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Postinfarction stress testing and one year outcome of stable patients after myocardial infarction treated with
1Herzzentrum Ludwigshafen, Department of Cardiology, Ludwigshafen, Germany.
Insights
Early stress testing using 99mTc perfusion scintigraphy and stress-echocardiography can predict cardiac events in myocardial infarction (MI) survivors. Bicycle ergometry and coronary angiography showed limited predictive value in this patient group.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Echocardiography
Background:
- Survivors of acute myocardial infarction (MI) treated with thrombolytics require early risk stratification.
- Identifying high-risk patients is crucial for guiding post-MI management and preventing adverse cardiac events.
Purpose of the Study:
- To evaluate the predictive capability of early postinfarction stress testing in survivors of uncomplicated MI who received thrombolytic therapy.
- To determine the association between noninvasive stress testing methods and subsequent cardiac events.
Main Methods:
- 102 clinically stable survivors of uncomplicated transmural MI treated with thrombolytics underwent cycle ergometry, 99mTc perfusion scintigraphy, and dobutamine stress-echocardiography within three weeks post-MI.
- Coronary angiography assessed coronary artery disease (CAD) extent and left ventricular ejection fraction (LVEF).
- A one-year follow-up evaluated cardiac events including unstable angina, reinfarction, percutaneous transluminal coronary angioplasty (PTCA), bypass surgery, and death.
Main Results:
- 30 patients experienced 34 cardiac events within one year, with two-thirds being revascularization procedures (PTCA/bypass surgery).
- 99mTc perfusion scintigraphy (p < 0.006) and stress-echocardiography (p < 0.01) were significantly associated with future cardiac events.
- Cycle ergometry parameters and coronary angiography variables did not predict increased risk of cardiac events.
Conclusions:
- Early noninvasive risk assessment is essential for identifying high-risk patients among stable, early post-MI survivors treated with thrombolytics.
- 99mTc perfusion scintigraphy and stress-echocardiography effectively identify patients requiring revascularization.
- Bicycle ergometry provides limited prognostic value within the first year after acute MI.
Objective:
The purpose of our study was to evaluate the predictive power of early postinfarction stress testing in survivors of uncomplicated MI treated with thrombolytics.
Methods:
The study population consisted of 102 consecutive, thrombolyzed survivors (56 +/- 11 years) of acute, transmural myocardial infarction with uncomplicated postinfarction course. All patients were clinically stable in the postinfarction period and underwent cycle ergometry, 99mTc perfusion scintigraphy and dobutamine stress-echocardiography within three weeks after the acute event. Coronary angiography was used to determine the extent of CAD, LV ejection fraction (LVEF), TIMI grade and residual stenosis of the infarct-related coronary artery. A follow up questionnaire was performed one year after hospital discharge to determine the relation to the occurrence of cardiac events (unstable angina, reinfarction, PTCA, bypass surgery and death).
Results:
30 patients developed 34 cardiac events. Four patients died. Two thirds of the 'cardiac events' in the year of follow-up were revascularization procedures mostly selected by evidence of ischemia on 99mTc perfusion scintigraphy and/or stress-echocardiography. These two methods were significantly associated with the development of new cardiac events (stress-echocardiography: p < 0.01; 99mTc perfusion scintigraphy: p < 0.006). Parameters of bicycle ergometry and variables of coronary angiography were not related to an increased risk of future cardiac events. The number of 'hard cardiac events'--death or nonfatal AMI--was too small (8%) in these patients who are able to exercise to make statistical comparisons.
Conclusions:
The study underlines the necessity of early noninvasive risk assessment to identify patients at a greater risk among survivors of uncomplicated AMI treated with thrombolytics who are clinically stable in the early postinfarction period. PTCA and coronary bypass surgery is performed in one third of these patients selected mostly by evidence of ischemia on 99mTc perfusion scintigraphy and/or stress-echocardiography. Results of bicycle ergometry are of limited value in these patients within the first year after acute myocardial infarction.