Mining of mortality-related findings in rare bleeding disorders: A retrospective study from two centers

Background Rare bleeding disorders include inherited coagulation disorders except for von Willebrand disease and hemophilia A and B. These disorders affect both men and women worldwide and mainly have an autosomal recessive pattern of inheritance. Given the paucity of cases of rare bleeding disorders, there are limited data regarding some topics among bleeding disorders. Methods This retrospective study from 2005�2019 collected demographic data and the causes of death among cases with rare bleeding disorders from 2 provinces of Iran. Results Overall, 5 deaths were reported, including 3 cases with factor V deficiency, a case with factor XIII deficiency, and a case with combined factor V and factor VIII deficiencies. The main causes of death were bleeding in the central nervous system (2 cases; 1 with factor V deficiency and 1 with combined factor XIII deficiency). Post-partum hemorrhage was the cause of death in a woman with factor V deficiency while anaphylaxis shock was the cause of death in the case with combined factor V and factor VIII deficiencies. A woman with factor V deficiency died from an internal bleeding episode. Conclusion Gathering data on the causes of death in rare bleeding disorders through worldwide registries can be helpful for the management of this rare group of bleeding disorders. © 2020 Korean Society of Hematology. All rights reserved

Current methods of measuring platelet activity:pros and cons

Platelets play a pivotal role in controlling hemorrhaging from vessels of the human body. The impairment of platelets may lead to the development of bleeding manifestations. Unraveling the precise defects of platelets by means of suitable laboratory methods paves the way for the effective control and management of platelet disorders. Choosing the most appropriate approach for the detection of platelet disorders may be difficult for a researcher or clinical internist when faced with ordering a platelet-function test. The aim of the current study was to provide a user-friendly overview of the advantages and disadvantages of the available detection systems. To reach this goal, 11 commonly used methods of studying platelet activity were evaluated and compared in detail. A literature search, with no time or language limitations, was conducted in Google Scholar and Medline. All publications published before June 2019 were analyzed. The following laboratory methods were compared: number and size of platelets, bleeding time, clot retraction time, platelet function assay 100 & 200, Rapid platelet function assay, flow cytometry, light transmission aggregometry, multiple electrode aggregometry, 96-well plate aggregometry, cone and plate(let) analyzer (Impact-R), and Plateletworks (single platelet counting system). This article provides the reader with a rapid comparison of the different systems used to study platelets activities

Pharmacokinetic–Pharmacodynamic Modelling in Hemophilia A:Relating Thrombin and Plasmin Generation to Factor VIII Activity After Administration of a VWF/FVIII Concentrate

Background: Hemophilia A patients are treated with factor (F) VIII prophylactically to prevent bleeding. In general, dosage and frequency are based on pharmacokinetic measurements. Ideally, an alternative dose adjustment can be based on the hemostatic potential, measured with a thrombin generation assay (TGA), like the Nijmegen hemostasis assay. Objective: The objective of this study was to investigate the predicted performance of a previously developed pharmacokinetic–pharmacodynamic model for FVIII replacement therapy, relating FVIII dose and FVIII activity levels with thrombin and plasmin generation parameters. Methods: Pharmacokinetic and pharmacodynamic measurements were obtained from 29 severe hemophilia A patients treated with pdVWF/FVIII concentrate (Haemate P®). The predictive performance of the previously developed pharmacokinetic–pharmacodynamic model was evaluated using nonlinear mixed-effects modeling (NONMEM). When predictions of FVIII activity or TGA parameters were inadequate [median prediction error (MPE) &gt; 20%], a new model was developed. Results: The original pharmacokinetic model underestimated clearance and was refined based on a two-compartment model. The pharmacodynamic model displays no bias in the observed normalized thrombin peak height and normalized thrombin potential (MPE of 6.83% and 7.46%). After re-estimating pharmacodynamic parameters, EC50 and Emax values were relatively comparable between the original model and this group. Prediction of normalized plasmin peak height was inaccurate (MPE 58.9%). Conclusion: Our predictive performance displayed adequate thrombin pharmacodynamic predictions of the original model, but a new pharmacokinetic model was required. The pharmacodynamic model is not factor specific and applicable to multiple factor concentrates. A prospective study is needed to validate the impact of the FVIII dosing pharmacodynamic model on bleeding reduction in patients.</p