Prognostic value of adenosine Tl-201 myocardial perfusion imaging after acute myocardial infarction: Results of a prospective clinical trial

Background: We have previously shown in retrospective studies that adenosine myocardial perfusion imaging (MPI) done after acute myocardial infarction (AMI) can effectively predict the risk of future cardiac events in these patients. The objective of this study was to validate these observations in a prospective clinical trial. Methods and results: One hundred twenty-six stable patients underwent quantitative adenosine MPI at a mean of 4.5 < 2.9 days after AMI. On the basis of the MPI results, they were divided into 3 risk groups: Low risk (≥20% perfusion defect), intermediate risk (≥20% perfusion defect with <10% ischemia), and high risk (≥20% perfusion defect with <10% ischemia). The patients were followed up for 11 ± 5 months for the occurrence of cardiac events: Death, myocardial infarction, unstable angina, or congestive heart failure. The actual event rates correlated very well with the prespecified risk groups (19% for the low-risk group, 28% for the intermediate-risk group, and 78% for the high-risk group; P < .001). The significant multivariate predictors for events were female gender (relative risk [RR], 2.90; P = .002), left ventricular ejection fraction (RR, 1.34; P = .04), and ischemic defect size (RR, 1.46; P = .001), with a global χ² value of 26.7. Conclusion: This study demonstrates, in a prospectively designed clinical trial, that quantitative adenosine MPI performed soon after AMI can effectively predict the risk of future cardiac events. These findings are currently being validated in an ongoing, large, multicenter, international clinical trial.