The adverse effects of metabolic disorder on left ventricular myocardial mechano-energetic efficiency and dysfunction in ischemic cardiomyopathy: insight from a cardiac MRI study

PURPOSE: Metabolic risk factors (MetF) have emerged as the leading drivers of ischemic cardiomyopathy (ICM) worldwide. However, in patients who have already experienced myocardial ischemia/infarction, whether and in what pattern the MetF act on the heart needs to be further elucidated. This study aims to determine the adverse effects of MetF on left ventricular (LV) indexed myocardial mechano-energetic efficiency (MEEi) and dysfunction in patients with ICM, and further clarify which MetF classification is more clinically significant. MATERIALS AND METHODS: This study retrospectively included 201 patients with ICM who underwent cardiac magnetic resonance imaging (MRI) examinations, and further divided them into the following three groups according to the number of coexisting MetF: The groups with no MetF (MetF-0 group, n = 32), with 1-2 MetF (MetF-1, n = 92) and with 3-5 MetF (MetF-2, n = 77). The clinical variables and MRI-derived parameters were measured and compared among the three groups. Multivariate linear regression analysis was performed to determine independent correlation of MetF on LV MEEi and strain in ICM patients. RESULTS: LV global circumferential peak strain (PS) gradually decreased from MetF-0 group, through MetF-1 group, to MetF-2 group (- 9.52 ± 2.70% vs. - 7.62 ± 2.73% vs. - 6.50 ± 2.70%, P < 0.001). MetF-1 and MetF-2 groups both showed lower MEEi, lower LV global radial and longitudinal PS than MetF-0 group (Both P < 0.001), while there was no statistically significant difference between MetF-1 and MetF-2 groups (P > 0.05). Multivariate analyses indicated that the coexisting any MetF was independently associated with decreased LV MEEi (β = - 0.093, P = 0.018) and PS (Radial, β = - 0.232, P < 0.001; Circumferential, β = 0.156, P = 0.002; Longitudinal, β = 0.192, P = 0.008), and the increase in the number of coexisting MetF was only related to the reduction of circumferential PS (β = 0.238, P = 0.006). CONCLUSIONS: Our results revealed whether coexisting any MetF, rather than coexisting a greater number of MetF, is associated with the reduction of LV myocardial mechano-energetic efficiency and dysfunction in patients with ICM, suggesting that clinicians should promptly identify and treat any coexisting MetF in the management of ICM patients.