Reliability of progressive and additive MRI scoring systems for evaluation of haemophilic arthropathy in children: expert MRI Working Group of the International Prophylaxis Study Group.

Effective treatment of haemophilic arthropathy requires a detailed evaluation of joint integrity. Methodological assessment of magnetic resonance imaging (MRI) scores are needed to assure reproducibility of measurements when comparing results of clinical trials conducted in different centres. We compared the reliability of two MRI scoring systems for assessment of haemophilic arthropathy: one progressive system that displays the most severe change and one additive system that depicts osteochondral and soft tissue-related changes. A total of 47 1.5 T MRI examinations of knees (n = 21) and ankles (n = 26) of 42 haemophilic boys, age range, 22 months to 18 years, performed at different centres (Toronto, n = 20, Europe, n = 12 and Denver, n = 15) were independently reviewed by four radiologists at two occasions. Twenty-two examinations were from children <9 years and 25 from children >/=9. Sagittal and coronal gradient-echo (MPGR, 3D FLASH with fat saturation, GRASS) images were obtained. The MRI examinations of the ankle and knee studies presented with osteochondral abnormalities in 38.5% and 23.8% of the cases respectively. The two scoring systems demonstrated an excellent inter-reader [progressive, 0.88; additive (A, e, s and h components), 0.86] and intra-reader [progressive, 0.92; additive (A, e, s and h components), 0.93] reliability using intraclass correlation coefficients (ICCs). Although ICCs were slightly higher for knees when compared with ankles, and for older children when compared with younger children, all values fell within excellent inter- and intra-reader reliability categories. The two MRI scoring systems demonstrated a comparable reliability. This result constitutes the basis for further development of a combined MRI scoring system for assessment of haemophilic arthropathy, which incorporates progressive and additive components.

Compatible scales for progressive and additive MRI assessments of haemophilic arthropathy.

The international MRI expert subgroup of the International Prophylaxis Study Group (IPSG) has developed a consensus for magnetic resonance imaging (MRI) scales for assessment of haemophilic arthropathy. A MRI scoring scheme including a 10 step progressive scale and a 20 step additive scale with identical definitions of mutual steps is presented. Using the progressive scale, effusion/haemarthrosis can correspond to progressive scores of 1, 2, or 3, and synovial hypertrophy and/or haemosiderin deposition to 4, 5, or 6. The progressive score can be 7 or 8 if there are subchondral cysts and/or surface erosions, and it is 9 or 10 if there is loss of cartilage. Using the additive scale, synovial hypertrophy contributes 1-3 points to the additive score and haemosiderin deposition contributes 1 point. For osteochondral changes, 16 statements are evaluated as to whether they are true or false, and each true statement contributes 1 point to the additive score. The use of these two compatible scales for progressive and additive MRI assessments can facilitate international comparison of data and enhance the accumulation of experience on MRI scoring of haemophilic arthropathy.

Physical therapy and imaging outcome measures in a haemophilia population treated with factor prophylaxis: current status and future directions.

Routine infusions of factor VIII to prevent bleeding, known as prophylaxis, and other intensive therapies are being more broadly applied to patients with haemophilia. These therapies differ widely in replacement product usage, cost, frequency of venous access and parental effort. In order to address residual issues relating to recommendations, implementation, and evaluations of prophylaxis therapy in persons with haemophila, a multinational working group was formed and called the International Prophylaxis Study Group (IPSG). The group was comprised of haemophilia treaters actively involved in studies of prophylaxis from North America and Europe. Two expert committees, the Physical Therapy (PT) Working Group and the Magnetic Resonance Imaging (MRI) Working Group were organized to critically assess existing tools for assessment of joint outcome. These two committees independently concluded that the WFH Physical Examination Scale (WFH PE Scale) and the WFH X-ray Scale (WFH XR Scale) were inadequately sensitive to detect early changes in joints. New scales were developed based on suggested modifications of the existing scales and called the Haemophilia Joint Health Score (HJHS) and the International MRI Scales. The new scales were piloted. Concordance was measured by the intra-class correlation coefficient of variation. Reliability of the HJHS was excellent with an inter-observer co-efficient of 0.83 and a test-retest value of 0.89. The MRI study was conducted using both Denver and European scoring approaches; inter-reader reliability using the two approaches was 0.88 and 0.87; test-retest reliability was 0.92 and 0.93. These new PT and MRI scales promise to improve outcome assessment in children on early preventive treatment regimens.

A common mutation, Arg457-->Gln, links prothrombin deficiencies in the Puerto Rican population.

Five unrelated families with Puerto Rican ancestry were identified as having at least one member with bleeding due to a prothrombin deficiency. Genetic prothrombin deficiencies are extremely rare, but at the University of Puerto Rico Hemophilia Center, prothrombin deficiency is the third most common congenital coagulation factor deficiency. Because Puerto Rico is relatively isolated, there was a reasonable expectation of a founder effect. Prothrombin genes from probands and their parents were directly sequenced from PCR amplified exons using forward and reverse primers. Four novel prothrombin mutations were identified. The first, a G-->A substitution at DNA position 10150 predicting an Arg457-->Gln (R457Q) replacement, is common to all five families. In two of the families, the proband children are homozygous for R457Q. In the other three families, the probands are compound heterozygotes for R457Q and one of the other three mutations, which include another point mutation (gamma16Q), a deletion and a splice junction mutation. The two point mutations have been designated Puerto Rico I and Puerto Rico II. The crystal structure of alpha-thrombin predicts that the R457Q mutation removes a salt bridge that links the A- and B-chains of thrombin. The primary effect of this defect appears to be destabilization of the circulating prothrombin, creating a moderate hypoprothrombinemia. However, prothrombin antigen/activity ratios indicate a dysprothrombinemia as well, most likely due to the inability of R457Q prothrombin to activate fully to thrombin.

Radiological assessment of haemophilic arthropathy with emphasis on MRI findings.

Medical imaging of haemophilic joints is important for detecting abnormalities, grading their severity and selecting the appropriate therapy. The plain-film scoring systems for staging joint disease that were developed prior to the availability of magnetic resonance imaging (MRI) are inadequate for planning modern prevention and treatment. MRI is capable of delineating all of the soft tissue findings long before they are evident on plain radiographs. In this paper, an MRI scoring system is presented along with examples of joint effusion, haemarthrosis, synovial hypertrophy, haemosiderin deposition, erosions, cysts and cartilage loss. MRI is a powerful tool in the diagnosis, staging and treatment of patients with haemophilic joint disease.

Factor IX Denver, ASN 346-->ASP mutation resulting in a dysfunctional protein with defective factor VIIIa interaction.

Hemophilia B is a sex-linked recessive bleeding disorder characterized by the presence of either a decreased amount of normal factor IX (FIX) or the presence of a dysfunctional FIX. We have identified a unique mutation in a family with mild hemophilia B. DNA analysis of family members revealed a single base transition in the 8th exon of the FIX gene predicting an amino acid change of Asn 346-->Asp in the catalytic domain. The FIX variant, named FIX Denver, was purified from proband plasma. Kinetic studies of factor X (FX) interactions with normal FIXa or FIXa Denver and phospholipid (PL) showed little difference in kcat but a significant difference when factor VIIIa (FVIIIa) was included in the reaction. Using kinetic assays to infer the Kd of FIXa for FVIIIa, normal FIXa had a Kd of 0.095 nM while that of FIXa Denver was 9.85 nM. The major defect caused by this point mutation is a marked decrease in the affinity of FIXa Denver for factor VIIIa.

Changes in the occurrence of and risk factors for hemophilia-associated intracranial hemorrhage.

Recent studies suggest that rates of intracranial hemorrhage (ICH) increased concomitant with the HIV epidemic among the hemophilia population, but no studies have directly examined factors associated with ICH. To determine ICH rates and identify factors associated with ICH, we performed a nested case-control study of a cohort composed of all hemophilic males identified by a surveillance system. Data were obtained from medical records of care received during 1993-1997. Patients with ICH listed in hospital records or on death certificates during the 5-year period were compared to the remainder of the cohort to examine associations between ICH and patients' demographic and clinical factors including the presence of HIV infection. Among the 3,269 males in the cohort, 88 (2.7%) had an ICH during follow-up, an average incidence rate of 0.0054 case/year. Hemorrhage sites were intracerebral for 37.5%, subdural for 34.1%, unspecified for 19.3%, subarachnoid for 12.5%, and epidural for 8% of cases. For 22% of cases, the ICH was trauma-related, and, overall, 16 patients (18.2%) died. Several factors were independently associated with ICH (odds ratio, P value): severe disease (2.0, 0.05); age 51+ years compared to 6-10 year olds (3.7, 0.02); presence of an inhibitor (3.5, <0.001); and HIV infection among whites only (4.0, <0.001). ICH rates in our cohort were 2-fold higher compared to rates from previous reports. Much of the increase was attributed to HIV infection, which raised ICH risk primarily in whites and was frequently associated with spontaneous ICH among older individuals. Published 2001 Wiley-Liss, Inc.

The varicella-autoantibody syndrome.

This cross-sectional study was conducted to determine the incidence of autoantibodies to phospholipids and coagulation proteins in children with acute varicella zoster virus (VZV) infection. Study groups included children with VZV alone or complicated by purpura fulminans and/or thromboembolism. VZV naïve children and children who had VZV >1 y before sample collection formed a control group. Blood was assayed for the following: free protein S (PS), protein C, antithrombin, and prothrombin; antibody binding to these proteins; lupus anticoagulant; anticardiolipin antibody; antiphospholipid antibodies; and prothrombin fragment 1+2. Data regarding coinfections was collected. Forty-three VZV-infected children showed an increased frequency of lupus anticoagulant, anticardiolipin antibody, antiphospholipid antibodies, and autoantibodies to PS, protein C, prothrombin, and antithrombin in comparison to 52 children without acute VZV (p < 0.0001). Seventeen children with VZV and purpura fulminans and/or thromboembolism showed a statistically significant decrease in free PS, significantly increased PS IgG antibody, and significantly increased prothrombin fragment 1+2 (p < 0.0001) compared with the group without acute VZV and the group with uncomplicated VZV. Twenty-six children with uncomplicated VZV showed increased PS IgG antibody (p < 0.001) compared with the children without acute VZV. For all groups combined, elevated PS IgG antibody showed negative correlation with free PS (p < 0.0001) and positive correlation with prothrombin fragment 1+2 (p = 0.0002). Autoantibodies were transient. Transient antiphospholipid and coagulation protein autoantibodies were common with VZV infection, but were not predictive of thrombotic complications.

Joint evaluation instruments for children and adults with haemophilia.

With the heightened interest in protocols to prevent or treat complications of haemophilia related to recurrent haemarthroses, there is a need for sensitive joint-evaluation tools. The World Federation of Haemophilia (WFH) Physical Joint Examination instrument, which was developed for persons with haemophilia worldwide, is not sensitive enough to detect early structural or functional abnormalities. Therefore, we have expanded the WFH instrument to detect more subtle abnormalities of joint structure and function, and in addition, developed a new scale specifically tailored to the dynamic growth and gait development of children. We compared the original and three new instruments in 43 children with haemophilia. The three new scales all showed better correlation with the WFH pain instrument than did the original WFH physical examination instrument (P < 0.01 for each of the new instruments vs. P > 0.05 for the WFH instrument). In addition, results of the new child physical examination instrument best conformed to a normal distribution (P=0.35) and this instrument had better overall statistical performance. This instrument should be studied further in prospective, longitudinal clinical trials of young children.

Late clinical, plain X-ray and magnetic resonance imaging findings in haemophilic joints treated with radiosynoviorthesis.

The clinical, plain X-ray and magnetic resonance imaging (MRI) findings were studied in 13 haemophilic joints previously treated with radiosynoviorthesis. (32)P had been injected into the joints at a median of 16 years earlier in an attempt to halt recurrent haemorrhage. Prior to (32)P injection, the majority of joints demonstrated bone damage evident on plain X-ray, secondary to recurrent haemorrhage. At the follow-up evaluation we found plain X-rays were adequate to identify cysts, erosions and cartilage loss in these very damaged joints. MRI was superior to clinical examination and plain X-ray in identifying synovial hyperplasia and effusions.

Unusual complications of warfarin therapy: skin necrosis and priapism.

Skin necrosis and priapism are unusual complications of warfarin therapy. We report a teenager with warfarin-associated skin necrosis and priapism who was subsequently found to be a compound heterozygote for protein C deficiency and a heterozygote for the factor V Leiden mutation.

Mortality among males with hemophilia: relations with source of medical care. The Hemophilia Surveillance System Project Investigators.

Although persons with hemophilia are known to be at increased risk of death, no studies have examined the source of medical care and other personal characteristics for associations with mortality. To determine death rates and to identify causes of death and predictors of mortality, we studied a cohort comprised of all hemophilic males identified by a six-state surveillance system. Data were obtained by medical record review of contacts with physicians, hemophilia treatment centers (HTCs), and other sources of care during 1993-1995 and from death certificates. Factors examined included age, race, state of residence, health insurance type, medical care source, hemophilia type/severity, presence of inhibitor, liver disease, HIV infection, and AIDS. A total of 2950 subjects were followed for an average of 2.6 years. Their median age was 22 years; 73% were white, 79% had hemophilia A, 42% had severe disease, and 67% had visited an HTC. During 7575 person years (PYs) of observation, 236 persons died-an age-adjusted mortality rate of 40.4 deaths/1000 PYs; 65% of deaths were HIV related. In addition to age, factors independently associated with increased risk of death (relative risk, P value) were the following: AIDS (33.5, <.001); HIV infection (4.7, <.001); liver disease (2.4, <.001); and Medicare/Medicaid insurance (1.4,. 01). Those persons who had received care in an HTC had a significantly decreased risk of death (0.6,.002). Although HIV infection and the presence of severe liver disease remain strong predictors of mortality, survival is significantly greater among hemophilics who receive medical care in HTCs. (Blood. 2000;96:437-442)

Heparin neutralization is essential for accurate measurement of factor VIII activity and inhibitor assays in blood samples drawn from implanted venous access devices.

The purpose of this study was to determine the prevalence and effect of heparin contamination in samples drawn from implanted venous access devices (VADs, ports) on factor VIII activity and Bethesda inhibitor assay (BU) and the efficacy of heparinase to neutralize heparin. Plasma samples containing 85, 45, and 2 U/dL factor VIII were spiked in vitro with heparin from 0 to 3 U/mL. Factor VIII activity was assayed with a one-stage clotting assay on paired samples before and after heparinase, 25 mg/mL plasma. Paired patient samples drawn from VADs were assayed for heparin concentration, factor VIII, and BU before and after heparinase. At all three concentrations of factor VIII in vitro, the addition of heparin at 0.12 to 0.25 U/mL decreased assayed factor VIII activity. Heparinase neutralized up to 2 U/mL heparin and resulted in accurate factor VIII determination. Of 105 VAD samples, 47 (45%) had heparin contamination >0.05 U/mL. Of 47 heparin-contaminated samples, 42 showed decreased factor VIII activity in before/after comparisons. False-positive BU results were detected in 6 of 47 heparin-contaminated samples. Heparin contamination occurs frequently in samples drawn from VADs and could increase costs through excessive factor concentrate use. We recommend that all VAD samples be pretreated with heparinase before the assay of factor VIII activity or Bethesda inhibitor titers.

MRI findings in haemophilic joints treated with radiosynoviorthesis with development of an MRI scale of joint damage.

We hypothesized that magnetic resonance imaging (MRI) scans taken prior to radiosynoviorthesis may be predictive of response to the procedure in persons with haemophilia. Specifically, response would be inversely related to the severity of synovial hyperplasia. Radiosynoviorthesis was administered to 21 joints with recurrent haemorrhage (target joints). A detailed self-report of haemorrhage history, joint evaluation with scoring according to the World Federation of Haemophilia orthopaedic joint and pain scales, plain radiographs, and MRI studies of the joints were performed pre- and post-radiosynoviorthesis. To augment comparison of the MRI findings to those assessed using the Arnold-Hilgartner and Pettersson scales, a provisional MRI scale for evaluation of haemophilic arthropathy was designed. We found the MRI findings prior to the procedure were not predictive of clinical response; independent of the severity of synovial hyperplasia, most joints bled less and showed improvement by the WFH orthopaedic score. There was generally no change in the severity of synovial hyperplasia after the procedure. We conclude that MRI evaluation is not routinely indicated prior to radiosynoviorthesis.

The prothrombin Denver patient has two different prothrombin point mutations resulting in Glu-300-->Lys and Glu-309-->Lys substitutions.

Dysprothrombinaemia is a rare, congenital cause of bleeding. Fewer than 25 families who express a functional prothrombin (factor II) defect have been reported. The original patient with prothrombin Denver had a severe haemophilia-like bleeding disorder treated with weekly prophylactic factor replacement. Analysis of factor II activity and antigen in the patient showed a factor II activity of 5 units/dl and factor II antigen of 21 units/dl. Genomic DNA from the patient, mother and brother was obtained from peripheral blood white cells. Oligonucleotides were constructed, and prothrombin exons were amplified via polymerase chain reaction (PCR). The entire sequence of the thrombin portion of the molecule (exons VIII-XIV) and that of exons I-II and IV-VII was determined. This moderately severe dysprothrombinaemia was found to be associated with compound heterozygosity for two different Glu-->Lys point mutations, at amino acid positions 300 and 309. Assays of plasma from the prothrombin Denver proband suggested that the functional defect was in the activation of zymogen to enzyme.

Combined thrombolytic and anticoagulant therapy for venous thrombosis in children.

OBJECTIVES: To evaluate safety, efficacy, and outcome after combination thrombolytic and anticoagulant therapy. STUDY DESIGN: An open nonrandomized clinical protocol with prospective standardized monitoring and data collection. Children with a documented first episode of deep vein thrombosis were treated with urokinase 4400 U/kg load and per hour with unfractionated heparin at 10 U/kg/h. At 48 hours heparin infusions were increased to achieve a therapeutic level for 5 days. Children were given therapeutic warfarin for at least 3 months. Outcome was assessed at 48 hours and > or =1 year with history, physical examination, high-resolution imaging, and Doppler ultrasonography +/- impedance and photo plethysmography. RESULTS: Thirty-two children were treated. There was 1 thrombotic death, 1 nonfatal thrombus progression, and 1 pulmonary embolism. At 48 hours half of the children showed substantial clot lysis, and on follow-up these children had complete resolution and had no symptoms. Three children with poor early clot lysis had recurrent thromboemboli, pulmonary embolism, or both, 2 had limb pain and swelling, and 2 had asymptomatic swelling. Two children had minor bleeding, whereas systemic reactions were common. CONCLUSIONS: Combination therapy in children (urokinase and unfractionated heparin) was safe and efficacious. A prospective, randomized, controlled study in children is needed.