Cath Lab Digest - April 2008 - (Page 50)

50 ACC NEWS APRIL 2008 1-Year Results Promising in Small Study of MitraClip A catheter-mounted device that acts like a clothespin to clip together the flaps of a leaky heart valve is not only reducing the abnormal backflow of blood from the left ventricle to the left atrium, it is helping to shrink the enlarged, overworked heart and relieving symptoms of fluid overload — all without open-chest surgery. These are the one-year findings in a small group of patients enrolled in the Endovascular Valve Edge-to-Edge Repair Study (EVEREST), which is evaluating the use of the MitraClip for the treatment of mitral regurgitation (MR). The sub-analysis was reported in a LateBreaking Clinical Trials session at the SCAI Annual Scientific Sessions in Partnership with ACC i2 Summit (SCAI-ACCi2) in Chicago. “One trouble with mitral regurgitation is that the heart has to work harder, and over time, it dilates and enlarges,” said James Hermiller, MD, director of the interventional fellowship at St. Vincent Heart Center of Indiana in Indianapolis. “Demonstrating that the left ventricular enlargement is actually reversing itself is important objective evidence that the heart is responding favorably. It confirms that there’s something real here.” Mounted on the end of a catheter, the MitraClip is threaded through the femoral vein in the groin and into the right atrium. A needle puncture in the wall separating the upper chambers of the heart enables the catheter to pass into the left atrium, where the clip is opened up like a clothespin. It is then passed through the mitral valve into the left ventricle. When the heart contracts, the flaps of the mitral valve are grasped by the clip, which is then closed, securing the edges of the valve flaps together at their centers. The result is a bow-tie-shaped opening that permits blood flow from the left atrium to the left ventricle during relaxation of the heart, and enables the valve flaps to close more effectively during contraction, rather than allowing leakage of blood backward into the left atrium. The study by Dr. Hermiller and his colleagues focused on 23 patients treated at 15 medical centers either during the EVEREST I study or during the “roll-in” phase of the ongoing EVEREST II study, which is comparing MitraClip therapy to open-chest surgery. All of the patients in the new analysis had functional MR, which results not from a defect in the valve leaflets but from enlargement of the valve opening as a result of heart attack or heart failure. Of the quarter-million people newly diagnosed with mitral regurgitation in the United States each year, as many as two-thirds have the functional form, but it hasn't been clear whether the MitraClip would work as well in functional MR as in degenerative MR. Before the procedure, all patients had moderately severe or severe mitral regurgitation, and 83 percent of patients had heart failure ranked as New York Heart Association (NYHA) functional class III or IV, which is characterized by lung congestion, shortness of breath, fatigue, swelling of the legs, and difficulty with light-to-moderate physical activity. After the procedure, mitral regurgitation was mild to modest in 19 of 22 patients (83 percent) treated with the MitraClip. After one year, 12 patients had completed followup and had matched data from both baseline and follow-up. Ten of the 12 patients (83 percent) continued to have only mild to modest mitral regurgitation and nine of 12 (75 percent) continued to enjoy an improvement in symptoms and daily function of at least one NYHA class. In addition, heart size was significantly smaller. For example, the left ventricular internal diameter during relaxation, or diastole, fell from an average of 6.0 cm at baseline to 5.4 cm at 12 months (p=0.037), and left ventricular end-diastolic volume fell from an average of 208 mL at baseline to 178 mL at 12 months (p=0.037). “This is a small study, but it demonstrates a proof of principle that the MitraClip can reduce mitral regurgitation and improve heart function in patients with functional MR,” Dr. Hermiller said. “These findings are promising and interesting, but clearly we need a lot more data.” ■ Real-World Data from ARRIVE Registries Show Favorable Outcomes for Taxus® Express™ Stent B oston Scientific Corporation announced results from an analysis of two-year data from more than 7,000 patients in the TAXUS ARRIVE Registry program. The study was designed to evaluate the safety performance of the TAXUS ® Express2 ™ PaclitaxelEluting Coronary Stent System in patients treated in “real-world” practice. Outcomes through two years in the simple-use (single vessel/stent) patient group confirmed the favorable results seen in similar patients enrolled in previous TAXUS randomized clinical trials (the clinical trial cohort). Results in the more complex expanded-use group also continued the expected slightly higher event rates than simple-use patients, but were still favorable through two years compared to the published outcomes of other treatment modalities for such patients. Analysis of the data was presented by John M. Lasala, MD, PhD, at the SCAI Annual Scientific Sessions in Partnership with the ACC i2 Summit in Chicago. “The extensive ARRIVE data show favorable and consistent outcomes in high-risk groups representing some of the most complex patients and lesions,” said Dr. Lasala, Professor of Medicine, Washington University School of Medicine in St. Louis. “Outcomes in the simple-use patients in ARRIVE are consistent with results from the Taxus stent cohorts in the TAXUS randomized clinical trial program, indicating that the ARRIVE methodology is very efficient in capturing adverse event outcomes. Overall, then, these results support the long-term performance of the Taxus stent across the broad range of patients studied in these trials and registries.” The pooled analysis included twoyear outcomes for 7,033 patients in the ARRIVE 1 and 2 registries, including those with long lesions, bifurcations, graft stenting, significant calcifications, and multi-vessel stenting. There were no differences in two-year safety rates (all death, Q-wave myocardial infarction [MI], or ARC definite/probable stent thrombosis) between ARRIVE simple-use patients and the clinical trial cohort. Adverse event rates at one year were expectedly higher for expanded-use versus simple-use ARRIVE patients, and included all death (4.2% vs. 2.3%, respectively), all MI (1.8% vs. 1.2%), target lesion revascularization (TLR) (6.2% vs. 3.4%), and ARC stent thrombosis (2.2% vs. 0.9%). However, Taxus stent-related adverse event rates during the second year of follow-up were lower for both expanded-use and simple-use patients than in the first year. Overall rates for Taxus stent-related events in ARRIVE were within expected ranges given the patient complexity. Through two years, medically treated diabetic patients had a higher rate of all death (9.7% vs. 5.1%, p<0.0001) compared to non-diabetic patients but similar rates of TLR (8.1% vs. 7.7%, p=0.63), MI (2.5% vs. 2.2%, p=0.40), and ARC stent thrombosis (3.0% vs. 2.4%, p=0.13). Patients with graft stenting or stenting of bifurcation lesions had significantly higher rates of ARC stent thrombosis and TLR through two years, as expected given the complexity of the lesions treated. The safety and effectiveness of the TAXUS Express Stent has not been established in lesions longer than 28mm, bifurcations, saphenous vein grafts, multi-vessel stenting or diabetics. ■

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Cath Lab Digest - April 2008 Kaiser San Rafael Medical Center Orbital Atherectomy: A New Treatment for Complex Peripheral Arterial Disease Ask the Clinical Instructor: A Q&A Column for Those New to the Cath Lab Contents Clinical Editor’s Corner CEU Education Center The Missing Link in STEMI Interventions — Thrombus Aspiration during Primary Percutaneous Coronary Intervention Predicting Stent Thrombosis Using A Clinical Risk Score Use of a New Guidewire: The Tigerwire Should I Stay or Should I Go? Weighing Options for New Opportunities Navigating Tortuous Coronary Sinus Anatomy Using a Bipolar Lead The National Society of Radiology Practitioner Assistants (NSRPA) Holds 9th Annual Educational Conference For Medical Imaging Physician Extenders and Mid-Level Healthcare Providers Cath Lab & Beyond: A Meeting Update The Ten-Minute Interview with… Dale Hansen RT, CVT Sometimes, You Just Know Twin Circumflex Arteries: A Rare Coronary Artery Anomaly What Do You Think? Meetings Calendar News from the American College of Cardiology (ACC) Scientific Session and the Society of Cardiovascular Angiography & Interventions (SCAI) Annual Scientific Sessions in Partnership with the ACC i2 Summit Clinical & Industry News Cath Laughs Classifieds Advertisers Index

Cath Lab Digest - April 2008

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