Recent Advances in the Treatment of Pulmonary Arterial Hypertension

Continuous heart monitoring to evaluate treatment effects in pulmonary hypertension

BACKGROUND

The treatment of pulmonary hypertension (PH) has improved rapidly in recent decades. There is increasing evidence to support the role of early intervention and treatment in affecting clinical outcomes in PH.

OBJECTIVES

To assess treatment effects before and after the escalation of specific PH treatments using continuous heart monitoring with a Reveal LINQ loop recorder.

METHODS

Patients were compared before and after treatment escalation. Treatment escalation was defined as an additional pulmonary arterial hypertension (PAH) drug, pulmonary endarterectomy, percutaneous balloon angioplasty or bilateral lung transplantation. Specifically, changes in heart rate variability (HRV), heart rate (HR) and physical activity were assessed.

RESULTS

In this prospective study, 41 patients (27 with PAH and 14 with chronic thromboembolic pulmonary hypertension (CTEPH)) were enrolled. Among them, 15 (36.6%) patients underwent PH treatment escalation. Prior to escalation, patients were monitored for a median of 100 (range: 68-100) days and after therapy escalation for a median duration of 165 (range: 89-308) days. In the escalation group, there was a significant increase in HRV, physical activity indexed by daytime HR and a significant decrease in nighttime HR assessed at baseline and after treatment escalation in both the PAH and CTEPH groups. This was paralleled by significant improvements in WHO functional class, 6-min walking distance and N-terminal pro-b-type natriuretic peptide.

CONCLUSIONS

This is the first study to demonstrate an association between specific PH therapies and changes in HRV, HR nighttime and physical activity. This indicates the potential of continuous monitoring in the evaluation of treatment effects in PH.

The Xanthine Derivative KMUP-1 Inhibits Hypoxia-Induced TRPC1 Expression and Store-Operated Ca2+ Entry in Pulmonary Arterial Smooth Muscle Cells

Exposure to hypoxia results in the development of pulmonary arterial hypertension (PAH). An increase in the intracellular Ca2+ concentration ([Ca2+]i) in pulmonary artery smooth muscle cells (PASMCs) is a major trigger for pulmonary vasoconstriction and proliferation. This study investigated the mechanism by which KMUP-1, a xanthine derivative with phosphodiesterase inhibitory activity, inhibits hypoxia-induced canonical transient receptor potential channel 1 (TRPC1) protein overexpression and regulates [Ca2+]i through store-operated calcium channels (SOCs). Ex vivo PASMCs were cultured from Sprague-Dawley rats in a modular incubator chamber under 1% O2/5% CO2 for 24 h to elucidate TRPC1 overexpression and observe the Ca2+ release and entry. KMUP-1 (1 μM) inhibited hypoxia-induced TRPC family protein encoded for SOC overexpression, particularly TRPC1. KMUP-1 inhibition of TRPC1 protein was restored by the protein kinase G (PKG) inhibitor KT5823 (1 μM) and the protein kinase A (PKA) inhibitor KT5720 (1 μM). KMUP-1 attenuated protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 1 μM)-upregulated TRPC1. We suggest that the effects of KMUP-1 on TRPC1 might involve activating the cyclic guanosine monophosphate (cGMP)/PKG and cyclic adenosine monophosphate (cAMP)/PKA pathways and inhibiting the PKC pathway. We also used Fura 2-acetoxymethyl ester (Fura 2-AM, 5 μM) to measure the stored calcium release from the sarcoplasmic reticulum (SR) and calcium entry through SOCs in hypoxic PASMCs under treatment with thapsigargin (1 μM) and nifedipine (5 μM). In hypoxic conditions, store-operated calcium entry (SOCE) activity was enhanced in PASMCs, and KMUP-1 diminished this activity. In conclusion, KMUP-1 inhibited the expression of TRPC1 protein and the activity of SOC-mediated Ca2+ entry upon SR Ca2+ depletion in hypoxic PASMCs.

Prescription patterns of ambrisentan in some cities of Colombia

INTRODUCTION

Ambrisentan is a selective type A endothelin receptor antagonist that has shown significant effectiveness and safety in the management of patients with pulmonary hypertension. Its use pattern with real-world evidence in Colombia is unknown.

OBJECTIVE

The objective of this study is to determine the prescription patterns of ambrisentan in some cities of Colombia.

METHODS

A longitudinal descriptive study on the prescription patterns of ambrisentan in patients with pulmonary hypertension (all the groups) was conducted between January 2021 and December 2022 based on a population database of members of the Colombian Health System. Adherence at 1 year was determined using the Medication Possession Ratio (days the drug was dispensed/days from first dispensing to the end of the follow-up period × 100). Descriptive analysis was carried out.

RESULTS

Sixty-seven patients taking ambrisentan were identified in 10 cities of the country. The individuals had a median age of 51.5 years (interquartile range-IQR: 39.8-64.0 years), and 82.1% were women. The drug possession rate was 82.2% (IQR: 65.0-96.8%), and persistence at 1 year was present in 49.3% (n = 33) of the cases. The average dose was 8.8 ± 5.0 mg/day, and 76.1% (n = 51) received it in combination therapy, mainly with phosphodiesterase type 5 inhibitors (61.2%, n = 41).

CONCLUSIONS

Adherence to ambrisentan was good, but its persistence at 1 year was low. The dosages of the drug used were in accordance with the recommendations of the clinical practice guidelines, and it was used in combination therapy, especially with phosphodiesterase 5 inhibitors.

Recent Advances in the Treatment of Pulmonary Arterial Hypertension Associated with Connective Tissue Diseases

Pulmonary hypertension (PH) is a severe vascular complication of connective tissue diseases (CTD). Patients with CTD may develop PH belonging to diverse groups: (1) pulmonary arterial hypertension (PAH), (2) PH due to left heart disease, (3) secondary PH due to lung disease and/or hypoxia and (4) chronic thromboembolic pulmonary hypertension (CTEPH). PAH most often develops in systemic scleroderma (SSc), mostly in its limited variant. PAH-CTD is a progressive disease characterized by poor prognosis. Therefore, early diagnosis should be established. A specific treatment for PAH-CTD is currently available and recommended: prostacyclin derivative (treprostinil, epoprostenol, iloprost, selexipag), nitric oxide and natriuretic pathway: stimulators of soluble guanylate cyclase (sGC: riociguat) and phosphodiesterase-five inhibitors (PDE5i: sildenafil, tadalafil), endothelin receptor antagonists (ERA: bosentan, macitentan, ambrisentan). Moreover, novel drugs, e.g., sotatercept, have been intensively investigated in clinical trials. We aim to review the literature on recent advances in the treatment strategy and prognosis of patients with PAH-CTD. In this manuscript, we discuss the mechanism of action of PAH-specific drugs and new agents and the latest research conducted on PAH-CTD patients.

Design, Development, and Evaluation of Treprostinil Embedded Adhesive Transdermal Patch

Clinical application of treprostinil in pulmonary arterial hypertension is hampered by adverse effects caused by its high dosing frequency. The objective of this investigation was to Formulate an adhesive-type transdermal patch of treprostinil and evaluate it both in vitro and in vivo. A 3²-factorial design was utilized to optimize the selected independent variables (X₁: drug amount, X₂: enhancer concentration) on the response variables (Y₁: drug release, Y₂: transdermal flux). The optimized patch was evaluated for various pharmaceutical properties, skin irritation, and pharmacokinetics in rats. Optimization results signify considerable influence (p < 0.0001) of X₁ on both Y₁ and Y₂, as compared to X₂. The optimized patch possesses higher drug content (>95%), suitable surface morphology, and an absence of drug crystallization. FTIR analysis revealed compatibility of the drug with excipients, whereas DSC thermograms indicate that the drug exists as amorphous in the patch. The adhesive properties of the prepared patch confirm adequate adhesion and painless removal, while the skin irritation study confirms its safety. A steady drug release via Fickian diffusion and greater transdermal delivery (~23.26 µg/cm²/h) substantiate the potential of the optimized patch. Transdermal therapy resulted in higher treprostinil absorption (p < 0.0001) and relative bioavailability (237%) when compared to oral administration. Overall, the results indicate that the developed drug in the adhesive patch can effectively deliver treprostinil through the skin and could be a promising treatment option for pulmonary arterial hypertension.

New Drugs and Therapies in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension is a chronic, progressive disorder of the pulmonary vasculature with associated pulmonary and cardiac remodeling. PAH was a uniformly fatal disease until the late 1970s, but with the advent of targeted therapies, the life expectancy of patients with PAH has now considerably improved. Despite these advances, PAH inevitably remains a progressive disease with significant morbidity and mortality. Thus, there is still an unmet need for the development of new drugs and other interventional therapies for the treatment of PAH. One shortcoming of currently approved vasodilator therapies is that they do not target or reverse the underlying pathogenesis of the disease process itself. A large body of evidence has evolved in the past two decades clarifying the role of genetics, dysregulation of growth factors, inflammatory pathways, mitochondrial dysfunction, DNA damage, sex hormones, neurohormonal pathways, and iron deficiency in the pathogenesis of PAH. This review focuses on newer targets and drugs that modify these pathways as well as novel interventional therapies in PAH.

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.