Diabetes mellitus and insulin resistance associate with left ventricular shape and torsion by cardiovascular magnetic resonance imaging in asymptomatic individuals from the multi-ethnic study of atherosclerosis

Background: Although diabetes mellitus (DM) and insulin resistance associate with adverse cardiac events, the associations of left ventricular (LV) remodeling and function with compromised glucose metabolism have not been fully evaluated in a general population. We used cardiovascular magnetic resonance (CMR) to evaluate how CMR indices are associated with DM or insulin resistance among participants before developing cardiac events. Methods: We studied 1476 participants who were free of clinical cardiovascular disease and who underwent tagged CMR in the Multi-Ethnic Study of Atherosclerosis (MESA). LV shape and longitudinal myocardial shortening and torsion were assessed by CMR. A higher sphericity index represents a more spherical LV shape. Multivariable linear regression was used to evaluate the associations of DM or homeostasis model assessment-estimated insulin resistance (HOMA-IR) with CMR indices. Results: In multiple linear regression, longitudinal shortening was lower in impaired fasting glucose than normal fasting glucose (NFG) (0.36% lower vs. NFG, p < 0.05); torsion was greater in treated DM (0.24 degrees/cm greater vs. NFG, p < 0.05) after full adjustments. Among participants without DM, greater log-HOMA-IR was correlated with greater LV mass (3.92 g/ index, p < 0.05) and LV mass-to-volume ratio (0.05 /index, p < 0.01), and lower sphericity index (-1.26/index, p < 0.01). Greater log-HOMA IR was associated with lower longitudinal shortening (- 0.26%/index, p < 0.05) and circumferential shortening (- 0.30%/index, p < 0.05). Torsion was positively correlated with log-HOMA-IR until 1.5 of log-HOMA-IR (0.16 degrees/cm/index, p = 0.030).), and tended to fall once above 1.5 of log-HOMA-IR (- 0.50 degrees/cm/index, p= 0.203). The sphericity index was associated negatively with LV mass-to-volume ratio (- 0.02/%, p < 0.001) and torsion (- 0.03 degrees/cm/%, p < 0.001). Conclusions: Glucose metabolism disorders are associated with LV concentric remodeling, less spherical shape, and reduced systolic myocardial shortening in the general population. Although torsion is higher in participants who are treated for DM and impaired insulin resistance, myocardial shortening was progressively decreased with higher HOMA-IR and torsion was increased only with less severe insulin resistance.