Human Fibrinogen Concentrate (RiaSTAP and Fibryga)

Number: 0792

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses human fibrinogen concentrate (RiaSTAP and Fibryga) for commercial medical plans. For Medicare criteria, see Medicare Part B Criteria.

Note: Requires Precertification:

Precertification of human fibrinogen concentrate (Fibryga, RiaSTAP) is required of all Aetna participating providers and members in applicable plan designs.  For precertification, call Aetna's Special Case Precert Unit at (855) 888-9046.

Fibryga

1. Criteria for Initial Approval

   Congenital Fibrinogen Deficiency

   Aetna considers human fibrinogen concentrate (Fibryga) medically necessary for the treatment of acute bleeding episodes in members with a diagnosis of congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia.

   Aetna considers all other indications as experimental and investigational (for additional information, see Experimental and Investigational and Background sections).

2. Continuation of Therapy

   Aetna considers continuation of human fibrinogen concentrate (Fibryga) therapy medically necessary for all members (including new members) requesting reauthorization and who meet all initial medical necessity selection criteria.

RiaSTAP

1. Criteria for Initial Approval

   Aetna considers human fibrinogen concentrate (RiaSTAP) medically necessary for any of the following indications:

   Congenital Fibrinogen Deficiency

   1. For treatment of acute bleeding episodes in members with a diagnosis of congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia
   2. For perioperative management of bleeding in members with a diagnosis of afibrinogenemia
   3. For prophylaxis to reduce the frequency of bleeding episodes in members with afibrinogenemia (with justification from the medical records).

   Aetna considers all other indications as experimental and investigational (for additional information, see Experimental and Investigational and Background sections).

2. Continuation of Therapy

   1. Prophylaxis to reduce the frequency of bleeding episodes in afibrinogenemia

      Aetna considers continuation of human fibrinogen concentrate (RiaSTAP) therapy medically necessary for members requesting reauthorization for prophylaxis to reduce the frequency of bleeding episodes in afibrinogenemia when the member is experiencing benefit from therapy (e.g., reduced frequency of bleeding episodes).

   2. All other indications:

      Aetna considers continuation of human fibrinogen concentrate (RiaSTAP) therapy medically necessary for all members (including new members) requesting reauthorization and who meet all initial medical necessity selection criteria.

Dosage and Administration

When the fibrinogen level is known:

Fibryga:         Target fibrinogen level (mg/dl) – measured fibrinogen level (mg/dL)
                                    1.8 (mg/dL per mg/kg body weight)  

RiaSTAP:      Target fibrinogen level (mg/dl) – measured fibrinogen level (mg/dL)
                                    1.7 (mg/dL per mg/kg body weight)

When the fibrinogen level is not known: 70mg/kg body weight for RiaSTAP and Fibryga.

Source: Fibryga (Octapharma, 2020); RiaSTAP (CSL Behring, 2021)

Experimental and Investigational

Aetna considers human fibrinogen concentrate experimental and investigational for the treatment of the following indications (not an all-inclusive list) because its effectiveness for these indications has not been established.

• Acquired hypofibrinogenemia (acquired fibrinogen deficiency)
• Bleeding associated with aortic reconstruction and deep hypothermic circulatory arrest
• Dysfibrinogenemia
• Intra-operative use to prevent bleeding in neonatal and infant cardiac surgery
• Obstetric hemorrhage including post-partum hemorrhage in persons without congenital fibrinogen deficiency
• Trauma-associated hemorrhage in persons without congenital fibrinogen deficiency.

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Other CPT codes related to the CPB:
33120	Excision of intracardiac tumor, resection with cardiopulmonary bypass
33305	Repair of cardiac wound; with cardiopulmonary bypass
33315	Cardiotomy, exploratory (includes removal of foreign body, atrial or ventricular thrombus); with cardiopulmonary bypass
33322	Suture repair of aorta or great vessels; with cardiopulmonary bypass
33335	Insertion of graft, aorta or great vessels; with cardiopulmonary bypass
33390 - 33391	Valvuloplasty, aortic valve, open, with cardiopulmonary bypass
33405	Replacement, aortic valve, with cardiopulmonary bypass; with prosthetic valve other than homograft or stentless valve
33406	Replacement, aortic valve, with cardiopulmonary bypass; with allograft valve (freehand)
33410	Replacement, aortic valve, with cardiopulmonary bypass; with stentless tissue valve
33422	Valvotomy, mitral valve; open heart, with cardiopulmonary bypass
33425	Valvuloplasty, mitral valve, with cardiopulmonary bypass
33426	Valvuloplasty, mitral valve, with cardiopulmonary bypass; with prosthetic ring
33427	Valvuloplasty, mitral valve, with cardiopulmonary bypass; radical reconstruction, with or without ring
33430	Replacement, mitral valve, with cardiopulmonary bypass
33460	Valvectomy, tricuspid valve, with cardiopulmonary bypass
33465	Replacement, tricuspid valve, with cardiopulmonary bypass
33474	Valvotomy, pulmonary valve, open heart; with cardiopulmonary bypass
33496	Repair of non-structural prosthetic valve dysfunction with cardiopulmonary bypass (separate procedure)
33500	Repair of coronary arteriovenous or arteriocardiac chamber fistula; with cardiopulmonary bypass
33504	Repair of anomalous coronary artery from pulmonary artery origin; by graft, with cardiopulmonary bypass
33641	Repair atrial septal defect, secundum, with cardiopulmonary bypass, with or without patch
33702	Repair sinus of Valsalva fistula, with cardiopulmonary bypass
33710	Repair sinus of Valsalva fistula, with cardiopulmonary bypass; with repair of ventricular septal defect
33720	Repair sinus of Valsalva aneurysm, with cardiopulmonary bypass
33736	Atrial septectomy or septostomy; open heart with cardiopulmonary bypass
33814	Obliteration of aortopulmonary septal defect; with cardiopulmonary bypass
33853	Repair of hypoplastic or interrupted aortic arch using autogenous or prosthetic material; with cardiopulmonary bypass
33858	Ascending aorta graft, with cardiopulmonary bypass, includes valve suspension, when performed; for aortic dissection
33859	for aortic disease other than dissection (eg, aneurysm)
33864	Ascending aorta graft, with cardiopulmonary bypass with valve suspension, with coronary reconstruction and valve sparing aortic root remodeling (e.g., David Procedure, Yacoub Procedure
33875	Descending thoracic aorta graft, with or without bypass
33877	Repair of thoracoabdominal aortic aneurysm with graft, with or without cardiopulmonary bypass
33910	Pulmonary artery embolectomy; with cardiopulmonary bypass
33916	Pulmonary endarterectomy, with or without embolectomy, with cardiopulmonary bypass
33922	Transection of pulmonary artery with cardiopulmonary bypass
33926	Repair of pulmonary artery arborization anomalies by unifocalization; with cardiopulmonary bypass
85384	Fibrinogen; activity
85385	antigen
96374	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); intravenous push, single or initial substance/drug
96375	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); each additional sequential intravenous push of a new substance/drug (List separately in addition to code for primary procedure)
96376	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); each additional sequential intravenous push of the same substance/drug provided in a facility (List separately in addition to code for primary procedure)
96379	Unlisted therapeutic; prophylactic, or diagnostic intravenous or intra-arterial injection or infusion
HCPCS codes covered if selection criteria are met:
J7177	Injection, human fibrinogen concentrate (fibryga), 1 mg
J7178	Injection, human fibrinogen concentrate, not otherwise specified, 1 mg [RiaSTAP]
ICD-10 codes covered if selection criteria are met:
D68.2	Hereditary deficiency of other clotting factors [congenital fibrinogen deficiency]
D68.8	Other specified coagulation defects
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
D65	Disseminated intravascular coagulation [defibrination syndrome]
D78.01 - D78.02 D78.21 - D78.22 E36.01 - E36.02 G97.31 - G97.32 G97.51 - G97.52 G97.61 - G97.64H59.111 - H59.129 H59.311 - H59.312	Hemorrhage and hematoma complicating a procedure
O72.0 - O72.3	Postpartum hemorrhage
O86.0, O90.2	Other complications of obstetrical surgical wounds

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Background

U.S. Food and Drug Administration (FDA)-Approved Indications for Fibryga

• Fibryga is indicated for the treatment of acute bleeding episodes in adults and children with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia.

Fibryga is not indicated for dysfibrinogenemia.

U.S. Food and Drug Administration (FDA)-Approved Indications for RiaSTAP

• RiaSTAP is indicated for the treatment of acute bleeding episodes in pediatric and adult patients with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia.

Limitation of use: RiaSTAP is not indicated for dysfibrinogemia.

Compendial Uses for RiaSTAP

• Perioperative management of bleeding in afibrinogenemia
• Prophylaxis to reduce the frequency of bleeding episodes in afibrinogenemia

Fibrinogen, also known as Factor I, is synthesized in the liver and circulates in the blood with a normal plasma concentration of 250 to 400 mg/dL (2.5 to 4.0 g/L).  It plays an important role in clotting of the blood.  Diminished concentrations of fibrinogen limit the body's ability to form a clot.  Congenital fibrinogen deficiency (CFD) is a rare, potentially life-threatening bleeding disorder.  Individuals with CFD are unable to make sufficient amounts of fibrinogen.  There are 2 types of hereditary fibrinogen disorders:

1. type I deficiencies (quantitative defects) such as afibrinogenemia and hypofibrinogenemia – with low or unmeasurable levels of immunoreactive protein; and
2. type II deficiencies (qualitative defects) such as dysfibrinogenemia and hypodysfibrinogenemia – with normal or altered antigen levels associated with reduced coagulant activity. 

While dysfibrinogenemias are in most cases autosomal dominant disorders, type I deficiencies are generally inherited as autosomal recessive traits.  Patients affected by congenital afibrinogenemia or severe hypofibrinogenemia may experience bleeding manifestations varying from mild to severe (Asselta et al, 2006).

Congenital fibrinogen deficiency affects an estimated 1 person per 1,000,000, with an estimated prevalence of 150 to 300 people in the United States.  It is usually diagnosed at birth when newborns bleed from their umbilical cord site.  al-Mondhiry and Ehmann (1994) noted that diagnosis of congenital afibrinogenemia is usually established by demonstrating trace or absent immunoreactive fibrinogen in the plasma.  Patients with hypofibrinogenemia are usually asymptomatic, unless exposed to trauma.  Furthermore, Berube (2009) stated that disorders involving fibrinogen are rare but should be considered in any patient with a history of hemorrhage or thrombosis in whom most of the common causes have been ruled out.  Blood coagulation tests such as prothrombin time (PT) that is often reported as the International Normalized Ratio (INR), activated partial thromboplastin time (APTT), and thrombin clotting time (TCT) or thrombin time (TT) all require the production of a fibrin clot as an end point, and will be abnormally prolonged in patients with hypofibrinogenemia or afibrinogenemia.  Abnormal laboratory results in patients with afibrinogenemia will correct completely following administration of normal plasma or purified fibrinogen.  Accordingly, these tests are sensitive for the presence of a fibrinogen disorder, but lack specificity.

Verhovsek and colleagues (2008) provided examples of methods and findings for commonly used laboratory tests for afibrinogenemia and hypofibrinogenemia:

Table: Methods and findings for afibrinogenemia and hypofibrinogenemia

Methods and Findings	Afibrinogenemia	Hypofibrinogenemia
Clinical Problem	Trauma-related intra-cranial hemorrhage at age 40.  Subsequent trauma-related and surgery-related bleeding	Recurrent pregnancy loss from placental abruptions
PT (normal: 11 to 14 sec)	No clot detected	14.2
INR (normal: 0.8 to 1.2)	No clot detected	1.2
APTT (normal: 22 to 35 sec)	No clot detected	32
TCT or TT (normal: 20 - 30 sec)	No clot detected	46
Reptilase time (normal: 15 - 27 sec)	> 60	33
Clottable fibrinogen (normal: 160 - 420 mg/dL)	< 20	60
Fibrinogen antigen (normal: 160 - 420 mg/dL)	< 10	60
Ratio of fibrinogen antigen to clottable fibrinogen	–	1.0

Individuals with CFD are advised to curtail physical activities because of risk of bleeding from minor trauma.  If bleeding occurs in the brain or other organs and is left untreated, it may lead to blood loss, organ damage and death.  The standard approach for replacement of fibrinogen in patients with CFD is cryoprecipitate; but more recently, a pasteurized human fibrinogen concentrate has become available.

In an open, multi-center, non-controlled, retrospective study, Kreuz and co-workers (2005) examined the effectiveness and tolerability of a pasteurized human fibrinogen concentrate in patients with CFD.  Hemostatic efficacy was assessed by laboratory investigation as well as clinical observation.  A total of 12 patients (afibrinogenemia, n = 8; hypofibrinogenemia, n = 3; dysfibrinogenemia combined with hypofibrinogenemia, n = 1) were included in the study.  Fibrinogen substitution was indicated for one of the following reasons:

1. to stop an ongoing bleed;
2. as prophylaxis before surgery; or
3. for routine prophylaxis to prevent spontaneous bleeding. 

A total of 151 fibrinogen infusions were recorded.  The median single dosage was 63.5 mg/kg body weight of the drug for bleeding events or surgery and 76.9 mg/kg for prophylaxis.  The median total dose per event for bleeding events or surgery was 105.6 mg/kg.  Fibrinogen was administered in 26 bleeding episodes; 11 surgical operations; and 89 prophylactic infusions, of which 86 were received by 1 patient.  The median response (n = 8) was 1.5 mg/dL per substituted mg of fibrinogen per kg body weight (0.8 to 2.3).  The median in vivo recovery (n = 8) was 59.8 % (32.5 to 93.9).  Clinical efficacy was very good in all events with the exception of one surgical procedure, where it was moderate.  No intercurrent bleeding occurred during prophylaxis.  All but 1 infusion was well-tolerated; the patient, who was administered 86 prophylactic infusions, experienced an anaphylactic reaction after the 56th infusion.  In addition, one patient developed deep vein thrombosis and nonfatal pulmonary embolism with treatment for osteosynthesis after collum femoris fracture.  Fibrinogen substitution could not be excluded as a contributing factor in this high-risk patient.  The authors concluded that substitution with pasteurized human fibrinogen concentrate in patients with CFD is efficient and generally well tolerated.

A review by de Moerloose and colleagues (2013) stated that "Depending on the country of residence, patients receive fresh frozen plasma (FFP), cryoprecipitate, or fibrinogen concentrates.  Fibrinogen concentrate preparation includes safety steps for inactivation/removal of viruses, so concentrates are safer than cryoprecipitate or FFP". 

Bevan (2009) stated that congenital abnormalities of fibrinogen are rare disorders classified as quantitative (afibrinogenemia and hypofibrinogenemia) or qualitative types (dysfibrinogenemia and hypodysfibrinogenemia).  Fibrinogen is essential to hemostasis as the substrate for fibrin clot formation and also acts in primary hemostasis as a key ligand in platelet aggregation.  Quantitative deficiency of fibrinogen can result in severe bleeding, or arterial and venous thromboembolism, and poor wound healing.  Dysfibrinogenemia is characterized by functional abnormalities of fibrinogen, which may be asymptomatic (in 50 % of cases), or cause bleeding (25 %) or thrombosis (25 %).  Replacement of the deficient or abnormal fibrinogen with frozen plasma, cryoprecipitate, or fibrinogen concentrate has been found to be effective in practice in treating hemostatic complications of these disorders.  Although cryoprecipitate is the most commonly used replacement material, pathogen-reduced fibrinogen concentrates have several advantages, most importantly a lower potential risk of viral transmission and standardized fibrinogen content allowing accurate dosing.  They also avoid transfusing unwanted clotting factors, platelet micro-particles and immunoglobulins, and can be administered rapidly without thawing.  The use of fibrinogen concentrate to treat congenital fibrinogen disorders is strongly supported in principle and increasingly by practical experience and evidence. 

Levy et al (2012) noted that there currently is a lack of awareness among physicians regarding the significance of fibrinogen during acute bleeding and, at many medical centers, fibrinogen is not monitored routinely during treatment.  These investigators reviewed current studies that demonstrate the importance of considering fibrinogen replacement during the treatment of acquired bleeding across clinical settings.  If depleted, the supplementation of fibrinogen is key for the rescue and maintenance of hemostatic function; however, the threshold at which such intervention should be triggered is currently poorly defined.  Although traditionally performed via administration of fresh frozen plasma or cryoprecipitate, the use of lyophilized fibrinogen (concentrate) is becoming more prevalent in some countries.  Recent reports relating to the efficacy of fibrinogen concentrate suggest that it is a viable alternative to traditional hemostatic approaches, which should be considered. 

Levy et al (2014) stated that fibrinogen supplementation can be achieved using plasma or cryoprecipitate; however, there are a number of safety concerns associated with these allogeneic blood products and there is a lack of high-quality evidence to support their use.  Additionally, there is sometimes a long delay associated with the preparation of frozen products for infusion.  Fibrinogen concentrate provides a promising alternative to allogeneic blood products and has a number of advantages: it allows a standardized dose of fibrinogen to be rapidly administered in a small volume, has a very good safety profile, and is virally inactivated as standard.  Administration of fibrinogen concentrate, often guided by point-of-care viscoelastic testing to allow individualized dosing, has been successfully used as hemostatic therapy in a range of clinical settings, including cardiovascular surgery, post-partum hemorrhage, and trauma.  Results showed that fibrinogen concentrate is associated with a reduction or even total avoidance of allogeneic blood product transfusion.  Fibrinogen concentrate represents an important option for the treatment of coagulopathic bleeding; further studies are needed to determine precise dosing strategies and thresholds for fibrinogen supplementation. 

Elliott and Aledort (2013) stated that fibrinogen plays a key role in the coagulation process, and therefore maintaining adequate quantities of fibrinogen is an essential step in achieving satisfactory hemostasis in patients with acquired hypofibrinogenemia.  Potential options for treating acquired hypofibrinogenemia in patients with uncontrolled bleeding include the use of cryoprecipitate or fibrinogen replacement therapy.  These investigators provided a brief overview of the hemostatic process and the methods for assessing coagulopathy and discussed the safety and effectiveness of cryoprecipitate and fibrinogen concentrate in restoring fibrinogen levels, achieving hemostasis and reducing transfusion requirements in different patient populations requiring rapid hemostasis.  Other issues relevant to the clinical use of these agents in restoring hemostasis, including variations in product composition, preparation time and cost, were also examined. The authors also noted that “Although it has been shown that fibrinogen concentrate offers a more rigorous viral inactivation process and has the potential for more rapid and predictable dosing than cryoprecipitate, there remains a clear need for prospective, randomized studies to establish the precise role of fibrinogen concentrate in achieving hemostasis, reducing transfusion requirements, and, more importantly, improving hard clinical outcomes such as morbidity and mortality in patients with acquired coagulopathies.  Moreover, these studies need to further elucidate the threshold for fibrinogen concentrate treatment and the most appropriate dosages in different patient populations requiring rapid hemostasis.  Finally, these prospective, randomized studies need to confirm the optimal timing of intervention with fibrinogen concentrate”.

Anu UpToDate review on "Disorders of fibrinogen" (Casini and Bérubé, 2023) noted "For congenital fibrinogen disorders, we suggest a fibrinogen concentrate rather than Cryoprecipitate or a plasma product. This is a US Food and Drug Administration (FDA)-approved indication for fibrinogen concentrates. Cryoprecipitate may be used if a fibrinogen concentrate is not available, and plasma may be used if Cryoprecipitate is not available. The rationale for preferring a fibrinogen concentrate includes the small volume, ease of administration, lower risk of transfusion reactions and volume overload, and likely lower risk of thromboembolic complications."

Fenger-Eriksen and colleagues (2008) noted that patients experiencing massive hemorrhage are at high risk of developing coagulopathy through loss, consumption, and dilution of coagulation factors and platelets.  It has been reported that plasma fibrinogen concentrations may reach a critical low level relatively early during bleeding, calling for replacement fibrinogen therapy.  These researchers audited the effects of fibrinogen concentrate therapy on laboratory and clinical outcome in patients with massive hemorrhage.  They identified 43 patients over the previous 2 years to whom a fibrinogen concentrate had been administered as treatment for hypofibrinogenemia during serious hemorrhage.  Platelet count, plasma fibrinogen, activated partial thromboplastin time (APTT), prothrombin time (PT), D-dimer, and volume of blood lost were obtained from medical and laboratory records.  Numbers of units of red blood cells (RBC), fresh frozen plasma (FFP), and pooled platelet concentrates were recorded before and after fibrinogen substitution.  A significant increase in plasma fibrinogen concentration was observed after fibrinogen concentrate therapy.  Platelet counts and fibrin D-dimer values remained unchanged, whereas the APTT and PT improved significantly.  Requirements for RBC, FFP, and platelets were significantly reduced; blood loss decreased significantly.  The authors concluded that fibrinogen substitution therapy with a fibrinogen concentrate generally improved global laboratory coagulation results; and as supplementary intervention, appeared to reduce the requirements for RBC, FFP, and platelet substitution in this patient cohort.

On January 16, 2009, the Food and Drug Administration (FDA) licensed RiaSTAP (human fibrinogen concentrate) for the treatment of acute bleeding in patients with CFD.  RiaSTAP is a purified fibrinogen concentrate made from the plasma of healthy human donors that undergoes virus inactivation and removal for safety assurance.  It was developed under the FDA’s accelerated approval regulations for orphan drugs.  There have been more than 1,000,000 units sold worldwide (outside the United States, RiaSTAP is marketed under the trade name of Haemocomplettan).  RiaSTAP is indicated for the treatment of acute bleeding episodes in patients with CFD including afibrinogenemia and hypofibrinogenemia; it is not indicated for dysfibrinogenemia.

The licensing of RiaSTAP was based on a phase II, prospective, open-label, safety and pharmacokinetic study using maximum clot firmness (MCF) as a surrogate endpoint for hemostatic efficacy.  A total of 15 patients with afibrinogenemia achieved the target level of fibrinogen expected to prevent bleeding after they received 70 mg/kg body weight of the drug.  In addition, plasma from 14 of the 15 patients showed a highly significant (p < 0.0001) mean improvement in MCF from baseline to 1 hour post-infusion following RiaSTAP treatment.  The most serious adverse reactions that have been reported in clinical studies or through post-marketing surveillance following RiaSTAP treatment are allergic-anaphylactic reactions and thromboembolic episodes, including myocardial infarction, pulmonary embolism, deep vein thrombosis and arterial thrombosis.  The most common adverse reactions that have been reported after RiaSTAP therapy are allergic reactions and generalized reactions such as chills, fever, headache, as well as nausea and vomiting.

In addition to the treatment of CFD, human fibrinogen concentrate has also been employed in the management of other hypofibrinogenemic conditions such as acquired hypofibrinogenemia and post-operative hemorhage.  Clinical data for the use of human fibrinogen concentrate in acquired hypofibrinogenemic states are scarce.  Weinkove and Rangarajan (2008) evaluated the safety and effectiveness of Haemocomplettan in patients with acquired hypofibrinogenemia.  Demographical and pre-treatment clinical data of patients treated with Haemocomplettan were retrospectively reviewed.  Pre- and post-treatment fibrinogen levels, transfusion requirements, outcomes and adverse reactions were recorded.  A total of 30 adult patients who received Haemocomplettan for acquired hypofibrinogenemia (plasma fibrinogen concentration less than 1.5 g/L) were included in the study.  Causes of hypofibrinogenemia included placental abruption, disseminated intravascular coagulation as a result of massive blood loss and transfusion, liver failure and cardiac surgery.  Following a median dose of 4 g Haemocomplettan, median Clauss fibrinogen level rose from 0.65 to 2.01 g/L, with a median fibrinogen increment of 0.25 g/L per 1 g fibrinogen concentrate administered.  It was reporetd that 46 % of patients stopped bleeding with blood components and Haemocomplettan alone, and a further 29 % stopped bleeding with surgical or endoscopic intervention.  Inpatient mortality was 40 %; no venous thromboses were observed.  A total of 4 patients with massive perioperative hemorrhage and hypotension (including 3 post-cardiothoracic surgery) had arterial ischemic events, however, none of which was attributable to over-replacement of fibrinogen.  The cost of Haemocomplettan was comparable with that of cryo-precipitate.  The authors concluded that purified human fibrinogen concentrate appears effective in the management of acquired hypofibrinogenemia.

Bleeding diathesis after aortic valve operation and ascending aorta replacement (AV-AA) is usually managed with FFP and platelet concentrates.  In a pilot study, Rahe-Meyer et al (2009) compared hemostatic effects of conventional transfusion management and FIBTEM (thromboelastometry test)-guided fibrinogen concentrate administration.  A blood-product transfusion algorithm was developed with retrospective data from 42 elective patients (group A).  Two units of platelet concentrate were transfused after cardiopulmonary bypass, followed by 4 units of FFP if bleeding persisted, if platelet count was less than or equal to 100 x 10(3) microl(-1) when removing the aortic clamp, and vice versa if platelet count was greater than 100 x 10(3) microl(-1).  The trigger for each therapy step was greater than or equal to 60 g blood absorbed from the mediastinal wound area by dry swabs in 5 mins.  Assignment to two prospective groups was neither randomized nor blinded; group B (n = 5) was treated according to the algorithm, group C (n = 10) received Haemocomplettan/RiaSTAP before the algorithm-based therapy.  A mean of 5.7 (0.7) g fibrinogen concentrate decreased blood loss to below the transfusion trigger level in all group C patients.  Group C had reduced transfusion [mean of 0.7 (range of 0 to 4) units versus 8.5 (5.3) units in group A and 8.2 (2.3) units in group B] and reduced post-operative bleeding [366 (199) ml versus 793 (560) ml in group A and 716 (219) ml in group B].  The authors concluded that in this pilot study, FIBTEM-guided fibrinogen concentrate administration was associated with reduced transfusion requirements and 24-hr post-operative bleeding in patients undergoing AV-AA.

In a prospective randomised pilot study, Karlsson et al (2009) examined if prophylactic infusion of fibrinogen concentrate may reduce post-operative bleeding.  A total of 20 elective coronary artery bypass graft (CABG) patients with pre-operative plasma fibrinogen levels of less than 3.8 g/L were included in this study.  Patients were randomized to receive an infusion of 2 g fibrinogen concentrate (FIB group) or no infusion before surgery (control group).  Primary endpoint was safety with clinical adverse events and graft occlusion assessed by multi-slice computed tomography.  Pre-defined secondary endpoints were post-operative blood loss, blood transfusions, hemoglobin levels 24 hrs after surgery, and global hemostasis assessed with thromboelastometry, 2 and 24 hrs after surgery.  Infusion of 2 g fibrinogen concentrate increased plasma levels of fibrinogen by 0.6 +/- 0.2 g/L.  There were no clinically detectable adverse events of fibrinogen infusion.  Computed tomography revealed 1 sub-clinical vein graft occlusion in the FIB group.  Fibrinogen concentrate infusion reduced post-operative blood loss by 32 % (565 +/- 150 versus 830 +/- 268 ml/12 hrs, p = 0.010).  Hemoglobin concentration was significantly higher 24 hrs after surgery in the FIB group (110 +/- 12 versus 98 +/- 8 g/L, p = 0.018).  Prophylactic fibrinogen concentrate infusion did not influence global post-operative hemostasis as assessed by thromboelastometry.  The authors concluded that in this pilot study pre-operative fibrinogen concentrate infusion reduced bleeding after CABG without evidence of post-operative hypercoagulability.  They stated that larger studies are needed to ensure safety and confirm efficacy of prophylactic fibrinogen treatment in cardiac surgery.

Mercier and Bonnet (2010) reviewed the optimal use of blood products and clarified the indications for prohemostatic drugs in obstetric hemorrhage.  The literature emphasizes the usefulness of transfusing packed red blood cells, fresh frozen plasma and platelets earlier and in defined ratios to prevent dilutional coagulopathy during obstetric hemorrhage.  It seems reasonable to use blood products for transfusion earlier and in a 1: 1 fresh frozen plasma: red blood cell ratio during acute obstetric hemorrhage; however, this analysis is mainly based on trauma literature.  Fibrinogen concentrate should be added if the fibrinogen plasma level remains below 1.0 g/L and perhaps even as soon as it falls below 1.5 to 2.0 g/L; the addition of tranexamic acid (1 g) is cheap, likely to be useful and appears safe.  Data on the proactive administration of platelets are insufficient to recommend this practice routinely.  Presently, recombinant factor VIIa (60 to 90 microg/kg) is advocated only after failure of other conventional therapies, including embolization or conservative surgery, but prior to obstetric hysterectomy.  The authors stated that prospective randomized controlled trials are highly desirable to examine the use of clotting factors and other prohemostatic drugs for the management of obstetric hemorrhage.

Wikkelsoe and colleagues (2012) described the protocol of a randomized controlled trial (FIB-PPH trial) to examine the effects of fibrinogen concentrate as initial treatment for post-partum hemorrhage (PPH).  In this placebo-controlled, double-blind, multi-center trial, parturients with primary PPH are eligible following vaginal delivery in case of manual removal of placenta (blood loss [greater than or equal to] 500 ml) or manual exploration of the uterus after the birth of placenta (blood loss [greater than or equal to] 1,000 ml).  Caesarean sections are also eligible in case of peri-operative blood loss [greater than or equal to] 1,000 ml.  The exclusion criteria are known inherited hemostatic deficiencies, pre-partum treatment with anti-thrombotics, pre-pregnancy weight less than 45 kg or refusal to receive blood transfusion.  Following informed consent, patients will be randomly allocated to either early treatment with 2 g fibrinogen concentrate or 100 ml isotonic saline (placebo).  Hemostatic monitoring with standard laboratory coagulation tests and thrombo-elastography (TEG, functional fibrinogen and RapidTEG) is performed during the initial 24 hours.  Primary outcome is the need for blood transfusion.  To examine a 33 % reduction in the need for blood transfusion a total of 245 patients will be included.  Four university affiliated public tertiary care hospitals will include patients during a 2-year period.  Adverse events including thrombosis are assessed in accordance with International Conference on Harmonisation (ICH) - good clinical practice (GCP).  The authors concluded that a widespread belief in the benefits of early fibrinogen substitution in cases of PPH has led to increased off-label use.  The FIB-PPH trial is investigator-initiated and aims to provide an evidence-based platform for the recommendations of the early use of fibrinogen concentrate in PPH.

Schochl et al (2010) reported the treatment of major trauma using mainly coagulation factor concentrates.  This retrospective analysis included trauma patients who received greater than or equal to 5 units of red blood cell concentrate within 24 hours.  Coagulation management was guided by thromboelastometry (ROTEM).  Fibrinogen concentrate was given as first-line hemostatic therapy when maximum clot firmness (MCF) measured by FibTEM (fibrin-based test) was less than 10 mm.  Prothrombin complex concentrate (PCC) was given in case of recent coumarin intake or clotting time measured by extrinsic activation test (EXTEM) greater than 1.5 times normal.  Lack of improvement in EXTEM MCF after fibrinogen concentrate administration was an indication for platelet concentrate.  The observed mortality was compared with the mortality predicted by the trauma injury severity score (TRISS) and by the revised injury severity classification (RISC) score.  Of 131 patients included, 128 received fibrinogen concentrate as first-line therapy, 98 additionally received PCC, while 3 patients with recent coumarin intake received only PCC.  Twelve patients received FFP and 29 received platelet concentrate.  The observed mortality was 24.4 %, lower than the TRISS mortality of 33.7 % (p = 0.032) and the RISC mortality of 28.7 % (p > 0.05).  After excluding 17 patients with traumatic brain injury, the difference in mortality was 14 % observed versus 27.8 % predicted by TRISS (p = 0.0018) and 24.3 % predicted by RISC (p = 0.014).  The authors concluded that ROTEM-guided hemostatic therapy, with fibrinogen concentrate as first-line hemostatic therapy and additional PCC, was goal-directed and fast.  A favorable survival rate was observed.  Moreover, they stated that prospective, randomized trials to investigate this therapeutic alternative further appear warranted.

Wafaisade et al (2012) examined if blood component transfusion and hemostatic drug administration during acute trauma care have changed in daily practice during the recent years.  The multi-center trauma registry of the German Society for Trauma was retrospectively analyzed for primarily admitted patients older than 16 years with an Injury Severity Score greater than or equal to 16 who had received at least 5 red blood cell (RBC) units between emergency room arrival and intensive care unit admission.  Administration of FFP and platelet units has been documented since 2002, and use of hemostatic drugs since 2005.  From 2002 to 2009 (n = 2,813), the FFP:RBC ratio increased from 0.65 to 0.75 (p = 0.02) and the platelet:RBC ratio from 0.04 to 0.09 (p < 0.0001).  A constant increase was also observed regarding the overall use of hemostatic drugs (n = 1,811; 2005 to 2009) as these were administered to 43.4 % of the patients in 2005 and to 60.7 % in 2009 (p < 0.0001).  In particular, the administration of fibrinogen concentrate (2005: 17.0 %, 2009: 45.6 %; p < 0.0001) and recombinant factor VIIa (2005: 1.9 %, 2009: 6.3 %; p = 0.04) showed a marked increase.  However, mortality rates remained unchanged during the 8-year study period.  The authors concluded that therapy of bleeding trauma patients has changed in Germany during the recent years toward more aggressive coagulation support.  This development continues although grades of evidence are still low regarding most of the changes reported in this study.  They stated that randomized controlled trials are needed with respect to blood component therapy using pre-defined ratios and to the administration of hemostatic drugs commonly used for the severely injured.

Grottke (2012) noted that trauma-induced coagulopathy is a frequent complication in severely injured patients.  To correct coagulopathy and restore hemostasis, these patients have traditionally been treated with fresh frozen plasma, but in the last decade, there has been a shift from empirical therapy to targeted therapy with coagulation factor concentrates and other hemostatic agents.  This investigator highlighted emerging therapeutic options and controversial topics.  Early administration of the anti-fibrinolytic medication tranexamic acid was shown in the multi-center CRASH-2 trial to be an effective and inexpensive means of decreasing blood loss.  Numerous retrospective and experimental studies have shown that the use of coagulation factor concentrates decreases blood loss and may be useful in reducing the need for transfusion of allogeneic blood products.  In particular, early use of fibrinogen concentrate and thrombin generators has a positive impact on hemostasis.  However, the use of prothrombin complex concentrate to correct trauma-induced coagulopathy has also been associated with a potential risk of serious adverse events.  The author concluded that current evidence in trauma resuscitation indicated a potential role for coagulation factor concentrates and other hemostatic agents in correcting trauma-induced coagulopathy.  They stated that despite a shift towards such transfusion strategy, there remains a shortage of data to support this approach.

Ziegler et al (2013) stated that use of allogeneic blood products to treat pediatric trauma may be challenged, particularly in relation to safety.  These researchers reported successful treatment of a child with severe abdominal and pelvic injuries with preemptive fibrinogen supplementation followed by rotational thromboelastometry (ROTEM)-guided, goal-directed hemostatic therapy.  Fibrinogen concentrate was administered (total dose: 2 g), while transfusion of fresh frozen plasma and platelet concentrate was avoided.  Activated partial thromboplastin time was prolonged and Quick values were low but ROTEM clotting time values remained normal, therefore, no thrombin-generating drugs were considered necessary.  The authors concluded that this case showed the potential for hemostatic treatment with coagulation factor concentrates to be applied to pediatric trauma.

Wafaisade et al (2013) examined if the administration of fibrinogen concentrate (FC) in severely injured patients was associated with improved outcomes.  Patients documented in the Trauma Registry of the German Society for Trauma Surgery (primary admissions, Injury Severity Score [ISS] greater than or equal to 16) who had received FC during initial care between emergency department (ED) arrival and intensive care unit admission (FC+) were matched with patients who had not received FC (FC-).  The matched-pairs analysis yielded two comparable cohorts (n = 294 in each group) with a mean ISS of 37.6 ± 13.7 (FC+) and 37.1 ± 13.3 (FC-) (p = 0.73); the mean age was 40 ± 17 versus 40 ± 16 (p = 0.72), respectively.  Patients were predominantly male (71.1 % in both groups, p = 1.0).  On ED arrival, hypotension (systolic blood pressure, less than or equal to 90 mm Hg) occurred in 51.4 % (FC+) and 48.0 % (FC-) (p = 0.41), and base excess was -7.4 ± 5.3 mmol/L for FC+ and was -7.5 ± 6.2 mmol/L for FC- (p = 0.96).  Patients were administered 12.8 ± 14.3 (FC+) versus 11.3 ± 10.0 (FC-) packed red blood cell units (p = 0.20).  Thromboembolism occurred in 6.8 % (FC+) versus 3.4 % (FC-) (p = 0.06), and multi-organ failure occurred in 61.2 % versus 49.0 % (p = 0.003), respectively. Whereas 6-hour mortality was 10.5 % for FC+ versus 16.7 % for FC- (p = 0.03), the mean time to death was 7.5 ± 14.6 days versus 4.7 ± 8.6 days (p = 0.006).  The overall hospital mortality rate was 28.6 % versus 25.5 % (p = 0.40), respectively.  The authors concluded that this was the first study to investigate the effect of FC administration in bleeding trauma.  In this large population of severely injured patients, the early use of FC was associated with a significantly lower 6-hour mortality and an increased time to death, but also an increased rate of multi-organ failure.  A reduction of overall hospital mortality was not observed in patients receiving FC.

In a single-center, prospective, placebo-controlled, double-blind study, Rahe-Meyer et al (2013) examined if fibrinogen concentrate can reduce blood transfusion when given as intra-operative, targeted, first-line hemostatic therapy in bleeding patients undergoing aortic replacement surgery.  Patients aged 18 years or older undergoing elective thoracic or thoraco-abdominal aortic replacement surgery involving cardiopulmonary bypass were randomized to fibrinogen concentrate or placebo, administered intra-operatively.  Study medication was given if patients had clinically relevant coagulopathic bleeding immediately after removal from cardiopulmonary bypass and completion of surgical hemostasis.  Dosing was individualized using the fibrin-based thrombo-elastometry test.  If bleeding continued, a standardized transfusion protocol was followed.  A total of 29 patients in the fibrinogen concentrate group and 32 patients in the placebo group were eligible for the efficacy analysis.  During the first 24 hours after the administration of study medication, patients in the fibrinogen concentrate group received fewer allogeneic blood components than did patients in the placebo group (median, 2 versus 13 U; p < 0.001; primary endpoint).  Total avoidance of transfusion was achieved in 13 (45 %) of 29 patients in the fibrinogen concentrate group, whereas 32 (100 %) of 32 patients in the placebo group received transfusion (p < 0.001).  There was no observed safety concern with using fibrinogen concentrate during aortic surgery.  The authors concluded that hemostatic therapy with fibrinogen concentrate in patients undergoing aortic surgery significantly reduced the transfusion of allogeneic blood products.  Moreover, they stated that larger multi-center studies are needed to confirm the role of fibrinogen concentrate in the management of peri-operative bleeding in patients with life-threatening coagulopathy.

In a prospective, randomized, open-label study, Tanaka et al (2014) compared hematologic and transfusion profiles between the first-line acquired fibrinogen (FIB) replacement and platelet transfusion in post-cardiac surgical bleeding.  A total of 20 adult patients who underwent valve replacement or repair and fulfilled preset visual bleeding scale were randomized to 4 g of FIB or 1 unit of apheresis platelets.  Primary end-points included hemostatic condition in the surgical field and 24-hour hemostatic product usage.  Hematologic data, clinical outcome, and safety data were collected up to the 28th day post-operative visit.  In patients who received the first-line FIB concentrate (n = 10), the visual bleeding scale improved after intervention, and the incidence of platelet transfusion and total plasma donor exposure were lower compared to the platelet group (n = 10).  Post-intervention FIB level was statistically higher (209 mg/dL versus 165 mg/dL) in the FIB group than in the platelet group, but platelet count and prothrombin were lower.  There were no statistical differences in the post-operative blood loss and red blood cell transfusion between 2 groups.  The authors concluded that these preliminary data indicated that the primary FIB replacement may potentially reduce the incidence of platelet transfusion and the number of donor exposures.  These preliminary findings need to be validated by well-designed studies.

Gielen et al (2014) performed a systematic review and meta-analysis to define the association between fibrinogen levels and blood loss after cardiac surgery. A database search (January 2013) was performed on publications assessing the association between pre- and post-operative fibrinogen levels and post-operative blood loss in adult patients undergoing cardiac surgery. Cohort studies and case-control studies were eligible for inclusion. The main outcome was the pooled correlation coefficient, calculated via Fisher's Z transformation scale, in a random-effects meta-analysis model stratified for the time-point at which fibrinogen was measured. A total of 20 studies were included. The pooled correlation coefficient of studies (n = 9) concerning pre-operative fibrinogen levels and post-operative blood loss was -0.40 (95 % confidence interval [CI]: -0.58 to -0.18), pointing towards more blood loss in patients with lower pre-operative fibrinogen levels. Among papers (n = 16) reporting on post-operative fibrinogen levels and post-operative blood loss, the pooled correlation coefficient was -0.23 (95 % CI: -0.29 to -0.16). The authors concluded that the findings of this meta-analysis indicated a significant but weak-to-moderate correlation between pre- and post-operative fibrinogen levels and post-operative blood loss in cardiac surgery. They stated that this moderate association calls for appropriate clinical studies on whether fibrinogen supplementation will decrease post-operative blood loss.

Aubron et al (2014) summarized the available literature evaluating the use of FC in the management of severe trauma. Studies reporting the administration of FC in trauma patients published between January 2000 and April 2013 were identified from MEDLINE and from the Cochrane Library. The systematic review identified 12 articles reporting FC usage in trauma patients: 4 case reports, 7 retrospective studies, and 1 prospective observational study; 3 of these were not restricted to trauma patients. The authors concluded that despite methodological flaws, some of the available studies suggested that FC administration may be associated with a reduced blood product requirement. They stated that randomized controlled trials (RCTs) are needed to determine whether FC improves outcomes in pre-hospital management of trauma patients or whether FC is superior to another source of fibrinogen in early hospital management of trauma patients.

In June 2017, Fibryga, a human fibrinogen concentrate, was approved by the U.S Food and Drug Administration for the treatment of acute bleeding episodes in adults and adolescents with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia. However, Fibryga is not indicated for dysfibrinogenemia. 

Two clinical trials (FORMA 01 and FORMA 02) formed the basis for the safety and efficacy for Fibryga. The FORMA 01 was a randomized, phase 2 crossover study in which 22 subjects (ranging in age 12 to 53 years; 6 adolescents and 16 adults) with congenital fibrinogen deficiency compared the pharmacokinetics (PK) and pharmacodynamics (PD) of Fibryga to the comparable U.S. licensed fibrinogen concentrate product, RiaSTAP.  Each subject received a single intravenous 70 mg/kg dose of Fibryga and the comparator product. Blood samples were drawn from the subjects to determine the fibrinogen activity at baseline and up to 14 days after the infusion. The incremental in vivo recovery (IVR) was determined from levels obtained up to 4 hours post-infusion. The median incremental IVR was a 1.8 mg/dL (range 1.1 – 2.6 mg/dL) increase per mg/kg. The median in vivo recovery indicated that a dose of 70 mg/kg will increase patients’ fibrinogen plasma concentration by approximately 125 mg/dL. No difference in fibrinogen activity was observed between males and females. There was no difference in the pharmacokinetics of Fibryga between adults and adolescents (12-17 years of age) (FDA, 2017).

An interim analysis of the FORMA 02 was used for the FDA-approved indications of Fibryga. The FORMA 02 is an ongoing prospective, uncontrolled phase 3, open-label, multicenter clinical study involving 13 patients (ranging in age 13 to 53 years; 2 adolescents and 11 adults) with congenital fibrinogen deficiency (afibrinogenemia and hypofibrinogenemia), and was used to establish safety and efficacy of Fibryga .  Of the 22 evaluable bleeding events, 21 (95%) were rated as having a good or excellent efficacy. For 1 bleeding event, the investigator’s assessment was missing. The median number of infusions for the bleeding events was 1. Two (9%) bleeding events required 2 infusions. None of the bleeding events required more than 2 infusions. The most common adverse reactions observed in more than one subject in the clinical study (> 5%) were vomiting, weakness and pyrexia (FDA, 2017). 

According to the prescribing information, the dosing, duration, and frequency of administration for Fibryga should be individualized based on the extent of bleeding, laboratory values, and the clinical condition of the patient. The recommended target fibrinogen plasma level is 100 mg/dL for minor bleeding and 150 mg/dL for major bleeding. The patient’s fibrinogen level should be monitored during treatment with Fibryga. Additional infusions of Fibryga should be administered if the plasma fibrinogen level is below the accepted lower limit (80 mg/dL for minor bleeding, 130 mg/dL for major bleeding) of the target level until hemostasis is achieved. (FDA, 2017). See appendix for additional dosing information. 

Bleeding Associated with Aortic Reconstruction and Deep Hypothermic Circulatory Arrest

Hanna and associates (2016) noted that human FC (HFC) is approved by the FDA for use at 70 mg/kg to treat congenital afibrinogenemia. In a prospective, pilot, off-label study, these researchers examined if this dose of HFC increases fibrinogen levels in the setting of high-risk bleeding associated with aortic reconstruction and deep hypothermic circulatory arrest (DHCA).  A total of 22 patients undergoing elective proximal aortic reconstruction with DHCA were administered 70 mg/kg HFC upon separation from cardio-pulmonary bypass (CPB).  Fibrinogen levels were measured at baseline, just before, and 10 minutes after HFC administration, on skin closure, and the day after surgery.  The primary study outcome was the difference in fibrinogen level immediately after separation from CPB, when HFC was administered, and the fibrinogen level 10 minutes following HFC administration.  Additionally, post-operative thromboembolic events were assessed as a safety analysis.  The mean baseline fibrinogen level was 317 ± 49 mg/dL and fell to 235 ± 39 mg/dL just before separation from CPB.  After HFC administration, the fibrinogen level rose to 331 ± 41 mg/dL (p < 0.001) and averaged 372 ± 45 mg/dL the next day.  No post-operative thromboembolic complications occurred.  The authors concluded that administration of 70 mg/kg HFC upon separation from CPB raised fibrinogen levels by approximately 100 mg/dL without an apparent increase in thrombotic complications during proximal aortic reconstruction with DHCA.  Moreover, they stated that further prospective study in a larger cohort of patients will be needed to definitively determine the safety and evaluate the effectiveness of HFC as a hemostatic adjunct during these procedures.

Individuals with Acquired Fibrinogen Deficiency Undergoing Abdominal Surgery

Roy and colleagues (2019) noted that cytoreductive surgery (CRS) with hyper-thermic intra-peritoneal chemotherapy for pseudomyxoma peritonei (PMP) is associated with excessive bleeding and acquired fibrinogen deficiency.  Maintaining plasma fibrinogen may support hemostasis.  In a prospective, off-label, single-center, randomized, controlled phase-II clinical trial, these researchers compared the safety and efficacy of human fibrinogen concentrate (HFC) versus cryoprecipitate as fibrinogen sources for bleeding patients with acquired fibrinogen deficiency undergoing PMP CRS. Patients undergoing PMP surgery with predicted intra-operative blood loss of greater than or equal to 2 L received human fibrinogen concentrate (HFC; 4 g) or cryoprecipitate (2 pools of 5 units, containing approximately 4.0 to 4.6 g fibrinogen), repeated as needed.  The primary end-point was a composite of intra-operative and post-operative efficacy, graded using objective 4-point scales and adjudicated by an independent committee.  One hundred percent of patients receiving HFC (95 % CI: 83.9 to 100.0, n = 21) or cryoprecipitate (84.6 to 100.0, n = 22) achieved hemostatic success.  HFC demonstrated non-inferior efficacy (p = 0.0095; post-hoc) and arrived in the operating room 46 mins faster.  There were significantly greater mean increases with HFC versus cryoprecipitate in plasma fibrinogen (0.78 versus 0.35 g/L; p < 0.0001) and FIBTEM A20 (3.33 versus 0.93 mm; p = 0.003).  Factor XIII, factor VIII, and von Willebrand factor activity were maintained throughout surgery.  Only RBC were transfused intra-operatively (median units: HFC group, 1.0; cryoprecipitate group, 0.5). Thrombo-embolic events were detected with cryoprecipitate only.  Safety was otherwise comparable between groups. The authors concluded that human fibrinogen concentrate was effective in maintaining hemostasis in patients with acquired fibrinogen deficiency undergoing CRS for PMP. HFC is available for use faster than cryoprecipitate and has a comparable safety profile, with the possible exception of thrombo-embolic events, which were observed only with cryoprecipitate.  Owing to the generalizability of the clinical model used, these results have implications for other surgical settings in which patients acquire fibrinogen deficiency and experience acute bleeding.  These researchers stated that further studies are needed to examine potential differences between the safety profiles of the 2 products.  Moreover, the authors stated that although the findings of this phase-II study demonstrated comparable hemostatic efficacy and non-inferiority of HFC to cryoprecipitate, a confirmatory multi-center study would further strengthen these findings.

Intra-Operative Fibrinogen Concentrate for the Prevention of Bleeding in Neonatal and Infant Cardiac Surgery

Siemens and colleagues (2020) noted that mediastinal bleeding is common following pediatric cardiopulmonary bypass surgery for congenital heart disease; and FC represents a potential therapy for the prevention of bleeding. In a single-center, phase-Ib/IIa, RCT on infants 2.5 to 12 kg undergoing cardiopulmonary bypass surgery, these researchers aimed at demonstrating the feasibility of an intra-operative point-of-care test, rotational thrombo-elastometry, to screen out patients at low risk of post-operative bleeding and then guide individualized FC dosing in high-risk patients as well as determining the dose, safety, and efficacy of intra-operative FC supplementation. Screening occurred intra-operatively 1-hour before bypass separation using the rotational thrombo-elastometry variable fibrinogen thrombo-elastometry maximum clot firmness (FibTEM-MCF; fibrinogen contribution to clot firmness). If FibTEM-MCF was greater than or equal to 7 mm, patients entered the monitoring cohort. If FibTEM-MCF was less than or equal to 6 mm, patients were randomized to receive FC/placebo (2:1 ratio). Individualized FC dose calculation included weight, bypass circuit volume, hematocrit (Hct), and intra-operative measured and desired FibTEM-MCF. The coprimary outcomes, measured 5 mins post-FC administration were FibTEM-MCF (desired range, 8 to 13 mm) and fibrinogen levels (desired range, 1.5 to 2.5 g/L). Secondary outcomes were thrombosis and thrombosis-related major complications and post-operative 24-hour mediastinal blood loss. These researchers enrolled 111 patients (cohort, n = 21; FC, n = 60; placebo, n = 30); mean (SD) age, 6.4 months (5.8); weight, 5.9 kg (2.0). Intra-operative rotational thrombo-elastometry screening effectively excluded low-risk patients, in that none in the cohort-arm (FibTEM-MCF, greater than or equal to 7 mm) demonstrated clinically significant early post-operative bleeding (greater than 10 ml/kg per 4 hours). Among randomized patients, the median (range) FC administered dose was 114 mg/kg (51 to 218). Fibrinogen levels increased from a mean (SD) of 0.91 (0.22) to 1.7 g/L (0.41). The post-dose fibrinogen range was 1.2 to 3.3 g/L (72 % within the desired range). The corresponding FibTEM-MCF values were as follows: pre-dose, 5.3 mm (1.9); post-dose, 13 mm (3.2); 10 patients (8 FC and 2 placebo) exhibited 12 possible thromboses; none was clearly related to FC. There was an overall difference in mean (SD) 24-hour mediastinal drain loss: cohort, 12.6 ml/kg (6.4); FC, 11.6 ml/kg (5.2); placebo, 17.1 ml/kg (14.3; ANOVA; p = 0.02). The authors concluded that they had demonstrated the feasibility, safety, and accuracy of individualized FC dosing during pediatric CPB; however, any future phase-III clinical trial would likely require a similar design, involving intra-operative ROTEM-based screening and individualized dosing. This level of complexity poses significant challenges for a multi-center study; thus, the next step requires scoping feasibility across potential centers, including examining the variation in current practice and quantifying current mediastinal bleeding rates, as well as enthusiasm for such a trial. Moreover, given the risk/benefit profile of this approach, and the lack of alternative therapies, these researchers feel that this is warranted. Finally, any future trial would also require an appropriate health economic analysis, given that the unit cost of FC is 2 to 3× that of cryoprecipitate.

These researchers stated that the safety aspect of this study design provided a limitation in evaluating efficacy. Patients at higher risk of thrombosis were excluded from the early cohorts (n = 25 with shunt-dependent circulations and n = 20 undergoing the arterial switch procedure); however, these patients also represent a cohort at higher risk of bleeding; therefore, these investigators may have under-estimated any efficacy signal. However, this would not occur in a subsequent phase-III clinical trial.

Crighton and Huisman (2021) stated that critically ill children frequently experience bleeding events and hypofibrinogenemia is implicated in adult and pediatric settings as an important risk factor for bleeding. There remains considerable uncertainty in children of all ages around optimal fibrinogen levels and the best fibrinogen replacement strategies. Cryoprecipitate and FC are both administered to prevent and treat bleeding due to hypofibrinogenemia despite a sparse evidence base. These researchers noted that neonates and children continue to be under-represented or under-powered in clinical trials. They stated that further evidence and RCTs in pediatric transfusion medicine are needed, so that, rather than extrapolating from adult studies or basing practice on experience, best and evidence-based practice is delivered.

In a randomized, single-center, pilot study, Tirotta et al (2022) examined if treatment with human FC would decrease the need for component blood therapy and blood loss in neonate and infant patients undergoing cardiopulmonary bypass.  Pediatric patients (n = 30) undergoing elective cardiac surgery were randomized to receive human FC or placebo following cardiopulmonary bypass (CPB) termination.  The primary endpoint was the amount of cryoprecipitate administered.  Secondary endpoints included estimated blood loss during the 24 hours post-surgery; peri-operative blood product transfusion; effects of fibrinogen infusion on global hemostasis, measured by laboratory testing and rotational thrombo-elastometry; and AEs.  No clinically significant differences were identified in baseline characteristics between groups.  A significantly lower volume of cryoprecipitate was administered to the treatment group during the peri-operative period [median (inter-quartile range [IQR]) 0.0 (0.0 to 0.0) cc/kg versus 12.0 (8.2 to 14.3) cc/kg; p < 0.0001] versus placebo.  No difference was observed between treatment groups in blood loss, laboratory coagulation tests, use of other blood components, or incidence of AEs.  FIBTEM amplitude of maximum clot firmness values was significantly higher among patients treated with human FC versus placebo (p ≤ 0.0001).  No significant differences were observed in post-drug HEPTEM, INTEM, and EXTEM results.  Human FC (70 mg/kg) administered after the termination of CPB reduced the need for transfusion with cryoprecipitate in a neonate and infant patient population.

The authors stated that the main drawback of this study was the low patient numbers (n = 30) and the lack of human FC dose ranges tested.  As this was a single-center study, the number of available patients for participation in this trial was limited.  However, these results showed the potential for treatment with human FC in this patient population.  These researchers stated that further studies, including a prospective trial with greater patient numbers is needed and would provide an avenue for future research in pediatric cardiac surgery patients to confirm the findings of this pilot study.  Furthermore, a dose-response study to examine higher doses in this patient population would provide valuable guidance for clinical use of this therapy.  Moreover, due to the limited data for human FC use during cardiac surgery in pediatric patients, these researchers selected normal saline (NS) as the comparator in this study.  Based on these findings, a study randomizing patients to human FC or cryoprecipitate, instead of NS, would also be valuable.  It should also be noted that the findings of this trial may have been influenced by the pre-operative treatment with FFP in patients with an anti-thrombin III deficiency, or by the routine use of post-bypass platelets for all patients.  In addition, the range of surgical types included among the low number of patients in this study may have affected the results.

Peri-Operative Hemorrhage (e.g., Cardiovascular Surgery)

In a randomized, placebo-controlled, double-blind, clinical trial Bilecen and associates (2017) examined if fibrinogen concentrate infusion dosed to achieve a plasma fibrinogen level of 2.5 g/L in high-risk cardiac surgery patients with intra-operative bleeding reduces intra-operative blood loss.  This study was conducted in the Netherlands (February 2011 to January 2015), involving patients undergoing elective, high-risk cardiac surgery (i.e., combined coronary artery bypass graft [CABG] surgery and valve repair or replacement surgery, the replacement of multiple valves, aortic root reconstruction, or reconstruction of the ascending aorta or aortic arch) with intra-operative bleeding (blood volume between 60 and 250 ml suctioned from the thoracic cavity in a period of 5 minutes) were randomized to receive either fibrinogen concentrate or placebo.  Subjects received intravenous, single-dose administration of fibrinogen concentrate (n = 60) or placebo (n = 60), targeted to achieve a post-infusion plasma fibrinogen level of 2.5 g/L.  The primary outcome was blood loss (in mls) between intervention (i.e., after removal of cardio-pulmonary bypass) and closure of chest.  Safety variables (within 30 days) included: in-hospital mortality, myocardial infarction (MI), cerebrovascular accident (CVA) or transient ischemic attack (TIA), renal insufficiency or failure, venous thromboembolism (VTE), pulmonary embolism (PE), and operative complications.  Among 120 patients (mean age of 71 [standard deviation [SD], 10] years, 37 women [31 %]) included in the study, combined CABG and valve repair or replacement surgery comprised 72 % of procedures and had a mean (SD) cardiopulmonary bypass time of 200 minutes (83) minutes. For the primary outcome, median blood loss in the fibrinogen group was 50 ml (inter-quartile range [IQR], 29 to 100 ml) compared with 70 ml (IQR, 33 to 145 ml) in the control group (p = 0.19), the absolute difference 20 ml (95 % CI: -13 to 35 ml).  There were 6 cases of stroke or TIA (4 in the fibrinogen group); 4 MI (3 in the fibrinogen group); 2 deaths (both in the fibrinogen group); 5 cases with renal insufficiency or failure (3 in the fibrinogen group); and 9 cases with re-operative thoracotomy (4 in the fibrinogen group).  The authors concluded that among patients with intra-operative bleeding during high-risk cardiac surgery, administration of fibrinogen concentrate, compared with placebo, resulted in no significant difference in the amount of intra-operative blood loss.

Karkouti and co-workers (2018) stated that coagulopathic bleeding is a serious complication of cardiac surgery to which an important contributor is acquired hypofibrinogenemia (plasma fibrinogen less than 1.5 to 2.0 g/L).  The standard intervention for acquired hypofibrinogenemia is cryoprecipitate, but purified fibrinogen concentrates are also available.  There is little comparative data between the 2 therapies and RCTs are needed.  FIBrinogen REplenishment in Surgery (FIBRES) is a multi-center, randomized (1:1), active-control, single-blinded, phase-III clinical trial in adult cardiac surgical patients experiencing clinically significant bleeding related to acquired hypofibrinogenemia.  The primary objective is to demonstrate that fibrinogen concentrate is non-inferior to cryoprecipitate.  All patients for whom fibrinogen supplementation is ordered by the clinical team within 24 hours of cardiopulmonary bypass will receive 4 g of fibrinogen concentrate or 10 units of cryoprecipitate (dose-equivalent to 4 g), based on random allocation and deferred consent.  The primary outcome is total RBC, platelet and plasma transfusions administered within 24 hours of bypass.  Secondary outcomes include major bleeding, fibrinogen levels and adverse events (AEs) within 28 days.  Enrolment of 1,200 patients will provide greater than 90 % power to demonstrate non-inferiority.  One pre-planned interim analysis will include 600 patients.  The pragmatic design and treatment algorithm align with standard practice, aiding adherence and generalizability.

Li and co-workers (2018) noted that post-operative bleeding remains a frequent complication after cardiovascular surgery and may contribute to serious morbidity and mortality.  Observational studies have suggested a relationship between low endogenous plasma fibrinogen concentration and increased risk of post-operative blood loss in cardiac surgery.  Although the transfusion of fibrinogen concentrate has been increasing, potential benefits and risks associated with peri-operative fibrinogen supplementation in cardiovascular surgery are not fully understood.  In a meta-analysis, these investigators evaluated the effects of fibrinogen concentrate in cardiovascular surgery.  PubMed, Cochrane Library, Ovid Medline, Embase, Web of Science, and China National Knowledge Infrastructure were searched on January 15, 2017, with automated updates searched until February 15, 2018, to identify all RCTs of fibrinogen concentrate, whether for prophylaxis or treatment of bleeding, in adults undergoing cardiovascular surgery.  All RCTs comparing fibrinogen infusion versus any other comparator (placebo/standard of care or another active comparator) in adult cardiovascular surgery and reporting at least 1 pre-defined clinical outcome were included.  The random-effects model was used to calculate risk ratios and weighted mean differences (MDs; 95 % CI) for dichotomous and continuous variables, respectively.  Subgroup analyses by fibrinogen dose and by baseline risk for bleeding were pre-planned.  A total of 8 RCTs of fibrinogen concentrate in adults (n = 597) of mixed risk or high risk undergoing cardiovascular surgery were included.  Compared to placebo or inactive control, peri-operative fibrinogen concentrate did not significantly impact risk of all-cause mortality (RR, 0.41; 95 % CI: 0.12 to 1.38; I = 10 %; p = 0.15).  Fibrinogen significantly reduced incidence of allogeneic RBC transfusion (RR, 0.64; 95 % CI: 0.49 to 0.83; I = 0 %; p = 0.001).  No significant differences were found for other clinical outcomes.  Subgroup analyses were unremarkable when analyzed according to fibrinogen dose, time of infusion initiation, mean cardiopulmonary bypass time, and rotational thrombo-elastometry/fibrinogen temogram use (all p values for subgroup interaction were non-significant).  The authors concluded that current evidence remained insufficient to support or refute routine peri-operative administration of fibrinogen concentrate in patients undergoing cardiovascular surgery.  Fibrinogen concentrate may reduce the need for additional allogeneic blood product transfusion in cardiovascular surgery patients at high risk or with evidence of bleeding.  However, no definitive advantage was found for reduction in risk of mortality or other clinically relevant outcomes.  They stated that the small number of clinical events within existing randomized trials suggested that further well-designed studies of adequate power and duration to measure all-cause mortality, stroke, MI, re-operation, and thrombo-embolic events should be conducted.  They also stated that future studies should address cost-effectiveness relative to standard of care.

On behalf of the Hemostasis and Transfusion Scientific Subcommittee of the European Association of Cardiothoracic Anesthesiology, Erdoes and colleagues (2019) provided an international consensus statement on “The role of fibrinogen and fibrinogen concentrate in cardiac surgery”.  These investigators stated that currently data regarding the safety and efficacy of administering fibrinogen concentrate in cardiac surgery are limited.  Studies are limited by their low sample size and large heterogeneity with regard to the patient population, by the timing of fibrinogen concentrate administration, and by the definition of transfusion trigger and target levels.  Assessment of fibrinogen activity using viscoelastic point-of-care testing shortly before or after weaning from cardiopulmonary bypass in patients and procedures with a high risk of bleeding appeared to be a rational strategy.  In contrast, the use of Clauss fibrinogen test for determination of plasma fibrinogen level can no longer be recommended without restrictions due to its long turn-around time, high inter-assay variability and interference with high heparin levels and fibrin degradation products.  Administration of fibrinogen concentrate for maintaining physiological fibrinogen activity in the case of microvascular post-cardiopulmonary bypass bleeding appeared to be indicated. The authors stated that available evidence does not suggest aiming for supra-normal levels, however; and the use of cryoprecipitate as an alternative to fibrinogen concentrate might be considered to increase plasma fibrinogen levels.  They noted that although conclusive evidence is lacking, fibrinogen concentrate does not seem to increase adverse outcomes (i.e., thrombo-embolic events).  These researchers stated that large, prospective, multi-center studies are needed to better define the optimal peri-operative monitoring tool, transfusion trigger and target levels for fibrinogen replacement in cardiac surgery.

Post-Partum Hemorrhage

In a multi-center, double-blinded, parallel RCT, Wikkelso and colleagues (2015) hypothesized that pre-emptive treatment with FC reduces the need for RBC transfusion in patients with (PPH. These investigators assigned subjects with severe PPH to a single dose of FC or placebo (saline).  A dose of 2 g or equivalent was given to all subjects independent of body weight and the FC at inclusion.  The primary outcome was RBC transfusion up to 6 weeks post-partum; secondary outcomes were total blood loss, total amount of blood transfused, occurrence of re-bleeding, hemoglobin of less than 58 g/L, RBC transfusion within 4 hours, 24 hours, and 7 days, and as a composite outcome of “severe PPH”, defined as a decrease in hemoglobin of greater than 40 g/L, transfusion of at least 4 units of RBCs, hemostatic intervention (angiographic embolization, surgical arterial ligation, or hysterectomy), or maternal death.  Of the 249 randomized subjects, 123 of 124 in the fibrinogen group and 121 of 125 in the placebo group were included in the intention-to-treat analysis.  At inclusion the subjects had severe PPH, with a mean blood loss of 1,459 (S.D. of 476) ml and a mean FC of 4.5 (S.D. of 1.2) g/L.  The intervention group received a mean dose of 26 mg/kg FC, thereby significantly increasing FC compared with placebo by 0.40 g/L (95 % CI: 0.15 to 0.65; p = 0.002).  Post-partum blood transfusion occurred in 25 (20 %) of the fibrinogen group and 26 (22 %) of the placebo group (relative risk [RR], 0.95; 95 % CI: 0.58 to 1.54; p = 0.88). These researchers found no difference in any pre-defined secondary outcomes, per-protocol analyses, or adjusted analyses.  No thromboembolic events were detected.  The authors concluded that there is no evidence to support the use of 2 g FC as pre-emptive treatment for severe PPH in patients with normo-fibrinogenemia.

Zaidi and colleagues (2020) noted that fibrinogen levels drop early in PPH, and low fibrinogen levels predict outcomes. There is increasing interest in replacing fibrinogen early in severe PPH. In a systematic review, these researchers examined if early fibrinogen replacement therapy would improve outcomes in severe PPH. They searched the following databases from inception to June 2019: CDSR and CENTRAL (The Cochrane Library), Medline, Embase, CINAHL, PubMed, Transfusion Evidence Library, LILACS, Web of Science Conference Proceedings Citation Index-Science, ClinicalTrials.gov and the WHO International Clinical Trials Registry Portal. These investigators included RCTs and well-designed controlled observational studies where fibrinogen replacement therapy was given early (within 90 mins of bleeding) compared with standard protocol in pregnant women of greater than 24 weeks' gestation who developed PPH, defined as estimated blood loss greater than or equal to 500 ml up to 24 hours post-delivery. Two independent reviewers extracted and reviewed the data on the primary outcome of allogeneic blood transfusion at 24 hours after intervention and secondary outcomes including all-cause mortality, rate of thrombosis, and the need for surgical and non-surgical interventions. These researchers identified 5 eligible studies: 2 completed (total of 299 women) RCTs comparing FC with placebo, and 3 ongoing RCTs. There was no completed study assessing cryoprecipitate transfusion. There was variation of: timings of intervention administration; severity of PPH; fibrinogen doses and use of tranexamic acid. There was insufficient evidence that early administration of fibrinogen in PPH reduced the need for allogeneic blood transfusion at 24 hours (risk rato [RR] 0.83; 95 % CI: 0.54 to 1.26, p = 0.38) (2 trials, 299 participants) or improved other outcomes. Both studies were under-powered to answer the outcomes. The authors concluded that there is a lack of evidence that early fibrinogen replacement therapy improved outcomes in PPH. These researchers stated that future studies are needed to address this, under-pinned by data on the optimal fibrinogen dose, protocol-driven approaches versus targeted therapy, and cost-effectiveness of cryoprecipitate versus FC therapy in PPH.

In a randomized, double-blind, placebo-controlled, multi-center study, Ducloy-Bouthors and associates (2021) examined the safety and benefits of early human FC in the treatment of PPH. Subjects included patients with persistent PPH after vaginal delivery requiring a switch from oxytocin to prostaglandins (PGs). Within 30 mins after introduction of PGs, patients received either 3-g FC or placebo. Main outcome measures were failure as composite primary efficacy endpoint: at least 4 g/dL of hemoglobin decrease and/or transfusion of at least 2 units of packed RBCs within 48 hours following investigational medicinal product administration. Secondary endpoints were PPH evolution, need for hemostatic procedures and maternal morbidity-mortality within 6 ± 2 weeks after delivery. A total of 437 patients were included in this trial: 224 received FC and 213 received placebo. At inclusion, blood loss (877 ± 346 ml) and plasma fibrinogen (4.1 ± 0.9 g/L) were similar in both groups (mean ± SD). Failure rates were 40.0 % and 42.4 % in the FC and placebo groups, respectively (OR = 0.99) after adjustment for center and baseline plasma fibrinogen; (95 % CI: 0.66 to 1.47; p = 0.96). No significant differences in secondary efficacy outcomes were observed. The mean plasma fibrinogen was unchanged in the FC group and decreased by 0.56 g/L in the placebo group. No thromboembolic or other relevant adverse effects were reported in the FC group versus 2 in the placebo group. The authors concluded that as previous placebo-controlled studies findings, early and systematic administration of 3-g FC did not reduce blood loss, transfusion needs or post-partum anemia; however, it did prevent plasma fibrinogen decrease without any subsequent thromboembolic events.

Deleu et al (2022) stated that FC is used for the treatment of severe PPH despite limited evidence of its effectiveness in obstetric settings.  In a population-based, cohort study, these researchers examined the association between administration of FC and maternal outcomes in women with severe PPH.  This secondary analysis of the EPIMOMS prospective, population-based study, examining severe maternal morbidity, as defined by national expert consensus (2012 to 2013, 182,309 deliveries, France), included all women with severe PPH and transfused with RBCs during active bleeding.  The primary endpoint was maternal near-miss or death, and the secondary endpoint was the total number of RBC units transfused.  These researchers studied FC administration as a binary variable and then by the timing of its administration.  They used multi-variable analysis and propensity score matching to account for potential indication bias.  Among the 730 women with severe PPH and transfused, 313 (42.9 %) received FC, and 142 (19.5 %) met near-miss criteria or died.  The risk of near-miss or death was not significantly lower among the women treated with FC than among those not treated, in either the multi-variable analysis (adjusted RR = 1.03; 95 % CI: 0.72 to 1.49; p = 0.855) or the propensity score analysis (RR = 0.85; 95 % CI: 0.55 to 1.32; p = 0.477).  Among women treated with FC, administration more than 3 hours after RBC transfusion started was associated with a higher risk of near-miss or death than administration before or within 30 mins after the transfusion began (adjusted RR = 2.07; 95 % CI: 1.10 to 3.89; p = 0.024).  Results were similar for the secondary endpoint.  The authors concluded that the use of FC in severe PPH needing RBC transfusion during active bleeding was not associated with improved maternal outcomes.

Trauma-Associated Hemorrhage

Mengoli and colleagues (2017) stated that hemorrhage following injury is associated with significant morbidity and mortality.  The role of fibrinogen concentrate in trauma-induced coagulopathy has been the object of intense research in the last 10 years and has been systematically analyzed in this review.  A systematic search of the literature identified 6 retrospective studies and 1 prospective one, involving 1,650 trauma patients.  There were no randomized trials.  Meta-analysis showed that fibrinogen concentrate had no effect on overall mortality (RR: 1.07, 95 % CI: 0.83 to 1.38).  Although the meta-analytic pooling of the current literature evidence suggested no beneficial effect of fibrinogen concentrate in the setting of severe trauma, the quality of data retrieved was poor and the final results of ongoing randomized trials will help to further elucidate the role of fibrinogen concentrate in traumatic bleeding.

Curry and associates (2018) conducted a blinded, randomized, placebo-controlled trial at 5 UK major trauma centers with adult trauma patients with active bleeding who required activation of the major hemorrhage protocol.  Participants were randomized to standard major hemorrhage therapy plus 6 g of fibrinogen concentrate or placebo; 27 of 39 participants (69 %; 95 % CI: 52 to 83 %) across both arms received the study intervention within 45 minutes of admission.  There was some evidence of a difference in the proportion of participants with fibrinogen levels of greater than or equal to 2 g/L between arms (p = 0.10).  Fibrinogen levels in the fibrinogen concentrate (FgC)-arm rose by a mean of 0.9 g/L (SD, 0.5) compared with a reduction of 0.2 g/L (SD, 0.5) in the placebo-arm and were significantly higher in the FgC-arm (p < 0.0001) at 2 hours.  Fibrinogen levels were not different at day 7.  Transfusion use and thromboembolic events were similar between arms.  All-cause mortality at 28 days was 35.5 % (95 % CI: 23.8 to 50.8 %) overall, with no difference between arms.  The authors concluded that early delivery of fibrinogen concentrate within 45 minutes of admission was not feasible.  Although evidence pointed to a key role for fibrinogen in the treatment of major bleeding, researchers need to recognize the challenges of timely delivery in the emergency setting.  Moreover, they stated that future studies must explore barriers to rapid fibrinogen therapy, focusing on methods to reduce time to randomization, using “off-the-shelf” fibrinogen therapies (such as extended shelf-life cryoprecipitate held in the emergency department or fibrinogen concentrates with very rapid reconstitution times) and limiting the need for coagulation test-based transfusion triggers.

Peralta and Chowdary (2019) noted that uncontrolled bleeding in trauma secondary to a combination of surgical bleeding and trauma-induced complex coagulopathy is a leading cause of death; PCCs, recombinant activated factor seven (rFVIIa) and recombinant human prothrombin act as procoagulants by increasing thrombin generation and fibrinogen concentrate aids stable clot formation.  These investigators summarized the current evidence for procoagulant use in the management of bleeding in trauma, and data and evidence gaps for routine clinical use.  Retrospective and prospective studies of PCCs (± fibrinogen concentrate) have demonstrated a decreased time to correction of trauma coagulopathy and decreased RBC transfusion with no obvious effect on mortality or thrombo-embolic outcomes.  PCCs in a porcine model of dilutional coagulopathy demonstrated a sustained increase in thrombin generation, unlike recombinant human prothrombin, which showed a transient increase and has been studied only in animals.  In other retrospective studies, there was a suggestion that lower doses of PCCs may be effective in the setting of acquired coagulopathy.  The authors concluded that there is increasing evidence that early correction of coagulopathy has survival benefits, and the use of procoagulants as first-line therapy has the potential benefit of rapid access and timely treatment.  This requires confirmation in prospective studies.

Seebold and colleagues (2019) stated that fibrinogen is one of the first coagulation factors to be depleted during traumatic hemorrhage, and evidence suggested hypo-fibrinogenemia resulted in poor outcomes.  A number of fibrinogen replacement products are currently available, with no clear consensus on the ideal product to use in severe traumatic hemorrhage.  These researchers hypothesized that it will be possible to rapidly administer fibrinogen concentrate (FC) guided by rotational thrombo-elastometry (ROTEM) FIBTEM A5 in patients presenting with trauma hemorrhage.  They examined 36 consecutive patients with trauma admitted to a level 1 trauma center in Australia who received FC as part of their initial resuscitation.  ROTEM analysis was conducted at various time-points from emergency department (ED) admission to 48 hours after admission.  The primary outcome was time to administration of FC after identification of hypo-fibrinogenemia using ROTEM FIBTEM A5.  Data were collected on quantity and timing of product transfusion, demographics, Injury Severity Score and laboratory values of coagulation. Spearman rank order correlation was used to determine the correlation between FIBTEM A5 and Clauss fibrinogen (FibC).  A total of 36 patients received FC as their initial form of fibrinogen replacement during the study.  Patients were hypo-fibrinogenemic by both FIBTEM A5 (6 mm) and FibC (1.7 g/L) on presentation to the ED.  It took a median of 22 mins (IQR, 17 to 30 mins) from time of a FIBTEM A5 analysis to FC administration.  Both parameters increased significantly (p < 0.05) by 24 hours after admission.  The authors concluded that the findings of this study suggested that administration of FC represented a rapid and feasible method to replace fibrinogen in severe traumatic hemorrhage.  However, the optimal method for replacing fibrinogen in traumatic hemorrhage is controversial and large multi-center RCTs are needed to provide further evidence.  This study provided baseline data to inform the design of further clinical trials examining fibrinogen replacement in traumatic hemorrhage.

Stabler and colleagues (2020) examined the evidence regarding the safety and efficacy of preemptive and goal-directed FC in the management of trauma-related hemorrhage. In a systematic review, these investigators searched PubMed, Medline, Embase, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform. All trial designs, except individual case reports, that examined the preemptive or goal-directed use of FC for trauma-related bleeding/coagulopathy, in patients older than 16 years, were included. For the included RCTs comparing FC with control, meta-analysis was carried out and a risk-of bias-assessment was completed using the Cochrane Methodology and Preferred Reporting Items Systematic Reviews and Meta-analysis guidelines. A total of 2,743 studies were identified; 26 were included in the systematic review, and 5 RCTs (n = 238) were included in the meta-analysis. For the primary outcome of mortality, there was no statistically significant difference between the groups, with 22 % and 23.4 % in the FC and comparator arms, respectively (risk ratio [RR], 1.00; 95 % CI: 0.39 to 2.56; p = 0.99). Furthermore, there was no statistical difference between FC and control in packed RBC, FFP, or platelet transfusion requirements, and thromboembolic events (TEEs). Overall, the quality of evidence was graded as low-to-moderate because of concerns with risk of bias, imprecision, and inconsistency. The authors concluded that further high-quality, adequately powered studies are needed to examine the impact of FC in trauma, with a focus on administration as early as possible from the point of entry into the trauma system of care. Level of Evidence = II.

Itagaki and associates (2021) noted that the use of FC enables the rapid and strong supply of fibrinogen in the serum without the need for confirming ABO compatibility; therefore, FC may change the result of a life-saving procedure compared with an ordinary transfusion strategy consisting of an allogenic transfusion. Thus far, there have been many RCTs that have been carried out on the use of FC in elective surgery; however, there is a lack of studies in emergency settings. Recently, RCTs for the use of FC in trauma or post-partum situations have increased. By summarizing these results, these investigators will update the information regarding the safety and efficacy of the use of FC that has been previously reported and examine the effect on newly reported, as mortality rate. This meta-analysis will be one of the first attempts to report the effect of the administration of FC in emergency situations on survival rate. In this study, these researchers will focus on emergency bleeding situations such as trauma, gastro-intestinal (GI) hemorrhage, surgery (regardless of the type), and post-partum, the analysis will summarize multiple aspects. This is the first attempt to conduct a systematic review and meta-analysis on the safety and efficacy of using FC for emergency hemorrhage; thus, these findings will provide front-line physicians with updated information regarding the safety and efficacy of FC in life-saving situations.

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References