Use of subcutaneous treprostinil in pediatric pulmonary arterial hypertension-Bridge-to-transplant or long-term treatment?

The effects of standardized intravenous treprostinil in pulmonary arterial hypertension patients after total cavo-pulmonary connection procedure

OBJECTIVE

Total cavo-pulmonary connection (TCPC) is a palliative treatment for single ventricular malformations. For high-risk patients (preoperative mean pulmonary arterial pressure, mPAP > 15 mmHg), between the inhaled and oral targeted medications, the application of intravenous treprostinil as a bridge therapy to achieve "seamless" management is core postoperative treatment. This study intends to explore the effect of different administration regimens on early postoperative recovery.

METHODS

This was a retrospective cohort study. High-risk pediatric patients (age ≤ 14 years) who underwent TCPC procedure in Fu Wai Hospital from 2015 to 2022 were included. Since the regimen of treprostinil was standardized in our center in 2021, the patients in 2020 and before were included in group 1, patients in 2021 and 2022 were included in group 2. The hemodynamic parameters were compared before and after the maintenance dose of treprostinil. The differences of demographic characteristics, surgical data and postoperative recovery were compared between the two groups.

RESULTS

A total of 51 pediatric patients were included. Group 1 included 35 patients who received treprostinil at 1-3 postoperative days and an average dose of 12 ± 4 ng/(kg·min). Group 2 included 16 patients who received treprostinil within postoperative 1 day and an average dose of 22 ± 7 ng/(kg·min). There were no significant differences between the two groups in terms of age, weight, preoperative percutaneous oxygen saturation and mPAP,  heterotaxy syndrome, TCPC procedure type, other concurrent procedure, cardiopulmonary bypass time and aortic cross-clamp proportion (p > 0.05). After 24 h of treprostinil treatment, the mPAP in group 1 reduced from 17 ± 3 mmHg to 15 ± 2 mmHg (p < 0.001), and in group 2 from 17 ± 2 mmHg to 14 ± 2 mmHg (p < 0.001), with no difference between groups. In the postoperative recovery, patients in Group 2 exhibited a reduced duration of mechanical ventilation, 19 (11, 25) hours vs 69 (23, 189) hours, p = 0.001; a shorter stay in the ICU, 8 (6, 12) days vs 16 (9,26) days, p = 0.006; and a shorter postoperative length of stay, 27 (17,55) days vs 39 (29,58) days, p = 0.032. Patients in Group 2 also exhibited a lower incidence of thromboembolic events, 0 (0/26) vs 26% (9/35), p = 0.043; and the need for renal replacement therapy, 0 (0/26) vs 31% (11/35), p = 0.011.

CONCLUSION

Treprostinil reduces pulmonary artery pressure after TCPC procedure. The standardized application of treprostinil may improve the postoperative recovery which should be proven by randomized controlled trials or matched cohort studies in the future.

Advances in targeted therapy for pulmonary arterial hypertension in children

Pulmonary arterial hypertension (PAH) is a rare and devastating disease of the pulmonary vasculature with a high morbidity and mortality rate in infants and children. Currently, treatment approaches are mostly based on adult guidelines and pediatrician clinical experience, focusing on specific pulmonary antihypertensive therapy and conventional supportive care. The advent of targeted drugs has led to significant advances in the treatment of PAH in children, including endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and prostacyclins, which have been studied and proven to improve hemodynamics and functional class in children PAH. A new targeted drug, riociguat, is assessing its safety and efficacy in clinical trials. However, more randomized controlled studies are needed to evaluate the combination of drugs, treatment strategies, and clinical endpoints of targeted therapy in children PAH. In this review, we summarize the research advances of PAH-targeted therapy in children over the last decade in order to provide a theoretical basis for future studies.

CONCLUSION

Pulmonary arterial hypertension (PAH) is a rare and devastating pulmonary vascular disease that is associated with a variety of diseases of any age in childhood onset.

WHAT IS KNOWN

• Therapeutic strategies for targeted drugs for PAH in children are based almost exclusively on data from adult studies and clinical experience of pediatric specialists. • Due to the complex etiology of PAH in children and the relative lack of clinical trial data, the selection of appropriate targeted drug therapy remains difficult.

WHAT IS NEW

• We redefine the definition of pulmonary arterial hypertension in children and summarize the progress of targeted therapy of pulmonary arterial hypertension in children in the past ten years. • The dosage and adverse reactions were summarized, and the mechanism of action was drawn according to the available targeted drugs. It can provide theoretical support for the development of guidelines and treatment strategies for the diagnosis and treatment of pulmonary arterial hypertension in children.

Subcutaneous use of treprostinil in pediatric pulmonary hypertension patients: A report of three cases

Treprostinil was approved by the United States Food and Drug Administration for use in the treatment of pulmonary arterial hypertension in 2002. Intravenous or subcutaneous treprostinil is used in pulmonary arterial hypertension patients in the functional classes of II-IV to alleviate exercise-related symptoms, or in cases where epoprostenol treatment should be reduced due to side effects. In this article, we describe three pediatric cases of pulmonary arterial hypertension in whom subcutaneous treprostinil was used.

Pharmacokinetics of treprostinil in children with functional single-ventricle pulmonary arterial hypertension: a randomized controlled trial

Background

Application of Treprostinil (TRE) in the patients with single ventricle (SV) physiology is very limited, and the optimal dose for children has not been determined. In this study, we aimed to analyze plasma samples to assess the attainment of clinically therapeutic concentrations of TRE and its efficacy and safety in the treatment of pediatric functional SV pulmonary arterial hypertension (FSV-PAH)..

Methods

Pediatric patients with FSV-PAH were recruited in this study. IV TRE at an initial rate of 5 ng/kg/min was administered through the femoral vein with an increase in rate to 10 ng/kg/min every 30 minuntil the aiming dose of 80 ng/kg/min had been reached. The drug was gradually discontinued after 12 h of treatment at a stable dose. The mean postoperative pulmonary artery pressure (mPAP), pulmonary-to-systemic arterial pressure ratio (Pp/Ps), and the ratio between arterial oxygen partial pressure and inhaled oxygen concentration (PaO₂/FiO₂) were used to evaluate the efficacy of TRE treatment. A multiple linear regression model was used to explore the relevant factors associated with TRE blood concentration.

Results

A total of eight patients were enrolled in the investigation, with an age range of 2.5-9.9 years. The median stable dose of TRE was 70 ng/kg/min with a range of 55-75 ng/kg/min. The median subliminal dose was 55 ng/kg/min with a range of 25-75 ng/kg/min. A linear relationship was established between the TRE dose and the plasma concentration. TRE blood concentrations were associated with dose and patient height. After TRE treatment, mPAP, Pp/Ps, and PaO₂/FiO₂ were significantly improved (P<0.05).

Conclusions

A linear relationship was found between the blood concentration of TRE and its dose. IV TRE was an effective therapy without serious side effects in pediatric patients with FSV-PAH.

Trial Registration

ClinicalTrials.gov Identifier: NCT02865733.

Treprostinil improves hemodynamics and symptoms in children with mild pulmonary hypertension awaiting heart transplantation

BACKGROUND

Treprostinil, a prostacyclin analog, is a safe and effective therapy for children with PAH; however, the use of this agent in children with mild PVR elevations related to HF, including those with SV congenital heart disease awaiting HT, is understudied. We describe the hemodynamic and symptomatic changes in pediatric patients awaiting HT treated with treprostinil.

METHODS

Single-center retrospective review of all patients was listed for HT who received treprostinil during the listing period. Changes in hemodynamic and functional indices between the baseline catheterization (prior to drug initiation), and prior to HT, and patient outcomes were analyzed.

RESULTS

Among 16/17 (94%) who survived to HT, 8 (50%) were female, and 10 (63%) had SV physiology. The median age at drug initiation was 9 (IQR: 1, 14) years. The median duration of therapy prior to HT was 253 (IQR: 148, 504) days. Treprostinil significantly decreased PVR (3.8 vs 3.1 WU, P = .03), while mLA or mPCW pressure did not change (11 vs 13 mm Hg, P = .9). HF symptoms improved in 9/15 (60%) patients without VAD support prior to drug initiation, including 4/10 (40%) who did not receive a VAD any point while awaiting HT.

CONCLUSIONS

Treprostinil may be used safely in patients with mild PAH awaiting HT, including those with SV disease. PVR falls without substantial increases in mLA/mPCW pressure. HF symptoms improve in some patients.

Thrombocytopenia During Prostacyclin Analogue Therapies of Pulmonary Arterial Hypertension-Possible Pathomechanisms and Implications

Pulmonary arterial hypertension is a quite rare, but problematic disease in everyday cardiologists' practice. Prostanoids are the most important group of drugs used in this disease. One of the biggest problems encountered during treatment with analogs of prostacyclin is thrombocytopenia. Based on hematological guidelines we suggest common therapeutic schemes depending on the number of platelets or the severity of bleeding conducting the therapy.

Use of Treprostinil in Pediatric Pulmonary Hypertension: Case Reports and Review of the Literature

BACKGROUND

Add-on therapy with prostacyclin in pediatric refractory pulmonary hypertension (PH) poses a challenge, especially when considering continuous intravenous administration in younger children. A search for alternate routes of drug delivery has led to the clinical investigation of stable and long-acting prostacyclin analogues, such as subcutaneous treprostinil. We reported 2 pediatric cases of PH treated with subcutaneous treprostinil and reviewed the literature on treprostinil use in children.

METHOD

The literature review used 3 electronic databases and a combination of terms (treprostinil, pediatric, PH, prostanoid, etc). We also searched for pediatric clinical trials on treprostinil registered on international clinical trial registries.

RESULTS

The reported cases highlighted the multifactorial nature of PH in pediatrics: a female child with a giant omphalocele, and intracardiac and extracardiac shunts; and a male premature child with a congenital diaphragmatic hernia and long-term PH. The literature review identified 19 studies reporting treprostinil use in 421 children with various types of PH (groups 1 and 3). Subcutaneous treprostinil was the most administered formulation, at a mean dose of 40 ng/kg/min. Overall, 12 clinical trials on treprostinil for children with PH were registered on the clinical trial registries. Most authors concluded that subcutaneous treprostinil was effective, well tolerated, and represented an alternative to intravenous epoprostenol.

CONCLUSIONS

Subcutaneous treprostinil may be a useful adjunct in the therapeutic algorithm for children with severe PH, refractory to oral drugs, and after a complete check-up for all PH etiologies.

Management of Pulmonary Arterial Hypertension in the Pediatric Patient

PURPOSE OF REVIEW

Pediatric pulmonary arterial hypertension (PAH) is associated with significant morbidity and mortality. Herein we review the diagnosis and classification for pediatric PAH and detail the current therapeutic options available for use in the pediatric PAH population.

RECENT FINDINGS

Classification and treatment of pediatric PAH is guided by adult criteria and treatment algorithms, yet the distribution of factors contributing to PAH in children differs significantly from that seen in adults. It is necessary to understand these differences in order to appropriately tailor therapy to the needs of the child or adolescent. An expanding array of targeted PAH drugs are now approved for use in adults, and many of these drugs are used "off-label" to treat children and adolescents with PAH. Use of these novel therapies has coincided with marked improvement in outcomes, suggesting significant benefit. However, because most of these drugs have not been studied in rigorous randomized, controlled trials in children, it is critical that physicians understand their mechanisms of action, potential benefits, and safety profiles. Pediatric PAH outcomes have improved substantially in the modern era, coinciding with the "off-label" use of targeted PAH drugs in children and adolescents. Ideally, care should be provided at centers with specialized expertise in the diagnosis and treatment of pediatric PAH by providers who understand the appropriate diagnostic algorithms, classification schemes, and treatment approaches.