Comparison of Two Viscoelastic Testing Devices in a Parturient Population

Background: Viscoelastic hemostatic assays (VHAs) have become an integral diagnostic tool in guiding hemostatic therapy, offering new opportunities in personalized hemostatic resuscitation. This study aims to assess the interchangeability of ClotPro® and ROTEM® delta in the unique context of parturient women. Methods: Blood samples from 217 parturient women were collected at three timepoints. A total of 631 data sets were eligible for our final analysis. The clotting times were analyzed via extrinsic and intrinsic assays, and the clot firmness parameters A5, A10, and MCF were analyzed via extrinsic, intrinsic, and fibrin polymerization assays. In parallel, the standard laboratory coagulation statuses were obtained. Device comparison was assessed using regression and Bland-Altman plots. The best cutoff calculations were used to determine the VHA values corresponding to the established standard laboratory cutoffs. Results: The clotting times in the extrinsic and intrinsic assays showed notable differences between the devices, while the extrinsic and intrinsic clot firmness results demonstrated interchangeability. The fibrinogen assays revealed higher values in ClotPro® compared to ROTEM®. An ROC analysis identified VHA parameters with high predictive values for coagulopathy exclusion and yet low specificity. Conclusions: In the obstetric setting, the ROTEM® and ClotPro® parameters demonstrate a significant variability. Device- and indication-specific transfusion algorithms are essential for the accurate interpretation of measurements and adequate hemostatic therapy.

A ROTEM-guided algorithm aimed to reduce blood product utilization during neonatal and infant cardiac surgery

BACKGROUND

Neonates and infants undergoing cardiac surgery tend to receive high volumes of blood products. The use of rotational thromboelastometry (ROTEM^®) has been shown to reduce the administration of blood products in adults after cardiac surgery. We sought to develop a targeted administration of blood products based on ROTEM^® to reduce blood product utilization during and after neonatal and infant cardiac surgery.

METHODS

We conducted a retrospective review of data from a single center for neonates and infants undergoing congenital cardiac surgery using cardiopulmonary bypass (CPB) from September 2018-April 2019 (control group). Then, using a ROTEM^® algorithm, we collected data prospectively between April-November 2021 (ROTEM group). Data collected included age, weight, gender, procedure, STAT score, CPB time, aortic cross-clamp time, volume, and type of blood products administered in the operating room and cardiothoracic intensive care unit (CTICU). In addition, ROTEM^® data, coagulation profile in CTICU, chest tube output at 6 and 24 hours, use of factors concentrate, and thromboembolic complications were recorded.

RESULTS

The final cohort of patients included 28 patients in the control group and 40 patients in the ROTEM group. The cohort included neonates and infants undergoing the following procedures: arterial switch, aortic arch augmentation, Norwood procedure, and comprehensive stage II procedure. There were no differences in the demographics or procedure complexity between the two groups. Patients in the ROTEM^® group received fewer platelets (36 ± 12 vs. 49 ± 27 mL/kg, p 0.028) and cryoprecipitate (8 ± 3 vs. 15 ± 10 mL/kg, p 0.001) intraoperatively when compared to the control group.

CONCLUSION

The utilization of ROTEM^® may have contributed to a significant reduction in some blood product administration during cardiac surgery for infants and neonates. ROTEM^® data may play a role in reducing blood product administration in neonatal and infant cardiac surgery.

Clinical value of early assessment of hyperfibrinolysis by rotational thromboelastometry during postpartum hemorrhage for the prediction of severity of bleeding: A multicenter prospective cohort study in the Netherlands

INTRODUCTION

Coagulopathy may be the result of hyperfibrinolysis and could exacerbate bleeding following childbirth. Timely recognition of hyperfibrinolysis during the earliest stages of postpartum hemorrhage could identify women at risk of more severe blood loss who may benefit from targeted anti-fibrinolytic therapy. Rotational thromboelastometry (ROTEM^® ) is a point-of-care test that could detect hyperfibrinolysis. The aim of this study was to evaluate whether early assessment of hyperfibrinolysis by ROTEM during postpartum hemorrhage could predict progression to severe postpartum hemorrhage.

MATERIAL AND METHODS

During a prospective cohort study in the Netherlands among women with postpartum hemorrhage (total blood loss at least 1000 ml within 24 h after childbirth) ROTEM measurements were performed following 800-1500 ml of blood loss. Hyperfibrinolysis was defined as an enzymatic fibrinolysis index (ROTEM EXTEM maximum clot lysis [ML] minus the ROTEM APTEM ML) above 15%. Severe postpartum hemorrhage was defined as a composite end point of total blood loss greater than 2000 ml, transfusion of four or more units of packed cells, and/or need for an invasive intervention. The predictive value of hyperfibrinolysis for progression to severe postpartum hemorrhage was assessed by area under the receiver operating curve (AUC) and positive and negative predictive values.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02149472).

RESULTS

Of 390 women included, 82 (21%) had severe postpartum hemorrhage. Four (1%) women had thromboelastometric evidence of hyperfibrinolysis, of whom two developed severe postpartum hemorrhage. The AUC for enzymatic fibrinolysis index more than 15% for progression to severe postpartum hemorrhage was 0.47 (95% CI 0.40-0.54). Positive and negative predictive values for this index were 50.0% (95% CI 6.8-93.2) and 79.3% (95% CI 74.9-83.2), respectively.

CONCLUSIONS

Thromboelastometric evidence of hyperfibrinolysis was rare in women with postpartum hemorrhage when assessed between 800 and 1500 ml of blood loss. The clinical predictive value of viscoelastometric point-of-care testing for hyperfibrinolysis for progression to severe postpartum hemorrhage during early postpartum hemorrhage is limited.

Baseline parameters for non-activated rotational thromboelastometry tests with and without heparinase in healthy pregnant women at term gestation

OBJECTIVE

To determine the normal values for non-activated thromboelastometry parameters among pregnant women.

DESIGN

Prospective, observational study.

SETTING

Tertiary care hospital.

PATIENTS

Non-laboring women at term gestation without history of bleeding or clotting disorder or anticoagulation use.

INTERVENTIONS

Venous blood samples were collected and ROTEM® was performed using NATEM and NaHEPTEM assays.

MEASUREMENTS

Reference ranges were derived by calculating 2.5 and 97.5 percentiles for the following parameters: clotting time (CT), clot formation time (CFT), amplitude at 10 (A10) and 20 min (A20), alpha angle, maximum clot firmness (MCF), and lysis index at 30 (LI30) and 60 min (LI60). The NATEM/NaHEPTEM CT ratio was calculated to determine the baseline ratio in term pregnant women.

MAIN RESULTS

146 women were screened and 120 were enrolled. The median age was 34 years [31-36], median gestational age was 39.1 weeks [38.3-39.3], and median parity was 1 [0-2]. Median pre-delivery platelet and hematocrit levels were within the normal ranges. The reference ranges for NATEM parameters were: CT (232-759 (s)), CFT (69-243 (s)), alpha angle (50-77 (°)), A10 (44-69 (mm)), A20 (54-75 (mm)), MCF (57-77 (mm)), LI30 (100-100 (%)), LI60 (90-100 (%)). The reference ranges for NaHEPTEM parameters were: CT (224-717 (s)), CFT (66-210 (s)), alpha angle (53-77 (°)), A10 (44-67 (mm)), A20 (55-73 (mm)), MCF (58-74 (mm)), LI30 (99-100 (%)), LI60 (90-100 (%)). The NATEM to NaHEPTEM CT ratio reference range was 0.73-1.3.

CONCLUSIONS

This study is the first to our knowledge to report reference ranges for non-activated ROTEM® tests with and without heparinase in non-laboring term pregnant women. These reference ranges may serve as a baseline comparison and may be useful for future research on anticoagulation management in pregnancy.

Implementation of point-of-care ROTEM® into a trauma major haemorrhage protocol: A before and after study

OBJECTIVE

The aim of the present study was to assess transfusion practices with the implementation of a targeted viscoelastic haemostatic assay (VHA) (ROTEM®) guided coagulation management programme into a major haemorrhage protocol for trauma patients requiring ICU admission, starting from time of arrival in the ED.

METHODS

This retrospective observational study was conducted in a major trauma centre in Australia. One hundred and sixty-two trauma patients admitted to the ICU between January 2013 and December 2015 with an Injury Severity Score ≥12 and who received blood products were included: 37 in the pre-group, 48 during implementation and 77 in post-group. The primary outcome was blood and blood product administration amounts.

RESULTS

Packed red blood cell transfusion amounts did not significantly change post introduction of the ROTEM®. There was a significant increase in fibrinogen replacement between the pre- and post-groups (P < 0.001), accompanied by a reduction in the use of fresh frozen plasma (P < 0.001) and prothrombinex (P < 0.001). Platelet usage in the post-group was higher but not reaching statistical significance (P  = 0.051). Post-implementation point-of-care ROTEM® testing was able to be performed in the ED in 94.8% of cases.

CONCLUSION

Although there was no overall reduction of packed red blood cell usage, a change in the pattern of administration of other blood products was observed with the implementation of a targeted VHA (ROTEM®) guided coagulation management programme. Larger studies are needed to further define the role of early VHA testing to guide correction of trauma-induced coagulopathy and the effect on clinical outcomes.

Pathological findings in rotation thromboelastometry associated with thromboembolic events in COVID-19 patients

Background

Severe thromboembolic events are one of the major complications associated with COVID-19 infection, especially among critically ill patients. We analysed ROTEM measurements in COVID-19 patients with a severe disease course and in patients with severe sepsis.

Methods

In this study, data obtained by extended analysis of haemostasis with standard laboratory tests and thromboelastometry of 20 patients with severe course of COVID-19 were retrospectively analysed and compared with similar data from 20 patients with severe sepsis but no COVID-19.

Results

The thromboelastometry values obtained from 20 sepsis patients contained a maximum clot firmness above the normal range but among COVID-19 patients, hypercoagulability was much more pronounced, with significantly higher maximum clot firmness (FIBTEM: 38.4 ± 10.1 mm vs. 29.6 ± 10.8 mm; P  = 0.012; EXTEM: 70.4 ± 10.4 mm vs. 60.6 ± 14.8 mm; P  = 0.022). Additionally, fibrinogen levels were significantly higher among COVID-19 patients (757 ± 135 mg/dl vs. 498 ± 132 mg/dl, P < 0.0001). Furthermore, thromboelastometry showed fibrinolysis shutdown among COVID-19 patients with significantly lower maximum of lysis than among sepsis patients (EXTEM: 0.6 ± 1.2 % vs. 3.3 ± 3.7 %; P  = 0.013). Seven of 20 COVID-19 patients experienced thromboembolic events, whereas no patient in the sepsis group experienced such events.

Conclusions

ROTEM analysis showed significantly different pathological findings characterized by hypercoagulability and fibrinolysis shutdown among COVID-19 patients with a severe disease course compared to patients with severe sepsis. These abnormalities seem to be associated with thromboembolic events.

Point-of-Care Diagnostics in Coagulation Management

This review provides a comprehensive and up-to-date overview of point-of-care (POC) devices most commonly used for coagulation analyses in the acute settings. Fast and reliable assessment of hemostasis is essential for the management of trauma and other bleeding patients. Routine coagulation assays are not designed to visualize the process of clot formation, and their results are obtained only after 30-90 m due to the requirements of sample preparation and the analytical process. POC devices such as viscoelastic coagulation tests, platelet function tests, blood gas analysis and other coagulometers provide new options for the assessment of hemostasis, and are important tools for an individualized, goal-directed, and factor-based substitution therapy. We give a detailed overview of the related tests, their characteristics and clinical implications. This review emphasizes the evident advantages of the speed and predictive power of POC clot measurement in the context of a goal-directed and algorithm-based therapy to improve the patient's outcome. Interpretation of viscoelastic tests is facilitated by a new visualization technology.

Influence of Fractionation Methods on Physical and Biological Properties of Injectable Platelet-Rich Fibrin: An Exploratory Study

Injectable platelet-rich fibrin (i-PRF) has been used as an autografting material to enhance bone regeneration through intrinsic growth factors. However, fractionation protocols used to prepare i-PRF can be varied and the effects of different fractionation protocols are not known. In this study, we investigated the influence of different fractions of i-PRF on the physical and biological properties derived from variations in i-PRF fractionation preparation. The i-PRF samples, obtained from the blood samples of 10 donors, were used to harvest i-PRF and were fractioned into two types. The yellow i-PRF fractionation was harvested from the upper yellow zone, while the red i-PRF fractionation was collected from both the yellow and red zone of the buffy coat. The viscoelastic property measurements, including the clot formation time, α-angle, and maximum clot firmness, were performed by rotational thromboelastometry. The fibrin network was examined using a scanning electron microscope. Furthermore, the concentration of growth factors released, including VEGF, TGF-β1, and PDGF, were quantified using ELISA. A paired t-test with a 95% confidence interval was used. All three viscoelastic properties were statistically significantly higher in the yellow i-PRF compared to the red i-PRF. The scanning electron microscope reviewed more cellular components in the red i-PRF compared to the yellow i-PRF. In addition, the fibrin network of the yellow i-PRF showed a higher density than that in the red i-PRF. There was no statistically significant difference between the concentration of VEGF and TGF-β1. However, at Day 7 and Day 14 PDGF concentrations were statistically significantly higher in the red i-PRF compared to the yellow group. In conclusion, these results showed that the red i-PRF provided better biological properties through the release of growth factors. On the other hand, the yellow i-PRF had greater viscoelastic physical properties. Further investigations into the appropriate i-PRF fractionation for certain surgical procedures are therefore necessary to clarify the suitability for each fraction for different types of regenerative therapy.

How do external factors contribute to the hypocoagulative state in trauma-induced coagulopathy? - In vitro analysis of the lethal triad in trauma

Background

External factors following trauma and iatrogenic intervention influence blood coagulation and particularly clot formation. In particular, three external factors (in detail dilution via uncritical volume replacement, acidosis and hypothermia), in combination, referred to as the “lethal triad”, substantially aggravate the hypocoagulative state after trauma. Contribution of these external factors to the resulting hypocoagulative state in trauma and especially their influence on primary haemostasis has still not been investigated systematically.

This study aims to assess this contribution to the aggravating hypocoagulative state in trauma-induced coagulopathy (TIC) using an in vitro simulation assay. Emphasis is given to platelet contribution to clot formation and to the investigation of how platelet activation alters under the respective conditions.

Methods

To simulate the conditions of lethal triad in vitro, whole blood samples taken from five healthy volunteers were introduced to the respective conditions. Besides standard coagulation testing, thrombelastometric analysis and differentiated platelet mapping were performed.

Results

All three simulated conditions induced significant impairments of clot formation (clot formation time, CFT; α -angle) and propagation (maximum clot firmness, MCF; Diameter A5-A25), with the highest impact under hypothermia and dilution. Consistently, lethal triad resulted in an additive effect of all conditions. None of the simulated conditions induced a statistically relevant change in coagulation initiation assessed by EXTEM and FIBTEM thrombelastometry.

Platelet contribution to clot formation decreased gradually under the respective conditions, reaching statistical significance for simulated dilution, and attaining its greatest extent under the conditions of lethal triad (Δtrias/baseline 0.59; p = 0.01). Consistent, reduced CD62 expression levels were observed under experimental acidosis (Δacidosis/baseline 0.32; p = 0.006), dilution (Δdilution/baseline 0.34; p = 0.01) and lethal triad (Δlethal triad/baseline 0.24; p = 0.01).

Conclusion

The respective external factors of lethal triad play a pivotal role in the development of coagulopathy, essentially influencing the kinetics of clot formation, and to a varying extent clot diameter, as measured by thrombelastometry. Moreover, impairment of platelet function under the conditions of lethal triad plays a key role in the pathophysiology of TIC, resulting in reduced responsiveness to stimulation with ADP that might also be present after trauma. Our data indicate that impairment of primary haemostasis contribute to the hypocoagulative state in TIC after trauma aggravated by external factors of lethal triad.

Detecting clinically relevant rivaroxaban or dabigatran levels by routine coagulation tests or thromboelastography in a cohort of patients with atrial fibrillation

BACKGROUND

Traditional coagulation tests are included in emergency guidelines for management of patients on direct oral anticoagulants (DOACs) who experience acute bleeding or require surgery. We determined the ability of traditional coagulation tests and fast whole blood thromboelastography (ROTEM®) to screen for anticoagulation activity of dabigatran and rivaroxaban as low as 30 ng/mL.

METHODS

One hundred eighty-four citrated blood samples (75 dabigatran, 109 rivaroxaban) were collected from patients with non-valvular atrial fibrillation (NVAF), to perform screening tests from different manufacturers, (diluted, D) PT, aPTT, TT and ROTEM®. The activity of DOACs was quantitatively determined by clot detection assays: Hemoclot DTT and DiXaI test (Biophen), on CS2100 (Siemens). The clotting time (CT) of INTEM and EXTEM ROTEM® (Werfen) were used as test parameters.

RESULTS

Dabigatran, ≥ 30 ng/mL, was accurately detected by five coagulation tests: APTT Actin FSL (93%), PT Neoplastin (93%), APTT Cephascreen, Thromboclotin, and Thrombin (all 100%), but not by PT Innovin (49%). CT-EXTEM (91%) was sufficiently sensitive, but not CT-INTEM (52%). APTT Cephascreen and Thrombin showed good linearity (R2 = 0.71,R2 = 0.72). For the other tests linearity was moderate to poor. Rivaroxaban was accurately detected by PT Neoplastin (98%) and less so by APTT Cephascreen (85%). In addition, rivaroxaban was also accurately detected by CT-INTEM (96%). PT Neoplastin showed good linearity (R2 = 0.81), all other tests had moderate to poor linearity.

CONCLUSION

In patients with NVAF, the ability of routine coagulation tests to detect the presence of significant levels of DOACs is test and reagent dependent. CT-INTEM and CT-EXTEM may be fast whole blood alternatives.

TRIAL REGISTRATION

The Institutional Review Board of the MUMC approved this study (December 2011, project number 114069).

Fibrinogen Early In Severe Trauma studY (FEISTY): study protocol for a randomised controlled trial

BACKGROUND

Haemorrhage is a leading cause of death in severe trauma. Fibrinogen plays a critical role in maintaining haemostasis in traumatic haemorrhage. Early fibrinogen replacement is recommended by several international trauma guidelines using either fibrinogen concentrate (FC) or cryoprecipitate (Cryo). There is limited evidence to support one product over the other with widespread geographic and institutional variation in practice. This pilot trial is the first randomised controlled trial comparing FC to Cryo in traumatic haemorrhage.

METHODS/DESIGN

The Fibrinogen Early In Severe Trauma studY (FEISTY) is an exploratory, multicentre, randomised controlled trial comparing FC to Cryo for fibrinogen supplementation in traumatic haemorrhage. This trial will utilise thromboelastometry (ROTEM®) to guide and dose fibrinogen supplementation. The trial will recruit 100 trauma patients at four major trauma centres in Australia. Adult trauma patients with evidence of haemorrhage will be enrolled on arrival in the trauma unit and randomised to receiving fibrinogen supplementation with either FC or Cryo. The primary outcome is the differential time to fibrinogen supplementation. There are a number of predetermined secondary outcomes including: effects of the intervention on plasma fibrinogen levels, feasibility assessments and clinical outcomes including transfusion requirements and mortality.

DISCUSSION

The optimal method for replacing fibrinogen in traumatic haemorrhage is fiercely debated. In this trial the feasibility and efficacy of fibrinogen supplementation using FC will be compared to Cryo. The results of this pilot study will facilitate the design of a larger trial with sufficient power to address patient-centred outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02745041 . Registered 4 May 2016.

Thromboelastometry guided fibrinogen replacement therapy in cardiac surgery: a retrospective observational study

This retrospective, observational study compared the impact of a point-of-care rotational thromboelastometry (ROTEM^®) method versus conventional bleeding management in terms of postoperative (24-h) blood loss, intraoperative and postoperative (24-h) transfusion requirement and length of stay in the postoperative intensive care unit (ICU) in patients undergoing cardiac surgery. Forty consecutive patients undergoing cardiac surgery under ROTEM^®-guided hemostatic management were enrolled; the control population included 40 selected patients undergoing similar interventions without ROTEM^® monitoring. Significantly more patients in the thromboelastometry group versus the control group received fibrinogen (45 vs 10 %; p < 0.0001), while fewer received a transfusion (40 vs 72.5 %; p < 0.0033). Compared with control group patients, those in the thromboelastometry group had less postoperative bleeding (285 vs 393 mL; p < 0.0001), a shorter time from cardiopulmonary bypass discontinuation to skin suture (79.3 vs 92.6 min; p = 0.0043) and a shorter stay in the ICU (43.7 vs 52.5 h; p = 0.0002). In our preliminary experience, ROTEM^®-guided bleeding management was superior to conventional management of bleeding in patients undergoing complex cardiac surgery with cardiopulmonary bypass in terms of reduced postoperative blood loss, transfusion requirement, and length of ICU stay.

Point of care and factor concentrate-based coagulation algorithms

In the last years it has become evident that the use of blood products should be reduced whenever possible. There is increasing evidence regarding serious adverse events, including higher mortality and morbidity, related to transfusions. The use of point of care (POC) devices integrated in algorithms is one of the important mechanisms to limit blood product exposure. Any type of algorithm, especially the POC-based ones, allows goal-directed transfusions of blood products and even better targeted factor concentrate substitutions. Different types of algorithms in different surgical settings (cardiac surgery, trauma, liver surgery etc.) have been established with growing interest in their use as they offer objective therapy for management and reduction of blood product use. The use of POC devices with evidence-based algorithms is important in the bleeding patient independent of its origin (traumatic vs. surgical). The use of factor concentrates compared to the classical blood products can be cost-saving, beneficial for the patient, and in agreement with the WHO-requested standard of care. The empiric and uncontrolled use of blood products such as fresh frozen plasma, red blood cells, and platelets without POC monitoring should no longer be followed with regard to actual evidence in literature. Furthermore, the use of factor concentrates may provide better outcomes and potential for cost saving.