Browsing by Subject "ANTICOAGULANTS"

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  • Huhtakangas, Juha; Tetri, Sami; Juvela, Seppo; Saloheimo, Pertti; Bode, Michaela K.; Hillbom, Matti (2011)
  • Helin, Tuukka A.; Virtanen, Lauri; Manninen, Mikko; Leskinen , Jarkko; Leppilahti, Juhana; Joutsi-Korhonen, Lotta; Lassila, Riitta (2017)
    Factor Xa inhibitors (FXaI) apixaban and rivaroxaban are used for thromboprophylaxis after major elective orthopaedic surgery. Because few patient sample studies exist, we postoperatively assessed patients undergoing unilateral total hip arthroplasty, including 22 treated with apixaban (2.5 mg BID) and 20 treated with rivaroxaban (10 mg OD). We collected blood samples before and 3 h after drug intake at 4 time points, preoperatively, as well as on day 1, week 1 (day 2-8) and day 28 post-operation. APTT and PT were immediately analysed. Calibrated anti-FXa activity, Russel's Viper Venom Time (RVVT) and thrombin generation (TG; Calibrated Automated Thrombogram(A (R))) captured the effects of FXaI on coagulation and TG. APTT and PT remained within the reference interval throughout, and did not correlate with FXaI levels (PT R-2 = 0.44, APTT R-2 = 0.07). Mean apixaban concentration at the peak varied by eightfold (19-153 ng/mL), but rivaroxaban only by 1.5-fold (111-183 ng/mL). Rivaroxaban, but not apixaban prolonged RVVT at peak levels. Both FXaIs had a prolonged lag time of TG (p <0.001). Rivaroxaban decreased ETP peak at all time points and reached a minimum at day 28 (540 nM/min at rivaroxaban 184 ng/mL, p <0.001), while rivaroxaban trough levels were low and ETP values normal. However, with apixaban, after an initial decrease, ETP did not differ between peak and trough levels until decreasing on day 28 at peak (990 nM/min at apixaban 112 ng/mL, p = 0.005). In conclusion, due to different dosing and pharmacology rivaroxaban and apixaban distinctly inhibited TG under postoperative conditions.
  • Ljungkvist, Marcus; Strandberg, Karin; Berntorp, Erik; Chaireti, Roza; Holme, Pål Andre; Larsen, Ole Halfdan; Lassila, Riitta; Jouppila, Annukka; Szanto, Timea; Zetterberg, Eva (2019)
    Introduction The thrombin generation assay-calibrated automated thrombogram (TGA-CAT) method is used to measure the overall coagulation capacity in plasma. However, the method is still considered to be a research tool, mainly because of its' lack of standardization. Aim Our study aimed to further raise the standardization level for the TGA-CAT method by evaluating a detailed standardization protocol and three reference plasmas' (RP)s ability to normalize results. Methods Six Nordic centres participated in the study, and with input from all centres a detailed laboratory standardization protocol based on the TGA-CAT manual of the manufacturer was established. Three types of plasma, hypo-,normal and hypercoagulable plasma were assessed. Three commercial lyophilized RPs were used for normalization of data. All samples were aliquoted at the Malmo centre and sent frozen at -20C to participating centres. Results Before normalization, all results under all testing conditions showed inter-laboratory coefficient of variability of 10% or lower except for endogenous thrombin potential (12%) and peak (14%) in hypo-plasma with 1 pmol/L tissue factor as starting agent. Successful normalization, improving variability in results, was obtained with two of the three evaluated RPs (HemosIL RP and Affinity RP). Conclusion With our standardization concept, we were able to produce TGA-CAT results as robust as standard coagulation assays used in the routine laboratories. Normalization with HemosIL RP may be considered in populations with low or unknown coagulability, while when analysing plasma samples from populations where hypercoagulability is known or suspected, normalization with Affinity RP may be preferred.
  • Lindsberg, Perttu J.; Toivonen, Lauri; Diener, Hans-Christoph (2014)