Small ischemic brain lesions after cardiac valve replacement detected by diffusion-weighted magnetic resonance imaging: relation to neurocognitive function.
OBJECTIVE
Following coronary artery bypass graft surgery, some studies using magnetic resonance imaging (MRI) have demonstrated new small ischemic brain lesions in patients without apparent neurological deficits. We aimed to prospectively evaluate brain injury after cardiac valve replacement using MRI and to determine the relationship to neurocognitive function.


METHODS
Thirty patients with a mean age of 64.9+/-9.8 years (range, 32-82, 12 female) receiving cardiac valve replacement (aortic valve replacement [AVR], n = 24; mitral valve replacement [MVR], n = 2; AVR and MVR, n = 2; AVR and mitral valve repair, n = 2) were investigated. Study protocol included neurological examination, comprehensive neuropsychological assessment and diffusion-weighted (DW) MRI. The investigations were performed before surgery and 5 days and 4 months after surgery.


RESULTS
Postoperative DW MRI detected new focal brain lesions in 14 patients (47%). No patient revealed a focal neurological deficit. Six patients (43%) had multiple (> or = 3) lesions (range, 1-7). Lesion volume ranged from 50-500 mm3 except 1 territorial infarct of 1900 mm3. Of a total of 41 lesions, 27 (66%) were located in the right hemisphere and 32 in a subcortical location. By 5 days postoperatively, significant neurocognitive decline was observed in 5 of 13 tests affecting memory, attention and rate of information processing. By 4 months, dysfunction had recovered in all cognitive areas. The presence of new ischemic lesions was not associated with neurocognitive decline at discharge. There was also no significant correlation between clinical and operative variables and the presence of new DW lesions or neuropsychological outcome.


CONCLUSIONS
Following cardiac valve replacement, new small ischemic brain lesions were detected by diffusion-weighted MRI. Neurocognitive decline was present early after operation, but resolved within 4 months. A correlation of new ischemic lesions to postoperative cognitive dysfunction or clinical variables was not found.
Knipp
Stephan C
SC
Department of Thoracic and Cardiovascular Surgery, West German Heart Centre, University Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany. stephan.knipp@uni-essen.de
Matatko
Nadine
N
Schlamann
Marc
M
Wilhelm
Hans
H
Thielmann
Matthias
M
Forsting
Michael
M
Diener
Hans C
HC
Jakob
Heinz
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000523:psychology; D003072:Cognition Disorders / Q000209:etiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006349:Heart Valve Diseases / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology; D011446:Prospective Studies