Anticoagulation-Free Pediatric Extracorporeal Membrane Oxygenation: Single-Center Retrospective Study.

OBJECTIVES: To analyze hemorrhage and thrombosis data related to anticoagulation-free pediatric extracorporeal membrane oxygenation (ECMO). DESIGN: Retrospective cohort study. SETTINGS: High-volume ECMO single institution data. PATIENTS: Children (0-18 yr) supported with ECMO (>24 hr) with initial anticoagulation-free period of greater than or equal to 6 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Utilizing consensus American Thoracic Society definitions for hemorrhage and thrombosis on ECMO, we evaluated thrombosis and associated patient and ECMO characteristics during anticoagulation-free period. Thirty-five patients met inclusion criteria from 2018 to 2021 having a median age (interquartile range [IQR]) of 13.5 months (IQR, 3-91 mo), median ECMO duration of 135 hours (IQR, 64-217 hr), and 964 anticoagulation-free hours. Increased RBC transfusion needs were associated with longer anticoagulation-free periods ( p = 0.03). We identified 20 thrombotic events: only four during the anticoagulation-free period and occurring in three of 35 (8%) patients. Compared with those without thrombotic events, anticoagulation-free clotting events were associated with younger age (i.e., 0.3 mo [IQR, 0.2-0.3 mo] vs 22.9 mo [IQR, 3.6-112.9 mo]; p = 0.02), lower weight (2.7 kg [IQR, 2.7-3.25 kg] vs 13.2 kg [5.9-36.4 kg]; p = 0.006), support with lower median ECMO flow rate (0.5 kg [IQR, 0.45-0.55 kg] vs 1.25 kg [IQR, 0.65-2.5 kg]; p = 0.04), and longer anticoagulation-free ECMO duration (44.5 hr [IQR, 40-85 hr] vs 17.6 hr [IQR, 13-24.1]; p = 0.008). CONCLUSIONS: In selected high-risk-for-bleeding patients, our experience is that we can use ECMO in our center for limited periods without systemic anticoagulation, with lower frequency of patient or circuit thrombosis. Larger multicentered studies are required to assess weight, age, ECMO flow, and anticoagulation-free time limitations that are likely to pose risk for thrombotic events.

The maternal-age-associated risk of congenital heart disease is modifiable.

Maternal age is a risk factor for congenital heart disease even in the absence of any chromosomal abnormality in the newborn. Whether the basis of this risk resides with the mother or oocyte is unknown. The impact of maternal age on congenital heart disease can be modelled in mouse pups that harbour a mutation of the cardiac transcription factor gene Nkx2-5 (ref. 8). Here, reciprocal ovarian transplants between young and old mothers establish a maternal basis for the age-associated risk in mice. A high-fat diet does not accelerate the effect of maternal ageing, so hyperglycaemia and obesity do not simply explain the mechanism. The age-associated risk varies with the mother's strain background, making it a quantitative genetic trait. Most remarkably, voluntary exercise, whether begun by mothers at a young age or later in life, can mitigate the risk when they are older. Thus, even when the offspring carry a causal mutation, an intervention aimed at the mother can meaningfully reduce their risk of congenital heart disease.

Nkx2-5 and Sarcospan genetically interact in the development of the muscular ventricular septum of the heart.

The muscular ventricular septum separates the flow of oxygenated and de-oxygenated blood in air-breathing vertebrates. Defects within it, termed muscular ventricular septal defects (VSDs), are common, yet less is known about how they arise than rarer heart defects. Mutations of the cardiac transcription factor NKX2-5 cause cardiac malformations, including muscular VSDs. We describe here a genetic interaction between Nkx2-5 and Sarcospan (Sspn) that affects the risk of muscular VSD in mice. Sspn encodes a protein in the dystrophin-glycoprotein complex. Sspn knockout (SspnKO) mice do not have heart defects, but Nkx2-5+/-/SspnKO mutants have a higher incidence of muscular VSD than Nkx2-5+/- mice. Myofibers in the ventricular septum follow a stereotypical pattern that is disrupted around a muscular VSD. Subendocardial myofibers normally run in parallel along the left ventricular outflow tract, but in the Nkx2-5+/-/SspnKO mutant they commonly deviate into the septum even in the absence of a muscular VSD. Thus, Nkx2-5 and Sspn act in a pathway that affects the alignment of myofibers during the development of the ventricular septum. The malalignment may be a consequence of a defect in the coalescence of trabeculae into the developing ventricular septum, which has been hypothesized to be the mechanistic basis of muscular VSDs.