Recent media reports based on a new study published in the Nov. 27 issue of the New England Journal of Medicine have reported that "noninvasive CT scans cannot replace imaging of coronary artery blockages by conventional invasive angiography."
In response, imaging specialist Juhani Knuuti, spokesman for the European Society of Cardiology (ESC) and past-chair of the ESC Working Group on Nuclear Cardiology and Cardiac CT, issued a statement emphasizing the following points:
The CT imaging techniques have developed very rapidly and during recent years the use of CT to image coronary arteries has been rapidly growing. While it was initially hoped that this noninvasive test could even replace invasive coronary angiography, it has been obvious for a couple of years that this is not the case, according to Knuuti.
The strength of invasive coronary angiography is that the treatment procedures such as dilation of stenosis and stenting can be done in the same session, which is never the case with noninvasive imaging studies, Knuuti noted. However, due to risks of invasive procedures, these tests should be ideally limited to the patients with high likelihood of disease and necessary procedures, he said.
The strength of CT angiography in the previous studies was the very high negative predictive value. For example, when the test result is negative the significant coronary artery disease is very unlikely. Consequently, ESC imaging experts have recommended CT angiography to be at the best in excluding coronary artery disease in the patients with low to moderate pre-test likelihood of disease.
The debated study by JM Miller and colleagues is the first multicentre trial for 64-slice CT angiography. While the results were mainly in agreement with the previous single centre studies and demonstrated good accuracy in general, the negative predictive value was somewhat lower (83%). This raises questions whether the technique is indeed very precise in excluding coronary artery stenoses when applied in clinical routine and in multiple sites, Knuuti noted.
Another issue that was actively discussed, was the radiation risks of the CT scans. It is obvious that all necessary actions are needed to minimize the risks of imaging, including radiation risks, Knuuti said. In the debated study, the radiation doses by CT were 2-3 fold higher than in invasive angiography, but still in moderate level. However, with the current generation of CT scanners, which were not widely available at the time the study was started, the radiation dose is ranging from 3 to 7 mSv, which is actually less than with invasive angiography. Newer techniques are looking at lowering the radiation dose even further, according to Knuuti.
He also pointed out that anatomical imaging, noninvasive or invasive, does not accurately tell whether the detected coronary blockages are causing ischemia and whether the lesions are the cause of the symptoms of the patients. As it is stated clearly also by clinical guidelines, functional ischemia testing is needed to assess whether the coronary stenoses are hemodynamically significant (how much blockage prevents the blood from flowing). This can be done by cardiac nuclear imaging, stress echocardiography, magnetic resonance imaging or invasive flow measurements. Using CT, now also noninvasive imaging of coronary anatomy is possible and it is very likely that this information will be combined with functional imaging findings making finally comprehensive noninvasive evaluation possible.
St. Jude wins CE mark for AnalyST ICD
St. Jude Medical (St. Paul, Minnesota) recently received CE mark approval for its AnalyST implantable cardioverter defibrillator (ICD) with ST Monitoring, calling it "a revolutionary device that not only provides life-saving therapy for dangerously fast heart rhythms, but also continuously monitors electrical changes between heartbeats (called ST segments) to help physicians monitor disease progression."
The company said this new monitoring capability may give physicians earlier and more accurate insight into cardiac problems and may help reduce patient risks. St. Jude also said AnalyST ICD with ST Monitoring is the industry's first device to continuously monitor specific changes in the heart's electrical system which can indicate conditions such as ischemia. It noted that changes in the ST segment also have been linked to events such as heart attacks.
"Learning about these conditions earlier may lead to more timely diagnosis and therapy for patients, and possibly improve patient prognosis," St. Jude said in a statement.
"The AnalyST ICD is the only implantable device that can provide me with ST segment monitoring reports via high-quality, intracardiac electrograms, as well as additional ST segment diagnostic reports," said Christian Hamm, PhD, of the Kerckhoff Klinik (Bad Nauheim, Germany), who implanted the first AnalyST ICD. "This device provides me with new and valuable information about my patients' ST segments that is otherwise not available and helps me deliver better and more timely care for my patients with arrhythmias and coronary artery disease."
With the device's monitoring diagnostic, small changes in ST segment are "continuously and precisely recorded and plotted," St. Jude said, and then retrieved for the physician to review during patient follow-up visits.
CE mark for Amplatzer Cardiac Plug
AGA Medical (Plymouth, Minnesota) received CE-mark approval for its Amplatzer Cardiac Plug (ACP), which provides a minimally invasive solution for closing cardiac structures not involving the septal wall. One such use will be for the non-surgical occlusion of the left atrial appendage.
"The ACP is an important addition to the interventional tools we have for structural heart repair. The design and conformability of the device as well as its ease of deliverability will allow us to effectively occlude challenging anatomy such as the left atrial appendage," said Bernhard Meier, MD, professor and chairman of cardiology at University Hospital (Bern, Switzerland). "Scientific data suggests a strong link between atrial fibrillation and formation of thrombus in the left atrial appendage, which can increase the risk of stroke to 5% per year. Physicians have limited options to minimize stroke risk other than anticoagulants, which are often associated with adverse side effects."
Made of flexible braided Nitinol mesh, the ACP is designed to provide occlusion with full cross-sectional coverage. The ACP self-orients to the cardiac wall, covering the hole of the structure to be occluded. It leverages the proven microscrew technology platform used in all AGA Medical devices to provide physicians with simple, controlled and precise delivery. This allows the ACP to be recaptured and repositioned if necessary, ensuring a customized delivery and fit for each patient's unique anatomic structure.
The company has filed for an Investigational Device Exemption with the FDA for clearance to begin a clinical trial in the U.S. in the first half of 2009.
Sorin Group releases new CRT-D system
Sorin Group (Milan, Italy) reported the market release and first implant of its new-generation Paradym CRT 8750 cardiac resynchronization therapy defibrillator (CRT-D).
The company said that, together with the new Situs BW 28D left ventricle pacing lead and lead delivery system, Paradym CRT forms a completely new CRT system for heart failure patients.
Paradym CRT is designed to allow more flexibility in the management of cardiac resynchronization and anti-tachyarrhythmia therapy in heart failure patients, thanks to its Brady-Tachy Overlap (BTO) feature.
Guidelines for heart failure management recommend exercise training as part of the treatment for HF patients, as it has been shown to reduce mortality and improve quality of life. With BTO, Paradym CRT is able to provide bi-ventricular resynchronization therapy at the elevated heart rates necessary to support patients' exercise.
HF patients often present slow ventricular tachyarrhythmias (slow VT) at the same elevated rates. Paradym CRT is designed to recognize and treat slow VTs without compromise to resynchronization therapy.
"The physical activity of the patient is definitely a key component to take into consideration when treating every heart failure patient," said Christian Butter, MD, head of the cardiology department at Heart Center Brandenburg (Berlin). "Paradym CRT offers my heart failure patients the significant benefit of delivering resynchronization therapy during sustained exercise, while detecting and treating slower ventricular tachycardias without programming constraints."
Butter implanted the first Paradym CRT device in a 38-year-old woman.
Sorin noted that for heart failure patients, it is crucial that life-saving therapies are delivered only when necessary, to avoid a decrease in the patient's quality of life. It said Paradym CRT features the PARAD+ detection algorithm, "whose superior specificity in discriminating ventricular arrhythmias has been clinically proven."
Whenever a shock is needed, Paradym delivers it swiftly with an energy level of up to 37J (42 J stored), the highest available in the market. "This will give maximum assurance to both patients and clinicians in the treatment of life-threatening arrhythmias," Sorin said.
Fred Hrkac, president of the CRM business unit at Sorin, said, "[The] Paradym CRT … device provides patients the highest delivered energy available on the market to date in a small and long-lasting device. With Paradym CRT, patients have the opportunity to exercise, while arrhythmias at all different rates can be accurately treated."
UK patients treated with MitraClip
Percutaneous heart valve device maker Evalve (Menlo Park, California) reported that the first three patients have been treated with the MitraClip system at the University of Hull's Castle Hill Hospital in the UK.
The MitraClip system is the first commercially available device that provides a non-surgical mitral valve repair option for patients suffering from the effects of mitral regurgitation (MR), the most common type of heart valve insufficiency in Europe and the U.S., affecting millions of people worldwide.
Repair with the MitraClip device is performed by physicians in the cath lab. The heart beats normally during the procedure, and thus does not require a heart-lung bypass machine. In addition to improving blood flow through the heart, the procedure may also may relieve symptoms such as fatigue and shortness of breath that can affect patients with significant MR.
The first UK patients were treated by a team led by Farqad Alamgir, MD, consultant cardiologist; Simon Thackray, MD, consultant cardiologist; Raj Nair, MD, cardiology registrar and Andrew Clark, MD, reader and honorary consultant in cardiology.
"This technology is cutting-edge and may transform the way many of our patients receive heart surgery," said Alamgir. "The MitraClip therapy reduces many of the risks and trauma currently associated with open heart surgery. I believe the MitraClip system will not only play a key role for non-surgical MR patients, but should also be considered as a therapy for select surgical candidates."
Evalve received CE-mark approval for the MitraClip system earlier this year and began commercial sales in Europe in September. The company has worked with hospitals across Europe to establish training programs in support of the European roll-out.
The MitraClip system is undergoing clinical evaluation in the U.S. and Canada.
"Suitable patients now have a less invasive therapeutic alternative to surgery for repairing the mitral valve," said President/CEO Ferolyn Powell. "The … treatment of the first series of patients in the UK marks another notable milestone for those suffering from MR. We are pleased with the early acceptance and results of the MitraClip therapy and will continue to work to make the therapy available throughout the European Union."
Evalve is the first portfolio company from the medical device company incubator, The Foundry.
Middle East added to territory for Catania
CeloNova BioSciences (Newnan, Georgia) reported that it has expanded the areas in which it is selling its Catania coronary stent system with NanoThin Polyzene-F, a stent system that has not had any stent thrombosis in clinical studies, according to CeloNova. The Catania system is CE-marked and available throughout Europe and now in some Middle Eastern countries, with "aggressive" worldwide expansion ongoing, according to the company.
CeloNova also reported that it has received regulatory approval to increase the shelf life for the stent from two years to three years.
The Catania Polyzene-F surface treatment is an inorganic polymer that confers superior biocompatibility and lubricity to the substrates it coats. The Polyzene-F treated surface is anti-inflammatory, promotes quick and complete vessel healing, reduces peri-operative and post-procedural platelet activation, and helps to prevent tissue reactions that lead to restenosis.
"After having evaluated the Polyzene-F coating many years ago, it is interesting to see this concept coming back with experimental and initial clinical data quite encouraging toward prevention of stent thrombosis," said Antonio Colombo, MD, director of the cardiac cath lab at Columbus Hospital and chief of invasive cardiology at San Raffaele Hospital, both in Milan, Italy, who recently added the Catania stent to his practice.
The one-year data for the first-in-man study presented at last month's Transcatheter Cardiovascular Therapeutics conference shows that at 12 months, in an unusually complex FIM patient population, the results showed zero percent stent thrombosis (Academic Research Consortium, or ARC-defined), death, myocardial infarction, stroke, or coronary artery bypass graft. Target lesion revascularization was 10.9% (only 3.6% clinically driven, 7.3% non-clinically driven), with a binary restenosis rate of 6.8% (five of 74 lesions analyzed at twelve months). Of note, all patients stopped dual anti-platelet therapy after 30 days, but continued aspirin (100 mg/d) throughout the 12-month period.
The acute angiographic and procedural success rate in the ATLANTA trial was 100%. Independent core laboratories analyzed quantitative coronary angiography and intravascular ultrasound data for all patients immediately after stent implantation and at six-month follow-up. Further analysis of 1,904 cross sections (19,028 struts) by investigators using optimal coherence tomography at baseline and again at six-month follow-up in a subset of 15 randomly selected patients revealed complete endothelialization and 99.5% stent strut coverage.
"The Catania stent, while it is superbly engineered to include the highly developed Polyzene-F, is a simple solution to a complex problem," said Thomas Gordy, president/CEO of CeloNova. "It has no drugs, no thick polymeric coating, no substance to artificially stimulate cell growth, and no additives. And it does not force patients to take dual antiplatelet therapies for months on end, further complicating their lives."
MGuard stent okayed in Israel
In other coronary stent news, InspireMD (Tel Aviv, Israel) reported that its MGuard coronary stent system has been approved for use in Israel by the Israeli Ministry of Health.
The MGuard stent system presents a combination of a coronary stent merged with an embolic protection device. Lifelong embolic protection is achieved by an expandable, flexible fishnet-style, micron-level knit sleeve that wraps the stent.
In addition, MGuard blocks embolic showers and plaque detachment from the arterial wall, blocking debris at the source during and post procedure. The net is designed to diffuse stent pressure on the vessel wall, thereby reducing injury and lowering the likelihood of restenosis.
Since receipt of CE-mark approval in November 2007, the device "has been met with much enthusiasm and celebrated by leading interventional cardiologists worldwide," said InspireMD.
InspireMD marked the launch of MGuard in Israel at this week's ICI '08 meeting in Tel Aviv, where MGuard was demonstrated at the company's booth.
In addition, InspireMD hosted a symposium on "MGuard: A Unique Solution for Managing Embolic Complications in Acute MI and SVG," chaired by noted cardiologists Martin Leon, MD, and Chaim Lotan, MD.
Nicast introduces NovaMesh
Nicast (Lod, Israel) reported the introduction of its NovaMesh for the treatment of ventral hernias at MEDICAedica 2008 in Dusseldorf, Germany, last month. "NovaMesh is the first hernia mesh to exploit the unique properties of electrospun nanofabric. It offers improved resistance to tissue adhesion on the visceral-facing surface and promotes excellent tissue ingrowth on the fascial surface," said CEO Benjamin Eliason.
Nicast will also exhibited the AVflo vascular access graft for hemodialysis, its flagship product which received CE-mark certification in October. AVflo, a self-sealing vascular access graft, offers a prime alternative to current products, as it enables unobstructed blood flow, allows for dialysis within 24 to 48 hours after implantation and self-seals within less than five minutes following withdrawal of the dialysis needles.
It is simple to implant and to suture to blood vessels; the needle punctures and suture holes seal rapidly. AVflo also is strong enough to withstand the pressure of blood flow, yet thin enough for blood flow to be easily felt through it.
Nicast said it is in discussions with distributors from EU and Asian countries regarding first distribution agreements for this device.
"Nicast is one of the few companies with expertise in the use of electrospinning," said Dr. Jacob Dagan, chairman of the board. "The company's extensive product line is built on its many patents and various technology platforms. Other products in development at Nicast include non-metallic stents, a spinal disc device and drug release devices."
Nicast makes implantable devices made of electrospun polymer nanofabrics for a wide range of applications.