Next-Generation Drug-Eluting Stents

Author(s): 

By Cindy L. Grines, MD, FACC
Vice Chief of Academic Affairs,
William Beaumont Hospital,
Division of Cardiovascular Medicine,
Royal Oak, Michigan

This monthly column in Cath Lab Digest reviews important points of distinction in drug-eluting stents, from characteristics to techniques, to provide valuable and relevant information about this technology.

Dr. Grines is the Vice Chief of Academic Affairs, Division of Cardiovascular Medicine, at William Beaumont Hospital in Royal Oak, Michigan. In 1989, Dr. Grines initiated the first Primary Angioplasty in Myocardial Infarction (PAMI) study. Since that time, she has designed and completed seven additional PAMI studies. Dr. Grines has authored numerous book chapters and hundreds of medical journal articles regarding cardiac catheterization, angioplasty, acute myocardial infarction, chemical intervention to break down arterial blockage and gene therapy. She is editor-in-chief of the Journal of Interventional Cardiology and participates on the editorial boards of several medical journals. Dr. Grines received her medical degree from Ohio State University. Her internship and residency were at the Ohio State University Hospitals, and she completed a cardiology fellowship at the University of Michigan. She is board-certified in internal medicine, cardiovascular disease and interventional cardiology.

Recently the PROMUS™ Stent received U.S. Food and Drug Administration (FDA) approval. What importance does this mark in the interventional community?

The FDA approval of the PROMUS Stent is noteworthy for the interventional community. There is increasing evidence that strut thickness may influence performance. Stents with thinner struts are exceptionally deliverable due to their increased flexibility, while still offering radial strength to support the vessel wall. The availability of the PROMUS Stent offers interventional cardiologists an exceptionally deliverable -olimus stent.

What does the clinical data suggest about the effectiveness of the PROMUS Stent?

The SPIRIT Clinical Trial Program demonstrates that the PROMUS Stent has low rates of restenosis and late loss. If one looks at the ability to successfully deliver the PROMUS Stent, it is quite high. Rates of mortality, myocardial infarction (Q-wave and non-Q-wave) and target lesion revascularization (TLR) are very low. A U.S.-based trial that I’m quite excited about is called the PROMUS Study. Along with Dr. Ted Feldman, I’ll be a Co-Principal Investigator and we look forward to initiating this trial, which will further study the PROMUS Stent in a large number of real-world patients.

How do you think the PROMUS Stent compares to the other
“-olimus” stents?

In general, the -olimus types of drugs are thought to have lower late loss rates. The PROMUS Stent provides an exciting new alternative. Its thin strut design and exceptional deliverability make it an attractive option for U.S. patients and their physicians, and it elutes an -olimus type of drug, which has been shown to have the lowest late loss rates of any drug out there.

How does the PROMUS Stent differ in terms of safety and efficacy compared to other olimus-eluting stents on the market from Johnson & Johnson and Medtronic?

These olimus-eluting stents have not yet been evaluated in any head-to-head clinical trials. The first such trial is a European registry called PROENCY. Until results are available from this European study that matches these competing stents against each other, we really have no means of direct comparison on which to base safety and efficacy claims. But this is data we are all very interested in seeing when it becomes available.

How does the PROMUS Stent perform in terms of long-term safety and effectiveness?

Two-year data from the SPIRIT III Trial, presented in May 2008 at the EuroPCR meeting in Barcelona, confirmed consistent, positive and durable clinical results for Boston Scientific’s PROMUS Everolimus-Eluting Stent, including positive safety and efficacy data and low stent thrombosis rates.

What lies ahead for new drug-eluting technologies?

Clearly, there is a lot of interest in bioresorbable stents. Drug elution disrupts early inciting events that elicit restenosis, but once the drug is no longer present – typically after two to four weeks – the stent remains indefinitely. There has been huge interest in developing stents that contain the drug but no polymer, and stents that are completely biodegradable, meaning that both the polymer and metal eventually disappear. Early data is limited for these investigational stents. For example, there may be more recoil of the vessel after the stent is no longer there, or there may not be enough radial support to prop open the vessel, but I think eventually there will be a solution.

Another technology that is quite interesting are stents that have been coated with materials that enhance endothelialization. For example, these so-called “pro-healing” stents can be coated with antibodies that attract endothelial cells and, in turn, may help reduce stent thrombosis. Other stents are in development that have differences in texture, which helps endothelial cells better latch on to the stent.

Cypher is a trademark of Cordis Corporation.

The PROMUS Stent is a private-labeled XIENCE V Everolimus-Eluting Coronary Stent System manufactured by Abbott and distributed by Boston Scientific Corporation.

XIENCE is a trademark of Abbott Laboratories group of companies.

The SPIRIT trials are sponsored by ABT.

Sponsored and prepared by Boston Scientific Corporation.

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