Pulmonary thromboemboli after neonatal asphyxia

Neonatal and infant pulmonary thromboembolism: a literature review

Pulmonary thromboembolism (PTE) is rare in neonates and infants; however evidence suggests it is underdiagnosed. The primary objective is to conduct a scientific review to determine if the presentation, diagnosis, treatment and outcomes of neonates and infants with PTE are consistent across studies. Secondly, to develop an algorithm to establish the diagnosis and management of the condition based on current information. Two authors searched the literature independently using existing databases and verified that identical articles were assembled. Infants aged less than 1 year with PTE were included and further categorized into neonates 28 days or less and infants 29 days to 1 year or less. Forty-five articles with 157 cases (121 neonates; 36 infants) were identified with PTE. All of the reports were descriptive and neither randomized controlled trials nor prospective or case-control studies were identified. The reports are sub-classified into cases of pulmonary air embolism (PAE) with a higher mortality rate and patients with PTE. Diagnostic and treatment strategies varied widely and were individually case-based, dependent on clinical findings, which influenced patient outcomes. Scientific data to guide an evidence-based, diagnostic and treatment approach to PTE is limited because of the absence of rigorous clinical trials. Large scale, multicenter collaborative studies are required to firmly establish the management of PTE in this population.

Neonatal pulmonary artery thrombosis presenting as persistent pulmonary hypertension of the newborn

Pulmonary artery thrombosis in neonates occurs rarely. This report describes the case of a term infant with a pulmonary artery thrombosis presenting as persistent pulmonary hypertension of the newborn. The risk factors identified in the case included maternal diabetes and heterozygous factor V Leiden deficiency. The pulmonary thrombus was successfully treated with percutaneous catheter-based embolectomy.

Elevated immunoreactive endothelin-1 levels in newborn infants with persistent pulmonary hypertension

To study the potential role of endothelin-1, a potent endothelium-derived vasoconstrictor peptide, in the pathophysiology of persistent pulmonary hypertension of the newborn (PPHN), we measured arterial concentrations of immunoreactive endothelin-1 (irET-1) in 24 neonates with PPHN. Secondary diagnoses included meconium aspiration syndrome (13 patients), sepsis (2), congenital diaphragmatic hernia (1), asphyxia (1), pulmonary hemorrhage (1), aspiration of blood (1), and respiratory distress syndrome (1). Compared with irET-1 levels in umbilical cord blood in normal infants (15.1 +/- 4.1 pg/ml; mean +/- SEM) and in newborn infants with hyaline membrane disease who were supported by mechanical ventilation (11.8 +/- 1.2 pg/ml), infants with PPHN had markedly elevated circulating irET-1 levels (27.6 +/- 3.6 pg/ml; p < 0.01 vs cord blood, hyaline membrane disease). Infants with severe PPHN requiring extracorporeal membrane oxygenation (ECMO) therapy had higher irET-1 levels than infants with milder disease (31.0 +/- 4.7 for ECMO-treated infants vs 21.2 +/- 2.0 for non-ECMO-treated infants; p < 0.05). In patients treated without ECMO, irET-1 progressively decreased during the following 3 to 5 days, paralleling clinical improvement. In contrast, irET-1 concentrations remained elevated in infants with severe PPHN during ECMO therapy. We conclude that circulating irET-1 levels are elevated in newborn infants with PPHN, are positively correlated with disease severity, and decline with resolution of disease in patients who do not require ECMO therapy. Whether endothelin-1 contributes directly to the pathophysiology of PPHN or is simply a marker of disease activity remains speculative.