Bench-to-bedside review: Optimising emergency reversal of vitamin K antagonists in severe haemorrhage - from theory to practice

A Brief Review on Determination of Acenocoumarol in Biological and Pharmaceutical Specimens: Analytical Methodologies

Acenocoumarol is an oral anticoagulant medicinal agent is frequently prescribed for the prophylaxis and the management of thromboembolic events. Acenocoumarol is prescribed in the form of racemic mixture and S- form is a more influential isomer. Acenocoumarol starts quickly with action and absorption, and the effect lasts for 15-20 h. In most patients, the therapeutic prothrombin range is caused 36 h after the primary dose. This review offers a detailed overview of the various analytical methodologies published in the literature from 1976 to uptil now for evaluation acenocoumarol and its combinations in specimens. The present review also stated the chiral analytical methods for the quantification of its enantiomers. A detailed study of the work revealed several analytical methodologies are routinely used for estimation of acenocoumarol includes UV/Vis-Spectrophotometry, liquid chromatography-mass spectrophotometry, high-performance liquid-chromatography, gas chromatography, high-performance thin-layer chromatography, capillary electrophoresis, Fourier-transform infrared spectroscopy and many miscellaneous techniques. Pharmaceutical analysis carried out the prominent task to understand the knowledge of the physicochemical properties of the medicinal agent; since the establishment of a new analytical method is still a challenging task for a research scientist. Thus, the present review will help to research scientist for the development of new analytical methods for the acenocoumarol.

Effect of Quinolones Versus Cefixime on International Normalized Ratio Levels After Valve Replacement Surgery with Warfarin Therapy

Background and Objectives: A dispute over interaction of warfarin with two quinolones—i.e., moxifloxacin and levofloxacin—leading to significant increase in international normalized ratio (INR) levels and coagulopathies is currently in debate. The study objective was to compare the INR values due to addition of quinolones and cefixime in warfarin treated patients after replacement of disease valves with metallic valves. Material and Methods: A prospective evaluation of patients who undergone valve replacement surgeries in the cardiology hospital setup in Pakistan during the period 2018–2019 was done, including all those subjects treated concurrently with levofloxacin, moxifloxacin, cefixime, and warfarin for the study. Data organized included demographic information, concurrent medications, and appropriate analytical parameters, especially INR values taken before and within seven days after prescribing three antibiotics in discharged patients who had undergone valve replacement surgeries. Patients for whom laboratory INR values were not given at the time of discharge and with deranged liver function, renal function, low albumin levels, and febrile patients were removed from study. Furthermore, patients were advised on possible food interactions and evaluated to examine if these factors have any possible influence on the interaction being studied. Results: Differences in INR were analyzed statistically by means of SPSS analysis before and after the possible interaction. Following the administration of levofloxacin and moxifloxacin to warfarin therapy, statistical analysis showed remarkable increase in INR (p < 0.001) and no significant change in INR was observed after cefixime treatment (p > 0.05). Conclusion: Results showed that, after adding levofloxacin and moxifloxacin in patients on warfarin, therapy contributed to remarkable increase in INR. However, addition of cefixime prevented frequent coagulopathies; therefore, close monitoring of INR and switching to a safe antibiotic such as cefixime is recommended.

Transfusion-Associated Circulatory Overload as a Result of Plasma Transfusion to Correct International Normalized Ratio Before an Invasive Procedure: A Case Report

Plasma transfusion is commonly used to correct elevated international normalized ratio (INR) before invasive procedures. A 54-year-old woman presented to the emergency department with abdominal pain. Workup revealed Streptococcus pneumoniae peritonitis. Her hospitalization was complicated by respiratory failure, fluid overload, atrial fibrillation, and acute kidney injury. Patient underwent 2 paracentesis (9 L removed). Four units of plasma were transfused to correct an INR of 3.0 (goal 1.5) for a transjugular intrahepatic portosystemic shunt procedure. INR remained at 1.9, and she developed acute pulmonary edema and died within 24 hours. Prothrombin complex concentrates may have been a more appropriate treatment option in this case.

Benefits and harms of 4-factor prothrombin complex concentrate for reversal of vitamin K antagonist associated bleeding: a systematic review and meta-analysis

Prothrombin complex concentrate (PCC) is used for reversal of vitamin K antagonists (VKA) in patients with bleeding complications. This study aims to assess benefits and harms of 4-factor PCC compared to fresh frozen plasma (FFP) or no treatment in VKA associated bleeding. PubMed, EMBASE and CENTRAL were searched from 1945 to August 2015. Studies reporting 4-factor PCC use for VKA associated bleeding and providing data on INR normalization, mortality or thromboembolic (TE) complications were eligible. Two authors screened titles and full articles for inclusion, extracted data, and assessed risk of bias. Mortality data were pooled using Mantel–Haenszel random effects meta-analysis. Nineteen studies were included (N = 2878); 18 cohort studies and one RCT. Six studies had good methodological quality, 9 moderate and 4 poor. Baseline INR values ranged from 2.2 to >20. The INR within 1 h after PCC administration ranged from 1.4 to 1.9, and after FFP administration from 2.2 to 12. PCC reduced the time to reach INR correction in comparison with FFP or no treatment. The observed mortality rate ranged from 0 to 43% (mean 17%) in the PCC, 4.8–54% (mean 16%) in the FFP and 23–69% (mean 51%) in the no treatment group. Meta-analysis of mortality data resulted in an OR of 0.64 (95% confidence interval [CI] 0.27–1.5) for PCC versus FFP and an OR 0.41 (95% CI 0.13–1.3) for PCC versus no treatment. TE complications were observed in 0–18% (mean 2.5%) of PCC and in 6.4% of FFP recipients. Four-factor PCC is an effective and safe option in reversal of VKA bleeding events.

Rationale and design of a phase III safety trial of idarucizumab in children receiving dabigatran etexilate for venous thromboembolism

BACKGROUND

The incidence of venous thromboembolism (VTE) in children has been increasing. Anticoagulants are the mainstay of treatment but are associated with bleeding events that may be life-threatening. Idarucizumab is a fragment antigen-binding (fab) that provides immediate, complete, and sustained reversal of dabigatran's anticoagulant effects in adults.

OBJECTIVE AND METHODS

This phase III, open-label, single-arm, multicenter, multinational trial will assess the safety of idarucizumab in children participating in two ongoing trials investigating dabigatran etexilate. Eligible patients will be children with VTE (aged 0-≤18 years; n = ~5) with life-threatening or uncontrolled bleeding (group A), and children who require emergency surgery/urgent procedures for a condition other than bleeding (group B). Patients will receive idarucizumab up to 5 g as two consecutive intravenous infusions over 5-10 minutes each, as two 10-15-minute drips or as two bolus injections (15 minutes apart) and will be monitored for 30 days. The primary endpoint will be the safety of idarucizumab assessed by the occurrence of drug-related adverse events (including immune reactions) and all-cause mortality. Secondary endpoints will be the reversal of dabigatran anticoagulant effects assessed by changes in diluted thrombin time and ecarin clotting time, time to achieve complete reversal and the duration of the reversal and bleeding severity (group A). The formation of antidrug antibodies at 30 days post-dose and cessation of bleeding will also be assessed.

CONCLUSION

This study will report the safety of idarucizumab in children with VTE who require rapid reversal of the anticoagulant effects of dabigatran. Clinical trial registration: NCT02815670.

Antithrombotic Reversal Agents

The actively bleeding anticoagulated patient presenting to the emergency department requires rapid evaluation and treatment, which is made increasingly complicated by the ever-evolving antithrombotic treatment options used in medicine. Even with excellent supportive care, the timeliness with which reversal decisions need to be made continues to demand of the emergency practitioner a familiarity with the properties and general characteristics of a variety of antithrombotic agents. Reversal options vary and may include vitamin K, FFP, PCC, rFVIIa, platelets, and desmopressin, among others.

The nocturnal acoustical intensity of the intensive care environment: an observational study

BACKGROUND

The intensive care unit (ICU) environment exposes patients to noise levels that may result in substantial sleep disruption. There is a need to accurately describe the intensity pattern and source of noise in the ICU in order to develop effective sound abatement strategies. The objectives of this study were to determine nocturnal noise levels and their variability and the related sources of noise within an Australian tertiary ICU.

METHODS

An observational cross-sectional study was conducted in a 24-bed open-plan ICU. Sound levels were recorded overnight during three nights at 5-s epochs using Extech (SDL 600) sound monitors. Noise sources were concurrently logged by two research assistants.

RESULTS

The mean recorded ambient noise level in the ICU was 52.85 decibels (dB) (standard deviation (SD) 5.89), with a maximum noise recording at 98.3 dB (A). All recorded measurements exceeded the WHO recommendations. Noise variability per minute ranged from 9.9 to 44 dB (A), with peak noise levels >70 dB (A) occurring 10 times/hour (SD 11.4). Staff were identified as the most common source accounting for 35% of all noise. Mean noise levels in single-patient rooms compared with open-bed areas were 53.5 vs 53 dB (p = 0.37), respectively.

CONCLUSION

Mean noise levels exceeded those recommended by the WHO resulting in an acoustical intensity of 193 times greater than the recommended and demonstrated a high degree of unpredictable variability, with the primary noise sources coming from staff conversations. The lack of protective effects of single rooms and the contributing effects that staffs have on noise levels are important factors when considering sound abatement strategies.

Clinical Application of Prothrombin Complex Concentrate in Blood Management in Patients

Management of patients receiving anticoagulants is a major factor in achieving better outcomes. Anticoagulant therapy may need to be discontinued or rapidly reversed before urgent surgery or invasive procedures. In these situations, treatment with concentrated vitamin K, fresh frozen plasma, and/or clotting factors can achieve more rapid anticoagulant reversal than can drug discontinuation alone. Activated prothrombin complex concentrate is used to treat hemophiliac patients with acquired factor VIII inhibitors. Nonactivated prothrombin complex concentrates are used for anticoagulant reversal. The concentrates are effective within minutes of dosing, providing a nearly immediate decrease in the international normalized ratio. The concentrates are lyophilized powders that can be quickly reconstituted, do not require ABO blood typing before use, and contain 25 times the concentration of vitamin K-dependent clotting factors compared with fresh frozen plasma. Studies suggest that the concentrates are associated with better clinical end points than is fresh frozen plasma.

Recombinant Factor VIIa–Mediated Activation of Prothrombin Complex Concentrates

Recombinant factor VIIa (rFVIIa) is used in the management of bleeding in patients with hemophilia. A generic biosimilar version of NovoSeven is also developed (AryoSeven). To compare the activation profile of NovoSeven and AryoSeven, 2 commercially available protein complex concentrates (PCCs) were used. Profilnine activated by RecombiPlasTin 2G resulted in conversions of prothrombin to prethrombin and thrombin at 5 to 30 minutes. However, addition of rFVIIa at final concentration range of 0.25 to 0.5 µg/mL to the same mixture resulted in total conversion of prothrombin to thrombin with a doublet at 36 kDa. Recombinant factor VIIa alone did not generate thrombin in native Beriplex, and the addition of rFVIIa to Beriplex failed to generate thrombin. Beriplex activated by RecombiPlasTin 2G resulted in complete conversion of prothrombin to thrombin. Both NovoSeven and AryoSeven exhibited similar activation profiles. These studies indicate that the activation of PCCs by both rFVIIa preparations results in comparable generation of thrombin.

Brodifacoum Inhalation and its Clinical Manifestations in a 21-Year-Old Caucasian Man

Exposure to brodifacoum, a superwarfarin substance, can lead to severe coagulopathic manifestations. Brodifacoum is a lipophilic, vitamin K antagonist with a long half-life. Clinical manifestations are challenging to diagnose if the patient cannot provide information regarding exposure. Herein, we report the first case in the literature, to our knowledge, of a patient who had intentionally inhaled brodifacoum. We performed coagulation studies such as prothrombin time (PT) and international normalized ratio (INR) to monitor vitamin K dependent coagulation factors in the patient, a 21-year-old Caucasian man. On admission to the hospital, the INR of the patient was 12.9; a computed tomography (CT) angiogram detected a mediastinal hemorrhage. In the absence of 4-factor PCC, the patient received 30 plasma transfusions during a 4-day period due to persistent left pleural effusions, along with vitamin K therapy to normalize his coagulation factors. His high-performance liquid chromatography (HPLC) results on hospital day 3 and day 26 confirmed the presence of brodifacoum in his body. We believe that inhalation led the poison to bypass the initial metabolism process of the liver, resulting in rapid anticoagulation and subsequent bleeding diathesis. Management of brodifacoum poisoning is case dependent on the amount of exposure and INR status. Constant INR monitoring, large dose vitamin K therapy and initial plasma transfusions (in the absence of PCC) were able to prevent severe internal bleeding in the patient.

Prothrombin complex concentrate for reversal of vitamin K antagonist treatment in bleeding and non-bleeding patients

BACKGROUND

Treatment with vitamin K antagonists is associated with increased morbidity and mortality. Reversal therapy with prothrombin complex concentrate (PCC) is used increasingly and is recommended in the treatment of patients with bleeding complications undertaking surgical interventions, as well as patients at high risk of bleeding. Evidence is lacking regarding indication, dosing, efficacy and safety.

OBJECTIVES

We assessed the benefits and harms of PCC compared with fresh frozen plasma in the acute medical and surgical setting involving vitamin K antagonist-treated bleeding and non-bleeding patients. We investigated various outcomes and predefined subgroups and performed sensitivity analysis. We examined risks of bias and applied trial sequential analyses (TSA) to examine the level of evidence, and we prepared a 'Risk of bias' table to test the quality of the evidence.

SEARCH METHODS

We searched the following databases from inception to 1 May 2013: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (Ovid SP); EMBASE (Ovid SP); International Web of Science; Latin American and Caribbean Health Sciences Literature (LILACS) (via BIREME); the Chinese Biomedical Literature Database; advanced Google and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We applied a systematic and sensitive search strategy to identify relevant randomized clinical trials and imposed no language or date restrictions. We adapted our MEDLINE search strategy for searches in all other databases. We reran the search in October 2014 and found one potential new study of interest. We added this study to a list of 'Studies awaiting classification', and we will incorporate this study into the formal review findings at the time of the review update.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), irrespective of publication status, date of publication, blinding status, outcomes published or language. We contacted investigators and study authors to request relevant data.

DATA COLLECTION AND ANALYSIS

Three review authors independently abstracted data and resolved disagreements by discussion. Our primary outcome measures were 'overall mortality longest follow-up' and 'overall 28-day mortality'. We performed subgroup analyses to assess the effects of PCC in adults in terms of various clinical and physiological outcomes. We presented pooled estimates of the effects of interventions on dichotomous outcomes as risk ratios (RRs), and on continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We assessed risk of bias by assessing trial methodological components and risk of random error through TSA.

MAIN RESULTS

We included four RCTs with a total of 453 participants and determined that none of these trials had overall low risk of bias. We found six ongoing trials from which we were unable to retrieve further data. Three trials provided data on mortality. Meta-analysis showed no statistical effect on overall mortality (RR 0.93, 95% CI 0.37 to 2.33; very low quality of evidence). We were unable to associate use of PCC with the number of complications probably related to the intervention (RR 0.92, 95% CI 0.78 to 1.09; very low quality of evidence). Lack of transfusion data and apparent differences in study design prevented review authors from finding a beneficial effect of PCC in reducing the volume of fresh frozen plasma (FFP) transfused to reverse the effect of vitamin K antagonist treatment. The number of new occurrences of transfusion of red blood cells (RBCs) did not seem to be associated with the use of PCC (RR 1.08, 95% CI 0.82 to 1.43; very low quality of evidence). Still, the included studies demonstrate the possibility of equally reversing vitamin K-induced coagulopathy using PCC without the need for transfusion of FFP. No effect on other predefined outcomes was observed.

AUTHORS' CONCLUSIONS

In the four included RCTs, use of prothrombin complex concentrate does not appear to reduce mortality or transfusion requirements but demonstrates the possibility of reversing vitamin K-induced coagulopathy without the need for transfusion of fresh frozen plasma. All included trials have high risk of bias and are underpowered to detect mortality, benefit or harm. Clinical and statistical heterogeneity is high, and definitions of clinically important outcomes such as adverse events are highly dissimilar between trials. Only weak observational evidence currently supports the use of PCC in vitamin K antagonist-treated bleeding and non-bleeding patients, and the current systematic review of RCTs does not support the routine use of PCC over FFP. Additional high-quality research is urgently needed.

Sleeping on a problem: the impact of sleep disturbance on intensive care patients - a clinical review

Sleep disturbance is commonly encountered amongst intensive care patients and has significant psychophysiological effects, which protract recovery and increases mortality. Bio-physiological monitoring of intensive care patients reveal alterations in sleep architecture, with reduced sleep quality and continuity. The etiological causes of sleep disturbance are considered to be multifactorial, although environmental stressors namely, noise, light and clinical care interactions have been frequently cited in both subjective and objective studies. As a result, interventions are targeted towards modifiable factors to ameliorate their impact. This paper reviews normal sleep physiology and the impact that sleep disturbance has on patient psychophysiological recovery, and the contribution that the clinical environment has on intensive care patients' sleep.

Restoration of Normal Prothrombin Time/International Normalized Ratio With Fresh Frozen Plasma in Hypocoagulable Patients

Fresh frozen plasma (FFP) is an effective reversal agent for hypocoagulable patients. Its proven efficacy continues to prompt its usage as both a prophylactic and a therapeutic therapy. Although published guidelines encouraging the appropriate administration of FFP exist, overutilization continues. The purpose of these ex vivo studies was to determine the effects of succeeding volumes of FFP supplementation on hypocoagulable plasma prothrombin time/international normalized ratio (PT/INR). By analyzing the decline in PT/INR with varying volumes of FFP, a minimal required volume of FFP could be identified representing the optimal volume to administer while still providing therapeutic effect. A total of 497 plasma samples were screened for elevated PT/INR values and 50 samples were selected for inclusion in this experiment. The initial PTs/INRs ranged from 12.5 to 43.4 seconds/1.42 to 4.91. Subsequent declines in PT/INR values were analyzed following addition of 50, 100, and 150 µL of FFP to a fixed volume of 250 µL of plasma (26.4 ± 5.318 seconds/2.99 ± 0.603, 13.3 ± 1.077 seconds/1.51 ± 0.122, 11.2 ± 0.712 seconds/1.27 ± 0.081, and 10.3 ± 0.533 seconds/1.16 ± 0.06, respectively). A nonlinear relationship between decline in INR values and percentage of FFP supplementation was demonstrated. The greatest effect on INR was obtained after supplementation with 50 µL (49%). Doubling and tripling the volume of FFP lead to significantly lower declines in INR (16% and 8%, respectively). Analysis of variance indicated a statistical significance with subsequent volume supplementation of FFP, but marginal clinical benefits exist between the PTs/INRs obtainable with increased FFP volume administration.

Guideline-concordant administration of prothrombin complex concentrate and vitamin K is associated with decreased mortality in patients with severe bleeding under vitamin K antagonist treatment (EPAHK study)

Introduction

In vitamin K antagonist (VKA)-treated patients with severe hemorrhage, guidelines recommend prompt VKA reversal with prothrombin complex concentrate (PCC) and vitamin K. The aim of this observational cohort study was to evaluate the impact of guideline concordant administration of PCC and vitamin K on seven-day mortality.

Methods

Data from consecutive patients treated with PCC were prospectively collected in 44 emergency departments. Type of hemorrhage, coagulation parameters, type of treatment and seven-day mortality mortality were recorded. Guideline-concordant administration of PCC and vitamin K (GC-PCC-K) were defined by at least 20 IU/kg factor IX equivalent PCC and at least 5 mg of vitamin K performed within a predefined time frame of eight hours after admission. Multivariate analysis was used to assess the effect of appropriate reversal on seven-day mortality in all patients and in those with intracranial hemorrhage (ICH).

Results

Data from 822 VKA-treated patients with severe hemorrhage were collected over 14 months. Bleeding was gastrointestinal (32%), intracranial (32%), muscular (13%), and “other” (23%). In the whole cohort, seven-day mortality was 13% and 33% in patients with ICH. GC-PCC-K was performed in 38% of all patients and 44% of ICH patients. Multivariate analysis showed a two-fold decrease in seven-day mortality in patients with GC-PCC-K (odds ratio (OR) = 2.15 (1.20 to 3.88); P = 0.011); this mortality reduction was also observed when only ICH was considered (OR = 3.23 (1.53 to 6.79); P = 0.002).

Conclusions

Guideline-concordant VKA reversal with PCC and vitamin K within eight hours after admission was associated with a significant decrease in seven-day mortality.

Management of dabigatran-associated intracerebral and intraventricular hemorrhage: a case report

BACKGROUND

Dabigatran is an oral, reversibly bound, direct thrombin inhibitor currently approved in the United States for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. In the phase III trial leading to approval of the agent, the incidence of life-threatening bleeding was 1.80%/year in the dabigatran 150 mg twice daily arm. Because there is no direct antidote or reversal agent for this drug, the need to manage life-threatening hemorrhages with procoagulant products will arise.

OBJECTIVE

To describe a case of dabigatran-associated intracerebral and intraventricular hemorrhage and subsequent management with activated prothrombin complex concentrate.

CASE REPORT

An 85-year-old man currently taking dabigatran 150 mg twice daily presented to the Emergency Department for incoordination, expressive aphasia, and weakness. A computed tomography image of his head demonstrated an intracranial hemorrhage. The last dose of dabigatran was approximately 14 h prior to arrival, and conventional coagulation assays (thrombin time and activated partial thromboplastin time) confirmed the presence of dabigatran in the patient's serum. The patient received 27.5 units/kg of activated prothrombin complex concentrate (FEIBA®; Baxter Healthcare Corporation, Deerfield, IL) after an initial intravenous fluid bolus. His activated partial thromboplastin time was not completely normalized by the use of FEIBA; however, the patient's neurological examination slightly improved and remained stable throughout his hospital course despite some intraventricular expansion of the hematoma. After discharge to physical rehabilitation, the patient developed an ischemic cerebrovascular accident and was discharged home on hospice.

CONCLUSION

Due to lack of an available antidote, activated prothrombin complex concentrate was utilized as a nonspecific procoagulant to stabilize an intracerebral hemorrhage in a patient on dabigatran.

Compositional Differences in Commercially Available Prothrombin Complex Concentrates

Prothrombin complex concentrates (PCCs) are used in the management of bleeding complications with conventional oral anticoagulant drugs. Since the activation of these complexes results in the generation of factor Xa and IIa, these agents may potentially neutralize the newly developed Xa and thrombin inhibitors. Although the potency of these agents is defined in units that represent the level of factor IX (FIX), other factors including factor II, VII, and X are also present. Protein C, protein S, and protein Z are also present. The purpose of this study is to compare the compositional differences in the currently available PCCs along with the older agents. Measurement of compositional parameters including protein and FIX, mass spectrometric analysis of the native and activated PCCs, Western blotting studies on the native and activated PCCs for the activation products including thrombin, and their effect on blood and plasma coagulation parameters were carried out.

Efficacy and safety of a 4-factor prothrombin complex concentrate in patients on vitamin K antagonists presenting with major bleeding: a randomized, plasma-controlled, phase IIIb study

BACKGROUND

Patients experiencing major bleeding while taking vitamin K antagonists require rapid vitamin K antagonist reversal. We performed a prospective clinical trial to compare nonactivated 4-factor prothrombin complex concentrate (4F-PCC) with plasma for urgent vitamin K antagonist reversal.

METHODS AND RESULTS

In this phase IIIb, multicenter, open-label, noninferiority trial, nonsurgical patients were randomized to 4F-PCC (containing coagulation factors II, VII, IX, and X and proteins C and S) or plasma. Primary analyses examined whether 4F-PCC was noninferior to plasma for the coprimary end points of 24-hour hemostatic efficacy from start of infusion and international normalized ratio correction (≤1.3) at 0.5 hour after end of infusion. The intention-to-treat efficacy population comprised 202 patients (4F-PCC, n=98; plasma, n=104). Median (range) baseline international normalized ratio was 3.90 (1.8-20.0) for the 4F-PCC group and 3.60 (1.9-38.9) for the plasma group. Effective hemostasis was achieved in 72.4% of patients receiving 4F-PCC versus 65.4% receiving plasma, demonstrating noninferiority (difference, 7.1% [95% confidence interval, -5.8 to 19.9]). Rapid international normalized ratio reduction was achieved in 62.2% of patients receiving 4F-PCC versus 9.6% receiving plasma, demonstrating 4F-PCC superiority (difference, 52.6% [95% confidence interval, 39.4 to 65.9]). Assessed coagulation factors were higher in the 4F-PCC group than in the plasma group from 0.5 to 3 hours after infusion start (P<0.02). The safety profile (adverse events, serious adverse events, thromboembolic events, and deaths) was similar between groups; 66 of 103 (4F-PCC group) and 71 of 109 (plasma group) patients experienced ≥1 adverse event.

CONCLUSIONS

4F-PCC is an effective alternative to plasma for urgent reversal of vitamin K antagonist therapy in major bleeding events, as demonstrated by clinical assessments of bleeding and laboratory measurements of international normalized ratio and factor levels.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00708435.

Rapid reversal of warfarin-associated hemorrhage in the emergency department by prothrombin complex concentrates

Life-threatening warfarin-associated hemorrhage is common, with a high mortality. In the United States, the most commonly used therapies--fresh frozen plasma and vitamin K--are slow and unpredictable and can result in volume overload. Outside of the United States, prothrombin complex concentrates are often used instead; these pooled plasma products reverse warfarin anticoagulation in minutes rather than hours. This article reviews the literature relating to warfarin reversal with fresh frozen plasma, prothrombin complex concentrates, and recombinant factor VIIa and provides elements for a management protocol based on this literature.

Current State of Knowledge on Oral Anticoagulant Reversal Using Procoagulant Factors

OBJECTIVE:

To discuss current trends and challenges in the use of procoagulants for treating bleeding caused by use of oral anticoagulants.

DATA SOURCES:

Literature searches of PubMed (MEDLINE), Google, and Medscape were conducted in February 2013. There were no date limitations. Search terms included anticoagulation agents, anticoagulation reversal, anticoagulation reversal agents, apixaban, clinical studies, dabigatran, 3-factor PCCs, 4-factor PCCs, FEIBA, fresh frozen plasma, human studies, pharmacology, prescribing information, rFVIIa, rivaroxaban, vitamin K, and warfarin.

DATA SYNTHESIS:

Warfarin has been the mainstay for the treatment and prevention of primary and secondary thrombosis in patients with cardiovascular disorders such as atrial fibrillation, deep vein thrombosis, pulmonary embolism, and stroke. Three oral anticoagulants have recently become available in the US: a direct thrombin inhibitor, dabigatran etexilate, and 2 direct factor Xa inhibitors, rivaroxaban and apixaban. Reversal strategies for anticoagulant-associated bleeding are well established for warfarin; however, strategies to stop bleeding in a patient who has taken one of the newer anticoagulants are less clear. In the US, agents available for oral anticoagulant reversal include activated prothrombin complex concentrate (APCC), 3-factor PCCs, and recombinant activated factor VII (rFVIIa). Few studies have evaluated the 3-factor PCCs, and current evidence for APCC and rFVIIa as reversal agents for dabigatran and rivaroxaban is based primarily on laboratory or animal studies, or on small studies in healthy humans and case reports.

CONCLUSIONS:

Patients contemplating using the new oral anticoagulants should be informed about specific clinical situations that could pose a bleeding risk such as the need for emergency surgery because no reliable antidote is available to stop the bleeding, which could prove fatal.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: « Does this particular AABT reduce the transfusion rate or not?» All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: "Does this particular AABT reduce the transfusion rate or not?" All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

[Reversal for heparins and new anticoagulant treatments]

Even with unfractionated heparin or derivates, the reversal of pharmacologic anticoagulation is crucial in anticoagulated patients developing a life-threatening bleeding or scheduled for an emergency procedure. The antagonisation of unfractionated heparin is well codified: each milligram of protamine sulfate antagonizes 100 IU of heparin. Measurement of thrombin time reflects the anti-IIa effect of heparin and has to be monitored immediately and 1hour after the injection of protamine. The required dose of protamine sulfate depends on dosage and time of LMWH administration, although no clinical study supports these data. To date, there is no effective antidote for new anticoagulants (fondaparinux and other pentasaccharides, direct thrombin inhibitors, direct anti-Xa inhibitors). Some preliminary studies suggest the effectiveness of recombinant activated factor VII for pentasaccharides and activated or not Prothrombin Complex Concentrates and recombinant activated factor VII for oral anti-Xa and anti-IIa agents. Therefore, while the characteristics of these new anticoagulants could increase the comfort and improve the compliance, their development needs to ascertain the lack of increase in bleeding complications and the need for a safe and effective antidote.

Reversal of Vitamin K Antagonist (VKA) effect in patients with severe bleeding: a French multicenter observational study (Optiplex) assessing the use of Prothrombin Complex Concentrate (PCC) in current clinical practice

Introduction

Prothrombin Complex Concentrate (PCC) is a key treatment in the management of bleeding related to Vitamin K antagonists (VKA). This study aimed to evaluate prospectively PCC use in patients with VKA-related bleeding in view of the French guidelines published in 2008.

Methods

All consecutive patients with VKA-related bleeding treated with a 4-factor PCC (Octaplex^®) were selected in 33 French hospitals. Collected data included demographics, site and severity of bleeding, modalities of PCC administration, International Normalized Ratio (INR) values before and after PCC administration, outcomes and survival rate 15 days after infusion.

Results

Of 825 patients who received PCC between August 2008 and December 2010, 646 had severe bleeding. The main haemorrhage sites were intracranial (43.7%) and abdominal (24.3%). Mean INR before PCC was 4.4 ± 1.9; INR was unavailable in 12.5% of patients. The proportions of patients who received a PCC dose according to guidelines were 15.8% in patients with initial INR 2-2.5, 41.5% in patients with INR 2.5-3, 40.8% in patients with INR 3-3.5, 26.9% in patients with INR > 3.5, and 63.5% of patients with unknown INR. Vitamin K was administered in 84.7% of patients. The infused dose of PCC did not vary with initial INR; the mean dose was 25.3 ± 9.8 IU/Kg. Rates of controlled bleeding and target INR achievement were similar, regardless of whether or not patients were receiving PCC doses as per the guidelines. No differences in INR after PCC treatment were observed, regardless of whether or not vitamin K was administered. INR was first monitored after a mean time frame of 4.5 ± 5.6 hours post PCC. The overall survival rate at 15 days after PCC infusion was 75.4% (65.1% in patients with intracranial haemorrhage). A better prognosis was observed in patients reaching the target INR.

Conclusions

Severe bleeding related to VKA needs to be better managed, particularly regarding the PCC infused dose, INR monitoring and administration of vitamin K. A dose of 25 IU/kg PCC appears to be efficacious in achieving a target INR of 1.5. Further studies are required to assess whether adjusting PCC dose and/or better management of INR would improve outcomes.

Emergency management of bleeding associated with old and new oral anticoagulants

As major prescribers of oral anticoagulants, cardiologists must be familiar with strategies to manage bleeding, the principal complication associated with all anticoagulants, and to reverse anticoagulant effects in acute-care settings. The purpose of this manuscript is to review currently available information regarding dabigatran and rivaroxaban, the 2 novel oral anticoagulants approved to date in the United States. Further, we suggest reasonable interventions for the clinician faced with a patient who suffers a major bleeding event while receiving one of these agents. Data sources were peer-reviewed publications, US Food and Drug Administration documents in the public domain, and approved US prescribing information for dabigatran (Pradaxa) and rivaroxaban (Xarelto). Strategies for management of bleeding and reversal of anticoagulant effects from warfarin include vitamin K, fresh frozen plasma, and prothrombin complex concentrates. For rivaroxaban and dabigatran, appropriate therapies include support and observation, which are likely to be effective for the majority of patients because of the short half-lives of these agents. In severe life-threatening hemorrhage, clotting-factor substitutes may be appropriate in certain situations. Validated protocols specific to each agent remain to be developed.

Treatment of warfarin-associated coagulopathy with vitamin K

Warfarin is the most common form of oral anticoagulant therapy. Although it has indisputable benefit in the management of thromboembolic disease, warfarin-associated coagulopathy (WAC) is a well-documented complication of its use. As warfarin exerts its effect by impairing formation of the vitamin K-dependent clotting factors, a cornerstone of WAC management is vitamin K replacement. Daily vitamin K supplementation is an emerging approach to regulate international normalized ratios in difficult-to-control patients. Mild WAC without bleeding can often be managed with warfarin withdrawal alone. For excessive international normalized ratio elevation in the absence of bleeding, low-dose oral vitamin K (1?2.5 mg) is sufficient and achieves the same degree of international normalized ratio correction by 24 h as intravenous therapy. The stable patient with WAC and minor bleeding can also be given oral vitamin K, with correction of the underlying defect. Major bleeding should first be managed with factor replacement for immediate correction of the coagulopathy, using either a prothrombin complex concentrate or fresh-frozen plasma. High-dose vitamin K (10 mg) should be given concurrently via intravenous infusion to confer lasting correction. Warfarin resistance and vitamin K-associated anaphylaxis are rare. Despite development of new oral anticoagulant therapy compounds, warfarin will probably retain a prominent role in thromboembolism management for several years to come.

Reduction of Fresh Frozen Plasma Requirements by Perioperative Point-of-Care Coagulation Management with Early Calculated Goal-Directed Therapy

BACKGROUND: Massive bleeding and transfusion of packed red blood cells (PRBC), fresh frozen plasma (FFP) and platelets are associated with increased morbidity, mortality and costs. PATIENTS AND METHODS: We analysed the transfusion requirements after implementation of point-of-care (POC) coagulation management algorithms based on early, calculated, goal-directed therapy with fibrinogen concentrate and prothrombin complex concentrate (PCC) in different perioperative settings (trauma surgery, visceral and transplant surgery (VTS), cardiovascular surgery (CVS) and general and surgical intensive care medicine) at 3 different hospitals (AUVA Trauma Centre Salzburg, University Hospital Innsbruck and University Hospital Essen) in 2 different countries (Austria and Germany). RESULTS: In all institutions, the implementation of POC coagulation management algorithms was associated with a reduction in the transfusion requirements for FFP by about 90% (Salzburg 94%, Innsbruck 88% and Essen 93%). Furthermore, PRBC transfusion was reduced by 8.4-62%. The incidence of intraoperative massive transfusion (≥10 U PRBC) could be more than halved in VTS and CVS (2.56 vs. 0.88%; p < 0.0001 and 2.50 vs. 1.06%; p = 0.0007, respectively). Platelet transfusion could be reduced by 21-72%, except in CVS where it increased by 115% due to a 5-fold increase in patients with dual antiplatelet therapy (2.7 vs. 13.7%; p < 0.0001). CONCLUSIONS: The implementation of perioperative POC coagulation management algorithms based on early, calculated, goal-directed therapy with fibrinogen concentrate and PCC is associated with a reduction in the transfusion requirements for FFP, PRBC and platelets as well as with a reduced incidence of massive transfusion. Thus, the limited blood resources can be used more efficiently.

Study of Octaplex dosing accuracy: an in vitro analysis

Prothrombin complex concentrates (PCC) are recommended for urgent warfarin reversal. However, disagreement exists regarding the proper dosing strategy (i.e. fixed vs. weight-based). We measured the in vitro effect of PCC dosing on international normalised ratio (INR) and factor activity. Plasma from warfarin-anticoagulated patients with stable INRs was collected. PCC doses of 1,000, 2,000 and 3,000 IU were added to the samples, and INR and factor activity were analysed before and after PCC. Twenty-three of thirty subjects enrolled had complete data for analysis. INRs were below 1.5 in all samples post-1,000 IU, and decreased further with subsequent doses (p<0.001). Factors II, VII, and X increased with consecutive doses (p<0.01). Linear correlation was seen between INR and factors II, VII and X. Factor IX did not increase consistently nor show correlation with INR reversal. Weight-based dosing was then estimated; INRs were all <1.2 (0.9-1.2) and activity >0.50 IU for factors II, VII and X (0.96-1.52, 0.51-1.45 and 0.81-1.38, respectively). Factor IX did not uniformly correct above 0.50 IU (0.31-1.31). We confirm in vitro that 1,000 IU of Octaplex(®) is able to correct INR to <1.5 but factors were not uniformly >0.50 IU until 2,000 IU, and not >1.00 IU until 3,000 IU. This suggests that INR correction alone may not accurately reflect factor activity, and lends support for weight-based dosing.

Prophylactic correction of the international normalized ratio in neurosurgery: a brief review of a brief literature

Prophylactic fresh-frozen plasma (FFP) transfusion is often undertaken in hemodynamically stable patients with a minimally elevated international normalized ratio (INR) prior to invasive procedures, despite little evidence in support of this practice. The authors review the current literature in an attempt to clarify best clinical practice with regard to this issue. Although the activated partial thromboplastin time and prothrombin time–INR are useful laboratory tests to measure specific clotting factors in the coagulation cascade, in the absence of active bleeding or a preexisting coagulopathy, their utility as predictors of overall bleeding risk is limited. Several studies have shown an imperfect correlation between mild elevations in the INR and subsequent bleeding tendency. Furthermore, FFP transfusion is not always sufficient to achieve normal INR values in patients who have mild elevations (< 2) to begin with. Finally, there are risks associated with FFP transfusion, including potential transfusion-associated [disease] exposures as well as the time delay imposed by laboratory testing and transfusion administration prior to initiation of procedures. The authors propose that the current concept of a “normal” INR value warrants redefinition to make it a more meaningful clinical tool. Based on their review of the literature, the authors suggest that in a hemodynamically stable patient population there is a range of mildly prolonged INR values for which FFP transfusion is not beneficial, and is potentially harmful.

Coagulation management in massive bleeding

PURPOSE OF REVIEW

To update readers on recent literature regarding treatment of coagulopathy for patients with life-threatening bleeding, highlighting emerging therapeutic options, controversial topics, and ongoing clinical trials.

RECENT FINDINGS

Massive transfusion protocols featuring immediate availability of blood products and multidisciplinary communication reduce mortality and conserve resources. There is a growing consensus that immediate administration of plasma and platelet units in a 1: 1: 1 ratio with red cell units reduces early mortality. Lyophilized and recombinant blood product components may have advantages over traditional blood products in certain clinical circumstances.

SUMMARY

Massive transfusion protocols standardize treatment of the coagulopathy of massive bleeding, leading to rapid restoration of hemostasis and decrease in early mortality.