Pre-operative mild cognitive dysfunction predicts risk for post-operative delirium after elective cardiac surgery.
OBJECTIVE
To identify pre-operative risk factors for delirium in patients undergoing elective cardiac surgery, using clearly defined diagnostic criteria for delirium, and a thorough clinical assessment.


METHODS
The incidence of post-operative delirium in 107 patients >or=60 years undergoing elective cardiac surgery was calculated. None of the patients included suffered from dementia. Pre-operative cognitive function in all patients was assessed using the Mini Mental State Examination (MMSE) and post-operative delirium was diagnosed using the Confusion Assessment Method (CAM). Post-operative clinical and cognitive assessments were carried out for all patients.


RESULTS
Twenty-five patients (23.4%) developed delirium post-operatively. Clinical parameters, including age, gender, co-morbidities, medications, and peri-operative parameters, were similar in patients with and without post-operative delirium. Patients with pre-operative subjective memory complaints and lower MMSE scores, undergoing valve operation or valve + coronary artery bypass grafting (CABG), exhibited an increased risk of developing post-operative delirium. Additionally, delirious patients had a significant decline in post-operative MMSE score compared with the non-delirious ones.


CONCLUSIONS
The main pre-operative risk factors for post-operative delirium after elective cardiac operations were subjective memory complaints, mild cognitive impairment, and type of cardiac surgery, such as valve procedures. This study suggests that cognitive evaluation should be included in pre-operative assessment.
Veliz-Reissmüller
Graciela
G
Department of Neurobiology, Caring Sciences and Society, Division of Clinical Geriatrics, Karolinska Institutet, Karolinska University Hospital, S-141 86 Stockholm, Sweden.
Agüero Torres
Hedda
H
van der Linden
Jan
J
Lindblom
Dan
D
Eriksdotter Jönhagen
Maria
M
D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D003072:Cognition Disorders / Q000150:complications*; D001026:Coronary Artery Bypass / Q000009:adverse effects; D003693:Delirium / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000209:etiology*; D012307:Risk Factors