Relationship between admission serum chloride level and postoperative short-term mortality in patients with Acute Stanford type A aortic dissection postprint

Abstract: Background: Acute Stanford type A aortic dissection (AAAD) is a fatal disease that can have a catastrophic impact on a patient's life, but preoperative risk factors affecting a patient's prognosis are still limited. Serum chlorine (Cl-) is an important anion of the human body, which affects the occurrence and development of many diseases, but the relationship between Serum chlorine and AAAD is not clear. Objective: To investigate the relationship between admission serum chloride level and postoperative 30-day all-casue mortality in patients with acute Stanford type A aortic dissection (AAAD). Methods: A retrospective cohort design was used. 206 AAAD patients who underwent Sun's procedure from February 2016 to December 2019 in the Fourth Hospital of Hebei Medical University were enrolled. Patients were classified into three groups (T1-T3) according to the admission serum chloride fertile:T1≤102 mmol/L(n=69), 102＜T2≤106 mmol/L(n=70), T3>106 mmol/L(n=67). The primary endpoint was 30-day all-cause mortality, while the secondary endpoints included 30-day all-cause mortality and major adverse events. Univariate and multivariate logistic regression analysis was performed to evaluate the association between serum chloride and 30-day all-cause mortality. Kaplan-Meier curves were used to analyze the 30 day cumulative survival rate of the different groups. Results: The postoperative 30-day mortality and incidence of adverse events in patients with AAAD were 16.1% and 22.8%, respectively. The short-term prognosis of patients with different serum chlorine groups is different. AUC was 0.695 [95%CI （0.595，0.796），P<0.001], sensitivity and specificity were 54.5% and 78.6%, respectively. The optimal cut off value for serum chloride as a predictor of 30-day death was 107 mmol/L in the ROC curve analysis. Serum chloride [OR=1.168，95%CI （1.058，1.289），P＜0.002] at admission was an independent risk factor postoperative in-hospital death in patients with AAAD by multivariate logistic regression analysis. Moreover, the postoperative in-hospital mortality in T3 group was 3.785 times higher than that in T1 group [95CI （1.121，12.782），P=0.032], the postoperative in-hospital mortality in ＞107 mmol/L group was 3.367 times higher than that in ≤107mmol/L group[95CI（1.469，9.186），P=0.005]. Kaplan-Meier curves showed patients with higher serum chlorine levels had a poor cumulative survival rate at 30-day after operation. Additionally, serum chlorine and sodium were moderately correlated (r=0.401, P<0.001). The subgroup analysis showed that there was a certain interaction between serum chloride and serum sodium ( P for interaction = 0.012), and the adverse effect of blood chloride on the short-term prognosis of patients was more significant in patients with low serum sodium, suggesting that serum chlorine is better in prognostic value than that of serum sodium. Conclusion Admission serum chloride may be related to the postoperative death of AAAD patients.