Segmental comparison between a dedicated bifurcation stent and balloon angioplasty using intravascular ultrasound and three-dimensional quantitative coronary angiography: A subgroup analysis of the Tryton IDE randomized trial.

OBJECTIVE: Randomized comparison between the Tryton Side Branch Stent (Tryton Medical, Durham, NC), used in combination with a main branch drug-eluting stent (DES), and side branch balloon angioplasty (SBBA, in combination with a main branch DES) using intravascular ultrasound (IVUS), and three-dimensional quantitative coronary angiography (3D-QCA). BACKGROUND: The Tryton stent has been developed to improve clinical outcomes after percutaneous coronary intervention (PCI) of bifurcation lesions. METHODS: We present the pre-specified IVUS (n = 159) and 3D-QCA (n = 190) sub-group analyses of the Tryton coronary bifurcation trial (randomizing Tryton vs. SBBA). RESULTS: There were no differences in the main branch with regard to minimal lumen area (MLA) (5.33 ± 1.37 in Tryton vs. 5.69 ± 1.72 mm2 in SBBA, P = 0.235) with low neo-intima area in both groups. In the side branch, there were also no statistical significant differences between both groups (3.04 ± 1.02 in Tryton vs. 3.46 ± 1.15 mm2 in SBBA, P = 0.072). On 3D-QCA, no differences in minimal lumen diameter (MLD) and percentage diameter stenosis (%DS) were observed in the proximal and distal main branches. In the side branch, there were also no differences found in %DS and MLD (MLD: 1.34 ± 0.043 mm [Tryton] vs. 1.45 ± 0.31 mm [SBBA], P = 0.090). CONCLUSIONS: There were no differences in 9-month luminal dimensions of the side branch between the Tryton Stent and Side Branch Balloon Angioplasty, as assessed with IVUS (MLA) and 3D QCA (MLD). Angiographic and ultrasound results of the main branch were not negatively influenced by the Tryton stent. © 2016 Wiley Periodicals, Inc.

Outcomes of a dedicated stent in coronary bifurcations with large side branches: A subanalysis of the randomized TRYTON bifurcation study.

OBJECTIVES: To examine the benefit of the Tryton dedicated side branch (SB) stent compared with provisional stenting in the treatment of complex bifurcation lesions involving large SBs. BACKGROUND: The TRYTON Trial was designed to evaluate the utility of a dedicated SB stent to treat true bifurcation lesions involving large (≥2.5 mm by visual estimation) SBs. Patient enrolled in the trial had smaller SB diameters than intended (59% SB ≤2.25 mm by Core Lab QCA). The TRYTON Trial did not meet its primary endpoint due to an increased rate of peri-procedural myocardial infarctions (MIs). METHODS: The TRYTON Trial randomized 704 patients to the Tryton SB stent with main vessel DES versus provisional SB treatment with main vessel DES. The rates of the primary end point of target vessel failure and the secondary powered end point of angiographic percent diameter stenosis in the SB at 9 months were assessed and compared between the two treatment strategies among patients with a SB ≥2.25 mm diameter at baseline determined by Core Lab QCA. RESULTS: Among the 704 patients enrolled in the TRYTON Trial, 289 patients (143 provisional and 146 Tryton stent; 41% of entire cohort) had a SB ≥2.25 mm. The primary end point of TVF was numerically lower in the Tryton group compared with the provisional group (11.3% vs. 15.6%, P = 0.38), and was within the non-inferiority margin. No difference among the rates of clinically driven target vessel revascularization (3.5% vs. 4.3% P = 0.77) or cardiac death (0% both groups) were seen. In-segment percent diameter stenosis of the SB was significantly lower in the Tryton group compared with the provisional group (30.4% vs. 40.6%, P = 0.004). CONCLUSIONS: Analysis of the TRYTON Trial cohort of SB ≥2.25 mm supports the safety and efficacy of the Tryton SB stent compared with a provisional stenting strategy in the treatment of bifurcation lesions involving large SBs. © 2015 Wiley Periodicals, Inc.

Dedicated Bifurcation Stent for the Treatment of Bifurcation Lesions Involving Large Side Branches: Outcomes From the Tryton Confirmatory Study.

OBJECTIVES: The aim of this study was to prospectively study and confirm the safety and efficacy of the Tryton Side Branch Stent in the treatment of coronary artery bifurcations involving large side branches (SBs). BACKGROUND: The TRYTON Pivotal randomized controlled trial (RCT) was designed to compare the Tryton stent with standard provisional SB stenting in large vessels. The trial inadvertently enrolled patients with too small SBs (<2.25 mm). The overall trial did not meet its primary endpoint, because of an increased rate of periprocedural myocardial infarction in the Tryton stent arm. A post hoc analysis restricted to the intended population showed that the trial would have met its endpoint if only patients with SBs ≥2.25 mm in diameter (by core laboratory quantitative coronary angiography) had been enrolled. METHODS: The Tryton Confirmatory Study was a prospective, single-arm extension of the TRYTON Pivotal RCT that enrolled an additional 133 patients treated with the Tryton Side Branch Stent. It was designed to confirm the results of the post hoc analysis and emphasized the inclusion of appropriately sized SBs. The primary endpoint was noninferiority with regard to periprocedural myocardial infarction (creatine kinase myocardial band 3 times the upper limit of normal) compared with a performance goal based on the TRYTON Pivotal RCT. RESULTS: Among the 133 enrolled patients, 132 (99.2%) had SBs ≥2.25 mm. Baseline clinical and angiographic parameters were similar in this study and the RCT. Periprocedural myocardial infarction occurred in 10.5% of patients, which was numerically lower than the provisional group in the TRYTON Pivotal RCT (11.9%). The 95% confidence bounds did not extend beyond the pre-defined performance goal of 17.9%, meeting the noninferiority primary endpoint. CONCLUSIONS: The Tryton Confirmatory Study, in conjunction with the post hoc analysis of the intended population in the TRYTON Pivotal RCT, supports the safety and efficacy of the Tryton Side Branch Stent for treatment of bifurcation lesions involving large SBs.

A randomized trial of a dedicated bifurcation stent versus provisional stenting in the treatment of coronary bifurcation lesions.

BACKGROUND: Bifurcation lesions are frequent among patients with symptomatic coronary disease treated by percutaneous coronary intervention. Current evidence recommends a conservative (provisional) approach when treating the side branch (SB). OBJECTIVES: The TRYTON (Prospective, Single Blind, Randomized Controlled Study to Evaluate the Safety & Effectiveness of the Tryton Side Branch Stent Used With DES in Treatment of de Novo Bifurcation Lesions in the Main Branch & Side Branch in Native Coronaries) bifurcation trial sought to compare treatment of de novo true bifurcation lesions using a dedicated bifurcation stent or SB balloon angioplasty. METHODS: We randomly assigned patients with true bifurcation lesions to a main vessel stent plus provisional stenting or the bifurcation stent. The primary endpoint (powered for noninferiority) was target vessel failure (TVF) (cardiac death, target vessel myocardial infarction, and target vessel revascularization). The secondary angiographic endpoint (powered for superiority) was in-segment percent diameter stenosis of the SB at 9 months. RESULTS: We randomized 704 patients with bifurcation coronary lesions at 58 centers (30 from Europe and 28 from the United States). At 9 months, TVF was 17.4% in the bifurcation stent group compared with 12.8% in the provisional group (p=0.11), mainly because of a higher periprocedural myocardial infarction rate (13.6% vs. 10.1%, p=0.19). The TVF difference of +4.6% (2-sided 95% confidence interval: -1.0 to 10.3; upper limit of the 1-sided 95% confidence interval: 10.3) was not within the pre-specified noninferiority margin of 5.5% (p=0.42 for noninferiority). The SB in-segment diameter stenosis among the angiographic cohort was lower in the bifurcation stent group compared with the provisional group (31.6% vs. 38.6%, p=0.002 for superiority), with no difference in binary restenosis rates (diameter stenosis≥50%) at 9 months follow-up (22.6% vs. 26.8%, p=0.44). CONCLUSIONS: Provisional stenting should remain the preferred strategy for treatment of non-left main true coronary bifurcation lesions. (Prospective, Single Blind, Randomized Controlled Study to Evaluate the Safety & Effectiveness of the Tryton Side Branch Stent Used With DES in Treatment of de Novo Bifurcation Lesions in the Main Branch & Side Branch in Native Coronaries [TRYTON]; NCT01258972).