Rapid determination of anticoagulating effects of dabigatran in whole blood with rotational thromboelastometry and a thrombin-based trigger

Essentials A rapid test to detect thrombin inhibition by dabigatran would be valuable in acute situations. A thrombin-based trigger was applied in whole blood using rotation thromboelastometry. Effects of dabigatran were assessed in vitro and in samples from patients on dabigatran. The test produced data rapidly and was sensitive to dabigatran concentrations from 20 to 500 ng mL-1 . SUMMARY: Background Rapid determination of the anticoagulant effect of dabigatran is essential in emergency situations. Objective To study a viscoelastic test (rotational thromboelastometry [ROTEM]) for rapid determination of dabigatran effects in whole blood samples. Method ROTEM measurements were performed with comparison of two triggers (thrombin-based versus the commercial tissue factor-based trigger Ex-tem) in samples from 10 healthy donors spiked with dabigatran (20-500 ng mL-1 ) and in samples from 35 patients receiving dabigatran treatment; 10 healthy subjects served as controls. Clotting time (CT) and the difference in CT without versus with addition of the dabigatran antidote idarucizumab (CTdiff ) were measured. Addition of idarucizumab reveals the contribution of dabigatran to ROTEM measurements and its potential reversibility. Results In vitro studies showed that thrombin CT and thrombin CTdiff were more sensitive than Ex-tem CT and Ex-tem CTdiff in detecting dabigatran in whole blood samples. In patient samples, when thrombin CT and thrombin CTdiff were used, it was possible to detect dabigatran with a cut-off of dabigatran at 20 ng mL-1 , whereas, when Ex-tem CT and Ex-tem CTdiff were used, the method was less sensitive. Data from patient samples were obtained within 15 min of blood sampling. Conclusions ROTEM CT with a thrombin-based trigger is more sensitive to dabigatran effects than Ex-tem CT, and detects anticoagulant effects of drug concentrations in the low-very low therapeutic range. Analysis with idarucizumab (CTdiff ) reveals dabigatran-specific effects. As data are rapidly obtained, this method could, with further development and validation of its performance, be suitable for detecting clinically significant dabigatran effects in emergency situations.

A single test to assay warfarin, dabigatran, rivaroxaban, apixaban, unfractionated heparin, and enoxaparin in plasma

Essentials Simple and fast assaying of different anticoagulants (ACs) is useful in emergent situations. We used highly diluted prothrombin time (dPT) or highly diluted Fiix-PT (dFiix-PT) to assay ACs. Both tests could quantify target specific anticoagulants and warfarin anticoagulation. Improved results were consistently observed with the dFiix-PT compared with the dPT.

SUMMARY

Background Assaying anticoagulants is useful in emergency situations or before surgery. Different specific assays are currently needed depending on the anticoagulant. Objectives We hypothesized that levels of warfarin, dabigatran, rivaroxaban, apixaban, and heparins could be measured with use of the diluted prothrombin time (dPT) and diluted Fiix-PT (dFiix-PT), using highly diluted thromboplastin (TP). The latter test is affected only by reduced levels of active factors II and X but corrects test plasma for other deficiencies Methods Increasing TP dilutions were used to identify suitable dilutions to measure dabigatran, rivaroxaban, apixaban, unfractionated heparin (UFH), and enoxaparin. Calibrators containing known amounts of direct oral anticoagulants (DOACs) were used to make standard curves. Citrated plasma samples were obtained from patients taking warfarin or DOACs with known drug concentrations as determined by specific assays. Results The dFiix-PT at a TP dilution of 1:1156 could be used to measure all of the drugs tested at therapeutic concentrations except for fondaparinux. The dPT achieved the same but required two TP dilutions (1:750 and 1:300). The warfarin effect could be assessed by using dFiix-PT at 1:1156 with a PT ratio identical to the international normalized ratio. Six different TPs yielded similar results, but two were less sensitive. Dabigatran, rivaroxaban, and apixaban could be accurately measured in patient samples using both dilute PT assays, but a better correlation was consistently observed between the dFiix-PT and specific assays than with the dPT. Conclusion The dFiix-PT using a single dilution of TP may be suitable to assess the anticoagulant effects of warfarin, dabigatran, rivaroxaban, apixaban, heparin, and enoxaparin.

Pain from donor site after anterior cervical fusion with bone graft: a prospective randomized study with 12 months of follow-up

INTRODUCTION

Harvesting bone graft from the iliac crest in spinal fusion surgery is a widely used technique. However, complications can occur and there are also reports of patients with persistent graft site pain after surgery. The aim of this study was to evaluate pain from the donor site (DS) over time, and register associated complications and if it affected health-related quality of life (HRQoL).

MATERIAL AND METHODS

One hundred and seven patients participating in an RCT between two different methods of reconstruction after cervical decompression were included in this study. One group underwent surgery with bone graft (BG) from the iliac crest and the other with no bone graft (NBG). All patients were evaluated concerning pain at DS and HRQoL preoperatively, at 4 weeks, 3 months and 1 year. Pain was evaluated with visual analog scale (VAS) and HRQoL with EQ-5D.

RESULTS

A statistically significant difference was found at all times of follow-up in the BG group compared to preoperative levels and the NBG group. The VAS levels at follow-ups at 3 months and 1 year were however of questionable clinical importance. Two patients in the BG group had superficial wound infections postoperatively and five patients still had sensory disturbance in the area of graft site at 12 months. No major complications were registered. No difference could be seen in EQ-5D at any time of follow-up between the groups.

CONCLUSION

Harvesting of iliac crest bone graft is associated with significant pain. However, at 3 months postoperatively, the negative effect of clinical importance seemed to have disappeared compared to when no bone graft was harvested. The pain from bone graft harvesting does not seem to affect the quality of life at 4 weeks postoperatively and onward.

Risk factors for myocardial infarction with normal coronary arteries and myocarditis compared with myocardial infarction with coronary artery stenosis

The interest and awareness of myocardial infarction with normal coronary arteries (MINCA) have increased recently due to the frequent use of coronary angiography, the description of Takotsubo stress cardiomyopathy, and new sensitive troponin analyses. The prevalence of MINCA in all patients with myocardial infarction (MI) was registered during a 3-month period in the Stockholm metropolitan area in Sweden. The results showed that MINCA is more common than previously thought (7%) and affecting one third of every woman with MI. Patients with myocarditis were younger and more often presented with signs of inflammation such as elevated C-reactive protein and fever. Myocarditis constitutes an important differential diagnosis for coronary artery disease. There is a need for larger studies of MINCA, including investigation with cardiac magnetic resonance imaging, to establish prevalence and pathological process in this important subgroup of MI.