Hemorheology and vascular reactivity in patients with diabetes mellitus type 2

The study aimed to investigate the hemorheological parameters in patients with diabetes mellitus type 2 and to estimate their relationship with the cerebral and cutaneous blood flow and their responses to postural changes. The basic hemorheological constituents: hematocrit (Ht), fibrinogen (Fib), whole blood (WBV) and plasma viscosity (PV) were examined in 20 patients with diabetes mellitus type 2 and in 10 healthy age and sex matched controls. Blood flow velocity in the middle cerebral artery (MCA) was measured by transcranial Doppler monitoring at rest and during 5-min head-up tilt. Also laser Doppler-recorded tiptoe skin blood flow was investigated and venoarteriolar reflex perfusion responses to postural impact was monitored. Significant increase of Fib and WBV at shear rates of 0.0237 s(-1) to 128.5 s(-1) in the patients in comparison to controls was found. The postural challenge caused decrease of the cerebral blood flow velocity and increase of the resistance index (RI) in the diabetic patients. The initial mean skin perfusion values of the tiptoes and the venoarteriolar constriction response indices were significantly higher in the diabetes group. In the patients with diabetes mellitus type 2 the increased blood viscosity values were associated with impaired cerebrovascular and peripheral vascular responces.