Increased Shear Rate Resistance and Fastest Kinetics of Erythrocyte Aggregation in Diabetes Measured With Ultrasound

OBJECTIVE—To measure with ultrasound the increased erythrocyte aggregation (EA) kinetics and adhesion energy between erythrocytes in patients with type 2 diabetes and poor metabolic control. RESEARCH DESIGN AND METHODS—Blood samples were analyzed in a Couette rheometer at 32 MHz following shear rate reductions from 500 s(−1) to residual shears of 0 (stasis), 1, 2, 10, 50, 100, and 200 s(−1). The increase in EA was determined with the integrated backscatter coefficient as a function of time and shear rate. RESULTS—The time required to form aggregates was shorter in diabetic patients at shear rates below 200 s(−1) (P < 0.01). Erythrocytes formed larger aggregates in diabetic patients than in control subjects (P < 0.05 at 2 to 100 s(−1)). CONCLUSIONS—Ultrasound can potentially noninvasively demonstrate, in vivo and in situ, the impact of local abnormal EA on arteriovenous flow disorders in diabetes.