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No widely accepted method exists to evaluate pediatric hematology oncology patients for the risk of venous thromboembolism (VTE) and the need for prophylaxis. The use of a VTE risk-assessment tool and standardized guidelines for prophylaxis could increase the use of appropriate prophylaxis and reduce the number of VTEs in patients, thereby decreasing morbidity, mortality, hospitalization, and cost. The purpose of this project was to implement and assess the compliance of a pediatric-specific VTE risk-assessment tool in hospitalized pediatric, adolescent, and young adult hematology oncology patients. From the 114 pediatric, adolescent, and young adult patients requiring assessment, 91 (80%) VTE assessments were completed and 87 (96%) were completed accurately. Eighty percent of the at-risk patients were ordered VTE prophylaxis. The use of a VTE risk-assessment tool in pediatric hematology oncology patients is a feasible way to assess patients for their risk of developing a VTE.

Children with sickle cell anemia (SS) have an increased risk for cerebral vasculopathy with stroke (CVA) and cognitive impairment. The present study examines the extent to which adding positron emission tomography (PET) to magnetic resonance imaging (MRI) can improve the detection of cerebral vasculopathy. Whereas MRI has been the prime modality for showing anatomical lesions, PET excels at assessing the functional metabolic state through glucose utilization 2-deoxy-2 [18F] fluoro-D-glucose (FDG) and microvascular blood flow ([15O]H2O). Forty-nine SS children were studied. Among them, 19 had clinically overt CVA, 20 had life-threatening hypoxic episodes or soft neurologic signs, and 10 were normal based on neurological history and examination. For the entire sample of 49 subjects, 30 (61%) had abnormal MRI findings, 36 (73%) had abnormal PET findings, and 44 (90%) showed abnormalities on either the MRI or the PET or both. Of the 19 subjects with overt CVA, 17 had abnormal MRI (89%), 17 had abnormal PET (89%), and 19 (100%) had either abnormal MRI or PET or both. Among the 20 subjects with soft neurologic signs, 10 (50%) had abnormal MRI, 13 (65%) had abnormal PET, and 17 (85%) had abnormal MRI and/or PET. Six (60%) of the 10 neurologically normal subjects had abnormal PET. Among the 30 subjects with no overt CVA, 25 (83%) demonstrated imaging abnormalities based on either MRI or PET or both, thus, silent ischemia. Lower than average full-scale intelligence quotient (FSIQ) was associated with either overt CVA or silent ischemic lesions. Four subjects who received chronic red blood cell transfusion showed improved metabolic and perfusion status on repeat PET scans. In conclusion, (1) the addition of PET to MRI identified a much greater proportion of SS children with neuroimaging abnormalities, particularly in those who had no history of overt neurologic events. (2) PET lesions are more extensive, often bihemispheric, as compared with MRI abnormalities. (3) PET may be useful in management as a tool to evaluate metabolic improvement after therapeutic interventions, and (4) the correlation of PET abnormalities to subsequent stroke or progressive neurologic dysfunction requires further study.

In vivoneulrophil phagocytosis was demonstrated by transmission electron microscopy (TEM) in the peripheral blood of two half-sibs with hereditary thrombocylopenia. These sibs have had a lifetime documented history of thrombocytopenia. Light microscopy morphology and histochemistry studies of blood and marrow were normal, similar studies of blood from available members of the kinship were also normal. Scanning electron microscopy (SEM) of platelets from each member of the kinship showed normal dendritic and spreading formation. In the TKM thin sections of platelet huffy coats, neutrophil ingestion of platelets was common and all stages of the phagocytic process were noted—from plalelel-neutrophil intimacy to the formation of myelin bodies in phagosomes. The clinical courses over a 10-year period were mild, requiring rare therapeutic interventions. The chronic thrombocytopenia, lengthy mild course, modestly elevated platelet-associated immune globulin, normal aggregation and survival studies, and autoimmune neulrophil reaction to platelets allowed classification of these patients as hereditary thrombocytopenia purpuras.

From mid-1967 to mid-1983, three hundred fifty surgical operations were performed on 163 patients with hemophilia A, without factor VIII inhibitor. One death occurred, in a patient with a serious head injury. Postoperative hemorrhages occurred after 23% of operations, but the incidence after surgery on the knee, 40%, was decidedly higher than the 15% incidence after operations at other sites. Concurrent plasma factor VIII levels were over 0.40 units/mL in 72% of instances and under 0.30 units/mL in only 15% of instances. The incidence of postoperative hemorrhage did not change over the study period despite a threefold increase in typical dosage of factor VIII (from 600 to 2,000 units/kg per operation) and doubling of typical trough factor VIII levels (from 0.37 units/mL to 0.70 units/mL). Circulating factor VIII levels apparently are not the sole determinants of postoperative bleeding in hemophilia A.(JAMA 1985;253:1279-1283)

Gilbert score changes were small, and limited to the ankles, knees, and elbows. Group 2 had the highest overall bleeding score. Of the exploratory variables, Group 3 usually had numerically worse values than the other groups. For the HAL, Group 2 had a higher increase overall than Group 1. The STAI showed an increase in trait anxiety for Groups 1 and 2 during the study, and increase in state anxiety for group 1 but a decrease for Group 2. No other distinguishing findings emerged.Although the primary and main secondary efficacy variables showed clear benefits of continuing prophylaxis, the remaining secondary variables and the exploratory variables did not clearly distinguish between Groups 1 and 2, although most showed worse results for Group 3. For these variables the changes in Groups 1and 2 were usually small, occurred in a similar pattern in both groups, or showed inconsistent patterns. The changes in Group 3 suggest that quality of life decreases with length of time off prophylaxis. Small cell numbers, outliers, being in a clinical trial and questionnaire fatigue may be contributing factors.Manco-Johnson: Octapharma AG: Consultancy; Bayer: Research Funding. Ewing:CSL Behring: Consultancy, Honoraria, Research Funding, Travel funds; Baxter: Consultancy, Honoraria, Research Funding, Travel funds; Bayer: Consultancy, Honoraria, Research Funding, Travel funds; Biogen Idec: Consultancy, Honoraria, Research Funding, Travel funds; Grifols: Consultancy, Honoraria, Research Funding, Travel funds; Inspiration: Consultancy, Honoraria, Research Funding, Travel funds; NovoNordisk: Consultancy, Honoraria, Research Funding, Travel funds; Octapharma: Consultancy, Honoraria, Research Funding, Travel funds; Pfizer: Consultancy, Honoraria, Research Funding, Travel funds; Talecris: Consultancy, Honoraria, Research Funding, Travel funds. Humphries:Bayer: Employment.

Zieger: CSL Behring Hattersheim: Research Funding.

Development of inhibitors to human FVIII (hFVIII) is a significant complication in the reversal and prevention of bleeding events in hemophilia A patients. Porcine FVIII (pFVIII) possesses low cross reactivity to anti-hFVIII antibodies. OBI-1, a recombinant B-domain deleted pFVIII, has recently been tested in a Phase II trial in patients with congenital hemophilia A and inhibitors experiencing a non-life/non-limb threatening bleed. In patients with a measurable anti-pFVIII antibody titer, dosing was initiated with a loading dose (LD) followed by up to 8 doses of 50 to 150 U/kg of OBI-1 administered at 6 hour intervals until the bleed was controlled. The PK profile of OBI-1 was assessed for the first OBI-1 infusion of each patient. FVIII levels were measured 30 minutes after each infusion. Inhibitor titers were evaluated for a minimum of 6 months after the first OBI-1 infusion. A total of 25 bleeding episodes in 9 patients were treated successfully with OBI-1. The median time from bleeding onset to treatment was 7 hours (range: 3 20 hr). OBI-1 showed a cumulative efficacy of 72% after 1 injection, 84% after 2 injections or less, 92% after 3 injections or less, and 100% after 8 or less injections. In over 40 infusions, OBI-1 was well tolerated and no drug related SAEs were observed. One case of pruritus rated as mild was easily controlled with diphenhydramine. FVIII levels measured 30 minutes after each OBI-1 infusion ranged from < 0.5% to 226%. They were generally lower with higher anti-pFVIII titers although all bleeds were successfully controlled. Follow up inhibitor titers are still being monitored and final results will be presented and discussed. Other investigative parameters, including vital signs and laboratory variables did not show treatment related abnormalities. OBI-1 can be given as a short infusion. It was effective in controlling all bleeds which occurred in this study and was well tolerated. The results suggest that a LD is not needed with OBI-1 treatment, and in some instances patients may have been over treated. Given the promising results in this study, additional studies are planned to optimize dose range for OBI-1 and to confirm the long term safety and efficacy of OBI-1 in the treatment of bleeds in a larger cohort of individuals with hemophilia A complicated by the presence of hFVIII inhibitors.