Abstract: Background Pulmonary hypertension（PH）associated with left heart disease（PH-LHD）is the most common form of PH. Studies have shown that serum sodium is associated with the severity and poor prognosis of group 1 PH， but the effect of serum sodium on PH-LHD has rarely been reported. Objective To investigate the relationship between serum sodium and N-terminal pro-brain natriuretic peptide（NT-proBNP）and echocardiographic indexes in PH-LHD patients，and evaluate the effect of serum sodium on the severity and length of stay of PH-LHD，so as to provide theoretical basis for clinical diagnosis and treatment of PH-LHD patients and improvement of hospital turnover. Methods The clinical data of 360 adult inpatients diagnosed with PH-LHD in the First Hospital of Shanxi Medical University from January 2020 to February 2022 were collected. According to the median serum sodium of 139 mmol/L（serum sodium <135 mmol/L is hyposodium），the patients were divided into 3 groups：<135 mmol/L group（n=50），135-139 mmol/L（n=136）and 140-145 mmol/L（n=174）. Spearman correlation analysis was used to explore the correlation of serum sodium level with length of hospital stay，NT-proBNP and echocardiographic indicators. Kaplan-Meier was used to compare the length of hospital stay of PH-LHD patients with different serum sodium levels. Binary Logistic regression analysis was used to investigate the effect of serum sodium levels on the length of hospital stay in PH-LHD patients. Results Age，length of stay，NT-proBNP，left atrial diameter ，right atrium area ，left ventricular ejection fraction and shortening fraction of PH-LHD patients in 3 groups were compared，and the differences were statistically significant（P<0.05）. The length of hospitalization and NT-proBNP of patients in the serum sodium 140-145 mmol/ L group were lower than those in the serum sodium <135 mmol/L group and the serum sodium 135-139 mmol/L group（P<0.05）. Spearman correlation analysis showed that serum sodium level was negatively correlated with length of stay（r=-0.176），NTproBNP（r=-0.135），right ventricular diameter（r=-0.110）and pulmonary artery systolic pressure（r=-0.105）in PH-LHD patients（P<0.05）. The Kaplan-Meier survival showed that there were statistically significant differences between the length of hospital stay among the three groups of PH-LHD patients with different serum sodium levels. Binary Logistic regression analysis showed that increased serum sodium level was a protective factor for longer hospital stay in PH-LHD patients after correcting each control variable（OR=0.916，95%CI=0.859-0.977，P=0.008）. The risk of prolonged hospitalization was elevated in patients with serum sodium <135 mmol/L and those with serum sodium 135-139 mmol/L compared with patients with serum sodium 140- 145 mmol/L. Conclusion Serum sodium level is closely related to the severity of PH-LHD，and decreased serum sodium level is an independent risk factor for the length of hospital stay in PH-LHD patients. It is a potential therapeutic consideration，providing new strategies for the diagnosis and treatment of PH-LHD and hospital turnover.

Key words: Pulmonary arterial hypertension, Pulmonary hypertension associated with left heart disease, Serum sodium, Echocardiography, Length of stay, Logistic models

摘要： 背景　左心疾病相关肺动脉高压（PH-LHD）是肺动脉高压（PH）中最常见的一种。研究表明，血钠水平与 1 类 PH 的严重程度和不良预后相关，然而，其对 PH-LHD 的影响鲜有报道。目的　探讨 PH-LHD 患者的血钠水平与 N 末端脑利钠肽前体（NT-proBNP）、超声心动图指标的关系，评价血钠水平对 PH-LHD 严重程度及住院时间的影响，为 PH-LHD 患者的临床诊疗及提高医院周转率提供理论依据。方法　收集 2020 年 1 月—2022 年 2 月在山西医科大学第一医院住院的 360 例 PH-LHD 患者的临床资料，依据患者的中位血钠水平 139 mmol/L（血钠 <135 mmol/L为低血钠），将患者分为 3 组：血钠 <135 mmol/L 组（50 例）、血钠 135~139 mmol/L（136 例）、血钠 140~145 mmol/L（174 例）。采用 Spearman 秩相关分析探讨血钠水平与住院时间、NT-proBNP 及超声心动图指标的相关性；采用 Kaplan-Meier 生存曲线分析比较不同血钠水平 PH-LHD 患者的住院时间；采用二元 Logistic 回归分析探讨血钠水平对 PH-LHD 患者住院时间的影响。结果　3 组 PH-LHD 患者年龄、住院时间、NT-proBNP、左心房前后径、右心房面积、左心室射血分数、缩短分数比较，差异有统计学意义（P<0.05）；其中血钠 140~145 mmol/L 组患者的住院时间、NT-proBNP 低于血钠 <135 mmol/L 组及血钠 135~139 mmol/L 组（P<0.05）。Spearman 秩相关分析结果显示，PH-LHD 患者血钠水平与住院时间（r=-0.176）、NT-proBNP（r=-0.135）、右心室前后径（r=-0.110）、肺动脉收缩压（r=-0.105）均呈负相关（P<0.05）。Kaplan-Meier 生存曲线分析结果显示，3 组血钠水平的 PH-LHD 患者住院时间比较，差异有统计学意义（χ2=12.469，P=0.002）。二元 Logistic 回归分析校正各控制变量后结果显示，血钠水平升高是 PH-LHD 患者住院时间延长的保护因素（OR=0.916，95%CI=0.859~0.977，P=0.008）；与血钠 140~145 mmol/L 患者相比，血钠 <135 mmol/L（OR=2.268，95%CI=1.049~4.903，P=0.037）及血钠 135~139 mmol/L（OR=2.056，95%CI=1.163~3.635，P=0.013）患者住院时间延长的风险均升高。结论　血钠水平与 PH-LHD 严重程度密切相关，血钠水平降低是 PH-LHD 患者住院时间的独立危险因素，是一种潜在的治疗考虑因素，为 PH-LHD 的诊疗及医院周转提供新策略。

关键词: 肺动脉高压, 左心疾病相关肺动脉高压, 血钠, 超声心动图, 住院时间, Logistic 模型