International variations in the ischemic burden post-acute myocardial infarction: prognostic implications

To determine if there is a variation in the ischemic burden post-acute myocardial infarction (AMI), as assessed by myocardial perfusion imaging (MPI), between different populations in different geographic locations and to see if this variation is associated with different clinical outcomes.

We characterized the MPI findings in 104 stable patients who were hospitalized with AMI at the American University of Beirut Medical Center (AUBMC), a tertiary referral hospital in an East Mediterranean country and we compared them to 126 patients who were enrolled according to a similar protocol in a previous study done at Baylor College of Medicine (BCM), Houston, Texas. There were no differences between the two populations with respect to prevalence of diabetes, hypertension, smoking, the use of thrombolysis, percentage of anterior MIs, Q-wave MIs, and multivessel disease on coronary angiography. However, the quantified ischemic defect size in the BCM population was double that in the AUBMC population (12 +/- 12% vs 6 +/- 8%, P < .01). This was associated with almost doubling of the 1 year event rate of death/myocardial infarction (18.3% vs 10.6%, P = .02) in the BCM population.

Our study suggests that the ischemic burden post-AMI, as assessed by MPI, might vary between different populations in different geographic locations. This variation carries important prognostic implications and is associated with different patient outcomes.