Balloon pulmonary angioplasty vs riociguat in patients with inoperable chronic thromboembolic pulmonary hypertension: A systematic review and meta-analysis

Clinical usefulness of endothelial progenitor cells in predicting the efficacy of riociguat in chronic thromboembolic pulmonary hypertension

Endothelial dysfunction is important in the pathology of pulmonary hypertension, and circulating endothelial progenitor cells (EPCs) have been studied to evaluate endothelial dysfunction. In patients with chronic thromboembolic pulmonary hypertension (CTEPH), riociguat reportedly increases the number of circulating EPCs. However, the relationship between EPC numbers at baseline and changes in clinical parameters after riociguat administration has not been fully elucidated. Here, we evaluated 27 treatment-naïve patients with CTEPH and analyzed the relationships between EPC number at diagnosis and clinical variables (age, hemodynamics, atrial blood gas parameters, brain natriuretic peptide, and exercise tolerance) before and after riociguat initiation. EPCs were defined as CD45dim CD34+ CD133+ cells and measured by flow cytometry. A low number of circulating EPCs at diagnosis was significantly correlated with increased reductions in mean pulmonary arterial pressure (mPAP) (correlation coefficient = 0.535, P = 0.004) and right atrial pressure (correlation coefficient = 0.618, P = 0.001) upon riociguat treatment. We then divided the study population into two groups according to the mPAP change: a weak-response group (a decrease in mPAP of 4 mmHg or less) and a strong-response group (a decrease in mPAP of more than 4 mmHg). The number of EPCs at diagnosis was significantly lower in the strong-response group than in the weak-response group (P = 0.022), but there were no significant differences in other clinical variables or in medication profiles. In conclusion, circulating EPC numbers could be a potential predictor of the therapeutic effect of riociguat in CTEPH patients.

Insufficiency of quality of life as the treatment endpoint for balloon pulmonary angioplasty in inoperable chronic thromboembolic pulmonary hypertension

Background and Objectives

The ability of a quality of life (QoL) to guide balloon pulmonary angioplasty (BPA) among patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) has not been fully investigated. This study explored the relationship between QoL scores and hemodynamics in CTEPH patients after BPA and examined whether QoL could be applied as a treatment endpoint.

Materials and Methods

This cohort study included patients with inoperable CTEPH who had undergone at least four sessions of BPA. The patients' demographic and clinical data as well as hemodynamic parameters and scores from the RAND 36-item short-form QoL questionnaire were recorded and compared before and after BPA.

Results

After BPA treatments, clinical characteristics, hemodynamic parameters, as well as QoL score improved significantly. A physical component summary (PCS) score of 35 or 46 can be used as the cutoff value for predicting better World Health Organization functional classification (WHO FC). Patients who had a higher PCS would have longer 6-min walk distance (6MWD), lower pulmonary vascular resistance (PVR), and better cardiac output (CO) both before and after BPA. However, 19 patients (55.9%) with a higher PCS score after BPA did not achieve the goal of mean pulmonary arterial pressure (mPAP) ≤30 mmHg. During the follow-up period, a significant reduction of PVR was observed, but the PCS score improved a little.

Conclusions

QoL is a useful tool for assessing the exercise endurance of patients with inoperable CTEPH treated with BPA, but is insufficient to serve as a treatment endpoint for BPA.

Emerging Role of Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Disease-Insights from the 2022 ESC Guidelines

In this article, we discuss the topic of chronic thromboembolic pulmonary disease (CTEPD) and the growing role of balloon pulmonary angioplasty (BPA) in its treatment. We present the pathophysiology of CTEPD which arises from an incomplete resolution of thrombi in the pulmonary arteries and leads to stenosis and occlusion of the vessels. The article focuses mainly on the chronic thromboembolic pulmonary hypertension (CTEPH) subpopulation for which prognosis is very poor when left untreated. We describe a multimodal approach to treating CTEPH, including pulmonary endarterectomy (PEA), BPA, and pharmacological therapies. Additionally, the benefits of pharmacological pre-treatment before BPA and the technical aspects of the procedure itself are outlined. It is emphasized that BPA does not replace PEA but serves as a complementary treatment option for eligible patients. We summarized efficacy and treatment goals including an improvement in functional and biochemical parameters before and after BPA. Patients who received pre-treatment with riociguat prior to BPA exhibited a notable reduction in the occurrence of less severe complications. However, elderly patients are still perceived as an especially vulnerable group. It is shown that the prognosis of patients undergoing BPA is similar to PEA in the first years after the procedure but the long-term prognosis of BPA still remains unclear. The 2022 ESC/ERS guidelines highlight the significant role of BPA in the multimodal treatment of CTEPH, emphasizing its effectiveness and recommending its consideration as a therapeutic option for patients with CTEPD, both with and without pulmonary hypertension. This review summarizes the available evidence for BPA, patient selection, procedural details, and prognosis and discusses the potential future role of BPA in the management of CTEPH.

Refined Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension: Initial Results of U.S. Regional Program

Objectives

We sought to evaluate the efficacy and safety of refined balloon pulmonary angioplasty (BPA) in the treatment of patients with chronic thromboembolic pulmonary hypertension (CTEPH).

Background

BPA is rapidly evolving therapeutic option for patients with nonsurgical CTEPH. There are few US studies that have reported on the outcomes of this novel therapeutic option.

Methods

This is a retrospective study of CTEPH patients that underwent BPA at Temple University Hospital. The primary efficacy endpoint was the change in pulmonary vascular resistance (PVR) after BPA as compared to baseline and the primary safety endpoint was the rate of hemoptysis within 24 hours. Secondary endpoints included death, WHO functional class, and 6-minute walk distance (6MWD). We used logistic regression to evaluate factors associated with a hemodynamic and functional response.

Results

A total of 211 BPA sessions were performed on 77 patients (average 2.7 ± 1.7 sessions/patient). After BPA the mean PVR improved by 26% (P<0.001) while the mean 6MWD improved by 71.7 meters (P <0.001) and WHO functional class improved by one functional class (P <0.001). Ten sessions (4.7%) were complicated by hemoptysis. The independent factors associated with a improved functional and hemodynamic response included the pre-procedural use of riociguat, reduce baseline PA compliance and > 3 BPA sessions per patient.

Conclusion

This single center study from the US showed that BPA with refined techniques in patients with CTEPH was safe and was associated with significant improvements in pulmonary hemodynamics and functional capacity.

New progress in diagnosis and treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease. Although great progress has been made in its diagnosis and treatment in recent years, its mortality rate is still very significant. The pathophysiology and pathogenesis of PAH are complex and involve endothelial dysfunction, chronic inflammation, smooth muscle cell proliferation, pulmonary arteriole occlusion, antiapoptosis and pulmonary vascular remodeling. These factors will accelerate the progression of the disease, leading to poor prognosis. Therefore, accurate etiological diagnosis, treatment and prognosis judgment are particularly important. Here, we systematically review the pathophysiology, diagnosis, genetics, prognosis and treatment of PAH.

Change in pulmonary arterial compliance and pulmonary pulsatile stress after balloon pulmonary angioplasty

OBJECTIVE

Although the underlying pathology of chronic thromboembolic pulmonary hypertension (CTEPH) is mechanical obliteration of the major pulmonary vessels, high pulsatile stress penetrating into the normal distal pulmonary microvasculature resulting from reduced pulmonary arterial compliance (CPA) may cause progressive deterioration in pulmonary hemodynamics. Hypothetically, balloon pulmonary angioplasty (BPA) may be beneficial in reducing CPA and pulsatile stress in patients with CTEPH.

METHODS

In total, 26 patients with available pre- and post-BPA right heart catheterization results were included in the study. BPA was performed in a series of staged procedures by 2 experienced interventional cardiologists.

RESULTS

The median CPA showed a 59.2% increase (1.03 to 1.64 mL/mm Hg, p=0.005). The median pre-BPA pulsatile stress product decreased by 20.7% (4,266 to 3,380 mm Hg/min, p=0.003). A linear regression model established that the percent change in CPA after BPA accounted for 21.8% of the explained variability in the change in 6-minute walk test (p=0.009).

CONCLUSION

Our results indicate that BPA decreases CPA and pulmonary pulsatile stress. These changes may be partly responsible for the improvement in functional capacity after BPA.

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.

Pulmonary endarterectomy

Chronic thromboembolic pulmonary hypertension is an underdiagnosed condition. Patients typically present with the symptoms of right heart failure. Diagnosis is usually done by radionuclide ventilation/perfusion (VQ) scan, high-quality multidetector computed tomography (CT) or pulmonary angiography at expert centers. Pulmonary endarterectomy remains the corner stone in management of chronic thromboembolic pulmonary hypertension. Deep hypothermic circulatory arrest is commonly used for the operation at most centers. In-hospital mortality ranges from 1.7 to 14.2%. Pulmonary hemorrhage, reperfusion lung injury, and right ventricular failure remain major early post-operative concerns. Five-year survival is reported to be 76 to 89%. Long-term outcome depends on residual pulmonary hypertension. Balloon pulmonary angioplasty and medical management play an adjunctive role. Here, we provide a comprehensive review on surgical management of chronic thromboembolic pulmonary hypertension.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension (PH) caused by thromboembolic disease with the secondary remodeling of the pulmonary vessels. The primary treatment of CTEPH is pulmonary thromboendarterectomy (PTE). However, some patients are not candidates for PTE because of surgically inaccessible thrombi or high operative risk and can be candidates for balloon pulmonary angioplasty (BPA), an emerging, lower risk treatment. This review discusses the patient selection, the technique, and comprehensive review of reported outcomes following BPA. BPA techniques have improved over the years, and so has its safety profile. Recent data show that after several sessions of BPA, patients who were not eligible for PTE had improvement in their hemodynamic profile, functional capacity, and 6-minute walk distance. Studies have shown that compared to riociguat, BPA has shown significant improvement in the functional capacity and hemodynamic measurements. Reperfusion pulmonary edema is a common complication after PTE and BPA, which may be due to vessel injury rather than pulmonary extravasation. Rates of complications have decreased especially after the use of optical coherence tomography, which helps in proper sizing of the balloons. Patients with CTEPH who are ineligible for PTE should be evaluated for BPA. In addition to medical therapy, BPA has shown promising clinical and hemodynamic outcomes in patients with CTEPH.

Balloon Pulmonary Angioplasty: State of the Art

Balloon pulmonary angioplasty (BPA) is a novel technique for the treatment of chronic thromboembolic pulmonary hypertension. While cardiologists need no introduction to the concept of balloon angioplasty, BPA has its own particular challenges. This article aims to provide the reader with an overview of BPA, starting with an introduction to chronic thromboembolic disease (CTED), the standard management of chronic thromboembolic pulmonary hypertension (CTEPH), technical challenges faced when performing BPA and the evidence base supporting its use. The second part of the article will focus on the future of BPA, in particular the areas where research is required to establish an evidence base to justify the role of BPA in CTEPH and CTED treatment.

Balloon pulmonary angioplasty vs. pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

Although balloon pulmonary angioplasty (BPA) and pulmonary endarterectomy (PEA) are effective in chronic thromboembolic pulmonary hypertension (CTEPH), the comparison of their efficacy and safety is still unclear. We identified studies through a systematic review of PubMed, Cochrane Library, and Embase and used a random effects meta-analysis model to synthesize estimates of weighted mean differences or combined effect size. In total, 54 studies were included in this meta-analysis. The survival rates at perioperative/in-hospital period, 2 years, and 3 years were 100%, 99%, and 97%, respectively, in BPA group and 93%, 90%, and 88%, respectively, in PEA group. The variation of 6-min walk distance was 141.80 m in BPA and 100.73 m in PEA when the follow-up was 1-6 months. At < 1-month, 1-6-month, and > 12-month follow-up, the changed results of mean pulmonary arterial pressure were - 18.31, - 17.00, and - 12.97 mmHg in BPA group and - 18.93, - 21.21, and - 21.35 mmHg in PEA group. At < 1-month and 1-6-month follow-up, the changed values of pulmonary vascular resistance were - 542.24 and - 599.77 dyne•s•cm^-5 in PEA group and - 443.49 and - 280.00 dyne•s•cm^-5 in BPA group. In addition, there was more wide variety of complications in PEA group than in BPA group. BPA might have higher survival rate (perioperative/in-hospital period, 2-year and 3-year follow-up) and fewer types of complications compared with PEA. The improvement in exercise capacity (1-6-month follow-up) in the BPA group might be more pronounced than in PEA group. Moreover, PEA might be superior in improvement of hemodynamic parameters (< 1-month, 1-6-month, and > 12-month follow-up).

Evolving spectrum of treatment for CTEPH

PURPOSE OF REVIEW

The present review provides an update on treatment of chronic thromboembolic pulmonary hypertension (CTEPH), a rare form of pulmonary hypertension characterized by precapillary pulmonary hemodynamic parameters with chronic thrombotic occlusion of the pulmonary vasculature.

RECENT FINDINGS

Pulmonary thromboendarectomy (PTE) remains the recommended treatment for patients with surgically accessible disease. Recent data suggest that patients preoperatively bridged with medical therapy may have improved outcomes but further research is needed. Riociguat improves hemodynamics, right ventricular function, quality of life, and functional capacity and is the drug of choice for patients with inoperable/persistent disease. Recently published data suggest that endothelin receptor blockers and treprostinil may also have a role in medical management of this patient population. A growing body of evidence indicates that in experienced centers balloon pulmonary angioplasty (BPA) may be a well tolerated and effective adjunct to pharmacological treatment for patients with inoperable disease affecting subsegmental vasculature.

SUMMARY

Untreated CTEPH carries significant morbidity and mortality. Recent publications provide a wealth of data on safety and efficacy of BPA for inoperable subsegmental disease, but its precise fit in the treatment algorithm, both pharmacological and procedural, requires further investigation. PTE remains the procedure of choice for surgically accessible disease.

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.

Treatment of pulmonary hypertension with riociguat: a review of current evidence and future perspectives

INTRODUCTION

Pulmonary arterial hypertension (PAH) is still a chronic disorder characterized by high morbidity and mortality. Chronic thromboembolic pulmonary hypertension (CTEPH) is another form of pulmonary hypertension (PH) for which pulmonary endarterectomy (PEA) is the treatment of choice. However, not all patients are operable, while PH is often recurrent or persistent. Thus, for both disorders novel treatment options are urgently needed.

AREAS COVERED

This review describes the mechanism of action of riociguat, a soluble guanylate cyclase (sGC) stimulator, with a dual mode of action. The most relevant publications are presented regarding the efficacy of riociguat in PAH and CTEPH, and also data regarding its potential effect on other forms of PH.

EXPERT OPINION

Riociguat is a first-in-class drug approved for the treatment of PAH as a monotherapy or added to endothelin-receptor antagonists as a sequential combination therapy, and for the treatment of inoperable CTEPH or persistent/recurrent PH after PEA. As it can stimulate sGC independently of NO, it could be beneficial in PAH patients with inadequate response to phosphodiesterase 5 inhibitors (PDE5i). Future studies are needed to evaluate whether drug switching is beneficial in PAH and which baseline markers could guide the optimal initial treatment selection.

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.

Balloon pulmonary angioplasty vs riociguat in patients with inoperable chronic thromboembolic pulmonary hypertension: A systematic review and meta-analysis

Backgrounds

No previous meta‐analyses have compared the efficacy and safety of BPA with riociguat therapy in inoperable CTEPH patients.

Methods

Relevant published studies were searched in the PubMed, Embase and ClinicalTrial.gov databases.

Results

Twenty‐three clinical trials including 1454 patients (631 underwent BPA; 823 underwent riociguat therapy) were analyzed. BPA was associated with a greater improvement in RAP (mean difference (MD) = −3.53 mmHg, 95% CI: [−4.85, −2.21] vs MD = −1.05 mmHg, 95% CI: [−1.82, −0.29]); mPAP (MD = −15.02 mmHg, 95% CI: [−17.32, −12.71] vs MD = −4.19 mmHg, 95% CI: [−5.58, −2.80]); PVR (standard MD = −1.32 woods, 95% CI: [−1.57, −1.08] vs standard MD = −0.65 woods, 95% CI: [−0.79, −0.50]); NYHA functional class (RR = 6.78, 95% CI: [3.14, 14.64] vs RR = 1.49, 95% CI: [1.07, 2.07]); and 6MWD (MD = 71.66 m, 95% CI: [58.34, 84.99] vs MD = 45.25 m, 95% CI: [36.51, 53.99]) than riociguat treatment. However, the increase in CO was greater with riociguat (MD = 0.78 L/min, 95% CI: [0.61, 0.96]) than with BPA (MD = 0.33 L/min, 95% CI: [0.06, 0.59]). No significant difference in cardiac index (CI) was found between BPA (MD = 0.40 L/min/m², 95% CI: [0.21, 0.58]) and riociguat (MD = 0.40 L/min/m², 95% CI: [0.26, 0.54]). The most common complications of BPA were pulmonary injury (0.3%‐5.6%) and pulmonary edema (0.8%‐28.6%). The most common adverse events of riociguat were headache, dizziness, hypotension and nasopharyngitis.

Conclusions

Our meta‐analysis indicates that BPA might be associated with greater improvements in exercise tolerance and pulmonary hemodynamics except for cardiac output and cardiac index than riociguat therapy. However, both of them were well tolerated.