By JOHN BROSKY
CD&D European Editor
and Staff Reports
A 120-patient study conducted at University Hospital Zurich (Zurich, Switzerland) has found that a novel non-invasive step-and-shoot (SAS) mode for the diagnosis of coronary artery stenosis provides highly accurate results compared to the conventional clinical practice requiring invasive coronary angiography while significantly reducing radiation exposure to patients.
The results of the study were published in the June issue of Heart, the journal of the British Cardiovascular Society (London).
The single-center study marks the first clinical trial of the Somatom Definition from Siemens Healthcare (Erlangen, Germany), equipped with two X-ray tubes and support software capable of characterizing tissue and their densities.
The study, "Low-Dose CT Coronary Angiography in the Step-and-Shoot Mode" found the SAS mode successful for all 120 patients with 100% sensitivity, 93% specificity, 94% positive predictive value (PPV) and 100% negative predictive value for the diagnosis of significant stenosis.
Significantly, the dual-source computed tomography (DSCT) uses a greatly reduced radiation dose and also reduces the life-threatening complications associated with invasive coronary angiography.
The primary end point for the study was reduction of radiation doses a goal made possible with new algorithms introduced by Siemens with the Adaptive Cardio Sequence (ASC) software coupled with the two-step image acquisition.
The ASC monitors the heart frequency of patients adjusts the recording window, responding, for example, to arrhythmia by postponing the recording phase to avoid image errors due to the sudden movement.
The resulting images were of "excellent diagnostic quality in patients with stable heart rates up to 70 bpm," according to Hatem Alkadhi, MD, the specialist who led the research team.
Alkadhi said, "The dosage reduction achieved in comparison to previous CT angiography is also remarkable."
He said the effective dose was 2.5 millisievert (mSv), on average, where a normal average effective dose for heart scans is between 9 and 21 mSv.
Dr. Sami Atiya, chief executive for computed tomography at Siemens Healthcare, said the innovations for dose reduction, in conjunction with improved diagnostic image quality, are central to Siemens' approach to a market estimated at $5 billion in products sales for the U.S alone.
The introduction of 64-slice CT technology rapidly emerged in recent years as a promising tool for the clinical assessment of many cardiac conditions.
A CT scan is considered essential for identifying or ruling out hemorrhagic strokes with image acquisition and interpretation required within an hour of a patient arriving at a hospital.
Earlier this year, clinicians at the Erasmus Medical Center (Rotterdam, the Netherlands) noted several scanner generations have been introduced leading to progressive improvements in the detection of coronary artery stenosis.
The increasingly powerful post-processing software allows even high-resolution imaging free of artifacts winning widespread acceptance and demand despite a lack of clinical trials, they note.
Multidetector CT provides an even more robust and reliable non-invasive tool to assess cardiac pathology, clinicians with the British Institute of Radiology saying that as the equipment becomes increasingly available these scanners potentially can play a significant role in the assessment of coronary syndrome in the emergency setting.
Arctic Front in 3 countries
CryoCath Technologies (Montreal), a maker of cryotherapy products to treat cardiac arrhythmias, has introduced its Arctic Front device in Italy, Belgium and Spain.
Arctic Front, the company's lead product for the treatment of paroxysmal atrial fibrillation (PAF), is a cryoablation balloon catheter that allows physicians to isolate all four pulmonary veins for the treatment of PAF (see story, page 6).
"The introduction of Arctic Front in Italy, Belgium and Spain provides us with an exciting opportunity to deliver the benefits of our breakthrough therapy to a larger patient population," said Jan Keltjens, president/CEO of CryoCath. "By expanding our already strong presence in Europe, we are continuing to drive the adoption of [the] Arctic Front system worldwide."
Claudio Tondo, MD, chief of the cardiology division and director of the Cardiac Arrhythmia and Heart Failure Research Institute at San Camillo-Forlanini Hospital (Rome), performed the first procedures with Arctic Front in Italy on June 9.
Tondo said, "The cryo technology represents an effective alternative to radio frequency energy for safety reasons, prompting the extension of the ablative treatment to a larger population of patients suffering from PAF."
The first Arctic Front procedures in Belgium were performed in May by Pedro Brugada, MD, head of the heart rhythm management center and Gian Battista Chierchia, MD, director of the atrial fibrillation and pacing program at UZ Brussel-Vrije Universiteit Brussel.
"We see great promise in the procedural simplicity of the Arctic Front System. The cryoballoon's innovative shape facilitates anatomical placement in the atrium at the ostium of the targeted pulmonary vein," said Brugada.
Julian Villacastin, MD, and his team at Hospital Clinico San Carlos (Madrid, Spain) first used Arctic Front on June 24. The two patients treated to date have had successful outcomes and no safety concerns have been reported.
Britain's heart health 9th in Europe
Britain's provision of heart health care ranks 9th out of 29 European countries, according to the inaugural Euro Consumer Heart Index launched in Brussels.
The new Heart Index compares how consumer-friendly care systems are around Europe. In five categories, covering 28 performance indicators, the UK score placed it in a second tier, some way behind the top-performing countries.
"Heart disease management is actually one of the stronger points of British healthcare services, if one compares their score in the Heart Index to their overall performance in the last European Health Consumer Indexi," said Dr. Arne Björnberg, research director for the Heart Index. "Having the strictest anti-tobacco measures in Europe [is] a good start. If these were complemented with improved patient choice and more rapid access to relevant care, the results could be even better."
What more could be done in the UK?
"To further improve UK cardiac care delivery requires work at both ends of the scale. The introduction of a national screening program to improve prevention is but there is also a need for post-hospital rehabilitation and ensuring that quality is measured, not only targeted," said Johan Hjertqvist, president of the Health Consumer Powerhouse, analyzing the Index implications for the UK.
The Index provides a ranking of European cardiovascular healthcare systems across five key areas to the consumer: Information, Consumer rights and choice; Access; Prevention; Procedures; and Outcomes. The Index is constructed from public statistics and independent research. The producer of the European Consumer Heart Index is the Health Consumer Powerhouse (HCP), providers of analysis and information in healthcare. As with all the HCP's indexes it takes a consumer-centric position. The Heart Index was produced with the help of an unrestricted grant from Pfizer (New York).
Japan OKs Reveal DX
Medtronic (Minneapolis) reported that it has received Japanese regulatory approval for the Reveal DX Insertable Cardiac Monitor (ICM). The device has been designated by the Japanese government as a high-priority medical device, and the company says it is the first insertable cardiac monitor to be introduced in Japan.
The Reveal DX ICM provides insight into syncope, unexplained fainting episodes. Syncope is difficult to diagnose as episodes are often too infrequent and unpredictable for detection with conventional monitoring techniques such as ECG Holter monitors or external loop recorders. These tests are limited to 24 hours and one month, respectively; combined with the constraints placed on the patient's daily life and the limited likelihood of an event occurring during the monitoring period, the testing may fail to determine the cause of the episodes, according to Medtronic.
Causes of syncope can be heart rhythm disturbances or abnormalities in the structure of the heart. Syncope can lead to serious injury or can be a precursor to sudden cardiac death. Roughly 1.5 million people worldwide suffer from unexplained syncope. In almost 10% of patients, syncope has a cardiac cause.
Inserted just under the skin of the chest area, Medtronic said the Reveal DX ICM is about the size of a memory stick and is capable of monitoring patients for up to three years, allowing for long-term, continuous cardiac monitoring. Records of arrhythmias are automatically recorded and saved, and patients may prompt the device to record any events at any time. If the patient experiences a syncopal episode, the information collected by the device may help the physician determine if the episode is attributable to an arrhythmia.
Since no similar device has been available in Japan, the Ministry of Health, Labor and Welfare designated the Reveal DX as "high priority" for approval in Japan. The device was subject to a fast-track evaluation by the Japanese government, and received regulatory approval this month.
Medtronic Japan will begin marketing the Reveal DX ICM once it has attained reimbursement approval for the device. The company will partner with Asahi Kasei for exclusive sales distribution rights for the device in Japan; Medtronic Japan will serve as the device's designated marketing authorization holder.
The Reveal DX ICM is commercially available in the U.S., Western Europe and Canada.
RapidBlue gets CE mark, UL certification
Cardium Therapeutics (San Diego) and its operating unit, InnerCool Therapies, reported that InnerCool's RapidBlue endovascular temperature modulation system conforms to CE-mark requirements for use in inducing, maintaining and reversing mild hypothermia in a variety of clinical indications.
The approved indications include cardiac arrest, neurosurgery, fever, cardiovascular re-warming, trauma re-warming, plus potential additional applications including acute ischemic stroke and myocardial infarction.
The RapidBlue System is a thermal regulating system designed to manage and control patient body temperature. The system automatically cools or warms patients, as necessary, to maintain desired body temperature. It provides rapid or gradual temperature control for all patient sizes and its closed-loop, catheter-based system modulates body temperature without fluid introduction or exchange by circulating cool or warm saline within the interior of the catheter.
The company plans to begin selling the system in Europe and other countries that recognize CE-mark certification in the next quarter.
The RapidBlue System is under review for FDA 510(k) clearance.
"We believe our RapidBlue System is truly the most dynamic and best-in-class temperature modulation system on the market, and receiving CE-mark and UL [Underwriters Laboratories] certification demonstrates that the company has established and operates a world-class quality system," said Chairman/CEO Christopher Reinhard. "This is the first UL global certification for an endovascular thermal regulating system and further confirms the technology leadership position that InnerCool is establishing with the RapidBlue System."
Advances in artificial veins/arteries
Researchers in London say they have taken a "major step" in making the use of artificial veins and arteries in coronary bypass grafts a reality. In a study published in the June issue of The FASEB Journal, the team describes how it developed the artificial graft tissue by combining man-made materials with human cells to make it elastic and durable, and so it can attach to host tissue.
"This advance could be a medical breakthrough that saves millions of lives around the world," said Gerald Weissmann, MD, editor-in-chief of The FASEB Journal. "Even more tantalizing is the successful fusing of living cells to nonliving substances that actually heal by forming a stronger bond to each other and to host tissue once put in use."
This, he said, "might even be called a start toward 'cyborg engineering.'"
"The notion that any body part could be engineered in a lab, attach to existing tissue 'naturally,' and grow stronger as it is being used is something thought completely impossible just 20 years ago," Weissmann said, adding that "it is only a matter of time before human tissues can be engineered to be at least as good as the originals, and this study moves us toward that reality."
In the journal report, scientists describe how they took an elastic scaffold the material that gives the artificial graft its shape of compliant polycarbonate urea urethane and incorporated human vascular smooth muscle cells and epithelial cells from umbilical cords.
They then took the artificial grafts and simulated blood flow in the laboratory to test their durability. They found that as the pulsing fluid flow slowly increased, the artificial graft's performance actually improved. The researchers hypothesize that this improvement is because the movement of fluid through the graft stimulates the smooth muscle and epithelial cells to release proteins that strengthen their ability to attach to the elastic scaffold and other tissues.
The report said coronary artery bypass grafting could benefit from such an approach, since current procedures are limited by the availability of healthy veins or arteries, as well as the patients' ability to survive both the vein-harvesting and artery-grafting aspects of the procedure.
HydroSteer wires okayed
St. Jude Medical (St. Paul, Minnesota) reported CE-mark approval and the European launch of its line of HydroSteer hydrophilic-coated nitinol guide wires.
The HydroSteer line of guide wires features a lubricious hydrophilic coating which becomes slippery when wet, thereby reducing friction and enabling physicians to more easily maneuver the wires through the patient's vessels.
The line includes a wide variety of sizes, lengths and configurations.
St. Jude said the HydroSteer family is designed to provide physicians with more control of the guide wire's tip, "allowing the physician optimal placement of the subsequent procedural tools." It said each wire in the HydroSteer line provides "excellent steerability to help physicians navigate challenging vascular structures."
Guide wires are used to gain access in a variety of cardiovascular procedures. They are used to help guide and steer a catheter (a flexible tube) through the vessels to deliver treatments, such as stents, which open blockages and restore blood flow to the heart or other parts of the body.
The company said a radiopaque polymer jacket on the wire's nitinol (nickel-titanium alloy) core enhances the physician's ability to visualize the wire's location in the vessel. The nitinol core resists kinking while providing the flexibility physicians need to advance the wire through the vasculature, it said.
In addition, a torque device enhances steerability by aiding directional control. The torque device also has received CE-mark approval and is available for separate purchase.
"With the introduction of HydroSteer, the recent launch of the TigerWire guide wire and the availability of our existing GuideRight guide wire line, physicians now may choose from a full complement of St. Jude Medical guide wires used in interventional and diagnostic procedures," said Denis Gestin, president of St. Jude's International Division. "These products reflect our commitment to providing physicians with medical devices that help them control risks and attain the best patient outcomes."