Cath Lab Digest - October 2007 - (Page 26)

CLINICAL UPDATE OCTOBER Closed cell stents present a higher metal-to-artery ratio and therefore may provide better wall apposition for plaque containment and a higher radial force to resist compressive forces exerted by the muscular arterial wall. selection process leading toward a decision to perform CAS is informed through current advanced diagnostic technologies (CTA and MRA), the volume of procedures will increase and patient care should only improve. What characteristics do you anticipate for the next generation of carotid stenting systems and embolic protection devices? Filter-based devices having smaller parking space requirements, pore size refinements, filter devices preloaded in their delivery catheter, and refinement of reverse flow protection devices are areas of device research and development that warrant further effort. No reflow and/or vasospasm in the area of filter deployment is an occasional problem with distal embolic protection devices. When a no reflow situation presents post-stenting, I routinely use an aspiration catheter (e.g. QuickCat by Kensey Nash) as a precautionary measure, not knowing if an occluded filter or spasm has affected blood flow through the distal perfusion holes of the filter device. Perhaps the application of a hydrophilic coating to the filter membrane would increase surface lubricity and reduce any spastic stimulus by the device. The development and refinement of guide wires and guide sheaths specific for carotid application will be welcome; a good example of this technology is the Morph deflectable guide sheath (BioCardia, Inc.) and Strada sheath (St. Jude Medical, in development) which in challenging anatomy facilitates guide/sheath placement into the common carotid artery. Gaining safe guide wire access across a high-grade stenosis or calcified ostium is challenging with increased risk of doing harm prior to the actual CAS deployment. The Venture Catheter (St. Jude Medical) is another device that may be invaluable in gaining guide wire access across calcified or otherwise challenging access scenarios. Also, the Emboshield PRO (Next generation filter system, Abbott Vascular) is currently under trial in U.S. and may possess many of the refined characteristics described earlier. The merits and demerits of open and closed-cell stent designs for CAS are a topic of discussion. I routinely use a laser-cut closed cell design self-expanding (SE) stent for the majority of CAS procedures performed at Harrisburg Hospital. I will use an open cell SE stent for a lesion within or just proximal to a tortuous arterial segment; the open cell stent conforms to the bend and is less apt to result in a pseudospasm distally. Closed cell stents present a higher metal-to-artery ratio and therefore may provide better wall apposition for plaque containment and a higher radial force to resist compressive forces exerted by the muscular arterial wall. There is no argument that closed cell stents straighten the artery and may result in pseudospasm distally, which rarely is a problem once the sheath has been removed from the common carotid artery. The two approved close cell stents in the U.S. are Xact (Abbott Vascular) and NexStent (Boston Scientific). Subacute thrombosis has not been a concern with CAS and there does not seem to be a need for DES technology in the treatment of carotid artery disease. Restenosis and thrombosis are extremely rare subsequent to CAS. Can you describe how your practice has evolved since your first involvement with carotid stenting? I arrived in Harrisburg in 2001 and joined Associated Cardiologists with the intent of bringing a CAS program to the central Pennsylvania community. At that time, CAS was not a FDA-sanctioned procedure and I became an investigator in the Abbott Vascular Devices Xact Carotid Stent pivotal study. Since then, multiple systems have been commercialized through the clinical trial and registry process, and CAS is now available to many patients who qualify based on the current guidelines set forth by FDA and CMS. Recent reversals in the “acceptable criteria” for a reimbursable CAS procedure have unfortunately made CAS less available to some patients. I remain confident that with time and continued data collection, review and comparison the safety, efficacy and longterm durability of CAS will be demonstrated. CAS is available to many patients due to the support of industry and FDA through the large number of randomized trials and post-market approval registries mentioned earlier. How are you seeing physicians with different backgrounds, such as surgery and radiology, consult or work together for the benefit of carotid stenting patients? My own experience has been excellent in terms of the working relationship with my surgical and neurological colleagues. Harrisburg Hospital and I have also conducted CAS-specific training courses for Abbott Vascular, Boston Scientific, eV3 and Cordis Corporation. What I find most interesting of late is the increase in the number of vascular surgeons attending the CAS training courses. Initially interventional cardiologists predominated course attendance with interventional radiologists and interventional neurologists showing an increased presence after the first year of course availability. Today, I notice an increasing number of vascular surgeons attending and anxious to learn guide wire and catheter skill sets, and technique for cerebrovascular arteriography and CAS with embolic protection. Physicians with formal and practice training in related but different disciplines required for CAS recognize that a gradual transition to CAS as an acceptable and perhaps patient-driven alternative to CEA will occur over the next few years and want to be part of this effective treatment modality. We are all aware that the increasing number of elderly patients and morbidity of stroke warrant the treatment of significant carotid artery disease as a preventative measure. The device industry needs to continue their excellent training programs, which will prove vital in years to come in the success of this procedure for the interventional community. Also, forums like Capital Cardiovascular Conference (C3) (www.ccmcme.com/c32007) provide a great venue to learn technical aspects of this very simple-appearing but very complex procedure to ensure better outcomes for any specialists. Just recently concluded, C32007 had demonstrated technical tips for complex octagenerian CAS procedures and vertebral procedures to ensure success. Looking ahead, do you envision interventionalists one day moving beyond the carotids into the cerebrovascular realm? Interventional neurologists already are very actively treating complex congenital and cerebrovascular disease. Stroke intervention is common with advanced technologies such as the Merci Clot Retriever (Concentric Medical), developed specifically to aggressively help patients with ischemic stroke. Stroke treatment is a logical area for interventional therapy and without involvement of interventional cardiology community, all the patients who need this life-saving procedure will never be treated, as there are just not enough dedicated neurointerventionists. However, many hurdles, including reimbursement, etc., remain. To quote a group of respected vascular surgeons who now also perform CAS: “The authors concluded that vascular surgeons who possess advanced catheter-based skills can safely perform CAS with results comparable to CEA. Vascular surgeons essentially have three choices when it comes to CAS. We can either lead, get out of the way, or be trampled by the onslaught of other specialists all chomping at the bit to be the principle negotiator in this very common disease process.”2 ■ Dr. Dave can be contacted at rdintervention@yahoo.com 1. Mas J, Chatellier G, Beyssen B, et al, for the EVA-3S Investigators. Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis. N Engl J Med Oct 2006;355:1660–1671. 2. Eskandari MK, Longo M, Matsumura JS, et al. Carotid stenting done exclusively by vascular surgeons: First 175 cases. Vascular Surgery and Endovascular Therapy Outlook 2006; 18:1. References www.ccmcme.com/c32007

Table of Contents Feed for the Digital Edition of Cath Lab Digest - October 2007

Saints Medical Center Fibromuscular Dysplasia in Children and Adolescents Cerebral Vascular Accident Following a Pulmonary Embolism: Search for the Hidden Patent Foramen Ovale Contents Clinical Editor’s Corner Meetings Calendar CEU Education Center Radiation Tracking in the Cardiac Catheterization Lab Letter to the Editor Carotid Stenting: An update Release from Stent-jail: Beneficial Snow-Plowing? Patient Management Guidelines Searching for a Cardiovascular Position? Tips for Creating a ‘Stand-Out’ Resume Long-Term Implications of Short-Term Closure Decisions – The Evolution to Vascular Access Management and the Boomerang Catalyst System The Ten-Minute Interview with… Angie Bowles, RN, CCRN CMS Issues Final FY 2008 IPPS Rule ACVP• Membership Page Experience with a New Workhorse Guidewire Ask the Clinical Instructor: Q&A for Those New to Cath Lab A Glimpse of the Future of Clinical Education: Boston Scientific’s SimSuite Bus Visits Carnegie Institute 2007 Educational Fair Held at the Washington Hospital Center Research Update: Original Contribution Abstracts from The Journal of Invasive Cardiology What Do You Think? A Virtual Cath Lab Viewer (VCL): The Development of an Online 3D C-arm Simulator and Coronary Anatomy Viewer Clinical & Industry News Cost-Effectiveness of the Radial versus Femoral Artery Approach to Diagnostic Cardiac Catheterization

Cath Lab Digest - October 2007

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