[Bronchopulmonary dysplasia-associated pulmonary arterial hypertension of very preterm infants]

Assessing the role of tracheostomy placement in bronchopulmonary dysplasia with pulmonary hypertension

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth and is associated with abnormal vasculature that contributes to pulmonary hypertension (PH). We evaluated how a tracheostomy may alter PH in these patients.

METHODS

A retrospective chart review over 15-years identified 17 patients with BPD and PH who underwent tracheostomy. Each patient had four echocardiograms re-reviewed and scored for tricuspid valve regurgitation velocity (TR), tricuspid annular plane systolic excursion (TAPSE), right atrial cross-sectional area (RACA), and left ventricle eccentricity indices (EI).

RESULT

There was improvement in TR, TAPSE, RACA, and left ventricle EI indicating reduction in PH after tracheostomy.

CONCLUSION

PH improves over time though role of tracheostomy in PH needs to be further defined. The EI may be a sensitive marker to follow over time in these patients.

Pulmonary hypertension in the child with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of prematurity resulting from complex interactions of perinatal factors that often lead to prolonged respiratory support and increased pulmonary morbidity. There is also growing appreciation for the dysmorphic pulmonary bed characterized by vascular growth arrest and remodeling, resulting in pulmonary vascular disease and its most severe form, pulmonary hypertension (PH) in children with BPD. In this review, we comprehensively discuss the pathophysiology of PH in children with BPD, evaluate the current recommendations for screening and diagnosis of PH, discern associated comorbid conditions, and outline the current treatment options.

Chitin-Derived AVR-48 Prevents Experimental Bronchopulmonary Dysplasia (BPD) and BPD-Associated Pulmonary Hypertension in Newborn Mice

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity and a key contributor to the large health care burden associated with prematurity, longer hospital stays, higher hospital costs, and frequent re-hospitalizations of affected patients through the first year of life and increased resource utilization throughout childhood. This disease is associated with abnormal pulmonary function that may lead to BPD-associated pulmonary hypertension (PH), a major contributor to neonatal mortality and morbidity. In the absence of any definitive treatment options, this life-threatening disease is associated with high resource utilization during and after neonatal intensive care unit (NICU) stay. The goal of this study was to test the safety and efficacy of a small molecule derivative of chitin, AVR-48, as prophylactic therapy for preventing experimental BPD in a mouse model. Two doses of AVR-48 were delivered either intranasally (0.11 mg/kg), intraperitoneally (10 mg/kg), or intravenously (IV) (10 mg/kg) to newborn mouse pups on postnatal day (P)2 and P4. The outcomes were assessed by measuring total inflammatory cells in the broncho-alveolar lavage fluid (BALF), chord length, septal thickness, and radial alveolar counts of the alveoli, Fulton’s Index (for PH), cell proliferation and cell death by immunostaining, and markers of inflammation by Western blotting and ELISA. The bioavailability and safety of the drug were assessed by pharmacokinetic and toxicity studies in both neonatal mice and rat pups (P3-P5). Following AVR-48 treatment, alveolar simplification was improved, as evident from chord length, septal thickness, and radial alveolar counts; total inflammatory cells were decreased in the BALF; Fulton’s Index was decreased and lung inflammation and cell death were decreased, while angiogenesis and cell proliferation were increased. AVR-48 was found to be safe and the no-observed-adverse-effect level (NOAEL) in rat pups was determined to be 100 mg/kg when delivered via IV dosing with a 20-fold safety margin. With no reported toxicity and with a shorter half-life, AVR-48 is able to reverse the worsening cardiopulmonary phenotype of experimental BPD and BPD-PH, compared to controls, thus positioning it as a future drug candidate.

Pulmonary hypertension is an important co-morbidity in developmental lung diseases of infancy: Bronchopulmonary dysplasia and congenital diaphragmatic hernia

Bronchopulmonary dysplasia (BPD) following preterm birth and congenital diaphragmatic hernia (CDH) are both forms of developmental lung disease that may result in persistent pulmonary and pulmonary vascular morbidity in childhood. The pulmonary vascular disease (PVD) which accompanies BPD and CDH is due to developmental abnormalities and ongoing perinatal insults. This may be accompanied by evidence of elevated right heart pressures and pulmonary vascular resistance, leading to diagnosis of pulmonary hypertension (PH). The development of PH in these conditions is associated with increased morbidity and mortality in the vulnerable BPD and CDH populations. We present a review of PVD pathogenesis and evaluation in BPD and CDH and discuss management of related sequelae of PH co-morbidity for affected infants.

Risk Factors for Development of Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia: Systematic Review and Meta-Analysis

OBJECTIVES

Preterm infants with bronchopulmonary dysplasia (BPD) are at increased risk for development of Pulmonary Hypertension (PHT). We performed a systematic review and meta-analysis to identify risk factors for development of PHT in infants with BPD.

STUDY DESIGN

A systematic review identified risk factors for the development of PHT in infants with BPD. A meta-analysis of the pooled data was performed for each individual risk factor.

RESULT

Of the 20 risk factors identified, 10 were repeated more than once in nine studies. Meta analysis showed that duration of mechanical ventilation, length of stay, oligohydramnios, use of high frequency ventilation, small for gestational age, sepsis and severity of BPD were significant risk factors; while birth weight and gestational age were inversely related.

CONCLUSION

Several clinical variables are predictive of the development of PHT in infants with BPD. Prospective studies are needed to transform these risk factors into a risk-based scoring system.

Bronchopulmonary Dysplasia: Chronic Lung Disease of Infancy and Long-Term Pulmonary Outcomes

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly seen in premature infants who required mechanical ventilation and oxygen therapy for acute respiratory distress. While advances in neonatal care have resulted in improved survival rates of premature infants, limited progress has been made in reducing rates of BPD. Lack of progress may in part be attributed to the limited therapeutic options available for prevention and treatment of BPD. Several lung-protective strategies have been shown to reduce risks, including use of non-invasive support, as well as early extubation and volume ventilation when intubation is required. These approaches, along with optimal nutrition and medical therapy, decrease risk of BPD; however, impacts on long-term outcomes are poorly defined. Characterization of late outcomes remain a challenge as rapid advances in medical management result in current adult BPD survivors representing outdated neonatal care. While pulmonary disease improves with growth, long-term follow-up studies raise concerns for persistent pulmonary dysfunction; asthma-like symptoms and exercise intolerance in young adults after BPD. Abnormal ventilatory responses and pulmonary hypertension can further complicate disease. These pulmonary morbidities, combined with environmental and infectious exposures, may result in significant long-term pulmonary sequalae and represent a growing burden on health systems. Additional longitudinal studies are needed to determine outcomes beyond the second decade, and define risk factors and optimal treatment for late sequalae of disease.

Sildenafil, pulmonary hypertension and bronchopulmonary dysplasia

Pulmonary hypertension (PH) secondary to bronchopulmonary dysplasia (BPD) in infants remains a serious concern and continues to cause significant morbidity despite improvements in both quality of life and survival for patients. One of the potential agents that might help is sildenafil citrate, a phosphodiesterase-V inhibitor used a first line therapy for idiopathic PH. However, only limited evidence exists for its use as either monotherapy or part of a combination approach towards the management of PH in BPD. The evidence and current knowledge is presented for sildenafil alone and in combination with other disease modifying agents to treat PH in the presence of BPD. We have previously suggested that sildenafil appears to be safe and possibly effective in this condition. We present the evidence that if continued until PH resolution, there might be reduced mortality in this debilitating disease.

The utility of sildenafil in pulmonary hypertension: a focus on bronchopulmonary dysplasia

The treatment of pulmonary hypertension (PH) secondary to bronchopulmonary dysplasia (BPD) in infants has evolved in recent years, improving both quality of life and survival for patients. One of the potential agents for this condition is sildenafil, a phosphodiesterase-V inhibitor with proven efficacy within the idiopathic PH population. However, only limited evidence exists for its use as either monotherapy or part of a combination approach towards the management of PH in BPD. This review summarises the evidence base for sildenafil alone and in combination with other recognised therapeutic agents for ameliorating paediatric PH in the presence of BPD. It also examines the suitability for current practice with the aim of clarifying regimens that produce improved patient outcomes. We conclude that sildenafil is both safe and effective in this utility. Doses should be started at 0.5 mg/kg every 8 h before titrating up towards 2 mg/kg every 6 h to effect reductions in pulmonary vascular resistance and arterial pressure. Evidence suggests that if continued until PH resolution, this improves survival from 61% to 81% at 12 months. Furthermore, there are also data suggesting that in treatment refractory PH cases, the addition of endothelin antagonists and prostacyclin analogues to sildenafil therapy can also be considered.