Abstract TMP9: The Neurovision Pilot Study: Non-cardiac Surgery Carries A Significant Risk Of Acute Covert Stroke

Introduction: 200 million patients worldwide undergo noncardiac surgery every year. Overt stroke is a serious complication of noncardiac surgery with significant impact on duration and quality of life. In the non-surgical population, covert stroke is 10 times more common then overt stroke and is associated with an increased risk of dementia and cognitive decline. The epidemiology of covert stroke after noncardiac surgery is not well characterized. Study Objectives: We undertook a pilot study to determine the incidence of covert stroke after noncardiac surgery. Methods: This was a prospective, international cohort study. Eligible patients were 65 years or older, and were admitted to hospital for at least one night after noncardiac surgery. A sampling strategy was employed to ensure a representative surgical population. Study personnel recorded clinical characteristics and the incidence of perioperative adverse events. We also assessed neurocognitive function, physical function and quality of life before surgery and 30 days after surgery. Patients underwent a brain magnetic resonance imaging (MRI) study between postoperative days 3 and 10. Fluid attenuated inversion recovery, gradient echo, T2 and diffusion-weighted imaging MRI sequences were obtained. Results: A total of 70 patients from three centres were enrolled in this study. The incidence of covert stroke was 11.4% (8/70 patients, 95% CI 5.9% to 21.0%). The single overt stroke was diagnosed after the research MRI study demonstrated findings of an acute stroke. All three centres experienced a similar prevalence of covert stroke (range 8.0% to 15.0%), and covert stroke was found in patients undergoing general (4/16), orthopedic (3/36), and urological/gynecological surgery (2/8). Conclusions: There is a significant risk of covert stroke after all types of noncardiac surgery. Given that globally 200 million adults undergoing major noncardiac surgery every year, postoperative covert stroke may be responsible for a significant proportion of small vessel cerebral ischemic disease in the overall population. A large study is needed to characterize the impact of postoperative covert stroke on clinically meaningful outcomes.