Phase 3 Trial of Sotatercept for Treatment of Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension is a progressive disease involving proliferative remodeling of the pulmonary vessels. Despite therapeutic advances, the disease-associated morbidity and mortality remain high. Sotatercept is a fusion protein that traps activins and growth differentiation factors involved in pulmonary arterial hypertension. METHODS: We conducted a multicenter, double-blind, phase 3 trial in which adults with pulmonary arterial hypertension (World Health Organization [WHO] functional class II or III) who were receiving stable background therapy were randomly assigned in a 1:1 ratio to receive subcutaneous sotatercept (starting dose, 0.3 mg per kilogram of body weight; target dose, 0.7 mg per kilogram) or placebo every 3 weeks. The primary end point was the change from baseline at week 24 in the 6-minute walk distance. Nine secondary end points, tested hierarchically in the following order, were multicomponent improvement, change in pulmonary vascular resistance, change in N-terminal pro-B-type natriuretic peptide level, improvement in WHO functional class, time to death or clinical worsening, French risk score, and changes in the Pulmonary Arterial Hypertension-Symptoms and Impact (PAH-SYMPACT) Physical Impacts, Cardiopulmonary Symptoms, and Cognitive/Emotional Impacts domain scores; all were assessed at week 24 except time to death or clinical worsening, which was assessed when the last patient completed the week 24 visit. RESULTS: A total of 163 patients were assigned to receive sotatercept and 160 to receive placebo. The median change from baseline at week 24 in the 6-minute walk distance was 34.4 m (95% confidence interval [CI], 33.0 to 35.5) in the sotatercept group and 1.0 m (95% CI, -0.3 to 3.5) in the placebo group. The Hodges-Lehmann estimate of the difference between the sotatercept and placebo groups in the change from baseline at week 24 in the 6-minute walk distance was 40.8 m (95% CI, 27.5 to 54.1; P<0.001). The first eight secondary end points were significantly improved with sotatercept as compared with placebo, whereas the PAH-SYMPACT Cognitive/Emotional Impacts domain score was not. Adverse events that occurred more frequently with sotatercept than with placebo included epistaxis, dizziness, telangiectasia, increased hemoglobin levels, thrombocytopenia, and increased blood pressure. CONCLUSIONS: In patients with pulmonary arterial hypertension who were receiving stable background therapy, sotatercept resulted in a greater improvement in exercise capacity (as assessed by the 6-minute walk test) than placebo. (Funded by Acceleron Pharma, a subsidiary of MSD; STELLAR ClinicalTrials.gov number, NCT04576988.).

Positive Vasoreactivity Testing in Pulmonary Arterial Hypertension: Therapeutic Consequences, Treatment Patterns, and Outcomes in the Modern Management Era.

BACKGROUND: Among patients with pulmonary arterial hypertension (PAH), acute vasoreactivity testing during right heart catheterization may identify acute vasoresponders, for whom treatment with high-dose calcium channel blockers (CCBs) is recommended. However, long-term outcomes in the current era remain largely unknown. We sought to evaluate the implications of acute vasoreactivity response for long-term response to CCBs and other outcomes. METHODS: Patients diagnosed with PAH between January 1999 and December 2018 at 15 pulmonary hypertension centers were included and analyzed retrospectively. In accordance with current guidelines, acute vasoreactivity response was defined by a decrease of mean pulmonary artery pressure by ≥10 mm Hg to reach <40 mm Hg, without a decrease in cardiac output. Long-term response to CCBs was defined as alive with unchanged initial CCB therapy with or without other initial PAH therapy and World Health Organization functional class I/II and/or low European Society of Cardiology/European Respiratory Society risk status at 12 months after initiation of CCBs. Patients were followed for up to 5 years; clinical measures, outcome, and subsequent treatment patterns were captured. RESULTS: Of 3702 patients undergoing right heart catheterization for PAH diagnosis, 2051 had idiopathic, heritable, or drug-induced PAH, of whom 1904 (92.8%) underwent acute vasoreactivity testing. A total of 162 patients fulfilled acute vasoreactivity response criteria and received an initial CCB alone (n=123) or in combination with another PAH therapy (n=39). The median follow-up time was 60.0 months (interquartile range, 30.8-60.0), during which overall survival was 86.7%. At 12 months, 53.2% remained on CCB monotherapy, 14.7% on initial CCB plus another initial PAH therapy, and the remaining patients had the CCB withdrawn and/or PAH therapy added. CCB long-term response was found in 54.3% of patients. Five-year survival was 98.5% in long-term responders versus 73.0% in nonresponders. In addition to established vasodilator responder criteria, pulmonary artery compliance at acute vasoreactivity testing, low risk status and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels at early follow-up correlated with long-term response and predicted survival. CONCLUSIONS: Our data display heterogeneity within the group of vasoresponders, with a large subset failing to show a sustained satisfactory clinical response to CCBs. This highlights the necessity for comprehensive reassessment during early follow-up. The use of pulmonary artery compliance in addition to current measures may better identify those likely to have a good long-term response.

Tadalafil for Treatment of Combined Postcapillary and Precapillary Pulmonary Hypertension in Patients With Heart Failure and Preserved Ejection Fraction: A Randomized Controlled Phase 3 Study.

BACKGROUND: We assessed the efficacy and safety of tadalafil, a phosphodiesterase type 5 inhibitor, in patients with heart failure with preserved ejection fraction and combined postcapillary and precapillary pulmonary hypertension. METHODS: In the double-blind PASSION study (Phosphodiesterase-5 Inhibition in Patients With Heart Failure With Preserved Ejection Fraction and Combined Post- and Pre-Capillary Pulmonary Hypertension), patients with heart failure with preserved ejection fraction and combined postcapillary and precapillary pulmonary hypertension were randomized 1:1 to receive tadalafil at a target dose of 40 mg or placebo. The primary end point was the time to the first composite event of adjudicated heart failure hospitalization or all-cause death. Secondary end points included all-cause mortality and improvements in New York Heart Association functional class or ≥10% improvement in 6-minute walking distance from baseline. RESULTS: Initially targeting 372 patients, the study was terminated early because of disruption in study medication supply. At that point, 125 patients had been randomized (placebo: 63; tadalafil: 62,). Combined primary end-point events occurred in 20 patients (32%) assigned to placebo and 17 patients (27%) assigned to tadalafil (hazard ratio, 1.02 [95% CI, 0.52-2.01]; P=0.95). There was a possible signal of higher all-cause mortality in the tadalafil group (hazard ratio, 5.10 [95% CI, 1.10-23.69]; P=0.04). No significant between-group differences were observed in other secondary end points. Serious adverse events occurred in 29 participants (48%) in the tadalafil group and 35 (56%) in the placebo group. CONCLUSIONS: The PASSION trial, terminated prematurely due to study medication supply disruption, does not support tadalafil use in patients with heart failure with preserved ejection fraction and combined postcapillary and precapillary pulmonary hypertension, with potential safety concerns and no observed benefits in primary and secondary end points. REGISTRATION: URL: https://www.clinicaltrialsregister.eu/; Unique identifier: 2017-003688-37. URL: https://drks.de; Unique identifier: DRKS -DRKS00014595.

Multilamellated Basement Membranes in the Capillary Network of Alveolar Capillary Dysplasia.

A minimal diffusion barrier is key to the pulmonary gas exchange. In alveolar capillary dysplasia (ACD), a rare genetically driven disease of early infancy, this crucial fibrovascular interface is compromised while the underlying pathophysiology is insufficiently understood. Recent in-depth analyses of vascular alterations in adult lung disease encouraged researchers to extend these studies to ACD and compare the changes of the microvasculature. Lung tissue samples of children with ACD (n = 12), adults with non-specific interstitial pneumonia (n = 12), and controls (n = 20) were studied using transmission electron microscopy, single-gene sequencing, immunostaining, exome sequencing, and broad transcriptome profiling. In ACD, pulmonary capillary basement membranes were hypertrophied, thickened, and multilamellated. Transcriptome profiling revealed increased CDH5, COL4A1, COL15A1, PTK2B, and FN1 and decreased VIT expression, confirmed by immunohistochemistry. In contrast, non-specific interstitial pneumonia samples showed a regular basement membrane architecture with preserved VIT expression but also increased COL15A1+ vessels. This study provides insight into the ultrastructure and pathophysiology of ACD. The lack of normally developed lung capillaries appeared to cause a replacement by COL15A1+ vessels, a mechanism recently described in interstitial lung disease. The VIT loss and FN1 overexpression might contribute to the unique appearance of basement membranes in ACD. Future studies are needed to explore the therapeutic potential of down-regulating the expression of FN1 and balancing VIT deficiency.

Sotatercept for the Treatment of Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension is characterized by pulmonary vascular remodeling, cellular proliferation, and poor long-term outcomes. Dysfunctional bone morphogenetic protein pathway signaling is associated with both hereditary and idiopathic subtypes. Sotatercept, a novel fusion protein, binds activins and growth differentiation factors in the attempt to restore balance between growth-promoting and growth-inhibiting signaling pathways. METHODS: In this 24-week multicenter trial, we randomly assigned 106 adults who were receiving background therapy for pulmonary arterial hypertension to receive subcutaneous sotatercept at a dose of 0.3 mg per kilogram of body weight every 3 weeks or 0.7 mg per kilogram every 3 weeks or placebo. The primary end point was the change from baseline to week 24 in pulmonary vascular resistance. RESULTS: Baseline characteristics were similar among the three groups. The least-squares mean difference between the sotatercept 0.3-mg group and the placebo group in the change from baseline to week 24 in pulmonary vascular resistance was -145.8 dyn · sec · cm-5 (95% confidence interval [CI], -241.0 to -50.6; P = 0.003). The least-squares mean difference between the sotatercept 0.7-mg group and the placebo group was -239.5 dyn · sec · cm-5 (95% CI, -329.3 to -149.7; P<0.001). At 24 weeks, the least-squares mean difference between the sotatercept 0.3-mg group and the placebo group in the change from baseline in 6-minute walk distance was 29.4 m (95% CI, 3.8 to 55.0). The least-squares mean difference between the sotatercept 0.7-mg group and the placebo group was 21.4 m (95% CI, -2.8 to 45.7). Sotatercept was also associated with a decrease in N-terminal pro-B-type natriuretic peptide levels. Thrombocytopenia and an increased hemoglobin level were the most common hematologic adverse events. One patient in the sotatercept 0.7-mg group died from cardiac arrest. CONCLUSIONS: Treatment with sotatercept resulted in a reduction in pulmonary vascular resistance in patients receiving background therapy for pulmonary arterial hypertension. (Funded by Acceleron Pharma; PULSAR ClinicalTrials.gov number, NCT03496207.).

High Prevalence and Clinical Relevance of Intrapulmonary Vascular Dilatations in Patients Undergoing TIPS Implantation.

BACKGROUND & AIMS: Considerate patient selection is vital to ensure the best possible outcomes after transjugular intrahepatic portosystemic shunt (TIPS) insertion. However, data regarding the impact of intrapulmonary vascular dilatations (IPVDs) or hepatopulmonary syndrome (HPS) on the clinical course after TIPS implantation is lacking. Hence, this study aimed to investigate the relevance of IPVD and HPS in patients undergoing TIPS implantation. METHODS: Contrast enhanced echocardiography and blood gas analysis were utilized to determine presence of IPVD and HPS. Multivariable competing risk analyses were performed to evaluate cardiac decompensation (CD), hepatic decompensation (HD), and liver transplant (LTx)-free survival within 1 year of follow-up. RESULTS: Overall, 265 patients were included, of whom 136 had IPVD and 71 fulfilled the HPS criteria. Patients with IPVD had lower Freiburg index of post-TIPS survival (FIPS) scores, lower creatinine, and more often received TIPS because of variceal bleeding. Presence of IPVD was associated with a significantly higher incidence of CD (hazard ratio [HR], 1.756; 95% confidence interval [CI], 1.011-3.048; P = .046) and HD (HR, 1.841; 95% CI, 1.255-2.701; P = .002). However, LTx-free survival was comparable between patients with and without IPVD (HR, 1.081; 95% CI, 0.630-1.855; P = .780). Patients with HPS displayed a trend towards more CD (HR, 1.708; 95% CI, 0.935-3.122; P = .082) and HD (HR, 1.458; 95% CI, 0.934-2.275; P = .097) that failed to reach statistical significance. LTx-free survival did not differ in those with HPS compared with patients without HPS, respectively (HR, 1.052; 95% CI, 0.577-1.921; P = .870). CONCLUSION: Screening for IPVD before TIPS implantation could help to further identify patients at higher risk of CD and HD.

Treatment strategies and survival of patients with connective tissue disease and pulmonary arterial hypertension: a COMPERA analysis.

OBJECTIVES: Pulmonary arterial hypertension (PAH) occurs in various connective tissue diseases (CTDs). We sought to assess contemporary treatment patterns and survival of patients with various forms of CTD-PAH. METHODS: We analysed data from COMPERA, a European pulmonary hypertension registry, to describe treatment strategies and survival in patients with newly diagnosed PAH associated with SSc, SLE, MCTD, UCTD and other types of CTD. All-cause mortality was analysed according to the underlying CTD. For patients with SSc-PAH, we also assessed survival according to initial therapy with endothelin receptor antagonists (ERAs), phosphodiesterase type 5 inhibitors (PDE5is) or a combination of these two drug classes. RESULTS: This analysis included 607 patients with CTD-PAH. Survival estimates at 1, 3 and 5 years for SSc-PAH (n = 390) were 85%, 59% and 42%; for SLE-PAH (n = 34) they were 97%, 77% and 61%; for MCTD-PAH (n = 33) they were 97%, 70% and 59%; for UCTD-PAH (n = 60) they were 88%, 67% and 52%; and for other CTD-PAH (n = 90) they were 92%, 69% and 55%, respectively. After multivariable adjustment, the survival of patients with SSc-PAH was significantly worse compared with the other conditions (P = 0.001). In these patients, the survival estimates were significantly better with initial ERA-PDE5i combination therapy than with initial ERA or PDE5i monotherapy (P = 0.016 and P = 0.012, respectively). CONCLUSIONS: Mortality remains high in patients with CTD-PAH, especially for patients with SSc-PAH. However, for patients with SSc-PAH, our results suggest that long-term survival may be improved with initial ERA-PDE5i combination therapy compared with initial monotherapy.

Feasibility, Repeatability, and Correlation to Lung Function of Phase-Resolved Functional Lung (PREFUL) MRI-derived Pulmonary Artery Pulse Wave Velocity Measurements.

BACKGROUND: Pulse wave velocity (PWV) in the pulmonary arteries (PA) is a marker of vascular stiffening. Currently, only phase-contrast (PC) MRI-based options exist to measure PA-PWV. PURPOSE: To test feasibility, repeatability, and correlation to clinical data of Phase-Resolved Functional Lung (PREFUL) MRI-based calculation of PA-PWV. STUDY TYPE: Retrospective. SUBJECTS: 79 (26 female) healthy subjects (age range 19-78), 58 (24 female) patients with chronic obstructive pulmonary disease (COPD, age range 40-77), 60 (33 female) patients with suspected pulmonary hypertension (PH, age range 28-85). SEQUENCE: 2D spoiled gradient echo, 1.5T. ASSESSMENT: PA-PWV was measured from PREFUL-derived cardiac cycles based on the determination of temporal and spatial distance between lung vasculature voxels using a simplified (sPWV) method and a more comprehensive (cPWV) method including more elaborate distance calculation. For 135 individuals, PC MRI-based PWV (PWV-QA) was measured. STATISTICAL TESTS: Intraclass-correlation-coefficient (ICC) and coefficient of variation (CoV) were used to test repeatability. Nonparametric tests were used to compare cohorts. Correlation of sPWV/cPWV, PWV-QA, forced expiratory volume in 1 sec (FEV1 ) %predicted, residual volume (RV) %predicted, age, and right heart catheterization (RHC) data were tested. Significance level α = 0.05 was used. RESULTS: sPWV and cPWV showed no significant differences between repeated measurements (P-range 0.10-0.92). CoV was generally lower than 15%. COPD and PH patients had significantly higher sPWV and cPWV than healthy subjects. Significant correlation was found between sPWV or cPWV and FEV1 %pred. (R = -0.36 and R = -0.44), but not with RHC (P-range -0.11 - 0.91) or age (P-range 0.23-0.89). Correlation to RV%pred. was significant for cPWV (R = 0.42) but not for sPWV (R = 0.34, P = 0.055). For all cohorts, sPWV and cPWV were significantly correlated with PWV-QA (R = -0.41 and R = 0.48). DATA CONCLUSION: PREFUL-derived PWV is feasible and repeatable. PWV is increased in COPD and PH patients and correlates to airway obstruction and hyperinflation. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

Doppler-derived pulmonary pulse transit time measurements in chronic obstructive pulmonary disease: Reproducibility and cardiopulmonary function.

INTRODUCTION: Doppler-derived pulmonary pulse transit time (pPTT) is an auspicious hemodynamic marker in chronic pulmonary diseases. The aim is to compare four distinct pPTT measurements and its relation to right cardiac and pulmonary function. METHODS: Prospectively, 25 chronic obstructive pulmonary disease (COPD) patients (four patients excluded) and 32 healthy subjects underwent repeated distinct pPTT measurements, standard echocardiography, and pulmonary function testing on the same day. pPTT was defined as the interval from the R or Q-wave in the electrocardiogram to the corresponding pulse wave Doppler peak late systolic (S) 2 or diastolic (D) pulmonary vein flow velocity (pPTT R-S, Q-S, R-D, Q-D). Reproducibility was assessed using Bland-Altman analysis, coefficient of variation (COV), intraclass correlation coefficient (ICC), and power calculations. Associations with right ventricular RV tissue and pulse wave Doppler velocities (RV E', RV S', RV A', RV E, RV A, RV E/E', RV E/A), TAPSE, right ventricular fractional area change, left ventricular systolic and diastolic function (LV ejection fraction, E, A, E/A, E/E', septal E', lateral E'), LA diameters, as well as forced expiratory volume in 1 s, forced vital capacity (FVC) predicted (%), and in liters were analyzed. RESULTS: There was no significant difference and no bias between pPTT measures (p range: .1-.9). COV was in COPD 1.2%-2.3%, in healthy subjects 1.0%-3.1%. ICC ranged from .92 (COPD) to .96 (healthy subjects). In COPD significant correlations were found for pPTT R-S, Q-S and R-D with RV E`, (all > ρ: .49, < p = .0364), pPTT R-S, Q-S with RV E/E` (both > ρ: .49, < p = .0291), pPTT Q-S with RV S´ (ρ: .58, p = .0134), RV A (ρ: .59, p = .0339) and heart rate > ρ: -.39, < p = .0297). pPTT R-S, R-D showed significant correlations with FVC predicted (%) (ρ: .48 p = .0224) and FVC (l) (ρ:.47 p = .0347). CONCLUSIONS: All pPTT measures exhibited high reproducibility. In COPD patients pPTT measures correlate with diastolic right ventricular function. Defining Q as starting point seems clinically advantageous considering electromechanical desynchrony in patients with conduction disorders.

Sotatercept for the treatment of pulmonary arterial hypertension: PULSAR open-label extension.

BACKGROUND: In participants with pulmonary arterial hypertension, 24 weeks of sotatercept resulted in a significantly greater reduction from baseline in pulmonary vascular resistance than placebo. This report characterises the longer-term safety and efficacy of sotatercept in the PULSAR open-label extension. We report cumulative safety, and efficacy at months 18-24, for all participants treated with sotatercept. METHODS: PULSAR was a phase 2, randomised, double-blind, placebo-controlled study followed by an open-label extension, which evaluated sotatercept on top of background pulmonary arterial hypertension therapy in adults. Participants originally randomised to placebo were re-randomised 1:1 to sotatercept 0.3 or 0.7 mg·kg-1 (placebo-crossed group); those initially randomised to sotatercept continued the same sotatercept dose (continued-sotatercept group). Safety was evaluated in all participants who received ≥1 dose of sotatercept. The primary efficacy endpoint was change from baseline to months 18-24 in pulmonary vascular resistance. Secondary endpoints included 6-min walk distance and functional class. Two prespecified analyses, placebo-crossed and delayed-start, evaluated efficacy irrespective of dose. RESULTS: Of 106 participants enrolled in the PULSAR study, 97 continued into the extension period. Serious treatment-emergent adverse events were reported in 32 (30.8%) participants; 10 (9.6%) reported treatment-emergent adverse events leading to study discontinuation. Three (2.9%) participants died, none considered related to study drug. The placebo-crossed group demonstrated significant improvement across primary and secondary endpoints and clinical efficacy was maintained in the continued-sotatercept group. CONCLUSION: These results support the longer-term safety and durability of clinical benefit of sotatercept for pulmonary arterial hypertension.

Effects of sotatercept on haemodynamics and right heart function: analysis of the STELLAR trial.

BACKGROUND: In the phase 3 STELLAR trial, sotatercept, an investigational first-in-class activin signalling inhibitor, demonstrated beneficial effects on 6-min walk distance and additional efficacy endpoints in pre-treated participants with pulmonary arterial hypertension (PAH). METHODS: This post hoc analysis evaluated data from right heart catheterisation (RHC) and echocardiography (ECHO) obtained from the STELLAR trial. Changes from baseline in RHC and ECHO parameters were assessed at 24 weeks. An analysis of covariance (ANCOVA) model was used to estimate differences in least squares means with treatment and randomisation stratification (mono/double versus triple therapy; World Health Organization functional class II versus III) as fixed factors, and baseline value as covariate. RESULTS: Relative to placebo, treatment with sotatercept led to significant (all p<0.0001 except where noted) improvements from baseline in mean pulmonary artery (PA) pressure (-13.9 mmHg), pulmonary vascular resistance (-254.8 dyn·s·cm-5), mean right atrial pressure (-2.7 mmHg), mixed venous oxygen saturation (3.84%), PA elastance (-0.42 mmHg·mL-1·beat-1), PA compliance (0.58 mL·mmHg-1), cardiac efficiency (0.48 mL·beat-1·mmHg-1), right ventricular (RV) work (-0.85 g·m) and RV power (-32.70 mmHg·L·min-1). ECHO showed improvements in tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary artery pressure ratio (0.12 mm·mmHg-1), end-systolic and end-diastolic RV areas (-4.39 cm2 and -5.31 cm2, respectively), tricuspid regurgitation and RV fractional area change (2.04% p<0.050). No significant between-group changes from baseline were seen for TAPSE, heart rate, cardiac output, stroke volume or their indices. CONCLUSION: In pre-treated patients with PAH, sotatercept demonstrated substantial improvements in PA pressures, PA compliance, PA-RV coupling and right heart function.

A Morphomolecular Approach to Alveolar Capillary Dysplasia.

Alveolar capillary dysplasia (ACD) is a rare lung developmental disorder leading to persistent pulmonary arterial hypertension and fatal outcomes in newborns. The current study analyzed the microvascular morphology and the underlying molecular background of ACD. One ACD group (n = 7), one pulmonary arterial hypertension group (n = 20), and one healthy con1trol group (n = 16) were generated. Samples of histologically confirmed ACD were examined by exome sequencing and array-based comparative genomic hybridization. Vascular morphology was analyzed using scanning electron microscopy of microvascular corrosion casts. Gene expression and biological pathways were analyzed using two panels on inflammation/kinase-specific genes and a comparison analysis tool. Compartment-specific protein expression was analyzed using immunostaining. In ACD, there was an altered capillary network, a high prevalence of intussusceptive angiogenesis, and increased activity of C-X-C motif chemokine receptor 4 (CXCR4), hypoxia-inducible factor 1α (HIF1A), and angiopoietin signaling pathways compared with pulmonary arterial hypertension/healthy controls. Histologically, there was a markedly increased prevalence of endothelial tyrosine kinase receptor (TEK/TIE2)+ macrophages in ACD, compared with the other groups, whereas the CXCR4 ligand CXCL12 and HIF1A showed high expression in all groups. ACD is characterized by dysfunctional capillaries and a high prevalence of intussusceptive angiogenesis. The results indicate that endothelial CXCR4, HIF1A, and angiopoietin signaling as well as TIE2+ macrophages are crucial for the induction of intussusceptive angiogenesis and vascular remodeling. Future studies should address the use of anti-angiogenic agents in ACD, where TIE2 appears as a promising target.

Multicenter Standardization of Phase-Resolved Functional Lung MRI in Patients With Suspected Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: Detection of pulmonary perfusion defects is the recommended approach for diagnosing chronic thromboembolic pulmonary hypertension (CTEPH). This is currently achieved in a clinical setting using scintigraphy. Phase-resolved functional lung (PREFUL) magnetic resonance imaging (MRI) is an alternative technique for evaluating regional ventilation and perfusion without the use of ionizing radiation or contrast media. PURPOSE: To assess the feasibility and image quality of PREFUL-MRI in a multicenter setting in suspected CTEPH. STUDY TYPE: This is a prospective cohort sub-study. POPULATION: Forty-five patients (64 ± 16 years old) with suspected CTEPH from nine study centers. FIELD STRENGTH/SEQUENCE: 1.5 T and 3 T/2D spoiled gradient echo/bSSFP/T2 HASTE/3D MR angiography (TWIST). ASSESSMENT: Lung signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared between study centers with different MRI machines. The contrast between normally and poorly perfused lung areas was examined on PREFUL images. The perfusion defect percentage calculated using PREFUL-MRI (QDPPREFUL ) was compared to QDP from the established dynamic contrast-enhanced MRI technique (QDPDCE ). Furthermore, QDPPREFUL was compared between a patient subgroup with confirmed CTEPH or chronic thromboembolic disease (CTED) to other clinical subgroups. STATISTICAL TESTS: t-Test, one-way analysis of variance (ANOVA), Pearson's correlation. Significance level was 5%. RESULTS: Significant differences in lung SNR and CNR were present between study centers. However, PREFUL perfusion images showed a significant contrast between normally and poorly perfused lung areas (mean delta of normalized perfusion -4.2% SD 3.3) with no differences between study sites (ANOVA: P = 0.065). QDPPREFUL was significantly correlated with QDPDCE (r = 0.66), and was significantly higher in 18 patients with confirmed CTEPH or CTED (57.9 ± 12.2%) compared to subgroups with other causes of PH or with excluded PH (in total 27 patients with mean ± SD QDPPREFUL = 33.9 ± 17.2%). DATA CONCLUSION: PREFUL-MRI could be considered as a non-invasive method for imaging regional lung perfusion in multicenter studies. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 1.

COMPERA 2.0: a refined four-stratum risk assessment model for pulmonary arterial hypertension.

BACKGROUND: Risk stratification plays an essential role in the management of patients with pulmonary arterial hypertension (PAH). The current European guidelines propose a three-stratum model to categorise risk as low, intermediate or high, based on the expected 1-year mortality. However, with this model, most patients are categorised as intermediate risk. We investigated a modified approach based on four risk categories, with intermediate risk subdivided into intermediate-low and intermediate-high risk. METHODS: We analysed data from the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA), a European pulmonary hypertension registry, and calculated risk at diagnosis and first follow-up based on World Health Organization functional class, 6-min walk distance (6MWD) and serum levels of brain natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP), using refined cut-off values. Survival was assessed using Kaplan-Meier analyses, log-rank testing and Cox proportional hazards models. RESULTS: Data from 1655 patients with PAH were analysed. Using the three-stratum model, most patients were classified as intermediate risk (76.0% at baseline and 63.9% at first follow-up). The refined four-stratum risk model yielded a more nuanced separation and predicted long-term survival, especially at follow-up assessment. Changes in risk from baseline to follow-up were observed in 31.1% of the patients with the three-stratum model and in 49.2% with the four-stratum model. These changes, including those between the intermediate-low and intermediate-high strata, were associated with changes in long-term mortality risk. CONCLUSIONS: Modified risk stratification using a four-stratum model based on refined cut-off levels for functional class, 6MWD and BNP/NT-proBNP was more sensitive to prognostically relevant changes in risk than the original three-stratum model.

Temporal trends in pulmonary arterial hypertension: results from the COMPERA registry.

BACKGROUND: Since 2015, the European pulmonary hypertension guidelines recommend the use of combination therapy in most patients with pulmonary arterial hypertension (PAH). However, it is unclear to what extent this treatment strategy is adopted in clinical practice and if it is associated with improved long-term survival. METHODS: We analysed data from COMPERA, a large European pulmonary hypertension registry, to assess temporal trends in the use of combination therapy and survival of patients with newly diagnosed PAH between 2010 and 2019. For survival analyses, we looked at annualised data and at cumulated data comparing the periods 2010-2014 and 2015-2019. RESULTS: A total of 2531 patients were included. The use of early combination therapy (within 3 months after diagnosis) increased from 10.0% in patients diagnosed with PAH in 2010 to 25.0% in patients diagnosed with PAH in 2019. The proportion of patients receiving combination therapy 1 year after diagnosis increased from 27.7% to 46.3%. When comparing the 2010-2014 and 2015-2019 periods, 1-year survival estimates were similar (89.0% (95% CI 87.2-90.9%) and 90.8% (95% CI 89.3-92.4%), respectively), whereas there was a slight but nonsignificant improvement in 3-year survival estimates (67.8% (95% CI 65.0-70.8%) and 70.5% (95% CI 67.8-73.4%), respectively). CONCLUSIONS: The use of combination therapy increased from 2010 to 2019, but most patients still received monotherapy. Survival rates at 1 year after diagnosis did not change over time. Future studies need to determine if the observed trend suggesting improved 3-year survival rates can be confirmed.

Gene panel diagnostics reveals new pathogenic variants in pulmonary arterial hypertension.

BACKGROUND: A genetic predisposition can lead to the rare disease pulmonary arterial hypertension (PAH). Most mutations have been identified in the gene BMPR2 in heritable PAH. However, as of today 15 further PAH genes have been described. The exact prevalence across these genes particularly in other PAH forms remains uncertain. We present the distribution of mutations across PAH genes identified at the largest German referral centre for genetic diagnostics in PAH over a course of > 3 years. METHODS: Our PAH-specific gene diagnostics panel was used to sequence 325 consecutive PAH patients from March 2017 to October 2020. For the first year the panel contained thirteen PAH genes: ACVRL1, BMPR1B, BMPR2, CAV1, EIF2AK4, ENG, GDF2, KCNA5, KCNK3, KLF2, SMAD4, SMAD9 and TBX4. These were extended by the three genes ATP13A3, AQP1 and SOX17 from March 2018 onwards following the genes' discovery. RESULTS: A total of 79 mutations were identified in 74 patients (23%). Of the variants 51 (65%) were located in the gene BMPR2 while the other 28 variants were found in ten further PAH genes. We identified disease-causing variants in the genes AQP1, KCNK3 and SOX17 in families with at least two PAH patients. Mutations were not only detected in patients with heritable and idiopathic but also with associated PAH. CONCLUSIONS: Genetic defects were identified in 23% of the patients in a total of 11 PAH genes. This illustrates the benefit of the specific gene panel containing all known PAH genes.

Periprocedural safety and outcome after pump implantation for intravenous treprostinil administration in patients with pulmonary arterial hypertension.

METHODS: In this retrospective observational study, we analyzed all patients with pulmonary arterial hypertension undergoing LenusPro® pump implantation between November 2013 and October 2019 at our center. Periprocedural safety was assessed by describing all complications that occurred within 28 days after surgery; complications that occurred later were described to assess long-term safety. Clinical outcomes were measured by comparison of clinical parameters and echocardiographic measurements of right ventricular function from baseline to 6-months-follow-up. RESULTS: Fifty-four patients underwent LenusPro® pump implantation for intravenous treprostinil treatment during the investigation period. Periprocedural complications occurred in 5 patients; the only anesthesia-related complication (right heart failure with recovery after prolonged intensive care and death in the further course) occurred in the only patient who underwent general anesthesia. All other patients underwent local anesthesia with or without short-acting (analgo-) sedation. Eighteen long-term complications occurred in 15 patients, most notably pump pocket or catheter related problems. Transplant-free survival rates at 1, 2, and 3 years were 77 %, 56 %, and 48 %, respectively. CONCLUSIONS: Subcutaneous pump implantation under local anesthesia and conscious analgosedation while avoiding intubation and mechanical ventilation is feasible in patients with advanced PAH. Controlled studies are needed to determine the safest anesthetic approach for this procedure. BACKGROUND/OBJECTIVES: Intravenous treprostinil treatment via a fully implantable pump is a treatment option for patients with advanced pulmonary arterial hypertension. However, there is no consensus on the preferred anesthetic approach for the implantation procedure. Primary objective was to assess periprocedural safety with particular attention to feasibility of local anesthesia and conscious analgosedation instead of general anesthesia. Long-term safety and clinical outcomes were secondary endpoints.

Chronic Thromboembolic Pulmonary Hypertension Perioperative Monitoring Using Phase-Resolved Functional Lung (PREFUL)-MRI.

BACKGROUND: The translation of phase-resolved functional lung (PREFUL)-MRI to routine practice in monitoring chronic thromboembolic pulmonary hypertension (CTEPH) still requires clinical corresponding imaging biomarkers of pulmonary vascular disease. PURPOSE: To evaluate successful pulmonary endarterectomy (PEA) via PREFUL-MRI with pulmonary pulse wave transit time (pPTT). STUDY TYPE: Retrospective. POPULATION: Thirty CTEPH patients and 12 healthy controls were included. FIELD STRENGTH/SEQUENCE: For PREFUL-MRI a 2D spoiled gradient echo sequence and for DCE-MRI a 3D time-resolved angiography with stochastic trajectories (TWIST) sequence were performed on 1.5T. ASSESSMENT: Eight coronal slices of PREFUL-MRI were obtained on consecutive 13 days before and 14 days after PEA. PREFUL quantitative lung perfusion (PREFULQ ) phases over the whole cardiac cycle were calculated to quantify pPTT, the time the pulmonary pulse wave travels from the central pulmonary arteries to the pulmonary capillaries. Also, perfusion defect percentage based on pPTT (QDPpPTT ), PREFULQ (QDPPREFUL ), and V/Q match were calculated. For DCE-MRI, pulmonary blood flow (PBF) and QDPPBF were computed as reference. For clinical correlation, mean pulmonary arterial pressure (mPAP) and 6-minute walking distance were evaluated preoperatively and after PEA. STATISTICAL TESTS: The Shapiro-Wilk test, paired two-sided Wilcoxon rank sum test, Dice coefficient, and Spearman's correlation coefficient (ρ) were applied. RESULTS: Median pPTT was significantly lower post PEA (139 msec) compared to pre PEA (193 msec), P = 0.0002. Median pPTT correlated significantly with the mPAP post PEA (r = 0.52, P < 0.008). Median pPTT was distributed more homogeneously after PEA: IQR pPTT decreased from 336 to 281 msec (P < 0.004). Median PREFULQ (P < 0.0002), QDPpPTT (P < 0.0478), QDPPREFUL (P < 0.0001) and V/Q match (P < 0.0001) improved significantly after PEA. Percentage change of PREFULQ correlated significantly with percentage change of 6-minute walking distance (ρ = 0.61; P = 0.0031) 5 months post PEA. DATA CONCLUSION: Perioperative perfusion changes in CTEPH can be detected and quantified by PREFUL-MRI. Normalization of pPTT reflects surgical success and improvement of PREFULQ predicts 6-minute walking distance changes. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:610-619.

Pulmonary hypertension in chronic lung disease and hypoxia.

Pulmonary hypertension (PH) frequently complicates the course of patients with various forms of chronic lung disease (CLD). CLD-associated PH (CLD-PH) is invariably associated with reduced functional ability, impaired quality of life, greater oxygen requirements and an increased risk of mortality. The aetiology of CLD-PH is complex and multifactorial, with differences in the pathogenic sequelae between the diverse forms of CLD. Haemodynamic evaluation of PH severity should be contextualised within the extent of the underlying lung disease, which is best gauged through a combination of physiological and imaging assessment. Who, when, if and how to screen for PH will be addressed in this article, as will the current state of knowledge with regard to the role of treatment with pulmonary vasoactive agents. Although such therapy cannot be endorsed given the current state of findings, future studies in this area are strongly encouraged.