February 2002: The Latest News In Invasive Cardiology

New Research Points to Key Role of Imaging Test in Reducing Higher Cardiac Event Rates and Improving Outcomes in Patients with Diabetes The results of a new study show that a noninvasive imaging technique, called stress myocardial perfusion imaging (MPI), can help to more accurately detect crucial warning signs of future cardiac events in patients with diabetes. The results of the study show that stress MPI is more accurate in predicting future cardiac events than clinical assessment alone. These findings suggest that the information provided by a stress MPI test may result in earlier intervention and improved patient outcomes for the 16 million Americans with diabetes who are more likely to die from heart disease than any other cause. The effectiveness of stress MPI has been well established in the general population for some time, says Gary V. Heller, MD, PhD, principle investigator of the study and director of the Nuclear Cardiology Laboratory at Hartford Hospital in Hartford, Conn. But now, our research confirms that the use of stress MPI used in combination with clinical indicators can accurately predict the risk of heart disease in patients with diabetes. The clinical implications of these findings are significant given that patients with diabetes are at greater risk for heart disease but tend to be among the most challenging to diagnose. This research trial is a substudy of the Economics of Noninvasive Diagnosis (END) trial and involved 929 patients with diabetes, the largest study of its kind. Patients underwent standard clinical assessment and stress MPI and were evaluated for the occurrence of cardiac death, heart attack, and revascularization (bypass surgery or angioplasty). Key findings include: An abnormal stress MPI result effectively predicted heart attack and cardiac death in patients with diabetes, independent of the clinical assessment. Patients with diabetes and a normal imaging test experienced relatively few heart problems, similar to those without the disease, for up to two years after the test. However, after two years, rates of heart problems began to increase, confirming the accelerated progression of atherosclerosis in patients with diabetes. This led researchers to recommend re-testing of patients with diabetes who have normal Cardiolite® (Kit for the Preparation of Technetium Tc99m Sestamibi for Injection, Bristol-Myers Squibb Medical Imaging, Inc.) test results earlier than patients without diabetes. Stress MPI performed equally well in women and men with diabetes as well as in patients with and without diabetes. For any given degree of ischemia, women with diabetes had a worse prognosis, underscoring the importance of timely diagnosis and aggressive treatment. New Real Time MRI Stress Test A new type of stress test may soon offer doctors a safer and easier way to diagnose heart disease. The new stress test, called fast cine magnetic resonance imaging, or MRI, offers physicians an alternative for diagnosing coronary artery disease in patients who are not good candidates for standard stress tests, such as stress echocardiography. The technique will open a lot of doors, says W. Gregory Hundley, MD, assistant professor of medicine in cardiology and radiology at Wake Forest University School of Medicine and lead author of the study. With this information, doctors will be better able to determine the severity of a patient’s heart disease, and decide on the most appropriate medical management. The fast cine MRI stress test uses a new form of high-speed MRI to view the wall of the heart as it beats. The fast cine MRI is able to capture the heart’s movement at almost the same time the heart is contracting and relaxing, or close to real time. Patients receive dobutamine and are placed in the MRI machine. Dobutamine works like adrenaline, mimicking the effects of exercise on the heart by increasing the heart rate and the speed at which it contracts and relaxes. It also induces cardiac ischemia. With the high-speed imaging, the physician can evaluate the ability of the left ventricular wall to move during physical stress. The fast cine MRI uses the highest speed available to visualize the rapid movements of the heart and obtain a nearly immediate image of the heart in motion. The test is an alternative for patients who aren’t well suited for standard stress echocardiograms, such as obese patients, individuals who have undergone previous cardiothoracic surgery, or who have lung disease. However, the fast cine MRI stress test should not be used in patients with pacemakers, cochlear implants, metal clips, or defibrillators. The MRI stress test takes approximately 35 minutes, says Hundley, who adds that patients he studied tolerated the procedure very well, despite the well-known fears of MRI procedures, which include claustrophobia. The test proved to be an accurate predictor of heart disease. Among patients who had a negative MRI stress test, 97 percent were free of heart disease within the first year of testing. Boston Scientific Receives IDE Approval for Symbiot Covered Stent Trial Boston Scientific Corporation has received IDE (Investigational Device Exemption) approval from the U.S. FDA to begin its SYMBIOT III pivotal trial using the Symbiot Covered Stent System. The randomized clinical trial has been approved for 50 institutions and 700 patients in the United States and Canada. The trial is designed to evaluate the safety and efficacy of the Symbiot Covered Stent for the treatment of saphenous vein graft (SVG) disease. The company expects to enroll the first patients in the trial shortly. The technical and clinical aspects of degenerated vein graft lesions are very different from those found in the native coronary circulation, and managing this disease is one of the most difficult clinical challenges facing interventional cardiologists, said Dr. Martin B. Leon, Lenox Hill Hospital, New York, Principal Investigator for the SYMBIOT III trial. The Symbiot Covered Stent holds great promise to significantly improve outcomes for these patients. The Symbiot Covered Stent, developed exclusively by Boston Scientific, is a laser-cut, self-expanding nitinol stent encased in a thin porous ePTFE polymer membrane. It is the first stent specifically designed to address the two major limitations of treating SVG disease: the risk of plaque embolization during the procedure and poor long-term outcomes. The ePTFE cover and self-expanding deployment are intended to work together to reduce plaque embolization during the stenting procedure and provide a long-term patient benefit by reducing restenosis. Interim results from the Symbiot I and Symbiot II clinical trials suggest that the Symbiot Covered Stent System has the potential to improve clinical outcomes by reducing complications and lowering restenosis rates, according to Boston Scientific. The primary objective of the Symbiot III trial is to demonstrate superiority over conventional stents in reducing restenosis. In addition to initiating this clinical trial in the United States, Boston Scientific is currently filing for a CE Mark and expects to launch the Symbiot Covered Stent System in Europe and other international markets in spring 2002. AngioDynamics to Begin U.S. Marketing of Angiographic Catheter Line AngioDynamics Inc. will begin marketing of its Accu-vu Sizing Angiographic Catheter line in the United States. The Accu-vu line of catheters offers a unique catheter shape called the Omni Flush shape. The sidehole pattern and tip shape of the catheters allow for opacification of the aorta from distal vessels without obstructing the image. The design also minimizes the amount of contrast agent needed for proper imaging during the procedure. The Accu-vu Sizing Catheter incorporates AngioDynamics’ patented angiographic catheter technology. This provides a soft, highly radiopaque catheter tip in combination with a choice of platinum radiopaque marker patterns along the catheter shaft for catheter tip visibility and accuracy of marker placement. These markers are used primarily in preparation for procedures such as aortic aneurysm stent graft (AAA) placement, percutaneous balloon angioplasty, peripherally placed vascular stents or vena cava filters. Study Says Leptin Might be Risk Factor for Heart Disease Leptin, a protein secreted by fat cells, might be an independent risk factor for heart disease in humans. Researchers used frozen blood samples from the 1989 landmark West of Scotland Coronary Prevention Study (WOSCOPS), a prospective trial that showed that pravastatin, a cholesterol-lowering statin drug, could prevent coronary disease in people with no previous history of it. The current research compared 377 men from the original study who had heart attacks or procedures to open clogged arteries during five years of follow-up and 783 controls who remained free of heart disease events. The controls were matched to cases on the basis of age and smoking history. The researchers found that leptin levels in the men with heart disease were 16 percent higher than in controls. When they looked at risk of cardiovascular events, they found a 25 percent increased risk for every 30 percent rise in leptin levels. The researchers report that leptin remained a risk factor independent of body mass index (BMI), a way to determine if someone is overweight or obese. Leptin levels also increased along with levels of C-reactive protein (CRP), a marker for inflammation in the body that is associated with the development of heart disease. However, when the two proteins were studied together, leptin was still a significant marker for heart disease. This is the first evidence that leptin may be an independent risk factor for the development of coronary heart disease, said Dr. Naveed Sattar. Leptin appears to be as strong a predictor as some well-recognized risk factors such as high systolic blood pressure or low levels of high-density lipoprotein (HDL) cholesterol. Leptin has been the subject of scrutiny since the early 1990s, following its discovery. The protein, when given to mice who were genetically predisposed to obesity, caused quick weight loss by regulating appetite. FDA Clears Myocardial Infarction Test Response Biomedical Corporation has received FDA clearance to market its Ramp Reader and Ramp Myoglobin Test for the rapid diagnosis of acute myocardial infarction. The Ramp System consists of a portable fluorescence reader and disposable test cartridges. The system delivers results in less than 15 minutes. The Ramp Reader is designed to quantify antibody-antigen complexes, while the Ramp Myoglobin Test provides a quantitative measurement of myoglobin levels in a whole blood sample. Myoglobin is the first marker to be released into blood following a heart attack so it allows an early screening test. The company says it is also in the late stages of development on tests for troponin I and CK-MB. Each year in the United States, more than six million Americans are admitted to emergency rooms for severe chest pain, according to the American College of Cardiology. Only about 10 percent of those hospitalized suffer a heart attack. The vast majority are eventually diagnosed with strained muscles, bruises or heartburn. The total cost of unnecessary admissions and misdiagnosis is more than $6 billion. Misdiagnosed heart attack cases also account for nearly 25 percent of malpractice claims against emergency room physicians. EECP Improves Angina Class in Coronary Artery Disease Patients A new study has found that enhanced external counterpulsation therapy (EECP) improved the functional angina class of 70 percent of its coronary artery disease patients. Vasomedical Inc.’s EECP therapy involves placing air pressure cuffs around certain places on the legs and inflating them in controlled sequences to increase blood flow to the heart. The treatment is designed to ease the strain on the heart and encourage angiogenesis to form a natural bypass. The therapy is noninvasive, does not require anesthesia and uses 35 one-hour sessions over about two months. EECP is FDA-cleared for use in treating patients with angina pectoris, acute myocardial infarction and cardiogenic shock. The study on the therapy involved 1,957 coronary artery disease patients, including a cohort of 548 patients with a history of congestive heart failure (CHF). The 70 percent of patients who improved also reported an improved quality of life and fewer anginal attacks with the benefits being maintained during a six-month follow-up period. A subgroup analysis of patients with a history of CHF and severe left ventricular dysfunction revealed that they benefited similarly to those patients with less severe left ventricular dysfunction after EECP treatment. CHF occurs when the heart is unable to pump enough blood to meet the body's demands and fails to empty its chambers sufficiently. When this occurs, blood accumulates in the chest and lower limbs. My experience indicates that EECP can markedly improve functionality and exertional symptoms while reducing the chances for emergency room visits and hospitalizations in many patients suffering from ischemic cardiomyopathy and low ejection fractions, said Dr. William E. Lawson, professor of cardiology at the State University of New York. These data are impressive despite the fact that the patients with a history of CHF in this study were older and had a longer and more severe history of coronary artery disease. As expected in this severely ill group, the patients with a history of CHF did experience a greater rate of major adverse cardiovascular events six-months post treatment than the non-CHF group. However, given the improvements in the CHF group in both functional class and in quality of life, it is possible that these patients would have a lower rate of major adverse cardiovascular events compared to the general population of CHF patients with similar severity of diseases. Ongoing studies, including the randomized, multi-center PEECH trial, will tell us just how effective EECP will be as a disease management tool for heart failure patients. Pocket-sized Electrocardiograph Wins FDA Clearance The FDA has cleared the first pocket-sized electrocardiograph (ECG) machine. The PocketView ECG, a Micromedical Industries Ltd. (Labrador, Australia) product, is a miniature version of a standard ECG machine. The device consists of the pocket-sized ECG device, which is a personal digital assistant (PDA) equipped with Windows CE software, and 12 leads that are placed on the patient’s body. The recorded data can be viewed on the device or transmitted via mobile phone or other wireless networks to a computer for viewing. The PocketView ECG is capable of storing numerous ECGs and displaying up to four separate results on the computer screen for simultaneous comparison. To develop the product, Micromedical Industries modified the software used with standard ECG monitors. Medicure Earns Approval for Trial of Cardioprotective Drug The FDA has given Medicure Inc. approval for a Phase II trial that will evaluate MC-1 in high-risk cardiovascular patients undergoing elective angioplasty. MC-1 is a cardioprotective drug in development for reducing damage associated with heart attacks, stroke, and various heart procedures such as angioplasty. The trial is designed to evaluate MC-1’s ability to protect the heart from ischemia and ischemic reperfusion damage in heart disease patients undergoing angioplasty. It will be carried out under the direction of Dr. James E. Tcheng of the Duke University Medical Center. Up to 100 high-risk patients will be scheduled for elective percutaneous coronary intervention at sites in the U.S. and Canada. The primary endpoint of the trial will be infarct size during the procedure as determined by the release of the cardiac enzyme CK-MB over 24 hours following the angioplasty. Signs of myocardial ischemia will be followed over 24 hours by continuous EKG monitoring. The composite clinical endpoint of death, nonfatal myocardial infarct, new or worsening heart failure, or recurrent ischemia will be determined at 30 days after the procedure. heartbase Announces Two Enhancements: Registry Reporting “ Registry Frequencies Plus SPSS Registry Retrievals Mr. Nick Gawrit, heartbase President and Chief Technology Officer, has announced two enhancements to the heartbase clinical database system. The first enhancement is in the area of Registry Reporting and data quality control “ Registry Frequencies. The second, SPSS Registry Retrievals, addresses data mining and reporting with heartbase. With heartbase’s new Registry Frequencies, users are given menu access to automatically generate frequency statistics for the entire STS (Society of Thoracic Surgeons) and ACC (American College of Cardiology) core datasets or individually selected subsets from the user’s production databases. The user enters the date range desired, and the frequency reports for the STS and/or ACC core datasets are generated from their heartbase production databases and displayed. Users are then better able to check registry data for quality on a daily basis and in advance of harvests for the ACC and STS National Registries. With heartbase’s new SPSS Registry Retrievals, users are given menu access to five separate queries that retrieve the entire STS and ACC core datasets from user’s production databases. The user simply enters the date range desired and the STS and/or ACC core datasets are retrieved from their heartbase production database and displayed in SPSS for generating reports and statistical analysis. More specifically, the SPSS Registry Retrievals are: STS Version 2.35 Core dataset ACC Version 2.0 Diagnostic Cath dataset ACC Version 2.0 PCI Procedure dataset. ACC Version 2.0 PCI Procedure & Segment Detail dataset ACC Version 2.0 PCI Procedure, Segment & Equipment dataset Seven Pacemaker and Defibrillator Leads Successfully Removed in One Procedure The Spectranetics Corporation announced that Rod S. Passman, MD, assisted by Erica Englestein, MD, of Northwestern Memorial Hospital in Chicago, Ill., successfully removed two defibrillator leads and five pacemaker leads in one procedure from a 49-year-old man. The tip from one last pacemaker lead was left in place because it was heavily embedded in scar tissue at the apex of the heart. The patient tolerated the procedure well and had no significant complications. Dr. Passman commented, We had initially planned to take four leads out one day, and then remove the rest in a follow-up procedure, but adhesions stuck many of the leads together, making it necessary to remove them all at once. Although the procedure turned out to be lengthy, it was not particularly difficult. Importantly, the patient’s quality of life is improved since he now has received a functioning cardiac rhythm management device, and, as a result of the lead extractions, there is only minimal risk that blood flow though the implant vein will become occluded. $600,000 to be Awarded to Young Investigators The GlaxoSmithKline Research and Education Foundation for Cardiovascular Disease will award up to $600,000 for research via its Competitive Grants Award Program for Young Investigators. Additionally, the Foundation will sponsor a Genomics Educational Workshop examining new research approaches to evolving technologies in cardiology. It will be a 3-year grant program enabling young investigators and advanced cardiovascular disease fellows from all over the world to obtain funding for innovative research. A total of four $50,000 grants will be awarded per year for three years. Winners of the grants will be announced in March 2002. Applications as well as eligibility details for the grant program are available on the Foundation’s website, www.cvfoundation.org. The Genomics Educational Workshop, which will be held in June 2002, will provide participants with up-to-date techniques to research approaches related to evolving technologies in cardiology. The workshop, to be held in Philadelphia, is offered free of charge to members of the medical community. Attendees will assume their own travel and lodging expenses. The Foundation will sponsor the travel and hotel costs for twenty young investigators (fellows or junior faculty) nominated by their mentors and selected on a merit basis by an independent panel of foundation Advisory Board members. Atherogenics Initiates Phase IIb Clinical Trial of AGI-1067 in Restenosis And Atherosclerosis AtheroGenics, Inc. is initiating the Phase IIb clinical trial of its proprietary v-protectant drug, AGI-1067, for the treatment of restenosis and atherosclerosis. This clinical trial, the Canadian Antioxidant Restenosis Trial-2 (CART-2), will continue to explore the drug's positive effect on reducing restenosis by extending the duration of dosing, and will further investigate the apparent impact of AGI-1067 on the reversal of atherosclerosis, as revealed in a post-study analysis of the CART-1 data. Principal investigator Jean-Claude Tardif, MD, of the Montreal Heart Institute, said, While AGI-1067 was effective in reducing restenosis in the CART-1 trial with only six weeks of dosing, our hypothesis is that this positive effect can be substantially enhanced by a longer course of therapy. In addition, the reversal of atherosclerotic progression will be of significant focus, as it represents a potentially groundbreaking therapy where no comparable treatment exists. The Phase IIb study will enroll 500 patients in approximately 24 clinical sites, and feature a 12-month-long dosing regimen of AGI-1067 at 280mg. As the CART-1 trial featured two-week pre-procedure dosing, the new trial will also examine the need, if any, for pre-dosing. Anticoagulant Safe in Trial on PTCA Patients Corvas International’s anticoagulant rNAPc2 appeared safe and well-tolerated in Phase IIa clinical trial on patients who underwent percutaneous transluminal coronary angioplasty (PTCA) and suffer from coronary artery disease such as unstable angina. The rNAPc2 protein was originally derived from blood-feeding hookworms, and is currently manufactured as a recombinant protein for clinical use. The anticoagulant effect of rNAPc2 results from its ability to block the Factor VIIa/Tissue Factor protease complex, which initiates the first step in the cascade of biochemical events resulting in the formation of blood clots (thrombosis). The data from the trial also showed that rNAPc2 effectively suppressed the formation of thrombin. The incidence of major bleeding was low in rNAPc2-treated patients and was not dependent on the administered dose of rNAPc2. An increase in minor bleeding was observed in only the highest dose group. The Phase IIa trial was a dose-escalation study conducted in 156 patients with stable coronary artery disease undergoing elective PTCA. Each of the five treatment cohorts received either standard therapy with unfractionated heparin and aspirin (placebo) or standard therapy plus rNAPc2 administered as a single subcutaneous injection prior to the PTCA procedure. Many of the patients also received the anti-platelet agent clopidogrel and to a lesser extent glycoprotein IIb/IIIa platelet receptor antagonists. About half the patients underwent coronary stent placement. Photogen Announces Imaging Technology Platform in Cardiovascular Indications Photogen Technologies announced positive results of pre-clinical imaging studies for its proprietary agent PH-50 in cardiovascular imaging indications. The data also yielded positive results for imaging of other organs, such as the liver. In an animal study conducted at Stanford University, Department of Radiology, PH-50 was investigated for coronary, cardiac, great vessel and renal arterial CT (computed tomography) angiography in normal adult New Zealand white rabbits following bolus or slow intravenous infusion. These imaging experiments have shown that PH-50 stays within the vascular system for at least 20 minutes with little diffusion outside the vascular system, suggesting potential for use as both a perfusion as well as a blood pool agent. The properties of intravenous administered PH-50 will permit imaging of the entire vascular system free of flow and mixing artifacts while using conventional and helical CT technologies, commented Dr. Francis G. Blankenberg, Associate Professor of Radiology, the principal investigator of the study. We will also address whether this compound can be used to image early soft non-calcified plaques in coronary arteries, a marker of vulnerable disease prone to rupture and cause sudden death. These high risk lesions cannot be reliably detected with current CT contrast media. PH-50 shows promise as an intravenous and intra-arterial agent for conventional and CT angiography to address the needs for early detection of coronary artery disease and other diseases affecting the body's arteries. The use of PH-50 does not require catheterization, leading to a significant savings in time and physician participation, and may provide detail of the vasculature previously unavailable. The pharmacokinetic properties of PH-50 relative to existing ionic and nonionic intravenous contrast agents suggest potential advantages for clinical cardiovascular and general CT imaging applications. Massachusetts General Hospital Agrees to Commence Animal Studies of Magna-Lab’s New Intra-vascular MRI Catheter Coil Massachusetts General Hospital (MGH) has agreed to commence an animal study of the Magna-Lab Inc.’s intra-vascular MRI catheter coil. The purpose of the study is to further demonstrate the benefits of using an intra-vascular MRI catheter coil to obtain in vivo, high-resolution MR images of the coronary vessel walls. The project will begin immediately, with first imaging expected within the next few weeks. The study is expected to continue for approximately four months. The intra-vascular MRI catheter coil is an intra-arterial receiver coil that is designed for use in conjunction with MRI technology to facilitate the capture of high-resolution MR images to provide a diagnostic view of the fine structures of the arterial wall and various components of atherosclerotic plaque. The product is threaded through a catheter and guidewire to the site of the atherosclerotic blockage. The images obtained through the use of the intra-vascular MRI catheter coil are intended to assist in the treatment of coronary artery disease by permitting the physician to assess the morphology and the chemistry of the atherosclerotic plaque. FDA OKs Continued Study of Spectranetics Excimer Laser The FDA has decided to allow The Spectranetics Corp. to continue its Peripheral Excimer Laser Angioplasty (PELA) study without randomizing patients. The CVX-300 excimer laser is the only system with FDA approval for multiple cardiovascular procedures, including coronary angioplasty and the removal of problematic pacemaker and defibrillator leads. By conducting PELA, Spectranetics is attempting to get FDA approval for the device as a treatment for main thigh artery occlusions. The study extension for PELA allows the excimer laser to be used on 120 additional total main thigh artery occlusion patients at 21 sites. Patients enrolled in the trail will have occlusions at least 10 cm long. The company says the device is on track to gain FDA approval to treat total main thigh artery occlusion by 2003. Joseph A. Largey, president and CEO of Spectranetics, said, PELA III is a registry, so the doctors involved can treat every indicated patient with our laser without randomizing half to a non-laser modality. All PELA patients have pain walking, and some have pain resting, both of which significantly impair their quality of life. With this study extension, we can assist more patients while continuing to work with a small group of doctors to establish laser treatment as the ˜gold standard’ for treating long blockages in the superficial femoral artery of the thigh. Multi-Modality Reporting from a Single Workstation ComView’s new ViewStar multi-modality workstation with integrated report generation provides physicians with a tool for diagnosing and documenting their procedures from any location on the network, regardless of modality. Designed as departmental solution, the workstation determines the level of privileges for each user and adjusts the available options for generating, signing, distributing and reviewing images and reports of patients. Additional administrative tools are available for billing codes, technician assessment and data harvesting. The optional dual monitor configuration allows user full access to diagnostic images while generating or reviewing reports on a separate screen. This is a key feature for maximizing throughput especially in the ultrasound arena. The new features and functions of the ViewStar workstation, in conjunction with the broad range of acquisition, archive and review capabilities of the View product line, provide facilities a single vendor solution for meeting their departmental needs. The ViewStar multi-modality workstation will be on display at the upcoming ACC. ComView’s booth is # 4459.

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