Long-term changes in cerebrovascular reactivity following EC-IC bypass for intracranial steno-occlusive disease

Casey Rosen; Larissa McKetton; Jeremy Russell; Kevin Sam; Julien Poublanc; Adrian Crawley; Jay S Han; Olivia Sobczyk; James Duffin; Danny M Mandell; Michael Tymianski; Joseph A Fisher; David J Mikulis; Lashmi Venkatraghavan

doi:10.1016/j.jocn.2018.06.009

Long-term changes in cerebrovascular reactivity following EC-IC bypass for intracranial steno-occlusive disease

J Clin Neurosci. 2018 Aug:54:77-82. doi: 10.1016/j.jocn.2018.06.009. Epub 2018 Jun 12.

Authors

Affiliations

¹ Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.
² Division of Neurosurgery, University Health Network, University of Toronto, Toronto, Ontario, Canada.
³ Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada; Department of Physiology, The University of Toronto, Toronto, ON, Canada.
⁴ Department of Anaesthesia, University Health Network, Toronto, ON, Canada.
⁵ Institute of Medical Sciences, The University of Toronto, Toronto, ON, Canada.
⁶ Department of Physiology, The University of Toronto, Toronto, ON, Canada; Department of Anaesthesia, University Health Network, Toronto, ON, Canada.
⁷ Department of Physiology, The University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, The University of Toronto, Toronto, ON, Canada; Department of Anaesthesia, University Health Network, Toronto, ON, Canada.
⁸ Department of Physiology, The University of Toronto, Toronto, ON, Canada.
⁹ Department of Anaesthesia, University Health Network, Toronto, ON, Canada. Electronic address: Lashmi.Venkatraghavan@uhn.ca.

PMID: 29907385
DOI: 10.1016/j.jocn.2018.06.009

Abstract

The purpose of this retrospective observational study is to investigate the long-term changes in cerebrovascular reactivity (CVR) as a measure of cerebral hemodynamics in patients with intracranial steno-occlusive disease (IC-SOD) after they have undergone an Extracranial-intracranial (EC-IC) bypass. Twenty-six patients suffering from IC-SOD were selected from our CVR database. Nineteen patients underwent unilateral and 7 underwent bilateral revascularization. CVR measurements were done using BOLD-MRI and precisely controlled CO2 and expressed as ΔBOLD (%)/Δ P_ETCO₂ (mmHg). Trends in CVR over time were compared in both vascularized and non-vascularized hemispheres. Repeated measures analysis of variance with Greenhouse-Geisser correction was used to determine CVR changes within the grey matter MCA for longitudinal assessments. Overall, re-vascularized hemisphere showed a significant increase in CVR at the first follow-up, followed by a slight decrease at the second follow-up that significantly increased compared to the pre-bypass. However, the changes in the postoperative CVR were quite variable across the patients. Similar variability was seen in subsequent follow-ups, with a slight overall decline in the long term CVR as compared with first post-operative CVR. Our study demonstrates that EC-IC bypass has a beneficial long-term effect on cerebral hemodynamics and this effect varies between patients probably due to the variability in the underlying vascular pattern receiving the bypass. Hence, in the postoperative follow-up of patients routine functional imaging to monitor cerebral hemodynamics may be useful as the risk of stroke and cognitive decline remain present with impaired CVR.

Keywords: Blood-oxygen-level dependent magnetic resonance imaging; Cerebrovascular reactivity; Extracranial-intracranial bypass; Steno occlusive disease.

Publication types

Observational Study

MeSH terms

Adolescent
Adult
Aged
Brain / blood supply*
Cerebral Revascularization / methods*
Cerebrovascular Circulation / physiology*
Cerebrovascular Disorders / physiopathology*
Cerebrovascular Disorders / surgery*
Female
Hemodynamics
Humans
Magnetic Resonance Imaging / methods
Male
Middle Aged
Retrospective Studies