Impaired diastolic filling and adverse event risks in patients with ST-segment-elevation myocardial infarction: insights from four-dimensional flow magnetic resonance imaging.

Background: Intra-cavity flow disorders have association with adverse cardiovascular events in patients with ST-segment elevation myocardial infarction (STEMI). This study aims to explore the characteristics of four-dimensional flow (4D-Flow) and its relationship with the adverse event risk scores in patients with STEMI. Methods: Forty patients with STEMI (38 males, mean age 54.35 years) and 20 healthy controls (18 males, mean age 50.40 years) were prospectively enrolled for cardiac magnetic resonance (CMR) imaging. The 4D-Flow data analysis was performed using the MASS post-processing software. Left ventricular (LV) flow kinetic energy (KE) parameters included LV KE, in-plane KE, systolic KE, diastolic KE, E-wave KE, A-wave KE, E wave/A wave ratio (E/A ratio), and time difference (TD). Adverse event risks were calculated in accordance with the criteria [Global Registry of Acute Coronary Events (GRACE) risk model version 2.0]. The correlation of CMR parameters with GRACE risk score was analyzed using Pearson or Spearman's correlation test. Significant variables (P<0.05) derived from the univariate forward regression method were integrated into the multivariable analysis, P<0.05. Results: The diastolic function KE parameters, TD, E/A and E-wave KEEDV, exhibited significant differences between the STEMI-high risk and STEMI-low risk groups [58.60 (36.20-68.50) vs. 32.50 (0-35.70) milliseconds, P=0.003; 0.64±0.34 vs. 0.89±0.44, P=0.036; 6.71 (5.30-8.10) vs. 7.74 (6.50-10.28) µJ/mL, P=0.038]. Both the E/A ratio and TD had independent correlations with the GRACE risk score (β*=-0.38, P=0.003; β*=0.57, P<0.001). Conclusions: 4D-Flow imaging revealed impaired diastolic filling in acute STEMI patients, which was associated with higher adverse event risk scores.