Evolution of patients with chronic thromboembolic pulmonary hypertension treated by balloon pulmonary angioplasty, according to their anticoagulant regimens

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.

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.

Anticoagulation in chronic thromboembolic pulmonary hypertension: A systematic review and meta-analysis

INTRODUCTION

Life-long anticoagulation is the recommended management for chronic thromboembolic pulmonary hypertension (CTEPH). Evidence regarding the use of direct oral anticoagulants (DOAC) for CTEPH is yet to be established. We performed a systematic review and meta-analysis to clarify the outcomes of CTEPH in patients who used DOAC or vitamin K antagonists (VKA).

METHODS

We reviewed literature in PubMed and EMBASE through March 2023. We included studies involving patients with CTEPH where DOAC and VKA were compared. We collected data including intervention history for CTEPH, bleeding events, recurrence of VTE (venous thromboembolism), and mortality. We performed a meta-analysis using the Mantel-Haenszel method with a fixed-effects model.

RESULTS

We included one randomized clinical trial and six observational studies, with a total of 2969 patients. Six studies investigated major bleeding outcomes, and seven investigated all bleeding outcomes. There were no differences in major bleeding (RR 0.59, 95 % CI [0.34-1.02], I2 = 0 %) and all-bleeding (RR 0.87, 95 % CI [0.67-1.13], I2 = 0 %). Based on the five studies we included, DOAC was associated with a lower risk of mortality (RR 0.54, 95 % CI: 0.37-0.79, I2 = 5 %). However, a higher risk of recurrent pulmonary embolism (PE) was seen in three studies (RR 3.80, 95 % CI: [1.93-7.50], I2 = 11 %). No significant differences were noted in terms of VTE.

CONCLUSION

DOAC compared to VKA was associated with a significantly lower mortality and higher risk of recurrent PE. Since most of the included studies are observational, we must consider the existence of multiple biases and confounding factors.

Efficacy and safety of edoxaban in patients with chronic thromboembolic pulmonary hypertension: protocol for a multicentre, randomised, warfarin-controlled, parallel group trial - KABUKI trial

Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of prior pulmonary thromboembolism (PE), caused by incomplete clot dissolution after PE. In patients with CTEPH, lifelong anticoagulation is mandatory to prevent recurrence of PE and secondary in situ thrombus formation. Warfarin, a vitamin K antagonist, is commonly used for anticoagulation in CTEPH based on historical experience and evidence. The anticoagulant activity of warfarin is affected by food and drug interactions, requiring regular monitoring of prothrombin time. The lability of anticoagulant effect often results in haemorrhagic and thromboembolic complications. Thus, lifelong warfarin is a handicap in terms of safety and convenience. Currently, the use of direct oral anticoagulants (DOACs) in CTEPH has increased with the advent of four DOACs. The safety of DOACs is superior to warfarin, with less intracranial bleeding in patients with non-valvular atrial fibrillation and venous thromboembolism. Edoxaban, the latest DOAC, also has proven efficacy and safety for those diseases in two large clinical trials; the ENGAGE-AF trial and HOKUSAI-VTE trial. The present trial seeks to evaluate whether edoxaban is non-inferior to warfarin in preventing worsening of CTEPH.

Methods and analysis

The KABUKI trial (is an investigator-initiated, multicentre, phase 3, randomised, single-blind, parallel-group, warfarin-controlled, non-inferiority trial to evaluate the efficacy and safety of edoxaban versus warfarin (vitamin K Antagonist) in subjects with chronic thromBoembolic pUlmonary hypertension taking warfarin (vitamin K antagonIst) at baseline) is designed to prove the non-inferiority of edoxaban to warfarin in terms of efficacy and safety in patients with CTEPH.

Ethics and dissemination

This study is approved by the Institutional Review Board of each participating institution. The findings will be published in a peer-reviewed journal, including positive, negative and inconclusive results.

Trial registration number

NCT04730037.

Protocol version

This paper was written per the study protocol V.4.0, dated 29 January 2021.