EXTRA takes a unique approach to the interpretation of exercise
test results, using a combination of scores rather than a single score. Using
simple clinical and exercise test variables and scores improves the predictive
accuracy of detecting the presence and severity of coronary artery disease
far beyond the use of standard ECG criteria. In addition, the unique approach
appears to be unaffected by disease prevalence, missing data, definition variances
and even by angiographic criterion.
The outcomes are then stratified into low, intermediate and high risk for any coronary artery disease. Given that the patients in the intermediate group would be sent for further testing and would eventually be correctly classified, this approach has a sensitivity and specificity for any CAD of 85% and 92%, respectively, and a sensitivity and specificity for predicting severe CAD of 81% and 91%, respectively. Overall, a predictive accuracy of 88% is obtained by using EXTRA and this scoring strategy. These are results typically seen only with more expensive imaging modalities such as Stress Echo, Thallium/SPECT testing and Electron-Beam CT.
|Test Modality||Any CAD Sensitivity||Any CAD Specificity||Predictive Accuracy|
|Standard Exercise ECG||68%||77%||73%|
|EXTRA + Score Strategy||85%||92%||88%|
This approach effectively limits the usage of these more expensive imaging modalities to one-third of patients and excludes the need for cardiac catheterization in another one-third of the patients. Also, these results could frequently prevent the need for cardiac catheterization.
Sunnyside Biomedical LLC
P.O. Box 1171
Mountain View, CA 94042
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