Natural Coagulation Inhibitors Research Articles

Innovative approaches to assessing risk factors, diagnostics and treatment of neonatal thrombosis

Compared to children of other ages, neonates especially seriously ill and premature subjects comprise a high thrombotic risk group. A decline in the incidence of neonatal thrombosis may be accounted for by improved treatment of severe conditions in newborns and increased survival of premature infants. Neonatal and adult hemostasis exhibit distinct physiological features: difference in concentration, synthesis rate of blood coagulation factors, metabolic rate, thrombin and plasmin levels. At the same time, neonatal threshold values for natural blood coagulation inhibitors (protein C, protein S, antithrombin, heparin cofactor II) and vitamin K-dependent coagulation factors (FII, FVII, FIX, FX) are quite low, whereas that of FVIII and von Willebrand factor exceeds those found in adults. Thus, newborns have lower plasma fibrinolytic activity. The main risk factors for developing thrombotic complications are as follows: central venous catheters, altered body fluid volume, liver disease, as well as sepsis and inflammatory processes particularly COVID-19. The significance of congenital and acquired maternal and neonatal thrombophilia may pose an additional risk factor for thrombotic complications. Low-molecular weight heparins are the first-choice drugs in treatment and prevention of neonatal thrombosis.

Ramadan intermittent fasting is associated with improved anticoagulant activity among healthy people: a case–control study

Data on the pathophysiological mechanisms of hemostatic alterations in the thrombotic events that occur during Ramadan intermittent fasting (RIF), particularly in the natural coagulation inhibitors, are very limited. Thus, our objective was to evaluate the effect of RIF on the natural anticoagulants level, antithrombin, protein C, and total and free protein S (PS) in healthy participants. Participants were divided into two groups. Group I consisted of 29 healthy fasting participants whose blood samples were taken after 20 days of fasting. Group II included 40 healthy non-fasting participants whose blood samples were taken 2–4 weeks before the month of Ramadan. Coagulation screening tests including prothrombin time (PT), activated partial thromboplastin time (APTT) and plasma fibrinogen level, natural anticoagulants; antithrombin, protein C, free and total PS and C4 binding protein (C4BP) levels were evaluated in the two groups. High levels of total and free PS without change in antithrombin, protein C, and C4BP levels were noted in the fasting group as compared with non-fasting ones (p < 0.05). PT and APTT showed no difference between the two groups. However, the fibrinogen level was higher in the fasting group. In conclusion, RIF was found to be associated with improved anticoagulant activity in healthy participants, which may provide temporal physiological protection against the development of thrombosis in healthy fasting people.

The Hemostatic System in Newborns and the Risk of Neonatal Thrombosis.

Newborns are the most vulnerable patients for thrombosis development among all children, with critically ill and premature infants being in the highest risk group. The upward trend in the rate of neonatal thrombosis could be attributed to progress in the treatment of severe neonatal conditions and the increased survival in premature babies. There are physiological differences in the hemostatic system between neonates and adults. Neonates differ in concentrations and rate of synthesis of most coagulation factors, turnover rates, the ability to regulate thrombin and plasmin, and in greater variability compared to adults. Natural inhibitors of coagulation (protein C, protein S, antithrombin, heparin cofactor II) and vitamin K-dependent coagulation factors (factors II, VII, IX, X) are low, but factor VIII and von Willebrand factor are elevated. Newborns have decreased fibrinolytic activity. In the healthy neonate, the balance is maintained but appears more easily converted into thrombosis. Neonatal hemostasis has less buffer capacity, and almost 95% of thrombosis is provoked. Different triggering risk factors are responsible for thrombosis in neonates, but the most important risk factors for thrombosis are central catheters, fluid fluctuations, liver dysfunction, and septic and inflammatory conditions. Low-molecular-weight heparins are the agents of choice for anticoagulation.

Today's view of hereditary thrombophilia.

Venous thromboembolism (VTE) is still a serious medical problem with the non-decreasing incidence of new cases despite prophylaxis in risky situations. It is a multifactorial disease, in which the hereditary component is also significantly involved. The aim of the current research is to search for new polymorphisms that are involved in thrombogenesis in addition to classical thrombophilia (deficiency of natural coagulation inhibitors and FVL and FII prothrombin mutations). The article provides an overview of the results of already performed genome-wide association studies of VTE and their use for the calculation of the so-called polygenic risk score, which could be used for individualized prevention of VTE after standardization of the method.

Profile of Perioperative Coagulation in Major Liver Resection for Cancer: A Prospective Observational Study

Background: The liver plays a key role in the complex and dynamic process of blood coagulation. Consequently, after liver resection the equilibrium between procoagulant and anticoagulant activity is often deranged. Major hepatectomies have been associated with excessive intraoperative blood loss, hemodynamic instability, massive fluid shifts, and coagulopathy. Alterations of the coagulation profile are always present post-operatively even in case of normal pre-operative coagulation function. Cumulative evidence supports the superiority of global coagulation analysis compared with conventional coagulation for clinical decision-making. Aim: The purpose of this study was to assess the perioperative coagulation status of patients undergoing major hepatectomies for primary or metastatic hepatic malignancy. Conventional coagulation tests, plasma levels of coagulation factors, and TGA measurements were used for longitudinal documentation of the coagulation activity. Methods: Patients included in the study were referred for major liver resection which was defined as a resection of three or more liver segments, and were followed up to the 10th post-operative day by serial measurements of conventional coagulation tests, plasma levels of coagulation factors, and thrombin generation assay parameters. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were determined by STA Neoplastin R, and STA-Cephascreen, Fibrinogen by STA-Liquid Fib, D-dimer STA Liatest D-DI Plus, all from Diagnostica Stago, France. Coagulation factor activity for FII, FV, FVII, FVIII, FIX, FX, was measured by clotting assay using coagulation factor deficient plasma, vWFAg , and vWFAc by vWFAg and Innovance vWFAc, from Siemens Healthcare Diagnostics, Germany. Thrombin generation (TG) was assessed in samples of PPP with the TF 5 pM PPP-Reagent on Calibrated Automated Thrombogram (Stago, France). Results: Changes over time for FII, FV, FVII and FX were statistically significant (p <0.05). Factor VIII level was above normal values at baseline. A steady rise was observed for fibrinogen, FVIII, and vWF antigen throughout the study period, but only vWF antigen exhibited statistically significant changes over time. Levels of coagulation inhibitors, AT, PC and PS, decreased significantly during the first postoperative day and then increased reaching baseline values by POD5 for protein C and S, but AT, remained low by POD10. INR increased after surgery, reaching a peak on the first post-operative day and decreasing toward baseline levels from then on (p <0.001). The aPTT remained within normal range throughout the study period (Table 1). TG conducted at baseline, on POD1, POD5, and POD10 showed elevated of Lag time and time to peak at baseline, whereas the rest thrombin generation parameters were within reference range. ETP decreased significantly over time, reaching lower values by POD5 and sustaining those low values by POD10. Peak height fluctuated in a similar manner, but changes over time did not bear any statistical significance. Lag-time, which was prolonged at baseline, exhibited a steady rise throughout the study period, bearing borderline statistical significance (Table 2) . A statistically significant positive correlation was detected between AT and time to Peak (ttPeak) at baseline, however any other significant difference between coagulation factors, natural coagulation inhibitors, and TGA parameters was observed. Conclusion: This study shows that patients with hepatic malignancy have systematic endothelial activation and hyper-coagulability as indicated by increased FVIII levels and lag time prolongation in thrombin generation. These patients are in a hyper-coagulable state in the early post-operative period, as shown by increased vWF, FVIII, D-dimer, fibrinogen and decreased levels of natural coagulation inhibitors AT, PC, and PS. Measurements of INR, PT, aPTT are not useful in this setting and could be misleading. Global coagulation analysis may be more appropriate for clinical guidance. To the best of our knowledge this is the first report in literature documenting the pre-existing coagulation disturbances in patients with hepatic carcinoma and their impact on the coagulation status after major hepatectomy. However, the clinical implications of our findings deserve further investigation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Mortality and Deep Vein Thrombosis in the Gamma Variant of Covid 19 and Lung Injury.

The SARS-CoV-2 disease predisposes infected individuals to thrombosis, the underlying mechanisms of which are not fully understood. The balance between pro-coagulant factors and natural coagulation inhibitors in critically ill patients with Covid-19 is fundamental to the prevention and treatment of complications. The aim of the present study was to investigate the pulmonary injury patterns in Covid-19 having higher mortality in the presence of deep vein thrombosis in comparison to patients without venous thrombosis and determine the Gamma variant. A retrospective study was conducted involving the evaluation of 200 medical records of patients with Covid-19 and a clinical suspicion of deep vein thrombosis (DVT) at the intensive care unit of a public hospital. The sample was divided into two groups of patients were formed - those positive and those negative for DVT. Statistical analysis involved the use of Fisher's exact test, the paired t-test and chi-square test. Patients with DVT had more severe lung injuries (greater than 70%) compared to those without DVT (p = 0.003). Lesions affecting 50% to 70% of the lung area occurred in little more half of the group with DVT and just under half in the group without DVT (p = 0.5). Pulmonary lesions affecting less than 50% of the lung occurred more in patients without DVT (p = 0.0001). The Gamma variant increased prevalence of the both DVT and mortality (p=0.0001). Deep vein thrombosis is an aggravating factor of mortality in patients with SARS-CoV-2, and the Gamma variant is an aggravating factor of both thrombotic events and mortality.

Inflammatory Bowel Disease Presenting With Retiform Purpura.

A 7-year-old girl with sickle cell trait was admitted with inability to bear weight and a painful rash. Examination demonstrated retiform purpura (RP) of the right leg (Fig. 1A) with tenderness. The lesions had worsened despite treatment with cephalexin. Family history was unremarkable. There was no other skin involvement, history of fevers, or abnormalities on exam. Bloodwork was notable for microcytic anemia, elevated ESR, mildly elevated transaminases, and normal INR, albumin, and creatine kinase. MRI showed no muscle, bone, or joint involvement. Sequential cutaneous punch biopsies showed superficial and deep mixed perivascular and interstitial dermatitis without thromboses or leukocytoclastic vasculitis. Direct immunofluorescence findings were nonspecific. Hematologic evaluation included normal protein C and S levels, and mildly elevated d-dimer. Rheumatologic and infectious disease evaluations were also unremarkable. Over the following weeks new purpuric patches appeared, with some developing central duskiness and necrosis (Fig. 1B,C). After being noted to have mild colitic symptoms (PUCAI 25), elevated fecal calprotectin, persistently elevated transaminases, and a positive antinuclear antibody she underwent endoscopy, colonoscopy, and liver biopsy leading to the diagnoses of ulcerative colitis (Fig. 2) and autoimmune hepatitis. Treatment with systemic steroids improved her pain and transaminases, but the rash continued to evolve over the following 3 months developing a central necrotic eschar with surrounding ulceration to the subcutaneous tissue that slowly healed with supportive wound care (Fig. 1C–E).FIGURE 1.: Anterior views of the right thigh on presentation (A), 1 week later (B), 2 weeks later (C), 1 month later (D), 2 months later (E), and 3 months later (F). Purpura (A,B) were not palpable as are observed in cutaneous small-vessel vasculitis. Note the absence of marked purulence (D, E) or cribriform scarring (F) which are observed in pyoderma gangrenosum.FIGURE 2.: Colonoscopy showed gross pancolitis (A) with erythema, edema, friability and microhemorrhages. Histopathologic findings (B) included chronic active colitis with cryptitis (arrow) and abnormal crypt branching (arrowheads) but no granulomata.RP presents as branching purpuric patches and develops when dermal and subcutaneous blood vessels are compromised by vessel wall damage or lumen occlusion causing pain, necrosis, and ulceration (1). Underlying processes include those that damage the vessel wall such as small- or medium-vessel vasculitides, angioinvasive infections, and depositional diseases. RP also results from vessel lumen occlusion due to thrombosis from hypercoagulable states, platelet disorders, and red blood cell occlusion, as well as embolic processes (1,2). Clinically, it can resemble cutaneous small-vessel vasculitis (CSVV) or pyoderma gangrenosum but is differentiated by the lack of palpable purpura or marked purulence, respectively (3,4). Histologically, the vascular origin of RP is deeper than CSVV and it lacks the neutrophilic infiltrate characteristic of pyoderma gangrenosum (3–5). Treatment should address the underlying etiology and include supportive wound care (6). Here, the vaso-occlusive process RP was the presenting feature in a patient with unrecognized inflammatory bowel disease. This may reflect the incompletely understood association between coagulation and inflammation in inflammatory bowel disease that is posited to result from the interplay between a hyperactive coagulation system, decreases in natural coagulation inhibitors, abnormal fibrinolysis, endothelial dysfunction, chronically activated platelets, and systemic inflammation (2,7,8).

Protein S and protein C in preeclamptic pregnant women

Background and purpose: Deficits of protein C and protein S are associated with an increased incidence of thrombotic disorders. The aim of the present study was to determine the levels of the mentioned natural coagulation inhibitors in women with preeclampsia and in a 6-months followup period after delivery.Materials and methods: This case-control clinical study included 55 pregnant women (cases) with preeclampsia and 50 healthy normotensive pregnant women (controls) in tertiary perinatal centre. Protein C levels were determined photometrically using a chromogen substrate, and protein S levels were determined using the clot method and optic detection.Results: There were no significant differences in protein C and protein S levels between women with preeclampsia and healthy pregnant women; however, six months after delivery protein S levels were significantly lower in women with preeclampsia as compared to healthy peers, whereas protein C levels did not differ significantly.Conclusion: Possible long-term cardiovascular morbidity should be assessed in preeclampsia women.

The risk of arterial thrombosis in carriers of natural coagulation inhibitors: a prospective family cohort study

BackgroundWhether the carriership of inherited antithrombin (AT), protein C (PC), and protein S (PS) deficiency increases the risk of arterial thromboembolic events (ATE) is controversial. This information has the potential to inform the management of family members of probands with inherited deficiency of natural anticoagulants.Patients/methodsWe conducted a large prospective family cohort study in 640 subjects (of whom 341 carriers and 299 non-carriers) belonging to 86 families with inherited deficiency of AT, PC, or PS.ResultsA total of 4240 and 3810 patient-years were available for carriers and non-carriers, respectively. Risk factors for atherosclerosis were similarly distributed in the two groups. Of the 26 ATE that were recorded, 19 occurred in carriers (5.6%), as compared to 7 in non-carriers (2.3%) [p = 0.07]. After adjusting for confounders, the hazard ratio (HR) for ATE was 4.9 (95% CI 1.5–16.3) in carriers as compared to non-carriers.ConclusionsAmong family members of probands with an inherited deficiency of natural anticoagulants, carriers exhibit a risk of ATE that is almost five times higher than in non-carriers.

Elevated levels of tissue factor pathway inhibitor in patients with mild to moderate bleeding tendency

AbstractHigh levels of tissue factor pathway inhibitor (TFPI), caused by a longer TFPIα half-life after binding to a factor V splice variant and variants in the F5 gene, were recently identified in 2 families with an as-yet-unexplained bleeding tendency. This study aimed to investigate free TFPIα in a well-characterized cohort of 620 patients with mild to moderate bleeding tendencies and its association to genetic alterations in the F5 gene. TFPIα levels were higher in patients with bleeding compared with healthy controls (median [interquartile range], 8.2 [5.5-11.7] vs 7.8 [4.3-11.1]; P = .026). A higher proportion of patients had free TFPIα levels more than or equal to the 95th percentile compared with healthy controls (odds ratio [OR] [95% confidence interval (CI)], 2.82 [0.98-8.13]). This was pronounced in the subgroup of patients in whom no bleeding disorder could be identified (bleeding of unknown cause [BUC; n = 420]; OR [95% CI], 3.03 [1.02-8.98]) and in platelet function defects (PFDs) (n = 121; OR [95% CI], 3.47 [1.09-11.08]). An increase in free TFPIα was associated with a mild delay in thrombin generation (prolonged lag time and time to peak), but not with alterations in routinely used global clotting tests. We could neither identify new or known genetic variations in the F5 gene that are associated with free TFPIα levels, nor an influence of the single-nucleotide variant rs10800453 on free TFPIα levels in our patient cohort. An imbalance of natural coagulation inhibitors such as TFPIα could be an underlying cause or contributor for unexplained bleeding, which is most probably multifactorial in a majority of patients.

Biomarkers of Hypercoagulability and Endothelial Cell Activation in Patients with Severe COVID-19 Admitted at the Intensive Care Unit. the Roadmap-COVID-19 Prospective Observational Study

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) characterized by acute pneumonia which may progress to respiratory failure and life-threatening complications, including acute respiratory distress syndrome (ARDS) and multisystem organ failure with fatal outcome. COVID-19 should be regarded as a systemic disease involving multiple systems. COVID-19 is associated with excessive inflammation, platelet activation, endothelial dysfunction, blood coagulation activation and fibrin formation. The development of a screening algorithm for the evaluation of endothelial and blood coagulation activation is an urgent need for the optimisation of the management of the patients with severe COVID-19. To this aim biomarkers of endothelial cell activation and hypercoagulability have central placeAim: The prospective observational monocentric cohort study ROADMAP-COVID-19 study aimed to evaluate the biomarkers of hypercoagulability and endothelial cell activation which they could be used in the development of a screening algorithm in patients with COVID-19Methods: The ROADMAP-COVID-19 study enrolled 90 consecutive patients hospitalized at Tenon University Hospital (AP-HP, Paris) between March 18th and April 30th, 2020 with confirmed SARS-CoV-2 infection admitted to the ICU with clinically deteriorated severe COVID-19 (ICU- group). Patients were assessed upon the first day to the ICU admission. The control group consisted 30 healthy individuals (C-group). All patients and controls were evaluated for, clotting times (PT and aPTT), fibrinogen, D-Dimers, antithrombin (AT), protein C (PC) and protein S (Ps) activity, clotting factors V (FV), VIII (FVIII) and XII (FXII), high molecular weight kininogen (HK), von Willebrand factor (FvW), thrombin generation assay (TG) using TF 20 pM-PPP-Reagent® (Thrombogram-Thrombinoscope from Stago), fibrin monomers (FM), free TFPI and TF activity, thrombomodulin activity (TM), TF expressing microparticles (the ratio TF/TFPI was also calculated) and Heparanase. The IL-6 levels were also measured. All patients hospitalized in conventional medical department or in ICU routinely received thromboprophylaxis with body weight adapted enoxaparin. The ratio of the mean values of each studied biomarker in the ICU and the C-group was calculated. Biomarkers were classified in four clusters (Decrease, Stable, Slight Increase, Moderate Increase and High Increase).Results :The ICU-group consisted of 102 patients; 87% of these patients were admitted to the ICU directly from the emergency department. Males were 76 out of 102 patients. Age ranged from 30 to 93 years in the W-group. The changes of the biomarkers in patients with COVID-19 admitted at the ICU as compared to healthy individuals with are shown in Table 1. The ICU patients with COVID-19 were characterized by marked increase of IL-6 followed by increase of heparanase and D-dimers. The PPL-ct showed the most important decrease. Patients showed a significant decrease in FXII levels which was associated with a moderate increase of kininogen levels. The levels of the natural coagulation inhibitors as well as the clotting times (PT and aPTT) did not significantly modify in patients as compared to the controls. The rate of the propagation phase of thrombin generation (MRI) and the Peak of thrombin were significantly decrease and the lag-time was prolonged reflecting the antithrombotic effect of treatment with LMWH. Heparanse, free TFPI, and TM showed moderate or high increase. The decreased Ratio of TF/TFPI indicated that the free TFPI release dominated over the release of soluble TF activity.Conclusion: Patients with severe COVID-19 requiring ICU admission showed inhaled inflammatory reaction, hyperocoagulability and endothelial cell activation whereas platelet activation appeared to be secondary. Among the studied biomarkers the PPL-ct D-dimers and heparanase followed by TFPI, FvW, FM and TM levels appear to be mandatory for hypercoagulability of cellular origin. Interestingly patients with severe COVID-19 showed consumption of FXII indicating intrinsic clotting pathway activation and high levels of HK which also indicates endothelial cell activation. The clinical relevance of these biomarkers for early detection of hypercoagulability of cellular origin in patients with COVID-19 is being evaluated in prospective study.DisclosuresNo relevant conflicts of interest to declare.

Differences in the Coagulation Profile in Women with Mild and Severe Preeclampsia

Introduction:Different coagulations abnormalities have been referred in women with early oncet preeclampsia (EOP), but there are only few studies comparing those changes regarding to the severity of the disease. Aim:In this study we aimed to investigate the differences between the coagulation profile in women with mild and severe preeclampsia. Methods:This is an observational retrospective case-control study. Plasma samples were collected from 84 women divided into three groups, the healthy pregnant (HP) group (n=35), the mild preeclampsia (MP) group (n=34) and the severe preeclampsia (SP) group (n=15). The study population general characteristics are shown in Table 1. We studied the following biomarkers of hypercoagulability and endothelial cell activation: Tissue factor activity (TFa), Procoagulant phospholipid activity (PPL), Protein S, D-Dimers, Antithrombin, thrombomodulin, TFPI levels. All women were assessed with classic coagulation tests (aPTT and PT) fibrinogen levels and hemogram. Statistical analysis was performed using the PASW Statistics 17.0.2 (SPSS Inc.) for Windows. Results:Women with preeclampsia - mild or severe- showed significant increase of TFPI, TFa and TMa levels as compared to healthy pregnant women. No significant difference of TFPI, TFa was observed between MP and SP groups. In contrast, TMa levels were significantly increased in SP as compared to MP group. The ratio TFa/TFPI was also lower in SP as compared to MP-group. Women in MP or SP group had similarly shorter PPL clotting time as compared to HP group. D-dimer levels were increased in women with preeclampsia as compared to the HP group. D-Dimer levels were significantly higher in SP as compared to MP group. The levels of free PS activity in HP as well as MP and SP groups were lower than normal range in non-pregnant women and the value in MP was significantly lower than that of the HP or SP. Fibrinogen levels were not significantly different in the three studied groups of pregnant women. Prothrombin time was found to be increased in cases as compared to that in the controls. The mean value of prothrombin time in mild preeclampsia was 13.24±0.80 seconds and in severe preeclampsia it was seconds 14.77±0.96 and in pregnant controls 12.23±0.59 seconds (p&amp;lt;0.05 and p&amp;lt;0.001 respectively). The mean prothrombin time was found to increase with increasing severity of disease (p&amp;lt;0.001). The mean activated partial thromboplastin time were increased in mild preeclampsia and was 32.64±1.83 seconds and in severe preeclampsia it was 35.59±1.53 seconds and in pregnant controls 29.53±1.62 seconds (p&amp;lt;0.001). The activated partial thromboplastin time was found to increase with increasing severity of disease (p&amp;lt;0.001). The antithrombin III decreased in severe SP and MP or compared to pregnant controls (76.33±4.32 and 88.06±9.68 versus 95.40±0.36 respectively; p&amp;lt;0.001). This decrease is more pronounced in SP compared to MP (p&amp;lt;0.001). Conclusions:Preeclampsia is associated with endothelial cell activation as documented by the increase of TFa, soluble TM levels and TFPI levels in plasma. Release of soluble thrombomoduline and TFPI rather than TFa by endothelial cells appear to be related with degree of preeclampsia severity. Women with preeclampsia showed marked decrease of PPL clotting time indicating enhanced platelet activation that was independent of the severity of preeclampsia. In contrast, women with severe preeclampsia showed signs of enhanced hypercoagulability documented by the increase of D-dimer levels consumption of natural coagulation inhibitors and particularly of AT. This phenomenon tended to be reflected on the prolongation of PT and aPTT in women with severe preeclampsia. Disclosures No relevant conflicts of interest to declare.

Imbalance between procoagulant factors and natural coagulation inhibitors contributes to hypercoagulability in the critically ill COVID-19 patient: clinical implications.

Coronavirus Disease-2019 (COVID-19) predisposes patients to thrombosis which underlying mechanisms are still incompletely understood. We sought to investigate the balance between procoagulant factors and natural coagulation inhibitors in the critically ill COVID-19 patient and to evaluate the usefulness of hemostasis parameters to identify patients at risk of venous thromboembolic event (VTE). We conducted an observational study recording VTEs defined as deep vein thrombosis or pulmonary embolism using lower limb ultrasound (92% of the patients), computed tomography pulmonary angiography (6%) and both tests (2%). We developed a comprehensive analysis of hemostasis. Ninety-two consecutive mechanically ventilated COVID-19 patients (age, 62 years [53-69] (median [25th-75th percentiles]); M/F sex ratio, 2.5; body-mass index, 28 kg/m2 [25-32]; past hypertension (52%) and diabetes mellitus (30%)) admitted to the Intensive Care Unit (ICU) from 03/11/2020 to 5/05/2020, were included. When tested, patients were receiving prophylactic (74%) or therapeutic (26%) anticoagulation. Forty patients (43%) were diagnosed with VTE. Patients displayed inflammatory and prothrombotic profile including markedly elevated plasma fibrinogen (7.7 g/L [6.1-8.6]), D-dimer (3,360 ng/mL [1668-7575]), factor V (166 IU/dL [136-195]) and factor VIII activities (294 IU/dL [223-362]). We evidenced significant discrepant protein C anticoagulant and chromogenic activities, combined with slightly decreased protein S activity. Plasma D-dimer >3,300 ng/mL predicted VTE presence with 78% (95%-confidence interval (95% CI), 62-89) sensitivity, 69% (95% CI, 55-81) specificity, 66% (95% CI, 51-79) positive predictive value and 80% (95% CI, 65-90) negative predictive value [area under the ROC curve, 0.779 (95%CI, 0.681-0.859), p=0.0001]. Mechanically ventilated COVID-19 patients present with an imbalance between markedly increased factor V/VIII activity and overwhelmed protein C/S pathway. Plasma D-dimer may be a useful biomarker at the bedside for suspicion of VTE.

Plasma Serotonin is Elevated in Adult Patients with Sudden Sensorineural Hearing Loss.

The roles of thrombophilia and cardiovascular risk factors in sudden sensorineural hearing loss (SSNHL) remain controversial. Cochlear microthrombosis and vasospasm have been hypothesized as possible pathogenic mechanisms of SSNHL. This article investigates the circulating serotonin and homocysteine levels besides thrombophilia screening in patients with idiopathic SSNHL. A total of 133 SSNHL patients and age- and sex-matched controls were investigated (discovery cohort). Measurement included common inherited natural coagulation inhibitors, factor VIII, von Willebrand factor (VWF), antiphospholipid antibodies, homocysteine, and serotonin (whole blood, platelet, and plasma) levels, along with frequent relevant genetic variants. A validation cohort (128 SSNHL patients) was studied for homocysteine and serotonin levels. In the discovery cohort, 58.6% of patients exhibited thrombophilia, of which most had a low to moderate titers of antiphospholipid antibodies and high levels of factor VIII/VWF. Twenty-seven patients (20%) had mild-to-moderate hyperhomocysteinemia or were homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation. Regarding serotonin, SSNHL patients had elevated whole blood levels that remained within the normal range and normal platelet content. However, approximately 90% patients of both cohorts had elevated plasma serotonin. Elevated plasma serotoninemia was accompanied by serotonylation of platelet rhoA protein. This study shows that increased plasma serotonin appears as a biomarker of SSNHL (specificity: ∼96%, sensitivity: ∼90%) and could participate in the pathophysiology of SSNHL.

Venous thromboembolism in inflammatory bowel disease.

Patients with inflammatory bowel disease (IBD) are at an increased risk for venous thromboembolism (VTE). VTE events carry significant morbidity and mortality, and have been associated with worse outcomes in patients with IBD. Studies have suggested that the hypercoagulable nature of the disease stems from a complex interplay of systems that include the coagulation cascade, natural coagulation inhibitors, fibrinolytic system, endothelium, immune system, and platelets. Additionally, clinical factors that increase the likelihood of a VTE event among IBD patients include older age (though some studies suggest younger patients have a higher relative risk of VTE, the incidence in this population is much lower as compared to the older IBD patient population), pregnancy, active disease, more extensive disease, hospitalization, the use of certain medications such as corticosteroids or tofacitinb, and IBD-related surgeries. Despite the increased risk of VTE among IBD patients and the safety of pharmacologic prophylaxis, adherence rates among hospitalized IBD patients appear to be low. Furthermore, recent data suggests that there is a population of high risk IBD patients who may benefit from post-discharge prophylaxis. This review will provide an overview of patient specific factors that affect VTE risk, elucidate reasons for lack of VTE prophylaxis among hospitalized IBD patients, and focus on recent data describing those at highest risk for recurrent VTE post-hospital discharge.

Low levels of coagulation inhibitors: a high-risk thrombotic factor in thalassemic patients

Background and aimThe β-thalassemia major (β-TM) is defined as a hereditary red blood cell (RBC)- related disease. Thrombotic events are associated with thalassemia in adult patients. Thus, the present investigation was aimed to examine some hemostatic parameters, including anti thrombin- III (AT-III), protein-C (PRC) and protein-S (PRS) in β-TM patients. MethodsThirty B-TM patients who referred for routine follow-up admission to the thalassemia clinic of Kerman Special Disease Center alongside with 30 healthy subjects were selected and enrolled in the present study. Further registration, the peripheral blood specimens were collected after 3 weeks of last transfusion and then the plasma concentrations of AT-III, PRC and PRS were measured in them. ResultsWe have observed that the concentrations of natural coagulation inhibitors (PRC and PRS) were significantly attenuated in β-TM patients (P < 0.05), while the plasma level of AT-III was not remarkably differed in β-TM patients in compare to healthy subjects. ConclusionAccording to the findings of present work, significant changes in the PRC, PRS and AT-III which could be observed in multi transfused β-TM patients may attribute as critical risk factors for the development of upcoming thromboembolic events in their future life.

Bajos niveles de inhibidores de la coagulación: un factor de alto riesgo trombogénico en pacientes talasémicos

Background and aimThe β-thalassemia major (β-TM) is defined as a hereditary red blood cell-related disease. Thrombotic events are associated with thalassemia in adult patients. Thus, the present investigation was aimed to examine some hemostatic parameters, including anti thrombin-III (AT-III), protein-C (PRC) and protein-S (PRS) in β-TM patients. MethodsThirty B-TM patients who referred for routine follow-up admission to the thalassemia clinic of Kerman Special Disease Center alongside with 30 healthy subjects were selected and enrolled in the present study. Further registration, the peripheral blood specimens were collected after 3 weeks of last transfusion and then the plasma concentrations of AT-III, PRC and PRS were measured in them. ResultsWe have observed that the concentrations of natural coagulation inhibitors (PRC and PRS) were significantly attenuated in β-TM patients (P<0.05), while the plasma level of AT-III was not remarkably differed in β-TM patients in compare to healthy subjects. ConclusionAccording to the findings of present work, significant changes in the PRC, PRS and AT-III which could be observed in multi transfused β-TM patients may attribute as critical risk factors for the development of upcoming thromboembolic events in their future life.

Assessment of The Level of Protein C in Children with Nephrotic Syndrome

Background: thromboembolic events remain one of the most serious complications in patients with nephrotic syndrome and this thrombotic tendency could be related to deficiency in natural coagulation inhibitors. Objective: the aim of our study was to estimate P-C quantity &quality in the blood of nephrotic patients for the possible role that it might play in the pathogenesis of thromboembolic complications in these patients & trial to find correlations between P-C & some hemostatic parameters. Patient and Methods: this study was carried out on 60 children (age: 3-13years) were diagnosed as nephrotic patients. They were classified as follow: G1- comprised of 20 cases in relapse, G2- comprised of 20 cases in remission (the same cases of relapse), G3- comprised of 20 healthy children as control group. Results: Our study showed very high significant increase in P-C, both in activity and concentration in relapse but in remission its level decreased towards the normal level but still slightly increased and this increase is statistically nonsignificant. As regard serum albumin and serum total protein, the both were very highly significantly increased in relapse and remission as compared to the control. As regard PT and PTT were found to be highly significant decreased in relapse as compared to the control group. Conclusion: from the foregoing we can concluded that, Increase level of P-C in N.S. denoted that it has no role in thromboembolic complications and Increase level of P-C in N.S may afford some protection against the thrombotic diathesis by counteracting hypercoagulability state.

Laboratory Diagnostics in Thrombophilia.

A thrombophilic disorder is a hereditary or acquired condition that increases the risk of thrombosis. The most common hereditary thrombophilias that predispose to venous thrombosis in the Caucasian population are the heterozygous forms of the factor V Leiden and prothrombin G20210A mutation that are generally detected by direct DNA genotyping. Immunologic antigen assays and chromogenic or clot-based activity assays are used to identify deficiencies in the natural coagulation inhibitors antithrombin, protein C and protein S. Because pre-analytical errors and acquired causes of low antithrombin, protein C or protein S levels are considerably more common than hereditary deficiencies, all potential conditions that may lower activity levels of the natural coagulation inhibitors (e.g. concomitant liver disease, pregnancy, anticoagulant therapy) must be considered and excluded before the diagnosis of an inhibitor deficiency can be made. To avoid misclassification, the diagnosis should not be made based on a single abnormal test result. Thus, repetitive testing when the patient is not on anticoagulant therapy is mandatory to confirm the diagnosis. Screening for antiphospholipid syndrome (APS) comprises testing for lupus anticoagulants (LAs) and the presence of IgG or IgM antibodies directed against phospholipids and phospholipid-binding proteins such as β-2-glycoprotein-I. A combination of clot-based assays has been recommended to demonstrate LA activity, whereas solid-phase immunoassays allow the detection of anti-cardiolipin and anti-β-2-glycoprotein-I antibodies. The diagnosis of APS requires the persistence of antiphospholipid antibodies for at least 12 weeks together with thrombotic and/or obstetric features of APS.

Use of DOAC Stop for elimination of anticoagulants in the thrombin generation assay

Calibrated automated thrombography (CAT) is useful in monitoring the anticoagulant status of patients treated with direct oral anticoagulants (DOACs). This as well as other applications of the CAT are hampered by the wide inter-individual variation, making the diagnosis of the anticoagulant status of a patient on DOAC difficult when using normal pooled plasma as a reference. With dabigatran, the CAT is further hampered, as this direct thrombin inhibitor also inhibits the calibrator that is used in CAT. In this study we examined the added value of the universal DOAC adsorbent DOAC Stop in CAT. For this, we used normal pooled plasma spiked with apixaban, dabigatran, edoxaban or rivaroxaban, and performed CAT with 5 pM tissue factor. DOAC Stop effectively removed DOACs from plasma, leaving the DOAC Stop-treated plasma slightly more procoagulant compared to sham treated, non-anticoagulated plasma. Examining levels of natural coagulation inhibitors revealed a slight reduction in tissue factor pathway inhibitor upon DOAC Stop treatment. When DOAC Stop-treated plasma was used in the calibrator wells, normal unaffected calibration curves were observed, even when dabigatran was present. In conclusion, DOAC Stop can be used to abolish dabigatran influences of anticoagulated plasma when used in the calibrator wells. Also, the anticoagulant status of a DOAC treated patient can be diagnosed simply by comparing untreated plasma with the same plasma sample treated with DOAC Stop. Using this approach, a minor DOAC-independent increase in CAT response in the DOAC Stop-treated sample should be taken into account.