Pulmonary hypertension (PH) is often caused by left heart disease (group 2 PH) , which is difficult to diagnose early and with a high mortality rate. Potassium channel dysfunction is a marker of PH, however, the epidemiological data of the disease and the effect of potassium ions on PH still remain unclear.

To investigate the correlation of serum potassium level with myocardial markers, echocardiographic indicators and length of hospital stay in patients with group 2 PH, and evaluate the predictive value of serum potassium levels for the severity of group 2 PH, so as to provide the oretical basis for clinical diagnosis and treatment.

The clinical data of 400 adult inpatients diagnosed with group 2 PH in the First Hospital of Shanxi Medical University from January 2020 to December 2021 were retrospectively collected as follows: (1) general data: gender, age, BMI, length of hospital stay, smoking status, smoking index (SI) and drinking history; (2) underlying diseases (diabetes mellitus, hypertension) ; (3) laboratory data: serum potassium level, myocardial markers[procalcitonin, N-terminal pro-brain natriuretic peptide (NT-proBNP) , cardiac troponin I, cardiac troponin T, creatine kinase-MB], echocardiographic indicators (left atrial diameter, right ventricular diameter, right atrial area, left ventricular ejection fraction, shortening fraction, peak tricuspid regurgitation velocity, pulmonary artery systolic pressure) . The patients were divided into <3.5 mmol/L group (n=57) , 3.5-5.5 mmol/L group (n=340) and >5.5 mmol/L group (n=3) according to the serum potassium level. Spearman correlation analysis was used to explore the correlation of serum potassium level with myocardial markers and echocardiographic indicators. Log-rank (Mantel-Cox) test was used to compare the discharge rate of patients with different serum potassium levels. Receiver operating characteristic curve (ROC curve) was plotted to evaluate the predictive value of serum potassium level for the severity of group 2 PH.

Procalcitonin and NT-proBNP levels of patients in the >5.5 mmol/L group were significantly higher than the <3.5 mmol/L group (P<0.05) . Correlation analysis showed that serum potassium level was positively correlated with NT-proBNP (r_s=0.133) , peak tricuspid regurgitation velocity (r_s=0.017) and pulmonary artery systolic pressure (PASP) (r_s=0.126) (P<0.05) . Serum potassium level was further classified as <3.5 mmol/L, 3.5-3.9 mmol/L, 4.0-4.9 mmol/L, 5.0-5.5 mmol/L, and >5.5 mmol/L to investigate its relationship with length of hospital stay in depth. Log-rank (Mantel-Cox) testresults showed that for group 2 PH patients greater than average hospitalization levels, there was a significant difference in cumulative hospitalization rates among patients with different serum potassium levels (<3.5 mmol/L, 3.5-3.9 mmol/L, 4.0-4.9 mmol/L, 5.0-5.5 mmol/L, >5.5 mmol/L) (P=0.022) . ROC analysis showed that the diagnostic value of serum potassium level for non-mild PH (AUC=0.577, cut-off value=3.91 mmol/L, sensitivity=64.7%, specificity=52.5%) was similar to that of NT-proBNP (AUC=0.585, cut-off value=1 070.69 pg/mL, sensitivity=78.1%, specificity=39.6%) , which can effectively predict the severity of group 2 PH.

Serum potassium level can predict the severity of group 2 PH and the length of hospital stay. Intervention of serum potassium levels may be one of the new approach to prevent and treat PH.

肺动脉高压（PH）常由左心疾病所致（2类PH），早期诊断困难，病死率高，钾通道功能障碍是PH的标志，但该病的流行病学数据仍不清楚，钾离子对PH的影响尚不明确。

探讨2类PH患者的血钾水平与心肌标志物、超声心动图指标及住院时间的关系，评价血钾水平对2类PH严重程度的预测价值，为临床诊断治疗提供理论依据。

回顾性收集2020年1月—2021年12月在山西医科大学第一医院诊断为2类PH的400例成年住院患者的病例资料。（1）一般资料：性别、年龄、BMI、住院时间、吸烟情况及吸烟指数（SI）、饮酒史。（2）基础病（糖尿病、高血压）。（3）实验室资料：血钾、心肌标志物[降钙素原、N末端B型钠尿肽前体（NT-proBNP）、肌钙蛋白I、肌钙蛋白T、肌酸激酶同工酶]、超声心动图指标（左心房前后径、右心室前后径、右心房面积、左心室射血分数、缩短分数、右房室瓣反流峰值流速、肺动脉收缩压）。依据血钾水平将纳入患者分为3组：<3.5 mmol/L组（n=57）、3.5~5.5 mmol/L组（n=340）、>5.5 mmol/L组（n=3）。采用Spearman秩相关分析探讨血钾水平与心肌标志物、超声心动图指标的相关性；采用Log-rank（Mantel-Cox）检验比较不同血钾水平患者的出院率；通过绘制受试者工作特征曲线（ROC曲线）评价血钾对2类PH严重程度的预测价值。

>5.5 mmol/L组患者降钙素原及NT-proBNP高于<3.5 mmol/L组（P<0.05）。相关性分析结果表明，血钾水平与NT-proBNP（r_s=0.133）、右房室瓣反流峰值流速（r_s=0.017）、肺动脉收缩压（r_s=0.126）呈正相关（P<0.05）。将血钾水平进一步分为<3.5 mmol/L、3.5~3.9 mmol/L、4.0~4.9 mmol/L、5.0~5.5 mmol/L、>5.5 mmol/L，以深入研究血钾水平与患者住院时间的关系。Log-rank（Mantel-Cox）检验结果显示，对于大于平均住院水平的2类PH患者，不同血钾水平患者（<3.5 mmol/L、3.5~3.9 mmol/L、4.0~4.9 mmol/L、5.0~5.5 mmol/L、>5.5 mmol/L）的累积住院率比较，差异有统计学意义（P=0.022）。ROC曲线结果显示，血钾对非轻症PH的诊断价值[ROC曲线下面积（AUC）= 0.577，截断值为3.91 mmol/L，灵敏度为64.7%，特异度为52.5%]与NT-proBNP的诊断价值相近（AUC=0.585，截断值为1 070.69 pg/mL，灵敏度为78.1%，特异度为39.6%），可有效预测2类PH的严重程度。

血钾水平可预测2类PH患者的严重程度及住院时间，干预血钾水平可能是防治PH的新途径之一。