A Multivariate Approach for Interpreting Treadmill Exercise Tests in Coronary Artery Disease

To determine the value of a multivariate approach for the analysis of the treadmill exercise tolerance test (ETT), 237 patients referred for evaluation of chest pain who underwent a standard Bruce protocol ETT and coronary arteriography were studied. Predictive value of a positive ETT was 0.78 (43/55) using 1.0--1.9 mm ST segment depression criterion, 0.97 (59/61) using greater than or equal to 2.0 mm ST segment depression. When the 1.0--1.9 mm ST criterion was combined with peak systolic blood pressure-heart rate product (double product) less than or smaller than 23,000, exercise duration less than 6 minutes, and ST depression for greater than 3 minutes into recovery, predictive value improved to 0.89 in 18 patients with any two of the above. Predictive value for multivessel disease was also improved using non-ST criteria. Predictive value of a negative ETT for absence of coronary artery disease was 0.60 (29/48), and was 0.86 (12/14) if double product was greater than or equal to 30,000. Presence of chest pain during ETT did not improve predictive value of any type of test. Digitalis ingestion in 33 patients was not associated with decreased predictive value of a positive test. These data suggest that the predictive value of both positive and negative ETT in a symptomatic population can be improved with a multivariate approach.