Summary Introduction Developmental hemostasis recognizes the physiologic differences between the hemostatic system of neonates and children and that of adults. As compared with the knowledge of hemostatic system physiology in adults, our understanding in neonates and children remains inadequate. Routine clinical coagulation testing most commonly measures functional parameters of the hemostatic system. Very few studies have measured age‐specific levels of hemostatic proteins. An understanding of the normal fluctuations in the levels of hemostatic proteins is vital in the prevention, diagnosis and treatment of hemostatic problems during infancy and childhood. This study was designed as the first comprehensive study of the age‐specific changes in the levels of important hemostatic proteins in healthy neonates, children, and adults. Methods Plasma samples were obtained from 120 healthy individuals from the following age groups: neonates (day 1 and day 3), 28 days to 1 year, 1–5 years, 6–10 years, 11–16 years, and adults. Factor II, FV, FVII, FVIII, FIX, FX, FXI, FXII, FXIII, plasminogen, protein C and total and free protein S were quantified with commercially available ELISA kits. Results The levels of 10 proteins were significantly different between neonates and adults, and these differences persisted throughout childhood for most of these proteins. Conclusion The results of this study confirm that the levels of the majority of coagulation proteins vary significantly with age. Future studies should investigate how hemostatic protein level relates to functional changes with age.
Background We sought to characterize body composition abnormalities in young patients living with a Fontan circulation and explore potential pathophysiologic associations. Methods and Results Twenty‐eight patients with a Fontan circulation were prospectively recruited in this cross‐sectional study. Participants underwent cardiopulmonary exercise testing, dual‐energy X‐ray absorptiometry, echocardiography, and biochemical assessment. Mean age was 26±7 years. Skeletal muscle mass, estimated by appendicular lean mass index Z score, was reduced compared with reference data (−1.49±1.10, P <0.001). Percentage body fat Z score overall was within normal range (0.23±1.26, P =0.35), although 46% had elevated adiposity. Those with reduced skeletal muscle mass ( appendicular lean mass index Z score of −1 or lower) had lower percent predicted oxygen pulse (55±15 versus 76±16%, P =0.002). Overall agreement between body mass index and dual‐energy X‐ray absorptiometry to assess adiposity was fair only (weighted [linear] κ coefficient: 0.53; 95% CI , 0.34–0.73) and slight in the setting of muscle mass deficiency (weighted κ coefficient: 0.32; 95% CI , 0.13–0.50). Appendicular lean mass was independently associated with absolute peak VO 2 (β=70.6 mL /min, P =0.001). A ppendicular lean mass index Z score was inversely associated with hemoglobin ( r =−0.4, P =0.04), and the degree of muscle deficit was associated with ventricular systolic impairment. Conclusions Young patients with a Fontan circulation have a body composition characterized by reduced skeletal muscle mass, which is associated with peak exercise capacity. Increased adiposity is common despite a normal body mass index. Low skeletal muscle mass is associated with systolic dysfunction and compensatory erythrocytosis.
Background: Neurocognitive outcomes beyond childhood in people with a Fontan circulation are not well-defined. This study aimed to investigate neurocognitive functioning in adolescents and adults with a Fontan circulation and associations with structural brain injury, brain volumetry and post-natal clinical factors. Methods: In a bi-national study, participants with a Fontan circulation without a pre-existing major neurological disability were prospectively recruited from the Australia and New Zealand Fontan Registry. Neurocognitive function was assessed using Cogstate software in 107 Fontan-participants and compared with control groups with transposition of the great arteries (TGA; n=50) and a normal circulation (n=41). Brain MRI with volumetric analysis was performed in the Fontan-participants and compared with healthy control data from the ABIDE I and II and PING data repositories. Clinical data were retrospectively collected. Results: Of the Fontan-participants with neurocognitive assessment, 55% were male and the mean age was 22.6 years (SD 7.8). Fontan-participants performed worse in several areas of neurocognitive function compared with those with TGA and healthy controls (p<0.05). Clinical factors associated with worse neurocognitive outcomes included more inpatient days during childhood, younger age at Fontan and longer time since Fontan procedure (p<0.05). Fontan-adults had more marked neurocognitive dysfunction than Fontan-adolescents in two domains (psychomotor function, p=0.01 and working memory, p=0.02). Structural brain injury was present in the entire Fontan cohort; presence of white matter injury was associated with worse paired associate learning (p<0.001), but neither the presence or severity of infarct, subcortical grey matter injury and microhemorrhage was associated with neurocognitive outcomes. Compared with healthy controls, people with a Fontan circulation had smaller global brain volumes (p<0.001 in all regions) and smaller regional brain volumes in the majority of cerebral cortical regions (p<0.05). Smaller global brain volumes were associated with worse neurocognitive functioning in several domains (p<0.05). A significant positive association was also identified between global brain volumes and resting oxygen saturations (p≤0.04). Conclusions: Neurocognitive impairment is common in adolescents and adults with a Fontan circulation and is associated with smaller grey and white matter brain volume. Understanding modifiable factors that contribute to brain injury to optimize neurocognitive function is paramount.
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