The major challenge of post-infarction risk stratification is to differentiate among uncomplicated patients those who are at increased risk of late cardiac events (10-12% 1-year mortality) and those at very low risk (1-2% 1-year mortality). Ultrasound imaging applications to detect exercise-induced left ventricular wall motion abnormalities have gained great relevance In the clinical practice as well as in the research field. The high sensitivity and specificity of detection of exercise-induced left ventricular wall motion abnormalities in coronary artery disease patients have been also used in acute myocardial infarction patients and the results obtained confirm its value in risk stratification. However all the studies were performed before the widespread use of thrombolytic therapy or acute intervention of coronary revascularization. These results cannot be applied to contemporary patterns in the clinical practice where a significant number of patients (20-35%) may have received lyric therapy. In this respect, what should be still demonstrated is if the predictive value of the exercise test carried out in several investigations in the pre-thrombolytic era is still unchanged. In our experience on 348 subjects with acute myocardial infarction (126 undergoing thrombolytic - Group A - and 222 conventional therapy - Group B) we obtained a negative predischarge exercise test in 61.9% of the treated patients and in 52.7% of controls. During a 2.5 ± 2 year follow-up of patients with negative exercise test coronary events (cardiac death, reinfarction, severe angina) were observed in 15.8% of treated patients and in 10.8% of controls. Furthermore, regarding the assessment of the extension of the jeopardized myocardium subserved by the infarct-related coronary artery and its prognostic relevance, the ECG exercise test can hardly identify peri-necrotic ischemia, whereas echocardiographic imaging techniques have a higher sensitivity in identifying the area of this jeopardized myocardium by the worsening or the extension of wall motion abnormalities present at rest. Our results showed a higher percentage of pen-necrotic Ischemia in the thrombolyzed patients (39.6% of positive tests) with respect to controls (16.2% of positive tests). Follow-up data showed a lower rate of coronary events in Group A patients with positive test (20.7 vs 26.6% in Group B); however, in the subgroup with positive test in the region supplied by the infarct-related vessel the event rate was much higher (26.3% in Group A and 11.8% In Group B). Thus, stress echocardiography is recommended for risk stratification after acute myocardial infarction; in thrombolytic-treated patients more attention is due to exercise-induced ischemia in the region supplied by the infarct-related vessel, predictor of a higher rate of coronary events.
|Number of pages||4|
|Publication status||Published - 1996|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Radiology Nuclear Medicine and imaging