Mark-Jan Ploegstra

Identification of treatment goals in paediatric pulmonary arterial hypertension

To be able to design goal-oriented treatment strategies in paediatric pulmonary arterial hypertension (PAH), we aimed to identify treatment goals by investigating the prognostic value of treatment-induced changes in noninvasive predictors of transplant-free survival. 66 consecutive, treatment-naïve paediatric PAH patients in the Dutch National Network for Paediatric Pulmonary Hypertension who started taking PAH-targeted drugs between January 2000 and April 2013 underwent prospective, standardised follow-up. Clinical, biochemical and echocardiographic measures were longitudinally collected at treatment initiation and follow-up, and their respective predictive values for transplant-free survival were assessed. Furthermore, the predictive values of treatment-induced changes were assessed. From the identified set of baseline predictors, the variables World Health Organization functional class (WHO-FC), N-terminal pro-brain natriuretic peptide (NT-proBNP) and tricuspid annular plane systolic excursion (TAPSE) were identified as follow-up predictors in which treatment-induced changes were associated with survival. Patients in whom these variables improved after treatment showed better survival (p<0.002). Therefore, WHO-FC, NT-proBNP and TAPSE are not only predictors of transplant-free survival in paediatric PAH but can also be used as treatment goals, as treatment-induced improvements in these variables are associated with improved survival. The identification of these variables allows for the introduction of goal-oriented treatment strategies in paediatric PAH. Improving WHO-FC, NT-proBNP and TAPSE are valid treatment goals in paediatric pulmonary arterial hypertension http://ow.ly/y4GJn

Sildenafil add-on therapy in paediatric pulmonary arterial hypertension, experiences of a national referral centre

Objective In paediatric pulmonary arterial hypertension (PAH), the effectiveness of add-on combination PAH-therapy has not yet been systematically studied. The purpose of this study was to determine the effect of sildenafil add-on therapy in paediatric PAH patients treated with bosentan. Methods In this observational study within a national paediatric patient cohort, follow-up data of 24 consecutive paediatric PAH patients initially treated with bosentan monotherapy and prospectively followed at the Dutch national referral centre for paediatric PAH in 2007–2013, were reviewed. Patients received add-on sildenafil therapy in case of clinical worsening. Results Fifteen children received add-on sildenafil therapy; nine remained on bosentan monotherapy. Patient characteristics, 6-minute walk distance (6MWD), WHO functional class (WHO-FC), N-terminal pro-Brain Natriuretic Peptide (NT-proBNP), and haemodynamic measurements at bosentan start were similar in both patient groups. In children with clinical worsening, sildenafil add-on therapy improved 6MWD at 5, 10, 15 and 21 months of follow-up, improved WHO-FC at 10, 15 and 21 months and stabilised NT-proBNP. Patients who received add-on sildenafil therapy had more advanced disease progression during bosentan monotherapy. Despite that, they had better or, at least, no worse survival compared to patients who remained on bosentan monotherapy. Conclusions In children with PAH, sildenafil add-on therapy indicated by clinical deterioration on bosentan monotherapy, was associated with a significant improvement of WHO-functional class and 6MWD. Despite clinical deterioration on bosentan monotherapy, patients receiving sildenafil add-on therapy, had either better or, at least, no worse survival than patients remaining on bosentan monotherapy.

Prognostic factors in pediatric pulmonary arterial hypertension: A systematic review and meta-analysis

BACKGROUND Despite the introduction of targeted therapies in pediatric pulmonary arterial hypertension (PAH), prognosis remains poor. For the definition of treatment strategies and guidelines, there is a high need for an evidence-based recapitulation of prognostic factors. The aim of this study was to identify and evaluate prognostic factors in pediatric PAH by a systematic review of the literature and to summarize the prognostic value of currently reported prognostic factors using meta-analysis. METHODS AND RESULTS Medline, EMBASE and Cochrane Library were searched on April 1st 2014 to identify original studies that described predictors of mortality or lung-transplantation exclusively in children with PAH. 1053 citations were identified, of which 25 were included for further analysis. Hazard ratios (HR) and 95% confidence intervals were extracted from the papers. For variables studied in at least three non-overlapping cohorts, a combined HR was calculated using random-effects meta-analysis. WHO functional class (WHO-FC, HR 2.7), (N-terminal pro-) brain natriuretic peptide ([NT-pro]BNP, HR 3.2), mean right atrial pressure (mRAP, HR 1.1), cardiac index (HR 0.7), indexed pulmonary vascular resistance (PVRi, HR 1.3) and acute vasodilator response (HR 0.3) were identified as significant prognostic factors (p ≤ 0.001). CONCLUSIONS This systematic review combined with separate meta-analyses shows that WHO-FC, (NT-pro)BNP, mRAP, PVRi, cardiac index and acute vasodilator response are consistently reported prognostic factors for outcome in pediatric PAH. These variables are useful clinical tools to assess prognosis and should be incorporated in treatment strategies and guidelines for children with PAH.

Echocardiography in pediatric pulmonary arterial hypertension: early study on assessing disease severity and predicting outcome

Background—The value of echocardiography in assessing disease severity and predicting outcome in pediatric pulmonary arterial hypertension (PAH) is insufficiently defined. The aim of this study was to describe correlations between echocardiography and disease severity and outcome in pediatric PAH. Methods and Results—Forty-three consecutive children (median age, 8.0 years; range, 0.4–21.5) with idiopathic/hereditary PAH (n=25) or PAH associated with congenital heart disease (n=18) were enrolled in a prospective single-center observational study. Anatomic and right ventricular-functional variables were obtained by two-dimensional echocardiography and Doppler-echocardiography at presentation and at standardized follow-up and were correlated with measures of disease severity (World Health Organization functional class [WHO-FC], N-terminal-pro-B-type natriuretic peptide, hemodynamics) and lung-transplantation–free survival. Right atrial and right ventricular dimensions correlated with WHO-FC and hemodynamics (P<0.05), whereas left ventricular dimensions correlated with hemodynamics and survival (P<0.05). Right-to-left ventricular dimension ratiocorrelated with WHO-FC, hemodynamics and survival (P<0.05). Right ventricular ejection time correlated with hemodynamics and survival (P<0.05) and tended to correlate with WHO-FC (P=0.071). Tricuspid annular plane systolic excursion correlated with WHO-FC, mean right atrial pressure and survival (P<0.05). Conclusions—This early descriptive study shows that echocardiographic chararacteristics of both the right and the left heart correlate with disease severity and outcome in pediatric PAH, both at presentation and during the course of the disease. The preliminary data from this study support the potential value of echocardiography as a tool in guiding management in children with PAH.Background— The value of echocardiography in assessing disease severity and predicting outcome in pediatric pulmonary arterial hypertension (PAH) is insufficiently defined. The aim of this study was to describe correlations between echocardiography and disease severity and outcome in pediatric PAH. Methods and Results— Forty-three consecutive children (median age, 8.0 years; range, 0.4–21.5) with idiopathic/hereditary PAH (n=25) or PAH associated with congenital heart disease (n=18) were enrolled in a prospective single-center observational study. Anatomic and right ventricular-functional variables were obtained by two-dimensional echocardiography and Doppler-echocardiography at presentation and at standardized follow-up and were correlated with measures of disease severity (World Health Organization functional class [WHO-FC], N-terminal-pro-B-type natriuretic peptide, hemodynamics) and lung-transplantation–free survival. Right atrial and right ventricular dimensions correlated with WHO-FC and hemodynamics ( P <0.05), whereas left ventricular dimensions correlated with hemodynamics and survival ( P <0.05). Right-to-left ventricular dimension ratiocorrelated with WHO-FC, hemodynamics and survival ( P <0.05). Right ventricular ejection time correlated with hemodynamics and survival ( P <0.05) and tended to correlate with WHO-FC ( P =0.071). Tricuspid annular plane systolic excursion correlated with WHO-FC, mean right atrial pressure and survival ( P <0.05). Conclusions— This early descriptive study shows that echocardiographic chararacteristics of both the right and the left heart correlate with disease severity and outcome in pediatric PAH, both at presentation and during the course of the disease. The preliminary data from this study support the potential value of echocardiography as a tool in guiding management in children with PAH.

Clinical Worsening as Composite Study End Point in Pediatric Pulmonary Arterial Hypertension

BACKGROUND Clinical worsening (CW), an increasingly used composite end point in adult pulmonary arterial hypertension (PAH), has not yet been evaluated in pediatric PAH. This study aims to evaluate the usefulness of CW in pediatric PAH by assessing the event incidence and prognostic value of each separate component of CW and of the composite CW end point. METHODS Seventy pediatric patients with PAH from the Dutch National Network for Pediatric Pulmonary Hypertension, who started PAH-targeted therapy between January 2000 and January 2014, were included in the study and underwent standardized follow-up. The following CW components were prospectively registered: death, lung transplantation (LTx), PAH-related hospitalizations, initiation of IV prostanoids, and functional deterioration (World Health Organization functional-class deterioration, ≥ 15% decrease in 6-min walk distance, or both). The longitudinal event incidence and prognostic value were assessed for each separate component and their combination. RESULTS The end-point components of death, LTx, hospitalizations, initiation of IV prostanoids, and functional deterioration occurred with a longitudinal event rate of 10.1, 2.5, 21.4, 9.4 and 48.1 events per 100 person-years, respectively. The composite CW end point occurred 91.5 times per 100 person-years. The occurrences of either hospitalization, initiation of IV prostanoids, or functional deterioration were predictive of death or LTx (P < .001 for each component). In this cohort, 1-, 3-, and 5-year transplant-free survival was 76%, 64%, and 56%, respectively. Freedom from CW at 1, 3, and 5 years was 43%, 22%, and 17%, respectively. CONCLUSIONS CW occurred with a high event incidence and each of the soft end-point components was predictive of death or LTx. This supports the usefulness of CW as a study end point in clinical trials in pediatric PAH.

Physical Activity in Pediatric Pulmonary Arterial Hypertension Measured by Accelerometry. A Candidate Clinical Endpoint

&NA; Rationale: The development of evidence‐based treatment guidelines for pediatric pulmonary arterial hypertension (PAH) is hampered by lack of pediatric clinical trials. Trial design is hampered by lack of a feasible clinical endpoint in this population. Objectives: To evaluate the use of accelerometry for measuring physical activity (PA) in pediatric PAH and to investigate its correlation with clinical disease severity markers. Methods: We included children from the Dutch National Network for Pediatric Pulmonary Hypertension. Control patients were recruited from the outpatient cardiology clinic of the Beatrix Childrens Hospital. Children were asked to wear the accelerometer for 7 days. Vector magnitude counts per minute (VM CPM) and time per day spent in different PA intensity levels were defined as accelerometer outcomes. Measurements and Main Results: VM CPM was lower in children with PAH (n = 29) than in controls (n = 60; 647 vs. 921; P < 0.001). Children with PAH spent less time in moderate and vigorous PA (13 vs. 29 min/d and 2 vs. 13 min/d, respectively; P < 0.001). Time spent in moderate and vigorous PA correlated inversely with World Health Organization functional class. Time spent in moderate PA correlated positively with 6‐minute‐walk distance. In post hoc analyses, VM CPM and time spent in moderate/vigorous combined and vigorous PA were associated with outcome (P ≤ 0.044). Conclusions: PA is markedly decreased in children with PAH. Accelerometer output correlated with clinical disease severity markers and may predict outcome. We showed an exciting potential of PA as a meaningful endpoint for clinical trials in pediatric PAH, although its clinical utility and prognostic value need to be further validated.

Clinical classification in pediatric pulmonary arterial hypertension associated with congenital heart disease

Congenital heart disease (CHD) is a frequent cause of pediatric pulmonary arterial hypertension (PAH), with diverse etiology and outcome. We aimed to describe phenotypic heterogeneity in pediatric PAH associated with CHD (PAH-CHD), assess the applicability of the Nice CHD classification, and explore whether this classification accurately reflects patient/disease characteristics and survival. All children with CHD from a contemporary cohort of consecutive pediatric PAH patients followed in three major referral centers (Denver, New York, the Netherlands) were characterized and classified on the basis of the latest proposed clinical classification for PAH-CHD (World Symposium on Pulmonary Hypertension, Nice, 2013). According to this classification, 24% of 134 children were classified into group 1, 14% into group 2, 19% into group 3, and 30% into group 4; 11% could not be classified. Types of CHD and hemodynamic profile differed between groups, with the highest right atrial pressure in group 4 (P < 0.040). Group 3 children had Down syndrome less frequently (P = 0.011) but other (un)defined syndromes most frequently (P = 0.063) and received most intense PAH-targeted therapy (P = 0.003). With 15 deaths and one lung transplant (12%; median follow-up: 4.3 years), survival differences could not be demonstrated between the groups in the Nice CHD classification. Pediatric PAH-CHD is a heterogeneous condition frequently associated with extracardiac, developmental factors that are believed to affect disease development. The Nice CHD classification identifies groups with specific patient/disease characteristics. However, a substantial proportion of children could not be classified. Group 3 forms a distinct disease entity. Its prognostic value could not be determined because of the low number of events. The Nice CHD classification supports clinical characterization of PAH-CHD; however, further refinement is needed to classify all children with PAH-CHD.

Pulmonary arterial stiffness indices assessed by intravascular ultrasound in children with early pulmonary vascular disease : Prediction of advanced disease and mortality during 20-year follow-up

Aims Prognosis in children with pulmonary vascular disease (PVD) is closely linked to right ventricular (RV) failure due to increased RV-afterload. Pulmonary arterial (PA) stiffening is known to occur early in the course of PVD and constitutes a main component of RV-afterload. This study aimed to evaluate the clinical value of PA-stiffness in children with PVD by determining its association with advanced pulmonary arterial hypertension (PAH) and mortality at long-term follow-up. Methods and results Forty-one children with various stages of arterial PVD, defined as mean PA-pressure  ≥20 mmHg and/or pulmonary-to-systemic flow-ratio  ≥1.2, and mean pulmonary capillary wedge pressure  <15 mmHg, underwent cardiac catheterization with intravascular ultrasound (IVUS) imaging between 1994 and 1997 with follow-up until 2015. PA-stiffness indices evaluated were PA-area-compliance (PA-compliance) and PA-area-distensibility (PA-distensibility). During follow-up, advanced PAH was determined by echocardiography and cardiac catheterization. During a median follow-up of 19 years, in 31 (76%) patients PVD had reversed and 10 (24%) had advanced PAH. Six (15%) died due to PVD. In addition to conventional haemodynamics, PA-compliance and PA-distensibility were associated with advanced PAH at long-term follow-up (adjusted OR [95% CI] 0.56 [0.37-0.85] and 0.52 [0.31-0.86]), and mortality (adjusted HR [95% CI] 0.60 [0.41-0.87] and 0.67 [0.49-0.90]). Also in a subgroup of patients with favourable haemodynamics, baseline PA-compliance and PA-distensibility were lower in patients with advanced PAH at follow-up (P  =  0.002 /P  =  0.030). Conclusion In children with PVD, PA-stiffness indices assessed by IVUS predict advanced PAH and mortality at long term follow-up. Especially in patients with favourable haemodynamics, assessment of intrinsic PA-stiffness may enhance the prognostication of disease progression and survival.

Identification of gaps in the current knowledge on pulmonary hypertension in extremely preterm infants: A systematic review and meta-analysis

BACKGROUND Pulmonary hypertension complicates the clinical course of extremely preterm infants and is associated with bronchopulmonary dysplasia (BPD). However, prevalence, risk factors, and outcome of pulmonary hypertension in these infants are insufficiently known. This systematic review and meta-analysis aims to provide an up-to-date overview of available data on prevalence, risk factors, and outcome of pulmonary hypertension and to identify current knowledge gaps. METHODS Medline, EMBASE, and the Cochrane Library databases were searched in July 2017. Two authors reviewed titles/abstracts and full-texts. Eligible studies reported prevalence, patient characteristics or mortality of infants with/without pulmonary hypertension. Studies were excluded if they did not include extremely preterm infants. Only similar study samples (selected infants with BPD or infants both with/without BPD) were compared in the meta-analyses. RESULTS Of 1829 unique articles identified, 25 were eligible for inclusion. Pulmonary hypertension was observed in infants with BPD (20%, 95% confidence interval [CI] 14, 25), but also in those without BPD (2%, 95% CI 0, 8). Infants with severe BPD were most at risk of pulmonary hypertension (risk ratio [RR] 2.7, 95% CI 1.7, 4.2). Infants with pulmonary hypertension were more at risk of mortality (RR 4.7, 95% CI 2.7, 8.3). CONCLUSIONS Pulmonary hypertension occurs in particularly in infants with severe BPD, and increases risk of mortality. Due to selected study populations, heterogeneous pulmonary hypertension-definitions and poorly reported timing of pulmonary hypertension assessments, however, data available in current reports are insufficient to allow accurate assessment of true prevalence, risk factors, and time-related outcome. Prospective studies, with standardised methodology and follow-up are needed to determine these factors.

Current and advancing treatments for pulmonary arterial hypertension in childhood

Pulmonary arterial hypertension (PAH) is a severe and progressive intrinsic disease of the precapillary lung vasculature. Since the introduction of PAH-targeted drugs, survival of PAH patients seems to have improved. Randomized controlled trials have led to evidence-based guidelines to direct treatment in adults. However, since disease characteristics differ between adults and children, it is hazardous to simply extrapolate these guidelines to children. Moreover, pediatric data on treatment strategies and how to assess treatment response remain virtually absent. Optimal treatment strategies are highly needed to guide therapy and improve survival in children with PAH. This review provides an overview of currently available treatments for PAH and the limited efficacy and safety data in children (with the exclusion of perinatal pulmonary vascular diseases, as persistent pulmonary hypertension of the newborn). We also discuss potential treatment goals and how the available data can be translated into treatment strategies in pediatric PAH.