Prostacyclin therapy before pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension

Treatment and management of chronic thromboembolic pulmonary hypertension (CTEPH): A global cross-sectional scientific survey (CLARITY)

Advances in the treatment of chronic thromboembolic pulmonary hypertension (CTEPH) over the past decade changed the disease landscape, yet global insight on clinical practices remains limited. The CTEPH global cross-sectional scientific survey (CLARITY) aimed to gather information on the current diagnosis, treatment, and management of CTEPH and to identify unmet medical needs. This paper focuses on the treatment and management of CTEPH patients. The survey was circulated to hospital-based medical specialists through Scientific Societies and other medical organizations from September 2021 to May 2022. The majority of the 212 respondents involved in the treatment of CTEPH were from centers performing up to 50 pulmonary endarterectomy (PEA) and/or balloon pulmonary angioplasty (BPA) procedures per year. Variation was observed in the reported proportion of patients deemed eligible for PEA/BPA, as well as those that underwent the procedures, including multimodal treatment and subsequent follow-up practices. Prescription of pulmonary arterial hypertension-specific therapy was reported for a variable proportion of patients in the preoperative setting and in most nonoperable patients. Reported use of vitamin K antagonists and direct oral anticoagulants was similar (86% vs. 82%) but driven by different factors. This study presents heterogeneity in treatment approaches for CTEPH, which may be attributed to center-specific experience and region-specific barriers to care, highlighting the need for new clinical and cohort studies, comprehensive clinical guidelines, and continued education.

Comparison of different treatment strategies in patients with chronic thromboembolic pulmonary hypertension: a single centre real-world experience

BACKGROUND

Pulmonary endarterectomy (PEA) has been the most effective therapy for chronic thromboembolic pulmonary hypertension (CTEPH). However, there is a substantial proportion of patients deemed not operable in whom other treatment strategies are available: medical therapy and balloon pulmonary angioplasty (BPA). We aimed to compare different CTEPH treatment strategies effect in a real-world setting.

METHODS

All patients with CTEPH referred to our centre were included. We compare the short-term clinical, functional, exercise and haemodynamic effect of medical therapy (irrespective of subsequent treatment strategies), PEA and BPA (irrespective of previous/subsequent treatment strategies); we also describe the long-term outcome of the different patient groups.

RESULTS

We included 467 patients (39% were treated only with medical therapy, 43% underwent PEA, 13% underwent BPA and 5% were not treated with any therapy). Patients treated only with medical therapy were the oldest; compared to patients undergoing PEA, they had a lower exercise capacity, a higher risk profile and gained a lower haemodynamic, functional and survival benefit from the treatment. Patients undergoing BPA had a lower haemodynamic improvement but a comparable functional, exercise and risk improvement and a similar survival compared to patients undergoing PEA; their survival is anyway better than patients undergoing only medical treatment. Untreated historical control patients had the worst survival.

CONCLUSIONS

We confirm the superiority of PEA compared to any alternative treatment in CTEPH patients and we observe that BPA, in patients deemed not operable or with persistent/recurrent PH after PEA, leads to a better outcome than medical therapy alone.

[Chronic thromboembolic pulmonary hypertension]

Chronic thromboembolic pulmonary disease (CTEPD) is an important late complication of acute pulmonary embolism, in which the thrombi transform into fibrous tissue, become integrated into the vessel wall, and lead to chronic obstructions. CTEPD is differentiated into cases without pulmonary hypertension (PH), characterized by a mean pulmonary arterial pressure up to 20 mmHg and a form with PH. Then, it is still referred to as chronic thromboembolic pulmonary hypertension (CTEPH).When there is suspicion of CTEPH, initial diagnostic tests should include echocardiography and ventilation/perfusion scan to detect perfusion defects. Subsequently, referral to a CTEPH center is recommended, where further imaging diagnostics and right heart catheterization are performed to determine the appropriate treatment.Currently, three treatment modalities are available. The treatment of choice is pulmonary endarterectomy (PEA). For non-operable patients or patients with residual PH after PEA, PH-targeted medical therapy, and the interventional procedure of balloon pulmonary angioplasty (BPA) are available. Increasingly, PEA, BPA, and pharmacological therapy are combined in multimodal concepts.Patients require post-treatment follow-up, preferably at (CTE)PH centers. These centers are required to perform a minimum number of PEA surgeries (50/year) and BPA interventions (100/year).

Pathophysiology and Treatment of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition in which an organic thrombus remains in the pulmonary artery (PA) even after receiving anticoagulation therapy for more than 3 months and is complicated by pulmonary hypertension (PH), leading to right-sided heart failure and death. CTEPH is a progressive pulmonary vascular disease with a poor prognosis if left untreated. The standard treatment for CTEPH is pulmonary endarterectomy (PEA), which is usually performed only in specialized centers. In recent years, balloon pulmonary angioplasty (BPA) and drug therapy for CTEPH have also shown good results. This review discusses the complex pathogenesis of CTEPH and presents the standard of care, PEA, as well as a new device called BPA, which is showing remarkable progress in efficacy and safety. Additionally, several drugs are now demonstrating established evidence of efficacy in treating CTEPH.

Chronic thromboembolic pulmonary hypertension: from pathogenesis to the choice of treatment tactics

Presents data on the pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH), which serve as a rationale for approaches to the choice of treatment. CTEPH usually begins with persistent obstruction of the large and/or medium pulmonary arteries by organized thrombi. Impaired lysis of thrombi may be associated with abnormal fibrinolysis, hematological or autoimmune diseases. The molecular processes underlying the lesions of small vessels are not fully understand. The degree of small-vessel disease has a significant impact on the severity of CTEPH and postoperative outcomes. The CTEPH treatment has evolved with the development of three directions pulmonary endarterectomy, balloon angioplasty of pulmonary arteries and the use of specific therapy used for pulmonary arterial hypertension. The paper demonstrates the possibilities of a multimodal approach in the treatment of this category of patients.

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.

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 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.

Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension: state-of-the-art 2020

Pulmonary endarterectomy is the treatment of choice for patients with operable chronic thromboembolic pulmonary hypertension (CTEPH) as it is potentially curative. In expert centers that conduct > 50 pulmonary endarterectomy procedures per year, peri- and post-surgical mortality rates are very low and long-term outcomes are excellent, with three-year post-operative survival of > 80%. Therapeutic decisions in CTEPH are based largely on the location of the arterial obstruction, with pulmonary endarterectomy for obstructions in main, lobar, and segmental vessels, and balloon pulmonary angioplasty and medical therapy for small-vessel disease. Medical therapy is also an option for patients with persistent/recurrent pulmonary hypertension after pulmonary endarterectomy or balloon pulmonary angioplasty. With increasing surgical experience and improvements in instruments and procedures, an increasing number of patients are now considered operable who would previously have been inoperable, including some patients with subsegmental disease. At our University (University of California San Diego), around 200 pulmonary endarterectomy procedures are performed every year and several advances have been developed, including resection of more distal disease, availability of pulmonary endarterectomy to patients previously considered to be at too high risk for surgery, improved management of post-pulmonary endarterectomy complications, and minimally invasive pulmonary endarterectomy. Pulmonary endarterectomy can be combined with other treatment modalities, including balloon pulmonary angioplasty, medical therapy for persistent/recurrent pulmonary hypertension after pulmonary endarterectomy, and medical therapy or balloon pulmonary angioplasty as bridging therapy before surgery. Data on these combinations are, however, limited. Combination treatment should therefore be considered on an individual patient basis. In the future, however, multimodal therapy with pulmonary endarterectomy, balloon pulmonary angioplasty, and/or medical therapy is likely to be an important treatment option for many patients.

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.

Advances in targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by unresolved thrombi in the pulmonary arteries and microvasculopathy in nonoccluded areas. If left untreated, progressive pulmonary hypertension will induce right heart failure and, finally, death. Currently, pulmonary endarterectomy (PEA) remains the only method that has the potential to cure CTEPH. Unfortunately, up to 40% of patients are ineligible for this procedure for various reasons. In recent years, refined balloon pulmonary angioplasty (BPA) has become an alternative option for inoperable CTEPH patients, and it may be another curative treatment in the future, particularly in combination with prior PEA. Nevertheless, 23% of patients still suffer from persistent PH after BPA. Given that CTEPH shares many similarities with idiopathic pulmonary arterial hypertension (PAH), targeted drugs developed for PAH are also attractive options for CTEPH, especially for inoperable or persistent/recurrent CTEPH patients. To date, riociguat, macitentan, and subcutaneous treprostinil are the only drugs proven by randomized control trials to be capable of improving the exercise capacity (6-min walking distance) of CTEPH patients. In this review, we summarize the achievements and unresolved problems of PAH-targeted therapy for CTEPH over the last decade.

Pulmonary vasodilation in acute pulmonary embolism - a systematic review

Acute pulmonary embolism is the third most common cause of cardiovascular death. Pulmonary embolism increases right ventricular afterload, which causes right ventricular failure, circulatory collapse and death. Most treatments focus on removal of the mechanical obstruction caused by the embolism, but pulmonary vasoconstriction is a significant contributor to the increased right ventricular afterload and is often left untreated. Pulmonary thromboembolism causes mechanical obstruction of the pulmonary vasculature coupled with a complex interaction between humoral factors from the activated platelets, endothelial effects, reflexes and hypoxia to cause pulmonary vasoconstriction that worsens right ventricular afterload. Vasoconstrictors include serotonin, thromboxane, prostaglandins and endothelins, counterbalanced by vasodilators such as nitric oxide and prostacyclins. Exogenous administration of pulmonary vasodilators in acute pulmonary embolism seems attractive but all come with a risk of systemic vasodilation or worsening of pulmonary ventilation-perfusion mismatch. In animal models of acute pulmonary embolism, modulators of the nitric oxide-cyclic guanosine monophosphate-protein kinase G pathway, endothelin pathway and prostaglandin pathway have been investigated. But only a small number of clinical case reports and prospective clinical trials exist. The aim of this review is to give an overview of the causes of pulmonary embolism-induced pulmonary vasoconstriction and of experimental and human investigations of pulmonary vasodilation in acute pulmonary embolism.

Factors predicting outcome after pulmonary endarterectomy

Objective

Few studies have reported predictive factors of outcome after pulmonary endarterectomy (PEA) in chronic thromboembolic pulmonary hypertension. The purpose of this study was to determine factors influencing mortality and predictors of hemodynamic improvement after PEA.

Methods

A total of 383 consecutive patients who underwent PEA between January 2005 and December 2009 were retrospectively reviewed. Among them, 150 were fully reevaluated 7.5±1 months after PEA by NYHA class, 6–minute walk distance (6MWD), percentage of predicted carbon monoxide transfer factor (TL_CO) and right heart catheterisation.

Results

Mortality rates at 1 month, 1 year and 3 years were 2.8%, 6.9% and 7.5%, respectively. Preoperative pulmonary vascular resistance (PVR) independently predicted 1-month, 1- and 3-year mortality and age predicted mortality at 1 year and 3 years. Significant improvement in NYHA class and 6MWD were observed and PVR decreased from 773±353 to 307±221 dyn.sec.cm^-5 (p<0.001). In 96 patients (64%), PVR decreased by at least 50% and/or was reduced to lower than 250 dyn.sec.cm^-5. Preoperative cardiac output (CO) and TL_CO predicted hemodynamic improvement.

Conclusion

PEA is associated with an excellent long-term survival and a marked improvement in clinical status and hemodynamics. Some preoperative factors including PVR, CO and TL_CO can predict postoperative outcomes.

The changing landscape of chronic thromboembolic pulmonary hypertension management

For patients with chronic thromboembolic pulmonary hypertension (CTEPH), the current standard of care involves surgical removal of fibro-thrombotic obstructions by pulmonary endarterectomy. While this approach has excellent outcomes, significant proportions of patients are not eligible for surgery or suffer from persistent/recurrent pulmonary hypertension after the procedure. The availability of balloon pulmonary angioplasty and the approval of the first medical therapy for use in CTEPH have significantly improved the outlook for patients ineligible for pulmonary endarterectomy. In this comprehensive review, we discuss the latest developments in the rapidly evolving field of CTEPH. These include improvements in imaging modalities and advances in surgical and interventional techniques, which have broadened the range of patients who may benefit from such procedures. The efficacy and safety of targeted medical therapies in CTEPH patients are also discussed, particularly the encouraging data from the recent MERIT-1 trial, which demonstrated the beneficial impact of using macitentan to treat patients with inoperable CTEPH, including those on background therapy. As the treatment options for CTEPH improve, hybrid management involving more than one intervention in the same patient may become a viable option in the near future.

Management of CTEPH is evolving rapidly, leading to improved patient outcomeshttp://ow.ly/rHrt30gUQWX

Treatment of Chronic Thromboembolic Pulmonary Hypertension: The Role of Medical Therapy and Balloon Pulmonary Angioplasty

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potentially curable disease when treated with pulmonary thromboendarterectomy (PTE). However, even at experienced surgical centers, nearly one-third of patients with CTEPH will be deemed inoperable for reasons including distal disease, comorbidities, or out-of-proportion pulmonary hypertension. It is in these patients with inoperable CTEPH that pulmonary hypertension (PH)-targeted medical therapy and balloon pulmonary angioplasty have potential therapeutic value. Previous unblinded cohort trials have assessed PH-targeted medical therapy in various subpopulations of CTEPH patients using epoprostenol, treprostinil, sildenafil, bosentan, and iloprost, each demonstrating measurable pulmonary hemodynamic effects. However, riociguat, a soluble guanylate cyclase stimulator, is the first FDA-approved therapy for inoperable CTEPH to demonstrate both an improvement in functional capabilities (6-minute walk time) as well as significant gains in secondary pulmonary hemodynamic end points in a large placebo-controlled trial. Balloon pulmonary angioplasty is an interventional procedure using telescoping catheters placed in the pulmonary arteries, through which wires and balloons are used to mechanically disrupt chronic clot material and relieve pulmonary vascular obstruction. Contemporary case series from multiple centers worldwide have demonstrated pulmonary hemodynamic improvement with this approach. As a result of these advances, patients with inoperable CTEPH who had few options as recently as 5 years ago now have alternatives with emerging evidence of therapeutic efficacy.

Medical management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) results from incomplete resolution of acute pulmonary emboli, organised into fibrotic material that obstructs large pulmonary arteries, and distal small-vessel arteriopathy. Pulmonary endarterectomy (PEA) is the treatment of choice for eligible patients with CTEPH; in expert centres, PEA has low in-hospital mortality rates and excellent long-term survival. Supportive medical therapy consists of lifelong anticoagulation plus diuretics and oxygen, as needed.

An important recent advance in medical therapy for CTEPH is the arrival of medical therapies for patients with inoperable disease or persistent/recurrent pulmonary hypertension after PEA. The soluble guanylate cyclase stimulator riociguat is licensed for the treatment of CTEPH in patients with inoperable disease or with recurrent/persistent pulmonary hypertension after PEA. Clinical trials of this agent have shown improvements in patients' haemodynamics and exercise capacity. Phosphodiesterase-5 inhibitors, endothelin receptor antagonists and prostanoids have been used in the treatment of CTEPH, but evidence of benefit is limited. Challenges in the future development of medical therapy for CTEPH include better understanding of the underlying pathology, end-points to monitor the condition's progress, and the optimisation of pulmonary arterial hypertension therapies in relation to diverse patient characteristics and emerging options such as balloon pulmonary angioplasty.

An Update on the Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary artery hypertension that is defined as a mean arterial pulmonary pressure greater than 25mmHg that persists for more than 6 months following anticoagulation therapy in the setting of pulmonary emboli. CTEPH is categorized by the World Health Organization as group IV pulmonary hypertension and is thought to be due to unresolved thromboemboli in the pulmonary artery circulation. Among the 5 classes of pulmonary hypertension, CTEPH is unique in that it is potentially curable with the use of pulmonary thromboendarterectomy surgery. Despite an increasing array of medical and surgical treatment options for patients with CTEPH over the past 2 decades, patients commonly present with advanced disease and carry a poor prognosis, thus, the need for early diagnosis and appropriate referral to an expert center. This review article first highlights the epidemiology, pathophysiology, and clinical presentation of CTEPH. The article then provides diagnostic and therapeutic algorithms for the management of the patient with suspected CTEPH.

Exercise physiological responses to drug treatments in chronic thromboembolic pulmonary hypertension

We tested the hypothesis that patients with chronic thromboembolic pulmonary hypertension (CTEPH) that was deemed to be inoperable were more likely to respond to drugs for treating pulmonary arterial hypertension (PAH) by using cardiopulmonary exercise (CPX) testing than those with CTEPH that was deemed to be operable. We analyzed CPX testing data of all patients with CTEPH who were treated with PAH drugs and had undergone CPX testing before and after treatment at a single pulmonary hypertension center between February 2009 and March 2013. Suitability for pulmonary endarterectomy (PEA) was decided by experts in PEA who were associated with a treatment center. The group with inoperable CTEPH included 16 patients, the operable group included 26 patients. There were no differences in demographics and baseline hemodynamic data between the groups. Unlike patients in the operable group, after drug treatment patients with inoperable CTEPH had a significantly higher peak V̇o2 (P < 0.001), work load (P = 0.002), and oxygen pulse (P < 0.001). In terms of gas exchange, there was an overall net trend toward improved V̇e/V̇co2 in the group with inoperable CTEPH, with an increased PaCO2 (P = 0.01), suggesting reduced hyperventilation. No changes were observed in patients with operable CTEPH. In conclusion, treatment with PAH drug therapy reveals important pathophysiological differences between inoperable and operable CTEPH, with significant pulmonary vascular and cardiac responses in inoperable disease. Drug effects on exercise function observed in inoperable CTEPH cannot be translated to all forms of CTEPH.

Pharmacological therapy for patients with chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening disease resulting from unresolved thromboembolic obstructions. Pulmonary endarterectomy (PEA) surgery is the gold-standard treatment as it is potentially curative; however, not all patients are deemed operable and up to one-third have persistent or recurrent CTEPH after the procedure. Pulmonary arterial hypertension (PAH) and CTEPH have similar clinical presentations and histopathological features, so agents shown to be effective in PAH have often been prescribed to patients with CTEPH in the absence of proven therapies. However, clinical evidence for this strategy is not compelling. A number of small uncontrolled trials have investigated endothelin receptor antagonists, prostacyclin analogues and phosphodiesterase type 5 inhibitors in CTEPH with mixed results, and a phase III study of the endothelin receptor antagonist bosentan met only one of its two co-primary end-points. Recently, however, the soluble guanylate cyclase stimulator, riociguat, was approved in the USA and Europe for the treatment of inoperable or persistent/recurrent CTEPH following positive results from the phase III CHEST study (Chronic Thromboembolic Pulmonary Hypertension Soluble Guanylate Cyclase–Stimulator Trial). This article reviews the current evidence for the use of pharmacological therapies in CTEPH.

A review of pharmacological treatment of inoperable or persistent/recurrent CTEPH and the future standard of carehttp://ow.ly/KMUQV

Long-Term Outcome of Patients With Chronic Thromboembolic Pulmonary Hypertension: Results From an International Prospective Registry

BACKGROUND

Chronic thromboembolic pulmonary hypertension, a rare complication of acute pulmonary embolism, is characterized by fibrothrombotic obstructions of large pulmonary arteries combined with small-vessel arteriopathy. It can be cured by pulmonary endarterectomy, and can be clinically improved by medical therapy in inoperable patients. A European registry was set up in 27 centers to evaluate long-term outcome and outcome correlates in 2 distinct populations of operated and not-operated patients who have chronic thromboembolic pulmonary hypertension.

METHODS AND RESULTS

A total of 679 patients newly diagnosed with chronic thromboembolic pulmonary hypertension were prospectively included over a 24-month period. Estimated survival at 1, 2, and 3 years was 93% (95% confidence interval [CI], 90-95), 91% (95% CI, 87-93), and 89% (95% CI, 86-92) in operated patients (n=404), and only 88% (95% CI, 83-91), 79% (95% CI, 74-83), and 70% (95% CI, 64-76) in not-operated patients (n=275). In both operated and not-operated patients, pulmonary arterial hypertension-targeted therapy did not affect survival estimates significantly. Mortality was associated with New York Heart Association functional class IV (hazard ratio [HR], 4.16; 95% CI, 1.49-11.62; P=0.0065 and HR, 4.76; 95% CI, 1.76-12.88; P=0.0021), increased right atrial pressure (HR, 1.34; 95% CI, 0.95-1.90; P=0.0992 and HR, 1.50; 95% CI, 1.20-1.88; P=0.0004), and a history of cancer (HR, 3.02; 95% CI, 1.36-6.69; P=0.0065 and HR, 2.15; 95% CI, 1.18-3.94; P=0.0129) in operated and not-operated patients, respectively. Additional correlates of mortality were bridging therapy with pulmonary arterial hypertension-targeted drugs, postoperative pulmonary hypertension, surgical complications, and additional cardiac procedures in operated patients, and comorbidities such as coronary disease, left heart failure, and chronic obstructive pulmonary disease in not-operated patients.

CONCLUSIONS

The long-term prognosis of operated patients currently is excellent and better than the outcome of not-operated patients.

Chronic thromboembolic pulmonary hypertension: evolution in management

PURPOSE OF REVIEW

Chronic thromboembolic pulmonary hypertension (CTEPH) is an important cause of pulmonary hypertension. Although surgery is potentially curative, some patients present with inoperable disease. In these patients, medical therapies for pulmonary arterial hypertension are increasingly being used.

RECENT FINDINGS

The pathobiology of CTEPH development remains incompletely understood; however, evidence supports both large and small vessel disorder in patients with the disease. Surgical thromboendarterectomy is an increasingly well tolerated and often curative procedure and is the management strategy of choice for most patients. Although excellent outcomes in surgical management have been noted, the role of medical management in selected patients with inoperable or recurrent or persistent disease after surgery is increasing. A recent large, randomized controlled clinical trial of riociguat in CTEPH demonstrated improvements in exercise capacity, functional class, and hemodynamics. A safe, effective angioplasty approach to CTEPH is being pursued in addition.

SUMMARY

The approach to CTEPH management in the operable patient remains surgical, without clear benefit to preoperative pulmonary arterial hypertension-specific therapy at this time. Patients with inoperable disease or pulmonary hypertension following thromboendarterectomy, however, should be considered for medical management, with riociguat currently having the strongest evidence specific to CTEPH.

Perspectives on oral pulmonary hypertension therapies recently approved by the U.S. Food and Drug Administration

In the past 18 months, the U.S. Food and Drug Administration approved macitentan, riociguat, and treprostinil as oral agents for the treatment of pulmonary arterial hypertension (PAH); riociguat also became the first agent approved for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH). These new agents are welcome additional therapeutic options for PAH and CTEPH. However, their use can be complicated by potential drug interactions, adverse effects, dosing complexity, and cost. Macitentan, the newest endothelin receptor antagonist, showed significant benefits in a long-term event-driven trial of morbidity and mortality. Dosed once daily and with minimal liver toxicity, it has potential drug interactions with potent CYP 3A4 inhibitors and inducers, and can decrease hemoglobin levels. Riociguat is approved for PAH and clinically inoperable CTEPH to improve exercise capacity and functional status. Riociguat requires dose titration beginning with 1 mg up to 2.5 mg three times a day, as tolerated, and should be used with caution in patients with underlying risk factors for systemic hypotension. Oral treprostinil, approved to improve exercise capacity in PAH, is associated with gastrointestinal side effects and headaches that are often dose limiting. Doses can begin with 0.125 mg or 0.25 mg twice a day with gradual increases on up to a weekly basis, as tolerated. Thrice daily dosing and administration with a meal can improve tolerance. These newer agents represent advances, but their specific roles in relation to pre-existing therapies are undergoing further evaluation. Therefore, close collaboration with clinicians at centers with therapeutic expertise is highly recommended to optimize patient outcomes.

Developments in pulmonary arterial hypertension-targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease characterised by the presence of organised chronic thromboembolic material occluding the proximal pulmonary arteries and a vasculopathy in the distal pulmonary arterial tree. Pulmonary endarterectomy (PEA) is a potential cure for many patients with CTEPH. However, PEA is not suitable for patients with a significant distal distribution of chronic thromboembolic material or with significant comorbidities. Also, a proportion of patients are left with residual CTEPH post PEA. Until recently, pulmonary arterial hypertension-targeted therapies have been used off licence to treat patients with inoperable or residual CTEPH. The CHEST1 study investigated the use of riociguat and was the first randomised controlled trial to show efficacy in inoperable or residual CTEPH. In this review, we explore the pathophysiology of CTEPH and review the current trial evidence for pulmonary arterial hypertension-targeted therapies. We also include a discussion of physiological considerations that require further investigation.

Chronic thromboembolic pulmonary hypertension: the evolving treatment landscape

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension (PH) arising from the obstruction of pulmonary arterial vessels by organised thromboembolic material [1]. Much like other forms of PH, CTEPH has historically proven to be a challenging clinical entity in that it is frequently underdiagnosed and undertreated [1–3]. This lack of clinical recognition can result in patients with CTEPH experiencing progressive PH and eventual right ventricular failure [1, 4].

PEA is the treatment of choice for operable CTEPH. Riociguat is the first medical therapy for inoperable CTEPH http://ow.ly/LXTZ0

[Surgical treatment of chronic thromboembolic pulmonary hypertension]

Chronic thromboembolic pulmonary hypertension is a rare but underdiagnosed disease. The development of imaging played a crucial role for the screening and the decision of operability over the past few years. Indeed, chronic thromboembolic pulmonary hypertension is the only type of pulmonary hypertension with a potential curative treatment: pulmonary endarterectomy. It is a complexe surgical procedure performed under cardiopulmonary bypass with deep hypothermia and circulatory arrest. The aim of the procedure is to completely remove the scar tissue inside the pulmonary arteries down to the segmental and sub-segmental levels. Compared to lung transplantation, which carries a postoperative mortality of 15-20% and a 5-year survival of 50%, pulmonary endarterectomy is a curative treatment with a postoperative mortality of less than 3%. However, lung transplantation remains an option for young patients with inoperable distal disease or after pulmonary endarterectomy failure. Considering that medical history of deep venous thrombosis or pulmonary embolism is lacking in 25 to 50%, the diagnosis of chronic thromboembolic pulmonary hypertension remains challenging. The lung V/Q scan is useful for the diagnosis showing ventilation and perfusion mismatches. Lesions located at the level of the pulmonary artery, the lobar or segmental arteries may be accessible to surgical removal. The pulmonary angiogram with the lateral view and the pulmonary CT scan help to determine the level of the intravascular lesions. If there is a correlation between the vascular obstruction assessed by imaging and the pulmonary resistance, pulmonary endarterectomy carries a postoperative mortality of less than 3% and has a high rate of success. If the surgery is performed at a later stage of the disease, pulmonary arteriolitis developed mainly in unobstructed territories and participated in the elevated vascular resistance. At this stage, postoperative risk is higher.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Biomarkers in pulmonary arterial hypertension

The biomarker is an indicaror of a biological or pathological process.

Clinical observations, measures or environmental events, or measured laboratory values can all be biomarkers in the appropriate setting. An ideal biomarker reflects the underlying biological process, predicts clinical events, is easily obtainable, is reproducible and is not prohibitively expensive. This typically requires validation in longitudinal cohort studies. Biomarkers may help understand the pathological mechanisms responsible for the disease, help as screening tools, predict disease worsening or decline, and determine adequacy of response to therapeutic interventions.

Chronic thromboembolic pulmonary hypertension: Medical treatment

Chronic thromboembolic pulmonary hypertension (CTEPH) is responsible for significant levels of morbidity and mortality. The estimated cumulative incidence of CTEPH is 2-4% among patients presenting with acute pulmonary thromboembolism. Currently, at the time of CTEPH diagnosis, 37.9% of the patients in an international registry were receiving at least one pulmonary arterial hypertension (PAH)-targeted therapy. Advanced medical therapy is considered in patients with inoperable disease, as a bridge to pulmonary endarterectomy or in those with persistent or recurrent pulmonary hypertension. PAH-specific medical therapies include endothelin receptor antagonists, phosphodiesterase inhibitors, and prostacyclin analogues. The present article will focus on recent developments in the pharmacological treatment of CTEPH.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but debilitating and life-threatening complication of acute pulmonary embolism. CTEPH results from persistent obstruction of pulmonary arteries and progressive vascular remodelling. Not all patients presenting with CTEPH have a history of clinically overt pulmonary embolism. The diagnostic work-up to detect or rule out CTEPH should include ventilation-perfusion scintigraphy, which has high sensitivity and a negative predictive value of nearly 100%. CT angiography usually reveals typical features of CTEPH, including mosaic perfusion, part or complete occlusion of pulmonary arteries, and intraluminal bands and webs. Patients with suspected CTEPH should be referred to a specialist centre for right-heart catheterisation and pulmonary angiography. Surgical pulmonary endarterectomy remains the treatment of choice for CTEPH and is associated with excellent long-term results and a high probability of cure. For patients with inoperable CTEPH, various medical and interventional therapies are being developed.

Pulmonary Thromboendarterectomy for Chronic Thromboembolic Pulmonary Hypertension

Pulmonary thromboendarterectomy is the most effective therapy for chronic thromboembolic pulmonary hypertension. The pathophysiology, anesthetic management, and perioperative outcomes of patients with chronic thromboembolic pulmonary hypertension undergoing pulmonary thromboendarterectomy are reviewed.

Treprostinil for pulmonary hypertension

Treprostinil (Remodulin, United Therapeutics) is a stable, long-acting prostacyclin analog, which has been shown to improve clinical state, functional class, exercise capacity and quality of life in patients with pulmonary arterial hypertension, an uncommon disease with poor prognosis. The drug is administered as a continuous subcutaneous infusion using a portable miniature delivery system. Side effects include facial flush, headache, jaw pain, abdominal cramping and diarrhea. These are all typical of prostacyclin impregnation and manageable by symptom-directed dose adjustments. Infusion site pain, a more serious side effect, may limit the treatment in 10% of patients. Otherwise, treprostinil has an excellent safety profile and compares favorably with reference continuous intravenous epoprostenol (Flolan, GlaxoSmithKline) therapy. Treprostinil has a place in currently proposed treatment algorithms of pulmonary arterial hypertension.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a disease with high mortality and few treatment options. This article reviews the epidemiology of CTEPH and identifies risk factors for its development. The pathobiology and the progression from thromboembolic events to chronically increased right-sided pressures are discussed. The diagnosis and assessment of CTEPH requires several modalities and the role of these is detailed. The pre-operative evaluation assesses peri-operative risk and determines the likelihood of benefit from PTE. Pulmonary thromboendarterectomy (PTE) remains the treatment of choice in appropriate patients. Nonsurgical therapies for CTEPH may provide benefit in patients who cannot be offered surgery.

A case report of pulmonary thromboendarterectomy for chronic thromboembolism in a patient with protein C deficiency

The patient was a 41-year-old female with chronic thromboembolism. She was admitted to an affiliated hospital with exertional dyspnea, leg swelling, and hemoptysis, and she was treated medically with tissue plasminogen activator and warfarin therapy. When transferred to our hospital, she was oxygen-dependent with severe dyspnea. A pulmonary arteriogram showed occlusion and stenosis of the pulmonary arteries. Cardiac catheterization revealed marked pulmonary hypertension. The lung perfusion scintigram showedmultiple defects in the right and left lungs. Preoperative laboratory data showed a markedly decreased protein C antigen level. Magnetic resonance angiography showed that a myoma uteri compressed the pelvic vein and that she had deep vein occlusion of the left leg. After the administration of an epoprostenol infusion and the insertion of an inferior vena cava filter, she underwent an operation. Under deep hypothermia, the bilateral pulmonary artery was opened and an endarterectomy was performed during intermittent circulatory arrest. After surgery, her pulmonary vascular resistance was in the normal range. Her New York Heart Association functional classification changed from class IV to class I. She has been in good condition for 7 years since the surgery.

Riociguat for the treatment of chronic thromboembolic pulmonary hypertension

BACKGROUND

Riociguat, a member of a new class of compounds (soluble guanylate cyclase stimulators), has been shown in previous clinical studies to be beneficial in the treatment of chronic thromboembolic pulmonary hypertension.

METHODS

In this phase 3, multicenter, randomized, double-blind, placebo-controlled study, we randomly assigned 261 patients with inoperable chronic thromboembolic pulmonary hypertension or persistent or recurrent pulmonary hypertension after pulmonary endarterectomy to receive placebo or riociguat. The primary end point was the change from baseline to the end of week 16 in the distance walked in 6 minutes. Secondary end points included changes from baseline in pulmonary vascular resistance, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, World Health Organization (WHO) functional class, time to clinical worsening, Borg dyspnea score, quality-of-life variables, and safety.

RESULTS

By week 16, the 6-minute walk distance had increased by a mean of 39 m in the riociguat group, as compared with a mean decrease of 6 m in the placebo group (least-squares mean difference, 46 m; 95% confidence interval [CI], 25 to 67; P<0.001). Pulmonary vascular resistance decreased by 226 dyn·sec·cm(-5) in the riociguat group and increased by 23 dyn·sec·cm(-5) in the placebo group (least-squares mean difference, -246 dyn·sec·cm(-5); 95% CI, -303 to -190; P<0.001). Riociguat was also associated with significant improvements in the NT-proBNP level (P<0.001) and WHO functional class (P=0.003). The most common serious adverse events were right ventricular failure (in 3% of patients in each group) and syncope (in 2% of the riociguat group and in 3% of the placebo group).

CONCLUSIONS

Riociguat significantly improved exercise capacity and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension. (Funded by Bayer HealthCare; CHEST-1 and CHEST-2 ClinicalTrials.gov numbers, NCT00855465 and NCT00910429, respectively.)

Updating clinical endpoint definitions

The 6-Minute Walk Distance (6-MWD) has been the most utilized endpoint for judging the efficacy of pulmonary arterial hypertension (PAH) therapy in clinical trials conducted over the past two decades. Despite its simplicity, widespread use in recent trials and overall prognostic value, the 6-MWD has often been criticized over the past several years and pleas from several PAH experts have emerged from the literature to find alternative endpoints that would be more reliable in reflecting the pulmonary vascular resistance as well as cardiac status in PAH and their response to therapy. A meeting of PAH experts and representatives from regulatory agencies and pharmaceutical companies was convened in early 2012 to discuss the validity of current as well as emerging valuable endpoints. The current work represents the proceedings of the conference.

Chronic thromboembolic pulmonary hypertension (CTEPH): updated Recommendations of the Cologne Consensus Conference 2011

In the 2009 European Guidelines on the diagnosis and treatment of pulmonary hypertension (PH), one section covers aspects of pathophysiology, diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). The practical implementation of the guidelines for this disease is of crucial importance, because CTEPH is a subset of PH which can potentially be cured by pulmonary endarterectomy (PEA). Nowadays, CTEPH is commonly underdiagnosed and not properly managed. Any patient with unexplained PH should be evaluated for the presence of CTEPH, and a ventilation/perfusion (V/Q) lung scan is recommended as screening method of choice. If the V/Q scan or CT angiography reveals signs of CTEPH, the patient should be referred to a specialized center with expertise in the medical and surgical management of this disease. Every case has to be reviewed by an experienced PEA surgeon for the assessment of operability. In this updated recommendation, important contents of the European guidelines were commented, and more recent information regarding diagnosis and treatment was added.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potentially life-threatening condition characterized by obstruction of pulmonary arterial vasculature by acute or recurrent thromboemboli with subsequent organization, leading to progressive pulmonary hypertension and right heart failure. Until relatively recently, CTEPH was a diagnosis made primarily at autopsy, but advances made in diagnostic modalities and surgical pulmonary endarterectomy techniques have made this disease treatable and even potentially curable. Although published guidelines are available, in the absence of randomized controlled trials regarding CTEPH there is a lack of standardization, and treatment options have to be individualized.