Younger age is associated with greater early neurocognitive decline postcardiopulmonary bypass.

Abstract

To examine the effect of aging on postoperative neurocognitive decline (NCD) in cardiac surgery patients. Patients undergoing coronary artery bypass graft or open aortic valve replacement were administered the Repeatable Battery for the Assessment of Neuropsychological Status at preoperative, postoperative day (POD) 4, and 1month. Blood samples were collected at preoperative, 6hours postoperative, and POD 4. Plasma interleukin (IL)-6, tumor necrosis factor-α, and C-reactive protein (CRP) levels were quantified. Quality of life was measured with the 12-Item Short Form Health Survey. Data were analyzed using paired ratio and unpaired t tests with Welch's correction, and linear regression for cytokine levels. NCD occurred in 15 patients (N=33, 45.5%). Dichotomized at age extremes (<60years; ≥75years), youngest patients had greater preoperative scores (P=.02) with lower scores by POD 4 (P=.03). There was no NCD in the oldest patients, and scores were not different between age groups on POD 4 (P=.08). Regression at 1month showed NCD scores again declined by age (n=15), with younger scores returning toward baseline (P=.008). Regression analyses showed decline by age at 6hours postoperative and POD 4 in plasma CRP levels (P=.05 6hours, P=.02 POD 4). Dichotomizing IL-6 levels by age (<70years, ≥70years) demonstrated that levels were greater in younger versus older patients at 6hours postoperative (P=.03), but not on POD 4. Younger patients tend to have better cognitive scores before surgery but scores at POD 4 are similar to those of older patients, with this trend disappearing at 1month. IL-6 and CRP upregulation is greater in younger patients, suggesting that a robust perioperative inflammatory response may be associated with reduction in neurocognitive function, and this may be greater in younger versus older patients.