Over the past three years, C-reactive protein (CRP) assays have been tested in a series of large-scale, prospective clinical studies which have demonstrated the value of CRP as a marker in predicting risk of future heart attack, stroke and peripheral vascular disease in otherwise healthy men and women.
In 1997, it was reported that CRP levels were elevated at baseline among apparently healthy individuals who subsequently suffered first-ever heart attacks. Men in the highest CRP quartile had three times the risk of myocardial infarction, two times the risk of ischemic stroke and four times the risk of developing severe peripheral artery disease as compared to men in the lowest quartile. Interestingly, most of the beneficial effects of aspirin were noted in patients with the highest CRP levels.
A recently published study on more than 28,000 healthy postmenopausal women came to a similar conclusion. The study at Harvard Medical School and Brigham and Women's Hospital (both Boston, Massachusetts) found that of 12 different markers measured, high-sensitivity CRP was the most significant indicator of future cardiovascular events, with a relative risk of 4.4 for the highest quartile as compared to the lowest quartile.
As a result, several manufacturers have developed high-sensitivity CRP assays. Orion Diagnostica's (Espoo, Finland) new Ultrasensitive CRP kit can be used with most clinical chemistry analyzers and provides reliable measurement of low levels of CRP in the range of 0.25-10.0 mg/l. The Behring Diagnostics division of Dade Behring (Liederbach, Germany) has developed the N High Sensitivity CRP assay, which uses latex-enhanced immunonephelometry, measuring CRP levels down to 0.175 mg/l. This assay was used in the Harvard Medical School/ Brigham and Women's Hospital study.
Randox Laboratories (Crumlin, Northern Ireland) has recently launched a line of ultrasensitive CRP kits developed for use on a range of automated analyzers and with a detection level claimed down to 0.1 mg/l.
An ELISA technology assay on microtitration plates has been developed by Immundiagnostik (Bensheim, Germany) using double antibody detection and peroxidase labeling. No cross-reactivity is shown against albumin, lysozyme, alpha-1 antitrypsin or other acute phase proteins and the company claims a detection limit down to 0.5 ng/ml.
Philips' HeartCare program
Philips Medical Systems (Best, the Netherlands) has grouped together in the HeartCare unified program the company's portfolio of cardiovascular imaging modalities, connectivity solutions, and support services.
"HeartCare offers an openness that our competitors do not," said Jacques Coumans, chairman of Philips' HeartCare team. "Our philosophy is one that is designed to enable integration with legacy systems and other vendors' equipment, giving cardiologists functionality now while accommodating their vision for the future."
HeartCare includes Philips' new Gyroscan Intera CV magnetic resonance system, which makes possible a one-stop cardiac MR exam lasting around one hour as compared to traditional cardiovascular diagnosis, which could involve ultrasound, nuclear medicine, and cardiac catheterization studies taking several days of scheduling and costing far more. Vectorcardiogram triggering is claimed by Philips to separate true ECG from distortion caused by the magnetic field and RF effects, raising accuracy to almost 100%. The system's MotionTrak technology allows patients to breathe freely during examination, a positive advantage for those patients chronically short of breath.
The Inturis Suite is a fully open networking solution, and when connected to EasyWeb, authorized users can view images anywhere via the Internet.
Heart failure prognosis assay
Immunoreactive adrenomedullin plasma levels were significantly increased in 117 chronic heart failure patients, according to Professor Komajda and colleagues at the Hopital Pitie-Salpetriere (Paris). Adrenomedullin is an endogenous peptide with strong vasodilating and natriuretic properties and could be a good candidate for a prognostic indicator in patients with chronic heart failure. The study found that patients with adverse cardiac outcomes tended to have higher adrenomedullin levels than patients who survived event-free.
Ambulatory blood pressure monitoring
Three new ambulatory blood pressure monitors each feature rechargeable batteries and measurement of systolic, diastolic and mean arterial pressure. The Physio-port from Medlab (Karlsruhe, Germany) can be worn for up to 36 hours, during which measurements are made every 15 to 30 minutes. For patient comfort an integrated real-time clock automatically extends measurement intervals during the night.
The Mapa 33 from Biomedical Systems (Brussels, Belgium) is easily programmable to set measurement intervals at 5 to 90 minutes, with automatic inflation by micropump. With optimal Mapasav Plus software, measurement data can be downloaded to produce trends, histograms, hourly graphs and statistics.
Aspel (Zabierzow, Poland) has developed a 24-hour ambulatory blood pressure monitor, the HolCard CR-05, which is battery-powered and uses oscillometric measurement, as do the two other recorders. The CR-05 measures cardiac rhythm as well as systolic, diastolic, and average blood pressures.
Radiation therapy competition heats up
Novoste (Norcross, Georgia) was the first company to market an intracoronary radiation device, BetaCath, in Europe over a year ago, using beta-radiation, which can be shielded more readily than gamma.
Guidant (Indianapolis, Indiana) CE-marked its beta-radiation system in May, with the Galileo intravascular radiotherapy now available in most European countries for treating de novo lesions and restenotic lesions following angioplasty. Guidant plans to expand the device's indication to include in-stent restenosis, with a 310-patient trial already under way in the U.S.
Cordis (Miami Lakes, Florida) has now joined the fray, with CE-marking completed for the Checkmate intravascular gamma radiation delivery system for treating in-stent restenosis. Checkmate, which uses a catheter-based, iridium-192 gamma-emitting ribbon, is the first device in Europe that uses gamma radiation to treat restenosis, Cordis said.
Aortic graft trial
Boston Scientific (Natick, Massachusetts) hopes to soon complete patient recruitment for a European clinical trial of its third-generation Vanguard III endovascular aortic graft in the repair of abdominal aortic aneurysms.
The Vanguard III graft incorporates modifications that address durability and risks of kinking as the aneurysm morphology changes. The trial, which will be at 11 centers in Europe, is planned to include 70 patients. If the trial is successful, Boston Scientific plans to launch the device in main European markets later this year.
Bioprosthetic heart valves favored in UK
Latest figures from the UK heart valve registry show that almost 2,000 of the 5,600 valves implanted in 1997 were bioprosthetic, rather than mechanical.
In 1994, only 27% of heart valve replacements were bioprosthetic, compared to 35% in 1997. According to the register, there is little difference in comparative re-operation rates between the two valve groups, with overall replacement levels below 3%.
Arrow launches CO monitor in Europe
The HemoSonic 100 cardiac output (CO) monitor from Arrow International (Reading, Pennsylvania and Houten, Netherlands) incorporates a pulsed Doppler transducer and an M-mode echography transducer to provide between them accurate aortic blood flow (ABF) data.
Mounted in a single transoesophageal probe, the monitor provides continuous real-time hemodynamic monitoring in a noninvasive manner. The system measures the descending flow in the thoracic aorta and it "does so extremely accurately, with precisions in the order of a few percent, which is unheard of. It is significantly more important than the gold standard, the Swan-Ganz catheter," said Dr. Jean Luc Boulnois, a co-developer of the device.