Cerebral oxygen saturation as outcome predictor after transfemoral transcatheter aortic valve implantation

Cerebral oxygen saturation (ScO₂) can be measured non-invasively by near-infrared spectroscopy (NIRS) and correlates with cerebral perfusion. We investigated cerebral saturation during transfemoral transcatheter aortic valve implantation (TAVI) and its impact on outcome.

Cerebral oxygenation was measured continuously by NIRS in 173 analgo-sedated patients during transfemoral TAVI (female 47%, mean age 81 years) with self-expanding (39%) and balloon-expanding valves (61%). We investigated the periprocedural dynamics of cerebral oxygenation. Mean ScO₂ at baseline without oxygen supply was 60%. During rapid ventricular pacing, ScO₂ dropped significantly (before 64% vs. after 55%, p < 0.001). ScO₂ at baseline correlated positively with baseline left-ventricular ejection fraction (0.230, p < 0.006) and hemoglobin (0.327, p < 0.001), and inversely with EuroSCORE-II ( - 0.285, p < 0.001) and length of in-hospital stay ( - 0.229, p < 0.01). Patients with ScO2 < 56% despite oxygen supply at baseline had impaired 1 year survival (log-rank test p < 0.01) and prolonged in-hospital stay (p = 0.03). Furthermore, baseline ScO₂ was found to be a predictor for 1 year survival independent of age and sex (multivariable adjusted Cox regression, p = 0.020, hazard ratio (HR 0.94, 95% CI 0.90-0.99) and independent of overall perioperative risk estimated by EuroSCORE-II and hemoglobin (p = 0.03, HR 0.95, 95% CI 0.91-0.99).

Low baseline ScO₂ not responding to oxygen supply might act as a surrogate for impaired cardiopulmonary function and is associated with worse 1 year survival and prolonged in-hospital stay after transfemoral TAVI. ScO₂ monitoring is an easy to implement diagnostic tool to screen patients at risk with a potential preserved recovery and worse outcome after TAVI.