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- Bozic-Mijovski, M, et al.
(författare)
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Diluted thrombin time reliably measures low to intermediate plasma dabigatran concentrations
- 2016
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Ingår i: Annals of clinical biochemistry. - : SAGE Publications. - 1758-1001. ; 53:4Pt 4, s. 446-451
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Tidskriftsartikel (refereegranskat)abstract
- Direct oral anticoagulant dabigatran was first introduced as a fixed-dose drug without routine coagulation monitoring, but current recommendations suggest that diluted thrombin time can be used to estimate plasma drug level. The aim of this study was to assess a diluted thrombin time assay based on the same thrombin reagent already used for traditional thrombin time measurements that reliably measure low to intermediate plasma dabigatran levels. Methods We included 44 patients with atrial fibrillation who started treatment with dabigatran 150 mg (23 patients) or 110 mg (21 patients) twice a day. Blood samples were collected at baseline (no dabigatran) and 2–4 weeks after the beginning of dabigatran therapy at trough and at peak. Plasma dabigatran levels were measured with diluted thrombin time and compared to liquid chromatography with tandem mass spectrometry as the reference method. The performance of the diluted thrombin time was compared to Hemoclot® Thrombin Inhibitor and Ecarin Chromogenic Assay. Results In ex vivo plasma samples, diluted thrombin time highly correlated with the liquid chromatography with tandem mass spectrometry (Pearson’s R = 0.9799). In the low to intermediate range (dabigatran concentration ≤ 100 µg/L) diluted thrombin time correlated significantly more closely to the liquid chromatography with tandem mass spectrometry (R = 0.964) than Hemoclot® Thrombin Inhibitor (R = 0.935, p = 0.05) or Ecarin Chromogenic Assay (R = 0.915, p < 0.01). It was also the only functional assay without any significant bias in the low to intermediate range. Both trough and peak diluted thrombin time values were similar to liquid chromatography with tandem mass spectrometry. Conclusion We conclude that the diluted thrombin time assay presented in this study reliably detects dabigatran and that it is superior to the Hemoclot® Thrombin Inhibitor assay in the low to intermediate range.
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- Mavri, A, et al.
(författare)
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Apixaban concentration variability and relation to clinical outcomes in real-life patients with atrial fibrillation
- 2021
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 13908-
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Tidskriftsartikel (refereegranskat)abstract
- In some clinical situations, measurements of anticoagulant effect of apixaban may be needed. We investigated the inter- and intra-individual apixaban variability in patients with atrial fibrillation and correlated these results with clinical outcome. We included 62 patients receiving either 5 mg (A5, n = 32) or 2.5 mg (A2.5, n = 30) apixaban twice-daily. We collected three trough and three peak blood samples 6–8 weeks apart. Apixaban concentration was measured by liquid chromatography-tandem mass-spectrometry (LC–MS/MS) and by anti-Xa. Patients on A2.5 were older, had lower creatinine clearance, higher CHA2DS2VASc (4.7 ± 1.0 vs. 3.4 ± 1.7) and lower trough (85 ± 39 vs. 117 ± 53 ng/mL) and peak (170 ± 56 vs. 256 ± 91 ng/mL) apixaban concentrations than patients on A5 (all p < 0.01). In patients on A5, LC–MS/MS showed a significant difference between through levels and between peak levels (p < 0.01). During apixaban treatment, 21 patients suffered bleeding (2 major). There was no association between bleeding and apixaban concentrations or variability. Four patients who suffered thromboembolic event had lower peak apixaban concentrations than patients without it (159 ± 13 vs. 238 ± 88 ng/mL, p = 0.05). We concluded, that there was a significant intra- and inter-individual variability in apixaban trough and peak concentrations. Neither variability nor apixaban concentrations were associated with clinical outcomes.
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- Mijovski, MB, et al.
(författare)
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The in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation
- 2021
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 5920-
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Tidskriftsartikel (refereegranskat)abstract
- Dabigatran interferes with many coagulation tests. To overcome this obstacle the use of idarucizumab as an in vitro antidote to dabigatran has been proposed. The aim of this study was to test the effect of idarucizumab as an in vitro antidote to dabigatran in ex vivo plasma samples from routine clinical patients examined by a thrombin generation assay (TGA). From 44 patients with atrial fibrillation five blood samples were collected. Thrombin generation was measured in all samples before and after the addition of idarucizumab. When idarucizumab was added to baseline plasma (no dabigatran), it caused a significantly shorter Lag Time and Time to Peak Thrombin, and a higher Peak Thrombin and Endogenous Thrombin Potential (ETP) of TGA. Similar results were obtained when idarucizumab was added to dabigatran-containing plasma, with TGA parameters comparable to baseline + idarucizumab plasma, but not to baseline plasma. In summary, our study showed that in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation. The use of idarucizumab to neutralize dabigatran in patient plasma samples as well as the clinical relevance of in vitro increased thrombin generation induced by idarucizumab needs further investigation.
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