Non-invasive assessment of microcirculation by sidestream dark field imaging as a marker of coronary artery disease in diabetes

PURPOSE: In diabetes, generalised microvascular disease and coronary artery disease (CAD) are likely to occur in parallel. We used a sidestream dark field (SDF) handheld imaging device to determine the relation between the labial microcirculation parameters and CAD in asymptomatic patients with diabetes. METHODS: SDF imaging was validated for assessment of labial capillary density and tortuosity. Thereafter, mean labial capillary density and tortuosity were evaluated and compared in non-diabetic controls, and in asymptomatic patients with type 1 and type 2 diabetes. In diabetic patients, mean capillary density and tortuosity were compared according to the presence of CAD. RESULTS: Both type 1 and type 2 diabetes were associated with increased capillary density and tortuosity. In diabetes, mean capillary density was an independent predictor of elevated coronary artery calcium (CAC) (p = 0.03) and obstructive CAD on computed tomography angiography (p = 0.01). Using a cut-off mean capillary density of 24.9 (per 0.63 mm(2)) the negative predictive value was 84% and 89% for elevated CAC and obstructive CAD. Likewise, capillary tortuosity was an independent predictor of increased CAC (p = 0.01) and obstructive CAD (p = 0.04). CONCLUSION: Assessment of labial microcirculation parameters using SDF imaging is feasible and conveys the potential to estimate vascular morbidity in patients with diabetes, at bedside.