AKI is one of the most common complications after cardiac extracorporeal circulation procedures resulting in prolonged hospitalization and increased mortality. The occurrence of AKI after cardiac surgery is 40.6%-52.7%3 13 14.In this study, the incidence of AKI after ATAAD operation as 64.7%,but the number of patients who needed RRT treatment was 19 (18.6%), consistent with Tian yu Zhou's study15.However, AKI prevalence was 64.7% in our study, which is relatively high because we included patients of all stages based on the KIDGO criteria, including those with renal failure and requiring RRT.
Platelets have a pro-inflammatory effect and can release self-stored pro-inflammatory factors after platelet activation. In recent years, so much studies have confirmed that platelets participate in inflammatory reactions, which can release IL-6 and IL-1 after platelet activation, who can induce expressing monocytes, promote their adhesion to endothelial cells, and synthesize TNF-and IL-6. This suggests that platelet activation is involved in the systemic inflammatory response process of aortic dissection16 17.So much studies have explored the pathophysiological of cardiac surgery-associated acute kidney injury, which include inflammation 18, oxidative stress, ischemia-reperfusion injury, surgical trauma, blood exposed to the artificial surface of CPB circuit,and is multifactorial.19 20.The platelet counts reduces is observed after CPB21. Study shows decreased platelet counts increases the risk of AKI22 23.In our study, we found that the postoperative early PLR were significantly low in patients who with AKI. Multivariate logistic regression analysis showed that the postoperative reduced PLR within 24h is a risk factor for the occurrence of AKI in ATAAD patients, which could be used as a predictor of AKI in ATAAD patients after surgery. The ROC curve analysis suggested that T1 PLR can predict the incidence of AKI in ATAAD patients after surgery. Chen-Fei Zheng observed that both low and high PLR were increased the 30-day and 90-day mortality 24.As different design of the study protocol, We did not classify PLR into low and high PLRs, and did not studied their correlation with the occurrence of postoperative AKI. We found that the AKI group T1 PLR was lower than that in the NON-AKI group, and T1 PLR had some predictive value for the occurrence of AKI. There is no differences on T0 PLR between the two groups. Hakan Parlar1 found that a greater inflammatory response is triggered in patients who will develop AKI in later days after surgery22.Maybe the inflammation reaction had not reached its peak, inflammation indicators had no predictive value at preoperative. Moreover, the different surgical method selection and postoperative monitoring measures, and the results may be biased.
Based on multivariate logistic regression analysis, Higher BMI and decreased T1 PLR all contributed to AKI development. Higher BMI was associated with AKI, In fact, several studies have shown that obesity is associated with a high incidence and severity of AKI25 26.In the multivariate analysis, several variables associated with AKI in the univariate analysis were not significant. The gender, hypertension, T0 PLR ,hypoalbumin were not independent risk factors, in the same time, we found the duration of CPB and AOT not an independent risk factor for AKI, which is in contrast to other studies6 11 12 27 28. The bias of research results may be due to differences in cardiopulmonary bypass and surgical techniques, In our study, the duration of cardiopulmonary bypass time was 282.50 (91.00) min, and the aortic occlusion time was 167.17 ± 49.10 min, which were longer than other study29 30.
Limitations
However, there were some limitations to our study. First, due to the difference in individual medical treatment, we could not acquire the real baseline sCr values of the patients; instead, we used admission sCr as the baseline value, which might have underestimated the incidence of AKI. Second, this is a single-center retrospective study with small sample size. Consequently, a larger sample size and prospective randomized trials are required to confirm the association between the prevalence of AKI and PLR levels.