How to Choose Hydrophilic guidewire?

2.1 Length

The selection of a guidewire with a correct length can be very relevant to adequately reach and treat the target vessel. For this decision, distance from the access to the vessel to be treated and the shaft length of the sheaths and catheters to be used (either if it is a diagnostic catheter, a balloon catheter, or a delivery device of a stent or a stent graft) needs to be considered. In fact, this apparently less relevant subject may threaten the entire procedure.

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Depending on the manufacturer, guidewires can range from 80 to 450 cm. Additionally, some guidewires may allow the connection of an extension during the procedure. This is particularly the case when a coronary guidewire is used as it is designed for rapid exchange devices.

There is a trick that can help in extreme circumstances and as bailout option only. During the removal of a catheter from inside the patient, it is possible to connect an inflation syringe device to the guidewire port of the catheter, just after losing the guidewire, and inflate inside the port, which will keep the guidewire in place. It is crucial to perform this maneuver under fluoroscopy as the guidewire may move forward and the external tip can even migrate and be lost inside the patient.

2.3 Stiffness

There is no clearly accepted nomenclature that can reproductively relate a word or a group of words to the stiffness of a guidewire. As so, it is possible to find several guidewires with the label stiff, extra stiff, super stiff, or even ultra-stiff, without any objective information of its real stiffness. Flexural modulus is an engineering parameter related to a wire’s resistance to bending (Figure 2). This measure is rarely displayed on the guidewire packaging or within the catalog [1]. Yet, it represents an objective method to quantify the stiffness of a guidewire.

This property is more frequently used to describe the body of the guidewire, but its use in the description of the tip of the guidewire can be very useful too. The stiffer the body of a guidewire is, the more support it will allow to deliver the intended endovascular devices to the target vessel. On the other end, a higher stiffness of the body reduces the ability of the guidewire to track the vessel tree. Concerning the tip, a higher stiffness increases the penetration capacity, but also turns the tip more aggressive to vessel wall increasing the risk of dissection or perforation.

3.4 Coating

Most of contemporary guidewires have a thin hydrophilic or hydrophobic coating applied at the final manufacturing process (Figure 4). Hydrophilic coating (e.g., polyethylene oxide or polyvinyl pyrolidone) needs water to be activated and to become slippery, but once wet, it allows an extremely low coefficient of friction [4]. As a result, it makes vessels easier to track and stenoses simpler to cross but leads to a decreased tactile feel, increasing the risk of dissection or perforation. Paradoxically, if a guidewire with hydrophilic coating gets dry, it loses lubricity and can get stuck, for instance, inside a catheter. Conversely, hydrophobic coatings (e.g., polytetrafluoroethylene or silicones) do not require water for activation [4]. As their name indicates, they repel water and create a smooth, “wax-like” surface [3]. Hydrophobic coating reduces friction but leads to a less slippery guidewire with enhanced tactile feel. Frequently, hydrophobic coatings are applied to guidewire bodies to facilitate movement inside plastic catheters [4]. Nevertheless, both coatings can coexist in a single guidewire, allowing their respective specific characteristics to be present either at the tip or throughout the body. In some configurations, even the tip can have both coatings, for instance, hydrophobic at the end for tactile feel and tip control purposes and hydrophilic intermediate segment for smooth crossing. Moreover, both hydrophilic and hydrophobic coatings may chafe or degrade with use [4]. This can account for the deterioration in wire performance at times noted during long procedures, particularly when wires are working through areas of severe tortuosity and friction or after numerous device exchanges [4]. This can even lead the guidewire to get fixed inside the catheter, forcing both devices to be removed as one piece, jeopardizing the therapy of the targeted vessel.

4.4 Shape, shapeability, and shape retention

Most of the 0.035″ guidewires used in peripheral interventions come in a preshaped format from the manufacturer. The more common available shapes are straight, angled, and J-shaped. The latter is the least traumatic. As so, it can be the best guidewire to use to deliver the intended devices to a target vessel. It can also be quite useful in tracking throughout a previously placed patent stent because the tip will not get stuck in the struts of the stent, neither will go between the stent and the vessel wall. Straight tips are more adequate to cross occlusions and angled tips to track vessels and to cross stenoses.

On the other hand, the vast majority of the 0.014″ and 0.018″ guidewires available for peripheral purposes comes in a straight shape and needs to be shaped. As so, shapeability characterizes the capacity of the guidewire tip to be angulated and shaped by the interventionist and shape retention represents its ability to maintain the intended shape over time [3]. These properties depend on the tip design and materials. Accordingly, a core-to-tip design with a core made of stainless steel is particularly easy and accurate to be shaped, but almost impossible to be reshaped. Conversely, nitinol core makes the tip more difficult to be shaped because it tends to return to its original form (memory) but is more reshapeable.

The tip of the GW can be shaped using the puncture needle (for moderately angulated curves), with the non-cutting edge of the blade (for sharp angulations) or with the inserter (for both) (Videos 1 and 2, https://bit.ly/3jPF7aj).

The desired shape depends on the primary purpose the guidewire will be used (Figure 10). Moderately angled continuous curves are very useful to track throughout the artery tree or to select a target vessel (Figure 10A). Several sharp angulations may help in selecting arteries with an acute takeoff such as the anterior tibial artery (Figure 10B). A very short sharply angled curve (usually no more than 1 mm) is intended to perform forceful and well-controllable drilling (Figure 10C).

5.1 Basic rules for guidewire manipulation

One of the best friends of a vascular interventionist is the torquer (Figure 11). It is the most proper manner to control the orientation of the guidewire tip. Therefore, its utilization is of utmost relevance in tracking difficult anatomies or in crossing challenging lesions (for instance, if the drilling technique is to be employed).

After having crossed the target lesion, the guidewire should be advanced very smoothly to the distal segment of the vessel. Confirmation through contrast injection that the true lumen has been reached after crossing the lesion is a basic but essential step. If a guidewire with a very aggressive tip was used to cross the lesion, it should be replaced by a much safer guidewire with good body stiffness for support (frequently the initial workhorse guidewire is adequate for this intent), sometimes after having shaped the tip as a loop (J-shaped like). During the delivery of the intended devices to the target lesion, it is of paramount importance to avoid inadvertent retraction of the guidewire, particularly after a complex crossing step and to prevent back and forth or shaking motion of the guidewire. That is why the tip of the guidewire should be on sight at almost all times. In summary, the two goals are: to secure the access to the target vessel and lesion; to avoid any trauma to the distal intact vessels.

5.2 Crossing the target lesion

The opening “workhorse” guidewire can be used in an initial attempt to cross the target lesion. Nevertheless, in many circumstances, a more dedicated guidewire will be required.

5.2.1 Crossing a stenosis

To cross a stenosis, it is perceptibly fundamental to stay intraluminal. For that purpose, the guidewire does not need to have increased stiffness, pushability, or penetration capacity. The tip should probably be hydrophilic as tactile feel is less relevant in those situations, and this can also improve the crossability of the guidewire. The tip is typically shaped in soft curve (Figure 10A), to be directed to the opposite direction of the stenosis. Specifically in tibial vessels, a 0.014″ guidewire can be preferable as in the case showed in Figure 1.

5.2.2 Crossing a chronic total occlusion

A chronic total occlusion is generally defined as an occluded artery of 3 months duration or longer [5]. When the vascular interventionist faces a chronic total occlusion, the best guidewire is obviously the one that successfully crosses the lesion. Nevertheless, there are several issues to consider in an attempt to cross a chronic total occlusion:

• The target artery. In fact, some arteries can be quite challenging to recanalize. For instance, an occlusion of the anterior tibial artery from its origin is, most of the times, very challenging to cross anterogradely because of the difficulty to engage the ostium. In those circumstances, adjuvant retrograde approach can be very helpful.

• The length of the occlusion. Longer occlusions are more difficult to cross and involve additional struggle to keep the guidewire in an intraluminal track. Moreover, the guidewire should have a stiffer body to support the crossing of a balloon or a support catheter, and it can also frequently require segmental pre-dilatations.

• The associated calcification. Depending on its length, location (entry point of the occlusion and/or in its core), and whether it is concentric or eccentric, calcification can greatly complicate the crossing of an occlusion or the reentry after a subintimal path. It also increases the risk of complications such as perforations or ateroembolization. On another hand, medial calcification can occasionally help in defining the limits of the vessel and consequently can guide the interventionist to stay intraluminal.

• Visible run-off. As a rule, the end of the chronic total occlusion should be clearly defined. Nevertheless, in some instances, such as in tibial vessels with very poor collateralization, it may not be initially adequately outlined and only appears after having crossed the occlusion.

5.2.3 Sliding technique

This technique is particularly indicated for engaging softer chronic total occlusions with microchannels [6]. It is frequently the first approach. For that intent, the initial “workhorse” guidewire with a soft hydrophilic tip and a body with some stiffness can be the option as reduced surface friction enhances passage through the chronic total occlusion core. The tip should initially be shaped in a single, long shallow bend (Figure 10A), and movement consists of simultaneous smooth tip rotation and gentle probing. But during the crossing, the interventionist should stay vigilant, as the guidewire has reduced tactile feel and typically advances with minimal resistance, frequently resulting in inadvertent entry to the subintimal space [7].

5.2.4 Drilling technique

If the sliding technique fails after a few attempts (one should not insist on this technique as it is easy to create several subintimal tracks that will jeopardize a desirable intra-luminal crossing), then the drilling technique should be tried. In this technique, a guidewire with a core-to-tip design with an uncovered tip should be preferred to enhance tactile feel. The tip is bended in a very short extension (Figure 10C) and clockwise and counterclockwise rotations of the guidewire are performed while the tip is pushed modestly against the chronic total occlusion (Figure 12). The important issue in this technique is that one does not push the guidewire very hard. Placing the balloon or the support catheter very close to the tip increases the penetration capacity. If the tip of the guidewire does not advance any more with gentle pushing, it is by far better to exchange for a stiffer tip and body guidewire, rather than continue pushing. If one pushes the wire hard, it will easily go into the subintimal space. Yet, when a stiffer guidewire is used, it may be difficult to perceive whether the tip has been engaged in the true or in a false lumen inside the chronic total occlusion. The movement of the tip may help in distinguishing one from the other. Typically, when the guidewire is in the subadventitial space, the tip budges markedly. Tactile feel from the guidewire during pullback can also aid as true lumen usually offers higher resistance. This technique has an increased risk of perforation, especially when using stiff tips guidewires [7].

5.2.5 Penetrating technique

The penetration technique comes next if the drilling technique does not succeed or when the interventionist has a chronic total occlusion with very calcified cap. In this technique, the preferred guidewires have a very aggressive tip (core to-tip design, uncovered tapered tip, with increased tip load, and a subsequent high penetration capacity) and a relatively stiff body. The tip shape is essentially straight, and a less rotational tip motion and a more direct forward probing is used in comparison to the drilling technique (Figure 13). Again, placing the balloon or the support catheter very close to the tip increases the penetration capacity and reduces the propensity of the tip to bend. Additionally, the distal target must be clearly identified and careful monitoring of the progressive guidewire advancement should be done. The guidewires employed in this technique should not be used to deliver the intended devices to the target lesion as the tip can easily damage the distally intact vessels. It is a technique with a particularly augmented risk of complications [7].

5.2.6 Subintimal technique

It is usually the last technique to be employed, even if it can be a first option in specific situations such as very long chronic total occlusions. For this technique, a guidewire with a stiff body and a soft short tip with hydrophilic coating is usually preferable. The short tip allows a short loop. After having created the loop, the guidewire is advanced to the end of the occlusion. To reenter into the true lumen, the loop has to be undone. Sometimes, the guidewire needed to be exchanged to a guidewire with a reduced diameter (if the initial guidewire was not a 0.014″ guidewire), with an uncovered tip (to increase the tactile feel and reduce the tendency to stay in the subintimal space that a hydrophilic tips has), a good torqueability, and an angled shaped tip (to be able to direct this one to the true lumen). Sometimes moving the balloon or the support catheter and the guidewire as one can be very useful (Video 3, https://bit.ly/3jPF7aj and Figure 14). If the loop, during the crossing, becomes too large, it means that most certainly, a perforation has occurred. In these situations, the guidewire should be retracted and an another subintimal track should be pursued.

5.2.7 Retrograde access

When the antegrade approach is not successful, a retrograde puncture may be required. Retrograde puncture of the popliteal artery is usually not a big issue. However, at below-the-knee level, since arteries are quite small and fragile and frequently the tibial or peroneal artery to be punctured is the unique artery to the foot, extreme care must be the rule. As so, after having performed the puncture with a 21G needle (either guided by ultrasound or by X-ray), a guidewire is to be engaged inside the artery. To avoid additional injury to the artery, the devices introduced in it should be kept at the strict minimum. That why usually it is most preferable to initially advance only the guidewire without any catheter or sheath (Figure 15). Therefore, the guidewire to be chosen needs to have a hydrophilic stiff body due to the lack of a sheath, the relevance of having adequate torqueability to guide the tip and to perform the snaring of the guidewire, and a potential need for an additional catheter if the guidewire does not reach the true lumen or the same subintimal track made anterogradely. A 0.018″ diameter guidewire is probably the best option as it is still a delicate guidewire, but with more support than a 0.014″ guidewire. The tip should be soft and most probably hydrophilic to track easily the punctured vessel retrogradely. As no sheath should usually be introduced, hard push on the guidewire can lead to irreversible kinging of its body, which can jeopardize the intervention.

5.2.8 Pedal plantar loop technique

This technique consists in creating a loop with the guidewire from the anterior tibial artery to the posterior tibial artery, or the reverse, through the foot vessels [8, 9]. The most common pathway is through dorsalis pedis artery, deep plantar artery, deep plantar arterial arch, lateral plantar artery, and posterior tibial artery. Indications for this technique are similar to the retrograde access. However, it can be performed when no distal vessels are available for puncture, being also less invasive. Moreover, this technique can improve the outflow for tibial arteries.

However, complications related to foot vessels manipulation can precipitate a serious worsening of the ischemic condition. Taking this into account, the guidewire to be chosen to this technique needs to have a soft hydrophilic tip to easily track through tortuous foots vessels without damaging them. The body should also have reduced stiffness to track across the created loop, that’s why usually a 0.014″ guidewire is preferred.

Guidewires were initially invented and used by Dotter and Judkins to cross a disease segment of the artery for further intervention. However, the initial wire used for coronary intervention was a spring coil guidewire over which a series of large rigid dilators were advanced.

Andreas Grüentzig replaced these dilators with inflatable balloons, which were introduced percutaneously, hence pioneering the era of percutaneous coronary angioplasty. After Grüentzig pioneered the first angioplasty, a group of cardiologists met and formed a registry under The National Heart, Lung, and Blood Institute. Since then, significant improvement in different types of equipment and techniques were made.

The original dilatation catheter with a short tip of guidewire could not be modified once the catheter was introduced, providing the operator with no control to maneuver the catheter/wire inside the vessel. In , Dr. Simpson developed a new catheter system with an independently steerable guidewire located in the balloon catheter’s central lumen, replacing the short fixed non-steerable wire tip (5 mm) manufactured by Andreas Grüntzig.1 The introduction of the coaxial steerable guidewire was the first revolution in the history of coronary angioplasty.

Compared to the early version of guidewires, modern guidewires are designed to combine tip softness, trackability around curves, and precise torque control, which allow the guidewire to be steered through tortuous vessels and side branches.

a) Wire Basics

The first step to understanding how to use a guidewire is to know the engineering aspects of wire technology, core material, and how different components change the wire’s characteristics. Guidewires are comprised of mainly four features: core, tip, body, and coating. The small variations in these components have drastic impacts on guidewire characteristics and their intended application. The areas that differentiate over a hundred guidewire are mainly due to various compositions at the wire’s distal end.

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Guidewire Components

PTFE = polytetrafluoroethylene

1. Core: It is the stiffest and innermost part of the wire. It provides stability and steerability and extends through the wire’s shaft from the proximal to the distal portion where it tapers.

• Core Material: The core is usually made of stainless steel, which provides excellent support with excellent torque transmission but is less flexible and not kink resistant. On the other hand, nitinol core, a super-elastic alloy of nickel and titanium, has more flexibility, excellent resiliency, and kink resistance. Newer wires (hybrid type) are made of stainless steel and nitinol distal tip for better torque transmission and excellent flexibility with kink resistance. (i.e., Runthrough, Minamo, Maestro, Spectre)

Stainless Steel

Nitinol

High Tensile Strength Stainless Steel

• Core Diameter: It is the part of the wire that tapers to the tip, not the wire’s overall size, and determines the flexibility (smaller diameter) and support (larger diameters).

• Core Taper: This is the part of the wire that extends from the core to the tip. The ability to transmit torque depends on the taper’s length; shorter tapers tend to prolapse but provide more support, while longer tapers offer less support but track successfully.

2. Tip: It is the distal tip of the wire. Various tip designs could affect the steerability of the wire.

• Core to Tip: Core extends to the tip of the wire. This design provides precise tip control and increases the wire’s diameter, enhancing the wire’s stiffness to help cross-resistant lesions.

• Shaping Ribbon: Core does not reach the distal tip of the wire but is wrapped in a ribbon of flexible metal to make the tip more flexible, atraumatic, and allows shape retention.

• Composite Core (CC) or Inner Coil Technology (ICT): Composite core (Dual Core and Dual coil) is made of multiple wire components to enhance durability and 1:1 torque transmission. The distal part of the composite core wire consists of core and twist wires, whereas the proximal portion of the wire is composed of rope coil, twist, and core wires.

Composite Core (Asahi)

Function of Rope Coil

1. Excellent Torque Transmission
2. Wire protection for durability

Function of Twist Wire

1. Allow smaller, more flexible core
2. Provide excellent tip durability

Inner coil technology is composed of a stainless steel inner coil affixed directly to the distal portion of the stainless steel core enhances the shape retention and durability of the distal tip, reduces whipping, and provides exceptional torquability.

Inner Coil Technology (Boston Scientific)

3. Body (Coil, Cover, and Sleeve): The body of the wire surrounding the core is usually made up of coils or polymers (plastic). Coils help maintain constant diameter, torque control, and tactile feedback. Various coil forming technologies have evolved in the contemporary era. Weaving multiple small wires into a coil is the most popular one, resulting in increased strength and a better torquability and torque response than a single coil.

   XTRAND Coil technology, used in Gaia Next series, is multiple wires braided together to create a coil, and the design avoids coil stretching, and its anti-trapping feature avoids coil damage.

Single Coil

XTRAND Coil

A polymer can either cover the distal spring coils or the core itself, providing a smoother surface for tracing tortuous vessels. A wire with both a polymer jacket and hydrophilic coating has an approximately 70% reduction in wire surface resistance when compared to an exposed coil and hydrophilic coating.

Hybrid wires, sometimes called sleeved wires, consists of a polymer cover on the body while leaving the distal spring coils at the tip uncovered.

Outer Coil ONLY

Tip Coil ONLY

Various Guidewire Construction based on different form of coils and Covers

Full Spring Coil Tip: Spring coil covering the distal core provides tip resiliency and tactile feedback.

Polymer Jacket over the Spring Coil: A wire with a polymer jacket covering over the spring coil: spring coil promotes tip resiliency while polymer jacket enhances crossability and smooth device tracking.

Full Polymer Tip: Polymer jacket covering the entire distal core’s length and facilitates crossability and smooth device tracking, especially in tortuous vessels. Spring Coil Tip with Polymer Jacket: Polymer jacket covers the entire wire except for the tip covered by Spring Coil, called hybrid design. The hybrid design increases tactile feedback and resiliency at the distal end while providing smooth device delivery. Micro-Cut Nitinol Sleeve: It provides efficient transmission of torque energy for more precise turn-by-turn response and control than conventional spring-coil guidewires. The nitinol distal core and hydrophilic coating are designed to enhance wire durability, tactile response, and device delivery for improved overall performance.

4. Coating: The wire body is coated by an overlay, a specific material that can reduce the surface friction and improve device interaction and guidewire tracking.

• Hydrophilic coating attracts water to create a slippery ‘gel-like’ surface when wet and non-slippery when dry. It reduces friction, increases lubricity of the wire that enhances tracking and crossing, although, on occasion, could unintentionally go into false subintimal spaces with increased risk of causing perforation.
• Hydrophobic wires are usually made of silicone and repel water to create a ‘wax-like’ surface, enhancing tactile feedback but decreasing slipperiness and trackability.
• Hybrid wire combines the hydrophobic tip for better tactile feedback with hydrophilic coating for smooth device delivery. In the contemporary era, the vast majority of guidewires have a hydrophilic coating. Put simply, hydrophilic wires increase lubricity, and hydrophobic wires increase tactile feedback.
• There are many proprietary coatings available in the market (e.g., M-Coat, Hydro-Track, or Slip-Coat (Asahi), etc.)

Terminology of different wires’ parts

Coil Length: The spring coil length can vary significantly from as low as 2.2cm upwards to 30cm. Generally, shorter coils are found on devices intended for high support and longer coils on trackability and flexibility devices.

Radiopaque length: The distal tip, an opaque part under x-rays, is usually about 30mm in length except for specialized CTO wires. It helps to make a measurement of the diseased segment and makes it easier to locate the wire. Some specialty wires have multiple radiopaque segments, such as the Medtronic Zinger Marker and Boston Scientific Forte Support Marker for more accurate measurements.

Small changes in wire design can have a large impact on the overall clinical performance. Thus, appropriate wire selection heavily depends on the understanding of the various wire properties. The following terminologies are often used to describe various guidewire characteristics.

1. Torquability: It is an ability to transmit rotating elements applied on the proximal end of the wire (outside of the guiding catheter) to the tip of the wire. It is the crucial determinant of the operator’s ability to steer the wire through the vessel precisely. An ideal wire should provide a 1:1 torque, which can be affected by core composition, tip stiffness, and surface coating.

2. Flexibility: Ability of the wire to flex on its longitudinal axis while maintaining its trackability and torquability. It is the critical determinant of the tip strength. Flexible wires are soft and generally atraumatic. A wire’s flexibility can be labeled extra floppy/light, floppy/soft, and stiff.

3. Shapeability: The ability to modify the guidewire’s distal tip before the procedure to access difficult anatomies or perform intentional drilling through a CTO.

4. Shape Retention: A wire’s ability to retain an intended shape after being exposed to deformation and stress. Different strategies improve shape retention, including Asahi’s composite core, which uses an additional coil and wire inside.

5. Nitinol wires such as Terumo’s Runthrough, as an inherent characteristic of the metal, have better shape retention than stainless steel.

6. Tactile Feedback: Any physical sensation felt through the wire’s proximal end during wire advancement inside the coronary artery. Hydrophobic coatings offer the best feedback, but such wires advance with more difficulty than slippery hydrophilic wires. An additional polymer sleeve could further reduce feedback.

Trackability or deliverability or crossing: It is an ability to follow the tip and advance smoothly along the vessel through stenosis or occlusion. Trackability is improved by nitinol core material and longer taper length, hydrophilic coatings, and polymer sleeves. Below, an Asahi Sion Black and conventional guidewire are advanced into an artificial vessel. Additionally, a comparison of guidewire surface roughness in a jacketed wire vs. spring coil wire is illustrated.

8. Tip Load: Tip load can be determined by advancing the wire into a standard surface until it deflects the tip, at 2mm from the tip. A high tip load can help when crossing a resistant or highly stenotic lesion, while a low tip load makes the tip very soft and atraumatic. Tip load is predominantly determined by core material and thickness, with stainless steel core-to-tip style used for the highest tip loads.

* There are various ways to measure the tip load depending on the manufacturer. The method shown here is used by Abbott.

9. Support: It is a measure of a guidewire’s resistance to a bending force. A more supportive wire can aid in device delivery and vessel straightening, while a less supportive one could assist in accessing tortuous anatomy. Support and propensity for wire prolapse are directly related.

10. Whip: A smooth torque input from the operator results in a sudden jerk at the wire’s distal end. This effect can be minimized through hydrophilic coatings and polymer covers/sleeves. In the chart below, the dotted line shows a whip response plotted. The y = x line demonstrates an ideal guidewire with a 1:1 torque response contrasted with the erratic whip visualized by the dotted line.

Input rotation at proximal end

Characteristics and Functionality of the Guidewires

Components
Function
Core
Stability, give tactile feedback, continuous force transmission and tip control
Components
Function
Tip
Steerability, provide direct force transmission and maneuvering
Components
Function
Body
Trackability
Components
Function
Coating
Hydrophilicity and trackability
Components
Function
No Coating Tactile feedback Workhorse
Nitinol BMW Runthrough Turntrac Versaturn Cougar Composite Core Sion Blue Dual Coil Samurai RC Stainless Steel HI-Torque Floppy Forte Floppy Choice Floppy Polymer Jacketed
Soft, Non-tapered Whisper Pilot 50 Fielder Sion Black Soft, Tapered Fielder XT, XT-A, XT-R Fighter Bandit Stiff Pilot 200 Gladius Mongo Raider Stiff
Gaia/Gaia Next Confianza Pro 12 Miracle Ultimate Hornet 14 Provia Astato 20, 40 Extra Support
Grand Slam Iron man Mailman CHOICE Extra Support HT Balance Heavyweight HT All Star Other
Wiggle Suoh 03 Externalization wires (RG3, R350) Rota floppy Viperwire

Knowing the properties of guidewire and the specifics of the different types are crucial in selecting appropriate guidewire. However, it is strongly recommended to choose and master only a few wires instead of having superficial knowledge about multiple wires.

1. Wire tip configuration and manipulation

The majority of guidewires are straight tipped and can be modified/shaped according to the vessel contour. The tip can be shaped with either the introducer needle or the shaping needle that comes along with the wire. Usually, a simple J shaped curve at the wire’s distal end will help track the wire through the vessel. The wire should be advanced gently through the stenosed segment. Forceful pushing of the wire can result in plaque disruption, leading to acute thrombus formation and occlusion of the vessel. It is recommended that 180-degree clockwise or counterclockwise rotations of the wire should be performed during advancement in order to avoid wire advancement into smaller branches.5 However, 360-degree rotations should be avoided, particularly when a second wire is required to prevent entanglement.

The wire tip should be placed as distal as possible, so the wire’s stiff part is across the lesion, providing adequate support to advance interventional devices.

2. Tip to wire specific blood vessel (LAD, LCx, RCA)

1. Left anterior descending (LAD)

The left anterior oblique (LAO) caudal view is the best initial view to wire the LAD. Once the wire position is confirmed in the proximal LAD, further advancement into the mid and distal LAD should be carried out in the right anterior oblique (RAO) cranial view.

2. Left Circumflex (LCx)

A broader tip helps with entry into the LCx, and a smaller curve supports advancement into the Obtuse marginal (OM).

3. Right Coronary Artery (RCA)

If the RCA’s origin is relatively normal, a conventional soft wire with good steerability to avoid side branches is chosen first.

3. Desirable Wire Characteristics

Workhorse
Safety
1:1 torque
Moderate support
Excellent tip shape retention
Durable / resist tip breakage
Frontline Finesse
1:1 torque
Excellent trackability through tortuosity
Single core
Moderate support
Low frequency of perforation
Avoid subintimal passage
Lubricity with tactile feedback Support
Provide more support for tortuous anatomy & distal lesions
Does not spring back
Soft gentle tip
Specialty
Variety of tip stiffness and/or tip tapers for excellent crossability
Tip shape retention
Moderate support
Low frequency of perforation

4. Non-CTO guidewire selection

1. Simple/Uncomplicated Lesion

• To treat simple, concentric stenosis of the artery, the vital element of the wire is safety.
• As these wires are not required to go through difficult or extreme anatomies, unique properties are not required.
• The wire should have an atraumatic tip, good torquability, and favorable trackability with a spring coiled nitinol wire.
• The choice of wires can include Runthrough, Balance MiddleWeight, and Sion Blue.

2. Tortuous Vessel

• In dealing with tortuous anatomy, the workhorse wires aren’t designed to tackle this challenging lesion and often fail to navigate through the lesion.
• The presence of wire’s flexibility, lubricity, and excellent trackability is essential to tackle this challenging anatomy.
• The optimal wire should have a soft tip, polymer/hydrophilic cover, moderate support, or a hybrid type with a hydrophilic body and hydrophobic distal tip.
• The choice of wires can include Fielder, Whisper, Pilot 50 and CHOICE Floppy.

3. Calcified Lesion

• Two distinct components are involved in wiring a calcific lesion: 1) crossing the lesion and 2) delivering the devices.
• The ideal wire to cross a heavy calcified lesion should have a soft tip with polymer/hydrophilic cover or a hybrid type of wire (hydrophobic tip and hydrophilic body). The wire choice can be Runthrough, Fielder, Whisper, and Pilot 50.
• To deliver PCI devices through a calcified lesion, the wire’s crucial characteristics include high support, good tactile feedback, and excellent torquability/trackability.
• The wires selection include Iron Man, Mailman, Hi-Torque Balance HeavyWeight, the Hi-Torque All-Star, or the CHOICE Extra Support with the buddy wire technique.

4. Bifurcation Lesion

• The guidewire properties to tackle a bifurcation lesion should include slipperiness, excellent trackability, and slightly stronger tip load. It is paramount not to choose those with a higher risk of wire retrieval damage (e.g., non-polymer-coated wires) as the wire might be jailed during the procedure.9
• The choice of wires for bifurcation intervention can include a workhorse wire (Runthrough, BMW, CHOICE Floppy) in the main branch and polymer-coated wire in the jailed side branch (Fielder, Pilot 50, Whisper MS).
• Occasionally, an aggressive wire with more tip stiffness (Gaia 2 or MiracleBros 3) along with a microcatheter may be required to enter the side branch in a challenging case.

5. Thrombotic Occlusion

• In a setting of an acute thrombotic lesion, the wire shouldn’t have significant resistance while traversing a lesion.
• The main objective is to cross the occlusion and advance the wire to the distal lumen softly and atraumatically.
• A soft wire would be the choice rather than a stiffer one with the hydrophilic or coated property. The operator can use any workhorse wire in this situation.
• In subacute occlusions, the thrombus material could have become more organized and may require a stiffer tip and higher tip load to facilitate in crossing the lesion. The wires choice can be Fielder, Gaia series, and MiracleBros 3.

6. Angulated Lesion

• The wire properties to navigate the angulated lesion is torquability, trackability, and wire flexibility. The ideal wire would be a soft tip with polymer jacketd and hydrophilic cover.
• Our choice of wires are Fielder, Whisper, and Pilot 50.
• However, we may require a stiffer tip with hydrophobic coating at the tip to have a better tactile feedback with torquability such as MiracleBros and Provia.
• Sometimes, we may require additional devices (i.e., angulated microcatheter or dual lumen catheter) to navigate an angulated lesion or when re-crossing a jailed side branch.

Polymer Jacket

Manufacturer
Tip Load
Properties
Fielder XT-R
Asahi Intecc
0.6
Stainless steel core, Tapered tip, Hydrophilic
Manufacturer
Tip Load
Properties
Fielder XT
Asahi Intecc
0.8
Stainless steel core, Tapered tip, Hydrophilic
Manufacturer
Tip Load
Properties
Fielder FC
Asahi Intecc
0.8
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Sion Black
Asahi Intecc
0.8
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Fielder XT-A
Asahi Intecc
1.0
Stainless steel core, Tapered tip, Hydrophilic
Manufacturer
Tip Load
Properties
Fighter
Boston Scientifc
1.2
Stainless steel core, Tapered tip, Hydrophilic
Manufacturer
Tip Load
Properties
Whisper LS, MS, ES
Abbott Vascular
0.8, 1.0, 1.2
Durasteel core, Hydrophilic
Manufacturer
Tip Load
Properties
Pilot 50
Abbott Vascular
1.5
Durasteel core, Hydrophilic
Manufacturer
Tip Load
Properties
PT Graphix Intermediate
Boston Scientific
1.7
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Choice PT Floppy
Boston Scientific
2.1
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Pilot 150/200
Abbott Vascular
2.7/4.4
Durasteel core, Hydrophilic
Manufacturer
Tip Load
Properties
PT2 Moderate support
Boston Scientific
2.9
Nitinol core, Hydrophilic
Manufacturer
Tip Load
Properties
Gladius
Asahi Intecc
3
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Shinobi Plus
Cordis
6.8
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Shinobi
Cordis
7.0
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Crosswire NT Terumo 7.7 Nitinol core, Hydrophilic

Non-Polymer Jacket

Manufacturer
Tip Load
Properties
Suoh 03
Asahi Intecc
0.3
Stainless Steel core, Hydrophilic
Manufacturer
Tip Load
Properties
SION blue
Asahi Intecc
0.5
Stainless steel core with hybrid coating
Manufacturer
Tip Load
Properties
SION (hydrophilic)
Asahi Intecc
0.7
Stainless Steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Runthrough NS tapered (0.008”)
Terumo
1.0
Duo Core, hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Samurai RC
Boston Scientific
1.2
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Cross-It 100XT (0.010”)
Abbott Vascular
1.7
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Gaia 1st (0.010”), 2nd (0.011”), and 3rd (0.012”)
Asahi Intec
1.7, 3.5, 4.5
Stainless steel core, hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Gaia Next 1 (0.011”), Gaia Next 2 (0.012”), Gaia Next 3 (0.012”)
Asahi Intec
2, 4, 6
Stainless steel core, hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Ultimate 3
Abbott Vascular
3
Stainless steel core, hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Miracle Bros 3, 6, 12
Asahi Intec
3, 6, 12
Stainless steel core, Hydrophobic
Manufacturer
Tip Load
Properties
Persuader 3 (-philic), 6 (-phobic)
Medtronic
5.1, 8.0
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
PROGRESS 40, 80, 120
Abbott Vascular
5.5, 9.7, 13.9
Durasteel core, Hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
ProVia 3 (-philic), 6 (-phobic)
Medtronic
8.3, 9.1
Stainless steel core, Hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Confianza 9 and 12 (-phobic)
Asahi Intecc
8.6, 12
Stainless steel core, Hydrophobic
Manufacturer
Tip Load
Properties
Persuader 9 (0.011”)
Medtronic
9.1
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
Persuader 9 (-phobic)
Medtronic
9.1
Stainless steel core
Manufacturer
Tip Load
Properties
Confianza Pro 9, 12 (0.009”)
Asahi Intecc
9.3, 12.4
Stainless steel core, Hydrophobic
Manufacturer
Tip Load
Properties
Hornet 10, 14 (0.008”)
Boston Scientific
10, 14
Stainless steel core, Hydrophilic
Manufacturer
Tip Load
Properties
ProVia 9, 12 (-phobic) (0.009”)
Medtronic
11.8, 13.5
Stainless steel core
Manufacturer
Tip Load
Properties
PROGRESS 140T, 200T (0.”, 0.009”)
Abbott Vascular
12.5, 13.3
Durasteel core, Hydrophilic, tapered tip
Manufacturer
Tip Load
Properties
Astato 20 (0.008”)
Asahi Intecc
20
Stainless steel core, tapered tip, hydrophilic and uncoated distal tip
Manufacturer
Tip Load
Properties
Astato XS 40 (0.014") Asahi Intecc 40 Stainless steel core, tapered tip, hydrophilic and uncoated distal tip

Externalization Wires

Manufacturer
Tip Load
Properties
RG3
Asahi Intecc
3.0
Stainless Steel core, distal hydrophobic with proximal hydrophilic coating
Manufacturer
Tip Load
Properties
R350 Teleflex 3.0 Nitinol core, hydrophilic coating

Wiggle Wire

Manufacturer
Tip Load
Properties
Wiggle Abbott Vascular 1.0 Stainless steel core, Hydrophilic

Extra Support Wires

Manufacturer
Tip Load
Properties
Grand Slam
Asahi Intecc
0.7
Stainless steel core, Hydrophobic
Manufacturer
Tip Load
Properties
Iron Man
Abbott Vascular
1.0
Stainless steel core, Hydrophobic
Manufacturer
Tip Load
Properties
Mailman Boston Scientific 0.8 Stainless steel core, Hydrophilic and uncoated distal tip

1. Strategies of CTO-PCI (Algorithm)

There is no single guidewire that can be universally used in all CTO lesions and all possible circumstances. Familiarity with various CTO guidewires, proper selection based on angiographic features, and proper wiring techniques are necessary for CTO PCI success.

CART = controlled antegrade and retrograde subintimal tracking; RWE = retrograde wire escalation 5-7

Wire Selection in CTO-PCI

Essential features to consider when selecting a guidewire include 1) tapered tip or not; 2) tip load and stiffness; 3) coated or non-coated polymer; 4) trackability.

1. Antegrade Approach

Although multiple guidewires can be used in the CTO intervention, the principle on how to choose the wire is mostly unchanged.

• For a focal lesion (<10–20 mm length), tapered, straight CTO without a side branch, the first choice is a soft, tapered, polymer-coated wire for initial (micro) channel tracking.
• However, it is essential to be aware that wire manipulation is often tricky, and linear force transmission can be attenuated.
• Antegrade wire escalation (AWE) is mostly recommended in the antegrade approach by penetration or drilling.
• When a wire passes the proximal cap of CTO, it is advisable to exchange the wire for a softer, steerable wire to minimize any inadvertent damage (expansion of subintimal space), called wire step down or escalation-deescalation.
• The parallel wiring method can be used under the antegrade approach. When the first wire fails to enter the true distal lumen, the second wire (tapered and stiffer wire) is advanced, while the first one can be used as a road map, thereby avoid entering into the subintimal space created by the first wire.

Our choice of wires for Antegrade Wire Escalation (AWE) (Stepwise approach) includes:

• Fielder (Non tapered polymer jacket tip), Fielder XT/XT-A/XT-R (Tapered polymer jacket tip)
• MiracleBros (Open Coil, Straight tip, high tip stiffness > facilitates drilling and can create a curve) or Gaia/Gaia Next series (Tapered, hydrophilic coating, composite core with 1:1 torque, high tip stiffness)
• Confianza 9/12 (Tapered, hydrophilic coating, high tip stiffness)

Wire for microchannel tracking:

• Fielder, Fielder XT, Fielder XT-A
• Gaia/Gaia Next series
• High Torque Pilot 50/150

Wire for Drilling:

• MiracleBros 6/12
• Confianza Pro 9, 12
• Pilot 200
• Progress 200T

If the vessel course is ambiguous:

• Pilot 200
• Confianza Pro
• Hornet 10, 14

Wire selection based on the location

Crossing the proximal cap:

• Fielder, Fielder XT/XT-A/XT-R (find microchannel)
• Gaia/Gaia Next series
• MiracleBros 3, 4.5, 6
• Confianza Pro

Appearance of CTO
First Choice
Second Choice
Third Choice
Tapered Stump
Fielder
Fielder XT
MiracleBros 6
Confianza Pro 9
Confianza Pro 12
Appearance of CTO
First Choice
Second Choice
Third Choice
Blunt Stump
MiracleBros 6
Confianza Pro 9
Confianza Pro 12
Progress 140
Progress 200
Appearance of CTO
First Choice
Second Choice
Third Choice
Functional CTO
Fielder
Fielder XT
MiracleBros 6
Confianza Pro 9
Confianza Pro 12
Appearance of CTO
First Choice
Second Choice
Third Choice
Bridging collaterals
Fielder
Fielder XT
Confianza Pro 9
Confianza Pro 12
Progress 200
Appearance of CTO
First Choice
Second Choice
Third Choice
Severe calcification MiracleBros 6 Progress 200 Confianza Pro 9
Confianza Pro 12

Choice of CTO wires based on angiographic features8

Navigating through the vessel:

• Gaia/Gaia Next series
• MiracleBros 4.5, 6
• Confianza Pro
• Ultimatebros 3
• Progress 140T, 200T

Distal entry into the lumen:

• Confianza Pro 12 (calcified distal cap)
• Progress 200T
• Hornet 14
• Astato 20, 40 (calcified distal cap)

2. Retrograde Approach

The operator’s ability to manipulate the wire is even more crucial in the retrograde or antegrade-retrograde CTO approach. Steering the guidewire through collateral channels to reach the CTO’s distal end and re-entering the other side of the true lumen is challenging for the operator. This category’s primary requirement is that the wire should be longer, with the lowest tip load and very low friction, hydrophilic/polymer jacket coating.

• For collateral crossings, the wire choice should be tapered tip polymer-coated wire (Fielder XT, Fielder XT-R) or non-tapered polymer-coated one (Sion Black, Fielder FC) or stainless steel composite core with shaping wire to tip (SUOH 03).
• CTO crossing can be done by many different strategies [direct retrograde crossing, controlled antegrade and retrograde subintimal tracking (CART), and reverse CART].
• The most frequently used retrograde wires are Gaia/Gaia Next series with microcatheter and MiracleBros 3.
• Confianza Pro 9 and Confianza Pro 12 are useful to cross a hard segment, while others could use Fielder XT and fighter as a retrograde ‘knuckle’ wiring to facilitate subintimal passage in a prolonged, calcified occlusion.

The following are the most used wires for a specific purpose:

Wires for collateral channels/Septal branches:

• Fielder, Fielder FC, Fielder XT-R (Asahi Intecc)
• Sion Black (Asahi Intecc)
• Suoh 03 (Asahi Intecc)

Wires for penetration:

• Gaia/Gaia Next (Asahi Intecc)/MiracleBros (Asahi Intecc)
• Confianza Pro (Asahi Intecc)

Wires for externalization:

• RG3 (Asahi Intecc)
• R350 (Teleflex)
• ViperWire Advance or Rotawire11

Guidewires for Atherectomy devices

There are two mechanical atherectomy devices available in the market, rotational atherectomy and orbital atherectomy.

Rotational Atherectomy

• Rotawire has entirely different physical properties compared to conventional guidewires. It is a thinner device with its 0.009-inch diameter (except for the more distal radio-opaque segment, which is 0.014 inches).10
• This wire’s most crucial requirement is to provide an excellent and stable support function for the rotating burr.
• It is made of homogeneous stainless steel to have a stable support function with decreased wire manipulative properties (flexibility and torquability).
• Two types of Rotawires are available
• Rotawire Drive Floppy (one with moderate support but better trackability)
• Rotawire Drive Extra Support (one with extra support but poorer trackability)

Orbital Atherectomy

Orbital atherectomy is performed over a 0.014” guidewire, in contrast to a 0.009” wire with rotational atherectomy.

• Viperwire is made of stainless steel to have a better support, silicone coating, and a radiopaque distal spring tip.
• Two Viperwires are available
• Viperwire Advance (stainless steel core: better support)
• Viperwire Advance with Flex Tip (Nitinol with stainless steel support coil) > better to navigate in complex anatomy.

Microcatheter and over-the-wire balloons are low profile and trackable systems with end-holes. It provides good wire support and allows precise wire control by preventing flexion, kinking, and prolapse of the guidewire, especially in complex coronary intervention. It is useful in navigating tortuous or angulated lesion, CTO lesion, complex bifurcation with or without acute angle side branch, and recrossing a jailed side branch. Hence, microcatheter and guidewire are used as a single unit (e.g., Fielder + FineCross) to navigate challenging anatomy in complex coronary intervention.

Are you interested in learning more about Hydrophilic guidewire? Contact us today to secure an expert consultation!

Types of microcatheter

1. Single lumen (based on size of catheter)

1. Standard (Corsair Pro, Tornus, Turnpike, Turnpike Spiral, Nhancer Pro X, Mizuki, Mamba, Teleport control, M-Cath)

2. Small (Caravel, Turnpike LP, FineCross, MicroCross 14, Mamba Flex, Teleport, Corsair XS

• Provide guidewire support in tortuous anatomy
• Facilitate guidewire placement and exchange

2. Dual lumen (Twin-Pass Torque & Twin-Pass, Sasuke, Crusade, FineDuo, NHancer Rx, ReCross)

• Useful for guidewire exchange in difficult wiring cases and acts like two microcatheters
• Provide support in tortuous anatomy
• Help to steer the wire through the side branch
• Facilitate to wire the bifurcation lesion
• Collateral access in CTO-PCI

3. Angulated (SuperCross, Venture, Swift Ninja)

• Facilitate in crossing the severely angulated side branch
• Provide great back up wire support

1. Simpson JB, Baim DS, Robert EW, et al. A new catheter system for coronary angioplasty. Am J Cardiol ;49:–22.
2. Colombo A, Mikhail GW, Michev I, et al. Treating chronic total occlusions using subintimal tracking and reentry: the STAR technique. Catheter Cardiovasc Interv ;64:407–11, discussion 412.
3. Galassi AR, Tomasello SD, Costanzo L, et al. Mini-STAR as bail-out strategy for percutaneous coronary intervention of chronic total occlusion. Catheter Cardiovasc Interv ;79:30 – 40.
4. Brilakis ES, Badhey N, Banerjee S. “Bilateral knuckle” technique and Stingray re-entry system for retrograde chronic total occlusion intervention. J Invasive Cardiol ;23:E37–9.
5. Brilakis ES, Grantham JA, Rinfret S, et al. A percutaneous treatment algorithm for crossing coronary chronic total occlusions. J Am Coll Cardiol Intv ;5:367–79.
6. Harding SA, Wu EB, Lo S, et al. A new algorithm for crossing chronic total occlusions from the Asia Pacific Chronic Total Occlusion Club. J Am Coll Cardiol Intv ;10:–43.
7. Galassi AR, Werner GS, Boukhris M, et al. Percutaneous recanalisation of chronic total occlusions: consensus document from the EuroCTO Club. EuroIntervention ;15:198–208.
8. Kini A, Sharma S, Narula J. Practical Manual of Interventional Cardiology, .
9. Pan M, Ojeda S, Villanueva E, et al. Structural Damage of Jailed Guidewire During the Treatment of Coronary Bifurcation Lesions: A Microscopic Randomized Trial. JACC Cardiovasc Interv. ;9(18):-. doi:10./j.jcin..06.030.
10. Barbato E, Colombo A, Heyndrickx GR. Interventional technology: rotational atherectomy. Percutaneous Interventional Cardiovascular Medicine: The EAPCI Textbook , vol II, 3–6, 195–211.
11. Joyal D, Thompson CA, Grantham JA, Buller CEH, Rinfret S. The retrograde technique for recanalization of chronic total occlusions: a step-by-step approach. J Am Coll Cardiol Intv ;5:1–11.