CTO Corner

Innovation in CTO PCI: The Pace Accelerates

Chronic total occlusion PCI has grown during recent years in the United States for multiple reasons. First, the techniques have matured, providing reliably high success and low complication rates at experienced centers. Second, an extensive education campaign has been taking place, with multiple live courses and proctoring events. Third, after many years of inertia in equipment development, a wave in chronic total occlusion PCI device innovation is currently taking place, promising to further facilitate and increase success in these often complex procedures.

This CTO Corner column provides an overview of novel devices that have recently become available for use in the United States.

Guidewires

Guidewires remain one of the core tools for CTO PCI. Three new CTO guidewires recently became available: the RG3, Sion and Gaia (all Asahi Intecc) line of wires.

Emmanouil S. Brilakis

RG3 is a guidewire designed for externalization when the retrograde approach is being used (Figure 1). It is thin (0.010-inch diameter) and long (330-cm length) and half of its shaft is covered by a hydrophilic polymer. As a result, it advances easily through the microcatheter, much easier than previously used externalization wires such as the ViperWire Advance (Cardiovascular Systems, Inc.) and R350 (Vascular Solutions). Externalization is quicker and safer with the RG3; there is no need for flushing the microcatheter with Rotaglide and guide interaction is minimal. Thus, a step that could previously require 5 to 10 minutes can now be completed in less than a minute, making the retrograde approach safer and more efficient, hence more attractive to a broader range of interventionalists.

Overview of the RG3 guidewire.
Figure 1. Overview of the RG3 guidewire.

All images provided by Brilakis ES; reprinted with permission.

Sion (Figure 2) and Gaia (Figure 3) are “composite core” wires, which have a dual coil construction designed to enhance torquability, maneuverability and tip shape retention. Sion is a soft guidewire designed for collateral vessel crossing, both septal and epicardial. There are several cases in which a Fielder FC wire (the traditional “gold standard” for collateral crossing) would not cross, whereas the Sion did, although there are opposite examples as well. The Sion blue is a variation of the Sion with softer tip and more supportive body and is often used as a workhorse guidewire.

The Gaia wires represent the evolution of the Miracle and Confianza line of wires. The Gaia are stiff wires with tapered tips and high penetration power. Three types are available (Gaia First, Gaia Second and Gaia Third) with increasing tip stiffness. The distal 1-mm tip is pre-shaped to a 45-degree angle, and due to the composite core construction it has excellent shaping memory and retention. Although U.S. experience is still limited, these wires appear to be excellent for crossing long tortuous occlusions, but may require slower, more precise manipulation compared with previously used stiff guidewires.

 Overview of the Sion guidewire construction.
Figure 2. Overview of the Sion guidewire construction.

Microcatheters and Support Catheters

Corsair (Asahi Intecc) and FineCross MG (Terumo) have traditionally been the microcatheters of choice for CTO PCI. Two new microcatheters became available this year: the Turnpike (Vascular Solutions; Figure 4) and the MicroCross (Roxwood Medical). The Turnpike has a dual-layer bidirectional coil that facilitates with torque transmission and prevents kinking. It also has a soft, tapered tip to facilitate collateral branch crossing. The MicroCross is a 2.5F microcatheter with a distal tip marker.

Construction of the Gaia guidewires
Figure 3. Construction of the Gaia guidewires (Figures 1, 2, and 3 courtesy of Asahi Intecc).

Moreover, two support catheters are now available: the MultiCross (Roxwood Medical; Figure 5A) and the CenterCross (Roxwood Medical; Figure 5B). Both support catheters have a stabilizing self-expanding scaffold that is deployed proximal to the target lesion. The MultiCross contains three microcatheters within the scaffold, each located 120° apart. The CenterCross has a single, large central lumen that can accommodate a microcatheter. Both catheters require an adequate proximal landing zone in the target coronary vessel.

Device Innovation Continues

Device innovation can greatly improve the efficacy, efficiency and safety of CTO PCI, but can also be associated with challenges.

Features of the Turnpike microcatheter.
Figure 4. Features of the Turnpike microcatheter (courtesy of Vascular Solutions).

First, operators need to learn how to best use the new devices, how to select anatomic subsets most likely to benefit from their use and how to keep their use safe. This requires the operators to be open-minded and receptive to innovation, as well as to have the high procedural volume that is necessary for learning.

Second, new devices can add cost to the procedure, although some of the new devices, such as the Turnpike and MicroCross microcatheters are cheaper than currently utilized products. The added cost should be justified by the clinical benefit each device provides.

Overview of the MultiCross (Panel A) and CenterCross (Panel B) support catheters
Figure 5. Overview of the MultiCross (Panel A) and CenterCross (Panel B) support catheters (courtesy of Roxwood Medical).

Third, availability may be limited during the early stages of device release.

More and more CTO equipment is likely to become available during the next few years, promising to bridge the gap in outcomes between lower- and higher-volume CTO PCI volume centers. Taking the time and effort required to learn how the new devices work will likely pay great dividends in advancing contemporary CTO PCI practice.

Disclosure: Brilakis reports receiving honoraria/consultant fees from Abbott Vascular, Asahi, Boston Scientific, Elsevier, Janssen Pharmaceuticals, Sanofi, Somahlution, St. Jude Medical and Terumo; research support from Boston Scientific and Infraredx; and his spouse is an employee of Medtronic.

Chronic total occlusion PCI has grown during recent years in the United States for multiple reasons. First, the techniques have matured, providing reliably high success and low complication rates at experienced centers. Second, an extensive education campaign has been taking place, with multiple live courses and proctoring events. Third, after many years of inertia in equipment development, a wave in chronic total occlusion PCI device innovation is currently taking place, promising to further facilitate and increase success in these often complex procedures.

This CTO Corner column provides an overview of novel devices that have recently become available for use in the United States.

Guidewires

Guidewires remain one of the core tools for CTO PCI. Three new CTO guidewires recently became available: the RG3, Sion and Gaia (all Asahi Intecc) line of wires.

Emmanouil S. Brilakis

RG3 is a guidewire designed for externalization when the retrograde approach is being used (Figure 1). It is thin (0.010-inch diameter) and long (330-cm length) and half of its shaft is covered by a hydrophilic polymer. As a result, it advances easily through the microcatheter, much easier than previously used externalization wires such as the ViperWire Advance (Cardiovascular Systems, Inc.) and R350 (Vascular Solutions). Externalization is quicker and safer with the RG3; there is no need for flushing the microcatheter with Rotaglide and guide interaction is minimal. Thus, a step that could previously require 5 to 10 minutes can now be completed in less than a minute, making the retrograde approach safer and more efficient, hence more attractive to a broader range of interventionalists.

Overview of the RG3 guidewire.
Figure 1. Overview of the RG3 guidewire.

All images provided by Brilakis ES; reprinted with permission.

Sion (Figure 2) and Gaia (Figure 3) are “composite core” wires, which have a dual coil construction designed to enhance torquability, maneuverability and tip shape retention. Sion is a soft guidewire designed for collateral vessel crossing, both septal and epicardial. There are several cases in which a Fielder FC wire (the traditional “gold standard” for collateral crossing) would not cross, whereas the Sion did, although there are opposite examples as well. The Sion blue is a variation of the Sion with softer tip and more supportive body and is often used as a workhorse guidewire.

The Gaia wires represent the evolution of the Miracle and Confianza line of wires. The Gaia are stiff wires with tapered tips and high penetration power. Three types are available (Gaia First, Gaia Second and Gaia Third) with increasing tip stiffness. The distal 1-mm tip is pre-shaped to a 45-degree angle, and due to the composite core construction it has excellent shaping memory and retention. Although U.S. experience is still limited, these wires appear to be excellent for crossing long tortuous occlusions, but may require slower, more precise manipulation compared with previously used stiff guidewires.

 Overview of the Sion guidewire construction.
Figure 2. Overview of the Sion guidewire construction.

Microcatheters and Support Catheters

Corsair (Asahi Intecc) and FineCross MG (Terumo) have traditionally been the microcatheters of choice for CTO PCI. Two new microcatheters became available this year: the Turnpike (Vascular Solutions; Figure 4) and the MicroCross (Roxwood Medical). The Turnpike has a dual-layer bidirectional coil that facilitates with torque transmission and prevents kinking. It also has a soft, tapered tip to facilitate collateral branch crossing. The MicroCross is a 2.5F microcatheter with a distal tip marker.

Construction of the Gaia guidewires
Figure 3. Construction of the Gaia guidewires (Figures 1, 2, and 3 courtesy of Asahi Intecc).

Moreover, two support catheters are now available: the MultiCross (Roxwood Medical; Figure 5A) and the CenterCross (Roxwood Medical; Figure 5B). Both support catheters have a stabilizing self-expanding scaffold that is deployed proximal to the target lesion. The MultiCross contains three microcatheters within the scaffold, each located 120° apart. The CenterCross has a single, large central lumen that can accommodate a microcatheter. Both catheters require an adequate proximal landing zone in the target coronary vessel.

Device Innovation Continues

Device innovation can greatly improve the efficacy, efficiency and safety of CTO PCI, but can also be associated with challenges.

Features of the Turnpike microcatheter.
Figure 4. Features of the Turnpike microcatheter (courtesy of Vascular Solutions).

First, operators need to learn how to best use the new devices, how to select anatomic subsets most likely to benefit from their use and how to keep their use safe. This requires the operators to be open-minded and receptive to innovation, as well as to have the high procedural volume that is necessary for learning.

Second, new devices can add cost to the procedure, although some of the new devices, such as the Turnpike and MicroCross microcatheters are cheaper than currently utilized products. The added cost should be justified by the clinical benefit each device provides.

Overview of the MultiCross (Panel A) and CenterCross (Panel B) support catheters
Figure 5. Overview of the MultiCross (Panel A) and CenterCross (Panel B) support catheters (courtesy of Roxwood Medical).

Third, availability may be limited during the early stages of device release.

More and more CTO equipment is likely to become available during the next few years, promising to bridge the gap in outcomes between lower- and higher-volume CTO PCI volume centers. Taking the time and effort required to learn how the new devices work will likely pay great dividends in advancing contemporary CTO PCI practice.

Disclosure: Brilakis reports receiving honoraria/consultant fees from Abbott Vascular, Asahi, Boston Scientific, Elsevier, Janssen Pharmaceuticals, Sanofi, Somahlution, St. Jude Medical and Terumo; research support from Boston Scientific and Infraredx; and his spouse is an employee of Medtronic.