When most people in the medical tech field think of stents, they envision a straight (though occluded) atherosclerotic vessel being pushed open via a balloon catheter so that the stent can be placed. But how do you deposit a stent right at the site of a vessel bifurcation, without blocking flow to either of the smaller vessels? Unfortunately, due to turbulent flow around these bifurcations there are often shear forces that can lead to vessel damage and eventually plaque formation. The medical device company Tryton Medical, which we’ve covered before, has a unique stent that is designed for this scenario. We spoke with their CEO Shawn McCarthy to learn more about the technology and market.
Shiv Gaglani, Medgadget: Can you describe the technological innovation behind the stent?
Shawn McCarthy: The Tryton Side Branch Stent™ (Tryton) is an innovative endovascular prosthesis designed for the definitive treatment of coronary artery bifurcations. This device incorporates several technological innovations: the method in which it is utilized is revolutionary; the delivery system is a stepped balloon; and the stent has three unique zones designed specifically for three different portions of the bifurcation.
The Tryton is a balloon-expandable stent manufactured from a single piece of medical grade L-605 cobalt chromium (CoCr) alloy tubing. This alloy can be formed into thinner stent struts than traditional stainless steel (316L) stents, and provides a more flexible, low profile system while maintaining a balance of adequate radiopacity and strength. The Tryton has a single device that incorporates three distinct zones to treat the side branch, the transition from the side branch to the main vessel, and the proximal main vessel portion of the bifurcation in a single device. With the Tryton, stent properties such as radial strength, scaffolding, and flexibility are optimized for each zone in order to definitively treat the bifurcation. Unlike standard coronary stents which look like cylinders, the Tryton looks both cylindrical and conical; matching the underlying geometry of a coronary bifurcation.
The Tryton delivery system is based on a rapid exchange, coronary balloon catheter with several unique features. The balloon used to deploy the stent has three zones which mate themselves to the three zones on the stent and the corresponding geometry of the bifurcation. Utilizing a single inflation device all three zones achieve their intended diameter simultaneously. The delivery system utilizes a four marker delivery system allowing the physician to see the precise location of each zone during device implantation. Finally, this complex catheter meets or exceeds the performance criteria established for standard balloon catheters.
Medgadget: How large is the market you’re addressing with the SHORT stent? Can you describe the various use cases?
McCarthy: It’s estimated that 20-30% of all PCI’s (stenting procedures) involve a bifurcation, the majority of which are high risk lesions, which are appropriate side branch stenting candidates. This equates to the potential for 500,000 annual bifurcation stent procedures globally. The Tryton Side Branch SHORT stent broadens bifurcation treatment options in large vessels with a SHORT main branch landing zone, potentially offering a solution for an additional 200,000 procedures annually.
Medgadget: What other options are there for these patients?
McCarthy: Current approaches to treating these lesions include provisional balloon angioplasty, primarily focusing on treating disease in the main vessel. This treatment strategy can be time consuming and technically difficult. As a result, the side branch is often left unstented, leaving it vulnerable to higher rates of restenosis, the re-narrowing of the artery after intervention.
Medgadget: Have clinical trials been performed and, if so, can you discuss the design and results?
McCarthy: Data from more than 1,000 patients collected in 8 registries across Europe treated with the Tryton stent are already challenging provisional stenting, with compelling results of target lesion revascularization of four percent and thrombosis of 0.5 percent at one year. With more than 7,500 implants to date, we are leveraging our impressive data to further expand globally.
We completed enrollment last November in the landmark Tryton pivotal IDE study, a multi-national randomized trial that compares a Tryton stent in the side branch vs. the use of balloon angioplasty in the side branch, with both arms of the trial utilizing a standard drug eluting stent in the main vessel. The study, which is the first and only randomized IDE pivotal clinical trial evaluating a dedicated bifurcation stent, enrolled 704 patients at centers in North America, Europe and Israel. Martin Leon, M.D. (Columbia University, New York) serves as principal investigator for the study and Patrick Serruys (Thoraxcenter, Rotterdam) is leading IVUS and three-dimensional angiographic analysis.
We anticipate our pivotal IDE results to be presented at the TCT Conference in October 2013, submitted to FDA by end of year, and approved in the US in 2014. We are on track to be the first and only approved stent for coronary bifurcations in the U.S.
Medgadget: What is your background in health tech?
McCarthy: I have more than 20 years of experience commercializing medical device products globally, over half of that time with Johnson & Johnson. A major focus for me has been to provide minimally invasive solutions for patients suffering from Vascular disease – across Cardiovascular, Endovascular, and Neurovascular markets.
Medgadget: Are you excited by any specific trends in medical innovation/technology?
McCarthy: Medical innovation is going with the grain, meaning startups are taking their businesses further along the maturity curve in a complex business environment – developing devices that generate compelling data, fitting routine physician practice patterns, and offering health economic evidence that suggest an innovative treatment strategy is not only safe and effective, but reasonable and necessary. Startups demonstrating the ability to navigate sophisticated global regulatory environments quickly and effectively.
Product page: Tryton Side Branch Stent…
