Generation of neutrophil extracellular traps in patients with acute liver failure is associated with poor outcome

BACKGROUND AND AIMS

Acute liver failure (ALF) is characterized by significant changes in the hemostatic system and by systemic inflammation. The formation of neutrophil extracellular traps (NETs), in which an activated neutrophil expels its DNA, histones, and granular enzymes, such as myeloperoxidase (MPO), has been associated with immune-mediated and thrombotic diseases. We hypothesized that formation of NETs in patients with ALF contributes to progression of disease.

APPROACH AND RESULTS

A total of 676 patients with ALF (international normalized ratio [INR], ≥1.5) or severe acute liver injury (ALI; INR, ≥2.0) were recruited from the U.S. ALF Study Group Registry between 2011 and 2018, of whom 308 patients (45.6%) had acetaminophen-induced ALF. Up to 21 days after admission, 483 patients (71.5%) survived without liver transplantation (LT). Levels of cell-free DNA (cfDNA) and the specific NET marker MPO-DNA complexes were measured in plasma samples obtained on admission and compared to levels in healthy controls. In addition, liver tissue obtained at transplantation of 20 ALF patients was stained for NETs. Levels of cfDNA were 7.1-fold, and MPO-DNA complexes 2.5-fold, higher in patients with ALF compared to healthy controls. cfDNA levels were not associated with 21-day transplant-free survival, but were higher in those patients with more-severe disease on admission, as reflected by various laboratory and clinical parameters. MPO-DNA levels were 30% higher in patients with ALF who died or required urgent LT. Liver tissue of ALF patients stained positive for NETs in 12 of 18 evaluable patients.

CONCLUSIONS

Here, we provide evidence for NET formation in patients with ALF. Elevated plasma levels of MPO-DNA complexes in patients with ALF were associated with poor outcome, which suggests that NET formation contributes to disease progression.

Primary Hemostatic Disorders and Late Major Bleeding After Transcatheter Aortic Valve Replacement

BACKGROUND

Periprocedural and late (>30 days) bleedings represent major complications after transcatheter aortic valve replacement and have been identified as potential areas for improved patient care.

OBJECTIVES

The authors sought to evaluate the impact of ongoing primary hemostasis disorders on late major/life-threatening bleeding complications (MLBCs).

METHODS

Bleedings were assessed according to the VARC-2 (Valve Academic Research Consortium-2) criteria. Closure time of adenosine diphosphate (CT-ADP), a surrogate marker of high molecular weight von Willebrand multimers proteolysis was assessed 24 h after the procedure. Ongoing primary hemostasis disorder was defined by a CT-ADP >180 s.

RESULTS

Among 372 patients who survived at 30 days, MLBCs occurred in 42 patients (11.3%) at a median follow-up of 383 days (interquartile range: 188 to 574 days). MLBCs were mainly of gastrointestinal origin (42.8%) and were associated with increased overall mortality (hazard ratio [HR]: 5.66; 95% confidence interval [CI]: 3.10 to 10.31; p < 0.001) and cardiac mortality (HR: 11.62; 95% CI: 4.59 to 29.37; p < 0.001). A 2.5-fold elevation of MLBCs could be evidenced in patients with a CT-ADP > 180 s (27.4% vs. 11.5%; p < 0.001). Multivariate regression analysis identified paravalvular leak (PVL) (HR: 6.31; 95% CI: 3.43 to 11.60; p < 0.0001) and CT-ADP > 180 s (HR: 3.08; 95% CI: 1.62 to 5.81; p = 0.0005) as predictor of MLBCs.

CONCLUSIONS

MLBCs after transcatheter aortic valve replacement are frequent and associated with an increased morbidity and mortality. PVL and CT-ADP >180 s were identified as strong predictors for MLBCs. These findings strongly suggest that persistent HMW defects contribute to enhanced bleeding risk in patients with residual PVL.

Perioperative standards for the treatment of coagulation disorders and usage of blood products in patients undergoing liver transplantation used in the Clinic for Transplant Surgery in Wrocław

BACKGROUND

Coagulation system disorders in liver transplantation (ltx) patients are considered a serious issue. Liver cirrhosis leads to decreased synthesis of clotting factors and decreased elimination of waste products, including coagulation proteins. Platelet sequestration and dysfunction in an enlarged spleen additionally worsen these conditions. The resulting state, the most common pathology of the coagulation system, involves the reduction of clotting potential and hyperfibrinolysis.

OBJECTIVES

Tackling the problem of impaired hemostasis is a dynamic process. Throughout the whole procedure, consisting of the preanhepatic, the anhepatic and the neohepatic phases, consecutive pathomechanisms disrupt the very balance that anesthesia aims to preserve.

MATERIAL AND METHODS

Rotational thromboelastometry (ROTEM), having been introduced in the Clinic of Anesthesiology and Intensive Therapy, Wroclaw Medical University, Poland, enables the efficient and early diagnosis of clotting disorders. An additional major problem which occurs during ltx, namely blood loss, could be solved using a cell separator.

RESULTS

In this study, we present the standards introduced to the Transplantology Department of the Vascular Surgery Clinic, Wroclaw Medical University, Poland, that describe blood treatment during ltx procedures.

CONCLUSIONS

We conclude that thromboelastometric examination and the use of a cell separator have significantly increased the safety of ltx procedures at our clinic. The introduction of thromboelastometry (TEM) and the implementation of the cell separator recovery method have enabled us to perform the dangerous and complicated surgical procedure of ltx in a much more stable and much safer manner than in the past.

[The thromboelastometric criteria of hemostasis disorders correction during liver transplantation]

The purpose of the study. Optimum correction of hemostasis remains one of the unsolved problems in anesthesia maintenance during liver transplantation. Modern methods of coagulation monitoring (thromboelastography, thromboelastometry) allows to differ the increased bleeding reason. The clear criteria for the appointment of the blood components according to these methods have not developed so far. The aim of this study was to determine the criteria of hemostasis disorders correction during liver transplantation.

MATERIALS AND METHODS

The study included all patients undergoing a liver transplantation in our clinic from January 2009 to December 2010. In certain intervals of time an intake of blood samples for the hemostasis study including koagulogramm, determination of the clotting factors and natural anticoagulants activity was performed.

RESULTS

There is no significant correlation between the results of the standard coagulation tests and thromboelastometry Based on the international hemostasis correction recommendations, with the help of ROC-analysis the search for thromboelastometry data, which would have pointed to the need for this therapy was made. Concerning coagulation factors deficiency (INR>2, APTT> 1.5) CT-EXTEM>80 has a sensitivity of 17% and a specificity of 97%, and CT-INTEM>240 has sensitivity of 51% and specificity of 96%. Use of A10-FIBTEM for fibrinogen deficiency diagnosis, A10-FIBTEM <9 has sensitivity of 95% and specificity of 63%. A simultaneous increase of CT-EXTEM >80 and CT-INTEM more than 300 has a sensitivity of 96% and a specificity 81% in relation to diagnose thrombocytopenia (platelet count less than 50,000 per mcl).

CONCLUSION

Correction of coagulation factors deficiency indicated when CT-EXTEM>80 and CT-INTEM> 240, hypofibrinogenemia when A10-FIBTEM <9, thrombocytopenia when of CT-EXTEM >80 and CT-INTEM increase simultaneously more than 300.

[Hemostatic disorders caused by chronic use of valproic acid in neurosurgical patients. Thromboelastographic monitoring]

The paper gives the results of analyzing the hemostatic system in 26 patients with various neurosurgical diseases on the basis of routine laboratory biochemical tests and thromboelastographic indicators. In all the patients, the pattern of the disease contained an epilepsy syndrome that required mono- or combination therapy with valproic acid. Laboratory indicators of clinical hypocoagulation were found to develop during the use of valproic acid, and its monotherapy in particular. Hemorrhagic complications were also analyzed in not only the immediate, but also late postoperative period (for as long as 6 months after surgery). Two cases of severe late complications, such as formation of chronic subdural hematomas requiring surgical intervention, were diagnosed in the valproate monotherapy group. A tactic using a thromboelastographic technique is proposed to prepare these patients for further neurosurgical intervention.

[The choice of surgical tactics in patients with unstable hemostasis and gastroduodenal ulcer bleeding]

Treatment results of 476 patients with acute gastroduodenal ulcer bleeding were analyzed. Men comprised 75% (n=357), women - 25% (n=119). All patients were divided in two groups. Treatment principles of patients of the first group (36.8%; n=175) were based on active conservative treatment. Surgery was performed in 70.3%, postoperative lethality comprised 12.2%, overall mortality was 9.7%. Second group consisted of 301 patients (63.2%). Individual based active surgical treatment was performed, including clinical and endoscopic evaluation of local hemostasis, prognostic criteria of bleeding recurrence, differential approach in time, extent and method of the applied surgery. Operative treatment was used in 81.1% of patients of the second group, postoperative lethality comprised 9.8%, overall mortality was 8.0%. Emergency operations were performed in 43.6% (n=160) of all patients, early elective surgery in 56.4% (n=207). Postoperative lethality comprised 10.6%, overall mortality rate was 8.6%. Therefore, individual based active surgical treatment proved to be preferable. Gastric resection showed to be more advisable then organ-preserving operations, considering emergency ulcer surgery.

[A new look at platelets and microparticles, including their role in haemostatic disorders and progression of neoplastic disease]

Platelets (PLT) are the smallest yet highly reactive components of the circulatory system. Microvesicles (platelet-derived microvesicles - PMV), also known as microparticles or microplatelets (platelet-derived microparticles - PMP), are released from platelets upon stimulation by thrombin, collagen or others platelet agonists. Both PLT and PMP play a role in haemostasis and mediate signal transmission between cells, especially cancer cells, thus modulating their functions. Moreover, these two platelet populations participate in transcellular exchange of information, affect immune responses and angiogenesis, which may facilitate tumour growth and development of distant metastases. Their role in tumour progression has been recognized, but the mechanism of their action remains still unclear. Assessment of PMP as a diagnostic and prognostic marker in various disorders is currently a subject of intense investigation.

[Disturbances of primary hemostasis in patients with dilation cardiomyopathy]

We studied morphological characteristics of platelets and parameters of platelet aggregation in patients with dilation cardiomyopathy. Augmented aggregatory activity of platelets was found in 76% of patients. In blood of majority of patients we found circulating leukocyte-platelet aggregates. This evidenced for development of inflammatory process and could be related to disturbances of blood rheology. In 2 patients examined by virusological method we revealed presence of a virus inside platelets. This phenomenon might serve as one of possible pathological pathways of disease progression at the account of spread of viral infection along vascular bed during thrombus formation.

[Preoperative identification of patients with impaired (primary) haemostasis. A practical concept]

The findings of a large prospective study designed to identify primary and/or secondary haemostatic disorders before surgical interventions are presented. A total of 5649 unselected adult patients were enrolled to identify impaired haemostasis before surgical interventions. Each patient was asked to answer a standardized questionnaire concerning bleeding history. Activated partial thromboplastin time (aPTT), prothrombin time (PT), and platelet counts (PC) including PFA-100 (platelet function analyzer): collagen-epinephrine (C/E), and collagen-ADP (C/ADP) were routinely done in all patients. Additional tests, bleeding time (BT), von Willebrand factor (VWF:Ag, VWF:Rcof) and a further haemostaseological diagnostic was performed only in patients with a positive bleeding history and/or evidence of impaired haemostasis; e.g., drug ingestion. The bleeding history was negative in 5021 patients (88.8%) but positive in the remaining 628 (11.2%). Impaired haemostasis could be verified only in 256 (40.8%) of these patients. The vast majority was identified with PFA-100: C/E (n = 250; 97.7%). The sensitivity of the PFA-100: collagen-epinephrine was the highest (90.8%) in comparison to the other screening tests (BT, aPTT, PT, VWF : Ag). The positive predictive value (to detection of impaired haemostasis) of the PFA-100: collagen-epinephrine with the standardized questionnaire was high (82%), but the negative predictive value was higher (93%). The use of a standardized questionnaire and, if indicated, the PFA-100: C/E and/or other specific tests not only ensure the detection of impaired haemostasis in almost every case but also a significant reduction of the costs. Based on these data, national regards are formulated or under construction.

[Coagulation analysis in transplantation patients]

In patients post organ transplantation, the underlying disorder necessitating the transplantation, as well as the transplantation itself, can both mask pre-existing haemostatic abnormalities or lead to them. Since the liver is the main production site for coagulation factors, orthotopic liver transplantation predestinates for acquiring or losing a genetically determined coagulation defect. In coagulation diagnostics, this may lead to a discrepancy between functional plasma tests and molecular biologic findings if these are gathered from nucleated cells of the peripheral blood, as is the standard. Due to the rareness of most defects and the lack of consequences in case of diagnosis of a more common coagulation disorder, no general screening before or after transplantation is required. Underlying diseases leading to liver transplantation as well as the actual transplantation must be considered when interpreting the findings.

[Endotoxin aggression in the development of hemostatic disorders in children with surgical diseases]

The role of endotoxin aggression in the development of hemostatic disorders was analyzed in 62 children who had undergone urgent and elective surgeries. It is demonstrated that indices of endotoxin-antiendotoxin system and hemostasis before surgery may be regarded as prognostic criteria for development of complications during and after surgery.

[Hemostatic coronary risk factors in a healthy population of Maracaibo, Venezuela]

The purpose of the present work was to determine the plasma concentrations of fibrinogen and Von Willebrand Factor (VWF) as well as platelet aggregation, in an apparently healthy population of 306 men and 41 women, 33 to 65 years of age, workers of the national oil industry (PDVSA, Maracaibo), as a base investigation in a 5-year prospective national collaborative study. The participants were previously subjected to a thorough clinical examination with cardiovascular evaluation and laboratory tests. Clottable fibrinogen and VWF concentrations were determined in platelet poor plasma, the last one by immunoclectrophoresis, and a multimeric analysis of VWF was performed on those plasmas with concentrations higher than 150 U/dL by SDS agarose electrophoresis, followed by cellulose membrane transference. Platelet aggregation was studied in platelet rich plasma with no addition of stimulants and after collagen and ristocetin were added. Forty per cent of men and 65.8% of women, showed fibrinogen concentrations above 300 mg/dL (p < 0.01) and 12.2% of men and 15.4% of women had VWF values higher than 150 U/dL, with normal multimeric distribution. Fourteen individuals presented spontancous platelet aggregation and increased aggregation in 12 and 13 of them, after induction with collagen and ristocetin respectively. Comparing these findings with those of previous collaborative studies from other countries, the present results could mean that an important proportion of the population here studied, could be at risk for a future coronary event; however, as these are the base findings in Maracaibo, the significance of our results will be better evaluated at the end of the five year study.

[Pathogenesis of disturbances of the hemostatic system in neonates]

Described in the paper are chief pathogenetic mechanisms of development of disturbances in the hemostasis system in neonates born to mothers presenting with extragenital pathologies. Marked clotting changes were noted together with those in the system of the erythron. Recordable in the above infants were also vascular permeability disorders, abnormalities of metabolism. These changes were especially manifest in those children presenting with diabetic fetopathy and in babies born to mothers with neurocirculatory asthenia. The results secured permitted the development of the system of curative-and-prophylactic measures to be instituted in the above infants.

Haemostatic abnormalities, cardiac involvement and serum tumor necrosis factor levels in X-linked dystrophic patients

Left ventricular thrombosis and systemic emboli have been demonstrated to complicate cardiomyopathy in Duchenne and Becker muscular dystrophy (DMD, BMD). We investigated plasma levels of prothrombin fragment 1+2 (F1+2). thrombin-antithrombin III complex (TAT) and circulating levels of tumor necrosis factor-alpha (TNF-alpha), a procoagulant cytokine that has been shown to be elevated in patients with depressed cardiac function, in 20 patients with DMD and 12 patients with BMD as compared with 30 age-matched control subjects. Significantly elevated levels of F1+2 (DMD: 1.4+/-0.8 nmol/l; BMD: 1.8+/-0.8 nmol/l vs. controls: 0.7+/-0.2 nmol/l, p <0.01 and p <0.001, respectively), TAT complexes (DMD: 4.7+/-2.7 microg/l, BMD: 5+/-2.3 microg/l vs. controls: 1.6+/-0.5 microg/l, p <0.001) and TNF-alpha (54+/-9 vs. 25+/-7 pg/ml, p <0.001) were observed in patients with the dystrophic disease compared to control subjects. A significantly negative correlation was also found between F1+2 and TAT complexes and left ventricular ejection fraction (r = -0.65, p <0.0001; r = -0.80, p < 0.0001, respectively) and a positive correlation between F1+2 and TAT complexes and serum TNF-alpha levels (r = 0.67, p <0.0001; r = 0.70, p <0.0001, respectively). Our results indicate a hypercoagulable state in X-linked dystrophic patients. A possible relationship between haemostatic activation, left ventricular dysfunction and TNF-alpha system upregulation may be suggested.