Myocardial interstitial fibrosis and subclinical left ventricular systolic dysfunction in type 2 diabetes mellitus patients with obesity: a 3.0 T MRI study

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) who are obese have increased risk of cardiovascular events. This study aimed to investigate the impact of obesity on myocardial interstitial fibrosis and its association with subclinical left ventricular (LV) systolic dysfunction in patients with T2DM. METHODS: Eighty-one T2DM patients without obesity, 48 patients with obesity and 40 matched lean healthy controls were prospectively recruited and underwent cardiac magnetic resonance imaging. Extracellular volume (ECV), 3-D feature tracking strain including LV radial (GRS), circumferential (GCS) and longitudinal (GLS) peak strains were evaluated from T1 mapping and cine images, and compared among the groups. RESULTS: Compared with controls, the LV GRS and GLS were significantly lower and ECV significantly higher in T2DM patients without obesity, and they were even lower or higher in patients with obesity than in both controls and patients without obesity. The LV GCS was significantly lower in patients with obesity than that in controls. Multivariable linear regression analyses demonstrated that obesity was independently associated with ECV (β = 2.147, p = 0.006), LV GRS and GLS (β = - 3.427 and 1.408, p = 0.019 and = 0.001, respectively) in patients with T2DM. When ECV was included in the regression analyses, both obesity and ECV were independently associated with LV GLS (β = 1.540 and 0.118, p < 0.001 and = 0.019, respectively). CONCLUSIONS: In patients with T2DM, there was more severe myocardial interstitial fibrosis and subclinical LV systolic dysfunction in patients with obesity, and increased myocardial fibrosis is independently associated with impaired LV systolic function. These results indicate the potential clinical significance of weight management in T2DM patients with obesity.