A simple deep breathing test reveals altered cerebral autoregulation in type 2 diabetic patients

Abstract

Aims/hypothesis Patients with diabetes mellitus have an increased risk of stroke and other cerebrovascular complications. The purpose of this study was to evaluate the autoregulation of cerebral blood flow in diabetic patients using a simple method that could easily be applied to the clinical routine screening of diabetic patients. Methods We studied ten patients with type 2 diabetes mellitus and 11 healthy volunteer control participants. Continuous and non-invasive measurements of blood pressure and cerebral blood flow velocity were performed during deep breathing at 0.1 Hz (six breaths per minute). Cerebral autoregulation was assessed from the phase shift angle between breathing-induced 0.1 Hz oscillations in mean blood pressure and cerebral blood flow velocity. ResultsThe controls and patients all showed positive phase shift angles between breathing-induced 0.1 Hz blood pressure and cerebral blood flow velocity oscillations. However, the phase shift angle was significantly reduced (p<0.05) in the patients (48±9°) compared with the controls (80±12°). The gain between 0.1 Hz oscillations in blood pressure and cerebral blood flow velocity did not differ significantly between the patients and controls. Conclusions/interpretation The reduced phase shift angle between oscillations in mean blood pressure and cerebral blood flow velocity during deep breathing suggests altered cerebral autoregulation in patients with diabetes and might contribute to an increased risk of cerebrovascular disorders.

Dynamic Cerebral Autoregulation in Homozygous Sickle Cell Disease

“…This notion is supported by the finding that cerebral autoregulation is equally impaired in patients with Type 2 diabetes. 24,25 The higher variability in CBFV in the SCD group indicated a reduced capacity to buffer the transfer of BP surges to the cerebral tissue. Impairment of dynamic cerebrovascular control was confirmed by a reduced phase lead of the BP-to-CBFV transfer function in SCD.…”

Autonomic Blockade During Sinusoidal Baroreflex Activation Proves Sympathetic Modulation of Cerebral Blood Flow Velocity

“…If changes in CBFV or 0.1 Hz CBFV oscillations were only passively driven by BP changes, one should expect changes in the phase angle between the 0.1 Hz oscillations of BP and CBFV. 12,17,24,26,40 Instead, the phase angle between 0.1 Hz BP and CBFV oscillations showed stable and negative radiants. The negative radiants typically result from the high-pass filter function of CA 11,17,26 that attenuates CBFV fluctuations in response to BP fluctuations.…”

“…12,26 Only active mechanisms of CA buffer the transmission of BP fluctuations onto CBFV, and result in the negative phase shift between the oscillations of the CA-input signal BP and the CA-output signal CBFV. 12,17,24,26,40 If CBFV oscillations were not actively modulated, but resulted passively from BP oscillations, phase angles between 0.1 Hz oscillations of CBFV and BP would change with changes in BP, for example, during 0.1 Hz NS-induced sympathetic activation or upon carvedilol-induced sympathetic blockade. 5,11,12,26 Such passive phase angle changes have been reported in patients with impaired CA.…”

A look inside the diabetic brain: Contributors to diabetes-induced brain aging

“…Manifestations of diabetes-induced CNS complications may include structural alterations or brain atrophy, as well as changes in electrophysiological properties that ultimately result in deficits in cognitive performance [2]. These diabetes-induced CNS complications may be associated with or exacerbated by cardiovascular disease, including hypertension [3,4] and cerebral vascular complications [5–8]. Additional factors that may contribute to diabetes-induced cognitive impairment include disrupted insulin signaling and glucose homeostasis in the CNS [9].…”