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Background: Patients with chronic thromboembolic pulmonary hypertension (CTEPH) present with a decreased oxygen uptake, however, the prognostic relevance of oxygen uptake (VO 2 ) in inoperable CTEPH is unknown., Methods: Patients with inoperable CTEPH were retrospectively analyzed. All patients were assessed by means of right heart catheterisation and cardio pulmonary exercise testing in semisupine position with a 30 Watt increment step-protocol., Results: One-hundred and fifty-one patients (82 female (54.3%), mean age 61 ± 12.4 years) presented with a mean pulmonary arterial pressure of 40.2 ± 14.2 mmHg and pulmonary vascular resistance (PVR) of 641.9 ± 374.8 dyne∗s/cm 5 . The peak VO 2 (mean 13.1 ± 4.5 mL∗kg -1 ∗min -1 ) was measured at initial referral. Over a follow-up of up to 10 years (mean 4.41 ± 2.57 years), 31 patients had died. Patients with a baseline peak VO 2  ≥ 10.7 mL∗kg -1 ∗min -1 [area under the receiver-operating characteristic curve (AUC) = 0.728, P = 0.001] had better survival than those with a peak VO 2  ≤ 10.7 mL∗kg -1 ∗min -1 using Kaplan-Meier analysis (88.8% vs 60.1%; log rank P = 0.001). Adjusting for age, gender and PVR, multivariate analysis identified peak VO 2 as a predictor of mortality [hazard ratio (HR): 2.78, 95% CI 1.01-7.63, P = 0.047]. In addition, peak VO 2 failed as an independent prognostic factor in a stepwise multivariate model including all variables significant in the univariate analysis., Conclusions: In patients with inoperable CTEPH the peak VO 2 is a significant predictor of survival, when adjusting for age, gender and PVR. However, peak VO 2 failed as an independent prognostic factor when correcting for all significant baseline variables, which is limiting the clinical usability., (© 2015 John Wiley & Sons Ltd.)

Background: Circulating angiopoietin-1 (Ang-1) has been linked to pulmonary hypertension (PH) in experimental studies. However, the clinical relevance of Ang-1 as a biomarker in PH remains unknown. We aimed to investigate the prognostic and clinical significance of Ang-1 in PH using data from the prospectively recruiting Giessen PH Registry., Methods: Patients with suspected PH (without previous specific pulmonary arterial hypertension [PAH] therapy) who underwent initial right heart catheterization (RHC) in our national referral center between July 2003 and May 2012 and who agreed to optional biomarker analysis were included if they were diagnosed with idiopathic PAH, connective tissue disease-associated PAH (CTD-PAH), PH due to left heart disease (PH-LHD), or chronic thromboembolic PH (CTEPH), or if PH was excluded by RHC (non-PH controls). The association of Ang-1 levels with disease severity (6-minute walk distance and pulmonary hemodynamics) was assessed using linear regression, and the impact of Ang-1 levels on transplant-free survival (primary endpoint) and clinical worsening was assessed using Kaplan-Meier curves, receiver operating characteristic (ROC) analyses, and Cox regression., Results: 151 patients (39, 39, 32, and 41 with idiopathic PAH, CTD-PAH, PH-LHD, and CTEPH, respectively) and 41 non-PH controls were included. Ang-1 levels showed no significant difference between groups (p = 0.8), and no significant associations with disease severity in PH subgroups (p ≥ 0.07). In Kaplan-Meier analyses, Ang-1 levels (stratified by quartile) had no significant impact on transplant-free survival (p ≥ 0.27) or clinical worsening (p ≥ 0.51) in PH subgroups. Regression models found no significant association between Ang-1 levels and outcomes (p ≥ 0.31). ROC analyses found no significant cut-off that would maximize sensitivity and specificity., Conclusions: Despite a strong pathophysiological association in experimental studies, this first comprehensive analysis of Ang-1 in PH subgroups suggests that Ang-1 is not a predictive and clinically relevant biomarker in PH., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Targeted pulmonary vasoactive substances are the cornerstone of treatment in pulmonary arterial hypertension (PAH). Approved drugs act on various receptors and molecules within the pulmonary arteries, mainly causing pulmonary vasodilation and potentially reversing remodeling with consequent improvement of right ventricular function. A key role is attributed to the prostacyclin pathway and especially the prostacyclin receptor (IP). Selexipag is a recently developed, non-prostanoid, oral IP receptor agonist for the treatment of PAH which has been approved in countries/regions including the USA and Europe., Areas Covered: We review the discovery and development of drugs targeting IP receptors in PAH and describe preclinical and phase I studies of selexipag. Furthermore, we review important phase II and III selexipag studies and place them into the clinical context of previously approved prostanoids., Expert Opinion: Oral selexipag offers a promising therapeutic option within the class of available drugs targeting IP receptors. However, its role as first-line therapy based on its efficacy/side-effect profile in current studies is questionable. Most likely, selexipag will be used in combination with other PAH-specific oral drugs. The potential of selexipag to replace or postpone the use of inhaled or parenteral prostanoids needs to be investigated in future trials.

Background: Six-minute walk test (6MWT) is routinely performed in chronic thromboembolic pulmonary hypertension (CTEPH) before pulmonary endarterectomy (PEA). However, the clinical relevance of heart rate response (ΔHR) and exercise-induced oxygen desaturation (EID) during 6MWT is remaining unknown., Methods: Patients undergoing PEA in our center between 03/2013-04/2014 were assessed prospectively with hemodynamic and exercise parameters prior to and 1 year post-PEA. Patients with symptomatic chronic thromboembolic disease (mean pulmonary artery pressure (mPAP) <25 mmHg) and clinical relevant obstructive pulmonary disease were excluded. The following definitions were used: ΔHR = (peak HR - resting HR), percent heart rate reserve (HRR) = (peak HR -rest HR)/(220 - age - rest HR) x 100 and EID = SpO2 ≤88 %., Results: Thirty-seven patients (of 116 patients screened) with mPAP of 43.2 ± 8.7 mmHg, pulmonary vascular resistance (PVR) of 605.5 ± 228.7 dyn*s/cm(5), cardiac index (CI) of 2.4 ± 0.5 l/min/m(2) and a 6MWT-distance of 404.7 ± 148.4 m and a peak VO2 of 12.3 ± 3.4 ml/min/kg prior to PEA were included. Baseline ΔHR during 6MWT was significantly associated with PVR 1 year post-PEA using linear regression analysis (r = 0.43, p = 0.01). Multivariate analysis indicated an association of HRR during 6MWT and residual PH with a hazard ratio of 1.06 (95 % Confidence interval for hazard ratio 0.99-1.14, p = 0.08). EID was observed commonly during 6MWT but no correlations to outcome parameters were found., Conclusions: This is the first prospective study to describe an association of ΔHR during 6MWT with pulmonary hemodynamics 1 year post-PEA. Our preliminary results indicate that HRR derived from 6MWT is of clinical significance. EID was commonly observed, albeit failed as a significant prognostic factor.

Background: Glycosylated hemoglobin A1c (HbA1c) has been proposed as an independent predictor of long-term prognosis in pulmonary arterial hypertension. However, the clinical relevance of HbA1c in patients with operable chronic thromboembolic pulmonary hypertension (CTEPH) remains unknown. The aim of the present study was to investigate the clinical significance of HbA1c as a biomarker in CTEPH., Methods: Prospectively, 102 patients underwent pulmonary endarterectomy (PEA) in our national referral center between March 2013 and March 2014, of which after exclusion 45 patients were analyzed. HbA1c- levels, hemodynamic and exercise parameters were analyzed prior and one-year post-PEA., Results: 45 patients (BMI: 27.3 ± 6.0 kg/m2; age: 62.7 ± 12.3 years) with a mean pulmonary arterial pressure (mPAP) of 43.6 ± 9.4 mmHg, a pulmonary vascular resistance (PVR) of 712.1 ± 520.4 dyn*s/cm5, a cardiac index (CI) of 2.4 ± 0.5 l/min/m2 and a mean HbA1c-level of 39.8 ± 5.6 mmol/mol were included. One-year post-PEA pulmonary hemodynamic and functional status significantly improved in our cohort. Baseline HbA1c-levels were significantly associated with CI, right atrial pressure, peak oxygen uptake and the change of 6-minute walking distance using linear regression analysis. However, using logistic regression analysis baseline HbA1c-levels were not significantly associated with residual post-PEA PH., Conclusions: This is the first prospective study to describe an association of HbA1c-levels with pulmonary hemodynamics and exercise capacity in operable CTEPH patients. Our preliminary results indicate that in these patients impaired glucose metabolism as assessed by HbA1c is of clinical significance. However, HbA1c failed as a predictor of the hemodynamic outcome one-year post-PEA.

Background: Pulmonary endarterectomy (PEA) is the treatment of choice in surgically accessible chronic thromboembolic pulmonary hypertension (CTEPH). An important predictor of outcome is postsurgical residual pulmonary hypertension., Objective: We aimed to use the hemodynamic response during exercise before PEA as a measurement for the hemodynamic outcome 1 year after PEA., Methods: Between January 2011 and December 2013, 299 patients underwent PEA in our center. A total of 16 patients who were assessed by means of invasive hemodynamic measurements during exercise both at baseline and 1 year after PEA were retrospectively analyzed., Results: Pre-PEA mean pulmonary arterial pressure (mPAP) increased during exercise from 35.8 ± 7.6 to 53.8 ± 5.1 mm Hg, diastolic pulmonary arterial pressure (dPAP) from 21.5 ± 5.6 to 30.3 ± 9.6 mm Hg, cardiac output (CO) from 4.4 ± 0.8 to 6.5 ± 1.9 l/min and diastolic pulmonary gradient (DPG) from 14.6 ± 4.9 to 20.7 ± 12.7 mm Hg. Post-PEA mPAP increased from 23.7 ± 6.6 at rest to 43.2 ± 7.1 mm Hg, while CO increased to a higher extent from 5.1 ± 0.9 to 8.4 ± 1.9 l/min. There were significant correlations between pre-PEA DPG/CO and dPAP/CO slopes with the pulmonary vascular resistance (Spearman r = 0.578, p = 0.019, and r = 0.547, p = 0.028) and mPAP at rest after PEA (Spearman r = 0.581, p = 0.018, and r = 0.546, p = 0.028)., Conclusions: In CTEPH, the presurgical dynamic DPG/CO and dPAP/CO slopes during submaximal exercise are associated with the hemodynamic outcome 1 year after PEA.

Background: Patients with pulmonary arterial hypertension (PAH) present with an altered inspiratory capacity (IC) reflecting dynamic hyperinflation (DH) that leads to mechanical constraints and excessive ventilatory demand, particularly during exercise, resulting in exertional dyspnea., Objectives: Assessment of the long-term consequences of altered IC and DH in PAH., Methods: 50 patients with newly diagnosed PAH were prospectively recruited. All patients were assessed by means of right heart catheterization, 6-min walking distance (6MWD) test, lung function and cardiopulmonary exercise testing, including the assessment of IC., Results: 37 patients with idiopathic PAH and 13 patients with conditions associated with PAH (29 female; mean age 51.6 ± 15.1 years; World Health Organization, WHO class, 2.7 ± 0.6) presented with a mean pulmonary arterial pressure of 42.8 ± 15.9 mm Hg and pulmonary vascular resistance (PVR) of 737.2 ± 592.8 dyn*s/cm(5). The mean IC at rest was 87.2 ± 17.3% pred. Kaplan-Meier analysis revealed that patients with an IC at rest >89% pred. had a significantly better 5-year survival than those with lower values (94.1 vs. 75.1%; log-rank p = 0.036). Univariate analysis identified IC at rest (% pred.) as a predictor of survival with a hazard ratio (HR) of 5.05 (95% confidence interval, CI, 0.97-26.24, p = 0.054). In multivariate analysis including PVR, WHO class, 6MWD and peak oxygen uptake as covariates, IC at rest remained an independent predictor of survival (HR: 8.06, 95% CI 0.92-70.34; p = 0.059). DH expressed as ΔIC or static hyperinflation expressed as IC/total lung capacity at rest revealed no prognostic significance., Conclusion: In patients with PAH, IC at rest is of prognostic significance at the time of diagnosis., (© 2014 S. Karger AG, Basel)