Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

Xiuyun Liu; Joseph Donnelly; Ken M. Brady; Kei Akiyoshi; Brian Bush; Raymond C. Koehler; Jennifer K. Lee; Charles W. Hogue; Marek Czosnyka; Peter Smielewski; Charles H. Brown

doi:10.1016/j.bja.2022.03.029

Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

Xiuyun Liu^*, Joseph Donnelly, Ken M. Brady, Kei Akiyoshi, Brian Bush, Raymond C. Koehler, Jennifer K. Lee, Charles W. Hogue, Marek Czosnyka, Peter Smielewski, Charles H. Brown^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

Background: Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery. Methods: Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality. Results: Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01–1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%. Conclusions: For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.

Original language	English (US)
Pages (from-to)	22-32
Number of pages	11
Journal	British journal of anaesthesia
Volume	129
Issue number	1
DOIs	https://doi.org/10.1016/j.bja.2022.03.029
State	Published - Jul 2022

Funding

CHB reported receiving grants from the National Institutes of Health (NIH) during the conduct of the study, and consulting for and participating in a data share with Medtronic. CWH reported receiving grants and personal fees for being a consultant and providing lectures for Medtronic/Covidien, Inc., being a consultant to Merck, Inc., and receiving grants from the NIH outside of the submitted work. JKL has received support from and been a paid consultant for Medtronic, and she is a paid consultant Edwards Life Sciences. JKL arrangements have been reviewed and approved by the Johns Hopkins University in accordance with its conflict of interest policies. Some methods used to measure and monitor autoregulation as described in this manuscript were patented by The Johns Hopkins University, listing KMB as a co-inventor. These patents are exclusively licensed to Medtronic Inc., and KMB received a portion of the licensing fee. PS and MC are authors of ICM+ software licensed by Cambridge Enterprise Ltd, UK, and have a financial interest in a part of licensing fee. US National Institutes of Health (K76 AG057020 to CHB, R01HL092259 to CWH; and NIH NINDS R01 NS107417 and R01 NS113921 to JKL).

Keywords

acute kidney injury
cardio pulmonary bypass
cerebral autoregulation
data visualisation
individualised blood pressure management
major morbidity, mortality
organ injury
postoperative outcome

ASJC Scopus subject areas

Anesthesiology and Pain Medicine

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Liu, X., Donnelly, J., Brady, K. M., Akiyoshi, K., Bush, B., Koehler, R. C., Lee, J. K., Hogue, C. W., Czosnyka, M., Smielewski, P., & Brown, C. H. (2022). Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery. British journal of anaesthesia, 129(1), 22-32. https://doi.org/10.1016/j.bja.2022.03.029

@article{f1c85c1e0eeb4d8dac38416f2170d629,

title = "Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery",

abstract = "Background: Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery. Methods: Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality. Results: Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01–1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%. Conclusions: For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.",

keywords = "acute kidney injury, cardio pulmonary bypass, cerebral autoregulation, data visualisation, individualised blood pressure management, major morbidity, mortality, organ injury, postoperative outcome",

author = "Xiuyun Liu and Joseph Donnelly and Brady, {Ken M.} and Kei Akiyoshi and Brian Bush and Koehler, {Raymond C.} and Lee, {Jennifer K.} and Hogue, {Charles W.} and Marek Czosnyka and Peter Smielewski and Brown, {Charles H.}",

note = "Publisher Copyright: {\textcopyright} 2022 British Journal of Anaesthesia",

year = "2022",

month = jul,

doi = "10.1016/j.bja.2022.03.029",

language = "English (US)",

volume = "129",

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journal = "British journal of anaesthesia",

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TY - JOUR

T1 - Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

AU - Liu, Xiuyun

AU - Donnelly, Joseph

AU - Brady, Ken M.

AU - Akiyoshi, Kei

AU - Bush, Brian

AU - Koehler, Raymond C.

AU - Lee, Jennifer K.

AU - Hogue, Charles W.

AU - Czosnyka, Marek

AU - Smielewski, Peter

AU - Brown, Charles H.

PY - 2022/7

Y1 - 2022/7

N2 - Background: Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery. Methods: Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality. Results: Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01–1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%. Conclusions: For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.

AB - Background: Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery. Methods: Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality. Results: Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01–1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%. Conclusions: For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.

KW - acute kidney injury

KW - cardio pulmonary bypass

KW - cerebral autoregulation

KW - data visualisation

KW - individualised blood pressure management

KW - major morbidity, mortality

KW - organ injury

KW - postoperative outcome

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ER -

Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

Abstract

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