Fibrinolytic Response Research Articles

Efficacy of tranexamic acid versus placebo in reducing blood loss during burn excisional surgery: a multi-center, double-blind, parallel, randomized placebo-controlled clinical trial (TRANEX)

BackgroundDespite an increase in knowledge, blood loss during burn excisional surgery remains a major challenge and is an independent predictor of mortality. During burn surgery, limited measures are available to control the bleeding. Increased fibrinolysis could be one of the contributing factors of blood loss during burn excisional surgery. Tranexamic acid inhibits the fibrinolytic response, and a small body of evidence shows positive effects of tranexamic acid on the volume of blood loss.MethodsThe main objectives of this study are twofold, (1) to investigate whether tranexamic acid reduces blood loss and (2) to investigate the changes in coagulation after burn trauma and during burn excisional surgery. This study is a multicenter double-blind randomized clinical trial in patients scheduled for burn excisional surgery within the Dutch burn centers. All adult patients scheduled for burn surgery with an expected blood loss of ≥ 250 are eligible for inclusion in this study. The study is powered on a blood loss reduction of 25% in the intervention group. In total, 95 subjects will be included. The intervention group will receive 1500 mg tranexamic acid versus placebo in the other group. Primary endpoint is reduction of blood loss. Secondary endpoints include occurrence of fibrinolysis during surgery, graft take of the split skin graft, and differences in coagulation and blood clot formation.DiscussionThis protocol of a randomized controlled trial aims to investigate the efficacy of tranexamic acid in reducing blood loss during burn excisional surgery. Furthermore, this study aims to clarify the coagulation status after burn trauma and during the surgical process.Trial registrationEudraCT: 2020-005405-10; ClinicalTrial.gov: NCT05507983 (retrospectively registered in August 2022, inclusion started in December 2021).

Development of a Methodology Based on Optical Interferometry for Measuring Fibrinolytic Activity.

Fibrinolytic activity assay is particularly important for the detection, diagnosis, and treatment of cardiovascular disease and the development of fibrinolytic drugs. A novel efficacious strategy for real-time and label-free dynamic detection of fibrinolytic activity based on ordered porous layer interferometry (OPLI) was developed. Fibrin or a mixture of fibrin and plasminogen (Plg) was loaded into the highly ordered silica colloidal crystal (SCC) film scaffold to construct a fibrinolytic response interference layer to measure fibrinolytic activity with different mechanisms of action. Fibrinolytic enzyme-triggered fibrinolysis led to the migration of interference fringes in the interferogram, which could be represented by optical thickness changes (ΔOT) tracked in real time by the OPLI system. The morphology and optical property of the fibrinolytic response interference layer were characterized, and the Plg content in the fibrinolytic response interference layer and experimental parameters of the system were optimized. The method showed adequate sensitivity for the fibrinolytic activity of lumbrokinase and streptokinase, with wide linear ranges of 12-6000 and 10-2000 U/mL, respectively. Compared with the traditional fibrin plate method, it has a lower detection limit and higher linearity. The whole kinetic process of fibrinolysis by these two fibrinolytic drug models was recorded in real time, and the Michaelis constant and apparent kinetic parameters were calculated. Importantly, some other blood proteins were less interfering with this system, and it showed reliability in fibrin activity detection in real whole blood samples. This study established a better and more targeted research method of in vitro fibrinolysis and provided dynamic monitoring data for the analysis of fibrinolytic activity of whole blood.

Neutrophil-mediated Inflammatory Plasminogen Degradation, Rather Than High Plasminogen-Activator Inhibitor-1, May Underly Failures and Inefficiencies of Intrapleural Fibrinolysis

Complex pleural space infections often require treatment with multiple doses of intrapleural tissue plasminogen activator (tPA) and deoxyribonuclease, with treatment failure frequently necessitating surgery. Pleural infections are rich in neutrophils, and neutrophil elastase degrades plasminogen, the target substrate of tPA, that is required to generate fibrinolysis. We hypothesized that pleural fluid from patients with pleural space infection would show high elastase activity, evidence of inflammatory plasminogen degradation, and low fibrinolytic potential in response to tPA that could be rescued with plasminogen supplementation. Does neutrophil elastase degradation of plasminogen contribute to intrapleural fibrinolytic failure? We obtained infected pleural fluid and circulating plasma from hospitalized adults (n= 10) with institutional review board approval from a randomized trial evaluating intrapleural fibrinolytics vssurgery for initial management of pleural space infection. Samples were collected before the intervention and on days 1, 2, and 3 after the intervention. Activity assays, enzyme-linked immunosorbent assays, and Western blot analysis were performed, and turbidimetric measurements of fibrinolysis were obtained from pleural fluid with and without exogenous plasminogen supplementation. Results are reported as median (interquartile range) or number (percentage) as appropriate, with an α value of .05. Pleural fluid elastase activity was more than fourfold higher (P= .02) and plasminogen antigen levels were more than threefold lower (P= .04) than their corresponding plasma values. Pleural fluid Western blot analysis demonstrated abundant plasminogen degradation fragments consistent with elastase degradation patterns. We found that plasminogen activator inhibitor 1 (PAI-1), the native tPA inhibitor, showed high antigen levels before the intervention, but the overwhelming majority of this PAI-1 (82%) was not active (P= .003), and all PAI-1 activity was lost by day 2 after the intervention in patients receiving intrapleural tPA and deoxyribonuclease. Finally, using turbidity clot lysis assays, we found that the pleural fluid of 9 of 10 patients was unable to generate a significant fibrinolytic response when challenged with tPA and that plasminogen supplementation rescued fibrinolysis in all patients. Our findings suggest that inflammatory plasminogen deficiency, not high PAI-1 activity, is a significant contributor to intrapleural fibrinolytic failure. ClinicalTrials.gov; No.: NCT03583931; URL: www. gov.

Variability of fibrinolytic activity in pregnant patients exposed to tissue plasminogen activator: an in vitro study utilizing rotational thromboelastometry

BackgroundThe investigation into the variability of fibrinolysis in obstetric patients is notably limited despite its relevance to postpartum hemorrhage. We investigate an in vitro model of fibrinolysis measured by rotational thromboelastrometry (ROTEM) in maternal blood samples with lysis stimulated by tissue plasminogen activator (tPA). MethodsWritten informed consent was obtained from 19 patients at term pregnancy during admission to the labor and delivery unit. Patients who were taking medication affecting coagulation were excluded. Tissue plasminogen activator was added to whole blood samples to a final concentration of 100 or 220 ng/mL prior to ROTEM testing. ResultsThe addition of tPA produced high intra-individual fibrinolytic variability for clot firmness and lysis parameters. Patients responded differently to each tPA dose ranging from clot lysis within the range of 0 ng/mL tPA group to complete clot lysis. The coefficient of variation (CV) values for the 220 ng/mL tPA group were: EXTEM MCF 0.510, EXTEM LI30 1.601, FIBTEM MCF 0.349, FIBTEM LI30 2.097. CV values for the 100 ng/mL tPA group were: EXTEM MCF 0.144, EXTEM LI30 1.038, FIBTEM MCF 0.096, FIBTEM LI30 1.238. ConclusionWe demonstrate a wide range of fibrinolytic response in the obstetric population to exogeneous tPA. We found subgroups of patients that were very responsive to tPA and insensitive to tPA. This study represents a preliminary exploration into classifying the obstetric fibrinolytic phenotypes. Further research will integrate relevant coagulation factors to establish a predictive model for testing susceptibility to lysis that can be applied at the point of care.

Exercise testing unmasks exaggerated blood pressure independent of fibrinolytic response in Black but not White postmenopausal females.

Exercise testing unmasks more exaggerated systolic blood pressure responses (SBP) in Black compared with White male adults. Such responses, if translatable to females, may detect racial disparities particularly relevant during menopause. Given the endothelial involvement in BP regulation and as a source of fibrinolytic markers, it follows that fibrinolytic and BP response to exercise could be linked. Thus, we examined BP and fibrinolytic responses to exercise testing in Black and White postmenopausal females. Postmenopausal females (Black = 40; White = 41; 51-70 yr) performed maximal treadmill exercise. BP and blood draws were conducted before and immediately after exercise. Plasma samples, using minimal stasis, were analyzed for tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) activity and antigen, respectively. Resting SBP and fibrinolytic potential were similar between races. Black females exhibited greater increases in SBP during exercise [change (d)=75, 95% CI: 64-86 mmHg, P < 0.001] than White females (d = 60, 95% CI: 48-71 mmHg, P < 0.001). Black compared with White females had smaller changes in tPA (d = 3.27, 95% CI: 2.28-4.27 IU/mL, P < 0.001 vs. d = 5.55, 95% CI: 4.58-6.53, P < 0.001) and PAI-1 (d = -2.89, 95% CI: -4.39 to -1.40 IU/mL, P < 0.001 vs. d = -5.08, 95% CI: -6.59 to -3.61, P < 0.001) activities after exercise. SBP exercise-induced changes were not associated with tPA (r = -0.10, P = 0.42) or PAI-1 (r = 0.13, P = 0.30), without any influence of race (P > 0.05). Our findings show that maximal exercise unmasks risk factors for cardiovascular disease in Black postmenopausal females.NEW & NOTEWORTHY Exaggerated SBP responses to exercise testing are more frequent in Black than in White male adults. Such responses, if translatable to females, may detect early racial disparities arriving during menopause. Because the endothelium regulates BP and fibrinolytic responses, these could be linked during exercise. At peak exercise, Black but not White postmenopausal females had more exaggerated SPB responses regardless of reduced fibrinolytic potential. Maximal exercise unmasked risk factors for cardiovascular disease in Black postmenopausal females.

Association of hemostasis and inflammation biomarkers with outcomes in acute coronary syndromes.

Plaque rupture triggers a prothrombotic response that is counterbalanced by a fibrinolytic response. d-dimer serves as a marker of both processes. Inflammatory mediators are also released, evidenced with the rise of high-sensitive C reactive protein (hsCRP). Current evidence with these biomarkers has shown conflicting results. Determine an association between d-dimer and hsCRP within hospital and 1-year mortality in patients with acute coronary syndromes. In total, 127 patients were included. In-hospital mortality was 5.7%, and 1-year all-cause and cardiovascular mortality were 14.6 and 9.7%, respectively. The median of admission d-dimer for patients who died during hospital stay was higher than those who survived [4.59 (interquartile ranges (IQR) 1.94-6.05 μg/ml fibrinogen equivalent units (FEU)) vs. 0.56 (IQR 0.31-1.12 μg/ml FEU), P = 0.001]. At 1-year follow-up, the median of admission d-dimer for patients who died was significantly higher than those who survived: 1.55 (IQR 0.91-5.08 μg/ml FEU) vs. 0.53 (IQR 0.29-0.90 μg/ml FEU), P < 0.001. Positive d-dimer vs. negative d-dimer at admission analysis evidenced that almost 25% of the positive patients were dead at 1-year follow-up (22.4 vs. 2.4% negative d-dimer, P = 0.011). Multivariate logistic regression analysis showed that d-dimer has an independent association with 1-year mortality [odds ratio 1.06 (95% confidence interval 1.02-1.10), P = 0.006]. Positive significative correlations between d-dimer and hsCRP levels (R = 0.56, P < 0.001) were found. High levels of admission d-dimer were strongly associated with in-hospital and 1-year mortality. Significant correlations with hsCRP could explain the inflammatory nature that led to poorer outcomes. d-dimer could be useful in risk stratification in acute coronary syndromes; however, a specific threshold should be defined for this type of patient.

Point-of-care diagnosis and monitoring of fibrinolysis resistance in the critically ill: results from a feasibility study

BackgroundFibrinolysisis is essential for vascular blood flow maintenance and is triggered by endothelial and platelet release of tissue plasminogen activator (t-PA). In certain critical conditions, e.g. sepsis, acute respiratory failure (ARF) and trauma, the fibrinolytic response is reduced and may lead to widespread thrombosis and multi-organ failure. The mechanisms underpinning fibrinolysis resistance include reduced t-PA expression and/or release, reduced t-PA and/or plasmin effect due to elevated inhibitor levels, increased consumption and/or clearance. This study in critically ill patients with fibrinolysis resistance aimed to evaluate the ability of t-PA and plasminogen supplementation to restore fibrinolysis with assessment using point-of-care ClotPro viscoelastic testing (VET).MethodsIn prospective, observational studies, whole-blood ClotPro VET evaluation was carried out in 105 critically ill patients. In 32 of 58 patients identified as fibrinolysis-resistant (clot lysis time > 300 s on the TPA-test: tissue factor activated coagulation with t-PA accelerated fibrinolysis), consecutive experimental whole-blood VET was carried out with repeat TPA-tests spiked with additional t-PA and/or plasminogen and the effect on lysis time determined. In an interventional study in a patient with ARF and fibrinolysis resistance, the impact of a 24 h intravenous low-dose alteplase infusion on coagulation and fibrinolysis was prospectively monitored using standard ClotPro VET.ResultsDistinct response groups emerged in the ex vivo experimental VET, with increased fibrinolysis observed following supplementation with (i) t-PA only or (ii) plasminogen and t-PA. A baseline TPA-test lysis time of > 1000 s was associated with the latter group. In the interventional study, a gradual reduction (25%) in serial TPA-test lysis times was observed during the 24 h low-dose alteplase infusion.ConclusionsClotPro viscoelastic testing, the associated TPA-test and the novel experimental assays may be utilised to (i) investigate the potential mechanisms of fibrinolysis resistance, (ii) guide corrective treatment and (iii) monitor in real-time the treatment effect. Such a precision medicine and personalised treatment approach to the management of fibrinolysis resistance has the potential to increase treatment benefit, while minimising adverse events in critically ill patients.Trial registration: VETtiPAT-ARF, a clinical trial evaluating ClotPro-guided t-PA (alteplase) administration in fibrinolysis-resistant patients with ARF, is ongoing (ClinicalTrials.gov NCT05540834; retrospectively registered September 15th 2022).

Fibrinolysis Shutdown and Hypofibrinolysis Are Not Synonymous Terms: The Clinical Significance of Differentiating Low Fibrinolytic States.

Low fibrinolytic activity has been associated with pathologic thrombosis and multiple-organ failure. Low fibrinolytic activity has two commonly associated terms, hypofibrinolysis and fibrinolysis shutdown. Hypofibrinolysis is a chronic state of lack of ability to generate an appropriate fibrinolytic response when anticipated. Fibrinolysis shutdown is the shutdown of fibrinolysis after systemic activation of the fibrinolytic system. There has been interchanging of these terms to describe critically ill patients in multiple settings. This is problematic in understanding the pathophysiology of disease processes related to these conditions. There is also a lack of research on the cellular mediators of these processes. The purpose of this article is to review the on and off mechanisms of fibrinolysis in the context of low fibrinolytic states to define the importance in differentiating hypofibrinolysis from fibrinolysis shutdown. In many clinical scenarios, the etiology of a low fibrinolytic state cannot be determined due to ambiguity if a preceding fibrinolytic activation event occurred. In this scenario, the term "low fibrinolytic activity" or "fibrinolysis resistance" is a more appropriate descriptor, rather than using assumptive of hypofibrinolysis and fibrinolysis shutdown, particularly in the acute setting of infection, injury, and surgery.

Commentary on “The suboptimal fibrinolytic response in COVID‐19 is dictated by high PAI‐1”

Commentary on “The suboptimal fibrinolytic response in COVID‐19 is dictated by high PAI‐1”

The suboptimal fibrinolytic response in COVID‐19 is dictated by high PAI‐1

BackgroundSevere COVID‐19 disease is associated with thrombotic complications and extensive fibrin deposition. This study investigates whether the hemostatic complications in COVID‐19 disease arise due to dysregulation of the fibrinolytic system. MethodsThis prospective study analyzed fibrinolytic profiles of 113 patients hospitalized with COVID‐19 disease with 24 patients with non‐COVID‐19 respiratory infection and healthy controls. Antigens were quantified by Ella system or ELISA, clot lysis by turbidimetric assay, and plasminogen activator inhibitor‐1 (PAI‐1)/plasmin activity using chromogenic substrates. Clot structure was visualized by confocal microscopy. ResultsPAI‐1 and its cofactor, vitronectin, are significantly elevated in patients with COVID‐19 disease compared with those with non‐COVID‐19 respiratory infection and healthy control groups. Thrombin activatable fibrinolysis inhibitor and tissue plasminogen activator were elevated in patients with COVID‐19 disease relative to healthy controls. PAI‐1 and tissue plasminogen activator (tPA) were associated with more severe COVID‐19 disease severity. Clots formed from COVID‐19 plasma demonstrate an altered fibrin network, with attenuated fiber length and increased branching. Functional studies reveal that plasmin generation and clot lysis were markedly attenuated in COVID‐19 disease, while PAI‐1 activity was elevated. Clot lysis time significantly correlated with PAI‐1 levels. Stratification of COVID‐19 samples according to PAI‐1 levels reveals significantly faster lysis when using the PAI‐1 resistant (tPA) variant, tenecteplase, over alteplase lysis. ConclusionThis study shows that the suboptimal fibrinolytic response in COVID‐19 disease is directly attributable to elevated levels of PAI‐1, which attenuate plasmin generation. These data highlight the important prognostic potential of PAI‐1 and the possibility of using pre‐existing drugs, such as tenecteplase, to treat COVID‐19 disease and potentially other respiratory diseases.

This Month in Anesthesiology

This Month in Anesthesiology

Temporal Transitions in Fibrinolysis after Trauma: Adverse Outcome Is Principally Related to Late Hypofibrinolysis.

The relationship between late clinical outcomes after injury and early dynamic changes between fibrinolytic states is not fully understood. The authors hypothesized that temporal transitions in fibrinolysis states using rotational thromboelastometry (ROTEM) would aid stratification of adverse late clinical outcomes and improve understanding of how tranexamic acid modulates the fibrinolytic response and impacts mortality. The authors conducted a secondary analysis of previously collected data from trauma patients enrolled into an ongoing prospective cohort study (International Standard Randomised Controlled Trial Number [ISRCTN] 12962642) at a major trauma center in the United Kingdom. ROTEM was performed on admission and at 24 h with patients retrospectively grouped into three fibrinolysis categories: tissue factor-activated ROTEM maximum lysis of less than 5% (low); tissue factor-activated ROTEM maximum lysis of 5 to 15% (normal); or tissue factor-activated ROTEM maximum lysis of more than 15% (high). Primary outcomes were multiorgan dysfunction syndrome and 28-day mortality. Seven-hundred thirty-one patients were included: 299 (41%) were treated with tranexamic acid and 432 (59%) were untreated. Two different cohorts with low-maximum lysis at 24 h were identified: (1) severe brain injury and (2) admission shock and hemorrhage. Multiple organ dysfunction syndrome was greatest in those with low-maximum lysis on admission and at 24 h, and late mortality was four times higher than in patients who remained normal during the first 24 h (7 of 42 [17%] vs. 9 of 223 [4%]; P = 0.029). Patients that transitioned to or remained in low-maximum lysis had increased odds of organ dysfunction (5.43 [95% CI, 1.43 to 20.61] and 4.85 [95% CI, 1.83 to 12.83], respectively). Tranexamic acid abolished ROTEM hyperfibrinolysis (high) on admission, increased the frequency of persistent low-maximum lysis (67 of 195 [34%]) vs. 8 of 79 [10%]; P = 0.002), and was associated with reduced early mortality (28 of 195 [14%] vs. 23 of 79 [29%]; P = 0.015). No increase in late deaths, regardless of fibrinolysis transition patterns, was observed. Adverse late outcomes are more closely related to 24-h maximum lysis, irrespective of admission levels. Tranexamic acid alters early fibrinolysis transition patterns, but late mortality in patients with low-maximum lysis at 24 h is not increased.

Determination role of some biomarkers tests for severe SARS-COV-2 infections in babylon province/IRAQ

In a series of 30 SARS-COV-2 infected patients whom clinically proven as severe pulmonary infection form. These were found with male/female ratio of 1:1. The age range of below 50 years old account for 60% and those of above 50 years old constitute the remaining 40%. They were the residents of Merjan Teaching Hospital/ Babylon Province/Iraq, to the period of March to April 2021 and primary screen by PCR for Sars-cov-2 RNA genes, in public health central laboratory found to be positive. The over- all laboratory investigation were; D –dimer, Ferritin, LDH, acute phase reactant C, and IL6. LDH was tempted to probe the immune mediated pulmonary tissue injury (367.48 U/L.), ferritin response may indicate hemolytic and acute phase reactant expressed as hyper-inflammation (331.1 ng/L.). |The D-dimer shed a light on the fibrino-lytic responses (6049 ng/L.) post to the immune-thrombotic overreactions, where IL6 levels give a clue to the state of hyper-cytokinemia (171.92 pg/L.). The overall immune status of these patients was as; Hyper-inflammatory and immune overreaction. The inflammatory and immune herd plots were of skewed distribution types.

Association of biomarkers of fibrinolysis and inflammation with mortality in acute coronary syndrome

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Universidad de Buenos Aires. Introduction in acute coronary syndromes (ACS), plaque rupture elicits a prothrombotic response that is counter balanced by a fibrinolytic response. D-dimer (DD) serves as a marker of both processes, reflecting thrombin activity and through cross-linked fibrin degradation. Inflammatory mediators are also involved, evidenced with the rise of C-reactive protein (CPR) levels, enhancing the prothrombotic and proatherogenic endothelial vascular response. Current evidence with these biomarkers has shown conflicting results with no conclusive impact on cardiovascular outcomes, risk stratification nor potential treatments. Purpose our aim was to determine an association between DD and CRP with in-hospital and 1-year mortality in patients with ACS. Methods observational study of patients admitted to a coronary care unit with ACS and elevated troponin. Clinical characteristics, in-hospital and 1-year outcomes and serum levels at admission of DD and CRP were assessed. Results we included 127 patients with ACS. Mean age was 68.4 ± 12.8 years and 61% were male, 57.7% had hypertension, 17.1% had dyslipidemia, 25.2% had diabetes and 17.9% had previous myocardial infarction. Most patients received DAPT and 67.5% underwent PCI or CABG during the index hospitalization. In-hospital mortality was 5.7% and 1-year all-cause and cardiovascular mortality were 14.6% and 9.7% respectively. The median of admission DD for patients who died during hospital stay was higher than those who survived (4.59 [IQR 1.94-6.05 ug/ml FEU] vs 0.56 [IQR 0.31-1.12 ug/ml FEU], p = 0.001). At 1-year follow-up, the median of admission DD for patients who died was significantly higher than those who survived: 1.55 (IQR 0.91-5.08 ug/ml FEU) vs. 0.53 (IQR 0.29-0.90 ug/ml FEU), p &amp;lt; 0.001 (figure A). We analyzed positive DD vs. negative DD at admission, with 0.5 ug/ml FEU cut-off value, almost a quarter of the positive patients were dead at 1-year follow up (22.4% vs. 2.4% negative DD, p= 0.011). We found a positive significative correlation between DD and CRP levels (R = 0.56, p &amp;lt; 0.001) (figure B). Conclusion high levels of DD at admission were strongly associated with in-hospital and 1-year mortality. Significant correlations with CRP could explain the inflammatory nature that lead to poorer outcomes. DD could be useful in risk-stratification in ACS; however, a specific threshold should be defined for this type of patients. Abstract Figure A. Figure B.

The Central Role of Fibrinolytic Response in COVID-19-A Hematologist's Perspective.

The novel coronavirus disease (COVID-19) has many characteristics common to those in two other coronavirus acute respiratory diseases, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). They are all highly contagious and have severe pulmonary complications. Clinically, patients with COVID-19 run a rapidly progressive course of an acute respiratory tract infection with fever, sore throat, cough, headache and fatigue, complicated by severe pneumonia often leading to acute respiratory distress syndrome (ARDS). The infection also involves other organs throughout the body. In all three viral illnesses, the fibrinolytic system plays an active role in each phase of the pathogenesis. During transmission, the renin-aldosterone-angiotensin-system (RAAS) is involved with the spike protein of SARS-CoV-2, attaching to its natural receptor angiotensin-converting enzyme 2 (ACE 2) in host cells. Both tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) are closely linked to the RAAS. In lesions in the lung, kidney and other organs, the two plasminogen activators urokinase-type plasminogen activator (uPA) and tissue plasminogen activator (tPA), along with their inhibitor, plasminogen activator 1 (PAI-1), are involved. The altered fibrinolytic balance enables the development of a hypercoagulable state. In this article, evidence for the central role of fibrinolysis is reviewed, and the possible drug targets at multiple sites in the fibrinolytic pathways are discussed.

Impaired fibrinolysis in critically ill COVID-19 patients

BackgroundCritically ill coronavirus disease 2019 (COVID-19) patients present with a hypercoagulable state with high rates of macrovascular and microvascular thrombosis, for which hypofibrinolysis might be an important contributing factor. MethodsWe retrospectively analysed 20 critically ill COVID-19 patients at Innsbruck Medical University Hospital whose coagulation function was tested with ClotPro® and compared with that of 60 healthy individuals at Augsburg University Clinic. ClotPro is a viscoelastic whole blood coagulation testing device. It includes the TPA test, which uses tissue factor (TF)-activated whole blood with added recombinant tissue-derived plasminogen activator (r-tPA) to induce fibrinolysis. For this purpose, the lysis time (LT) is measured as the time from when maximum clot firmness (MCF) is reached until MCF falls by 50%. We compared COVID-19 patients with prolonged LT in the TPA test and those with normal LT. ResultsCritically ill COVID-19 patients showed hypercoagulability in ClotPro assays. MCF was higher in the EX test (TF-activated assay), IN test (ellagic acid-activated assay), and FIB test (functional fibrinogen assay) with decreased maximum lysis (ML) in the EX test (hypofibrinolysis) and highly prolonged TPA test LT (decreased fibrinolytic response), as compared with healthy persons. COVID-19 patients with decreased fibrinolytic response showed higher fibrinogen levels, higher thrombocyte count, higher C-reactive protein levels, and decreased ML in the EX test and IN test. ConclusionCritically ill COVID-19 patients have impaired fibrinolysis. This hypofibrinolytic state could be at least partially dependent on a decreased fibrinolytic response.

Effect of Multiple Doses of Intravenous Tranexamic Acid on Perioperative Blood Loss in Total Knee Arthroplasty: A Randomized Controlled Study

ObjectiveTo identify the efficacy and safety of multiple doses of intravenous tranexamic acid (IV‐TXA) following primary total knee arthroplasty (TKA) with a tourniquet.MethodsThis is a single‐blind randomized controlled study that recruited osteoarthritis patients who had undergone primary unilateral TKA from May 2019 to May 2020 at our medical center. A total of 300 patients were randomly divided into three groups to receive: one dose (1 g) of IV‐TXA before skin incision combined with one dose (1.5 g) of intra‐articular tranexamic acid（IA‐TXA) followed by a single dose of IV‐TXA (1 g) for 3 h (group A); two doses of IV‐TXA (1 g) for 3 and 6 h (group B); or three doses of IV‐TXA (1 g) for 3, 6, and 12 h (group C) postoperatively. TKA with a tourniquet was performed by the same surgical team. The primary outcomes were total blood cell loss (TBL), hidden blood loss (HBL), maximum hemoglobin (Hb) drop, and transfusion rate. Secondary outcomes were levels of C‐reactive protein (CRP) and D‐dimer, and the incidence of postoperative complications. One‐way analysis of variance, subgroup analysis, and multivariate correlation analysis were used to calculate the differences among the three groups.ResultsThe study included 56 male and 244 female patients aged 60–80 years. The mean TBL, the mean HBL, and the maximum Hb drop in group C (471.2 ± 190.6 mL, 428.4 ± 190.3 mL, and 21.2 ± 3.8 g/L, respectively) were significantly lower than those in groups B (563.4 ± 224.6 mL, P = 0.030; 519.9 ± 226.4 mL, P = 0.033; and 23.2 ± 4.1 g/L, P = 0.001, respectively), and A (651.6 ± 254.1 mL, P < 0.001; 607.1 ± 254.3 mL, P < 0.001; and 25.1 ± 4.3 g/L, P < 0.001, respectively). No transfusions were required. The postoperative acute inflammatory reaction was less problematic for patients in Group C, and the incidence of thromboembolic events was similar among the groups (P > 0.05). In addition, there were positive correlations between the HBL and the tourniquet inflation time (r = 0.844, P < 0.001). Similarly, the level of CRP on POD1 (r = 0.393, P < 0.001) and POD3 (r = 0.149, P = 0.010), and the level of D‐dimer on POD1 (r = 0.382, P < 0.001) were positively correlated with the HBL.ConclusionThree doses of postoperative IV‐TXA decreased blood loss and diminished the postoperative inflammatory and fibrinolytic response more than a single dose or two doses in elderly patients following TKA without increasing the incidence of adverse events.

Liver X Receptor (LXR) Is a Novel and Reversible Regulator of Trauma-Induced Coagulopathy

Trauma-induced coagulopathy (TIC) manifests as a bimodal disruption of normal fibrinolysis, where at the two extremes, fibrinolytic shutdown (TICFS) places the patient at increased risk for thromboembolism and post-injury multiple organ failure, and systemic hyperfibrinolysis (TICHF) results in excessive bleeding. Plasma proteomic profiles for 65 trauma patients were used to identify changes in the patient's plasma protein profile stratifying them by risk for TIC. A strong correlation was seen between total plasma protein concentration of individual patients and the concentration of coagulation proteins within that patient, suggesting that trauma-induced coagulation may be affected through a mechanism that controls the efflux of many coagulation proteins into the plasma (Figure 1). Pathway analysis, in addition to elucidating changes in the coagulation cascade, identified several proteins that are known to be regulated by the Liver X receptor/Retinoid X receptor (LXR/RXR), suggesting that LXR/RXR-mediated activity may regulate TIC (p=9.03E-26). Validation experiments in a rat model revealed that fibrinolytic response to an LXR antagonist and/or agonist can be observed in less than 60 minutes (Figure 2). Additionally, we show through reciprocal rescue of fibrinolysis that the TIC phenotypes (TICHF and TICFS) are one continuum and are ultimately co-reversible, where the reduced LXR signaling that causes sequestration of blood factors in the liver leading to excess bleeding or induced LXR signaling that causes excess efflux leading to thrombosis can be reversed through administration of the LXR agonist or antagonist, respectively. Thus, as modulation of LXR shows co-reversibility and rapid response, induction/inhibition of the LXR pathway provides a direct and novel therapeutic intervention in severely injured patients at risk for TIC. Disclosures No relevant conflicts of interest to declare.

Comprehensive Characterization of the Vascular Effects of Cisplatin-Based Chemotherapy in Patients With Testicular Cancer

BackgroundCisplatin-based chemotherapy increases the risk of cardiovascular and renal disease. ObjectivesWe aimed to define the time course, pathophysiology, and approaches to prevent cardiovascular disease associated with cisplatin-based chemotherapy. MethodsTwo cohorts of patients with a history of testicular cancer (n = 53) were recruited. Cohort 1 consisted of 27 men undergoing treatment with: 1) surveillance; 2) 1 to 2 cycles of bleomycin, etoposide, and cisplatin (BEP) chemotherapy (low-intensity cisplatin); or 3) 3 to 4 cycles of BEP (high-intensity cisplatin). Endothelial function (percentage flow-mediated dilatation) and cardiovascular biomarkers were assessed at 6 visits over 9 months. Cohort 2 consisted of 26 men previously treated 1 to 7 years ago with surveillance or 3 to 4 cycles BEP. Vasomotor and fibrinolytic responses to bradykinin, acetylcholine, and sodium nitroprusside were evaluated using forearm venous occlusion plethysmography. ResultsIn cohort 1, the percentage flow-mediated dilatation decreased 24 h after the first cisplatin dose in patients managed with 3 to 4 cycles BEP (10.9 ± 0.9 vs. 16.7 ± 1.6; p < 0.01) but was unchanged from baseline thereafter. Six weeks after starting 3 to 4 cycles BEP, there were increased serum cholesterol levels (7.2 ± 0.5 mmol/l vs. 5.5 ± 0.2 mmol/l; p = 0.01), hemoglobin A1c (41.8 ± 2.0 mmol/l vs. 35.5 ± 1.2 mmol/l; p < 0.001), von Willebrand factor antigen (62.4 ± 5.4 mmol/l vs. 45.2 ± 2.8 mmol/l; p = 0.048) and cystatin C (0.91 ± 0.07 mmol/l vs. 0.65 ± 0.09 mmol/l; p < 0.01). In cohort 2, intra-arterial bradykinin, acetylcholine, and sodium nitroprusside caused dose-dependent vasodilation (p < 0.0001). Vasomotor responses, endogenous fibrinolytic factor release, and cardiovascular biomarkers were not different in patients managed with 3 to 4 cycles of BEP versus surveillance. ConclusionsCisplatin-based chemotherapy induces acute and transient endothelial dysfunction, dyslipidemia, hyperglycemia, and nephrotoxicity in the early phases of treatment. Cardiovascular and renal protective strategies should target the early perichemotherapy period. (Clinical Characterisation of the Vascular Effects of Cis-platinum Based Chemotherapy in Patients With Testicular Cancer [VECTOR], NCT03557177; Intermediate and Long Term Vascular Effects of Cisplatin in Patients With Testicular Cancer [INTELLECT], NCT03557164)

Comparative Study of Fibrinolytic Response amongst Malarious Pregnant and Non Malarious Subjects in Rivers State, Nigeria

Aim: The study was designed to comparatively assess the degree of fibrinolytic response amongst malaria-positive pregnant women, and non-malaria positive subjects in Rivers State, Nigeria.&#x0D; Methods: The study area covered University of Port Harcourt Teaching Hospital, Port Harcourt [UPTH] and Rivers State University Teaching Hospital, [RSUTH] both in Port Harcourt metropolis Rivers State. It was a cross-sectional study carried out on a total of two hundred and forty female attendees at the obstetrics and gynecology clinics of the two hospitals. The subjects were grouped into three comprising of eighty subjects in each group; malarious pregnant women, non- malarious pregnant women and apparently healthy non-pregnant women. Venous blood sample measuring 5 milliliter volume was drawn from each subject, The sample was dispensed into two separate EDTA anticoagulant bottles, 3 milliliter and 2 milliliter meant for measuring the levels of markers of fibrinolysis which were Plasminogen, Plasminogen activator inhibitor-1, Plasminogen activator inhibitor-2, Tissue Plasminogen activator, alpha-2-antiplasmin, D-dimers and fibrinogen, and preparation of blood films for malaria microscopy respectively.&#x0D; Results: Fibrinogen result; 760.44±16.18 ng/ml of malaria-positive pregnant women was elevated compared to the malaria-negative women; 697.70±18.84 ng/ml and the non-pregnant control values of 704.73±15.25 ng/ml. These values were significantly different [P&lt;.011] between the study groups. Results of tissue plasminogen activator [tPA]; 46.39±2.69 ng/ml, D-dimer; 77.64±6.94 ng/ml, plasminogen activator inhibitor-1 [PAI-1]; 89.73±2.14 ng/ml, plasminogen activator inhibitor-2 [PAI-2]; 568.00±12.51 ng/ml, plasminogen; 23.82±0.75 ng/ml and 2-antiplasmin; 1314.06±34.64 ng/ml of the malaria-positive pregnant women were significantly different [P=0.0001] from non-positive pregnant women; tPA; 28.87±1.38 ng/ml, D-dimer; 53.90±1.18 ng/ml., PAI-1; 80.00± 1.81 ng/ml, PAI-2; 456.31±5.94 ng/ml, Plasminogen; 16.63±0.67 ng/ml and 2-antiplasmin; 1130.61±29.74 ng/ml . Both results were significantly different [P=0.0001] from the non-pregnant control group; tPA; 31.34±1.64 ng/ml, D-dimer; 30.24±1.04 ng/ml, PAI-1; 65,47±2,33 ng/ml, PAI-2; 427.86±6.95 ng/ml, plasminogen; 16.49±0.04 ng/ml and 2-antiplasmin; 1016.98±24.51 ng/ml.&#x0D; Conclusion: The study witnessed significantly high concentrations of fibrinolytic markers in malaria-positive pregnant women. This could be due to compromised endothelial cell function resulting to overproduction of biomarkers of fibrinolysis. The implication is thrombus formation and excessive bleeding in pregnancy which could lead to miscarriages, fetal death or maternal mortality.