Efficacy of a new pathogen-reduced cryoprecipitate stored 5 days after thawing to correct dilutional coagulopathy in vitro

Analyzing and modeling massive transfusion strategies and the role of fibrinogen-How much is the patient actually receiving?

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma, cardiac surgery, liver transplant, and childbirth. While emphasis on protocolization and ratio of blood product transfusion improves ability to treat hemorrhage rapidly, tools to facilitate understanding of the overall content of a specific transfusion strategy are lacking. Medical modeling can provide insights into where deficits in treatment could arise and key areas for clinical study. By using a transfusion model to gain insight into the aggregate content of massive transfusion protocols (MTPs), clinicians can optimize protocols and create opportunities for future studies of precision transfusion medicine in hemorrhage treatment.

METHODS

The transfusion model describes the individual round and aggregate content provided by four rounds of MTP, illustrating that the total content of blood elements and coagulation factor changes over time, independent of the patient's condition. The configurable model calculates the aggregate hematocrit, platelet concentration, percent volume plasma, total grams and concentration of citrate, percent volume anticoagulant and additive solution, and concentration of clotting factors: fibrinogen, factor XIII, factor VIII, and von Willebrand factor, provided by the MTP strategy.

RESULTS

Transfusion strategies based on a 1:1:1 or whole blood foundation provide between 13.7 and 17.2 L of blood products over four rounds. Content of strategies varies widely across all measurements based on base strategy and addition of concentrated sources of fibrinogen and other key clotting factors.

DISCUSSION

Differences observed between modeled transfusion strategies provide key insights into potential opportunities to provide patients with precision transfusion strategy.

What's in Your Transfusion? A Bedside Guide to Blood Products and Their Preparation

An understanding of the contents of blood products and how they are modified before transfusion will help any physician. This article will review five basic blood products and the five most common product modifications.

Preparation and Storage of Cryoprecipitate Derived from Amotosalen and UVA-Treated Apheresis Plasma and Assessment of In Vitro Quality Parameters

Cryoprecipitate is a plasma-derived blood product, enriched for fibrinogen, factor VIII, factor XIII, and von Willebrand factor. Due to infectious risk, the use of cryoprecipitate in Central Europe diminished over the last decades. However, after the introduction of various pathogen-reduction technologies for plasma, cryoprecipitate production in blood centers is a feasible alternative to pharmaceutical fibrinogen concentrate with a high safety profile. In our study, we evaluated the feasibility of the production of twenty-four cryoprecipitate units from pools of two units of apheresis plasma pathogen reduced using amotosalen and ultraviolet light A (UVA) (INTERCEPT^® Blood System). The aim was to assess the compliance of the pathogen-reduced cryoprecipitate with the European Directorate for the Quality of Medicines (EDQM) guidelines and the stability of coagulation factors after frozen (≤−25 °C) storage and five-day liquid storage at ambient temperature post-thawing. All pathogen-reduced cryoprecipitate units fulfilled the European requirements for fibrinogen, factor VIII and von Willebrand factor content post-preparation. After five days of liquid storage, content of these factors exceeded the minimum values in the European requirements and the content of other factors was sufficient. Our method of production of cryoprecipitate using pathogen-reduced apheresis plasma in a jumbo bag is feasible and efficient.

Effects of pathogen reduction technology and storage duration on the ability of cryoprecipitate to rescue induced coagulopathies in vitro

Background

Fibrinogen concentrates and cryoprecipitate are currently used for fibrinogen supplementation in bleeding patients with dysfibrinogenemia. Both products provide an abundant source of fibrinogen but take greater than 10 min to prepare for administration. Fibrinogen concentrates lack coagulation factors (i.e., factor VIII [FVIII], factor XIII [FXIII], von Willebrand factor [VWF]) important for robust hemostatic function. Cryoprecipitate products contain these factors but have short shelf lives (<6 h). Pathogen reduction (PR) of cryoprecipitate would provide a shelf‐stable immediately available adjunct containing factors important for rescuing hemostatic dysfunction.

Study Design and Methods

Hemostatic adjunct study products were psoralen‐treated PR‐cryoprecipitated fibrinogen complex (PR‐Cryo FC), cryoprecipitate (Cryo), and fibrinogen concentrates (FibCon). PR‐Cryo FC and Cryo were stored for 10 days at 20–24°C. Adjuncts were added to coagulopathies (dilutional, 3:7 whole blood [WB]:normal saline; or lytic, WB + 75 ng/ml tissue plasminogen activator), and hemostatic function was assessed by rotational thromboelastometry and thrombin generation.

Results

PR of cryoprecipitate did not reduce levels of FVIII, FXIII, or VWF. PR‐Cryo FC rescued dilutional coagulopathy similarly to Cryo, while generating significantly more thrombin than FibCon, which also rescued dilutional coagulopathy. Storage out to 10 days at 20–24°C did not diminish the hemostatic function of PR‐Cryo FC.

Discussion

PR‐Cryo FC provides similar and/or improved hemostatic rescue compared to FibCon in dilutional coagulopathies, and this rescue ability is stable over 10 days of storage. In hemorrhaging patients, where every minute delay is associated with a 5% increase in mortality, the immediate availability of PR‐Cryo FC has the potential to improve outcomes.

Global sources of cryoprecipitate demonstrate variability in coagulant factor levels and functional hemostasis

Cryoprecipitate (cryo) is a plasma-derived blood product utilized during trauma resuscitation, surgery, and other major bleeding. Although local quality control metrics exist, inherent donor variability, and processing may confer differences in hemostatic effect between sources. The purposes of this study were to quantify procoagulant content in three global sources of cryo and evaluate their functional hemostatic effect. In this Institutional Review Board exempt study, 24 units of group A cryo from three different sources, American Red Cross single donor and pooled donor, Australian Red Cross single donor, Southwestern United States single donor, and Southwest pooled donor, were evaluated. Procoagulant factors were quantified from each source using ELISA and automated clot-based assays. Functional hemostasis was evaluated using rotational Thromboelastometry (ROTEM). Microparticles isolated from cryo units were enumerated and evaluated for cellular origin by flow cytometry, as well as their capacity to support thrombin generation. Southwestern United States single donor units demonstrated highest levels of fibrinogen, fibronectin, factor VIII, and von Willebrand factor in the selected units. In the coagulopathy model, successive doses from all cryo units were significantly correlated to decreasing coagulation time (P = 0.0100), and increasing maximum clot firmness (P = 0.0002) and alpha angle (P = 0.0009). Southwest pooled donor demonstrated significantly shorter coagulation time at all three doses (P = 0.02) than other sources. Microparticles support prothrombinase activity and thrombin generation. In this study of global cryo sources, procoagulant activity and in-vitro clot formation varied by source. This could be explained by variance in production and storage protocols. Further study is warranted to assess functional variance in cryo to optimize and standardize the use of cryo products.

Pediatric Fibrinogen PART I-Pitfalls in Fibrinogen Evaluation and Use of Fibrinogen Replacement Products in Children

Fibrinogen is a key coagulation protein, playing a critical role in hemostasis. It is the first factor to decrease to critical levels during bleeding. Hypofibrinogenemia is an important risk factor for bleeding in clinical settings, including pediatric surgery. Yet, the optimal measurement of fibrinogen levels is subject to debate, as is the critical threshold for intervention. Fibrinogen replacement may be provided by cryoprecipitate and fibrinogen concentrate. Whilst both products contain fibrinogen, they are not equivalent, each has its own advantages and disadvantages, especially for pediatric use. Unfortunately, medical literature to support fibrinogen replacement in children is limited. In this article we review the current diagnostic tools to measure fibrinogen, with respect to their use in the pediatric critical care setting. Secondly, we evaluate the different fibrinogen replacement therapies, focusing on cryoprecipitate and fibrinogen concentrate and examine their individual product characteristics, associated risks and benefits, different dosing strategies and specific pitfalls for use in children. We summarize by highlighting current knowledge gaps and areas for future research.

The effect of pathogen inactivation on cryoprecipitate: a functional and quantitative evaluation

BACKGROUND

As a pooled donor blood product, cryoprecipitate (cryo) carries risks of pathogen transmission. Pathogen inactivation (PI) improves the safety of cryoprecipitate, but its effects on haemostatic properties remain unclear. This study investigated protein expression in samples of pathogen inactivated cryoprecipitate (PI-cryo) using non-targeted quantitative proteomics and in vitro haemostatic capacity of PI-cryo.

MATERIALS AND METHODS

Whole blood (WB)- and apheresis (APH)-derived plasma was subject to PI with INTERCEPT^® Blood System (Cerus Corporation, Concord, CA, USA) and cryo was prepared from treated plasma. Protein levels in PI-cryo and paired controls were quantified using liquid chromatography-tandem mass spectrometry. Functional haemostatic properties of PI-cryo were assessed using a microparticle (MP) prothrombinase assay, thrombin generation assay, and an in vitro coagulopathy model subjected to thromboelastometry.

RESULTS

Over 300 proteins were quantified across paired PI-cryo and controls. PI did not alter the expression of coagulation factors, but levels of platelet-derived proteins and platelet-derived MPs were markedly lower in the WB PI-cryo group. Compared to controls, WB (but not APH) cryo samples demonstrated significantly lower MP prothrombinase activity, prolonged clotting time, and lower clot firmness on thromboelastometry after PI. However, PI did not affect overall thrombin generation variables in either group.

DISCUSSION

Data from this study suggest that PI via INTERCEPT^® Blood System does not significantly impact the coagulation factor content or function of cryo but reduces the higher MP content in WB-derived cryo. PI-cryo products may confer benefits in reducing pathogen transmission without affecting haemostatic function, but further in vivo assessment is warranted.

Which is the preferred blood product for fibrinogen replacement in the bleeding patient with acquired hypofibrinogenemia-cryoprecipitate or fibrinogen concentrate?

The importance of the targeted treatment of acquired hypofibrinogenemia during hemorrhage with a concentrated fibrinogen product (either cryoprecipitate or fibrinogen concentrate) cannot be underestimated. Fibrinogen concentrate is a pathogen inactivated, pooled product that offers a highly purified single factor concentrate. Cryoprecipitate is a pooled product that comes with a spectrum of other coagulation factors which may further enhance (additional procoagulant effect) or even disturb (prothrombotic risk) hemostasis. The pros and cons of each product are discussed.