1. The Tryton Bifurcation Trial:
A randomized comparison of a provisional one-stent vs. a dedicated two-stent strategy for true bifurcation coronary lesions
Martin B. Leon, MD
for the Tryton Bifurcation Trial Investigators
Columbia University Medical Center
Cardiovascular Research Foundation
New York City
Wednesday, October 30, 2013

2. Disclosure Statement of Financial Interest TCT 25: San Francisco, CA; Oct 27 - Nov 1, Martin B. Leon, MD
Within the past 12 months, I or my spouse/partner have had a financial interest/arrangement or affiliation with the organization(s) listed below.
Affiliation/Financial Relationship
Company
Research Support (CUMC)
Consulting Fees/Honoraria
Major Stock Shareholder/Equity
Abbott, Boston Scientific, Medtronic
None

3. Tryton Side Branch Stent
8 mm
4.5 mm
6.5 mm
Main Branch Zone
Transition Zone
Side Branch Zone
Tryton is a Cobalt alloy bare metal stent

4. Tryton Study Design
Baseline Angiography – Eligible for Randomization   
Tryton side branch + DES (main vessel)
DES (main vessel) + Provisional side branch
N = 704  
TVF Primary Endpoint
Clinical F/U at 9 months
Clinical F/U at 9 months  
Angiographic F/U at 9 months
% DS side branch n~374
Angiographic F/U at 9 months  
IVUS F/U at 9 months
IVUS Cohort n~96
IVUS F/U at 9 months

5. Primary and Secondary Endpoints
Study design: Intention-to-treat (ITT) is primary analysis cohort, 1:1 randomization
Primary Endpoint: Target vessel failure @ 9 months follow-up (all patients): non-inferiority
cardiac death
target vessel MI (peri-procedural > 3X CK-MB)
target vessel revascularization (ischemia-driven, main vessel or side branch)
Secondary Endpoint: % diameter stenosis (in-segment) of side branch at 9 months follow-up (angiographic cohort only): superiority

6. Medina Classification (Core Lab)
“True”
Bifurcation
T: 89.9%
P: 86.2%
T:49.2%
P:42.1%
T:15.8%
P:16.0%
T: 24.9%
P: 28.1%
T: 1.4%
P: 2.6%
T: 2.3%
P: 4.9%
T: 2.8%
P: 4.0%
T: 3.4%
P:2.3%
Table 8a Core Lab run date 5 Sept 2013 FULL Cohort
P = Provisional
T = Tryton

7. Additional Side Branch Stents (Site Reported)
Provisional (n= 349)
28 (8.0%)
Tryton (n= 355)
3 (0.9%)
7 (2.0%)
Tryton Prox at lesion (3/0.9%) Distal (7/2.0%)
Provisional: Prox/at lesion (23/6.6%), Distal (6/1.7%)
At target (Proximal Distal)
Additional Stent Table

8. Target Vessel Failure (TVF)* Primary Endpoint%
Provisional
Tryton
P=0.108
Verified DF, Table B1 Run Date 30 Sep 2013, p 4 of 131, Tables and Figures from HCRI 14-Oct-13
* TVF = Cardiac death, TV–MI and TVR

9. Target Vessel Failure (TVF) Primary Endpoint%
P= 0.108
Provisional
Tryton
P = 0.109
P =0.564
Verified DF, Table B1 Run 30 Sept 2013, page 4 of 131, Tables and Figures from HCRI 14-Oct-2013
Non Hierarchical

10. Side Branch %DS (In-segment) Secondary Endpoint
Provisional
Tryton
P=0.002
Verified DF, Table 1 Run Date 30 Sept 2013, page 3 of 131, Tables and Figures from HCRI 14-Oct-13
Secondary Superiority Endpoint Met

11. Target Vessel Failure (TVF) Side Branch ≥ 2.25 mm%
P= 0.383
Provisional
Tryton
P = 0.563
P =0.769
LARGE VESSEL Table B1.b req20 Tb1.B2 Hierarchical TVF RVD 225 b Run Date 15 Oct 2013 proofed lll
Non Hierarchical

12. Angiographic Outcomes (QCA) Side Branch ≥ 2.25 mm%
Provisional
Tryton
P = 0.004
P = 0.260
Binary Restenosis: Table 14b Run date 15 Oct 2013 entered df verified lll
%Diameter Stenosis: Table 1b. Primary Endpoint SB RVD >= Oct 13 entered df verified lll
Provisional (N=81)
Tryton (N=63)

13. Conclusions
The Tryton two-stent strategy in true bifurcations (88%) compared with the provisional strategy (8.0% side branch stents) did not meet the non-inferiority clinical endpoint (TVF), due to a relatively higher frequency of small peri-procedural CK-MB elevations.
However, both strategies were safe (rare clinically significant MIs and stent thrombosis) and both had low 9-month clinically-driven TVR (P:3.6%,T:4.7%).
DES in the main vessel performed well in both arms.
Tryton improved side branch % diameter stenosis at FU (secondary endpoint; P=0.002)

14. Conclusions Post-hoc subset analyses indicated:
A striking disparity between binary restenosis and clinically-driven TVR for both arms, indicating that side branch angiographic restenosis is uncommonly expressed clinically.
Improved clinical and angiographic outcomes with Tryton in larger side branches (> 2.25 mm side branches = 41% of enrolled patients).

15. Clinical Implications
It’s difficult to enroll complex “high-risk” bifurcation lesions in clinical trials (only 41% had side branches ≥ 2.25 mm).
Small peri-procedural CK-MB elevations occur more frequently with a two-stent strategy and dominate the clinical endpoint (TVF).
Moderate stenoses in smaller side branches are not clinically active (occulostenotic paradox).
In larger side branches (≥ 2.25 mm), a Tryton two-stent strategy improved side branch angiographic results and clinical outcomes.