Incidence and Mechanisms of Cerebral Ischemia After Transcatheter Aortic Valve Implantation Compared With Surgical Aortic Valve Replacement

Background. The most likely mechanisms of neurologic injury after transcatheter aortic valve implantation (TAVI) and aortic valve replacement (AVR) are cerebral embolization and hypoperfusion. We set out to determine potential mechanisms of neurologic injury after TAVI compared with AVR. Methods. One hundred twenty-seven consecutive high-risk patients with severe aortic stenosis (AS) who underwent TAVI (n = 85) or AVR (n = 42) were studied. Transcranial Doppler ultrasound (TCD), cerebral oximetry, diffusion-weighted magnetic resonance imaging (DW-MRI) (before, 6 days, and 3 months after procedure), and neurocognitive assessment before and at 3 months were performed. Results. Neurologic injury was not significantly different between TAVI and AVR at 1 (1.1% vs 2.2%, p = 0.25) and 3 months (4.7% vs 2.2%, p = 1). At 3 months, overall cognitive score was higher in AVR compared with TAVI when adjusted for baseline score; the estimated difference between groups was 0.63 (95% confidence interval 0.87% to 1.17%; p = 0.02). Cerebral embolic load was 212 (123 to 344) during AVR and 134 (76 to 244) during TAVI (p = 0.07). Cerebral oxygen desaturation during AVR (7.56 +/- 2.16) was higher compared with TAVI (5.93 +/- 2.47) (p < 0.01). Ischemic lesions measured by DW-MRI occurred in 76% of TAVI and 71% of AVR patients at 6 days (p = 0.69) and 63% and 39% at 3 months (p=0.11). No significant association was found between cerebral emboli, cerebral oxygen desaturation, brain ischemic lesions, and general cognitive score. Conclusions. At 3 months follow-up, overall cognitive score was higher in AVR compared with TAVI, adjusted for baseline score. However, there was no difference in cerebral embolic load, ischemic lesions, and oxygen desaturation. (C) 2015 by The Society of Thoracic Surgeons