Active-control Randomized Trial Comparing 4-factor Prothrombin Complex Concentrate With Frozen Plasma in Cardiac Surgery

Defined as 'effective' if no additional hemostatic intervention, such as administration of any systemic hemostatic agents (including platelets, cryoprecipitate, fibrinogen concentrate, activated recombinant factor VII [rFVIIa], other coagulation factor products or a second dose of IMP) or any hemostatic interventions (including surgical re-opening for bleeding) is required from 60 minutes to 24 hours after initiation of the first dose of IMP.

Defined as 'positive' if no additional hemostatic intervention is required and hemoglobin levels decrease by <30% (after accounting for red cell transfusions) from 60 minutes to 24 hours after initiation of the first dose of IMP.

Yes or no refers to whether severe to massive bleeding was present.

The international normalized ratio (INR) is a standardized measure of prothrombin time (PT), ensuring consistency in results across different laboratories. The normal range for INR is around 0.8 to 1.2. Higher INR values indicate a slower clotting time and are associated with bleeding. Effective procoagulant therapy can reduce/normalize the INR.

INR reduction was considered successful if the magnitude of the reduction was >1.0 or the post-treatment level dropped below 1.5 (INR >1.5 indicates that one or more coagulation factor levels are below the 30% critical threshold)

The prothrombin time (PT) measures the time it takes for clotting to occur, primarily assessing the extrinsic pathway of the coagulation cascade. Normal PT values range from 9 to 13 seconds. Higher PT values indicate a prolonged clotting time, suggesting potential issues with clotting factors such as fibrinogen, factors V, VII, and X and prothrombin, and are associated with bleeding. Effective procoagulant therapy can reduce/normalize the PT.

Activated partial thromboplastin time (aPTT) is a standard laboratory test that measures how long it takes (in seconds) for clotting to occur (in the presence of an activator). It evaluates the intrinsic and common pathways of the coagulation cascade, assessing factors such as VIII, IX, XI, and XII, as well as fibrinogen. Prolonged aPTT may signify deficiencies in these clotting factors and is associated with bleeding. Effective procoagulant therapy can shorten/normalize the aPTT.

A rotational thromboelastometry (ROTEM; Werfen) device can be used at the bedside to rapidly assess the patient's coagulation status. Different viscoelastic tests can be performed to assess the dynamics of clot formation and lysis. Specifically, the EXTEM test is activated with tissue factor and evaluates the extrinsic coagulation pathway, with clotting time (CT) providing a measure (in seconds) of how quickly a clot starts forming. Prolonged EXTEM CT is associated with bleeding. Effective procoagulant therapy can reduce/normalize the EXTEM CT.

A rotational thromboelastometry (ROTEM; Werfen) device can be used at the bedside to rapidly assess the patient's coagulation status. Different viscoelastic tests can be performed to assess the dynamics of clot formation and lysis. Specifically, the EXTEM test is activated with tissue factor and evaluates the extrinsic coagulation pathway, with maximum clot firmness (MCF) providing a measure (in mm) of the strength of the clot. Reduced EXTEM MCF is associated with bleeding. Effective procoagulant therapy can increase/normalize the EXTEM MCF.

A rotational thromboelastometry (ROTEM; Werfen) device can be used at the bedside to rapidly assess the patient's coagulation status. Different viscoelastic tests can be performed to assess the dynamics of clot formation and lysis. Specifically, the FIBTEM test evaluates fibrin-based clotting - it is extrinsically activated with tissue factor and additionally incorporates an inhibitor to eliminate the contribution of platelets to clotting. Maximum clot firmness (MCF) in the FIBTEM test provides a measure (in mm) of the strength of the fibrin-based clot. Reduced FIBTEM MCF is associated with bleeding. Effective procoagulant therapy to restore fibrinogen can increase/normalize the FIBTEM MCF.

The Plateletworks device (Helena Laboratories) enables rapid bedside screening of platelet function. The system uses an impedance cell counter and Plateletworks reagent tubes to evaluate platelet function and monitor treatment effects. By comparing a baseline total platelet count against the platelet count measured in the presence of an agonist used to stimulate platelet aggregation (ADP, collagen, or arachidonic acid), the tests determine the percent aggregation or inhibition of functional platelets. Manufacturer reference ranges, determined by testing blood samples from healthy volunteers, are 86-100% for ADP, 70-100% for collagen, and 60-100% for arachidonic acid. Values within these ranges indicate 'normal (positive)' platelet aggregation, which is important for clotting; lower values may be considered 'abnormal (negative)' and reflective of platelet inhibition. The manufacturer advises each laboratory to establish their own reference ranges for their patient population.