Search

Abstract A simplified 4‐strata risk stratification approach based on three variables is widespread in pulmonary arterial hypertension (PAH) at follow‐up. This study aimed to assess the impact of replacing the 6‐min walk test (6MWT) with the peak 02 uptake evaluated by the cardiopulmonary exercise test (CPET) on risk stratification by this scale. We included 180 prevalent patients with PAH from two reference hospitals in Spain, followed up between 2006 and 2022. Patients were included if all the variables of interest were available within a 3‐month period on the Spanish Registry of Pulmonary Arterial Hypertension (REHAP): functional class (FC); NT‐proBNP; 6MWT; and CPET. The original 4‐strata model (NT‐proBNP, 6MWT, FC) identified most patients at low or intermediate‐low risk (36.7% and 51.1%, respectively). Notably, the modified scale (NT‐proBNP, CPET, FC) improved the identification of patients at intermediate‐high risk up to 18.9%, and at high risk up to 1.1% in comparison with the previous 12.2% and 0.0% in the original scale. This new model increased the number of patients correctly classified into higher‐risk strata (positive NRI of 0.06), as well as classified more patients without events in lower‐risk strata (negative NRI of 0.04). The proposed score showed a slightly superior prognostic capacity compared with the original model (Harrel's C‐index 0.717 vs. 0.709). Using O2 uptake instead of distance walked in the 6MWT improves the identification of high‐risk patients using the 4‐strata scale. This change could have relevant prognostic implications and lead to changes in the specific treatment of PAH.

Preclinical and early clinical studies suggest that angiotensin-converting enzyme type 2 activity may be impaired in patients with pulmonary arterial hypertension (PAH); therefore, administration of exogenous angiotensin-converting enzyme type 2 (ACE2) may be beneficial. This Phase IIa, multi-center, open-label, exploratory, single-dose, dose-escalation study (NCT03177603) assessed the potential vasodilatory effects of single doses of GSK2586881 (a recombinant human ACE2) on acute cardiopulmonary hemodynamics in hemodynamically stable adults with documented PAH who were receiving background PAH therapy. Successive cohorts of participants were administered a single intravenous dose of GSK2586881 of 0.1, 0.2, 0.4, or 0.8 mg/kg. Dose escalation occurred after four or more participants per cohort were dosed and a review of safety, tolerability, pharmacokinetics, and hemodynamic data up to 24 h postdose was undertaken. The primary endpoint was a change in cardiopulmonary hemodynamics (pulmonary vascular resistance, cardiac index, and mean pulmonary artery pressure) from baseline. Secondary/exploratory objectives included safety and tolerability, effect on renin-angiotensin system peptides, and pharmacokinetics. GSK2586881 demonstrated no consistent or sustained effect on acute cardiopulmonary hemodynamics in participants with PAH receiving background PAH therapy (N = 23). All doses of GSK2586881 were well tolerated. GSK2586881 was quantifiable in plasma for up to 4 h poststart of infusion in all participants and caused a consistent and sustained reduction in angiotensin II and a corresponding increase in angiotensin (1-7) and angiotensin (1-5). While there does not appear to be a consistent acute vasodilatory response to single doses of GSK2586881 in participants with PAH, the potential benefits in terms of chronic vascular remodeling remain to be determined.

Abstract The coronavirus 2019 disease (COVID‐19) pandemic threatened the Spanish health‐care system. Patients with demanding conditions such as precapillary pulmonary hypertension (PH) faced a potentially severe infection, while their usual access to medical care was restricted. This prospective, unicentric study assessed the impact of COVID‐19 on PH patients' outcomes and the operational changes in the PH network. Sixty‐three PH patients (41 pulmonary arterial hypertension [PAH]; 22 chronic thromboembolic pulmonary hypertension [CTEPH]) experienced COVID‐19. Overall mortality was 9.5% without differences when stratifying by hemodynamics or PAH‐risk score. Patients who died were older (73.6 ± 5 vs. 52.2 ± 15.4; p = 0.001), with more comorbidities (higher Charlson index: 4.17 ± 2.48 vs. 1.14 ± 1.67; p = 0.0002). Referrals to the PH expert center decreased compared to the previous 3 years (123 vs. 160; p = 0.002). The outpatient activity shifted toward greater use of telemedicine. Balloon pulmonary angioplasty activity could be maintained after the first pandemic wave and lockdown while pulmonary thromboendarterectomy procedures decreased (19 vs. 36; p = 0.017). Pulmonary transplantation activity remained similar. The COVID‐19 mortality in PAH/CTEPH patients was not related to hemodynamic severity or risk stratification, but to comorbidities. The pandemic imposed structural changes but a planned organization and resource reallocation made it possible to maintain PH patients' care.

BackgroundAdvanced age, frailty, and age-related comorbidities are the major causes of pulmonary endarterectomy disqualification in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Balloon pulmonary angioplasty (BPA) is an attractive and less invasive therapy for elderly patients. However, information about the safety, procedure tolerance, and effectiveness of BPA in elderly patients is limited.Objective and methodsWe aimed to analyze the safety, tolerance, and efficacy of BPA in CTEPH patients aged ≥70 years. This observational, descriptive, and retrospective series included consecutive patients aged ≥70 years, who underwent completed or interrupted BPA programs at a pulmonary hypertension reference center between May 2013 and May 2022.ResultsWe enrolled 155 patients in our institution's BPA program. Among these, 33 patients were aged ≥70 years (mean age, 76.4 years; women, 75.8%) and had finished or interrupted BPA programs. In this cohort, we performed 116 BPA procedures (average, 3.6 ± 1.8 sessions/patient). Among the 33 patients, 19 (57.6%) completed treatment for all lobes, while the BPA program was interrupted in the remaining 14 (42.4%). Among all 33 patients, BPA was associated with a significant reduction in mean pulmonary arterial pressure (39.2 ± 9.3 vs. 32.8 ± 8.8 mmHg; p < 0.001) and pulmonary vascular resistance (6.7 ± 3.1 vs. 4.4 ± 2.0 WU; p < 0.001), along with an improvement in the cardiac index (2.5 ± 0.6 vs. 2.8 ± 0.7 L/min/m2; p = 0.04) with significant reductions in the N-terminal prohormone of brain natriuretic peptide level (pre-BPA, 353 pg/mL [207–1,960 pg/mL] vs. post-BPA, 167 pg/mL [73–629 pg/mL]; p = 0.03). The patients' functional class improved, and pulmonary hypertension-targeting drug requirements were significantly reduced. The pulmonary injury appeared in 3.4% of the 116 procedures, of which 50% were of grade 2. No patient of ≥70 years had grade 5 pulmonary injury. One periprocedural mortality was recorded (3%), and the median follow-up period was 2.8 years. The survival rate of the entire cohort at 1 and 3 years was 90.5 and 82.8%, respectively.ConclusionBPA is an effective and safe approach in patients aged ≥70 years. It significantly improves patients' functional class, hemodynamic, and biomarkers, and reduces their pulmonary hypertension-targeting medical therapy requirements. These successes were achieved even though a significant percentage of patients did not complete the therapy. The rates of procedural complications and periprocedural mortality were low. Survival at 1 and 3 years was good in comparison to that of younger patients undergoing BPA.

Abstract Background During the COVID-19 pandemic, most of the health care systems suspended their non-urgent activities. This included the cancellation of consultations for patients with rare diseases, such as severe pulmonary hypertension (PH), resulting in potential medication shortage and loss of follow-up. Thus, the aim of the study was to evaluate PH patient health status evolution, access to health care and mental health experience during the early phase of the pandemic. Methods We conducted an online patient survey, available in 16 languages, between 22/05/2020 and 28/06/2020. The survey included questions corresponding to demographic, COVID-19 and PH related information. Results 1073 patients (or relatives, 27%) from 52 countries all over the world participated in the survey. Seventy-seven percent (77%) of responders reported a diagnosis of pulmonary arterial hypertension and 15% of chronic thromboembolic PH. The COVID-19 related events were few: only 1% of all responders reported a diagnosis of COVID-19. However, 8% of patients reported health deterioration possibly related to PH, and 4% hospitalization for PH. Besides, 11% of the patients reported difficulties to access their PH expert centre, and 3% interruption of treatment due to shortage of medication. Anxiety or depression was reported by 67% of the participants. Conclusion Although COVID-19 incidence in PH patients was low, PH related problems occurred frequently as the pandemic progressed, including difficulties to have access to specialized care. The importance of primary health care was emphasized. Further studies are needed to evaluate the long-term consequences of COVID-related PH care disruption.

Pulmonary arterial hypertension (PAH) is a severe condition with a high mortality rate despite advances in diagnostic and therapeutic strategies. In recent years, significant scientific progress has been made in the understanding of the underlying pathobiological mechanisms. Since current available treatments mainly target pulmonary vasodilation, but lack an effect on the pathological changes that develop in the pulmonary vasculature, there is need to develop novel therapeutic compounds aimed at antagonizing the pulmonary vascular remodeling. This review presents the main molecular mechanisms involved in the pathobiology of PAH, discusses the new molecular compounds currently being developed for the medical treatment of PAH and assesses their potential future role in the therapeutic algorithms of PAH.

(1) Background: Pulmonary endarterectomy (PEA) is the “gold standard” treatment for operable patients with chronic thromboembolic pulmonary hypertension (CTEPH). Persistent pulmonary hypertension (PH) after PEA confers a worse prognosis. Balloon pulmonary angioplasty (BPA) could represent a useful therapy in this setting, but evidence about its effectiveness and safety in patients with previous PEA is limited. (2) Methods: A total of 14 patients with persistent PH after PEA were treated with BPA in a single PH center. Hemodynamic and clinical effects of BPA and complications of the procedure were retrospectively collected. (3) Results: After BPA, the mean pulmonary arterial pressure fell from 50.7 ± 15.3 mmHg to 38.0 ± 7.9 mmHg (25.0% decrease; 95% confidence interval (CI) 14.0–35.5%; p = 0.01). Pulmonary vascular resistances were reduced from 8.5 ± 3.6 WU to 5.3 ± 2.2 WU (37.6% decrease; 95% CI 18.8–56.5%; p = 0.01). WHO functional class was also improved with BPA. Severe BPA-related complications were infrequent and no periprocedural deaths were observed. (4) Conclusions: BPA is an effective and safe therapy for patients with CTEPH and persistent PH after PEA.

Abstract Preclinical and early clinical studies suggest that angiotensin‐converting enzyme type 2 activity may be impaired in patients with pulmonary arterial hypertension (PAH); therefore, administration of exogenous angiotensin‐converting enzyme type 2 (ACE2) may be beneficial. This Phase IIa, multi‐center, open‐label, exploratory, single‐dose, dose‐escalation study (NCT03177603) assessed the potential vasodilatory effects of single doses of GSK2586881 (a recombinant human ACE2) on acute cardiopulmonary hemodynamics in hemodynamically stable adults with documented PAH who were receiving background PAH therapy. Successive cohorts of participants were administered a single intravenous dose of GSK2586881 of 0.1, 0.2, 0.4, or 0.8 mg/kg. Dose escalation occurred after four or more participants per cohort were dosed and a review of safety, tolerability, pharmacokinetics, and hemodynamic data up to 24 h postdose was undertaken. The primary endpoint was a change in cardiopulmonary hemodynamics (pulmonary vascular resistance, cardiac index, and mean pulmonary artery pressure) from baseline. Secondary/exploratory objectives included safety and tolerability, effect on renin‐angiotensin system peptides, and pharmacokinetics. GSK2586881 demonstrated no consistent or sustained effect on acute cardiopulmonary hemodynamics in participants with PAH receiving background PAH therapy (N = 23). All doses of GSK2586881 were well tolerated. GSK2586881 was quantifiable in plasma for up to 4 h poststart of infusion in all participants and caused a consistent and sustained reduction in angiotensin II and a corresponding increase in angiotensin (1–7) and angiotensin (1–5). While there does not appear to be a consistent acute vasodilatory response to single doses of GSK2586881 in participants with PAH, the potential benefits in terms of chronic vascular remodeling remain to be determined.

Abstract Background Macitentan is a dual endothelin receptor antagonist indicated for the long-term treatment of pulmonary arterial hypertension (PAH). We evaluated the change over time in REVEAL risk score in incident and prevalent patients receiving macitentan for the first time. Methods Retrospective, observational study including adult patients with idiopathic/heritable PAH or PAH associated with connective tissue disorders or congenital heart disease treated with macitentan for ≥6-month follow-up in Spain. The REVEAL risk score and risk strata were computed at the start of macitentan and after ≥6-month in patients with ≥7 out of 12 valid REVEAL components. Results Overall, 81 patients (57 for the REVEAL score) were analysed, 77.8% women. The mean age was 57.2 years and 50.6% of patients had idiopathic/heritable PAH. Prevalent patients were 59.3 and 40.7% were incident. Main therapies for PAH included macitentan monotherapy (42.0%) and macitentan in combination with phosphodiesterase type 5 inhibitor (44.4%). With a median time of macitentan treatment of 10.5 months, the mean REVEAL score was 8.7 points at baseline and was 7.2 points after ≥6-month follow-up. The mean change (95% CI) in REVEAL risk score was − 1.4 (− 2.0, − 0.9) points (p

Abstract Background There is little information about vitamin D (Vit D) deficiency in patients with pulmonary hypertension (PH). The objective of this study was: 1) compare Vit D levels between patients with PH, left ventricular failure (LVF) and healthy subjects (HS); 2) correlate, in patients with PH, Vit D levels with prognosis-related variables, such as the 6-min walk test (6MWT). Methods Vitamin D levels were measured in a cross-sectional study in 126 patients from one of three groups: patients with PH (n = 53), patients with LVF (n = 42) and healthy subjects (n = 31). In all groups, 8-h fasting blood samples were obtained in the morning. In the PH and the LVF group, functional class (WHO criteria), metres covered in the 6MWT and echocardiographic parameters were analysed. In the PH group, plasma N terminal pro B type natriuretic peptide (NT-proBNP) level was analysed and a complete haemodynamic evaluation by right heart catheterisation was made. Results Mean Vit D levels were lower in PH than in both other groups (ng/ml, mean ± SD): PH 19.25 ± 10, LVF 25.68 ± 12, HS 28.8 ± 12 (PH vs LVF p = 0.017, PH vs HS p = 0.001 and HS vs LVF p = 0.46). Vit D deficiency prevalence was higher in PH as compared to the other groups (PH 53.8%, LVF 45.2%, HS 25%, p = 0.01). Patients with PH in functional class (FC; WHO criteria) III–IV had higher Vit D deficiency prevalence than those in FC I–II (86.7% vs 40.5%, p = 0.003). There was a significant linear correlation between the 6MWT and Vit D levels in PH (p

Background: Pulmonary arterial hypertension (PAH) is a severe and rare disease with an important genetic background. The influence of genetic testing in the clinical classification of pediatric PAH is not well known and genetics could influence management and prognosis. Objectives: The aim of this work was to identify the molecular fingerprint of PH children in the REgistro de pacientes con HIpertensión Pulmonar PEDiátrica (REHIPED), and to investigate if genetics could have an impact in clinical reclassification and prognosis. Methods: We included pediatric patients with a genetic analysis from REHIPED. From 2011 onward, successive genetic techniques have been carried out. Before genetic diagnosis, patients were classified according to their clinical and hemodynamic data in five groups. After genetic analysis, the patients were reclassified. The impact of genetics in survival free of lung transplantation was estimated by Kaplan–Meier curves. Results: Ninety-eight patients were included for the analysis. Before the genetic diagnoses, there were idiopathic PAH forms in 53.1%, PAH associated with congenital heart disease in 30.6%, pulmonary veno-occlusive disease—PVOD—in 6.1%, familial PAH in 5.1%, and associated forms with multisystemic disorders—MSD—in 5.1% of the patients. Pathogenic or likely pathogenic variants were found in 44 patients (44.9%). After a genetic analysis, 28.6% of the cohort was “reclassified”, with the groups of heritable PAH, heritable PVOD, TBX4, and MSD increasing up to 18.4%, 8.2%, 4.1%, and 12.2%, respectively. The MSD forms had the worst survival rates, followed by PVOD. Conclusions: Genetic testing changed the clinical classification of a significant proportion of patients. This reclassification showed relevant prognostic implications.

Pulmonary arterial hypertension (PAH) is a severe clinical condition characterized by an increase in mean pulmonary artery pressure, which leads to a right ventricular hypertrophy and potentially heart failure and death. In the last several years, many genes have been associated with PAH, particularly in idiopathic and heritable forms but also in associated forms. Here we described the identification of two unrelated families in which the AQP1 variant was found from a cohort of 300 patients. The variants were identified by whole exome sequencing (WES). In the first family, the variant was detected in three affected members from a hereditary PAH, and in the second family the proband had PAH associated with scleroderma. In addition, we have reviewed all cases published in the literature thus far of patients with PAH and AQP1 variants. Functional studies have led to some contradictory conclusions, and the evidence of the relationship of AQP1 and PAH is still limited. However, we describe two further families with PAH and variants in AQP1, expanding both the number of cases and the clinically associated phenotype. We provide further evidence of the association of AQP1 and the development of hereditary and associated forms of PAH.

Background The determinants and consequences of pulmonary hypertension after successfully corrected valvular heart disease remain poorly understood. We aim to clarify the hemodynamic bases and risk factors for mortality in patients with this condition. Methods and Results We analyzed long‐term follow‐up data of 222 patients with pulmonary hypertension and valvular heart disease successfully corrected at least 1 year before enrollment who had undergone comprehensive hemodynamic and imaging characterization as per the SIOVAC (Sildenafil for Improving Outcomes After Valvular Correction) clinical trial. Median (interquartile range) mean pulmonary pressure was 37 mm Hg (32–44 mm Hg) and pulmonary artery wedge pressure was 23 mm Hg (18–26 mm Hg). Most patients were classified either as having combined precapillary and postcapillary or isolated postcapillary pulmonary hypertension. After a median follow‐up of 4.5 years, 91 deaths accounted for 4.21 higher‐than‐expected mortality in the age‐matched population. Risk factors for mortality were male sex, older age, diabetes mellitus, World Health Organization functional class III and higher pulmonary vascular resistance—either measured by catheterization or approximated from ultrasound data. Higher pulmonary vascular resistance was related to diabetes mellitus and smaller residual aortic and mitral valve areas. In turn, the latter correlated with prosthetic nominal size. Six‐month changes in the composite clinical score and in the 6‐minute walk test distance were related to survival. Conclusions Persistent valvular heart disease–pulmonary hypertension is an ominous disease that is almost universally associated with elevated pulmonary artery wedge pressure. Pulmonary vascular resistance is a major determinant of mortality in this condition and is related to diabetes mellitus and the residual effective area of the corrected valve. These findings have important implications for individualizing valve correction procedures. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00862043.

BACKGROUND:The knowledge of hereditary predisposition has changed our understanding of Pulmonary Arterial Hypertension. Genetic testing has been widely extended and the application of Pulmonary Arterial Hypertension specific gene panels has allowed its inclusion in the diagnostic workup and increase the diagnostic ratio compared to the traditional sequencing techniques. This is particularly important in the differential diagnosis between Pulmonary Arterial Hypertension and Pulmonary Venoocclusive Disease. METHODS:Since November 2011, genetic testing is offered to all patients with idiopathic, hereditable and associated forms of Pulmonary Arterial Hypertension or Pulmonary Venoocclusive Disease included in the Spanish Registry of Pulmonary Arterial Hypertension. Herein, we present the clinical phenotype and prognosis of all Pulmonary Arterial Hypertension patients with disease-associated variants in TBX4. RESULTS:Out of 579 adults and 45 children, we found in eight patients from seven families, disease-causing associated variants in TBX4. All adult patients had a moderate-severe reduction in diffusion capacity. However, we observed a wide spectrum of clinical presentations, including Pulmonary Venoocclusive Disease suspicion, interstitial lung disease, pulmonary vascular abnormalities and congenital heart disease. CONCLUSIONS:Genetic testing is now essential for a correct diagnosis work-up in Pulmonary Arterial Hypertension. TBX4-associated Pulmonary Arterial Hypertension has marked clinical heterogeneity. In this regard, a genetic study is extremely useful to obtain an accurate diagnosis and provide appropriate management.

Pulmonary arterial hypertension (PAH) sometimes co-exists with hereditary hemorrhagic telangiectasia (HHT). Despite being clinically diagnosable according to Curaçao criteria, HHT can be difficult to diagnose due to its clinically heterogenicity and highly overlapping with PAH. Genetic analysis of the associated genes ACVRL1, ENG, SMAD4 and GDF2 can help to confirm or discard the presumptive diagnosis. As part of the clinical routine and to establish a genetic diagnosis, we have analyzed a cohort of patients with PAH and overlapping HHT features through a customized Next Generation Sequencing (NGS) panel of 21 genes, designed and validated in-house. We detected a homozygous missense variant in GDF2 in a pediatric patient diagnosed with PAH associated with HHT and a missense variant along with a heterozygous deletion in another idiopathic PAH patient (compound heterozygous inheritance). In order to establish variant segregation, we analyzed all available family members. In both cases, parents were carriers for the variants, but neither was affected. Our results expand the clinical spectrum and the inheritance pattern associated with GDF2 pathogenic variants suggesting incomplete penetrance and/or variability of expressivity with a semi-dominant pattern of inheritance.

(1) Background: Clinical presentation, disease distribution, or treatment received may provide insights into the reasons contributing to sex differences in chronic thromboembolic pulmonary hypertension (CTEPH). (2) Methods: We evaluated 453 patients (56% women) between 2007–2019. Data was collected from REHAP (Registro Español de Hipertensión Arterial Pulmonar) registry. Two time periods were selected to evaluate the influence of new treatments over time. (3) Results: Women were older. Baseline functional class was worse, and distance walked shorter in women compared with men. Women had higher pulmonary vascular resistances. Despite this, pulmonary endarterectomy (PEA) was carried out in more men, and women received more frequently pulmonary vasodilators exclusively. The 2014–2019 interval was associated with a better survival only among women. Interestingly, women had a more distal disease during this second period of time. (4) Conclusions: Even though women were older, and received invasive treatments less frequently, mortality was similar in both sexes. The introduction of balloon pulmonary angioplasty and the improvement of pulmonary endarterectomy, especially during the last years, could be associated with a survival benefit among women.

Pulmonary Arterial Hypertension (PAH) is a severe complication of Connective Tissue Disease (CTD), with remarkable morbidity and mortality. However, the molecular and genetic basis of CTD-PAH remains incompletely understood. This study aimed to screen for genetic defects in a cohort of patients with CTD-PAH, using a PAH-specific panel of 35 genes. During recruitment, 79 patients were studied, including 59 Systemic Sclerosis patients (SSc) and 69 females. Disease-associated variants were observed in nine patients: 4 pathogenic/likely pathogenic variants in 4 different genes (TBX4, ABCC8, KCNA5 and GDF2/BMP9) and 5 Variants of Unknown Significance (VUS) in 4 genes (ABCC8, NOTCH3, TOPBP1 and CTCFL). One patient with mixed CTD had a frameshift pathogenic variant in TBX4. Two patients with SSc-PAH carried variants in ABCC8. A patient diagnosed with Systemic Lupus Erythematous (SLE) presented a pathogenic nonsense variant in GDF2/BMP9. Another patient with SSc-PAH presented a pathogenic variant in KCNA5. Four patients with SSc-PAH carried a VUS in NOTCH1, CTCFL, CTCFL and TOPBP1, respectively. These findings suggest that genetic factors may contribute to Pulmonary Vascular Disease (PVD) in CTD patients.

This multicenter, randomized, double-blind, placebo-controlled study assessed ambrisentan or placebo in patients with inoperable chronic thromboembolic pulmonary hypertension. Futility of enrollment led to early termination. Trends of improvement in favor of ambrisentan versus placebo in the primary and some secondary endpoints were observed; adverse event profiles were similar between groups.

This study aimed to evaluate the feasibility of a noninvasive operability assessment of chronic thromboembolic pulmonary hypertension (CTEPH) based on multidetector computed tomographic angiography (MCTA). Up to 176 patients were evaluated from January 2016 to April 2018. Throughout the first phase, the initial surgical decision was made based on MCTA with further analysis of pulmonary angiography (PA) in order to evaluate in which cases the initial decision was not modified by PA. During the second phase, PA was limited to patients judged inoperable based on MCTA or those whose assessment was not possible. Patients deemed operable (50%) based on MCTA along the first phase had been adequately classified, as PA did not modify the initial decision in all but one patient. Comparable results were obtained throughout the implementation phase. Regarding operated patients, the decision of operability was based solely on MCTA in 94% of those with level I disease, in 75% with level II, and 54% with level III. This approach enabled shorter periods of time to complete surgical assessment and the avoidance of PA-related morbidity. Baseline parameters, postoperative measures, and survival rates at 1 year after surgery were comparable in both phases. Noninvasive operability assessment is feasible in a subset of CTEPH patients and optimizes surgical candidacy evaluation.