Dynamic cerebral autoregulation in stroke patients with a central sympathetic deficit

Objective - To investigate the functional role of the sympathetic innervation on cerebral autoregulation. Materials and methods - Seventeen patients with infarction of the dorsolateral medulla oblongata affecting central sympathetic pathways (Wallenberg's syndrome) and 21 healthy controls were included in the study. Cerebral blood flow velocity (CBFV) in the medial cerebral artery was investigated using transcranial Doppler ultrasound during decrease in cerebral perfusion pressure induced by leg-cuff test and tilt table. Results - Upon leg-cuff test, changes of cerebral blood flow and mean arterial blood pressure as well as autoregulatory index did not differ between patients or controls. No differences were found in changes of CBFV, mean arterial blood pressure and heart rate between patients or controls during the tilt table test. Conclusions - We suggest that the sympathetic nervous system does not have an influence on cerebral autoregulation after decrease in perfusion pressure under normotonous conditions.