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)

The Tryton Side Branch Stent System has been designed to address the procedural difficulty surrounding treatment of bifurcation lesions and to ensure patency of the side branch with similar performance capabilities (e.g., tracking, radiopacity, coverage and radial strength) that are currently available with conventional coronary stents designed for straight (non bifurcation) lesions.

The Tryton Side Branch Stent is intended to treat and maintain patency in the side branch/carina by providing better ostial side branch conformability and is intended for use in conjunction with currently approved balloon-expandable drug-eluding stents for treatment of the main branch.

The use of drug-eluding stents in the treatment of bifurcation lesions suggests that DES reduces the rate of restenosis int he main branch (5-10%); however, results int he side branch are not optimal. A study of T stenting in true bifurcation lesions showed a restenosis rate int he main branch of approximately 6% using the CYPHER stent. However, the same study demonstrated that the restenosis rate remained high int he side branch (20%) despite stent implantation and when restenosis occurs, it is generally located at the ostium of the side branch. Further, in half the cases where PTCA alone was the intended strategy for the side branch, a side branch stent had to be placed to address sub-optimal procedural results.

These findings are consistent with previous metal stent studies and suggest the best long-term results are obtained when a side branch stent is not placed. This study and others suggest that the outcomes are related to the way the stents sit within in the vessel; and therefore a stent designed specifically for bifurcation lesions will be needed to reduce restenosis rates and improve long-term outcomes.

Inclusion Criteria:

• The patient must be ≥18 and ≤ 90 years of age;
• Symptomatic ischemic heart disease (CCS class 1-4, Braunwald Class IB, IC, IIB, IIC, IIIB, IIIC, and/or have objective evidence of myocardial ischemia);
• Acceptable candidate for CABG;
• Intent to treat the side branch of the target bifurcation based on angiographic evaluation;
• The patient is willing to comply with specified follow-up evaluations;
• The patient or legally authorized representative has been informed of the nature of the study, agrees to its provisions and has been provided written informed consent, approved by the appropriate Medical Ethics Committee (MEC) or Institutional Review Board (IRB).
• Planned use of one of the following approved and commercially available drug-eluting stents for subject's index procedure: CYPHER®, ENDEAVOR® RESOLUTE, PROMUS® or PROMUS® ELEMENT, XIENCE™ V or XIENCE PRIME.

General Exclusion Criteria

• Pregnant or nursing patients and those who plan pregnancy in the period up to 1 year following index procedure. Female patients of child-bearing potential must have a negative pregnancy test done within 7 days prior to the index procedure per site standard test;
• Patient has had a known diagnosis of STEMI acute myocardial infarction (AMI) within 72 hours preceding the index procedure or >72 hours preceding the index procedure and CK and CK-MB have not returned to within normal limits at the time of procedure;
• Patients with non-STEMI within 7 days prior to index procedure with continued CK-MB elevation;
• Patients with non-target lesion PCI within 7 days prior to index procedure with continued CK-MB elevation;
• Impaired renal function (serum creatinine >2.5 mg/dL or 221 μmol/l) or on dialysis;
• Platelet count <100,000 cells/mm3 or >700,000 cells/mm3 or a WBC <3,000 cells/mm3;
• Patient has a history of bleeding diathesis or coagulopathy or patients in whom anti-platelet and/or anticoagulant therapy is contraindicated, or any other significant medical condition which in the Investigator's opinion may interfere with the patient's optimal participation in the study;
• Patient has received an organ transplant or is on a waiting list for any organ transplant;
• Patient has other medical illness (e.g., cancer, known malignancy, or congestive heart failure) or known history of substance abuse (alcohol, cocaine, heroin etc.) that may cause non-compliance with the protocol, confound the data interpretation or is associated with a limited life expectancy (i.e., less than 1 year);
• Patient has a known hypersensitivity or contraindication to aspirin, heparin/bivalirudin, clopidogrel/ticlopidine, prasugrel, stainless steel alloy, cobalt-chromium alloy, rapamycin, everolimus, zotarolimus, paclitaxel, and/or contrast sensitivity that cannot be adequately pre-medicated;
• Patient presents with cardiogenic shock or cardiac arrhythmias that create hemodynamic instability;
• Patient in whom a surgical or other procedure is planned within the next year which would require discontinuation of dual antiplatelet therapy;
• Currently participating in another investigational drug or device study or patient inclusion in another investigational drug or device study where the primary endpoint of the study has not been reached.