Complex Case Interventions

“Bilateral Knuckle” Technique and Stingray Re-Entry System for Retrograde Chronic Total Occlusion Intervention

Emmanouil S. Brilakis, MD, PhD, Neeraj Badhey, MD, Subhash Banerjee, MD
Emmanouil S. Brilakis, MD, PhD, Neeraj Badhey, MD, Subhash Banerjee, MD
ABSTRACT: We report a novel technique for retrograde chronic total occlusion intervention, in which the lesion is crossed by forming and advancing a “knuckle “in both the antegrade and retrograde guidewire, followed by reentry in the true lumen by using the Stingray re-entry system.
Key words: percutaneous coronary intervention; chronic total occlusion; stents

Editor’s Note: “This illustrative case describes a successful recanalization of a complex CTO case using various techniques and the use of a novel balloon catheter which can allow passage of the guidewire in the side. Clearly care should be taken not to inflate a subintimal balloon at very high pressures. Also advancement of the guidewires should be constantly watched by contralateral injections." — Samin K. Sharma, MD, Mount Sinai Medical Center, New York, New York

Several techniques have been described for crossing a chronic total occlusion (CTO) using retrograde techniques, such as the just marker technique, the retrograde true lumen puncture, the Controlled Antegrade and Retrograde Tracking and dissection (CART) and reverse CART technique.1 We report a novel technique that involves formation of a knuckle in both the antegrade and retrograde guidewire, followed by use of the Stingray system (Bridgepoint Medical, Minneapolis, Minnesota) for re-entry into the true distal lumen.

Case Report. A 79-year-old male presented with severe chronic angina and congestive heart failure. Diagnostic coronary angiography demonstrated a focal lesion in the mid left anterior descending artery and CTO of a large obtuse marginal branch (OM) and the proximal right coronary artery. The patient was considered a poor surgical candidate and was referred for percutaneous coronary intervention.

The left main coronary artery was engaged with a 7 French (Fr) XB 3.5 guide and anticoagulation was achieved with unfractionated heparin. The left anterior descending artery was successfully stented with a 3.0 x 28 mm sirolimus-eluting stent. We subsequently attempted to intervene on the OM CTO (Figure 1A). Due to the lack of a stump, we proceeded with a primary retrograde approach through an epicardial collateral from the first diagonal branch to the OM. The collateral branch was wired without difficulty using a Fielder FC wire (Abbott Vascular, Santa Clara, California) through a 150 cm Finecross catheter (Terumo Medical, Somerset, New Jersey) (Figure 1B). We attempted to retrogradely cross the lesion with the Fielder FC wire, a Pilot 200 and a Confianza Pro 12 wire (Abbott Vascular), but were not successful. We were also unable to cross the CTO antegradely using a Whisper, Pilot 200, and Confianza Pro 12 wire. We formed a “knuckle” on a Pilot 200 retrograde guidewire (Abbott Vascular) (Figure 1C) that was advanced subintimally across the lesion. We delivered a 2.5 x 12 mm balloon retrogradely and attempted CART, and then delivered a 2.5 x 12 mm balloon antegradely and attempted reverse CART, both without success.

We then formed a knuckle on a Pilot 200 antegrade guidewire and were able to advance it parallel to the retrograde guidewire across the CTO. A Stingray balloon (Bridgepoint Medical) was inserted antegradely over the knuckle wire. After inflation of the Stingray balloon at 2 atm, true lumen reentry was successfully achieved using a Stingray guidewire (Figure 1E). After implantation of three everolimus-eluting stents, antegrade flow in the second obtuse marginal branch was restored (Figure 1F). The patient had an uneventful recovery and marked angina improvement.

Discussion. One of the main challenges of this case was the lack of a stump and the presence of a large side branch at the CTO occlusion area; this challenge was overcome by using a bilateral (antegrade and retrograde) “knuckle” wire technique. Moreover, use of the Stingray balloon and wire system facilitated crossing of the antegrade guidewire into the distal true lumen.

Retrograde delivery of a guidewire is a powerful predictor of successful completion of CTO interventions.2 However, the retrograde guidewire can cross into the proximal true lumen in only a few cases,3 necessitating use of different techniques for crossing. The CART technique consists of inflation of a balloon in the subintimal space over the retrograde guidewire, which creates a space for entry of the antegrade guidewire.4 In the reverse CART technique an antegrade balloon is inflated in the subintimal space followed by retrograde wire crossing. Reverse CART has become the most commonly currently utilized retrograde crossing technique.5 However, both CART and reverse CART were unsuccessful in our patient.

The “knuckle” wire technique consists of bending the tip of a wire into a loop that is then advanced through the subintimal space crossing an occlusion.6 This technique is usually performed during antegrade crossing attempts, especially in long CTO lesions. Several subtypes have been described, such as the subintimal tracking and re-entry (STAR)7 and limited antegrade subadventitial tracking (LAST)8 techniques. In STAR the knuckle is advanced distally in the target vessel until it re-enters the target vessel, whereas in LAST reentry is performed more proximally in the vessel to minimize the length of subintimal stenting with resultant side branch loss. In our case we formed a “knuckle” with both the antegrade and retrograde guidewire: the retrograde guidewire “knuckle” allowed it to track the vessel tortuosity instead of perforating through. Once a retrograde subintimal pathway had been created, an antegrade wire “knuckle” could be advanced through the CTO region. To the best of our knowledge, this is the first report of “bilateral knuckle” technique for retrograde CTO PCI.

Re-entry after subintimal passage can be achieved by several mechanisms, such as use of hydrophilic and tapered tip wires, using the TwinPass catheter (Vascular Solutions, Minneapolis, Minnesota), or the Venture catheter (St. Jude Medical, St. Paul, Minnesota).6 Another option is use of the Stingray CTO re-entry system (Bridgepoint Medical, Minneapolis, Minnesota) (Figure 2),9 which consists of two components: the Stingray CTO orienting balloon catheter and the Stingray CTO re-entry guidewire. The Stingray balloon has a flat shape with two side exit ports: upon low-pressure (2–4 atm) inflation it orients one exit port automatically towards the vessel true lumen. The Stingray guidewire is a stiff guidewire with a 20 cm distal radiopaque segment and a 0.0035-inch distal taper. The Stingray guidewire can be directed towards one of the two side ports of the Stingray balloon to re-enter the distal true lumen, as in our case (Figure 1E). To the best of our knowledge this is the first use of the Stingray system for true lumen re-entry in retrograde CTO intervention.

The “bilateral knuckle” technique has limitations. If the knuckle loop is too large it can cause significant enlargement of the subintimal space, potentially compressing the true lumen and making re-entry efforts challenging. Antegrade contrast injections should be avoided to minimize the risk for subintimal contrast entry and stain. Hydrophilic guidewires may be best suited for knuckle creation. The knuckle should be ideally advanced past areas of tortuosity in a horizontal segment of the target vessel, where use of the Stingray system offers the best chance for re-entry. After crossing into the true lumen, the Stingray guidewire should be advanced for only a short distance, as its stiff tapered tip could cause injury of the target vessel.

In summary, the “bilateral knuckle” technique and the Stingray re-entry system may be useful additions to the retrograde CTO interventions armamentarium.

Acknowledgment. We gratefully acknowledge the tremendous support of the cardiac catheterization laboratory team at the Dallas VA Medical Center for enabling the development of novel catheterization techniques and the performance of clinical research.


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From the VA North Texas Healthcare System and University of Texas Southwestern Medical Center at Dallas, Dallas, Texas. Disclosures: Dr. Brilakis reports speaker honoraria from St. Jude Medical and Terumo; research support from Abbott Vascular and InfraReDx; and salary from Medtronic (spouse). Dr. Banerjee reports speaker honoraria from St. Jude Medical, Medtronic, and Johnson & Johnson and research support from Boston Scientific and The Medicines Company. Dr. Badhey has nothing to report. 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.