Myocardial Tissue Characterization by Contrast-Enhanced Cardiac Magnetic Resonance Imaging in Patients With Combined Diabetes Mellitus and Obstructive Sleep Apnea

Introduction: Overlap of type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) increases the risk of heart failure possibly mediated by myocardial fibrosis. Hypothesis: T2DM+OSA overlap increases myocardial fibrosis. Methods: This was a prospective study where 141 participants (Control: 28; T2DM only: 27; OSA only: 29; T2DM+OSA: 57) underwent a sleep study and cardiac magnetic resonance. The measures of interest were LV and RV extracellular volume (ECV), native T1 and cardiomyocyte size (tau). Differences were tested with Kruskal-Wallis. The groups 'T2DM only' and 'OSA only' were combined (Control; T2DM or OSA; T2DM+OSA) for trend analysis with Jonckheere-Terpstra test. Results: Groups had similar sex [Control (males): 54%; T2DM: 44%; OSA only: 52%; T2DM+OSA: 65%; p=0.31)]; OSA and OSA+T2DM participants were older (46± 15; 51±7.8; 53±10; 56±9.1* # years; respectively p=0.001; *p<0.05 vs. control, # p<0.05 vs. T2DM only) and had higher BMI (29.8±6.3; 31±4.8; 34±6.3*; 35.2±6.6* # kg/m 2 , respectively p=0.001). LV ECV increased progressively with highest values among subjects with T2DM and OSA (0.25±0.02%; 0.27±0.03%; 0.28±0.04%; 0.31±0.05%; respectively, p=0.001; p for trend<0.001). LV native T1 was similar across groups (995±91 ms; 986±112 ms; OSA: 977±132 ms; 1041±128 ms; respectively, p=0.39; p for trend=0.14), and the T2DM+OSA group had a marginally higher LV tau (0.15±0.04 s; 0.13±0.05 s; 0.12±0.04 s; 0.17±0.06 s; respectively, p= 0.05; p for trend=0.59). RV ECV (0.40±0.06%; 0.41±0.05%; 0.40±0.04%; 0.42±0.05%; respectively, p=0.70; p for trend=0.27) and RV native T1 (1105±164 ms; 1083±124 ms; 1063±189 ms; 1092±148 ms; p=0.85; p for trend=0.85) were similar. RV tau was similar but with a positive trend towards T2DM+OSA (0.087±0.029 s; 0.094±0.023 s; 0.990±0.033 s; 0.115±0.045 s; p= 0.17, p= 0.03). Conclusions: The overlap of T2DM and OSA has an incremental adverse effect on the LV ECV and may explain the increased risk of adverse cardiac events.