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

Pulmonary Vasodilator Therapy in Pediatric Patients on Ventricular Assist Device Support: A Single-Center Experience and Proposal for Use

Pediatric precapillary pulmonary hypertension can develop in response to systemic atrial hypertension. Systemic atrial decompression following ventricular assist device (VAD) implantation may not sufficiently lower pulmonary vascular resistance (PVR) to consider heart transplant candidacy. Prostacyclins have been used in adult VAD patients with success, but pediatric data on safety and efficacy in this population are limited. We sought to describe our center's experience to show its safety and to present our current protocol for perioperative use. We reviewed our use of prostacyclin therapy in pediatric patients on VAD support with high PVR from 2016 to 2021. Of the 17 patients who met inclusion, 12 survived to transplant and 1 is alive with VAD in situ . All patients survived posttransplant. With continuous intravenous (IV) epoprostenol or treprostinil therapy, there were no bleeding complications or worsening of end-organ function. A significant reduction was observed in vasoactive inotropic scores by 49% in the first 24 hours post-prostacyclin initiation. The proportion of patients surviving to transplant in this high-risk cohort is favorable. In conclusion, prostacyclins may be safe to use in patients with elevated PVR as part of their VAD and transplant course and may provide a transplant option in those otherwise not candidates.

Treprostinil in Neonates with Congenital Diaphragmatic Hernia-Related Pulmonary Hypertension

OBJECTIVE

To describe our experience with treprostinil, evaluate correlations with cardiac function, and assess for adverse effects in neonates with congenital diaphragmatic hernia-related pulmonary hypertension (CDH-PH).

STUDY DESIGN

A retrospective review of a single-center prospective registry at a quaternary care children's hospital. Patients included in the study had CDH-PH treated with treprostinil between April 2013 and September 2021. Assessed outcomes were brain-type natriuretic peptide levels and quantitative echocardiographic parameters collected at baseline, 1 week, 2 weeks, and 1 month after treprostinil initiation. Right ventricular (RV) function was assessed by tricuspid annular plane systolic excursion Z-score and speckle tracking echocardiography (global longitudinal and free wall strain). Septal position and left ventricular (LV) compression were assessed by eccentricity index and M-mode Z-scores.

RESULTS

Fifty-one patients were included, with an average expected/observed lung-to-head ratio of 28.4 ± 9.0%. Most patients required extra-corporeal membrane oxygenation (n = 45, 88%). Survival to hospital discharge was 31/49 (63%). Treprostinil was initiated at a median age of 19 days with a median effective dose of 34 ng/kg/minute. Median baseline brain-type natriuretic peptide level decreased from 416.9 pg/mL to 120.5 pg/mL after 1 month. Treprostinil was associated with improved tricuspid annular plane systolic excursion Z-score, RV global longitudinal strain, RV free wall strain, LV eccentricity index, and LV diastolic and systolic dimensions, reflecting less compression by the RV, regardless of ultimate patient survival. No serious adverse effects were recorded.

CONCLUSIONS

In neonates with CDH-PH, treprostinil administration is well tolerated and is associated with improved RV size and function.

International practice heterogeneity in pre-transplant management of pulmonary hypertension related to pediatric left heart disease

BACKGROUND

Elevated pulmonary vascular resistance (PVR) in the setting of left heart failure may contribute to poor outcomes after pediatric heart transplant (HTx), but peri-transplant management is variable.

METHODS

We sought to characterize international practice by surveying physicians at pediatric HTx centers.

RESULTS

We received 49 complete responses from 39 centers in 16 countries. Most respondents are pediatric cardiologists (90%), practice at centers offering heart (86%) and lung (55%) transplant, and perform pre-HTx acute vasoreactivity testing (AVT, 88%) in patients with elevated PVR. Half (51%) reported defining a PVR cutoff for HTx eligibility as ≤6 WU m² (56%) post-AVT (84%). The highest post-AVT PVR ever accepted for HTx ranged from 3-14.4 (median 6) WU m² . To treat elevated pre-transplant PVR, phosphodiesterase type 5 inhibitors are most common (65%) followed by oxygen (31%), nitric oxide (14%), endothelin receptor antagonists (11%), and prostacyclins (6%). Nearly a third (31%) do not routinely use pulmonary vasodilators without implantation of a left ventricular assist device (LVAD). Case scenarios highlight treatment variability: in a restrictive cardiomyopathy scenario, HTx listing with post-transplant vasodilator therapy was favored, whereas in a Shone's complex patient with fixed PVR, LVAD ± pulmonary vasodilators followed by repeat catheterization was most common. Management of dilated cardiomyopathy with reactive PVR was variable. Most continue vasodilator therapy until HTx (16%), PVR normalizes (16%) or ≤6 months.

CONCLUSIONS

Management of elevated PVR in children awaiting HTx is heterogenous. Evidence-based guidelines are needed to allow for longitudinal determination of optimal outcomes and standardized care.

Subcutaneous Treprostinil Improves Surgical Candidacy for Next Stage Palliation in Single Ventricle Patients With High-Risk Hemodynamics

Single ventricle (SV) patients with pulmonary vascular disease (SV-PVD) are considered poor surgical candidates for Glenn or Fontan palliation. Given limited options for Stage 1 (S1) and Stage 2 (S2) SV patients with SV-PVD, we report on the use of subcutaneous treprostinil (TRE) to treat SV-PVD in this population. This single-center, retrospective cohort study examined SV patients who were not candidates for subsequent surgical palliation due to SV-PVD and were treated with TRE. The primary outcome was ability to progress to the next surgical stage; secondary outcomes included changes in hemodynamics after TRE initiation. Between 3/2014 and 8/2021, 17 SV patients received TRE for SV-PVD: 11 after S1 and 6 after S2 (median PVR 4.1 [IQR 3.2-4.8] WU*m2 and 5.0 [IQR 1.5-6.1] WU*m2, respectively). Nine of 11 (82%) S1 progressed to S2, and 2 (18%) underwent heart transplant (HTx). Three of 6 (50%) S2 progressed to Fontan, 1 underwent HTx and 2 are awaiting Fontan on TRE. TRE significantly decreased PVR in S1 patients with median post-treatment PVR of 2.0 (IQR 1.5-2.6) WU*m2. TRE can allow for further surgical palliation in select pre-Fontan patients with SV-PVD, obviating the need for HTx. Improvement in PVR was significant in S1 patients and persisted beyond discontinuation of therapy for most patients.

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.