Background Aortic valve replacement (AVR) has been associated with postoperative transient ischaemic attack, stroke and neurocognitive decline. Transcatheter aortic valve implantation (TAVI) has been in development for nearly a decade for patients not suitable for surgery. Cognitive change after TAVI is not yet clear. We set out to examine the effects of cognitive dysfunction on quality of life (QoL) following TAVI and AVR. Methods 88 consecutive high risk patients with severe aortic stenosis and discussed at an MDT who underwent TAVI (n=38) or AVR (n=50) were studied. Transcranial Doppler ultrasound (TCD) examinations were recorded for all patients. A comprehensive neurocognitive assessment was performed on patients at baseline and 3 months using a battery of cognitive tests. QoL analysis was completed on patients at baseline, 3, 6 and 12 months using the Short Form 36 (SF-36v2™) with an additional propensity matched group analysed. Results Cerebral embolic load had a mean of 271 (range 160-309) in AVR patients and 280 (range 186- 326) in TAVI patients. Duration of cardiopulmonary bypass (CPB) for AVR and valve deployment for TAVI, were associated with the highest number of embolic signals (ES) recorded (mean 106 and 103 respectively). AVR and TAVI patients had a significant decrease in processing speed (p=0.04 and p=0.04). The AVR group showed a cognitive decline in visual planning and short term memory (p=0.02), TAVI patients in new learning and verbal memory (p=0.02, p=0.03). Both procedures resulted in an increase in patient QoL with no difference in improvements between AVR and TAVI patients in the propensity matched group. Conclusion ES load was recorded for AVR and TAVI, with significantly more ES for duration of bypass in AVR and deployment of the valve in TAVI. AVR and TAVI patients had mild post-operative cognitive changes with both having a significantly decreased processing speed score at 3 months follow up. QoL of patients undergoing AVR and TAVI increased post-procedure at 3, 6 and 12 months. Patients improved equally in terms of QoL in the propensity matched group of AVR and TAVI patients.