Assessment of cognitive impairments following coronary artery bypass surgery with emphasis on working memory performance

Previous researches have provided contradictory results about on working memory performance after the coronary artery bypass graft (CABG). In addition, studies have focused on the elderly community. For this reason and with regard to the importance and direct effects of working memory on the quality of life human. This study was designed to compare working memory of young CABG patients with age range of 30-55 years one year postoperatively with healthy subjects.

In this Case-control study, which was conducted from February 2017 to October 2018, two groups of people, 40 patient men with coronary artery bypass graft that admitted to the heart center of Tehran in last year and 64 healthy males were selected with using available sampling method. Both groups were tested with Wechsler's working memory scale.

The results of the study showed that the mean and standard deviation of the age of coronary artery bypass graft patients were 52.65 and 5.559, respectively, and the mean and standard deviation of healthy subjects were 41.81 and 8.619, respectively. The results showed that The two group had significantly difference (P<0.01), in the sub scales of the working memory including of the forward auditory memory and reverse auditory memory, total score of auditory memory, reverse visual memory and auditory memory span and the two groups had significantly difference (P<0.05), in the total score of visual memory. But the two group had not significantly difference (P>0.05) in the forward visual memory (CABG [mean=5.40 & standard deviation=1.41] Healty people [mean=6.13 & standard deviation=3]) and visual memory span (CABG [mean=5.35 & standard deviation=1.12] Healty people [mean=5.56 & standard deviation=1.97]). The results showed that Patients with CABG than healthy people have overall poorer results for all sub scales the of working memory test.

The results of this study confirm the prevalence of relatively high cognitive decline, especially in working memory after CABG, and provide a pattern of persistence of cognitive decline after one year of coronary artery bypass surgery in young patients aged 30 to 55 years.