Retinal microvascular dysfunction in patients with coronary artery disease with and without heart failure: a continuum?

Aims Dynamic retinal vessel analysis is a novel, non-invasive method to assess microvascular function. The primary aim of this study was to investigate whether retinal microcirculation is impaired in patients with stable coronary artery disease (CAD) compared to patients with heart failure due to CAD (ischaemic heart failure, IHF). Methods and results A total of 150 adults were enrolled to prospectively assess micro- and macrovasculature. The pre-defined primary outcome was flicker-induced arterial dilatation (FIDa) in patients with CAD [n = 40; median age 63 years, interquartile range (IQR) 53-70] and IHF (n = 40; median age 63 years, IQR 59-71) compared to healthy controls (HC, n = 70; median age 57 years, IQR 41-69). Secondary outcomes included arterial stiffness, flow-mediated dilatation, biomarkers, and ergospirometry parameters. Patients with CAD demonstrated impairment in FIDa that was even more pronounced in patients with IHF (CAD: 1.93 +/- 0.28% vs. IHF: 0.41 +/- 0.28%, P < 0.001; FIDa in HC: 3.69 +/- 0.21%, both P < 0.001) adjusting for age, sex, concomitant medication, and co-morbidities. While pulse wave velocity was increased and flow-mediated dilatation reduced in CAD and IHF patients (both P < 0.001 compared to HC), neither differed between CAD and IHF patients. N-terminal pro-B-type natriuretic peptide (r = -0.49, P < 0.001,) and high-sensitivity troponin T (r = -0.28, P = 0.003) correlated with FIDa. Intriguingly, mean metabolic equivalents (5.3 +/- 2.3 kcal/kg/h, n = 39) showed a positive correlation with FIDa (r = 0.58, P < 0.001). Conclusion This study demonstrates a decline of retinal arterial function in CAD patients that is significantly more pronounced in the presence of reduced left ventricular ejection fraction, suggesting a continuum of microvascular damage.