Parallel Stenting for Treatment of an In-stent Chronic Total Occlusion after Successful Dissection Reentry Technique

Abstract

Percutaneous coronary interventions (PCI) for chronic total occlusions (CTO) are the most challenging type of procedure in interventional cardiology and are traditionally associated with increased complexity and reduced procedural success rates. New techniques, such as retrograde approach and dissection reentry technique, offer alternatives in case of traditional antegrade wiring failure. In this paper, we present a successful implantation of a stent parallel to other existing stent in an in-stent CTO (IS-CTO) using dissection reentry technique. The technical details involved and the clues to successful outcome in an individual with in-stent CTO are discussed.

Coronary chronic total occlusions (CTOs) are defined as complete interruption of antegrade coronary flow of greater than 12 weeks duration and occurring in nearly 20% of all coronary angiograms. ¹ Percutaneous coronary interventions (PCI) for treatment of CTOs are technically demanding and are associated with lower success rates, compared with the conventional PCI procedures. Newer PCI techniques, such as retrograde approach and dissection reentry technique, may help us achieve success rates of greater than 90% in dedicated centers. ² In-stent chronic total occlusion (IS-CTO) is a specific lesion subset, which still represents a challenge and has traditionally been associated with suboptimal procedural success rates. A recent study showed that procedural success was high and similar in patients with IS-CTO, as compared with de novo CTO; however, IS-CTO was independently associated with major adverse cardiac events on follow-up. ³ We describe a case of successful implantation of stent parallel to other existing stent in an IS-CTO using sequential dissection reentry technique.

Case Report

A 67-year-old male with a history of hypertension, dyslipidemia, and coronary heart disease and background of previous PCI with one drug eluting stent (Taxus Liberte, Boston Scientific, Marlborough, MA) implantation in right coronary artery (RCA) before 12 years presented to our department complaining of worsening effort dyspnea. Stress myocardial perfusion imaging was performed, revealing inferior wall ischemia, and coronary angiography demonstrated IS-CTO of the dominant RCA with retrograde collateralization ( Fig. 1a ). Therefore, it was decided to perform a CTO PCI.

Fig. 1.

( a ) IS CTO (arrow) of the dominant RCA with retrograde collateralization, ( b ) a knuckle was performed on a Fielder XT guidewire, ( c ) successful implantation of a stent parallel to other existing stent (arrows) in IS-CTO using dissection reentry technique, and ( d ) final result in left anterior oblique projection. IS-CTO, in-stent chronic total occlusions; RCA, right coronary artery.

Percutaneous cardiac catheterization was performed using biradial access. An EBU 3.5 6Fr guide engaged the left coronary ostium and an AL1 7Fr guide the right coronary ostium. Antegrade wire escalation was our initial technique using support by a Caravel microcatheter (Asahi Intecc, Aichi, Japan). However, we failed with many wires (Fielder XT, Pilot 200, Gaia Second) to successfully re-canalize the lesion, because we were entering a dissection at the side of the old stent. Therefore, we changed our strategy according to the hybrid algorithm, and dissection/reentry technique was decided as our second approach. A knuckle was performed on a Fielder XT guidewire (Asahi Intecc, Aichi, Japan), and it was advanced into the subintimal space with the intention to reach the distal part of the vessel ( Fig. 1b ). Reentry was performed using the Limited Antegrade Subintimal Tracking (LAST) technique and a Gaia second guidewire (Asahi Intecc, Aichi, Japan). Lesion preparation was performed with multiple inflations of balloons with increased diameters, and the lesion was stented with an everolimus-eluting stent (Resolute Integrity, Medtronic), resulting in two stents lying parallel to each other ( Fig. 1c ). The intervention was successfully completed with a favorable angiographic result ( Fig. 1d ). The patient experienced an uneventful post-angiography course and was discharged on the following day free of symptoms. Postoperative follow-up was performed at 6 months. Coronary angiography showed that there was no restenosis inside the stent. The patient did not present any recurrent angina, and there was no myocardial ischemic event during 6 months of follow-up.

Discussion

Percutaneous coronary intervention of IS-CTOs remains a challenging procedure in interventional cardiology. The procedural success of IS-CTOs revascularization is high, and success rates continue to improve and lead to the latest studies at rates similar to de novo CTOs. ³ This has been achieved owing to the development of new CTO guidewires, advances in microcatheters, and development of new techniques. Percutaneous cardiac catheterization in such patients with IS-CTO is at high risk for complications, and it also has technical difficulties. Initiation of the procedure is often performed through bilateral femoral artery access. However, PCI for CTO is also feasible using radial access. ⁴ In our case, percutaneous cardiac catheterization was performed using biradial access, with a 7Fr antergrade and a 6Fr retrograde guide.

Initially, we applied an antegrade CTO recanalization technique with a single wire and a dedicated microcatheter. Indeed, antegrade techniques are cornerstone and are widely accepted as first-choice procedures. Although it could be considered that the existing stent can make visible the lumen of the vessel and facilitate wiring and tracking of the IS-CTO segment, the antegrade technique failed. This may be the result of high calcium content and challenging hard fibrous tissue of the IS-CTO, which makes wiring difficult.

The procedure we finally applied and resulted in successful revitalization was dissection and reentry technique. This technique is the evolutionary refinement of the subintimal tracking and reentry technique. ⁵ Although there are dedicated devices to perform a controlled dissection, like the Crossboss system (Boston Scientific) and facilitate the reentry, like the Stingray catheter (Boston Scientific), in many cases this can be also performed with knuckled (dissection) and stiff guidewires (reentry). Using this technique, even occluded segments in long lengths can be crossed safely and fast. In a recent study, Azzalini et al compared subadventitial stenting to controls recanalized using within-stent stenting for treatment of IS-CTO and showed favorable outcomes using dissection and reentry technique. ⁶

The Crossboss system is considered as extremely helpful in treating IS-CTO lesions. However, in our case, it was not utilized since a dissection at the side of the old stent was already performed with the guidewire, so we continued with the same knuckled guidewire, to reduce the cost of the procedure.

In our case, the stent was placed in parallel to the existing stent in a patient with IS-CTO. Because of the fibro-calcific morphology of the IS-CTO, true-to-true lumen crossing is difficult. The result showed that no worsening occurred in the patient after the operation, indicating that the parallel-stenting technique can be successful and safe. The combined application of the latest devices and the dissection reentry technique might provide an effective and safe approach for IS-CTO cases, where other techniques are not feasible.

The parallel stent placement in the subintimal space is an adaptation of the standard dissection/reentry technique for experienced CTO operators. Thus, more options are provided in cases that previously failed due to certain angiographic characteristics such as calcification and long CTO. This case describes how the dissection/reentry technique, with the advantage of the existing stent forming a clear open target, enabling rapid advancement of the wire into the distal true lumen. Once the wire engages the true lumen, the approach is standard dissection/reentry technique, with externalization of a long wire and PCI via the anterograde direction.

Intravascular imaging with intravascular ultrasound (IVUS) or optical coherence tomography (OCT) could be extremely helpful to understand better the anatomy of the lesion before stenting, as well as the final result, but they were not used due to limited availability at our laboratory at the time this procedure was performed.

The approach and intervention of coronary arteries with IS-CTO is an interesting procedure, which follows the same general rules with some technical details. This above-presented parallel stent placement technique could be used safely and effectively in the treatment of IS-CTO, especially for an IS-CTO with calcified morphology. Histopathological and anatomical characteristics of IS-CTO lesions should be taken into consideration to obtain the optimal benefit for the patient. However, a larger series of patients is required to support this technique.

Funding Statement

Funding Sources None.