Haemostatic discs demonstrate physical efficacy against microbes commonly associated with central-line-associated bloodstream infections

BACKGROUND

Vascular access devices form an essential component in the management of acute and chronic medical conditions. Introduction and ongoing management of these devices are linked with bundles of care aimed at reducing associated risks including bleeding and infection.

AIM

To evaluate the antimicrobial potential of the potassium ferrate haemostatic disc on Gram-positive (Staphylococcus aureus) and Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria and on Candida albicans.

METHODS

The impact of the potassium ferrate disc was compared with the often-used chlorhexidine gluconate (CHG) impregnated disc to evaluate the potential efficacy of the potassium ferrate disc as an alternative to CHG in cases with an increased risk of active bleeding.

RESULTS

In the presence of anticoagulated blood, we observed an inhibitory effect of the haemostatic disc on microbial growth for microbial strains commonly associated with vascular access device related infections.

CONCLUSION

Our results indicate that the potassium ferrate disc may provide dual clinical benefits with both haemostatic and antimicrobial action observed during in-vitro testing.

Implementation of a Bleeding Management Algorithm in Liver Transplantation: A Pilot Study

Objectives

The aims of the study were to compare the consumption of blood products before and after the implementation of a bleeding management algorithm in patients undergoing liver transplantation and to determine the feasibility of a multicentre, randomized study.

Background

Liver transplantation remains the only curative therapy for patients with end-stage liver disease, but it carries a high risk of surgical bleeding.

Materials and Methods

Retrospective study of patients treated before (group 1) and after (group 2) implementation of a haemostatic algorithm guided by viscoelastic testing, including use of lyophilized coagulation factor concentrates (prothrombin complex and fibrinogen concentrates). Primary outcome was the number of units of blood products transfused in 24 h after surgery. Secondary outcomes included hospital stay, mortality, and cost.

Results

Data from 30 consecutive patients was analysed; 14 in group 1 and 16 in group 2. Baseline data were similar between groups. Median total blood product consumption 24 h after surgery was 33 U (IQR: 11-57) in group 1 and 1.5 (0-23.5) in group 2 (p = 0.028). Significantly fewer units of red blood cells, fresh frozen plasma, and cryoprecipitate were transfused in group 2 versus group 1. There was no significant difference in complications, hospital stay, or in-hospital mortality between groups. The cost of haemostatic therapy was non-significantly lower in group 2 versus group 1 (7,400 vs. 15,500 USD; p = 0.454).

Conclusion

The haemostatic management algorithm was associated with a significant reduction in blood product use during 24 h after liver transplantation. This study demonstrated the feasibility and provided a sample size calculation for a larger, randomized study.

Multiple myeloma and its treatment contribute to increased platelet reactivity

Multiple myeloma (MM) and its precursor states, smoldering myeloma (SM) and monoclonal gammopathy of undetermined significance (MGUS) are associated with increased incidence of thrombosis, however the cause of this is unknown. Lenalidomide treatment of MM substantially improves patient survival, although significantly increases thrombotic risk by an unknown mechanism. This pilot study aimed to establish the impact of MM and its treatment with Lenalidomide on platelet function. We analyzed platelet function in MGUS, SM and MM compared to healthy controls. We report an increase in platelet reactivity in MGUS, SM, and MM where increases in fibrinogen binding, P-selectin exposure, altered receptor expression, elevated levels of aggregation and enhanced sensitivity to agonist stimulation were observed. We also demonstrate an increase in patient platelet reactivity post Lenalidomide treatment compared to pre-treatment. We show Lenalidomide treatment of platelets ex vivo increased reactivity that was associated with formation of larger thrombi at arterial shear rates but not venous shear rates. This study demonstrates a clear increase in platelet reactivity and prothrombotic potential in patients with MGUS, SM and MM which is elevated further upon treatment with Lenalidomide. Our observations suggest that more detailed studies are warranted to determine mechanisms of thrombotic complications to enable the development of new preventative strategies that specifically target platelets.

A transparent synthetic peptide hydrogel as a haemostatic agent in athermal nerve sparing robot-assisted radical prostatectomy: an observational study

Background

PuraStat® is a new synthetic haemostatic agent constituting peptides that self-assemble into sheets when exposed to ionic charges. The objective of this submission is to assess the perioperative, functional and user-reported outcomes of PuraStat® as an athermal topical haemostatic agent for use on the neurovascular bundle (NVB) in robot-assisted radical prostatectomy (RARP), and to inform further research into this developing field.

Methods

Demographic and disease data for 29 consecutive patients undergoing RARP were recorded. PuraStat® was used as the primary haemostatic agent to the NVB, without thermal or suture haemostasis, unless necessary. Preoperative, 1-h postoperative and 24-h postoperative haemoglobin (Hb) were measured. Operative data including postoperative complications up to 30 days were noted. Urinary function, continence and erectile function (EF) were measured pre- and postoperatively with the International Prostate Symptom Score (IPSS), patient reporting of pad usage, and International Index of Erectile Function (IIEF)-5 respectively. A qualitative assessment of PuraStat® was made intraoperatively by the surgical assistant in the following categories: transparency, haemostatic efficacy, ready-to-use, handling, and overall satisfaction.

Results

Twenty-nine males aged between 49 and 75 years underwent a nerve-sparing RARP under a single surgeon for clinically significant prostate cancer with PuraStat® used as the primary haemostatic agent at the NVB. One patient required an additional haemostatic suture. The median prostate volume was 36 mL. Mean blood loss was 363 mL. The mean Hb at 1 and 24 h postoperative was 135.2 and 125.1 mg/dL. Median Hb change from 1-24 h postoperative was 11 mg/dL. No transfusions were required, and there were no postoperative complications. Urinary function and continence were preserved. EF in our series was lower than published data.

Conclusions

Our observational study suggests that PuraStat® is a safe haemostatic agent in RARP with similar perioperative bleeding outcomes, comparable long-term urinary outcomes and a high level of intraoperative user satisfaction. The effects on EF requires further investigation. PuraStat® appears to be a useful therapeutic tool for the urologist performing RARPs.

Removing direct oral factor Xa inhibitor interferences from routine and specialised coagulation assays using a raw activated charcoal product

BACKGROUND

Direct oral anticoagulants (DOACs) are increasingly prescribed for the prevention and treatment of thrombosis. However, DOACs are associated with extensive interference in coagulation assays. Herein, we evaluate raw activated charcoal (AC) as an adsorbent material, to minimise DOAC-associated interferences in routine and specialised coagulation parameters on CS-series analysers (Sysmex, Kobe, Japan).

METHODS

Commercial human-derived non-anticoagulated plasma materials, with or without increasing concentrations of anticoagulant, were assayed for routine and specialised coagulation parameters before and after treatment with AC.

RESULTS

Treatment of non-anticoagulated plasma with raw AC had minimal impact on routine and specialised coagulation parameters available on the CS-series; however, clinically relevant prolongations of certain activated partial thromboplastin time (APTT)-based assays were observed after treatment. Furthermore, in apixaban- and rivaroxaban-containing plasma material, AC efficiently adsorbed therapeutic and supratherapeutic DOAC concentrations; and, treatment with raw AC resolved DOAC-associated interferences on all affected routine and specialised coagulation parameters.

CONCLUSIONS

Overall, raw AC efficiently adsorbed apixaban and rivaroxaban from human-derived plasma, without significantly affecting the majority of underlying routine and specialised coagulation parameters available on CS-series analysers.

Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis

In traumatized patients, the primary cause of mortality is uncontrollable continuous bleeding and unexpected intraoperative bleeding which is likely to increase the risk of complications and surgical failure. High expansion sponges are effective clinical practice for the treatment of wound bleeding (irregular/deep/narrow) that are caused by capillaries, veins and even arterioles as they possess a high liquid absorption ratio so can absorb blood platelets easily in comparison with traditional haemostasis treatments, which involve compression, ligation, or electrical coagulation etc. When in contact with blood, haemostatic sponges can cause platelet adhesion, aggregation, and thrombosis, preventing blood from flowing out from wounds, triggering the release of coagulation factors, causing the blood to form a stable polymerized fibre protein, forming blood clots, and achieving the goal of wound bleeding control. Haemostatic sponges are found in a variety of shapes and sizes. The aim of this review is to facilitate an overview of recent research around haemostatic sponge materials, products, and technology. This paper reviews the synthesis, properties, and characteristics of haemostatic sponges, together with the haemostasis mechanisms of haemostatic sponges (composite materials), such as chitosan, cellulose, gelatin, starch, graphene oxide, hyaluronic acid, alginate, polyethylene glycol, silk fibroin, synthetic polymers silver nanoparticles, zinc oxide nanoparticles, mesoporous silica nanoparticles, and silica nanoparticles. Also, this paper reviews commercial sponges and their properties. In addition to this, we discuss various in-vitro/in-vivo approaches for the evaluation of the effect of sponges on haemostasis.

Free-flowing, self-crosslinking, carboxymethyl starch and carboxymethyl cellulose microgels, as smart hydrogel dressings for wound repair

Hydrogels are widely recognized and favoured as moist wound dressings due to their beneficial properties. However, their limited capacity to absorb fluids restricts their use in highly exuding wounds. Microgels are small sized hydrogels that have recently gained considerable attention in drug delivery applications due to their superior swelling behaviour and ease of application. In this study, we introduce dehydrated microgel particles (μGeld) that rapidly swell and interconnect, forming an integrated hydrogel when exposed to fluid. These free-flowing microgel particles, derived from the interaction of carboxymethylated forms of starch and cellulose, have been designed to significantly absorb fluid and release silver nanoparticles in order to effectively control infection. Studies using simulated wound models validated the microgels ability to efficiently regulate the wound exudate and create a moist environment. While the biocompatibility and hemocompatibility studies confirmed the safety of the μGel particles, its haemostatic property was established using relevant models. Furthermore, the promising results from a full-thickness wounds in rats have highlighted the enhanced healing potential of the microgel particles. These findings suggest that the dehydrated microgels can evolve as a new class of smart wound dressings.

Changes in haemostasis and inflammatory markers after mRNA BNT162b2 and vector Ad26.CoV2.S SARS-CoV-2 vaccination

INTRODUCTION

Reported thromboembolic events after SARS-CoV-2 vaccinations are still raising concerns, predominantly in non-scientific population. The aim of our study was to investigate the differences between haemostasis and inflammatory markers in the subjects vaccinated with mRNA BNT162b2 and vector Ad26.CoV2.S vaccine.

MATERIALS AND METHODS

The study included 87 subjects vaccinated with mRNA BNT162b2 and 84 with Ad26.CoV2.S vaccine. All the laboratory parameters (TAT, F 1 + 2, IL-6, CRP, big endothelin-1, platelets, fibrinogen, D-dimers, VWF activity) were investigated for the mRNA vaccine at five (before the first dose, 7 and 14 days after the first and second vaccine dose), and three time points (before the first dose, 7 and 14 days after) for the vector vaccine, respectively. All the markers were measured by well-established laboratory methods.

RESULTS

Our results have shown statistically higher CRP levels in the vector group 7 days after vaccination (P = 0.014). Furthermore, study has revealed statistically significant rise in D-dimers (P = 0.004) between tested time points in both vaccine groups but without clinical repercussions.

CONCLUSION

Although statistically significant changes in haemostasis markers have been obtained, they remained clinically irrelevant. Thus, our study implicates that there is no plausible scientific evidence of a significant disruption in the coagulation and inflammatory processes after vaccination with BNT162b2 mRNA and Ad26.CoV2.S vector SARS-CoV-2 vaccines.

A prospective randomised controlled trial evaluating prophylactic Floseal, a gelatin and thrombin-based haemostatic matrix, in postoperative drain output and blood transfusion in transforaminal lumbar interbody fusion surgery

PURPOSE

To evaluate the prophylactic use of Floseal in reducing postoperative blood loss in patients undergoing Transforaminal Lumbar Interbody Fusion (TLIF). TLIF is a lumbar spine decompression and fusion procedure with potential for postoperative blood loss. Prophylactic application of Floseal, a gelatin and thrombin-based haemostatic matrix to the surgical wound before closure was shown to be effective in reducing postoperative drain output in anterior cervical discectomy and fusion. This study postulated that prophylactic use of Floseal before wound closure would reduce postoperative blood loss in patients who underwent TLIF.

METHODS

Randomised controlled trial comparing prophylactic use of Floseal and control in patients undergoing single level or two-level TLIF. Primary outcomes included postoperative drain output within 24 h and postoperative transfusion rate. Secondary outcomes included days of drain placement, length of stay and haemoglobin level.

RESULTS

A total of 50 patients was recruited. Twenty six patients were allocated to the Floseal group and 24 were allocated to the control group. There were no baseline characteristic differences between the groups. There were no statistically significant differences in primary outcomes which included postoperative drain output within 24 h and postoperative transfusion rate between patients who received prophylactic Floseal and control. There were no statistically significant differences in secondary outcomes which included haemoglobin level, days of drain placement and length of stay between the two groups.

CONCLUSION

Prophylactic use of Floseal was not shown to reduce postoperative bleeding in single level or two-level TLIF.

Trace Metals and The Hemostatic System

In this narrative review we report the main relationships between trace metals and the hemostatic system since this aspect has seldom attracted the attention of the scientific community. A basic aspect to be considered is the importance of maintaining the fine control of all trace metals' levels since they have an important impact on the pathophysiology of the hemostatic system. It is worth noting that poor diet habits are responsible for most trace metal deficiencies, while pollution is responsible for dangerous exposure to them with a consequent negative impact on the general population. This appears of paramount importance in planning the implementation of food and nutrient support to ameliorate the hidden hunger and the quality of life of people especially in developing countries and limiting poisons both in the air and food. As it often happens, when damage to certain mechanisms takes a very long time to appear, no attention is paid to the importance of a systematic prevention to avoid late negative outcomes.

Bipolar haemostatic forceps versus standard therapy by haemoclip + / - epinephrine injection as initial endoscopic treatment in active non-variceal upper GI bleeding: study protocol for a prospective, randomized multicentre trial (BeBop-Trial)

BACKGROUND

Patients with active nonvariceal upper gastrointestinal bleeding (NVUGIB) usually require urgent endoscopic treatment. Standard therapy (ST) using haemoclip + / - epinephrine injection is not always successful. Bipolar haemostatic forceps (HemoStat/Pentax®) are an approved medical device for the treatment of gastrointestinal bleeding. However, their use as a primary endoscopic treatment for active NVUGIB has not yet been proven in a randomized prospective study.

METHODS

This is a prospective, randomized, multicentre superiority trial (n ≥ 5). Patients with active NVUGIB will be randomized (1:1) to ST and to experimental therapy (ET) by application of bipolar haemostatic forceps. In the case of failed initial treatment within 15 min, crossover treatment will be attempted first. Rescue treatment (e.g. via over-the-scope-clip) will then be allowed after 30 min. All patients will also receive standard therapy with proton pump inhibitors. Forty-five patients per treatment arm are required to demonstrate an absolute difference of 25.4% with a power of 80% and a significance level of 0.05.

DISCUSSION

The hypothesis of the study is that bipolar haemostatic forceps are superior to ST in terms of successful primary haemostasis and the absence of recurrent bleeding within 30 days (combined endpoint). The 1:1 randomization is also ethically justifiable for this study, as both procedures are approved for the intervention in question. To further increase the safety of the patients in the study, crossover treatment and rescue treatment are planned. The prospective design seems feasible in a reasonable time frame (recruitment period of 12 months), as nonvariceal upper gastrointestinal bleeding is common. Anticoagulants and/or antiplatelet drugs could be an important confounding factor in the statistical analysis that needs to be taken into account and calculated if necessary. In conclusion, this randomized, prospective, multicentre study could make an important contribution to answering the question of whether bipolar haemostatic forceps could be the first-line therapy in the endoscopic treatment of stage Forrest I a + b NVUGIB.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05353062. Registered on April 30 2022.

Effects of Rheum rhaponticum and Rheum rhabarbarum extracts on haemostatic activity of blood plasma components and endothelial cells in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional medicine recommends the use of Rheum rhaponticum L. and R. rhabarbarum L. to treat over thirty complaints, including disorders related to the cardiovascular system such as heartache, pains in the pericardium, epistaxis and other types of haemorrhage, blood purification as well as disorders of venous circulation.

AIM OF THE STUDY

This work was dedicated to examining for the first time the effects of extracts from petioles and roots of R. rhaponticum and R. rhabarbarum, as well as two stilbene compounds (rhapontigenin and rhaponticin) on the haemostatic activity of endothelial cells and functionality of blood plasma components of the haemostatic system.

MATERIALS AND METHODS

The study was based on three main experimental modules, including the activity of proteins of the human blood plasma coagulation cascade and the fibrinolytic system as well as analyses of the haemostatic activity of human vascular endothelial cells. Additionally, interactions of the main components of the rhubarb extracts with crucial serine proteases of the coagulation cascade and fibrinolysis (i.e. thrombin, the coagulation factor Xa and plasmin) were analyzed in silico.

RESULTS

The examined extracts displayed anticoagulant properties and significantly reduced the tissue factor-induced clotting of human blood plasma (by about 40%). Inhibitory effects of the tested extracts on thrombin and the coagulation factor Xa (FXa) were found as well. For the extracts, the IC₅₀ was ranging from 20.26 to 48.11 μg/ml. Modulatory effects on the haemostatic response of endothelial cells, including the release of von Willebrand factor, tissue-type plasminogen activator and the plasminogen activator inhibitor-1, have been also found.

CONCLUSIONS

Our results indicated for the first time that the examined Rheum extracts influenced the haemostatic properties of blood plasma proteins and endothelial cells, with the prevalence of the anticoagulant action. The anticoagulant effect of the investigated extracts may be partly attributed to the inhibition of the FXa and thrombin activities, the key serine proteases of the blood coagulation cascade.

Amplification of protease-activated receptors signaling in sporadic cerebral cavernous malformation endothelial cells

In the central nervous system, thrombin-mediated activation of protease-activated receptors (PARs) results in neuroinflammation and increased vascular permeability. These events have been linked to cancer and neurodegeneration. Endothelial cells (ECs) isolated from sporadic cerebral cavernous malformation (CCM) specimens showed dysregulation of genes involved in "thrombin-mediated PAR-1 activation" signaling. CCM is a vascular disease involving brain capillaries. In CCM, ECs show defective cell junctions. Oxidative stress and neuroinflammation play a key role in disease onset and progression. In order to confirm the possible role of thrombin pathway in sporadic CCM pathogenesis, we evaluated PARs expression in CCM-ECs. We found that sporadic CCM-ECs overexpress PAR1, PAR3 and PAR4, together with other coagulation factor encoding genes. Moreover, we investigated about expression of the three familial CCM genes (KRIT1, CCM2 and PDCD10) in human cerebral microvascular ECs, following thrombin exposure, as well as protein level. Thrombin exposure affects EC viability and results in dysregulation of CCM gene expression and, then, in decreased protein level. Our results confirm amplification of PAR pathway in CCM suggesting, for the first time, the possible role of PAR1-mediated thrombin signaling in sporadic CCM. Thrombin-mediated PARs over activation results in increased blood-brain barrier permeability due to loss of cell junction integrity and, in this context, also the three familial CCM genes may be involved.

The new in anticoagulation: factor XI inhibitors

Haemostasis and thrombosis are closely linked, so that any anticoagulant strategy available today that reduces the thrombotic risk inevitably increases the bleeding risk. However, epidemiological and experimental evidence suggests that inhibiting the contact pathway-the first phase of the intrinsic coagulation pathway-and especially factor XI (FXI) achieves the objective of preventing thrombosis with minimal interference on the haemostatic process. Several pharmacological strategies that act by inhibiting FXI are being studied in clinical trials. Specifically, Phase 2 clinical trials in patients undergoing major orthopaedic surgery, end-stage renal disease, atrial fibrillation (AF), and acute coronary syndrome have shown promising results, allowing clinical research to advance into Phase 3 clinical trials. FXI inhibitors will not necessarily replace currently available direct oral anticoagulants: this would appear too ambitious as of today. However, it is possible to hypothesize that FXI inhibitors are a useful addition to our therapeutic armamentarium in contexts where current anticoagulants have failed or have not been adequately tested, as well as in categories of patients who are at a high risk of bleeding even with current direct oral anticoagulants.

Pulsed thulium laser blood vessel haemostasis as an alternative to bipolar forceps during neurosurgical tumour resection

Due to wavelength-specific water absorption, infrared lasers like the thulium laser emitting at 1940 nm wavelength proved to be suitable for coagulation in neurosurgery. Commonly bipolar forceps used for intraoperative haemostasis can cause mechanical and thermal tissue damage, whilst thulium laser can provide a tissue-gentle haemostasis through non-contact coagulation. The aim of this work is a less-damaging blood vessel coagulation by pulsed thulium laser radiation in comparison to standard bipolar forceps haemostasis. Ex vivo porcine blood vessels in brain tissue (0.34 ± 0.20 mm diameter) were irradiated in non-contact with a thulium laser in pulsed mode (1940 nm wavelength, 15 W power, 100-500 ms pulse duration), with a CO2 gas flow provided simultaneously at the distal fibre tip (5 L/min). In comparison, a bipolar forceps was used at various power levels (20-60 W). Tissue coagulation and ablation were evaluated by white light images and vessel occlusion was visualised by optical coherence tomography (OCT) B-scans at a wavelength of 1060 nm. Coagulation efficiency was calculated by means of the quotient of the difference between the coagulation and ablation radius to the coagulation radius. Pulsed laser application achieved blood vessel occlusion rate of 92% at low pulse duration of 200 ms with no occurrence of ablation (coagulation efficiency 100%). Bipolar forceps showed an occlusion rate of 100%, however resulted in tissue ablation. Tissue ablation depth with laser application is limited to 40 μm and by a factor of 10 less traumatising than with bipolar forceps. Pulsed thulium laser radiation achieved blood vessel haemostasis up to 0.3 mm in diameter without tissue ablation and has proven to be a tissue-gentle method compared to bipolar forceps.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Monitoring heparin therapy: stability of two different anti-Xa assays using blood samples collected in citrate-containing and CTAD tubes

BACKGROUND

Anti-factor Xa assays and activated partial thromboplastin time (aPTT) are mainly employed to monitor patients treated with heparins. According to the Clinical and Laboratory Standards Institute and the French Working Group on Haemostasis and Thrombosis, anti-factor Xa activity and aPTT should be tested within 2 h of blood sampling for unfractionated heparin (UFH) monitoring. However, discrepancies exist depending on the used reagents and collecting tubes. The study aim was to determine the stability of aPTT and anti-factor Xa measurements using blood samples collected in citrate-containing or citrate-theophylline-adenosine-dipyridamole (CTAD) tubes and stored for up to 6 h.

METHODS

Patients receiving UFH or low molecular weight heparin (LMWH) were enrolled; aPTT and anti-factor Xa activity were tested using two different analyser/reagent pairs (Stago and reagent without dextran sulfate; Siemens and reagent with dextran sulfate) after 1, 4 and 6 h of sample storage as whole blood or as plasma.

RESULTS

For UFH monitoring, comparable anti-factor Xa activity and aPTT results were obtained with both analyser/reagent pairs when samples were stored as whole blood before plasma isolation. With samples stored as plasma, anti-factor Xa activity and aPTT were not affected up to 6 h after sampling when using the Stago/no-dextran sulfate reagent pair. With the Siemens/dextran sulfate-containing reagent, aPTT was significantly altered after 4 h of storage. For LMWH monitoring, anti-factor Xa activity remained stable (whole blood and plasma) for at least 6 h. Results were comparable with citrate-containing and CTAD tubes.

CONCLUSIONS

Anti-factor Xa activity in samples stored as whole blood or plasma was stable for up to 6 h, regardless of the reagent (with/without dextran sulfate)/collection tube. Conversely, aPTT was more variable because other plasma parameters can influence its measure and complicate the interpretation of its variations after 4 h.

Acute high-intensity interval exercise is less pro-oxidative/thrombotic compared to isovolumic moderate-intensity steady-state exercise

While high-intensity interval training (HIIT) has emerged as a more time-efficient alternative to moderate-intensity steady-state exercise (MISS), the impact on systemic free radical formation and link to activated coagulation remains unknown. We recruited sixteen healthy males aged 21 ± 3 y who performed incremental cycle ergometry to determine peak oxygen uptake ([Formula: see text] _PEAK). Participants were randomly assigned single blind to two separate groups (MISS: n = 8; HIIT: n = 8) matched for [Formula: see text] _PEAK. HIIT participants completed five exercise cycles, each consisting of 3 min at 80%[Formula: see text] _PEAK alternating with 3 min at 40% [Formula: see text] _PEAK, whereas MISS participants performed an isovolumic bout of 30 min at 60% [Formula: see text] _PEAK. Cephalic venous blood was assayed for ascorbate free radical (A^•-, electron paramagnetic resonance spectroscopy) and clot fractal dimension (d_f, rheometry) at rest every hour over a 6-h period to determine critical difference (CD) and before/after submaximal/peak exercise. Submaximal MISS increased A^{• -} and d_f to a greater extent compared to HIIT (P = 0.039 to 0.057) although elevations generally fell within CD boundaries (54.2% and 5.5% respectively). No further elevations were observed during peak exercise (P = 0.508 to 0.827) and no relationships were observed between A^•- and d_f (r = 0.435 to - 0.121, P = 0.092 to 0.655). Collectively, these findings suggest that HIIT is less pro-oxidative/thrombotic compared to more traditional MISS, advocating its prescription in patients given the potential for superior vascular adaptive benefit.

Inflammation-mediated changes in haemostatic variables of pulmonary tuberculosis patients during treatment

Tuberculosis (TB) disease is usually marked by inflammation which is closely linked to haemostasis both in health and disease. Close monitoring of haemostatic response to inflammatory changes during treatment is important to improve TB management. Here we studied associations between haemostatic markers and inflammatory cytokines in 60 TB-infected individuals, aged 18-65 years who received anti-TB therapy. They were recruited before commencement of therapy and followed up till completion of therapy after 6-months. The TNF-α, IL-6, IL-2 (pro-inflammatory cytokines) and P-selectin, GP IIb/IIIa, thrombopoietin (haemostatic variables) were significantly increased at 2 month into therapy compared to pre-treatment values and decreased at 6 month into therapy. Also at 6 month into therapy in comparison to 2-month into therapy, there were significant increase in IL-10 and TGF-β (anti-inflammatory cytokines) as well as a significant decline in PF-4. There were significant positive correlations between GP IIb/IIIa and TNF-α, IL-6 and PSEL, IL-6 and TPO, PF4 and TGF-β. Conclusively, the changes in the TNF-α, IL-6, IL-2 aligned with changes in the levels of P-selectin, GP IIb/IIIa, and TPO in the course of TB therapy. This may suggest that the levels of inflammatory cytokines are linked to the levels of these haemostatic variables in TB individuals.

Haemostasis patterns in patients with acute-on-chronic liver failure and acute decompensation of cirrhosis including thromboelastometric tests with and without the addition of Protac: a pilot study

BACKGROUND

Thromboelastometry is considered the best method to assesses hemostasis in liver disease. Diagnostic performance could be improved by adding protein C activators such as thrombomodulin or Protac®. We assessed changes in ROTEM parameters after the addition of Protac® in patients with acute-on-chronic liver failure (ACLF), acute decompensation (AD), and healthy individuals (HI) to define different hemostasis patterns, considering standard and velocity ROTEM parameters, and assess whether Protac® can improve the definition of the pattern.

METHODS

Pre-test, we investigated whether diluted EXTEM reagent improved the effect of Protac® on the clotting time (CT)-ratio with and without Protac®. Ten ACLF and 20 AD patients and 21 HI were included in the main study.

RESULTS

Standard EXTEM was used in the main study. INTEM CFT, INTEM A5 (inverse), and INTEM TPI (inverse) were the parameters that best differentiated liver disease from HI (ROC AUC, 0.921, 0.906, and 0.928, respectively; all P-values < 0.001). Combining INTEM CFT with EXTEM LI60-ratio only slightly improved the diagnostic performance (ROC AUC, 0.948; P < 0.001). EXTEM LI60 and INTEM maxV-t were the parameters that best differentiated between ACLF and AD patients (ROC AUC, 0.743, P = 0.033; and 0.723, P = 0.050; respectively). Combining EXTEM LI60 + INTEM maxV-t moderately improved the diagnostic performance (ROC AUC, 0.81, P < 0.001).

CONCLUSIONS

ROTEM velocity, fibrinolysis parameters and the indices calculated improve the diagnosis in combination with standard parameters (e.g., CFT and A5). Ratios calculated with and without Protac® (e.g., EXTEM LI60-ratio) only slightly increased the diagnostic performance in discriminating hemostasis patterns.

Injectable adhesive self-healing biocompatible hydrogel for haemostasis, wound healing, and postoperative tissue adhesion prevention in nephron-sparing surgery

Nephron-sparing surgery is a well-established treatment in patients with T1a renal cell carcinoma; however, the complex suturing process prolongs warm ischaemia time, affects the preservation of normal renal parenchymal function, and causes avoidable postoperative tissue adhesion complications, including chronic abdominal pain, intestinal obstruction, and female infertility. Hence, the design of multifunctional biomaterials with haemostasis, postoperative wound management, and postoperative tissue adhesion prevention properties for nephron-sparing surgeries is urgently needed. In this study, a series of injectable adhesive multifunctional biocompatible hydrogels were designed based on the free-radical polymerisation of monomers acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG), and the ionic coordination between Ca²⁺ and the abundant carboxyl groups in AA and NAG. AA/NAG/Ca (AA, NAG, and Ca refer to acryloyl-6-aminocaproic acid, N-acryloyl 2-glycine and calcium chloride, respectively) hydrogel exhibited good mechanical properties, swelling and adhesion properties, flexibility, in vitro blood-clotting ability, and cytocompatibility. In vivo experiments on liver injury models and rat/rabbit nephron-sparing surgery models elucidated that the AA/NAG/Ca hydrogel had haemostasis performance and wound healing properties that led to short bleeding time, reduced bleeding volume, and well-organised nephron structures. An abdomen-caecum adhesion model indicated that the AA/NAG/Ca hydrogel showed excellent anti-adhesion properties. In summary, this multifunctional hydrogel exhibited potential for improving haemostasis and wound management in nephron-sparing surgeries, showing potential for clinical application. STATEMENT OF SIGNIFICANCE: Extended warm ischemia time during nephron sparing surgery negatively affected postoperative renal function due to the need for hemostasis at the wound with abundant blood supply, and postoperative wound healing and additional adhesions caused by the surgical procedure deserve attention. Based on the efficient and stable adhesion properties of hydrogels and the ability to promote wound healing. Herein, a series of adhesive self-healing biocompatible hydrogels were prepared based on free-radical polymerization of acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG) and the ionic coordination between Ca²⁺ with the abundant carboxyl groups in AA and NAG. AA/NAG/Ca hydrogel showed hemostasis property in nephron sparing surgery model, promote kidney wound healing, and could perform anti-postoperative adhesion efficacy in an abdomen-caecum adhesion model.

Life-threatening chlorpromazine-induced acquired haemophilia A in a patient with a cavernous malformation involving the medulla oblongata

INTRODUCTION

Chlorpromazine is a commonly used drug in several medical conditions associated with a wide range of side effects. Few cases of hemostatic disorder have been reported in the literature.

CASE REPORT

A 39-year-old man had previously been diagnosed with a cavernous malformation of the medulla oblongata. Chlorpromazine was started to treat persistent hiccups. Twenty days later, the patient presented hepatitis and a pruritic rash. Haemostasis tests revealed a prolonged partial thromboplastin time associated with isolated decrease of factor VIII level and anti-factor VIII antibodies. Magnetic resonance imaging revealed recent asymptomatic bleeding. Introduction of eptacog alfa and prednisone allowed clinical and biological improvement as well as a prolonged remission after 12 months of follow-up.

Survival outcomes and predictors of mortality, re-bleeding and complications for acute severe variceal bleeding requiring balloon tamponade

BACKGROUND

Acute severe variceal bleeding (AVB) refractory to medical and endoscopic therapy is infrequent but associated with high mortality. Historical cohort studies from 1970-1980s no longer represent the current population as balloon tamponade is no longer first-line therapy for variceal bleeding; treatments including vasoactive therapies, intravenous antibiotics, endoscopic variceal band ligation are routinely used, and there is improved access to definitive treatments including transjugular intrahepatic portosystemic shunts. However, only a few studies from the current era exist to describe the practice of balloon tamponade, its outcomes, and predictors with a requirement for further updated information.

AIM

To describe current management of AVB requiring balloon tamponade and identify the outcomes and predictors of mortality, re-bleeding and complications.

METHODS

A retrospective multi-centre cohort study of 80 adult patients across two large tertiary health networks from 2008 to 2019 in Australia who underwent balloon tamponade using a Sengstaken-Blakemore tube (SBT) were included for analysis. Patients were identified using coding for balloon tamponade. The primary outcome of this study was all-cause mortality at 6 wk after the index AVB. Secondary outcomes included re-bleeding during hospitalisation and complications of balloon tamponade. Predictors of these outcomes were determined using univariate and multivariate binomial regression.

RESULTS

The all-cause mortality rates during admission and at 6-, 26- and 52 wk were 48.8%, 51.2% and 53.8%, respectively. Primary haemostasis was achieved in 91.3% and re-bleeding during hospitalisation occurred in 34.2%. Independent predictors of 6 wk mortality on multivariate analysis included the Model for Endstage Liver disease (MELD) score (OR 1.21, 95%CI 1.06-1.41, P = 0.006), advanced hepatocellular carcinoma (OR 11.51, 95%CI 1.61-82.20, P = 0.015) and re-bleeding (OR 13.06, 95%CI 3.06-55.71, P < 0.001). There were no relevant predictors of re-bleeding but a large proportion in which this occurred did not survive 6 wk (76.0% vs 24%). Although mucosal trauma was the most common documented complication after SBT insertion (89.5%), serious complications from SBT insertion were uncommon (6.3%) and included 1 patient who died from oesophageal perforation.

CONCLUSION

In refractory AVB, balloon tamponade salvage therapy is associated with high rates of primary haemostasis with low rates of serious complications. Re-bleeding and mortality however, remain high.

The association of coagulation and atrial fibrillation: a systematic review and meta-analysis

AIMS

While atrial fibrillation (AF) is suggested to induce a prothrombotic state, increasing thrombotic risk, it is also hypothesized that coagulation underlies AF onset. However, conclusive evidence is lacking. With this systematic review and meta-analysis, we aimed to summarize and combine the evidence on the associations between coagulation factors with AF in both longitudinal and cross-sectional studies.

METHODS AND RESULTS

We systematically searched for longitudinal cohort and cross-sectional studies investigating AF and thrombosis. For longitudinal studies, pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. For cross-sectional studies, we determined pooled standardized mean differences (SMDs) and 95% CIs. A total of 17 longitudinal and 44 cross-sectional studies were included. In longitudinal studies, we found significant associations between fibrinogen (HR 1.05, 95% CI 1.00-1.10), plasminogen activator inhibitor 1 (PAI-1) (HR 1.06, 95% CI 1.00-1.12), and D-dimer (HR 1.10, 95% CI 1.02-1.19) and AF incidence. In cross-sectional studies, we found significantly increased levels of fibrinogen (SMD 0.47, 95% CI 0.20-0,74), von Willebrand factor (SMD 0.96, 95% CI 0.28-1.66), P-selectin (SMD 0.31, 95% CI 0.08-0.54), ß-thromboglobulin (SMD 0.82, 95% CI 0.61-1.04), Platelet Factor 4 (SMD 0.42, 95% CI 0.12-0.7), PAI-1 (1.73, 95% CI 0.26-3.19), and D-dimer (SMD 1.74, 95% CI 0.36-3.11) in AF patients, as opposed to controls.

CONCLUSION

These findings suggest that higher levels of coagulation factors are associated with prevalent and incident AF. These associations are most pronounced with prevalent AF in cross-sectional studies. Limited evidence from longitudinal studies suggests a prothrombotic state underlying AF development.

Haemostatic profile of children with nephrotic syndrome attending University of Nigeria Teaching Hospital Ituku-Ozalla, Nigeria

Background

Haemostatic derangements are thought to be due to an imbalance between hepatic synthesis of pro-coagulants and urinary losses of anticoagulants.

Objectives

This study evaluated the coagulation profile of Nigerian children with nephrotic syndrome and examined the relationship between coagulation variables, disease state and steroid responsiveness.

Methods

A cross- sectional hospital based study on evaluation of coagulation profile of children with nephrotic syndrome compared with their age- and gender- matched controls.

Results

The median fibrinogen level in subjects and controls was the same (2.9 g/L). Sixteen of 46 (35%) children with nephrotic syndrome had hyperfibrinogenaemia. The median fibrinogen level of children in remission was 2.3 g/L and differed significantly when compared with those of children in relapse (p = 0.001). The median APTT of children with nephrotic syndrome was 45.0 s and differed significantly compared with those of controls (42.0 s) (p value = 0.02). The median prothrombin time in children with and without nephrotic syndrome were 12.0 and 13.0 s respectively, (p = 0.004). About 90% of children with nephrotic syndrome had INR within reference range. Thrombocytosis was found in 15% of children with nephrotic syndrome. The median platelet count in children with new disease was 432 × 10³cells/mm³ and differed significantly when compared with those of controls (p = 0.01).

INR was significantly shorter in children with steroid resistant nephrotic syndrome (SRNS) (median 0.8 s; IQR 0.8 -0.9 s) compared with controls (median 1.0 s; IQR 1.0 -1.1 s) (p = 0.01). Steroid sensitivity was the strongest predictor of remission in children with nephrotic syndrome; steroid sensitive patients were 30 times more likely to be in remission than in relapse (OR 30.03; CI 2.01 – 448.04).

Conclusion

This study shows that the haemostatic derangements in childhood nephrotic involve mostly fibrinogen, APTT, PT, INR and platelet counts. Antithrombin levels are largely unaffected. Variations in fibrinogen, APTT, PT and INR values may be due to the heterogeneous nature of the disease.

Poly (vinyl alcohol) copolymerized with xanthan gum/hypromellose/sodium carboxymethyl cellulose dermal dressings functionalized with biogenic nanostructured materials for antibacterial and wound healing application

Effective treatment of infected wounds requires a comprehensive wound dressing with a combination of antibacterial, antioxidative, and anti-inflammatory effects. Biodegradable wound dressings incorporating nanostructured material were developed using polyvinyl alcohol with xanthan gum, hypromellose, or sodium carboxymethyl cellulose and extensively evaluated for antibacterial and wound healing efficacy. Synthesized silver nanoparticles and wound dressings displayed λ_max at 420 nm with zeta potential ≈ - 35 mV. Significant growth inhibition with >99 % reduction in CFU/ml (p < 0.05) against important wound pathogens including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were observed. Within 1 h of treatment, hypromellose nanocomposite demonstrated excellent bactericidal effects with a 99.9 % of reduction in growth. In addition, wound dressings demonstrated inhibitory activities against free radical scavengers. Wound dressings demonstrated a significant reduction in the inflammatory response in RAW 264.7 macrophages (p < 0.001). Ex-vivo diffusion demonstrated zero-order release and steady-state flux between 0.1571-0.2295 μg/ml/cm²h with 0.124-0.144 permeability coefficient after 10 h. Usage in animals further confirmed that the hypromellose nanocomposite accelerated the wound healing process with biocompatibility. The results suggested that hybrid biodegradable dressings can be effectively applied to treat infected wounds and attenuate inflammatory responses.

Topical administration of tranexamic acid in elderly patients undergoing short femoral nailing for intertrochanteric fracture: A randomised controlled trial

INTRODUCTION

Topical application of tranexamic acid (TXA) has been proposed as an alternative to intravenous administration to reduce perioperative bleeding in orthopaedic surgery. The purpose of this randomised controlled trial was to evaluate the efficacy and safety of 1 g topically applied TXA in patients undergoing fixation of intertrochanteric hip fractures by short femoral nailing.

METHODS

A total of 121 patients were enrolled between May 2018 and January 2020. Patients were randomly allocated (1:1) to receive either 10 mL (1 g) of TXA or 10 mL of normal saline (NS) injected through the subfascial drain following wound closure. Total blood loss, total drain output and blood transfusion requirements up to postoperative day 3 were recorded. Rates of thromboembolic complications and mortality up to 90 days postoperatively were also compared.

RESULTS

There was no statistically significant difference in total blood loss, total drain output or proportion of patients requiring transfusions. Median total blood loss was 1.088 L (IQR: 0.760-1.795) in the TXA group and 1.078 L (IQR: 0.797-1.722) in the NS group (P = .703). Median total drain output was 60 mL (IQR: 40-140) in the TXA group and 70 mL (IQR: 30-168) in the NS group (P = .696). Blood transfusions were administered in 29 patients (47.5%) in the TXA group and 27 patients (45.0%) in the NS group (P = .782). There was also no difference in frequency of thrombotic complications or mortality within 90 days. There were five thrombotic events in the TXA group and four in the NS group (P = .751). The 90-day mortality rate was 6.6% (4 patients) in the TXA group and 3.3% (2 patients) in the NS group (P = .680).

CONCLUSION

A 1 g dose of topically administered TXA did not produce any difference in blood loss, transfusion requirements, thromboembolic complications, or 90-day mortality. Future trials may consider the effect of larger doses in patients undergoing hip fracture fixation surgery.

Current management and clinical outcomes for patients with haemorrhagic shock due to pelvic fracture in Korean regional trauma centres: A multi-institutional trial

INTRODUCTION

The purpose of this study was to evaluate the current management and clinical outcomes in patients with hemodynamic instability due to pelvic fracture in three regional trauma centres in Korea.

PATIENTS AND METHODS

Three regional trauma centres participated in this study, and 157 patients who were admitted between January 2015 and December 2018 were enroled. Clinical data were collected prospectively as part of the Korean trauma data bank and were analysed retrospectively.

RESULTS

The mean age was 59.3 years, and 107 of 157 (68.2%) were male patients. The most common cause of injury was auto-pedestrian accidents, followed by falls and motor vehicle crashes. The mean admission systolic blood pressure and serum lactate level were 86.7 mmHg and 6.68 mmol/L, respectively. Twenty-four patients (15.3%) had a cardiac arrest in the emergency department (ED). The mean injury severity score was 39.1, and the mean probability of survival (Trauma and Injury Severity Score) was 48.7%. Sixty-six patients (42%) underwent pelvic angiography; 89 (56.7%), preperitoneal pelvic packing (PPP); 27 (17.2%), resuscitative endovascular balloon occlusion of the aorta (REBOA); 20 (12.7%), pelvic external fixation (PEF); and 13 patients (8.3%), internal iliac artery ligation (IIAL). Seventy-three patients (46.5%) died, including 40 (25.5%) who died from acute haemorrhage. With each year, the rates of REBOA and pelvic binder use continued to increase (p<0.001 and p = 0.005, respectively), but the number of PEF cases significantly decreased (p = 0.006). Age, initial lactate, low revised trauma score (RTS), combined abdominal injury, REBOA, and 4-hour requirement of packed red blood cells were independent risk factors associated with mortality, whereas during the period of 2017 and 2018, there were protective factors. The risk factors of mortality due to haemorrhage were cardiac arrest in the ED, RTS, combined chest and abdominal injuries, and IIAL.

CONCLUSIONS

Since the establishment of regional trauma centres, the clinical outcomes of patients with hemodynamic instability due to pelvic fracture have significantly improved. As a haemostatic procedure for these patients, PEF has been used less frequently, while pelvic binder and REBOA showed significant increase in their use.

The VWF/LRP4/αVβ3-axis represents a novel pathway regulating proliferation of human vascular smooth muscle cells

AIMS

Von Willebrand factor (VWF) is a plasma glycoprotein involved in primary haemostasis, while also having additional roles beyond haemostasis namely in cancer, inflammation, angiogenesis, and potentially in vascular smooth muscle cell (VSMC) proliferation. Here, we addressed how VWF modulates VSMC proliferation and investigated the underlying molecular pathways and the in vivo pathophysiological relevance.

METHODS AND RESULTS

VWF induced proliferation of human aortic VSMCs and also promoted VSMC migration. Treatment of cells with a siRNA against αv integrin or the RGT-peptide blocking αvβ3 signalling abolished proliferation. However, VWF did not bind to αvβ3 on VSMCs through its RGD-motif. Rather, we identified the VWF A2 domain as the region mediating binding to the cells. We hypothesized the involvement of a member of the LDL-related receptor protein (LRP) family due to their known ability to act as co-receptors. Using the universal LRP-inhibitor receptor-associated protein, we confirmed LRP-mediated VSMC proliferation. siRNA experiments and confocal fluorescence microscopy identified LRP4 as the VWF-counterreceptor on VSMCs. Also co-localization between αvβ3 and LRP4 was observed via proximity ligation analysis and immuno-precipitation experiments. The pathophysiological relevance of our data was supported by VWF-deficient mice having significantly reduced hyperplasia in carotid artery ligation and artery femoral denudation models. In wild-type mice, infiltration of VWF in intimal regions enriched in proliferating VSMCs was found. Interestingly, also analysis of human atherosclerotic lesions showed abundant VWF accumulation in VSMC-proliferating rich intimal areas.

CONCLUSION

VWF mediates VSMC proliferation through a mechanism involving A2 domain binding to the LRP4 receptor and integrin αvβ3 signalling. Our findings provide new insights into the mechanisms that drive physiological repair and pathological hyperplasia of the arterial vessel wall. In addition, the VWF/LRP4-axis may represent a novel therapeutic target to modulate VSMC proliferation.

Gender-specific differences in haemostatic parameters and their influence on blood loss in bimaxillary surgery

Objective

The objectives of this prospective cohort study were to establish gender-related differences in blood loss and haemostatic profiles associated with bimaxillary surgery. In addition, we aimed to identify if any gender differences could be established which might help predict blood loss volume.

Materials and methods

Fifty-four patients (22 males; 32 females) undergoing bimaxillary surgery for skeletal dentofacial deformities were eligible for inclusion. Blood samples were taken 1 day preoperatively and 48 h postoperatively for detailed gender-specific coagulation analysis incorporating global coagulation assays (endogenous thrombin potential) and specific coagulation parameters. Blood loss was measured at two different time points: (1) the end of surgery, visible intraoperative blood loss (IOB) using ‘subtraction method’; and (2) 48 h postoperatively perioperative bleeding volume (CBL-48 h) using ‘haemoglobin-balance method’ and Nadler’s formula. Correlation and regression analyses were performed to identify relevant parameters affecting the amount of blood loss.

Results

Significant differences in IOB and CBL-48 h were observed (p < 0.001). Men had higher IOB versus women, lacking statistical significance (p = 0.056). In contrast, men had significantly higher CLB-48 h (p = 0.019). Reduced CBL-48 h was shown to be most closely associated with the level of Antithrombin-III being decreased in females.

Conclusions

Male gender is associated with higher IOB and CBL-48 compared with females. Gender does not affect IOB regarding haemostatic profile but does correlate strongly with procedure length. Conversely, CBL-48 is closely associated with gender-specific imbalances in the anticoagulant system.

Clinical relevance

Knowledge of gender-related differences will help clinicians establish predictive factors regarding excessive blood loss in orthognathic surgery and identify at-risk patients.

Continuum modeling of thrombus formation and growth under different shear rates

Obstruction of blood flow due to thrombosis is a major cause of ischemic stroke, myocardial infarction, and in severe cases, mortality. In particular, in blood wetting medical devices, thrombosis is a common reason for failure. The prediction of thrombosis by understanding signaling pathways using computational models, lead to identify the risk of thrombus formation in blood-contacting devices and design improvements. In this study, a mathematical model of thrombus formation and growth is presented. A biochemical model of platelet activation and aggregation is developed to predict thrombus size and shape at the site of vascular injury. Computational fluid dynamics using the finite volume method is employed to compute the velocity and pressure fields which are influenced by the growing thrombi. The passive transport of platelets, agonists, the platelet activation kinetics, their adhesion to the growing thrombi and embolization of platelets are solved by a fully coupled set of convection-diffusion-reaction equations. The thrombogenic surface representing blood-contacting material or injured blood vessel was incorporated into the model as a surface flux boundary condition to initiate thrombus formation. The blood is considered as a Newtonian fluid, while the thrombus is treated as a porous medium. The results are compared with in vitro experiments of a microfluidic chamber at an initial inlet venous shear rate of 200s^-1 using a pressure-inlet boundary condition. The thrombus development due to agonist concentrations and change in the shear rate as well as thromboembolism for this benchmark problem is successfully computed. Furthermore, to extend the current model to a physiologically relevant configuration, thrombus formation in a blood tube is simulated. Two different heterogeneous reaction rates for platelet aggregation are used to simulate thrombus growth under a constant inlet flow rate. The findings show that the thrombus shape can be substantially altered by the hemodynamic conditions, increase in the shear rate and due to the combined effects of shear induced platelet activation and the heterogeneous reaction rates. It is also concluded that the model is able to predict thrombus formation in different physiological and pathological hemodynamics.

Bioinspired artificial platelets: past, present and future

Platelets are anucleate blood cells produced from megakaryocytes predominantly in the bone marrow and released into blood circulation at a healthy count of 150,000-400,00 per μL and circulation lifespan of 7-9 days. Platelets are the first responders at the site of vascular injury and bleeding, and participate in clot formation via injury site-specific primary mechanisms of adhesion, activation and aggregation to form a platelet plug, as well as secondary mechanisms of augmenting coagulation via thrombin amplification and fibrin generation. Platelets also secrete various granule contents that enhance these mechanisms for clot growth and stability. The resultant clot seals the injury site to stanch bleeding, a process termed as hemostasis. Due to this critical role, a reduction in platelet count or dysregulation in platelet function is associated with bleeding risks and hemorrhagic complications. These scenarios are often treated by prophylactic or emergency transfusion of platelets. However, platelet transfusions face significant challenges due to limited donor availability, difficult portability and storage, high bacterial contamination risks, and very short shelf life (~5-7 days). These are currently being addressed by a robust volume of research involving reduced temperature storage and pathogen reduction processes on donor platelets to improve shelf-life and reduce contamination, as well as bioreactor-based approaches to generate donor-independent platelets from stem cells in vitro. In parallel, a complementary research field has emerged that involves the design of artificial platelets utilizing biosynthetic particle constructs that functionally emulate various hemostatic mechanisms of platelets. Here, we provide a comprehensive review of the history and the current state-of-the-art artificial platelet approaches, along with discussing the translational opportunities and challenges.

The role of the calibrated automated thrombogram in neonates: describing mechanisms of neonatal haemostasis and evaluating haemostatic drugs

Premature infants are at high risk of haemorrhage and thrombosis. Our understanding of the differences between the neonatal and adult haemostatic system is evolving. There are several limitations to the standard coagulation tests used in clinical practice, and there is currently a lack of evidence to support many of the transfusion practices in neonatal medicine. The evaluation of haemostasis is particularly challenging in neonates due to their limited blood volume. The calibrated automated thrombogram (CAT) is a global coagulation assay, first described in 2002, which evaluates both pro- and anti-coagulant pathways in platelet-rich or platelet-poor plasma. In this review, the current applications and limitations of CAT in the neonatal population are discussed.Conclusion: CAT has successfully elucidated several differences between haemostatic mechanisms in premature and term neonates compared with adults. Moreover, it has been used to evaluate the effect of a number of haemostatic drugs in a pre-clinical model. However, the lack of evidence of CAT as an accurate predictor of neonatal bleeding, blood volume required and the absence of an evidence-based treatment algorithm for abnormal CAT results limit its current application as a bedside clinical tool for the evaluation of sick neonates. What is Known: • The Calibrated automated thrombogram (CAT) is a global coagulation assay which evaluates pro- and anti-coagulant pathways. • CAT provides greater information than standard clotting tests and has been used in adults to evaluate bleeding risk. What is New: • This review summarises the physiological differences in haemostasis between neonates and adults described using CAT. • The haemostatic effect of several drugs has been evaluated in neonatal plasma using CAT.

PI3K Isoform Signalling in Platelets

Platelets are unique anucleated blood cells that constantly patrol the vasculature to seal and prevent injuries in a process termed haemostasis. Thereby they rapidly adhere to the subendothelial matrix and recruit further platelets, resulting in platelet aggregates. Apart from their central role in haemostasis, they also kept some of their features inherited by their evolutionary ancestor-the haemocyte, which was also involved in immune defences. Together with leukocytes, platelets fight pathogenic invaders and guide many immune processes. In addition, they rely on several signalling pathways which are also relevant to immune cells. Among these, one of the central signalling hubs is the PI3K pathway. Signalling processes in platelets are unique as they lack a nucleus and therefore transcriptional regulation is absent. As a result, PI3K subclasses fulfil distinct roles in platelets compared to other cells. In contrast to leukocytes, the central PI3K subclass in platelet signalling is PI3K class Iβ, which underlines the uniqueness of this cell type and opens new ways for potential platelet-specific pharmacologic inhibition. An overview of platelet function and signalling with emphasis on PI3K subclasses and their respective inhibitors is given in this chapter.

The potential of chitosan-based haemostats for use in neurosurgical setting - Literature review

Haemorrhage is a major nuance in neurosurgery since blood can distort the surgeon's field of view and increase the risk of post-operative complications. Currently a variety of commercially available haemostats have been approved for use in neurosurgery, but they have caveats to their use in the brain, including, localised tissue compression, neural toxicity, induce immune reaction or form thrombus within the vessel. Thus, there is a need for haemostats that are efficacious and safe for application on brain and spinal tissue. Chitosan is a naturally occurring bio-polymer that is found on the exoskeleton of arthropods and the cell wall of fungi. Chitosan has been shown to accelerate haemostasis through a myriad of physiological pathways. These findings have led to the development of multiple chitosan-based haemostats, for use in peripheral human tissue. Although, clinical data regarding the use of chitosan-based haemostats in the brain is lacking, a range on in vivo studies have proven chitosan to be efficacious and safe in managing neurosurgical bleeds. Similarly, literature comparing chitosan-based haemostats with commercial haemostats used commonly in neurosurgery, have all demonstrated chitosan to be the superior agent. Additionally, clinical trials of chitosan-based haemostat used in peripheral tissue have all demonstrated chitosan to be safe for human use. The marriage of these findings indicates that the safety and superior efficacy of chitosan-based haemostat, makes it a potentially suitable haemostat for use in neurosurgical setting. However, further research pertaining to the clinical use of chitosan-based haemostat within the central nervous system needs to be conducted.

Activation of canine neutrophils by platelet-activating factor

Neutrophils are essential for innate immunity as the first line of defence. Neutrophils act as phagocytic white blood cells to kill bacteria and other microorganisms. A strong respiratory burst of neutrophils, dependent on reactive oxygen species, is produced during phagocytosis. Platelet-activating factor (PAF) is a signalling molecule with several prominent roles in tissue injury, inflammation, and platelet aggregation. However, the detailed mechanisms and intracellular signalling pathways involved in PAF-mediated neutrophil activation remain unclear. Here, we investigated the effect of PAF on changes in calcium concentration ([Ca²⁺]_i) and oxygen radical (O₂^-) generation in activating canine neutrophils. We further evaluated these effects of PAF with inhibition of G protein-coupled receptors using the specific inhibitor suramin. Blood samples were collected from a total of five dogs and neutrophils were isolated. PAF stimulation of canine neutrophils caused an increase in [Ca²⁺]_i as well as the generation of O₂^-, and the PAF receptor was sensitive to suramin. The results suggested that PAF stimulation of canine neutrophils may cause Ca²⁺ influx from the endoplasmic reticulum into the cytoplasm (as the first wave) and then trigger store-operated Ca²⁺ entry (as the second wave), which is an important intracellular signal transduction pathway for neutrophil activation. Furthermore, O₂^- generation by PAF stimulation may depend on the intracellular signalling pathway, with increasing inositol trisphosphate levels and [Ca²⁺]_i via G protein-coupled receptors. The finding that PAF-activating platelet aggregation is involved in canine neutrophil activation suggests a close relationship between haemostasis and neutrophil activation in dogs, offering new insight into the response to infection.

Aquaporins in platelet function

Structurally, aquaporins (AQPs) are small channel proteins with monomers of ~ 30 kDa that are assembled as tetramers to form pores on cell membranes. Aquaporins mediate the conduction of water but at times also small solutes including glycerol across cell membranes and along osmotic gradients. Thirteen isoforms of AQPs have been reported in mammalian cells, and several of these are likely expressed in platelets. Osmotic swelling mediated by AQP1 sustains the calcium entry required for platelet phosphatidylserine exposure and microvesiculation, through calcium permeable stretch-activated or mechanosensitive cation channels. Notably, deletion of AQP1 diminishes platelet procoagulant membrane dynamics in vitro and arterial thrombosis in vivo, independent of platelet granule secretion and without affecting hemostasis. Water entry into platelets promotes procoagulant activity, and AQPs may also be critical for the initiation and progression of venous thrombosis. Platelet AQPs may therefore represent valuable targets for future development of a new class of antithrombotics, namely, anti-procoagulant antithrombotics, that are mechanistically distinct from current antithrombotics. However, the structure of AQPs does not make for easy targeting of these channels, hence they remain elusive drug targets. Nevertheless, thrombosis data in animal models provide compelling reasons to continue the pursuit of AQP-targeted antithrombotics. In this review, we discuss the role of aquaporins in platelet secretion, aggregation and procoagulation, the challenge of drugging AQPs, and the prospects of targeting AQPs for arterial and venous antithrombosis.

Effectiveness of Cross Double McDonald Cerclage for Intractable Bleeding from a Cervical Varix in Pregnant Women

Cervical varix during pregnancy is a rare condition, and standard management for bleeding from a varix has not been established. We performed cross double cervical cerclage and effectively stopped bleeding. A 41-year-old female had a twin pregnancy. The development of a cervical varix was observed during pregnancy and bleeding from ruptured varix started at 20 weeks of gestation. We performed surgical hemostasis by cervical cerclage. In the first cerclage, we could not stop the bleeding from the varix. For further restriction of blood supply to the cervical varix, we performed a second cerclage in a crossed position on a deeper side of the vagina than the first cerclage. Then the bleeding completely stopped and there was no bleeding until delivery. The "cross double McDonald cerclage" performed in our patient may be a useful modified cerclage method for stopping intractable bleeding from the cervix during pregnancy.

A Case of Acquired von Willebrand Syndrome Complicated by Acute Myelomonocytic Leukemia

We here report a 21-year-old male who presented with acute myelomonocytic leukemia (AMML) associated with acquired von Willebrand syndrome (AVWS). To our knowledge, this is the first case of AVWS caused by AMML. In our case, following remission-induction chemotherapy combined with idarubicin and cytarabine, the patient showed remarkable improvement of bleeding symptoms due to AVWS. Moreover, after an allogeneic stem cell transplantation from a sibling donor, both AMML and AVWS maintain complete remission.

Is radial artery occlusion and local vascular complications following transradial coronary procedures affected by the type of haemostasis device used? A non-inferiority Randomized Controlled Trial (RadCom trial)

AIMS

Vascular access site complications following transradial coronary procedures are less common and severe compared to femoral approach. Radial artery occlusion is considered the main adverse effect. As radial access is gaining more acknowledgement, complication awareness, and understanding is important. The aim was to assess complication rates following transradial coronary procedures and to compare two radial compression devices in a non-inferiority randomized controlled trial.

METHODS AND RESULTS

Four hundred and ninety-nine patients were randomized to radial compression with a new device (RY Stop, n = 248) or the reference device (TR Band, n = 251) following transradial coronary procedures. Radial artery occlusion persistent at 90 days was the primary endpoint. Discomfort and accounts of vascular complications at access site were secondary endpoints. Radial artery occlusion was observed in 5% (n = 26) for the entire cohort with no difference between groups (RY Stop 6% vs. TR Band 5%; P = 0.69). Patients overall reported low levels of discomfort and the median scores were similar in both groups; RY Stop: 7 vs. TR Band: 10 (P = 0.90). There were few incidents of bleeding (7%), however, they were significantly more frequent with the RY Stop (12%) than with the TR Band (3%; P = 0.001). Few patients (4%) developed access site haematomas, and the incidence was similar in the two groups (P = 0.98).

CONCLUSION

We observed a radial artery occlusion rate of 5% at 90 days post-procedure. Access site discomfort and vascular complication rates were low. Overall, the RY Stop compression device was not inferior to the TR Band except occurrences of bleeding.

Common haemostatic techniques used in surgical practice

Intraoperative bleeding can be difficult to manage and is associated with worse patient outcomes. Good intraoperative haemostasis by the surgeon is a key factor in ensuring a bloodless field and reducing intraoperative blood loss. There is a myriad of mechanical, thermal and energy-based techniques available to use, each of which has their own benefits and drawbacks. The decision of which to use will depend on patient and procedural factors as well as the surgeon's preference. This article reviews techniques commonly used in surgical practice to maintain intraoperative haemostasis.

PuraStat in gastrointestinal bleeding: results of a prospective multicentre observational pilot study

Background

A recently developed haemostatic peptide gel for endoscopic application has been introduced to improve the management of gastrointestinal bleeding. The aim of this pilot study was to evaluate the feasibility, safety, efficacy and indication profiles of PuraStat in a clinical setting.

Methods

In this prospective observational multicentre pilot study, patients with acute non-variceal gastrointestinal bleeding (upper and lower) were included. Primary and secondary application of PuraStat was evaluated. Haemoglobin, prothrombin time, platelets and transfusion behaviour were documented before and after haemostasis. The efficacy of PuraStat was assessed during the procedure, at 3 days and 1 week after application.

Results

111 patients with acute gastrointestinal bleeding were recruited into the study. 70 percent (78/111) of the patients had upper gastrointestinal bleeding and 30% (33/111) had lower gastrointestinal bleeding. After primary application of PuraStat, initial haemostatic success was achieved in 94% of patients (74/79, 95% CI 88–99%), and in 75% of the patients when used as a secondary haemostatic product, following failure of established techniques (24/32, 95% CI 59–91%). The therapeutic success rates (absence of rebleeding) after 3 and 7 days were 91% and 87% after primary use, and 87% and 81% in all study patients. Overall rebleeding rate at 30 day follow-up was 16% (18/111). In the 5 patients who finally required surgery (4.5%), PuraStat allowed temporary haemostasis and stabilisation.

Conclusions

PuraStat expanded the therapeutic toolbox available for an effective treatment of gastrointestinal bleeding sources. It could be safely applied and administered without complications as a primary or secondary therapy. PuraStat may additionally serve as a bridge to surgery in order to achieve temporary haemostasis in case of refractory severe bleeding, possibly playing a role in preventing immediate emergency surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-021-08589-6.

Novel autologous, high concentrated fibrin as advanced hemostatic agent for coronary surgery

BACKGROUND

Variability in transfusion outcomes and excessive postoperative bleeding represents a significant problem in cardiac surgery. The effort to reduce bleeding complications and transfusion outcomes is desirable. Our study investigated the feasibility of reducing bleeding complications and transfusion requirements by applying perioperatively prepared autologous bio-regenerative fibrin sealant.

METHODS

A prospective, case-control study enrolled 74 patients undergoing coronary artery bypass grafting by a single surgeon. Patients in the control group (N = 43), received traditional methods of hemostasis, while patients in the experimental group (N = 31) were treated additionally with autologous bio-regenerative fibrin.

RESULTS

Patients were well-matched with regard to basic demographic, laboratory and procedural data. Allogeneic blood transfusion requirement in control group was 39.5 % (17 of 43 patients), compared to 6.5 % (2 of 31 patients) in treated group (p < 0,001). The lower infection rate in the experimental group was also noted. No safety issues were identified during the preparation and application process.

CONCLUSION

Autologous bio-regenerative fibrin can be safely prepared, with no time consuming, and was demonstrated to be a useful tool to decrease allogeneic blood transfusion requirements following elective coronary artery bypass grafting surgery. A prospective randomized trial is needed to confirm these findings.

Off Label Use of StarClose for Superior Gluteal Artery Puncture Closure Following Embolisation of an Internal Iliac Artery Type II Endoleak

Introduction

Embolisation of type II internal iliac artery endoleaks is challenging given limited options for obtaining transarterial access and for achieving access site haemostasis.

Report

An 86 year old woman who had undergone endovascular repair for an aorto-iliac aneurysm was found to have serial enlargement of the left common iliac artery portion of the aneurysm observed over a period of two years. At the time of the initial repair, the left internal iliac artery was embolised using coils, and then was covered by extending the iliac limb endoprosthesis into the external iliac artery. However, computed tomography angiography showed recanalisation of the previously coiled left internal iliac artery, thus allowing contrast to flow into the left common iliac aneurysm sac. Given that the internal iliac artery origin was covered and there was no visible collateral pathway, direct puncture of the superior gluteal artery was selected to access the left internal iliac artery in a retrograde fashion. This presented a challenge in terms of achieving haemostasis given the deep position of the arterial access site, which was unlikely to be amenable to manual compression. Off label StarClose was chosen for closure of the superior gluteal arterial access, with successful haemostasis and preserved patency of the vessel.

Discussion

Off label StarClose was used successfully to obtain haemostasis after obtaining percutaneous transgluteal access to the superior gluteal artery in order to embolise a type II endoleak arising from the internal iliac artery. Keywords: StarClose; Iliac artery type II endoleak; Arterial closure device; Haemostasis; Superiorgluteal artery

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Off-label use of StarClose in a location not amenable to manual compression.

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Arterial preservation can avoid distal ischaemia and permit vascular re-access.

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Vascular closure devices should be investigated in other difficult anatomic sites.

"Millefeuille Technique" by Using Excised Intimal Layers in Repair of Type A Aortic Dissection

Surgical outcomes for acute Type A aortic dissection (AAD) have dramatically improved in recent years due to prompt diagnosis, improved surgical technique and perioperative management. A single needle hole can become a new entry point in AAD cases with such a fragile wall, so a mixed technique using minimal surgical stitches and glue is required for a good outcome. The 'Millefeuille' technique involves multiple layers with a prosthetic graft, intimal layer, additionally inserted surplus intimal layer with BioGlue, adventitial layer, and felt. This technique may help to prevent needle hole re-entry.

Acquired haemophilia in patients with malignant disease: A case report

BACKGROUND

Acquired haemophilia is a rare coagulation disorder characterized by autoantibodies against coagulation factor VIII leading to severe and potentially life-threatening haemorrhages. The underlying disorder causing the development of an autoimmune phenomenon is not always known, but 10%-15% could be linked to malignancies. Patients with cancer who require surgical resection represent a treatment challenge not solely due to increased risk of bleeding but also due to adverse events of immunosuppressive therapy.

CASE SUMMARY

We present the case of a 67-year-old man with non-metastatic adenocarcinoma of the distal bile duct who developed concomitant acquired haemophilia a month after having been diagnosed with malignant disease. Haemostasis was established with recombinant activated factor VII, and immunosuppressive therapy was started immediately. An extensive surgical procedure was performed in order to remove the cancer and, therefore, eliminate the inhibitory autoantibodies. Due to a complicated postoperative course, relatively short period of treatment and likelihood of micrometastases, no improvement in the patient’s status was observed. Diagnosis and treatment of acquired haemophilia as well as other coagulation disorders in patients with cancer are discussed.

CONCLUSION

Prompt diagnosis of acquired haemophilia is required in order to start appropriate treatment and reduce mortality. Among patients with cancer, other causes of abnormal bleeding related to malignancy should be considered.

Diagnosis of primary hyperfibrinolysis and in vitro investigation of the inhibitory effects of tranexamic acid in a group of dogs with sarcomas - A pilot study

Primary hyperfibrinolysis is not well characterised in canine cancer. This prospective case-control pilot study aimed to evaluate tissue plasminogen activator-modified thromboelastography (tPA-TEG) for diagnosis of primary hyperfibrinolysis in dogs with cancer and establish the in vitro therapeutic concentration of tranexamic acid (TXA). Nine dogs with sarcomas and normocoagulable thromboelastograms and 11 healthy dogs were included. For each a whole blood tPA-TEG, and four tPA-TEGs with added TXA in different concentrations were analysed. Lysis percentage at 30/60 min following maximal amplitude (LY30/60), clot lysis index (CL30/60), maximum rate of lysis (MRL), and total lysis (L) were investigated as diagnostic parameters of primary hyperfibrinolysis. In vitro TXA concentrations needed to inhibit 50% (IC50) and 90% (IC90) of the fibrinolytic potential were compared between groups. Significant primary hyperfibrinolysis (LY30 (P = 0.0001), LY60 (P = 0.003), CL30 (P = 0.01), and L (P = 0.02)) was observed in dogs with sarcomas. IC50 and IC90 of in vitro TXA for normalizing LY30 were 13.34 (SE 1.52) and 31.10 (SE 3.01) mg/L for dogs with sarcomas and 4.41 (SE 5.84) and 20.00 (SE 6.18) mg/L for healthy dogs. IC50 and IC90 for normalizing LY60 were 22.18 (SE 1.27) and 58.94 (SE 5.47) mg/L for dogs with sarcomas and 11.25 (SE 2.82) and 56.20 (SE 11.61) mg/L for healthy dogs. The IC50 for LY60 was significantly increased for dogs with sarcomas (P = 0.0003). Primary hyperfibrinolysis was documented by tPA-TEG in dogs with sarcomas. In vitro IC50 and IC90 for TXA were established. Clinical studies are required to establish therapeutic dosages in vivo.

Managing vascular access and closure for percutaneous mechanical circulatory support

Even with current generation mechanical circulatory support (MCS) devices, vascular complications are still considerable risks in MCS that influence patients’ recovery and survival. Hence, efforts are made to reduce vascular trauma and obtaining safe and adequate arterial access using state-of-the-art techniques is one of the most critical aspects for optimizing the outcomes and efficiency of percutaneous MCS. Femoral arterial access remains necessary for numerous large-bore access procedures and is most commonly used for MCS, whereas percutaneous axillary artery access is typically considered an alternative for the delivery of MCS, especially in patients with severe peripheral artery disease. This article will address the access, maintenance, closure and complication management of large-bore femoral access and concisely describe alternative access routes.