Antithrombin III (ATIII) replacement therapy in patients with sepsis and/or postsurgical complications: a controlled double-blind, randomized, multicenter study

Efficacy of antithrombin administration for patients with sepsis: A systematic review, meta-analysis, and meta-regression

Aims

There have been inconsistent reports regarding the effect of antithrombin on sepsis; furthermore, there are limited reports on how dosage affects therapeutic efficacy. Thus, we aimed to perform a systematic review and meta-analysis of the use of antithrombin for sepsis and a meta-regression analysis of antithrombin dosage.

Methods

We included randomized controlled trials (RCTs) and observational studies of adult patients with sepsis who received antithrombin. Outcomes included all-cause mortality and serious bleeding complications. Statistical analyses and data synthesis were performed using a random-effects model; further, meta-regression and funnel plots were used to explore heterogeneity and biases.

Results

Seven RCTs and six observational studies were included. Most patients in the RCTs and observational studies had severe sepsis and septic-disseminated intravascular coagulation (DIC), respectively. A meta-analysis using RCTs showed no significant differences in mortality between the antithrombin and control groups. However, the meta-analysis of observational studies indicated a trend of decreasing mortality rates with antithrombin administration (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.68-0.92; p = 0.002). Bleeding complications were significantly higher in the antithrombin group than in the control group in both study types (OR, 1.90; 95% CI, 1.52-2.37; p < 0.01). The meta-regression analysis showed no correlation between antithrombin dosage and mortality.

Conclusion

A meta-analysis of RCTs confirmed no survival benefit of antithrombin, whereas that of observational studies, which mostly focused on septic DIC, showed a significant beneficial effect on improving outcomes. Indications of antithrombin should be considered based on its beneficial and harmful effects.

The effect of antithrombotic treatment on mortality in patients with acute infection: A meta-analysis of randomized clinical trials

BACKGROUND AND AIMS

Acute infections cause relevant activation of innate immunity and inflammatory cascade. An excessive response against pathogens has been proved to trigger the pathophysiological process of thrombo-inflammation. Nevertheless, an association between the use of antithrombotic agents and the outcome of critically ill patients with infectious diseases is lacking. The aim of this meta-analysis is to determine the impact of antithrombotic treatment on survival of patients with acute infective disease.

METHODS

MEDLINE, Embase, Cinahl, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) databases were systematically searched from inception to March 2021. We included randomized controlled trials (RCTs) that evaluated any antithrombotic agent in patients with infectious diseases other than COVID-19. Two authors independently performed study selection, data extraction and risk of bias evaluation. The primary outcome was all-cause mortality. Summary estimates for mortality were calculated using the inverse-variance random-effects method.

RESULTS

A total of 16,588 patients participating in 18 RCTs were included, of whom 2141 died. Four trials evaluated therapeutic-dose anticoagulation, 1 trial prophylactic-dose anticoagulation, 4 trials aspirin, and 9 trials other antithrombotic agents. Overall, the use of antithrombotic agents was not associated with all-cause mortality (relative risk 0.96; 95% confidence interval, 0.90-1.03).

CONCLUSIONS

The use of antithrombotics is not associated with all-cause mortality in patients with infectious disease other than COVID-19. Complex pathophysiological interplays between inflammatory and thrombotic pathways may explain these results and need further investigation.

REGISTRATION

PROSPERO, CRD42021241182.

Anticoagulant therapies against sepsis-induced disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is a frequent but lethal complication in sepsis. Anticoagulant therapies, such as heparin, antithrombin, activated protein C, and recombinant human-soluble thrombomodulin, were expected to regulate the progression of coagulopathy in sepsis. Although a number of randomized controlled trials (RCTs) have evaluated the survival effects of these therapies over the past few decades, there remains no consistent evidence showing a significant survival benefit of anticoagulant therapies. Currently, anticoagulant therapies are not conducted as a standard treatment against sepsis in many countries and regions. However, most of these RCTs were performed overall in patients with sepsis but not in those with sepsis-induced DIC, who were theoretically the optimal target population of anticoagulants. Actually, multiple lines of evidence from observational studies and meta-analyses of the RCTs have suggested that anticoagulant therapies might reduce mortality only when used in septic DIC. In addition, the severity of illness is another essential factor that maximally affects the efficacy of the therapy. Therefore, to provide evidence on the true effect of anticoagulant therapies, the next RCTs must be designed to enroll only patients with sepsis-induced overt DIC and a high severity of illness. To prepare these future RCTs, a novel scientific infrastructure for accurate detection of patients who can receive maximal benefit from anticoagulant therapies also needs to be established.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

The Roles of Coagulation Disorder and Microthrombosis in Sepsis: Pathophysiology, Diagnosis, and Treatment

The diagnostic criteria of overt disseminated intravascular coagulation (DIC) were established by the International Society on Thrombosis and Haemostasis (ISTH) in 2001. Since then, DIC has long been associated with adverse outcomes. However, recent advances in sepsis shed light on the role of coagulation disorders in the progression of sepsis. Currently, inflammation and coagulation are recognized as the two drivers that promote organ dysfunction in sepsis and septic shock. The ISTH has published new diagnostic criteria for improved management, namely sepsis-induced coagulopathy (SIC), in 2017. SIC is a pragmatic scoring system composed of platelet count, prothrombin time, and organ dysfunction score to detect the early-stage of sepsis-associated DIC. Since overt DIC represents an uncompensated coagulation disorder, a two-step approach using SIC and overt DIC criteria is a novel strategy to evaluate the severity and manage this challenging complication. Although there is no globally agreed on anticoagulant therapy for DIC, the Japanese Surviving Sepsis Campaign Guidelines 2020 recommend using antithrombin and recombinant thrombomodulin for sepsis associated DIC. Since research in this area has been previously reported, an international collaborative study is necessary to develop future diagnostic tools and treatment strategies.

Understanding the andromeda strain - The role of cytokine release, coagulopathy and antithrombin III in SARS-CoV2 critical illness

As the current coronavirus pandemic continues and cases of COVID-19 critical illness rise, physicians and scientists across the globe are working to understand and study its pathophysiology. Part of the pathology of this illness may result from its prothrombotic potential as witnessed from derangements in coagulation and thrombotic complications reported in observational studies performed in China and Europe to findings of microthrombosis upon autopsy analysis of patients who succumbed to COVID-19. Multiple organizations, including the American Society of Hematology (ASH), recommend the routine use of prophylactic heparin to temper the thrombotic complications of this illness given its mortality benefit in severe COVID-19 infections. Reductions in circulating levels of Antithrombin III (AT), the primary mediator of heparin's action, is present in cases of coronavirus related critical illness. AT's use as a prognostic marker, an important effector of heparin resistance, and a potential therapeutic target for COVID-19 remains to be explored.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Disseminated Intravascular Coagulation: An Update on Pathogenesis, Diagnosis, and Therapeutic Strategies

Disseminated intravascular coagulation (DIC) is an acquired clinicobiological syndrome characterized by widespread activation of coagulation leading to fibrin deposition in the vasculature, organ dysfunction, consumption of clotting factors and platelets, and life-threatening hemorrhage. Disseminated intravascular coagulation is provoked by several underlying disorders (sepsis, cancer, trauma, and pregnancy complicated with eclampsia or other calamities). Treatment of the underlying disease and elimination of the trigger mechanism are the cornerstone therapeutic approaches. Therapeutic strategies specific for DIC aim to control activation of blood coagulation and bleeding risk. The clinical trials using DIC as entry criterion are limited. Large randomized, phase III clinical trials have investigated the efficacy of antithrombin (AT), activated protein C (APC), tissue factor pathway inhibitor (TFPI), and thrombomodulin (TM) in patients with sepsis, but the diagnosis of DIC was not part of the inclusion criteria. Treatment with APC reduced 28-day mortality of patients with severe sepsis, including patients retrospectively assigned to a subgroup with sepsis-associated DIC. Treatment with APC did not have any positive effects in other patient groups. The APC treatment increased the bleeding risk in patients with sepsis, which led to the withdrawal of this drug from the market. Treatment with AT failed to reduce 28-day mortality in patients with severe sepsis, but a retrospective subgroup analysis suggested possible efficacy in patients with DIC. Clinical studies with recombinant TFPI or TM have been carried out showing promising results. The efficacy and safety of other anticoagulants (ie, unfractionated heparin, low-molecular-weight heparin) or transfusion of platelet concentrates or clotting factor concentrates have not been objectively assessed.

Antithrombin deficiency is associated with mortality and impaired organ function in septic pediatric patients: a retrospective study

Background

Sepsis remains a major problem in intensive care medicine. It is often accompanied by coagulopathies, leading to thrombotic occlusion of small vessels with subsequent organ damage and even fatal multi-organ failure. Prediction of the clinical course and outcome—especially in the heterogeneous group of pediatric patients—is difficult. Antithrombin, as an endogenous anticoagulant enzyme with anti-inflammatory properties, plays a central role in controling coagulation and infections. We investigated the relationship between antithrombin levels and organ failure as well as mortality in pediatric patients with sepsis.

Methods

Data from 164 patients under the age of 18, diagnosed with sepsis, were retrospectively reviewed. Antithrombin levels were recorded three days before to three days after peak C-reactive protein to correlate antithrombin levels with inflammatory activity. Using the concept of developmental haemostasis, patients were divided into groups <1 yr and ≥1 yr of age.

Results

In both age groups, survivors had significantly higher levels of antithrombin than did deceased patients. An optimal threshold level for antithrombin was calculated by ROC analysis for survival: 41.5% (<1 yr) and 67.5% (≥1 yr). The mortality rate above this level was 3.3% (<1 yr) and 9.5% (≥1 yr), and below this level 41.7% (<1 yr) and 32.2% (≥1 yr); OR 18.8 (1.74 to 1005.02), p = 0.0047, and OR 4.46 (1.54 to 14.89), p = 0.003. In children <1 yr with antithrombin levels <41.5% the rate of respiratory failure (66.7%) was significantly higher than in patients with antithrombin levels above this threshold level (23.3%), OR 6.23 (1.23 to 37.81), p = 0.0132. In children ≥1 yr, both liver failure (20.3% vs 1.6%, OR 15.55 (2.16 to 685.01), p = 0.0008) and a dysfunctional intestinal tract (16.9% vs 4.8%, OR 4.04 (0.97 to 24.08), p = 0.0395) occurred more frequently above the antithrombin threshold level of 67.5%.

Conclusion

In pediatric septic patients, significantly increased mortality and levels of organ failure were found below an age-dependent antithrombin threshold level. Antithrombin could be useful as a prognostic marker for survival and occurrence of organ failure in pediatric sepsis.

Optimal Antithrombin Activity Threshold for Initiating Antithrombin Supplementation in Patients With Sepsis-Induced Disseminated Intravascular Coagulation: A Multicenter Retrospective Observational Study

Low-dose antithrombin supplementation therapy (1500 IU/d for 3 days) improves outcomes in patients with sepsis-induced disseminated intravascular coagulation (DIC). This retrospective study evaluated the optimal antithrombin activity threshold to initiate supplementation, and the effects of supplementation therapy in 1033 patients with sepsis-induced DIC whose antithrombin activity levels were measured upon admission to 42 intensive care units across Japan. Of the 509 patients who had received antithrombin supplementation therapy, in-hospital mortality was significantly reduced only in patients with very low antithrombin activity (≤43%; bottom quartile; adjusted hazard ratio: 0.603; 95% confidence interval: 0.368-0.988; P = .045). Similar associations were not observed in patients with low, moderate, or normal antithrombin activity levels. Supplementation therapy did not correlate with the incidence of bleeding requiring transfusion. The adjusted hazard ratios for in-hospital mortality increased gradually with antithrombin activity only when initial activity levels were very low to normal but plateaued thereafter. We conclude that antithrombin supplementation therapy in patients with sepsis-induced DIC and very low antithrombin activity may improve survival without increasing the risk of bleeding.

A summary of the Japan septic disseminated intravascular coagulation study

Over the past few decades, the large, international, randomized controlled trials of anticoagulant therapies for patients with sepsis have not yielded any improvement in mortality rates. However, in Japan, anticoagulant therapies are administered for sepsis patients with disseminated intravascular coagulation (DIC), but not for sepsis patients without DIC. Furthermore, epidemiological data regarding sepsis in Japan are scarce. Therefore, a nationwide multicenter retrospective observational study, the Japan Septic Disseminated Intravascular Coagulation (JSEPTIC DIC) study, was undertaken. The JSEPTIC DIC study enrolled 42 intensive care units and included 3,195 patients with sepsis. The results of the JSEPTIC DIC study indicated the following: (i) anticoagulant therapy may be effective in sepsis-induced DIC patients at high risk for death, (ii) recombinant human soluble thrombomodulin administration and antithrombin supplementation are associated with survival benefits in patients with sepsis-induced DIC.

Management of disseminated intravascular coagulation: current insights on antithrombin and thrombomodulin treatments

Sepsis and septic shock are frequently complicated by disseminated intravascular coagulation (DIC), which decreases the survival rate of patients with sepsis. In the past, large international randomized controlled trials (RCTs) using physiological anticoagulants for sepsis-induced DIC were not performed; however, RCTs have been conducted for sepsis and/or septic shock. In these trials, physiological anticoagulants did not show any beneficial effects compared with placebo for the treatment of sepsis and/or septic shock. In Japan, DIC treatments using antithrombin (AT) and/or recombinant human soluble thrombomodulin (rhTM) are common for patients with sepsis-induced DIC. Recently, large propensity score analyses demonstrated that AT and rhTM improved survival in patients with sepsis-induced DIC. Furthermore, post hoc analyses and meta-analyses that selected patients with sepsis-induced DIC from the previous large international RCTs indicated that physiological anticoagulants improved survival without increasing the associated sepsis-induced DIC bleeding. DIC treatments, such as AT and rhTM, may demonstrate beneficial effects when they are targeted at patients with sepsis-induced DIC only.

Clinically-oriented therapies in sepsis: a review

Our insight of the sepsis response has evolved to encompass not only the pro-inflammatory but also an anti-inflammatory reaction following infection. Clinical trials have been designed to target either bacterial products, endotoxin in particular, or mediators involved in the sepsis response, but until recently the majority of them have given unfavorable results. In this article, we provide a scope of clinical trials that have been done in immunomodulation during sepsis whether or not they provide positive results. We will also discuss some of the reasons why those studies have been disappointing. Current and future trials with a better assessment of inflammatory status of patients and better-defined outcomes such as organ dysfunction are now underway.

Disseminated Intravascular Coagulopathy (DIC): Pathophysiology, Laboratory Diagnosis, and Management

Disease entities such as sepsis, shock, obstetric complications, and neoplasms share the process of disseminated intravascular coagulopathy (DIC) as a secondary complication. Regardless of the initiating event, DIC results from the activation of the virtually unregulated coagulation cascade, characterized by the generation of thrombin with fibrin deposition within the micro- and macrovascular systems (i.e., multiple thrombi), combined with a hemorrhagic diathesis. The counteraction by the fibrinolytic cascade is variable and is characterized by the conversion of plasminogen to plasmin, the latter functioning as a potent proteolytic enzyme, capable of degrading fibrinogen, fibrin, and several clotting factors. The kinin and complement cascades also partake in the promotion of DIC. In addition, antithrombin (AT), proteins C and S, antiplasmin, and plasminogen activator inhibitor 1, play a functional role in curtailing the activation of the coagulation and fibrinolytic mechanisms, but they too may be affected by the DIC process, particularly because a marked decrease in AT takes place in severe cases.

The laboratory findings of DIC are as variable as the underlying clinical presentation and usually include elevation of D-dimer (a product of lysed fibrin), fibrinogen degradation products (FDP), as well as prolongation of prothrombin time (PT), partial thromboplastin time (PTT), and thrombin time, accompanied by thrombocytopenia and hypofibrinogenemia (noted mostly in obstetrical cases). Because some of these assays are not specific for the diagnosis of DIC, we propose the use of a new, simple, and cost effective panel: D-dimer, FDP, and AT. Elevations in FDP and D-dimer are sensitive for the diagnosis of DIC and a marked drop in AT establishes a poor prognosis.

Aside from the treatment of the underlying triggering event, a consensus with regard to the most effective management of DIC has not been established. Herein we summarize the rationale for the use of conventional therapeutic modalities such as fresh frozen plasma, cryoprecipitate, platelet and clotting factor concentrates, as well as the use of new alternatives. The use of AT infusions to maintain plasma levels of 150% of normal shows great promise in severe cases.

A fundamental understanding of the pathophysiology of DIC combined with an appreciation for efficient laboratory testing will allow for the most comprehensive diagnostic and therapeutic alternatives.

Sepsis and disseminated intravascular coagulation

Sepsis is frequently complicated by coagulopathy and, in about 35 % of severe cases, by disseminated intravascular coagulation (DIC). In Japan, aggressive treatment of septic DIC is encouraged using antithrombin and recombinant thrombomodulin. The macrophages, monocytes, and neutrophils are a source of TF and participate in the direct activation of the coagulation cascade in the early phases of sepsis. And activated factor X (FXa), which is involved in hemostasis, thrombogenesis, inflammation, and cellular immune responses, induces TF expression in human peripheral monocytes and, conversely, that inhibition of FXa activity reduces TF expression. Both inflammation and coagulation play an important role in DIC due to sepsis. In addition to inflammatory cytokines (TNF-α, IL-1 and so on), HMGB1 has recently been shown to mediate the lethal late phase of sepsis and caused coagulopathy. TM not only binds HMGB1 but also aids the proteolytic cleavage of HMGB1 by thrombin. There have been many reports of the efficacy of recombinant TM and antithrombin for treatment of septic DIC from Japan. Further investigation of the efficacy of recombinant TM and AT in countries other than Japan, as well as the monitoring of medical costs incurred during hospitalization, will help validate the use of TM and AT for treatment of septic DIC.

Efficacy and safety of anticoagulant therapy in three specific populations with sepsis: a meta-analysis of randomized controlled trials

ESSENTIALS: Most anticoagulant therapy has failed to demonstrate a survival benefit in the overall sepsis population. We conducted separate meta-analyses of anticoagulant therapy in three different populations. Survival benefit was observed only in the septic disseminated intravascular coagulation (DIC) population. Further randomized controlled trials should focus on specific populations with septic DIC.

SUMMARY

BACKGROUND

Although many preclinical trials have indicated the effectiveness and safety of anticoagulant therapy as an adjuvant therapy against sepsis, there is little evidence to support its effectiveness to reduce mortality in the overall population with sepsis in clinical situations. However, several studies suggested that specific anticoagulant therapy may potentially reduce mortality in patients with sepsis-induced disseminated intravascular coagulation (DIC).

OBJECTIVE

We investigated whether the survival benefit of anticoagulant therapy might pertain to the coagulopathic population with sepsis.

METHODS

We conducted separate meta-analyses of randomized controlled trials for anticoagulant therapy in three different populations: (i) overall population with sepsis, (ii) population with sepsis-induced coagulopathy, and (iii) population with sepsis-induced DIC. We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials comparing anticoagulant therapy with placebo or no intervention in sepsis patients. We measured all-cause mortality as the primary outcome and bleeding complications as the secondary outcome.

RESULTS

We analyzed 24 trials enrolling 14 767 patients. There were no significant reductions in mortality in the overall sepsis population and the population with sepsis-induced coagulopathy. Otherwise, we observed significant reductions in mortality (risk ratio 0.72, 95% confidence interval 0.62-0.85) in the population with sepsis-induced DIC. As adverse events, bleeding complications tended to increase similarly with anticoagulant therapy in all three populations.

CONCLUSION

Although associated with an increased risk of bleeding, anticoagulant therapy resulted in no survival benefits in the overall sepsis population and even the population with sepsis-induced coagulopathy; beneficial effects on mortality were observed only in the population with sepsis-induced DIC.

Antithrombin III for critically ill patients: a systematic review with meta-analysis and trial sequential analysis

Purpose

Antithrombin III (AT III) is an anticoagulant with anti-inflammatory properties. We assessed the benefits and harms of AT III in critically ill patients.

Methods

We searched from inception to 27 August 2015 in CENTRAL, MEDLINE, EMBASE, CAB, BIOSIS and CINAHL. We included randomized controlled trials (RCTs) irrespective of publication status, date of publication, blinding status, outcomes published or language.

Results

We included 30 RCTs with a total of 3933 participants. The majority of included trials were at high risk of bias. Combining all trials, regardless of bias, showed no statistically significant effect of AT III on mortality (RR 0.95, 95 % CI 0.88–1.03, I² = 0 %, fixed-effect model, 29 trials, 3882 participants). Among those with severe sepsis and disseminated intravascular coagulation (DIC), AT III showed no impact on mortality (RR 0.95, 95 % Cl 0.88–1.03, I² = 0 %, fixed-effect model, 12 trials, 2858 participants). We carried out multiple subgroup and sensitivity analyses to assess the benefits and harms of AT III and to examine the impact of risk of bias. AT III significantly increased bleeding events (RR 1.58, 95 % CI 1.35–1.84, I² = 0 %, fixed-effect model, 11 trials, 3019 participants). However, for all other outcome measures and analyses, the results did not reach statistical significance.

Conclusions

There is insufficient evidence to support AT III substitution in any category of critically ill participants including those with sepsis and DIC. AT III did not show an impact on mortality, but increased the risk of bleeding.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-016-4225-7) contains supplementary material, which is available to authorized users.

Antithrombin III for critically ill patients

BACKGROUND

Critical illness is associated with uncontrolled inflammation and vascular damage which can result in multiple organ failure and death. Antithrombin III (AT III) is an anticoagulant with anti-inflammatory properties but the efficacy and any harmful effects of AT III supplementation in critically ill patients are unknown. This review was published in 2008 and updated in 2015.

OBJECTIVES

To examine:1. The effect of AT III on mortality in critically ill participants.2. The benefits and harms of AT III.We investigated complications specific and not specific to the trial intervention, bleeding events, the effect on sepsis and disseminated intravascular coagulation (DIC) and the length of stay in the intensive care unit (ICU) and in hospital in general.

SEARCH METHODS

We searched the following databases from inception to 27 August 2015: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid SP), EMBASE (Ovid SP,), CAB, BIOSIS and CINAHL. We contacted the main authors of trials to ask for any missed, unreported or ongoing trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) irrespective of publication status, date of publication, blinding status, outcomes published, or language. We contacted the investigators and the trial authors in order to retrieve missing data. In this updated review we include trials only published as abstracts.

DATA COLLECTION AND ANALYSIS

Our primary outcome measure was mortality. Two authors each independently abstracted data and resolved any disagreements by discussion. We presented pooled estimates of the intervention effects on dichotomous outcomes as risk ratios (RR) with 95% confidence intervals (CI). We performed subgroup analyses to assess risk of bias, the effect of AT III in different populations (sepsis, trauma, obstetrics, and paediatrics), and the effect of AT III in patients with or without the use of concomitant heparin. We assessed the adequacy of the available number of participants and performed trial sequential analysis (TSA) to establish the implications for further research.

MAIN RESULTS

We included 30 RCTs with a total of 3933 participants (3882 in the primary outcome analyses).Combining all trials, regardless of bias, showed no statistically significant effect of AT III on mortality with a RR of 0.95 (95% CI 0.88 to 1.03), I² statistic = 0%, fixed-effect model, 29 trials, 3882 participants, moderate quality of evidence). For trials with low risk of bias the RR was 0.96 (95% Cl 0.88 to 1.04, I² statistic = 0%, fixed-effect model, 9 trials, 2915 participants) and for high risk of bias RR 0.94 (95% Cl 0.77 to 1.14, I² statistic = 0%, fixed-effect model, 20 trials, 967 participants).For participants with severe sepsis and DIC the RR for mortality was non-significant, 0.95 (95% Cl 0.88 to 1.03, I² statistic = 0%, fixed-effect model, 12 trials, 2858 participants, moderate quality of evidence).We conducted 14 subgroup and sensitivity analyses with respect to the different domains of risk of bias, but detected no statistically significant benefit in any subgroup analyses.Our secondary objective was to assess the benefits and harms of AT III. For complications specific to the trial intervention the RR was 1.26 (95% Cl 0.83 to 1.92, I² statistic = 0%, random-effect model, 3 trials, 2454 participants, very low quality of evidence). For complications not specific to the trial intervention, the RR was 0.71 (95% Cl 0.08 to 6.11, I² statistic = 28%, random-effects model, 2 trials, 65 participants, very low quality of evidence). For complications other than bleeding, the RR was 0.72 ( 95% Cl 0.42 to 1.25, I² statistic = 0%, fixed-effect model, 3 trials, 187 participants, very low quality of evidence). Eleven trials investigated bleeding events and we found a statistically significant increase, RR 1.58 (95% CI 1.35 to 1.84, I² statistic = 0%, fixed-effect model, 11 trials, 3019 participants, moderate quality of evidence) in the AT III group. The amount of red blood cells administered had a mean difference (MD) of 138.49 (95% Cl -391.35 to 668.34, I² statistic = 84%, random-effect model, 4 trials, 137 participants, very low quality of evidence). The effect of AT III in patients with multiple organ failure (MOF) was a MD of -1.24 (95% Cl -2.18 to -0.29, I² statistic = 48%, random-effects model, 3 trials, 156 participants, very low quality of evidence) and for patients with an Acute Physiology and Chronic Health Evaluation score (APACHE) at II and III the MD was -2.18 (95% Cl -4.36 to -0.00, I² statistic = 0%, fixed-effect model, 3 trials, 102 participants, very low quality of evidence). The incidence of respiratory failure had a RR of 0.93 (95% Cl 0.76 to 1.14, I² statistic = 32%, random-effects model, 6 trials, 2591 participants, moderate quality of evidence). AT III had no statistically significant impact on the duration of mechanical ventilation (MD 2.20 days, 95% Cl -1.21 to 5.60, I² statistic = 0%, fixed-effect model, 3 trials, 190 participants, very low quality of evidence); on the length of stay in the ICU (MD 0.24, 95% Cl -1.34 to 1.83, I² statistic = 0%, fixed-effect model, 7 trials, 376 participants, very low quality of evidence) or on the length of stay in hospital in general (MD 1.10, 95% Cl -7.16 to 9.36), I² statistic = 74%, 4 trials, 202 participants, very low quality of evidence).

AUTHORS' CONCLUSIONS

There is insufficient evidence to support AT III substitution in any category of critically ill participants including the subset of patients with sepsis and DIC. We did not find a statistically significant effect of AT III on mortality, but AT III increased the risk of bleeding events. Subgroup analyses performed according to duration of intervention, length of follow-up, different patient groups, and use of adjuvant heparin did not show differences in the estimates of intervention effects. The majority of included trials were at high risk of bias (GRADE; very low quality of evidence for most of the analyses). Hence a large RCT of AT III is needed, without adjuvant heparin among critically ill patients such as those with severe sepsis and DIC, with prespecified inclusion criteria and good bias protection.

Analysis of the influence of antithrombin on microvascular thrombosis: anti-inflammation is crucial for anticoagulation

Purpose

Microvascular thrombosis during septic conditions is of essential clinical relevance, but the pathomechanisms are not yet completely understood. The purpose of this study was to study the distinguished differentiation of the interactions of inflammation and coagulation using antithrombin (AT), a mediator of anticoagulation and anti-inflammation.

Methods

Using a thrombosis model in a cremaster muscle preparation of male C57Bl/6J mice (n = 83), we quantitatively assessed microvascular thrombus formation by using intravital fluorescence microscopy. Experimental groups consisted of animals treated with AT or with tryptophan⁴⁹-blocked AT (TrypAT), which exerts only anticoagulant but no anti-inflammatory effects. To further see whether endothelial glycosaminoglycan (GAG) binding with consecutive prostacyclin (PGI₂) release is mandatory for the anticoagulant process of AT, animals were administered heparin or indomethacin either alone or in combination with AT.

Results

The antithrombotic capacity of AT significantly differs in the experimental groups in which anti-inflammation was antagonized. This is given by the significantly prolonged occlusion times (p < 0.05) and higher patency rates in case of application of AT alone; while all other groups in which the anti-inflammatory action of AT was blocked by TrypAT, heparin or indomethacin revealed thrombus kinetics comparable to controls.

Conclusions

The anti-inflammatory influence of AT is essentially linked to its anticoagulant effect in the microvascular system. Those specifications of the active profile of AT characterize the intimate interactions of the anticoagulant and anti-inflammatory pathways. This might be of relevance for AT as a therapeutic agent in critically diseased patients and the clinical understanding of microvascular thrombosis.

Impact of withdrawing antithrombin III administration from management of septic patients with or without disseminated intravascular coagulation

Antithrombin III (ATIII) of low doses (1500-3000 units per day for 3-5 days) has been used for treatment of disseminated intravascular coagulation (DIC) for decades in Japan. In this study, we have examined the impact of ATIII practice change on outcome in critically ill patients with sepsis and DIC. From April 2005 to September 2008, all septic patients admitted to our ICU were divided into two groups: before withdrawing ATIII (period 1) and after withdrawing ATIII (period 2). Patients treated with ATIII in the period 1 and those not treated with ATIII in the period 2 were then matched according to the similar Acute Physiology and Chronic Health Evaluation II scores (± 3) and the same diagnosis grouping. Sensitivity analysis was also conducted for patients with DIC. Forty-one out of 98 patients (41.8%) in the period 1 and only one out of 80 patients (1.3%) in the period 2 were treated with ATIII. Thirty pairs of the patients were matched. There was no difference between the two groups regarding the platelet counts and Sepsis-related Organ Failure Assessment scores at day 1 and day 4. A subgroup analysis was conducted with 12 patients diagnosed with DIC out of the 30 pairs. There was no difference between the two DIC groups for platelet counts, Sepsis-related organ failure assessment scores and DIC score at day 1 and also day 4. Although not significant, hospital mortality tended lower in the period 2. This study found that withdrawing ATIII administration from management of septic patients with or without DIC did not influence outcome.

Use of recombinant human soluble thrombomodulin in patients with sepsis-induced disseminated intravascular coagulation after intestinal perforation

BACKGROUND

Anticoagulant therapy has been evaluated with respect to its potential usefulness in reducing the high mortality rates associated with severe sepsis, including sepsis-induced disseminated intravascular coagulation (DIC) after intestinal perforation. We examined the hypothesis that recombinant human soluble thrombomodulin (rhTM) is effective in the treatment of patients with septic shock with sepsis-induced DIC after laparotomy for intestinal perforation.

METHODS

We performed propensity-score and instrumental variable analyses of the Japanese Diagnosis Procedure Combination in-patient database, a nationwide administrative database. The main outcome was 28-day in-hospital all-cause mortality.

RESULTS

We categorized eligible patients (n = 2202) from 622 hospitals into the rhTM group (n = 726) and control group (n = 1476). Propensity-score matching created 621 matched pairs of patients with and without rhTM. There was neither significant difference in 28-day mortality between the two groups in the unmatched analysis (rhTM vs. control, 25.3 vs. 23.4%, respectively; difference, 1.9%; 95% CI, -1.9 to 5.7) nor in the propensity-score-matched analysis (rhTM vs. control, 26.1 vs. 24.8%, respectively; difference, 1.3%; 95% CI, -3.6 to 6.1). The logistic analysis showed no significant association between the use of rhTM and the mortality in propensity-score-matched patients (OR, 1.1; 95% CI, 0.82-1.4). The instrumental variable analyses, using the hospital rhTM-prescribing proportion as the variable, found that receipt of rhTM was not associated with the reduction in the mortality (risk difference, -6.7%; 95% CI, -16.4 to 3.0).

CONCLUSION

We found no association between administration of rhTM and 28-day mortality in mechanically ventilated patients with septic shock and concurrent DIC after intestinal perforation.

Antimicrobial effects of helix D-derived peptides of human antithrombin III

Antithrombin III (ATIII) is a key antiproteinase involved in blood coagulation. Previous investigations have shown that ATIII is degraded by Staphylococcus aureus V8 protease, leading to release of heparin binding fragments derived from its D helix. As heparin binding and antimicrobial activity of peptides frequently overlap, we here set out to explore possible antibacterial effects of intact and degraded ATIII. In contrast to intact ATIII, the results showed that extensive degradation of the molecule yielded fragments with antimicrobial activity. Correspondingly, the heparin-binding, helix D-derived, peptide FFFAKLNCRLYRKANKSSKLV (FFF21) of human ATIII, was found to be antimicrobial against particularly the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Fluorescence microscopy and electron microscopy studies demonstrated that FFF21 binds to and permeabilizes bacterial membranes. Analogously, FFF21 was found to induce membrane leakage of model anionic liposomes. In vivo, FFF21 significantly reduced P. aeruginosa infection in mice. Additionally, FFF21 displayed anti-endotoxic effects in vitro. Taken together, our results suggest novel roles for ATIII-derived peptide fragments in host defense.

Antithrombin and mortality in severe pneumonia patients with sepsis-associated disseminated intravascular coagulation: an observational nationwide study

BACKGROUND

The association between antithrombin use and mortality in patients with sepsis-associated disseminated intravascular coagulation (DIC) remains controversial.

OBJECTIVES

To examine the hypothesis that antithrombin could be effective in the treatment of patients with sepsis-associated DIC following severe pneumonia.

METHODS

Propensity score and instrumental variable analyses were performed by use of a nationwide administrative database, the Japanese Diagnosis Procedure Combination inpatient database. The main outcome was 28-day mortality.

RESULTS

Severe pneumonia patients diagnosed with sepsis-associated DIC (n = 9075) were categorized into antithrombin (n = 2663) and control (n = 6412) groups. Propensity score matching created a matched cohort of 2194 pairs of patients with and without antithrombin use. Mortality differences were found between the two groups (antithrombin vs. control: unmatched, 40.8% vs. 45.7%; propensity-matched, 40.6% vs. 44.2%; inverse probability-weighted, 41.1% vs. 45.1%). Multiple logistic regression analyses showed an association between antithrombin use and 28-day mortality (unmatched with propensity score adjusted, adjusted odds ratio [OR] 0.87, 95% confidence interval [CI] 0.78-0.97; propensity-matched, adjusted OR 0.85, 95% CI 0.75-0.97; inverse probability-weighted, adjusted OR 0.85, 95% CI 0.79-0.90). An analysis with the hospital antithrombin-prescribing rate as an instrumental variable showed that receipt of antithrombin was associated with a 9.9% (95% CI 3.5-16.3) reduction in 28-day mortality.

CONCLUSIONS

This retrospective, large, nationwide database study demonstrates that antithrombin administration may be associated with reduced 28-day mortality in patients with severe pneumonia and sepsis-associated DIC. A large, multinational randomized trial is required.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Utility of thromboelastography and/or thromboelastometry in adults with sepsis: a systematic review

Introduction

Coagulation abnormalities are frequent in sepsis. Conventional coagulation assays, however, have several limitations. A surge of interest exists in the use of point-of-care tests to diagnose hypo- and hypercoagulability in sepsis.

We performed a systematic review of available literature to establish the value of rotational thromboelastography (TEG) and thromboelastometry (ROTEM) compared with standard coagulation tests to detect hyper- or hypocoagulability in sepsis patients. Furthermore, we assessed the value of TEG/ROTEM to identify sepsis patients likely to benefit from therapies that interfere with the coagulation system.

Methods

MEDLINE, EMBASE, and the Cochrane Library were searched from 1 January 1980 to 31 December 2012. The search was limited to adults, and language was limited to English. Reference lists of retrieved articles were hand-searched for additional studies. Ongoing trials were searched on http://www.controlled-trials.com and http://www.clinicaltrials.gov. Studies addressing TEG/ROTEM measurements in adult patients with sepsis admitted to the ICU were considered eligible.

Results

Of 680 screened articles, 18 studies were included, of which two were randomized controlled trials, and 16 were observational cohort studies. In patients with sepsis, results show both hyper- and hypocoagulability, as well as TEG/ROTEM values that fell within reference values. Both hyper- and hypocoagulability were to some extent associated with diffuse intravascular coagulation. Compared with conventional coagulation tests, TEG/ROTEM can detect impaired fibrinolysis, which can possibly help to discriminate between sepsis and systemic inflammatory response syndrome (SIRS). A hypocoagulable profile is associated with increased mortality. The value of TEG/ROTEM to identify patients with sepsis who could possibly benefit from therapies interfering with the coagulation system could not be assessed, because studies addressing this topic were limited.

Conclusion

TEG/ROTEM could be a promising tool in diagnosing alterations in coagulation in sepsis. Further research on the value of TEG/ROTEM in these patients is warranted. Given that coagulopathy is a dynamic process, sequential measurements are needed to understand the coagulation patterns in sepsis, as can be detected by TEG/ROTEM.

A randomized, controlled, multicenter trial of the effects of antithrombin on disseminated intravascular coagulation in patients with sepsis

INTRODUCTION

To test the hypothesis that the administration of antithrombin concentrate improves disseminated intravascular coagulation (DIC), resulting in recovery from DIC and better outcomes in patients with sepsis, we conducted a prospective, randomized controlled multicenter trial at 13 critical care centers in tertiary care hospitals.

METHODS

We enrolled 60 DIC patients with sepsis and antithrombin levels of 50 to 80% in this study. The participating patients were randomly assigned to an antithrombin arm receiving antithrombin at a dose of 30 IU/kg per day for three days or a control arm treated with no intervention. The primary efficacy end point was recovery from DIC on day 3. The analysis was conducted with an intention-to-treat approach. DIC was diagnosed according to the Japanese Association for Acute Medicine (JAAM) scoring system. The systemic inflammatory response syndrome (SIRS) score, platelet count and global markers of coagulation and fibrinolysis were measured on day 0 and day 3.

RESULTS

Antithrombin treatment resulted in significantly decreased DIC scores and better recovery rates from DIC compared with those observed in the control group on day 3. The incidence of minor bleeding complications did not increase, and no major bleeding related to antithrombin treatment was observed. The platelet count significantly increased; however, antithrombin did not influence the sequential organ failure assessment (SOFA) score or markers of coagulation and fibrinolysis on day 3.

CONCLUSIONS

Moderate doses of antithrombin improve DIC scores, thereby increasing the recovery rate from DIC without any risk of bleeding in DIC patients with sepsis.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000000882.

Update on the Treatment of Disseminated Intravascular Coagulation

Disseminated intravascular coagulation (DIC) is characterized by an acute generalized, widespread activation of coagulation, which results in thrombotic complications, due to the intravascular formation of fibrin, as well as diffuse hemorrhages, due to the consumption of platelets and coagulation factors. In this review, we briefly report the present knowledge about the treatment of DIC. We focus on the current standard treatment of overt DIC in clinical practice. Moreover, particular attention is made to novel therapeutic strategies, who reflect the important progresses in the understanding of the pathogenesis of this syndrome in the last few years.

Animal models of sepsis

Sepsis remains a common, serious, and heterogeneous clinical entity that is difficult to define adequately. Despite its importance as a public health problem, efforts to develop and gain regulatory approval for a specific therapeutic agent for the adjuvant treatment of sepsis have been remarkably unsuccessful. One step in the critical pathway for the development of a new agent for adjuvant treatment of sepsis is evaluation in an appropriate animal model of the human condition. Unfortunately, the animal models that have been used for this purpose have often yielded misleading findings. It is likely that there are multiple reasons for the discrepancies between the results obtained in tests of pharmacological agents in animal models of sepsis and the outcomes of human clinical trials. One of important reason may be that the changes in gene expression, which are triggered by trauma or infection, are different in mice, a commonly used species for preclinical testing, and humans. Additionally, many species, including mice and baboons, are remarkably resistant to the toxic effects of bacterial lipopolysaccharide, whereas humans are exquisitely sensitive. New approaches toward the use of animals for sepsis research are being investigated. But, at present, results from preclinical studies of new therapeutic agents for sepsis must be viewed with a degree of skepticism.

Studies on therapeutic effects and pathological features of an antithrombin preparation in septic disseminated intravascular coagulation patients

PURPOSE

Few reports have been made on the therapeutic effects as well as pathological features of an antithrombin preparation in patients diagnosed with septic disseminated intravascular coagulation (DIC) by the diagnostic criteria for acute DIC.

MATERIALS AND METHODS

A total of 88 sepsis patients who had received inpatient hospital care during the period from January 2000 through December 2008 were divided into two groups, an antithrombin group and a non-antithrombin group, to study the outcomes. Furthermore, the relationship between sepsis-related factors and DIC in 44 patients was studied.

RESULTS

The antithrombin group contained 34 patients, and the non-antithrombin group contained 54 patients. The outcomes were significantly better in the antithrombin group. The levels of protein C were low in DIC patients.

CONCLUSION

Our results suggest that early administration of antithrombin might improve outcomes of septic DIC patients in the diagnostic criteria for Japanese Association for Acute Medicine acute DIC.

Enoxaparin versus unfractioned heparin as anticoagulant for continuous venovenous hemodialysis: a randomized open-label trial

AIM

In this study we aimed to compare the efficacy and safety of enoxaparin with unfractioned heparin (UFH) as anticoagulant for continuous venovenous hemodialysis (CVVHD).

METHODS

An open-label randomized controlled trial was carried out in an intensive care unit (ICU) where 40 patients with acute renal failure (ARF) who needed continuous renal replacement therapy were randomized to receive UFH (n=21) or enoxaparin (n=19). Coagulation parameters were evaluated, and antithrombotic activity of UFH was measured by activated partial thromboplastin time (aPTT) and for enoxaparin by anti-factor Xa activity. Primary outcomes were thrombosis of the extracorporeal circuit and bleeding, classified as major or minor.

RESULTS

Minor bleeding episodes were observed only in patients anticoagulated with enoxaparin (26 vs. 0%, p=0.018). Comparing patients with or without bleeding after 24 hours of therapy, the level of anticoagulation tended to be higher (anti-factor Xa: 1.62 vs. 1.13 IU/mL, p=0.09) and the platelet count to be lower [107+/-53 vs. 229+/-84 (x10(3)/microL), p=0.09] in patients who bled, but without statistical difference. Filter life span of enoxaparin and UFH groups was similar (43+/-15 vs. 52+/-18 hr, p=0.10), as well as the proportion of circuit clotting.

CONCLUSION

Weight-unadjusted enoxaparin in patients with ARF in CVVHD was associated with an increased rate of bleeding, a finding that addresses the need to adjust drug dose and to monitor anti-factor Xa activity during dialysis. No benefit to prolong dialysis circuit survival was found with enoxaparin. In patients who do not present contraindication for systemic anticoagulation, UFH remains an effective and low-cost option.

Recombinant activated factor VII attenuates major arterial bleeding in noncoagulopathic rabbits

BACKGROUND AND OBJECTIVE

Recombinant activated factor VII (rFVIIa), which is used off-label as an adjuvant therapy for uncontrolled and life-threatening bleeding, might also attenuate intractable bleeding related to macrovascular arterial lesions. Here we evaluated the efficacy of rFVIIa in sealing a large arterial wound in haemostatically competent rabbits.

METHODS

Sixty male New Zealand rabbits were randomly divided into vehicle control and 80 and 200 μg kg⁻¹ rFVIIa groups (n = 20 animals each). A standardized wound of the isolated right carotid artery was made in all rabbits with an 18-G catheter. Bleeding, which was limited by mild compression, was assessed every minute. At 5 min, an intravenous bolus of vehicle or human rFVIIa was given and the animals were further observed for 1 h. Efficacy was assessed from the bleeding duration and blood mass lost. Statistical significance was defined as P less than 0.05. All investigators were blinded to the treatment the animals received.

RESULTS

The bleeding duration and blood mass lost were significantly reduced in both rFVIIa dosage groups as compared with the vehicle control group. For the vehicle, 80 and 200 μg kg⁻¹ rFVIIa groups, the median bleeding durations were 56 min (range 7-60 min), 15 min (range 5-60 min) and 10 min (range 5-60 min), respectively; and the median blood mass losses were 22.5 g (range 1-58 g), 12 g (range 0-36 g) and 5 g (range 0-31 g), respectively. The prothrombin time was shorter in the rFVIIa groups. Visual inspection of the carotid artery and microscopic analysis of the liver and kidney revealed neither gross thrombi nor entrapped microthrombi in any rabbit.

CONCLUSION

Recombinant FVIIa at 80 or 200 μg kg⁻¹ promoted the sealing of a large and slightly compressed arterial wound in rabbits. These results suggest a potential role for the drug in the management of massive bleeds due to an arterial lesion when surgical intervention is not immediately and readily available. Safety should remain a matter of concern.

The host response to sepsis and developmental impact

Invasion of the human by a pathogen necessitates an immune response to control and eradicate the microorganism. When this response is inadequately regulated, systemic manifestations can result in physiologic changes described as "sepsis." Recognition, diagnosis, and management of sepsis remain among the greatest challenges shared by the fields of neonatology and pediatric critical care medicine. Sepsis remains among the leading causes of death in both developed and underdeveloped countries and has an incidence that is predicted to increase each year. Despite these sobering statistics, promising therapies derived from preclinical models have universally failed to obviate the substantial mortality and morbidity associated with sepsis. Thus, there remains a need for well-designed epidemiologic and mechanistic studies of neonatal and pediatric sepsis to improve our understanding of the causes (both early and late) of deaths attributed to the syndrome. In reviewing the definitions and epidemiology, developmental influences, and regulation of the host response to sepsis, it is anticipated that an improved understanding of this host response will assist clinician-investigators in identifying improved therapeutic strategies.

Has mortality from sepsis improved and what to expect from new treatment modalities: review of current insights

BACKGROUND

The incidence of sepsis is increasing continuously, making mortality rate reduction through improved intensive care unit (ICU) care and new treatment modalities a pressing issue. This study aimed to provide insight into the effects of modern ICU care on mortality trends from severe sepsis and to provide a quantitative review of the relative effectiveness of new treatment modalities in reducing deaths.

METHODS

Mortality data from severe sepsis were extracted from the control arms of several large randomized trials of sepsis treatment published within the last two decades. The effectiveness of recent treatment strategies was expressed as the number of patients it is necessary to treat by that method to save one life (number needed to treat: NNT).

RESULTS

Death from severe sepsis showed a decline from 44% to 35% between 1990 and 2000. The two most effective strategies in critically ill patients are early appropriate antibiotics (NNT 3; 95% confidence interval [CI] 2, 4) and early goal-directed therapy (NNT 6; 95% CI 4, 24). Infusion of recombinant human activated protein C is the most effective anticoagulant therapy (NNT 15; 95% CI 10, 27). Intensive insulin therapy is only moderately effective (NNT 27; 95% CI 15, 124).

CONCLUSIONS

The mortality rate from severe sepsis has decreased significantly with modernization of ICU care. New therapeutic strategies may reduce further the mortality rate. However, focused implementation of these new strategies in accordance with their relative effectiveness is needed before we can expect to see their true effect on mortality rates.

Postoperative activity, but not preoperative activity, of antithrombin is associated with major adverse cardiac events after coronary artery bypass graft surgery

BACKGROUND

Low levels of antithrombin (AT) have been independently associated with prolonged intensive care unit stay and an increased incidence of neurologic and thromboembolic events after cardiac surgery. We hypothesized that perioperative AT activity is independently associated with postoperative major adverse cardiac events (MACEs) in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

We prospectively studied 1403 patients undergoing primary CABG surgery with cardiopulmonary bypass (CPB) (http://clinicaltrials.gov/show/NCT00281164). The primary clinical end point was occurrence of MACE, defined as a composite outcome of any one or more of the following: postoperative death, reoperation for coronary graft occlusion, myocardial infarction, stroke, pulmonary embolism, or cardiac arrest until first hospital discharge. Plasma AT activity was measured before surgery, after post-CPB protamine, and on postoperative days (PODs) 1-5. Multivariate logistic regression modeling was performed to estimate the independent effect of perioperative AT activity upon MACE.

RESULTS

MACE occurred in 146 patients (10.4%), consisting of postoperative mortality (n = 12), myocardial infarction (n = 108), stroke (n = 17), pulmonary embolism (n = 8), cardiac arrest (n = 16), or a subsequent postoperative or catheter-based treatment for graft occlusion (n = 6). AT activity at baseline did not differ between patients with (0.91 ± 0.13 IU/mL; n = 146) and without (0.92 ± 0.13 IU/mL; n = 1257) (P = 0.18) MACE. AT activity in both groups was markedly reduced immediately after CPB and recovered to baseline values over the ensuing 5 PODs. Postoperative AT activity was significantly lower in patients with MACE than those without MACE. After adjustment for clinical predictors of MACE, AT activity on PODs 2 and 3 was associated with MACE.

CONCLUSIONS

Preoperative AT activity is not associated with MACE after CABG surgery. MACE is independently associated with postoperative AT activity but only at time points occurring predominantly after the MACE.

The response of antithrombin III activity after supplementation decreases in proportion to the severity of sepsis and liver dysfunction

The decrease in the antithrombin III activity is thought to result from consumption by ongoing coagulation, degradation by neutrophil elastase, capillary leak syndrome, and impaired synthesis. A retrospective data analysis of patients with sepsis was conducted to investigate the response of antithrombin III activity after supplementation in patients with sepsis, and to determine what factors affect the response of antithrombin III activity. The study included 42 patients with sepsis, 75 patients with severe sepsis, and 65 patients with septic shock, who were administered antithrombin III. Antithrombin III activity, platelet counts, coagulation, and fibrinolytic markers were collected before administration and 24 h after the supplementation. In the patients with septic shock, the response of antithrombin III activity after supplementation was 0.37% +/- 1.21%/IU per kg body weight, which was significantly lower in comparison with those in the patients with sepsis (1.81 +/- 1.75; P < 0.001) or severe sepsis (1.36 +/- 1.65; P < 0.001). The patients with liver dysfunction had significantly lower response to antithrombin III activity than that of the patients without liver dysfunction (P < 0.0001). A stepwise multiple linear regression analysis revealed that the severity of sepsis and liver function were independent predictors for the response to antithrombin III activity. These results suggest that the response to antithrombin III supplementation may be affected by both a systemic inflammation and impaired synthesis in patients with sepsis.

Dysregulation of coagulation in cerebral malaria

Cerebral malaria (CM) is a life-threatening complication of Plasmodium falciparum infection and represents a major cause of morbidity and mortality worldwide. The nature of the pathogenetic processes leading to the cerebral complications remains poorly understood. It has recently emerged that in addition to their conventional role in the regulation of haemostasis, coagulation factors have an inflammatory role that is pivotal in the pathogenesis of a number of acute and chronic conditions, including CM. This new insight offers important therapeutic potential. This review explores the clinical, histological and molecular evidence for the dysregulation of the coagulation system in CM, looking at possible underlying mechanisms. We discuss areas for future research to improve understanding of CM pathogenesis and for the development of new therapeutic approaches.

Antithrombin III for critically ill patients

BACKGROUND

Critical illness is associated with uncontrolled inflammation and vascular damage which can result in multiple organ failure and death. Antithrombin III (AT III) is an anticoagulant with anti-inflammatory properties but the efficacy and any harmful effects of AT III supplementation in critically ill patients are unknown.

OBJECTIVES

To assess the benefits and harms of AT III in critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); MEDLINE; EMBASE; Science Citation Index Expanded; International Web of Science; CINAHL; LILACS; and the Chinese Biomedical Literature Database (up to November 2006). We contacted authors and manufacturers in the field.

SELECTION CRITERIA

We included all randomized clinical trials, irrespective of blinding or language, that compared AT III with no intervention or placebo in critically ill patients.

DATA COLLECTION AND ANALYSIS

Our primary outcome measure was mortality. We each independently abstracted data and resolved any disagreements by discussion. We presented pooled estimates of the intervention effects on dichotomous outcomes as relative risks (RR) with 95% confidence intervals (CI). We performed subgroup analyses to assess risk of bias, the effect of AT III in different populations (sepsis, trauma, obstetric, and paediatric patients), and the effect of AT III in patients with or without the use of concomitant heparin. We assessed the adequacy of the available number of participants and performed a trial sequential analysis to establish the implications for further research.

MAIN RESULTS

We included 20 randomized trials with a total of 3458 participants; 13 of these trials had high risk of bias. When we combined all trials, AT III did not statistically significantly reduce overall mortality compared with the control group (RR 0.96, 95% CI 0.89 to 1.03; no heterogeneity between trials). A total of 32 subgroup and sensitivity analyses were carried out. Analyses based on risk of bias, different populations, and the role of adjuvant heparin gave insignificant differences. AT III reduced the multiorgan failure score among survivors in an analysis involving very few patients. AT III increased bleeding events (RR 1.52, 95% CI 1.30 to 1.78).

AUTHORS' CONCLUSIONS

AT III cannot be recommended for critically ill patients based on the available evidence. A randomized controlled trial of AT III, without adjuvant heparin, with prespecified inclusion criteria and good bias protection is needed.

Intracellular and extracellular serpins modulate lung disease

An imbalance between peptidases and their inhibitors leads to pulmonary disease. Imbalances occur in the adult and the neonate at risk for a specific set of lung pathologies. Serpins (serine peptidase inhibitors) make up the major source of antipeptidase activity in the lung. The purpose of this review is to describe the serpin mechanism of inhibition, their roles in the normal and pathological lung and their potential as therapeutic agents.

A systematic review of antithrombin concentrate use in patients with disseminated intravascular coagulation of severe sepsis

The objective was to estimate the effect of antithrombin therapy on mortality in disseminated intravascular coagulation (DIC) of severe sepsis and septic shock. Randomized clinical trials (RCT) on patients with DIC and severe sepsis or septic shock assigned to intravenous antithrombin or placebo were searched. Eligible studies reported death as the outcome measure. Of 35 RCT, 32 trials were excluded because patients were not randomized to antithrombin versus placebo, or no separate data on patients with DIC were given. In three RCT, 364 patients with severe sepsis or septic shock and DIC were randomized. The disease severity, definition of DIC, dose and duration of treatment varied among the trials. In two of the three RCT, data were from subgroup analyses (patients not stratified by DIC). The combined odds ratio for short-term all-cause mortality in those who received antithrombin was 0.649 (95% confidence interval, 0.422-0.998). Data on bleeding complications in patients treated with antithrombin were reported only in one of the RCT and were not considered suitable for systematic safety estimation. In sepsis patients with DIC, administration of antithrombin concentrate may increase overall survival. Current available evidence, however, is not suited to sufficiently inform clinical practice.