Aims: The aim of this study was to determine the long-term prognostic value of infarct size and myocardial ischaemia on single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).
Methods and results: In total, 1092 STEMI patients who underwent primary PCI and SPECT MPI within 1-6 months were included (median follow-up time of 6.9 years). In the entire cohort, SPECT infarct size was independently associated with the composite of cardiac death or reinfarction [hazard ratio (HR) per 10% increase in summed rest score 1.33; 95% confidence interval (95% CI) 1.12-1.58; P = 0.001], whereas myocardial ischaemia was not (HR per 5% increase in summed difference score 1.18; 95% CI 0.94-1.48; P = 0.16). Addition of SPECT infarct size to a model including the clinical variables provided significant incremental prognostic value for the prediction of cardiac death or reinfarction (global χ2 13.8 vs. 24.2; P = 0.002), whereas addition of SPECT ischaemia did not add significantly (global χ2 24.2 vs. 25.6; P = 0.24). In the subgroup of patients with left ventricular ejection fraction (LVEF) ≤ 45%, SPECT infarct size was independently associated with cardiac death or reinfarction (HR 1.59; 95% CI 1.15-2.22; P = 0.006), whereas in patients with LVEF > 45%, only SPECT ischaemia was independently associated with cardiac death or reinfarction (HR 1.28; 95% CI 1.00-1.63; P = 0.050).
Conclusion: In patients with first STEMI and primary PCI, SPECT infarct size was independently associated with cardiac death and/or reinfarction, whereas myocardial ischaemia was not. In patients with LVEF ≤ 45%, SPECT infarct size was independently associated with cardiac death or reinfarction, whereas myocardial ischaemia was not. Conversely, in patients with LVEF > 45%, only SPECT ischaemia was independently associated with cardiac death or reinfarction.