injection and guidewire exchange through the
Manipulation in the Vessel Lumen Distal to the
microcatheter.
Occlusion
When a tapered CTO guidewire reaches the vessel lumen
distal to the occlusion, you will usually feel a sudden
decrease of resistance. A guidewire that has entered the
distal true lumen will advance without deection of the tip
when pushed forward slightly with its tip oriented medially
relative to the curvature of the vessel. If the tip is deected
when the guidewire is advanced slightly, the tip must have
deviated into the subintimal space or been blocked by protruding plaque, since the tip will never be deected if it
remains within the true lumen. Because of the shape of its
tip, a tapered CTO guidewire creates resistance when passing through a hard occlusion, and this may make it difcult
to determine whether the guidewire is in the true lumen or
has gone outside it. If you become unsure of this, you should
push the guidewire forward slightly while rotating it within
±90 degrees with its tip oriented medially against the curvature of the vessel. If the guidewire can be advanced without
deection of the tip, it must be within the true lumen. If the
tip is deected, it must be in the subintimal space or blocked
by hard plaque, and you should reattempt intimal tracking.
If the guidewire has successfully crossed a CTO through
the true lumen, but is likely to damage a tightly stenosed
segment distal to the occlusion (Fig.1.105a), you can perform tip injection and guidewire exchange without damaging the distal segment if a microcatheter can be advanced to
the distal lumen before the guidewire tip reaches the stenosis (Fig.1.105b). If the microcatheter is vigorously pushed
forward or pulled back over the guidewire, the tip of the
guidewire will also move forward and backward, potentially
causing damage to the stenosed distal segment. Therefore,
you should advance the microcatheter with a steady force
while rotating it to-and-fro until it crosses the lesion. To
facilitate penetration by the microcatheter, you may use a
very small balloon, but you should minimize its vibration
to suppress forward and backward movement of the guidewire tip. If a Tornus microcatheter has crossed the occlusion,
guidewire exchange can be performed, but not tip injection.
You should use the anchoring technique to stabilize the
guiding catheter and consolidate backup.
Using a child catheter (e.g., a GuideLiner) or deep
engagement of a guiding catheter as small as 5 Fr may help
to improve pushability.
Fig. 1.105 If a guidewire that has crossed a CTO through the true
lumen might injure a distal stenosed segment (a). A microcatheter
should be advanced over the guidewire to the coronary artery lumen
distal to the occlusion (b), and the guidewire should be exchanged for
one with a lower tip load and an appropriate tip curve
72
1 Mitsudo’s PCI Techniques forCTO
https://t.me/medicina_free
1.6.4.9 Setting aLandmark
Whether you are performing antegrade or retrograde PCI,
the presence of a landmark can provide assistance for assessing the anatomy of the target vessel and makes guidewire
manipulation much easier. Therefore, setting a landmark is
an important key to the success of antegrade PCI.
Calcication and subtle islands of contrast medium
are some of the landmarks that are often available within
or around coronary arteries (Table 1.6). Other potential
landmarks that become visible with injection of contrast
medium are collateral channels connected to the vessel
distal to the occlusion and side branches arising from the
occluded segment. Devices that are advanced toward the
occlusion and can be used as landmarks include a parallel wire and the tip of a retrograde guidewire. Among
these possibilities, calcication, a parallel wire, and the
tip of a retrograde guidewire are permanent landmarks that
will always remain visible and help to determine the distance from the guidewire being manipulated. I frequently
employ such permanent landmarks because of their great
usefulness.
The principle methods of manipulating a guidewire are to
orient its tip in the direction of the route through the occluded
target vessel determined from a landmark, rotate it within
±90 degrees (xed point rotation), and push it forward with
minimal force while seeking the direction in which it can be
advanced. If there is a soft central core inside a relatively
hard vessel or plaque, you should perform to-and-fro rotation (plane rotation) of the guidewire.
Table 1.6 Possible landmarks
Landmarks Natural Continuous
Calcication
Collateral angiography
Subtle islands of contrast
Side branch from the occlusion site (collateral
ow)
Parallel wire (seesaw wiring) ×
Retrograde wire ×
○ ○
○
○
○
×
×
×
○
○
Landmarks, Imaging Equipment, and Fluoroscopy
Angle
To maximize the detection of calcication, a high-resolution
cineangiography apparatus must be available and must be calibrated appropriately. I think that biplane cineangiography is
essential, and viewing in at least two orthogonal projections
is necessary for this purpose. Some sites of calcication can
be clearly viewed in one projection, but are hardly visible in
another projection that is orthogonal to the rst one. If the
main vessel and its side branch can be clearly distinguished
in one projection, the two vessels will overlap each other in
another projection that is orthogonal to the rst one.
Let us consider this point using the LAD as an example.
When the midportion of the LAD is viewed in two orthogonal projections, the AP+CR and LL+CR projections (see
Figs. 1.32 and 1.33), calcication is clearly visualized in
the AP+ CR projection and easily distinguished from the
Dg and SB.Therefore, calcication can be readily used as a
landmark in this projection. In the LL+ CR projection, the
LAD and the Dg overlap, as does calcication in these arteries. The difcult uoroscopic conditions of this projection
also make it hard to demonstrate calcication, but a calcied
area may still be used as a landmark, if recognizable. If there
is no recognizable calcied landmark, you can only check
whether the guidewire has deviated from the vessel lumen
distal to the occlusion based on the estimated route of the
true lumen. It is easier to navigate the tip of the guidewire
toward the coronary artery lumen distal to the occlusion in the
AP+CR projection. However, if the guidewire cannot reach
the true distal lumen, deviation from the true lumen can often
only be recognized in the LL+CR projection (Fig.1.106).
When using the parallel wire technique, you should attempt
to advance the second guidewire parallel to the route of the
rst guidewire in the AP+CR projection and should use the
LL+CR projection to explore whether the second guidewire
can be advanced through the true lumen from the proximal
segment of the occluded vessel (Fig.1.106).
Conversely, if the rst guidewire appears to be outside
the true lumen in both projections (Fig.1.107), you should
change the projections so that the guidewire is viewed as
being inside the true lumen in one projection, while it will
deviate more markedly from the true lumen in the other new
projection (Fig.1.108). If the direction of the guidewire is
corrected while using the latter projection, successful crossing of the lesion through the true lumen is more likely to be
achieved.
1.6 Antegrade Approach
https://t.me/medicina_free
73
a
c d
b
Fig. 1.106 Occlusion of the proximal LAD. (a) AP+CR image. (b)
LL + CR image. The rst guidewire was manipulated under uoroscopic guidance in the AP+CR view. The guidewire seemed to have
reached the LAD lumen distal to the occlusion in the AP+CR view
(c), but it was seen to have deviated upward considerably in the
LL+CR view (d). In this view, an inection point (arrow) can clearly
be recognized (e). Using the seesaw wiring technique, a second guidewire was advanced along the rst guidewire to a site just proximal to
the inection point. In the AP+CR view, the second guidewire that
was advanced in parallel with the rst guidewire was seen to be crossing the occlusion through the true lumen (f). In the LL+CR view, the
second guidewire was advanced around the inection point with the tip
oriented downward while performing xed point rotation to explore
for a blockage. After this manipulation, the guidewire was also seen to
cross the occlusion through the true lumen in the latter projection (g).
An enlarged view (h) clearly shows that the second guidewire has been
advanced without creating non-inection point, like that in the rst
guidewire
74
In Projection A, the
occlusion can be viewed
orthogonal to its
longitudinal axis
Projection B is orthogonal to
occlusion
https://t.me/medicina_free
1 Mitsudo’s PCI Techniques forCTO
e
g
f
h
Fig. 1.106 (continued)
Fig. 1.107 Guidewire direction relative to the distal true lumen.
Projections A and B are orthogonal to each other around the longitudinal
axis of the occluded target vessel. In both projections, the guidewire deviates from the true lumen. These two projections cannot show the maximum
deviation of the guidewire or the accurate location of the inection point
and therefore will not be useful for correcting the direction of the wire
Projection A around the
longitudinal axis of the
to Projection A around the
occlusion
In Projection A, the
occlusion can be viewed at
an angle orthogonal to
its longitudinal axis
a
b
c
1.6 Antegrade Approach
https://t.me/medicina_free
Projection B is orthogonal
longitudinal axis of the
Fig. 1.108 Guidewire direction relative to the distal true lumen.
Projections A and B are orthogonal to each other. These two projections may be obtained by modifying the projections shown in
1.107. Unlike the previous gure, the guidewire appears to be
Fig.
inside the true lumen in Projection A, but is outside the true lumen in
Projection B.The maximum deviation of the guidewire from the true
lumen can be viewed in Projection B, and the inection point is more
clearly recognizable. Using two such projections makes it easier to
correct the direction of the guidewire, irrespective of whether you are
employing a single guidewire or the parallel wire technique. While
keeping the rst guidewire in Projection A or advancing the second
guidewire along the rst one in this projection, you should explore for
a new route that runs to the left from near the inection point in
Projection B
75
generally accepted that obstruction by hard tissue (calcied
or brous plaque) in the true lumen often causes a guidewire
to deviate into the relatively soft subintimal tissue. While this
concept is not supported by scientic evidence, it has the following empirical background.
After being blocked by hard tissue, a guidewire may
slip and then go forward when pushed. This can suggest to
the interventionalist that it has penetrated a hard cap and
advanced into the distal true lumen. Although a guidewire
exhibiting such behavior occasionally does enter the distal
true lumen as expected, angiography almost always shows
deviation of the wire into the subintimal space. If the tip of
a stiffer guidewire is pressed up against the obstruction and
xed point rotation within ±90 degrees is performed, the wire
can often follow an intraluminal route through the occlusion
and eventually reach the distal true lumen.
1.6.4.10 Parallel Wire Technique
Choice oftheSecond Guidewire (Figs.1.109, 1.110,
1.111, 1.112, 1.113, and1.114)
If the rst guidewire runs through the subintimal space and
fails to reach the distal true lumen, you should use it as a
landmark and try to cross the occlusion with another guidewire. As the second guidewire, I always choose one with a
higher tip load than that of the rst wire. This is because it is
Fig. 1.109 Parallel wire technique. (a) The rst guidewire has devi-
ated into the subintimal space. You should only withdraw the microcatheter by using Nanto’s technique or a Kusabi catheter. (b, c) You
should insert another guidewire into the microcatheter and attempt to
nd the true lumen with the second wire while using the rst guidewire
as a landmark
76
ab
https://t.me/medicina_free
1 Mitsudo’s PCI Techniques forCTO
Fig. 1.110 CTO of the RCA
(Segment #1). Imaging of the
RCA segment distal to the
occlusion via a bridging
collateral. (a) LAO view. (b)
RAO view
a b
Fig. 1.111 The rst guidewire. At the exit point,
the rst guidewire deviates slightly rightward in the
LAO view (a), while it deviates leftward in the
RAO view (b)
ab
1.6 Antegrade Approach
https://t.me/medicina_free
Fig. 1.112 Enlargement of the LAO image shown in Fig.1.111. The
guidewire is suspected to have undergone inection near the point indicated by an arrow. The optimal guidewire route from the distal side of
the occlusion (solid blue line) probably starts from the distal true lumen
parallel with the rst guidewire and runs toward the proximal part of the
occlusion. It will cross the rst guidewire at some point and then will
approximate and reach the rst wire in the proximal true lumen. The
optimal guidewire route from the proximal side of the occlusion (solid
red line) is most likely to run downward just proximal to the inection
point, after which it will form an arch, cross the rst guidewire, and
then run slightly leftward
77
Fig. 1.114 The same PCI procedure shown in Fig.1.111. From Point
1in the RAO (b), the second guidewire could be advanced within the
true lumen. It crossed the rst guidewire around the inection point in
the LAO (a), as expected. Thus, a guidewire that deviates into the subintimal space often enters it at the most proximal inection point
Fig. 1.113 Enlargement of the RAO image shown in Fig.1.111. The
rst guidewire may have undergone inection at any of three points
(arrows). The optimal guidewire route will follow the yellow line if the
Seesaw Wiring (Fig.1.115)
If the rst guidewire eventually fails to penetrate a hard
obstruction in an occlusion, you should use it as a landmark and attempt to penetrate the obstruction with a slightly
stiffer guidewire. Instead of the parallel wire technique,
which involves withdrawing the microcatheter over the rst
guidewire and using it to advance the second guidewire,
rst guidewire underwent inection at Point 1, while the blue line indicates the optimal route for inection at Point 2, and the red line indicates the optimal route for inection at Point 3
you may advance the second guidewire through a second
microcatheter while leaving the microcatheter of the rst
guidewire in place (seesaw wiring). If the second guidewire
is also blocked by the obstruction, you should exchange the
rst guidewire for an even stiffer wire and then advance it
through the rst microcatheter to cross the CTO by using the
second guidewire as a landmark.
78
a
b
c
d
a
b
c
d
https://t.me/medicina_free
Fig. 1.115 Seesaw wiring, a parallel wire method using a second
microcatheter. The rst guidewire has deviated into the subintimal
space. You advance a second guidewire through a second microcatheter
(a). Seesaw wiring is successful if the second guidewire enters the distal true lumen (b). If the second guidewire also deviates into the subintimal space (c), you can easily try to advance the rst guidewire through
the true lumen (d). Before attempting this, you may want to exchange
the rst guidewire for one with a higher tip load if the rst wire is
thought to have an insufcient tip load
1 Mitsudo’s PCI Techniques forCTO
Parallel Wiring Through a Crusade Microcatheter
Here I will discuss the circumstances and reasons why a
Crusade microcatheter is useful for parallel wiring or for
penetrating the entrance of a CTO located in a side branch.
First, a Crusade microcatheter helps a second guidewire
to easily track a tortuous vessel. Second, the stiffness of a
Crusade microcatheter which has accommodated the rst
guidewire provides stronger backup for a second guidewire
(Fig.1.116a). Third, if the side hole of the catheter happens
to be oriented toward the side branch, the catheter can help
to control the direction of the second guidewire and provide
stronger backup to facilitate successful entry into the occlusion in the branch vessel (Fig.1.116b).
However, the short tip and great stiffness of the Crusade
tend to bias this microcatheter and make it rather difcult
to control (Fig. 1.116c–f). Accordingly, you may have to
carefully adjust the curve at the guidewire tip when using a
Crusade microcatheter. You may sometimes have to adjust
the curves at the tip of both the Crusade microcatheter and
the guidewire.
e
f
Fig. 1.116 Guidewire manipulation through a Crusade microcatheter.
(a) A Crusade microcatheter provides good backup in a relatively
straight occlusion. (b) The side hole of a Crusade microcatheter is often
medial to the rst guidewire that has entered a curved main branch. If
the side hole faces the ostium of the branch, it will provide considerable
assistance for a second guidewire to penetrate an occlusion in the
branch. However, if the side branch originates from the larger curvature
of a bend in the main vessel, the side hole of the Crusade microcatheter
will not always face the ostium of the branch (c & d). If the side hole is
oriented toward the occlusion, a second guidewire can be easily controlled through a Crusade microcatheter (e). If this is not the case, the
second guidewire becomes difcult to control as it needs to be manipulated from a more proximal point (f)
Соседние файлы в папке Библиотека им академика М.И. Перельмана