Effects of right ventricular remodeling in chronic thromboembolic pulmonary hypertension on the outcomes of balloon pulmonary angioplasty: a 2D-speckle tracking echocardiography study.

BACKGROUND: Balloon pulmonary angioplasty (BPA) improves the prognosis of chronic thromboembolic pulmonary hypertension (CTEPH). Right ventricle (RV) is an important predictor of prognosis in CTEPH patients. 2D-speckle tracking echocardiography (2D-STE) can evaluate RV function. This study aimed to evaluate the effectiveness of BPA in CTEPH patients and to assess the value of 2D-STE in predicting outcomes of BPA. METHODS: A total of 76 patients with CTEPH underwent 354 BPA sessions from January 2017 to October 2022. Responders were defined as those with mean pulmonary artery pressure (mPAP) ≤ 30 mmHg or those showing ≥ 30% decrease in pulmonary vascular resistance (PVR) after the last BPA session, compared to baseline. Logistic regression analysis was performed to identify predictors of BPA efficacy. RESULTS: BPA resulted in a significant decrease in mPAP (from 50.8 ± 10.4 mmHg to 35.5 ± 11.9 mmHg, p < 0.001), PVR (from 888.7 ± 363.5 dyn·s·cm-5 to 545.5 ± 383.8 dyn·s·cm-5, p < 0.001), and eccentricity index (from 1.3 to 1.1, p < 0.001), and a significant increase in RV free wall longitudinal strain (RVFWLS: from 15.7% to 21.0%, p < 0.001). Significant improvement was also observed in the 6-min walking distance (from 385.5 m to 454.5 m, p < 0.001). After adjusting for confounders, multivariate analysis showed that RVFWLS was the only independent predictor of BPA efficacy. The optimal RVFWLS cutoff value for predicting BPA responders was 12%. CONCLUSIONS: BPA was found to reduce pulmonary artery pressure, reverse RV remodeling, and improve exercise capacity. RVFWLS obtained by 2D-STE was an independent predictor of BPA outcomes. Our study may provide a meaningful reference for interventional therapy of CTEPH.

Efficacy of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension patients with pulmonary comorbidity.

Background: Balloon pulmonary angioplasty (BPA) is an established treatment for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its efficacy in CTEPH patients with a pulmonary comorbidity has not been well-studied. Here, we compared post-BPA outcomes between CTEPH patients with and without chronic pulmonary disease at baseline and analyzed predictors of BPA success. Methods: From August 2017 to October 2022, 62 patients with inoperable CTEPH who underwent BPA were consecutively enrolled and grouped based on the presence of a pulmonary comorbidity at baseline. All patients underwent transthoracic echocardiography, pulmonary function tests, and right heart catheterization. Pre- and post-BPA data were evaluated to identify factors that influence the success of BPA. Results: Among the 62 CTEPH patients, BPA was considered successful in 50 patients and unsuccessful in 12 patients. Responders to BPA had better exercise capacity and right heart function at baseline, but no differences in hemodynamic or respiratory function were detected between the groups. In CTEPH patients with chronic pulmonary disease (n = 14), BPA significantly improved mean pulmonary arterial pressure, pulmonary vascular resistance and right heart function parameters. Only CTEPH patients without chronic pulmonary disease (n = 48) exhibited significant improvement in 6-minute walk distance and respiratory function. Multivariate logistic regression analysis showed that pulmonary comorbidity at baseline was independently associated with the efficacy of BPA. Conclusions: BPA provided significantly improvements in hemodynamics and right heart function in CTEPH patients, independent of pulmonary comorbidity at baseline. However, pulmonary comorbidity can negatively impact post-BPA outcomes.

Padua prediction score may be inappropriate for VTE risk assessment in hospitalized patients with acute respiratory conditions: A Chinese single-center cohort study.

Background: The Padua Prediction Score (PPS) recommended by the guidelines lacks effective external validation in a Chinese cohort. This study sought to assess the accuracy of the PPS to predict venous thromboembolism (VTE) risk in medical inpatients with acute respiratory conditions. Methods: This consecutive cohort study included 1,574 inpatients from January to August 2019. The occurrence rate of VTE in patients classified at high-risk and low-risk groups according to PPS and Caprini risk assessment model (RAM) was compared. The discriminatory capability of the RAMs was evaluated in all the patients and the subgroup without pharmacological prophylaxis. Reclassification parameters were also used to assess the clinical utility. Results: 170 (10.8%) patients were objectively confirmed as having VTE during hospitalization. The incidence rate of VTE in low-risk patients was 6.3% by PPS, which was significantly higher than that by Caprini RAM (2.6%, p < 0.001). The area under the curve (AUC) for PPS and Caprini RAM was 0.714 (95%CI, 0.672-0.756) and 0.760 (95%CI, 0.724-0.797), respectively (p = 0.003). The AUC of Caprini RAM was larger than PPS even in subgroups without pharmacological prophylaxis (0.774 vs 0.709, p = 0.002). Compared with Caprini RAM, the net reclassification index was estimated at 0.037 (p = 0.436), and integrated discrimination improvement was 0.015 (p = 0.495) by PPS. Conclusions: According to our cohort study, PPS may not be appropriate to predict VTE risk in hospitalized patients with acute respiratory conditions. An accurate, widely applicable, validated RAM needs to be further constructed in Chinese medical inpatients.

The Role of Strain by Cardiac Magnetic Resonance Imaging in Predicting the Prognosis of Patients with Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombotic obstruction of the pulmonary arteries, and right ventricular (RV) dysfunction is a major cause of death. Cardiac magnetic resonance (CMR) is the gold standard for assessing heart wall deformation; therefore, we aimed to determine the prognostic value of CMR strain in patients with CTEPH. Strain derived by CMR was measured at the time of diagnosis in 45 patients with CTEPH, and the relationship between RV strain and prognosis was determined through follow-up. The value of RV strain in the prognostic model was compared with that of pulmonary arterial hypertension (PAH) risk stratification. The RV global peak longitudinal strain (GLS) and global peak circumferential strain (GCS) in CTEPH patients were lower than the normal references of RV strain in the control group. GLS and longitudinal strain in the basal segment were independent risk factors for adverse events (P < .050). Adding CMR parameters to PAH risk stratification improved its predictive power in patients with CTEPH. GLS and GCS scores were impaired in patients with chronic RV overload. RV strain derived by CMR imaging is a promising noninvasive tool for the follow-up of patients with CTEPH.

Echocardiographic Characteristics of Pulmonary Artery Intimal Sarcoma: Comparison With CTPA.

OBJECTIVES: This study examined the echocardiographic characteristics of patients with pulmonary artery intimal sarcoma (PAIS) and compared the results with those from computed tomographic pulmonary angiography (CTPA). METHOD: Twenty-six (26) patients were diagnosed with PAIS at the current institution during the study period, and 23 were eligible for analysis. Echocardiography and CTPA examinations were performed in all enrolled patients. RESULTS: The echocardiography results showed that most lesions had expansive growth in the left pulmonary artery (PA); the right PA; or a combination of the left PA, right PA, and main PA, with extension to the pulmonary valve and/or right ventricular outflow tract. These lesions also had distinctive sieve-like echogenic signals. Echocardiography also showed that some lesions had lobulated shapes, were nearly round and echolucent or with calcifications, and moved during imaging. The lesion distribution was similar in CTPA and echocardiography (p=0.361), but CTPA was more sensitive in detection of the complete shape (p=0.023). CONCLUSIONS: The unique echocardiographic characteristics of PAIS, especially the "sieve sign", could help in the diagnosis of this cancer. Transthoracic echocardiography is a non-invasive technique that appears effective in detecting PAIS.

Analysis of clinical features between active and inactive patients of Takayasu's arteritis with pulmonary arteries involvement.

BACKGROUND: The aim of this study was to investigate the clinical characteristics of patients between active and inactive Takayasu's arteritis with pulmonary artery involvement (PTA) and to identify better markers of disease activity in these patients. METHODS: Sixty-four PTA patients in Beijing Chao-yang hospital (2011 to 2021) were included. According to National Institutes of Health criteria, 29 patients were in active stage and 35 were in inactive stage. Their medical records were collected and analyzed. RESULTS: Compared with inactive group, patients in active group were younger. More patients in active stage presented fever (41.38% vs 5.71%), chest pain (55.17% vs 20%), increased C-reactive protein (2.91 vs 0.46 mg/L), erythrocyte sedimentation rate (35.0 vs 9 mm/h), and platelet count (291 vs 221 × 109/L). Pulmonary artery wall thickening was more common in active group (51.72% vs 11.43%). These parameters were restored after treatment. The incidence of pulmonary hypertension was comparable between groups (34.48% vs 51.43%), but patients in active group had lower pulmonary vascular resistance (PVR) (361.0 vs 891.0 dyn·s·cm-5) and higher cardiac index (2.76 ± 0.72 vs 2.01 ± 0.58 L/min/m2). On multivariate logistic regression analysis, chest pain [odds ratio (OR) 9.37, 95%CI (1.98-44.38), P = 0.005], increased platelet count (>242.5 × 109/L) [OR 9.03, 95%CI (2.10-38.87), P = 0.003] and pulmonary artery wall thickening [OR 7.08, 95%CI (1.44-34.89), P = 0.016] were independently associated with disease activity. CONCLUSION: Chest pain, increased platelet count, and pulmonary artery wall thickening are potential new indicators of disease activity in PTA. Patients in active stage may have lower PVR and better right heart function.

Left ventricular strain in patients with Takayasu arteritis with preserved ejection fraction: an analysis using cardiac magnetic resonance imaging feature tracking.

Background: The alteration of myocardial strain in patients with Takayasu arteritis (TAK) remains unclear. This study aimed to evaluate left ventricular (LV) stain in patients with TAK and preserved left ventricular ejection fraction (pLVEF) using cardiac magnetic resonance imaging feature tracking (CMR-FT) to analyze risk factors for impaired LV strain and to compare the baseline difference of LV strain between patients with reduced and nonreduced LVEF at 6-month follow-up. Methods: In all, 51 patients with TAK and 30 healthy controls were prospectively enrolled. All participants underwent multiple short- and long-axis cine scans with true fast imaging with steady-state precession sequence. In this observational study, LV global and regional longitudinal, circumferential, and radial strain and their strain rates were analyzed with FT on cine images. The relationship between LV strain and clinical data was explored. The baseline LV strain between patients with TAK and reduced and nonreduced LVEF was compared using transthoracic echocardiography (TTE) at the 6-month follow-up. Results: Patients with TAK with pLVEF showed a decline in baseline global longitudinal peak strain (GLS) [TAK (-13.35%±3.11%) vs. controls (-14.77%±1.74%), P=0.021] and circumferential peak strain (GCS) [TAK (-21.46%±2.66%) vs. controls (-22.75%±2.57%), P=0.027] in comparison with normal controls. The longitudinal peak strain (LPS) in the apical (P=0.003) and midventricular regions (P=0.027) and the circumferential peak strain (CPS) in the basal (P=0.021) and midventricular regions (P=0.008) also decreased in patients with TAK. Patients with pulmonary hypertension (PH) or myocardial late gadolinium enhancement (LGE) showed a greater reduction in strain compared with those without PH or LGE. GLS showed a negative association with erythrocyte sedimentation rate (ESR), while GCS showed a positive association with disease duration. In the 30 patients who were followed up, the baseline global and apical circumferential diastolic peak strain rates (DPSR) in patients with reduced LVEF were higher than those in patients without reduced LVEF. Conclusions: In patients with TAK and pLVEF, CMR-FT indicated that both global and segmental myocardial strain decreased. PH, male gender, long disease duration, elevated ESR, and myocardial LGE were associated with declined LV strain. Baseline increased circumferential DPSR may be associated with the decline in LVEF during follow-up.

Delayed contrast-enhanced magnetic resonance imaging enables detection of pulmonary artery lesions in Takayasu's arteritis.

Background: Delayed contrast-enhanced magnetic resonance imaging (DE-MRI) is a useful technique to identify arterial wall inflammation. The aim of this study was to explore the value of DE-MRI in the evaluation of pulmonary artery (PA) lesions in Takayasu's arteritis (TAK) compared with 18F-fuorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). Methods: Patients with TAK were recruited for this prospective, observational study. Imaging and clinical assessments were performed concurrently. Only thoracic arteries were evaluated, and they were divided into 18 segments per person. All arterial lesions were evaluated using both PET/CT and DE-MRI. Correlations between both methods were assessed in the PA and thoracic aorta. A receiver operating characteristic (ROC) curve was used to analyze the value of imaging features in detecting disease activity based on National Institutes of Health (NIH) criteria. Results: A total of 24 patients contributed 432 arterial segments. Using PET/CT, correlations between arterial wall DE, thickening, and edema in the PA were 84.52%, 67.92%, and 58.33%, respectively, with Cohen's kappa =0.69, 0.30, and 0.13, respectively; for the thoracic aorta, the values were 86.38%, 80.00%, and 75.92%, respectively, with Cohen's kappa =0.71, 0.52, and 0.372, respectively. There was a significant difference in the incidence of wall DE between the PA and thoracic aorta in patients with clinically active TAK (χ2=6.85, P=0.009). DE-MRI presented a higher area under the curve [area under the curve (AUC); 0.729, P=0.047] than wall thickening and edema in the detection of TAK activity. The wall DE combined with erythrocyte sedimentation rate (ESR) showed improved efficiency (AUC: 0.858, P=0.003). Conclusions: DE-MRI displays appreciable correlations with PET/CT findings and allows for the detection of PA inflammation in patients with TAK; it shows higher values in the thoracic aorta than in the PA. The combination of wall DE and ESR can improve the efficiency of assessing disease status.

Pulmonary artery imaging with 68 Ga-FAPI-04 in patients with chronic thromboembolic pulmonary hypertension.

BACKGROUND: The feasibility and significance of imaging pulmonary artery (PA) remodeling with 68 Ga-fibroblast activating protein inhibitor (FAPI) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) have not yet been addressed. METHODS: 68 Ga-FAPI-04 uptake in the PA and ascending artery was evaluated in 13 patients with CTEPH and 13 matched non-CTEPH controls. The correlations of PA 68 Ga-FAPI-04 uptake and remodeling parameters derived from right heart catheterization (RHC) were analyzed. RESULTS: Of the 13 patients with CTEPH, nine (69%) showed visually enhanced 68 Ga-FAPI-04 uptake, whereas none of the control subjects had increased 68 Ga-FAPI-04 uptake in the PA. The prevalence of enhanced uptake in the main, lobar, and segmental PAs was 45% (17/38), 33% (16/48), and 28% (44/159), respectively. 68 Ga-FAPI-04 activity in the PA was positively correlated with pulmonary arterial diastolic pressure (r = 0.571, P = 0.041). CONCLUSION: 68 Ga-FAPI-04 has the potential for imaging fibroblast activation in the PA wall, and 68 Ga-FAPI-04 activity in PA is positively correlated with pulmonary arterial diastolic pressure.

Long-term Outcomes and Predictors of Chronic Thromboembolic Pulmonary Hypertension After Pulmonary Endarterectomy.

BACKGROUND: Pulmonary endarterectomy (PEA) is the preferred treatment for CTEPH patients which can significantly improve symptoms and pulmonary hemodynamics. Therefore, this retrospective study evaluated the long-term outcomes after pulmonary endarterectomy (PEA) and analyze the predictors of long-term outcomes for chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: From 2002-2020, 76 CTEPH patients successfully discharged after PEA in Beijing Chaoyang Hospital were followed-up by scheduled clinical visits or telephone interviews. The follow-up time lasted for 18 years and median time was 7.29 years. RESULTS: The survival rate at 1,3,5,10,15 years postoperatively was 100.00%, 97.10%, 95.40%, 89.80% and 82.90%, respectively. Multivariate logistics regression analysis showed that postoperative mPAP (hazard ratio: 1.144; 95%confidence interval: 1.018-1.285; P = 0.023) was associated with a higher risk of late death, right atrium right and left diameters (hazard ratio: 1.113; 95%confidence interval, 1.006-1.231; P = 0.038) were associated with a higher risk of major adverse events. CONCLUSION: Pulmonary endarterectomy is an effective way to treat CTEPH. Long-term outcome is excellent for patients who undergoing pulmonary endarterectomy who survived from peri-operation time. Postoperative mPAP is a significant prognostic factor for long-term death and right atrium right and left diameters is a significant prognostic factor for major adverse events. That shows patients with high postoperative mPAP and right atrium right and left diameter should be followed up closely.

Single-cell RNA-sequencing and microarray analyses to explore the pathological mechanisms of chronic thromboembolic pulmonary hypertension.

Objective: The present study aimed to explore the pathological mechanisms of chronic thromboembolic pulmonary hypertension (CTEPH) using a gene chip array and single-cell RNA-sequencing (scRNA-seq). Materials and methods: The mRNA expression profile GSE130391 was downloaded from the Gene Expression Omnibus database. The peripheral blood samples of five CTEPH patients and five healthy controls were used to prepare the Affymetrix microRNA (miRNA) chip and the Agilent circular RNA (circRNA) chip. The pulmonary endarterectomized tissues from five CTEPH patients were analyzed by scRNA-seq. Cells were clustered and annotated, followed by the identification of highly expressed genes. The gene chip data were used to identify disease-related mRNAs and differentially expressed miRNAs and circRNAs. The protein-protein interaction (PPI) network and the circRNA-miRNA-mRNA network were constructed for each cell type. Results: A total of 11 cell types were identified. Intersection analysis of highly expressed genes in each cell type and differentially expressed mRNAs were performed to obtain disease-related genes in each cell type. TP53, ICAM1, APP, ITGB2, MYC, and ZYX showed the highest degree of connectivity in the PPI network of different types of cells. In addition, the circRNA-miRNA-mRNA network for each cell type was constructed. Conclusion: For the first time, the key mRNAs, miRNAs, and circRNAs, as well as their possible regulatory relationships, during the progression of CTEPH were analyzed using both gene chip and scRNA-seq data. These findings may contribute to a better understanding of the pathological mechanisms of CTEPH.

Diagnostic value of miRNA expression and right ventricular echocardiographic functional parameters for chronic thromboembolic pulmonary hypertension with right ventricular dysfunction and injury.

BACKGROUND: We aimed to establish the relationships between the expression of microRNAs (miRNAs) and echocardiographic right ventricular (RV) function parameters, and to explore the effectiveness and clinical value of miRNA expression in predicting RV injury and dysfunction in patients with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: In this retrospective study, clinical data were collected from eight CTEPH patients and eight healthy individuals. RV parameters on echocardiography were analyzed, and the expression levels of specific miRNAs were measured by quantitative real-time PCR. Correlation analysis was performed on structural and functional RV parameters and five candidate miRNAs (miR-20a-5p, miR-17-5p, miR-93-5p, miR-3202 and miR-665). The diagnostic value of RV functional parameters and miRNAs expression was assessed by receiver operating characteristic (ROC) curve analysis and C statistic. RESULTS: Among the tested miRNAs, miR-20a-5p expression showed the best correlation with echocardiographic RV functional parameters (P < 0.05), although the expression levels of miR-93-5p, miR-17-5p and miR-3202 showed positive associations with some RV parameters. ROC curve analysis demonstrated the ability of miR-20a-5p expression to predict RV dysfunction, with a maximum area under the curve of 0.952 (P = 0.003) when the predicted RV longitudinal strain was less than -20%. The C index for RV dysfunction prediction by the combination of miRNAs (miR-20a-5p, miR-93-5p and miR-17-5p) was 1.0, which was significantly larger than the values for miR-93-5p and miR-17-5p individually (P = 0.0337 and 0.0453, respectively). CONCLUSION: Among the tested miRNAs, miR -20a-5p, miR -93-5p and miR -17-5p have potential value in the diagnosis of CTEPH based on the correlation between the abnormal expression of these miRNAs and echocardiographic parameters in CTEPH patients. miR-20a-5p showed the strongest correlation with echocardiographic RV functional parameters. Moreover, expression of a combination of miRNAs seemed to show excellent predictive power for RV dysfunction.

Stimulation of both inspiratory and expiratory muscles versus diaphragm-only paradigm for rehabilitation in severe chronic obstructive pulmonary disease patients: a randomized controlled pilot study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD), a progressive lung disease, might improve with neuromuscular electrical stimulation. No trials on inspiratory plus expiratory neuromuscular electrical stimulation have been conducted yet. AIM: The aim of this study was to evaluate the safety and effectiveness of inspiratory plus expiratory neuromuscular electrical stimulation in subjects with severe COPD. DESIGN: This was a multicenter, prospective, randomized controlled trial. SETTING: The subjects were outpatients enrolled from Beijing Chao-Yang Hospital affiliated with Capital Medical University, Tianjin Chest Hospital, and the First Hospital of Hebei Medical University. POPULATION: Subjects had stable COPD with severe respiratory impairment. METHODS: Using a computer statistical software, 120 stable subjects were randomly allocated (1:1) to receive inspiratory plus expiratory neuromuscular electrical stimulation (study group) and diaphragm pacing (control group). Demographic and clinical data were collected before, and after 2, and 4 weeks of the trial. The intention-to-treat analysis was conducted. The primary outcome was to analyze the changes in functional exercise capacity, estimated as six-minute walk distance (6MWD), following electrical stimulation for 4 weeks. The secondary outcomes were changes in modified Medical Research Council score, forced expiratory volume in 1 second (FEV1), FEV1% predicted, and FEV1 ratio forced vital capacity (FEV1/FVC) following electrical stimulation for 4 weeks. RESULTS: The change in 6MWD was greater in the study group (65.53±39.45 m) than in the control group (26.66±32.65 m). The mean between-group difference at the fourth week was 29.07 m (95% confidence interval, 16.098-42.035; P<0.001). There were no significant between-group differences in the secondary outcomes after 4 weeks of electrical stimulation. For GOLD-4 COPD subjects, FEV1 and FEV1/FVC improved in the study group (P<0.05). No electrical stimulation-related serious adverse events were observed in either group. CONCLUSIONS: 6MWD were increased significantly, without adverse events, after four weeks of treatment of inspiratory plus expiratory neuromuscular electrical stimulation in stable patients with severe COPD, suggesting that this protocol benefits COPD rehabilitation. CLINICAL REHABILITATION IMPACT: The results of this study suggest that the simultaneous use of inspiratory plus expiratory neuromuscular electrical stimulation as an adjunct therapy may improve the functional exercise capacity of severe stable COPD subjects.

Examining the Development of Chronic Thromboembolic Pulmonary Hypertension at the Single-Cell Level.

BACKGROUND: The mechanism of chronic thromboembolic pulmonary hypertension (CTEPH) is known to be multifactorial but remains incompletely understood. METHODS: In this study, single-cell RNA sequencing, which facilitates the identification of molecular profiles of samples on an individual cell level, was applied to investigate individual cell types in pulmonary endarterectomized tissues from 5 patients with CTEPH. The order of single-cell types was then traced along the developmental trajectory of CTEPH by trajectory inference analysis, and intercellular communication was characterized by analysis of ligand-receptor pairs between cell types. Finally, comprehensive bioinformatics tools were used to analyze possible functions of branch-specific cell types and the underlying mechanisms. RESULTS: Eleven cell types were identified, with immune-related cell types (T cells, natural killer cells, macrophages, and mast cells) distributed in the left (early) branch of the pseudotime tree, cancer stem cells, and CRISPLD2+ cells as intermediate cell types, and classic disease-related cell types (fibroblasts, smooth muscle cells, myofibroblasts, and endothelial cells) in the right (later) branch. Ligand-receptor interactions revealed close communication between macrophages and disease-related cell types as well as between smooth muscle cells and fibroblasts or endothelial cells. Moreover, the ligands and receptors were significantly enriched in key pathways such as the PI3K/Akt signaling pathway. Furthermore, highly expressed genes specific to the undefined cell type were significantly enriched in important functions associated with regulation of endoplasmic reticulum stress. CONCLUSIONS: This single-cell RNA sequencing analysis revealed the order of single cells along a developmental trajectory in CTEPH as well as close communication between different cell types in CTEPH pathogenesis.

Imaging of cardiac fibroblast activation in patients with chronic thromboembolic pulmonary hypertension.

PURPOSE: The aim of this study was to explore the association of cardiac fibroblast activation with clinical parameters and cardiovascular magnetic resonance (CMR) imaging parameters in patients with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Thirteen CTEPH patients were prospectively enrolled. All of the patients underwent cardiac 68Gallium-labelled fibroblast activation protein inhibitor (68 Ga-FAPI-04)-positron emission tomography/computed tomography (PET/CT), right heart catheterisation, and echocardiography, and 11 of them additionally underwent CMR. Thirteen control subjects were selected to establish the normal range of cardiac 68 Ga-FAPI-04 uptake. Cardiac 68 Ga-FAPI-04 uptake higher than that in the blood pool was defined as abnormal. The global and segmental maximum standardised uptake values (SUVmax) of the right ventricle (RV) were measured and further expressed as target-to-background ratio (TBRRV) with left ventricular lateral wall activity as background. Late gadolinium enhancement (LGE) was visually evaluated, and native-T1 times, enhanced-T1 times, and extracellular volume (ECV) were quantitatively measured. RESULTS: Ten CTEPH patients (77%) had abnormal 68 Ga-FAPI-04 uptake in RV, mainly located in the free wall, which was significantly higher than that in controls (TBRRV: 2.4 ± 0.9 vs 1.0 ± 0.1, P < 0.001). The TBRRV correlated positively with the thickness of RV wall (r = 0.815, P = 0.001) and inversely with RV fraction area change (RVFAC) (r = - 0.804, P = 0.001) and tricuspid annular plane systolic excursion (TAPSE) (r = - 0.678, P = 0.011). No correlation was found between 68 Ga-FAPI-04 activity and CMR imaging parameters. CONCLUSION: Fibroblast activation in CTEPH, measured by 68 Ga-FAPI-04 imaging, is mainly localised in the RV free wall. Enhanced fibroblast activation reflects the thickening of the RV wall and decreased RV contractile function.

Haemodynamic effects of riociguat in CTEPH and PAH: a 10-year observational study.

BACKGROUND: Long-term treatment with riociguat has been shown to enhance exercise capacity in patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH). This study sought to evaluate the long-term haemodynamic effects of riociguat in patients with PAH and inoperable CTEPH. METHODS: During this single-centre long-term observational study, riociguat was administered at a three-times-daily dose of up to 2.5 mg. The primary outcome was pulmonary vascular resistance (PVR). The secondary outcomes included mean pulmonary arterial pressure (PAP), cardiac index, mortality, clinical worsening events, 6-min walk distance (6MWD) and World Health Organization functional class (WHO FC). RESULTS: 37 patients (CTEPH n=19; PAH n=18) were included. The median follow-up period was 96 months. The survival estimates for all the patients at 1/3/5/8 years were 0.97/0.86/0.72/0.61, without significant differences between patients with CTEPH and PAH. At the final data cut-off, PVR decreased (1232±462 dyn·s·cm-5 versus 835±348 dyn·s·cm-5, p<0.001), cardiac index increased (1.7±0.4 L·min-1·m-2 versus 2.4±0.5 L·min-1·m-2, p<0.001), 6MWD increased by 43.1±59.6 m, and WHO FC improved/stabilised/worsened in 40%/35%/25% of patients versus baseline. Improvement in PAP was not shown. Compared with patients in WHO FC I/II and III/IV at baseline, the 8-year clinical worsening-free survival estimates were 0.51 versus 0.19 (p=0.026). CONCLUSIONS: Riociguat improved PVR and cardiac index for up to 8 years, but not PAP. WHO FC may have certain predictive value for the long-term prognosis.

Right Ventricular Function Predicts Adverse Clinical Outcomes in Patients With Chronic Thromboembolic Pulmonary Hypertension: A Three-Dimensional Echocardiographic Study.

Background: Right ventricular (RV) function plays a vital role in the prognosis of patients with chronic thromboembolic pulmonary hypertension (CTEPH). We used new machine learning (ML)-based fully automated software to quantify RV function using three-dimensional echocardiography (3DE) to predict adverse clinical outcomes in CTEPH patients. Methods: A total of 151 consecutive CTEPH patients were registered in this prospective study between April 2015 and July 2019. New ML-based methods were used for data management, and quantitative analysis of RV volume and ejection fraction (RVEF) was performed offline. RV structural and functional parameters were recorded using 3DE. CTEPH was diagnosed using right heart catheterization, and 62 patients underwent cardiac magnetic resonance to assess right heart function. Adverse clinical outcomes were defined as PH-related hospitalization with hemoptysis or increased RV failure, including conditions requiring balloon pulmonary angioplasty or pulmonary endarterectomy, as well as death. Results: The median follow-up time was 19.7 months (interquartile range, 0.5-54 months). Among the 151 CTEPH patients, 72 experienced adverse clinical outcomes. Multivariate Cox proportional-hazard analysis showed that ML-based 3DE analysis of RVEF was a predictor of adverse clinical outcomes (hazard ratio, 1.576; 95% confidence interval (CI), 1.046~2.372; P = 0.030). Conclusions: The new ML-based 3DE algorithm is a promising technique for rapid 3D quantification of RV function in CTEPH patients.