Thromboembolic Risk of 4-Factor Prothrombin Complex Concentrate versus Fresh Frozen Plasma for Urgent Warfarin Reversal in the Emergency Department

Falsely prolonged prothrombin time test in a patient with erythrocytosis: a case report

The prothrombin time (PT) test is commonly used to monitor deficiencies in coagulation factors. A prolonged PT may indicate a deficiency of factors II, V, VII, X, and fibrinogen, or the presence of an inhibitor. However, further tests are required to differentiate between a true factor deficiency and the presence of an inhibitor. It is important to note that falsely prolonged PT can lead to misdiagnosis and inappropriate clinical intervention that can have life-threatening consequences. A 19-year-old woman with elevated hematocrit levels and prolonged PT was diagnosed with secondary erythrocytosis due to cyanotic congenital heart disease with ventricular septal defect (VSD). However, further investigation revealed that the prolonged PT result was false. Excess citrate in the blood sample, caused by polycythemia, led to this misleading outcome, resulting in unnecessary and potentially harmful treatment. This incident emphasizes the importance of laboratory personnel and clinicians being aware of the test's limitations. Not only should specialists in thrombosis and hemostasis possess this knowledge, but it is also pertinent for general laboratory staff, as well as laboratory directors and specialists. The significance of accurate laboratory testing for the proper diagnosis and treatment of patients is highlighted in this case.

A Rare Case of Skin Necrosis Following Extravasation of Prothrombin Complex Concentrate (PCC) Infusion During Warfarin Reversal

Warfarin-induced skin necrosis is a well-documented complication that can occur following commencement of warfarin. However, skin necrosis following extravasation of prothrombin complex concentrate (PCC) infusion is a very rare adverse event that is not commonly documented. This case illustrates the possibility of developing skin necrosis following the administration of an anticoagulation reversal agent rather than from anticoagulation itself. We report a case of a 58-year-old male who developed skin necrosis at the site of PCC infusion in the right upper extremity (RUE) for warfarin reversal of an elevated international normalized ratio (INR). The skin necrosis progressed into a full thickness chemical burn. As a result, the patient underwent allograft followed by split thickness autograft and RECELL placement. This case presentation describes the first reported case of skin necrosis following extravasation of PCC infusion during warfarin reversal.

Anticoagulants and fracture morphology have a significant influence on total blood loss after proximal femur fractures

INTRODUCTION

Blood loss after proximal femoral fractures is an important risk factor for postoperative outcome and recovery. The purpose of our study was to investigate the total blood loss depending on fracture type and additional risks, such as anticoagulant use, to be able to recognize vulnerable patients depending on planned surgery and underlying comorbidities.

MATERIALS AND METHODS

A retrospective single center study including 1478 patients treated operatively for a proximal femoral fracture between January 2016 and June 2020 at a level I trauma center. Patient data, surgical procedure, time to surgery, complications and mortality were assessed. Lab data including hemoglobin and transfusion rates were collected. The Mercuriali formula was implemented to calculate total blood loss. Linear regression was performed to identify influencing factors.

RESULTS

One thousand four hundred seventy-eight mainly female patients were included in the study (mean age: 79.8 years) comprising 667 femoral neck fractures, 704 pertrochanteric- and 107 subtrochanteric fractures. Nearly 50% of the cohort were on anticoagulants or anti- platelet therapy. At time of admission average hemoglobin was 12.1 g/l. Linear regression proved fracture morphology, age, BMI, in-house mortality and anticoagulant use to have crucial influence on postoperative blood loss. Femoral neck fractures had a blood loss of 1227.5 ml (SD 740.4 ml), pertrochanteric fractures lost 1,474.2 ml (SD 830 ml) and subtrochanteric femoral fractures lost 1902.2 ml (SD 1,058 ml).

CONCLUSIONS

Hidden blood loss is underestimated. Anticoagulant use, fracture type, gender and BMI influence the total blood loss. Hemoglobin levels should be monitored closely. Within 48 h there was no increased mortality, so adequate time should be given to reduce anticoagulant levels and safely perform surgery.

Blasting the myth of predictive INR changes related to plasma transfusion: an academic institution's experience

INTRODUCTION

Plasma transfusion is a common therapeutic strategy used to lower international normalized ratio (INR) values in the non-emergent setting. However, due to lack of evidence of its efficacy, standardized guidelines for this practice have not been well established.

METHODS

This retrospective observational cohort study analyzed 276 inpatient encounters that involved plasma transfusions focusing on change in INR values from pre- to post-transfusion, with respect to the following predictor variables: vitamin K co-administration, number of plasma units transfused, order indication and body mass index (BMI).

RESULTS

The overall average change in the INR was 1.35. Patients who received vitamin K showed an average change of 2.51, while patients that did not receive vitamin K demonstrated an average change of 0.70. Increased numbers of plasma units transfused showed benefit up to three-unit orders. Greater decreases in the INR were observed for patients requiring plasma for anticoagulation reversal or active bleeding. There was no significant difference in the change in INR based on the BMI. By multivariate and regression analyses, the stepwise addition of each successive predictor variable demonstrated an increase in the shared variance in the outcome of the post-transfusion INR: the pre-transfusion INR and vitamin K co-administration alone was not significant (p = 0.45); the additional number of plasma units transfused was significant (R² = 0.13, p < 0.001), and; the subsequent additional plasma order indications (R² = 0.19, p < 0.001) and BMI (R² = 0.18, p < 0.001) were increasingly significant.

CONCLUSION

Taking into consideration the combination of multiple predictive factors may aid in a more efficient use of plasma products.

A short review of ciraparantag in perspective of the currently available anticoagulant reversal agents

Despite the improved safety-profile of direct oral anticoagulants (DOACs), bleeding complications remain an important side effect of anticoagulant treatment. Although anticoagulant-specific antidotes are available, an universal anticoagulant reversal agent in case of life-threatening bleeding or emergency surgery is not yet available. Ciraparantag, a synthetic small molecule that inactivates heparins and DOAC, is a promising new reversal agent that has been investigated in phase 2 trials. In this short review we provide an overview of the preclinical and clinical evidence of ciraparantag, and compare strengths and weaknesses of ciraparantag and the currently available anticoagulant reversal strategies.

Application of fresh frozen plasma transfusion in the management of excessive warfarin-associated anticoagulation

Warfarin is a commonly used oral anticoagulant. Patients with artificial valve replacement, atrial fibrillation, pulmonary embolism, deep vein thrombosis, and other diseases require long-term anticoagulant oral treatment with warfarin. As warfarin exhibits prompt action with long maintenance time, it has become a key drug for the treatment of patients at risk of developing thrombosis or thromboembolism. Warfarin is a bican coumarin anticoagulant, that exhibits competitive action against vitamin K as its mechanism of action, thereby inhibiting the synthesis of coagulation factors—predominantly the vitamin K-dependent coagulation factors II, VII, IX, and X—in hepatocytes. Long-term warfarin is known to significantly increase the risk of organ bleeding in some patients, while some patients may need to reverse the anticoagulation effect. For instance, patients scheduled for emergency or invasive surgery may require rapid anticoagulation reversal. During such medical circumstances, fresh frozen plasma (FFP) is clinically used for the reversal of excess warfarin-associated anticoagulation, as it contains all the coagulation factors that can alleviate the abnormal blood anticoagulation status in such patients. Accordingly, this article aims to perform an in-depth review of relevant literature on the reversal of warfarin with FFP, and insightful deliberation of the application and efficacy of this clinical intervention.

Evaluation of the prothrombotic potential of four-factor prothrombin complex concentrate (4F-PCC) in animal models

OBJECTIVES

Acquired coagulopathy may be associated with bleeding risk. Approaches to restore haemostasis include administration of coagulation factor concentrates, but there are concerns regarding potential prothrombotic risk. The present study assessed the prothrombotic potential of four-factor prothrombin complex concentrate (4F-PCC) versus activated PCC (aPCC) and recombinant factor VIIa (rFVIIa), using three preclinical animal models.

METHODS

The first model was a modified Wessler model of venous stasis-induced thrombosis in rabbit, focusing on dilutional coagulopathy; the second model employed the same system but focused on direct oral anticoagulant reversal (i.e. edoxaban). The third model assessed the prothrombotic impact of 4F-PCC, aPCC and rFVIIa in a rat model of ferric chloride-induced arterial thrombosis.

RESULTS

In the first model, thrombi were observed at aPCC doses ≥10 IU/kg (therapeutic dose 100 IU/kg) and rFVIIa doses ≥50 μg/kg (therapeutic dose 90 μg/kg), but not 4F-PCC 50 IU/kg (therapeutic dose 50 IU/kg). The impact of 4F-PCC (up to 300 IU/kg) on thrombus formation was evident from 10 minutes post-administration, but not at 24 hours post-administration; this did not change with addition of tranexamic acid and/or fibrinogen concentrate. 4F-PCC-induced thrombus formation was lower after haemodilution versus non-haemodilution. In the second model, no prothrombotic effect was confirmed at 4F-PCC 50 IU/kg. The third model showed lower incidence of thrombus formation for 4F-PCC 50 IU/kg versus aPCC (50 U/kg) and rFVIIa (90 μg/kg).

CONCLUSIONS

These results suggest that 4F-PCC has a low thrombotic potential versus aPCC or rFVIIa, supporting the clinical use of 4F-PCC for the treatment of coagulopathy-mediated bleeding.

Prothrombin Complex Concentrate for Trauma Induced Coagulopathy: A Systematic Review and Meta-Analysis

Background

Optimal management for trauma-induced coagulopathy (TIC) is a clinical conundrum. In conjunction with the transfusion of fresh-frozen plasma (FFP), additional administration of prothrombin complex concentrate (PCC) was proposed to bring about further coagulative benefit. However, investigations evaluating the efficacy as well as corresponding side effects were scarce and inconsistent. The aim of this study was to systematically review current literature and to perform a meta-analysis comparing FFP+PCC with FFP alone.

Methods

Web search followed by manual interrogation was performed to identify relevant literatures fulfilling the following criteria, subjects as TIC patients taking no baseline anticoagulants, without underlying coagulative disorders, and reported clinical consequences. Those comparing FFP alone with PCC alone were excluded. Comprehensive Meta-analysis software was utilized, and statistical results were delineated with odd ratio (OR), mean difference (MD), and 95% confidence interval (CI). I² was calculated to determine heterogeneity. The primary endpoint was set as all-cause mortality, while the secondary endpoint consisted of international normalized ratio (INR) correction, transfusion of blood product, and thrombosis rate.

Results

One hundred and sixty-four articles were included for preliminary evaluation, 3 of which were qualified for meta-analysis. A total of 840 subjects were pooled for assessment. Minimal heterogeneity was present in the comparisons (I² < 25%). In the PCC + FFP cohort, reduced mortality rate was observed (OR: 0.631; 95% CI: 0.450-0.884, p = 0.007) after pooling. Meanwhile, INR correction time was shorter under PCC + FFP (MD: -608.300 mins, p < 0.001), whilst the rate showed no difference (p = 0.230). The PCC + FFP group is less likely to mandate transfusion of packed red blood cells (p < 0.001) and plasma (p < 0.001), but not platelet (p = 0.615). The incidence of deep vein thrombosis was comparable in the two groups (p = 0.460).

Conclusions

Compared with FFP only, PCC + FFP demonstrated better survival rate, favorable clinical recovery and no elevation of thromboembolism events after TIC.

[Management of bleeding in patients on antithrombotic therapy]

BACKGROUND

Severe bleeding under antithrombotic therapy is common and challenging in intensive care medicine; on the one hand, rapid bleeding control must be achieved and, on the other hand, thromboembolic complications must be avoided.

AIMS

The paper will provide a brief overview of direct oral anticoagulants, therapeutic options and precise instructions for dealing with severe bleeding.

RESULTS

In addition to general measures in direct oral anticoagulant (DOAC)-associated major bleeding, prothrombin complex concentrate (PCC), idarucizumab and andexanet alfa are available as specific antidote therapy. In case of bleeding under heparin therapy, protamine sulfate is available as a possible antidote.

CONCLUSIONS

In particular, the importance of andexanet alfa in the treatment of factor Xa inhibitor-associated bleeding requires further investigation.

Isovolemic filter-based therapeutic plasma-exchange with fresh frozen plasma is associated with minimal thromboelastometric changes in noncoagulopathic patients

The aim of this study was to assess the effects of isovolemic therapeutic plasma-exchange using fresh frozen plasma on coagulations parameters assessed by standard coagulation tests and rotational thromboelastometry in noncoagulopathic patients. Twenty patients who underwent isovolemic filter-based therapeutic plasma-exchange of approximately 1.5 plasma volume per session were included in the current study. Standard coagulation tests and rotational thromboelastometry (ExTEM, InTEM, FibTEM and ApTEM) were performed 30 min before and after the procedure. Isovolemic therapeutic plasma-exchange was associated with decreased fibrinogen levels (P = 0.01). Thromboelastometric assay demonstrated an increased clotting time in both ExTEM (P = 0.03) and InTEM (P = 0.01) and a decreased thrombodynamic potential index in ExTEM (P = 0.03). No significant difference in FibTEM maximum clot firmness was recorded (P = 0.41). Therapeutic plasma-exchange in noncoagulopathic patients is associated with minimal changes in thromboelastometric parameters, mainly by an increase in clotting time in both intrinsic and extrinsic pathways.

Antiplatelet and anticoagulation strategies for left ventricular assist devices

Left ventricular assist devices (LVAD) have revolutionized the management of advanced heart failure. However, complications rates remain high, among which hemorrhagic and thrombotic complications are the most important. Antiplatelet and anticoagulation strategies form a cornerstone of LVAD management and may directly affect LVAD complications. Concurrently, LVAD complications influence anticoagulation and anticoagulation management. A thorough understanding of device, patient, and management, including anticoagulation and antiplatelet therapies, are important in optimizing LVAD outcomes. This article provides a comprehensive state of the art review of issues related to antiplatelet and anticoagulation management in LVADs. We start with a historical overview, the epidemiology and pathophysiology of bleeding and thrombotic complications in LVADs. We then discuss platelet and anticoagulation biology followed by considerations prior to, during, and after LVAD implantation. This is followed by discussion of anticoagulation and the management of thrombotic and hemorrhagic complications. Specific problems, including management of heparin-induced thrombocytopenia, anticoagulant reversal, novel oral anticoagulants, artificial heart valves, and noncardiac surgeries are covered in detail.

Plasma Transfusion Practice in Adult Surgical Patients: Systematic Review of the Literature

Background

Plasma transfusions are most commonly used therapeutically for bleeding or prophylactically in non-bleeding patients prior to invasive procedures or surgery. Although plasma transfusions generally seem to decline, plasma usage for indications that lack evidence of efficacy prevail.

Summary

There is wide international, interinstitutional, and interindividual variance regarding the compliance with guidelines based on published references, supported by appropriate testing. There is furthermore a profound lack of evidence from randomized controlled trials comparing the effect of plasma transfusion with that of other therapeutic interventions for most indications, including massive bleeding. The expected benefit of a plasma transfusion needs to be balanced carefully against the associated risk of adverse events. In light of the heterogeneous nature of bleeding conditions and their rapid evolvement over time, fibrinogen and factor concentrate therapy, directed at specific phases of coagulation identified by alternative laboratory assays, may offer advantages over conventional blood product ratio-driven resuscitation. However, their outcome benefit has not been demonstrated in well-powered prospective trials. This systematic review will detail the current evidence base for plasma transfusion in adult surgical patients.

Gastrointestinal Bleeding as a Complication in Continuous Flow Ventricular Assist Devices: A Systematic Review With Meta-Analysis

Background

The use of ventricular assist devices (VADs) has become predominant in this era of medicine. It is commonly used as a bridge to transplant, recovery and as a destination therapy for patients with severe heart failure, who are not responsive to maximum optimal management or ineligible for transplant. However, several complications are known to occur with the use of these devices. In this research, we will compare gastrointestinal bleeding in patients who used centrifugal flow versus axial flow VADs. We hope that the result of this meta-analysis and the review presented provide adequate information to future researchers, physicians and other healthcare professionals who are interested in this topic.

Methods

Published articles evaluated for inclusion were obtained from MEDLINE (PubMed), Cochrane, EBSCO, clinicaltrials.gov, and international clinical trials registry. This research was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Procured articles were reviewed by two independent reviewers. Only randomized control trials and observational studies were used. Quality assessment was done with Cochrane Collaboration’s tool (RoB.2 with visualization through robviz) and Newcastle-Ottawa Scale (NOS). Data analysis was carried out with the use of R data analysis tool (version 4.0.0; release date: April 24th, 2020).

Results

At the end of this meta-analysis, the occurrence of gastrointestinal bleeding was not significantly different between both groups; with odds ratio (OR): 0.81; 95% confidence interval (CI): 0.65 - 1.00; P value = 0.05. Between-study variance (Tau-squared) was zero (0), standard error (SE) = 0.06. The degree of heterogeneity measured with I-squared statistic was 0% (minimal). Egger’s regression test was not statistically significant, P = 0.93. Symmetry of distribution was observed on the funnel plot. Trim and fill analysis showed no missing studies on the left; SE = 1.68.

Conclusions

The result obtained from this research indicates that the occurrence of gastrointestinal bleeding is not significantly different in both groups of patients, irrespective of the type of continuous flow VAD used. Although, the study sample used in this meta-analysis was limited.

A European consensus statement on the use of four-factor prothrombin complex concentrate for cardiac and non-cardiac surgical patients

Modern four-factor prothrombin complex concentrate was designed originally for rapid targeted replacement of the coagulation factors II, VII, IX and X. Dosing strategies for the approved indication of vitamin K antagonist-related bleeding vary greatly. They include INR and bodyweight-related protocols as well as fixed dose regimens. Particularly in the massively bleeding trauma and cardiac surgery patient, four-factor prothrombin complex concentrate is used increasingly for haemostatic resuscitation. Members of the Transfusion and Haemostasis Subcommittee of the European Association of Cardiothoracic Anaesthesiology performed a systematic literature review on four-factor prothrombin complex concentrate. The available evidence has been summarised for dosing, efficacy, drug safety and monitoring strategies in different scenarios. Whereas there is evidence for the efficacy of four-factor prothrombin concentrate for a variety of bleeding scenarios, convincing safety data are clearly missing. In the massively bleeding patient with coagulopathy, our group recommends the administration of an initial bolus of 25 IU.kg^-1 . This applies for: the acute reversal of vitamin K antagonist therapy; haemostatic resuscitation, particularly in trauma; and the reversal of direct oral anticoagulants when no specific antidote is available. In patients with a high risk for thromboembolic complications, e.g. cardiac surgery, the administration of an initial half-dose bolus (12.5 IU.kg^-1 ) should be considered. A second bolus may be indicated if coagulopathy and microvascular bleeding persists and other reasons for bleeding are largely ruled out. Tissue-factor-activated, factor VII-dependent and heparin insensitive point-of-care tests may be used for peri-operative monitoring and guiding of prothrombin complex concentrate therapy.