Research Long-term Cognitive Impairment After Off-Pump Versus On-Pump Cardiac Surgery: Involved Risk Factors

Off-pump cardiac surgery was developed to reduce perioperative complications associated with the use of cardiopulmonary bypass (“on-pump”), including neurologic injury. Postoperative cognitive impairment (PCI) is considered to be a relevant neurologic complication after cardiac surgery. ^,  Cardiopulmonary bypass and nonspecific surgery factors have been related to PCI but the evidence is inconclusive. ^{,  ,}  PCI is defined as a decline in performance on neuropsychological tests relative to preoperative levels and several cognitive domains could be affected. ^{,  ,}  Its incidence range varies from 4% to 80% and it may remain months or years after surgery. ^{,  ,}  The objectives of this study were to assess long-term cognitive impairment differences after off-pump and on-pump cardiac surgery and to identify involved risk factors. We prospectively and sequentially included 70 patients, 34 (48.6%) scheduled for elective on-pump cardiac surgery (concomitant aortic valve replacement and coronary artery bypass grafting) and 36 (51.4%) for elective off-pump cardiac surgery (coronary artery bypass grafting). Follow-up of all patients was standardized with recording sociodemographic, clinical, and operative-anesthetics data, and a multidomain neurocognitive evaluation with a battery of 6 age- and education-adjusted neuropsychological tests was performed preoperatively and at 1, 6, and 12 months. The presence of cognitive impairment was defined by a score deterioration in the performance of any test ≥1.5 SD with respect to conormative data and PCI as its significant worsening after surgery related to preoperative levels. The presence of cognitive impairment after surgery significantly increased in both on-pump and off-pump groups (P < .001 and P < .01, respectively), reaching the maximum cognitive impairment at 6 months, and remained at 12 months. PCI was significantly greater among patients of the on-pump group at 6 and 12 months (Figure 1). Before surgery and at 1-month follow-up, no significant differences were found between groups. Attention-executive function, memory, and verbal fluency were the cognitive domain affected. Nonsignificant change was observed in visuospatial perception. The independent predictors of PCI identified were specific procedural factors as the mean levels of intraoperative oxygen saturation lower than 90% (odds ratio [OR]: 9.9; 95% confidence interval [95% CI]: 5.8-19.8; P < .001) and cardiopulmonary bypass time greater than 160 minutes (OR: 4.1; 95% CI: 1.8-7.1; P < .001), and cardiovascular risk factors as the history of smoking (OR: 7.9; 95% CI: 2.7-10.4; P < .001), presence of heart failure (OR: 3.2; 95% CI: 1.6-6.0; P < .05), left ventricular hypertrophy (OR: 2.8; 95% CI: 1.5-5.7; P < .05), diabetes mellitus (OR: 1.6; 95% CI: 1.2-3.3; P < .05), 3-vessel coronary artery disease (OR: 1.6; 95% CI: 1.1-3.1; P < .05), and peripheral arteriopathy (OR: 1.2; 95% CI: 1.1-3.1; P < .05).