A 3-O-sulfated heparan sulfate dodecasaccharide (12-mer) suppresses thromboinflammation and attenuates early organ injury following trauma and hemorrhagic shock.

Introduction: Dysregulated inflammation and coagulation are underlying mechanisms driving organ injury after trauma and hemorrhagic shock. Heparan sulfates, cell surface glycosaminoglycans abundantly expressed on the endothelial surface, regulate a variety of cellular processes. Endothelial heparan sulfate containing a rare 3-O-sulfate modification on a glucosamine residue is anticoagulant and anti-inflammatory through high-affinity antithrombin binding and sequestering of circulating damage-associated molecular pattern molecules. Our goal was to evaluate therapeutic potential of a synthetic 3-O-sulfated heparan sulfate dodecasaccharide (12-mer, or dekaparin) to attenuate thromboinflammation and prevent organ injury. Methods: Male Sprague-Dawley rats were pre-treated subcutaneously with vehicle (saline) or dekaparin (2 mg/kg) and subjected to a trauma/hemorrhagic shock model through laparotomy, gut distention, and fixed-pressure hemorrhage. Vehicle and dekaparin-treated rats were resuscitated with Lactated Ringer's solution (LR) and compared to vehicle-treated fresh-frozen-plasma-(FFP)-resuscitated rats. Serial blood samples were collected at baseline, after induction of shock, and 3 hours after fluid resuscitation to measure hemodynamic and metabolic shock indicators, inflammatory mediators, and thrombin-antithrombin complex formation. Lungs and kidneys were processed for organ injury scoring and immunohistochemical analysis to quantify presence of neutrophils. Results: Induction of trauma and hemorrhagic shock resulted in significant increases in thrombin-antithrombin complex, inflammatory markers, and lung and kidney injury scores. Compared to vehicle, dekaparin treatment did not affect induction, severity, or recovery of shock as indicated by hemodynamics, metabolic indicators of shock (lactate and base excess), or metrics of bleeding, including overall blood loss, resuscitation volume, or hematocrit. While LR-vehicle-resuscitated rodents exhibited increased lung and kidney injury, administration of dekaparin significantly reduced organ injury scores and was similar to organ protection conferred by FFP resuscitation. This was associated with a significant reduction in neutrophil infiltration in lungs and kidneys and reduced lung fibrin deposition among dekaparin-treated rats compared to vehicle. No differences in organ injury, neutrophil infiltrates, or fibrin staining between dekaparin and FFP groups were observed. Finally, dekaparin treatment attenuated induction of thrombin-antithrombin complex and inflammatory mediators in plasma following trauma and hemorrhagic shock. Conclusion: Anti-thromboinflammatory properties of a synthetic 3-O-sulfated heparan sulfate 12-mer, dekaparin, could provide therapeutic benefit for mitigating organ injury following major trauma and hemorrhagic shock.

Influence of TRPM4 rs8104571 genotype on intracranial pressure and outcomes in African Americans with traumatic brain injury.

The TRPM4 gene codes for a membrane ion channel subunit related to inflammation in the central nervous system. Recent investigation has identified an association between TRPM4 single nucleotide polymorphisms (SNPs) rs8104571 and rs150391806 and increased intracranial (ICP) pressure following traumatic brain injury (TBI). We assessed the influence of these genotypes on clinical outcomes and ICP in TBI patients. We included 292 trauma patients with TBI. DNA extraction and real-time PCR were used for TRPM4 rs8104571 and rs150391806 allele discrimination. Five participants were determined to have the rs8104571 homozygous variant genotype, and 20 participants were identified as heterozygotes; 24 of these 25 participants were African American. No participants had rs150391806 variant alleles, preventing further analysis of this SNP. Genotypes containing the rs8104571 variant allele were associated with decreased Glasgow outcome scale-extended (GOSE) score (P = 0.0231), which was also consistent within our African-American subpopulation (P = 0.0324). Regression analysis identified an association between rs8104571 variant homozygotes and mortality within our overall population (P = 0.0230) and among African Americans (P = 0.0244). Participants with rs8104571 variant genotypes exhibited an overall increase in ICP (P = 0.0077), although a greater frequency of ICP measurements > 25 mmHg was observed in wild-type participants (P = < 0.0001). We report an association between the TRPM4 rs8104571 variant allele and poor outcomes following TBI. These findings can potentially be translated into a precision medicine approach for African Americans following TBI utilizing TRPM4-specific pharmaceutical interventions. Validation through larger cohorts is warranted.

Platelet dysfunction persists after trauma despite balanced blood product resuscitation.

BACKGROUND: Platelet activation and aggregation are critical to the initiation of hemostasis after trauma with hemorrhage. Platelet dysfunction is a well-recognized phenomenon contributing to trauma-induced coagulopathy. The goal of this study was to evaluate the timing and severity of platelet dysfunction in massively transfused, traumatically injured patients during the first 72 hours after injury and its association with 30-day survival. METHODS: A retrospective secondary cohort study of platelet count and function was performed using samples from the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Platelet characteristics were measured at 8 timepoints during the first 72 hours of hospitalization and compared between 30-day survivors and nonsurvivors. Platelet counts were assessed via flow cytometry. Platelet function was analyzed with the use of serial thrombelastography and impedance aggregometry with agonists arachidonic acid, adenosine diphosphate, collagen, thrombin receptor activating peptide, and ristocetin. RESULTS: In total, 680 patients were included for analysis. Platelet counts were significantly lower from baseline to 72 hours after hospital admission with further 1.3 to 2-fold reductions noted in nonsurvivors compared to survivor patients. Platelet aggregation via adenosine diphosphate, arachidonic acid, collagen, thrombin receptor activating peptide, and ristocetin was significantly lower in nonsurvivors at all time points. The nadir of platelet aggregation was 2 to 6 hours after admission with significant improvements in viscoelastic maximum clot formation and agonist-induced aggregation by 12 hours without concomitant improvement in platelet count. CONCLUSION: Platelet aggregability recovers 12 hours after injury independent of worsening thrombocytopenia. Failure of platelet function to recover portends a poor prognosis.

Association of Changes in Antithrombin Activity Over Time With Responsiveness to Enoxaparin Prophylaxis and Risk of Trauma-Related Venous Thromboembolism.

Importance: Venous thromboembolism (VTE) affects 2% to 20% of recovering trauma patients, despite aggressive prophylaxis with enoxaparin. Antithrombin is a primary circulating anticoagulant and crucial component of enoxaparin thromboprophylaxis. Approximately 20% of trauma patients present with antithrombin deficiency (antithrombin activity <80%). Objective: To examine time-dependent changes in antithrombin activity, responsiveness to enoxaparin, as measured by anti-factor Xa (anti-FXa) levels, and incidence of VTE after severe trauma and to assess the association of ex vivo antithrombin supplementation with patients' sensitivity to enoxaparin prophylaxis. Design, Setting, and Participants: This single-center, prospective cohort study was performed at a level 1 trauma center between January 7, 2019, and February 28, 2020. Adult trauma patients admitted to the trauma service at high risk for VTE, based on injury pattern and severity, were screened and enrolled. Patients who were older than 70 years, were pregnant, had a known immunologic or coagulation disorder, or were receiving prehospital anticoagulants were excluded. Exposures: Blood samples were collected on emergency department arrival and daily for the first 8 days of hospitalization. Main Outcomes and Measures: Patients' antithrombin activity and anti-FXa levels were measured by a coagulation analyzer, and thrombin generation was measured by calibrated automated thrombography. Responsiveness to enoxaparin was assessed by measuring anti-FXa levels 4 to 6 hours after the first daily enoxaparin dose and compared between patients who developed VTE and who did not. In addition, the associations of ex vivo supplementation of antithrombin with plasma anti-FXa levels were assessed. Results: Among 150 patients enrolled (median [IQR] age, 35 [27-53] years; 37 [24.7%] female and 113 [75.3%] male; 5 [3.3%] Asian, 32 [21.3%] Black, and 113 [75.3%] White; and 51 [34.0%] of Hispanic ethnicity), 28 (18.7%) developed VTE. Patients with VTE had significantly lower antithrombin activity on admission compared with patients without VTE (median [IQR], 91% [79%-104%] vs 100% [88%-112%]; P = .04), as well as lower antithrombin activity on hospital days 5 (median (IQR), 90% [83%-99%] vs 114% [99%-130%]; P = .011), 6 (median [IQR], 97% [81%-109%] vs 123% [104%-134%]; P = .003), 7 (median [IQR], 82% [74%-89%] vs 123% [110%-140%]; P < .001), and 8 (median [IQR], 99% [85%-100%] vs 123% [109%-146%]; P = .011). Anti-FXa levels were significantly lower in patients with VTE vs those without VTE at hospital day 4 (median [IQR], 0.10 [0.05-0.14] IU/mL vs 0.18 [0.13-0.23] IU/mL; P = .006), day 6 (median [IQR], 0.12 [0.08-0.14] IU/mL vs 0.22 [0.13-0.28] IU/mL; P = .02), and day 7 (median [IQR], 0.11 [0.08-0.12] IU/mL vs 0.21 [0.13, 0.28] IU/mL; P = .002). Multivariable analyses found that for every 10% decrease in antithrombin activity during the first 3 days, the risk of VTE increased 1.5-fold. Conclusions and Relevance: The results of this cohort study suggest that after severe trauma, antithrombin deficiency is common and contributes to enoxaparin resistance and VTE. Interventional studies are necessary to determine the efficacy of antithrombin supplementation in the reduction of VTE incidence.

Survival analysis by inflammatory biomarkers in severely injured patients undergoing damage control resuscitation.

BACKGROUND: Although early balanced blood product resuscitation has improved mortality after traumatic injury, many patients still suffer from inflammatory complications. The goal of this study was to identify inflammatory mediators associated with death and multiorgan system failure following severe injury after patients undergo blood product resuscitation. METHODS: A retrospective secondary analysis of inflammatory markers from the Pragmatic Randomized Optimal Platelet and Plasma Ratios study was performed. Twenty-seven serum biomarkers were measured at 8 time points in the first 72 hours of care and were compared between survivors and nonsurvivors. Biomarkers with significant differences were further analyzed by adjudicated cause of 30-day mortality. RESULTS: Biomarkers from 680 patients were analyzed. Seven key inflammatory markers (IL-1ra, IL-6, IL-8, IL-10, eotaxin, IP-10, and MCP-1) were further analyzed. These cytokines were also noted to have the highest hazard ratios of death. Stepwise selection was used for multivariate analysis of survival by time point. MCP-1 at 2 hours, eotaxin and IP-10 at 12 hours, eotaxin at 24 hours, and IP-10 at 72 hours were associated with all-cause mortality. CONCLUSION: Early systemic inflammatory markers are associated with increased risk of mortality after traumatic injury. Future studies should use these biomarkers to prospectively calculate risks of morbidity and causes of mortality for all trauma patients.

Absences of Endothelial Microvesicle Changes in the Presence of the Endotheliopathy of Trauma.

INTRODUCTION: Severe trauma is accompanied by endothelial glycocalyx disruption, which drives coagulopathy, increasing transfusion requirements and death. This syndrome has been termed endotheliopathy of trauma (EOT). Some have suggested EOT results from endothelial cellular damage and apoptosis. Endothelial microvesicles (EMVs) represent cellular damage. We hypothesized that EOT is associated with endothelial damage and apoptosis resulting in an increase in circulating EMVs. METHODS: Prospective, observational study enrolling severely injured patients. Twelve patients with EOT, based on elevated Syndecan-1 levels, were matched with 12 patients with lower levels, based on Injury Severity Score (ISS), abbreviated injury scale profile, and age. Thrombelastography and plasma levels of biomarkers indicative of cellular damage were measured from blood samples collected on admission. EMVs were determined by flow cytometry using varied monoclonal antibodies associated with endothelial cells. Significance was set at P < 0.05. RESULTS: Admission physiology and ISS (29 vs. 28) were similar between groups. Patients with EOT had higher Syndecan-1, 230 (158, 293) vs. 19 (14, 25) ng/mL, epinephrine, and soluble thrombomodulin levels. Based on thrombelastography, EOT had reductions in clot initiation, amplification, propagation and strength, and a greater frequency of transfusion, 92% vs. 33%. There were no differences in EMVs irrespective of the antibody used. Plasma norepinephrine, sE-selectin, sVE-cadherin, and histone-complexed DNA fragments levels were similar. CONCLUSION: In trauma patients presenting with EOT, endothelial cellular damage or apoptosis does not seem to occur based on the absence of an increase in EMVs and other biomarkers. Thus, this suggests endothelial glycocalyx disruption is the underlying primary cause of EOT.

Microvesicle phenotypes are associated with transfusion requirements and mortality in subjects with severe injuries.

BACKGROUND: Severe injury often results in substantial bleeding and mortality. Injury provokes cellular activation and release of extracellular vesicles. Circulating microvesicles (MVs) are predominantly platelet-derived and highly procoagulant. They support hemostasis and vascular function. The roles of MVs in survival after severe injury are largely unknown. We hypothesized that altered MV phenotypes would be associated with transfusion requirements and poor outcomes. METHODS: This single-centre study was approved by the Institutional Review Board. The study cohort consisted of patients with major trauma requiring blood product transfusion and 26 healthy controls. Plasma samples for MVs were collected upon admission to the emergency department (n=169) and post-resuscitation (n=42), and analysed by flow cytometry for MV counts and cellular origin: platelet (PMV), erythrocyte (RMV), leukocyte (LMV), endothelial (EMV), tissue factor (TFMV), and annexin V (AVMV). Twenty-four hour mortality is the outcome measurement used to classify survivors versus non-survivors. Data were compared over time and analysed with demographic and clinical data. RESULTS: The median age was 34 (IQR 23, 51), 72% were male, Injury Severity Score was 29 (IQR 19, 36), and 24 h mortality was 13%. MV levels and phenotypes differed between patients and controls. Elevated admission EMVs were found both in survivors (409/µL) and non-survivors (393/µL) compared to controls (23/µL, p<0.001) and persisted over time. Admission levels of PMV, AVMV, RMV, and TFMV were significantly lower in patients who died compared to survivors, but were not independently associated with the 24 h mortality rate. Patients with low MV levels at admission received the most blood products within the first 24 h. AVMV and PMV levels either increased over time or stabilized in survivors but decreased in non-survivors, resulting in significantly lower levels at intensive care unit admission in non-survivors (1,048 vs. 1,880 AVMV/µL, p<0.00004 and 1,245 PMP/µL vs. 1,866 PMP/µL, p=0.003). CONCLUSION: Severe injury results in endothelial activation and altered MV phenotypes. Significant differences in specific MV phenotypes or changes over time were associated with blood product requirements and the 24 h mortality rate.

Cellular microparticle and thrombogram phenotypes in the Prospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study: correlation with coagulopathy.

BACKGROUND: Trauma-induced coagulopathy following severe injury is associated with increased bleeding and mortality. Injury may result in alteration of cellular phenotypes and release of cell-derived microparticles (MP). Circulating MPs are procoagulant and support thrombin generation (TG) and clotting. We evaluated MP and TG phenotypes in severely injured patients at admission, in relation to coagulopathy and bleeding. METHODS: As part of the Prospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study, research blood samples were obtained from 180 trauma patients requiring transfusions at 5 participating centers. Twenty five healthy controls and 40 minimally injured patients were analyzed for comparisons. Laboratory criteria for coagulopathy was activated partial thromboplastin time (APTT) ≥ 35 sec. Samples were analyzed by Calibrated Automated Thrombogram to assess TG, and by flow cytometry for MP phenotypes [platelet (PMP), erythrocyte (RMP), leukocyte (LMP), endothelial (EMP), tissue factor (TFMP), and Annexin V positive (AVMP)]. RESULTS: 21.7% of patients were coagulopathic with the median (IQR) APTT of 44 sec (37, 53), and an Injury Severity Score of 26 (17, 35). Compared to controls, patients had elevated EMP, RMP, LMP, and TFMP (all p<0.001), and enhanced TG (p<0.0001). However, coagulopathic PROMMTT patients had significantly lower PMP, TFMP, and TG, higher substantial bleeding, and higher mortality compared to non-coagulopathic patients (all p<0.001). CONCLUSIONS: Cellular activation and enhanced TG are predominant after trauma and independent of injury severity. Coagulopathy was associated with lower thrombin peak and rate compared to non-coagulopathic patients, while lower levels of TF-bearing PMPs were associated with substantial bleeding.

Establishment of methods for performing thrombelastography and calibrated automated thrombography in rats.

Rodent models of hemorrhagic shock are paramount to our understanding of the pathophysiology of this disease, the effects on coagulation and in exploring the utility of resuscitative methods for managing patients in shock. These models usually require serial blood sampling during experimentation. The lack of standardized practices for these experimental models has resulted in technical variability, discordance in the literature, and incomparable results on blood coagulation analysis between researchers, hindering substantial progress in the field of hemorrhagic shock. The aim of this study was to define the effects of cardiac puncture versus arterial catheterization on coagulation in a rat model to provide data supporting standardization of one practice over another. Blood was collected from anesthetized rats via cardiac puncture or femoral artery catheterization and hemostatic potential analyzed by thrombelastography and calibrated automated thrombography. Our data show that blood collected via cardiac puncture demonstrated hypercoagulability as indicated by faster rates of clot formation and thrombin generation, increased overall clot strength, and a greater thrombin-generating capacity when compared with blood collected via femoral artery catheter. We conclude that blood collection methods have a profound effect on hemostatic potential, and standardization of these practices is necessary to define the effects of shock on coagulation in rodents.

Association of hemodilution and blood pressure in uncontrolled bleeding.

BACKGROUND: Hemodynamic status and coagulation capacity affect blood loss after injury. The most advantageous fluid and blood pressure to optimize resuscitation and minimize perturbation of coagulation are unclear. We investigated interactions of isovolumic hemodilution on hemodynamics, coagulation, and blood loss after injury. METHODS: Twenty-five male rats were randomized into three groups (Whole Blood Uncontrolled Blood Pressure [WBU], n = 7; Lactated Ringers Uncontrolled Blood Pressure [LRU], n = 10; Whole Blood Controlled Blood Pressure [WBC], n = 8) with isovolumic hemodilution of 50% blood volume, with and without control of pre-injury blood pressure. All rats underwent uniform grade IV liver injury 30 min after serial exchanges. Post-injury blood loss and coagulation function were measured. RESULTS: Dilution occurred, determined by hematocrit, with LRU having a greater reduction. Pre-injury mean arterial pressure (MAP) decreased compared with baseline (98 ± 7 mmHg) with LRU (62 ± 14 mmHg) and WBC (61 ± 10 mmHg), resulting in WBU (101 ± 13 mmHg) being significantly higher and not changed from baseline. Post-injury, MAP decreased from pre-injury, with LRU significantly lower than the other two groups. No differences were observed in prothrombin time/international normalized ratio or thromboelastography. Bleed volume was significantly different between groups: WBU < WBC < LRU and associated with the pre-injury MAP. Controlling baseline MAP, dilution with Lactated Ringers (LR) resulted in greater blood loss than whole blood (3.0 ± 0.4 versus 1.9 ± 0.3 mL). CONCLUSIONS: In this rat model of liver injury, blood loss was associated with baseline MAP and type of fluid used for dilution. Hemodilution with LR did not produce coagulopathy based on laboratory values. When controlling baseline MAP, dilution with LR increased bleeding, confirming a functional coagulopathic state.

Influence of resuscitation fluids, fresh frozen plasma and antifibrinolytics on fibrinolysis in a thrombelastography-based, in-vitro, whole-blood model.

Hyperfibrinolysis has been identified as a mechanism of trauma coagulopathy associated with poor outcome. The aim of the study was to create a trauma coagulopathy model (TCM) with a hyperfibrinolysis thrombelastography (TEG) pattern similar to injured patients and test the effects of different resuscitation fluids and antifibrinolytics on fibrinolysis. TCM was established from whole blood by either 15% dilution with isotonic saline, lactated Ringer's, Plasma-Lyte, 5% albumin, Voluven, Hextend, 6% dextran in isotonic saline or 30% dilution with lactated Ringer's plus Voluven and supplementation with tissue factor and tissue plasminogen activator (tPA). These combinations resulted in a TCM that could then be 'treated' with tranexamic acid (TXA) or 6-aminocaproic acid (ACA). Clot formation was evaluated by TEG. Whole-blood dilution by 15% with crystalloids and albumin in the presence of tissue factor plus tPA resulted in an abnormal TEG pattern and increased fibrinolysis, as did dilution with synthetic colloids. TXA 1 µg/ml or ACA 10 µg/ml were sufficient to suppress fibrinolysis when TCM was diluted 15% with lactated Ringer's, but 3 µg/ml of TXA or 30 µg/ml of ACA were needed for fibrinolysis inhibition induced by simultaneous euvolemic dilution with lactated Ringer's plus Voluven by 30%. A total of 15% dilution of whole blood in the presence of tissue factor plus tPA results in a hyperfibrinolysis TEG pattern similar to that observed in severely injured patients. Synthetic colloids worsen TEG variables with a further increase of fibrinolysis. Low concentrations of TXA or ACA reversed hyperfibrinolysis, but the efficient concentrations were dependent on the degree of fibrinolysis and whole-blood dilution.

Hemostatically distinct FFPs equally improve abnormal TEG variables in an in vitro dilutional coagulopathy model.

INTRODUCTION: To improve fresh frozen plasma (FFP) availability, thawed plasma is stored at 4°C for up to 5 days and considered equivalent to freshly thawed FFP. However, we have shown that hemostatic potential of thawed plasma is highly variable between donors and significantly diminished during storage. We hypothesized that smaller volumes of plasma with higher hemostatic potential (FFP-H) would be needed to restore normal thrombelastogram (TEG) values compared to plasma with lower hemostatic potential (FFP-L). MATERIALS AND METHODS: A dilutional coagulopathy model was established from whole blood by diluting plasma with saline to 23%, while cellular components were kept unchanged. Saline was gradually replaced with equal volumes of FFPs with distinctive hemostatic potentials, which was evaluated by the calibrated automated thrombogram. Clot formation in the presence of tissue factor was evaluated by TEG at baseline and after addition of increasing concentrations of FFP-H and FFP-L. RESULTS: Blood dilution with saline in the presence of tissue factor resulted in abnormal TEGs that resemble a pattern observed in severely bleeding trauma patients. All FFPs produced similar improvements in TEG variables despite different hemostatic potentials. TEG changes were solely dependent on FFP volume and reached the normal reference range when plasma concentration increased to 40%. CONCLUSION: Plasma dilution and tissue factor in whole blood results in an abnormal TEG with a hyperfibrinolytic pattern. A plasma concentration of at least 40% was necessary for TEG normalization after dilution with saline. An effect of FFPs' hemostatic potential on clot formation could not be detected by TEG in this in vitro model.

Decline in platelet microparticles contributes to reduced hemostatic potential of stored plasma.

INTRODUCTION: In an effort to administer life-saving transfusions quickly, some trauma centers maintain thawed plasma (TP). According to AABB, TP is approved for transfusion for up to five days when stored at 1-6° C. However, the alterations in microparticles (MP) contained in the plasma, which are an integral component of plasma's hemostatic capacity, are not well characterized. We report on MP changes in TP between its initial thaw (FFP-0) and five days (FFP-5) of storage. MATERIALS AND METHODS: FFP units (n=30) were thawed at 37° C and kept refrigerated for five days. Phenotypes of residual cells, which include platelets, erythrocytes, leukocytes, monocytes, endothelial cells, and MP counterparts of each cell type, were analyzed by flow cytometry. Functional assays were used for MP procoagulant activity, plasma thrombin generation, and clotting properties (thromboelastography). RESULTS: In FFP-0 the majority (94%) of residual cells were platelets, along with significant levels of platelet MPs (4408 × 10(3)/L). FFP-5 showed a decline in MP count by 50% (p<0.0001), and procoagulant activity by 29% (p<0.0001). FFP-5 exhibited only 54% (p<0.0001) of the potential for thrombin generation as FFP-0, while thromboelastography indicated a slower clotting response (p<0.0001) and a longer delay in reaching maximum clot (p<0.01). Removal of MP by filtration resulted in reduced thrombin generation, while the MP replacement restored it. CONCLUSIONS: Decline in MP with storage contributes to FFP-5's reduced ability to provide the hemostatic potential exhibited by FFP-0, suggesting the presence of platelet MPs in freshly TP may be beneficial and protective in the initial treatment of hemorrhage.

Multiple levels of degradation diminish hemostatic potential of thawed plasma.

BACKGROUND: Severe bleeding after injury requires transfusion of blood products, including fresh frozen plasma (FFP). Many centers are keeping thawed plasma (TP) ready for massively transfused patients. According to the American Association of Blood Banks Standards, TP is approved for transfusion up to 5 days after thawing, when stored at 1°C to 6°C. However, there are no clinical data analyzing the effects of the approved 5-day storage on plasma. We hypothesize that the hemostatic potential (HP) of freshly thawed (FFP-0) was superior to plasma stored for 5 days (FFP-5). METHODS: FFP from 30 single donors were thawed at 37°C and kept at 1°C to 6°C for 5 days. HP was evaluated at day 0 and 5 by measuring kinetics of thrombin generation (TG), kinetics of clot formation by thromboelastography, clotting factors and inhibitors, and cell-derived microparticles (MPs) by flow cytometry. RESULTS: When comparing FFP-5 to FFP-0, FFP-5 exhibited only 40% of the potential of FFP-0 for TG (6.2 nM/min vs. 14.3 nM/min, p<0.0001), a slower clotting response via thromboelastography (reaction time: 4.3 minutes vs. 3.2 minutes, p<0.0001) and a longer delay in reaching maximum thrombus generation (5.7 minutes vs. 4.6 minutes, p<0.01). Diminished HP was accompanied by a significant decline in multiple coagulation proteins, including FV, VII, VIII, von Willebrand factor, and free Protein S, by up to 30%, and a decrease of 50% in MP counts. CONCLUSION: The HP and clot forming ability of TP significantly declined with storage. Hence, freshly TP may have a greater ability to restore hemostasis and correct coagulopathy compared with FFP-5. The clinical consequences for transfused patients deserve further exploration.

Assessment of coronary heart disease risk by combined analysis of coagulation factors.

OBJECTIVE: Prospective studies have reported a positive association of coagulation factors with risk of coronary heart disease (CHD). It is unclear whether these coagulation factors interact. METHODS AND RESULTS: Using a prospective case-cohort design, we analyzed by Cox proportional hazard regression interactions between soluble thrombomodulin (sTM) and fibrinogen, factor VIII (FVIII), FVII, or plasminogen activator inhibitor-1 (PAI-1) in 410 CHD cases and 721 non-cases from the Atherosclerosis Risk in Communities (ARIC). There was a significant interaction between sTM and fibrinogen (p=0.027). We next assessed risk ratios (RR) by combined tertile analysis. Combined analysis revealed that being in the upper sTM tertile counteracted the CHD risk imposed by higher fibrinogen whereas being in the lower sTM tertile amplified the CHD risk of higher fibrinogen. sTM and fibrinogen mutually influenced CHD incidence in a concentration-dependent manner. When analyzed as single factors by tertiles, FVIII, FVII and PAI-1 were not associated with CHD. However, when analyzed together with sTM, FVIII and PAI-1 were both positively associated with CHD for those in the lower sTM tertile. CONCLUSION: There is a complex interaction between sTM and prothrombotic coagulation factors. Combined analysis improves CHD risk assessment.