Treating Saphenous Vein Grafts With Distal Embolic Protection Devices

This month’s column in Cath Lab Digest reviews embolic protection systems, from characteristics to techniques, so that physicians and allied health professionals have valuable and relevant information about this revolutionary technology. By Henry Lui, MD Dr. Lui is a Medical Director at the West Tennessee Heart Center in Jackson, TN, and is in private practice at Apex Cardiology, also in Jackson. Dr. Lui is actively involved in clinical research and serves as Director of Research at Research Associates of Jackson. Dr. Lui received his bachelor’s degree at the University of California at Berkeley and his medical degree at the University of California at Davis Medical School. He completed his cardiology fellowship at the University of California at Davis Medical Center. Dr. Lui is a Fellow of the American College of Cardiology and the Society for Cardiac Angiography and Interventions. In what percentage of saphenous vein graft (SVG) cases do you use embolic protection? I use embolic protection in 100 percent of SVG cases, if at all possible. This is also true for carotid interventions. In my experience, I have found it to be extremely important to use distal embolic protection because various clinical trials show benefits in terms of decreasing major adverse events. There are only a few, rare cases in which I do not use embolic protection. For instance, I don’t use it in cases in which I cannot place the device or in which there is an inadequate “landing zone” (e.g., not enough room to place the distal protection device) because of the location of the lesion. With newer devices such as the FilterWire EZTM 2.25-3.5mm System, the landing zone is greatly reduced so that it can be used in more distal lesions. What do you like about the FilterWire® System? I have found the FilterWire System to require very little preparation time and to be extremely simple to deploy. It’s preloaded and is easily advanced across most lesions. Additionally, it has very efficient debris capture due to a 110-micron-pore filter1 that is designed to allow continuous blood flow while maintaining embolic capture efficiency. Its radiopaque loop enables full deployment verification with one angiographic view and works well in both curved and straight anatomy. The FilterWire System is a versatile system that I have used in carotid interventions, as well as for SVG cases. What would you like to see improved about embolic protection? Occasionally, I have to use a buddy wire or a small balloon to pre-dilate the lesion because it is so tight, so I would say that crossability could be improved. We could have a better success rate if we did not have to resort to fancy maneuvers to cross very tight lesions. Shorter landing zones might also improve success rates. You used the newly available FilterWire EZ 2.25-3.5 System during the BLAZE II SVG registry. What did you like about it? The FilterWire EZ 2.25-3.5mm System has a shorter landing zone than the FilterWire EZ 3.5-5.5mm System because its wire tip is shorter. Additionally, it can be used in much smaller vein grafts and in very distal lesions. You can almost place the filter in the native vessel itself or close to it. With the new FilterWire EZ System, the learning curve is the same as the regular, larger FilterWire EZ System. In fact, if you know how to use the FilterWire EZ 3.5-5.5mm System, you can use the smaller FilterWire EZ 2.25-3.5mm System very easily. What recommendations do you have for other interventional cardiologists and cath lab staff when using embolic protection devices and FilterWire System? One issue of which interventional cardiologists and cath lab staff need to aware is that certain takeoffs on the vein graft — especially those to the obtuse marginal artery — may come off high. In these cases, I recommend using a specialty curve guide catheter, such as the Boston Scientific allRight™ ART3, ART3.5 or sometimes even an ART4 guide, which provide much better support and allow for the advancing of the FilterWire System more easily. As I mentioned before, a buddy wire may help to facilitate delivery of the FilterWire System when lesions are very tight. On rare occasions, I may have to predilate with a 2.0-mm Maverick™ balloon before I am able to advance the FilterWire System across a very tight lesion. Sometimes, I may choose to do this in carotid interventions as well. Interventional cardiologists have to be very industrious to get across tight lesions. Even in cases where it has been very difficult to advance the FilterWire System, I have eventually been able to advance it across the lesion. My advice to other interventional cardiologists is to not give up. Use finesse to get the job done. Why do you use embolic protection devices? Using distal embolic protection has been proven to capture embolic material, resulting in low major adverse cardiac events (MACE). In the Saphenous vein graft Angioplasty Free of Emboli Randomized (SAFER) trial, distal embolic protection proved to be effective in capturing embolic material, which led to a 42-percent reduction in MACE rates.2 In the FilterWire EX® Randomized Evaluation (FIRE) Trial, low MACE rates were also observed.3 The BLAZE I and II studies together demonstrated further low rates in MACE, possibly due to interventional cardiologists getting more comfortable in using distal embolic protection. In both trials, there was a 98-percent device success rate.4 (Editor’s Note: The SAFER Trial was a 801-patient, multi-center, randomized study performed to assess the safety and performance of the Guardwire embolic protection device in patients during SVG percutaneous interventions. The FIRE Trial was a 651-patient, multi-center, randomized study of the FilterWire EX System versus GuardWire to prove non-inferiority of the FilterWire EX System in SVG interventions. BLAZE [n=90] and BLAZE II [n=131] were prospective, multi-center, non-randomized studies performed to assess the safety and performance of the FilterWire EZ System in patients during SVG interventions.) Based on your clinical experience and currently available society guidelines, do you think that embolic protection systems should be the standard of care in all SVG cases, when feasible? Yes. While some interventional cardiologists are hesitant to use embolic protection because it requires additional time, if you choose not to spend a few extra minutes to use embolic protection you may risk a major adverse event, such as a non-ST segment elevation myocardial infarction (STEMI) or even a STEMI. As far as the guidelines are concerned, the American College of Cardiology (ACC)/American Heart Association (AHA)/Society for Cardiovascular Angiography & Interventions (SCAI) recommendation is for Class I use, and this is because the clinical trials have shown that distal embolic protection devices offer benefit in improving outcomes in all of our patients. Financial and editorial support for this article provided by Boston Scientific. Guardwire is a trademark of Medtronic Vascular, Inc.

1. Data on file at Boston Scientific, Inc. 2. Baim DS, et.al., Circulation. 2002;105:1285-1290. 3. Stone GW, et.al., Circulation. 2003;108:548-553. 4. Refer to FilterWire EZ System Directions for Use, available at www.bostonscientific.com/filterwire.