LAUSR

Objectives: To evaluate 1) myocardial flow reserve (MFR) and coronary artery calcium (CAC) in patients with type 1 diabetes (T1D) with or without albuminuria and in non-diabetic controls; 2) MFR and CAC in patients with T1D and retinopathy. MFR reflects the function of large epicardial arteries and myocardial microcirculation. CAC represents structural aspects of atherosclerosis. Methods: Cross-sectional study in T1D, stratified by normo- (n = 30) and macroalbuminuria (n = 30), and 30 controls. MFR and CAC was evaluated by cardiac 82Rb PET/CT. Results: MFR was similar in normoalbuminurics and controls (3.1 ± 0.8 vs 3.0 ± 0.79; p = 0.74). Macroalbuminurics had lower MFR compared to normoalbuminurics (2.1 ± 0.9 vs 3.1 ± 0.8; p < 0.0001). CAC score (median[IQR]) was higher in normoalbuminurics compared to controls (72[22–247] vs 0[0–81], p = 0.018), and comparable between macro- and normoalbuminurics. MFR was comparable in T1D with simplex retinopathy (n = 24) compared to no retinopathy (n = 12; p = 0.11), but lower in proliferative (n = 23) compared to simplex retinopathy (p = 0.02). CAC score was comparable between groups of retinopathy. Lower MFR was associated with higher CAC, UACR, age, 24-h SBP and lower eGFR. In multivariate regression lower MFR was associated with higher UACR and age, lower eGFR and smoking (R2 = 0.39). Higher CAC was associated with lower MFR, higher age and 24-h SBP (R2 = 0.34). Conclusion: Myocardial microvascular function was comparable in controls and patients with T1D and normoalbuminuria; but impaired in the presence of macroalbuminuria and/or proliferative retinopathy. Coronary calcification was also high, but not explained by albuminuria. This signifies that functional aspects of atherosclerosis correlate to albuminuria and retinopathy to larger extent than the structural.