The effect of fresh frozen plasma in critically ill patients

Increased In Vivo Thrombin Generation in Patients with Localized Non-Small Cell Lung Cancer Unfit for Surgery

Patients with lung cancer face a substantially increased risk of thromboembolic disease. Patients with localized non-small cell lung cancer (NSCLC) who are unfit for surgery due to age or comorbidity have additional thrombotic risk factors. Thus, we aimed to investigate markers of primary and secondary hemostasis, since this could assist in treatment decisions. We included 105 patients with localized NSCLC. Ex vivo thrombin generation was determined by calibrated automated thrombogram and in vivo thrombin generation was determined by measurement of thrombin-antithrombin complex (TAT) levels and prothrombin fragment F1 + 2 concentrations (F1 + 2). Platelet aggregation was investigated by impedance aggregometry. Healthy controls were used for comparison. TAT and F1 + 2 concentrations were significantly higher in NSCLC patients than in healthy controls (P < .001). The levels of ex vivo thrombin generation and platelet aggregation were not increased in the NSCLC patients. Patients with localized NSCLC considered unfit for surgery had significantly increased in vivo thrombin generation. This finding should be further investigated as it could be relevant for the choice of thromboprophylaxis in these patients.

Age-dependent thrombin generation predicts 30-day mortality and symptomatic thromboembolism after multiple trauma

Trauma-induced coagulopathy (TIC) is a risk factor for death and is associated with deviations in thrombin generation. TIC prevalence and thrombin levels increase with age. We assayed in vivo and ex vivo thrombin generation in injured patients (n = 418) to specifically investigate how age impacts thrombin generation in trauma and to address the prognostic ability of thrombin generation. Biomarkers of thrombin generation were elevated in young (< 40 years) and older (≥ 40 years) trauma patients. In vivo thrombin generation was associated with Injury Severity Score (ISS) and this association was stronger in young than older patients. In vivo thrombin generation decreased faster after trauma in the young than the older patients. Across age groups, in vivo thrombin generation separated patients dying/surviving within 30 days at a level comparable to the ISS score (AUC 0.80 vs. 0.82, p > 0.76). In vivo and ex vivo thrombin generation also predicted development of thromboembolic events within the first 30 days after the trauma (AUC 0.70-0.84). In conclusion, younger trauma patients mount a stronger and more dynamic in vivo thrombin response than older patients. Across age groups, in vivo thrombin generation has a strong ability to predict death and/or thromboembolic events 30 days after injury.

Impact of Stereotactic Body Radiotherapy on Thrombin Generation and Platelet Aggregation in Patients with Non-Small Cell Lung Cancer

Patients with localized non-small cell lung cancer (NSCLC) considered unfit for surgery are at substantially increased risk of venous thromboembolism. Radiotherapy may further increase this risk. We aim to investigate the impact of stereotactic body radiotherapy (SBRT) on thrombin generation and platelet aggregation. We included 110 patients with localized NSCLC treated with SBRT. Blood samples were obtained prior to SBRT, immediately after SBRT completion, and 4-6 weeks following SBRT. Ex vivo and in vivo thrombin generations were analyzed using a calibrated automated thrombogram and commercial enzyme-linked immunosorbent assays. Platelet aggregation was evaluated using multiple electrode aggregometry. No significant differences were found in ex vivo or in vivo thrombin generation between blood samples before and immediately after SBRT treatment. Platelet aggregation was lower immediately after SBRT than before SBRT (TRAP: P = 0.04 and ASPI: P = 0.02) but remained within the reference interval. SBRT did not affect in vivo and ex vivo thrombin generation or platelet aggregation. SBRT did not cause prothrombotic changes in the coagulation in this study population of SBRT-treated patients with localized NSCLC.

Haemostasis and fibrinolysis after regular high-intensity interval training in patients with coronary artery disease: a randomised controlled trial

IntroductionPatients with coronary artery disease (CAD) have prothrombotic changes compared with healthy individuals. Regular exercise reduces cardiovascular mortality in patients with stable CAD. However, the underlying mechanism for the beneficial effect is unknown. We investigated whether regular exercise would inhibit platelet aggregation and thrombin generation and increase fibrinolysis in patients with CAD.

MATERIALS AND METHODS

Patients with CAD were randomised 1:1 to a supervised high-intensity exercise training programme or standard care for 12 weeks. Blood samples were obtained at baseline and after 6 and 12 weeks. Platelet aggregation was evaluated with the Multiplate Analyser, thrombin generation using the calibrated automated thrombogram and fibrinolysis employing a clot lysis assay.

RESULTS

A total of 169 stable patients with CAD were randomised, and 142 patients (67±9 years, 83% males) completed the study; 64 in the exercise group and 78 in the standard care group. All but one patients received single antiplatelet therapy. From baseline to 12 weeks postintervention (Δ), no significant between-group differences were found in adenosine diphosphate-induced platelet aggregation (Δ-15 aggregation units (AU), AU×min, 95% CI -70 to 40 in the exercise group and Δ-26 AU×min, 95% CI -77 to 26 in the standard care group, p=0.44); endogenous thrombin potential (medians: Δ-5%, 95% CI -12 to 3 in the exercise group and Δ-6%, 95% CI -13 to 1 in the standard care group, p=0.26); nor in 50% clot lysis time (medians: Δ-9%, 95% CI -23 to 7 in the exercise group and Δ-17%, 95% CI -29 to -3 in the standard care group, p=0.60).

CONCLUSIONS

Twelve weeks of high-intensity whole-body endurance exercise did not affect platelet aggregation, thrombin generation or fibrinolysis in patients with stable CAD.

TRIAL REGISTRATION NUMBER

NCT04268992.

Blood loss during liver transplantation is a predictor of postoperative thrombosis

Liver transplantation (LT) is an effective way to cure end-stage liver diseases (ESLDs), which have generally been regarded as examples of acquired bleeding disorders. However, postoperative thrombosis after LT is recognised and remains a life-threatening complication. This study aimed to show that blood loss during LT is a predictor of postoperative thrombosis and to establish a predictive model. We analysed the medical records of all patients who underwent LT at the First Affiliated Hospital of Xi'an Jiaotong University from January 2017 to April 2019 to identify the risk factors for post-transplant thrombosis. The predictive nomogram was established based on independent predictors identified by logistic regression analysis. Blood loss during LT of ≥31.25 mL/kg can predict postoperative thrombosis, and the nomogram achieved an accurate prediction.

Inflammation and Platelet Activation After COVID-19 Vaccines - Possible Mechanisms Behind Vaccine-Induced Immune Thrombocytopenia and Thrombosis

Introduction of vaccines against COVID-19 has provided the most promising chance to control the world-wide COVID-19 pandemic. However, the adenovirus-vector based Oxford/AstraZeneca [ChAdOx1] (AZ) and Johnson & Johnson [Ad26.CoV2.S] COVID-19 vaccines have been linked with serious thromboembolic events combined with thrombocytopenia, denominated Vaccine-induced Immune Thrombocytopenia and Thrombosis (VITT). The pathogenesis of COVID-19 VITT remain incompletely understood; especially the initial events that trigger platelet activation, platelet factor (PF)4 release, complex formation and PF4 antibody production are puzzling. This is a prospective study investigating the impact of different COVID-19 vaccines on inflammation (CRP, TNF-α, IL-1β, IL-6, IL-8, IL-10), vascular endothelial activation (syndecan-1, thrombomodulin, E-selectin, ICAM-1, ICAM-3, VCAM-1), platelet activation (P-selectin, TGF-β, sCD40L) and aggregation (Multiplate^® impedance aggregometry), whole blood coagulation (ROTEM^®), thrombin generation and PF4 antibodies to reveal potential differences between AZ and mRNA vaccines in individuals without VITT. The study included 80 (55 AZ and 55 mRNA) vaccinated individuals and 55 non-vaccinated age- and gender matched healthy controls. The main findings where that both vaccines enhanced inflammation and platelet activation, though AZ vaccination induced a more pronounced increase in several inflammatory and platelet activation markers compared to mRNA vaccination and that post-vaccination thrombin generation was higher following AZ vaccination compared to mRNA vaccination. No difference in neither the PF4 antibody level nor the proportion of individuals with positive PF4 antibodies were observed between the vaccine groups. This is the first study to report enhanced inflammation, platelet activation and thrombin generation following AZ vaccination compared to mRNA vaccination in a head-to-head comparison. We speculate that specific components of the AZ adenovirus vector may serve as initial trigger(s) of (hyper)inflammation, platelet activation and thrombin generation, potentially lowering the threshold for a cascade of events that both trigger complications related to excessive inflammation, platelet and coagulation activation as observed in epidemiological studies and promote development of VITT when combined with high-titer functionally active PF4 antibodies.

Impact of frozen thawed embryo transfer in hormone substituted cycles on thrombotic risk markers

INTRODUCTION

Fertility treatment with frozen thawed embryo transfer (FET) is widely used. Women treated in artificial cycles (AC-FET) receive high doses of estrogen in contrast to natural cycles (NC-FET), where no estrogen is administered. Estrogen substitution may be associated with increased risk of thromboembolism. Our aim is therefore to characterize changes in blood coagulation parameters defined as surrogate thrombotic risk markers in women undergoing estrogen substitution during AC-FET.

MATERIALS

In our prospective cohort study, we enrolled 34 women in either: AC-FET (n = 19) or NC-FET (n = 15). Women were recruited at the Department of Obstetrics and Gynaecology, Horsens Fertility Clinic, Denmark, from August 2019 - November 2020. Blood samples were obtained at four timepoints. Thrombin generation, platelet aggregation and fibrinolysis were evaluated as thrombotic risk markers.

RESULTS

Within the AC-FET group, we found a significantly shorter lagtime (p < 0.05) and time to peak (TTP) (p < 0.001) after hormone substitution compared to baseline. Furthermore, a significantly higher mean peak (p < 0.0001) and larger endogenous thrombin potential (ETP) (p < 0.0001) was observed. When compared to the NC-FET group, women receiving AC-FET had a significantly shorter mean TTP (p < 0.005), higher mean peak (p < 0.0001) and larger ETP (p < 0.05). Additionally, we demonstrated a significantly prolonged lysis time within the AC-FET group (p < 0.001).

CONCLUSION

Our results indicate that women receiving AC-FET have a significantly increased thrombin generation which may increase the thromboembolic risk in women being estrogen substituted.

Dynamic Hemostasis and Fibrinolysis Assays in Intensive Care COVID-19 Patients and Association with Thrombosis and Bleeding-A Systematic Review and a Cohort Study

Patients admitted to the intensive care unit (ICU) with coronavirus disease 2019 (COVID-19), the infectious pathology caused by severe acute respiratory syndrome coronavirus 2, have a high risk of thrombosis, though the precise mechanisms behind this remain unclarified. A systematic literature search in PubMed and EMBASE identified 18 prospective studies applying dynamic coagulation assays in ICU COVID-19 patients. Overall, these studies revealed normal or slightly reduced primary hemostasis, prolonged clot initiation, but increased clot firmness. Thrombin generation assay parameters generally were equivalent to the control groups or within reference range. Fibrinolysis assays showed increased clot resistance. Only six studies related their findings to clinical outcome. We also prospectively included 51 COVID-19 patients admitted to the ICU. Blood samples were examined on day 1, 3-4, and 7-8 with platelet function tests, rotational thromboelastometry (ROTEM), in vivo and ex vivo thrombin generation, and clot lysis assay. Data on thrombosis, bleeding, and mortality were recorded during 30 days. Primary hemostasis was comparable to healthy controls, but COVID-19 patients had longer ROTEM-clotting times and higher maximum clot firmness than healthy controls. Ex vivo thrombin generation was similar to that of healthy controls while in vivo thrombin generation markers, thrombin-antithrombin (TAT) complex, and prothrombin fragment 1 + 2 (F1 + 2) were higher in ICU COVID-19 patients than in healthy controls. Impaired fibrinolysis was present at all time points. TAT complex and F1 + 2 levels were significantly higher in patients developing thrombosis (n = 16) than in those without. In conclusion, only few previous studies employed dynamic hemostasis assays in COVID-19 ICU-patients and failed to reveal a clear association with development of thrombosis. In ICU COVID-19 patients, we confirmed normal platelet aggregation, while in vivo thrombin generation was increased and fibrinolysis decreased. Thrombosis may be driven by increased thrombin formation in vivo.

Isovolemic filter-based therapeutic plasma-exchange with fresh frozen plasma is associated with minimal thromboelastometric changes in noncoagulopathic patients

The aim of this study was to assess the effects of isovolemic therapeutic plasma-exchange using fresh frozen plasma on coagulations parameters assessed by standard coagulation tests and rotational thromboelastometry in noncoagulopathic patients. Twenty patients who underwent isovolemic filter-based therapeutic plasma-exchange of approximately 1.5 plasma volume per session were included in the current study. Standard coagulation tests and rotational thromboelastometry (ExTEM, InTEM, FibTEM and ApTEM) were performed 30 min before and after the procedure. Isovolemic therapeutic plasma-exchange was associated with decreased fibrinogen levels (P = 0.01). Thromboelastometric assay demonstrated an increased clotting time in both ExTEM (P = 0.03) and InTEM (P = 0.01) and a decreased thrombodynamic potential index in ExTEM (P = 0.03). No significant difference in FibTEM maximum clot firmness was recorded (P = 0.41). Therapeutic plasma-exchange in noncoagulopathic patients is associated with minimal changes in thromboelastometric parameters, mainly by an increase in clotting time in both intrinsic and extrinsic pathways.

Effect of remote ischemic preconditioning on hemostasis and fibrinolysis in head and neck cancer surgery: A randomized controlled trial

Introduction

The aim of this randomized controlled trial was to investigate if remote ischemic preconditioning (RIPC) reduced platelet aggregation and increased fibrinolysis in cancer patients undergoing surgery and thereby reduced the risk of thrombosis.

Materials and methods

Head and neck cancer patients undergoing tumor resection and microsurgical reconstruction were randomized 1:1 to RIPC or sham intervention. RIPC was administered intraoperatively with an inflatable tourniquet by four cycles of 5-min upper extremity occlusion and 5-min reperfusion. The primary endpoint was collagen-induced platelet aggregation measured with Multiplate as area-under-the-curve on the first postoperative day. Secondary endpoints were markers of primary hemostasis, secondary hemostasis, and fibrinolysis. Clinical data on thromboembolic and bleeding complications were prospectively collected at 30-day follow-up. An intention-to-treat analysis was performed.

Results

Sixty patients were randomized to RIPC (n = 30) or sham intervention (n = 30). No patients were lost to follow-up. The relative mean [95% confidence interval] collagen-induced platelet aggregation was 1.26 [1.11;1.40] in the RIPC group and 1.17 [1.07;1.27] in the sham group on the first postoperative day reported as ratios compared with baseline (P = 0.30). Median (interquartile range) 50% fibrin clot lysis time was 517 (417–660) sec in the RIPC group and 614 (468–779) sec in the sham group (P = 0.25). The postoperative pulmonary embolism rate did not differ between groups (P = 1.0).

Conclusions

RIPC did not influence hemostasis and fibrinolysis in head and neck cancer patients undergoing surgery. RIPC did not reduce the rate of thromboembolic complications.

Coagulation Profile after Spontaneous Intracerebral Hemorrhage: A Cohort Study

BACKGROUND

Intracerebral hemorrhage (ICH) causes death or disability and the incidence increases with age. Knowledge of acute hemostatic function in patients with ICH without anticoagulant and antiplatelet therapy is sparse. Increased knowledge of the coagulation profile in the acute phase of ICH could improve acute treatment and recovery. We investigated coagulation at admission and changes in coagulation during the first 24hours after symptom onset.

METHODS

Enrolled were 41 ICH patients without anticoagulant or antiplatelet therapy admitted to Aarhus University Hospital, Denmark. Blood samples were collected at admission, 6, and 24hours after symptom onset. Thromboelastometry (ROTEM), thrombin generation, and thrombin-antithrombin (TAT) complex were analyzed. Clinical outcome was evaluated using the National Institute of Health Stroke Scale, the Modified Rankin Score, and mortality.

RESULTS

At admission, compared with healthy individuals, ICH patients had increased maximum clot firmness (EXTEM P < .0001; INTEM P < .0001; FIBTEM P < .0001), increased platelet maximum clot elasticity (P < .0001) in ROTEM, higher peak thrombin (P < .0001) and endogenous thrombin potential (P = .01) in thrombin generation, and elevated TAT complex levels. During 24hours after significantly, while thrombin generation showed decreased peak thrombin (P < .0001) and endogenous thrombin potential (P < .0001). Coagulation test results did not differ between patients when stratified according to clinical outcome.

CONCLUSIONS

ICH patients without anticoagulant or antiplatelet therapy demonstrated activated coagulation at admission and within 24hours after symptom onset.

Adjuvant radiotherapy does not affect hemostasis

Cancer is associated with increased risk of venous thromboembolic disease. Venous thromboembolic disease accounts for a substantial addition to morbidity and mortality rates in cancer patients and is the second leading cause of death in cancer patients, exceeded only by the underlying cancer. Only few previous studies have investigated the influence of radiotherapy on hemostasis and whether radiotherapy in itself causes an increased risk of venous thromboembolic disease. The aim was to investigate if adjuvant radiotherapy affects hemostasis after surgery and chemotherapy in patients with breast cancer. Radiotherapy consisted of either 40 Gy/15 fractions or 50 Gy/25 fractions. Blood samples were obtained from 39 consecutive women before and immediately after the first, the intermediate, and the final radiation fraction. Platelet function was measured using impedance aggregometry, and thrombin generation was determined in platelet-poor plasma using calibrated automated thrombogram. Furthermore, P-selectin, international normalized ratio, fibrinogen, activated partial thromboplastin time, coagulation factor VIII, von Willebrand factor, C-reactive protein (CRP), and soluble thrombomodulin were measured before and after radiation treatment. Platelet aggregation was within reference interval before initiation of radiotherapy, and remained unaffected during the radiation course. Neither serum P-selectin, thrombin generation, fibrinogen, coagulation factor VIII, von Willebrand factor, CRP nor thrombomodulin were substantially influenced by radiation treatment. The present study showed that radiotherapy did not affect hemostasis, neither by a single radiation dose nor during the radiation course, in early breast cancer patients receiving adjuvant radiotherapy.

Video-assisted Thoracoscopic surgery (VATS) lobectomy for lung cancer does not induce a procoagulant state

Background

Changes in the coagulation system in patients undergoing surgery for lung cancer have been sparsely investigated and the impact of the surgical trauma on the coagulation system is largely unknown in these patients. An increased knowledge could potentially improve the thromboprophylaxis regimes. The aim of this study was to assess the coagulation profile evoked in patients undergoing curative surgery by Video-Assisted Thoracoscopic Surgery (VATS) lobectomy for primary lung cancer.

Methods

Thirty-one patients diagnosed with primary lung cancer undergoing VATS lobectomy were prospectively included. The coagulation profile was assessed preoperatively and in the first two days postoperatively using a wide range of standard coagulation tests, dynamic whole blood coagulation measured by rotational thromboelastometry (ROTEM®) and thrombin generation evaluated by calibrated automated thrombography. Patients did not receive thromboprophylactic treatment. Data was analyzed using repeated measures one-way ANOVA.

Results

The standard coagulation parameters displayed only subtle changes after surgery and the ROTEM® and thrombin generation results remained largely unchanged.

Conclusions

Patients undergoing VATS lobectomy are normocoagulable in the preoperative state and a VATS lobectomy does not significantly influence the coagulation.

Trial registration

The trial is registered at ClinicalTrials.gov (Identifier: NCT01741506) and at EudraCTno. 2012–002409-23. Registered December 2012.

Prolonged targeted temperature management compromises thrombin generation: A randomised clinical trial

AIM

To investigate whether prolonged compared with standard duration of targeted temperature management (TTM) compromises coagulation.

METHODS

Comatose survivors after out-of-hospital cardiac arrest (n=82) were randomised to standard (24h) or prolonged (48h) duration of TTM at 33±1°C. Blood samples were drawn 22, 46 and 70h after attaining the target temperature. Samples were analysed for rotational thromboelastometry (ROTEM^® (EXTEM^®, INTEM^®, FIBTEM^® and HEPTEM^®)) and thrombin generation using the Calibrated Automated Thrombogram^® assay.

RESULTS

With the 22-h sample, we revealed no difference between groups in the ROTEM^® and thrombin generation results beside a slightly higher EXTEM^® and INTEM^® maximum velocity in the prolonged group (p-values≤0.04). With the 46-h sample, ROTEM^® showed no differences when using EXTEM^®; however, 11% (p<0.01) longer clotting time and 12% (p<0.01) longer time to maximum velocity were evident in the prolonged group than in the standard group when using INTEM^®. The prolonged group had reduced thrombin generation compared with the standard group as indicated by 30% longer lag time (p=0.04), 106nM decreased peak concentration (p<0.001), 36% longer time to peak (p=0.01) and 411 nM*minute decreased endogenous thrombin potential (p<0.001). With the 70-h sample, no differences in ROTEM^® results were found between groups. However, the prolonged group had reduced thrombin generation indicated by longer lag time, decreased peak concentration and longer time to peak (all p-values≤0.02) compared with the standard group.

CONCLUSION

Prolonged TTM in post-cardiac arrest patients impairs thrombin generation. ClinicalTrials.gov identifier: NCT02258360.