Effect of changes in perfusion defect size during serial stress myocardial perfusion imaging on cardiovascular outcomes in patients treated with primary percutaneous coronary intervention after myocardial infarction

Background. We evaluated the prognostic value of changes in perfusion defect size (PDS) on serial MPS in patients treated with primary percutaneous coronary intervention (PCI) after acute myocardial infarction (AMI). Methods. We enrolled 112 patients treated with primary PCI after AMI who underwent two stress MPS within 1 month and after 6 months. Improvement in PDS was defined as a reduction ‡5%. Remodeling was defined as an increase in left ventricular (LV) end-diastolic volume index ‡20%. Cardiac events included cardiac death, nonfatal MI, unstable angina, repeated revascularization, and heart failure. Results. During a median follow-up of 86 months, 22 events occurred. Event rate was higher (P < .01) in patients with worsening of PDS compared to those with unchanged or improved PDS. Moreover, patients with remodeling had a higher (P < .001) event rate compared to those without. At Cox analysis, worsening of PDS and remodeling resulted independent predictors of events (both P < .01). Patients with both worsening of PDS and remodeling had the worst event-free survival (P <.001). Conclusion. In patients treated with primary PCI after AMI, worsening of PDS and remodeling are associated to higher risk of events at long-term follow-up. Gated stress MPS improves risk stratification in these patients.