Browsing by Subject "Blood Coagulation"

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Open Access
Andexanet alfa for the reversal of Factor Xa inhibitor related anticoagulation
(Expert review of hematology, 2016-01) Ghadimi, K; Welsby, IJ; Levy, JH; Dombrowski, KE
Andexanet alfa is a specific reversal agent for Factor Xa inhibitors. The molecule is a recombinant protein analog of factor Xa that binds to Factor Xa inhibitors and antithrombin:LMWH complex but does not trigger prothrombotic activity. In ex vivo, animal, and volunteer human studies, andexanet alfa (AnXa) was able to dose-dependently reverse Factor Xa inhibition and restore thrombin generation for the duration of drug administration. Further trials are underway to examine its safety and efficacy in the population of patients experiencing FXa inhibitor-related bleeding.
Open Access
Aprotinin improves functional outcome but not cerebral infarct size in an experimental model of stroke during cardiopulmonary bypass.
(Anesthesia and analgesia, 2010-07) Homi, H Mayumi; Sheng, Huaxin; Arepally, Gowthami M; Mackensen, G Burkhard; Grocott, Hilary P
Background
Aprotinin, a nonspecific serine protease inhibitor, has been used to decrease bleeding and reduce the systemic inflammatory response after cardiopulmonary bypass (CPB). Studies have variably linked aprotinin administration with both improved as well as adverse cerebral consequences after cardiac surgery. We designed this study to determine whether an antiinflammatory dose of aprotinin could improve the histologic and functional neurologic outcome in a rat model of focal cerebral ischemia during CPB.
Methods
After surgical preparation, the animals were randomized into 2 groups: an aprotinin group (60,000 kIU/kg IV) and a control group (0.9% NaCl IV). Normothermic CPB was performed for 60 minutes during which time a partial overlapping 60 minutes of right middle cerebral artery occlusion was induced. Cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-6, and IL-10) were measured at baseline, the end of CPB, then 2 and 24 hours after CPB. On postoperative day 3, the animals underwent functional neurologic testing and histologic assessment of cerebral infarct volume.
Results
There was a reduction in systemic inflammation in the aprotinin group compared with the control group, demonstrated by lower levels of IL-1beta (P = 0.035) and IL-6 (P = 0.047). The aprotinin group also had a better functional neurologic performance (median [interquartile range]: aprotinin 27 [8] vs control 32 [6]; P = 0.042). However, there was no difference in cerebral infarct volume (aprotinin 306 [27] mm(3) vs control 297 [52] mm(3); P = 0.599).
Conclusions
In this experimental model of stroke occurring during CPB, aprotinin decreased the systemic inflammatory response to CPB. Although there was no difference in the cerebral infarct volume, there was a small improvement in the short-term functional neurologic outcome in the aprotinin group.
Open Access
Coagulation Conundrum: an Exercise in Clinical Reasoning.
(Journal of general internal medicine, 2023-02) Pohlman, F Will; Minter, Daniel J; Cunningham, Hayley E; DiNardo, Katherine; Onwuemene, Oluwatoyosi A
Open Access
Effect of apixaban compared with warfarin on coagulation markers in atrial fibrillation.
(Heart (British Cardiac Society), 2019-02) Christersson, Christina; Wallentin, Lars; Andersson, Ulrika; Alexander, John H; Alings, Marco; De Caterina, Raffaele; Gersh, Bernard J; Granger, Christopher B; Halvorsen, Sigrun; Hanna, Michael; Huber, Kurt; Hylek, Elaine M; Lopes, Renato D; Oh, Byung-Hee; Siegbahn, Agneta
Objectives
Compare the effect of apixaban and warfarin on coagulation and primary haemostasis biomarkers in atrial fibrillation (AF).
Methods
The biomarker substudy from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial included 4850 patients with AF randomised to treatment with apixaban or warfarin. Sixty per cent of patients used vitamin K antagonist (VKA) within 7 days before randomisation. Prothrombin fragment 1+2 (F1+2), D-dimer, soluble CD40 ligand (sCD40L) and von Willebrand factor (vWF) antigen were analysed at randomisation and after 2 months of study treatment.
Results
In patients not on VKA treatment at randomisation, F1+2 and D-dimer levels were decreased by 25% and 23%, respectively, with apixaban, and by 59% and 38%, respectively, with warfarin (p<0.0001 for treatment differences for both). In patients on VKA at randomisation, F1+2 and D-dimer levels increased by 41% and 10%, respectively, with apixaban and decreased by 37% and 11%, respectively, with warfarin (p<0.0001 for treatment differences for both). sCD40L levels were slightly increased at 2 months, regardless of VKA or randomised treatment. Apixaban and warfarin also both reduced vWF antigen regardless of VKA treatment. The efficacy (stroke) and safety (bleeding) of apixaban compared with warfarin was similar irrespectively of biomarker levels at 2 months.
Conclusions
Treatment with apixaban compared with warfarin for stroke prevention in patients with AF was associated with less reduction in thrombin generation and fibrin turnover. This effect of apixaban could contribute to the clinical results where apixaban was superior to warfarin both in stroke prevention and in reducing bleeding risk.
Trial registration number
NCT00412984.
Open Access
Effects of therapeutic plasma exchange on anticoagulants in patients receiving therapeutic anticoagulation: a systematic review.
(Transfusion, 2019-05) Hodulik, Kimberly L; Root, Adam G; Ledbetter, Leila S; Onwuemene, Oluwatoyosi A
Therapeutic plasma exchange (TPE) removes coagulation proteins, but its impact on therapeutic anticoagulation is unknown. We performed a systematic review of the literature to determine the coagulation effects of TPE in patients receiving systemic anticoagulation. We searched MEDLINE, CINAHL, EMBASE, and Web of Science until June 2018 for studies combining controlled vocabulary and keywords related to therapeutic plasma exchange, plasmapheresis, anticoagulants, and therapy. The primary outcome was the effect of TPE on anti-Xa activity, activated partial thromboplastin time (aPTT), or international normalized ratio (INR). The secondary outcome was reports of post-TPE bleeding or thrombosis. A total of 1830 references were screened and eight studies identified. Our selected studies (five case reports and three case series) involved 23 patients and evaluated the effects of seven anticoagulants. Six studies of unfractionated heparin, low-molecular-weight heparins, and direct oral anticoagulants demonstrated an anti-Xa level decline. Two studies of unfractionated heparin and low-molecular-weight heparins showed an aPTT increase. One study of warfarin showed a post-TPE INR increase. Reports of post-TPE bleeding occurred in two patients and thrombosis in one. In patients receiving therapeutic anticoagulation, TPE is associated with anti-Xa activity decline and aPTT and INR increase. These coagulation changes do not appear to significantly increase bleeding or thrombotic risk. Our data suggest the need for prospective studies to investigate the true clinical impact of TPE on therapeutic anticoagulation.
Open Access
Exposure to concentrated coarse air pollution particles causes mild cardiopulmonary effects in healthy young adults.
(Environmental health perspectives, 2009-07) Graff, Donald W; Cascio, Wayne E; Rappold, Ana; Zhou, Haibo; Huang, Yuh-Chin T; Devlin, Robert B
BACKGROUND: There is ample epidemiologic and toxicologic evidence that exposure to fine particulate matter (PM) air pollution [aerodynamic diameter < or = 2.5 microm (PM(2.5))], which derives primarily from combustion processes, can result in increased mortality and morbidity. There is less certainty as to the contribution of coarse PM (PM(2.5-10)), which derives from crustal materials and from mechanical processes, to mortality and morbidity. OBJECTIVE: To determine whether coarse PM causes cardiopulmonary effects, we exposed 14 healthy young volunteers to coarse concentrated ambient particles (CAPs) and filtered air. Coarse PM concentration averaged 89.0 microg/m(3) (range, 23.7-159.6 microg/m(3)). Volunteers were exposed to coarse CAPs and filtered air for 2 hr while they underwent intermittent exercise in a single-blind, crossover study. We measured pulmonary, cardiac, and hematologic end points before exposure, immediately after exposure, and again 20 hr after exposure. RESULTS: Compared with filtered air exposure, coarse CAP exposure produced a small increase in polymorphonuclear neutrophils in the bronchoalveolar lavage fluid 20 hr postexposure, indicating mild pulmonary inflammation. We observed no changes in pulmonary function. Blood tissue plasminogen activator, which is involved in fibrinolysis, was decreased 20 hr after exposure. The standard deviation of normal-to-normal intervals (SDNN), a measure of overall heart rate variability, also decreased 20 hr after exposure to CAPs. CONCLUSIONS: Coarse CAP exposure produces a mild physiologic response in healthy young volunteers approximately 20 hr postexposure. These changes are similar in scope and magnitude to changes we and others have previously reported for volunteers exposed to fine CAPs, suggesting that both size fractions are comparable at inducing cardiopulmonary changes in acute exposure settings.
Open Access
Hemostatic effects of therapeutic plasma exchange: A concise review.
(Journal of clinical apheresis, 2022-06) Soares Ferreira Júnior, Alexandre; Hodulik, Kimberly; Barton, Karen D; Onwuemene, Oluwatoyosi A
Therapeutic plasma exchange (TPE) alters the hemostatic balance. Contributing to TPE's hemostatic effects is the mechanical processing of blood in the extracorporeal circuit, circuit anticoagulant, type of replacement fluid, TPE schedule and number of procedures, TPE timing relative to invasive procedures, and removal of nontargeted components such as platelets, coagulation proteins, and cytokines. Although TPE's hemostatic effects are well established, how it impacts the bleeding risk is not clearly understood. In this concise review, we describe the effects of the above TPE-related factors on hemostatic balance, present data on the effects of TPE on blood hemostasis, including its effects on platelet counts and clotting assays, and review the literature on the impact of TPE-induced hemostatic changes on TPE-associated bleeding events. Finally, we discuss risk factors associated with bleeding during TPE and review the literature on TPE-associated hemostatic effects in the pediatric population.
Open Access
Modelling the linkage between influenza infection and cardiovascular events via thrombosis.
(Scientific reports, 2020-08-31) McCarthy, Zachary; Xu, Shixin; Rahman, Ashrafur; Bragazzi, Nicola Luigi; Corrales-Medina, Vicente F; Lee, Jason; Seet, Bruce T; Neame, Dion; Thommes, Edward; Heffernan, Jane; Chit, Ayman; Wu, Jianhong
There is a heavy burden associated with influenza including all-cause hospitalization as well as severe cardiovascular and cardiorespiratory events. Influenza associated cardiac events have been linked to multiple biological pathways in a human host. To study the contribution of influenza virus infection to cardiovascular thrombotic events, we develop a dynamic model which incorporates some key elements of the host immune response, inflammatory response, and blood coagulation. We formulate these biological systems and integrate them into a cohesive modelling framework to show how blood clotting may be connected to influenza virus infection. With blood clot formation inside an artery resulting from influenza virus infection as the primary outcome of this integrated model, we demonstrate how blood clot severity may depend on circulating prothrombin levels. We also utilize our model to leverage clinical data to inform the threshold level of the inflammatory cytokine TNFα which initiates tissue factor induction and subsequent blood clotting. Our model provides a tool to explore how individual biological components contribute to blood clotting events in the presence of influenza infection, to identify individuals at risk of clotting based on their circulating prothrombin levels, and to guide the development of future vaccines to optimally interact with the immune system.
Open Access
Prothrombin Complex Concentrates for Bleeding in the Perioperative Setting.
(Anesth Analg, 2016-05) Ghadimi, Kamrouz; Levy, Jerrold H; Welsby, Ian J
Prothrombin complex concentrates (PCCs) contain vitamin K-dependent clotting factors (II, VII, IX, and X) and are marketed as 3 or 4 factor-PCC formulations depending on the concentrations of factor VII. PCCs rapidly restore deficient coagulation factor concentrations to achieve hemostasis, but like with all procoagulants, the effect is balanced against thromboembolic risk. The latter is dependent on both the dose of PCCs and the individual patient prothrombotic predisposition. PCCs are approved by the US Food and Drug Administration for the reversal of vitamin K antagonists in the setting of coagulopathy or bleeding and, therefore, can be administered when urgent surgery is required in patients taking warfarin. However, there is growing experience with the off-label use of PCCs to treat patients with surgical coagulopathic bleeding. Despite their increasing use, there are limited prospective data related to the safety, efficacy, and dosing of PCCs for this indication. PCC administration in the perioperative setting may be tailored to the individual patient based on the laboratory and clinical variables, including point-of-care coagulation testing, to balance hemostatic benefits while minimizing the prothrombotic risk. Importantly, in patients with perioperative bleeding, other considerations should include treating additional sources of coagulopathy such as hypofibrinogenemia, thrombocytopenia, and platelet disorders or surgical sources of bleeding. Thromboembolic risk from excessive PCC dosing may be present well into the postoperative period after hemostasis is achieved owing to the relatively long half-life of prothrombin (factor II, 60-72 hours). The integration of PCCs into comprehensive perioperative coagulation treatment algorithms for refractory bleeding is increasingly reported, but further studies are needed to better evaluate the safe and effective administration of these factor concentrates.
Open Access
Strong Binding of Platelet Integrin αIIbβ3 to Fibrin Clots: Potential Target to Destabilize Thrombi.
(Scientific reports, 2017-10-11) Höök, Peter; Litvinov, Rustem I; Kim, Oleg V; Xu, Shixin; Xu, Zhiliang; Bennett, Joel S; Alber, Mark S; Weisel, John W
The formation of platelet thrombi is determined by the integrin αIIbβ3-mediated interactions of platelets with fibrinogen and fibrin. Blood clotting in vivo is catalyzed by thrombin, which simultaneously induces fibrinogen binding to αIIbβ3 and converts fibrinogen to fibrin. Thus, after a short time, thrombus formation is governed by αIIbβ3 binding to fibrin fibers. Surprisingly, there is little understanding of αIIbβ3 interaction with fibrin polymers. Here we used an optical trap-based system to measure the binding of single αIIbβ3 molecules to polymeric fibrin and compare it to αIIbβ3 binding to monomeric fibrin and fibrinogen. Like αIIbβ3 binding to fibrinogen and monomeric fibrin, we found that αIIbβ3 binding to polymeric fibrin can be segregated into two binding regimes, one with weaker rupture forces of 30-60 pN and a second with stronger rupture forces >60 pN that peaked at 70-80 pN. However, we found that the mechanical stability of the bimolecular αIIbβ3-ligand complexes had the following order: fibrin polymer > fibrin monomer > fibrinogen. These quantitative differences reflect the distinct specificity and underlying molecular mechanisms of αIIbβ3-mediated reactions, implying that targeting platelet interactions with fibrin could increase the therapeutic indices of antithrombotic agents by focusing on the destabilization of thrombi rather than the prevention of platelet aggregation.
Open Access
Three-factor prothrombin complex concentrates for refractory bleeding after cardiovascular surgery within an algorithmic approach to haemostasis.
(Vox sanguinis, 2019-05) Hashmi, Nazish K; Ghadimi, Kamrouz; Srinivasan, Amudan J; Li, Yi-Ju; Raiff, Robert D; Gaca, Jeffrey G; Root, Adam G; Barac, Yaron D; Ortel, Thomas L; Levy, Jerrold H; Welsby, Ian J
BACKGROUND/OBJECTIVES:Prothrombin complex concentrates (PCC) are increasingly administered off-label in the United States to treat bleeding in cardiovascular surgical patients and carry the potential risk for acquired thromboembolic side-effects after surgery. Therefore, we hypothesized that the use of low-dose 3-factor (3F) PCC (20-30 IU/kg), as part of a transfusion algorithm, reduces bleeding without increasing postoperative thrombotic/thromboembolic complications. MATERIALS/METHODS:After IRB approval, we retrospectively analysed 114 consecutive, complex cardiovascular surgical patients (age > 18 years), between February 2014 and June 2015, that received low-dose 3F-PCC (Profilnine® ), of which seven patients met established exclusion criteria. PCC was dosed according to an institutional perioperative algorithm. Allogeneic transfusions were recorded before and after PCC administration (n = 107). The incidence of postoperative thromboembolic events was determined within 30 days of surgery, and Factor II levels were measured in a subset of patients (n = 20) as a quality control measure to avoid excessive PCC dosing. RESULTS:Total allogeneic blood product transfusion reached a mean of 12·4 ± 9·9 units before PCC and 5·0 ± 6·3 units after PCC administration (P < 0·001). The mean PCC dose was 15·8 ± 7·1 IU/kg. Four patients (3·8%) each experienced an ischaemic stroke on postoperative day 1, 2, 4 and 27. Seven patients (6·5%) had acquired venous thromboembolic disease within 10 days of surgery. Median factor II level after transfusion algorithm adherence and PCC administration was 87%. CONCLUSIONS:3F-PCC use for refractory bleeding after cardiovascular surgery resulted in reduced transfusion of allogeneic blood and blood products. Adherence to this algorithmic approach was associated with an acceptable incidence of postoperative thrombotic/thromboembolic complications.
Open Access
Up-regulation of tissue factor in human pulmonary artery endothelial cells after ultrafine particle exposure.
(Environmental health perspectives, 2007-04) Karoly, ED; Li, Z; Dailey, LA; Hyseni, X; Huang, YC
BACKGROUND: Epidemiology studies have linked exposure to pollutant particles to increased cardiovascular mortality and morbidity, but the mechanisms remain unknown. OBJECTIVES: We tested the hypothesis that the ultrafine fraction of ambient pollutant particles would cause endothelial cell dysfunction. METHODS: We profiled gene expression of human pulmonary artery endothelial cells (HPAEC) exposed to ultrafine particles (UFPs; 100 microg/mL) from Chapel Hill, North Carolina, or vehicle for 4 hr with Affymetrix HG U133 Plus 2.0 chips (n = 4 each). RESULTS: We found 320 up-regulated genes and 106 down-regulated genes (p < 0.01, 5% false discovery rate). We noted up-regulation of genes related to coagulation [tissue factor (F3) and coagulation factor II receptor-like 2 (F2RL2)] and differential regulation of genes related to F3 signaling (FOS, JUN, and NFKBIA). Results of quantitative polymerase chain reaction show a significant up-regulation of F3 after 10 and 100 microg/mLUFP exposures. Additionally, the water-soluble fractions of UFPs were sufficient to induce the expression of F3, F2RL2, and heme oxygenase 1 (HMOX1). Treatment of HPAEC with UFPs for 16 hr increased the release of interleukin (IL)-6 and IL-8. Pretreatment of HPAEC with a blocking antibody against F3 attenuated IL-6 and IL-8 release by 30 and 70%, respectively. CONCLUSIONS: Using gene profiling, we discovered that UFPs may induce vascular endothelial cells to express genes related to clotting. These results indicate that PM may cause adverse cardiovascular health effects by activating coagulation-inflammation circuitry.
Open Access
Use of PER977 to reverse the anticoagulant effect of edoxaban.
(N Engl J Med, 2014-11-27) Ansell, Jack E; Bakhru, Sasha H; Laulicht, Bryan E; Steiner, Solomon S; Grosso, Michael; Brown, Karen; Dishy, Victor; Noveck, Robert J; Costin, James C

Browsing by Subject "Blood Coagulation"

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