Retinal microvascular features associated with subclinical cardiovascular dysfunction in type 2 diabetes

Aims Microvascular dysfunction is implicated in the pathogenesis of many cardiovascular (CV) diseases, with retinal imaging providing a non-invasive window into microvascular health. Prior evidence links retinal microvascular features (RVF) with cardiac structure and function, yet these relationships remain incompletely characterised. This study systematically examined associations between RVFs and measures of subclinical CV dysfunction derived from CMR imaging. Methods and results 182 participants with type 2 diabetes were considered for inclusion in this cross-sectional study. Fifteen CMR measures of cardiac structure, function, tissue characterisation, adiposity, and aortic distensibility were derived. 128 participants (70%) had eligible retinal images. An artificial intelligence (AI)-enabled retinal image analysis tool (QUARTZ) quantified eight RVFs: arteriolar and venular diameter, area, calibre uniformity, and tortuosity. Multivariable regression examined RVF-CMR associations, expressed as change in CMR measures per 1-standard deviation (SD) increase in RVF. Five RVF-CMR associations remained significant after adjustment for confounders. Venular tortuosity was associated with a 0.5ms greater left ventricular (LV) T2 mean, 0.6% worsening in LV global longitudinal strain, and a 2 mL greater left atrial max volume. Arteriolar calibre uniformity and venular area were each associated with 9ms lower LV T1 mean and 0.2x10-3mmHg-1 greater proximal descending aortic distensibility, respectively. Conclusion In a diabetic cohort, we identified novel and biologically coherent associations between RVF and CMR measures. Notably, venular tortuosity was associated with a constellation of CMR changes consistent with subclinical myocardial dysfunction. These findings support the potential role of retinal imaging in evaluating CV dysfunction prior to overt disease.