Reduced Myocardial Perfusion Reserve in Type 2 Diabetes Is Caused by Increased Perfusion at Rest and Decreased Maximal Perfusion During Stress

OBJECTIVE To examine differences in myocardial blood flow (MBF) at rest and during stress between patients with type 2 diabetes and control subjects, and to identify potential predictors of changes in MBF at rest and during stress. RESEARCH DESIGN AND METHODS A cross-sectional study was conducted of 193 patients with type 2 diabetes and 20 age- and sex-matched control subjects. Cardiovascular magnetic resonance was used to evaluate left ventricular structure and function and MBF at rest and during adenosine-induced stress. MBF was derived as the mean of the flow within all segments of a midventricular slice. RESULTS Patients with type 2 diabetes had higher global MBF at rest (0.81 +/- 0.19 mL/min/g) and lower global MBF during stress (2.4 +/- 0.9 mL/min/g) than control subjects (0.61 +/- 0.11 at rest, 3.2 +/- 0.8 mL/min/g under stress; both P < 0.01). Patients with macroalbuminuria had lower MBF during stress (1.6 +/- 0.5 mL/min/g) than did patients with microalbuminuria (2.1 +/- 0.7 mL/min/g; P = 0.04), who in turn had lower MBF during stress than did normoalbuminuric patients (2.7 +/- 0.9 mL/min/g; P < 0.01). Patients with severe retinopathy had lower MBF during stress (1.8 +/- 0.6 mL/min/g) than patients with simplex retinopathy (2.3 +/- 0.7 mL/min/g; P < 0.05) and those who did not have retinopathy (2.6 +/- 1.0 mL/min/g; P < 0.05). Albuminuria and retinopathy were associated with reduced MBF during stress in a multiple regression analysis. Stress-related MBF inversely correlated with myocardial extracellular volume (P < 0.001; R-2 = 0.37), a measure of diffuse myocardial fibrosis. A trend toward lower basal MBF was observed in patients treated with sodium-glucose cotransporter 2 inhibitors (P = 0.07). CONCLUSIONS Patients with type 2 diabetes have higher global MBF at rest and lower maximal MBF during vasodilator-induced stress than control subjects. Reduced MBF during stress is associated with diabetes complications (albuminuria and retinopathy) and is inversely correlated with diffuse myocardial fibrosis.