Impella Effects on Reverse Myocardial Remodeling in Anterior ST-Elevation Myocardial Infarction: Insights from a Comprehensive Analysis of Acute and Chronic MRI Findings

Abstract Background Late adverse myocardial remodeling after ST elevation myocardial infarction (STEMI) is strongly associated with cardiac death. Global Longitudinal strain (GLS) and circumferential diastolic strain rate (CDSR) derived cardiovascular magnetic resonance imaging (CMRI) is a powerful predictor of late myocardial remodeling. However, Impella’s effects on CMRI-based myocardial remodeling after STEMI is not fully understood. Methods We retrospectively compared the CMRI-derived strain and left ventricular ejection fraction (LVEF) in the acute (18 [14–22]) vs 14 [6–22] days, P = 0.43) and chronic phases (118 [102–242] vs 117 [101–202] days, P = 1.0) after broad anterior STEMI. Results Five patients received an Impella before percutaneous coronary intervention (PCI), and 7 were given intra-aortic balloon pumping (IABP). There were no significant differences in age (67 ± 10 vs. 63 ± 13, P = 0.53), peak creatine kinase levels (2595 [2069–12932] vs. 4372 [2941–5601] IU/L, P = 0.76), and LVEF at admission (51 ± 11 vs. 50 ± 9%, P = 1.0) between the two groups. The Impella group showed significantly better acute CMRI-derived LVEF (49 ± 10 vs. 36 ± 8%, P = 0.03) and CDSR (0.9 ± 0.2 vs. 0.5 ± 0.3 s⁻¹, P = 0.018) despite no significant difference in acute GLS between the two groups (-9.4 ± 2.2 vs. -8.7 ± 1.6%, P = 0.88). In the chronic phase, CMRI-derived LVEF and GLS were significantly higher in the Impella group (54 ± 9 vs. 39 ± 5%, P = 0.018; -9.9 ± 1.3 vs. -6.5 ± 2.2%, P = 0.01). Conclusions The Impella implantation leads to better LVEF and CDSR in the acute phase compared to IABP, and further to maintenance of both LVEF and GLS through the chronic phase. Unlike with IABP, LV unloading brought about by Impella, significantly contributed to the reverse remodeling process.