Bosentan for Treatment of Inoperable Chronic Thromboembolic Pulmonary Hypertension

Pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension: a systematic review

BACKGROUND

Pulmonary thromboendarterectomy (PTE) is the gold standard treatment for patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, the results are poorly quantified outside a few registry reports and several individual centers.

METHODS

A systematic review was performed searching five electronic databases assessing the outcomes for adult patients undergoing PTE for CTEPH. All articles that reported mortality data were included. Primary outcome measures were early/inpatient mortality; secondary outcomes were survival, pulmonary haemodynamics, morbidity and functional status following PTE for CTEPH. Results were pooled via a meta-analysis of proportions and meta-regression.

RESULTS

A total of 5,717 studies were identified, yielding sixty-one relevant papers. Thirty-day mortality ranged from 0.8% to 24.4%, and on meta-analysis was 8.4% [95% confidence interval (CI): 7.2-9.6%]. Mortality was noted to decrease with increasing center volume of PTE cases (P<0.01). Residual pulmonary hypertension was reported in 8.2% to 44.5% of patients.

CONCLUSIONS

CTEPH is associated with acceptable short-term mortality and an improvement in pulmonary hemodynamics. With increasing volume of experience and ongoing developments over time peri-operative mortality continues to decrease.

Surgical Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension is a progressive disease, which may lead to severe right ventricular dysfunction and debilitating symptoms. Pulmonary thromboendarterectomy (PTE) provides the best opportunity for complete resolution of obstructing thromboembolic disease and functional improvement in appropriately selected patients. In this article, the authors review preoperative workup, patient selection, operative technique, postoperative care, and outcomes after PTE.

Chronic Thromboembolic Pulmonary Hypertension: An Update

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease observed in a small proportion of patients after acute pulmonary embolism (PE). CTEPH has a high morbidity and mortality rate, related to the PH severity, and a poor prognosis, which mirrors the right ventricular dysfunction involvement. Pulmonary endarterectomy (PEA) reduces pulmonary vascular resistance, making it the treatment of choice and should be offered to operable CTEPH patients, as significant symptomatic and prognostic improvement has been observed. Moreover, these patients may also benefit from the advances made in surgical techniques and pulmonary hypertension-specific medication. However, not all patients are eligible for PEA surgery, as some have either distal pulmonary vascular obstruction and/or significant comorbidities. Therefore, surgical candidates should be carefully selected by an interprofessional team in expert centers. This review aims at making an overview of the risk factors and latest developments in diagnostic tools and treatment options for CTEPH.

Chronic thromboembolic pulmonary hypertension: anticoagulation and beyond

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication in pulmonary embolism (PE) survivors, characterized by chronic vascular occlusion and pulmonary hypertension. The identification and diagnosis of CTEPH requires a stepwise approach, starting with symptom evaluation, functional evaluation, screening imaging, and progressing to interventional hemodynamic assessment. On the backbone of anticoagulation, CTEPH management necessitates a multidisciplinary approach. Surgical pulmonary thromboendarterectomy (PTE) is the only potentially curative option. In nonoperable disease or residual disease after PTE, interventional balloon pulmonary angioplasty and/or pulmonary-vasodilator therapies can be offered, in collaboration with interventional and vascular pulmonary colleagues. As it is a disease that can cause high morbidity and mortality, CTEPH requires a high index of suspicion to diagnose and treat in patients following PE.

Chronic thromboembolic pulmonary hypertension: Initial experience of patients undergoing pulmonary thromboendarterectomy

INTRODUCTION AND OBJECTIVES

Pulmonary endarterectomy (PEA) is a potentially curative procedure in patients with chronic thromboembolic pulmonary hypertension (CTEPH). This study reports the initial experience of a Portuguese PH center with patients undergoing PEA at an international surgical reference center.

METHODS

Prospective observational study of consecutive CTEPH patients followed at a national PH center, who underwent PEA at an international surgical reference center between October 2015 and March 2019. Clinical, functional, laboratory, imaging and hemodynamic parameters were obtained in the 12 months preceding the surgery and repeated between four and six months after PEA.

RESULTS

27 consecutive patients (59% female) with a median age of 60 (49-71) years underwent PEA. During a median follow-up of 34 (21-48) months, there was an improvement in functional class in all patients, with only one cardiac death. From a hemodynamic perspective, there was a reduction in mean pulmonary artery pressure from 48 (42-59) mmHg to 26 (22-38) mmHg, an increase in cardiac output from 3.3 (2.9-4.0) L/min to 4.9 (4.2-5.5) L/min and a reduction in pulmonary vascular resistance from 12.1 (7.2-15.5) uW to 3.5 (2.6-5,2) uW. During the follow-up, 44% (n=12) of patients had no PH criteria, 44% (n=12) had residual PH and 11% (n=3) had PH recurrence. There was a reduction of N-terminal pro-B-type natriureticpeptide from 868 (212-1730) pg/mL to 171 (98-382) pg/mL. Rright ventricular systolic function parameters revealed an improvement in longitudinal systolic excursion and peak velocity of the plane of the tricuspid ring from 14 (13-14) mm and 9 (8-10) cm/s to 17 (16-18) mm and 13 (11-15) cm/s, respectively. Of the 26 patients with preoperative right ventricular dysfunction, 85% (n=22) recovered. The proportion of patients on specific vasodilator therapy decreased from 93% to 44% (p<0.001) and the proportion of those requiring oxygen therapy decreased from 52% to 26% (p=0.003). The six-minute walk test distance increased by about 25% compared to the baseline and only eight patients had significant desaturation during the test.

CONCLUSION

Pulmonary endarterectomy performed at an experienced high-volume center is a safe procedure with a very favorable medium-term impact on functional, hemodynamic and right ventricular function parameters in CTEPH patients with operable disease. It is possible for PH centers without PEA differentiation to refer patients safely and effectively to an international surgical center in which air transport is necessary.

A model for estimating the health economic impact of earlier diagnosis of chronic thromboembolic pulmonary hypertension

Background

Diagnostic delay of chronic thromboembolic pulmonary hypertension (CTEPH) exceeds 1 year, contributing to higher mortality. Health economic consequences of late CTEPH diagnosis are unknown. We aimed to develop a model for quantifying the impact of diagnosing CTEPH earlier on survival, quality-adjusted life-years (QALYs) and healthcare costs.

Material and methods

A Markov model was developed to estimate lifelong outcomes, depending on the degree of delay. Data on survival and quality of life were obtained from published literature. Hospital costs were assessed from patient records (n=498) at the Amsterdam UMC – VUmc, which is a Dutch CTEPH referral center. Medication costs were based on a mix of standard medication regimens.

Results

For 63-year-old CTEPH patients with a 14-month diagnostic delay of CTEPH (median age and delay of patients in the European CTEPH Registry), lifelong healthcare costs were estimated at EUR 117 100 for a mix of treatment options. In a hypothetical scenario of maximal reduction of current delay, improved survival was estimated at a gain of 3.01 life-years and 2.04 QALYs. The associated cost increase was EUR 44 654, of which 87% was due to prolonged medication use. This accounts for an incremental cost–utility ratio of EUR 21 900/QALY.

Conclusion

Our constructed model based on the Dutch healthcare setting demonstrates a substantial health gain when CTEPH is diagnosed earlier. According to Dutch health economic standards, additional costs remain below the deemed acceptable limit of EUR 50 000/QALY for the particular disease burden. This model can be used for evaluating cost-effectiveness of diagnostic strategies aimed at reducing the diagnostic delay.

This constructed model based on the Dutch healthcare setting can be used for evaluating cost-effectiveness of diagnostic strategies aimed at reducing the diagnostic delay of chronic thromboembolic pulmonary hypertensionhttps://bit.ly/35yXPM3

Selexipag for the treatment of chronic thromboembolic pulmonary hypertension

Treatment options for inoperable chronic thromboembolic pulmonary hypertension (CTEPH) remain limited. Selexipag, an oral selective IP prostacyclin-receptor agonist approved for pulmonary arterial hypertension, is a potential treatment option for CTEPH.In this multicentre, randomised, double-blind, placebo-controlled study, 78 Japanese patients with inoperable CTEPH or persistent/recurrent pulmonary hypertension after pulmonary endarterectomy and/or balloon pulmonary angioplasty were randomly assigned to receive placebo or selexipag. The primary endpoint was the change in pulmonary vascular resistance (PVR) from baseline to week 20. The secondary endpoints were changes in other haemodynamic parameters, 6-min walk distance (6 WMD), Borg Dyspnoea Scale score, World Health Organisation (WHO) functional class, EuroQol 5 dimensions 5-level and N-terminal pro-brain natriuretic peptide.The change in PVR was -98.2±111.3 dyn·s·cm^-5 and -4.6±163.6 dyn·s·cm^-5 in the selexipag and placebo groups, respectively (mean difference, -93.5 dyn·s·cm^-5; 95% confidence interval, -156.8, -30.3; p=0.006). The changes in cardiac index (p<0.001) and Borg Dyspnoea Scale score (p=0.036) were also significantly improved over placebo. 6WMD and WHO functional class were not significantly improved. The common adverse events in the selexipag group were corresponded to those generally observed following a prostacyclin analogue is administered.Selexipag significantly improved PVR and other haemodynamic variables in patients with CTEPH, although exercise capacity remained unchanged. Further large-scale investigation is necessary to prove the role of selexipag in CTEPH.

Interventional Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension is a distinct form of pulmonary hypertension characterized by the nonresolution of thrombotic material in the pulmonary tree; whenever feasible and safe, first-line treatment should be pulmonary thromboendarterectomy. In patients who are not operative candidates, balloon pulmonary angioplasty (BPA) has emerged as an effective treatment modality that results in improvements in functional class, symptoms, hemodynamics, 6-minute walk distance, and right ventricular and pulmonary artery mechanics. Careful attention to procedural technique and rapid identification and treatment of complications are critical for a successful BPA program.

Chronic thromboembolic pulmonary hypertension in Australia and New Zealand: An analysis of the PHSANZ registry

BACKGROUND AND OBJECTIVE

Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious condition occurring in 2%-4% of patients after acute pulmonary embolism. Pulmonary endarterectomy (PEA) is a potential cure for technically operable disease. The epidemiology and long-term outcomes of CTEPH have not been previously described in Australia and New Zealand.

METHODS

Data were extracted from the Pulmonary Hypertension Society of Australia and New Zealand (PHSANZ) registry for patients diagnosed with CTEPH between January 2004 and March 2020. Baseline characteristics, treatment strategies, outcome data and long-term survival are reported.

RESULTS

A total of 386 patients were included with 146 (37.8%) undergoing PEA and 240 (62.2%) in the non-PEA group. PEA patients were younger (55 ± 16 vs. 62 ± 16 years, p < 0.001) with higher baseline 6-min walk distance (6MWD; 405 ± 122 vs. 323 ± 146 m, p = 0.021), whilst both groups had similar baseline pulmonary haemodynamics. Pulmonary hypertension-specific therapy was used in 54% of patients post-PEA and 88% in the non-PEA group. The 1-, 3- and 5-year survival rates were 93%, 87% and 84% for the PEA group compared to 86%, 73% and 62%, respectively, for the non-PEA group (p < 0.001). Multivariate survival analysis showed baseline 6MWD was an independent predictor of survival in both operated and medically managed patients.

CONCLUSION

In this first multicentre report of CTEPH in Australia and New Zealand, long-term survival is comparable to that in other contemporary CTEPH registries. However, PEA was only performed in a minority of CTEPH patients (37.8%) and significantly less than overseas reports. Greater awareness of PEA and improved patient access to experienced CTEPH centres are important priorities.

Global trends in chronic thromboembolic pulmonary hypertension clinical trials and dissemination of results

Treatment options for chronic thromboembolic pulmonary hypertension (CTEPH) are rapidly expanding. The purpose of this study is to identify trends in CTEPH clinical trials and the publication of results. We performed a worldwide review of completed and ongoing clinical trials through searching the ClinicalTrials.gov database and the World Health Organization International Clinical Trials Registry Platform for "CTEPH" and related terms. Entries were classified as pharmaceutical/procedural interventions (Group 1), all other clinical trials (Group 2) and patient registries (Group 3). Trial characteristics and national affiliation were recorded. PubMed was searched for related publications. There were 117 clinical trials registry entries after removing duplicates and non-target records. Group 1 comprised 29 pharmaceutical, 15 procedural, and four combined interventions starting in 2005, 2010, and 2016, respectively. Riociguat and balloon pulmonary angioplasty were the most frequent pharmaceutical and procedural interventions, respectively. The proportion of procedural trials increased over time from 0% of those in 2005-2009 to 29% in 2010-2014 and 54% in 2015-2020. There were 56 entries in Group 2 and 13 in Group 3. Japan was the most frequent national affiliation and the most frequent participating country, present in 28% of all trials. The proportion of entries with published results was highest with Group 3 (62%) and lowest with Group 1 (27%). Thirty percent of all publications occurred in 2020. In conclusion, CTEPH clinical trials are increasingly procedural based, with growth largely attributable to Japan and balloon pulmonary angioplasty. Most trials have not published, but results from balloon pulmonary angioplasty clinical trials are anticipated soon.

Sex Differences in Chronic Thromboembolic Pulmonary Hypertension. Treatment Options over Time in a National Referral Center

(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.

Comparative Efficacy and Safety of Targeted Therapies for Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review and Network Meta-Analysis

Background

There is significant controversy relating to whether chronic thromboembolic pulmonary hypertension (CTEPH) can be treated with pulmonary arterial hypertension- (PAH-) targeted therapies and which therapy is the optimal choice for patients. A large number of randomized controlled trials (RCTs) have compared PAH-targeted therapies with placebo or conventional therapies. In this study, we aimed to compare all of the PAH-targeted medications that are used to treat CTEPH and rank their efficacy by the application of network meta-analysis (NMA).

Methods

We searched PubMed, EMBASE, Web of Science, the Cochrane Central Register, https://clinicaltrials.gov, and who.int/trialsearch/, for relevant RCTs published up to January 2020. In addition to traditional meta-analysis, we also performed NMA in our systematic review, as deployed in a previous protocol (PROSPERO: CRD42020173765).

Results

Our study identified eight eligible RCTs that evaluated seven PAH-targeted therapies in 703 patients with CTEPH. NMA revealed that riociguat was ranked first as the most optimized therapy for ameliorating the 6-minute walk distance with a probability of 80.4%. Bosentan was significantly better than others with regard to reducing brain natriuretic peptide/N-terminal pro-B-type natriuretic peptide with a probability of 84.3%. Sildenafil was identified as the best drug in terms of improving the New York Heart Association/World Health Organization functional class with a probability of 87.3%. Treprostinil and macitentan were more beneficial than other drugs in reducing pulmonary vascular resistance and lowering the incidence of clinical worsening with probabilities of 86.2% and 79.2%, respectively.

Conclusion

Analysis revealed positive advantages for the use of PAH-targeted drugs in patients with CTEPH. Overall, treprostinil and riociguat were superior to all other PAH-targeted medications in most of the outcomes investigated.

Chronic thromboembolic pulmonary hypertension: initial experience of patients undergoing pulmonary thromboendarterectomy

INTRODUCTION AND OBJECTIVES

Pulmonary endarterectomy (PEA) is a potentially curative procedure in patients with chronic thromboembolic pulmonary hypertension (CTEPH). This study reports the initial experience of a Portuguese PH center with patients undergoing PEA at an international surgical reference center.

METHODS

Prospective observational study of consecutive CTEPH patients followed at a national PH center, who underwent PEA at an international surgical reference center between October 2015 and March 2019. Clinical, functional, laboratory, imaging and hemodynamic parameters were obtained in the 12 months preceding the surgery and repeated between four and six months after PEA.

RESULTS

27 consecutive patients (59% female) with a median age of 60 (49-71) years underwent PEA. During a median follow-up of 34 (21-48) months, there was an improvement in functional class in all patients, with only one cardiac death. From a hemodynamic perspective, there was a reduction in mean pulmonary artery pressure from 48 (42-59) mmHg to 26 (22-38) mmHg, an increase in cardiac output from 3.3 (2.9-4.0) L/min to 4.9 (4.2-5.5) L/min and a reduction in pulmonary vascular resistance from 12.1 (7.2-15.5) uW to 3.5 (2.6-5, 2) uW. During the follow-up, 44% (n=12) of patients had no PH criteria, 44% (n=12) had residual PH and 11% (n = 3) had PH recurrence. There was a reduction of N-terminal pro-B-type natriureticpeptide from 868 (212-1730) pg/mL to 171 (98-382) pg/mL. Rright ventricular systolic function parameters revealed an improvement in longitudinal systolic excursion and peak velocity of the plane of the tricuspid ring from 14 (13-14) mm and 9 (8-10) cm/s to 17 (16-18) mm and 13 (11-15) cm/s, respectively. Of the 26 patients with preoperative right ventricular dysfunction, 85% (n=22) recovered. The proportion of patients on specific vasodilator therapy decreased from 93% to 44% (p<0.001) and the proportion of those requiring oxygen therapy decreased from 52% to 26% (p=0.003). The six-minute walk test distance increased by about 25% compared to the baseline and only eight patients had significant desaturation during the test.

CONCLUSION

Pulmonary endarterectomy performed at an experienced high-volume center is a safe procedure with a very favorable medium-term impact on functional, hemodynamic and right ventricular function parameters in CTEPH patients with operable disease. It is possible for PH centers without PEA differentiation to refer patients safely and effectively to an international surgical center in which air transport is necessary.

Evaluation and management of patients with chronic thromboembolic pulmonary hypertension - consensus statement from the ISHLT

ISHLT members have recognized the importance of a consensus statement on the evaluation and management of patients with chronic thromboembolic pulmonary hypertension. The creation of this document required multiple steps, including the engagement of the ISHLT councils, approval by the Standards and Guidelines Committee, identification and selection of experts in the field, and the development of 6 working groups. Each working group provided a separate section based on an extensive literature search. These sections were then coalesced into a single document that was circulated to all members of the working groups. Key points were summarized at the end of each section. Due to the limited number of comparative trials in this field, the document was written as a literature review with expert opinion rather than based on level of evidence.

Chronic thromboembolic pulmonary hypertension: a review

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension resulting from obstruction of the pulmonary artery by fibrotic thromboembolic material, usually initiated by recurrent or incomplete resolution of pulmonary embolism. This distinct form of pulmonary hypertension is classified under Group 4 of the World Health Organization classification. Further investigations are usually initiated, with transthoracic echocardiography followed by right heart catheterisation and pulmonary angiography as the gold standard. Definitive treatment is usually in the form of surgical pulmonary endarterectomy. Inoperable CTEPH is medically treated with pharmacological agents such as phosphodiesterase Type 5 inhibitors, endothelin receptor antagonists, soluble guanylate cyclase stimulators and prostacyclin. Recent developments have made balloon pulmonary angioplasty a viable option as well.

Exercise tolerance and quality of life in hemodynamically partially improved patients with chronic thromboembolic pulmonary hypertension treated with balloon pulmonary angioplasty

The efficacy of extensive balloon pulmonary angioplasty (BPA) beyond hemodynamic improvement in chronic thromboembolic pulmonary hypertension (CTEPH) patients has been verified. However, the relationship between extensive BPA in CTEPH patients after partial hemodynamic improvement and exercise tolerance or quality of life (QOL) remains unclear. We prospectively enrolled 22 CTEPH patients (66±10 years, females: 59%) when their mean pulmonary artery pressure initially decreased to <30 mmHg during BPA sessions. Hemodynamic and echocardiographic data, cardiopulmonary exercise testing, and QOL scores using the 36-item short form questionnaire (SF-36) were evaluated at enrollment (entry), just after the final BPA session (finish), and at the 6-month follow-up (follow-up). We analyzed whether extensive BPA improves exercise capacity and QOL scores over time. Moreover, the clinical characteristics leading to improvement were elucidated. The peak oxygen uptake (VO₂) showed significant improvement at entry, finish, and follow-up (17.3±5.5, 18.4±5.9, and 18.9±5.3 mL/kg/min, respectively; P<0.001). Regarding the QOL, the physical component summary (PCS) scores significantly improved (32±11, 38±13, and 43±13, respectively; P<0.001), but the mental component summary scores remained unchanged. Linear regression analysis revealed that age and a low peak VO2 at entry were predictors of improvement in peak VO2, while low PCS scores and low TAPSE at entry were predictors of improvement in PCS scores. In conclusion, extensive BPA led to improved exercise tolerance and physical QOL scores, even in CTEPH patients with partially improved hemodynamics.

Results of Macitentan in Japanese Patients With Chronic Thromboembolic Pulmonary Hypertension - A Prospective, Multicenter, Open-Label, Single-Arm, Phase 3 Study

Background: Macitentan, an endothelin-receptor antagonist, is approved in Japan for the treatment of pulmonary arterial hypertension (PAH). This study evaluated the use of macitentan for chronic thromboembolic pulmonary hypertension (CTEPH) in Japanese patients. Methods and Results: This open-label single-arm Phase 3 study evaluated the efficacy and safety of oral macitentan 10 mg (once daily) in Japanese CTEPH patients. The study was prematurely discontinued due to the sponsor's decision to not develop macitentan 10 mg further for the indication of CTEPH (unrelated to safety concerns). Of the 9 patients enrolled in the study, 4 completed 24 weeks of treatment. The mean (±SD) ratio of pulmonary vascular resistance (PVR) at Week 16 to baseline was 71.9±34.3%. The mean (±SD) decreases in PVR and the PVR index (PVRI) from baseline to Week 16 were 181.4±243.9 dyn·s/cm5 and 280.6±366.0 dyn·s·m2/cm5, respectively. The mean (±SD) increase in the 6-min walk distance from baseline to Week 24 was 44.3±46.8 m. All treatment-emergent adverse events (TEAEs) were mild or moderate in severity, except for 1 serious TEAE of angioplasty reported in 1/9 patients that was severe in intensity. Conclusions: Definite conclusions regarding the efficacy of macitentan 10 mg in Japanese patients with CTEPH cannot be drawn because of premature study discontinuation. No safety concerns were observed, and the safety profile was consistent with previously reported studies in CTEPH and PAH patients.

Raising the bar to ultradisciplinary collaborations in management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is an underdiagnosed and potentially fatal subgroup of pulmonary hypertension, if left untreated. Clinical signs include exertional dyspnea and non-specific symptoms. Diagnosis requires multimodality imaging and heart catheterization. Pulmonary endarterectomy, an open heart surgery, is the gold standard treatment of choice in selected patients in specialized centers. Targeted medical therapy and balloon pulmonary angioplasty can be effective in high-risk patients with significant comorbidities, distal pulmonary vascular obstructions, or recurrent/persistent pulmonary hypertension after pulmonary endarterectomy. Currently, there is a limited number of data regarding novel coronavirus-2019 infection in patients with chronic thromboembolic pulmonary hypertension and the changing spectrum of the disease during the pandemic. Challenging times during this outbreak due to healthcare crisis and relatively higher case-fatality rates require convergence; that is an ultradisciplinary collaboration, which crosses disciplinary and sectorial boundaries to develop integrated knowledge and new paradigms. Management strategies for the "new normal" such as virtual care, preparedness for further threats, redesigned standards and working conditions, reevaluation of specific recommendations, and online collaborations for optimal decisions for chronic thromboembolic pulmonary hypertension patients may change the poor outcomes.

Chronic Thromboembolic Pulmonary Hypertension Medical Management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a common long-term complication of pulmonary embolism characterized by thromboembolic obstruction of the pulmonary arteries, vascular arteriopathy, vascular remodeling, and ultimately pulmonary hypertension (PH). Although pulmonary endarterectomy (PEA) surgery is the standard of care, approximately 40% of patients in the international CTEPH registry were deemed inoperable. In addition to lifelong anticoagulation, the cornerstone of PH-specific medical management is riociguat, a soluble guanylate cyclase stimulator. Medical management should be started early in CTEPH patients and may be used as a bridge to PEA surgery or balloon pulmonary angiography. Medical management is indicated for inoperable CTEPH patients and patients who have recurrence of PH after PEA surgery.

ERS statement on chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism, either symptomatic or not. The occlusion of proximal pulmonary arteries by fibrotic intravascular material, in combination with a secondary microvasculopathy of vessels <500 µm, leads to increased pulmonary vascular resistance and progressive right heart failure. The mechanism responsible for the transformation of red clots into fibrotic material remnants has not yet been elucidated. In patients with pulmonary hypertension, the diagnosis is suspected when a ventilation/perfusion lung scan shows mismatched perfusion defects, and confirmed by right heart catheterisation and vascular imaging. Today, in addition to lifelong anticoagulation, treatment modalities include surgery, angioplasty and medical treatment according to the localisation and characteristics of the lesions.This statement outlines a review of the literature and current practice concerning diagnosis and management of CTEPH. It covers the definitions, diagnosis, epidemiology, follow-up after acute pulmonary embolism, pathophysiology, treatment by pulmonary endarterectomy, balloon pulmonary angioplasty, drugs and their combination, rehabilitation and new lines of research in CTEPH.It represents the first collaboration of the European Respiratory Society, the International CTEPH Association and the European Reference Network-Lung in the pulmonary hypertension domain. The statement summarises current knowledge, but does not make formal recommendations for clinical practice.

Factors contributing to exercise capacity in chronic thromboembolic pulmonary hypertension with near-normal hemodynamics

BACKGROUND

Despite improved survival for patients with chronic thromboembolic pulmonary hypertension (CTEPH) due to progressive medical and interventional treatment, impaired exercise capacity remains common due to poorly understood mechanisms. We aimed to clarify the exercise capacity of CTEPH patients with near-normal pulmonary hemodynamics and evaluate its determinants among the hemodynamic, peripheral (e.g., oxygen use by the peripheral tissues), and muscular (e.g., skeletal muscle strength) factors.

METHODS

Three hundred and twenty-nine patients with CTEPH (mean age, 63 ± 12 years; men/women, 73/256) with a near-normal mean pulmonary artery pressure (≤30 mm Hg) at rest were enrolled. We assessed exercise capacity by peak oxygen consumption (peak VO₂) using cardiopulmonary exercise testing with a right heart catheter. We also measured the 6-minute walk distance (6MWD) and quadriceps muscle strength.

RESULTS

The mean pulmonary artery pressure was 19 ± 4 mmHg and mean cardiac output was 4.8 ± 1.5 L/min at rest. The mean 6MWD was 444 ± 101 m, while the mean peak VO₂ was 14.4 ± 3.9 mL/min/kg. A multivariate model that predicted 6MWD included quadriceps strength (β = 0.45, p < 0.001) and peak arterial venous oxygen difference (β = 0.29, p < 0.001). In contrast, the peak VO₂ was best correlated with mPAP-CO slope (β = -0.30, p < 0.001), followed by quadriceps strength and peak arterial venous oxygen difference.

CONCLUSIONS

The 6MWD performance may be significantly influenced by peripheral oxygen use and muscular factors, while peak VO₂ is influenced by hemodynamic and peripheral factors in CTEPH patients with near-normal hemodynamics.

Chronic Thromboembolic Pulmonary Hypertension - What Have We Learned From Large Animal Models

Chronic thrombo-embolic pulmonary hypertension (CTEPH) develops in a subset of patients after acute pulmonary embolism. In CTEPH, pulmonary vascular resistance, which is initially elevated due to the obstructions in the larger pulmonary arteries, is further increased by pulmonary microvascular remodeling. The increased afterload of the right ventricle (RV) leads to RV dilation and hypertrophy. This RV remodeling predisposes to arrhythmogenesis and RV failure. Yet, mechanisms involved in pulmonary microvascular remodeling, processes underlying the RV structural and functional adaptability in CTEPH as well as determinants of the susceptibility to arrhythmias such as atrial fibrillation in the context of CTEPH remain incompletely understood. Several large animal models with critical clinical features of human CTEPH and subsequent RV remodeling have relatively recently been developed in swine, sheep, and dogs. In this review we will discuss the current knowledge on the processes underlying development and progression of CTEPH, and on how animal models can help enlarge understanding of these processes.

Oxygen Pathway Limitations in Patients With Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Exertional intolerance is a limiting and often crippling symptom in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Traditionally the pathogenesis has been attributed to central factors, including ventilation/perfusion mismatch, increased pulmonary vascular resistance, and right heart dysfunction and uncoupling. Pulmonary endarterectomy and balloon pulmonary angioplasty provide substantial improvement of functional status and hemodynamics. However, despite normalization of pulmonary hemodynamics, exercise capacity often does not return to age-predicted levels. By systematically evaluating the oxygen pathway, we aimed to elucidate the causes of functional limitations in patients with CTEPH before and after pulmonary vascular intervention.

METHODS

Using exercise cardiac magnetic resonance imaging with simultaneous invasive hemodynamic monitoring, we sought to quantify the steps of the O₂ transport cascade from the mouth to the mitochondria in patients with CTEPH (n=20) as compared with healthy participants (n=10). Furthermore, we evaluated the effect of pulmonary vascular intervention (pulmonary endarterectomy or balloon angioplasty) on the individual components of the cascade (n=10).

RESULTS

Peak Vo₂ (oxygen uptake) was significantly reduced in patients with CTEPH relative to controls (56±17 versus 112±20% of predicted; P<0.0001). The difference was attributable to impairments in multiple steps of the O₂ cascade, including O₂ delivery (product of cardiac output and arterial O₂ content), skeletal muscle diffusion capacity, and pulmonary diffusion. The total O₂ extracted in the periphery (ie, ΔAVo₂ [arteriovenous O₂ content difference]) was not different. After pulmonary vascular intervention, peak Vo₂ increased significantly (from 12.5±4.0 to 17.8±7.5 mL/[kg·min]; P=0.036) but remained below age-predicted levels (70±11%). The O₂ delivery was improved owing to an increase in peak cardiac output and lung diffusion capacity. However, peak exercise ΔAVo₂ was unchanged, as was skeletal muscle diffusion capacity.

CONCLUSIONS

We demonstrated that patients with CTEPH have significant impairment of all steps in the O₂ use cascade, resulting in markedly impaired exercise capacity. Pulmonary vascular intervention increased peak Vo₂ by partly correcting O₂ delivery but had no effect on abnormalities in peripheral O₂ extraction. This suggests that current interventions only partially address patients' limitations and that additional therapies may improve functional capacity.

Revisiting a Distinct Entity in Pulmonary Vascular Disease: Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Chronic thromboembolic pulmonary hypertension (CTEPH) is a specific type of pulmonary hypertension (PH) and the major component of Group 4 pulmonary hypertension (PH). It is caused by pulmonary vasculature obstruction that leads to a progressive increase in pulmonary vascular resistance and, ultimately, to failure of the right ventricle. Pulmonary thromboendarterectomy (PEA) is the only definitive therapy, so a timely diagnosis and early referral to a specialized PEA center to determine candidacy is prudent for a favorable outcome. Percutaneous balloon pulmonary angioplasty (BPA) has a potential role in patients unsuitable for PEA. Medical therapy with riociguat is the only PH-specific medical therapy currently approved for the treatment of inoperable or persistent CTEPH. This review article aims to revisit CTEPH succinctly with a review of prevailing literature.

Characterization of a Cohort of Patients with Chronic Thromboembolic Pulmonary Hypertension from Northeastern Colombia (REHINO Study)

Chronic thromboembolic disease (CTEPH) is one of the causes for developing pulmonary hypertension (PH). PH is characterized by an increase in pulmonary vascular pressure and resistance, ultimately leading to chronic overload. This study describes the clinical, functional, and hemodynamic characteristics as well as the established treatment strategy for a cohort of patients diagnosed with CTEPH in Bucaramanga, Colombia. In Colombia, PH is considered as an orphan disease with limited epidemiological data. We aim to provide useful information in order to help guide future clinical decisions for PH treatment and prevention. We conducted a cross-sectional study, obtaining clinical data from patients under follow-up, over 18 years of age, with hemodynamic confirmation of CTEPH in two pulmonary outpatient centers in Bucaramanga, Colombia between 2012 and 2018. 35 patients with diagnosis of CTEPH were included. Mean age was 52.3 ± 17.9 years. The mean time between the onset of symptoms to diagnosis was 14 months. 71% had a previous thrombotic event and 69% had functional class III and IV according to the world health organization (WHO) criteria. Most of the patients were classified as at high risk of mortality according to the European Society of Cardiology (ESC) and the European Respiratory Society (ERS/ESC) criteria and 60% were referred to undergo thromboendarterectomy. Most of the patients were under monotherapy treatment with Bosentan, the most prescribed medication in both monotherapy and dual therapy. This study identified a high number of patients in advanced stages of CETPH due to late diagnosis, related to health care limitations. This resulted in worse prognosis and quality of life. In addition, low adherence to non-pharmacological interventions was evidenced in patients who were not candidates for thromboendarterectomy despite the onset of pharmacological therapy.

Risk stratification in patients with residual pulmonary hypertension after pulmonary endarterectomy

BACKGROUND

Few studies addressed the issue of risk stratification in patients with residual pulmonary hypertension (PH) after pulmonary endarterectomy (PEA). This study tested the potential added value of parameters that have not been included in existing risk models.

METHODS

We evaluated 546 consecutive patients with chronic thromboembolic pulmonary hypertension who underwent PEA and were followed-up for a median period of 58 months.

RESULTS

Among the 242 with residual PH, 27 died and had 127 a clinical worsening event. At univariable analysis, the parameters associated with poor survival were pulmonary vascular resistance (PVR) ≥425 dyn·s·cm^-5 (p ≤ 0.001), mean pulmonary artery pressure (mPAP) ≥38 mmHg (p = 0.003) and pulmonary artery compliance (CPA) ≤1.8 ml/mmHg (p = 0.014). In the bivariable models including either PVR or mPAP as first parameter, the addition of CPA was not statistically significant. The parameters associated with poor clinical worsening were CPA ≤1.8 ml/mmHg (p < 0.001), PVR ≥425 dyn·s·cm^-5 (p = 0.002), arterial oxygen tension (PaO2) ≤ 75 mmHg (p = 0.003), mPAP ≥38 mmHg (p = 0.008). In a multivariable analysis which included PVR ≥425 as the first parameter, the addition of both CPA ≤1.8 ml/mmHg and of PaO2 ≤ 75 mmHg significantly improved prognostic stratification (Harrel's C of the model = 0.64, p < 0.001). Noticeably, the lower tertile of the model's predictor index identified a subgroup of 91 patients who had an event rate numerically similar to that of patients without residual PH.

CONCLUSIONS

Risk stratification in residual PH can be refined if CPA and PaO2 are considered in association with standard hemodynamic parameters.

Perioperative Management of Pulmonary Hypertension. a Review

Pulmonary hypertension is a rare and progressive pathology defined by abnormally high pulmonary artery pressure mediated by a diverse range of aetiologies. It affects up to twenty-six individuals per one million patients currently living in the United Kingdom (UK), with a median life expectancy of 2.8 years in idiopathic pulmonary hypertension. The diagnosis of pulmonary hypertension is often delayed due to the presentation of non-specific symptoms, leading to a delay in referral to specialists services. The complexity of treatment necessitates a multidisciplinary approach, underpinned by a diverse disease aetiology from managing the underlying disease process to novel specialist treatments. This has led to the formation of dedicated specialist treatment centres within centralised UK cities. The article aimed to provide a concise overview of pulmonary hypertension's clinical perioperative management, including key definitions, epidemiology, pathophysiology, and risk stratification.

Evolution of randomized, controlled studies of medical therapy in chronic thromboembolic pulmonary hypertension

Although pulmonary endarterectomy (PEA) is the treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH), many patients have inoperable disease, and some have persistent or recurrent pulmonary hypertension (PH) after surgery. Alternative options (balloon pulmonary angioplasty (BPA) and PH-targeted medical therapy) are, therefore, required. Studies of medical therapies for CTEPH have evolved since Aerosolized Iloprost Randomized (AIR), the first randomized, controlled study of a PH-targeted therapy (inhaled iloprost) to include patients with CTEPH. Key learnings from these studies include the need to evaluate CTEPH separately from other types of PH, the importance of prospective operability adjudication as part of the protocol, and the need for sufficient duration to allow treatment benefits to become apparent. The 16-week Chronic Thromboembolic Pulmonary Hypertension Soluble Guanylate Cyclase-Stimulator Study 1 (CHEST-1) study was the first to operationalize these learnings, demonstrating a significant mean improvement in 6-minute walk distance (+46 m) and improvements in hemodynamic endpoints with riociguat versus placebo. Findings from previous studies will inform the design of future studies to address key issues related to combination medical therapy. Data on combinations of macitentan with phosphodiesterase type 5 inhibitors or oral prostanoids are available from MERIT, the first study to allow such regimens. No data on combinations including riociguat, the only licensed medical therapy for CTEPH, are available. Studies are also needed for multimodality treatment, including medical therapy plus BPA, and medical therapy as a bridge to PEA in selected operable patients. To address these issues and improve patient outcomes, it is vital that we learn from current studies to improve future trial design.

Endothelin receptor antagonists for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension is a devastating disease that leads to right heart failure and premature death. Endothelin receptor antagonists have shown efficacy in the treatment of pulmonary arterial hypertension.

OBJECTIVES

To evaluate the efficacy of endothelin receptor antagonists (ERAs) in pulmonary arterial hypertension.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and the reference sections of retrieved articles. The searches are current as of 4 November 2020.

SELECTION CRITERIA

We included randomised trials and quasi-randomised trials involving participants with pulmonary arterial hypertension.

DATA COLLECTION AND ANALYSIS

Two of five review authors selected studies, extracted data and assessed study quality according to established criteria. We used standard methods expected by Cochrane. The primary outcomes were exercise capacity (six-minute walk distance, 6MWD), World Health Organization (WHO) or New York Heart Association (NYHA) functional class, Borg dyspnoea scores and dyspnoea-fatigue ratings, and mortality.

MAIN RESULTS

We included 17 randomised controlled trials involving a total of 3322 participants. Most trials were of relatively short duration (12 weeks to six months). Sixteen trials were placebo-controlled, and of these nine investigated a non-selective ERA and seven a selective ERA.   We evaluated two comparisons in the review: ERA versus placebo and ERA versus phosphodiesterase type 5 (PDE5) inhibitor. The abstract focuses on the placebo-controlled trials only and presents the pooled results of selective and non-selective ERAs. After treatment, participants receiving ERAs could probably walk on average 25.06 m (95% confidence interval (CI) 17.13 to 32.99 m; 2739 participants; 14 studies; I2 = 34%, moderate-certainty evidence) further than those receiving placebo in a 6MWD. Endothelin receptor antagonists probably improved more participants' WHO functional class (odds ratio (OR) 1.41, 95% CI 1.16 to 1.70; participants = 3060; studies = 15; I2 = 5%, moderate-certainty evidence) and probably lowered the odds of functional class deterioration (OR 0.43, 95% CI 0.26 to 0.72; participants = 2347; studies = 13; I2 = 40%, moderate-certainty evidence) compared with placebo. There may be a reduction in mortality with ERAs (OR 0.78, 95% CI 0.58, 1.07; 2889 participants; 12 studies; I2 = 0%, low-certainty evidence), and pooled data suggest that ERAs probably improve cardiopulmonary haemodynamics and may reduce Borg dyspnoea score in symptomatic patients. Hepatic toxicity was not common, but may be increased by ERA treatment from 37 to 67 (95% CI 34 to 130) per 1000 over 25 weeks of treatment (OR 1.88, 95% CI 0.91 to 3.90; moderate-certainty evidence). Although ERAs were well tolerated in this population, several cases of irreversible liver failure caused by sitaxsentan have been reported, which led the licence holder for sitaxsentan to withdraw the product from all markets worldwide.  As planned, we performed subgroup analyses comparing selective and non-selective ERAs, and with the exception of mean pulmonary artery pressure, did not detect any clear subgroup differences for any outcome.

AUTHORS' CONCLUSIONS

For people with pulmonary arterial hypertension with WHO functional class II and III, endothelin receptor antagonists probably increase exercise capacity, improve WHO functional class, prevent WHO functional class deterioration, result in favourable changes in cardiopulmonary haemodynamic variables compared with placebo. However, they are less effective in reducing dyspnoea and mortality. The efficacy data were strongest in those with idiopathic pulmonary hypertension. The irreversible liver failure caused by sitaxsentan and its withdrawal from global markets emphasise the importance of hepatic monitoring in people treated with ERAs. The question of the effects of ERAs on pulmonary arterial hypertension has now likely been answered.. The combined use of ERAs and phosphodiesterase inhibitors may provide more benefit in pulmonary arterial hypertension; however, this needs to be confirmed in future studies.

Successful use of intravenous treprostinil as a bridge to pulmonary thromboendarterectomy

Chronic thromboembolic pulmonary hypertension (CTEPH) involves non-resolving thromboemboli in the pulmonary arteries. Treatment for CTEPH includes lifelong anticoagulation and determination of patients who have disease which is operable versus inoperable. Pulmonary arterial hypertension (PAH) targeted therapies are oftentimes used as a bridge to pulmonary thromboendarterectomy (PTE), though riociguat is the only Food and Drug Administration (FDA)-approved therapy for CTEPH. There is a paucity of data regarding the efficacy of other PAH therapies, particularly as a bridge to PTE. Here, we present a case report of severe CTEPH related to ventriculoatrial shunt in which intravenous treprostinil was used as a bridge to PTE.

Chronic Thromboembolic Pulmonary Hypertension: JACC Focus Seminar

Chronic thromboembolic pulmonary hypertension (CTEPH) is the result of pulmonary arterial obstruction by organized thrombotic material stemming from incompletely resolved acute pulmonary embolism. The exact incidence of CTEPH is unknown but appears to approximate 2.3% among survivors of acute pulmonary embolism. Although ventilation/perfusion scintigraphy has been supplanted by computed tomographic pulmonary angiography in the diagnostic approach to acute pulmonary embolism, it has a major role in the evaluation of patients with suspected CTEPH, the presence of mismatched segmental defects being consistent with the diagnosis. Diagnostic confirmation of CTEPH is provided by digital subtraction pulmonary angiography, preferably performed at a center familiar with the procedure and its interpretation. Operability assessment is then undertaken to determine if the patient is a candidate for potentially curative pulmonary endarterectomy surgery. When pulmonary endarterectomy is not an option, pulmonary arterial hypertension-targeted pharmacotherapy and balloon pulmonary angioplasty represent potential therapeutic alternatives.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Interventional and pharmacological management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by obstruction of the pulmonary vasculature, leading to increased pulmonary vascular resistance and ultimately right ventricular failure, the leading cause of death in non-operated patients. This article reviews the current management of CTEPH. The standard of care in CTEPH is pulmonary endarterectomy (PEA). However, up to 40% of patients with CTEPH are ineligible for PEA, and up to 51% develop persistent/recurrent PH after PEA. Riociguat is currently the only medical therapy licensed for treatment of inoperable or persistent/recurrent CTEPH after PEA based on the results of the Phase III CHEST-1 study. Studies of balloon pulmonary angioplasty (BPA) have shown benefits in patients with inoperable or persistent/recurrent CTEPH after PEA; however, data are lacking from large, prospective, controlled studies. Studies of macitentan in patients with inoperable CTEPH and treprostinil in patients with inoperable or persistent/recurrent CTEPH showed positive results. Combination therapy is under evaluation in CTEPH, and long-term data are not available. In the future, CTEPH may be managed by PEA, medical therapy or BPA - alone or in combination, according to individual patient needs. Patients should be referred to experienced centers capable of assessing and delivering all options.

Macitentan in infants and children with pulmonary hypertensive vascular disease. Feasibility, tolerability and practical issues - a single-centre experience

Macitentan is a safe and effective substance for treatment of adults with pulmonary arterial hypertension. Data on its use in paediatric patients are limited. In this single-centre prospective study, we report on our experience with macitentan in children focusing on applicability and practical aspects. Between December 2014 and July 2018, macitentan was introduced to paediatric patients according to a dosing protocol adjusted to body weight. Blood pressure, heart rate, saturation and clinical symptoms were recorded daily during introduction. Liver function parameters and haemoglobin levels were measured at baseline, four weeks and three months after initiation and after one year of treatment. Twenty-four patients (14 male, 10 female) were enrolled for treatment with macitentan. The mean age was 10.7 ± 7.6 years (range: 0.1 year-23 years). Fifteen out of 24 patients were World Health Organization functional class (FC) II, 7 patients in FC III and 2 patients in FC IV. Twenty out of 24 patients (83%) received additional advanced therapy with sildenafil and/or prostacyclines. We had two early discontinuations because of clinical relevant oedema. In the remaining 22 patients, macitentan was well tolerated. Liver function parameters and blood count levels remained stable during the observational time. The introduction of macitentan was feasible and mostly well tolerated in paediatric patients. Special attention should be paid to oedema during introduction of the drug. To the best of our knowledge, this is the first study to report on its applicability in infants and children. However, larger prospective trials are warranted to verify these preliminary findings.

Chronic Thromboembolic Pulmonary Hypertension: the Bedside

PURPOSE OF REVIEW

Chronic thromboembolic pulmonary hypertension (CTEPH), included in group 4 PH, is an uncommon complication of acute pulmonary embolism (PE), in which emboli in the pulmonary vasculature do not resolve but rather form into an organized scar-like obstruction which can result in right ventricular (RV) failure. Here we provide an overview of current diagnosis and management of CTEPH.

RECENT FINDINGS

CTEPH management is complex with treatments that range from surgery, percutaneous interventions, to medical therapies. Current CTEPH medical therapies have largely been repurposed from pulmonary arterial hypertension (PAH). The diagnosis of CTEPH can be challenging, requiring a multimodality approach to differentiate from disease mimics. While these treatments improve symptoms, they may not reverse the underlying pathology of CTEPH.

How should a physician approach the pharmacological management of chronic thromboembolic pulmonary hypertension?

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by the presence of organized thromboembolic material and proliferative fibrous intima occluding varying degrees of the pulmonary arteries, and is also accompanied by small vessel vasculopathy in occluded and non-occluded pulmonary vasculature. The similarity in hemodynamics and pathophysiology between CTEPH and group 1 pulmonary arterial hypertension provides the rationale for clinical use of pulmonary arterial hypertension (PAH)-specific therapy.

AREAS COVERED

The authors present the current knowledge concerning the updated therapeutic strategies in CTEPH, and try to illustrate the established and uncertain role of PAH-specific therapy and anticoagulation therapy. The real-world observational registries and landmark randomized controlled trials of PAH-specific drugs in CTEPH are emphasized in the manuscript.

EXPERT OPINION

Despite surgical and interventional therapies, which could provide effective and potential curable treatments, medical therapies are still the substantial and irreplaceable option for patients with CTEPH. More and more PAH-specific drugs have demonstrated favorable efficacy and safety profiles in patients with CTEPH. Additionally, anticoagulation therapy is also a substantial medical treatment in all CTEPH patients without contradiction. However, the benefit-to-risk balance in life-long anticoagulation and whether more individualized anticoagulation strategies are needed warrants further investigation.

Selexipag for Chronic Thromboembolic Pulmonary Hypertension in Japanese Patients - A Double-Blind, Randomized, Placebo-Controlled, Multicenter Phase II Study

BACKGROUND

Selexipag is an oral prostacyclin receptor (IP receptor) agonist with a non-prostanoid structure. This study examined its efficacy and safety in Japanese patients with non-operated or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS AND RESULTS

This Phase II study was a randomized, double-blind, placebo-controlled parallel-group comparison. The primary endpoint was a change in pulmonary vascular resistance (PVR) from baseline to week 17. The main analysis involved a per-protocol set group of 28 subjects. The change in PVR (mean±SD) after 17 weeks of treatment in the selexipag group was -104±191 dyn·s/cm5, whereas that in the placebo group was 26±180 dyn·s/cm5. Thus, the treatment effect after 17 weeks of selexipag treatment was calculated as -130±189 dyn·s/cm5(P=0.1553). Although the primary endpoint was not met, for the group not concomitantly using a pulmonary vasodilator the PVR in the selexipag group was significantly decreased compared with placebo group (P=0.0364). The selexipag group also showed improvement in total pulmonary resistance and cardiac index.

CONCLUSIONS

Selexipag treatment improved pulmonary hemodynamics in Japanese patients with CTEPH, but PVR did not show a significant difference between the selexipag and placebo groups. (Trial registration: JAPIC Clinical Trials Information [JapicCTI-111667]).

Long-term Outcomes After Pulmonary Endarterectomy in 499 Patients Over a 20-Year Period

BACKGROUND

Pulmonary endarterectomy (PEA) is a curative treatment for chronic thromboembolic pulmonary hypertension (CTEPH). Pulmonary hypertension (PH) after PEA is not uncommon, and its impact on long-term outcomes is poorly understood. We investigated the effects of residual PH on current long-term survival and on postoperative status.

METHODS

Data of 499 consecutive patients who underwent PEA between December 1995 and December 2014 were analyzed retrospectively. Kaplan-Meier survival analysis was used to estimate the survival rates with the 95% confidence interval.

RESULTS

Overall survival at 5, 10, and 15 years postoperatively was 84.8% ± 1.9%, 77.1% ± 2.7%, and 59.2% ± 5.3%, respectively. Survival after discharge at 5, 10, and 15 years was 93.9% ± 1.5%, 85.4% ± 2.6%, and 65.6% ± 5.8%, respectively. Of all, 166 patients had residual PH immediately after PEA and a poorer prognosis regarding freedom from CTEPH-related death. CTEPH-related survival at 10 years in patients with normal pulmonary artery pressure vs residual PH was 89.0% ± 2.7% vs 67.9% ± 4.7%, respectively (P < .001). There was a trend to CTEPH-related survival after discharge being affected by residual PH (P = .092). At follow-up, patients with residual PH had worse exercise tolerance (P < .001) and symptoms (P < .001) compared with those with normal pulmonary artery pressure. The probability of developing PH over time was 41.9% at 15 years.

CONCLUSIONS

Survival after hospital discharge is excellent for patients undergoing PEA. Postoperative PH is associated with more symptoms and poorer functional capacity. Patients who have clinically relevant postoperative PH should be monitored closely and may be candidates for additional medical therapy.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: State of the art

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Risk stratification in chronic thromboembolic pulmonary hypertension predicts survival

OBJECTIVES

To investigate if the pulmonary arterial hypertension (PAH) risk assessment tool presented in the 2015 ESC/ERS guidelines is valid for patients with chronic thromboembolic pulmonary hypertension (CTEPH) when taking pulmonary endarterectomy (PEA) into account. Design. Incident CTEPH patients registered in the Swedish PAH Registry (SPAHR) between 2008 and 2016 were included. Risk stratification performed at baseline and follow-up classified the patients as low-, intermediate-, or high-risk using the proposed ESC/ERS risk algorithm. Results. There were 250 CTEPH patients with median age (interquartile range) 70 (14) years, and 53% were male. Thirty-two percent underwent PEA within 5 (6) months. In a multivariable model adjusting for age, sex, and pharmacological treatment, patients with intermediate-risk or high-risk profiles at baseline displayed an increased mortality risk (Hazard Ratio [95% confidence interval]: 1.64 [0.69-3.90] and 5.39 [2.13-13.59], respectively) compared to those with a low-risk profile, whereas PEA was associated with better survival (0.38 [0.18-0.82]). Similar impact of risk profile and PEA was seen at follow-up. Conclusion. The ESC/ERS risk assessment tool identifies CTEPH patients with reduced survival. Furthermore, PEA improves survival markedly independently of risk group and age. Take home message: The ESC/ERS risk stratification for PAH predicts survival also in CTEPH patients, even when taking PEA into account.

Treatment of chronic thromboembolic pulmonary hypertension in a multidisciplinary team

Background:

Chronic thromboembolic pulmonary hypertension (CTEPH) may be treated with pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and medical therapy (MT). Assessment in a multidisciplinary team of experts (CTEPH team) is currently recommended for treatment decision making. The aim of the present study was to report the effects of such an interdisciplinary concept.

Methods and results:

A total of 160 patients were consulted by the CTEPH team between December 2015 and September 2018. Patient baseline characteristics, CTEPH team decisions and implementation rates of diagnostic and therapeutic procedures were analysed. Change in World Health Organization (WHO) functional class and survival rates were evaluated by treatment strategy. A total of 51 (32%) patients were assessed as operable and 109 (68%) were deemed inoperable. Thirty-one (61% of operable patients) underwent PEA. Patients treated with PEA, BPA(+MT) and MT alone were 50.9 ± 14.7, 62.9 ± 15.1 and 68.9 ± 12.7 years old, respectively. At the follow-up, PEA patients had the highest WHO functional class improvement. Patients treated with BPA(+MT) had significantly better survival than PEA (p = 0.04) and MT patients (p = 0.04; 2-year survival of 92%, 79% and 79%, respectively).

Conclusions:

The CTEPH team ensures that necessary diagnostic procedures are performed. A relatively low proportion of patients was assessed by the CTEPH team as operable and underwent surgery, which in survivors resulted in the best functional improvement. Although patients undergoing BPA(+MT) were older than patients treated with PEA, their survival was better than patients subjected to PEA or MT alone.

The reviews of this paper are available via the supplemental material section.

Comparison of Balloon Pulmonary Angioplasty and Pulmonary Vasodilators for Inoperable Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review and Meta-Analysis

Treatment options for chronic thromboembolic pulmonary hypertension (CTEPH) that is not amenable to thromboendarterectomy or is recurrent/persistent after thromboendarterectomy (inoperable CTEPH) include pulmonary vasodilators or balloon pulmonary angioplasty (BPA). We compared efficacy and safety outcomes of BPA with or without pulmonary vasodilators to pulmonary vasodilator therapy alone in patients with inoperable CTEPH. Observational and randomized trial data reporting outcomes for >5 patients with inoperable CTEPH were sought. Single-arm random effects meta-analyses were performed. The primary outcome was change in six-minute walk distance (6MWD). Secondary outcomes included safety; World Health Organization functional class (WHO FC); and change in mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index. Thirty-four studies with 1604 patients were eligible for analyses. Both treatments resulted in significant improvement in 6MWD (71.0 meters, 95% CI: 47.4–94.5 meters with BPA versus 47.8 meters, 95% CI: 34.5–61.2 meters with pulmonary vasodilators), PVR [−3.1 Wood Units (WU), 95% CI: −4.9 to −1.4 WU versus −1.6 WU, 95% CI: −2.4 to −0.8 WU] and mPAP (−14.8 mmHg, 95% CI: −18.2 to −11.5 mmHg versus −4.9 mmHg, 95% CI: −6.9 to −2.8 mmHg). Cardiac index was similar and most patients were WHO FC II and III after their respective interventions. More complications occurred in the BPA arm. In conclusion, BPA and pulmonary vasodilators both improve 6MWD and hemodynamics in patients with inoperable CTEPH. While BPA may offer greater functional and hemodynamic improvements, this technique carries the accompanying risks of an invasive procedure.

Diagnosis and Management of Pulmonary Hypertension in the Modern Era: Insights from the 6th World Symposium

The past 20 years have seen major advances in the diagnosis and management of pulmonary hypertension, a disease associated with significant morbidity and mortality. The 6th World Symposium in Pulmonary Hypertension (WSPH) took place in February 2018 and attempted to consolidate the current knowledge in the field into practical recommendations to help prioritize an action plan to improve patient outcomes and identify future research directions. In this review, we will summarize the highlights of the 6th WSPH proceedings, including revisions to the hemodynamic definitions and classification of the various types of pulmonary hypertension, genetic advances, approaches to risk stratification, and updated treatment algorithms.

Clinical Updates on the Diagnosis and Management of Chronic Thromboembolic Pulmonary Hypertension

Introduction: Chronic thromboembolic pulmonary hypertension (CTEPH) is a known sequela after acute pulmonary embolism (PE). It is a debilitating disease, and potentially fatal if left untreated. This review provides a clinically relevant overview of the disease and discusses the usefulness and limitations of the various investigational and treatment options. Methods: A PubMed search on articles relevant to pulmonary embolism, pulmonary hypertension, chronic thromboembolic pulmonary hypertension, pulmonary endarterectomy, and balloon pulmonary angioplasty were performed. A total of 68 articles were found to be relevant and were reviewed. Results: CTEPH occurs as a result of non-resolution of thrombotic material, with subsequent fibrosis and scarring of the pulmonary arteries. Risk factors have been identified, but the underlying mechanisms have yet to be fully elucidated. The cardinal symptom of CTEPH is dyspnoea on exertion, but the diagnosis is often challenging due to lack of awareness. The ventilation/perfusion scan is recommended for screening for CTEPH, with other modalities (eg. dual energy computed tomography pulmonary angiography) also being utilised in expert centres. Conventional pulmonary angiography with right heart catherisation is important in the final diagnosis of CTEPH. Conclusion: Operability assessment by a multidisciplinary team is crucial for the management of CTEPH, as pulmonary endarterectomy (PEA) remains the guideline recommended treatment and has the best chance of cure. For inoperable patients or those with residual disease post-PEA, medical therapy or balloon pulmonary angioplasty are potential treatment options. Keywords: Balloon pulmonary angioplasty, Chronic thromboembolic pulmonary hypertension, Pulmonary embolism, Pulmonary endarterectomy, Pulmonary hypertension