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Improving Cognitive Health after Cardiac Surgery

Bowden, T (2023). Improving Cognitive Health after Cardiac Surgery. (Unpublished Doctoral thesis, City, University of London)



Over 31,000 adults undergo cardiac surgery annually in the United Kingdom. While operative mortality is low, 30% to 80% of patients experience cognitive impairment after surgery. Postoperative cognitive dysfunction (POCD) is a decline in objectively measured postoperative cognitive function compared to function assessed before surgery. The underlying causes and pathophysiology of POCD are poorly understood. Further, definitive treatments for POCD are lacking. Significant variation in methods and outcomes limits the generalisability of existing work investigating cognitive interventions in cardiac surgical patients.


The purpose of this research was to develop and test the feasibility of an intervention designed to improve cognitive function in patients recovering after cardiac surgery. The aims were to identify the predictors of POCD, examine the effectiveness of cognitive interventions after general anaesthesia, and to test the feasibility and acceptability of the intervention.


This programme of work had two phases: 1) the conduct of two systematic reviews, and 2) feasibility and acceptability testing of the intervention. The systematic reviews were performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Based on phase 1 results, an existing intervention was adapted to the postoperative cardiac surgical population. In phase 2, a single-arm non-blinded study was conducted to evaluate the feasibility and acceptability of home-based computerised cognitive training after cardiac surgery.


In the first systematic review, 61 independent predictors (45 preoperative and 16 postoperative) were identified as significant in at least one study, though these were reported inconsistently across studies. Age was the most common predictor of cognitive function.

In the second systematic review, computerised cognitive interventions (n=4 [44.4%]) and traditional cognitive interventions (n=5 [55.6%]) were used to improve cognitive function. Use of cognitive interventions demonstrated efficacy in improving cognitive function after general anaesthesia, particularly those targeting memory. Acceptability of cognitive interventions was rarely reported in the research.

Twenty-nine patients enrolled in the FACCT study. Home-based computerised cognitive training was feasible for recruitment rate (60.8%) and acceptable (94.1% of those who completed the Acceptability Questionnaire). Elements that did not meet the pre-defined targets included retention (58.6%) and adherence (31.0%).


This study provides a unique contribution to improving POCD in postoperative cardiac surgical patients, specifically evaluating intervention feasibility and acceptability. A trial examining home-based computerised cognitive training appears feasible and acceptable to patients, although strategies to improve retention and adherence are needed before proceeding to an efficacy study.

Publication Type: Thesis (Doctoral)
Subjects: B Philosophy. Psychology. Religion > BF Psychology
R Medicine > RD Surgery
Departments: School of Health & Psychological Sciences > Psychology
School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses
Doctoral Theses
[thumbnail of Volume 1] Text (Volume 1) - Accepted Version
This document is not freely accessible until 31 January 2027 due to copyright restrictions.

[thumbnail of Volume 2] Text (Volume 2) - Accepted Version
This document is not freely accessible until 31 January 2027 due to copyright restrictions.


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