Fibrinogen concentrate administration attributes to significant reductions of blood loss and transfusion requirements in thoracic aneurysm repair

The Choice between Plasma-Based Common Coagulation Tests and Cell-Based Viscoelastic Tests in Monitoring Hemostatic Competence: Not an either-or Proposition

There has been a significant interest in the last decade in the use of viscoelastic tests (VETs) to determine the hemostatic competence of bleeding patients. Previously, common coagulation tests (CCTs) such as the prothrombin time (PT) and partial thromboplastin time (PTT) were used to assist in the guidance of blood component and hemostatic adjunctive therapy for these patients. However, the experience of decades of VET use in liver failure with transplantation, cardiac surgery, and trauma has now spread to obstetrical hemorrhage and congenital and acquired coagulopathies. Since CCTs measure only 5 to 10% of the lifespan of a clot, these assays have been found to be of limited use for acute surgical and medical conditions, whereby rapid results are required. However, there are medical indications for the PT/PTT that cannot be supplanted by VETs. Therefore, the choice of whether to use a CCT or a VET to guide blood component therapy or hemostatic adjunctive therapy may often require consideration of both methodologies. In this review, we provide examples of the relative indications for CCTs and VETs in monitoring hemostatic competence of bleeding patients.

Therapeutic Application of Fibrinogen in Spine Surgery: A Review Article

BACKGROUND

The aim of this review is to investigate current uses of fibrinogen as a tool to reduce operative and postoperative blood loss in different surgical fields especially orthopedic spine surgery. This is a systematic review.

METHODS

MEDLINE (via Ovid 1946 to June 1, 2020) and Embase (via Ovid 1947 to June 1, 2020) were searched using the keywords "fibrinogen", "surgery", and "spine" for relevant studies. The search strategy used text words and relevant indexing to identify articles discussing the use of fibrinogen to control surgical blood loss.

RESULTS

The original literature search yielded 407 articles from which 68 duplications were removed. Three hundred thirty-nine abstracts and titles were screened. Results were separated by surgical specialties.

CONCLUSIONS

Multiple studies have looked at the role of fibrinogen for acute bleeding in the operative setting. The current evidence regarding the use of fibrinogen concentrate in spine surgery is promising but limited, even though this is a field with the potential for severe hemorrhage. Further trials are required to understand the utility of fibrinogen concentrate as a first-line therapy in spine surgery and to understand the importance of target fibrinogen levels and subsequent dosing and administration to allow recommendations to be made in this field.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.

Efficacy of resuscitation with fibrinogen concentrate and platelets in traumatic hemorrhage swine model

BACKGROUND

This study compared the resuscitation effects of platelets and fibrinogen concentrate (FC) on coagulation and hemodynamics in pigs with traumatic hemorrhage and reduced platelet counts.

METHODS

Thirty pigs (40 ± 3 kg) were anesthetized and catheterized with an apheresis catheter to remove platelets using the Haemonetics 9000 (Haemonetics, Braintree, MA). Afterward, a femur fracture was induced, followed by hemorrhage of 35% the estimated blood volume. Pigs were then randomized to be resuscitated with 5% human albumin (12.5 mL/kg), FC (250 mg/kg, 12.5 mL/kg), or platelets collected from apheresis (11.0 ± 0.5 mL/kg). Animals were monitored for 2 hours or until death. Blood samples were collected before (baseline [BL]) and after apheresis, after hemorrhage, and after resuscitation to assess changes in hemodynamics and coagulation using Rotem.

RESULTS

No change in mean arterial pressure (MAP) or heart rate (HR) was observed by platelet apheresis. Hemorrhage reduced MAP to 57% ± 5% and elevated HR to 212% ± 20% of BL (both p < 0.05). Resuscitation with albumin, FC, or platelets did not revert MAP or HR to BL. Platelet counts were reduced by apheresis from BL 383 ± 20 × 10/μL to 141 ± 14 × 10/μL and were reduced further after resuscitation with albumin (88 ± 18 × 10/μL) or FC (97 ± 13 × 10/μL, all p < 0.05), but improved with platelet resuscitation (307 ± 24 × 10/μL). Fibrinogen concentration was reduced by apheresis from BL 225 ± 9 mg/dL to 194 ± 8 mg/dL, fell after albumin infusion (134 ± 11 mg/dL), increased to 269 ± 10 mg/dL after FC resuscitation (all p < 0.05), and was not affected by platelet resuscitation. Rotem α-angle decreased from 79 ± 2 degrees to 69 ± 1 degrees by apheresis and hemorrhage (p < 0.05), and recovered similarly by resuscitation with FC (87 ± 1 degrees) or platelets (78 ± 2 degrees), but not by albumin (63 ± 3 degrees). Similar responses were observed in Rotem maximum clot firmness.

CONCLUSION

In this traumatic hemorrhage swine model, low-volume resuscitation with FC or platelets was similarly effective in restoring coagulation.

Early administration of fibrinogen concentrates improves the short-term outcomes of severe pelvic fracture patients

Aim

Hemorrhage from pelvic fracture is a major cause of mortality after blunt trauma. Several studies have suggested that early fibrinogen supplementation improves outcomes of traumatic hemorrhage. Thus, we revised our massive transfusion protocol (MTP) in April 2013 to include early off‐label administration of fibrinogen concentrate. The objective of this study was to evaluate the impact of the revision on the short‐term outcomes of pelvic fracture patients.

Methods

This was a single‐center, retrospective, cohort study. A total of 224 consecutive pelvic fracture patients hospitalized in Saitama Medical Center (Saitama, Japan), 115 before the revision (Group E) and 109 after (Group L), were enrolled. Characteristics of the patients were compared between the groups. Impacts of the revision were evaluated by hazard ratios adjusted for characteristics, injury severity, and coagulation status using Cox's multivariate proportional hazard model. The impact was also evaluated by log–rank test and relative risk of 28‐day mortality between the groups.

Results

The characteristics were equivalent between the groups. The multivariate analysis revealed that the revision of MTP was significantly related to improved survival with an adjusted hazard ratio (95% confidence interval) of 0.45 (0.07–0.97). The log–rank test gave χ²‐test values of 5.2 (P = 0.022) and 6.7 (P = 0.009), and the relative risks were 0.37 (0.15–0.91) and 0.33 (0.13–0.84), in patients with all Injury Severity Scores and Injury Severity Score ≥21, respectively.

Conclusion

The revision of MTP to include aggressive off‐label treatment with fibrinogen concentrate was related to improved short‐term outcomes of severe pelvic fracture patients. However, due to the limitations of the study, the improvement could not be attributed totally to the revision.

[Hemorrhage treatment: Evaluation of the proper use of fibrinogen concentrate]

An increase in fibrinogen concentrate prescriptions was noticed in 2015 after several guidelines regarding their use were published. We tried to evaluate if they were used appropriately. To evaluate the conformity of the prescriptions to these guidelines, we searched for each prescription if a dosage of blood fibrinogen was made, if its result was below the limit recommended to prescribe fibrinogen concentrate, and if the posology was in line with the recommendations. Effect and security of the treatment was also evaluated. We analyzed 202 prescriptions for 117 patients. The indications are respected except for one prescription for which we could not find it. The blood fibrinogen is measured for 76% of the prescriptions, 59% of the results are below the limit recommended to prescribe. The posology is conforming to the guidelines for 73% of the prescriptions, it is below the dose recommended for 20%. Patients who were prescribed low doses seemed less at risk than the others which questions the necessity of the prescriptions. The guidelines respect depends on the emergency of the prescription situation. It would be interesting to conduct a prospective study to better explain why doses below those recommended are prescribed.

Pre-emptive administration of fibrinogen concentrate contributes to improved prognosis in patients with severe trauma

Background

Patients with severe trauma often present with critical coagulopathy, resulting in impaired hemostasis, massive hemorrhage, and a poor survival prognosis. The efficacy of hemostatic resuscitation in correcting coagulopathy and restoring tissue perfusion has not been studied. We assessed a novel approach of pre-emptive administration of fibrinogen concentrate to improve critical coagulopathy in patients with severe trauma.

Methods

We retrospectively compared blood transfusion volumes and survival prognosis between three groups of patients with trauma, with an Injury Severity Score (ISS) ≥26 over three consecutive periods: group A, no administration of fibrinogen concentrate; group B, administration of 3 g of fibrinogen concentrate after evaluation of trauma severity and a plasma fibrinogen level <1.5 g/L; group C, pre-emptive administration of 3 g of fibrinogen concentrate immediately on patient arrival based on prehospital information, including high-severity injury or assessed need for massive transfusion before measurement of fibrinogen.

Results

∼56% of patients with an ISS ≥26 and transfused with red blood cell concentrates ≥10 units, had hypofibrinogenemia (fibrinogen <1.5 g/L) on arrival. Patients who received fibrinogen concentrate in group C showed significantly higher fibrinogen levels after treatment with this agent than those in group B (2.41 g/L vs 1.88 g/L; p=0.01). Although no significant difference was observed in blood transfusion volumes between the groups, the 30-day survival of patients in group C (all, and those with an ISS ≥26) was significantly better than in group A (p<0.05). The 48-hour mortality rate in patients with an ISS ≥26 was significantly lower in group C than in group A (8.6% vs 22.9%; p=0.005). Further, among patients with an ISS ≥41, the overall mortality was significantly lower in group C than in group A (20% vs 50%; p=0.02).

Conclusion

Pre-emptive administration of fibrinogen concentrate for patients with trauma with critical coagulopathy may contribute to improved survival.

Level of evidence

Level IV.

Coagulation complications following trauma

Traumatic injury is one of the leading causes of death, with uncontrolled hemorrhage from coagulation dysfunction as one of the main potentially preventable causes of the mortality. Hypothermia, acidosis, and resuscitative hemodilution have been considered as the significant contributors to coagulation manifestations following trauma, known as the lethal triad. Over the past decade, clinical observations showed that coagulopathy may be present as early as hospital admission in some severely injured trauma patients. The hemostatic dysfunction is associated with higher blood transfusion requirements, longer hospital stay, and higher mortality. The recognition of this early coagulopathy has initiated tremendous interest and effort in the trauma community to expand our understanding of the underlying pathophysiology and improve clinical treatments. This review discusses the current knowledge of coagulation complications following trauma.

Insufficient fibrinogen response following free flap surgery is associated with bleeding complications

Background: Microvascular tissue transfer has become a safe and reliable tool in the reconstructive armamentarium, yielding high success rates. However, little is known about the changes in coagulation after free tissue transfer and their potential impact on morbidity. Methods: Fibrinogen concentration and platelet count among other values were available and assessed in 139 undergoing free tissue transfer before, immediately after, and 1-3 as well as 8-11 days after surgery. In patients undergoing urgent revision for either bleeding or microvascular thrombosis, blood samples were drawn directly before re-exploration. Results: In the patients without any surgical revision and in those with thrombosis of the microvascular pedicle, both fibrinogen concentration and platelet count increased significantly during the early and late post-operative window. Patients that developed bleeding necessitating re-exploration showed an inadequate increase in fibrinogen levels, resulting in significantly lower concentrations compared to the other two groups. There were no significant differences in platelet count or PTT between these groups. Conclusion: Free flap surgery induces acute and subacute changes in coagulation, comparable to other major surgeries and severe injuries. This leads to an increase in platelet count and fibrinogen over the post-operative course. Patients that developed bleeding requiring surgical re-exploration showed an insufficient increase in fibrinogen, resulting in significantly lower fibrinogen levels. Therefore, monitoring and correction of fibrinogen levels might aid in preventing or treating bleeding complications following free flap surgery.

The hemostatic disturbance in patients with acute aortic dissection: A prospective observational study

Coagulopathy is still a frequent complication in the surgical treatment of acute aortic dissection. However, the physiopathology of surgically induced coagulopathy has never been systematically and comprehensively studied in patients with acute aortic dissection. The aim of the present study was to describe the perioperative hemostatic system in patients with acute aortic dissection.The 87 patients who underwent aortic arch surgery for acute Stanford type A aortic dissection from January 2013 to September 2015 were enrolled in this study. The perioperative biomarkers of hemostatic system were evaluated using standard laboratory tests and enzyme-linked immunosorbent assays (ELISAs) at 5 time points: anesthesia induction (T1), lowest nasopharyngeal temperature (T2), protamine reversal (T3), 4 hours after surgery (T4), and 24 hours after surgery (T5).The ELISAs biomarkers revealed activation of coagulation (thrombin-antithrombin III complex [TAT] and prothrombin fragment 1 + 2 [F1 + 2] were elevated), suppression of anticoagulation (antithrombin III [AT III] levels were depressed), and activation of fibrinolysis (plasminogen was decreased and plasmin-antiplasmin complex [PAP] was elevated). The standard laboratory tests also demonstrated that surgery resulted in a significant reduction in platelet counts and fibrinogen concentration.Systemic activation of coagulation and fibrinolysis, and inhibition of anticoagulation were observed during the perioperative period in patients with acute aortic dissection. Indeed, these patients exhibited consumption coagulopathy and procoagulant state perioperatively. Therefore, we believe that this remarkable disseminated intravascular coagulation (DIC)-like coagulopathy has a high risk of bleeding and may influence postoperative outcome of patients with acute aortic dissection.

Fibrinogen concentrate administration inhibits endogenous fibrinogen synthesis in pigs after traumatic hemorrhage

BACKGROUND

Fibrinogen plays a central role in coagulation and falls to critical levels early after trauma. Administration of fibrinogen concentrate (FC) to improve hemostasis after severe bleeding seems beneficial, but it is unclear whether its use introduces excessive fibrinogen with a potential risk of thrombosis. This study investigated changes of endogenous fibrinogen metabolism from FC administration following traumatic hemorrhage in pigs.

METHODS

Anesthetized, instrumented pigs were randomized into lactated Ringer's (LR) solution only and LR plus FC groups (n = 7 each). Femur fracture of each pig's left leg was followed by hemorrhage of 60% total blood volume and resuscitation with LR (3× bled volume, LR group) or LR plus FC at 250 mg/kg (LR-FC group). Afterward, a constant infusion of stable isotopes 1-C-phenylalanine (phe, 6 hours) and d5-phe (3 hours) was performed with hourly blood sampling and subsequent gas chromatography-mass spectrometry analysis to quantify fibrinogen synthesis and breakdown rates, respectively. Blood gas and coagulation indices (thromboelastography) were measured on intermittent blood samples, and hemodynamics was continuously monitored. Animals were euthanized after the 6-hour isotope period.

RESULTS

Mean arterial pressure decreased by 50% after hemorrhage but improved after LR resuscitation in both groups. Hemorrhage and LR resuscitation reduced total protein, hematocrit, fibrinogen, and platelets to 50% of baseline values. Moreover, hemorrhage and resuscitation decreased fibrinogen concentration (207 ± 6 vs. 132 ± 7 mg/dL) and clot strength (72 ± 2 vs. 63 ± 2 mm) in both groups (p < 0.05). FC administration restored plasma fibrinogen concentrations and clot strength within 15 minutes, while no changes occurred in the LR group. Fibrinogen synthesis rates in the LR-FC group (1.3 ± 0.2 mg/kg/h) decreased versus the LR group (3.1 ± 0.5; p < 0.05), whereas fibrinogen breakdown rates were similar.

CONCLUSION

Our data suggest an effective feedback mechanism that regulates host fibrinogen availability and thereby suggests that acute thrombosis from FC administration is an unlikely risk.

Massive hemorrhage management-a best evidence topic report

Introduction

Massive hemorrhage remains a major cause of potentially preventable deaths. Better control of bleeding could improve survival rates by 10%–20%. Transfusion intervention concepts have been formulated in order to minimize acute traumatic coagulopathy. These interventions still have not been standardized and vary among medical centers.

Materials and Methods

Based on a literature search using free term keywords and Medical Subject Heading (MeSH) index, we analyzed published articles addressing massive hemorrhage, component therapy, fresh whole blood, and fibrinogen from the year 2000 onward, in journals with impact factor >1.000, in Medline, PubMed, and Google Scholar. The evidence was grouped into topics including laboratory testing and transfusion interventions/viscoelastic assays vs standard laboratory tests, the effect of component therapy on patient outcome, the effect of warm fresh whole blood on patient outcome, and the effects of fibrinogen in severe bleeding. The obtained information was compared, evaluated, confronted, and was focused on to present an adequate and individual-based massive hemorrhage management approach.

Results

Viscoelastic whole-blood assays are superior to standard coagulation blood tests for the identification of coagulopathy and for guiding decisions on appropriate therapy in patients with severe bleeding. Replacement of plasma, red blood cells, platelets, and fibrinogen in a ratio of 1:1:1:1 has appeared to be the best substitution for lost whole blood. There is no evidence that cryoprecipitate improves the outcome of patients with severe hemorrhage. Current literature promotes the transfusion of warm fresh whole blood, which seems to be superior to the component therapy in certain clinical situations. Some authors recommend that fibrinogen and other coagulation factors be administered according to the viscoelastic attributes of the blood clot.

Conclusion

This best-evidence topic report brings comprehensive information about massive hemorrhage management.

Accelerated activation of the coagulation pathway during cardiopulmonary bypass in aortic replacement surgery: a prospective observational study

Background

Any form of surgery or tissue damage causes release of tissue factor into the circulation. This may lead to the accelerated consumption of coagulation factors, resulting in severe consumptive coagulopathy. In this study, we compared the molecular markers involved in coagulation activation during cardiopulmonary bypass (CPB) between patients who underwent aortic replacement surgery and those who underwent valve surgery.

Methods

This prospective observational study was performed in each 14 patients who underwent aortic replacement surgery or valve surgery. We evaluated the differences in the levels of fibrinogen, activated factor VII (FVIIa), thrombin–antithrombin complex (TAT), and soluble fibrin monomer complex (SFMC) during surgery between these two groups.

Results

The change in fibrinogen levels showed no difference between the groups. The magnitude of increase in TAT was much larger in patients who underwent aortic replacement surgery than in those who underwent valve surgery (173.6 vs. 49.4 ng/mL; p = 0.0001). More importantly, the elevation of FVIIa was significantly higher in patients who underwent aortic replacement (28.5 vs. 19.0 mU/mL; p = 0.0122). The magnitude of increase in SFMC was also larger in the aortic replacement surgery.

Conclusions

The activation of coagulation during CPB was dramatically higher in the aortic replacement surgery compared with the valve surgery, probably owing to the activation of the extrinsic coagulation pathway in the former. This could potentially exacerbate consumptive coagulopathy after CPB termination in patients who underwent aortic replacement, possibly resulting in massive hemorrhage due to impaired hemostasis.

Role of prothrombin complex concentrate in perioperative coagulation therapy

Prothrombin complex concentrate (PCC) is a term to describe pharmacological products that contain lyophilized, human plasma-derived vitamin K-dependent factors (F), FII, FVII, FIX, FX, and various amounts of proteins C and S. PCCs can be rapidly reconstituted in a small volume (20 ml for about 500 international units (IU)) at bedside and administered regardless of the patient's blood type. PCCs are categorized as 4-factor PCC if they contain therapeutic amounts of FVII, and 3-factor PCC when FVII content is low. In addition, activated PCC which contains activated FVII and FX with prothrombin is available for factor VIII bypassing therapy in hemophilia patients with inhibitors. Currently, 4-factor PCC is approved for the management of bleeding in patients taking warfarin, but there has been increasing use of various PCCs in the treatment of acquired perioperative coagulopathy unrelated to warfarin therapy and in the management of bleeding due to novel oral anticoagulants. There is also an ongoing controversy about plasma transfusion and its potential hazards including transfusion-related lung injury (TRALI). Early fixed ratio plasma transfusion has been implemented in many trauma centers in the USA, whereas fibrinogen concentrate and PCC are preferred over plasma transfusion in some European centers. In this review, the rationales for including PCCs in the perioperative hemostatic management will be discussed in conjunction with plasma transfusion.