Longitudinal 4D flow cardiac MR demonstrates that STEMI patients with reduced ejection fraction have persistently altered left ventricular kinetic energy profiles over 12 months, suggesting early and fixed impairment in diastolic function.
Background: Four-dimensional (4D) flow cardiac magnetic resonance (cardiac MR) imaging provides quantification of intracavity left ventricular (LV) flow kinetic energy (KE) parameters in three dimensions.ST-elevation myocardial infarction (STEMI) patients have been shown to have altered intracardiac blood flow compared to controls; however, how 4D flow parameters change over time has not been explored previously.Purpose: Measure longitudinal changes in intraventricular flow post-STEMI and ascertain its predictive relevance of longterm cardiac remodeling.Study Type: Prospective.Population: Thirty-five STEMI patients (M:F = 26:9, aged 56 AE 9 years).Field Strength/Sequence: A 3 T/3D EPI-based, fast field echo (FFE) free-breathing 4D-flow sequence with retrospective cardiac gating.Assessment: Serial imaging at 3-7 days (V1), 3-months (V2), and 12-months (V3) post-STEMI, including the following protocol: functional imaging for measuring volumes and 4D-flow for calculating parameters including systolic and peakE-wave LVKE, normalized to end-diastolic volume (iEDV) and stroke volume (iSV).Data were analyzed by H.B. (3 years experience).Patients were categorized into two groups: preserved ejection fraction (pEF, if EF > 50%) and reduced EF (rEF, if EF < 50%).Statistical Tests: Independent sample t-tests were used to detect the statistical significance between any two cohorts.P < 0.05 was considered statistically significant.Results: Across the cohort, systolic KEi sv was highest at V1 (28.0 AE 4.4 μJ/mL).Patients with rEF retained significantly higher systolic KEi sv than patients with pEF at V2 (18.2 AE 3.4 μJ/mL vs. 6.9AE 0.6 μJ/mL, P < 0.001) and V3 (21.6 AE 5.1 μJ/ mL vs. 7.4 AE 0.9 μJ/mL, P < 0.001).Patients with pEF had significantly higher peakE-wave KEi EDV than rEF patients throughout the study (V1: 25.4 AE 11.6 μJ/mL vs. 18.1 AE 9.9 μJ/mL, P < 0.03, V2: 24.0 AE 10.2 μJ/mL vs. 17.2AE 12.2 μJ/mL, P < 0.05, V3: 27.7 AE 14.8 μJ/mL vs. 15.8AE 7.6 μJ/mL, P < 0.04).Data Conclusion: Systolic KE increased acutely following MI; in patients with pEF, this decreased over 12 months, while patients with rEF, this remained raised.Compared to patients with pEF, persistently lower peakE-wave KE in rEF patients is suggestive of early and fixed impairment in diastolic function.Evidence Level: 1 Technical Efficacy: Stage 3
Ben‐Arzi et al. (Fri,) studied this question.
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