Improvement of cognitive test performance in patients undergoing primary CABG and other CPB-assisted cardiac procedures

Cardiac surgical procedures assisted by cardiopulmonary bypass (CPB) impair cognitive functions. Several studies, however, showed that cognitive functions were unaffected in patients undergoing either primary coronary artery bypass grafting (CABG) or more complex surgery assisted by CPB. Therefore, we conducted a straightforward study to compare patient groups who differed significantly in terms of risk factors such as prolonged CPB times. Consecutive patients (n = 54) were included, undergoing either non-primary CABG, e.g. valve and/or CABG, (n = 30) or primary CABG (n = 24), assisted by CPB. Cognitive function was determined pre-operatively on the day of hospital admission, and post-operatively after one and six months using the Cognitive Drug Research computerized assessment battery. Data from the fourteen individual task variables were summarized in four composite scores: Power of Attention (PoA), Continuity of Attention (CoA), Quality of Episodic Memory (QoEM), and Speed of Memory (SoM). In the non-primary CABG patients, both CoA and QoEM improved after 1 month (p = 0.001 and p = 0.016, respectively), whereas, after 6 months, CoA (p = 0.002), QoEM (p = 0.002) and SoM (p <0.001) were improved. In primary CABG patients, CoA improved at one month after surgery (p = 0.002) and, after six months, not only CoA (p = 0.003), but also QoEM and SoM were improved (p = 0.001 and p = 0.030, respectively). The test performance was similar in non-primary and primary CABG patients after surgery. Our present study shows a post-operative improvement of cognitive composite scores after cardiac surgery assisted by CPB in both non-primary CABG and in primary CABG patients