Epicardial adipose tissue defined by initial polytrauma CT of mechanically ventilated trauma patients: retrospective single-center cohort study to predict short-term outcomes.

PURPOSE: Epicardial adipose tissue (EAT) detected by computed tomography (CT) is associated with morbidity and mortality in patients with COVID-19 and other critical care patient cohorts, whereas their prognostic relevance in trauma patients remains unclear. The present study explored associations with four potential short-term outcomes in trauma patients. METHODS: All consecutive trauma patients requiring emergency tracheal intubation and mechanical ventilation before initial whole-body CT imaging at a level-1 trauma center over a 12-year period (2008-2019) were reanalyzed for this study. EAT was measured semiquantitatively in initial CT and analyzed regarding associations with 24-hour and 30-day mortality using Cox proportional hazard models. In survivors, associations of EAT with intensive care unit length of stay (ICU LOS) and mechanical ventilation duration were analyzed using linear regression analyses. RESULTS: Four hundred fifty-five patients (74.7% male) with a median age of 49 years, and a median injury severity score (ISS) of 26 points were analyzed. In univariable analysis, EAT index was significantly associated with 24-hour and 30-day mortality (p = 0.007, and p = 0.013, respectively). After adjustment for significant predictors age, body mass index, and ISS, no significant associations were confirmed (p = 0.622, and p = 0.903, respectively). In a subanalysis of 353 survivors, EAT index was significantly associated with ICU LOS and mechanical ventilation duration in univariable analyses (p = 0.031, and p = 0.014, respectively), but not in multivariable analyses (p = 0.81 and p = 0.46, respectively). CONCLUSION: EAT index was associated with short-term outcomes in severely injured trauma patients, which not remained significant in multivariable analysis, suggesting that its prognostic capability is limited.

Detection of direct oral anticoagulants with the diluted Russel's viper venom time.

INTRODUCTION: The activity of direct oral anticoagulants (DOAC) is important in acute clinical situations. Recent studies have suggested a strong influence of DOAC on the diluted Russel's Viper Venom Time (dRVVT). Therefore, it may be a suitable screening parameter for antithrombotic plasma activity of different DOAC. This prospective study aims to evaluate the sensitivity and specificity of dRVVT to detect residual DOAC activity at recommended plasma level thresholds. METHODS: A total of 80 patients were recruited, with 20 each treated with one of the four approved DOAC (apixaban, edoxaban, rivaroxaban or dabigatran), respectively. Blood plasma was collected before (baseline), at plasma peak time, and 6 and 12 h after DOAC. DRVVT was measured using the screen (LA1) and confirm (LA2) assay for lupus anticoagulant and compared with DOAC plasma levels. A reference range was calculated based on the dRVVT values of 61 healthy blood donors. RESULTS: All DOAC significantly prolonged the dRVVT especially at higher DOAC plasma levels. The LA1 time ≥41 s had a sensitivity ≥98% to detect edoxaban, dabigatran and rivaroxaban plasma levels ≥30 ng/mL but it was only 87% for apixaban. Sensitivity was ≥98% for all DOAC with the LA2 assay ≥36 s. The negative predictive value of a DOAC plasma level <30 ng/mL and dRVVT LA2 <36 s was 99%. CONCLUSIONS: The dRVVT confirm assay (LA2) reliably detects residual DOAC plasma levels ≥30 ng/mL and could be useful to rapidly rule out relevant DOAC activity in emergency situations and to guide treatment decisions.

Coronary artery calcification detected by initial polytrauma CT in severely injured patients: retrospective single-center cohort study.

OBJECTIVES: Coronary artery calcifications detected by computed tomography (CT) provide prognostic relevance for vascular disorders and coronary heart disease, whereas their prognostic relevance in severely injured trauma patients remains unclear. MATERIAL AND METHODS: All consecutive trauma patients requiring emergency tracheal intubation before initial CT at a level-1 trauma center and admission to the intensive care unit (ICU) over a 12-year period (2008-2019) were reanalyzed. The Weston score, a semiquantitative method to quantify coronary calcifications, was evaluated as a prognostic variable based upon whole-body trauma CT analysis. RESULTS: Four hundred fifty-eight patients (74.6% male) with a median age of 49 years, median injury severity score of 26 points, 24-h mortality rate of 7.6%, and 30-day mortality rate of 22.1% met the inclusion criteria and were analyzed. Coronary artery calcification was present in 214 patients (46.7%). After adjustment for confounding factors, the Weston score was an independent predictor for 24-h mortality (hazard ratio, HR 1.19, 95% confidence interval, CI 1.06-1.32, p = .002) and 30-day mortality (HR 1.09, 95% CI 1.01-1.17, p = .027). In a subanalysis of 357 survivors, the Weston score was significantly associated with ICU length of stay (LOS) (beta weight 0.89, 95% CI 0.3-1.47, p = .003) but not with mechanical ventilation duration (beta weight 0.05, 95% CI -0.2-0.63, p = .304). CONCLUSION: CT-detected coronary calcification was a significant prognostic factor for 24-h- and 30-day-mortality in severely injured trauma patients requiring tracheal intubation, and influenced ICU LOS in survivors.

Prognostic Relevance of Global Myocardial Work Index in Patients with Moderate Aortic Valve Stenosis.

BACKGROUND: A reduced global myocardial work index (GWI) ≤ 1951 mmHg% is associated with increased mortality in patients with severe aortic valve stenosis (AS). However, parameters predicting the outcome in patients with moderate AS are limited. Therefore, the aim of this study was to evaluate the prognostic value of the GWI in patients with moderate AS. METHODS AND RESULTS: In this prospective study, 103 patients with moderate AS (mean age 72 ± 10 years; male: 69%) underwent standardized transthoracic echocardiography. The primary endpoint was survival without an aortic valve replacement (AVR). After a median follow-up of 30 ± 5 months, 37 patients (36%) were referred for an AVR. Survival without an AVR was 96% at 12 months and 80% at 30 months (>1951 mmHg%) versus 96% and 68% (≤1951 mmHg%). A GWI ≤ 1951 mmHg% did not predict the need for an AVR (hazard ratio 1.31 (95% CI, 0.63-2.72), p = 0.49). Furthermore, there was no significant correlation between the mean GWI (1644 ± 448 mmHg%) and mean aortic valve pressure gradient (24.2 mmHg ± 6.2, p = 0.615) or effective aortic orifice area (1.24 cm2 ± 0.11, p = 0.678). There was no difference between the AVR and non-AVR groups in the occurrence of clinical symptoms. CONCLUSION: In contrast to patients with severe AS, a GWI ≤ 1951 mmHg% did not predict the need for an AVR. Further research is needed to improve the risk stratification in patients with moderate AS.

Impact of Aortic Valve Regurgitation on Doppler Echocardiographic Parameters in Patients with Severe Aortic Valve Stenosis.

BACKGROUND: Diagnosing severe aortic stenosis (AS) depends on flow and pressure conditions. It is suspected that concomitant aortic regurgitation (AR) has an impact on the assessment of AS severity. The aim of this study was to analyze the impact of concomitant AR on Doppler-derived guideline criteria. We hypothesized that both transvalvular flow velocity (maxVAV) and the mean pressure gradient (mPGAV) will be affected by AR, whereas the effective orifice area (EOA) and the ratio between maximum velocity of the left ventricular outflow tract and transvalvular flow velocity (maxVLVOT/maxVAV) will not. Furthermore, we hypothesized that EOA (by continuity equation), and the geometric orifice area (GOA) (by planimetry using 3D transesophageal echocardiography, TEE), will not be affected by AR. METHODS AND RESULTS: In this retrospective study, 335 patients (mean age 75.9 ± 9.8 years, 44% male) with severe AS (defined by EOA < 1.0 cm2) who underwent a transthoracic and transesophageal echocardiography were analyzed. Patients with a reduced left ventricular ejection fraction (LVEF < 53%) were excluded (n = 97). The remaining 238 patients were divided into four subgroups depending on AR severity, and they were assessed using pressure half time (PHT) method: no, trace, mild (PHT 500-750 ms), and moderate AR (PHT 250-500 ms). maxVAV, mPGAV and maxVLVOT/maxVAV were assessed in all subgroups. Among the four subgroups (no (n = 101), trace (n = 49), mild (n = 61) and moderate AR (n = 27)), no differences were obtained for EOA (no AR: 0.75 cm2 ± 0.15; trace AR: 0.74 cm2 ± 0.14; mild AR: 0.75 cm2 ± 0.14; moderate AR: 0.75 cm2 ± 0.15, p = 0.998) and GOA (no AR: 0.78 cm2 ± 0.20; trace AR: 0.79 cm2 ± 0.15; mild AR: 0.82 cm2 ± 0.19; moderate AR: 0.83 cm2 ± 0.14, p = 0.424). In severe AS with moderate AR, compared with patients without AR, maxVAV (p = 0.005) and mPGAV (p = 0.022) were higher, whereas EOA (p = 0.998) and maxVLVOT/maxVAV (p = 0.243) did not differ. The EOA was smaller than the GOA in AS patients with trace (0.74 cm2 ± 0.14 vs. 0.79 cm2 ± 0.15, p = 0.024), mild (0.75 cm2 ± 0.14 vs. 0.82 cm2 ± 0.19, p = 0.021), and moderate AR (0.75 cm2 ± 0.15 vs. 0.83 cm2 ± 0.14, p = 0.024). In 40 (17%) patients with severe AS, according to an EOA < 1.0 cm2, the GOA was ≥ 1.0 cm2. CONCLUSION: In severe AS with moderate AR, the maxVAV and mPGAV are significantly affected by AR, whereas the EOA and maxVLVOT/maxVAV are not. These results highlight the potential risk of overestimating AS severity in combined aortic valve disease by only assessing transvalvular flow velocity and the mean pressure gradient. Furthermore, in cases of borderline EOA, of approximately 1.0 cm2, AS severity should be verified by determining the GOA.

Comparison of quantitative flow ratio with instantaneous wave-free ratio and resting full-cycle ratio during daily routine in the catheterization laboratory.

BACKGROUND: Quantitative flow ratio (QFR) is a novel, software-based method to evaluate the physiology of coronary lesions. The aim of this study was to compare QFR with the established invasive measurements of coronary blood flow using instantaneous wave-free ratio (iFR) or resting full-cycle ratio (RFR) in daily cathlab routine. METHODS: 102 patients with stable coronary artery disease and a coronary stenosis of 40%-90% were simultaneously assessed with QFR and iFR or RFR. QFR-computation was performed by two certified experts using the appropriate software (QAngio XA 3D 3.2). RESULTS: QFR showed a significant correlation (r = 0.75, p < 0.001) to iFR and RFR. The area under the receiver curve for all measurements was 0.93 (95% confidence interval, 0.87-0.98) for QFR compared to iFR or RFR. QFR based assessment required less time with a median of 501 s (IQR 421-659 s) compared to iFR or RFR which required a median of 734 s to obtain the result (IQR 512-967 s; p < 0.001). The median use of contrast medium was similar with 21 mL (IQR 16-30 mL) for the QFR-based and 22 mL (IQR 15-35 mL) for the iFR- or RFR-based diagnostic. QFR diagnostic required less radiation. The median dose area product for QFR was 307cGycm2 (IQR 151-429 cGycm2 ) compared to 599 cGycm2 (IQR 345-1082 cGycm2 ) for iFR or RFR, p < 0.001. CONCLUSION: QFR measurements of coronary artery blood flow correlate with iFR or RFR measurements and are associated with shorter procedure times and reduced radiation dose.

Valid and Reproducible Quantitative Assessment of Cardiac Volumes by Echocardiography in Patients with Valvular Heart Diseases-Possible or Wishful Thinking?

The analysis of left ventricular function is predominantly based on left ventricular volume assessment. Especially in valvular heart diseases, the quantitative assessment of total and effective stroke volumes as well as regurgitant volumes is necessary for a quantitative approach to determine regurgitant volumes and regurgitant fraction. In the literature, there is an ongoing discussion about differences between cardiac volumes estimated by echocardiography and cardiac magnetic resonance tomography. This viewpoint focuses on the feasibility to assess comparable cardiac volumes with both modalities. The former underestimation of cardiac volumes determined by 2D and 3D echocardiography is presumably explained by methodological and technical limitations. Thus, this viewpoint aims to stimulate an urgent and critical rethinking of the echocardiographic assessment of patients with valvular heart diseases, especially valvular regurgitations, because the actual integrative approach might be too error prone to be continued in this form. It should be replaced or supplemented by a definitive quantitative approach. Valid quantitative assessment by echocardiography is feasible once echocardiography and data analysis are performed with methodological and technical considerations in mind. Unfortunately, implementation of this approach cannot generally be considered for real-world conditions.

First case report of the use of two stents following coronary artery obstruction during indirect mitral annuloplasty.

The case of a 71-year-old male with end stage heart failure and severe mitral regurgitation is presented, where percutaneous indirect mitral annuloplasty was performed. During device implantation in the coronary sinus the circumflex artery was compromised at two anatomic locations, while the mitral regurgitation was efficiently reduced. After weighing risks and alternative therapeutic options, stent implantation was chosen as bailout strategy to leave the device in place and retain the efficient MR reduction. The anatomical proximity of Cx and coronary sinus in the mitral valve plane bears the risk of circumflex artery damage during surgical and interventional mitral repair. Usually, a device exchange solves the problem of arterial flow limitation in most cases. While stent implantation remains off label use in this setting and should not be performed without critical evaluation, it has been performed successfully in similar clinical settings as well (e.g. artery stenosis by surgical suture).

Weight-adjusted dosing of tinzaparin for thromboprophylaxis in obese medical patients.

Background: The optimal dose of tinzaparin for prophylaxis in obese medical patients is not well defined. Objectives: To evaluate the anti-Xa activity in obese medical patients on tinzaparin prophylaxis adjusted for actual bodyweight. Methods: Patients with a body mass index of ≥30 kg/m2 treated with 50 IU/kg tinzaparin once daily were prospectively included. Anti-Xa and anti-IIa activity; von Willebrand factor antigen and von Willebrand activity; factor VIII activity; D-dimer, prothrombin fragments; and thrombin generation were measured 4 hours after subcutaneous injection between days 1 and 14 after the initiation of tinzaparin prophylaxis. Results: We included 121 plasma samples from 66 patients (48.5% women), with a median weight of 125 kg (range, 82-300 kg) and a median body mass index of 41.9 kg/m2 (range, 30.1-88.6 kg/m2). The target anti-Xa activity of 0.2 to 0.4 IU/mL was achieved in 80 plasma samples (66.1%); 39 samples (32.2%) were below and 2 samples (1.7%) above the target range. The median anti-Xa activity was 0.25 IU/mL (IQR, 0.19-0.31 IU/mL), 0.23 IU/mL (IQR, 0.17-0.28 IU/mL), and 0.21 IU/mL (IQR, 0.17-0.25 IU/mL) on days 1 to 3, days 4 to 6, and days 7 to 14, respectively. The anti-Xa activity did not differ among the weight groups (P = .19). Injection into the upper arm compared to the abdomen resulted in a lower endogenous thrombin potential, a lower peak thrombin, and a trend to a higher anti-Xa activity. Conclusion: Dosing of tinzaparin adjusted for actual bodyweight in obese patients achieved anti-Xa activity in the target range for most patients, without accumulation or overdosing. In addition, there is a significant difference in thrombin generation depending on the injection site.

[Clinical exam of the unconscious patient]. / Notfallmedizinische Untersuchung bei bewusstlosen Patienten ­ Schritt für Schritt.

In the setting of emergency medicine, the unconscious patient requires a special approach of clinical examination. The patient is mostly unable to communicate and cannot express any complaints. The early identification of life-threatening conditions is of utmost importance. Following the well established ABCDE scheme, we present a short algorithm, which allows the emergency physician to identify the most conditions within a few minutes.

[Coagulation diagnostics in the clinical routine-Part 1 : Evaluation of the risk of bleeding before surgery, interventions and diagnostics in bleeding diathesis]. / Gerinnungsdiagnostik im klinischen Alltag ­ Teil 1 : Evaluation des Blutungsrisikos vor Operationen, Interventionen und Diagnostik bei Blutungsneigung.

This article on coagulation diagnostics is published in two parts covering five common clinical scenarios for coagulation diagnostics. Part 1 deals with the diagnostics prior to invasive interventions and coagulation diagnostics to clarify a tendency to bleeding. The global parameters Quick and activated partial thromboplastin time are established for monitoring certain anticoagulants; however, they are not predictive with respect to the risk of bleeding prior to elective invasive interventions. In this context, disorders of primary hemostasis are frequent, which are insufficiently detected by the global parameters. Most clinical bleeding tendencies are due to acquired causes. These include anticoagulants and diseases which can be accompanied by tendency to bleeding. For coagulation tests preanalytical issues are essential in order to avoid false results. The interpretation should always be made in the context of the current physiological state.

[Coagulation diagnostics in the clinical routine-part 2 : Monitoring of anticoagulation treatment, new-onset thrombocytopenia and thrombophilia]. / Gerinnungsdiagnostik im klinischen Alltag ­ Teil 2 : Überwachung von Antikoagulanzientherapien, neu aufgetretene Thrombozytopenie und Thrombophilie.

Monitoring of vitamin K antagonist treatment with the international normalized ratio (INR) is obligatory, whereas this only applies to direct oral anticoagulants (DOAC) or low molecular weight heparin in the context of selected clinical scenarios. For DOAC the focus is on the determination of trough and peak plasma levels of the drug but for low molecular weight heparins the focus is on anti-Xa activity. The timing of blood sampling in relation to drug intake is essential for the interpretation of the results. A new-onset thrombocytopenia during hospitalization is common. The cause can frequently be identified based on the classification of the underlying disease, the day of onset and documentation of the dynamics of thrombocytopenia as well as the medication history. The importance of thrombophilia testing following a venous thromboembolism has decreased in the absence of clear therapeutic consequences; however, antiphospholipid antibody syndrome must not be overlooked as both the duration of treatment and the choice of anticoagulant depend on this.

Influence of direct oral anticoagulants on thrombin generation on Ceveron TGA.

INTRODUCTION: Monitoring of direct oral anticoagulants (DOACs) with calibrated anti-Xa assay is limited by the high intra- and interindividual variations of the test results. Thrombin generation (TG) is a global hemostatic assay that reflects the patient´s individual coagulation status. The aim of this study was to investigate the influence of DOACs on TG measured with a fully automated assay system. METHODS: All consecutive patients under apixaban and rivaroxaban coming to the outpatient coagulation center MVZ Limbach, Magdeburg, Germany between October 2017 and April 2020 were included. DOAC plasma levels were correlated with TG assessed using the fully automated Ceveron TG analyzer. RESULTS: A total of 703 rivaroxaban and 252 apixaban containing plasma samples were included. There was a significant correlation between DOAC plasma levels and all TG parameters except for lag time regarding apixaban. Time to peak and peak thrombin followed an exponential regression curve, while this was linear for the endogenous thrombin potential (ETP). Apixaban showed a lower correlation coefficient for all TG parameters compared with rivaroxaban, and thrombin generation was less influenced by apixaban than rivaroxaban at plasma levels >100 ng/ml. The sensitivity and negative predictive value of normal TG parameters for the prediction of DOAC plasma levels <30 ng/ml was >85%. CONCLUSION: The present data show a moderate predominantly nonlinear correlation between TG parameters and plasma levels of apixaban and rivaroxaban. Rivaroxaban has a stronger effect on TG than apixaban.

Left ventricular hypertrophy, diastolic dysfunction and right ventricular load predict outcome in moderate aortic stenosis.

Aims: Predictors of progression of moderate aortic valve stenosis (AS) are incompletely understood. The objective of this study was to evaluate the prognostic value of left ventricular hypertrophy (LVH), diastolic dysfunction, and right ventricular (RV) load in moderate AS. Methods and results: Moderate AS was defined by aortic valve area (AVA), peak transvalvular velocity (Vmax) or mean pressure gradient (PGmean). A total of 131 Patients were divided into two groups according to the number of pathophysiological changes (LVH, diastolic dysfunction with increased LV filling pressures and/or RV load): <2 (group 1); ≥2 (group 2). The primary outcome was survival without aortic valve replacement (AVR). After follow-up of 30 months, the reduction of AVA (-0.06 ± 0.16 vs. -0.24 ± 0.19 cm2, P < 0.001), the increase of PGmean (2.89 ± 6.35 vs 6.29 ± 7.13 mmHg, P < 0.001) and the decrease of the global longitudinal strain (0.8 ± 2.56 vs. 1.57 ± 3.42%, P < 0.001) from baseline to follow-up were significantly more pronounced in group 2. Survival without AVR was 82% (group 1) and 56% (group 2) [HR 3.94 (1.74-8.94), P < 0.001]. Survival without AVR or progression of AS was 77% (group 1) and 46% (group 2) [HR 3.80 (1.84-7.86), P < 0.001]. The presence of ≥2 pathophysiological changes predicted outcome whereas age, comorbidities, LDL-cholesterol did not. Conclusion: The presence of ≥2 pathophysiological changes is a strong predictor of outcome in moderate AS and may be useful for risk stratification, particularly for scheduling follow-up time intervals and deciding the timing of AVR.

Plasma levels do not predict thrombin generation in patients taking direct oral anticoagulants.

BACKGROUND: The antithrombotic effect of direct oral anticoagulants (DOAC) in specific clinical scenarios is difficult to assess. OBJECTIVE: This study aimed to evaluate the effect of DOAC on thrombin generation (TG) in relation to their plasma level. METHODS: Eighty patients newly started on anticoagulation were included, 20 patients for each DOAC-apixaban, edoxaban, rivaroxaban, and dabigatran. Plasma was sampled before DOAC (baseline), at plasma peak time, 6 and 12 hours after starting DOAC for quantification of drug levels and TG. RESULTS: The baseline TG before DOAC intake showed inter-individual variability. All DOACs significantly prolonged lag time (LT) and time to peak (TTP), but did not change endogenous thrombin potential (ETP). Anti-Xa inhibitors but not dabigatran reduced thrombin peak, but the effect of apixaban at plasma peak was less pronounced (factor 1.6). LT and TTP prolongation of dabigatran was lower compared to anti-Xa inhibitors. All DOACs showed a nonlinear dose-response relationship, with the greatest antithrombotic effect at lower DOAC plasma levels. The inhibition of TG parameters between baseline and peak was parallel between individual patients but the coefficient of variation of TG was lower compared to drug levels. CONCLUSION: The antithrombotic effect at DOAC peak plasma level measured by TG depends on the patient-specific baseline TG level and the drug-specific inhibition by the particular DOAC. Although peak plasma levels have a high variability, the variation of TG is lower compared to drug levels. Therefore, TG assays may be superior to plasma levels in the assessment of the intensity of anticoagulation.

Loeffler's Endocarditis: An Integrated Multimodality Approach.

Loeffler's endocarditis (LE) is the cardiac manifestation of hypereosinophilic syndrome, a rare systemic disease characterized by the sustained production of eosinophils leading to organ damage. Few data, principally by case reports, are available regarding the diagnostic workup in patients with suspected LE. Thus, we have performed a systematic search of the literature dealing with imaging in LE and propose an integrated multimodality imaging approach in the cardiac diagnostics of LE patients. The aim is to provide an updated state-of-the-art review focused on noninvasive and invasive imaging modalities for this rare and underdiagnosed disease. Standard and advanced echocardiography are typically the first cardiac imaging examinations when LE is suspected and they are also used later in follow-up for prognostic stratification and assessing response to treatment. Cardiac magnetic resonance provides a more detailed anatomical and functional evaluation of cardiac chambers, tissue characterization for the presence and extension of myocardial edema and fibrosis, and ventricular thrombi identification. Computed tomography scan and [18F]-fluoro-deoxy-glucose positron emission tomography may be helpful in selected cases to evaluate the cardiac involvement of LE as well as the other noncardiac manifestations of hypereosinophilic syndrome. Endomyocardial biopsy may be considered in patients with high clinical suspicion of LE if noninvasive imaging findings are confusing or not conclusive. The appropriate use of invasive and noninvasive imaging modalities, combining the available techniques with the patients' clinical features, will hopefully lead to early diagnosis, more accurate staging of disease, and timely treatment of LE that may prevent the irreversible myocardial damage of LE and adverse cardiovascular events.

Inhibition of thrombin generation 12 hours after intake of direct oral anticoagulants.

BACKGROUND: The residual antithrombotic activity 12 hours after intake of direct oral anticoagulants (DOACs) is of clinical relevance in the setting of bleeding or urgent surgery. OBJECTIVE: To evaluate the effects of DOACs on thrombin generation 12 hours after DOAC intake in comparison to baseline and a healthy control group. METHODS: Eighty patients were recruited, 20 patients for each approved DOAC: apixaban, edoxaban, rivaroxaban, and dabigatran. The patients were either to be put on anticoagulation for the first time or had stopped taking oral anticoagulation for at least 48 hours. Blood plasma was sampled before (baseline) and 12 hours after starting DOAC for quantification of drug levels and thrombin generation assayed using an automated system (ST Genesia). Sixty-one blood donors served as control group. RESULTS: The factor Xa inhibitors significantly increased lag time (137%-219%) and reduced thrombin peak (47%-76%) and velocity index (17%-44%) after 12 hours compared to baseline. Dabigatran showed prolongation of lag time to 133% and time to peak to 119%. All patients had residual antithrombotic activity, with reduced thrombin generation parameters 12 hours after DOAC intake compared to baseline and to the healthy control group. This effect remained significant in patients with low residual DOAC plasma levels <50 ng/mL. CONCLUSION: Thrombin generation remains reduced 12 hours after DOAC intake. While thrombin peak is particularly modified by factor Xa inhibitors, all DOACs prolong the lag time and time to thrombin peak. In the setting of bleeding or urgent surgery, the automated thrombin generation assay may assist in decision making and antidote administration.

Direct oral anticoagulant plasma levels and thrombin generation on ST Genesia system.

BACKGROUND: Monitoring of anticoagulant activity of direct oral anticoagulants (DOACs) can be necessary in special situations. DOAC plasma levels have a high inter- and intraindividual variation and do not necessarily reflect the coagulation status of the patient. Thrombin generation (TG) is a global hemostatic assay with the capacity to overcome this limitation. The aim of this study was to show correlations between DOAC plasma levels and TG parameters using the fully automated ST Genesia system. METHODS: A total of 380 blood samples (120 with apixaban, 79 with dabigatran, 79 with edoxaban, and 102 with rivaroxaban) from patients at different time points after DOAC intake were included in the analysis. DOAC plasma levels were analyzed using calibrated anti-Xa or anti-IIa tests. Thrombin generation was measured using the ST Genesia system and STG-DrugScreen reagent. RESULTS: There was a significant correlation between the drug levels of all DOACs and the TG parameters' lag time and time to peak. Peak thrombin and velocity index show a negative correlation following an exponential regression curve with all anti-Xa DOACs but not with dabigatran. Apart from a weak correlation with rivaroxaban, there was no correlation between drug levels of all other DOACs and endogenous thrombin potential. CONCLUSION: TG parameters measured with ST Genesia correlate with the drug levels of anti-Xa DOACs. Peak thrombin and velocity index are of special interest for the determination of residual anticoagulant effect at low drug levels. For dabigatran-treated patients, only lag time shows a correlation with the dabigatran plasma levels.