Optimization of the Alizarin Red S Assay by Enhancing Mineralization of Osteoblasts.

The alizarin red S assay is considered the gold standard for quantification of osteoblast mineralization and is thus widely used among scientists. However, there are several restrictions to this method, e.g., moderate sensitivity makes it difficult to uncover slight but significant effects of potentially clinically relevant substances. Therefore, an adaptation of the staining method is appropriate and might be obtained by increasing the mineralization ability of osteoblasts. In this study, cell culture experiments with human (SaOs-2) and murine (MC3T3-E1) osteoblasts were performed under the addition of increasing concentrations of calcium chloride (1, 2.5, 5, and 10 mM) or calcitonin (1, 2.5, 5, and 10 nM). After three or four weeks, the mineralization matrix was stained with alizarin red S and the concentration was quantified photometrically. Only calcium chloride was able to significantly increase mineralization, and therefore enhanced the sensitivity of the alizarin red S staining in a dose-dependent manner in both osteoblastic cell lines as well as independent of the cell culture well surface area. This cost- and time-efficient optimization enables a more sensitive analysis of potentially clinically relevant substances in future bone research.

Cardiac output and cerebral blood flow during carotid surgery in regional versus general anesthesia: A prospective randomized controlled study.

OBJECTIVE: Carotid endarterectomy (CEA) is a preventive procedure aimed at decreasing the subsequent risk of fatal or disabling stroke in patients with significant carotid stenosis. It is well-known that carotid surgery under ultrasound-guided regional anesthesia (US-RA) causes a significant increase in blood pressure, heart rate and stress hormone levels owing to increased sympathetic activity. However, little is known about the effects on cardiac output (CO), cardiac index (CI), and cerebral blood flow (CBF) under US-RA as compared with general anesthesia (GA). METHODS: Patients scheduled for CEA were randomized prospectively to receive US-RA (n = 37) or GA (n = 41). The primary end point was the change in CI after induction of anesthesia and the change from baseline over time at four different times during the entire procedure in the respective randomized US-RA and GA groups. In addition to systolic blood pressure and heart rate, we also recorded peak systolic velocity, end-diastolic velocity, and minimum diastolic velocity as seen from transcranial Doppler ultrasound examination, as well as regional cerebral oxygenation (rSO2) as seen from near-infrared refracted spectroscopy to evaluate cerebral blood flow. RESULTS: In the US-RA group, the CI increased after induction of anesthesia (3.7 ± 0.8 L/min/m2) and remained constant until the end of the procedure. In the GA group CI was significantly lower (2.4 ± 0.6 L/min/m2; P < .001). After induction of anesthesia, the rSO2 remained constant in the GA group on both the ipsilateral (63 ± 9 rSO2) and the contralateral (65 ± 7 rSO2) sides; in contrast, it significantly increased in the US-RA group (ipsilateral 72 ± 8 rSO2; P < .001; contralateral 72 ± 6 rSO2; P < .001). The transcranial Doppler ultrasound parameters (peak systolic velocity, end-diastolic velocity, and minimum diastolic velocity) did not differ between the US-RA and the GA group. The clinical outcome was similarly favorable for both groups. CONCLUSIONS: CI was maintained near baseline values throughout the procedure during US-RA, whereas a significant decrease in CI values was observed during CEA under GA. Near-infrared refracted spectroscopy values, reflecting blood flow in small vessels, were higher in US-RA patients than in those with GA. These differences did not influence clinical outcome.

Administration of fibrinogen concentrate combined with prothrombin complex maintains hemostasis in children undergoing congenital heart repair (a long-term propensity score-matched study).

BACKGROUND: Bleeding is a common problem in children with congenital heart disease undergoing major cardiac surgery requiring cardiopulmonary bypass (CPB). Little is known about optimal management with blood products. OBJECTIVE: To investigate clinical outcome and hemostatic effects of fibrinogen concentrate (FC) in combination with prothrombin complex concentrate (PCC) versus standard treatment with fresh frozen plasma (FFP) in children undergoing cardiac surgery. METHODS: For this single-institution cohort study, data on 525 children were analyzed. Propensity score matching in 210 children was applied to reduce the impact of various baseline characteristics. RESULTS: Three children treated with FC/PCC developed surgical site bleeding requiring surgical revision. One child developed central venous line-related thrombosis. Blood loss through chest tube drainage was independent of FC/PCC. Coagulation abnormalities were not present in any of these children. Time to extubation and ICU stay did not differ. In the FC/PCC group, children received (median, Q1, Q3) 52 mg/kg (32, 83) FC and 28IU/kg (13, 44) PCC. Fibrinogen concentration was comparable at baseline. On admission to the ICU, fibrinogen was higher in children receiving FC/PCC, namely, 232 mg/dL (196, 280), than in children receiving FFP (186 mg/dL, 149, 224; P < .001). On discharge from the ICU, values did not differ ((FC/PCC 416 mg/dL (288, 501)), non-FC/PCC 418 mg/dL (272, 585; P = 1.000)). CONCLUSION: FC/PCC was well tolerated and permitted hemostasis to be maintained, even in the very young. We were not able to detect a signal for inferiority of this treatment. We conclude that FC/PCC can safely replace FFP.

Shiga toxin 2a binds antithrombin and heparin, but does not directly activate platelets.

Escherichia coli-induced hemolytic uremic syndrome (eHUS) is a life-threatening complication of infection with Shiga toxin (Stx), in particular Stx2a-producing Escherichia coli. Enhanced coagulation activation with formation of microthrombi seems to be a key event in development of eHUS. Platelet activation has been postulated as a possible, but controversially debated mechanism. The present study investigated the effect of Stx2a on plasmatic coagulation and platelets. Binding studies were initially performed with ELISA and co-immunoprecipitation and supported by quartz crystal microbalance with dissipation monitoring (QCM-D). Antithrombin (AT) activity was measured using the automated BCS XP® system. ROTEM® was used for functional coagulation testing. Platelet binding and activation was studied with FACS and light-transmission aggregometry. We found binding of Stx2a to AT, an important inhibitor of blood coagulation, but only a mild albeit significant reduction of AT activity against FXa in the presence of Stx2a. QCM-D analysis also showed binding of Stx2a to heparin and an impaired binding of AT to Stx2a-bound heparin. ROTEM® using Stx2a-treated platelet-poor plasma revealed a significant, but only moderate shortening of clotting time. Neither binding nor activation of platelets by Stx2a could be demonstrated. In summary, data of this study suggest that Stx2a binds to AT, but does not induce major effects on plasmatic coagulation. In addition, no interaction with platelets occurred. The well-known non-beneficial administration of heparin in eHUS patients could be explained by the interaction of Stx2a with heparin.

Predicting Transfusion Requirements During Extracorporeal Membrane Oxygenation.

OBJECTIVE: Patients requiring extracorporeal membrane oxygenation (ECMO) have a well-known bleeding risk and the potential for experiencing possibly fatal thromboembolic complications. Risk factors and predictors of transfusion requirements during ECMO support remain uncertain. The authors hypothesized that compromised organ function immediately before ECMO support will influence transfusion requirements. DESIGN: A prospective observational study. SETTING: A tertiary, single-institutional university hospital. PARTICIPANTS: The study included 40 adult patients requiring ECMO for intractable cardiac and respiratory failure between July 2010 and December 2012. Blood samples were taken before initiation of ECMO (baseline), after 24 and 48 hours on ECMO, and 24 hours after termination of ECMO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Independent of veno-arterial or veno-venous support, 26% of patients required≥2 packed red blood cells per day (PRBC/d) and 74% of patients required<2 PRBC/d during ECMO. Requirements of≥2 PRBC/d during ECMO support were associated with higher creatinine levels and lower prothrombin times (PT, %) at baseline and with impaired platelet function after 24 hours on ECMO. Platelet function, activated by thrombin receptor-activating peptide stimulation, decreased by 30% to 40% over time on ECMO. Receiver operating characteristic curve analysis showed cut-off values for creatinine of 1.49 mg/dL (sensitivity 70%, specificity 70%; area under the curve [AUC] 0.76, 95% confidence interval [CI] 0.58-0.94), for PT of 48% (sensitivity 80%, specificity 59%; AUC 0.69, 95% CI 0.50-0.87), and for thrombin receptor-activating peptide (TRAP) 32 U (sensitivity 90%, specificity 68%; AUC 0.76, 95% CI 0.59-0.93). CONCLUSIONS: The results of this study demonstrated that increased creatinine levels and lower PT before ECMO and secondary impaired platelet function significantly increased transfusion requirement.

Point-of-care testing in critically ill patients.

Point-of-care (POC) testing in hemostasis has experienced a significant increase in the spectrum of available tests and the number of tests performed. Short turn-around time and observation of rapid changes in test results are facilitated. The quality control process in POC testing must encompass a preanalytic (collection), analytic (measurement), and postanalytic (clinical response) phase. Erroneous interpretation of findings and difficult quality controls can outweigh the advantages of POC testing.Only a limited number of hemostatic POC tests have proven useful so far: prothrombin time POC-monitoring of oral vitamin K antagonists; activated clotting time POC-monitoring of high-dose heparin therapy; platelet function analyzer (PFA; Siemens, Marburg, Germany) closure time (CT)-detection of von Willebrand disease and severe platelet function defects; whole blood aggregometry (WBA) Multiplate (Roche Diagnostics, Rotkreuz, Switzerland), and the VerifyNow system (Accumetrics, San Diego, CA)-detection of platelet dysfunction due to antiplatelet drugs; thromboelastography-continuous observation of clot formation and fibrinolysis. The use of various agonists in WBA and thromboelastography (TEG) requires some expertise. In experienced hands the PFA CT and WBA and TEG are recommended combinations.Application of POC testing depends strictly on whether it improves medical care and patient outcome. More POC test systems are in the research pipeline, but only a few will resist the ravages of time.

Extracorporeal membrane oxygenation induces short-term loss of high-molecular-weight von Willebrand factor multimers.

BACKGROUND: High-molecular-weight (HMW) von Willebrand factor (vWF) multimers are crucial for primary hemostasis. Increased shear stress from ventricular assist devices can provoke premature degradation of HMW vWF multimers. Whether similar loss of vWF multimers occurs during extracorporeal membrane oxygenation (ECMO) is not clear. METHODS: We conducted a prospective observational study in a clinical cohort of patients who required ECMO for intractable cardiac and/or respiratory failure. The primary end point was the quantity and quality of HMW vWF multimer bands before, during, and after ECMO support. To investigate further changes in primary hemostasis, we also measured vWF antigen activity (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), and factor VIII in 38 patients who required ECMO support before initiation of ECMO (baseline), after 24 and 48 hours on ECMO, and 24 hours after termination of ECMO therapy. RESULTS: Compared with baseline, vWF:Ag and vWF:RCo decreased after 24 hours of ECMO (mean ± SD, vWF:Ag, 307% ± 152% to 261% ± 138%, P = 0.002; vWF:RCo 282% ± 145% to 157% ± 103%, P < 0.0001) and remained lower during ongoing support (vWF:Ag 265% ± 128%, P = 0.025; vWF:RCo 163% ± 94%, P < 0.0001). After termination of ECMO, vWF:Ag was greater than baseline (359% ± 131%, P = 0.004) and vWF:RCo was similar to baseline levels (338% ± 142%, P = 0.046). Compared with baseline, the calculated vWF:RCo/vWF:Ag ratio decreased after 24 hours on support (0.96 ± 0.23 to 0.61 ± 0.17, P ≤ 0.0001) and remained lower during 48 hours on ECMO (0.63 ± 0.18, P ≤ 0.0001). After termination of ECMO support (0.94 ± 0.19, P = 0.437), values rapidly returned to baseline. The number of HMW vWF multimers (n) decreased from baseline after 24 hours on ECMO (21 ± 1.4 to 14 ± 1.8, P ≤ 0.0001) and after 48 hours on ECMO (15 ± 2.1, P ≤ 0.0001). Twenty-four hours after termination of ECMO support, HMW vWF multimeric pattern had returned to baseline values (21 ± 1.8, P = 0.551). CONCLUSIONS: Loss of HMW vWF multimer bands occurred in patients undergoing ECMO support and resolved after the termination of ECMO. Although not detectable with coagulation screening tests, a vWF:RCo/vWF:Ag ratio <0.7 during ECMO was highly indicative for loss of HMW vWF multimers. Our findings may at least in part explain increased bleeding tendency during ECMO therapy. Administration of vWF concentrates may support restoration of primary hemostasis in patients with relevant bleeding during ECMO support.

Fibrinogen concentrate in dilutional coagulopathy: a dose study in pigs.

Dilutional coagulopathy can be reversed with fibrinogen concentrate. Effects of different fibrinogen dosages on clot function are not defined; high doses may increase the risk of thromboemboembolism. This study investigated the effect of six fibrinogen dosages on coagulation profile and blood loss in coagulopathic pigs. Forty-two pigs underwent a 60% hemodilution (HD) with hydroxyethylstarch (HES 130/0.4). After a standardized bone injury, animals randomly received 37.5, 75, 150, 300, 450 or 600 mg/kg fibrinogen (FGTW, LFB) or 500 ml of saline. Four hours later, a standardized liver injury was performed. Animals were then observed for two hours or until death. Blood loss was measured after death; Hemodynamic and coagulation parameters (thromboelastometry) were measured at baseline (BL), after HD, 15', 1, 2, 4 hours after fibrinogen administration and 2 hours after liver injury or right before the animals' death. Occurrence of thrombosis was examined in histological slides of internal organs. Statistical significance was set at p < 0.05. Doses of 150 mg/kg fibrinogen and higher reversed dilutional coagulopathy: Maximum clot firmness (MCF) was decreased after hemodilution (36 ± 3 mm vs. 65 ± 4 mm at BL, p < 0.05) and returned to BL after fibrinogen administration (69 ± 5 mm). Blood loss was significantly decreased with increased fibrinogen dosages: 42 ± 19 (sham), 34 ± 14 (75 mg/kg), 29 ± 13 (150 mg/kg), 28 ± 10 ml/kgbw (600 mg/kg). Fibrinogen (150-600 mg/kg) normalized clot firmness and decreased blood loss. No signs of hypercoagulability or thromboembolism were detected after high dosages.

Biopsychronology: live confocal imaging of biopsies to assess organ function.

Prolonged ischemia (I) times caused by organ procurement and transport are main contributors to a decrease in organ function, which is further enhanced during reperfusion (R). This combined damage, referred to as ischemia-reperfusion injury (IRI), is a main contributor to delayed graft function, which leads to costly and lengthy follow-up treatments or even organ loss. Methods to monitor the status of a graft prior to transplantation are therefore highly desirable to optimize the clinical outcome. Here, we propose the use of fine needle biopsies, which are analyzed by real-time live confocal microscopy. Such a combination provides information about the functional and structural integrity of an organ within a few minutes. To confirm the feasibility of this approach, we obtained fine needle biopsies from rodent kidneys and exposed them to various stress conditions. Following the addition of a range of live stains, biopsies were monitored for mitochondrial function, cell viability, and tissue integrity using confocal live cell imaging. Our data demonstrate that this procedure requires minimal time for sample preparation and data acquisition and is well suitable to record organ damage resulting from unphysiological stress.

Update on the Use of Thrombopoietin-Receptor Agonists in Pediatrics.

This review summarizes the rationale and current data on the use of thrombopoietin receptor agonists (TPO-RAs) for treating severe thrombocytopenia in infants, children, and adolescents. It focuses on substances that have been approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) for pediatric patients. Romiplostim and eltrombopag are already established as second-line treatment for persistent or chronic immune thrombocytopenia (ITP). As in adults, TPO-RAs are currently also evaluated in severe aplastic anemia (SAA), chemotherapy-induced thrombocytopenia (CIT), myelodysplastic syndromes (MDS), and poor engraftment after hematopoietic stem cell transplantation in pediatric and adolescent patients. Moreover, studies on the implication of TPO-RA in treating rare inherited thrombocytopenias, such as Wiskott-Aldrich syndrome (WAS), congenital amegakaryocytic thrombocytopenia (CAMT), or MYH9-associated thrombocytopenia, deserve future attention. Current developments include testing of avatrombopag and lusutrombopag that are approved for the treatment of thrombocytopenia associated with chronic liver disease (CLD) in adult patients. In pediatric and adolescent medicine, we expect in the near future a broader use of TPO-RAs as first-line treatment in primary ITP, thereby considering immunomodulatory effects that increase the rate of sustained remission off-treatment, and a selective use in rare inherited thrombocytopenias based on current clinical trials.

Long-Term Comparison of Two- and Three-Dimensional Computed Tomography Analyses of Cranial Bone Defects in Severe Parietal Thinning.

Parietal thinning was detected in a 72-year-old with recurrent headaches. Quantification of bone loss was performed applying two- and three-dimensional methods using computerized tomographies. Two-dimensional methods provided accurate measurements using single-line analyses of bone thicknesses (2.13 to 1.65 and 1.86 mm on the left and 4.44 to 3.08 and 4.20 mm on the right side), single-point analyses of bone intensities (693 to 375 and 403 on the left and 513 to 393 and 411 Houndsfield Units on the right side) and particle-size analyses of low density areas (16 to 22 and 12 on the left and 18 to 23 and 14 on the right side). Deteriorations between days 0 and 220 followed by bone stability on day 275 were paralleled using the changed volumes of bone defects to 1200 and finally 1133 mm3 on the left side and to 331 and finally 331 mm3 on the right side. Interfolding as measurement of the bones' shape provided changes to -1.23 and -1.72 mm on the left and to -1.42 and -1.30 mm on the right side. These techniques suggest a stabilizing effect of corticosteroids between days 220 and 275. Reconstruction of computerized tomographies appears justified to allow for quantification of bone loss during long-term follow-up.

[Treatment of haemophilia in Austria]. / Hämophilie-Behandlung in Österreich.

This guideline is intended to provide practical guidance for the diagnosis and treatment of haemophilia in Austria. Few randomized controlled interventional trials are available addressing the treatment of haemophilia, therefore recommendations are usually based on low level of evidence and represent expert consensus.This guideline is based on the WFH guideline, published in 2020, and adapted according to the national circumstances and experience.It includes recommendations and suggestions for diagnosis and follow-up visits and pharmacological therapies for treatment and prophylaxis. Further topics comprise special aspects in children and adults with severe haemophilia, outcome measurement, and management of trauma, special bleedings and interventions, including dental procedures, inhibitors, management of haemophilia carriers, and psychosocial aspects.

Patent ductus arteriosus, low platelets, cyclooxygenase inhibitors, and intraventricular hemorrhage in very low birth weight preterm infants.

OBJECTIVE: To assess the risk for intraventricular hemorrhage (IVH) in very low birth weight preterm infants with patent ductus arteriosus (PDA) and low platelet count with treatment with cyclooxygenase (COX) inhibitors. STUDY DESIGN: Diagnosis and treatment of PDA, as well as risk factors for IVH, were assessed using prospectively collected data of all infants born at a gestational age <32 weeks and with a birth weight ≤ 1500 g at Innsbruck University Hospital (January 2003-December 2009). Infants with severe thrombocytopenia (<50 × 10(9)/L) were excluded from analysis. RESULTS: Sixty-five (20%) of the 325 infants had IVH, and 149 (45.9%) of the 325 were treated with COX inhibitors. Treatment of PDA with COX inhibitors was not an independent risk predictor for IVH in preterm infants with platelets ≥ 100 × 10(9)/L. However, COX inhibitors amplified the risk of bleeding in the presence of moderately decreased platelets (50-99 × 10(9)/L) on days of life 2-7. Multivariable OR for IVH were 0.89 [95% CI 0.43-1.87] for patients with platelets ≥ 100 × 10(9)/L and treatment with COX inhibitors, 3.40 [95% CI 1.13-10.29] for those with moderately decreased platelets without treatment, and 53.3 [95% CI 5.9-484] for patients with both moderately decreased platelets and COX inhibitor treatment compared with those with platelets ≥ 100 × 10(9)/L and no treatment (reference group) (P < .001). CONCLUSION: In very low birth weight infants with moderate thrombocytopenia treatment with COX inhibitors increased the risk for intracerebral bleeding. Any benefits of this therapy should be carefully balanced against this potential hazard.

Progress in Hemostasis (Part 1): Improved Management of Inherited Platelet Disorders: Reality or Illusion?

Platelets are key drivers of hemostasis. Low platelet counts, dysfunction in platelet adhesion, and aggregation lead to increased bleeding tendency. Inherited platelet disorders (IPDs) form a highly heterogeneous group of rare diseases with variable bleeding tendency. IPDs may be associated with other signs and symptoms often referred to as "syndromic." The underlying genetic defect may prone patients to develop hematopoietic diseases such as leukemia. Over the last decade, accumulating knowledge in genetics has led to the detection of many "new" platelet disorders. However, still many patients with a well-described platelet dysfunction remain undetected until severe bleeding occurs.

Treatment of Inherited Platelet Disorders: Current Status and Future Options.

Inherited platelet disorders (IPDs) comprise a heterogeneous group of entities that manifest with variable bleeding tendencies. For successful treatment, the underlying platelet disorder, bleeding severity and location, age, and sex must be considered in the broader clinical context. Previous information from the AWMF S2K guideline #086-004 (www.awmf.org) is evaluated for validity and supplemented by information of new available and future treatment options and clinical scenarios that need specific measures. Special attention is given to the treatment of menorrhagia and risk management during pregnancy in women with IPDs. Established treatment options of IPDs include local hemostatic treatment, tranexamic acid, desmopressin, platelet concentrates, and recombinant activated factor VII. Hematopoietic stem cell therapy is a curative approach for selected patients. We also provide an outlook on promising new therapies. These include autologous hematopoietic stem cell gene therapy, artificial platelets and nanoparticles, and various other procoagulant treatments that are currently tested in clinical trials in the context of hemophilia.

Clinical Trials in Chronic Arthritic Diseases with Underestimated Impact of Placebo Effects on Study Size Calculation.

Whether and to which extent placebo treatment in double-blinded randomized controlled clinical trials is effective in chronic arthritic diseases has not been studied before. Therefore, a systematic literature search was undertaken to detect eligible trials. Demographic data of the placebo groups as well as concomitant and previous disease outcomes were collected. Analyses of significant bivariate correlations and linear regression between clinical endpoints and characteristics of the placebo groups were performed. A total of 152 double-blinded randomized controlled studies, including 21,616 participants in the placebo groups, was analyzed. The results of bivariate correlations and linear regressions revealed significant positive associations between responses in the placebo groups and the following factors: (i) naïvety of previous treatment and (ii) early stage of disease. In addition to the clinical relevance, the results support the importance of the placebo effect on study size calculations, and will allow an optimized calculation of patients' numbers for early placebo-controlled trials conducted in patients with chronic arthritic diseases.

State-of-the-Art Targeted High-Throughput Sequencing for Detecting Inherited Platelet Disorders.

Inherited platelet disorders (IPDs) are a heterogeneous group of rare entities caused by molecular divergence in genes relevant for platelet formation and function. A rational diagnostic approach is necessary to counsel and treat patients with IPDs. With the introduction of high-throughput sequencing at the beginning of this millennium, a more accurate diagnosis of IPDs has become available. We discuss advantages and limitations of genetic testing, technical issues, and ethical aspects. Additionally, we provide information on the clinical significance of different classes of variants and how they are correctly reported.

Loss or Dilution-A New Diagnostic Method to Assess the Impact of Dilution on Standard Laboratory Parameters.

Intraoperative fluid therapy is regularly used in patients undergoing cardiac surgery procedures with cardiopulmonary bypass (CPB). Although fluid administration has several advantages, it unavoidably leads to hemodilution. The hemodilution may further influence the interpretation of concentration-based laboratory parameters like hemoglobin (Hgb), platelet count (PLT) or prothrombin time (PT). These all parameters are commonly used to guide blood product substitution. To assess the impact of dilution on these values, we performed a prospective observational study in 174 patients undergoing elective cardiac surgery. We calculated the total blood volume according to Nadler's formula, and fluid therapy was correlated with a newly developed dilution coefficient formula at the end of CPB. Intravenously applied fluids were measured from the beginning of the anesthesia (baseline, T0) and 15 min after the end of protamine infusion (end of CPB, T1). The amount of the administered volume (crystalloids or colloids) was calculated according to the percentage of the intravascular fluid effect, and intraoperative diuresis was further subtracted. The median blood volume increased by 148% in all patients at T1 compared to the calculated total blood volume at T0. This led to a dilution-dependent decrease of 38% in all three parameters (Hgb 24%, corrCoeff = 0.53; PLT 41%, corrCoeff = 0.68; PT 44%, corrCoeff = 0.54). The dilution-correlated decrease was significant for all parameters (p < 0.001), and the effect was independent from the duration of CPB. We conclude that the presented calculation-based approach could provide important information regarding actual laboratory parameters and may help in the guidance of the blood product substitution and potential transfusion thresholds. Further research on the impact of dilution and related decision-making for blood product substitution, including its impact on morbidity and mortality, is warranted.

Low Bone Mineral Density in Hemophiliacs.

OBJECTIVE: To review the current knowledge on bone health in patients with hemophilia A and the underlying pathogenetic mechanisms. DATA SOURCES: Original research articles, meta-analyses, and scientific reviews. DATA SYNTHESIS: Already in childhood, patients with hemophilia A are prone to low bone mineral density, leading to osteopenia and/or osteoporosis. Initially associated with the life style of hemophilia, today we are faced with accumulating evidence that coagulation factor VIII is involved directly or indirectly in bone physiology. CONCLUSION: Understanding the role of factor VIII and the mechanisms of decreased bone mineral density in hemophilia A is critically important, especially as non-factor replacement therapies are available, and treatment decisions potentially impact bone health.

Direct thrombin and factor Xa inhibitors in children: a quest for new anticoagulants for children.

Venous thrombosis and pulmonary embolism rarely occur in children but are associated with significant morbidity and mortality. Venous thromboembolism (VTE) mostly affects children with severe underlying conditions and multiple risk factors. Newborns and adolescents are at the highest risk. Standard and low molecular weight heparins and vitamin K antagonists are routinely used for the prevention and treatment of VTE. The new anticoagulants, both parenteral such as argatroban, bivalirudin and fondaparinux and oral such as dabigatran and rivaroxaban, have favourable pharmacological properties, all are approved for clinical use in adults and are currently being investigated in children. Argatroban is the only new anticoagulant licensed for use in children so far. The role of these new anticoagulants as alternative anticoagulants for children remains to be defined. This review focuses on the characteristics of VTE in children and reviews current knowledge on the use of the new thrombin and factor Xa inhibitors in this population.