Abstract
Introduction
Stroke and transient ischemic attack (TIA) are important periprocedural cerebrovascular complications of transcatheter aortic valve implantation (TAVI). Regional cerebral O2 saturation is an indicator for cerebral perfusion and can be measured in real-time and noninvasively by near-infrared spectroscopy (NIRS). In this pilot study we evaluated the feasibility and utility of NIRS during TAVI.
Methods
Regional cerebral O2 saturation (rScO2, bihemispheric) was measured by near-infrared spectroscopy during 32 transfemoral TAVI procedures (female 56.3%, mean age 81.8 years). All patients received conscious sedation and O2-supplement if peripheral oxygen saturation (SpO2) was below 95%. Baseline rScO2 was measured at the beginning of the procedure, as well as before, during and 5min after rapid pacing for valve deployment.
Results
Mean preoperative mini mental state examination score was 26.5 points (theoretically max. 30 points, >24 points no severe cognitive impairment). Two-third of the patients (n=21) required oxygen supply (mean 4.0 l/min) during the TAVI procedure. Mean baseline rScO2 was 59.3% with no differences between both cerebral hemispheres (left 60.3% vs. right 58.7% p=0.23). Compared to baseline rScO2 and rScO2 assessed immediately before rapid passing, rScO2 dropped significantly during rapid pacing (59.3% vs. 51.8%, p<0.01 and 60.9% vs. 51.8%, p<0.01 respectively). Five minutes after rapid pacing rScO2 values had normalized again (post rapid pacing 60.9% vs. 51.8% during rapid pacing, p<0.01; baseline 59.3% vs. post rapid pacing 60.9%, p=0.51). Intraprocedural cerebrovascular events were observed in two cases. One patient developed a left-sided hemiplegia (stroke, later verified by cerebral CT scan) and one patient a transient tremor of the left upper extremity (TIA, new hemorrhagic or ischemic event ruled out by cerebral CT scan). In both cases we observed an abnormal sudden rScO2 decrement by the corresponding right hemispheric NIRS sensor (left-right hemisphere sensor: 60% vs. 44% and 63% vs. 48% respectively).
Conclusion
Regional cerebral O2 saturation, an indicator for cerebral perfusion, decreases significantly during rapid pacing of TAVI procedure. Furthermore, rScO2 measurement by NIRS may be helpful to detect cerebrovascular complications early during TAVI procedure.
Time-domain near-infrared spectroscopy in acute ischemic stroke patients
