Changing cerebral blood flow velocity by transcranial Doppler during head up tilt in patients with diabetes mellitus

Objective Diabetes mellitus is an independent risk factor for poor prognosis in patients with ischemic stroke. It is known that diabetes mellitus directly affects cerebral vasculature as a secondary, long-term complication of cerebral circulation, and causes cerebral blood flow abnormalities. The abnormalities of cerebral autoregulation also poorly affects the prognosis of ischemic stroke. In this study, we aimed to show the cerebral autoregulation with transcranial Doppler (TCD) ultrasound in diabetic patients with autonomic nervous system abnormalities, determined with electrophysiological studies. Material and method Twenty healthy controls and 39 patients, who had at least 2 years of diabetes mellitus, were evaluated (age ranges: 42–75 years). The patients were divided into two groups according to sympathetic skin response and R–R interval variation studies: (1) patients with autonomic neuropathy; (2) patients without autonomic neuropathy. Blood flow velocities were measured during supine position and after the patients were raised upright position on head up tilt table. Arterial blood pressures and heart rates were also evaluated. Results Mean blood flow velocities of diabetic patients with autonomic neuropathy were found more decreased at 90 s after the patients were raised upright position. Discussion Autonomic neuropathy due to diabetes mellitus affects cerebral autoregulation, and by this way cerebral perfusion loses protection against hemodynamical changes.