Incidence and impact of silent brain lesions after coronary artery bypass grafting

Objective: Silent brain lesions are known to occur after coronary artery bypass grafting (CABG). The aim of this study was to seek the incidence rate, the influence of procedures, and their impact on the postoperative course. Methods: From July 2016 to April 2018, 104 consecutive patients undergoing elective and isolated first-time CABG (65 off-pump and 39 on-pump) were enrolled. New brain lesions were evaluated by brain magnetic resonance imaging both before and after CABG. Postoperative outcomes, including cognitive function, were compared between patients with and without brain lesions. Results: The overall incidence of new brain lesions was 20.1% (21/104). Excluding one symptomatic stroke case, silent brain lesions were revealed in the remaining patients. The percentage of on-pump CABG (61.9% [13/21] vs 31.3% [26/83], P = .019) and aortic clamp (52.4% [11/21] vs 24.1% [20/83], P = .014) were significantly greater in patients with brain lesions. Brain lesions were observed in 12.3 % and 15.8 % of patients in the off-pump and anaortic CABG. The Katz Index of Independence in Activities of Daily Living was significantly lower in patients with brain lesions (from 5.8 +/- 0.9 to 5.4 +/- 1.2 vs from 5.9 +/- 0.5 to 5.9 +/- 0.6, P = .013). In patients with new lesions, postoperative cognitive dysfunction (POCD) was observed only in multiple lesions, and the maximum size was significantly greater in patients with POCD. Conclusions: Magnetic resonance imaging of the brain frequently detected postoperative silent brain lesions after CABG in off-pump and aorta non-touch groups. Multiple and larger new brain lesions were associated with the development of POCD.