Perioperative coagulation management in a patient with afibrinogenemia undergoing liver transplantation

Budd-Chiari syndrome associated with congenital afibrinogenaemia reversed after orthotopic liver transplant

A woman in her mid-20s, a known case of congenital afibrinogenaemia, presented with abdominal pain and distension. She was diagnosed with decompensated liver cirrhosis due to Budd-Chiari syndrome. She underwent deceased donor liver transplantation. Preoperatively, her serum fibrinogen level was undetectable and prothrombin time and international normalised ratio (INR) were unrecordable. Intraoperatively, she was given thromboelastography-guided human fibrinogen concentrate. Postoperatively, her fibrinogen, prothrombin time and INR normalised rapidly. This report summarises the rare occurrence of a complication of hypercoagulability (Budd-Chiari syndrome) in the setting of congenital hypocoagulability (congenital afibrinogenaemia). In this report, we discuss the simultaneous management of these two clinical problems and the curative role of liver transplantation.

Liver transplantation as a novel strategy for resolution of congenital afibrinogenemia in a pediatric patient

Fibrinogen replacement therapy is a treatment mainstay for patients with afibrinogenemia and significant bleeding. A male infant with congenital afibrinogenemia and several spontaneous hemarthroses commenced cryoprecipitate prophylaxis but developed severe urticarial reactions. He transitioned to a human fibrinogen concentrate (HFC) (RiaSTAP® , CSL Behring; 70 mg/kg biweekly) but continued experiencing hemarthroses (estimated annualized bleeding rate [ABR]: 5-6) and severe anaphylactic reactions, despite pre- and postinfusion medications. Following switching to a new HFC (Fibryga® , Octapharma; 50 mg/kg biweekly), ABR was 0-1 with no further infusion reactions. Aged 9 years, because of limited quality of life, development of obesity and fatty liver disease, he underwent orthotopic liver transplant (OLT) under HFC coverage. Pharmacokinetic analysis guided presurgical fibrinogen levels > 150 mg/dL. No intraoperative HFC infusions were required. Coagulation profile and fibrinogen levels remained within normal limits during and posttransplant. To our knowledge, this is the first pediatric report of afibrinogenemia successfully treated with OLT.

Genetic Variants in the FGB and FGG Genes Mapping in the Beta and Gamma Nodules of the Fibrinogen Molecule in Congenital Quantitative Fibrinogen Disorders Associated with a Thrombotic Phenotype

Fibrinogen is a hexameric plasmatic glycoprotein composed of pairs of three chains (Aα, Bβ, and γ), which play an essential role in hemostasis. Conversion of fibrinogen to insoluble polymer fibrin gives structural stability, strength, and adhesive surfaces for growing blood clots. Equally important, the exposure of its non-substrate thrombin-binding sites after fibrin clot formation promotes antithrombotic properties. Fibrinogen and fibrin have a major role in multiple biological processes in addition to hemostasis and thrombosis, i.e., fibrinolysis (during which the fibrin clot is broken down), matrix physiology (by interacting with factor XIII, plasminogen, vitronectin, and fibronectin), wound healing, inflammation, infection, cell interaction, angiogenesis, tumour growth, and metastasis. Congenital fibrinogen deficiencies are rare bleeding disorders, characterized by extensive genetic heterogeneity in all the three genes: FGA, FGB, and FGG (enconding the Aα, Bβ, and γ chain, respectively). Depending on the type and site of mutations, congenital defects of fibrinogen can result in variable clinical manifestations, which range from asymptomatic conditions to the life-threatening bleeds or even thromboembolic events. In this manuscript, we will briefly review the main pathogenic mechanisms and risk factors leading to thrombosis, and we will specifically focus on molecular mechanisms associated with mutations in the C-terminal end of the beta and gamma chains, which are often responsible for cases of congenital afibrinogenemia and hypofibrinogenemia associated with thrombotic manifestations.

Congenital afibrinogenemia in a patient with vascular abnormalities and a novel variant: clinical-molecular description and literature review

: The objective is to report a patient with congenital afibrinogenemia and vascular abnormalities and also review the clinical and molecular issues. The female proband, diagnosed with congenital afibrinogenemia, was admitted at a hospital due to a hemorrhagic shock. Angiotomography revealed ectasias from ascending branch to the abdominal aorta, with multiple calcifications and atheroma. Clinical exome identified a homozygous novel pathogenic variant in FGG gene. In our review the main symptom, at diagnosis, was umbilical cord bleeding and the degree of clinical involvement varied from asymptomatic to severe. The FGA gene was the most affected and possible hot spots were observed. Variants considered as loss of function were the most frequent. The association of vascular abnormalities in a patient with congenital afibrinogenemia alerts for a closer follow-up of vascular issues in these patients.

Women With Congenital Hypofibrinogenemia/Afibrinogenemia: From Birth to Death

Congenital fibrinogen disorders are a group of most frequent rare coagulation disorder, characterized by deficiency and/or defects in the fibrinogen molecule. Quantitative disorders include hypofibrinogenemia and afibrinogenemia. Due to their specific physiological characteristics, female patients tend to have congenital hypofibrinogenemia/afibrinogenemia, such as spontaneous recurrent abortion, menorrhagia, infertility, antepartum and postpartum hemorrhage, and so on. Current studies of congenital hypofibrinogenemia/afibrinogenemia mainly focus on different types of fibrinogen mutations, etiology/pathogenesis, and some rare case reports of the diseases. So far, there is no study available to systematically review the specific features of female patients with congenital bleeding disorders. This review aims to deal with hematological, gynecologic and obstetric issues, and relevant clinical management of congenital hypofibrinogenemia/afibrinogenemia at different life stages of female patients. We believe this review provides valuable reference for clinicians in the field of hematology, obstetrics, as well as gynecology.

Administering RiaSTAP for Congenital Afibrinogenemia During Liver Transplant

Liver transplant has occasionally been performed in the presence of congenital afibrinogenemia and has been rarely used to treat it. Historically, to safely manage coagulopathy during transplant, these patients have been administered a combination of fresh frozen plasma and cryoprecipitate. In this case report, we discuss the first reported use of recombinant fibrinogen to treat such a patient and the decision-making process considered to balance the thrombotic and hemorrhagic risks.

Thromboembolism in patients with congenital afibrinogenaemia

Frequent arterial and venous thromboembolism in patients with congenital afibrinogenaemia (CA) is neither understood nor is a safe and effective treatment established. It was our objective to report on the clinical observations and laboratory data contributing to the understanding of the frequency, physiopathology, prognosis and treatment of CA. We observed the long-term clinical course and laboratory data in a cohort of four patients with CA and thromboembolic complications, and conducted a systematic review retrieving all available data. Four patients with CA developed recurrent and extensive arterial and venous thromboembolism (TE) from an age of 25–51 years. In two patients, a treatment strategy targeting at maintaining constantly measurable fibrinogen (Fbg) levels (≥0.5 g/l) either by regular Fbg replacement or by orthotopic liver transplantation resulted in long-term remissions. Radiological imaging documented resolved arterial thrombi after 6–12 months. In contrast, recurrent thromboembolic events were observed in two other patients with infrequent Fbg replacement. A systematic review of the literature revealed 48 reports of TE in patients with CA (median age at first event 31 years), and a favourable outcome in most patients with frequent application of Fbg, aimed at constantly measurable trough levels. Present data suggests that patients with CA are at high risk of arterial and venous thromboembolic events, probably caused by thrombin excess owing to lack of thrombin scavenging by Fbg/fibrin. Regular low-dose Fbg replacement might be a safe and effective treatment option in patients with CA and thromboembolic complications.

Note: Preliminary data of this report were presented as oral presentation at the XXV Congress of the International Society on Thrombosis and Haemostasis, June 20th to 25th, Toronto, Canada.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Influence of autologous blood transfusion in liver transplantation in patients with hepatitis B on the function and hemorheology of red blood cells

The present study aimed to characterize the function and hemorheology of red blood cells (RBCs) recovered during liver transplantation surgery in patients with hepatitis B and decompensation. A total of 15 hepatitis B patients with decompensation who underwent liver transplantation surgery were included in the present study. Blood samples were recovered during the liver transplantation surgery using an Autologous Blood Recovery System. The morphology and structure of RBCs were characterized and compared between pre-operative and recovered blood samples. In addition, the physiological functions of RBCs were measured and compared between pre-operative and recovered blood samples. No significant differences in the morphological score, 2,3-diphosphoglycerate, Na+K+-ATPase, Ca2+-ATPase, Mg2+-ATPase, malondialdehyde and osmotic fragility were identified between RBCs in the pre-operative and recovered blood samples. The level of free hemoglobin in RBCs of the recovered blood samples was significantly higher than in the pre-operative blood samples (P<0.05). Medium- and high-shear blood viscosities in the recovered blood samples were significantly lower than those observed in the pre-operative blood samples (P<0.05). Casson viscosity in the recovered blood samples was significantly higher compared with the pre-operative blood samples. However, no significant differences (P>0.05) in the low-shear blood viscosity, plasma viscosity, relative blood viscosity, erythrocyte aggregation index or Casson yield stress were identified between recovered and pre-operative blood samples. These findings suggested that autologous blood transfusion in liver transplantation surgery in patients with hepatitis B and decompensation had no significant influence on the morphology, structure, function and hemorheology of RBCs.

Congenital afibrinogenemia: from etiopathogenesis to challenging clinical management

INTRODUCTION

Congenital afibrinogenemia belongs to the group of autosomal recessive bleeding disorders and represents the absolute deficiency of fibrinogen detected by an antigenic test. This can lead to severe clinical manifestations of the disorder. Therefore, it is very important to take afibrinogenemia into account in the process of the differential diagnostics of the patients.

AREAS COVERED

The authors provide a summary of currently available literature about afibrinogenemia. They collected the information from the scientific journals dedicated to thrombosis and hemostasis and searched world-wide databases. Expert commentary: The most frequent clinical manifestation of this disorder is mucosal bleeding, but musculoskeletal bleeding pattern, gynecologic and obstetric issues, spontaneous bleeding, episodes provoked by minor injury or any other intervention, and even paradoxical thromboembolic events have been published. Afibrinogenemia is the consequence of mutations of the homozygous or compound heterozygous type in gene FGA, FGB or FGG encoding fibrinogen. Pregnant women with a family history, or with a history of consanguinity ought to be properly counselled. However, primary prophylaxis of bleeding events is not suggested. The article deals with actual information about afibrinogenemia contributing to its early diagnosis and effective treatment, which in many cases requires multidisciplinary approach.

Thromboelastography predicts risks of obstetric complication occurrence in (hypo)dysfibrinogenemia patients under non-pregnant state

Congenital (hypo)dysfibrinogenemia patients may have obstetric complications during their pregnancies. This study aimed to evaluate thromboelastography (TEG) as a potential tool for assessing the tendency for obstetric complications in those patients in a non-pregnant state. A total of 22 female subjects with congenital (hypo)dysfibrinogenemia were recruited. Nine subjects had histories of obstetric complications and the other 13 subjects had at least one uneventful pregnancy without obstetric complications as yet. Detailed clinical investigation and phenotype/genotype detection were carried out, and both kaolin-activated TEG and functional fibrinogen TEG (FF-TEG) were applied in all subjects. Significant differences were identified in all TEG parameters except for R and angle between these two groups (P < 0.05) by covariance analysis. Receiver operating characteristic (ROC) analysis of discrimination between these two groups of patients was performed for TEG parameters. Significantly high odds ratio (OR) of obstetric complications occurrence were demonstrated in K ≥ 3.8 min, maximum amplitude (MA) ≤ 54.2 mm, comprehensive index (CI) ≤ -3 (11.67, 95% CI 1.527-89.121, P < 0.05 in all), and MA-CFF ≤ 12.1 mm (20.00, 95% confidence interval (95% CI) 1.967-203.322, P = 0.002). Moreover, MA-CFF had better prognostic performance, with a corresponding area under the receiver operating curve of 0.923 (range 0.815-1.031, P = 0.001). This study suggests that (hypo)dysfibrinogenemia patients with values outside of the cut-off values of TEG assays under non-pregnant state may have a higher risk of obstetric complications occurring when they are pregnant. No parameters under non-pregnant state in clinical laboratory have ever been reported to be risk factors for obstetric complication occurrence in (hypo)dysfibrinogenemia patients. This study explored such parameters in TEG assays and found that parameters of TEG assays under non-pregnant status might predict the occurrence of obstetric complications, which could provide physicians with important information about whether fibrinogen replacement therapy is required, so as to prevent the occurrence of obstetric complications, especially for patients who are asymptomatic in daily life.

Congenital afibrinogenemia: a case report of a spontaneous hepatic hematoma

INTRODUCTION

Afibrinogenemia is a rare coagulation disorder. Clinical features of spontaneous bleeding, bleeding after minor trauma, or after surgery have been described as well as thrombo-embolic complications. In this article, we presented the case of a 19-year old female with congenital afibrinogenemia who was admitted with a spontaneous intrahepatic hematoma.

CONCLUSIONS

Supportive treatment including transfusion and fibrinogen administration, associated with repeated packing surgeries and selective embolization, were successfully performed.

In vitro rescue of FGA deletion by lentiviral transduction of an afibrinogenemic patient's hepatocytes

BACKGROUND

Congenital afibrinogenemia is a rare inherited autosomal recessive disorder in which a mutation in one of three genes coding for the fibrinogen polypeptide chains Aα, Bβ and γ results in the absence of a functional coagulation protein. A patient with congenital afibrinogenemia, resulting from an FGA homozygous gene deletion, underwent an orthotopic liver transplant that resulted in complete restoration of normal hemostasis. The patient's explanted liver provided a unique opportunity to further investigate a potential novel treatment modality.

OBJECTIVE

To explore a targeted gene therapy approach for patients with congenital afibrinogenemia.

METHODS AND RESULTS

At the time of transplant, the patient's FGA-deficient hepatocytes were isolated and transduced with lentiviral vectors encoding the human fibrinogen Aα-chain. FGA-transduced hepatocytes produced fully functional fibrinogen in vitro.

CONCLUSIONS

Orthotopic liver transplantation is a possible rescue treatment for failure of on-demand fibrinogen replacement therapy. In addition, we provide evidence that hepatocytes homozygous for a large FGA deletion can be genetically modified to restore Aα-chain protein expression and secrete a functional fibrinogen hexamer.

Two novel mutations in the fibrinogen γ nodule

INTRODUCTION

Congenital dysfibrinogenemia and hypofibrinogenemia are rare diseases characterized by inherited abnormality in the fibrinogen molecule, resulting in functional defects (dysfibrinogenemia) or low fibrinogen plasma levels (hypofibrinogenemia).

MATERIALS AND METHODS

We have described two abnormal fibrinogens - fibrinogen Hranice (γ Phe204Val) and Praha IV (γ Ser313Gly). The carrier of the Hranice mutation was a 40-year-old female with low fibrinogen levels. The carrier of the Praha IV mutation was a 42-year-old man with a history of idiopathic thrombosis, low functional fibrinogen levels, and a prolonged thrombin time.

RESULTS

Fibrin polymerization kinetics measurement was normal in both cases (after the addition of either thrombin or reptilase), as well as was fibrinolysis. Scanning electron microscopy and confocal microscopy revealed significantly wider fibers in both cases, when compared with fibers prepared from healthy control samples. Although both cases are situated in the γ-nodule, they manifested differently. While the γ Ser313Gly mutation manifested as dysfibrinogenemia with a thrombotic background, the γ Phe204Val mutation manifested as hypofibrinogenemia without clinical symptoms. The mutation sites of both fibrinogens are in highly conserved regions of the fibrinogen γ chains. γ Ser313 is situated in a class 16:18 β hairpin and is involved in hydrogen bonding with γ Asp320. γ Phe204 is situated in an inverse γ turn and may be involved in π-π interactions.

CONCLUSIONS

Both mutations cause conformational changes in fibrinogen, which lead either to impaired fibrinogen assembly (fibrinogen Hranice) or abnormal fibrinogen function (fibrinogen Praha IV).

Changes in fibrinogen availability and utilization in an animal model of traumatic coagulopathy

Background

Impaired haemostasis following shock and tissue trauma is frequently detected in the trauma setting. These changes occur early, and are associated with increased mortality. The mechanism behind trauma-induced coagulopathy (TIC) is not clear. Several studies highlight the crucial role of fibrinogen in posttraumatic haemorrhage. This study explores the coagulation changes in a swine model of early TIC, with emphasis on fibrinogen levels and utilization of fibrinogen.

Methods

A total of 18 landrace pigs were anaesthetized and divided into four groups. The Trauma-Shock group (TS) were inflicted bilateral blast femoral fractures with concomitant soft tissue injury by a high-energy rifle shot to both hind legs, followed by controlled exsanguination. The Shock group (S) was exposed to shock by exsanguination, whereas a third group was exposed to trauma only (T). A fourth group (C) served as control. Physiological data, haematological measurements, blood gas analyses and conventional coagulation assays were recorded at baseline and repeatedly over 60 minutes. Thrombelastometry were performed by means of the tissue factor activated ExTEM assay and the platelet inhibiting FibTEM assay. Data were statistically analysed by repeated measurements analyses method.

Results

A significant reduction of fibrinogen concentration was observed in both the TS and S groups. INR increased significantly in the S group and differed significantly from the TS group. Maximum clot firmness (MCF) of the ExTEM assay was significantly reduced over time in both TS and S groups. In the FibTEM assay a significant shortening of the clotting time and an increase in MCF was observed in the TS group compared to the S group.

Conclusion

Despite a reduction in clotting capability measured by ExTEM MCF and a reduced fibrinogen concentration, extensive tissue trauma may induce an increased fibrin based clotting activity that attenuates the hypocoagulable tendency in exsanguinated animals.

Standardization of thromboelastography: a report from the TEG-ROTEM working group

Laboratory evaluation of bleeding disorders has been performed with the standard clotting assays such as the PT and PTT for several decades. Our improved understanding of the process of blood coagulation has now revealed the important role played by the cellular elements such as platelets, monocytes and red blood cells. The need for a test that can assess clotting in a more 'global' manner, beyond the initiation of clot formation, has led to greater interest in assays such as thrombin generation and thromboelastography. Even though there are several publications using thromboelastography it remains a research tool as the methodology is not standardized. In an attempt to show reproducibility and consistency using thromboelastography, a group of investigators from different countries joined hands to form the TEG-ROTEM Working Group. Two studies were performed using PRP and FVIII deficient plasma and an intrinsic pathway activator. This article summarizes the results of the first international effort at standardization of thromboelastography. Both of the instruments using this technology (TEG(®) and ROTEM(®)) were used. Nine laboratories from countries around the globe participated in this effort. The results showed a significant inter-laboratory variance with CV's greater than 10%. Although these results were not satisfactory, this has been the first effort to standardize this methodology and significant work remains to be done to improve reliability and reproducibility. These studies were performed on PRP and the results may be more reliable when preformed on whole blood samples. We believe that it is important to continue this work so that we may investigate the usefulness and potential applications of thromboelastography in the evaluation of bleeding and thrombosis.

Treatment of congenital fibrinogen deficiency: overview and recent findings

Afibrinogenemia is a rare bleeding disorder with an estimated prevalence of 1:1,000,000. It is an autosomal recessive disease resulting from mutations in any of the 3 genes that encode the 3 polypeptide chains of fibrinogen and are located on the long arm of chromosome 4. Spontaneous bleeding, bleeding after minor trauma and excessive bleeding during interventional procedures are the principal manifestations. We review the management of afibrinogenemia. Replacement therapy is the mainstay of treatment of bleeding episodes in these patients and plasma-derived fibrinogen concentrate is the agent of choice. Cryoprecipitate and fresh frozen plasma are alternative treatments that should be used only when fibrinogen concentrate is not available. Secondary prophylactic treatment may be considered after life-threatening bleeding whereas primary prophylactic treatment is not currently recommended. We also discuss alternative treatment options and the management of surgery, pregnancy and thrombosis in these patients. The development of new tests to identify higher risk patients and of safer replacement therapy will improve the management of afibrinogenemia in the future.

Treatment of congenital fibrinogen disorders

BACKGROUND

The goal of the coagulation pathway is the conversion of fibrinogen to fibrin and formation of an insoluble clot. Although relatively rare, congenital fibrinogen disorders are interesting and pose several challenges that can serve as paradigms for many diseases. An impressive body of knowledge has accumulated recently, particularly thanks to international collaborative clinical and genetic studies allowing the molecular characterization of these disorders. However, apart from the possibility of developing safer fibrinogen concentrates and the availability of prenatal diagnosis, the basic therapeutic approach has changed little.

OBJECTIVE

We need to better understand the clinical phenotype of patients in order to administer fibrinogen preparations or other treatments more appropriately.

METHODS

We discuss current therapeutic options and others that could be available in the near future.

RESULTS/CONCLUSION

Patients with congenital fibrinogen deficiencies require better predictive tests for clinical complications and more efficient and available fibrinogen concentrates. Global hemostasis tests in combination with routine assays could help to individually tailor therapeutic protocols.