"Multislice CT coronary angiography is more cost-effective than any other traditional test up to a (pretest) likelihood of 60% (for coronary artery disease)," said Dr. Marc Dewey from the department of radiology at Charité Medical School, Humboldt-University Berlin in Germany. "After 60%, conventional coronary angiography is the most effective approach."
The research team compared the cost-effectiveness of recent noninvasive imaging approaches to the diagnosis of coronary artery disease (CAD) with those of the traditional diagnostic modalities such as conventional coronary angiography, exercise echocardiography (ECG), and dobutamine stress ECG.
The scientists created a decision tree model that compared three imaging approaches to CAD diagnosis -- CT coronary angiography (CTCA), calcium scoring utilizing electron beam CT (EBCT), and dobutamine stress MRI -- with the three traditional diagnostic modalities.
Patients were given a test to determine likelihood of CAD by assessing risk factors for the disease prior to undergoing a diagnostic exam. This pretest allowed the group to stratify the study cohort by likelihood for CAD expressed as a percentage from 0% to 100%.
According to Dewey, cost-effectiveness was defined as direct and indirect costs per correctly identified diseased patient. For patients with a pretest likelihood of CAD from 10% to 50%, CTCA was the most cost-effective approach with costs per correctly identified CAD patient of 4,435 euros ($5,825.43 U.S.) for the patients presenting with a 10% likelihood of CAD to 1,469 euros ($1,929.42) for the group assessed with a 50% pretest likelihood for CAD.
EBCT trumped traditional diagnostic modalities in cost-effectiveness only for those patients falling into a pretest likelihood range of 30% to 40% for CAD; however, it was not as cost-effective as CTCA for the same cohort with costs ranging from 2,345 euros ($3,079.56) for the 30% group to 1,897 euros ($2,491.61) for the patients with a 40% likelihood of CAD, according to the researchers.
"MRI was not cost-effective for any pretest likelihood," Dewey stated.
Conventional coronary angiography was far and away the most cost-effective diagnostic method for those patients presenting with pretest likelihood of at least 70% for CAD at a cost of 1,153 euros ($1,514.60) to a price of 807 euros ($1,059.95) for those patients who showed a 100% pretest likelihood for CAD.
Dewey noted that a sensitivity analysis conducted by the researchers revealed no significant changes, which he said demonstrated the robustness of the conclusions.
The break point on the cost-effectiveness for the utilization of CTCA compared with conventional coronary angiography was determined to be those patients whose pretest assessment for CAD was 60% or less, while those patients who scored at a 60% or higher likelihood of CAD in their pretest were most cost-effectively handled in a traditional coronary catheterization lab, according to the researchers.
"Although this is only a decision-tree model -- and no patients were sent through this -- nevertheless, these results indicate the cost savings that can be achieved with CTCA," Dewey said.
By Jonathan S. Batchelor
AuntMinnie.com staff writer
November 27, 2006
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