Consensus recommendations for use of central venous access devices in haemophilia

Non-viral and viral delivery systems for hemophilia A therapy: recent development and prospects

Recent advancements have focused on enhancing factor VIII half-life and refining its delivery methods, despite the well-established knowledge that factor VIII deficiency is the main clotting protein lacking in hemophilia. Consequently, both viral and non-viral delivery systems play a crucial role in enhancing the quality of life for hemophilia patients. The utilization of viral vectors and the manipulation of non-viral vectors through targeted delivery are significant advancements in the field of cellular and molecular therapies for hemophilia. These developments contribute to the progression of treatment strategies and hold great promise for improving the overall well-being of individuals with hemophilia. This review study comprehensively explores the application of viral and non-viral vectors in cellular (specifically T cell) and molecular therapy approaches, such as RNA, monoclonal antibody (mAb), and CRISPR therapeutics, with the aim of addressing the challenges in hemophilia treatment. By examining these innovative strategies, the study aims to shed light on potential solutions to enhance the efficacy and outcomes of hemophilia therapy.

Application of peripherally inserted central catheter in immune tolerance induction treatment of children with hemophilia A and accompanying inhibitors in China

OBJECTIVE

To explore the feasibility, safety and cost effectiveness of the use of peripherally inserted central catheter (PICC) in children with hemophilia A and inhibitors who underwent ITI treatment.

METHOD

This retrospective cohort study evaluated the effect of PICC placement and ITI on bleeding rates, costs, and parents' satisfaction before and within 6 months after PICC placement in children with hemophilia A and inhibitors.

RESULTS

A total of 20 children with hemophilia A and high-titer inhibitors were included, with a success rate for PICC placement of 100%, at a cost of ¥6730.50. Parents' satisfaction with PICC was 100%, and the total length of catheter indwelling was 6055 days. In terms of curative effect, the success rate of ITI treatment was 75%, and the annualized bleeding rate was decreased from 10.90 ± 12.16 times before placement to 2.10 ± 3.32 times (p < 0.05). The transportation expense for children and their parents to the clinic decreased from ¥20,920 ± 32,274.57 before catheter placement to ¥2915 ± 2195.99 (p < 0.05). Time of children missed school and their parents missed work decreased from 10.85 ± 22.36 days to 1.90 ± 3.58 (p < 0.05) days and 40.33 ± 46.11 days to 3.83 ± 7.11 days (p < 0.05), respectively.

CONCLUSION

The use of PICC for ITI treatment in children with hemophilia A and accompanying inhibitors in developing countries (e.g. China) can ensure the effect of ITI, reducing expense and improving the quality of life without obvious side effects.

Development and validation of knowledge, attitude and practice questionnaire for pediatric nurses to prevent central venous device-related thrombosis in hospitalized children

AIM

This study aimed to develop and validate a scientific and standardized knowledge, attitude and practice questionnaire of pediatric nurses' preventive care for central venous device-related thrombosis among hospitalized children.

BACKGROUND

Pediatric nurses play a significant role in the prevention of central venous device-related thrombosis for hospialized children. However, the status of pediatric nurses' knowledge, attitude and practice of central venous device-related thrombosis prevention has not been revealed due to the lack of assessment tools.

METHODS

This questionnaire was framed by the theory of knowledge, attitude and practice. The item pool was compiled through a literature review and a preliminary questionnaire was formed based on expert consultation. A total of 457 pediatric nurses from 10 tertiary class A general hospitals and specialized pediatric hospitals in China were selected for pre-survey. Item analysis, reliability and validity test were conducted to refine and evaluate the items to form a formal questionnaire.

RESULTS

A total of 54 items were proposed in three dimensions of knowledge, attitude and practice. In the exploratory factor analysis, five, three and three common factors were extracted for each dimension, accounting for 60.552%, 89.829% and 84.258% of the total variance, respectively. The content validity index of the three dimensions ranged from 0.968 to 1.000 at the scale level and from 0.833 to 1.000 at the item level. The Cronbach's α coefficients for the total questionnaire and each dimension were between 0.926 and 0.973. The retest reliability for the total questionnaire and each dimension was between 0.688 and 0.898.

CONCLUSION

The proposed questionnaire has good reliability and validity and it can be applied to evaluate pediatric nurses' knowledge, attitude and practice in preventing central venous device-related thrombosis for hospitalized children.

Central venous access devices implantation in children with severe hemophilia a: data from the children comprehensive care center of China

Objectives

To report the perioperative management experience of central venous access devices (CVAD) in Chinese children with severe hemophilia A (SHA) in China.

Methods

This retrospective study included SHA children who underwent Port-A-Cath or peripherally inserted central catheter (PICC) implantation between 2020/01 and 2021/07. Collected data included baseline characteristics, factor replacement regimen and CVAD-related complications.

Results

Nine patients had nine ports placed, and eight patients underwent 10 PICCs placement. Patients without or with low-titer inhibitor (<5 BU) received a port. The median preoperative and postoperative plasma-derived factor VIII (pd-FVIII) doses were 53.0 (44.4-61.1) and 315.9 (88.2-577.8) IU/kg. The median port duration was 189 (15-512) days, with infection incidence of 0.06 per 1000 CVAD days. Patients with high-titer inhibitors (>10 BU) received PICC. The median recombinant factor VIIa (rFVIIa) dose was 87.47 μg/kg before and for 5-7 doses after implantation over 2-3 days. The median PICC duration was 226.5 days, with infection incidence of 0.12 per 1000 catheter-days.

Conclusions

CVADs can be safely implanted in China. PICC implantation is a practical and safe option for SHA children with high-titer inhibitors.

Utility of Blood Cultures and Empiric Antibiotics in Febrile Pediatric Hemophilia Patients With Central Venous Access Devices

BACKGROUND

Children with hemophilia frequently require long-term central venous access devices (CVADs) for regular infusion of factor products. Hemophilia patients are not immunocompromised, but the presence and use of CVADs are associated with infections including bacteremia. Currently, the utility of blood cultures in evaluation of the febrile hemophilia patient with an indwelling CVAD is unknown, nor is optimal empiric antibiotic use.

METHODS

We performed a retrospective cross-sectional study of febrile immunocompetent hemophilia patients with CVADs presenting to a large academic urban pediatric emergency department from 1995 to 2017. We used a natural language processing electronic search, followed by manual chart review to construct the cohort. We analyzed rate of pathogen recovery from cultures of blood in subgroups of hemophilia patients, the pathogen profile, and the reported pathogen susceptibilities to ceftriaxone.

RESULTS

Natural language processing electronic search identified 181 visits for fever among hemophilia patients with indwelling CVADs of which 147 cases from 44 unique patients met study criteria. Cultures of blood were positive in 56 (38%) of 147 patients (95% confidence interval, 30%-47%). Seventeen different organisms were isolated (10 pathogens and 7 possible pathogens) with Staphylococcus aureus and coagulase-negative Staphylococcus species as the most common. Thirty-four percent of isolates were reported as susceptible to ceftriaxone. Positive blood cultures were more common in cases involving patients with inhibitors (n = 71) versus those without (n = 76), odds ratio, 7.4 (95% confidence interval, 3.5-15.9). This was observed irrespective of hemophilia type.

CONCLUSIONS

Febrile immunocompetent hemophilia patients with indwelling CVADs have high rates of bacteremia. Empiric antimicrobial therapy should be targeted to anticipated pathogens and take into consideration local susceptibility patterns for Staphylococcus aureus.

Estimating the risk of thrombotic events in people with congenital hemophilia A using US claims data

Aim: Compare thrombotic risk in people with congenital hemophilia A (PwcHA) to the general non-hemophilia A (HA) population. Patients & methods: US claims databases were analyzed to identify PwcHA. Incidence rates of myocardial infarction, pulmonary embolism, ischemic stroke, deep vein thrombosis and device-related thrombosis were compared with a matched cohort without HA. Results: Over 3490 PwcHA were identified and 16,380 individuals matched. PwcHA had a similar incidence of myocardial infarction and pulmonary embolism compared with the non-HA population, but a slightly higher incidence of ischemic stroke and deep vein thrombosis. The incidence of device-related thrombosis was significantly higher in PwcHA. Conclusion: This analysis suggests that PwcHA are not protected against thrombosis, and provides context to evaluate thrombotic risk of HA treatments.

Evidence-Based Strategies and Recommendations for Preservation of Central Venous Access in Children

Children with chronic illness often require prolonged or repeated venous access. They remain at high risk for venous catheter-related complications (high-risk patients), which largely derive from elective decisions during catheter insertion and continuing care. These complications result in progressive loss of the venous capital (patent and compliant venous pathways) necessary for delivery of life-preserving therapies. A nonstandardized, episodic, isolated approach to venous care in these high-need, high-cost patients is too often the norm, imposing a disproportionate burden on affected persons and escalating costs. This state-of-the-art review identifies known failure points in the current systems of venous care, details the elements of an individualized plan of care, and emphasizes a patient-centered, multidisciplinary, collaborative, and evidence-based approach to care in these vulnerable populations. These guidelines are intended to enable every practitioner in every practice to deliver better care and better outcomes to these patients through awareness of critical issues, anticipatory attention to meaningful components of care, and appropriate consultation or referral when necessary.

Optimizing bleed prevention throughout the lifespan: Womb to Tomb

The focus of care providers, patients and families is the ability to tailor care for persons with haemophilia (PWH) across the lifespan. Care requires knowledge of the bleeding disorder and age-related complications, risk of therapeutic interventions, and evaluation of individual characteristics that contribute to outcomes. The ultimate goal is to live a normal life without the burden of bleeding, for PWH and carriers. A wide range of therapeutic options is required to achieve personalized care. Over the last decade, substantial therapeutic advantages have been achieved in the treatment of haemophilia that include the development of a robust array of factor concentrates, novel haemostatic agents, and increased knowledge and awareness of disease associated outcomes and risk factors. Significant strides on the road to accessible gene therapy have been realized. This increased range of therapeutic modalities provides options for development and implementation of care plans for each patient at each stage of life that are more flexible compared to prior care regimens. Paradigms for management of haemophilia are changing. As a community, we must work together to use these resources wisely, to learn from outcomes with new therapies and diagnostic tools, to assure all patients can achieve improved care and outcomes regardless of disease state or country of origin.

Spanish Consensus Guidelines on prophylaxis with bypassing agents in patients with haemophilia and inhibitors

Prophylaxis with the blood clotting factor, factor VIII (FVIII) is ineffective for individuals with haemophilia A and high-titre inhibitors to FVIII. Prophylaxis with the FVIII bypassing agents activated prothrombin complex concentrates (aPCC; FEIBA® Baxalta) or recombinant activated factor VII (rFVIIa; Novo-Seven®, Novo Nordisk) may be an effective alternative. It was our aim to develop evidence -and expert opinion- based guidelines for prophylactic therapy for patients with high-titre inhibitors to FVIII. A panel of nine Spanish haematologists undertook a systematic review of the literature to develop consensusbased guidance. Particular consideration was given to prophylaxis in patients prior to undergoing immune tolerance induction (ITI) (a process of continued exposure to FVIII that can restore sensitivity for some patients), during the ITI period and for those not undergoing ITI or for whom ITI had failed. These guidelines offer guidance for clinicians in deciding which patients might benefit from prophylaxis with FVIII bypassing agents, the most appropriate agents in various clinical settings related to ITI, doses and dosing regimens and how best to monitor the efficacy of prophylaxis. The paper includes recommendations on when to interrupt or stop prophylaxis and special safety concerns during prophylaxis. These consensus guidelines offer the most comprehensive evaluation of the clinical evidence base to date and should be of considerable benefit to clinicians facing the challenge of managing patients with severe haemophilia A with high-titre FVIII inhibitors.

Evolution of the Treatments for Hemophilia

Although hemophilia has been recognized for centuries as an inherited disorder primarily affecting males, advances in treatments have been very recent. Initial availability of plasma-derived therapies offered significant improvements in morbidity and mortality, but the transmission of viruses quickly negated the benefit of early factor replacement products. After developing successful viral inactivation methods and subsequently developing recombinant technology, the manufacturing of factor concentrates became much safer. Access to safer factor products allowed for a shift from the treatment of bleeds to prevention, called prophylaxis. Although dosing and interval vary, prevention of joint disease is now a realistic goal. Unfortunately, despite advances in the safety of therapy, some patients are unable to use factor replacement products because they develop antibodies, known as inhibitors. Eradication of inhibitors is possible in the majority of patients, but it is expensive and takes time. Management of acute bleeding may require significantly higher doses of factor replacement or the use of a bypassing agent. As a result, patients with inhibitors are at increased risk for sequelae, including joint disease, life-threatening bleeding, infectious complications with central vascular access devices, and thrombotic complications.

Hemophilia Care in the Pediatric Age

Hemophilia is the most common of the severe bleeding disorders and if not properly managed since early infancy can lead to chronic disease and lifelong disabilities. However, it enjoys the most efficacious and safe treatment among the most prevalent monogenic disorders. Hemophilia should be considered in the neonatal period in the case of unusual bleeding or in the case of positive family history. Later, hemophilia should be suspected mainly in males because of abnormal bruising/bleeding or unusual bleeding following invasive procedures-for example, tonsillectomy or circumcision. Prophylactic treatment that is started early with clotting-factor concentrates has been shown to prevent hemophilic arthropathy and is, therefore, the gold standard of care for hemophilia A and B in most countries with adequate resources. Central venous access catheters and arterovenous fistulas play an important role in the management of hemophilia children requiring repeated and/or urgent administration of coagulation factor concentrates. During childhood and adolescence, personalized treatment strategies that suit the patient and his lifestyle are essential to ensure optimal outcomes. Physical activity is important and can contribute to better coordination, endurance, flexibility and strength. The present article focuses also on questions frequently posed to pediatric hematologists like vaccinations, day-care/school access and dental care.

Venous Thromboembolism in Children with Cancer and Blood Disorders

Venous thromboembolism (VTE) in children is multifactorial and most often related to a combination of inherited and acquired thrombophilias. Children with cancer and blood disorders are often at risk for VTE due to disease-related factors such as inflammation and abnormal blood flow and treatment-related factors such as central venous catheters and surgery. We will review risk factors for VTE in children with leukemia, lymphoma, and solid tumors. We will also review risk factors for VTE in children with blood disorders with specific focus on sickle cell anemia and hemophilia. We will present the available evidence and clinical guidelines for prevention and treatment of VTE in these populations.

Managing older patients with hemophilia

With access to safe factor products, the life expectancy of persons with hemophilia (PWHs) has increased almost 10-fold over the past 7 decades. Unfortunately, hand in hand with this success comes the burden of aging. As PWHs age, they are subject to develop many of the same risk factors as the general population, including increasing rates of hypertension, obesity, and diabetes. Such comorbidities predispose them to chronic diseases, such as cardiovascular disease and chronic kidney disease, although how their coagulopathy affects the expression of these conditions remains unclear. The older hemophilia population faces additional challenges, such as chronic joint arthropathy, which provokes falls and fractures, and complications related to HIV and hepatitis C infections, which greatly affect the incidence of cancer and liver disease. In light of the paucity of evidence-based guidelines to direct therapy, a new challenge has arisen for hematologists to optimally manage these complex age-related issues. In general, elderly PWHs should be treated similarly to their peers without hemophilia, with the addition of factor replacement therapy as appropriate. Primary prevention of risk factors should be emphasized, and close coordination between specialties is essential. This review will focus on common complications affecting the older hemophilia population, including cardiovascular disease, malignancy, liver disease, renal insufficiency, and joint disease.

Laboratory monitoring of new hemostatic agents for hemophilia

Prophylactic infusion of factor replacement products results in a reduction in long-term morbidity and mortality in patients with severe hemophilia. However, intravenous access is commonly through central venous access devices, which may result in complications such as infections and thrombosis. Available clinical data on extended half-life (EHL) factor replacement products indicate the potential for a significant reduction in the need for frequent infusions, eg, once per week for factor (F)IX and twice per week for FVIII. With the current generation of factor replacement products, individualized pharmacokinetics (pK) direct optimal prophylactic dosing. The available data on the EHL factor replacement products also confirm similar individualized variability. Optimal dosing of these therapies relies on accurate assays, of which there is a variety, although performance characteristics vary with the specific product being tested. Herein, the data on clinical trials and laboratory assays are reviewed.

Central venous access device (CVAD) complications in Haemophilia with inhibitors undergoing immune tolerance induction: Lessons from the international immune tolerance study

INTRODUCTION

Central venous access devices (CVADs) are frequently required as stable long-lasting venous access in children with haemophilia, especially those requiring immune tolerance induction (ITI) for inhibitors. CVAD infection is one of the most frequently reported catheter-related complications in this patient population.

AIM

Detailed review of CVAD complications from the International ITI (I-ITI) study and analysis of potential risk factors for such complications.

METHODS

Retrospective analysis of prospectively obtained data from the I-ITI study primarily focused on CVAD-related complications.

RESULTS

A total of 115 children were recruited and 183 CVADs were placed in 99 subjects resulting in 121,206 CVAD-days observed on-study. A total of 124 CVAD infections were reported in 41 of 99 (41%) subjects with an overall infection rate of 0.94 per 1000 CVAD-days (interquartile ranges 0-1.7). A similar number of infections were observed in the two treatment arms (median: 2 and 3 in high dose and low dose respectively). Infections occurred more frequently in the presence of external catheters than with fully implanted catheters (P = 0.026). Infected patients were significantly younger at the time of CVAD insertion (median age: 22 vs. 25 months, P = 0.020). Patients with Gram-positive infections were also significantly younger than those with Gram-negative infections (median age: 17 vs. 25 months, P < 0.0001).

CONCLUSION

CVAD infection was the most common complication observed in children with severe haemophilia and inhibitors in the frame of the I-ITI study. Younger age at CVAD insertion and external CVAD were associated with higher risk for infection. ITI outcome was unaffected by CVAD infections.

How I use bypassing therapy for prophylaxis in patients with hemophilia A and inhibitors

Inhibitor development poses a significant challenge in the management of hemophilia because once an inhibitor is present, bleeding episodes can no longer be treated with standard clotting factor replacement therapy. Consequently, patients with inhibitors are at increased risk for difficult-to-control bleeding and complications, particularly arthropathy and physical disability. Three clinical trials in patients with inhibitors have demonstrated that prophylaxis with a bypassing agent reduces joint and other types of bleeding and improves health-related quality of life compared with on-demand bypassing therapy. In hemophilia patients without inhibitors, the initiation of prophylaxis with factor (F) VIII or FIX prior to the onset of recurrent hemarthroses can prevent the development of joint disease. Whether this is also true for bypassing agent prophylaxis remains to be determined.

Considerations in individualizing prophylaxis in patients with haemophilia A

Prophylaxis is considered optimal care for children and adults with severe haemophilia A because of its proven ability to reduce joint and other bleeding episodes. However, a 'one size fits all' approach to prophylaxis is not ideal, potentially leading to over-treatment in some individuals and under-treatment in others. Moreover, a generic plan fails to take into account a patient's lifestyle and personal preferences. This article reviews the factors contributing to bleeding risk and joint damage and uses case studies to illustrate how these contributors can be weighed to individualize the prophylactic regimen, thereby increasing the likelihood of therapeutic success.

Central venous access devices in patients with hemophilia

Hemophilia is a hereditary disorder in which the major clinical manifestation is bleeding into the joints, muscles, internal organs and the CNS, often without any obvious trauma. Bleeding can be fatal as in the case of CNS hemorrhage, or severely debilitating following repeated bleeding into joints that results in crippling arthritis. Treatment for hemophilia includes the intravenous administration of clotting factor concentrates to replace the missing or defective protein. Venous access is therefore critical to the treatment of hemophilia and the prevention of complications due to bleeding. According to the US Centers for Disease Control and Prevention, approximately half of patients less than 16 years of age and one-third of all patients with hemophilia receive regular prophylactic injections of clotting factor concentrates. Prophylaxis, or the regular scheduled administration of antihemophilic factor concentrate, is effective in preventing bleeding. Among those patients with severe disease, in the absence of prophylaxis, approximately 13 bleeds, including nine joint hemorrhages, occur annually. In contrast, when prophylaxis is administered, the annual number of total and joint bleeds decreases to five and three, respectively. One of the major barriers to the more wide-spread use of prophylaxis is venous access. While peripheral venipuncture remains the first choice for venous access, central venous access devices are frequently used to facilitate repeated and/or urgent administration of clotting factor concentrates. The advantages of central venous access devices are well recognized in certain treatment regimens such as prophylaxis and immune tolerance therapy, as well as certain patient groups such as young children in whom venipuncture is often difficult and traumatic, and adults with scarred veins. Central venous access devices also allow earlier commencement of both home treatment and prophylaxis. The goal of this review is to discuss the different types of central venous access devices and their role in the management of hemophilia to provide practitioners that care for patients with hemophilia with the necessary information to make sound therapeutic recommendations to their patients.

Renal diseases in haemophilic patients: pathogenesis and clinical management

Haemophilia A and B are genetic X-linked bleeding disorders, caused by mutations in genes encoding factors VIII and IX, respectively. Clinical manifestations of haemophilia are spontaneous haemorrhage or acute bleeding caused by minor trauma, resulting in severe functional consequences that can culminate in a debilitating arthropathy. Life expectancy and quality of life of patients with haemophilia have dramatically improved over the last years, mainly for new therapeutic options and the awareness to the risk of HCV and HIV infections. Different clinical problems arise from this important change in history of patients with haemophilia. In particular, ageing-related diseases, such as diabetes, hypertension and cancer, and chronic viral infections are emerging as new challenges in this patient population. Among the different types of chronic illnesses, renal diseases are of special interest as they involve some difficult management issues. In fact, decisions regarding adequate preventive strategies and viral infection treatment, the choice of the dialytic modality, placement of vascular access and prescription of dialytic treatments are particularly complicated, because only few data are available. In this review, we discuss the pathogenesis of renal damage in patients with haemophilia, especially in those with blood-transmitted viral infections, and the major issues about the management of renal diseases, including problems related to dialytic treatment and kidney transplantation, providing practical algorithms to guide the clinical decision-making process.

Emergency department visits in children with hemophilia

BACKGROUND

The pediatric emergency department (ED) management of bleeding and other complications of hemophilia constitutes an increasingly important component of hemophilia therapy. This retrospective study examined the overall ED use by children with hemophilia in a single center, with a particular aim to investigate visits related to injury or bleeding, and those related to blood stream infection in patients with a central venous catheter (CVC).

METHODS

Electronic medical records of patients with hemophilia presenting to Children's Hospital of Michigan ED were reviewed. Different categories of ED visits over a 5-year period (January 2006-December 2010) were examined.

RESULTS

There were 536 ED visits from 84 male patients (median age 4 years, range 0-21) with hemophilia over the 5-year period. The reasons for ED visits were: injury or bleeding (61.2%); suspected CVC-related infection (11.8%); causes unrelated to hemophilia (19.2%); and routine clotting factor infusion (7.8%). Eighteen visits from six patients were secondary to injury or bleeding in a patient not yet diagnosed with hemophilia. An intracranial hemorrhage was detected in five visits. Overall, 5.4% of all visits represented distinct episodes of bloodstream infection.

CONCLUSION

The pediatric ED is an indispensable component of the overall hemophilia care, because: (1) patients with potentially lethal problems such as ICH or CVC-related infection may present to the ED for their initial management; (2) previously undiagnosed patients with hemophilia may also present to the ED for their first bleeding episodes, initiating the diagnostic investigations; (3) the ED provides after-hours treatment service for many episodes of injury or bleeding, and also for clotting factor infusion.

Future of coagulation factor replacement therapy

Over a million patients worldwide currently suffer from hemophilia and other congenital clotting factor deficiencies. Patients affected with hemophilia A and B are treated by intravenous replacement therapy of factor VIII and factor IX, respectively. Current hemophilia treatments have favorably supported their efficacy, tolerability, and safety profiles. The onset of alloantibodies inactivating the infused coagulation factor is the main problem in hemophilia patients rendering replacement therapies ineffective; another disadvantage is the short half-life of the infused clotting factors with the need for multiple and frequent infusions to manage a bleeding episode. Now, the challenge in the management of hemophilia treatment is the prolongation of the half-life and reduction in the immunogenicity of recombinant clotting factors. The bioengineering strategies, previously applied successfully to other therapeutic proteins, encourage the current efforts to produce novel coagulation factors with more prolonged bioavailability, with increased potency and resistance to inactivation and potentially reduced immunogenicity.

Preventing surgical site infection in haemophilia patients undergoing total knee arthroplasty

The rate of infection following primary total knee arthroplasty (TKA) in the general population is 1% on average. However, in persons with haemophilia (PWH), the mean rate of infection following primary TKA is nearly 8%.

QUESTIONS

why is the infection rate higher in persons with haemophilia compared with the general population? what should be done to correct this? A PubMed (MEDLINE) search and a Cochrane Library search were performed. The most important articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed the prevention of infection in PWH undergoing TKA. Patient-related risk factors predisposing to postoperative infection in the general population include immunodepression and previous infection in the knee. Methicillin-resistant Staphylococcus aureus (MRSA) is the most common organism in infected TKAs. Systematic preoperative screening by swab is very important. Prevention of MRSA-positive cases by means of nasal decontamination (mupirocin 3 days) is advisable. Preoperative antibiotic prophylaxis has shown itself to be an efficient method to lower infection rates. Operating theatres ideally should be equipped with laminar flow. In PWH, there are three additional risk factors: insufficient haemostasis, HIV-positive status, and central venous catheters (CVCs). Implementing the preventive measures for the general population and a sufficient level of clotting factor for 2-3 weeks can help diminish the infection in PWH undergoing TKA. In HIV-positive patients with CD4 count less than 200 cells/μl , early, vigorous treatment should be instituted for suspected infection and surgical intervention individualized based on the balance of risks and benefits. Strict adherence to handwashing and aseptic technique are essential elements of catheter care. Caregiver education is an integral part of CVC use and the procedural practices of users should be regularly reassessed. If TKA is contraindicated, arthroscopic knee joint debridement can relieve pain for several years and delay the need for TKA.

Long-lasting recombinant factor VIII proteins for hemophilia A

In the past 50 years, the lifespan of an individual affected with severe hemophilia A has increased from a mere 20 years to near that of the general unaffected population. These advances are the result of and parallel advances in the development and manufacture of replacement therapies. We are now poised to witness further technologic leaps with the development of longer-lasting replacement therapies, some of which are likely to be approved for market shortly. Prophylactic therapy is currently the standard of care for young children with severe hemophilia A, yet requires frequent infusion to achieve optimal results. Longer-lasting products will transform our ability to deliver prophylaxis, especially in very young children. Longer-lasting replacement therapies will require changes to our current treatment plans including those for acute bleeding, prophylaxis, surgical interventions, and even perhaps immunotolerance induction. Ongoing observation will be required to determine the full clinical impact of this new class of products.

Mortality, health care utilization and associated diagnoses in hospitalized patients with haemophilia in the United States: first reported nationwide estimates

To describe the in-hospital epidemiology of haemophilia A and B in the US we analysed the National Inpatient Sample (NIS), a stratified probability sample of 20% of all hospital discharges in the US for the year 2007. We applied sampling weights to represent all hospital discharges for haemophilia A and B identified using ICD-9 codes 286.0 and 286.1, respectively. Haemophilia (A or B) was one of all the listed diagnoses in 9737 discharges and principal diagnosis in 1684 discharges. The most common associated diagnoses in discharges with Haemophilia in adults and children were hypertension (28.1 ± 1.6%) and central line infections (15.2 ± 1.8%) respectively. No Hepatitis C or HIV was reported in children. Among 212 deaths, associated diagnoses included sepsis (37.9%), heart failure (30.2%), respiratory failure (28.3%), pneumonia (24.5%), HIV (14.2%), hepatic coma (5.2%) and intracranial haemorrhage (2.3%). All fifteen reported paediatric deaths occurred on day zero of life, the commonest associated diagnoses being Intraventricular haemorrhage and newborn haemorrhage-NOS (33% each). Median age of in-hospital mortality for diagnosis of Haemophilia was 68.3 years as compared to 72.3 years for all males for all hospitalizations in NIS combined. Mean hospital charges for haemophilia of $76823 ± 5530 were significantly higher than those from all causes of hospitalization of $26,120 ± 562. In-hospital mortality is rare in children with haemophilia beyond the neonatal period and age of mortality in adults is approaching that of the general male population. Hospitalization in children is most often due to central line infections and hospitalization and death in adults is primarily due to age-related illnesses.

The principal results of the International Immune Tolerance Study: a randomized dose comparison

The International Immune Tolerance Study was a multicenter, prospective, randomized comparison of high-dose (HD; 200 IU/kg/d) and low-dose (LD; 50 IU/kg 3 times/week) factor VIII regimens in 115 “good-risk,” severe high-titer inhibitor hemophilia A subjects. Sixty-six of 115 subjects reached the defined study end points: success, n = 46 (69.7%); partial response, n = 3 (4.5%); and failure, n = 17 (25.8%). Successes did not differ between treatment arms (24 of 58 LD vs 22/57 HD, P = .909). The times taken to achieve a negative titer (P = .027), a normal recovery (P = .002), and tolerance (P = .116, nonsignificant) were shorter with the HD immune tolerance induction (ITI). Peak historical (P = .026) and on-ITI (P = .002) titers were correlated inversely with success, but only peak titer on ITI predicted outcome in a multivariate analysis (P = .002). LD subjects bled more often (odds ratio, 2.2; P = .0019). The early bleed rate/month was 0.62 (LD) and 0.28 (HD; P = .000 24), decreasing by 90% once negative titers were achieved. Bleeding was absent in 8 of 58 LD versus 21 of 57 HD subjects (P = .0085). One hundred twenty-four central catheter infections were reported in 41 subjects (19 LD); infection frequency did not differ between the treatment arms. Neither bleeding nor infection influenced outcome. Although it was stopped early for futility and safety considerations, this trial contributed valuable data toward evidence-based ITI practice.

Plasma derivatives: new products and new approaches

The infusion of plasma-derived or recombinant factors to treat bleeding disorders such as hemophilia A and B is a success story in the management of a chronic disease. The effectiveness of this approach is however limited by challenges with adverse effects of treatment. The most notable of these are the development of inhibitory antibodies that target the protein therapeutic. The current standard of care for management of hemophiliacs is prophylactic treatment that includes frequent infusions of a Factor VIII product. Failure to comply with the prophylactic regimen is a major hurdle in the management of these patients. We discuss here more recent findings that argue for a pharmacogenetic approach to understanding (and eventually circumventing) immunogenicity. We also review strategies used to bioengineer coagulation factors to extend the half-lives of coagulation proteins. The rapid progress in the last few years to bioengineer coagulation factors in different ways to attain this goal is described. Finally, novel technologies and potential products are emerging that utilize synthetic molecules in lieu of replacement proteins obviating the limitations associated with replacement therapies.

Immune tolerance induction in haemophilia: evidence and the way forward

Given the inhibitor-associated morbidity resulting from limited effective treatment options, antibody eradication is the ultimate goal of inhibitor management. The only clinically proven strategy for achieving antigen-specific tolerance to factor VIII is immune tolerance induction (ITI). First reported over 30 years ago, much of our current knowledge about ITI in haemophilia A and B was derived from small cohort studies and retrospective national and international ITI registries. More recently, prospective randomised ITI trials have been designed and initiated to answer outstanding questions related to the optimisation of current therapeutic strategy in haemophilia A. However, due to the low incidence of inhibitor development in haemophilia B compared to haemophilia A, there are few comparable data from which to develop a useful evidence-based approach to the prevention and eradication of FIX inhibitors. The lack of an effective strategy is particularly problematic given the even greater morbidity associated with the almost unique occurrence of allergic and anaphylactic reactions that often herald FIX antibody development, and further complicates attempts to eradicate FIX inhibitors. Ultimately, successful inhibitor prevention and eradication strategies for both diseases will emerge from the clinical translation of our evolving knowledge of immune stimulation and tolerance. This paper will discuss our current understanding of immune tolerance outcome and outcome predictors for haemophilia A and B; it will also review the current consensus recommendations for ITI, as well as the emerging scientific body of immunological knowledge that may significantly impact the therapeutic and preventative strategies of the future.

Pharmacotherapy of haemophilia A

INTRODUCTION

Haemophilia A is due to factor VIII (FVIII) deficiency. The main treatment is replacement therapy with FVIII concentrates. However, these concentrates carried a high risk of blood-borne viral infections and still have a high risk of inducing anti-FVIII inhibitors.

AREAS COVERED

An overview of products available and therapeutic options for haemophilia A management in order to help in decision making. A literature search using Medline with the keywords: 'haemophilia', 'factor VIII', 'therapy', 'inhibitor', 'concentrate', 'bleeding', 'prophylaxis', 'on demand', 'plasma-derived', 'recombinant', 'coagulation factors', 'immunotolerance' was performed. The years 1960 - 2010 are included.

EXPERT OPINION

Progress in management of patients with haemophilia A has allowed increased life expectancy and quality of life. There is evidence that prophylaxis prevents or, at least, slows down arthropathy development when started early in childhood. FVIII concentrates have achieved high levels of blood-borne pathogen safety. However, treatment is frequently complicated by development of FVIII-neutralizing inhibitors, which prevent control of bleeding and predispose to a high morbidity and mortality risk. Bypassing agents are effective in bleeding treatment in a high percentage of cases. Prophylaxis with bypassing agents and their use in combination are offering opportunities in management of inhibitor patients. More evidence is necessary to understand how to prevent and manage this complication.

When should prophylaxis therapy in inhibitor patients be considered?

Currently, patients with severe haemophilia can expect to lead a relatively normal life including prevention of disabling arthropathy as a result of the development of factor replacement therapy and advances in the understanding of the use of such therapy given prophylactically. Unfortunately, a subset of patients develops neutralizing antibodies termed inhibitors rendering such therapy ineffective. These patients frequently develop recurrent joint bleeding resulting in arthropathy. Until recently, prophylactic therapy was not considered for patients with inhibitors because of the perceived lack of an effective therapeutic agent. However, an accumulation of case reports and a recent prospective study have suggested that prophylaxis with the currently available bypassing agents could be effective and appears to be safe in selected cases. This report will review the current data on prophylaxis with bypassing agents and suggest specific situations in which prophylaxis in inhibitor patients could be considered.