Sensibility and specificity of laser speckle contrast imaging according to Endo-PAT index in type 1 diabetes.

Objectives: To find out an normality value for microvascular response (physiological and pharmacological) assessed through laser speckle contrast imaging (LSCI) based on Endo-PAT, which identifies the ones with Endothelial Dysfunction (ED) in patients with Type 1 Diabetes (T1D).

Methods: Patients with T1D, aged ≥12years underwent a clinical-epidemiological questionnaire. Fasting blood samples were obtained (lipid profile, glycemic control and levels of C-reactive protein). Vascular reactivity was assessed in the forearm through the technique of LSCI at baseline, during post occlusive reactive hyperemia (PORH) and during iontophoresis of acetylcholine (ACh) and peripheral arterial tonometry was performed by supplying the RHI through Endo-PAT device.

Results: 189 patients were evaluated, 97 women (51.3%) with T1D, aged 32±13years and with a disease duration of 16 (6-21) years and mean A1c of 9.2% (±2.2). Receiver Operating Characteristics curve (ROC) analysis according to RHI showed that the Area under curve (AUC) of ACh of 10,369 Laser Speckle Perfusion Unit (LSPU) presented sensitivity and specificity of 65% and 87,5%, respectively, (p=0.002) in those patients with T1D's duration <5years. Overall, no test of vascular reactivity was able to distinguish the ideal cuttoff based on RHI.

Conclusion: In the present study, we could find an ideal cut off value of microcirculation assessment through endothelium-dependent vasodilation to ACh using LSCI according to Endo-PAT's score, only in those under 5years of disease duration. Further prospective studies shall be conducted to evaluate its predictive cardiovascular value.