A Multicenter, Single-Blind, Randomized, Warfarin-Controlled Trial of Edoxaban in Patients With Chronic Thromboembolic Pulmonary Hypertension: KABUKI Trial

Recent Advances in Chronic Thromboembolic Pulmonary Hypertension: Expanding the Disease Concept and Treatment Options

Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive form of pulmonary hypertension characterized by unresolved thromboembolic occlusion of pulmonary arteries, leading to increased pulmonary arterial pressure and right heart failure. This review examines recent advances in the pathophysiology, diagnosis, and management of CTEPH, focusing on expanding disease concepts and evolving therapeutic approaches. The incidence of CTEPH has been revised upward with improved diagnostic techniques revealing a higher prevalence than previously recognized. Advances in surgical and interventional therapies, particularly pulmonary endarterectomy and balloon pulmonary angioplasty, have significantly improved outcomes. Emerging medical therapies, including pulmonary vasodilators like riociguat, have offered new hope for inoperable cases. The understanding of CTEPH has broadened, leading to better diagnostic strategies and more comprehensive treatment options that significantly enhance patient outcomes. Multidisciplinary team approaches are crucial in managing the disease effectively.

An overview of balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe and progressive condition caused by unresolved pulmonary arterial obstructions, leading to secondary microvasculopathy and poor hemodynamics. Pulmonary endarterectomy (PEA) is the first-line treatment for operable patients. Balloon pulmonary angioplasty (BPA) has emerged as a promising treatment option for patients considered inoperable due to distal lesions, comorbidities, or residual pulmonary hypertension (PH) after PEA. Following the development of the BPA in safety and efficacy, it has been widely adopted and utilized across the globe.

AREAS COVERED

This review covers the historical development of BPA, its clinical role, and technical methodologies. Medical therapies as an adjunctive role in CTEPH management are also discussed. Finally, we present recent BPA experiences from our institution, highlighting hemodynamic outcomes and survival rates.

EXPERT OPINION

BPA is a transformative treatment for patients with CTEPH, particularly those ineligible for PEA. Procedural refinements have significantly improved safety and efficacy. However, challenges remain, including the standardization of decision-making processes for management and the establishment of optimal treatment goals. Ongoing research continues to refine the role of BPA to improve outcomes and enhance the quality of life for patients with CTEPH. [Figure: see text].

Milestones in therapeutic and antithrombotic strategies for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition caused by persistent thrombus obstructing the pulmonary arteries, resulting in pulmonary hypertension. Pulmonary endarterectomy remains the gold standard treatment and can provide dramatic improvement in eligible patients. However, approximately 40 % of patients are inoperable. Over the past years, several randomized controlled trials have explored pulmonary vasodilators and balloon pulmonary angioplasty. Based on these trials, a multimodal treatment approach has been established. Balloon pulmonary angioplasty has shown hemodynamic improvement rather than pulmonary vasodilators in randomized controlled trials. Similarly, lifelong anticoagulation therapy is the cornerstone of CTEPH management. While vitamin K antagonists such as warfarin have been the standard recommended by CTEPH guidelines, recent studies, including the CTEPH AC Registry and the KABUKI trial, suggest that direct oral anticoagulants may be safe and effective alternatives. Several ongoing randomized controlled trials aim to refine treatment strategies. The IMPACT-CTEPH trial is investigating whether the initial combination therapy (riociguat + macitentan) is superior to monotherapy before balloon pulmonary angioplasty. The GO-CTEPH trial compares the efficacy of pulmonary endarterectomy and balloon pulmonary angioplasty in eligible patients. The THERAPY-HYBRID-BPA trial is evaluating the need for continued riociguat after balloon pulmonary angioplasty. The FIND-DCR study is evaluating a new imaging modality for the early detection of CTEPH. As research advances, multimodal approaches combining surgical, interventional, and pharmacological treatments are expected to improve patient outcomes and shape the future of CTEPH management.

Direct Oral Anticoagulants: Quick Primer on When to Use and When to Avoid

Direct oral anticoagulants (DOACs) have transformed the landscape of antithrombotic therapy in the past two decades. However, there is uncertainty about when they should or should not be used for treatment or prevention of thromboembolic events. DOACs have largely replaced warfarin for many patients with atrial fibrillation or venous thromboembolism who require anticoagulant therapy. In addition to noninferior efficacy, fewer drug-drug and food-drug interactions and improved convenience; DOACs have been shown to reduce the risk of intracranial hemorrhage. They have also received new indications compared with warfarin, such as cardiovascular risk reduction in patients with stable atherosclerotic diseases. However, there are some scenarios in which DOACs are associated with inferior efficacy or worse safety compared with standard treatment, such as warfarin. These include patients with mechanical heart valves, thrombotic antiphospholipid syndrome, and others. Although DOACs offer a streamlined and convenient option for the management of many patients with or at risk of thromboembolic events, their use should be avoided in certain high-risk scenarios. This minireview summarizes such conditions and those in which there is uncertainty for use of DOACs for particular diseases or particular patient subgroups.

Tailoring oral anticoagulant treatment in the era of multi-drug therapies for PAH and CTEPH

The use of oral anticoagulants in the management of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) presents distinct therapeutic challenges and benefits. In PAH, the benefits of oral anticoagulation are uncertain, with studies yielding mixed results on their efficacy and safety. Conversely, oral anticoagulants are a cornerstone in the treatment of CTEPH, where their use is consistently recommended to prevent recurrent thromboembolic events. The choice between vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) remains a significant clinical question, as each type presents advantages and potential drawbacks. Furthermore, drug-drug interactions (DDIs) with concomitant PAH and CTEPH treatments complicate anticoagulant management, necessitating careful consideration of individual patient regimens. This review examines the current evidence on oral anticoagulant use in PAH and CTEPH and discusses the implications of DDIs within a context of multi-drug treatments, including targeted drugs in PAH.

Monitoring anti-factor Xa activity in patients with chronic thromboembolic pulmonary hypertension treated with factor Xa inhibitors

Direct oral anticoagulants (DOACs) have been used clinically in patients with chronic thromboembolic pulmonary hypertension (CTEPH) for secondary prevention after acute venous thromboembolism, although the data are limited. We evaluated the effects of DOACs-especially factor Xa (FXa) inhibitors-by measuring anti-factor Xa activity (AXA). Fifty consecutive CTEPH patients treated with rivaroxaban, apixaban, or edoxaban were enrolled. Heparin-calibrated AXA was measured at peak and trough. The median peak heparin-calibrated AXA across all 50 patients was 1.90 IU/mL and was comparable among the three FXa inhibitors. At trough, heparin-calibrated AXA was significantly higher in apixaban-treated patients (median 0.70 IU/mL) than in those given rivaroxaban (median 0.11 IU/mL) or edoxaban (median 0.11 IU/mL, p < 0.001). Peak heparin-calibrated AXA was significantly lower with reduced-dosage FXa inhibitor (edoxaban 30 mg/day) than with the reference dosage (edoxaban 60 mg/day, apixaban 10 mg/day, or rivaroxaban 15 mg/day, p = 0.01). The heparin-calibrated AXA of both rivaroxaban and apixaban was strongly significantly correlated with the plasma concentration of each drug. The cumulative rate of major and clinically relevant non-major bleeding was significantly higher in patients with peak heparin-calibrated AXA ≥ 2.09 IU/mL. Heparin-calibrated AXA could provide useful information for treating CTEPH patients with FXa inhibitors.

Chronic thromboembolic pulmonary disease

Chronic thromboembolic pulmonary hypertension is a complication of pulmonary embolism and a treatable cause of pulmonary hypertension. The pathology is a unique combination of mechanical obstruction due to failure of clot resolution, and a variable degree of microvascular disease, that both contribute to pulmonary vascular resistance. Accordingly, multiple treatments have been developed to target the disease components. However, accurate diagnosis is often delayed. Evaluation includes high-quality imaging modalities, necessary for disease confirmation and for appropriate treatment planning. All patients with chronic thromboembolic pulmonary disease, and especially those with pulmonary hypertension, should be referred to expert centres for multidisciplinary team decision on treatment. The first decision remains assessment of operability, and the best improvement in symptoms and survival is achieved by the mechanical therapies, pulmonary endarterectomy and balloon pulmonary angioplasty. With the advances in multimodal therapies, excellent outcomes can be achieved with 3-year survival of >90%.

The use of non-vitamin K antagonist oral anticoagulants in chronic thromboembolic pulmonary hypertension: an updated meta-analysis

Studies have demonstrated the beneficial effects of non-vitamin K antagonist oral anticoagulants (NOACs) for the treatment of atrial fibrillation and venous thromboembolism (VTE). The impact of NOACs on chronic thromboembolic pulmonary hypertension (CTEPH) remains controversial. This meta-analysis was conducted to investigate the effectiveness and safety of NOACs compared with vitamin K antagonists (VKAs) in patients with CTEPH. A comprehensive search of PubMed, Embase, and Cochrane Library was conducted for relevant studies, encompassing data from inception until November 2023. The data were pooled using a fixed-effects model if the I2 value was less than 50%; otherwise, a random-effects model was employed. Overall, two randomized controlled trials (RCTs) and eight observational studies involving 4556 patients with CTEPH were included. Patients receiving NOACs exhibited a significantly lower incidence of all-cause mortality (odds ratio [OR] = 0.52, 95% confidence interval [CI]: 0.36-0.76) and major bleeding (OR = 0.58, 95% CI: 0.36-0.92) compared to those with VKAs. There were no significant differences in the rate of VTE recurrence (OR = 1.07, 95% CI: 0.72-1.59), total bleeding (OR = 0.78, 95% CI: 0.60-1.01), and minor bleeding (OR = 1.11, 95% CI: 0.73-1.69) between the two studied groups. Similar results were found in the subgroup analysis and sensitivity analysis.This meta-analysis provided evidence that NOACs could be superior to VKAs for the treatment of CTEPH. NOACs might be safe and a convenient alternative to VKAs for thromboprophylaxis in patients with CTEPH.

Beyond Anticoagulation: A Comprehensive Review of Non-Vitamin K Oral Anticoagulants (NOACs) in Inflammation and Protease-Activated Receptor Signaling

Non-vitamin K oral anticoagulants (NOACs) have revolutionized anticoagulant therapy, offering improved safety and efficacy over traditional agents like warfarin. This review comprehensively examines the dual roles of NOACs-apixaban, rivaroxaban, edoxaban, and dabigatran-not only as anticoagulants, but also as modulators of inflammation via protease-activated receptor (PAR) signaling. We highlight the unique pharmacotherapeutic properties of each NOAC, supported by key clinical trials demonstrating their effectiveness in preventing thromboembolic events. Beyond their established anticoagulant roles, emerging research suggests that NOACs influence inflammation through PAR signaling pathways, implicating factors such as factor Xa (FXa) and thrombin in the modulation of inflammatory responses. This review synthesizes current evidence on the anti-inflammatory potential of NOACs, exploring their impact on inflammatory markers and conditions like atherosclerosis and diabetes. By delineating the mechanisms by which NOACs mediate anti-inflammatory effects, this work aims to expand their therapeutic utility, offering new perspectives for managing inflammatory diseases. Our findings underscore the broader clinical implications of NOACs, advocating for their consideration in therapeutic strategies aimed at addressing inflammation-related pathologies. This comprehensive synthesis not only enhances understanding of NOACs' multifaceted roles, but also paves the way for future research and clinical applications in inflammation and cardiovascular health.

Chronic Thromboembolic Pulmonary Hypertension: the therapeutic assessment

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a severe and complex condition that evolves from unresolved pulmonary embolism, leading to fibrotic obstruction of pulmonary arteries, pulmonary hypertension, and potential right heart failure. The cornerstone of CTEPH management lies in a multifaceted therapeutic approach tailored to individual patient profiles, reflecting the disease's heterogeneity. This review delves into the current therapeutic strategies for CTEPH, including surgical pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA), and targeted pharmacological treatments such as PDE5 inhibitors, endothelin receptor antagonists, sGC stimulators, and prostanoids. Lifelong anticoagulation is also highlighted as a preventive strategy against recurrent thromboembolism. Special emphasis is placed on the interdisciplinary nature of CTEPH care, necessitating collaboration among PEA surgeons, BPA interventionists, PH specialists, and thoracic radiologists to ensure comprehensive treatment planning and execution. The review underscores the importance of selecting an appropriate treatment modality based on the patient's specific disease characteristics and the evolving landscape of CTEPH treatment, aiming to improve patient outcomes through integrated care strategies.

Safety and Outcomes with Direct Oral Anticoagulants Versus Vitamin-K Antagonists in Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review, Meta-Analysis, and Meta-Regression

Chronic thromboembolic pulmonary hypertension (CTEPH) is a subtype of pulmonary hypertension characterized by organized thrombi inside the pulmonary vasculature, leading to an increase in pulmonary artery pressure. CTEPH is seen in about 3-4% of patients with acute pulmonary embolism and is associated with poor outcomes. Apart from surgical intervention, lifelong anticoagulation is the mainstay of CTEPH management. Traditionally, CTEPH is managed with vitamin-K antagonists (VKA); however, direct oral anticoagulants (DOACs) are recently gaining popularity. However, the current literature comparing DOACs versus VKAs in CTEPH has inconsistent results. An electronic search of the major bibliographic databases was performed to retrieve studies comparing DOACs versus VKAs in CTEPH patients. For dichotomous outcomes, the odds ratio (ORs) with 95% confidence intervals (CI) were pooled using the DerSimonian and Laird random-effects model to generate forest plots. Statistical significance was considered at P < 0.05. Ten studies were included with 3936 patients (1269 in the DOAC group and 2667 in the VKA group). Treatment with DOAC was associated with no statistically significant difference in the risk of all-cause mortality (OR, 0.78; 95% CI, 0.35-1.71; P < 0.53), venous thromboembolism (OR, 1.19; 95% CI, 0.59-2.40; P = 0.63), major bleeding (OR, 0.68; 95% CI, 0.38-1.22; P = 0.20), and clinically relevant nonmajor bleeding (OR, 1.22; 95% CI, 0.80-1.86; P = 0.37). Our analysis demonstrates that DOACs are noninferior to VKAs in terms of their safety and outcomes profile in CTEPH. Further trials are needed to evaluate more robust evidence and to compare additional outcomes.

Chronic thromboembolic pulmonary hypertension and balloon pulmonary angioplasty - Where are we in 2024?

Pulmonary endarterectomy (PEA) is the first-line treatment for patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, some patients with CTEPH are considered inoperable, and in the last decade, balloon pulmonary angioplasty (BPA) has emerged as a viable therapeutic option for these patients with prohibitive surgical risk or recurrent pulmonary hypertension following PEA. Numerous international centers have increased their procedural volume of BPA and have reported improvements in pulmonary hemodynamics, patient functional class and right ventricular function. Randomized controlled trials have also demonstrated similar findings. Recent refinements in procedural technique, increased operator experience and advancements in procedural technology have facilitated marked reduction in the risk of complications following BPA. Current guidelines recommend BPA for patients with inoperable CTEPH and persistent pulmonary hypertension following PEA. The pulmonary arterial endothelium plays a vital role in the pathophysiologic development and progression of CTEPH.

Clinical outcomes between direct oral anticoagulants versus vitamin K antagonists in chronic thromboembolic pulmonary hypertension: A systematic review and meta-analysis

Pulmonary hypertension (PH) is a known chronic condition that can lead to increased morbidity and mortality. Patients who develop PH due to thromboembolic disease are catalogued as chronic thromboembolic pulmonary hypertension (CTEPH). Anticoagulation remains a topic of interest in these patients. PUBMED, EMBASE and COCHRANE databases were searched by two investigators until December 2023. Information was analyzed for all-cause mortality, venous thromboembolism and major bleeding. We included a total of 10 studies in this meta-analysis. Our pooled analysis demonstrated that DOACs were non-inferior in all-cause mortality [OR 0.88, 95 % CI (0.48, 1.61)], venous thromboembolism [OR 1.00, 95 % CI (0.50, 1.98)] and major bleeding [OR 0.78, 95 % CI (0.43, 1.40)] when compared to VKAs. In conclusion, our meta-analysis supports the use of DOACs in patients with CTEPH. Further randomized trials are still needed to confirm our results in terms of safety and mortality.

Direct Oral Anticoagulants in Chronic Thromboembolic Pulmonary Hypertension: First Meta-Analysis of Prospective Studies

Direct oral anticoagulants (DOACs) are becoming increasingly popular clinically, but their safety and effectiveness profile in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is not well-established. Literature from the PubMed and EMBASE databases was systematically screened up to February 2024 to identify relevant studies on the use of DOACs in CTEPH patients. The bias risk of RCTs was assessed using the Cochrane Risk of Bias Tool 2.0. The quality of observational prospective cohorts was assessed using the Newcastle-Ottawa Scale tool. Data pooled from different studies were analyzed. Results from 4 studies were gathered, including 2 randomized controlled trials and 2 prospective cohorts, with a total of 2038 patients, of which 751 were on DOACs and 1287 were on vitamin K antagonists (VKAs). Similar rates of all-cause mortality (3.33% vs 3.33%, RD = -0.01%, 95% CI [-0.02%, 0.00%], P = .17), VTE recurrence (1.46% vs 2.12%, RD = -0.00%, 95% CI [-0.01%, 0.01%], P = .92) were observed. DOACs were associated with a nonsignificant reduction in bleeding events including major bleeding (2.22% vs 3.71%, RD = -0.01%, 95% CI [-0.04%, 0.01%], P = .30), any bleeding (5.33% vs 9.94%, RD = -0.03%, 95% CI [-0.07%, 0.01%], P = .10), and minor bleeding (4.17% vs 13.3%, RD = -0.06%, 95% CI [-0.23%, 0.10%], P = .45). Data pooled from existing perspective trials suggests the use of DOACs in CTEPH patients as an effective and safe alternative to VKAs.