Clinical Use of the Activated Partial Thromboplastin Time and Prothrombin Time for Screening

A 4D printed nanoengineered super bioactive hydrogel scaffold with programmable deformation for potential bifurcated vascular channel construction

Four-dimensional (4D) printing of hydrogels enabled the fabrication of complex scaffold geometries out of static parts. Although current 4D fabrication strategies are promising for creating vascular parts such as tubes, developing branched networks or tubular junctions is still challenging. Here, for the first time, a 4D printing approach is employed to fabricate T-shaped perfusable bifurcation using an extrusion-based multi-material 3D printing process. An alginate/methylcellulose-based dual-component hydrogel system (with defined swelling behavior) is nanoengineered with carbonized alginate (∼100 nm) to introduce anti-oxidative, anti-inflammatory, and anti-thrombotic properties and shape-shifting properties. A computational model to predict shape deformations in the printed hydrogels with defined infill angles was designed and further validated experimentally. Shape deformations of the 3D-printed flat sheets were achieved by ionic cross-linking. An undisrupted perfusion of a dye solution through a T-junction with minimal leakage mimicking blood flow through vessels is also demonstrated. Moreover, human umbilical vein endothelial and fibroblast cells seeded with printed constructs show intact morphology and excellent cell viability. Overall, the developed strategy paves the way for manufacturing self-actuated vascular bifurcations with remarkable anti-thrombotic properties to potentially treat coronary artery diseases.

Investigation of coagulation and proteomics profiles in symptomatic feline hypertrophic cardiomyopathy and healthy control cats

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a crucial heart disease in cats. The clinical manifestations of HCM comprise pulmonary edema, dyspnea, syncope, arterial thromboembolism (ATE), and sudden cardiac death. D-dimer and prothrombin time (PT) are powerful biomarkers used to assess coagulation function. Dysregulation in these two biomarkers may be associated with HCM in cats. This study aims to assess D-dimer levels, PT, and proteomic profiling in healthy cats in comparison to cats with symptomatic HCM.

RESULTS

Twenty-nine client-owned cats with HCM were enrolled, including 15 healthy control and 14 symptomatic HCM cats. The D-dimer concentration and PT were examined. Proteomic analysis was conducted by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In symptomatic cats, D-dimer levels were statistically significantly higher (mean ± SEM: 372.19 ng/ml ± 58.28) than in healthy cats (mean ± SEM: 208.54 ng/ml ± 10.92) with P-value of less than 0.01, while PT was statistically significantly lower in symptomatic cats (mean ± SEM: 9.8 s ± 0.15) compared to healthy cats (mean ± SEM: 11.08 s ± 0.23) with P-value of less than 0.0001. The proteomics analysis revealed upregulation of integrin subunit alpha M (ITGAM), elongin B (ELOB), and fibrillin 2 (FBN2) and downregulation of zinc finger protein 316 (ZNF316) and ectonucleoside triphosphate diphosphohydrolase 8 (ENTPD8) in symptomatic HCM cats. In addition, protein-drug interaction analysis identified the Ras signaling pathway and PI3K-Akt signaling pathway.

CONCLUSIONS

Cats with symptomatic HCM have higher D-dimer and lower PT than healthy cats. Proteomic profiles may be used as potential biomarkers for the detection and management of HCM in cats. The use of D-dimer as a biomarker for HCM detection and the use of proteomic profiling for a better understanding of disease mechanisms remain to be further studied in cats.

Construction and validation of risk prediction models for pulmonary embolism in hospitalized patients based on different machine learning methods

Objective

This study aims to apply different machine learning (ML) methods to construct risk prediction models for pulmonary embolism (PE) in hospitalized patients, and to evaluate and compare the predictive efficacy and clinical benefit of each model.

Methods

We conducted a retrospective study involving 332 participants (172 PE positive cases and 160 PE negative cases) recruited from Guangdong Medical University. Participants were randomly divided into a training group (70%) and a validation group (30%). Baseline data were analyzed using univariate analysis, and potential independent risk factors associated with PE were further identified through univariate and multivariate logistic regression analysis. Six ML models, namely Logistic Regression (LR), Decision Tree (DT), Random Forest (RF), Naive Bayes (NB), Support Vector Machine (SVM), and AdaBoost were developed. The predictive efficacy of each model was compared using the receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC). Clinical benefit was assessed using decision curve analysis (DCA).

Results

Logistic regression analysis identified lower extremity deep venous thrombosis, elevated D-dimer, shortened activated partial prothrombin time, and increased red blood cell distribution width as potential independent risk factors for PE. Among the six ML models, the RF model achieved the highest AUC of 0.778. Additionally, DCA consistently indicated that the RF model offered the greatest clinical benefit.

Conclusion

This study developed six ML models, with the RF model exhibiting the highest predictive efficacy and clinical benefit in the identification and prediction of PE occurrence in hospitalized patients.

Head-to-head ex vivo comparison of clinically used direct anticoagulant drugs

An imbalance in coagulation is associated with cardiovascular events. For prevention and treatment, anticoagulants, currently mainly xabans and gatrans, are used. The purpose of the present study was to provide a head-to-head comparison since there are no studies directly evaluating these novel anticoagulants. An additional aim was to find whether selected anthropological and biochemical factors can affect their anticoagulant properties as they are used in fixed doses. In this cross-sectional study, blood from 50 generally healthy donors was collected, and coagulation responses to dabigatran, argatroban, rivaroxaban, and apixaban, at a concentration of 1 μM, were analyzed. Heparin was used as a positive control. Prothrombin time (PT) expressed as international normalized ratio (INR) and activated partial thromboplastin time (aPTT) were measured and compared. Rivaroxaban was the most active according to PT/INR while argatroban according to aPTT. The ex vivo anticoagulant effect measured by INR correlated inversely with body mass index (BMI) in all four anticoagulants tested. Shortening of aPTT was associated with higher cholesterol and triglyceride levels. No sex-related differences were observed in response to the anticoagulant treatments. As this was an ex vivo study and pharmacokinetic factors were not included, the influence of BMI is of high therapeutic importance.

Association of prothrombin time, thrombin time and activated partial thromboplastin time levels with preeclampsia: a systematic review and meta-analysis

BACKGROUND

Preeclampsia (PE), an obstetric disorder, remains one of the leading causes of maternal and infant mortality worldwide. In individuals with PE, the coagulation-fibrinolytic system is believed to be among the most significantly impacted systems due to maternal inflammatory responses and immune dysfunction. Therefore, this systematic review and meta-analysis aimed to assess the association of prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (APTT) levels with preeclampsia.

METHODS

This systematic review and meta-analysis was conducted in accordance with the PRISMA guidelines. Articles relevant to the study, published from July 26, 2013, to July 26, 2023, were systematically searched across various databases including PubMed, Scopus, Embase, and Hinari. The methodological quality of the articles was evaluated using the Joanna Briggs Institute critical appraisal checklist. Utilizing Stata version 14.0, a random-effects model was employed to estimate the pooled standardized mean difference (SMD) along with the respective 95% CIs. The I2 statistics and Cochrane Q test were utilized to assess heterogeneity, while subgroup analyses were performed to explore its sources. Furthermore, Egger's regression test and funnel plot were employed to assess publication bias among the included studies.

RESULTS

A total of 30 articles, involving 5,964 individuals (2,883 with PE and 3,081 as normotensive pregnant mothers), were included in this study. The overall pooled SMD for PT, APTT, and TT between PE and normotensive pregnant mothers were 0.97 (95% CI: 0.65-1.29, p < 0.001), 1.05 (95% CI: 0.74-1.36, p < 0.001), and 0.30 (95% CI: -0.08-0.69, p = 0.11), respectively. The pooled SMD indicates a significant increase in PT and APTT levels among PE patients compared to normotensive pregnant mothers, while the increase in TT levels among PE patients was not statistically significant.

CONCLUSIONS

The meta-analysis underscores the association between PE and prolonged PT and APTT. This suggests that evaluating coagulation parameters like PT, APTT, and TT in pregnant women could offer easily accessible and cost-effective clinical indicators for assessing PE. However, multicenter longitudinal studies are needed to evaluate their effectiveness across various gestational weeks of pregnancy.

A retrospective study of the prevalence of isolated prolongation of activated partial thromboplastin time in the preoperative setting

BACKGROUND

Isolated prolongation of activated partial thromboplastin time (APTT) has various causes including inheritable bleeding disorders, and has medical significance as it can lead to the cancelation of surgery. However, even an emergency surgery can be conducted in a patient presenting with severe APTT prolongation, provided careful evaluation and appropriate measures are taken. Hence, the identification of the underlying etiology of the prolonged APTT is crucial. To date, little evidence exists regarding the prevalence of isolated APTT prolongation in Japanese patients undergoing surgery. Herein, we aimed to clarify the prevalence of isolated prolongation of APTT in the preoperative setting and to identify the reasons underlying isolated, severely prolonged APTT.

METHODS

Preoperative coagulation data of all elective and emergent patients who presented to the anesthetic department between January 1, 2020, and June 30, 2023, were retrospectively collected. Isolated prolongation of APTT was defined as an APTT ≥ 37 s with an international normalized ratio of prothrombin time < 1.2. The underlying etiology of the patient with isolated, severely prolonged APTT (≥ 46 s) was investigated, and canceled surgical procedures in relation to the isolated APTT prolongation were searched.

RESULTS

Overall, 10,684 measurements from 9413 patients were included, of which 725 (6.8%) were identified as having isolated APTT prolongation. The reasons for the severely prolonged APTT (n = 60) were miscellaneous, with the most frequently detected etiology being antiphospholipid antibody positivity. Preoperative isolated APTT prolongation contributed to the cancellation of surgery in elective five cases.

CONCLUSIONS

We clarified the prevalence of preoperative isolated prolongation of APTT. The presence of antiphospholipid antibody was the most frequently detected etiology of the patient with isolated, severely prolonged APTT. The present study provides an important dataset regarding the isolated prolongation of APTT in East Asian patients undergoing surgery.

Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic site

Background

Salvianolic acid B (SAB) is a major component of Salvia miltiorrhiza root (Danshen), widely used in East/Southeast Asia for centuries to treat cardiovascular diseases. Danshen depside salt, 85% of which is made up of SAB, is approved in China to treat chronic angina. Although clinical observations suggest that Danshen extracts inhibited arterial and venous thrombosis, the exact mechanism has not been adequately elucidated.

Objective

To delineate the antithrombotic mechanisms of SAB.

Methods

We applied platelet aggregation and coagulation assays, perfusion chambers, and intravital microscopy models. The inhibition kinetics and binding affinity of SAB to thrombin are measured by thrombin enzymatic assays, intrinsic fluorescence spectrophotometry, and isothermal titration calorimetry. We used molecular in silico docking models to predict the interactions of SAB with thrombin.

Results

SAB dose-dependently inhibited platelet activation and aggregation induced by thrombin. SAB also reduced platelet aggregation induced by adenosine diphosphate and collagen. SAB attenuated blood coagulation by modifying fibrin network structures and significantly decreased thrombus formation in mouse cremaster arterioles and perfusion chambers. The direct SAB-thrombin interaction was confirmed by enzymatic assays, intrinsic fluorescence spectrophotometry, and isothermal titration calorimetry. Interestingly, SAB shares key structural similarities with the trisubstituted benzimidazole class of thrombin inhibitors, such as dabigatran. Molecular docking models predicted the binding of SAB to the thrombin active site.

Conclusion

Our data established SAB as the first herb-derived direct thrombin catalytic site inhibitor, suppressing thrombosis through both thrombin-dependent and thrombin-independent pathways. Purified SAB may be a cost-effective agent for treating arterial and deep vein thrombosis.

Enhanced coagulation cascade activation and styptic effects of Zn@SiO2 nanocomposite

Humans often have bleeding, which exerts substantial selective pressure on the coagulation system to optimize hemostasis in a variety of situations. Uncontrolled hemorrhage due to severe trauma leads to morbidity and mortality. Although nonbiological surfaces such as silicates can activate coagulation factor XII (FXII), the presence of Zn (Zinc) in the material stimulates and activates the various steps in the coagulation cascade. This results in blood clotting. The Zn@SiO2 nanocomposite has an excellent hemostatic property that establishes hemostasis by activating the factors responsible for the formation of a stable clot called fibrin mesh. This can be used as a hemostatic agent during surgeries and in any other trauma condition related to bleeding. Zn@SiO2 was synthesized and characterized with XRD, FTIR and HRTEM. It is analyzed for its RBC (Red Blood Corpuscles) aggregation and Platelet adhesion ability, fibrin formation, thrombus formation and prothrombin time (PT), Activated Partial Thromboplastin Time (aPTT), D-dimer for its ability to activate the coagulation cascade to achieve stable clotting.

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

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

Outcomes of heparinized adult veno-arterial extracorporeal membrane oxygenation patients managed with low and high activated partial thromboplastin time targets: A systematic review and meta-analysis

INTRODUCTION

There are no randomized controlled trials comparing low and high activated partial thromboplastin time (aPTT) targets in heparinized adult veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) patients. Our systematic review and meta-analysis summarized complication rates in adult VA ECMO patients treated with low and high aPTT targets.

METHODS

Studies published from January 2000 to May 2022 were identified using Pubmed, Embase, Cochrane Library, and LILACS (Latin American and Caribbean Health Sciences Literature). Studies were included if aPTT was primarily used to guide heparin anticoagulation. For the low aPTT group, we included studies where aPTT goal was ≤60 seconds and for the high aPTT group, we included studies where aPTT goal was ≥60 seconds. Proportional meta-analysis with a random effects model was used to calculate pooled complication rates for patients in the two aPTT groups.

RESULTS

Twelve studies met inclusion criteria (5 in the low aPTT group and 7 in the high aPTT group). The pooled bleeding complication incidence for low aPTT studies was 53.6% (95% CI = 37.4%-69.4%, I2 = 60.8%) and for high aPTT studies was 43.8% (95% CI = 21.7%-67.1%, I2 = 91.8%). No studies in the low aPTT group reported overall thrombosis incidence, while three studies in the high aPTT group reported overall thrombosis incidence. The pooled thrombosis incidence for high aPTT studies was 16.1% (95% CI = 9.0%-24.5%, I2 = 13.1%).

CONCLUSIONS

Adult ECMO patients managed with low and high aPTT goals appeared to have similar bleeding and other complication rates further highlighting the need for a randomized controlled trial.

Active monitoring of long-eared owl (Asio otus) nestlings reveals widespread exposure to anticoagulant rodenticides across different agricultural landscapes

The widespread use of anticoagulant rodenticides (ARs) poses a worldwide threat to farmland wildlife. These compounds accumulate in tissues of both target and non-target species, potentially endangering both direct consumers and their predators. However, investigations on ARs in blood of free-ranging predatory birds are rare. Here, the long-eared owl (Asio otus) has been used as a model predator to assess AR exposure in different agricultural landscapes from a Mediterranean semiarid region. A total of 69 owlets from 38 nests were blood-sampled over 2021 and 2022, aiming to detect AR residues and explore factors that determine their exposure, such as land uses. In addition, prothrombin time (PT) test was conducted to assess potential effects of AR contamination. Overall, nearly all the samples (98.6 %) tested positive for at least one compound and multiple ARs were found in most of the individuals (82.6 %). Among the ARs detected, flocoumafen was the most common compound (88.4 % of the samples). AR total concentration (ΣARs) in blood ranged from 0.06 to 34.18 ng mL-1, detecting the highest levels in the most intensively cultivated area. The analysis of owl pellets from 19 breeding territories showed relevant among-site differences in the contribution of rodents and birds into the diet of long-eared owls, supporting its high dietary plasticity and indicating AR presence at multiple trophic levels. Moreover, a positive and significant correlation was found between ΣARs and PT (Rho = 0.547, p < 0.001), which demonstrates the direct effect of ARs on free-living nestlings. Our results provide a preliminary overview of AR exposure in a little-studied owl species inhabiting agricultural and rural landscapes. Despite the low detected levels, these findings indicate widespread exposure -often to multiple compounds- from early life stages, which raises concern and draws attention to an ongoing and unresolved contamination issue.

[Update on point-of-care-based coagulation treatment : Systems, reagents, device-specific treatment algorithms]

Viscoelastic test (VET) procedures suitable for point-of-care (POC) testing are in widespread clinical use. Due to the expanded range of available devices and in particular due to the development of new test approaches and methods, the authors believe that an update of the current treatment algorithms is necessary. The aim of this article is to provide an overview of the currently available VET devices and the associated reagents. In addition, two treatment algorithms for the VET devices most commonly used in German-speaking countries are presented.

The use of NexoBrid™ enzymatic debridement and coagulation abnormalities

OBJECTIVES

Current evidence on how the use of bromelain-based enzymatic debridement techniques (NexoBrid™) affect patient coagulation is limited. A single patient case report [1] suggests that a patient with 15% total body surface area (TBSA) burn developed decreased coagulation activity following debridement with NexoBrid™ enzymatic debridement (ED). Regional Burns Centres in the United Kingdom may be reluctant to use ED, particularly in larger burns, citing concerns regarding coagulation. At our centre we have routinely used ED on deep partial thickness burns since 2017 including on patients with burns over 15% TBSA. This study aims to investigate whether there is a significant disruption in coagulation in patients undergoing ED with burns > 15% TBSA or admitted to intensive care compared to the standard of care (SOC) which is surgical debridement in theatre.

METHODS

This single-centre retrospective study includes all patients with a burn treated with ED at Pinderfields General Hospital Regional Burns Centre intensive care unit (ITU) from 2017 to 2020. Patients were matched to those treated with SOC at the same centre by age, % TBSA burn and presence of inhalational injury. These parameters correlate with the Baux score [9]. Percentage of burn debrided was matched as closely as possible, with coagulation profiles and platelet count taken the day before, the day of and three days following surgery.

RESULTS

Thirty-one patients were treated with ED in the intensive care unit between 2017 and 2020. Four patients were excluded due to insufficient records and one patient was anti-coagulated. Twenty-six patients were included and matched as described above. Average age of patients receiving ED was 44 years, the same in the matched group. Average TBSA burn is 35.5% (35.8% in matched group). No statistically significant difference in coagulation was seen between patients undergoing ED compared to SOC when considering prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet count. Both groups slightly breached the upper limit of normal on day 2 post ED and SOC. There was a slight breach of the lower limit of the average platelet count on day 2 post-ED which was neither statistically nor clinically significant.

CONCLUSIONS

Large burns are associated with coagulation abnormalities, therefore isolating a single variable in this cohort is challenging. However, this study found no significant change following ED use when compared to SOC and therefore no convincing evidence that ED is associated with coagulation abnormalities. This study represents one of the largest focusing on coagulation abnormalities following the use of ED, as the current literature is limited. Our study suggests that concerns regarding coagulation abnormalities should not prevent patients with large, deep partial thickness burns or full thickness burns being treated with ED.

Thromboelastographic evaluation after cardiac surgery optimizes transfusion requirements in the intensive care unit: a single-center retrospective cohort study using an inverse probability weighting method

OBJECTIVE

There are no reports from Japan showing the effects of using the thromboelastography algorithm on transfusion requirements after Intensive Care Unit (ICU) admission, and post-implementation knowledge regarding the thromboelastography algorithm under the Japanese healthcare system is insufficient. Therefore, this study aimed to clarify the effect of the TEG6s thromboelastography algorithm on transfusion requirements for patients in the ICU after cardiac surgery.

METHODS

We retrospectively compared the requirements for blood transfusion up to 24 h after ICU admission using the thromboelastography algorithm (January 2021 to April 2022) (thromboelastography group; n = 201) and specialist consultation with surgeons and anesthesiologists (January 2018 to December 2020) (non-thromboelastography group; n = 494).

RESULTS

There were no significant between-group differences in terms of age, height, weight, body mass index, operative procedure, duration of surgery or cardiopulmonary bypass, body temperature, or urine volume during surgical intervention. Moreover, there was no significant between-group difference in the amount of drainage at 24 h after ICU admission. However, crystalloid and urine volumes were significantly higher in the thromboelastography group than in the non-thromboelastography group. Additionally, fresh-frozen plasma (FFP) transfusion volumes were significantly lower in the thromboelastography group. However, there were no significant between-group differences in red blood cell count or platelet transfusion volume. After variable adjustment, the amount of FFP used from the operating room to 24 h after ICU admission was significantly reduced in the thromboelastography group.

CONCLUSIONS

The thromboelastography algorithm optimized transfusion requirements at 24 h after admission to the ICU following cardiac surgery.

Long Non-Coding RNAs: Bridging Cancer-Associated Thrombosis and Clinical Outcome of Ovarian Cancer Patients

Ovarian cancer (OC) and venous thromboembolism (VTE) have a close relationship, in which tumour cells surpass the haemostatic system to drive cancer progression. Long non-coding RNAs (lncRNAs) have been implicated in VTE pathogenesis, yet their roles in cancer-associated thrombosis (CAT) and their prognostic value are unexplored. Understanding how these lncRNAs influence venous thrombogenesis and ovarian tumorigenesis may lead to the identification of valuable biomarkers for VTE and OC management. Thus, this study evaluated the impact of five lncRNAs, namely MALAT1, TUG1, NEAT1, XIST and MEG8, on a cohort of 40 OC patients. Patients who developed VTE after OC diagnosis had worse overall survival compared to their counterparts (log-rank test, p = 0.028). Elevated pre-chemotherapy MEG8 levels in peripheral blood cells (PBCs) predicted VTE after OC diagnosis (Mann-Whitney U test, p = 0.037; Χ2 test, p = 0.033). In opposition, its low levels were linked to a higher risk of OC progression (adjusted hazard ratio (aHR) = 3.00; p = 0.039). Furthermore, low pre-chemotherapy NEAT1 levels in PBCs were associated with a higher risk of death (aHR = 6.25; p = 0.008). As for the remaining lncRNAs, no significant association with VTE incidence, OC progression or related mortality was observed. Future investigation with external validation in larger cohorts is needed to dissect the implications of the evaluated lncRNAs in OC patients.

Point-of-care, goal-directed management of bleeding in trauma patients

PURPOSE OF REVIEW

The purpose of this review is to consider the clinical value of point-of-care (POC) testing in coagulopathic trauma patients with traumatic brain injury (TBI) and trauma-induced coagulopathy (TIC).

RECENT FINDINGS

Patients suffering from severe TBI or TIC are at risk of developing pronounced haemostatic disorders. Standard coagulation tests (SCTs) are insufficient to reflect the complexity of these coagulopathies. Recent evidence has shown that viscoelastic tests (VETs) identify haemostatic disorders more rapidly and in more detail than SCTs. Moreover, VET results can guide coagulation therapy, allowing individualised treatment, which decreases transfusion requirements. However, the impact of VET on mortality remains uncertain. In contrast to VETs, the clinical impact of POC platelet function testing is still unproven.

SUMMARY

POC SCTs are not able to characterise the complexity of trauma-associated coagulopathy. VETs provide a rapid estimation of underlying haemostatic disorders, thereby providing guidance for haemostatic therapy, which impacts allogenic blood transfusion requirements. The value of POC platelet function testing to identify platelet dysfunction and guide platelet transfusion is still uncertain.

Implementation of a Bleeding Risk Screening Tool and Hematology Referral Process Prior to Pediatric Endoscopy

OBJECTIVES

Gastrointestinal (GI) endoscopic procedures are considered low risk with an overall bleeding risk for upper and lower endoscopies of 0.11%. However, a certain population of patients may have a higher risk for bleeding, and there is not a standardized process for screening patients to determine who these patients are.

METHODS

At Children's Wisconsin, our gastroenterology and hematology divisions adapted an abbreviated version of a validated, history-based bleeding risk screening tool and implemented a hematology referral process to identify those at risk for bleeding prior to their first endoscopy. Provider compliance with the bleeding screen, referral to hematology, time to be seen in hematology clinic, new diagnoses of bleeding disorders, and bleeding complications were assessed from 2019 to 2021 across 3 phases.

RESULTS

Provider compliance with the bleeding screen improved throughout our study from 48% (120/251) to 75% (189/253). For those who screened positive, compliance with referral to hematology ranged from 38% to 74% across our phases. The overall time to be seen by hematology decreased from 30 days to 7.5 days. Eighteen patients ultimately screened positive and were seen in hematology clinic, of whom 22% (4/18) were diagnosed with a new bleeding disorder. No bleeding complications were seen in our study population.

CONCLUSIONS

Our quality improvement project provided a standardized screening tool to assess preoperative bleeding risk and reinforced the value of a history-based screening tool. This modified screening tool identified those with an undiagnosed bleeding disorder and preventative measures were undertaken to prevent procedural bleeding complications.

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.

Activated partial thromboplastin time as a potential biomarker for the diagnosis of tuberculous pleural effusion

BACKGROUND

The aim of this study was to explore the difference in activated partial thromboplastin time (APTT) levels in patients with tuberculous and non-tuberculous pleural effusion (TPE and non-TPE) and its possible mechanism to provide a new direction for the diagnosis of pleural effusion (PE).

METHODS

A total of 61 patients diagnosed with tuberculous pleurisy with pleural effusion at Shunde Hospital of Southern Medical University from July 2013 to September 2020 were selected as the observation group (tuberculosis group). Another 89 patients (45 with malignant pleural effusion (MPE) and 44 with parapneumonic pleural effusion (PPE) composed the control group. The adenosine deaminase (ADA) level in pleural fluid and plasma APTT level were measured in the two groups.

RESULTS

The levels of APTT and ADA in the TPE group were significantly higher than the control group, and were 40.03 (37.00, 42.60) (s) and 55.00 (47.00, 69.25) (U/L) for TPE, 29.50 (25.45, 34.20) (s) and 11.90 (9.15, 19.05) (U/L) for malignant pleural effusion (MPE) and 31.35 (27.43, 35.76) (s) and 15.15 (7.40, 35.00) (U/L) for parapneumonic pleural effusion (PPE), respectively.

CONCLUSIONS

The level of plasma APTT has certain significance in differentiating tuberculous pleural effusion from nontuberculous pleural effusion.

Preoperative coagulation screening tests in pediatric patients: Clinical relevance and hemorrhagic outcomes of abnormal results

PURPOSE

Coagulation screening tests in children are still frequently performed in many countries to evaluate bleeding risk. The aim of this study was to assess the management of unexpected prolongations of the activated partial thromboplastin time (APTT) and prothrombine time (PT) in children prior to elective surgery, and the perioperative hemorrhagic outcomes.

METHODS

Children with prolonged APTT and/or PT who attended a preoperative anesthesia consultation from January 2013 to December 2018 were included. Patients were grouped according to whether they were referred to a Hematologist or were scheduled to undergo surgery without further investigation. The primary endpoint was to compare perioperative bleeding complications.

RESULTS

1835 children were screened for eligibility. 102 presented abnormal results (5.6%). Of them, 45% were referred to a Hematologist. Significant bleeding disorders were associated with a positive bleeding history, odds ratio of 51 (95% CI 4.8-538.5, P=.0011). No difference in perioperative hemorrhagic outcomes were found between the groups. An additional cost of 181 euros per patient and a preoperative median delay of 43 days was observed in patients referred to Hematology.

CONCLUSIONS

Our results suggest that hematology referral has limited value in asymptomatic children with a prolonged APTT and/or PT. Hemorrhagic complications were similar among patients referred and not referred to Hematology. A positive personal or family bleeding history can help identify patients with a higher bleeding risk, thus it should guide the need for coagulation testing and hematology referral. Further efforts should be made to standardize preoperative bleeding assessments tools in children.

Prothrombin Time and Coagulation Factor IX as Hemostatic Risk Markers for Legg- Calvé-Perthes Disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is a pediatric disorder that occurs due to the avascular necrosis of the femoral head and affects the range of motion of the hip in various degrees. Its etiology is still unknown, although it has been associated with coagulation abnormalities, however, the lack of reproducibility in the results in various studies has created a controversy as to whether hemostasis disorders are related to LCPD. On the other hand, there is little information on laboratory studies that could facilitate the diagnosis and treatment of LCPD.

METHODS

Blood and plasma samples were tested from 25 patients with LCPD and 50 healthy controls, matched by sex and age. Cellular markers were evaluated through complete blood count, as well as coagulation times, coagulation factors activity, antithrombotic proteins, and homocysteine concentration.

RESULTS

After assessing activity value frequencies in each group, the results showed more significant activity in some of the biological risk markers of thrombophilia, presenting a substantial difference in prothrombin time↘, FV↗, FVIII↗, FIX↗, and Hcy↗. These values imply that there may be hypercoagulable states in patients, which can cause thrombotic events.

CONCLUSIONS

Diminished prothrombin time and increase in FV activity, FVIII, FIX, and Hcy concentration support the hypothesis that microthrombi formation in small-caliber vessels could be causing avascularity and femoral necrosis, which are traits of LCPD. In addition, based on our results, we believe that the laboratory studies carried out are very useful in the diagnosis and treatment of LCPD.

Haemostasis and Inflammatory Parameters as Potential Diagnostic Biomarkers for VTE in Trauma-Immobilized Patients

Venous thromboembolism (VTE), which encompasses deep venous thrombosis (DVT) and pulmonary embolism (PE), is a major public health concern due to its high incidences of morbidity and mortality. Patients who have experienced trauma with prolonged immobilization are at an increased risk of developing VTE. Plasma D-dimer levels have been known to be elevated in trauma patients, and they were closely correlated with the number of fractures. In other words, plasma D-dimer levels cannot be used as the only indicator of VTE in trauma cases. Given the limitations, further study is needed to explore other potential biomarkers for diagnosing VTE. To date, various established and novel VTE biomarkers have been studied in terms of their potential for predicting VTE, diagnostic performance, and improving clinical therapy for VTE. Therefore, this review aims to provide information regarding classic and essential haemostasis (including prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, fibrinogen, thrombin generation, protein C, protein S, antithrombin, tissue factor pathway inhibitor, and platelet count) and inflammatory biomarkers (C-reactive protein, erythrocyte sedimentation rate, and soluble P-selectin) as potential diagnostic biomarkers that can predict the risk of VTE development among trauma patients with prolonged immobilization. Thus, further advancement in risk stratification using these biomarkers would allow for a better diagnosis of patients with VTE, especially in areas with limited resources.

Microplastic Effects on Thrombin-Fibrinogen Clotting Dynamics Measured via Turbidity and Thromboelastography

Micro/nanoplastics, whether manufactured or resulting from environmental degradation, can enter the body through ingestion, inhalation, or dermal pathways. Previous research has found that nanoplastics with diameters of ≤100 nm can translocate into the circulatory system in a dose-dependent manner and potentially impact thrombosis and hemostasis. To investigate the direct effects of microplastics on fibrin clot formation, a simplified ex vivo human thrombin/fibrinogen clot model was utilized. The 100 nm polystyrene particles (non-functionalized [nPS] and aminated [aPS]) were preincubated (0-200 µg/mL) with either thrombin or fibrinogen, and fibrin clot formation was characterized via turbidity and thromboelastography (TEG). When the particles were preincubated with fibrinogen, little effect was observed for aPS or nPS on turbidity or TEG up through 100 µg/mL. TEG results demonstrated a significant impact on clot formation rate and strength, in the case of nPS preincubated with thrombin exhibiting a significant dose-dependent inhibitory effect. In conclusion, the presence of microplastics can have inhibitory effects on fibrin clot formation that are dependent upon both particle surface charge and concentration. Negatively charged nPS exhibited the most significant impacts to clot strength, turbidity, and rate of fibrin formation when first incubated with thrombin, with its impact being greatly diminished when preincubated with fibrinogen in this simplified fibrin clot model.

Development of a paper-based lateral flow prothrombin assay

Disorders of haemostasis result in both excessive bleeding and clotting and are a major global cause of morbidity and mortality, particularly in the developing world. A small number of simple tests can be used to screen and monitor for such dysfunctions, one of which is the prothrombin time (PT) test and associated International Normalisation Ratio (INR). PT/INR is routine in hospital laboratories in developed countries, and can also be performed using point-of-care instruments. However, neither of these approaches is appropriate in low-resource settings. Significant interest has grown in paper-based devices to form the basis of simple and low-cost assays that may have the potential for application in such environments. This study describes the development of a simple, low-cost, paper-based lateral flow prothrombin assay. The assay employed wax printing on chromatography paper to define test channels, with deposition of thromboplastin reagent and calcium chloride onto the resulting strips. These were placed in a test housing and measurement of the flow rates of deposited plasma samples were performed in triplicate. The flow dynamics of the assay was optimised according to the type of paper substrate used, the nature and quantity of the thromboplastin reagent, the amount of calcium chloride required, and the volume of sample employed. An optimised assay configuration demonstrated a dynamic range of 6 mm between normal and factor-deficient plasmas. The assay showed good correlation with laboratory-based PT assay (Yumizen G200) in artificial plasmas in the 9.8 to 36 s range (r² = 0.8112). The assay also demonstrated good dynamic range and correlation in patient plasma samples in comparison with hospital PT, with a range of 9.8 to 45 s (r² = 0.7209).

Evaluating for Suspected Child Abuse: Conditions That Predispose to Bleeding

Child abuse might be suspected when children present with cutaneous bruising, intracranial hemorrhage, or other manifestations of bleeding. In these cases, it is necessary to consider medical conditions that predispose to easy bleeding or bruising. When evaluating for the possibility of bleeding disorders and other conditions that predispose to hemorrhage, it is important for pediatricians to consider the child's presenting history, medical history, and physical examination findings before initiating a laboratory investigation. Many medical conditions can predispose to easy bleeding. Before ordering laboratory tests for a disease, it is useful to understand the biochemical basis and clinical presentation of the disorder, condition prevalence, and test characteristics. This technical report reviews the major medical conditions that predispose to bruising or bleeding and should be considered when evaluating for abusive injury.

Optimization of human platelet lysate production and pathogen reduction in a public blood transfusion center

BACKGROUND

Human platelet lysate (HPL) has been proposed as a safe and efficient xeno-free alternative to fetal bovine serum (FBS) for large-scale culturing of cell-based medicinal products. However, the use of blood derivatives poses a potential risk of pathogen transmission. To mitigate this risk, different pathogen reduction treatment (PRT) practices can be applied on starting materials or on final products, but these methods might modify the final composition and the quality of the products.

STUDY DESIGN AND METHODS

We evaluated the impact of applying a PRT based on riboflavin and ultraviolet irradiation on the raw materials used to manufacture an improved Good Manufacturing Practices (GMP)-grade HPL product in a public blood center. Growth promotion and the levels of growth factors and proteins were compared between an inactivated product (HPL4-i) and a non-inactivated product (HPL4). Stability studies were performed at 4°C, -20°C, and -80°C.

RESULTS

The application of a PRT on the starting materials significantly altered the protein composition of HPL4-i as compared with HPL4. Despite this, the growth promoting rates were unaffected when compared with FBS used as a control. While all products were stable at -20°C and -80°C for 24 months, a significant decrease in the activity of HPL4-i was observed when stored at 4°C.

CONCLUSION

Our results show that the application of a PRT based on riboflavin and ultraviolet light on starting materials used in the manufacture of HPL modifies the final composition of the product, yet its cell growth promoting activity is maintained at levels similar to those of non-inactivated products.

Post-operative haemorrhage secondary to cinnamon use. A case report

Introduction

Herbal medicine plays a significant role in modern medicine. The difficulty in integrating the two, lies in the unknown quantities of active ingredients in herbal remedies. This proved true in this clinical scenario. The quantity of coumarin, in the form of cinnamon ingested by this patient over ten months is unknown. The only quantifiable measure was the derangement in his extrinsic coagulation pathway.

Presentation of case

A 49-year-old male with a history of celiac disease presented with haematochezia secondary to a malignant adenocarcinoma of the transverse colon. The patient underwent a laparoscopic subtotal colectomy and on the second post-operative day, he was noted to have peritonitis and a positive Fox sign. Diagnostic laparoscopy confirmed intraabdominal bleeding. Over the next four days, the patient's haemoglobin plummeted from 17.4 g/dL to 8.0 g/dL. Investigations revealed an INR of 1.59, which led to further questioning into dietary practices. The patient admitted he had been taking Ceylon cinnamon one tablespoon daily for ten months in the period leading up to surgery.

Discussion

Coumarin is a chemical compound readily available in food items such as cinnamon. Coumarin possesses the ability to inhibit vitamin K epoxide reductase complex 1 which is responsible for the recycling of vitamin K. This impedes the gamma-carboxylation of coagulation factors II, VII, IX, X. Vitamin K antagonism can manifest as a prolonged INR and normal activated partial thromboplastin time.

Conclusion

Bleeding diathesis secondary to dietary coumarin is a rare but dangerous phenomenon that emphasizes the need for a thorough interrogation into a patient's dietary history.

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Cinnamon is a coumarin that can cause coagulopathy when used in excess.

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Dietary coumarin is a recognized cause of postoperative haemorrhage.

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Reactive haemorrhage can cause significant morbidity.

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Coagulopathy due to dietary coumarin can be rectified with fresh frozen plasma.

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A thorough dietary history is imperative in safe patient care.

[Coagulation diagnostics in the clinical routine-Part 1 : Evaluation of the risk of bleeding before surgery, interventions and diagnostics in bleeding diathesis]

This article on coagulation diagnostics is published in two parts covering five common clinical scenarios for coagulation diagnostics. Part 1 deals with the diagnostics prior to invasive interventions and coagulation diagnostics to clarify a tendency to bleeding. The global parameters Quick and activated partial thromboplastin time are established for monitoring certain anticoagulants; however, they are not predictive with respect to the risk of bleeding prior to elective invasive interventions. In this context, disorders of primary hemostasis are frequent, which are insufficiently detected by the global parameters. Most clinical bleeding tendencies are due to acquired causes. These include anticoagulants and diseases which can be accompanied by tendency to bleeding. For coagulation tests preanalytical issues are essential in order to avoid false results. The interpretation should always be made in the context of the current physiological state.

Near-Infrared Light-Activatable Spherical Nucleic Acids for Conditional Control of Protein Activity

Optical control of protein activity represents a promising strategy for precise modulation of biological processes. We report rationally designed, aptamer-based spherical nucleic acids (SNAs) capable of noninvasive and programmable regulation of target protein activity by deep-tissue-penetrable near-infrared (NIR) light. The photoresponsive SNAs are constructed by integrating activatable aptamer modules onto the surface of upconversion nanoparticles. The SNAs remain inert but can be remotely reverted by NIR light irradiation to capture the target protein and thus function as an enzyme inhibitor, while introduction of antidote DNA could further reverse their inhibition functions. Furthermore, we demonstrate the potential of the SNAs as controllable anticoagulants for the NIR light-triggered regulation of thrombin function. Ultimately, the availability of diverse aptamers would allow the design to regulate the activities of various proteins in a programmable manner.

Determining an approximate minimum toxic dosage of diphacinone in horses and corresponding serum, blood, and liver diphacinone concentrations: a pilot study

Poisoning of nontarget species is a major concern with the use of anticoagulant rodenticides (ARs). At postmortem examination, differentiating toxicosis from incidental exposure is sometimes difficult. Clotting profiles cannot be performed on postmortem samples, and clinically significant serum, blood, and liver AR concentrations are not well-established in most species. We chose diphacinone for our study because, at the time, it was the publicly available AR most commonly detected in samples analyzed at the University of Kentucky Veterinary Diagnostic Laboratory. We determined an approximate minimum toxic dosage (MTD) of oral diphacinone in 3 horses and measured corresponding serum, blood, and liver diphacinone concentrations. Diphacinone was administered orally to healthy horses. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and serum and blood diphacinone concentrations were measured daily. At the study endpoint, the horses were euthanized, and diphacinone concentration was measured in each liver lobe. The horse that received 0.2 mg/kg diphacinone developed prolonged (>1.5× baseline) PT and aPTT; the horse that received 0.1 mg/kg did not. This suggests an approximate oral MTD in horses of 0.2 mg/kg diphacinone. Median liver diphacinone concentration at this dosage was 1,780 (range: 1,590–2,000) ppb wet weight. Marginal (model-adjusted) mean diphacinone concentrations of liver lobes were not significantly different from one another ( p = NS). Diphacinone was present in similar concentrations in both serum and blood at each time after administration, indicating that both matrices are suitable for detection of diphacinone exposure in horses.

The Composition and Physical Properties of Clots in COVID-19 Pathology

Hemostasis is a finely tuned process of which dysregulation can lead either to bleeding or thrombotic complications. The latter is often caused by the hypercoagulable state as it is also seen in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, i.e., in COVID-19 patients. COVID-19 patients requiring hospitalization often suffer from thrombotic events that could not be predicted using routine coagulation assays. Recently, several studies have reported ROtational ThromboElastoMetry (ROTEM) as a promising tool to predict outcomes in COVID-19 patients. In this review we give an overview of ROTEM with a particular focus on the interpretation of the symmetrical clot formation curve in relation to coagulopathy in COVID-19 patients. Furthermore, we have introduced new parameters that might help to better distinguish between COVID-19 patients and outcomes.

Assessing Coagulation Parameters in Healthy Asian Elephants (Elephas maximus) from European and Thai Populations

The Asian elephant population is continuously declining due to several extrinsic reasons in their range countries, but also due to diseases in captive populations worldwide. One of these diseases, the elephant endotheliotropic herpesvirus (EEHV) hemorrhagic disease, is very impactful because it particularly affects Asian elephant calves. It is commonly fatal and presents as an acute and generalized hemorrhagic syndrome. Therefore, having reference values of coagulation parameters, and obtaining such values for diseased animals in a very short time, is of great importance. We analyzed prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen concentrations using a portable and fast point-of-care analyzer (VetScan Pro) in 127 Asian elephants from Thai camps and European captive herds. We found significantly different PT and aPTT coagulation times between elephants from the two regions, as well as clear differences in fibrinogen concentration. Nevertheless, these alterations were not expected to have biological or clinical implications. We have also sequenced the coagulation factor VII gene of 141 animals to assess the presence of a previously reported hereditary coagulation disorder in Asian elephants and to investigate the presence of other mutations. We did not find the previously reported mutation in our study population. Instead, we discovered the presence of several new single nucleotide polymorphisms, two of them being considered as deleterious by effect prediction software.

Tannins as Hemostasis Modulators

The hemostasis system is often affected by complications associated with cardiovascular diseases, which results in thromboembolic events. Compounds of plant origin and plant extracts are considered as a promising source of substances that could modulate the functioning of the hemostasis system and thus reduce the risk of thromboembolism. Among them, tannins, which are plant-origin compounds with potential effects in hemostasis, deserve a special mention. This paper describes the hemostasis-modifying ability of three groups of tannins, namely ellagitannins, gallotannins, and procyanidins. The review highlights the desirable as well as undesirable influence of tannins on specific components of hemostasis, namely platelets, coagulation system, fibrinolysis system, and endothelium, and the multidirectional effect of these compounds on the thrombotic process. Studies performed under normal and pathological conditions such as diabetes or hypercoagulation are described, and the pathophysiology-dependent action of tannins is also highlighted. Most of the studies presented in the paper were performed in vitro, and due to the low bioavailability of tannins more studies should be conducted in the future to understand their actual activity in vivo.

Remodeling of Structurally Reinforced (TPU+PCL/PCL)-Hep Electro-spun Small Diameter Bilayer Vascular Grafts Interposed in Rat Ab-dominal Aorta

As the thermoplastic polyurethane (TPU) elastomer possesses good biocompatibility and mechanical properties similar to native vascular tissues as well, it is intended to co-electrospin with poly(ε-caprolactone) (PCL) onto the outer...

A novel anticoagulant peptide discovered from Crassostrea gigas by combining bioinformatics with the enzymolysis strategy: inhibitory kinetics and mechanisms

A novel anticoagulant peptide (IEELEEELEAER) derived from oyster (Crassostrea gigas) was discovered by combining the emerging bioinformatics with the classical enzymolysis approach. The anticoagulant peptide drastically reduced the extrinsic clotting activity (49% residual PT activity) and impaired the intrinsic clotting activity (77% residual PT activity). Consistent with the clotting data, the thrombin peak height reduced to 88.7 from 123.4 nM, and the thrombin generation time delayed to 5.32 from 4.42 min when an extrinsic trigger was applied. The inhibitory kinetics of FXIa, FIXa, FXa, FIIa, and APC in a purified component system rationally explained the reduction of the extrinsic clotting activity and impairment of thrombin generation. Besides the inhibition of FXa and FIIa activity, the activation processes of FX and FII by an intrinsic/extrinsic tenase complex and prothrombinase were also damaged. The anticoagulant activity in the plasma system was the result of comprehensive inhibition of various factors. The research provided a frame for anticoagulant evaluation and inhibitory mechanism of bioactive peptides from food products.

Point of care whole blood microfluidics for detecting and managing thrombotic and bleeding risks

Point-of-care diagnostics of platelet and coagulation function present demanding challenges. Current clinical diagnostics often use centrifuged plasmas or platelets and frozen plasma standards, recombinant protein standards, or even venoms. Almost all commercialized tests of blood do not recreate the in vivo hemodynamics where platelets accumulate to high densities and thrombin is generated from a procoagulant surface. Despite numerous drugs that target platelets, insufficient coagulation, or excess coagulation, POC blood testing is essentially limited to viscoelastic methods that provide a clotting time, clot strength, and clot lysis, while used mostly in trauma centers with specialized capabilities. Microfluidics now allows small volumes of whole blood (<1 mL) to be tested under venous or arterial shear rates with multi-color readouts to follow platelet function, thrombin generation, fibrin production, and clot stability. Injection molded chips containing pre-patterned fibrillar collagen and lipidated tissue factor can be stored dry for 6 months at 4C, thus allowing rapid blood testing on single-use disposable chips. Using only a small imaging microscope and micropump, these microfluidic devices can detect platelet inhibitors, direct oral anticoagulants (DOACs) and their reversal agents. POC microfluidics are ideal for neonatal surgical applications that involve small blood samples, rapid DOAC testing in stroke or bleeding or emergency surgery situations with patients presenting high risk cofactors for either bleeding or thrombosis.

Effect of urban air pollution on CRP and coagulation: a study on inpatients with acute exacerbation of chronic obstructive pulmonary disease

PURPOSE

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is an important event in the course of chronic obstructive pulmonary disease that negatively affects patients' quality of life and leads to higher socioeconomic costs. While previous studies have demonstrated a significant association between urban air pollution and hospitalization for AECOPD, there is a lack of research on the impact of particulate matter (PM) on inflammation and coagulation in AECOPD inpatients. Therefore, this study investigated the association of changes in coagulation function and C-reactive protein (CRP) with PM levels in the days preceding hospitalization.

PATIENTS AND METHODS

We reviewed the medical records of AECOPD patients admitted to Putuo Hospital, Shanghai University of Traditional Chinese Medicine, between March 2017 and September 2019. We analyzed the association of coagulation function and CRP level in AECOPD patients with PM levels in the days before hospitalization. Multivariate unconditional logistic regression analyses were used to evaluate the adjusted odds ratio (OR) and 95% confidence interval (CI) for the association of CRP data with hospitalization day. Kruskal-Wallis tests were used to evaluate mean aerodynamic diameter of ≥ 2.5 μm (PM2.5) exposure on the day before hospitalization; we assessed its association with changes in prothrombin time (PT) in AECOPD inpatients with different Global Initiative for Chronic Obstructive Lung Disease (GOLD) classes.

RESULTS

The peripheral blood PT of AECOPD patients with PM2.5 ≥ 25 mg/L on the day before hospitalization were lower than those of patients with PM2.5 < 25 mg/L (t = 2.052, p = 0.041). Patients with severe GOLD class exposed to greater than 25 mg/L of PM2.5on the day before hospitalization showed significant differences in PT (F = 9.683, p = 0.008). Peripheral blood CRP levels of AECOPD patients exposed to PM2.5 ≥ 25 mg/L and PM10 ≥ 50 mg/L on the day before hospitalization were higher than those of patients exposed to PM2.5 < 25 mg/L and PM10 < 50 mg/L (t = 2.008, p = 0.046; t = 2.637, p = 0.009). Exposure to < 25 mg/L of PM2.5 on the day before hospitalization was significantly associated with CRP levels (adjusted OR 1.91; 95% CI 1.101, 3.315; p = 0.024).

CONCLUSION

Exposure of patients with AECOPD to high PM levels on the day before hospitalization was associated with an increased CRP level and shortened PT. Moreover, PM2.5 had a greater effect on CRP level and PT than mean aerodynamic diameter of ≥ 10 μm (PM10). AECOPD patients with severe GOLD class were more sensitive to PM2.5-induced shortening of PT than those with other GOLD classes.

Perioperative Coagulation Monitoring

The main goal of perioperative coagulation monitoring is to improve safety of patients undergoing surgical procedures. Various conditions can affect the coagulation system during surgery and bleeding. The value of traditional standard coagulation tests is limited in detecting hemostatic dysfunctions and they are particularly ineffective in diagnosing hyperfibrinolysis. This article reports on key issues and pathophysiologic changes that affect the hemostatic system in the perioperative setting. Values of preoperative coagulation tests are discussed and the basic principles for point-of-care coagulation devices, including platelet analyzers and their clinical use, are evaluated.

Facile and green approach towards biomass-derived hydrogel powders with hierarchical micro-nanostructures for ultrafast hemostasis

Although a series of biomass-derived hemostats has been developed, the desire for green-prepared hemostatic materials with biosafety has not decreased. Herein, we constructed porous carboxymethyl chitosan/sodium alginate/Ca(OH)₂ powders (PCSCPs) with suitable adaptability for instant control of irregular hemorrhage via a facile and green approach. By one-pot chemical crosslinking of carboxymethyl chitosan and sodium alginate, hydrogels were formed and immediately ionically cross-linked along with the generation of Ca(OH)₂ to prepare PCSCPs. As hydrogel powders, PCSCPs with abundant hydrophilic carboxymethyl groups and porous hierarchically micro-nanostructures displayed a high water absorption ratio of over 1600%. The PCSCPs were confirmed with favorable hemocompatibility, non-cytotoxic effects and excellent degradability. Hemostasis assays in vitro showed that PCSCPs possessed an outstanding property of platelet activation and red blood cell aggregation. The PCSCPs effectively shortened the hemostatic time and blood loss to ca. 50% in rodent bleeding models compared with medical gauze and commercial chitosan-based hemostats. Furthermore, a mouse subcutaneous implantation model demonstrated an ignorable inflammation response and potential tissue repair capability of PCSCPs. It's believed that green-prepared and biomass-derived PCSCPs are feasible biomedical hemostatic materials in view of engineering and provide a promising platform to design hemostats in prehospital management and clinical settings.

Thermally driven formation of polyphenolic carbonized nanogels with high anticoagulant activity from polysaccharides

We have demonstrated that alginate with negligible anticoagulant activity can be converted into carbonized nanogels with potent anticoagulant activity through a solid-state heating process. The conversion of alginate into graphene-like nanosheet (GNS)-embedded polyphenolic-alginate nanogels (GNS/Alg-NGs) has been carried out through condensation and carbonization processes. The GNS/Alg-NGs exhibit much stronger anticoagulant activity (>520-fold) compared to untreated alginate, mainly because their polyphenolic structures have a high binding affinity [dissociation constant (K_d) = 2.1 × 10^-10 M] toward thrombin. In addition, the thrombin clotting time delay caused by the GNS/Alg-NGs is 10-fold longer than that of natural polyphenolic compounds, such as quercetin, catechin, naringenin, caffeic acid, and ferulic acid. The thrombin- or kaolin-activated thromboelastography of whole-blood coagulation reveals that the GNS/Alg-NGs display a much stronger anticoagulant ability than that of untreated alginate and naturally sulfated polysaccharides (fucoidan). The GNS/Alg-NGs exhibit superior biocompatibility and anticoagulant activity, as observed with an in vivo rat model, revealing their potential as a blood thinner for the treatment of thrombotic disorders.

The influence of hydrogen ions on coagulation in traumatic brain injury, explored by molecular dynamics

Background: Patients in intensive care units with traumatic brain injuries (TBI) frequently present acid-base abnormalities and coagulability disorders, which complicate their condition.Objective: To identify protonation through in silico simulations of molecules involved in the process of coagulation in standard laboratory tests.Materials and methods: Ten patients with TBI were selected from the intensive care unit in addition to ten "healthy control subjects", and another nine patients as "disease control subjects"; the latter being a comparative group, corresponding to subjects with diabetes mellitus 2 (DM2). Fibrinogen, FVII, FVIII, FIX, FX, and D-dimer in the presence of acidification were evaluated in 20 healthy subjects in order to compare clinical results with molecular dynamics (MD), and to explain proton interactions and coagulation molecules.Results: The TBI group presented a slight, non-significant increase in D-dimer; but this was not present in "disease control subjects". Levels of fibrinogen, FVII, FIX, FX, and D-dimer were affected in the presence of acidification. We observed that various specific residues of coagulation factors "trap" ions.Conclusion: Protonation of tissue factor and factor VIIa may favor anticoagulant mechanisms, and protonation does not affect ligand binding sites of GPIIb/IIIa (PAC1) suggesting other causes for the low affinity to PAC1.

Massage of the Hepatoduodenal Ligament Recovers Portal Vein Flow Immediately After the Pringle Maneuver in Hepatectomy

BACKGROUND

The Pringle maneuver is often used in liver surgery to minimize bleeding during liver transection. Many authors have demonstrated that intermittent use of the Pringle maneuver is safe and effective when performed appropriately. However, some studies have reported that the Pringle maneuver is a significant risk factor for portal vein thrombosis. In this study, we evaluated the effectiveness of portal vein flow after the Pringle maneuver and the impact that massaging the hepatoduodenal ligament after the Pringle maneuver has on portal vein flow.

MATERIALS AND METHODS

Patients treated with the Pringle maneuver for hepatectomies performed to treat hepatic disease at our hospital between August 2014 and March 2019 were included in the study (N = 101). We divided these patients into two groups, a massage group and nonmassage group. We measured portal vein blood flow with ultrasonography before and after clamping of the hepatoduodenal ligament. We also evaluated laboratory data after the hepatectomy.

RESULTS

Portal vein flow was significantly lower after the Pringle maneuver than before clamping of the hepatoduodenal ligament. The portal vein flow after the Pringle maneuver was improved following massage of the hepatoduodenal ligament. After hepatectomy, serum prothrombin time was significantly higher and serum C-reactive protein was significantly lower in the massage group than in the nonmassage group.

CONCLUSION

Massaging the hepatoduodenal ligament after the Pringle maneuver is recommended in order to quickly recover portal vein flow during hepatectomy and to improve coagulability.

A DNA origami-based aptamer nanoarray for potent and reversible anticoagulation in hemodialysis

Effective and safe hemodialysis is essential for patients with acute kidney injury and chronic renal failures. However, the development of effective anticoagulant agents with safe antidotes for use during hemodialysis has proven challenging. Here, we describe DNA origami-based assemblies that enable the inhibition of thrombin activity and thrombus formation. Two different thrombin-binding aptamers decorated DNA origami initiates protein recognition and inhibition, exhibiting enhanced anticoagulation in human plasma, fresh whole blood and a murine model. In a dialyzer-containing extracorporeal circuit that mimicked clinical hemodialysis, the origami-based aptamer nanoarray effectively prevented thrombosis formation. Oligonucleotides containing sequences complementary to the thrombin-binding aptamers can efficiently neutralize the anticoagulant effects. The nanoarray is safe and immunologically inert in healthy mice, eliciting no detectable changes in liver and kidney functions or serum cytokine concentration. This DNA origami-based nanoagent represents a promising anticoagulant platform for the hemodialysis treatment of renal diseases.

Intracranial bleeding following soccer-related head trauma in a young student with occult factor VII deficiency

It is important to obtain coagulation tests to assess bleeding risk in trauma patients undergoing emergency surgery when a bleeding disorder may be obscured. Identifying specific clotting factor defects is critical in successful patient management.

Microphysiological systems for the modeling of wound healing and evaluation of pro-healing therapies

Wound healing is a multivariate process involving the coordinated response of numerous proteins and cell types. Accordingly, biomedical research has seen an increased adoption of the use of in vitro wound healing assays with complexity beyond that offered by traditional well-plate constructs. These microphysiological systems (MPS) seek to recapitulate one or more physiological features of the in vivo microenvironment, while retaining the analytical capacity of more reductionist assays. Design efforts to achieve relevant wound healing physiology include the use of dynamic perfusion over static culture, the incorporation of multiple cell types, the arrangement of cells in three dimensions, the addition of biomechanically and biochemically relevant hydrogels, and combinations thereof. This review provides a brief overview of the wound healing process and in vivo assays, and we critically review the current state of MPS and supporting technologies for modelling and studying wound healing. We distinguish between MPS that seek to inform a particular phase of wound healing, and constructs that have the potential to inform multiple phases of wound healing. This distinction is a product of whether analysis of a particular process is prioritized, or a particular physiology is prioritized, during design. Material selection is emphasized throughout, and relevant fabrication techniques discussed.

Hemostatic Changes in Patients with COVID-19: A Meta-Analysis with Meta-Regressions

BACKGROUND

Complications of coronavirus disease 2019 (COVID-19) include coagulopathy. We performed a meta-analysis on the association of COVID-19 severity with changes in hemostatic parameters.

METHODS

Data on prothrombin time (PT), activated partial thromboplastin time (aPTT), D-Dimer, platelets (PLT), or fibrinogen in severe versus mild COVID-19 patients, and/or in non-survivors to COVID-19 versus survivors were systematically searched. The standardized mean difference (SMD) was calculated.

RESULTS

Sixty studies comparing 5487 subjects with severe and 9670 subjects with mild COVID-19 documented higher PT (SMD: 0.41; 95%CI: 0.21, 0.60), D-Dimer (SMD: 0.67; 95%CI: 0.52, 0.82), and fibrinogen values (SMD: 1.84; 95%CI: 1.21, 2.47), with lower PLT count (SMD: -0.74; 95%CI: -1.01, -0.47) among severe patients. Twenty-five studies on 1511 COVID-19 non-survivors and 6287 survivors showed higher PT (SMD: 0.67; 95%CI: 0.39, 0.96) and D-Dimer values (SMD: 3.88; 95%CI: 2.70, 5.07), with lower PLT count (SMD: -0.60, 95%CI: -0.82, -0.38) among non-survivors. Regression models showed that C-reactive protein values were directly correlated with the difference in PT and fibrinogen.

CONCLUSIONS

Significant hemostatic changes are associated with COVID-19 severity. Considering the risk of fatal complications with residual chronic disability and poor long-term outcomes, further studies should investigate the prognostic role of hemostatic parameters in COVID-19 patients.

Preparation of multifunctional poly(l-lactic acid) film using heparin-mimetic polysaccharide multilayers: Hemocompatibility, cytotoxicity, antibacterial and drug loading/releasing properties

Poly(l-lactic acid) (PLLA) has been the most commonly used polymer for making bioresorbable vascular scaffolds (BVS). Despite owning remarkable properties, BVS made from PLLA are facing higher rates of early thrombosis compared with permanent metallic scaffolds. To solve this issue, we modified the PLLA film surface with heparin-mimetic polysaccharide multilayers consisting of sulfated Chinese yam polysaccharide (SCYP) and chitosan (CS) through layer-by-layer (LBL) assembly. The surface chemical compositions, morphologies and growth manner of SCYP/CS multilayers were investigated using X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and UV-vis spectroscopy. The relevant hemocompatibility results showed that multilayer-modified PLLA could effectively resist protein adsorption, suppress the platelet adhesion, prolong clotting time, prevent contact and complement activation as well as reduce hemolysis rate. Moreover, the multilayer-modified PLLA exhibited non-cytotoxicity, good antibacterial ability against E. coli and S. aureus, and drug loading/sustained releasing behavior. Overall, the multifunctional PLLA film with integrated properties of hemocompatibility, non-cytotoxicity, antibacterial and drug loading/releasing behavior could be successfully achieved by deposition of SCYP/CS multilayers, which will have potential application in blood-contacting biomedical materials.