Predictive Value of Dynamic Cerebral Autoregulation Assessment in Surgical Management of Patients with High-Grade Carotid Artery Stenosis

Abstract

Dynamic cerebral autoregulation (DCA) capacity along with the degree of internal carotid artery (ICA) stenosis and characteristics of the plaque can also play an important role in selection of appropriate treatment strategy. This study aims to classify the patients with severe ICA stenosis according to preoperative state of DCA and to assess its dynamics after surgery. Thirty-five patients with severe ICA stenosis having different clinical type of disease underwent reconstructive surgery. DCA was assessed with transfer function analysis (TFA) by calculating phase shift (PS) between Mayer waves of blood flow velocity (BFV) and blood pressure (BP) before and after operation. In 18 cases, regardless of clinical type, preoperative PS on ipsilateral side was within the normal range and did not change considerably after surgery. In other 17 cases preoperative PS was reliably lower both in patients with symptomatic and asymptomatic stenosis. Surgical reconstruction led to restoration of impaired DCA evidenced by significant increase of PS in postoperative period. Our data suggest that regardless clinical type of disease various state of DCA may be present in patients with severe ICA stenosis. This finding can contribute to establishing the optimal treatment strategy, and first of all for asymptomatic patients. Patients with compromised DCA should be considered as ones with higher risk of stroke and first candidates for reconstructive surgery.

Dynamic cerebral autoregulation is an independent outcome predictor of acute ischemic stroke after endovascular therapy

“…The underlying pathophysiological mechanisms might be that the severe stenosis may significantly reduce cerebral perfusion pressure, which could reach its lower limit for autoregulation. Under these conditions, even slight reductions of BP may result in inadequate cerebral perfusion and would not be able to protect the brain from hemodynamic ischemic events [26]. With the development of TCD monitoring, dCA can be evaluated by simultaneous assessment of spontaneous fluctuations in BP and BFV in MCA (assessed by TCD) using different testing modalities in the time and frequency domain [20,27].…”

Predictive Value of Cerebrovascular Reserve in Patients with Carotid Artery Stenosis for Choosing Treatment Strategy

“…This method is On the contrary, studies by V.B. Semenyutin, et al [16] refute conclusions of some authors concerning relationship between a stenosis degree and a state of autoregulation. They estimated an autoregulation rate using the cross-spectral analysis of slow oscillations of systemic blood pressure and BFV in the ipsilateral MCA and failed to discover considerable dependence of autoregulation on a degree of ICA stenosis even in cases with critical lesions.…”

“…As for the study by V.B. Semenyutin, et al [16] homoor hyperechoic ASP of types I-II on the Gray-Weale scale were diagnosed in the majority of cases. Probably it was that very cause which did not allow the authors to reveal considerable difference in an autoregulation state and its dependence on an ASP type in symptomatic and asymptomatic cases by data of cross-spectral analysis.…”

“…The study by V.B. Semenyutin, et al [16] did not reveal reliable difference in indices of autoregulation depending on age, gender, a type of an atherosclerotic plaque (ASP), cormobid factors. It makes it possible to conclude that a type of a clinical course and a functional state are determined exactly by compensatory abilities of the system of collateral circulation.…”

“…V.B. Semenyutin, et al [16] demonstrated a positive effect of reconstructive operations on autoregulation and functional outcomes. However, it was watched only when initial preoperative indices of autoregulation on a lesion side were indicative of its impairment.…”