Non-invasive cerebral oxygenation reflects mixed venous oxygen saturation during the varying haemodynamic conditions in patients undergoing transapical transcatheter aortic valve implantation

Transapical transcatheter aortic valve implantation (TA-TAVI) is increasingly used to treat aortic valve stenosis in high-risk patients. Mixed venous oxygen saturation (SvO ₂) is still the 'gold standard' for the determination of the systemic oxygen delivery to consumption ratio in cardiac surgery patients. Recent data suggest that regional cerebral oxygen saturation (rScO ₂) determined by near-infrared spectroscopy is closely related to SvO ₂. The present study compares rScO ₂ and SvO ₂ in patients undergoing TA-TAVI. n = 20 cardiac surgery patients scheduled for TA-TAVI were enrolled in this prospective observational study. SvO ₂ and rScO ₂ were determined at predefined time points during the procedure. Correlation and Bland-Altman analysis of the complete data set showed a correlation coefficient of r2 = 0.7 between rScO ₂ and SvO ₂ (P < 0.0001), a mean difference (bias) of 5.8 with limits of agreement (1.96 SD) of -6.8 to 18.3% and a percentage error of 17.5%. At all predefined time points correlation was moderate (r2 = 0.50) to close (r = 0.84), and the percentage error was <24%. RScO2 determined by near-infrared spectroscopy is correlated to SvO ₂ during varying haemodynamic conditions in patients undergoing TA-TAVI. This suggests that rScO ₂ is reflective not only of the cerebral, but also of the systemic oxygen balance.