DRUG-ELUTING STENT SOLUTIONS

Dr. Raizner directed the Cardiac Catheterization Laboratories of the Methodist DeBakey Heart Center for twenty-five years and served as the Center’s first Medical Director. Under Dr. Raizner’s leadership, the Center achieved a ranking of 15th in the US in US News and World Report (2003). Dr. Raizner has served as a Consultant to NASA for the International Space Station project, and was part of the team of cardiologists performing the first-ever echocardiogram in space. How will DES impact the practice of interventional cardiology? With the advent of drug-eluting stents (DES), we expect the population of patients with restenosis to decline significantly. So, physicians have greater confidence treating more challenging patient and lesion types. And as the experience level of physicians using drug-eluting stents increases, we are becoming more confident in tackling more complicated lesions. Why has good stenting practice become more important in a drug-eluting stent environment? Before DES, the role of stents was principally mechanical to achieve stable lumen expansion, but with DES, stents have become a means of drug delivery. This added role obligates the interventionalist to understand and more precisely apply this sophisticated device in order to optimize the beneficial pharmacology of the stent. Why is pre-dilatation important prior to stenting? Pre-dilating the vessel before placing a DES helps prepare the artery to ensure delivery and provides important information that makes stent selection more precise. How does pre-dilatation facilitate selection of the proper stent length and size? Pre-dilatation gives a more precise guide to the diameter of the artery and a more precise estimate of the lesion length that you have to cover. DES need to cover not only the lesion, but also several millimeters beyond the lesion into more normal arterial territory, or restenosis can occur at the edges. Does pre-dilatation provide insights into lesion morphology? If a lesion’s morphology impedes good contact between the vessel wall and stent, it may limit the drug’s ability to enter the vessel wall. Pre-dilatation provides information about whether the lesion is fibrotic, calcified and resistant to balloon stretching. Physicians want to avoid inserting the stent and discovering that the lesion is so rigid that it doesn’t allow full mechanical stent deployment. You then have an "hourglass" configuration inside the stent, and have to work hard to "crack the lesion" at high pressures that may damage the lining of the vessel. What tips do you have for proper placement of overlapping stents? Clinical trial data suggest that if you leave a gap between two stents in a stenosis, the untreated segment of injured artery in that gap doesn’t benefit from the protection of the drug and becomes a site of potential restenosis. So, if we have to utilize overlapping stents, the recommendation is to overlap about four millimeters. What is the role of post-dilatation? With DES, it is crucial to get optimal stent deployment. A poorly deployed stent may increase the potential for sub-acute thrombosis. Post-dilatation after stenting helps assure that the stent has made complete apposition with the vessel wall. After all, the concept of a DES is to get the drug into the wall of the artery, so complete apposition is critical. We use a post-deployment balloon if we think the stent needs to be pushed up a notch in size, or if we are still not comfortable with the pristine appearance of the stent. When is intravascular ultrasound (IVUS) appropriate in post-dilatation? There may be advantages to IVUS if there is any measure of doubt about proper stent placement. Especially in cases involving long or complex lesions, physicians may need to double-check that complete stent apposition is present. IVUS views can visually confirm that complete apposition has been achieved. A physician might also take IVUS views to ensure that there is no gap in coverage when using multiple stents. Is there a trend towards using longer stents with DES? We’re seeing greater use of longer stents with DES. Data suggest that using longer stents to cover the entire segment of lesion seems to pay off with lower restenosis rates. Stent length should be chosen to ensure that a stent covers "from healthy to healthy," and that no part of the lesion is uncovered. With bare metal stent technology, longer lesions meant higher restenosis rates. With DES, the rate is about the same regardless of stent length. This is a big win for patients with longer lesions and challenging disease states. How have DES affected the way cath lab teams work? As technology such as DES becomes more sophisticated, and as we continue to treat more complicated lesion and patient types, teamwork in the cath lab is more important than ever. Teams must be knowledgeable about new devices and they must be able to anticipate next steps to ensure an excellent patient outcome. Sponsored by Boston Scientific Corporation.

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