Srichawla BS, Garcia-Dominguez MA. Regional dynamic cerebral autoregulation across anterior and posterior circulatory territories: A detailed exploration and its clinical implications. World J Crit Care Med 2024; 13(4): 97149 [DOI: 10.5492/wjccm.v13.i4.97149]
Corresponding Author of This Article
Bahadar S Srichawla, DO, MS, Staff Physician, Department of Neurology, University of Massachusetts Chan Medical School, 55 Lake Ave N, Worcester, MA 01655, United States. bahadar.srichawla@umassmed.edu
Research Domain of This Article
Critical Care Medicine
Article-Type of This Article
Minireviews
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Crit Care Med. Dec 9, 2024; 13(4): 97149 Published online Dec 9, 2024. doi: 10.5492/wjccm.v13.i4.97149
Regional dynamic cerebral autoregulation across anterior and posterior circulatory territories: A detailed exploration and its clinical implications
Bahadar S Srichawla, Maria A Garcia-Dominguez
Bahadar S Srichawla, Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, United States
Maria A Garcia-Dominguez, Department of Neurology, University of Massachusetts, Worcester, MA 01655, United States
Author contributions: Srichawla BS contributed to intellectual verification, writing and editing, project leadership; Garcia-Dominguez MA contributed to writing and editing.
Conflict-of-interest statement: The authors report no conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Bahadar S Srichawla, DO, MS, Staff Physician, Department of Neurology, University of Massachusetts Chan Medical School, 55 Lake Ave N, Worcester, MA 01655, United States. bahadar.srichawla@umassmed.edu
Received: May 24, 2024 Revised: September 24, 2024 Accepted: October 10, 2024 Published online: December 9, 2024 Processing time: 160 Days and 7.7 Hours
Abstract
Cerebral autoregulation (CA) is the mechanism that maintains stable cerebral blood flow (CBF) despite fluctuations in systemic blood pressure, crucial for brain homeostasis. Recent evidence highlights distinct regional variations in CA between the anterior (carotid) and posterior (vertebrobasilar) circulations. Non-invasive neuromonitoring techniques, such as transcranial Doppler, transfer function analysis, and near-infrared spectroscopy, facilitate the dynamic assessment of CBF and autoregulation. Studies indicate a robust autoregulatory capacity in the anterior circulation, characterized by rapid adjustments in vascular resistance. On the contrary, the posterior circulation, mainly supplied by the vertebral arteries, may have a lower autoregulatory capacity. in acute brain injuries such as intracerebral and subarachnoid hemorrhage, and traumatic brain injuries, dynamic CA can be significantly altered in the posterior circulation. Proposed physiological mechanisms of impaired CA in the posterior circulation include: (1) Decreased sympathetic innervation of the vasculature impairing compensatory vasoreactivity; (2) Endothelial dysfunction; (3) Increased cerebral metabolic rate of oxygen consumption within the visual cortex causing CBF-metabolism (i.e., neurovascular) uncoupling; and (4) Impaired blood-brain barrier integrity leading to impaired astrocytic mediated release of vasoactive substances (e.g. nitric oxide, potassium, and calcium ions). Furthermore, more research is needed on the effects of collateral circulation, as well as the circle of Willis variants, such as the fetal-type posterior cerebral artery, on dynamic CA. Improving our understanding of these mechanisms is crucial to improving the diagnosis, prognosis, and management of various cerebrovascular disorders.
Core Tip: Cerebral autoregulation (CA) maintains stable cerebral blood flow (CBF) despite systemic blood pressure changes. Recent evidence highlights regional CA variations between anterior and posterior circulations. Non-invasive neuromonitoring techniques like transcranial Doppler, transfer function analysis, and near-infrared spectroscopy facilitate dynamic CBF assessment. Studies show robust autoregulation in the anterior circulation but lower capacity in the posterior circulation. Impaired CA in the posterior circulation, especially during acute brain injuries, may result from decreased sympathetic innervation, endothelial dysfunction, increased metabolic demands, and impaired blood-brain barrier integrity. Understanding these mechanisms is vital for improving cerebrovascular disorder management.
