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44 Guidewire skills
with a torque device and care taken to attempt to
cross a lesion or enter a vessel by turning the wire
in dierent orientations. Sometimes it is better for
the tip of the wire to be directed into the branch
and other times it is better if the tip of the wire
is directed away from the branch and have the
wire bounce o the opposite wall and land in the
branch. When crossing lesions, go gently with a
new guidewire choice to avoid creating false pas-
sages. If the guidewire itself cannot perform the
task at hand, the support structure for the wire
can be changed. e guidewire can be supported
with a catheter. Aselective catheter provides direc-
tionality and also sha strength to support the
guidewire tip. Aer repeating the same maneu-
vers with a better support structure, if success is
not at hand, change wires or modify the current
wire. If the guidewire needs more curvature,
this can be induced by manipulation of the tip of
the wire. Otherwise, a dierent wire should be
selected. In some cases more wire tip strength or
more wire sha strength may be required. Some
wires provide better directionality and responsive-
ness, where a rotation of the wire by the operator
results in an equal rotation at the tip of the wire,
and this may be required. In rare situations, the
initially selected support platform for the pro-
cedure should be changed and a dierent sheath
inserted and/or the tip of the sheath moved closer
to the lesion, where it can support the guidewire
better. Changing the sheath or moving the sheath
closer to the lesion may be considered if the guide-
wire and support catheter are not able to cross the
lesion.
USEFUL GUIDEWIRE TECHNIQUES
TO START TACKLING CHRONIC
TOTAL OCCLUSION
It is oen helpful to consider guidewire modica-
tion in the case of the worst morphology. One way
to do this is to create a loop and to use the loop of
guidewire to enter the subintimal space in order to
go around an occlusion or heavily calcied lesion
(Figure 4.10). Another method of modifying the
guidewire is to modify the tip of a chronic total
occlusion (CTO) wire. is creates an instrument
for drilling across the lumen of an occluded artery
(Figure 4.11).
Use a hydrophilic-coated guidewire, such as a
Glidewire
®
, with an angled tip. Some Glidewires can
be purchased with a loop already placed at the tip of
the wire. e rst few centimeters of the guidewire,
including the angled portion and its base, are soer
than the sha. e guidewire is advanced aggres-
sively with the tip into the lesion. At some point the
tip of the wire typically catches on the lesion and
the sha of the guidewire is advanced, forming a
loop (see Chapter 20, Figure20.2, for more detail).
Do not pass a loop with a hydrophilic guidewire,
unless you want it to be subintimal. is is usually
performed with catheter support and with the
tip of an angled catheter advanced all the way to
within a centimeter of the guidewire tip. If the loop
enters the lesion, the catheter support is advanced
to maintain the loop and allow it to advance. Once
the catheter is engaged in the lesion, pull back the
wire so that the tip of the wire that had been caught
in the opening of the lesion is freed. When the wire
is readvanced, the loop will follow. Once the guide-
wire has a loop, the size of the loop can typically
be controlled by advancing the supporting catheter.
A B C
Fig. 4.10 Modifying a guidewire by creating
a loop. (A) An angled Glidewire
®
, supported
by a catheter, is advanced to an occlusion. If
there is an opening to the occlusion, the tip of
the catheter is pointed there. (B) The tip of the
guidewire is advanced aggressively into the
occlusion. It initially bounces off the lesion but
at some point the tip will catch and the wire
is advanced. (C) If the guidewire tip does not
catch after several attempts (the lesion may be
quite hard/calcified), the catheter is advanced
to provide better support of the wire smashing
directly into the lesion.
https://t.me/med1917
Useful guidewire techniques to start tackling chronic total occlusion 45
Ifthe loop becomes too long or too wide, it will tend
to meander in a circular fashion around the sub-
intimal space. It is usually better to keep the loop
narrow. is can be done by keeping the supporting
catheter right behind the oppy portion of the wire
to support the loop directly and make the sha of
the wire a little sturdier.
Another method of dealing with dicult lesion
morphology is for the operator to create a drilling
guidewire. A low-prole (0.014-inch) hydrophilic
wire, such as a Command
®
Guidewire, is wiped
with heparin–saline to take advantage of the
hydrophilic coating on the tip of the wire. Low-
prole wires can be inserted with an insertion tool
that permits the wire to be advanced into a larger
caliber catheter (such as a 5-Fr catheter) without
catching on the inside of the hub of the catheter
and damaging the wire (Figure 4.11). e inser-
tion tool is advanced over the tip of the wire. With
approximately 2–3 mm of wire protruding beyond
the edge of the insertion tool, the index nger is
used to create a denite bend in the tip of the wire,
which is about a 45° angle. e insertion tool is
le on the wire and used to insert the wire into
the supporting catheter. e wire tip is advanced
to the lesion. It is best to enter the lesion with the
support of a catheter. e wire tip is rotated rap-
idly in one direction for several revolutions and
then the opposite direction for several revolu-
tions. Typically, the wire will make progress in the
intraluminal space in this setting. Frequently, the
bend at the tip of the wire can be seen to main-
tain its shape and when it gets to a section where
there is some space and freedom for the guidewire
to maneuver, the tip of the guidewire will oscil-
late just slightly, and this can be observed by the
operator using uoroscopy under magnication.
Change the rotation of the wire frequently so that
the tip of the wire does not become stuck. If the
wire tip reaches a stretch where the wire seems to
A B C D
EF
Fig. 4.11 Creating a drilling guidewire. (A) An insertion tool is a blunt-tipped, short hollow metal
rod that is used to assist the operator in placing a 0.014-inch wire into a catheter. (B) A 0.014-inch
CTO wire is advanced into an insertion tool and the wire protrudes from the end of the metal shaft
by 2–3 mm. (C) The forefinger presses on the transition from the shaft of the insertion tool and the
protruding wire. (D) This creates a definite sharp bend at the wire tip that can then be used as a drill.
(E) The wire is advanced to the occlusion with the support of a low-profile catheter, and then into the
occlusion using a drilling motion. (F) The wire is rapidly and circumferentially rotated to drill across
the occlusion. Usually the wire is rotated circumferentially for several revolutions in one direction, then
several revolutions in the opposite direction.
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46 Guidewire skills
be free and making great progress, you can speed
up a little bit, but it usually makes sense to con-
tinue making slow progress by rapidly turning
the wire, even when it is relatively easy. If the wire
seems to go in the wrong direction or into the
subintimal space, pull it back a little bit and start
again; it will oen take a dierent course.
ORGANIZING YOUR GUIDEWIRES
Several major companies make a full set of guide-
wires that cover the range of activities required in
endovascular therapy. e best way to proceed is
to look at several full collections, see what their
family of wires looks like, and then engage the one
that makes the most sense to you. You will need a
full quiver of 0.035-inch and 0.014-inch guidewires
and some 0.018-inch guidewires at a minimum.
Once you start learning using a full set of wires,
you will become facile. ere may be some task to
do or quality of wire you desire that has not been
met, in which case there is ample opportunity to
add specic wires to the inventory in a mix-and-
match fashion.
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47
5
Small platform guidewires and
monorail systems
DEVELOPMENT OF SMALL
PLATFORM GUIDEWIRES AND
MONORAIL SYSTEMS
Small platform guidewires with a 0.014-inch dia-
meter were developed to manage the smaller diam-
eter arteries of the coronary vasculature. Coronary
arteries range in size from less than 1 mm to 4mm
in diameter. Using higher caliber 0.035-inch diam-
eter guidewires and 4-Fr or 5-Fr catheters would
be severely limiting in the coronary circulation.
e routine use of 0.014-inch platforms in the
coronary circulation has been standard for many
years and, more recently, has been adapted for use
in the carotid, renal, and infrainguinal systems.
Tibial artery revascularization, in particular, only
advanced signicantly aer 0.014-inch systems
were adapted for use in this vascular bed. Small
caliber systems may be passed over the full length
of the catheter (coaxial system) or they may be used
with a monorail system. e coronary vasculature,
in addition to being small diameter, is remote from
major arterial access sites, such as the femoral and
upper extremity arteries. e monorail system, or
so-called “rapid exchange” system, helps to make
long distance passage of devices faster and delivery
more stable. How a monorail system works is illus-
trated in Figure 5.1.
HOW DO MONORAIL SYSTEMS
DIFFER FROM COAXIAL SYSTEMS?
e coaxial system has been the standard in the
noncoronary vasculature for decades. e system
is one in which there is a channel in the catheter for
the guidewire and that channel is present along the
whole length of the catheter. e guidewire goes
into a lumen that is visible on the tip of the cath-
eter, and the wire emerges from the catheter on the
hub end. is is a relatively stable situation because
the presence of the guidewire along the whole
length of the catheter confers a certain stiness,
support, and pushability to the catheter. During a
therapeutic procedure, such as balloon angioplasty
or stenting, the position of the sheath tip need not
be close to the target lesion for treatment because
the coaxial nature of the guidewire is usually suf-
cient to maintain stability. e disadvantages of
the coaxial system are: the presence of the guide-
wire over the whole length of the catheter causes a
lot more friction since the catheter and guidewire
are in direct contact with each other over a long
distance; the need for the internal position of the
guidewire within the catheter also raises the pro-
le of the catheter, making it just a little larger in
caliber; the wire lengths required are also longer
with the coaxial system. If the treatment site is
remote from the puncture site, this can become an
issue that exceeds existing guidewire lengths. An
example of this is when the access is at the femoral
and the path is up-and-over the aortic bifurcation
to a treatment site in the distal lower leg.
In the monorail system, the channel in the
catheter in which the guidewire is placed is along
a much shorter distance and is present only at the
leading end or tip of the catheter and ends along
the sha of the catheter. e guidewire goes into
a lumen that is visible on the tip of the catheter,
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48 Small platform guidewires and monorail systems
and the wire emerges from the side of the catheter.
e guidewire channel may be 5–30 cm in length
and much less than the total length of the catheter.
Monorail catheters are typically produced for the
0.014-inch and 0.018-inch platforms (Figure 5.2).
e monorail system works best when the sheath
tip, or guiding catheter tip that serves as the
platform, is close to the treatment site. If the mono-
rail catheter and wire travel separately for a long
dista nce outside the deliver y sheath, the pushability
is diminished when the catheter crosses the lesion.
In coronary procedures, the catheter is delivered
directly into the coronary artery by the guiding
catheter placed into the coronary ostium.
A
B
C
D
E
Fig. 5.1 Comparison of the coaxial and monorail systems. (A) The coaxial balloon angioplasty catheter
(top) has a guidewire lumen that is present for the whole length of the catheter. The monorail balloon
angioplasty catheter has a guidewire lumen that is present for only part of the length of the catheter.
(B) Close-up of the monorail balloon angioplasty catheter showing that the lumen for the guidewire
begins at the tip of the catheter and exits along the shaft. (C) The monorail catheter may be inserted
with one hand and the operator is also able to pin the guidewire with the other hand. (D) The front
end of the monorail catheter is inserted in the sheath and the catheter and guidewire are separate
going into the sheath; next, the left hand is used to hold the guidewire steady, while the right hand is
used to advance the catheter. The reverse of this maneuver can be used to remove the catheter. The
catheter may be removed for most of its length by holding the guidewire steady with the left hand and
withdrawing the catheter with the right hand. (E) When the catheter has been removed to the point
where the guidewire and catheter are joined together, the two-handed technique is used to remove
the remainder of the catheter. This is usually a short distance and the process is fairly quick, a lot faster
than the two-handed catheter removal technique along the full length of a coaxial catheter.
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Principles for the use of rapid exchange systems 49
WHAT ARE THE ADVANTAGES AND
DISADVANTAGES OF MONORAIL
SYSTEMS?
e monorail system gives the operator more con-
trol over the guidewire and makes it stable. e
monorail system has less friction, so the push-
ability of the catheters is faster and smoother.
Catheter insertion can be done more indepen-
dently since the operator can pin the guide-
wire without help from an assistant. Catheter
removal is faster since most of the catheter can be
removed in a single long pull without any guide-
wire manipulation. e “pin and pull” segment of
the catheter that takes longer to remove is much
shorter. e guidewires used for monorail sys-
tems may be shorter, as long as all the treatment
catheters intended for use in a given case are
monorail. e guidewire length required outside
the patient is not the whole length of the cath-
eter, but is only the length of the monorail seg-
ment along the catheter. An example of how this
works is in carotid stenting: with monorail sys-
tems, a 180-cm guidewire is used and if a coaxial
system is required, a 300-cm guidewire is used.
e sheath tip must be close to the target lesion;
this permits the monorail catheter and guidewire
to be close together and to be directed into the
target lesion. If the sheath tip cannot be placed
close to the lesion, as is sometimes the case with
infrainguinal interventions, the catheter may not
follow the guidewire aer it passes out of the end
of the sheath.
Coaxial systems are meant to travel over any
distance, even long distances, with the guidewire
as support. ese tend to be stable systems, as men-
tioned earlier. When a sti 0.035-inch guidewire is
used, or even a 0.038-inch guidewire, the system
is signicantly more stable. is larger platform is
the only option for delivering larger devices, such
as stent–gras for endovascular repair of abdomi-
nal or thoracic aortic aneurysms. When the cath-
eter is removed during a coaxial case, the operator
must perform the “pin and pull” technique, gradu-
ally removing the catheter from the patient and
taking great care to avoid removing the guidewire
or losing guidewire position. If it is a long catheter,
the “pin and pull” maneuver over a long distance
brings the operator further away from the monitor
and the patient.
PRINCIPLES FOR THE USE OF RAPID
EXCHANGE SYSTEMS
e monorail system is illustrated in Figure 5.1.
Aer the 0.014-inch guidewire is in its desired loca-
tion, the catheter is placed on the guidewire and
advanced to the hub of the sheath. e operator is
able to reach and pin the guidewire with one hand
and advance t he catheter with the other hand. Once
the catheter is in far enough that the monorail
segment of the catheter is inside the sheath, the
guidewire and the catheter will each be exiting
the hub of the sheath separately. e operator can
then use one hand to hold the guidewire, usually
stabilizing the sheath at the same time. e other
hand is usedto advance the catheter. Aer therapy
is complete, the catheter is removed by reversing
the order of events. One hand rests on the hub
of the sheath and pins the guidewire between
thethumb and forenger. e other hand retracts
the catheter until the location where the guidewire
and catheter join starts to emerge from the hub of
the sheath. Aer that, a short distance of “pin and
pull” is required. ere are many ways to perform
the “pin and pull” maneuver. e key is to nd one
comfortable for you so it is quick and smooth.
Fig. 5.2 Advantage of the 014 and 018 systems.
The 0.014-inch and 0.018-inch guidewires are
low profile and may be placed through a 4-Fr or
5-Fr angiographic catheter; this leaves space to
administer contrast or medication and still main-
tain guidewire access. A Tuohy-Borst adaptor is
used to secure the system, prevent backbleed-
ing, and permit contrast administration.
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50 Small platform guidewires and monorail systems
WHICH PLATFORM IS BEST FOR
EACH TASK?
Coronary interventions are performed using
guidewires that are 0.014 inches in diameter. is
is less than half the caliber of the 0.035-inch guide-
wires that have generally provided the platform for
most noncoronary interventions over the years.
In general, large vessel procedures such as aortic
and iliac procedures are performed with 035 sys-
tems (Table 5.1). Branch arteries such as carotid,
subclavian, renal, visceral, and infrainguinal
may be treated using either a large or small plat-
form. When a smaller caliber platform is desired,
it has not been well dened whether a 0.014-inch
or 0.018-inch platform is desired. is is still in
evolution; a signicant amount of development
has taken place in the 0.014-inch platform due to
its utility in the coronary vasculature, and much
of this technology has been adapted to peripheral
endovascular procedures. ere is recognition that
the 0.018-inch system has some advantages; for
example, a slightly more stable system allowing
more pushability against resistance. ere are some
tasks that are simpler with 0.018-inch platforms,
such as retrograde tibial and pedal puncture. ese
are discussed further in Chapter25. ere are also
0.010-inch wires that are used to treat complex
cerebral cases. ese are not generally used for
other endovascular procedures.
In general, branch vessel procedures are mov-
ing toward small caliber platforms. e lower
prole, the simplicity of the monorail system, and
the ability to place the guiding sheath close to the
lesion, all favor the use of small platform systems
for branch artery interventions.
WHICH PLATFORM SHOULD YOU
START THE CASE WITH, AND WHEN
SHOULD YOU SWITCH FROM ONE
PLATFORM TO ANOTHER?
In general, every case begins with the 0.035-inch
system. is is used to place the initial starter
wire and to create a rail that is large enough and
sti enough for a sheath to be placed. Once arte-
riography is completed and therapy planned, the
0.035-inch system is usually employed again to
facilitate placement of the sheath through which
treatment will be performed (e.g., up-and-over
sheath, antegrade femoral sheath, common carotid
sheath). Aer the treatment sheath is in place, the
operator makes an assessment as to which wire
platform is best for any given case. Table 5.1 oers
some ideas about the options. Many situations
are clear-cut. Carotid bifurcation stenting is per-
formed with small caliber systems and aortoiliac
stenting is performed with large caliber systems.
Some cases in the treatment of certain vascular
beds may be a “dealer’s choice” situation. In this
case the operator assesses two factors and imagines
these factors if the 0.035-inch system is maintained
or if the operator goes to a smaller caliber system.
ese factors are the likely stability of the sheath
and the probable maneuverability of treatment
devices.
For common carotid and innominate stents,
the 0.014-inch system provides a lot more exibil-
ity in terms of the availability of supplies and the
ability to pass the stent delivery catheter acrossthe
lesion, but the 0.035-inch system is typically a lot
more stable. e decision by the operator may
depend on the angulation that it will take to reach
the target. Subclavian stents provide a similar
challenge: stability of the platform versus maneu-
verability of treatment devices. Subclavian stents
may be placed transfemorally or through the bra-
chial artery, and this may also make some dier-
ence to the operator. Renal and visceral stenting
is facilitated by the use of a smaller caliber sys-
tem. e “no touch” technique becomes possible
with smaller caliber systems, but the stability of
the treatment platform may be questionable when
it is across a severe angle to enter the vessel (see
Chapter 22). For femoropopliteal intervention,
Table 5.1 Preferred platform for different
endovascular procedures
Intervention Platform
Carotid bifurcation stent 014
Common carotid,
innominate stent
014, 018, 035
Subclavian stent 014, 018, 035
Thoracic aortic stent–graft 035, 038
Abdominal aortic stent–graft 035, 038
Aortoiliac stent 035
Renal or visceral stent 014, 018, 035
Femoropopliteal
intervention
014, 018, 035
Tibial intervention 014, 018
https://t.me/med1917
Maneuvers you can undertake with 0.14-inch and0.18-inch guidewires 51
either a small caliber or a 0.035-inch system may
be used. Most of the appropriately sized treatment
devices, such as stents, are deployed on a 0.035-
inch system. ere are other considerations: the
experience of the operator, the operator’s prefer-
ences, and inventory considerations.
MANEUVERS YOU CAN
UNDERTAKE WITH 0.14-INCH
AND0.18-INCH GUIDEWIRES
ere are several maneuvers that the operator can
perform that are only realistically accomplished
with low caliber 014-inch and/or 018-inch guide-
wires. Smaller guidewires are ideal for small cali-
ber arteries. Neurovascular, coronary, tibial, and
pedal work, as well as small branch arteries of the
solid organs and visceral arteries, is only realistic
with 0.014-inch and/or 0.018-inch wires. Larger
caliber wires occupy a much larger percentage of
the lumen of a small caliber artery. When the dis-
tance and tortuosity and the wire bias are added
to the mix, the system comes to a grinding halt
when large caliber wires are used in certain vas-
culatures. ere are many very tight lesions and
occlusions that may be crossed with small cali-
ber guidewires, which allows the operator access
across the lesion. Once across with a small cali-
ber wire, the path is gradually enlarged, whereas,
the friction in a 0.035-inch system is signicant
and makes this task seem impossible. is is true
for drilling across an occlusion. It is also true
for a very tight stenosis, especially if the lesion is
long. Also possible with low caliber guidewires is
establishment of a buddy wire system (Figure 5.3).
Abuddy wire may be used to preserve access to a
branch, especially when a lesion is at or near the
branch point. A buddy wire may also be used to
stabilize a sheath. Distal lters are also based on
0.014-inch diameter guidewires.
A
B C
Fig. 5.3 Use of buddy wires. (A) A lesion near a branch point requires treatment and access to an
important branch must be maintained. In this example, a lesion near the femoral bifurcation requires
treatment, and the profunda femoris artery is protected by passing a buddy wire. This is done in
case of prolapse of disease into the profunda femoris artery origin during treatment of the lesion.
(B)Abuddy wire may also be used to perform simultaneous treatment of a lesion near a branch point.
In this case, a wire is passed into the posterior tibial artery and also into the peroneal artery to treat
a tibioperoneal trunk lesion that extends into both branches. (C) The buddy wire may also be used to
stabilize a sheath that is in a tenuous position. A length of buddy wire is passed into the subclavian
to allow a treatment wire and sheath to be stabilized for correct placement of a stent in the proximal
right common carotid artery.
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https://t.me/med1917
53
6
Handling catheters
INTRODUCTION TO CATHETERS:
EXCHANGE, FLUSH, AND
SELECTIVE CATHETERS
e simplest catheter is a vascular dilator. is is
a short (12–15-cm), slightly rm catheter with a
single hole in the end. A dilator is most oen used
to secure vascular access or to enlarge a percuta-
neous arteriotomy. When a diagnostic procedure
is converted to a therapeutic procedure, the arteri-
otomy must be enlarged by several French sizes. In
this setting, dilators are very helpful for control-
ling and safely enlarging the tract for sheath place-
ment. Occasionally, it is appropriate to perform
arteriography through a dilator (e.g.,femoral arte-
riography). An exchange catheter is straight and
long (at least 65 cm but may be up to 150 cm) and
is used to exchange one type of guidewire for
another. An exchange catheter may also be used
for interval arteriography to assess the results of
an endovascular procedure. A ush catheter is
used for general arteriography. It has an end hole
and it also has multiple side holes for high ow
administration of contrast. Flush catheter lengths
vary from 65 cm to 100 cm. e shape of the cathe-
ter head is usually rounded and promotes contrast
administration in multiple directions to create
a blush appearance during angiography. Flush
catheters are typically used in large vessels, such
as the aorta, under fairly high pressure, so that an
adequate bolus of contrast can be administered
quickly. Byrounding o the catheter head, there
is also less likelihood that the ush catheter tip
will scrape the vessel wall when it recoils from the
high-pressure contrast injection. Selective cathe-
ters have a multitude and nearly limitless number
of head shapes since they are used to direct a
guidewire into a specic location. Some selective
catheters were designed with specic arteries in
mind (e.g., carotid, visceral). All selective cath-
eters have at least one angle or curve at the tip and
some have two or three. Selective catheter choices
can be daunting but this can be simplied by clas-
sifying them into several categories.
WHICH ANGIOGRAPHIC CATHETER
SHOULD YOU USE?
Working with angiographic catheters in general is
marked by the dilemma of too many choices, rather
than too few. Catheters dier with respect to con-
struction material, diameter, length, head shape,
and special features. Each company that makes
catheters typically oers a full line-up of catheters
intended for various functions and for competition
with the other catheter manufacturers.
Construction
Angiographic catheters are constructed of poly-
ethylene, polyurethane, nylon, Teon™, or a
combination of these materials. Catheters made
of polyethylene have a low coecient of friction
and are pliable, have good shape memory, can be
torqued, and are useful for selective catheteriza-
tion. Polyurethane catheters are soer and more
pliable and follow guidewires more easily, but they
have a higher coecient of friction. Nylon cath-
eters are stier and tolerate higher ow rates, and
are useful for aortography and general arteriog-
raphy. Te o n™ is the stiest material and is used
mainly for dilators and sheaths.
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