[Detection of multivessel lesions after myocardial infarction. Improvement of the predictive value of early exercise stress test by discriminant analysis]. / Détection des lésions multitronculaires après infarctus du myocarde. Amélioration de la valeur prédictive de l'épreuve d'effort précoce à l'aide d'une analyse discriminante.

ABSTRACT

The aim of this study was to assess, by a discriminant analysis, the different parameters of exercise stress testing associated with multivessel disease after uncomplicated myocardial infarction and to determine whether their combination improved the diagnostic value of ST depression alone, the usual diagnostic criterion. One hundred and seventeen out of 240 consecutive pts admitted for acute myocardial infarction between october 1992 and may 1994 underwent early exercise stress testing and coronary angiography 8.5 +/- 3 days and 13 +/- 8 days respectively after infarction. The population was divided into two groups a "study" group (pts recruited between october 1992 and october 1993) for whom a diagnostic equation had been established based on a discriminant analysis, and "a control" group (pts recruited between november 1993 and may 1994) allowing validation of the diagnostic equation. Of the 9 clinical and 14 exercise stress test variables, only 3 remained statistically significant after discriminant analysis in this study group the number of METS achieved (p < 0.0005), maximal ST depression in V5 (p < 0.005) and maximal heart rate (p < 0.01). Using these three parameters, a discriminating equation was established in the study group and then validated in the control group. Using this equation, the percentage of pts correctly identified as having multivessel disease was 75% in the study group and 79% in the control group, whereas ST depression, the most commonly used criterion, only classified 68% of the study group and 60% of the control group correctly. This study confirmed the good tolerance of early maximal exercise stress testing after uncomplicated myo-cardial infarction. The combination of three easily discernable parameters improved the diagnostic performance of the stress test in identifying multivessel disease after myocardial infarction.