UNASSIGNED: Elevated ambient pollution exposure is potentially linked to thromboembolism. However, the mechanisms by which particulate matter (PM) interferes with the balance of hemostatic system remain unclear. This study investigates PM-mediated hemostatic changes in individuals across unique seasonal variations of ambient pollution.
UNASSIGNED: This prospective study was conducted between February and July 2020 during alterations in ambient pollution in Chiang Mai, Thailand. Blood tests from 30 healthy subjects were assessed at four-week intervals, four times in total. Various coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor (vWF), platelet count, and platelet functions, were evaluated. A mixed-effects model was used to analyze the impact of high PM2.5 and PM10 on hemostatic parameters.
UNASSIGNED: Thirty male subjects with mean age of 38.9 ± 8.2 years, were included. High levels of PM2.5 and PM10 were significantly associated with PT shortening, with no such effect observed in aPTT. PM2.5 and PM10 values also positively correlated with vWF function, while vWF antigen levels remained unchanged. Soluble P-selectin showed a strong positive association with PM2.5 and PM10 levels. Platelet function analysis revealed no correlation with PM values.
UNASSIGNED: Short-term exposure to elevated PM2.5 and PM10 concentrations was linked to shortened PT and enhanced vWF function in healthy individuals. Exploring the impact of these changes on clinically relevant thrombosis is crucial. Additional studies on the pathogenesis of pollution-related thrombosis are warranted for maintaining good health.

UNASSIGNED: Viscoelastic assays have widely been used for evaluating coagulopathies but lack the addition of shear stress important to in vivo clot formation. Stasys technology subjects whole blood to shear forces over factor-coated surfaces. Microclot formation is analyzed to determine clot area (CA) and platelet contractile forces (PCFs). We hypothesize the CA and PCF from this novel assay will provide information that correlates with trauma-induced coagulopathy and transfusion requirements.
UNASSIGNED: Blood samples were collected on adult trauma patients from a single-institution prospective cohort study of high-level activations. Patient and injury characteristics, transfusion data, and outcomes were collected. Thromboelastography, coagulation studies, and Stasys assays were run on paired samples collected at admission. Stasys CA and PCFs were quantified as area under the curve calculations and maximum values. Normal ranges for Stasys assays were determined using healthy donors. Data were compared using Kruskal-Wallis tests and simple linear regression.
UNASSIGNED: From March 2021 to January 2023, 108 samples were obtained. Median age was 37.5 (IQR 27.5-52) years; patients were 77% male. 71% suffered blunt trauma, 26% had an Injury Severity Score of ≥25. An elevated international normalized ratio significantly correlated with decreased cumulative PCF (p=0.05), maximum PCF (p=0.05) and CA (p=0.02). Lower cumulative PCF significantly correlated with transfusion of any products at 6 and 24 hours (p=0.04 and p=0.05) as well as packed red blood cells (pRBCs) at 6 and 24 hours (p=0.04 and p=0.03). A decreased maximum PCF showed significant correlation with receiving any transfusion at 6 (p=0.04) and 24 hours (p=0.02) as well as transfusion of pRBCs, fresh frozen plasma, and platelets in the first 6 hours (p=0.03, p=0.03, p=0.03, respectively).
UNASSIGNED: Assessing coagulopathy in real time remains challenging in trauma patients. In this pilot study, we demonstrated that microfluidic approaches incorporating shear stress could predict transfusion requirements at time of admission as well as requirements in the first 24 hours.
UNASSIGNED: Level II.

Coagulation disorders in critically ill patients presenting with bleeding can be multicausal. The drugs applied can interfere and impair the coagulation cascade. Point-of-care (POC) coagulation assays may resolve difficult therapeutic situations in critical illness. We report on a 73-year-old critically ill male patient with massive hematuria after bladder lithotripsy. The patient was on low molecular weight heparin therapy due to recent pulmonary embolism. He was subjected to repeated surgical hemostasis which was ineffective despite massive transfusion protocol and normal standard coagulation profile. Additional POC coagulation assays were obtained and were indicative of platelet dysfunction. We revised his medical therapy and suspected the possible drug influence on platelet aggregation. After discontinuation of target drug, platelet aggregation increased whereas hematuria stopped. Coagulation disorders in intensive care unit patients are often multifactorial. Standard laboratory tests are unreliable in complex refractory bleeding and may result in inappropriate therapeutic decisions. Stepwise approach with assessment of clinical parameters, present therapy, and a combination of POC coagulation tests is the key to optimal therapeutic management.

Thromboembolism, a global leading cause of mortality, needs accurate risk assessment for effective prophylaxis and treatment. Current stratification methods fall short in predicting thrombotic events, emphasizing the need for a deeper understanding of clot properties. Fibrin clot permeability, a crucial parameter in hypercoagulable states, impacts clot structure and resistance to lysis. Current clot permeability measurement limitations propel the need for standardized methods. Prior findings underscore the importance of clot permeability in various thrombotic conditions but call for improvements and more precise, repeatable, and standardized methods. Addressing these challenges, our study presents an upgraded, portable, and cost-effective system for measuring blood clot permeability, which utilizes a pressure-based approach that adheres to Darcy\'s law. By enhancing precision and sensitivity in discerning clot characteristics, this innovation provides a valuable tool for assessing thrombotic risk and associated pathological conditions. In this paper, the authors present a device that is able to automatically perform the permeability measurements on plasma or fibrinogen in vitro-induced clots on specific holders (filters). The proposed device has been tailored to distinguish clot permeability, with high precision and sensitivity, between healthy subjects and high cardiovascular-risk patients. The precise measure of clot permeability represents an excellent indicator of thrombotic risk, thus allowing the clinician, also on the basis of other anamnestic and laboratory data, to attribute a risk score to the subject. The proposed instrument was characterized by performing permeability measurements in plasma and purified fibrinogen clots derived from 17 Behcet patients and 15 sex- and age-matched controls. As expected, our results clearly indicate a significant difference in plasma clot permeability in Behcet patients with respect to controls (0.0533 ± 0.0199 d vs. 0.0976 ± 0.0160 d, p < 0.001). This difference was confirmed in the patient\'s vs. control fibrin clots (0.0487 ± 0.0170 d vs. 0.1167 ± 0.0487 d, p < 0.001). In conclusion, our study demonstrates the feasibility, efficacy, portability, and cost-effectiveness of a novel device for measuring clot permeability, allowing healthcare providers to better stratify thrombotic risk and tailor interventions, thereby improving patient outcomes and reducing healthcare costs, which could significantly improve the management of thromboembolic diseases.

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.

BACKGROUND: Hypercoagulability has been documented in cats with cardiac disease. However, hemostatic parameters, including viscoelastic coagulation monitoring (VCM) have not been reported in cats with arterial thromboembolism (ATE).
OBJECTIVE: Compare VCM parameters in cats with acute cardiogenic ATE and in control cats.
METHODS: Sixteen cats with ATE and 30 control cats.
METHODS: Multicenter university-based prospective study. Cardiogenic ATE was diagnosed based on physical examination and by ultrasonographically-diagnosed left atrial enlargement. Viscoelastic coagulation monitor analysis, CBC, serum biochemistry profile and coagulation profile were performed at admission in cats with ATE. Analysis from healthy control cats was performed using blood collected by direct venipuncture. Our objective was comparison of VCM parameters clot time (CT), clot formation time (CFT), alpha angle (Angle), maximum clot formation (MCF), amplitude at 10 and 20 minutes (A10 and A20, respectively) and clot lysis index at 30 and 45 minutes (LI30 and LI45, respectively) between ATE and control cats.
RESULTS: Cats with ATE had a decreased angle compared to control cats, with a median (range) of 43° (30-48°) compared to 47° (14-59°; P = .01). The parameters A10, A20 and MCF were decreased in ATE cats compared to control cats with a median (range) of 19 units (8-32) compared to 22 units (6-38), 24.5 units (11-40) compared to 29 units (10-47) and 29.5 units (13-44) compared to 33.5 units (14-53), respectively (P = .01, .01 and .01, respectively). The parameters CT, CFT, LI30 and LI45 were similar between groups (P = .22, .09, .62 and .34, respectively).
CONCLUSIONS: Cats with cardiogenic ATE cats have VCM parameters consistent with hypocoagulability compared with healthy cats.

In unfractionated heparin (UFH) monitoring during extracorporeal circulation, the traditional measures of activated clotting time (ACT) or activated partial thromboplastin time (APTT) may diverge, confounding anticoagulant adjustments. We aimed to explore the factors explaining this discrepancy in children and young adults. This retrospective observational study, conducted at an urban regional tertiary hospital, included consecutive pediatric patients who received UFH during extracorporeal circulation (continuous kidney replacement therapy or extracorporeal membrane oxygenation) between April 2017 and March 2021. After patients whose ACT and APTT were not measured simultaneously or who were also taking other anticoagulants were excluded, we analyzed 94 samples from 23 patients. To explain the discrepancy between ACT and APTT, regression equations were created using a generalized linear model (family  =  gamma, link  =  logarithmic) with ACT as the response variable. Other explanatory variables included age, platelet count, and antithrombin. Compared to APTT alone as an explanatory variable, the Akaike information criterion and pseudo-coefficient of determination improved from 855 to 625 and from 0.01 to 0.42, respectively, when these explanatory variables were used. In conclusion, we identified several factors that may explain some of the discrepancy between ACT and APTT in the routinely measured tests. Evaluation of these factors may aid in appropriate adjustments in anticoagulation therapy.

Direct oral anticoagulants (DOACs) exert anticoagulation effect by directly inhibiting Factor Xa (rivaroxaban, apixaban, and edoxaban) or thrombin (dabigatran). Though DOACs are characterized by fixed-dose prescribing and generally do not require routine laboratory drug-level monitoring (DLM), circumstances may arise where the DLM may aid in clinical decision-making, including DOAC dose adjustment, anticoagulant class change, or decisions to withhold or administer reversal agents. We review the current literature that describes high-risk patient groups in which DLM may be beneficial for improved patient anticoagulation management and stewardship. The review also summarizes the limitations of conventional coagulation testing and discuss the emerging utility of quantitative methods for routine and rapid emergent evaluation of DOAC drug levels-in particular, the Anti-Xa activity to detect Factor Xa Inhibitors (rivaroxaban, apixaban, and edoxaban). Both technical and regulatory barriers to widespread DLM implementation are limiting factors to further clinical research that must be overcome, in order to propose universal DOAC DLM strategies and provide clinical-laboratory correlation to formally classify high-risk patient groups.

Thrombin generation (TG) and fibrin clot formation represent the central process of blood coagulation. Up to 95% of thrombin is considered to be generated after the clot is formed. However, this was not investigated in depth. In this study, we conducted a quantitative analysis of the Thrombin at Clot Time (TCT) parameter in 5758 simultaneously recorded TG and clot formation assays using frozen plasma samples from commercial sources under various conditions of activation. These samples were supplemented with clotting factor concentrates, procoagulant lipid vesicles and a fluorogenic substrate and triggered with tissue factor (TF). We found that TCT is often close to a 10% of thrombin peak height (TPH) yet it can be larger or smaller depending on whether the sample has low or high TPH value. In general, the samples with high TPH are associated with elevated TCT. TCT appeared more sensitive to some procoagulant phenotypes than other commonly used parameters such as clotting time, TPH or Thrombin Production Rate (TPR). In a minority of cases, TCT were not predicted from TG parameters. For example, elevated TCT (above 15% of TPH) was associated with either very low or very high TPR values. We conclude that clotting and TG assays may provide complementary information about the plasma sample, and that the TCT parameter may serve as an additional marker for the procoagulant potential in plasma sample.

BACKGROUND: During the coronavirus disease (COVID-19) pandemic, medical resources have often been limited to emergency surgeries. This study aimed to evaluate our experience with delayed surgery for acute type A aortic dissections (ATAADs).
METHODS: A retrospective study was conducted on 33 patients who underwent surgery for ATAADs between January 2020 and December 2021. The patients were divided into two groups: patients treated within 12 h of arrival (E group; N = 21) and those treated > 12 h after arrival (D group; N = 12) with strict antihypertensive therapy until surgery.
RESULTS: The plasma fibrinogen levels on arrival were lower in the D group than in the E group (174.3 ± 109.1 vs 293.4 ± 165.4, p = 0.038). The time to surgery from symptom onset was longer in the D group than in the E group (4 ± 1 h vs. 86 ± 108 h, p < 0.001). There was one case (3%) of mortality and seven cases (21%) of cerebral infarctions in the E group. There was no significant difference in the intraoperative data and quantity of blood transfused between the two groups.
CONCLUSIONS: Thus, delayed surgery for ATAAD with appropriate preoperative management may be an alternative surgical strategy in the COVID-19 era.