Cath Lab Digest - February 2008 - (Page 12)

12 CLINICAL TRIAL UPDATE FEBRUARY 2008 Glossary Binary restenosis: The percentage of lesions with greater than 50% luminal narrowing at the time of follow-up angiography. Endothelialization: In the early post-interventional phase, all endothelial cells are destroyed. Over time, the stent struts are recovered by a new layer of endothelium, the extent of which is termed the degree of endothelialization. Late loss: Lumen diameter reduction over time as a function of retenosis, calculated as minimal luminal diameter post-procedure (MLD) minus MLD at follow-up. • • In-stent late loss: Late loss as measured within the stent. In-segment late loss: In-stent segment plus segments 5 mm proximal and distal to the edge of the stent. Minimal luminal diameter (MLD) and percentage of stenosis are measured for each segment. (Source: Li J, Xu B, Yang Y. Drug-eluting stent for the treatment of small coronary lesion: comparison between sirolimus- and paclitaxel-eluting stents. Chinese Medical Journal 2007;120(7):569-573.) P-value: a measurement of statistical significance. The higher the p-value, the less the likelihood that the observed relation between variables in the sample is a reliable indicator of the relation between the respective variables in the population. Typically, in many sciences, results that yield p ≤ .05 are considered borderline statistically significant, but remember that this level of significance still involves a pretty high probability of error (5%). Results that are significant at the p ≤ .01 level are commonly considered statistically significant, and p ≤ .005 or p ≤ .001 levels are often called “highly” significant. (Source: “Elementary Concepts in Statistics.” Electronic Texbook by StatSoft. Available at: http://www.statsoft.com/textbook/esc.html#What%20is%20%22statistical%20significance%22%20(p-level) Accessed May 17, 2007.) Target lesion revascularization (TLR): Revascularization at the lesion where the initial intervention occurred — includes the stent site and 5 mm outside the stent. Target vessel revascularization (TVR): Revascularization anywhere within the same vessel as the originally treated lesion (although not necessarily the same lesion). Target vessel failure (TVF): A measurement of target vessel revascularization, death, or myocardial infarction. dual anti-platelet regimens. Of course, carefully planned clinical trials will be required to prove that Endeavor is truly safe from the standpoint of stent thrombosis, despite only one, two or three months of clopidogrel therapy. In addition, the Endeavor stent has been expanded to include the Resolute platform. The CE mark approved Resolute drug-eluting stent, compared with Endeavor, is the same stent, same balloon catheter, same drug and drug dose, but has a different drug carrier vehicle. This custom biostable hydrophilic polymer is called BioLinx and dramatically extends the drug elution time. Rather than eluting very quickly over the first few weeks, BioLinx elutes the drug slowly over a three-month period. Early clinical studies outside the U.S. indicate very low late loss with Resolute, comparable to the best sirolimus and everolimus-eluting stents. With the Resolute platform, you will have an extremely effective drug-eluting stent from the standpoint of low late loss, but the question now is, will it be as safe as the parent Endeavor platform from the standpoint of stent thrombosis? These are certainly interesting questions for future clinical trials. With respect to clinical scenarios in which Endeavor should be used after FDA approval, obviously this is rather subjective and will vary depending on operator preferences and the kinds of patients and lesions treated. Clearly, difficult to reach coronary lesions would be a good group of cases for Endeavor, as it is highly deliverable. Also, due to the improved safety margins, many of the patients currently treated with bare-metal stents due to concerns about long-term clopidogrel use might also be good candidates for Endeavor. I would certainly not be surprised if Endeavor becomes among the most widely used drug-eluting stents in the U.S. over the next year. Finally, I would like to note that several key individuals have contributed importantly to the Endeavor clinical program, including Dr. Laura Mauri from the Brigham and Women’s Hospital, Dr. Jeffrey Popma, the director of the core angiographic lab, and Dr. Peter Fitzgerald, the director of the core intravascular ultrasound lab. ■ Dr. Leon can mleon@crf.org. be contacted at 2 years and 675 patients at 3 years. These data have indicated a very low frequency of late and very late stent thrombosis with Endeavor, by both protocol and ARC (Academic Research Consortium) definitions, results which are similar to a baremetal stent and improved compared to current FDA-approved drug-eluting stents. Including the ongoing studies, Endeavor will be the most completely studied drug-eluting stent for both onlabel and more “real world” off-label indications. This should give interventional operators and patients a feeling of confidence and reassurance that there will be no efficacy and safety surprises with Endeavor in the future. Do you think the ease of deliverability will favor an increased use of the Endeavor stent in more complex cases (which may also affect measured realworld outcomes)? Yes, definitely. In most cases, you can ultimately deliver a Cypher or a Taxus stent, but as the operator, you often have to use stiffer guidewires, or predilate more aggressively, or use a larger guiding catheter for increased support in order to “muscle” the stent down the coronary tree. The experience of having to deliver out-of-date stiff drug-eluting stents will be gone with Endeavor. I think it will make things a lot easier for operators, much more analogous to putting in modern thin-strut and highly flexible baremetal stents. This improved ease-ofuse with Endeavor will likely result in its use in more complex and difficult to reach coronary lesions, such as calcified lesions or in situations of increased vessel tortuosity. What lies ahead? We still need more studies to address unanswered questions, especially the issues of long-term safety and the duration of dual anti-platelet therapy. The duration of dual anti-platelet treatment with Endeavor is going to be an interesting question, because we are not certain that patients will need the recommended full one year of therapy. In ENDEAVOR II, III and IV, dual anti-platelet therapy was either 3 or 6 months. Until more data are available, we expect that the Endeavor instructions for use will still conform to the American College of Cardiology/American Heart Association guidelines, where dual anti-platelet therapy is recommended for one year for all drug-eluting stents. Experimental studies with Endeavor indicating healing properties close to bare-metal stents and preliminary clinical data also suggesting comparable safety to bare-metal stents, leaves open the possibility that Endeavor may allow shorter-term

Table of Contents Feed for the Digital Edition of Cath Lab Digest - February 2008

Cath Lab Digest - February 2008 Bay Regional Medical Center ENDEAVOR IV: A Zotarolimus-Eluting Stent Versus a Paclitaxel-Eluting Stent in a Randomized Clinical Trial A 3D CT Vessel “Roadmap” Over Live Fluoroscopy for Chronic Total Occlusions Contents Clinical Editor’s Corner An Evaluation of Cath Lab Turnaround Time Commentary: An Evaluation of Cath Lab Turnaround Time Excerpts from Chapter 19. STEMI Interventions – Future Perspectives The Potential Clinical Utility of Intravascular Ultrasound Guidance in Patients Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents The Ten-Minute Interview with…Debbie Charlton, RN The Society of Invasive Cardiovascular Professionals (SICP) at Transcatheter Cardiovascular Therapeutics (TCT) 2007 The Cath Lab is a Business: Do You Have the Knowledge to Stay Afloat? Incidence and Predictors of Vascular Complications after Invasive Coronary Procedures: A Prospective Analysis Ask the Clinical Instructor: A Q&A Column for those New to the Cath Lab Volunteer Survey SICP* Section Meetings Calendar What Do You Think? CEU Education Center Clinical & Industry News Classifieds Advertisers Index

Cath Lab Digest - February 2008

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