The Joint Outcome Study (JOS), a randomized controlled trial, demonstrated that children with severe hemophilia A (HA) initiating prophylactic factor VIII (FVIII) prior to age 2.5 years had reduced joint damage at age 6 years compared with those treated with episodic FVIII for bleeding. The Joint Outcome Continuation Study (JOS-C) evaluated early vs delayed prophylaxis effects on long-term joint health, following JOS participants to age 18 years in an observational, partially retrospective study. Index joint magnetic resonance imaging (MRI) scores of osteochondral (OC) damage (primary outcome), joint physical examination scores, and annualized rates of joint/other bleeding episodes (secondary outcomes) were collected. Thirty-seven of 65 JOS participants enrolled in JOS-C, including 15 randomized to prophylaxis at mean age 1.3 years (“early prophylaxis”); 18 initially randomized to episodic treatment, starting “delayed prophylaxis” at mean age 7.5 years; and 4 with high-titer inhibitors. At JOS-C exit, MRI OC damage was found in 77% of those on delayed and 35% of those on early prophylaxis for an odds ratio of OC damage, in the delayed vs early prophylaxis group, of 6.3 (95% confidence interval, 1.3, 29.9; P = .02). Annualized bleeding rates were higher with delayed prophylaxis (mean plus or minus standard deviation, 10.6 ± 6.6 vs 3.5 ± 2.1; P < .001), including when only comparing time periods on prophylaxis (6.2 ± 5.3 vs 3.3 ± 1.9; P < .05). In severe HA, early initiation of prophylaxis provided continued protection against joint damage throughout childhood compared with delayed initiation, but early prophylaxis was not sufficient to fully prevent damage. This trial was registered at www.clinicaltrials.gov as #NCT01000844.

Opacities, lucencies, and overall heterogeneity of lungs via quantitative CT can distinguish BPD patients from healthy controls, and these abnormalities decrease with age across BPD patients. Defining BPD severity by clinical outcomes such as respiratory support at several time points (vs a single time point, per current guidelines) may be meaningful.

Pulmonary embolism is an uncommon but potentially life-threatening event in children. There has been increasing awareness of pulmonary embolism in children with improved survival in children with systemic disease and advancements in diagnostic modalities. However, literature regarding pulmonary embolism in children is sparse, and thus current guidelines for management of pulmonary embolism in children are extrapolated from adult literature and remain controversial. This article reviews the background and pathophysiology of venous thromboembolism, as well as current diagnostic approach and recommended management of pulmonary embolism in children.

Background The use of quantitative CT analysis in children is limited by lack of normal values of lung parenchymal attenuation. These characteristics are important because normal lung development yields significant parenchymal attenuation changes as children age. Objective To perform quantitative characterization of normal pediatric lung parenchymal X-ray CT attenuation under routine clinical conditions in order to establish a baseline comparison to that seen in pathological lung conditions. Materials and methods We conducted a retrospective query of normal CT chest examinations in children ages 0–7 years from 2004 to 2014 using standard clinical protocol. During these examinations semi-automated lung parenchymal segmentation was performed to measure lung volume and mean lung attenuation. Results We analyzed 42 CT examinations in 39 children, ages 3 days to 83 months (mean ± standard deviation [SD] = 42±27 months). Lung volume ranged 0.10–1.72 liters (L). Mean lung attenuation was much higher in children younger than 12 months, with values as high as −380 Hounsfield units (HU) in neonates (lung volume 0.10 L). Lung volume decreased to approximately −650 HU by age 2 years (lung volume 0.47 L), with subsequently slower exponential decrease toward a relatively constant value of −860 HU as age and lung volume increased. Conclusion Normal lung parenchymal X-ray CT attenuation decreases with increasing lung volume and age; lung attenuation decreases rapidly in the first 2 years of age and more slowly thereafter. This change in normal lung attenuation should be taken into account as quantitative CT methods are translated to pediatric pulmonary imaging.

Background: The Joint Outcome Study (JOS) was a randomized controlled trial showing that, in severe hemophilia A, prophylactic factor VIII every other day starting prior to age 30 months leads to better joint outcomes at age 6 years than enhanced episodic treatment with factor VIII for bleeding1. After conclusion of the JOS, all participants were encouraged to continue on, or to transition to, prophylaxis. Here we describe the results of the Joint Outcome Continuation Study (JOS-C), which followed the participants of the JOS to age 18 years. Methods: All participants of the JOS were eligible for the JOS-C. MRIs of 6 index joints (right and left ankles, knees, and elbows), index joint physical exam scores using the Colorado Haemophilia Paediatric Joint Physical Examination Scale2 , estimates of joint bleeding episodes, and surgery information were collected. The primary endpoint, as in the initial JOS analysis, was evidence of hemophilia-related osteochondral joint damage on MRI, scored using the extended MRI scale3. Results: Of the 65 previous participants of the JOS, 37 gave informed consent for the JOS-C study, including 18 initially randomized to prophylaxis prior to age 30 months ("early prophylaxis"), and 19 initially randomized to enhanced episodic treatment who started prophylaxis at a mean age of 7.5 years (median 6.1, range 2.7-17.1, "delayed prophylaxis"). All initially on prophylaxis in the JOS continued on prophylaxis through the JOS-C. One participant (early prophylaxis arm) failed to complete an MRI, and four others (2 early and 2 delayed prophylaxis) had their MRIs excluded for technical reasons. Four participants (3 early prophylaxis and 1 delayed prophylaxis) developed high titer inhibitors during or shortly after the JOS and were analyzed separately. Osteochondral joint damage was defined as evidence of osteochondral damage on MRI or a need for joint surgery. The relative risk of osteochondral damage in those on delayed prophylaxis as compared to those on early prophylaxis was 6.5 (95% CI 1.3, 33.6; p=0.029). At age 18, 67% of those on early prophylaxis, and only 24% of those on delayed prophylaxis had zero index joints with osteochondral damage (Figure 1). Twenty-five percent of early prophylaxis and 47% of delayed prophylaxis participants had osteochondral damage to more than one joint. Most participants had some soft tissue changes on MRI, defined as effusion, synovial hypertrophy, or hemosiderin deposition. There was no difference in risk of soft tissue damage between initial treatment groups (p=0.48). Osteochondral damage scores were available for 3 patients with inhibitors: two with refractory inhibitors had osteochondral changes on at least one joint, and one with an inhibitor that tolerized within 3 months had no osteochondral damage. Total physical exam scores were also higher in the delayed prophylaxis arm (mean 22.6, standard deviation (SD) 15.5) than in the early prophylaxis arm (mean 16.2, SD 10.5), but this difference was not statistically significant (p=0.19). Conclusion: The JOS-C demonstrates that, in severe hemophilia A, initiation of prophylaxis prior to age 30 months provides continued protection against joint damage throughout childhood. Those who started on prophylaxis later in childhood had higher risk of joint damage at age 18. Initiation of factor VIII prophylaxis in the toddler years is critical to preventing osteochondral joint damage and should not be delayed. ReferencesManco-Johnson MJ, Abshire TC, Shapiro AD, et al. Prophylaxis versus episodic treatment to prevent joint disease in boys with severe hemophilia. N Engl J Med. 2007;357(6):535-544.Hacker MR, Funk SM, Manco-Johnson MJ. The Colorado Haemophilia Paediatric Joint Physical Examination Scale: normal values and interrater reliability. Haemophilia. 2007;13(1):71-78.Hong W, Raunig D, Lundin B. SPINART study: validation of the extended magnetic resonance imaging scale for evaluation of joint status in adult patients with severe haemophilia A using baseline data. Haemophilia. 2016;22(6):e519-e526. Figure 1: Percentage of participants with zero joints with osteochondral damage at JOS exit (age 6 years) and JOS-C exit (age 18 years), excluding participants with inhibitors. Disclosures Warren: Bayer Healthcare: Research Funding; HTRS/Novo Nordisk: Research Funding; Bayer Hemophilia Awards Program Fellowship Project Award: Research Funding; CSL Behring Heimburger Award: Research Funding. Shapiro:Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Prometic Life Sciences: Consultancy, Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Research Funding; Kedrion Biopharma: Consultancy, Research Funding; Bio Products Laboratory: Consultancy; Bioverativ, a Sanofi Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Healthcare: Other: International Network of Pediatric Hemophilia; Sangamo Biosciences: Consultancy; Octapharma: Research Funding; Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; OPKO: Research Funding; BioMarin: Research Funding. Recht:Shire: Research Funding; Biogen: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kedrion: Membership on an entity's Board of Directors or advisory committees. Manco-Johnson:Bayer AG: Honoraria, Research Funding; Novo Nordisk: Honoraria; Biogentek: Honoraria; CSL Behring: Honoraria; Baxalta, now part of Shire: Honoraria.