Laocoön’s Revenge: A Novel Non-Drug Eluting Two-Stent Strategy for Complex Bifurcation Intervention

Note: Read CLD's accompanying interview with operator Gautam Kumar, MD, at Laocoön’s Revenge: A Novel Non-Drug Eluting Two-Stent Strategy for Complex Bifurcation Intervention — Talking With the Operator
 

Complex PCI in setting of high-bleeding risk (HBR) may bring the gift of symptom relief with the feared consequence of hemorrhagic complications. We present this case of complex PCI of a subacute/chronic total circumflex occlusion at a Medina 1,1,1 bifurcation using a novel “Laocoön strategy” — a two-stent technique utilizing non-DES systems (Tryton bifurcation stent, Tryton Medical, and a Cobra PzF nanocoated stent, CeloNova Biosciences).  

Case Report

A 57-year-old hypertensive man with recent admissions for severe lower gastrointestinal hemorrhages (due to diverticula) presented with recurrent chest discomfort and elevated cardiac biomarkers (troponin-I 4.2 ng/dL). At the time of his cardiac catheterization, his cardiac biomarkers were trending downwards and he no longer had resting chest discomfort. He was discovered to have a complete occlusion of the mid left circumflex (LCX) artery just proximal to a large, branching, third obtuse marginal branch (Figure 2A-B). We decided to give the patient a trial of DAPT (aspirin and clopidogrel) prior to PCI as he was no longer symptomatic and was currently undergoing gastroenterology evaluation.

He presented for PCI one month later. He still had exertional angina despite goal-directed medical therapy with two antianginals. There was mild hypokinesis of the inferolateral wall by echocardiography with preserved global left ventricular systolic function.  Using a 7 French EBU 3.75 Launcher guide catheter (Medtronic), we crossed the lesion with a Fielder XT wire (Asahi Intecc) assisted by a Caravel microcatheter (Asahi Intecc) (Figure 3). We then passed the microcatheter distally into the superior third obtuse marginal (OM3) branch and exchanged for a Choice PT Extra Support wire (Boston Scientific). After predilating the lesion with a 2.5 mm Chocolate balloon (TriReme Medical), we passed a Runthrough wire (Terumo) into the inferior OM3 branch. At this point, we prepared for PCI to a Medina 1,1,1 bifurcation lesion involving the large superior and inferior branches of the OM3 (Figure 4).      

To begin our bifurcation technique, we performed intravascular ultrasound (IVUS) demonstrating the reference diameter of the inferior branch to be 3.0 mm and the superior side branch to be 2.5 mm (Figures 5A-B). Given the patient’s high bleeding risk and need for a two-stent technique, we deployed a 2.5 x 3.5 x 19 mm Tryton bifurcation stent from the main branch into the superior OM3 side branch. During Tryton deployment, the second and third markers on the stent signify the transition zone with open struts to cover the main branch (Figure 5A-B).³ After proximal optimization technique (POT) of the deployed Tryton stent, we then rewired the inferior OM3 branch and deployed a 3.0 x 18 mm Cobra PzF stent from the main vessel into the inferior OM3 branch (Figure 6). We optimized our bifurcation stents by POT, a “kissing balloon inflation,” and final POT (Figure 7). Final angiography is demonstrated in Figure 8.

Four weeks after PCI, our patient had no recurrent episodes of melena or angina. He discontinued clopidogrel 30 days after PCI and underwent colonoscopy revealing severe left-sided diverticulosis with diverticula from the sigmoid to transverse colon. After this, he has continued aspirin monotherapy and has remained asymptomatic.

Discussion

Complex PCI in patients with HBR presents many challenges. We utilized a novel “Laocoön strategy” to treat a complex bifurcation lesion with a two-stent technique using non-DES systems (Tryton bifurcation stent and Cobra PzF nanocoated stent). To our knowledge, this is the first use of a non-DES with a Tryton bifurcation stent and the first non-DES bifurcation strategy for HBR patients.  

The Tryton bifurcation stent is currently approved by the U.S. Food and Drug Administration (FDA) for bifurcation stenting based on the Tryton confirmatory study, which showed noninferior target vessel revascularization and improved side branch diameter in patients with side branches ≥2.5 mm.⁴ The Tryton bifurcation stent is a bare metal platform with three zones: main branch, transition, and side branch. The main branch zone has minimal stent coverage to allow subsequent stent placement in the main vessel and the main branch. The transition zone has open struts which cover the ostium of the main branch and allow easy rewiring after deployment. The side branch zone is composed of a standard bare metal stent platform.³ The Tryton deployment technique simplifies a complex bifurcation stent technique requiring two stents due to its transition zone and differential diameter of the main branch and side branch zones.  

The Cobra PzF stent is coated with a nanocoated, drug-free, polyzene-F polymer that binds albumin, reduces platelet and complement activation, and promotes healthy endothelial cellular growth.⁵ However, due to the absence of an immunosuppressing mTOR inhibitor, the Cobra PzF drug-free stent re-endothelializes similarly to a bare metal stent. In its first trial, the PzF coated Catania stent demonstrated <4% clinically driven target vessel revascularization at 1 year.⁶ In the more contemporary, prospective, non-randomized SHEILD trial, the Cobra PzF stent achieved the pre-specified performance goals for both the primary endpoint of target vessel failure at 270 days as well as the powered secondary endpoint of angiographic in-stent late lumen loss.⁷ After 9-month clinical follow-up, there was infrequent (4.6%) clinically driven target lesion revascularization and an excellent safety profile with no stent thrombosis and ~1% myocardial infarction (MI) beyond the index periprocedural period. The Cobra PzF stent is currently FDA approved, requiring a minimum of 30 days of DAPT after deployment.

Our novel “Laocoön strategy” to treat complex bifurcation lesions with a non-DES two-stent technique may be applicable to other HBR patients. We present this case to further the discussion of optimal stent strategy in the growing HBR population. In Vergil’s epic, Laocoön was fated to be consumed by serpents. In the age of complex PCI, the Tryton bifurcation stent may overcome the Scylla and Charybdis of HBR by strangling the Cobra PzF nanocoated stent.

References

1. Giustino G, Chieffo A, Palmerini T, et al. Efficacy and safety of dual antiplatelet therapy after complex PCI. J Am Coll Cardiol. 2016; 68: 1851-1864.
2. Yeh RW, Kereiakes DJ, Steg PG, et al; DAPT Study Investigators. Lesion complexity and outcomes of extended dual antiplatelet therapy after percutaneous coronary intervention. J Am Coll Cardiol. 2017; 70: 2213-2223.
3. Généreux P, Kumsars I, Lesiak M, et al. A randomized trial of a dedicated bifurcation stent versus provisional stenting in the treatment of coronary bifurcation lesions. J Am Coll Cardiol. 2015; 65: 533-543.
4. Généreux P, Kumsars I, Schneider JE, et al. Dedicated bifurcation stent for the treatment of bifurcation lesions involving large side branches: outcomes from the Tryton Confirmatory Study. JACC Cardiovasc Interv. 2016; 9: 1338-1346.
5. La Manna A, Capodanno D, Cera M, et al. Optical coherence tomographic results at six-month follow-up evaluation of the CATANIA coronary stent system with nanothin Polyzene-F surface modification (from the Assessment of The LAtest Non-Thrombogenic Angioplasty Stent [ATLANTA] trial). Am J Cardiol. 2009; 103: 1551-1555.
6. Tamburino C, La Manna A, Di Salvo ME, et al. First-in-man 1-year clinical outcomes of the Catania Coronary Stent System with Nanothin Polyzene-F in de novo native coronary artery lesions: the ATLANTA (Assessment of The LAtest Non-Thrombogenic Angioplasty stent) trial. JACC Cardiovasc Interv. 2009; 2: 197-204.
7. Cutlip DE, Garratt KN, Novack V, et al; PzF SHIELD Trial Investigators. 9-Month clinical and angiographic outcomes of the COBRA Polyzene-F NanoCoated Coronary Stent System. JACC Cardiovasc Interv. 2017; 10: 160-167.

¹Wellstar Health System, Cardiovascular Medicine, Marietta, Georgia; ²Emory University School of Medicine, Division of Cardiology, Atlanta, Georgia; ³Atlanta VA Medical Center, Decatur, Georgia 

Author disclosures: The authors report no conflicts of interest regarding the content herein. No specific funding supported this work.

The authors can be contacted via Gautam Kumar, MD, at gautam.kumar@emory.edu.