A simpler noninvasive method of predicting markedly elevated pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension

Ya-Nan Zhai; Ai-Li Li; Xin-Cao Tao; Wan-Mu Xie; Qian Gao; Yu Zhang; Ai-Hong Chen; Jie-Ping Lei; Zhen-Guo Zhai

doi:10.1002/pul2.12102

A simpler noninvasive method of predicting markedly elevated pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension

Pulm Circ. 2022 Jul 1;12(3):e12102. doi: 10.1002/pul2.12102. eCollection 2022 Jul.

Authors

Ya-Nan Zhai^{1

2

3}, Ai-Li Li^{1

2

3}, Xin-Cao Tao^{2

3

4}, Wan-Mu Xie^{2

3

4}, Qian Gao^{2

3

4}, Yu Zhang¹, Ai-Hong Chen¹, Jie-Ping Lei^{2

3

5}, Zhen-Guo Zhai^{2

3

4}

Affiliations

¹ Department of Cardiology China-Japan Friendship Hospital Beijing China.
² Institute of Respiratory Medicine Chinese Academy of Medical Sciences Beijing China.
³ National Clinical Research Center for Respiratory Diseases Beijing China.
⁴ Department of Pulmonary and Critical Care Medicine China-Japan Friendship Hospital Beijing China.
⁵ Data and Project Management Unit, China-Japan Friendship Hospital Institute of Clinical Medical Sciences Beijing China.

Abstract

Several echocardiographic methods to estimate pulmonary vascular resistance (PVR) have been proposed. So far, most studies have focused on relatively low PVR in patients with a nonspecific type of pulmonary hypertension. We aimed to clarify the clinical usefulness of a new echocardiographic index for evaluating markedly elevated PVR in chronic thromboembolic pulmonary hypertension (CTEPH). We studied 127 CTEPH patients. We estimated the systolic and mean pulmonary artery pressure using echocardiography (sPAP_Echo, mPAP_Echo) and measured the left ventricular internal diameter at end diastole (LVIDd). sPAP_Echo/LVIDd and mPAP_Echo/LVIDd were then correlated with invasive PVR. Using receiver operating characteristic curve analysis, a cutoff value for the index was generated to identify patients with PVR > 1000 dyn·s·cm^-5. We analyzed pre- and postoperative hemodynamics and echocardiographic data in 49 patients who underwent pulmonary endarterectomy (PEA). In this study, mPAP_Echo/LVIDd moderately correlated with PVR (r = 0.51, p < 0.0001). There was a better correlation between PVR and sPAP_Echo/LVIDd (r = 0.61, p < 0.0001). sPAP_Echo/LVIDd ≥ 1.94 had an 77.1% sensitivity and 75.4% specificity to determine PVR > 1000 dyn·s·cm^-5 (area under curve = 0.804, p < 0.0001, 95% confidence interval [CI], 0.66-0.90). DeLong's method showed there was a statistically significant difference between sPAP_Echo/LVIDd with tricuspid regurgitation velocity²/velocity-time integral of the right ventricular outflow tract (difference between areas 0.14, 95% CI, 0.00-0.27). The sPAP_Echo/LVIDd and mPAP_Echo/LVIDd significantly decreased after PEA (both p < 0.0001). The sPAP_Echo/LVIDd and mPAP_Echo/LVIDd reduction rate (ΔsPAP_Echo/LVIDd and ΔmPAP_Echo/LVIDd) was significantly correlated with PVR reduction rate (ΔPVR), respectively (r = 0.58, p < 0.01; r = 0.69, p < 0.05). In conclusion, the index of sPAP_Echo/LVIDd could be a simpler and reliable method in estimating CTEPH with markedly elevated PVR and also be a convenient method of estimating PVR both before and after PEA.

Keywords: chronic thromboembolic pulmonary hypertension; echocardiography; pulmonary endarterectom; pulmonary vascular resistance.