Novel Dielectric Coagulometer Identifies Hypercoagulability in Patients with a High CHADS2 Score without Atrial Fibrillation

Edoxaban eliminates hypercoagulability evoked by transient temperature changes in human whole blood

Background

Thrombosis is a common critical complication relating to radiofrequency catheter ablation and cryoablation. There is a possibility that high-temperature stimulation during radiofrequency ablation or low-temperature stimulation during cryoablation may affect the coagulability of blood. In this study, we aimed to determine the impacts of transient temperature stimulations on the coagulability of whole blood and to clarify if edoxaban suppressed the hypercoagulability.

Methods

Citrated blood samples were drawn from 41 healthy subjects. Some blood samples were mixed with tissue factor (TF) and several concentrations of edoxaban (50, 100, and 200 ng/mL). Blood samples were exposed to several temperature stimulations for 1 min: heat stimulation (50°C) or cryostimulation (-20°C), and compared with control (37°C). Repeated cryostimulations or sequential cryo- and heat stimulation were also applied. Coagulability of whole blood was measured using a dielectric blood coagulometry. As an index of coagulability, the end of acceleration time (EAT) was used.

Results

Both heat- and cryostimulations significantly shortened the EAT compared to the control, indicating that hypercoagulability was induced by temperature stimulations. Application of TF enhanced and extended the hypercoagulability after the temperature stimulations. Sequential application of cryo- followed by heat stimulation further enhanced the hypercoagulability of blood. Application of edoxaban increased the EAT in a concentration-dependent manner in control condition. Edoxaban at 100 or 200 ng/mL completely suppressed the shortening of EAT evoked by these temperature stimulations.

Conclusion

Transient temperature stimulations evoked hypercoagulability regardless of cryo- or heat stimulation. Edoxaban with 100 ng/mL or more eliminated this temperature-stimulated hypercoagulability.

Dielectric Blood Coagulometry for the Early Detection of Sepsis-Induced Disseminated Intravascular Coagulation: A Prospective Observational Study

OBJECTIVES

To evaluate the utility of dielectric blood coagulometry for early sepsis-induced disseminated intravascular coagulation diagnosis.

DESIGN

Single-center, prospective observational study.

SETTING

Patients with sepsis or septic shock at the Tokyo Medical and Dental University Hospital of Medicine between September 2019 and September 2020.

PATIENTS

The patients were divided into three groups according to the timing of disseminated intravascular coagulation diagnosis based on the Disseminated Intravascular Coagulation score by the Japanese Association for Acute Medicine: 1) no disseminated intravascular coagulation group, 2) late-diagnosed disseminated intravascular coagulation group: not diagnosed with disseminated intravascular coagulation on day 1 but diagnosed within 48 hours after admission, and 3) disseminated intravascular coagulation group: diagnosed with disseminated intravascular coagulation on day 1. The study evaluated 80 patients (no disseminated intravascular coagulation, 31 [38.8%]; late-diagnosed disseminated intravascular coagulation, 34 (42.5%); disseminated intravascular coagulation, 15 [18.8%]).

MEASUREMENTS AND MAIN RESULTS

We compared the clinical severity scores and mortality of the groups and assessed the correlation between the dielectric blood coagulometry-derived coagulation marker, thrombin levels, and Disseminated Intravascular Coagulation score using Spearman rank correlation. The mortality rate was 0% (0/31) in the no disseminated intravascular coagulation group, 35.3% (12/34) in the late-diagnosed disseminated intravascular coagulation group, and 33.3% (5/15) in the disseminated intravascular coagulation group. Although the Disseminated Intravascular Coagulation score on day 1 did not reflect disseminated intravascular coagulation in approximately 70% of patients who developed disseminated intravascular coagulation by day 2, dielectric clot strength measured by dielectric blood coagulometry on day 1 strongly correlated with disseminated intravascular coagulation development by day 2 (Spearman ρ = 0.824; p < 0.05) and with thrombin level on day 1 (Spearman ρ = 0.844; p < 0.05).

CONCLUSIONS

Dielectric blood coagulometry can be used to detect early-phase disseminated intravascular coagulation in patients with sepsis and is strongly correlated with thrombin levels. Larger studies are needed to verify our results for developing clinical applications.

Differential Assessment of Factor Xa Activity and Global Blood Coagulability Utilizing Novel Dielectric Coagulometry

An easy-to-use assessment for activated factor X (FXa) is lacking despite its pivotal role in the coagulation. Dielectric blood coagulometry (DBCM) was recently invented as a novel assessment tool for determining the whole blood coagulability by measuring the temporal change in the permittivity of blood. We previously reported that it could evaluate the global blood coagulability. This study aimed to apply the DBCM for assessing FXa activity and its inhibition by anticoagulants. We performed the DBCM analysis along with measurement of the FXa activity by a fluorometric assay in samples from healthy subjects, and identified a new index named maximum acceleration time (MAT) that had a correlation to the FXa activity. Next the DBCM analysis was performed using blood samples mixed with anticoagulants (unfractionated heparin, dalteparin, and edoxaban). Blood samples with three anticoagulants had different profiles of the temporal change in the permittivity, reflecting their different selectivity for FXa. We compared the MAT with the anti-FXa activity assay, and found that the prolongation of MAT was similarly correlated with the anti-FXa activity regardless of the type of anticoagulants. In conclusion, the DBCM has the possibility for evaluating the innate FXa activity and effect of anticoagulants focusing on their FXa inhibition.

Simultaneous assessment of blood coagulation and hematocrit levels in dielectric blood coagulometry

BACKGROUND

In a whole blood coagulation test, the concentration of any in vitro diagnostic agent in plasma is dependent on the hematocrit level but its impact on the test result is unknown.

OBJECTIVE

The aim of this work was to clarify the effects of reagent concentration, particularly Ca2+, and to find a method for hematocrit estimation compatible with the coagulation test.

METHODS

Whole blood coagulation tests by dielectric blood coagulometry (DBCM) and rotational thromboelastometry were performed with various concentrations of Ca2+ or on samples with different hematocrit levels. DBCM data from a previous clinical study of patients who underwent total knee arthroplasty were re-analyzed.

RESULTS

Clear Ca2+ concentration and hematocrit level dependences of the characteristic times of blood coagulation were observed. Rouleau formation made hematocrit estimation difficult in DBCM, but use of permittivity at around 3 MHz made it possible. The re-analyzed clinical data showed a good correlation between permittivity at 3 MHz and hematocrit level (R2=0.83).

CONCLUSIONS

Changes in the hematocrit level may affect whole blood coagulation tests. DBCM has the potential to overcome this effect with some automated correction using results from simultaneous evaluations of the hematocrit level and blood coagulability.

The use of dielectric blood coagulometry in the evaluation of coagulability in patients with peripheral arterial disease

Background

Platelets and coagulation proteins contribute to the development of peripheral arterial disease, especially atherosclerotic disease. Several experimental studies have proven a significant correlation between hypercoagulability and atherosclerosis. We used dielectric blood coagulometry, which was initially designed to evaluate the coagulable status, to examine the coagulability of peripheral arterial disease patients, and investigated the factors that were significantly correlated with the results.

Methods

We performed dielectric blood coagulometry in 49 peripheral arterial disease patients. In addition, we recorded the patients’ demographic information, including the presence of comorbidities, hemodynamic status, and laboratory findings. To investigate coagulability, we calculated the T_max value, which indicates the time from recalcification to maximum normalized permittivity.

Results

The T_max values of diabetes mellitus patients were significantly lower than those of non-diabetic patients (1 MHz, P = 0.010; 10 MHz, 0.011). Furthermore, the T_max value was statistically correlated with the activated partial thromboplastin time (1 MHz, ρ = 0.286, P = 0.048; 10 MHz, ρ = 0.301, P = 0.037).

Conclusions

Dielectric blood coagulometry detected the hypercoagulable status in diabetes mellitus patients, and reflected their level of coagulability, which was also evaluated by the activated partial thromboplastin time.