Cath Lab Digest - October 2007 - (Page 25)

25 bottom line is that EVA-S3 provided physicians an opportunity to learn how to perform CAS and therefore the “learning curve phenomenon” contributed to a flawed conclusion. The only randomized controlled trial in patients who are at high risk for CEA is SAPPHIRE. The trial demonstrated cumulative major adverse event rate of 9.6% with CEA versus 4.8% with CAS at 30 days. The SAPPHIRE randomized cohort cumulative stroke rates to 3 years post procedure support the non-inferiority of CAS to CEA (7.1% vs. 6.7%). Results of CREST, ACT 1 and other studies investigating the benefit of medical therapy alone as well as CAS vs. CEA will shed more light on how best to treat the increasing number of patients with symptomatic or asymptomatic carotid artery disease. I believe CAS is at least equivalent to the 54-year-old “gold standard” practice of CEA, based on published results of multiple CAS versus CEA clinical trials, and industry-sponsored registries and post market surveillance studies. A recent pooled analysis of our own cohort of single operator symptomatic and asymptomatic high surgical risk CAS patients in the EXACT Study (Abbott Vascular) at Harrisburg Hospital recorded a less than 2% complication rate at 30 days. What do you find challenging about this procedure? I have performed nearly 1,000 CAS procedures over the last six years, and find the biggest challenge is case selection, based on my understanding of the few but serious limitations of the procedure. A CAS procedure must be properly orchestrated to include a careful and thorough evaluation of patient history and screening studies to assess the severity of the lesion and potential anatomical factors that may complicate or preclude a CAS procedure. I frequently have to assess the risk versus benefit of a CAS procedure in a symptomatic patient — this is a challenge. The decision to proceed with a CAS procedure, especially with a high surgical risk patient, must be an informed decision by the patient and the physician. The availability of improved diagnostic techniques such as CTA and MRA facilitate assessments of procedure complexity and risk. The challenge is to present to the patient and patient’s family a realistic procedure and outcome scenario to allow them to understand the risks as well as potential benefit to be derived from the CAS procedure. A recent debate has surfaced as to whether baseline intracranial angiography is required in preparation for a CAS procedure. Despite the added procedure time, I believe this procedure is an important component toward achieving a successful CAS outcome. Arch and cerebral arteriography provides critical information for guide wire placement, sheath placement and in some instances, the choice of an embolic protection device. Knowledge of normal, abnormal, and aberrant cerebral vascular anatomy, both arterial and venous, and variant arch anatomy should always be part of a CAS procedure. The identification of variant cerebrovascular anatomies and congenital or acquired defects are a sizeable challenge, yet also extremely important in proper case and embolic protection device selection. How might a carotid artery stenosis differ from a coronary or peripheral stenosis (in terms of plaque, vessel considerations, etc.)? Carotid artery stenting is predominantly about stroke prevention, either subsequently, in a symptomatic patient, or consequent to an evolving, lipid-rich “vulnerable” atheroma in an asymptomatic patient. The redundancy of the cerebral circulation with bilateral blood flow into the circle of Willis may result in a compensatory increase in flow through a contralateral internal carotid artery as an evolving atherosclerotic lesion gradually obstructs blood flow through an internal carotid artery. Stenosis within the carotid bifurcation will result in a reduction in net flow through the affected artery and with that reduced flow is an increased risk of thrombus formation at areas of flow restriction or recirculation. The objective of CAS or CEA is to stabilize (CAS) or remove (CEA) the plaque and thereby prevent arterial occlusion or worse case, a distal embolic event with significant morbidity. Coronary PCI, on the other hand, resolves ischemia mediated by a flow restriction of a critical stenosis. The reduction in coronary blood flow results in impaired A live case at Capital Cardiovascular conference (C3). myocardial function and the restoration of blood flow is the critical net result of a coronary PCI. While the coronary circulation does have some redundancy in the form of collateralization, this occurs gradually with age and in its absence, a significant reduction in coronary blood flow can result in ischemia and arrhythmia. Under normal blood flow conditions, a 50% reduction in diameter results in a 75% reduction in cross-sectional area; blood flow and area are proportional. Therefore, a 50% stenosis results in a 75% reduction in net blood flow. For peripheral vascular disease, the reduction in blood flow results in life-style limiting claudication and the potential for non-healing ulceration — restoration of blood flow through a surgical or an endovascular procedure is effective treatment of critical limb ischemia without the risk of stroke or myocardial infarction as related to CAS or coronary PCI. Has the COURAGE Trial, although not directly addressing carotid stenting patients, had an impact on your patient selection considerations? Patient selection is extremely important in determining which patient may be best treated by CAS or CEA. The COURAGE Trial brought to light the importance of proper medical management as an integral part of patient care. A very important, but frequently not stressed, component of a planned CAS procedure is patient education as to the importance of compliance with prescribed medications before and after the procedure. All patients should be encouraged to act upon lifestyle change recommendations such as smoking cessation, increased exercise, weight loss, and for diabetic patients, careful control of their glycemic index. Many labs are in the beginning stages of offering a carotid stenting program for their patients. How do you think that increasing volumes will affect patient care? Patient care will only improve provided hospital staffing is not reduced. With continued staff training and awareness of the importance of peri- and immediate post procedure surveillance and patient education, short-term and long-term CAS outcomes will continue to be excellent. The importance of proper medication prescription and compliance, as with coronary drug-eluting stents (DES), is extremely important. Staff and patients must be diligent in instruction and compliance. Clopidogrel and aspirin therapy for at least 2 months post procedure should be the minimum, with aspirin therapy continuous thereafter. Some patients may have clopidogrel resistance or variability in responsiveness to the platelet function inhibitor. The use of platelet function testing may be beneficial in identifying the occasional patient that has a peri- or post- procedure minor (TIA) embolic event due to inadequate platelet inhibition. Patient education will play a very important role in the acceptance of CAS as an alternative treatment for carotid artery disease. In time, I predict CEA will be reserved for patients at high risk of complications from CAS — for example, patients with a tortuous proximal common carotid artery, loops within the target internal carotid artery, thrombus burden, and significant arch disease. As long as the diagnostic process and case

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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