Initial Experience With the Gaia Composite Core Guidewires in Coronary Chronic Total Occlusion Crossing

ABSTRACT: Inability to cross the occlusion with a guidewire is the most common cause of failure of coronary chronic total occlusion (CTO) interventions. We describe two cases of successful application of the novel Gaia family of coronary guidewires (Asahi Intecc) for crossing coronary CTOs using all available crossing strategies, namely antegrade wire escalation, antegrade dissection/reentry, and retrograde. 

J INVASIVE CARDIOL 2016;28(2):E22-E25 

KEY WORDS: new device, chronic total occlusion, guidewire 

The most common cause of coronary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) failure is inability to cross the occlusion with a guidewire.¹ In addition to skillful manipulation, appropriate guidewire selection is critical for procedural success; however, the development of novel CTO guidewires has been slow. The Gaia family of wires (Asahi Intecc) is a new generation of CTO guidewires recently introduced in the United States. These wires have a composite-core, dual-coil construction (Figure 1)^2,3 designed to enhance torquability, maneuverability, and ability to cross long tortuous occlusions, but require slower, more meticulous, and precise manipulation as compared with currently available guidewires. We report our initial experience with Gaia guidewires in CTO-PCI.

Case Report

Case #1. A 60-year-old man with hypertension, hyperlipidemia, ischemic cardiomyopathy (left ventricular ejection fraction, 25%), and atrial fibrillation presented with Canadian Cardiovascular Society (CCS) class II angina despite maximal medical therapy. He had coronary artery bypass (CABG) surgery 4 years prior to presentation with separate saphenous vein grafts (SVGs) to the first obtuse marginal artery, first diagonal artery, and right posterior descending artery (PDA). Diagnostic angiography demonstrated CTO of the left anterior descending (LAD) artery (Figure 2A), with patent SVGs to the PDA (Figure 2B) and obtuse marginal branch (Figure 2C), but occluded SVG to the diagonal. He was considered a poor candidate for re-do CABG due to a poor LAD target vessel, and was referred for CTO-PCI.

Bilateral femoral arterial access was obtained with 45 cm long, 8 Fr sheaths. The right coronary artery (RCA) was engaged with an AL 0.75 guide, and the left main with an XB 3.5 guide. Simultaneous dual injection demonstrated a long occlusion segment (Figure 2D). Antegrade wire escalation was attempted with Pilot 200 (Abbott Vascular) and Confianza Pro 12 (Asahi Intecc) guidewires through a Venture catheter (Vascular Solutions) (Figure 2E), but the wires could not be advanced through the occlusion. Subintimal crossing was subsequently achieved with a Gaia Second guidewire (Figure 2F), but due to severe calcification, we were unable to advance a microcatheter past the proximal occluded segment, despite multiple balloon dilations of the proximal cap with 1.25 mm and 1.5 mm balloons. A Sion wire (Asahi Intecc) was then used for retrograde crossing from the PDA through a septal perforator into the mid LAD, followed by delivery of a Corsair microcatheter (Asahi Intecc) (Figure 2G). However, we could not advance a guidewire (Pilot 200 or Confianza Pro 12) into the proximal LAD. The proximal LAD was modified with a 0.9 mm coronary laser catheter (Spectranetics) at maximum fluency and energy, enabling balloon crossing and lesion predilation. A 6 Fr GuideLiner catheter (Vascular Solutions) was advanced to the mid LAD, followed by successful retrograde crossing using the GuideLiner reverse-controlled antegrade and retrograde tracking (GuideLiner reverse CART) technique: a 2.5 x 20 mm balloon was inflated to 20 atm antegradely, followed by retrograde crossing with the Gaia Third guidewire (Figure 2H). The LAD was successfully stented with multiple drug-eluting stents (Figure 2I). The patient’s hospital course was uncomplicated and he experienced complete angina resolution.

Case #2. A 69-year-old man with a prior history of hypertension, hyperlipidemia, nicotine dependence, and coronary artery disease presented with CCS class III angina on maximal medical therapy and adequate rate-pressure product control. He had undergone stenting of the LAD 7 years prior to presentation. Coronary angiogram demonstrated an RCACTO (Figure 3A) with a patent LAD stent.

Bilateral femoral arterial access was obtained with 45 cm-long, 8 Fr sheaths. The RCA was engaged with an AL 0.75 guide and the left main with an XB 3.5 guide. Given a tapered proximal cap and short lesion length with an angiographically visible microchannel (Figure 3A), a primary antegrade approach was pursued. An initial attempt at antegrade crossing using Fielder-XT (Asahi Intecc) and Pilot 200 guidewires was unsuccessful (Figure 3B). A brief attempt at retrograde crossing through septal perforators with a Sion guidewire also failed. A repeat antegrade crossing attempt with a Pilot 200 guidewire resulted in subintimal crossing. Dedicated reentry equipment (Stingray balloon and guidewire [Boston Scientific]) was unavailable, and wire-based reentry attempts with Pilot 200, Fielder XT, and Confianza Pro 12 guidewires were unsuccessful. A Gaia Third guidewire was successfully used for true lumen reentry, as confirmed by contralateral injection (Figure 3C). The RCA was stented with three drug-eluting stents with an excellent final angiographic result (Figure 3D). The patient had an uneventful recovery with complete resolution of angina.

DISCUSSION

Our cases demonstrate how use of novel composite-core, dual-coil guidewires can facilitate CTO-PCI. Inability to cross the occlusion with a guidewire remains the main reason for CTO PCI failure.¹ Three crossing strategies are currently being utilized for CTO crossing: antegrade wire escalation, antegrade dissection/reentry, and retrograde, each with unique advantages and disadvantages.⁴ Rapid change between crossing strategies is recommended to increase efficiency if no progress is achieved with the initial approach.⁵ Specially designed CTO guidewires are critical for all CTO crossing strategies. Many expert operators currently recommend using a limited selection of guidewires, such as Fielder XT, Confianza Pro 12, and Pilot 200.^4,5 A longterm latency in guidewire development recently ended with the introduction of composite-core, dual-coil guidewires, such as the Gaia guidewires (Figure 1).

The Gaia guidewires have stiff, tapered tips with several innovations as compared with traditional CTO guidewires. The tip is a micro-cone tapered tip for smooth lesion entry. The tip core is round instead of being flat, and has a composite core consisting of stainless-steel tube-rope coil with traditional spring coil on the outside (composite-core, dual-coil construction, as shown in Figure 1B). The distal coil consists of six instead of one wire and has ten times more torque force, enabling excellent 1:1 torque transmission to avoid torque “whip.” The distal 1 mm tip is preshaped to a 45° angle and has excellent shape memory and retention. The modification in core thickness allows the wire tip to deflect away from hard tissue, such as calcium and subintimal layers, for better intimal tracking (Figure 1C). The Gaia wires are available in three types (Gaia First, Gaia Second, and Gaia Third), with increasing tip stiffness and tapered tip diameter (Figure 1C). These novel guidewires have been available in Japan since 2012, in Europe since 2013, and in the United States since 2014.

Our cases demonstrate successful use of the Gaia guidewires with all CTO crossing strategies. Antegrade wire escalation remains the most commonly used strategy for crossing coronary CTOs due to simplicity, widespread equipment availability, and potentially lower risk compared with more complex strategies.^4,6-10 Antegrade wire escalation most commonly starts with a polymer-jacketed, tapered-tip soft guidewire, such as the Fielder XT, followed by a polymer-jacketed stiff guidewire, such as the Pilot 200 (preferred if the vessel course is ambiguous) or a stiff, non-jacketed tapered-tip guidewire, such as the Confianza Pro 12 guidewire (preferred if the occlusion path is clear).⁵ For long occlusions (>20 mm), use of upfront dissection/reentry is currently favored in the “hybrid” CTO crossing algorithm because maintaining true lumen position with guidewires can be challenging, time consuming, and associated with lower success rate. As illustrated in case #1, a very long CTO was crossed with a Gaia Second guidewire, suggesting that the Gaia wires may enhance the likelihood of antegrade guidewire crossing success even in long, complex occlusions.

Commonly used guidewires in the retrograde approach include the Sion guidewire (for crossing the collateral) as well as the Pilot 200 and Confianza Pro 12 guidewires (for crossing the occlusion). The most common technique for retrograde crossing is the reverse CART.^11,12 Excellent retrograde guidewire tracking is important for successful reverse CART. As illustrated in case #1, the Gaia Third guidewire enabled successful entry into the antegrade GuideLiner¹³ after other guidewires had failed.

Crossing back into the distal true lumen after subintimal antegrade guidewire crossing can be challenging, and is usually facilitated by use of the Stingray balloon and guidewire.¹⁴ A Stingray system was not available for use during case #2, yet the use of a Gaia Third guidewire enabled successful reentry due to its excellent torque response and stiff, tapered tip.

Although our initial experience with the Gaia guidewires was very promising, there are some important limitations. First, due to limited availability, we mainly used the Gaia Third guidewire, although the Gaia Second is the most commonly used Gaia guidewire in Japan; determining which Gaia type is optimal for certain lesion characteristics will require additional investigation and experience. Second, many more cases are needed to establish the overall efficacy and safety of the wires. Third, manipulation of the guidewire is different (much slower) than traditional guidewire handling to allow time for torque transmission to the tip and to navigate through tortuous vessels. Once the tip is deflected, it is withdrawn slightly and the wire direction is changed to avoid subintimal entry. Tactile feedback is extremely important for such manipulations and requires experience. Fourth, whether similar results can be replicated in less experienced CTO-PCI centers remains to be determined.

CONCLUSION

In summary, the novel Gaia guidewires appear highly promising for enhancing our ability to successfully cross CTOs during all available CTO crossing strategies.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Vo reports honoraria from Boston Scientific. Dr Brilakis reports consulting/speaker honoraria from Abbott Vascular, Asahi Intecc, Boston Scientific, Elsevier, Somahlution, St. Jude Medical, and Terumo Corporation; research support from Boston Scientific and InfraRedx; spouse is employee of Medtronic. The remaining author reports no disclosures regarding the content herein. 

Manuscript submitted April 28, 2015, final version accepted May 5, 2015. 

Address for correspondence: Emmanouil S. Brilakis, MD, PhD, VA North Texas Health Care System, The University of Texas Southwestern Medical Center at Dallas, Division of Cardiology (111A), 4500 S. Lancaster Rd, Dallas, TX 75216. Email: esbrilakis@gmail.com

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