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Abstract: Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after evaluation of plasma coagulation and platelet function. Patients with BDUC (n = 375) recorded in the Vienna Bleeding Biobank were analyzed in comparison with healthy controls (HCs; n = 100) in this case-control study. Plasmin generation (PG) parameters were analyzed using calibrated fluorescence detection in citrated plasma. Turbidimetric plasma clot formation/lysis of 293 (78%) patients with BDUC and confocal microscopy of clots from representative patients with BDUC (n = 6) and HCs (n = 9) were assessed. In the PG analysis, patients with BDUC exhibited lower velocity and peak plasmin levels but a higher endogenous plasmin potential than HCs. Peak plasmin levels correlated with maximum clot absorbance but not with clot lysis time. Clot absorbance is an indicator of clot fiber density. Confocal microscopy analysis revealed a tendency towards thicker fibers in clots of patients with BDUC, which negatively correlated with peak plasmin (r = -0.561; P = .030). Peak plasmin correlated weakly with factor XIII, but not with other fibrinolytic factors (alpha2-antiplasmin, thrombin activatable fibrinolysis inhibitor, or plasminogen activator inhibitor 1) or bleeding severity. A model comprising fibrinogen and parameters of PG yielded high predictive power in discriminating between patients with BDUC and HCs across a fivefold stratified cross validation (80% of data; mean area under the curve [AUC], 0.847). The model generalized well to unseen data (20% of data; AUC, 0.856). Overall, patients with BDUC counterintuitively exhibited reduced peak plasmin levels, potentially related to altered clot structure., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Background: Bleeding disorder of unknown cause (BDUC) is characterized by a bleeding phenotype in the setting of normal hemostatic testing. No standardized diagnostic criteria or treatment algorithms exist for people with BDUC. To address the unmet need, the International Society on Thrombosis and Haemostasis von Willebrand Factor Scientific Subcommittee performed a real-world survey aimed at addressing knowledge gaps, developing consensus pathways, and ultimately improving care., Objectives: We sought to determine current international clinical practices in the investigation, registration, and treatment of people with BDUC internationally., Methods: An online structured survey was conducted of healthcare providers who managed patients with bleeding disorders using the ISTH RedCap tool., Results: Two hundred sixteen respondents from 39 countries were included in the final analysis. The clinical assessment of those with a possible bleeding disorder varied, with only 55% excluding hypermobility but high levels (80%) of bleeding assessment tool usage. In hemostatic testing, only the prothrombin time and activated partial thromboplastin time tests gained universal support. Tranexamic acid was favored for prophylaxis for minor (71%)/major (59%) surgeries and pregnancy (58%), but advice on the treatment if bleeding occurred was heterogeneous. The management of heavy menstrual bleeding in women despite combined oral contraceptive pill use also proved challenging, with healthcare providers selecting multiple alternative strategies., Conclusion: Significant variation exists in the recognition, registration, and management of people with BDUC worldwide. This survey emphasizes the need for consensus pathways to diagnose and treat BDUC to standardize and improve care for patients internationally., Competing Interests: Declaration of competing interests C.K. has no conflicts to declare. W.T. has served on advisory boards for Grifols, Sanofi, Daiichi Sankyo, Ablynx, Takeda, LFB Biopharmaceuticals, and CSL Behring and received speaker’s fees from Takeda, Bayer, Pfizer, Sobi, Novo Nordisk, AstraZeneca, Alexion, and Portola as well as educational support from CSL Behring, Octapharma, and CSL Behring. M.L. has served on an advisory board for CSL Behring as a consultant for Sobi, CSL Behring, and Band Therapeutics and received speaker fees from Sobi and Takeda. R.I.B.’s institution received grants for clinical research from Bayer, Takeda, Pfizer, Daiichi Sankyo, CSL Behring, Roche, Amgen, Celgene, Rigel Pharmaceuticals, Ionis Pharmaceuticals, AbbVie, Sanofi, MorphoSys AG, Acerta Pharma, Jansen-Cileg, Bristol Myer Squibb, Boehringer Ingelheim, and Astra Zeneca. The institution is in receipt of equipment and reagents for research from Werfen and Technoclone. He received honoraria for speaking at educational meetings from Bayer, Bristol Myers Squibb, Cardinal Health, and Astra Zeneca. He provided expert testimony for Sandoz. He has participated on a Data Safety Monitoring Board or Advisory Boards for Roche, Janssen-Celeg, CSL Behring, Astra Zeneca, and George Institute. J.S.O’D. has served on the speaker’s bureau for Baxter, Bayer, Novo Nordisk, Boehringer Ingelheim, Leo Pharma, Takeda, and Octapharma. He has also served on the advisory boards of Baxter, Bayer, Octapharma CSL Behring, Daiichi Sankyo, Boehringer Ingelheim, Takeda, and Pfizer. J.S.O’D. has served on the speaker’s bureau for Baxter, Bayer, Novo Nordisk, Boehringer Ingelheim, Leo Pharma, Takeda, and Octapharma; has also served on the advisory boards of Baxter, Bayer, Octapharma CSL Behring, Daiichi Sankyo, Boehringer Ingelheim, Takeda, and Pfizer; and has received research grant funding awards from Baxter, Bayer, Pfizer, Shire (now part of Takeda), Takeda, and Novo Nordisk. A.S.L. has no conflicts of interest to declare., (Copyright © 2024. Published by Elsevier Inc.)

Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after exhaustive evaluation of plasmatic coagulation and platelet function. This review explores the utility of global hemostatic assays as confirmatory tests and in elucidating the pathophysiology of BDUC. Unlike traditional hemostatic tests that focus on coagulation factors, global assays are conducted both in plasma and also whole blood. These assays provide a more comprehensive understanding of the cell-based model of coagulation, aid in the identification of plasmatic factor abnormalities that may reduce hemostatic capacity, and allow for the assessment of impaired platelet-endothelial interactions under shear stress, as well as hyperfibrinolytic states. While clinical tests such as skin bleeding time and global assays such as PFA-100 exhibit limited diagnostic capacity, the role of viscoelastic testing in identifying hemostatic dysfunction in patients with BDUC remains unclear. Thrombin generation assays have shown variable results in BDUC patients; some studies demonstrate differences compared with healthy controls or reference values, whereas others question its clinical utility. Fibrinolysis assessment in vitro remains challenging, with studies employing euglobulin clot lysis time, plasma clot lysis time, and fluorogenic plasmin generation yielding inconclusive or conflicting results. Notably, recent studies suggest that microfluidic analysis unveils shear-dependent platelet function defects in BDUC patients, undetected by conventional platelet function assays. Overall, global assays might be helpful for exploring underlying hemostatic impairments, when conventional hemostatic laboratory tests yield no results. However, due to limited data and/or discrepant results, further research is needed to evaluate the utility of global assays as screening tools., Competing Interests: D.M. received honoraria for advisory board meetings and lectures from CSL Behring., A.A. declares no conflict of interest. J.G. received honoraria for lectures and advisory board meetings, and research funding for the Medical University of Vienna from CSL Behring, Novartis, Amgen, Sobi, and Takeda., (Thieme. All rights reserved.)

Patients with an unexplained mild to moderate bleeding tendency are diagnosed with bleeding disorder of unknown cause (BDUC), a classification reached after ruling out other mild to moderate bleeding disorders (MBD) including von Willebrand disease (VWD), platelet function defects (PFDs), coagulation factor deficiencies (CFDs), and non-hemostatic causes for bleeding. This review outlines our diagnostic approach to BDUC, a diagnosis of exclusion, drawing on current guidelines and insights from the Vienna Bleeding Biobank (VIBB). According to guidelines, we diagnose VWD based on VWF antigen and/or activity levels ≤50 IU/dL, with repeated VWF testing if VWF levels are <80 IU/dL. This has been introduced in our clinical routine after our findings of diagnostically relevant fluctuations of VWF levels in a high proportion of MBD patients. PFDs are identified through repeated abnormalities in light transmission aggregometry (LTA), flow cytometric mepacrine fluorescence, and glycoprotein expression analysis. Nevertheless, we experience diagnostic challenges with regard to reproducibility and unspecific alterations of LTA. For factor (F) VIII and FIX deficiency, a cutoff of 50% is utilized to ensure detection of mild hemophilia A or B. We apply established cutoffs for other rare CFD being aware that these do not clearly reflect the causal role of the bleeding tendency. Investigations into very rare bleeding disorders due to hyperfibrinolysis or increase in natural anticoagulants are limited to cases with a notable family history or distinct bleeding phenotypes considering cost-effectiveness. While the pathogenesis of BDUC remains unknown, further explorations of this intriguing area may reveal new mechanisms and therapeutic targets., Competing Interests: D.M. received honoraria for advisory board meetings and lectures from CSL Behring, a research grant from CSL Behring (Prof. Heimburger award) and travel support by Sobi, Novo Nordisk, Pfizer, and Roche.J.G. received research grants from CSL Behring, Sobi, Takeda, Amgen, and Novartis for the Medical University of Vienna; honoraria for lectures and advisory board meetings from CSL Behring, Sobi, Novartis, and Amgen.I.P. received a grant from CSL Behring for the Medical University of Vienna; honoraria from CSL Behring, Sobi, Takeda, Pfizer, for lectures and advisory board meetings; as well as travel support by Sobi., (Thieme. All rights reserved.)

In many patients referred with significant bleeding phenotype, laboratory testing fails to define any hemostatic abnormalities. Clinical practice with respect to diagnosis and management of this patient cohort poses significant clinical challenges. We recommend that bleeding history in these patients should be objectively assessed using the International Society on Thrombosis and Haemostasis (ISTH) bleeding assessment tool. Patients with increased bleeding assessment tool scores should progress to hemostasis laboratory testing. To diagnose bleeding disorder of unknown cause (BDUC), normal complete blood count, prothrombin time, activated partial thromboplastin time, thrombin time, von Willebrand factor antigen, von Willebrand factor function, coagulation factors VIII, IX, and XI, and platelet light transmission aggregometry should be the minimum laboratory assessment. In some laboratories, additional specialized hemostasis testing may be performed to identify other rare causes of bleeding. We recommend that patients with a significant bleeding phenotype but normal laboratory investigations should be registered with a diagnosis of BDUC in preference to other terminology. Global hemostatic tests and markers of fibrinolysis demonstrate variable abnormalities, and their clinical significance remains uncertain. Targeted genomic sequencing examining candidate hemostatic genes has a low diagnostic yield. Underlying BDUC should be considered in patients with heavy menstrual bleeding since delays in diagnosis often extend to many years and negatively impact quality of life. Treatment options for BDUC patients include tranexamic acid, desmopressin, and platelet transfusions., Competing Interests: Declaration of competing interests No funding was sought for design, data interpretation, or manuscript writing. Individual conflict of interest declaration is listed below. R.I.B.’s institution received grants for research clinical research from Bayer, Takeda, Pfizer, Daiichi Sankyo, CSL Behring, Roche, Amgen, Celgene, Rigel Pharmaceuticals, Ionis Pharmaceuticals, AbbVie, Sanofi, MorphoSys AG, Acerta Pharma, Jansen-Cileg, Bristol-Myers Squibb, Boehringer Ingelheim, and Astra Zeneca. The institution is in receipt of equipment and reagents for research from Werfen and Technoclone. He received honoraria for speaking at educational meetings from Bayer, Bristol Myers Squibb, Cardinal Health, and Astra Zeneca. He provided expert testimony for Sandoz. He has participated on a Data Safety Monitoring Board or Advisory Boards for Roche, Janssen-Celeg, CSL Behring, Astra Zeneca, and George Institute. A.M. has received consultancy fees from Pfizer and CSL Behring and speaker fees from Astra Zeneca. W.T.: speakers fees from Bayer, Pfizer, AstraZeneca, Takeda, Novo Nordisk, CSL Behring, Alexion, Portola, Sanofi, and Sobi. Advisory boards for Pfizer, AstraZeneca, Sanofi, Ablynx, Takeda, Novo Nordisk, Grifols, LFB Biopharmaceuticals, and Daiichi Sankyo. Support to attend educational meetings from CSL Behring and Bayer. M.L. has served on advisory boards for CSL Behring, as a consultant for Sobi, CSL Behring, Takeda, and Band Therapeutics, received speaker fees from Sobi and Takeda, and has research funding from Takeda. R.S.: consultancy fees from Band/Guardian Therapeutics, Star/Vega Therapeutics, Roche, BioMarin Pharmaceuticals, Genentech, LFB, Bayer, Novo Nordisk. Octapharma AG, and Takeda. Her institution received investigator-initiated research grants from Takeda, Octapharma, LFB, and Genentech. P.J. received consultancy fees from Band/Guardian Therapeutics, Star/Vega Therapeutics, Roche, and BioMarin Pharmaceuticals. M.N. received research grants or lecture fees from Roche Diagnostics, Siemens Healthineers, Werfen, Stago, Technoclone, Pentapharm, Buhlmann laboratories, Sysmex, Euroimmun, Bayer Healthcare, and Viatris. J.G. received honoraria, advisory boards, and scientific support from CSL Behring, Takeda, Novartis, SOBI, and Amgen. G.L. received research funding from BioMarin and teaching honoraria from Sobi, Sanofi, Abbvie, Novo Nordisk, Alexion, Novartis, and Takeda. J.O.D. has served on the speaker’s bureau for Baxter, Bayer, Novo Nordisk, Sobi, Boehringer Ingelheim, Leo Pharma, Takeda, and Octapharma; served on the advisory boards of Baxter, Sobi, Bayer, Octapharma CSL Behring, Daiichi Sankyo, Boehringer Ingelheim, Takeda, and Pfizer; and received research grant funding awards from 3M, Baxter, Bayer, Pfizer, Shire, Takeda, and Novo Nordisk. Other authors declared no conflict of interest., (Copyright © 2024 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

A bleeding tendency is one of the most common complaints observed by hematologists. It is challenging to differentiate a clinically insignificant bleeding from a bleeding phenotype that requires hemostatic evaluation and medical intervention. A thorough review of personal and familial history, objective assessment of bleeding severity using a bleeding assessment tool, and a focused physical examination are critical to correctly identifying suspected patients with mild to moderate bleeding disorders (MBDs). A basic laboratory work-up should be performed in all patients referred for a bleeding tendency. If a hemostatic abnormality is found such as evidence of von Willebrand disease, a platelet function disorder, or a coagulation factor deficiency, more extensive testing should be performed to further characterize the bleeding disorder. Conversely, if all results are normal the patient is considered to have bleeding disorder of unknown cause (BDUC). For patients with BDUC, further evaluation may include non-routine testing to look for rare bleeding disorders not detected by routine hemostasis tests, such as thrombomodulin-associated coagulopathy, tissue factor pathway inhibitor-related bleeding disorder, hyperfibrinolytic-bleeding disorders or impaired tissue factor production. In this review, we summarize the stepwise diagnostic procedure in MBDs and provide some insights into the biological features of BDUC., (© 2024 The Authors. International Journal of Laboratory Hematology published by John Wiley & Sons Ltd.)

Yellow fever (YF) is an acute tropical infectious disease caused by an arbovirus and can manifest as a classic hemorrhagic fever. The mechanism of the bleeding diathesis in YF is not well understood. We assessed clinical and laboratory data (including a panel of coagulation tests) from 46 patients with moderate (M) and severe (S) YF admitted to a local hospital between January 2018 and April 2018. Among 46 patients, 34 had SYF of whom 12 (35%) patients died. A total of 21 (45%) patients developed some type of bleeding manifestation and 15 (32%) presented severe bleeding. Patients with SYF had more severe thrombocytopenia (p = 0.001); prolonged activated partial thromboplastin time (aPTT) and thrombin time (TT) (p = 0.03 and p = 0.005, respectively); reduced plasma levels of coagulation factor (F) II (p < 0.01), FIX (p = 0.01), and FX (p = 0.04); and D-dimer levels almost 10 times higher (p < 0.01) when compared with patients with MYF. Patients who died had more bleeding (p = 0.03), more major bleeding (p = 0.03), prolonged international normalized ratio (INR) and aPTT (p = 0.003 and p = 0.002, respectively), as well as lower activity of FII (p = 0.02), FV (p = 0.001), FVII (p = 0.005), FIX (p = 0.01), and protein C (p = 0.01) than the ones who survived. FVIII levels were either normal or increased in all patients studied. Our results suggest that the bleeding diathesis of SYF is associated with the deficiency of coagulation factors produced by the liver. Prolonged INR and aPTT and reduced FII, FV, FVII, FIX, and protein C were associated with death., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Iron deficiency anemia is associated with heavy menstrual bleeding (HMB) and, by extension, a bleeding disorder (BD). It is unknown if iron deficiency without anemia is associated with a BD in adolescents. Moreover, the threshold of ferritin associated with fatigue in adolescents with HMB is unclear. In this multicenter study, we enrolled adolescents with HMB without BD. Participants underwent BD and anemia work-up in Young Women's Hematology Clinics and completed the Peds QL™ fatigue scale. BDs were defined as von Willebrand Disease, platelet function defect, clotting factor deficiencies, and hypermobility syndrome. Two hundred and fifty consecutive adolescents were enrolled, of whom 196 met eligibility criteria. Overall, 43% (95% confidence interval: 36%-50%) were diagnosed with BD. A total of 61% (n = 119) had serum ferritin levels < 15 ng/mL, 23.5% (n = 46) had iron deficiency only, and 37% (n = 73) had iron deficiency anemia. Low ferritin or ferritin dichotomized as < 15 or ≥ 15 ng/mL was not associated with BD on univariable analysis (p = .24) or when accounting for age, race, ethnicity, body mass index, and hemoglobin (p = .35). A total of 85% had total fatigue score below the population mean of 80.5, and 52% (n = 102) were > 2 SD (or < 54) below the mean, the cut-off associated with severe fatigue. A ferritin threshold of < 6 ng/mL had a specificity of 79.8% but a sensitivity of 36% for severe fatigue. In conclusion, iron deficiency without anemia is not a predictor of BD in adolescents with HMB in a specialty setting. Severe fatigue, especially sleep fatigue, is prevalent in adolescents with BD. Ferritin of < 6 ng/mL has ~80% specificity for severe fatigue in adolescents with HMB., (© 2021 Wiley Periodicals LLC.)

Introduction: There is an unmet need to characterize the diagnosis and management of patients with an unclassified bleeding disorder (UBD)., Methods: Retrospective review of registered patients with UBD at our centre. Assessment including rotational thromboelastometry (ROTEM) and thrombin generation (TG) were used., Results: A total of 124 patients were identified; 91% female. Mean age of presentation was 38.3 years. Mean bleeding score was 8.8 (standard deviation [SD] 3.8); 6.6 in men (SD 1.4) and 9.7 in women (SD 3.3), which was significantly different (P < .05). In women, after deduction of scores for menorrhagia and postpartum haemorrhage, the mean score was 6.4 which was not significantly different to the male score (P = .11). Twenty-three percent of patients have been transfused, 61% women had treatment for menorrhagia and 17% for epistaxis. TxA and desmopressin were effective at preventing bleeding in 69 procedures and 13 deliveries. TG revealed 26% patients with a long lag time and 19% with a decreased endogenous thrombin potential but no diagnostic pattern was seen. ROTEM (NATEM) was unable to characterize patients; 9% had a prolonged clot time or maximum lysis. ThromboGenomics was normal in 45 tested patients., Conclusions: We provide data which shows the bleeding score is biased towards gynaecological bleeding but which remains elevated even when the bleeding score is deducted. Tranexamic acid and desmopressin are effective as haemostatic prophylaxis but there is an urgent need for clinical trials. In conclusion, we describe the use of the bleeding score in these patients and phenotype, diagnosis (including ThromboGenomic testing) and management with practice recommendations., (© 2019 John Wiley & Sons Ltd.)

Maintaining normal hemostasis relies on a regulated system of procoagulant and anticoagulant pathways, and disruption of these processes leads to the loss of hemostatic control, with the potential for excessive bleeding or thrombosis. Evaluation of bleeding disorders has conventionally been achieved by laboratory assays that measure the activity of individual coagulation factors. While such assays have proven effective for detecting abnormalities of the coagulation system and aiding diagnosis, inherent limitations prevent them from capturing a complete picture of hemostatic function. An improved understanding of thrombin activity and its central role in hemostasis and bleeding disorders has led to the clinical development of global assays that are more physiologically relevant than traditional assays; furthermore, these global assays are able to monitor responses to therapy. In this review, we provide an overview of the role of thrombin in hemostasis, and describe the clinical benefits of thrombin monitoring in patients with bleeding disorders. Moreover, we discuss recent advances in thrombin-targeting therapeutic strategies that aim to correct thrombin deficiency and prevent bleeding in patients with hemophilia and other rare bleeding disorders., (Published by Elsevier Ltd.)

Deficiencies or excessive activation of the  fibrinolytic system can result in severe, lifelong bleeding disorders. The most severe clinical phenotype is caused by α2-Antiplasmin (α2-AP) deficiency which results in excess fibrinolysis due to the inability to inhibit plasmin. Another bleeding disorder due to a defect in the fibrinolytic pathway results from Plasminogen activator inhibitor-1 (PAI-1) deficiency causing enhanced fibrinolysis due to the decreased inhibition of plasminogen activators resulting in increased conversion of plasminogen to plasmin. Both these disorders are rare and have an autosomal recessive pattern of inheritance. They can remain undetected as routine coagulation and platelet function tests are normal. A unique gain-of-function defect in fibrinolysis causes the Quebec platelet disorder (QPD) which is characterized by profibrinolytic platelets containing increased urokinase-type plasminogen activator (uPA) in the α-granules. A high index of suspicion based on clinical phenotype along with the availability of specialized hemostasis testing is required for timely and accurate diagnosis. Antifibrinolytic agents, such as tranexamic acid or ε-aminocaproic acid, are the mainstays of treatment which inhibit fibrinolysis by preventing the binding of plasminogen to fibrin and thereby stabilizing the fibrin clot. The purpose of this review is to summarize the pathogenesis, clinical phenotype, approaches to diagnosis and treatment for these three major disorders of fibrinolysis., (Copyright © 2019. Published by Elsevier Ltd.)

Background: In a large proportion of patients with a mild to moderate bleeding tendency no diagnosis can be established (bleeding of unknown cause, BUC)., Objectives: To investigate possible dysfunctions in thrombin generation and plasma clot formation and lysis in patients with BUC from the Vienna Bleeding Biobank (VIBB)., Patients and Methods: Thrombin generation and plasma clot properties of 382 BUC patients were compared to those of 100 healthy controls and 16 patients with factor VIII (FVIII) activity ≤50%., Results: Thrombin generation was significantly impaired in BUC patients compared to healthy controls, exhibiting a prolonged lag time and time to peak and decreased maximum thrombin generation, velocity index, and area under the curve (AUC). The assessment of clot formation and lysis in BUC patients revealed a lower clot formation rate (Vmax), resulting in a longer TTP, increased absorbance (ΔAbs), and a shorter clot lysis time (CLT) than in healthy controls. Comparing patients with FVIII activity ≤ 50% to those with BUC, parameters of thrombin generation and clot formation and lysis were either stronger or comparably impaired. Bleeding severity did not correlate with parameters of thrombin generation, clot formation, or clot lysis., Conclusion: Patients with BUC have an impaired hemostatic capacity reflected by a lower thrombin-generation potential, a lower clot formation rate, increased clot turbidity, and shorter clot lysis time, which might contribute to their increased bleeding tendency. Assays monitoring these parameters can alert physicians of hemostatic impairment and should be considered in situations where traditional hemostatic lab tests fail to reveal the clinical bleeding tendency., (© 2019 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

A 9-year-old mixed breed 13 kg spayed female dog was presented for evaluation of two masses in the right abdominal mammary gland region. Surgery was conducted to excise the masses. A grade I complex mammary gland carcinoma and high grade (grade III) mast cell tumor with an inguinal lymph node metastasis were diagnosed. Forty-seven days after the surgical procedure, the mast cell tumor relapsed, and neoadjuvant treatment with lomustine (81 mg/m 2 ) was prescribed. Thirteen days from initiation of lomustine therapy, the dog was re-presented to the hospital with bloody diarrhea, hematemesis, epistaxis, an elevated rectal temperature, depression, severe dehydration, and marked dyspnea. The CBC showed severe thrombocytopenia and leukopenia. According to the owner, lomustine (45mg per os [PO]) was mistakenly administered daily for 10 consecutive days (total dose, 810 mg/m 2 ). The dog died and a necropsy was performed. The main gross lesions consisted of severe multifocal hemorrhages in multiple organs, especially in the digestive system. Histopathologic evaluation revealed disseminated hemorrhages, as well as marked bone marrow aplasia. This report describes the clinical, hematologic, gross, and histologic findings in a fatal case of lomustine overdose in a dog., (© 2019 American Society for Veterinary Clinical Pathology.)

Background: Major guidelines emphasise the potential of visco-elastic methods to overcome the limitations of conventional laboratory assays in the peri-operative setting. Their sensitivity regarding mild bleeding disorders (MBDs), the most common bleeding disorders in the general population, is however unknown., Objective: The aim of this study was to investigate the sensitivity of thromboelastometry for diagnosis of MBD., Design: A single-centre prospective cohort study., Setting: Haematology outpatient unit of a tertiary general hospital in Central Switzerland., Patients: All consecutive patients referred over a 32-month period with a suspected bleeding disorder were included and thromboelastometry was conducted using a ROTEM delta (EXTEM, INTEM and FIBTEM). Diagnostic work-up was performed according to current guidelines including the ISTH bleeding assessment tool (ISTH BAT)., Main Outcome Measures: Distribution of clotting time (CT) and maximum clot firmness (MCF) results in relation to the presence of MBD., Results: Two hundred and seventeen patients were assessed; the median [IQR] age was 39 years [28 to 57]; 151 patients were women (70%). MBD was diagnosed in 97 patients (45%), no MBD was found in 100 patients (46%) and a systemic disorder recognised in 20 patients (9%). Presence of MBD was not associated with a significant difference in thromboelastometry variables (0.2 s in CT EXTEM, 95% CI -2.3 to 2.7; -0.2 mm in MCF EXTEM, 95% CI -1.8 to 1.5; -0.7 s in CT INTEM, 95% CI -12.6 to 11.2; 0.6 mm in MCF INTEM, 95% CI -1.2 to 1.3; 0.8 mm in MCF FIBTEM, 95% CI -1.6 to 1.4) and most results were within the established reference ranges., Conclusion: Our data did not support the use of thromboelastometry as a diagnostic tool in patients with MBD.

Introduction: In systemic lupus erythematosus, hemostasis disorders are mainly thrombotic, but more rarely hemorrhagic., Case Report: A 25-year-old man presented with a macrophagic activation syndrome revealing a systemic lupus erythematosus, secondarily complicated by a hemorrhagic syndrome ; biological investigations revealed an increase thrombin time and an activated partial thromboplastin time, normalized by protamin neutralization in vitro, thus confirming the presence of a heparin-like anticoagulant. The hemostasis balance normalized after the specific treatment of lupus., Conclusion: This rare anomaly of hemostasis balance has been described in blood cancers and solid cancers. This is the first description of a case associated with an autoimmune connective tissue disorder such as lupus. After one year of follow-up, no diagnosis of blood or solid cancer was made., (Copyright © 2018 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.)

Children with an unexplained bleeding tendency are frequently referred to a haemostaseologist for further evaluation. Careful standardized history taking and clinical evaluation should allow for distinguishing bleeds after minor injury and trauma which are very common in all children. However, in two groups of children bleeding symptoms may be more significant than expected: those with an underlying coagulation disorder and those who have been subjected to physical child abuse. The coexistence of child abuse and a bleeding disorder must always be considered. An extended coagulation diagnostic is required if the morphology of bleedings is not clearly suspicious for child abuse and in the absence of typical concomitant injuries, e.g., bone fractures. An interdisciplinary approach involving a forensic pathologist and a paediatric haemostaseologist for assessment of bleeding symptoms, the explanation of the clinical findings, and the critical evaluation of laboratory results are essential in such cases. This review is focussed on symptoms in accidental and nonaccidental injuries in children assisting haemostaseologists in decision making in cases of child protection issues., Competing Interests: On behalf of all co-authors the first and the senior author declare no conflicts of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

Objective: To describe the implantation of a care quality indicator associated to the nursing diagnosis of patients at high risk of bleeding, based on the alarming results of prothrombin time (PT), partially activated thromboplastin time (aPTT) and platelets., Methods: Retrospective experience report of multidisciplinary actions developed in a university hospital. The stages of the study involved team meetings, search for effective communication strategies and creation of a new indicator of quality of care., Results: The indicator was called "Compliance of Nursing Diagnosis Risk for bleeding", monitored monthly since June 2016. The technical file includes the characteristics and attributes of the indicator. Based on the analyzes of the indicator, action plans are established for its qualification., Conclusion: The implementation of the quality of care indicator associated to the nursing diagnosis improved the communication process, the monitoring and the nursing care to patients at risk of bleeding.

Objective: To elucidate conditions which cause elevation of the serum ferritin, extent of the elevation in each condition, and clinical relevance of hyperferritinemia in general practice., Methods: We retrospectively studied medical records of all patients who had at least one serum ferritin measurement above 500 μg L -1 . Patients who had a marked elevation of the serum ferritin over 10,000 μg L -1 were studied separately., Results: We studied 1394 patients to identify the etiologies of hyperferritinemia. Median serum ferritin level was 1024 μg L -1 and 49.2% had ferritin levels of 501-1000 μg L -1 . The most frequent cause of hyperferritinemia was non-human immunodeficiency virus infection followed by solid tumor, liver dysfunction, renal failure, and hematological malignancy. The distributions of the causes were different among groups stratified by the ferritin level. Forty-one percent had multiple causes and there was a tendency that the more underlying causes a patient had, the higher the ferritin level. Each condition led to a wide range of the ferritin level, and some patients could present with marked hyperferritinemia. Seventy percent of 111 patients with marked hyperferritinemia had multiple etiologies and a variety of diseases could lead to marked hyperferritinemia by themselves., Discussion: Patients with hyperferritinemia frequently had multiple conditions. The level of the serum ferritin was determined by the underlying conditions to a certain extent; however, the variation was significant. While patients with marked hyperferritinemia mostly had multiple underlying causes, various diseases could cause hyperferritinemia by themselves., Conclusion: Hyperferritinemia is associated with both etiology and the number of underlying causes.

Platelet count represents a useful tool in clinical practice to discriminate individuals at higher risk of bleeding. Less obvious is the role of platelet count variability within the normal range of distribution in shaping the individual's disease risk profile. Epidemiological studies have shown that platelet count in the adult general population is associated with a number of health outcomes related to hemostasis and thrombosis. However, recent studies are suggesting a possible role of this platelet index also as an independent risk factor. In this review of adult population studies, we will first focus on known genetic and non-genetic determinants of platelet number variability. Next, we will evaluate platelet count as a marker and/or a predictor of disease risk and its interaction with other risk factors. We will then discuss the role of platelet count variability within the normal distribution range as a contribution to disease and mortality risk. The possibility of considering platelet count as a simple, inexpensive indicator of increased risk of disease and death in general populations could open new opportunities to investigate novel platelet pathophysiological roles as well as therapeutic opportunities. Future studies should also consider platelet count, not only platelet function, as a modulator of disease and mortality risk., (© 2018 International Society on Thrombosis and Haemostasis.)

The RASGRP2 gene encodes the Ca 2+ and DAG-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), which plays a key role in integrin activation in platelets and neutrophils. We here report two new RASGRP2 variants associated with platelet dysfunction and bleeding in patients. The homozygous patients had normal platelet and neutrophil counts and morphology. Platelet phenotyping showed: prolonged PFA-100 closure times; normal expression of major glycoprotein receptors; severely reduced platelet aggregation response to ADP and collagen (both patients); aggregation response to PAR1 and arachidonic acid markedly impaired in one patient; PMA-induced aggregation unaffected; platelet secretion, clot retraction, and spreading minimally affected. Genetic analysis identified two new homozygous variants in RASGRP2: c.706C>T (p.Q236X) and c.887G>A (p.C296Y). In both patients, CalDAG-GEFI protein was not detectable in platelet lysates, and platelet αIIbβ3 activation, as assessed by fibrinogen binding, was greatly impaired in response to all agonists except PMA. Patient neutrophils showed normal integrin expression, but impaired Mn 2+ -induced fibrinogen binding. In summary, we have identified two new RASGRP2 mutations that can be added to this rapidly growing form of inherited platelet function disorder.

Objective: To determine the accuracy and usefulness of noninvasive continuous hemoglobin (Hb) monitoring in critically ill patients at risk of bleeding., Design: An observational prospective study was made, comparing core laboratory Hb measurement (LabHb) as the gold standard versus transcutaneous hemoglobin monitoring (SpHb)., Setting: Pediatric Intensive Care Unit of a tertiary University Hospital., Patients: Patients weighing >3kg at risk of bleeding., Interventions: SpHb was measured using the Radical7 pulse co-oximeter (Masimo Corp., Irvine, CA, USA) each time a blood sample was drawn for core laboratory analysis (Siemens ADVIA 2120i)., Variables: Sociodemographic characteristics, perfusion index (PI), pleth variability index, heart rate, SaO 2 , rectal temperature, low signal quality and other events that can interfere with measurement., Results: A total of 284 measurements were made (80 patients). Mean LabHb was 11.7±2.05g/dl. Mean SpHb was 12.32±2g/dl (Pearson 0.72, R 2 0.52). The intra-class correlation coefficient was 0.69 (95%CI 0.55-0.78)(p<0.001). Bland-Altman analysis showed a mean difference of 0.07 ±1.46g/dl. A lower PI and higher temperature independently increased the risk of low signal quality (OR 0.531 [95%CI 0.32-0.88] and 0.529 [95%CI 0.33-0.85], respectively)., Conclusions: SpHb shows a good overall correlation to LabHb, though with wide limits of agreement. Its main advantage is continuous monitoring of patients at risk of bleeding. The reliability of the method is limited in cases with poor peripheral perfusion., (Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.)

There are conflicting reports on whether or not laboratory abnormalities in pediatric acquired von Willebrand syndrome (AVWS) predict bleeding manifestations in patients with cardiopulmonary disorders (CPD). We retrospectively reviewed charts of patients with AVWS and CPD (n=16) seen at Texas Children's Hospital from 2003 to 2012. The most common CPD were valve stenoses, ventricular septal defects, and pulmonary hypertension. All patients had loss of high molecular weight multimers. Fifteen (94%) patients presented with bleeding symptoms, with menorrhagia and epistaxis being the most common. Von Willebrand ristocetin cofactor activity (VWF:RCo), as well as the use of anticoagulant or antiplatelet medication, did not predict bleeding manifestations (P=0.70 and 0.84, respectively). VWF:RCo/VWF antigen (Ag) ratio of <0.7 was significantly associated with presence of bleeding symptoms. All patients who had complete repair of their cardiac defect experienced normalization of VWF multimers and VWF:RCo/Ag ratio, as well as bleeding symptom resolution. We conclude that increased bleeding risk is associated with low VWF:RCo/Ag ratio in pediatric AVWS due to CPD. However, other laboratory abnormalities such as VWF:RCo level and qualitative multimer analysis, do not appear to predict bleeding. Future studies exploring quantification of multimer loss may be helpful in further assessing bleeding risk associations.

In patients with thrombocytopenia, it can be difficult to predict a patient's bleeding risk based on platelet count alone. Platelet reactivity may provide additional information; however, current clinical assays cannot reliably assess platelet function in the setting of thrombocytopenia. New methods to study platelet reactivity in thrombocytopenic samples are needed. In this study, we sought to develop a laboratory model of thrombocytopenia using blood from healthy subjects that preserves the whole blood environment and reproducibly produces samples with a specific platelet count and hematocrit. We compared the activation state of unstimulated and agonist-stimulated platelets in thrombocytopenic samples derived from this method with normocytic controls. Whole blood was diluted with autologous red blood cell concentrate and platelet-poor plasma, which were obtained via centrifugation, in specific ratios to attain a final sample with a predetermined platelet count and hematocrit. P-selectin exposure and GPIIbIIIa activation in unstimulated platelets and platelets stimulated with collagen-related peptide (CRP) or adenosine diphosphate (ADP) in thrombocytopenic samples and the normocytic control from which they were derived were quantified by flow cytometry. Our methodology reliably produced thrombocytopenic samples with a platelet count ≤50,000/μL and an accurately and precisely controlled hematocrit. P-selectin exposure and GPIIbIIIa activation on unstimulated platelets or on ADP- or CRP-stimulated platelets did not differ in thrombocytopenic samples compared to normocytic controls. We describe a new method for creating thrombocytopenic blood that can be used to better understand the contributions of platelet number and function to hemostasis.

The evaluation of patients with a bleeding tendency represents a challenge as the routinely available tests for evaluating bleeding disorders are limited, complicating the laboratory determination of the clinically observed bleeding tendency. As a result, some bleeding disorders remain undiagnosed. The aim of the study was to evaluate whether global coagulation tests would contribute to the laboratory analysis of patients with undiagnosed bleeding disorders. Patients were evaluated for coagulation and fibrinolysis activities by thrombin generation test and euglobulin lysis time. In addition, plasma activity of factor XIII, plasminogen, α-2 antiplasmin, plasminogen activator inhibitor-1, and thrombin-activatable fibrinolysis inhibitor was also obtained. Forty-five patients were included. Eight per cent presented a mild bleeding disorder and 20% a moderate bleeding disorder. The thrombin generation test results were similar between patients and controls. Euglobulin lysis time results, however, were lower in patients than in controls, both before (median 175 vs. 250 min, respectively; P = 0.003) and after (median 145 vs. 115 min, respectively; P ≤ 0.001) arm constriction, suggesting that they were experiencing hyperfibrinolysis. Interestingly, patients' median thrombin-activatable fibrinolysis inhibitor activity was higher than in controls (21.2 vs. 19.46 μg/ml; P = 0.016). However, plasminogen, α-2 antiplasmin, plasminogen activator inhibitor-1, and factor XIII activities did not differ between the groups. Global coagulation and fibrinolysis tests proved to be limited in detecting the hemostatic disorders in some patients with a relevant bleeding tendency and may not be adequate to address their bleeding risk. Bleeding scores are currently the available medical approach for the evaluation of these patients.

Functional disorders of platelets can involve any aspect of platelet physiology, with many different effects or outcomes. These include platelet numbers (thrombocytosis or thrombocytopenia); changes in platelet production or destruction, or capture to the liver (Ashwell receptor); altered adhesion to vascular injury sites and/or influence on hemostasis and wound healing; and altered activation or receptor functions, shape change, spreading and release reactions, procoagulant and antifibrinolytic activity. Procoagulant membrane alterations, and generation of thrombin and fibrin, also affect platelet aggregation. The above parameters can all be studied, but standardization and quality control of assay methods have been limited despite several efforts. Only after a comprehensive clinical bleeding assessment, including family history, information on drug use affecting platelets, and exclusion of coagulation factor, and tissue deficits, should platelet function testing be undertaken to confirm an abnormality. Current diagnostic tools include blood cell counts, platelet characteristics according to the cell counter parameters, peripheral blood smear, exclusion of pseudothrombocytopenia, whole blood aggregometry (WBA) or light transmission aggregometry (LTA) in platelet-rich plasma, luminescence, platelet function analysis (PFA-100) for platelet adhesion and deposition to collagen cartridges under blood flow, and finally transmission electron microscopy to exclude rare structural defects leading to functional deficits. The most validated test panels are included in WBA, LTA, and PFA. Because platelets are isolated from their natural environment, many simplifications occur, as circulating blood and interaction with vascular wall are omitted in these assays. The target to reach a highly specific platelet disorder diagnosis in routine clinical management can be exhaustive, unless needed for genetic counseling. The elective overall assessment of platelet function disorder primarily aims at better management of hemostasis in case of emergency surgery or other interventions and acute bleeding events., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective: Mild bleeding symptoms are commonly seen in the general population. The aim of this study was to determine the final clinical and laboratory features of children referred for a first evaluation with a suspected bleeding disorder in the pediatric outpatient clinic of İstanbul University., Materials and Methods: The medical records of 26,737 outpatients who were admitted to the Division of Ambulatory Pediatrics between 31 October 2011 and 31 October 2012 were evaluated retrospectively. Ninety-nine patients were initially diagnosed as having probable bleeding disorders and were followed up. The symptoms of bleeding in addition to coagulation tests were analyzed., Results: Of the 99 patients, 52 (52.5%) were male and 47 were female, and the mean age of the entire study group was 9.1±4.1 years (minimum-maximum: 2-18 years). Major bleeding symptoms were epistaxis in 36 patients (36.4%), easy bruising in 32 (32.3%), and menorrhagia in 6 (6.1%). After initial tests ordered by the pediatrician, 36 of 99 patients (36.4%) were diagnosed as having bleeding disorders that included von Willebrand disease in 12 (12.1%), hemophilia A or B in 9 (9.1%), and other rare factor deficiencies in 9 (9.1%). Six patients (6.1%) were found to have combined deficiencies. Seven of 36 patients had a family history of bleeding., Conclusion: Among the patients referred for bleeding disorders, 36.4% were diagnosed with a bleeding disorder with the help of primary screening tests ordered in the outpatient clinic.

Background: Very premature infants are at high risk of bleeding complications; however, few data exist on ranges for standard coagulation tests., Objectives: The primary objective of this study was to measure standard plasma coagulation tests and thrombin generation in very premature infants compared with term infants. The secondary objective was to evaluate whether an association existed between coagulation indices and intraventricular hemorrhage (IVH)., Patients/methods: Cord and peripheral blood of neonates < 30 weeks gestational age (GA) was drawn at birth, on days 1 and 3 and fortnightly until 30 weeks corrected gestational age. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and coagulation factor levels were measured and tissue factor-stimulated thrombin generation was characterized. Control plasma was obtained from cord blood of term neonates., Results: One hundred and sixteen infants were recruited. Median (range) GA was 27.7 (23.7-29.9) weeks and mean (SD) birth weight was 1020 (255) g. Median (5th-95th percentile) day 1 PT, APTT and fibrinogen were 17.5 (12.7-26.6) s, 78.7 (48.7-134.3) s and 1.4 (0.72-3.8) g L(-1) , respectively. No difference in endogenous thrombin potential between preterm and term plasma was observed, where samples were available. Levels of coagulation factors II, VII, IX and X, protein C, protein S and antithrombin were reduced in preterm compared with term plasma. Day 1 APTT and PT were not associated with IVH., Conclusion: In the largest cross-sectional study to date of very preterm infants, typical ranges for standard coagulation tests were determined. Despite long clotting times, thrombin generation was observed to be similar in very preterm and term infants., (© 2015 International Society on Thrombosis and Haemostasis.)

Background/aims: This study investigated whether patients with acute promyelocytic leukemia (APL) truly fulfill the diagnostic criteria of overt disseminated intravascular coagulation (DIC), as proposed by the International Society on Thrombosis and Haemostasis (ISTH) and the Korean Society on Thrombosis and Hemostasis (KSTH), and analyzed which component of the criteria most contributes to bleeding diathesis., Methods: A single-center retrospective analysis was conducted on newly diagnosed APL patients between January 1995 and May 2012., Results: A total of 46 newly diagnosed APL patients were analyzed. Of these, 27 patients (58.7%) showed initial bleeding. The median number of points per patient fulfilling the diagnostic criteria of overt DIC by the ISTH and the KSTH was 5 (range, 1 to 7) and 3 (range, 1 to 4), respectively. At diagnosis of APL, 22 patients (47.8%) fulfilled the overt DIC diagnostic criteria by either the ISTH or KSTH. In multivariate analysis of the ISTH or KSTH diagnostic criteria for overt DIC, the initial fibrinogen level was the only statistically significant factor associated with initial bleeding (p = 0.035), but it was not associated with overall survival (OS)., Conclusions: Initial fibrinogen level is associated with initial presentation of bleeding of APL patients, but does not affect OS.

Background: Dietary cholesterol has been suggested to increase the risk of cardiovascular disease (CVD), which has led to US recommendations to reduce cholesterol intake., Objective: The authors examine the effects of dietary cholesterol on CVD risk in healthy adults by using systematic review and meta-analysis., Design: MEDLINE, Cochrane Central, and Commonwealth Agricultural Bureau Abstracts databases were searched through December 2013 for prospective studies that quantified dietary cholesterol. Investigators independently screened citations and verified extracted data on study and participant characteristics, outcomes, and quality. Random-effect models meta-analysis was used when at least 3 studies reported the same CVD outcome., Results: Forty studies (17 cohorts in 19 publications with 361,923 subjects and 19 trials in 21 publications with 632 subjects) published between 1979 and 2013 were eligible for review. Dietary cholesterol was not statistically significantly associated with any coronary artery disease (4 cohorts; no summary RR), ischemic stroke (4 cohorts; summary RR: 1.13; 95% CI: 0.99, 1.28), or hemorrhagic stroke (3 cohorts; summary RR: 1.09; 95% CI: 0.79, 1.50). Dietary cholesterol statistically significantly increased both serum total cholesterol (17 trials; net change: 11.2 mg/dL; 95% CI: 6.4, 15.9) and low-density lipoprotein (LDL) cholesterol (14 trials; net change: 6.7 mg/dL; 95% CI: 1.7, 11.7 mg/dL). Increases in LDL cholesterol were no longer statistically significant when intervention doses exceeded 900 mg/d. Dietary cholesterol also statistically significantly increased serum high-density lipoprotein cholesterol (13 trials; net change: 3.2 mg/dL; 95% CI: 0.9, 9.7 mg/dL) and the LDL to high-density lipoprotein ratio (5 trials; net change: 0.2; 95% CI: 0.0, 0.3). Dietary cholesterol did not statistically significantly change serum triglycerides or very-low-density lipoprotein concentrations., Conclusion: Reviewed studies were heterogeneous and lacked the methodologic rigor to draw any conclusions regarding the effects of dietary cholesterol on CVD risk. Carefully adjusted and well-conducted cohort studies would be useful to identify the relative effects of dietary cholesterol on CVD risk., (© 2015 American Society for Nutrition.)

Aim: To measure cerebral tissue hemoglobin in uncomplicated and complicated pregnant women during the peripartum period., Methods: Time-resolved spectroscopy (TRS-20) can measure absolute concentration of oxygenated, deoxygenated, and total tissue hemoglobin based on the transit time of individual photons. Therefore, we used TRS-20 to measured tissue hemoglobin in the hemi-prefrontal lobes of normotensive pregnant women with (n = 51) or without (n = 19) epidural anesthesia, hypertensive pregnant women with pre-eclampsia (n = 10), a pregnant woman with acute onset of hypertension soon after delivery, and a hypertensive woman after hemorrhagic stroke in delivery., Results: Cyclic labor concomitant with intra-abdominal pressure caused synergistic elevation in cerebral tissue hemoglobin. In contrast, epidural anesthesia reduced the amplitude of the cyclic increase of cerebral tissue hemoglobin in normotensive pregnant women. Hypertension in labor due to pre-eclampsia increased the amplitude of synergistic elevation of cerebral tissue hemoglobin caused by cyclic labor and intra-abdominal pressure. A prolonged high basal level of cerebral tissue hemoglobin was observed in a case of acute onset of hypertension soon after delivery. A decrease in cerebral tissue hemoglobin in the hemi-prefrontal lobe was observed in a woman 2 h after the onset of hemorrhagic stroke in labor., Conclusions: TRS-20 can detect specific changes in maternal cerebral tissue hemoglobin level in response to physiological and pathophysiological changes in delivery. Thus, it represents a promising new conventional tool for maternal cerebral monitoring in the peripartum period., (© 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.)

Background: Evidences suggest an association between leukocytosis and thrombotic or hemorrhagic complication in polycythemia vera (PV) and essential thrombocythemia (ET), but clinical implication is not well known., Objective: To evaluate whether leukocyte burden during follow-up is related to thrombotic or hemorrhagic events in PV and ET., Patients/methods: We retrospectively analyzed patients with PV or ET treated at Seoul National University Bundang Hospital, Korea. Time-weighted averages of leukocytes during the follow-up period were defined as leukocyte burden and were calculated for each patient and compared between patient subgroups. In each patient with events, leukocyte burden for the 3-month period before the event was compared with that for the entire follow-up period., Results: In 102 patients with PV or ET, 35 events (16 thrombotic, 19 hemorrhagic) occurred in 29 patients (median follow-up, 54months). Leukocyte burden were significantly higher in patients with events than in event-free patients (12,015×10(3) /μL vs. 9,567×10(3)/μL, P=0.003). The difference was more prominent in ET patients than in PV patients, and in patients with hemorrhagic events than in those with thrombotic events. In patients with events, the leukocyte burden in the pre-event period was higher than in the entire follow-up period (16,767×10(3)/μL vs. 12,015×10(3)/μL, P=0.002). In all patients, leukocyte burden during entire follow-up period of 11,000×10(3)/μL or higher was an independent risk factor for vascular events., Conclusion: In PV or ET patients, leukocyte burden during disease course is related to increased incidence of thrombotic or hemorrhagic events., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Metabolic acidosis has been implicated in the development of coagulopathy, although the specific mechanisms have not been well characterized. We sought to explore whether resuscitation of injured patients with a balanced crystalloid solution affects coagulation, as measured by endogenous thrombin potential (ETP) and thromboelastography (TEG). We performed an exploratory analysis of a subset of subjects enrolled in a randomized trial comparing the effect of resuscitation with isotonic saline versus Plasma-Lyte A (PLA) on acidosis and electrolyte abnormalities. We collected plasma at admission and 6 h later for subsequent ETP and TEG analysis and compared subjects receiving isotonic saline to those receiving PLA. Among 18 evaluated subjects, baseline characteristics, including ETP and TEG parameters, were similar between the two arms. At 6 h, subjects receiving isotonic saline were more acidemic. At 6 h, there were no differences in ETP parameters between groups; however, TEG results showed the time from initial clot formation to an amplitude of 20 mm (K) was shorter (3.8 ± 2.1 vs. 7.2 ± 2.8 s) and the rapidity of fibrin build-up and cross-linking (α angle) was significantly greater (41 ± 8 vs. 24 ± 15 deg) for the PLA group than in the isotonic saline group. Relative to PLA, isotonic saline does not alter thrombin generation, but isotonic saline and PLA may differentially impact clotting factor availability. The shorter time to reach prespecified clot amplitude and the increased rate of fibrin generation imply faster amplification of clotting factors with PLA without effect on latency time or clot strength.

We assessed an in-vitro model of hyperfibrinolysis using rotational thromboelastometry (ROTEM) by the addition of increasing concentrations of tissue-type plasminogen activator (t-PA) on whole blood obtained from children undergoing cardiac surgery. We assessed the relevance of this model by repeating the tests in the same population after tranexamic acid (TXA) infusion. In addition, we determined the sensitivity and specificity of ROTEM parameters to detect the different degrees of fibrinolysis. Blood samples obtained from 20 children were analyzed at two predefined timepoints: after induction of anesthesia, before TXA (baseline), and at the end of surgery during TXA infusion (end surgery). At baseline, an extrinsic activation with tissue factor (EXTEM) test was performed without and with increasing concentration of t-PA (102, 255, 512, 1024, 1535, and 2539 units t-PA/ml). At the end of surgery, a second EXTEM test was performed without and with two different t-PA concentrations (1535 and 2539 units t-PA/ml). At baseline, increasing t-PA concentrations in the EXTEM test induced a gradual increase of hyperfibrinolysis characterized by a reduction in clot firmness and stability parameters. In the presence of TXA, t-PA-induced hyperfibrinolysis was completely abolished. Lysis-onset time (LOT) and degree of fibrinolysis measured at 30 min (LI30) best assessed the degree of fibrinolysis. This in-vitro model of t-PA-induced hyperfibrinolysis using the EXTEM test of ROTEM may represent a promising tool to assess hyperfibrinolysis in the pediatric population. In addition, we observed that LOT and LI30 should be considered as the best parameters to detect different degrees of fibrinolysis.

Women with mild bleeding disorders (MBDs) pose a diagnostic challenge and menorrhagia, the most common presenting symptom that remains underreported. We tested the hypothesis that screening apparently normal females using general and gynecological bleeding assessment tools and a global hemostatic assay together with platelet aggregation can help predict MBDs. We assessed 47 women using electronic bleeding assessment tools; e-bleeding questionnaire; and e-Pictorial Bleeding Assessment Chart (e-PBAC) based on previously validated methods, thrombelastography (TEG), and platelet aggregation together with basic coagulation testing. Three women had elevated bleeding score with von Willebrand disease diagnosis confirmed in one case and eleven cases had elevated e-PBAC. We report normal ranges for TEG and platelet aggregation in women during the first half of the menstrual cycle and show 23.4% of apparently normal women may have general or heavy menstrual bleeding. This is a prelude to a larger study to determine the validity of bleeding assessment tools in screening for MBDs in women., (© The Author(s) 2014.)

Background: A clinically relevant bleeding diathesis is a frequent diagnostic challenge, which sometimes remains unexplained despite extensive investigations. The aim of our work was to evaluate the diagnostic utility of functional platelet testing by flow cytometry in this context., Methods: In case of negative results after standard laboratory workup, flow cytometric analysis (FCA) of platelet function was done. We performed analysis of surface glycoproteins Ibα, IIb, IIIa; P-selectin expression and PAC-1 binding after graded doses of ADP, collagen, and thrombin; content/secretion of dense granules; and ability to generate procoagulant platelets., Results: Of 437 patients investigated with standard tests between January 2007 and December 2011, we identified 67 (15.3%) with high bleeding scores and nondiagnostic standard laboratory workup including platelet aggregation studies. Among these patients, FCA revealed some potentially causative platelet defects: decreased dense granule content/secretion (n = 13); decreased α-granule secretion induced by ADP (n = 10), convulxin (n = 4), or thrombin (n = 3); decreased fibrinogen receptor activation induced by ADP (n = 11), convulxin (n = 11), or thrombin (n = 8); and decreased generation of COAT platelets, that is, highly procoagulant platelets induced by simultaneous activation with collagen and thrombin (n = 16)., Conclusion: Our work confirms that storage pool defects are frequent in patients with a bleeding diathesis and normal coagulation and platelet aggregations studies. Additionally, FCA is able to identify discrete platelet activation defects. In particular, we show for the first time that a relevant proportion of these patients has an isolated impaired ability to generate COAT platelets--a conceptually new defect in platelet procoagulant activity, which is missed by conventional laboratory workup., (© 2014 Clinical Cytometry Society.)

We previously demonstrated that plasminogen activator inhibitor-1 (PAI-1), an inhibitor of fibrinolysis, is involved in type 1 diabetic bone loss in female mice. PAI-1 is well known as an adipogenic factor induced by obesity. We therefore examined the effects of PAI-1 deficiency on bone and glucose and lipid metabolism in high-fat and high-sucrose diet (HF/HSD)-induced obese female mice. Female wild-type (WT) and PAI-1-deficient mice were fed with HF/HSD or normal diet for 20 weeks from 10 weeks of age. HF/HSD increased the levels of plasma PAI-1 in WT mice. PAI-1 deficiency suppressed the levels of blood glucose, plasma insulin, and total cholesterol elevated by obesity. Moreover, PAI-1 deficiency improved glucose intolerance and insulin resistance induced by obesity. Bone mineral density (BMD) at trabecular bone as well as the levels of osterix, alkaline phosphatase, and receptor activator of nuclear factor κB ligand mRNA in tibia were decreased by HF/HSD in WT mice, and those changes by HF/HSD were not affected by PAI-1 deficiency. HF/HSD increased the levels of plasma TNF-α in both WT and PAI-1-deficient mice, and the levels of plasma TNF-α were negatively correlated with trabecular BMD in tibia of female mice. In conclusion, we revealed that PAI-1 deficiency does not affect the trabecular bone loss induced by obesity despite the amelioration of insulin resistance and hyperlipidemia in female mice. Our data suggest that the changes of BMD and bone metabolism by obesity might be independent of PAI-1 as well as glucose and lipid metabolism.

Coagulation disorders are frequently encountered in the intensive care unit (ICU) and are challenging due to a variety of potential etiologies. Critically ill patients with coagulation abnormalities may present with an increased risk of bleeding, show coagulation activation resulting in thromboembolism, or have no specific symptoms. Hemostatic abnormalities observed in ICU patients range from isolated thrombocytopenia or prolonged global clotting tests to complex and life-threatening coagulation defects. Successful management of coagulation disorders requires prompt and accurate identification of the underlying cause. This review describes the most frequently occurring diagnoses found in intensive care patients with thrombocytopenia and coagulation test abnormalities and summarizes appropriate diagnostic interventions and current approaches to differential diagnosis.

Background: Patients with acquired bleeding disorders are often a diagnostic challenge in internal medicine., Objectives: Which diagnostic work up is necessary in these patients and which coagulation tests are useful?, Material and Methods: Analysis and diagnostic workup in the daily practice are discussed according to review publications in this field and existing clinical evidence., Results: First important step is the bleeding history of the patient. The different signs of bleeding are important hints for the cause. The global assays Quick (PT) and PTT in combination with platelet count and function reveal a primary knowledge of the kind of the acquired bleeding disorder. In addition special coagulation tests normally lead to the exact diagnosis of the cause of bleeding., Conclusions: Patients with newly developed bleeding symptoms should be examined for acquired coagulation disorders. The clinical sings in combination with the special coagulation tests allow the correct diagnosis.

Background: A bleeding diathesis is a common feature of Noonan syndrome, and various coagulation abnormalities have been reported. Platelet function has never been carefully investigated., Methods: The degree of bleeding diathesis in a cohort of patients with Noonan syndrome was evaluated by a validated bleeding score and investigated with coagulation and platelet function tests. If ratios of prothrombin time and/or activated partial thromboplastin time were prolonged, the activity of clotting factors was measured. Individuals with no history of bleeding formed the control group., Results: The study population included 39 patients and 28 controls. Bleeding score was ≥2 (ie, suggestive of a moderate bleeding diathesis) in 15 patients (38.5%) and ≥4 (ie, suggestive of a severe bleeding diathesis) in 7 (17.9%). Abnormal coagulation and/or platelet function tests were found in 14 patients with bleeding score ≥2 (93.3%) but also in 21 (87.5%) of those with bleeding score <2. The prothrombin time and activated partial thromboplastin time were prolonged in 18 patients (46%) and partial deficiency of factor VII, alone or in combination with the deficiency of other vitamin K-dependent factors, was the most frequent coagulation abnormality. Moreover, platelet aggregation and secretion were reduced in 29 of 35 patients (82.9%, P < .01 for all aggregating agents)., Conclusions: Nearly 40% of patients with the Noonan syndrome had a bleeding diathesis and >90% of them had platelet function and/or coagulation abnormalities. Results of these tests should be taken into account in the management of bleeding or invasive procedures in these patients., (Copyright © 2014 by the American Academy of Pediatrics.)

Molecular genetic analysis of families with hemophilia and other heritable bleeding disorders is a frequently requested laboratory investigation. In the United Kingdom, laboratories undertaking genetic testing must participate in a recognized external quality assessment scheme for formal accreditation. The UK National External Quality Assessment Scheme (UK NEQAS) for heritable bleeding disorders was established in its current format in 2003, and currently has 27 registered participants in the United Kingdom, the European Union (EU), and the non-EU countries. Two exercises per annum are circulated to participants comprising either whole blood or DNA isolated from cell lines, and laboratories are allowed 6 weeks to analyze the samples and generate a report. Reports are assessed by a panel comprising clinicians and scientists with expertise in this area. Samples to date have involved analysis of the F8 gene (10 exercises), the F9 gene (4 exercises), and the VWF gene (3 exercises) and have comprised a wide spectrum of mutations representing the routine workload encountered in the molecular genetics laboratory. The majority of laboratories in each exercise passed, but a small number did not and reasons for failing included clerical errors, genotyping inaccuracies, and a failure to correctly interpret data. Overall we have seen an improvement in quality of reports submitted for assessment, with a more concise format that will be of value to referring clinicians and counsellors. Informal feedback from participants has been very positive., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The new oral anticoagulants (NOACs) represent alternative antithrombotic agents for prophylaxis and therapy of thromboembolic diseases. They act either by inhibition of the clotting factor Xa or IIa (thrombin). As a consequence, they influence several coagulation assays (for example prothrombin time, activated partial thromboplastin time). Because of the short half-life of these new agents, these changes show great variations in the course of 24 hours. Furthermore, there are significant differences of laboratory results depending on the used reagents. We explain the influence of apixaban, rivaroxaban (factor Xa inhibitors) and dabigatran (thrombin inhibitor) on the most commonly used coagulation assays. Besides we show that this influence depends on the way of action of the drug as well as on the principle of the coagulation assay. Being aware of this relationships helps to interpret the results of coagulation assays under influence of NOACs correctly., (© Georg Thieme Verlag KG Stuttgart · New York.)

We describe three previously healthy children who developed acute extensive bruises about two weeks after a mild stomach bug. Coagulation tests revealed a shortened thromboplastin time (TT), long PT time, low level of coagulation factor II, and positive lupus anticoagulant among the antiphospholipid antibodies. In one patient the clinical symptoms disappeared during a one-week course of prednisolone, another one received a prothrombin complex preparation as substitution therapy. In the third patient the symptoms were milder and vanished without any specific treatment. The levels of coagulation factor increased in all patients and the lupus anticoagulant disappeared within a couple of months.