Identifying hemophilia B carriers: Utility of aPTT, factor IX levels and ratios of factor IX to other Vitamin K dependent factors.

INTRODUCTION: Diagnosing hemophilia B (HB) carrier status is important to manage bleeding in carriers and to prevent bleeding in potential offspring. Without a family history of hemophilia, diagnosing HB carrier status is challenging. Genetic testing is the gold-standard, however it is reserved for individuals with a high suspicion of carrier status. AIMS: To describe the distribution of activated partial thromboplastin time (aPTT) and factor IX coagulant (FIX:C) levels in HB carriers and assess the ratio of FIX:C to other Vitamin K dependent factors (FII:C, FVII:C, FX:C) as an indicator of HB carrier status. METHODS: In this retrospective, single-centre cohort study, subjects were included if they were obligate or genetically proven HB carriers. Distributions of aPTT and FIX:C were described and the relationship between FIX:C levels in carriers and severity of familial HB was analysed. Ratios of FIX:C to FII:C, FVII:C, FX:C were calculated. RESULTS: Seventy-two female HB carriers (median age: 34 years; IQR 24-43) were included. Median aPTT and FIX:C levels were 33.0 s [IQR 30.0-37.0] and 57 IU/dL [IQR 43-74]. Fifteen carriers (21%) had mild HB (FIX:C levels of 10-40 IU/dL). FIX:C levels trended higher in carriers of mild HB versus carriers of moderate/severe HB. In six carriers, the median ratio of FIX:C to other Vitamin K dependent factors was 0.44, with 92% of ratios being ≤ 0.75. CONCLUSION: aPTT and FIX:C levels were unreliable in diagnosing HB carrier status. A low ratio of FIX:C to other Vitamin K dependent factors may be a useful marker of HB carrier status.

SARS-CoV-2 S protein activates NLRP3 inflammasome and deregulates coagulation factors in endothelial and immune cells.

BACKGROUND: Hyperinflammation, hypercoagulation and endothelial injury are major findings in acute and post-COVID-19. The SARS-CoV-2 S protein has been detected as an isolated element in human tissues reservoirs and is the main product of mRNA COVID-19 vaccines. We investigated whether the S protein alone triggers pro-inflammatory and pro-coagulant responses in primary cultures of two cell types deeply affected by SARS-CoV-2, such are monocytes and endothelial cells. METHODS: In human umbilical vein endothelial cells (HUVEC) and monocytes, the components of NF-κB and the NLRP3 inflammasome system, as well as coagulation regulators, were assessed by qRT-PCR, Western blot, flow cytometry, or indirect immunofluorescence. RESULTS: S protein activated NF-κB, promoted pro-inflammatory cytokines release, and triggered the priming and activation of the NLRP3 inflammasome system resulting in mature IL-1ß formation in both cell types. This was paralleled by enhanced production of coagulation factors such as von Willebrand factor (vWF), factor VIII or tissue factor, that was mediated, at least in part, by IL-1ß. Additionally, S protein failed to enhance ADAMTS-13 levels to counteract the pro-coagulant activity of vWF multimers. Monocytes and HUVEC barely expressed angiotensin-converting enzyme-2. Pharmacological approaches and gene silencing showed that TLR4 receptors mediated the effects of S protein in monocytes, but not in HUVEC. CONCLUSION: S protein behaves both as a pro-inflammatory and pro-coagulant stimulus in human monocytes and endothelial cells. Interfering with the receptors or signaling pathways evoked by the S protein may help preventing immune and vascular complications driven by such an isolated viral element. Video Abstract.

Recombinant factor IX Fc for the treatment of hemophilia B.

Current hemophilia B treatment guidelines recommend routine prophylaxis with factor IX (FIX) replacement products, tailored to maintain plasma activity at levels that will prevent bleeds. However, plasma FIX activity may not be the primary determinant or best indicator of hemostatic efficacy due to its extravascular distribution. FIX replacement therapy has evolved to include extended half-life (EHL) products that provide effective bleed protection when administered at intervals of 7 days or longer. rFIXFc is a recombinant fusion protein with an extended circulation time. rFIXFc has a biodistribution profile consistent with distribution into extravascular space, where it may support hemostasis at sites of vessel injury independent of circulating plasma activity levels. The safety and efficacy of rFIXFc prophylaxis is well established in adults, adolescents and children including previously untreated patients with hemophilia B, with substantial evidence from clinical trials and real-world clinical practice. This review describes the pharmacokinetic characteristics of rFIXFc, summarizes available safety and efficacy data, and evaluates the use of rFIXFc in special populations. Current hemophilia B treatment challenges, including target FIX plasma levels, perioperative use, and management of patients with comorbidities, are discussed together with the potential role of EHL products in the future treatment landscape of hemophilia B.

[Haemophilia B therapy: impact of the reimbursability of a long-acting recombinant factor on pharmaceutical expenditure in Italy]. / Terapia dell'emofilia B: impatto dell'ammissione alla rimborsabilità di un fattore ricombinante long-acting sulla spesa farmaceutica in Italia.

OBJECTIVES: to assess the variability in expenditure compared to 2022 assuming different rates of shifting of therapy days from current active ingredients used for the treatment of haemophilia B to nonacog beta pegolDesign: descriptive cross-sectional study. SETTING AND PARTICIPANTS: consumption in the year 2022 (data source: Medicines Utilisation Monitoring Centre, Italian Medicines Agency) of all medicinal products available in Italy containing coagulation factor IX. MAIN OUTCOMES MEASURES: for each active ingredient, the total number of therapy days and the variability in expenditure compared to 2022 were estimated on the basis of a switch of therapy days, between 5% and 20%, to nonacog beta pegol. RESULTS: on the basis of considered scenarios, the analysis shows that the total annual expenditure for clotting factors used in the treatment of haemophilia B could remain at most unchanged or reduced. Particularly, the extent of the reduction in spending could vary from 0.11% to 2.26%. This trend would be in contrast to the stable increase seen in recent years, particularly in 2022. CONCLUSIONS: this predictive spending assessment may be useful in evaluating the economic impact from new treatment options, such as etranacogene dezaparvovec gene therapy already approved by the European Medicines Agency and the Food and Drug Administration, and to improve pharmaceutical governance.

A phase 1b/2 clinical study of marstacimab, targeting human tissue factor pathway inhibitor, in haemophilia.

A phase 1b/2, three-month study of marstacimab, a human monoclonal antibody targeting tissue factor pathway inhibitor (TFPI), was conducted in participants with haemophilia A or B, with or without inhibitors. Participants assigned to four cohorts received escalating weekly doses based on inhibitor status (without inhibitors: 300 mg, a single 300-mg loading dose with subsequent 150-mg doses, or 450 mg; with inhibitors: 300 mg). Safety outcomes were treatment-emergent adverse events (TEAEs), injection site reactions, clinical and laboratory parameter changes. Efficacy was assessed by annualised bleeding rates (ABRs). Pharmacokinetics and pharmacodynamics (PD) were also evaluated. Among 26 treated participants [haemophilia A without inhibitor, n = 16 (61.5%); haemophilia A with inhibitor, n = 7 (26.9%); haemophilia B, n = 3 (11.5%)], 24 completed the study. Overall, 80.8% experienced TEAEs. ABR during treatment was significantly reduced versus an external on-demand control group (p < 0.0001) and versus pretreatment ABR (p < 0.0001), with significant reductions observed across all dose cohorts. Marstacimab exposure generally increased in a dose-related manner, with steady-state concentration reached by day 57. Changes in pharmacodynamic biomarkers occurred across all dose cohorts. Marstacimab was safe and well tolerated. Clinically meaningful reductions in ABR and treatment-related changes for all PD biomarkers indicated effective targeting of TFPI. (Clinicaltrials.gov identifier, NCT02974855).

Prothrombin complex concentrate (PCC) for treatment of trauma-induced coagulopathy: systematic review and meta-analyses.

BACKGROUND: Trauma-induced coagulopathy (TIC) is common in trauma patients with major hemorrhage. Prothrombin complex concentrate (PCC) is used as a potential treatment for the correction of TIC, but the efficacy, timing, and evidence to support its use in injured patients with hemorrhage are unclear. METHODS: A systematic search of published studies was performed on MEDLINE and EMBASE databases using standardized search equations. Ongoing studies were identified using clinicaltrials.gov. Studies investigating the use of PCC to treat TIC (on its own or in combination with other treatments) in adult major trauma patients were included. Studies involving pediatric patients, studies of only traumatic brain injury (TBI), and studies involving only anticoagulated patients were excluded. Primary outcomes were in-hospital mortality and venous thromboembolism (VTE). Pooled effects of PCC use were reported using random-effects model meta-analyses. Risk of bias was assessed for each study, and we used the Grading of Recommendations Assessment, Development, and Evaluation to assess the quality of evidence. RESULTS: After removing duplicates, 1745 reports were screened and nine observational studies and one randomized controlled trial (RCT) were included, with a total of 1150 patients receiving PCC. Most studies used 4-factor-PCC with a dose of 20-30U/Kg. Among observational studies, co-interventions included whole blood (n = 1), fibrinogen concentrate (n = 2), or fresh frozen plasma (n = 4). Outcomes were inconsistently reported across studies with wide variation in both measurements and time points. The eight observational studies included reported mortality with a pooled odds ratio of 0.97 [95% CI 0.56-1.69], and five reported deep venous thrombosis (DVT) with a pooled OR of 0.83 [95% CI 0.44-1.57]. When pooling the observational studies and the RCT, the OR for mortality and DVT was 0.94 [95% CI 0.60-1.45] and 1.00 [95% CI 0.64-1.55] respectively. CONCLUSIONS: Among published studies of TIC, PCCs did not significantly reduce mortality, nor did they increase the risk of VTE. However, the potential thrombotic risk remains a concern that should be addressed in future studies. Several RCTs are currently ongoing to further explore the efficacy and safety of PCC.

Use of four-factor prothrombin complex concentrate (4F-PCC) for management of bleeding not associated with therapeutic anticoagulant use.

INTRODUCTION: Four-factor prothrombin complex concentrate (4F-PCC) may be an option for patients with bleeding unrelated to therapeutic anticoagulation to help with bleeding cessation and reduce blood component requirements. MATERIALS AND METHODS: Retrospective, observational study of adult patients who received 4F-PCC for bleeding not associated with therapeutic anticoagulation between June 2019 and July 2021. Primary outcome was to describe off-label 4F-PCC use in patients not on therapeutic anticoagulation for bleeding management in surgical and non-surgical patients. Additional outcomes evaluated were blood product use, chest tube and drainage output, and coagulation studies before and after 4F-PCC administration as well as other hemostatic agent use and thromboembolic events. RESULTS: Seventy-six patients were included; median age 64 years (IQR 50-69), 66% of bleeding events were associated with surgery, and the majority of 4F-PCC doses ordered by cardiac surgery (68.4%). A total of 110 4F-PCC doses were administered; median 1 dose/patient (IQR 1-2), median total dose 1000 units (IQR 500-1484). Other hemostatic agents commonly administered were protamine (59%), desmopressin (43%), and tranexamic acid (42%). Packed red blood cells, fresh frozen plasma, platelet, and cell saver blood administration and prothrombin time (PT), international normalized ratio (INR), and partial thromboplastin time (aPTT) were significantly reduced following 4F-PCC administration. Eight patients (11%) experienced thromboembolic complications. CONCLUSION: Relatively low doses of 4F-PCC (median total dose 1000 units) were associated with decreased blood component requirements and improved PT, INR, and aPTT values in patients with bleeding unrelated to therapeutic anticoagulation. Other hemostatic agent use was common and thromboembolic complications occurred.

Incidence of thrombotic complications related to weight-based dosing of activated prothrombin complex concentrate (aPCC) for reversal of apixaban and rivaroxaban in obese patients.

Factor eight inhibitor bypassing activity (aPCC) is recommended as a non-specific reversal agent for direct oral anticoagulants (DOACs) according to the 2017 American College of Cardiology (ACC) guidelines for reversal of anticoagulation. Factor eight inhibitor bypassing activity carries a black box warning for thrombotic events such as stroke, pulmonary embolism, deep vein thrombosis, and myocardial infarction, particularly at high doses. This was a retrospective, single-center, cohort investigation that included patients who received a weight-based dose of aPCC for reversal of apixaban and rivaroxaban between January 1, 2015, and December 31, 2020. Patients were grouped by BMI as obese (BMI ≥ 30 kg/m2) or non-obese (BMI < 30 kg/m2) for analysis. The primary outcome of this investigation was the occurrence of thrombotic complications [venous thromboembolism (VTE), myocardial infarction, stroke] documented in the medical record at any point during hospitalization after administration of aPCC. Secondary outcomes included bleeding complications, in-hospital mortality, ICU and hospital length of stay. Patients in the obese group were younger [76.4 years (SD +/- 11.3 years) vs. 69.6 years (SD +/- 12.4 years); p < 0.0001] and a higher proportion had a diagnosis of diabetes mellitus prior to admission [37 (19.2%) vs. 35 (36.8%); p = 0.0011]. There was no difference in the primary outcome of thrombotic events between non-obese and obese patients [12 (6.2%) vs. 5 (5.3%); p = 0.75], or for any of the secondary outcomes of bleeding, in-hospital mortality or length of stay. This investigation did not reveal a difference in rates of thrombosis or bleeding events between obese and non-obese patients who received aPCC for reversal of apixaban and rivaroxaban.

Comparison of 3-factor versus 4-factor prothrombin complex concentrate for emergent warfarin reversal: a systematic review and meta-analysis.

BACKGROUND: Patients requiring emergent warfarin reversal (EWR) have been prescribed three-factor prothrombin complex concentrate (PCC3) and four-factor prothrombin complex concentrate (PCC4) to reverse the anticoagulant effects of warfarin. There is no existing systematic review and meta-analysis of studies directly comparing PCC3 and PCC4. METHODS: The primary objective of this systematic review and meta-analysis was to determine the effectiveness of achieving study defined target INR goal after PCC3 or PCC4 administration. Secondary objectives were to determine the difference in safety endpoints, thromboembolic events (TE), and survival during the patients' hospital stay. Random-effects meta-analysis models were used to estimate the odds ratios (OR), and heterogeneity associated with the outcomes. The Newcastle-Ottawa Scale was used to assess study quality, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. RESULTS: Ten full-text manuscripts and five abstracts provided data for the primary and secondary outcomes. Patients requiring EWR had more than three times the odds of reversal to goal INR when they were given PCC4 compared to PCC3 (OR = 3.61, 95% CI: 1.97-6.60, p < 0.001). There was no meaningful clinical association or statistically significant result between PCC4 and PCC3 groups in TE (OR = 1.56, 95% CI: 0.83-2.91, p = 0.17), or survival during hospital stay (OR = 1.34, 95% CI: 0.81-2.23, p = 0.25). CONCLUSION: PCC4 is more effective than PCC3 in meeting specific predefined INR goals and has similar safety profiles in patients requiring emergent reversal of the anticoagulant effects of warfarin.

The association of prothrombin complex concentrates with postoperative outcomes in cardiac surgery: an observational substudy of the FIBRES randomized controlled trial.

PURPOSE: The mainstay of therapy for coagulation factor deficiency in cardiac surgical patients is frozen plasma (FP); however, prothrombin complex concentrates (PCCs) may offer logistical and safety advantages. As there is limited comparative evidence, we conducted this study to explore the association of comparable PCC or FP doses with transfusion and outcomes. METHODS: This was a post hoc analysis of a multicentre randomized trial comparing fibrinogen concentrate with cryoprecipitate (FIBRES trial) in bleeding cardiac surgical patients. This analysis included 415 patients who received only PCC (n = 72; 17%) or only FP (n = 343; 83%) for factor replacement. The main outcomes of interest were red blood cell (RBC) and platelet transfusion within 24 hr of cardiopulmonary bypass. Secondary outcomes included postoperative adverse events. Associations were examined by hierarchical generalized estimating equation models adjusted for demographic and surgical characteristics. RESULTS: The median [interquartile range (IQR)] PCC dose was 1,000 [1,000-2,000] units, while the median [IQR] FP dose was 4 [2-6] units. Each unit of FP was independently associated with increased adjusted odds of RBC (1.60; 95% confidence interval [CI], 1.36 to 1.87; P < 0.01) and platelet transfusion (1.40; 95% CI, 1.15 to 1.69; P < 0.01) while each 500 units of PCC was independently associated with reduced adjusted odds of RBC (0.67; 95% CI, 0.50 to 0.90; P < 0.01) and platelet transfusion (0.80; 95% CI, 0.70 to 0.92; P < 0.01). Adverse event rates were comparable. CONCLUSIONS: In cardiac surgical patients with post-cardiopulmonary bypass bleeding, PCC use was associated with lower RBC and platelet transfusion than FP use was. Prospective, randomized clinical trials comparing FP with PCC in this setting are warranted.

RéSUMé: OBJECTIF: Le pilier du traitement du déficit en facteur de coagulation chez les patients de chirurgie cardiaque est le plasma congelé (PC); cependant, les concentrés de complexe prothrombinique (CCP) peuvent offrir des avantages en matière de logistique et de sécurité. Comme il existe peu de données probantes comparatives, nous avons réalisé cette étude pour explorer l'association de doses comparables de CCP ou de PC avec la transfusion et les issues postopératoires. MéTHODE: Il s'agit d'une analyse post-hoc d'une étude randomisée multicentrique comparant le concentré de fibrinogène au cryoprécipité (étude FIBRES) chez des patients avec hémorragies en chirurgie cardiaque. Cette analyse a inclus 415 patients qui n'ont reçu que du CCP (n = 72; 17 %) ou du PC (n = 343; 83 %) pour le remplacement des facteurs. Les principaux critères d'évaluation étaient la transfusion d'érythrocytes et de plaquettes dans les 24 heures suivant la circulation extracorporelle (CEC). Les critères d'évaluation secondaires comprenaient les événements indésirables postopératoires. Les associations ont été examinées par des modèles d'équation d'estimation généralisée hiérarchiques ajustés en fonction des caractéristiques démographiques et chirurgicales. RéSULTATS: La dose médiane de CCP [écart interquartile (ÉIQ)] était de 1000 [1000 à 2000] unités, tandis que la dose médiane [ÉIQ] de PC était de 4 [2-6] unités. Chaque unité de PC était indépendamment associée à une augmentation de la probabilité ajustée de transfusion d'érythrocytes (1,60; intervalle de confiance [IC] à 95 %, 1,36 à 1,87; P < 0,01) et de plaquettes (1,40; IC 95 %, 1,15 à 1,69; P < 0,01), alors que chaque 500 unités de CCP étaient indépendamment associées à une réduction de la probabilité ajustée de transfusion d'érythrocytes (0,67; IC 95 %, 0,50 à 0,90; P < 0,01) et de plaquettes (0,80; IC 95 %, 0,70 à 0,92; P < 0,01). Les taux d'événements indésirables étaient comparables. CONCLUSION: Chez les patients de chirurgie cardiaque présentant un saignement post-CEC, l'utilisation de CCP a été associée à un taux de transfusion plus faible d'érythrocytes et de plaquettes que lors de l'utilisation de PC. Des études cliniques randomisées prospectives comparant le PC au CCP dans ce type de contexte sont nécessaires.

Generation of hyperfunctional recombinant human factor IX variants expressed in human cell line SK-Hep-1.

OBJECTIVE: To develop recombinant factor IX (FIX) variants with augmented clotting activity. RESULTS: We generated three new variants, FIX-YKALW, FIX-ALL and FIX-LLW, expressed in SK-Hep-1 cells and characterized in vitro and in vivo. FIX-YKALW showed the highest antigen expression level among the variants (2.17 µg-mL), followed by FIX-LLW (1.5 µg-mL) and FIX-ALL (0.9 µg-mL). The expression level of FIX variants was two-five fold lower than FIX-wild-type (FIX-WT) (4.37 µg-mL). However, the biological activities of FIX variants were 15-31 times greater than FIX-WT in the chromogenic assay. Moreover, the new variants FIX-YKALW, FIX-LLW and FIX-ALL also presented higher specific activity than FIX-WT (17, 20 and 29-fold higher, respectively). FIX variants demonstrated a better clotting time than FIX-WT. In hemophilia B mice, we observed that FIX-YKALW promoted hemostatic protection. CONCLUSION: We have developed three improved FIX proteins with potential for use in protein replacement therapy for hemophilia B.

The European Association for Haemophilia and Allied Disorders (EAHAD) Coagulation Factor Variant Databases: Important resources for haemostasis clinicians and researchers.

INTRODUCTION: Advances in genomic sequencing have facilitated the sequencing of genes associated with disorders of haemostasis. The identification of variants within genes and access to curated data incorporating structural, functional, evolutionary as well as phenotypic data has become increasingly important in order to ascribe pathogenicity. AIM: The European Association for Haemophilia and Allied Disorders (EAHAD) Coagulation Factor Variant Database Project aims to provide a single port of entry to a web-accessible resource for variants in genes involved in clinical bleeding disorders. RESULTS: New databases have evolved from previously developed single gene variant coagulation database projects, incorporating new data, new analysis tools and a new common database architecture with new interfaces and filters. These new databases currently present information about the genotype, phenotype (laboratory and clinical) and structural and functional effects of variants described in the genes of factor (F) VII (F7), FVIII (F8), FIX (F9) and von Willebrand factor (VWF). CONCLUSION: The project has improved the quality and quantity of information available to the haemostasis research and clinical communities, thereby enabling accurate classification of disease severity in order to make assessments of likely pathogenicity.

Propensity score adjusted comparison of three-factor versus four-factor prothrombin complex concentrate for emergent warfarin reversal: a retrospective cohort study.

BACKGROUND: Prothrombin Complex Concentrates (PCC) are prescribed for emergent warfarin reversal (EWR). The comparative effectiveness and safety among PCC products are not fully understood. METHODS: Patients in an academic level one trauma center who received PCC3 or PCC4 for EWR were identified. Patient characteristics, PCC dose and time of dose, pre- and post-INR and time of measurement, fresh frozen plasma and vitamin K doses, and patient outcomes were collected. Patients whose pre-PCC International Normalized Ratio (INR) was > 6 h before PCC dose or the pre-post PCC INR was > 12 h were excluded. The primary outcome was achieving an INR ≤ 1.5 post PCC. Secondary outcomes were the change in INR over time, post PCC INR, thromboembolic events (TE), and death during hospital stay. Logistic regression modelled the primary outcome with and without a propensity score adjustment accounting for age, sex, actual body weight, dose, initial INR value, and time between INR measurements. Data are reported as median (IQR) or n (%) with p < 0.05 considered significant. RESULTS: Eighty patients were included (PCC3 = 57, PCC4 = 23). More PCC4 patients achieved goal INR (87.0% vs. 31.6%, odds ratio (OR) = 14.4, 95% CI: 3.80-54.93, p < 0.001). This result remained true after adjusting for possible confounders (AOR = 10.7, 95% CI: 2.17-51.24, p < 0.001). The post-PCC INR was lower in the PCC4 group (1.3 (1.3-1.5) vs. 1.7 (1.5-2.0)). The INR change was greater for PCC4 (2.3 (1.3-3.3) vs. 1.1 (0.6-2.0), p = 0.003). Death during hospital stay (p = 0.52) and TE (p = 1.00) were not significantly different. CONCLUSIONS: PCC4 was associated with a higher achievement of goal INR than PCC3. This relationship was observed in the unadjusted and propensity score adjusted results.

Factor VIII prophylaxis effects outweigh other hemostasis contributors in predicting severe haemophilia A joint outcomes.

INTRODUCTION: The Joint Outcome Study (JOS) demonstrated that previously untreated children with severe haemophilia A treated with prophylactic factor VIII (FVIII) concentrate had superior joint outcomes at age 6 years compared to those children treated episodically for bleeding. However, variation in joint outcome within each treatment arm was not well explained. AIM: In this study, we sought to better understand variation in joint outcomes at age 6 years in participants of the JOS. METHODS: We evaluated the influence of FVIII half-life, treatment adherence, constitutional coagulant and anticoagulant proteins, and global assays on joint outcomes (number of joint bleeds, total number of bleeds, total MRI score and joint physical exam score). Logistic regression was used to evaluate the association of variables with joint failure status on MRI, defined as presence of subchondral cyst, surface erosion or joint-space narrowing. Each parameter was also correlated with each joint outcome using Spearman correlations. RESULTS: Prophylaxis treatment arm and FVIII trough were each found to reduce risk of joint failure on univariate logistic regression analysis. When controlling for treatment arm, FVIII trough was no longer significant, likely because of the high level of covariation between these variables. We found no consistent correlation between any laboratory assay performed and any joint outcome parameter measured. CONCLUSION: In the JOS, the effect of prescribed prophylactic FVIII infusions on joint outcome overshadowed the contribution of treatment adherence, FVIII half-life, global assays of coagulation and constitutional coagulation proteins. (ClinicalTrials.gov number, NCT00207597).

Four-factor prothrombin complex concentrate dose response relationship with INR for warfarin reversal.

INTRODUCTION: For reversal of warfarin-induced coagulopathy, FDA labeling of four-factor prothrombin complex concentrate (4F-PCC) endorses a dosing strategy based on body weight and baseline INR. Recent literature suggests lower, fixed doses of 4F-PCC may be equally efficacious. The present evaluation aims to characterize the relationship between 4F-PCC dose and degree of reduction in INR. METHODS: This is a retrospective, single-center review of 4F-PCC administrations for warfarin reversal between May 2014 and August 2017. The primary endpoint evaluates the relationship between doses of 4F-PCC and INR measurement after reversal, represented as a linear regression. Exploratory endpoints characterize the relationships of both body weight and baseline INR, the components determining initial 4F-PCC dose, with INR after reversal. Additionally, for records presenting with an INR of 2-3.9, mean INR after reversal was characterized as a function of two 4F-PCC dose cohorts (< 30 and ≥30 IU fIX/kg). RESULTS: A significant linear relationship between 4F-PCC dose and INR after reversal (INR after 4F-PCC = 1.3651-0.00004(4F-PCC Dose), p = 0.0071, R2 = 0.0630) was observed. Body weight and baseline INR were not correlated with INR after reversal. The subgroup analysis of records with presenting INR of 2-3.9 demonstrated no difference in mean INR after reversal with 4F-PCC for those receiving <30 IU fIX/kg and those receiving ≥30 IU fIX/kg. CONCLUSION: This evaluation found no clinically relevant relationship with 4F-PCC doses and degree of INR reversal. Further prospective study is required to determine optimal dosing schemes of 4F-PCC for warfarin reversal.

Factor IX from prothrombin complex concentrate augments low dose tissue factor-triggered thrombin generation in vitro.

BACKGROUND: Prothrombin complex concentrate (PCC) is increasingly used to correct acquired coagulopathy in trauma and surgery. Dosing of PCC is guided by the prothrombin time, which only reflects the onset of thrombin generation, but does not account for variations in intrinsic pathway coagulation factors, including factor IX (FIX). We hypothesised that FIX contained in PCC could strongly influence thrombin generation patterns. METHODS: Pooled normal, FIX-deficient, and warfarinised plasma were used to analyse the effects of FIX contained in PCC. PCC was evaluated at final concentrations of 0.2 and 0.4 IU ml-1 in FIX-deficient and normal plasma, and at 0.6 IU ml-1 in warfarinised plasma with elevated FVIII (1.5 IU ml-1), 40% dilution with saline, or both. The effects on thrombin generation were assessed by measuring both procoagulant and inhibitory segments. RESULTS: FIX-deficient plasma had lower peak thrombin generation [30.6 (20.5-35.8) nM vs 130.2 (107-168) nM] and endogenous thrombin potential [472 (391-532) nM vs 1096 (958-1190) nM] than normal plasma. PCC addition resulted in significant increases of peak thrombin generation [81.8 (37.3-98.3) nM] and endogenous thrombin potential [808 (472-842) nM] in FIX-deficient plasma. The combination of FVIII and PCC resulted in greater increases relative to each agent alone, restoring normal thrombin generation. After 40% dilution, adding PCC, FVIII, or both, to FIX-deficient plasma increased peak thrombin generation, and prolonged the inhibitory phase of the endogenous thrombin potential. CONCLUSIONS: FIX derived from PCC strongly enhances tissue factor-triggered thrombin generation in the presence of elevated FVIII activity. Haemodilution further enhances procoagulant effects of FIX and FVIII by slowing down inhibition of procoagulant enzymes. Dosing of PCC per prothrombin time may underestimate PCC's procoagulant potential because it does not account for intrinsic tenase or antithrombin activity.

Prothrombotic factors do not increase the risk of recurrent ischemic events after cryptogenic stroke at young age: the FUTURE study.

BACKGROUND: The role of hypercoagulable states and preceding infections in the etiology of young stroke and their role in developing recurrent ischemic events remains unclear. Our aim is to determine the prevalence of these conditions in patients with cryptogenic stroke at young age and to assess the long-term risk of recurrent ischemic events in patients with and without a hypercoagulable state or a recent pre-stroke infection with Borrelia or Syphilis. PATIENTS AND METHODS: We prospectively included patients with a first-ever transient ischemic attack or ischemic stroke, aged 18-50, admitted to our hospital between 1995 and 2010. A retrospective analysis was conducted of prothrombotic factors and preceding infections. Outcome was recurrent ischemic events. RESULTS: Prevalence of prothrombotic factors did not significantly differ between patients with a cryptogenic stroke and with an identified cause (24/120 (20.0%) and 32/174 (18.4%) respectively). In patients with a cryptogenic stroke the long-term risk [mean follow-up of 8.9 years (SD 4.6)] of any recurrent ischemic event or recurrent cerebral ischemia did not significantly differ between patients with and without a hypercoagulable state or a recent infection. In patients with a cryptogenic stroke 15-years cumulative risk of any recurrent ischemic event was 24 and 23% in patients with and without any prothrombotic factor respectively. CONCLUSIONS: The prevalence of prothrombotic factors and preceding infections did not significantly differ between stroke patients with a cryptogenic versus an identified cause of stroke and neither is significantly associated with an increased risk of recurrent ischemic events after cryptogenic stroke.

Comparison of drug administration logistics between prothrombin complex concentrates and plasma in the emergency department.

BACKGROUND: Prothrombin complex concentrate (PCC) is used as an alternative to fresh frozen plasma (FFP) for emergency bleeding. The primary objective of this study was to compare the time from order to start of administration between 3-factor PCC (PCC3), 4-factor (PCC4), and FFP in the emergency department (ED). The secondary objective was to evaluate the effect of an ED pharmacist on time to administration of PCCs. METHODS: This was a single center three-arm retrospective cohort study. Adult patients in the ED with bleeding were included. The primary outcome measure was the time from order to administration, which was compared between PCC3, PCC4, and FFP. The time from order to administration was also compared when the ED pharmacist was involved versus not involved in the care of patients receiving PCC. RESULTS: There were 90 patients included in the study cohort (30 in each group). The median age was 69years (IQR 57-82years), and 57% (n=52) were male. The median time from order to administration was 36min (IQR 20-58min) for PCC3, 34min (IQR 18-48min) for PCC4, and 92min (IQR 63-133) for FFP (PCC3 versus PCC4, p=0.429; PCC3 versus FFP, p<0.001; PCC4 versus FFP, p<0.001). The median time from order to administration was significantly decreased when the ED pharmacist was involved (24min [IQR 15-35min] versus 42min [IQR 32-59min], p<0.001). CONCLUSIONS: Time from order to administration is faster with PCC than FFP. ED pharmacist involvement decreases the time from order to administration of PCC.

Coagulation F13A1 V34L, fibrinogen and homocysteine versus conventional risk factors in the pathogenesis of MI in young persons.

BACKGROUND: The pathogenesis of myocardial infarction (MI) involves environmental and genetic risk factors, with the latter putatively playing significant roles in younger patients. Genetic variability in coagulation factors comprises one such group. The coagulation factor 13 subunit A (F13A1) Val34Leu polymorphism (rs5985) has yielded variable findings in literature, with no prior South Asian data. METHODS: We studied the frequency of this polymorphism using the amplification-created restriction-enzyme site (ACRES) polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 101 MI patients aged below 40 years and 103 controls along with plasma fibrinogen and serum homocysteine levels. RESULTS: The distribution of Val/Val, Val/Leu and Leu/Leu genotypes was similar among cases (72.3%, 26.7% and 1.0%) and controls (78.6%, 19.4% and 1.9%, respectively). Val and Leu allele frequencies were 85.6% and 14.4% among patients and 88.3% and 11.7% among controls, respectively (p = .416). Mean plasma fibrinogen was higher in patients vis-à-vis controls (3.1 versus 3.7 g/l; p < .001) but homocysteine was elevated in both patients (52%) and controls (67%) (p = .225). Multivariate analysis revealed hypertension (p < .001, OR 6.16) and smoking (p < .001, OR 5.48) to impart strongest risk followed by positive family history, plasma fibrinogen levels and male gender. CONCLUSIONS: Despite its small sample size, this first South Asian study suggests neither protective nor deleterious effects of the F13A1 Val34Leu polymorphism on the risk of MI in young persons. The Leu allele frequency is intermediate to that reported from the West and the Far East. Traditional risk factors contribute greatly to risk even in younger MI patients in South Asia.