目的:探讨有创心肺运动试验(iCPET)在不明原因呼吸困难患者中的临床诊断应用。
方法:进行回顾性分析,涵盖2017年5月5日至2020年10月1日期间主诉劳力性呼吸困难的患者。对常规检查未明确病因的患者进行右心导管检查,如果通过右心导管检查没有明确病因,则对患者进行iCPET.根据结果和iCPET的诊断标准,右心导管检查无明显异常的患者分为四个亚组:运动诱发肺动脉高压(eiPAH),射血分数保留的运动性心力衰竭(EIHFpEF),预加载失效,和氧化肌病.通过比较实验室测试,超声心动图,亚组的右心导管和iCPET峰值运动数据,描述了iCPET检查的无法解释的呼吸困难患者的疾病分布和运动血流动力学特征。
结果:在1046例劳力性呼吸困难患者中,771例诊断为常规检查,而在剩下的275名患者中,131例(47.6%)诊断为右心导管检查,144例(52.4%)在常规检查和右心导管检查后无明确病因。在这144名患者中,49例(34.0%)接受iCPET,中位运动时间为375s。共有47例患者完成了检查,男女比例为0.27∶1,平均年龄为(47.9±14.4)岁。在47名患者中,年龄在20至59岁之间的76.6%(36/47)和78.7%(36/47)居住在城市地区。预负荷失败组(n=27)在峰值运动强度下显示出右心房压力较低。eiHFpEF组(n=9)在运动强度达到峰值时显示出肺毛细血管的高楔压。eiPAH组(n=8)在峰值运动强度下显示出较高的平均肺动脉压。氧化性肌病组(n=3)的特征是运动过程中组织摄取和/或利用氧的损害。根据预紧力破坏的三个子组之间的比较,eiHFpEF和eiPAH,在常规检查中,eiPAH组血K+水平最高,而预负荷失败组血K+水平最低(P=0.014)。三个亚组的iCPET在运动期间右心房压力升高方面具有统计学意义(P=0.001)。在这三个人中,eiHFpEF组的增幅最高,预紧失效组的增幅最低.结论对右心导管检查无异常结果的不明原因呼吸困难患者,主要原因是预加载失败,表现为运动强度峰值时右心房压力低。研究表明,当右心导管插入未发现病因时,iCPET对呼吸困难病例具有重要价值。
OBJECTIVE: To explore the clinical diagnostic application of invasive cardiopulmonary exercise test (iCPET) in patients with unexplained dyspnea.
METHODS: A retrospective analysis was conducted, covering patients with a chief complaint of exertional dyspnea between May 5, 2017 and October 1, 2020. Right cardiac catheterization examination was performed on patients whose cause had not been identified through routine examination, and further iCPET was performed on patients if no clear etiology was identified through right cardiac catheterization. According to the results and the diagnostic criteria of iCPET, patients showing no obvious abnormalities in the right cardiac catheterization examination were divided into four subgroups: exercise-induced pulmonary arterial hypertension (eiPAH), exercise-induced heart failure with preserved ejection fraction (eiHFpEF), preload failure, and oxidative myopathy. By comparing the lab test, echocardiography, right heart catheter and iCPET peak exercise data of the subgroups, the disease distribution and exercise hemodynamic characteristics of patients with unexplained dyspnea examined by iCPET were described.
RESULTS: Of the 1 046 patients with exertional dyspnea, 771 were diagnosed with routine examination, while among the remaining 275 patients, 131 (47.6%) were diagnosed with right cardiac catheterization and 144 (52.4%) showed no clear etiology after routine examination and right cardiac catheterization. Of these 144 patients, 49 (34.0%) received iCPET with a median exercise time of 375 s. A total of 47 patients completed the examination, with a male-to-female ratio of 0.27∶1 and an average age of (47.9±14.4) years old. Among the 47 patients, 76.6% (36/47) aged between 20 and 59 and 78.7% (36/47) lived in urban areas. The preload failure group ( n=27) showed low right atrium pressure at peak exercise intensity. The eiHFpEF group ( n=9) showed high wedge pressure of pulmonary capillaries at peak of exercise intensity. The eiPAH group ( n=8) showed high average pulmonary artery pressure at peak exercise intensity. The oxidative myopathy group ( n=3) was characterized by impairment of tissue uptake and/or utilization of oxygen during exercise. According to the comparison among the three subgroups of the preload failure, eiHFpEF and eiPAH, the eiPAH group had the highest blood K + level in routine examination, while the preload failure group had the lowest blood K + level ( P=0.014). The iCPET of the three subgroups showed statistically significant ( P=0.001) difference in right atrial pressure increase during exercise. Among the three, the eiHFpEF group had the highest increase and the preload failure group had the lowest increase. Conclusion In unexplained dyspnea patients showing no abnormal results in right cardiac catheterization examination, the main cause was preload failure, which manifested as low right atrial pressure at peak exercise intensity. The study showed that iCPET was of important value for dyspnea cases when the cause of the condition was not revealed with right cardiac catheterization.