<qa>  What is the main barrier to TAVI?On the other hand, beside frailty status the main barrier to TAVI is the risk of neurological impairment. The TAVI candidate patients have specific central nervous system CNS issues because of neurobiological changes of aging, e.g. decreased brain weight and volume, decreased neurotransmitter system function, decreased neuronal gene expression and Alzheimer type changes 8. Neurological injury and impairment in TAVI can occur as cerebrovascular event CVE andor neurocognitive dysfunction. Both forms might be clinically apparent and detected, clinically apparent but undetected and clinically silent and undetected. The two neurocognitive dysfunctions - post-operative delirium POD and post-operative cognitive dysfunction POCD - most cases remain undetected although clinically could be apparent or silent 9. POD is defined by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition DSM-5. POCD is defined by Kappetein et al., as deterioration of intellectual function presenting as impaired memory or concentration presenting with temporal association to surgery 9, 10. The neurological injury can be observed andor detected by neuroimaging techniques and cognitive trajectories. Some insult caused by TAVI might remain in the clinically silent area and might be observed only as slight neurocognitive dysfunction. Analization of the incidence and underlying etiology of the neurological events may lead to identification of recently non-recognized techniques or neuroprotective strategies, devices. The most elevated incidence of CVEs is within 24 hours of TAVI. This risk of further events might be high for up to two months 11. One fifth of health-related quality of life HRQOL is characterized by cognitive functions. Studies and reports on cognitive, psychiatric, andor neurological events following TAVI have focused on major and well-marked complications, e.g., stroke, TIA, and post-operative delirium 12. Meantime TAVI is associated with a high incidence 73-84 of silent cerebral embolism as detected by diffusion-weighted MRI 13. 