Cardiovascular Business - November/December 2008 - (Page 20)

INSIDE IMAGING Views of the heart taken from the apex of the ventricles, to visualize parts of the left- and right-sided chambers. Left, without contrast, right, with contrast. Source: Lantheus Medical Imaging Clinical proof Studies proving the efficacy of echo contrast agents began appearing in 2001. They have demonstrated that up to a third of the images taken without contrast are often inadequate. They have also demonstrated that medical management of patients is significantly improved when contrast agents are used. When patients bypass contrast-enhanced echo, they invariably are referred to nuclear tests, which are more costly. Zoghbi says that the appropriate use of contrast is extremely cost-effective, since the improved accuracy of echocardiographic studies in difficult-to-image patients impacts patient management and decreases downstream utilization of more invasive— and more costly—procedures, such as nuclear scans, transesophageal echocardiography (TEE) or cardiac catheterization. In particular, he cites a study, conducted by Leslee J. Shaw, MD, et al which found that contrast agents were cost-efficient (Ultrasound Con Agents 2001). Yongqi Yong, MD, from Baylor College of Medicine in Houston, and colleagues found that contrast echo was cost-effective compared with TEE, in determining regional and global ventricular function, with a cost saving of 3 percent and 17 percent, respectively (Am J Cardiol 2002;89:711–718). The consensus is, and the evidence suggests that, when the correct diagnosis is made the first time with the help of contrast agents, the hospital saves money, says Main. He also acknowledges serious adverse events with the contrast agents are quite rare in daily practice. Additionally, new data have emerged indicating that side effects occur at a very low level. Main et al conducted a study seeking to assess any mortality difference in patients undergoing echocardiography while hospitalized, with (12,475 cases) and without (6,196 cases) contrast enhancement (Definity) (JACC 2008;51:1704-1706). They found that 0.4 percent of hospitalized patients died within 24 hours of the echo, but found no increased mortality risk associated with Definity, “despite evidence for higher clinical acuity and more co-morbid conditions in patients undergoing contrast studies.” Main says that the 0.4 percent mortality rate is “due to the fact that this patient population is very sick. We suggest that the adverse events, previously attributed to the echo contrast agents, might be pseudo-complications, due to their underlying disease.” Charles A. Herzog, MD, of the echocardiography laboratory at Hennepin County Medical Center in Minneapolis, found that from February 1998 to February 2002, 3,051 patients received Optison with no adverse events recorded. From February 2002 to October 2007, 12,974 received Definity and 20 events were recorded, four of which were serious (JAMA 2008;299(17):2023-2025). The adverse event rate overall was 0.12 percent. In an analysis, Paul Grayburn, MD, from Cardiology Consultants of Texas, said that the four deaths cited by the FDA occurred over a six-year period, in which two million doses were administered, indicating that the fatal event rate was approximately one in 500,000. Grayburn wrote that the rate “is far less than the fatal event rate of a treadmill exercise test (one in 2,500) or a transesophageal echocardiogram (one in 10,000)” (Am J Cardiol 2008;101(6):892-893). A larger multicenter clinical study evaluating more than 4.3 million patients—almost 60,000 of which had contrasts administered—found no difference in crude mortality. However, when the researchers examined the risk-adjusted mortality rates, there was an association between improved survival rates with contrast-enhanced echocardiography studies compared with noncontrast enhanced studies. The study is slated to be published in the December issue of the American Journal of Cardiology. The market drop-off Despite the recent studies and modification of the contraindications, the remaining black-box warning seems to have scared off providers from using the agents. In fact, the use of contrast for echocardiography declined 22 percent in the second quarter of 2008, compared to usage in the same quarter of 2006, according to research from Arlington Medical Resources (AMR), which provides market analysis for the pharmaceutical and diagnostic imaging industries. AMR collected data from a random sampling from several hundred facilities throughout the U.S. and Europe. Analyst Anna Fisher says the role of ultrasound contrast agents continues to be important in the overall echocardiography market because it enhances imaging quality for interpretation. For fear of liabilities, however, many facilities, especially community 20 Cardiovascular Business November/December 2008

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Cardiovascular Business - November/December 2008 Contents First Word Cover Story: Practice Management Software Moves Beyond Bean Counting The Death of CME as We Know It? Clinical Study Digets: Triple-Antiplatelet Therapy; Ex-Vioxx Users Beware Shockwaves Subside from the FDA's Echo Contract Warning Burning Question: Does Laser Heart Therapy for Angina Really Work? Advanced Visualization Adds New Practive Dimension Coronary Calcium Scoring Program Reaps Dividends Interventionalists Get Pumped Up About Mechanical Chest Compression Trials Force Physicians to Re-Examine Oral Anti-Diabetic Drug Protocols News & Views Calendar Reader Resources The ACC Corner

Cardiovascular Business - November/December 2008

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