Title: Preoperative predictors of postoperative cognitive dysfunction after Y-graft replacement for abdominal aortic aneurysm

Background and Goal of Study: Postoperative cognitive dysfunction (POCD) is believed to occur from operative stress. It causes longer hospital stay, poorer quality of life, and higher mortality rate. Y-graft replacement is a highly invasive procedure and rate of POCD after Y-graft replacement is expected to be high, but only a few reports have been made on the preoperative predictors of POCD after Y-graft replacement. The object of this study was to identify the preoperative predictors of POCD after Y-graft replacement.
Materials and Methods: We retrospectively reviewed medical records of patients who underwent Y-graft replacement for Abdominal aortic aneurysm (n=65) between July 2010 and September 2013 at the Kumamoto Chuo Hospital. Surgeries were performed under either general anesthesia or combined general and epidural anesthesia. POCD was measured by 4 neuropsychological tests [the Hasegawa dementia scale (HDS: modification of the Mini-Mental State Examination), the Kana pick-up test, the Disit symbol test, the Disit span test]. The tests were done preoperatively (baseline) and one week post-operatively. POCD was defined as a decrease of at least 20% of baseline in performance post operatively in at least 1 test. Comparisons between POCD group and non-POCD group were made with Student’s t test and the χ2 or Fisher’s exact test. To assess the predictors and probability of POCD, stepwise logistic regression analysis was performed.
Results and Discussion: POCD was identified in 24 of the 65 patients (37.0%). POCD group had significantly higher age (75.2 ± 6.71 vs 70.6 ± 6.72), lower score in neuropsychological tests: HDS (25.3 ± 3.2 vs 28.4 ± 1.9), the Kana pick-up test (20.2 ± 10.4 vs 28.2 ± 12.7), the Disit symbol test (30.5 ± 11.6 vs 41.1 ± 11.3) (p<0.05, respectively). Stepwise logistic regression analysis demonstrated that the significant predictors of POCD were history of cerebrovascular disease (CVD) [odds ratio (OR) 3.04], age 74 years old and above (OR 4.47), and a score of getting 28 marks or less in HDS (OR 7.76). The probability of POCD with 3 risk factors was 0.969. The lower score in HDS may be a reflection of decreasing cognitive reserve due to CVD and aging, although. MRI examination was not performed pre-operatively. HDS may be useful to evaluate POCD before surgery in elderly patient with history of CVD.
Conclusion: The incidence of POCD after Y-graft replacement was 37.0% (24 /65). Cerebrovascular disease, age, HDS are the preoperative predictors of POCD.

Preoperative predictors of postoperative cognitive dysfunction after y-graft replacement for abdominal aortic aneurysm