Evaluating the efficacy of balloon pulmonary angioplasty using quantitative analysis of SPECT pulmonary ventilation/perfusion scintigraphy in patients with chronic thromboembolic pulmonary hypertension.

Background: Single-photon emission computed tomography (SPECT) ventilation perfusion imaging is the main imaging method for the diagnosis of pulmonary embolism, and its application in the diagnosis and efficacy evaluation of chronic thromboembolic pulmonary hypertension (CTEPH) has been paid more and more attention. In recent years, with the development of computer software technology, ventilation/perfusion (V/Q) imaging quantitative analysis technology has become more and more mature. The objective of this study was to investigate the utility of quantitative analysis of pulmonary V/Q scintigraphy in evaluating the efficacy of balloon pulmonary angioplasty (BPA) in patients with CTEPH. Methods: In this retrospective analysis, we collected data of patients diagnosed with CTEPH who underwent BPA at the China-Japan Friendship Hospital from April 2018 to September 2020. The sample consisted of 23 males and 28 females, with an average age of 55.1±12.7 years. All patients underwent V/Q scintigraphy within one week before surgery, and we reviewed the pulmonary angiography within 1-3 months following the last BPA procedure. We repeated V/Q scintigraphy within 1 week before or after the pulmonary angiography, at the time of collecting clinical and hemodynamic parameters of these patients. We divided the patients into two groups based on the presence of residual pulmonary hypertension post-surgery and compared the pre- and post-operative quantitative pulmonary perfusion defect percentage scores (PPDs%) using the t-test. Results: In all, 102 V/Q scintigraphy scans were performed in 51 patients. The quantitative PPDs% were positively correlated with the hemodynamic indexes mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and mean right ventricular pressure (RVP) (r=0.605, 0.391, and 0.464, respectively, all P<0.001) and negatively correlated with the 6-minute walking distance (6MWD) (r=-0.254, P=0.010). The average preoperative quantitative PPDs% were (49.0±15.6)% which significantly decreased to (33.5±13.9)% after surgery (t=11.249, P<0.001). The preoperative quantitative PPDs% were (54.7±15.7)% and (44.0±13.8)% in the residual pulmonary hypertension group and the non-residual pulmonary hypertension group, respectively (t=2.599, P=0.012). The postoperative quantitative PPDs% were (41.5±12.5)% and (26.3±11.0)%, in the residual pulmonary hypertension group and the non-residual pulmonary hypertension group, respectively (t=4.647, P<0.001). Conclusions: In this study, we found that quantitative analysis of SPECT pulmonary V/Q scintigraphy adequately reflected the pulmonary artery pressure and clinical status in patients with CTEPH. Our results demonstrate its definite utility in predicting residual pulmonary hypertension and in evaluating the postoperative efficacy of BPA in patients with CTEPH.

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

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 (sPAPEcho, mPAPEcho) and measured the left ventricular internal diameter at end diastole (LVIDd). sPAPEcho/LVIDd and mPAPEcho/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, mPAPEcho/LVIDd moderately correlated with PVR (r = 0.51, p < 0.0001). There was a better correlation between PVR and sPAPEcho/LVIDd (r = 0.61, p < 0.0001). sPAPEcho/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 sPAPEcho/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 sPAPEcho/LVIDd and mPAPEcho/LVIDd significantly decreased after PEA (both p < 0.0001). The sPAPEcho/LVIDd and mPAPEcho/LVIDd reduction rate (ΔsPAPEcho/LVIDd and ΔmPAPEcho/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 sPAPEcho/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.

The accuracy and influencing factors of Doppler echocardiography in estimating pulmonary artery systolic pressure: comparison with right heart catheterization: a retrospective cross-sectional study.

BACKGROUND: Noninvasive assessment of pulmonary artery systolic pressure by Doppler echocardiography (sPAPECHO) has been widely adopted to screen for pulmonary hypertension (PH), but there is still a high proportion of overestimation or underestimation of sPAPECHO. We therefore aimed to explore the accuracy and influencing factors of sPAPECHO with right heart catheterization (RHC) as a reference. METHODS: A total of 218 highly suspected PH patients who underwent RHC and echocardiography within 7 days were included. The correlation and consistency between tricuspid regurgitation (TR)-related methods and RHC results were tested by Pearson and Bland-Altman methods. TR-related methods included peak velocity of TR (TR Vmax), TR pressure gradient (TR-PG), TR mean pressure gradient (TR-mPG), estimated mean pulmonary artery pressure (mPAPECHO), and sPAPECHO. With mPAP ≥ 25 mm Hg measured by RHC as the standard diagnostic criterion of PH, the ROC curve was used to compare the diagnostic efficacy of sPAPECHO with other TR-derived parameters. The ratio (sPAPECHO-sPAPRHC)/sPAPRHC was calculated and divided into three groups as follows: patients with an estimation error between - 10% and + 10% were defined as the accurate group; patients with an estimated difference greater than + 10% were classified as the overestimated group; and patients with an estimation error greater than - 10% were classified as the underestimated group. The influencing factors of sPAPECHO were analyzed by ordinal regression analysis. RESULTS: sPAPECHO had the highest correlation coefficient (r = 0.781, P < 0.001), best diagnostic efficiency (AUC = 0.98), and lowest bias (mean bias = 0.07 mm Hg; 95% limits of agreement, - 32.08 to + 32.22 mm Hg) compared with other TR-related methods. Ordinal regression analysis showed that TR signal quality, sPAPRHC level, and pulmonary artery wedge pressure (PAWP) affected the accuracy of sPAPECHO (P < 0.05). Relative to the good signal quality, the OR values of medium and poor signal quality were 0.26 (95% CI: 0.14, 0.48) and 0.23 (95% CI: 0.07, 0.73), respectively. Compared with high sPAPRHC level, the OR values of low and medium sPAPRHC levels were 21.56 (95% CI: 9.57, 48.55) and 5.13 (95% CI: 2.55, 10.32), respectively. The OR value of PAWP was 0.94 (95% CI: 0.89, 0.99). TR severity and right ventricular systolic function had no significant effect on the accuracy of sPAPECHO. CONCLUSIONS: In this study, we found that all TR-related methods, including sPAPECHO, had comparable and good efficiency in PH screening. To make the assessment of sPAPECHO more accurate, attention should be paid to TR signal quality, sPAPRHC level, and PAWP.

Analysis of right ventricular flow with 4-dimensional flow cardiovascular magnetic resonance imaging in patients with pulmonary arterial hypertension.

BACKGROUND: Cardiac flow closely interact with function, however, the correlation of right ventricular (RV) flow and function remains unknown, thus our objective is to observe right ventricular flow with four-dimensional phase-contrast cardiovascular magnetic resonance imaging (4D flow CMR) in patients with pulmonary arterial hypertension (PAH) and to analyze flow components with RV function and hemodynamics. METHODS: This study retrospectively enrolled 30 patients with PAH (mean age: 49±13 years, 16 females) and 14 age- and sex-matched healthy volunteers as controls (mean age: 44±12 years, 9 females). All patients who underwent CMR and right heart catheterization (RHC) within 1 week between January 2019 and July 2020 were included. Hemodynamics were measured with RHC. RV flow components, including the percentages of direct flow (RVPDF), retained inflow (RVPRI), delayed ejection flow (RVPDEF) and residual volume (RVPRVo) were quantified using 4D flow CMR. The associations between RV flow components and other CMR metrics, clinical data, and hemodynamics were analyzed by Spearman's correlation analysis. RESULTS: In patients with PAH, RVPDF was decreased and RVPRVo was increased compared with the normal control group. The sum of RVPDF and RVPDEF RV was significantly correlated with RV ejection fraction (RVEF) (r=0.802, P<0.001), and there was no notable difference between RVEF and the sum of RVPDF and RVPDEF (t=0.251, P=0.831). Both RVPDF and RVPRVo were correlated (in opposite directions) with the RV end-diastolic volume index, RV end-systolic volume index, RV global longitudinal strain, and RVEF. RVPDF was negatively correlated with pulmonary vascular resistance (PVR), and positively correlated with cardiac output and cardiac index. RVPRVo was positively correlated with PVR and negatively correlated with cardiac output and cardiac index. CONCLUSIONS: RV blood flow components qualified with 4D flow CMR is a valuable noninvasive method for the assessment of RV function and hemodynamics in patients with PAH.

Regional right ventricular longitudinal systolic strain for detection of severely impaired right ventricular performance in pulmonary hypertension.

OBJECTIVES: Right ventricular (RV) function is identified as a key determinant of the outcome in patients with pulmonary hypertension (PH). Several studies have assessed the role of peak global longitudinal RV strain in PH patients; however, less emphasis was given to the RV regional longitudinal strain. The aim of this study was to evaluate the regional RV systolic strain in PH patients and investigate the relationship of these parameters with the severity of PH. METHODS: RV regional longitudinal peak systolic strain (LPSS) and strain rate (LPSSR) were measured using speckle tracking echocardiography on 100 patients with PH who underwent right heart catheterization, and 29 control subjects. Severe PH was identified by a decreased cardiac index (CI) (<2.0 L/min/m2 ). RESULTS: LPSS and LPSSR of the RV free wall were significantly lower in PH patients than control subjects, especially when comparing the basal and mid regions (P < .001). When comparing severe PH and nonsevere PH, basal and mid LPSS and LPSSR were significantly lower (P < .001). RV free wall mid LPSSR correlated with CI (r = -.703, P < .001). In the multiple logistic regression analysis, mid LPSSR was identified as an independent predictor of severe PH (odds ratio 1.82; 95% confidential interval 1.39-2.40; P < .001). In the receiver operating characteristics curve analysis, a cutoff value of mid LPSSR of -0.92 s-1 predicted severe PH, with a sensitivity and specificity of 75.0% and 93.7%, respectively (AUC = 0.889, P < .001). CONCLUSIONS: RV free wall mid longitudinal peak systolic strain rate may be useful for the detection of severely impaired RV performance in PH.

Awareness and management of pulmonary embolism among physicians in China: a nationwide cross-sectional study.

Pulmonary embolism (PE) is a leading cause of cardiovascular mortality. We intended to evaluate the awareness and management status of PE among Chinese physicians and provide the basis for establishing Chinese clinical guidelines on PE. We designed a nationwide survey to collect data on physicians' awareness of diagnosis, treatment and follow-up on PE. The questionnaires were distributed to physicians during offline academic meetings and by the online platforms from August 2016 to October 2016. Also, results were sub-grouped by age, hospital grades, departments and trained or not. A total of 2954 valid questionnaires were collected. We observed that there were several defects in the management of PE among Chinese physicians. First, a considerable proportion of physicians chose the incorrect clinical prediction rules for acute PE. Second, a considerable percentage of hospitals could not carry out computed tomographic pulmonary angiography (22.4%) or ventilation-perfusion scintigraphy (65.2%). Third, only a few physicians knew the use of new oral anticoagulants clearly (33.4%). Fourth, only 49% of physicians achieved follow-up management in over half of their patients. Additionally, physicians in the tertiary hospitals, aged > 35 years, trained and from respiratory department have a better knowledge of the management of PE. In conclusion, our survey demonstrates the enhancement of PE-related trainings, especially for physicians in lower-level hospitals, aged ≤ 35 years and from non-respiratory department, can help to improve the management of PE in Chinese physicians. And our study also highlights the need for the establishment of national guidelines for the management of PE in China.

The value of speckle-tracking echocardiography in identifying right heart dysfunction in patients with chronic thromboembolic pulmonary hypertension.

Right ventricular (RV) function is a significantly important factor in the determination of the prognosis of chronic thromboembolic pulmonary hypertension (CTEPH) patients. Speckle-tracking echocardiography (STE) is an angle-independent new technique for quantifying myocardial deformation that is capable of providing data on multiple parameters including longitudinal and transverse information of the myocardium. In the present study, we aimed to study the advantages of STE-derived parameters in identifying RV dysfunction in CTEPH patients. Sixty CTEPH patients (mean age: 55 years ± 13 years; 25 males) and 30 normal controls (mean age: 54 years ± 14 years; 14 males) were enrolled in this study. RV free wall (RVFW) systolic peak longitudinal strain (LS) including the basal, mid-, and apical-segments and the basal longitudinal and transverse displacement (basal-DL and basal-DT) were measured by STE. Global LS (GLS) of the RV was calculated by averaging the LS value of the 3 segments of RVFW. Clinical data of CTEPH patients were collected. CTEPH patients were divided into 2 subgroups according to the World Health Organization function classification. Clinical right heart failure (RHF) was defined as the presence of symptoms of heart failure and signs of systemic circulation congestion during hospitalization. The apical segment LS of the RVFW was lower than that in the basal and mid-segments in the control group (P < 0.001), but no significant difference was found among the 3 segments of LS in the CTEPH group (P = 0.263). When we used the cutoff value recommended by the American Society of Echocardiography guidelines to identify abnormal RV function, 30 CTEPH patients (50%) by tricuspid annular plane systolic excursion (TAPSE), 42 patients (70%) by fractional area change (FAC), 20 patients (33.33%) by RV index of myocardial performance (RVIMP), and 46 patients (77%) patients by GLS were determined to have abnormal RV function, respectively. Among multiple RV function indicators, TAPSE, FAC, GLS, basal-DL, and N-terminal pronatriuretic B-type natriuretic peptide showed significant differences between CTEPH patients with mild (WHO II) and severe symptoms (WHO III/IV) (all P < 0.001), while RVIMP and basal-DT showed no significant difference (P = 0.188 and P = 0.394, respectively). Pearson correlation analysis showed that GLS has no correlation with sPAP as evaluated by echocardiography in CTEPH patients (r = - 0.079, P = 0.574), and a weak to moderate correlation with RA area (r = 0.488, P = 0.000), the RV diameter (r = 0.429, P = 0.001), and the RVFW thickness (r = 0.344, P = 0.009). On receiver operating characteristic analysis, GLS has the largest area under the curve to identify RHF when the cutoff value was - 13.45%, the sensitivity was 78.2%, and the specificity was 84.6%, separately. Our study demonstrated that the depression of regional LS of RVFW is more pronounced in the basal and middle segments in CTEPH patients. Also, the longitudinal movement is much more important than the transverse movement when evaluating RV systolic function. As compared with conventional parameters, RVFW GLS showed more sensitivity to identify abnormal RV function and had the largest AUC for identifying RHF. Additionally, GLS showed no correlation with sPAP and a weak correlation with right heart morphological parameters in our CTEPH cohort.

Serum Bilirubin and 6-min Walk Distance as Prognostic Predictors for Inoperable Chronic Thromboembolic Pulmonary Hypertension: A Prospective Cohort Study.

BACKGROUND: Inoperable chronic thromboembolic pulmonary hypertension (CTEPH) is a severe clinical syndrome characterized by right cardiac failure and possibly subsequent liver dysfunction. However, whether serum markers of liver dysfunction can predict prognosis in inoperable CTEPH patients has not been determined. Our study aimed to evaluate the potential role of liver function markers (such as serum levels of transaminase, bilirubin, and gamma-glutamyl transpeptidase [GGT]) combined with 6-min walk test in the prediction of prognosis in patients with inoperable CTEPH. METHODS: From June 2005 to May 2013, 77 consecutive patients with inoperable CTEPH without confounding co-morbidities were recruited for this prospective cohort study. Baseline clinical characteristics and 6-min walk distance (6MWD) results were collected. Serum biomarkers of liver function, including levels of aspartate aminotransferase, alanine aminotransferase, GGT, uric acid, and serum bilirubin, were also determined at enrollment. All-cause mortality was recorded during the follow-up period. RESULTS: During the follow-up, 22 patients (29%) died. Cox regression analyses demonstrated that increased serum concentration of total bilirubin (hazard ratio [HR] = 7.755, P < 0.001), elevated N-terminal of the prohormone brain natriuretic peptide (HR = 1.001, P = 0.001), decreased 6MWD (HR = 0.990, P < 0.001), increased central venous pressure (HR = 1.074, P = 0.040), and higher pulmonary vascular resistance (HR = 1.001, P = 0.018) were associated with an increased risk of mortality. Serum concentrations of total bilirubin (HR = 4.755, P = 0.007) and 6MWD (HR = 0.994, P = 0.017) were independent prognostic predictors for CTEPH patients. Patients with hyperbilirubinemia (≥23.7 µmol/L) had markedly worse survival than those with normobilirubinemia. CONCLUSION: Elevated serum bilirubin and decreased 6MWD are potential predictors for poor prognosis in inoperable CTEPH.

Clinical features and imaging findings in pulmonary capillary hemangiomatosis: report of two cases and a pooled analysis.

BACKGROUND: Pulmonary capillary hemangiomatosis (PCH) is a rare disease and no Chinese case has been reported yet. The disease is often misdiagnosed and its clinical characteristics are incompletely described. The aim of this study was to describe two Chinese cases and to clarify the clinical and radiographic parameters of patients with PCH. METHODS: Two PCH cases were presented and other cases were searched from the English literature. All available clinical and radiographic data were collected from 62 literature reported PCH cases. A pooled analysis of total 64 cases was made. RESULTS: Dyspnea and hemoptysis were the most common clinical symptoms of PCH. Pulmonary hypertension (PH) was found in 78% of the reported cases. PCH typically showed characteristic diffuse or patchy ground-glass opacities (GGOs) and/or multiple ill-defined centrilobular nodules in the computed tomography. CONCLUSIONS: The diagnosis of PCH requires a high clinical suspicion. However, both clinical presentations and radiographic studies often provide clues to the diagnosis, which may prompt early lung biopsy for a definite diagnosis.

Prevalence of deep venous thrombosis in patients with acute exacerbation of chronic obstructive pulmonary disease.

BACKGROUND: Acute exacerbation of chronic obstructive pulmonary disease (COPD) is always associated with a high incidence and mortality. Because of the presence of some concomitant risk factors such as immobilization, bronchial superinfection, patients who are admitted for acute exacerbations of COPD are generally considered to be at moderate risk for the development of venous thromboembolism. In this study, we investigated the prevalence and the clinical manifestations of deep venous thrombosis (DVT) in patients with acute exacerbation of COPD. METHODS: From March 2007 to March 2009, 520 consecutive patients were included in this study. On admission, color Doppler ultrasound of lower extremities in all cases was performed for diagnosing DVT. Patients with DVT were compared with those without DVT from such aspects as demographics, symptoms, physical signs and risk factors. RESULTS: Among the 520 patients, DVT was found in 46 cases (9.7%). In patients with DVT, the duration of hospitalization was longer (P = 0.01), and the mechanical ventilation requirement increased (P < 0.001). Other indicators for patients with more possibility of DVT were immobility exceeding 3 days (P < 0.001); pneumonia as concomitance (P = 0.01); respiratory failure type II (P = 0.013); current smoking (P = 0.001). Lower extremity pain was more common in DVT cases in comparison to those without DVT (34.8% vs. 15.2%, P = 0.01). CONCLUSIONS: The acute exacerbation of COPD patients, who were immobilized for over 3 days, complicated by pneumonia and had respiratory failure type II, had a higher risk of DVT. In addition, DVT detection awareness should be increased in cases that had a lower extremity pain.

[The oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension].

OBJECTIVE: To study the acute oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension. METHODS: Twenty-two and 24 patients who were admitted to our hospital between June 2006 and January 2009 with confirmed diagnosis of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) respectively were enrolled to this study. During right heart catheterization, the hemodynamics and oxygen kinetics were monitored at baseline and after inhaling Iloprost (20 micrograms). RESULTS: At baseline, the arterial partial pressure of oxygen (PaO2) was (63 +/- 10) mm Hg (1 mm Hg = 0.133 kPa) and (59 +/- 10) mm Hg respectively in PAH and CTEPH patients, and the oxygen delivery index (DO2I) and oxygen consumption index (VO2I) were (458 +/- 136) ml x min(-1) x m(-2) and (135 +/- 53) ml x min(-1) x m(-2) in PAH patients respectively, and (386 +/- 92) ml x min(-1) x m(-2) and (131 +/- 43) ml x min(-1) x m(-2) in CTEPH patients respectively. Three minutes after inhaling Iloprost, for PAH and CTEPH patients, the pulmonary shunt rate (Qs/Qt) all increased significantly (all P < 0.05, respectively) as well as the difference of oxygen partial pressure between pulmonary alveoli and artery (P[A-a]O2, all P < 0.05, respectively), and the arterial oxygen content (CaO2) all decreased significantly (all P < 0.05, respectively). The oxygenation parameters of mixed venous blood, oxygen extractive rate and DO2I did not change significantly, but VO2I declined to different extent. The extent of change after inhaling Iloprost for all oxygen kinetic parameters were similar between PAH and CTEPH patients. At baseline, mixed venous oxygen saturation (SvO2), venous oxygen content (CvO2) and DO2I in CTEPH patients were lower than those in PAH patients. After inhaling Iloprost, in CTEPH patients, PaO2, SvO2 and CvO2 were lower than those in PAH patients. CONCLUSION: There were hypoxemia and abnormality of oxygen kinetics in PAH and CTEPH patients. After inhaling Iloprost, pulmonary shunt increased without improvement in oxygen kinetics. Oxygenation should be monitored closely and supply oxygen supplied for CTEPH when inhaling Iloprost.

[Changes in deep venous thrombosis after thrombolytic anticoagulant therapies in acute pulmonary thromboembolism].

OBJECTIVE: To analyze the treatment effect of deep venous thrombosis (DVT) in acute pulmonary thromboembolism (PTE) with thrombolytic and anticoagulant therapy. METHODS: Post hoc analysis of data from a prospective multicenter randomized control thrombolytic and anticoagulant trial of 516 patients with acute symptomatic PTE from June 2002 to December 2004. Thrombolytic therapy was performed in patients with massive and sub-massive PTE and anticoagulant therapy was given in patients with non-massive PTE. A total of 362 patients that accepted compression ultrasonography (CUS) before and 14 days after treatment constituted this study. RESULTS: The ratio of detected DVT by CUS 14 days after treatment was reduction than that before treatment (chi2=22.667, P<0.001), but 11.6% patients had new or recurrent DVT. The rates of recanalization in thrombolysis group and anticoagulant group were 56.5% and 47.8% respectively (chi2=1.435, P=0.231). The results after three months follow up showed not recovery in 30.4% DVT patients and new or recurrent DVT in 10.4% patients. CONCLUSIONS: The normalization rate of DVT is low during 14 days treatment, and recurrence rate is high. Thrombolysis has no better rate of recanalization than anticoagulant. The prognosis of DVT hasn't improved significantly during short term treatment.

[The acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension].

OBJECTIVE: To evaluate the acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: A prospective study was made. Eighteen patients with CTEPH were enrolled. At right heart catheterisation, iloprost was inhaled at 20 microg for 10 - 15 min. Compare the value of heart rate (HR), mean blood pressure (mBP), mean pulmonary arterial hypertension (mPAP), right atrium pressure (RAP), pulmonary arterial wedge pressure (PAWP), cardiac output (CO), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), arterial partial pressure of oxygen (PaO2), arterial oxygen saturation (SaO2), mixed venous saturation (SvO2), pulmonary shunt fraction (Qs/Qt), alveolar-arterial partial pressure of oxygen [P ( A-a) O2] before to after inhaled iloprost in these patients. RESULTS: Significant changes (before to after inhalation): mPAP, (53 +/- 11) to (47 +/- 14) mm Hg (P < 0.01); PVR, (821 +/- 194) to (681 +/- 199) dyn x s x cm(-5) (P < 0.01); RAP, (10 +/- 6) to (7 +/- 6) mm Hg (P < 0.01). However, HR, PAWP, mBP, CO and SVR had no significant changes. At the same time, inhaled iloprost significantly decreased PaO2 from (58 +/- 11) to (52 +/- 6) mm Hg (P < 0.01) and increased Qs/Qt from (27 +/- 11)% to (33 +/- 9)% (P < 0.01)and P(A-a) O2 from (86 +/-39) to (93 +/- 38) mm Hg (P < 0.01). CONCLUSION: Inhaled iloprost might instantly improve hemodynamics in CTEPH, but at the same time it increased arteriovenous shunts which resulted in lower PaO2.