Covert stroke after non-cardiac surgery: a prospective cohort study.

Mrkobrada, M; Hill, M D; Chan, M T V; Sigamani, A; Cowan, D; Kurz, A; Sessler, D I; Jacka, M; Graham, M; Dasgupta, M; Dunlop, V; Emery, D J; Gulka, I; Guyatt, G; Heels-Ansdell, D; Murkin, J; Pettit, S; Sahlas, D J; Sharma, M; Sharma, M; Srinathan, S; St John, P; Tsai, S; Gelb, A W; O'Donnell, M; Siu, D; Chiu, P W Y; Sharath, V; George, A; Devereaux, P J

BACKGROUND Overt stroke after non-cardiac surgery has a substantial impact on the duration and quality of life. Covert stroke in the non-surgical setting is much more common than overt stroke and is associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after non-cardiac, non-carotid artery surgery. METHODS We undertook a prospective, international cohort study to determine the incidence of covert stroke after non-cardiac, non-carotid artery surgery. Eligible patients were ≥65 yr of age and were admitted to hospital for at least three nights after non-cardiac, non-carotid artery surgery. Patients underwent a brain magnetic resonance study between postoperative days 3 and 10. The main outcome was the incidence of perioperative covert stroke. RESULTS We enrolled a total of 100 patients from six centres in four countries. The incidence of perioperative covert stroke was 10.0% (10/100 patients, 95% confidence interval 5.5-17.4%). Five of the six centres that enrolled patients reported an incident covert stroke, and covert stroke was found in patients undergoing major general (3/27), major orthopaedic (3/41), major urological or gynaecological (3/22), and low-risk surgery (1/12). CONCLUSIONS This international multicentre study suggests that 1 in 10 patients ≥65 yr of age experiences a perioperative covert stroke. A larger study is required to determine the impact of perioperative covert stroke on patient-important outcomes. CLINICAL TRIAL REGISTRATION NCT01369537.