Regional Cerebral Blood Flow Increase After Transcatheter Aortic Valve Replacement Is Related to Cardiac Output but Is Not Associated with Delirium: An Observational Cohort Study Using Transcranial Indocyanine Green Dye Dilution Technique

TL;DR

This study found that increased cerebral blood flow after heart valve replacement is linked to improved heart output but not to delirium.

Contribution

The study introduces a novel observational approach using indocyanine green dye to assess cerebral blood flow changes post-TAVR and their relation to delirium.

Findings

Cardiac output increased by 44% after TAVR, which was associated with increased cerebral blood flow.

Cerebral blood flow changes were not significantly linked to postoperative delirium.

Decreased cerebral oxygenation and increased deoxygenated hemoglobin were associated with delirium.

Abstract

Background: Despite the success of transcatheter aortic valve repair (TAVR) over the past years, its impact on global and cerebral hemodynamics remains largely unexplored. Changes in cerebral blood flow may be associated with delirium, which may occur in 26 to 29% of cases. We aimed to examine the relationships between global hemodynamic parameters and cerebral parameters in patients who underwent TAVR and their impact on postinterventional delirium. Methods: Patients scheduled for TAVR were enrolled after obtaining written informed consent. Patients received light sedation according to standard procedures. Cerebral blood flow (CBF) was measured with a noninvasive near-infrared spectroscopy-based method using intravenous indocyanine green injection. CBF measurements were taken at the beginning of the TAVR procedure and after the valve was in place. Patients were screened for delirium using CAM-ICU and NuDESC tests before and after intervention. Results: A total of 52 of 60 patients remained for analysis. Thirteen patients (25%) developed delirium. Mean arterial pressure (MAP) remained unchanged, while cardiac output increased after TAVR by 44%. CBF also increased after TAVR. No significant difference was observed in CBF changes between the groups with and without delirium. A linear mixed model analysis revealed a linear relationship between CO and CBF but not between MAP and CBF. In an exploratory analysis, decreased cerebral oxygenation and increased deoxygenated hemoglobin, as measured by NIRS after TAVR, were associated with delirium. Conclusions: The results confirm that CO is an independent factor in CBF, while CBF changes per se are not linked to delirium. However, we found a mismatch between CBF and regional cerebral parameters, which may reflect cerebral metabolism and its relation to the development of delirium. This remains to be confirmed by further studies.

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