[Postoperative cognitive dysfunction in off-pump versus on-pump coronary artery bypass surgery]

Patients referred for coronary artery bypass grafting (CABG) are older and more likely to have extensive vascular diseases than those referred for such procedures in the past. Undiagnosed cerebral small vessel diseases (SVD), such as lacunar infarctions or white matter lesions, and dementia are common. Postoperative cognitive dysfunction (POCD) remains a major concern in these elderly patients. POCD is caused by cerebral emboli, hypoperfusion, and inflammation attributed largely to the use of cardiopulmonary bypass. Off-pump CABG is a surgical strategy proposed to decrease the risk of POCD. Although some researchers have found that off-pump CABG is associated with improved cognitive outcome in the early postoperative period, many studies have shown no difference at any time points. Consequently, efforts to reduce the incidence of POCD are focusing on patient-related rather than procedure-related factors. Surgical procedures could exacerbate neuroinflammation and accelerate cognitive dysfunction, especially in patients with SVD and dementia. Mild cognitive impairment may serve as a surrogate marker for underlying SVD or dementia. Preoperative cerebrovascular evaluation, such as MRI, MRA, or cervical ultrasound, and cognitive screening may be effective to identify high-risk patients, making it possible to individualize surgical approaches aimed at reducing POCD.