Pediatric Pulmonary Hypertension: Guidelines From the American Heart Association and American Thoracic Society.

Pulmonary hypertension is associated with diverse cardiac, pulmonary, and systemic diseases in neonates, infants, and older children and contributes to significant morbidity and mortality. However, current approaches to caring for pediatric patients with pulmonary hypertension have been limited by the lack of consensus guidelines from experts in the field. In a joint effort from the American Heart Association and American Thoracic Society, a panel of experienced clinicians and clinician-scientists was assembled to review the current literature and to make recommendations on the diagnosis, evaluation, and treatment of pediatric pulmonary hypertension. This publication presents the results of extensive literature reviews, discussions, and formal scoring of recommendations for the care of children with pulmonary hypertension.

Long-term safety and efficacy of imatinib in pulmonary arterial hypertension.

BACKGROUND: Imatinib is an oral inhibitor of several protein kinases implicated in the pathophysiology of pulmonary hypertension. Treatment with imatinib resulted in improved hemodynamics and exercise capacity in a controlled trial (Imatinib [QTI571] in Pulmonary Arterial Hypertension, a Randomized Efficacy Study [IMPRES]), among pulmonary arterial hypertension (PAH) patients inadequately responsive to 2 to 3 PAH-specific therapies. METHODS: The long-term (up to 204 weeks) safety and efficacy of imatinib in this open-label extension study were reviewed until early study termination on April 16, 2014. Of 202 IMPRES-enrolled patients, 66 imatinib and 78 placebo recipients entered the extension. RESULTS: Overall, 93.8% (135 of 144) of patients discontinued the extension study; administrative issues (i.e., sponsor termination; 32.6%) and adverse events (31.3%) were the primary reasons for discontinuation. Nine patients completed the extension study before it was terminated. Serious and unexpected adverse events were frequent. These included 6 subdural hematomas in the extension study and 17 deaths during or within 30 days of study end. Although the patients who tolerated imatinib and remained in the extension for a longer duration did experience an improvement in functional class and walk distance, most discontinued the drug and the study. CONCLUSIONS: Severe adverse events, significant side effects, and a high discontinuation rate limit the utility of imatinib in the treatment of PAH. These risks outweigh any possible improvements in hemodynamics and walk distance seen in those patients able to remain on drug. The off-label use of this compound in PAH is discouraged.

Validation of two predictive models for survival in pulmonary arterial hypertension.

The French Pulmonary Hypertension Network (FPHN) registry and the Registry to Evaluate Early And Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL) have developed predictive models for survival in pulmonary arterial hypertension (PAH). In this collaboration, we assess the external validity (or generalisability) of the FPHN ItinérAIR-HTAP predictive equation and the REVEAL risk score calculator. Validation cohorts approximated the eligibility criteria defined for each model. The REVEAL cohort comprised 292 treatment-naïve, adult patients diagnosed <1 year prior to enrolment with idiopathic, familial or anorexigen-induced PAH. The FPHN cohort comprised 1737 patients with group 1 PAH. Application of FPHN parameters to REVEAL and REVEAL risk scores to FPHN demonstrated estimated hazard ratios that were consistent between studies and had high probabilities of concordance (hazard ratios of 0.72, 95% CI 0.64-0.80, and 0.73, 95% CI 0.70-0.77, respectively). The REVEAL risk score calculator and FPHN ItinérAIR-HTAP predictive equation showed good discrimination and calibration for prediction of survival in the FPHN and REVEAL cohorts, respectively, suggesting prognostic generalisability in geographically different PAH populations. Once prospectively validated, these may become valuable tools in clinical practice.

Effect of imatinib as add-on therapy on echocardiographic measures of right ventricular function in patients with significant pulmonary arterial hypertension.

AIMS: Imatinib mesylate, as add-on therapy in patients with pulmonary arterial hypertension (PAH) who remain inadequately treated despite receiving at least two PAH-specific drugs, improves exercise capacity and haemodynamics. We evaluated whether 24 weeks of add-on therapy with imatinib compared with placebo also improves right ventricular (RV) function assessed by echocardiography. METHODS AND RESULTS: Echocardiograms were obtained at baseline, 12 weeks, and 24 weeks in 74 patients randomized to imatinib or placebo in the Imatinib in Pulmonary arterial hypertension, a Randomized Efficacy Study (IMPRES) trial. Right ventricular function was assessed by tissue Doppler tricuspid annular peak systolic velocity (TA S'), tricuspid annular plane systolic excursion (TAPSE), RV Tei index, and RV fractional area change. Between-treatment-group differences in the changes from baseline to week-24 were assessed using an ANCOVA with the last observation carried forward. At week-24 patients randomized to imatinib demonstrated greater improvements in TA S' (1.6 ± 2.3 imatinib vs. 0.5 ± 2.4 cm/s placebo, P = 0.007) and RV Tei index (-0.11 ± 0.18 imatinib vs. 0.05 ± 0.18 placebo, P = 0.005) compared with placebo, but not in TAPSE (0.07 ± 0.44 imatinib vs. 0.03 ± 0.32 cm placebo, P = 0.08). Imatinib therapy was also associated with significant reduction in peak tricuspid regurgitation velocity, increase in LV size, and improvement in LV early diastolic relaxation velocity. CONCLUSIONS: Among patients with advanced PAH who remain symptomatic on at least two PAH-specific drugs, treatment with imatinib compared with placebo is associated with significant improvements in echocardiographic measures of RV function, in addition to LV size and LV early diastolic relaxation. CLINICAL TRIAL REGISTRATION: NCT00902174 (Clinicaltrials.gov).

Hospitalization and survival in patients using epoprostenol for injection in the PROSPECT observational study.

BACKGROUND: Few studies have prospectively reported outcomes in patients with pulmonary arterial hypertension (PAH) treated with epoprostenol in the modern-day era of oral therapy and combination treatments. The Registry to Prospectively Describe Use of Epoprostenol for Injection (Veletri, prolonged room temperature stable-epoprostenol [RTS-Epo]) in Patients with Pulmonary Arterial Hypertension (PROSPECT) was established to prospectively describe the course of PAH in patients prescribed RTS-Epo. METHODS: PROSPECT is a multicenter, US-based drug registry of primarily group 1 patients with PAH treated with RTS-Epo who were parenteral-naive or parenteral-transitioned at enrollment. Patients were followed until discontinuation of RTS-Epo, withdrawal, loss to follow-up, death, or end of study (maximum 1 year). One-year freedom from hospitalization (FH) and survival estimates were summarized by prostacyclin history (parenteral-naive or parenteral-transitioned), sex, and chronic renal insufficiency (CRI). RESULTS: A total of 336 patients were included. The overall 1-year FH estimate was 51.0% ± 2.8% and was lower in parenteral-naive patients than parenteral-transitioned patients (42.8% ± 4.3% vs 57.1% ± 3.7%, respectively; P = .002). FH estimates were lower in male patients than female patients (38.3% ± 5.9% vs 54.6% ± 3.2%, respectively; P < .015) and in patients with CRI than patients without CRI (17.0% ± 8.4% vs 53.7% ± 2.9%, respectively; P < .001). The overall 1-year survival estimate was 84.0% ± 2.1%. Survival was poorer in parenteral-naive patients, male patients, and patients with CRI. CONCLUSIONS: Risk of hospitalization and mortality remain high in patients with PAH. In particular, patients who are parenteral-naive at initiation of RTS-Epo therapy, male patients, and patients with CRI require close monitoring and aggressive clinical management.

Risk factors for death in 632 patients with sickle cell disease in the United States and United Kingdom.

BACKGROUND: The role of pulmonary hypertension as a cause of mortality in sickle cell disease (SCD) is controversial. METHODS AND RESULTS: We evaluated the relationship between an elevated estimated pulmonary artery systolic pressure and mortality in patients with SCD. We followed patients from the walk-PHaSST screening cohort for a median of 29 months. A tricuspid regurgitation velocity (TRV)≥ 3.0 m/s cuttof, which has a 67-75% positive predictive value for mean pulmonary artery pressure ≥ 25 mm Hg was used. Among 572 subjects, 11.2% had TRV ≥ 3.0 m/sec. Among 582 with a measured NT-proBNP, 24.1% had values ≥ 160 pg/mL. Of 22 deaths during follow-up, 50% had a TRV ≥ 3.0 m/sec. At 24 months the cumulative survival was 83% with TRV ≥ 3.0 m/sec and 98% with TRV < 3.0 m/sec (p < 0.0001). The hazard ratios for death were 11.1 (95% CI 4.1-30.1; p < 0.0001) for TRV ≥ 3.0 m/sec, 4.6 (1.8-11.3; p = 0.001) for NT-proBNP ≥ 160 pg/mL, and 14.9 (5.5-39.9; p < 0.0001) for both TRV ≥ 3.0 m/sec and NT-proBNP ≥ 160 pg/mL. Age > 47 years, male gender, chronic transfusions, WHO class III-IV, increased hemolytic markers, ferritin and creatinine were also associated with increased risk of death. CONCLUSIONS: A TRV ≥ 3.0 m/sec occurs in approximately 10% of individuals and has the highest risk for death of any measured variable. The study is registered in ClinicalTrials.gov with identifier: NCT00492531.

Repair of congenital heart disease with associated pulmonary hypertension in children: what are the minimal investigative procedures? Consensus statement from the Congenital Heart Disease and Pediatric Task Forces, Pulmonary Vascular Research Institute (PVRI).

Standardization of the diagnostic routine for children with congenital heart disease associated with pulmonary arterial hypertension (PAH-CHD) is crucial, in particular since inappropriate assignment to repair of the cardiac lesions (e.g., surgical repair in patients with elevated pulmonary vascular resistance) may be detrimental and associated with poor outcomes. Thus, members of the Congenital Heart Disease and Pediatric Task Forces of the Pulmonary Vascular Research Institute decided to conduct a survey aimed at collecting expert opinion from different institutions in several countries, covering many aspects of the management of PAH-CHD, from clinical recognition to noninvasive and invasive diagnostic procedures and immediate postoperative support. In privileged communities, the vast majority of children with congenital cardiac shunts are now treated early in life, on the basis of noninvasive diagnostic evaluation, and have an uneventful postoperative course, with no residual PAH. However, a small percentage of patients (older at presentation, with extracardiac syndromes or absence of clinical features of increased pulmonary blood flow, thus suggesting elevated pulmonary vascular resistance) remain at a higher risk of complications and unfavorable outcomes. These patients need a more sophisticated diagnostic approach, including invasive procedures. The authors emphasize that decision making regarding operability is based not only on cardiac catheterization data but also on the complete diagnostic picture, which includes the clinical history, physical examination, and all aspects of noninvasive evaluation.

Long-term sildenafil added to intravenous epoprostenol in patients with pulmonary arterial hypertension.

BACKGROUND: In pulmonary arterial hypertension (PAH), adding oral sildenafil to intravenous epoprostenol improved 6-minute walk distance (6MWD) and hemodynamics and delayed time to clinical worsening in a 16-week randomized, placebo-controlled trial (Pulmonary Arterial Hypertension Combination Study of Epoprostenol and Sildenafil [PACES-1]). METHODS: Patients completing PACES-1 could receive sildenafil (titrated to 80 mg, three times daily, as tolerated) in an open-label extension study (PACES-2) for ≥ 3 years; additional therapy was added according to investigator judgment. Survival and changes from PACES-1 baseline in World Health Organization Functional Class and 6MWD were captured. RESULTS: In an open-label setting, 6MWD, an effort-dependent outcome measure, was known to have improved or to have been maintained in 59%, 44%, and 33% of patients at 1, 2, and 3 years, respectively; functional class was known to have improved or to have been maintained in 73%, 59%, and 46%. At 3 years, 66% of patients were known to be alive, 24% were known to have died, and 10% were lost to follow-up. Patients with PACES-1 baseline 6MWD < 325 meters without 6MWD improvement during the first 20 weeks of sildenafil treatment subsequently had poorer survival. CONCLUSIONS: Although reliable assessments of safety and efficacy require a long-term randomized trial, the addition of sildenafil to background intravenous epoprostenol therapy appeared generally to be well tolerated in PAH patients.

STARTS-2: long-term survival with oral sildenafil monotherapy in treatment-naive pediatric pulmonary arterial hypertension.

BACKGROUND: The double-blind, placebo-controlled Sildenafil in Treatment-Naive Children, Aged 1 to 17 Years, With Pulmonary Arterial Hypertension (STARTS-1) study assessed sildenafil in pediatric patients with pulmonary arterial hypertension; improved hemodynamics and exercise capacity occurred in medium- and high-dose groups. STARTS-2 was the extension study. METHODS AND RESULTS: In STARTS-1, 234 children ≥8 kg were randomly assigned to low-, medium-, or high-dose sildenafil or placebo orally thrice daily; within-group dose depended on weight. In STARTS-2, sildenafil-treated patients continued STARTS-1 dosing; placebo-treated patients were randomized to 1 of the 3 sildenafil dose groups. Patients requiring additional pulmonary arterial hypertension-specific therapy discontinued study treatment; survival follow-up was attempted. As of August 2011, all children received ≥3 years of treatment (unless discontinued) from STARTS-1 baseline; 37 deaths were reported (26 on study treatment), 1 of which occurred within the first year of treatment. Most patients who died (28/37) had idiopathic/heritable pulmonary arterial hypertension (76% versus 33% overall) and baseline functional class III/IV disease (38% versus 15% overall); patients who died had worse baseline hemodynamics. Kaplan-Meier estimated 3-year survival rates from start of sildenafil were 94%, 93%, and 88% for patients randomized to low-, medium-, and high-dose sildenafil, respectively; 87%, 89%, and 80% were known to be alive at 3 years. Hazard ratios for mortality were 3.95 (95% confidence interval, 1.46-10.65) for high versus low and 1.92 (95% confidence interval, 0.65-5.65) for medium versus low dose; however, multiple analyses raised uncertainty about the survival/dose relationship. CONCLUSIONS: Although children randomized to higher compared with lower sildenafil doses had an unexplained increased mortality, all sildenafil dose groups displayed favorable survival for children with pulmonary arterial hypertension. CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov/ct2/show/NCT00159874 (extension study of NCT00149913). Unique identifier: NCT00159874.

An official American Thoracic Society clinical practice guideline: diagnosis, risk stratification, and management of pulmonary hypertension of sickle cell disease.

BACKGROUND: In adults with sickle cell disease (SCD), an increased tricuspid regurgitant velocity (TRV) measured by Doppler echocardiography, an increased serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) level, and pulmonary hypertension (PH) diagnosed by right heart catheterization (RHC) are independent risk factors for mortality. METHODS: A multidisciplinary committee was formed by clinician-investigators experienced in the management of patients with PH and/or SCD. Clinically important questions were posed, related evidence was appraised, and questions were answered with evidence-based recommendations. Target audiences include all clinicians who take care of patients with SCD. RESULTS: Mortality risk stratification guides decision making. An increased risk for mortality is defined as a TRV equal to or greater than 2.5 m/second, an NT-pro-BNP level equal to or greater than 160 pg/ml, or RHC-confirmed PH. For patients identified as having increased mortality risk, we make a strong recommendation for hydroxyurea as first-line therapy and a weak recommendation for chronic transfusions as an alternative therapy. For all patients with SCD with elevated TRV alone or elevated NT-pro-BNP alone, and for patients with SCD with RHC-confirmed PH with elevated pulmonary artery wedge pressure and low pulmonary vascular resistance, we make a strong recommendation against PAH-specific therapy. However, for select patients with SCD with RHC-confirmed PH who have elevated pulmonary vascular resistance and normal pulmonary capillary wedge pressure, we make a weak recommendation for either prostacyclin agonist or endothelin receptor antagonist therapy and a strong recommendation against phosphodiesterase-5 inhibitor therapy. CONCLUSIONS: Evidence-based recommendations for the management of patients with SCD with increased mortality risk are provided, but will require frequent reassessment and updating.

[New trial designs and potential therapies for pulmonary artery hypertension]. / Pulmoner arter hipertansiyonunda yeni çalisma tasarimlari ve potansiyel tedaviler.

A greater understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary artery hypertension (PAH) has led to significant advances, but the disease remains fatal. Treatment options are neither universally available nor always effective, underscoring the need for development of novel therapies and therapeutic strategies. Clinical trials to date have provided evidence of efficacy, but were limited in evaluating the scope and duration of treatment effects. Numerous potential targets in varied stages of drug development exist, in addition to novel uses of familiar therapies. The pursuit of gene and cell-based therapy continues, and device use to help acute deterioration and chronic management is emerging. This rapid surge of drug development has led to multicenter pivotal clinical trials and has resulted in novel ethical and global clinical trial I concerns. This paper will provide an overview of the opportunities and challenges that await the development of novel treatments for PAH. (J Am Coil Cardiol 2013;62:D82-91) ©2013 by the American College of Cardiology Foundation.

[Pediatric pulmonary hypertension]. / Pediyatrik pulmoner hipertansiyon.

Pulmonary hypertension (PH) is a rare disease in newborns, infants, and children that is associated with significant morbidity and mortality. In the majority of pediatric patients, PH is idiopathic or associated with congenital heart disease and rarely is associated with other conditions such as connective tissue or thromboembolic disease. Incidence data from the Netherlands has revealed an annual incidence and point prevalence of 0.7 and 4.4 for idiopathic pulmonary arterial hypertension and 2.2 and 15.6 for pulmonary arterial hypertension, respectively, associated with congenital heart disease (CHD) cases per million children. The updated Nice classification for PH has been enhanced to include a greater depth of CHD and emphasizes persistent PH of the newborn and developmental lung diseases, such as bronchopulmonary dysplasia and congenital diaphragmatic hernia. The management of pediatric PH remains challenging because treatment decisions continue to depend largely on results from evidence based adult studies and the clinical experience of pediatric experts. (J Am Coll Cardiol 2013;62:D117-26) ©2013 by the American College of Cardiology Foundation.

Four- and seven-year outcomes of patients with congenital heart disease-associated pulmonary arterial hypertension (from the REVEAL Registry).

Uncorrected congenital heart disease (CHD) frequently leads to pulmonary arterial hypertension (PAH), the most severe form of which is Eisenmenger syndrome (ES). We compared patients with idiopathic or heritable PAH (IPAH or HPAH; n = 1,626) against those with CHD-associated PAH (n = 353) who were enrolled in the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL Registry). Of patients with CHD-associated PAH, 151 had ES. Compared with the IPAH or HPAH cohort, the ES cohort had greater systemic blood flow (2 ± 1 vs 3 ± 2 L/min/m(2), p <0.001), lower mean right atrial pressure (10 ± 6 vs 7 ± 4 mm Hg, p <0.001), higher mean pulmonary artery pressure (53 ± 14 vs 65 ± 17 mm Hg, p <0.001), higher pulmonary vascular resistance index (22 ± 12 vs 32 ± 31 Wood units × m(2), p <0.001), and lower systemic arterial oxygen saturation at rest (92 ± 11% vs 84 ± 13%, p <0.001). At 4 years from enrollment and 7 years from diagnosis, survival rate was similar between IPAH or HPAH and CHD-associated PAH cohorts. For the overall CHD-associated PAH cohort, longer 6-minute walk distance, lower mean right atrial pressure, brain natriuretic peptide level <50 pg/ml, and the presence of acute vasoreactivity were predictors of survival at 4 years from enrollment; younger age and lower mean right atrial pressure were predictors of survival at 7 years from diagnosis. In conclusion, these observations support predicted physiologic differences (e.g., hemodynamics) between patients with IPAH or HPAH and patients with CHD-associated PAH, with or without a systemic-pulmonary shunt. These differences, however, did not translate into significantly improved 4- and 7-year survival rates in patients with ES versus IPAH or HPAH and CHD-associated PAH.

Repair of congenital heart disease with associated pulmonaryhypertension in children: what are the minimal investigativeprocedures? Consensus statement from the Congenital HeartDisease and Pediatric Task Forces, Pulmonary VascularResearch Institute (PVRI)

Standardization of the diagnostic routine for children with congenital heart disease associatedwith pulmonary arterial hypertension (PAH-CHD) is crucial, in particular since inappropriate assignmentto repair of the cardiac lesions (e.g., surgical repair in patients with elevated pulmonary vascular resistance)may be detrimental and associated with poor outcomes. Thus, members of the Congenital HeartDisease and Pediatric Task Forces of the Pulmonary Vascular Research Institute decided to conduct asurvey aimed at collecting expert opinion from different institutions in several countries, covering manyaspects of the management of PAH-CHD, from clinical recognition to noninvasive and invasive diagnosticprocedures and immediate postoperative support. In privileged communities, the vast majority of childrenwith congenital cardiac shunts are now treated early in life, on the basis of noninvasive diagnostic evaluation,and have an uneventful postoperative course, with no residual PAH. However, a small percentageof patients (older at presentation, with extracardiac syndromes or absence of clinical features of increasedpulmonary blood flow, thus suggesting elevated pulmonary vascular resistance) remain at a higher risk ofcomplications and unfavorable outcomes. These patients need a more sophisticated diagnostic approach,including invasive procedures. The authors emphasize that decision making regarding operability is basednot only on cardiac catheterization data but also on the complete diagnostic picture, which includes theclinical history, physical examination, and all aspects of noninvasive evaluation.

Pediatric pulmonary hypertension.

Pulmonary hypertension (PH) is a rare disease in newborns, infants, and children that is associated with significant morbidity and mortality. In the majority of pediatric patients, PH is idiopathic or associated with congenital heart disease and rarely is associated with other conditions such as connective tissue or thromboembolic disease. Incidence data from the Netherlands has revealed an annual incidence and point prevalence of 0.7 and 4.4 for idiopathic pulmonary arterial hypertension and 2.2 and 15.6 for pulmonary arterial hypertension, respectively, associated with congenital heart disease (CHD) cases per million children. The updated Nice classification for PH has been enhanced to include a greater depth of CHD and emphasizes persistent PH of the newborn and developmental lung diseases, such as bronchopulmonary dysplasia and congenital diaphragmatic hernia. The management of pediatric PH remains challenging because treatment decisions continue to depend largely on results from evidence-based adult studies and the clinical experience of pediatric experts.

New trial designs and potential therapies for pulmonary artery hypertension.

A greater understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary artery hypertension (PAH) has led to significant advances, but the disease remains fatal. Treatment options are neither universally available nor always effective, underscoring the need for development of novel therapies and therapeutic strategies. Clinical trials to date have provided evidence of efficacy, but were limited in evaluating the scope and duration of treatment effects. Numerous potential targets in varied stages of drug development exist, in addition to novel uses of familiar therapies. The pursuit of gene and cell-based therapy continues, and device use to help acute deterioration and chronic management is emerging. This rapid surge of drug development has led to multicenter pivotal clinical trials and has resulted in novel ethical and global clinical trial concerns. This paper will provide an overview of the opportunities and challenges that await the development of novel treatments for PAH.

One-year experience with intravenous treprostinil for pulmonary arterial hypertension.

BACKGROUND: Intravenous (IV) epoprostenol has been the mainstay of therapy in advanced pulmonary arterial hypertension (PAH). Continuous IV treprostinil has several potential advantages over IV epoprostenol; however, there has been a lack of published long-term efficacy and safety data on IV treprostinil in PAH. METHODS: We conducted a 48-week, multicenter, prospective, open-label, uncontrolled, study of continuous IV treprostinil in 16 patients on no prior PAH specific therapy at baseline (de novo), or 31 patients transitioned at baseline from IV epoprostenol (transition). The primary end point was change in exercise capacity assessed by the 6-minute walk distance (6MWD) test. RESULTS: In de novo patients, IV treprostinil increased the mean ± standard error 6MWD by 125 m from 332 ± 21 m at baseline to 457 ± 26 m at Week 48. There were also improvements in the secondary end points of Naughton-Balke treadmill time, Borg Dyspnea Score, and hemodynamics at Week 48 compared with baseline. In 23 patients transitioned from IV epoprostenol with 48-week follow-up data, 6MWD, hemodynamic measures, and World Health Organization functional class at Week 48 were all stable compared with baseline. Side effects were generally mild and consistent with those reported with prostacyclin treatment. During the study, 5 patients died of causes not considered related to the therapy, and 7 discontinued due to adverse events. CONCLUSIONS: In this open-label trial, continuous IV treprostinil for 1 year appears to be safe and effective in de novo PAH patients and those transitioned from IV epoprostenol.

Clinical trials in neonates and children: Report of the pulmonary hypertension academic research consortium pediatric advisory committee.

Drug trials in neonates and children with pulmonary hypertensive vascular disease pose unique but not insurmountable challenges. Childhood is defined by growth and development. Both may influence disease and outcomes of drug trials. The developing pulmonary vascular bed and airways may be subjected to maldevelopment, maladaptation, growth arrest, or dysregulation that influence the disease phenotype. Drug therapy is influenced by developmental changes in renal and hepatic blood flow, as well as in metabolic systems such as cytochrome P450. Drugs may affect children differently from adults, with different clearance, therapeutic levels and toxicities. Toxicity may not be manifested until the child reaches physical, endocrine and neurodevelopmental maturity. Adverse effects may be revealed in the next generation, should the development of ova or spermatozoa be affected. Consideration of safe, age-appropriate tablets and liquid formulations is an obvious but often neglected prerequisite to any pediatric drug trial. In designing a clinical trial, precise phenotyping and genotyping of disease is required to ensure appropriate and accurate inclusion and exclusion criteria. We need to explore physiologically based pharmacokinetic modeling and simulations together with statistical techniques to reduce sample size requirements. Clinical endpoints such as exercise capacity, using traditional classifications and testing cannot be applied routinely to children. Many lack the necessary neurodevelopmental skills and equipment may not be appropriate for use in children. Selection of endpoints appropriate to encompass the developmental spectrum from neonate to adolescent is particularly challenging. One possible solution is the development of composite outcome scores that include age and a developmentally specific functional classification, growth and development scores, exercise data, biomarkers and hemodynamics with repeated evaluation throughout the period of growth and development. In addition, although potentially costly, we recommend long-term continuation of blinded dose ranging after completion of the short-term, double-blind, placebo-controlled trial for side-effect surveillance, which should include neurodevelopmental and peripubertal monitoring. The search for robust evidence to guide safe therapy of children and neonates with pulmonary hypertensive vascular disease is a crucial and necessary goal.

Diagnostic evaluation of paediatric pulmonary hypertension in current clinical practice.

Current paediatric pulmonary hypertension (PH) diagnostic algorithms include some testing specifically for paediatrics, but it is unclear if this is used in clinical practice. We describe the current diagnostic workup of the TOPP (Tracking Outcomes and Practice in Paediatric Pulmonary hypertension) registry for suspected PH. We investigated 456 patients enrolled until February 2010. The majority had ECGs (94%), echocardiograms (96%) and/or chest radiographs (89%) performed and these were the noninvasive tests most frequently used for evaluation of suspected PH. No patient had all three tests considered normal, suggesting the potential for the combined use to rule out PH. For evaluation of complications associated with heart catheterisation (HC) we analysed a total of 908 HCs reported until February 2012. Of these, 554 were at diagnosis and 354 in follow-up. Complications were reported in 5.9% with five deaths considered related to HC, suggesting a higher rate of HC complications compared to adult studies. However, current recommendations support HC in paediatric PH. A proper application of the risk/benefit ratio for HC requires further data. Most children did not undergo the diagnostic workup currently recommended for adults, which highlights either incomplete awareness of current guidelines and/or challenges their appropriateness for children.