Healing responses after bifurcation stenting with the dedicated TRYTON side-branch stent™ in combination with XIENCE-V™ stents: A clinical, angiography, fractional flow reserve, and optical coherence tomography study: The PYTON (Prospective evaluation of the TRYTON side-branch stent™ with an additional XIENCE-v™ everolimus-eluting stent in coronary bifurcation lesions) study


  • Conflict of interest: There are no conflicts of interest to disclose related to this manuscript.

Correspondence to: Christophe Dubois, MD, PhD, Department of Cardiovascular Diseases, University Hospitals Leuven, Herestraat 49, B 3000 Leuven, Belgium. E-mail: christophe.dubois@uzleuven.be



We evaluated healing responses with optical coherence tomography (OCT), and clinical and angiographic outcome after bifurcation stenting with the TRYTON Side-Branch Stent™.


Dedicated bifurcation stents have been proposed as a potential alternative for treatment of true coronary bifurcation lesions.


We treated 20 consecutive patients with coronary bifurcation lesions and significant involvement of the side-branch (SB) with the TRYTON Stent and an additional XIENCE-V™ everolimus-eluting stent. At 9 months, we assessed the ratio of uncovered to total stent struts (RUTSS) with OCT, angiographic late luminal loss (LLL), and in-stent and in-segment restenosis. Clinical endpoints at 1 year included major adverse cardiac events (MACE) and their components [target lesion revascularization (TLR), myocardial infarction (MI), and cardiac death].


LLL (N = 16) was 0.34 (0.17–0.46), 0.29 (0.24–0.48) and 0.57 (0.29–0.73) mm in the proximal main vessel (MV), distal MV and SB, respectively. In-bifurcation binary in-stent restenosis occurred in four patients (25%), in-segment restenosis in five (31.25%). The RUTSS (N = 13) was 4.0 ± 5.8, 0.7 ± 1.3, 0, and 2.5 ± 3.6% in the proximal MV, distal MV, SB, and polygon of confluence, respectively. At 1 year, MACE occurred in 5 (25%) [4 TLR (20%), 3 MI (15%)].


The homogeneous stent strut coverage and the low LLL in the MV reflect proper healing characteristics of the TRYTON Stent in combination with the XIENCE-V™ stent. However, proximal MV edge and ostial SB restenoses together with overall clinical outcomes do not fulfill expectations of a dedicated bifurcation stent. © 2012 Wiley Periodicals, Inc.