[The prognostic value of myocardial infarct size measured by cardiovascular magnetic resonance in patients with acute ST-segment elevation myocardial infarction].

Objective: To investigate the prognostic value of infarct size (IS) in patients with acute ST-segment elevation myocardial infarction (STEMI) underwent primary percutaneous coronary intervention (PCI). Methods: A total of 104 patients with acute STEMI who underwent primary PCI treatment in Shengjing Hospital of China Medical University from February 2017 to November 2018 were included in the present study. All patients underwent cardiovascular magnetic resonance (CMR) within one week after primary PCI treatment. The subjects were followed up for two years. Major adverse cardiac events (MACE) included new onset congestive heart failure and/or recurrent nonfatal myocardial infarction and/orcardiac death. The optimal IS cutoff value for MACE was determined by receiver operating character (ROC) curve. Based on the IS cutoff value, the patients were divided into the high IS group and the low IS group. Clinical characteristics between the two groups were compared. A cox regression model was used to analyze the prognostic value of IS in acute STEMI patients treated with primary PCI for the adverse events. Results: The IS cutoff value determined by ROC curve was 13.55%. 50 patients were in the high IS group (IS≥13.55%) and 54 patients were in the low IS group (IS<13.55%). More female patients [14 cases (28.0%) vs. 6 cases (11.1%)] were in the IS group, and a higher proportion of patients in the high IS group had anterior myocardial infarction [27 cases (54.0%) vs. 16 cases (29.6%)] or microvascular obstruction [32 cases (64.0%) vs. 16 cases (29.6%)]. White blood cell counts [11.25(8.90, 13.38) ×109/L vs. 9.25(7.58, 11.00) ×109/L], troponin I levels [50.63(16.56, 76.30)μg/L vs. 16.58(2.66, 38.42)μg/L] and brain natriuretic peptide levels [178.10(79.70, 281.95)μg/L vs. 79.60(42.83, 183.90)μg/L] in the high IS group were higher than those in the low IS group (P<0.05), and left ventricular ejection fraction [(45.15±10.65)% vs. (51.95±12.91)%] in the high IS group was lower than that in the low IS group (P<0.05). Multivariate Cox regression analyses showed that IS was independently associated with the risk of cardiac death in patients with acute STEMI two years after primary PCI(P=0.033, HR=1.075, 95%CI1.006-1.148). Every 1% increase in IS was associated with a 7.5% increase in cardiac death. Conclusions: Infarct size, measured by CMR within one week after primary PCI, is strongly associated with cardiac death in patients with acute STEMI two years after primary PCI. IS could be used as an index for the prognosis of patients with acute STEMI.