Blood test dynamics in hospitalized COVID-19 patients: Potential utility of D-dimer for pulmonary embolism diagnosis.

BACKGROUND: A higher incidence of thrombotic events, mainly pulmonary embolism (PE), has been reported in hospitalized patients with COVID-19. The main objective was to assess clinical and laboratory differences in hospitalized COVID-19 patients according to occurrence of PE. METHODS: This retrospective study included all consecutive patients hospitalized with COVID-19 who underwent a computed tomography (CT) angiography for PE clinical suspicion. Clinical data and median blood test results distributed into weekly periods from COVID-19 symptoms onset, were compared between PE and non-PE patients. RESULTS: Ninety-two patients were included, 29 (32%) had PE. PE patients were younger (63.9 (SD 13.7) vs 69.9 (SD 12.5) years). Clinical symptoms and COVID-19 CT features were similar in both groups. PE was diagnosed after a mean of 20.0 (SD 8.6) days from the onset of COVID-19 symptoms. Corticosteroid boluses were more frequently used in PE patients (62% vs. 43%). No patients met ISTH DIC criteria. Any parameter was statistically significant or clinically relevant except for D-Dimer when comparing both groups. Median values [IQR] of D-dimer in PE vs non-PE patients were: week 2 (2010.7 [770.1-11208.9] vs 626.0 [374.0-2382.2]; p = 0.004); week 3 (3893.1 [1388.2-6694.0] vs 1184.4 [461.8-2447.8]; p = 0.003); and week 4 (2736.3 [1202.1-8514.1] vs 1129.1 [542.5-2834.6]; p = 0.01). Median fold-increase of D-dimer between week 1 and 2 differed between groups (6.64 [3.02-23.05] vs 1.57 [0.64-2.71], p = 0.003); ROC curve AUC was 0.879 (p = 0.003) with a sensitivity and specificity for PE of 86% and 80%, respectively. CONCLUSIONS: Among hospitalized COVID-19 patients, D-dimer levels are higher at weeks 2, 3 and 4 after COVID-19 symptom onset in patients who develop PE. This difference is more pronounced when the fold increase between weeks 1 and 2 is compared.

Multiple-Dose Intravenous Tranexamic Acid Further Reduces Hidden Blood Loss After Total Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The most appropriate dose of tranexamic acid in total hip arthroplasty (THA) has not been decided. This study was conducted to evaluate the clinical effects of multiple-dose intravenous tranexamic acid (IV-TXA) in THA. METHODS: One hundred fifty patients were randomized to receive one dose of IV-TXA before incision, followed by 2 doses of IV-TXA (group A), or 3 doses of IV-TXA (group B), or 4 doses of IV-TXA (group C) at 3-hour intervals. The primary outcome was hidden blood loss (HBL). Other outcome measurements such as total blood loss, maximum hemoglobin (Hb) drop, postoperative lowest Hb level, fibrinolysis parameter (D-dimer), inflammatory factor (interleukin-6), transfusion rate, length of stay, and complications were also compared. RESULTS: The mean HBL, total blood loss, and maximum Hb drop were significantly lower in group C than in groups B and A. Such differences were also detected between groups B and A. The postoperative lowest Hb level was significantly higher in group C. D-dimer and interleukin-6 in group C were significantly lower than in groups B and A at 24 and 48 hours postoperatively. Such differences were also significant between groups B and A. There was no significant difference in length of stay among groups. No patient underwent blood transfusion during hospitalization. No episodes of deep venous thrombosis or pulmonary embolism occurred in all cases. CONCLUSION: The 5-dose IV-TXA regimen can further diminish HBL, decrease maximum Hb drop, provide additional fibrinolysis control, and ameliorate postoperative inflammatory response following THA.

Combined peri-ischemic administration of Bß15-42 in treating ischemia reperfusion injury of the mouse kidney.

The disruption of endothelial integrity is a crucial step for the development of vascular leakage and consequently ischemia-reperfusion injury (IRI). Regarding the molecular cell-cell interaction, the fibrinopeptide Bß15-42 prevents vascular leakage by stabilizing the inter-endothelial junctions via association with the vascular endothelial-cadherin. In a previous study we showed that a renoprotective effect in early IRI may be achieved by intravenous administration of Bß15-42 at the time of reperfusion. We now aimed to investigate whether additional pre-ischemic application of Bß15-42 could enhance this effect. Therefore C57BL/6 mice were subjected to 0.5h bilateral renal ischemia followed by reperfusion. The animals were randomized into 6 groups (n=6): two control groups treated with i.v. administration of NaCl at reperfusion for 0.5h (NaCl 1h) and 2.5h (NaCl 3h), two groups with Bß15-42 at reperfusion for 0.5h (Bß(rep) 1h) and 2.5h (Bß(rep) 3h), and two groups with administration of Bß15-42 immediately pre-ischemic as well as at reperfusion for 0.5h (Bß(peri) 1h) and 2.5h (Bß(peri) 3h). We found that both Bß(rep) and Bß(peri) mice displayed reduced early renal damage compared with NaCl treated mice. However, there was no further reduction of the IR damage through added pre-ischemic application of Bß15-42. Overall, we detected significantly reduced endothelial activation, lower tissue infiltration of neutrophils as well as lower tissue levels of neutrophil gelatinase-associated lipocalin (NGAL) in all mice treated with Bß15-42 compared to mice treated with NaCl. Our data confirm the renoprotective effect of Bß15-42 in the early therapeutic treatment of acute kidney injury due to ischemia and reperfusion. However, a combined pre-and post-ischemic administration of Bß15-42 appears to provide no additional benefit compared with a sole administration at reperfusion.

D-dimer for the diagnosis of upper extremity deep and superficial venous thrombosis.

BACKGROUND: D-dimer role is well established in the diagnostic work-up for lower limb deep vein thrombosis (DVT), however it has not been formally tested for clinically suspected upper extremity DVT and/or superficial vein thrombosis (SVT). AIM: To ascertain D-dimer diagnostic accuracy for upper extremity DVT and/or SVT. STUDY DESIGN: We performed a single centre management study in outpatients referred by emergency or primary care physicians for clinically suspected upper extremity DVT. All patients underwent D-dimer testing (cut-off value: ≤500 ng/mL), and a B-mode and color Doppler ultrasonography examination. In case of either technical problems or anatomical barriers, ultrasonography was repeated after 5-7 days. All patients were followed up for three months for the occurrence of symptomatic DVT and/or SVT and/or pulmonary embolism. RESULTS: We enrolled 239 patients (F: 63.6%; mean±SD age: 58.3±16.8). At the initial diagnostic work-up, DVT was detected in 24 (10%) patients while SVT in 35 (14.6%) patients. During follow-up, one upper extremity DVT was found. D-dimer levels were higher in patients with DVT than in those without. Sensitivity and specificity of D-dimer for DVT were 92% (95%CI: 73-99%) and 60% (95%CI: 52-67%) respectively, with a negative predictive value of 98% (95%CI: 93-100%), whereas for SVT they were 77% (95%CI: 59-89%) and 60% (95%CI: 52-67%) respectively, with a negative predictive value of 93% (95%CI: 86-97%). CONCLUSIONS: D-dimer has a negative predictive value ≥93% for excluding DVT in symptomatic outpatients and it can be a useful test in the diagnostic work-up of suspected upper extremity DVT.

The small fibrinopeptide Bß15-42 as renoprotective agent preserving the endothelial and vascular integrity in early ischemia reperfusion injury in the mouse kidney.

Disruption of the renal endothelial integrity is pivotal for the development of a vascular leak, tissue edema and consequently acute kidney injury. Kidney ischemia amplifies endothelial activation and up-regulation of pro-inflammatory mechanisms. After restoring a sufficient blood flow, the kidney is damaged through complex pathomechanisms that are classically referred to as ischemia and reperfusion injury, where the disruption of the inter-endothelial connections seems to be a crucial step in this pathomechanism. Focusing on the molecular cell-cell interaction, the fibrinopeptide Bß15-42 prevents vascular leakage by stabilizing these inter-endothelial junctions. The peptide associates with vascular endothelial-cadherin, thus preventing early kidney dysfunction by preserving blood perfusion efficacy, edema formation and thus organ dysfunction. We intended to demonstrate the early therapeutic benefit of intravenously administered Bß15-42 in a mouse model of renal ischemia and reperfusion. After 30 minutes of ischemia, the fibrinopeptide Bß15-42 was administered intravenously before reperfusion was commenced for 1 and 3 hours. We show that Bß15-42 alleviates early functional and morphological kidney damage as soon as 1 h and 3 h after ischemia and reperfusion. Mice treated with Bß15-42 displayed a significantly reduced loss of VE-cadherin, indicating a conserved endothelial barrier leading to less neutrophil infiltration which in turn resulted in significantly reduced structural renal damage. The significant reduction in tissue and serum neutrophil gelatinase-associated lipocalin levels reinforced our findings. Moreover, renal perfusion analysis by color duplex sonography revealed that Bß15-42 treatment preserved resistive indices and even improved blood velocity. Our data demonstrate the efficacy of early therapeutic intervention using the fibrinopeptide Bß15-42 in the treatment of acute kidney injury resulting from ischemia and reperfusion. In this context Bß15-42 may act as a potent renoprotective agent by preserving the endothelial and vascular integrity.

Effects of FX06 in vitro on platelet, coagulation, and fibrinolytic biomarkers in volunteers and patients with documented coronary artery disease.

FX06 is a naturally occurring fibrin-derived peptide demonstrated to confer cytoprotection in the setting of primary percutaneous coronary intervention. Because the effect of FX06 on human platelet, coagulation, and fibrinolysis biomarkers (PCFB) is unknown but is important for further clinical development, we evaluated how FX06 affects PCFB. The in vitro effects of the whole-blood pre-incubation with escalating concentrations of FX06 (4, 25, and 75 µg/mL) were assessed in aspirin-naïve healthy volunteers (n = 10), those with multiple risk factors for vascular disease (n = 10), and patients with documented coronary artery disease (n = 10). The last two groups were treated with aspirin (81 mg/daily). Thirty-two variables of PCFB were measured with the vehicle and for each chosen FX06 dose. Pretreatment of blood samples with FX06 resulted in a moderate but significant and mostly dose-dependent increases of platelet aggregation induced by adenosine diphosphate and collagen. Similarly, the closure time was reduced, suggesting share-induced activation, PECAM-1, GP Ib, GP IIb/IIIa activity, and vitronectin receptors, which were also up-regulated. In contrast, P-selectin and GPIIb antigen expression were reduced after FX06. All other PCFB were predominantly unaffected by FX06, with the exception of the increased plasminogen, decreased protein C activity, and activated von Willebrand factor. We conclude that in the therapeutic range, FX06 in vitro mildly affects hemostasis by way of mostly activating platelets. Applying moderate concomitant antiplatelet strategies should be considered for the adequate protection from vascular thrombotic events in patients treated with FX06. Similar ex vivo study in patients receiving aspirin and clopidogrel is warranted.

Effect of a vascular endothelial cadherin antagonist in a rat lung transplant model.

BACKGROUND: Adherens junctions are critically important in control of endothelial cell permeability. Bß15-42 is a peptide product of fibrin degradation that binds to vascular endothelial cadherin, the major component of endothelial adherens junctions. We tested the hypothesis that Bß15-42 improves lung function in our rat lung transplant model. METHODS: Bß15-42 was administered to donors before lung retrieval and to recipients by continuous intravenous infusion, or just to recipients, or neither. Recipients were monitored, anesthetized and ventilated, for 6 hours. Outcome measures were indices of lung function (edema [wet-to-dry weight ratio], oxygenation, dynamic compliance) and bronchoalveolar fluid measures of inflammation (protein, cell count, differential, and cytokines). RESULTS: Bß15-42 therapy was associated with improved graft lung function, including less edema, and improved oxygenation and airway pressure, particularly if Bß15-42 was administered to both the donor and recipient. However, Bß15-42 had little or no effect on bronchoalveolar fluid measures of inflammation. Analysis of bronchoalveolar fluid protein concentration showed Bß15-42 may enhance alveolar fluid clearance. CONCLUSIONS: Bß15-42 may be a useful therapy to reduce edema and improve graft function after lung transplant, alone or as an adjunct to other therapies.

Platelet count kinetics following interruption of antiretroviral treatment.

OBJECTIVES: To investigate the mechanisms of platelet kinetics in the Strategies for Management of Antiretroviral Therapy (SMART) study that demonstrated excess mortality with CD4 guided episodic antiretroviral therapy (ART) drug conservation compared with continuous treatment viral suppression. Follow-up analyses of stored plasma samples demonstrated increased activation of both inflammatory and coagulation pathways after stopping ART. DESIGN: SMART patients from sites that determined platelets routinely. METHODS: Platelet counts were retrospectively collected from 2206 patients from visits at study entry, and during follow-up. D-dimer levels were measured at study entry, month 1, and 2. RESULTS: Platelet levels decreased in the drug conservation group following randomization, but remained stable in the viral suppression group [median (IQR) decline from study entry to month 4: -24 000/µl (-54 000 to 4000) vs. 3000 (-22 000 to 24 000), respectively, P < 0.0001)] and the rate of developing thrombocytopenia (<100 000/µl) was significantly higher in the drug conservation vs. the viral suppression arm (unadjusted drug conservation/viral suppression [HR (95%CI) = 1.8 (1.2-2.7)]. The decline in platelet count among drug conservation participants on fully suppressive ART correlated with the rise in D-dimer from study entry to either month 1 or 2 (r = -0.41; P = 0.02). Among drug conservation participants who resumed ART 74% recovered to their study entry platelet levels. CONCLUSION: Interrupting ART increases the risk of thrombocytopenia, but reinitiation of ART typically reverses it. Factors contributing to declines in platelets after interrupting ART may include activation of coagulation pathways or HIV-1 replication itself. The contribution of platelets in HIV-related procoagulant activity requires further study.

Uso de fibrinógeno humano en la generación de soportes para la obtención de equivalentes tisulares / Use of human fibrinogen in the generation of scaffold for obtaining Tissue equivalents

Desde sus orígenes, la Ingeniería de Tejidos ha buscado diversos materiales que puedan ser utilizados para la generación de soportes que sirvan para el anclaje, proliferación y diferenciación celular que conduzcan a la obtención de tejidos humanos. Muchos materiales de tipo cerámico, polimérico y metálico se han evaluado, pero hasta la fecha muchos de ellos han sido rechazados por diversas razones, entre otras su escasa biocompatibilidad y biodegradabilidad, la respuesta inmune generada, la baja resistencia mecánica o el riesgo de transmisión de virus o priones. El fibrinógeno es una proteína presente en el plasma sanguíneo que puede ser utilizada para la generación de soportes tridimensionales que favorezcan el crecimiento de células; se obtiene a partir del propio paciente, bancos de sangre o como proteína purificada (Tisseel® o Tissucol®, Laboratorios Baxter). El fibrinógeno evita el desencadenamiento de una respuesta inmunológica y el uso de productos xenogénicos. Debido a la estructura proteica, la adhesión y proliferación celular se ven favorecidas dando excelentes resultados en la generación de equivalentes de piel, cartílago, córnea y reemplazos cardiacos en aplicaciones in vitro e in vivo. Como desventajas presenta su rápida degradación y su baja resistencia mecánica; sin embargo, en los últimos años se han venido evaluando mezclas con algunos biopolímeros como ácido poliláctico (PLLA), ácido poli-glicólico (PGA) y alginato de sodio. Esta revisión presenta algunas de las principales aplicaciones del fibrinógeno en Ingeniería de Tejidos.

Since its origin, Tissue Engineering has sought various materials that can be used for generation of scaffolds that serve to anchor, proliferation and cell differentiation leading to the production of human tissues. Many materials such as ceramic, polymeric and metal type have been evaluated to date but many have been rejected for various reasons, including its limited biocompatibility and biodegradability, immune response generated, low mechanical strength or the risk of transmission of virus or prions. Fibrinogen is a protein present in blood plasma that can be used to generate three-dimensional scaffolds that favors growth of cells, it is obtained from the patient itself, bank of blood or purified protein (Tisseel® or Tissucol®, Laboratorios Baxter). Fibrinogen acts slowing or reversing the immune response and avoiding the use of xenogeneic materials. Because the protein structure, adhesion and cell proliferation is favored with excellent results in the generation of skin equivalents, cartilage, cornea and even heart replacements in vitro and in vivo. The disadvantages presented are the rapid degradation and low mechanical strength, but in recent years it has been evaluating some biopolymer mixtures as polylactic acid (PLLA), poly-glycolic acid (PGA) and sodium alginate. This review presents some of the main applications of fibrinogen in Tissue Engineering.

[Results of fibrin clot application for acceleration of regeneration of the damaged mandible in experiment].

The processes of regeneration of the damaged rat bottom jaw bone after application of enriched thrombocytes a fibrin clot were studied by morphological and radiovisiographic methods. At a natural course of regeneration the artificial aperture of bone was filled with blood and there the blood clot was formed. After 1 week the separate bone islets of a young tissue occurred in bone defect. In 2-3 weeks the aperture in a bottom jaw bone was completely closed by a young bone tissue. After operation with filling of bone bottom jaw defect by fibrin clot there was no formation of a blood clot. Already after 1 week the bone tissue defect was filled by the merged islets of again generated bone. By second week after fibrin use the further formation of bone tissue in defect and formation of a bone callosity was noted.

Bß(15-42) attenuates the effect of ischemia-reperfusion injury in renal transplantation.

Renal ischemia-reperfusion contributes to reduced renal allograft survival. The peptide Bß(15-42), a breakdown product of fibrin, attenuates inflammation induced by ischemia-reperfusion in the heart by competitively blocking the binding of leukocytes to endothelial VE-cadherin, but whether it could improve outcomes in renal transplantation is unknown. Here, we tested the ability of Bß(15-42) to ameliorate the effects of renal ischemic injury during allogenic kidney transplantation in mice. In our renal transplantation model (C57BL/6 into BALB/c mice), treatment with Bß(15-42) at the time of allograft reperfusion resulted in significantly improved survival of recipients during the 28-day follow-up (60% versus 10%). Bß(15-42) treatment decreased leukocyte infiltration, expression of endothelial adhesion molecules, and proinflammatory cytokines. Treatment significantly attenuated allogenic T cell activation and reduced cellular rejection. Moreover, Bß(15-42) significantly reduced tubular epithelial damage and apoptosis, which we reproduced in vitro. These data suggest that Bß(15-42) may have therapeutic potential in transplant surgery by protecting grafts from ischemia-reperfusion injury.

[Individualized "minimal invasive" anticoagulation controlled with D-dimer-antigen testing - a concept]. / Individualisierte "minimal invasive" Antikoagulation unter Kontrolle von D-Dimer-Antigen-Bestimmungen. Ein Konzept.

The aim of the proposed concept is to use anticoagulant therapy in prophylaxis and therapy of thromboembolic events only to an extent that the coagulation activation is just not any longer detectable. It results an individualized anticoagulation tailored to the coagulation activation of the patient (individualized "minimal invasive" anticoagulation). Intensity and control of efficiency are to be monitored by measurement of in vivo coagulation activation, e.g. by D-dimer-antigen measurement. Especially with the use of the new oral anticoagulants such a saver anticoagulant therapy - as far as possible from bleeding risk - could open up new indications, which so far are not used because of safety reasons. More patients at risk could be prevented from thromboembolic events. The proposed concept is based on pathophysiological considerations and own clinical experience. It should be evaluated for efficiency in clinical studies.

Impact of time to therapy and presence of collaterals on the efficacy of FX06 in acute ST elevation myocardial infarction: a substudy of the F.I.R.E., the Efficacy of FX06 in the prevention of myocardial reperfusion injury trial.

AIMS: To determine whether the efficacy of FX06 was dependent upon the timing of reperfusion therapy or the presence of collaterals in the Efficacy of FX06 in the prevention of myocardial reperfusion injury (F.I.R.E.) trial. METHODS AND RESULTS: Two hundred and thirty-four (234) patients presenting with acute ST-segment elevation myocardial infarction were randomised to FX06 or matching placebo given as an intravenous bolus at reperfusion. Infarct size was assessed at 5-7 days and four months after myocardial infarction by cardiac magnetic resonance imaging determined total late enhancement and necrotic core zone. Patients were stratified according to presentation status (time-to-therapy <3 hours, n=108; time-to-therapy=3-6 hours, n=115) and presence of collaterals (yes, 46; no, 177). There were no statistically significant differences between groups at day 5-7. At four months, we observed statistically significant reductions of both measures of infarct size (0.3% vs. 2.4%, p=0.038; 8.0% vs. 16.0%, p=0.032) in the group given FX06 and presenting early. There was also a statistically significant reduction of total late enhancement zone among patients given FX06 with collaterals (7.3% vs. 15.2%, p=0.043). No differences were evident among late presenters or those without collaterals. CONCLUSIONS: FX06 significantly reduced infarct size at four months in the early presenters and in those with collaterals.

HIV is associated with thrombophilia and high D-dimer in children and adolescents.

BACKGROUND AND OBJECTIVE: Atherosclerosis and other cardiovascular diseases associated with thrombosis appear more relevant and anticipated in HIV-infected patients after combination antiretroviral therapy (cART) has reduced AIDS-related diseases and has improved survival. The association between viral replication and coagulation abnormalities in a cohort of HIV-infected children and adolescents was investigated here. METHODS: Protein S, protein C anticoagulant and antithrombin activity, together with fibrinogen, D-dimer, high-sensitive C-reactive protein and homocysteine were assayed in a cross-sectional study among a cohort of HIV-infected children and adolescents. Results in patients with high viral load (HVL, HIV-RNA > 1000 copies/ml) were compared with those in patients with a lower replication (LVL), adjusting for other demographic, clinical and therapeutic covariates. RESULTS: Eighty-eight patients (mean age 13.5 years, CD4 30%, 72% with LVL) were enrolled. A prevalence of protein S and protein C deficiency of 51 and 8% was, respectively, found. HVL group compared to LVL showed a significant reduction of protein S, protein C and antithrombin activities, and an increase of D-dimer levels. The independent association of HVL with decreased protein S activity (-11.2%, P = 0.04) and increased D-dimer levels (+0.13 microg/ml, P = 0.004) was confirmed in the multivariate model. CONCLUSIONS: HIV-infected children and adolescents present high prevalence of thrombophilic abnormalities. The multivariate model confirmed that high viral replication is independently associated with decrease of protein S and increase of D-dimer, suggesting the advantage of suppressive therapy on coagulation homeostasis and the opportunity of an active control of cardiovascular risk factors starting at a younger age.

Effect of intravenous FX06 as an adjunct to primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction results of the F.I.R.E. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury) trial.

OBJECTIVES: The purpose of this study was to investigate whether FX06 would limit infarct size when given as an adjunct to percutaneous coronary intervention. BACKGROUND: FX06, a naturally occurring peptide derived from human fibrin, has been shown to reduce myocardial infarct size in animal models by mitigating reperfusion injury. METHODS: In all, 234 patients presenting with acute ST-segment elevation myocardial infarction were randomized in 26 centers. FX06 or matching placebo was given as intravenous bolus at reperfusion. Infarct size was assessed 5 days after myocardial infarction by late gadolinium enhanced cardiac magnetic resonance imaging. Secondary outcomes included size of necrotic core zone and microvascular obstruction at 5 days, infarct size at 4 months, left ventricular function, troponin I levels, and safety. RESULTS: There were no baseline differences between groups. On day 5, there was no significant difference in total late gadolinium enhanced zone in the FX06 group compared with placebo (reduction by 21%; p = 0.207). The necrotic core zone, however, was significantly reduced by 58% (median 1.77 g [interquartile range 0.0, 9.09 g] vs. 4.20 g [interquartile range 0.3, 9.93 g]; p < 0.025). There were no significant differences in troponin I levels (at 48 h, -17% in the FX06 group). After 4 months, there were no longer significant differences in scar size. There were numerically fewer serious cardiac events in the FX06-treated group, and no differences in adverse events. CONCLUSIONS: In this proof-of-concept trial, FX06 reduced the necrotic core zone as one measure of infarct size on magnetic resonance imaging, while total late enhancement was not significantly different between groups. The drug appears safe and well tolerated. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury [F.I.R.E.]; NCT00326976).