Association Between Non‐Obstructive Coronary Atherosclerosis and Myocardial Work in Patients with Type 2 Diabetes Mellitus: A Coronary CT Angiography Study

AIMS: Despite advances in cardiovascular prevention, patients with type 2 diabetes mellitus (T2DM) remain at increased risk of developing subclinical myocardial dysfunction before overt cardiovascular disease becomes clinically apparent. Whether anatomically defined non-obstructive coronary atherosclerosis is associated with impaired myocardial work before obstructive coronary artery disease (CAD) develops remains unknown. This study investigated the association between coronary atherosclerotic burden on coronary computed tomography angiography (CCTA) and myocardial work in patients with T2DM and preserved left ventricular ejection fraction (LVEF). METHODS: In this retrospective cross-sectional study, consecutive T2DM patients who underwent both CCTA and transthoracic echocardiography a median of 41 days apart (interquartile range 31-57) were categorized by Coronary Artery Disease Reporting and Data System (CAD-RADS 2.0) categories 0-2. Global work efficiency (GWE) was the predefined primary outcome. Associations with myocardial work were evaluated using Jonckheere-Terpstra trend analyses and multivariable linear regression, with CAD-RADS modelled both as an ordinal term and categorically, and with adjustment extended beyond the original covariate set to include body mass index, diabetes duration, smoking, heart rate and estimated glomerular filtration rate. Secondary outcomes were corrected for multiplicity using the Holm procedure. RESULTS: Among 114 patients (CAD-RADS 0, n = 21; CAD-RADS 1, n = 46; CAD-RADS 2, n = 47), GWE declined progressively across increasing CAD-RADS categories (98.0 ± 0.4%, 96.2 ± 1.1% and 93.0 ± 3.5%), while global wasted work increased (37 [interquartile range 32-44], 67 [61-77] and 98 [90-103] mmHg%; both p for trend <0.001). Global longitudinal strain (GLS) did not differ significantly (-20.1 ± 2.1%, -19.7 ± 1.9% and -19.3 ± 3.1%; p for trend = 0.239), and left ventricular ejection fraction remained normal in every category although a modest downward trend was present (p for trend = 0.011). Each one-category increase in CAD-RADS was independently associated with a 2.69 percentage-point lower GWE (95% CI -3.36 to -2.03) and a 30.6 mmHg% higher global wasted work (95% CI 28.0 to 33.3; both p < 0.001), with consistent findings for the Agatston score. CONCLUSIONS: In patients with T2DM and preserved LVEF, non-obstructive coronary atherosclerosis was independently associated with impaired myocardial mechanical efficiency, whereas global longitudinal strain did not differ significantly across categories. Because the design was cross-sectional, these findings describe an association and cannot establish causality or temporal sequence; prospective studies are required to determine whether myocardial work adds incremental prognostic value.