Diagnostic and prognostic potential of non-invasive assessment of cerebral blood flow autoregulation

Abstract

Purpose. To study the potential of non-invasive assessment of cerebral blood flow autoregulation (CA) using cross-spectral analysis of slow dopplerographic patterns. Materials and methods. The study involved 40 healthy volunteers and 228 patients with different neurosurgical pathology: cerebral aneurysm - 50 cases, arteriovenous malformation - 52, traumatic brain injury - 61, communicating hydrocephalus - 24, parasagittal meningioma - 20, stenosis and thrombosis of the carotid arteries - 21. Blood flow velocity (BFV) in middle cerebral arteries was monitored using Multi Dop X (DWL, Germany), systemic blood pressure (BP) - noninvasively with Finapres (Ohmeda 2100 USA) within 4 minutes. CA was assessed by calculating the phase shift (PSM) between spontaneous slow oscillations of BP and BFV within the range of systemic Mayer waves (80-120 mHz) and amplitude of intracranial B-waves of BFV (AB) within the range from 8 to 50 mHz). Results and discussion. CA demonstrated different patterns in neurosurgical patients and varied from normal autoregulation to its complete absence. This indicates the degree of compensation of cerebral hemodynamics in pathological conditions such as intracranial hypertension, vasospasm, traumatic edema, ischemia, abnormal arteriovenous shunting. On the basis of perioperative evaluation of PSM and AB, the predictors of efficacy and outcome have been identified in patients with cerebral aneurysms in an acute period of hemorrhage, severe brain injury, cerebral arteriovenous malformations and communicating hydrocephalus. Conclusions. Analysis of slow-wave dopplerographic patterns of BFV in intracranial cerebral arteries and BP is informative, adequate, safe non-invasive way to assess CA in normal and pathological conditions. Perioperative assessment of these patterns can be used to predict the effectiveness of treatment in patients with different neurosurgical pathology.