Ulf Schött

Background/Objectives: Vitamin K-dependent proteins (VKDPs) all commonly possess specially modified γ-carboxyglutamic acid residues created in a vitamin K-dependent manner. Several liver-derived coagulation factors are well characterised VKDPs. However, much less is known about extrahepatic VKDPs, which are more diverse in their molecular structures and functions, and some of which have been implicated in inflammatory disorders. Vitamin K metabolism was shown to be impaired in critically ill patients, in whom systemic inflammation and sepsis are common features. Therefore, the aim of this study was to investigate the effect of vitamin K administration to these patients on their circulating levels of selected VKDPs. A particular novelty of this study was the measurement of specifically carboxylated forms of these proteins in addition to their overall levels. Methods: Blood samples were taken from 47 patients in the intensive care unit before and approximately 24 h after intravenous vitamin K1 (10 mg) administration, and proteins were analysed by specific immunoassay. Results: Vitamin K1 induced increases in plasma levels of carboxylated osteocalcin and total Gas6 (p = 0.0002 and p = 0.0032, respectively). No changes were detected in levels of carboxylated Gas6 or PIVKA-II (undercarboxylated prothrombin), although the latter positively correlated with undercarboxylated osteocalcin (r = 0.38). Conclusion: Injected vitamin K1 increases the blood levels of two distinct VKDPs in critically ill patients, both of which have been implicated in inflammation regulation, including the increased carboxylation of one of them.

Direct oral anticoagulants (DOAC) are increasingly common, with bleeding events associated with elevated plasma concentrations. Rotational thromboelastometry (ROTEM), a point-of-care tool for assessing secondary hemostasis, has demonstrated a correlation with increasing concentrations of DOAC. However, previous studies have only partially explored this relationship. The primary aim in the current study was to investigate the impact of increasing rivaroxaban concentrations on clotting time (CT) in the EXTEM assay. The secondary aims were to investigate the impact of increasing rivaroxaban concentrations on clot formation time (CFT) and α-angle (AA) and to investigate the impact of increasing concentrations of dabigatran and apixaban on CT, CFT and AA. Blood from 12 healthy volunteers was spiked to anticipated concentrations of rivaroxaban, dabigatran and apixaban at 0, 50, 100, 200, 500 and 1000 µg/L each. Blood with these varying concentrations was analyzed in four different ROTEM assays and CT, CFT and AA were extracted. CT increased linearly with increasing concentrations of all three DOACs. Rivaroxaban and dabigatran spiked blood showed an increase in CT-EXTEM for the 200-1000µg/L concentrations, compared to baseline, and apixaban for the 500-1000 µg/L concentrations. CFT and AA were affected only in supratherapeutic concentrations for all tested DOACs and primarily in the INTEM assay. Among the tested DOACs, apixaban demonstrated the least impact on CT across all assays. In conclusion, ROTEM-derived CT measurements can serve as surrogate markers for DOAC concentrations.

Background: Hypothermia and acidosis individually inhibit haemostasis. We designed this study with the aim to investigate whether rivaroxaban combined with hypothermia or acidosis exhibit synergistic inhibitory effects on haemostasis using ROTEM^®. Methods: Patients with a clinical indication to start rivaroxaban treatment were prospectively included. Blood samples were collected before initiation of treatment and the day after. All blood samples were in vitro modified with respect to temperature (incubated and analysed at 28, 33, 37 and 40 degrees Celsius (°C)) and pH (6.8, 7.0, 7.2 and 7.4). The temperature and acidosis effects on the ROTEM EXTEM variables clotting time (CT), clot formation time (CFT) and alpha-angle (AA) were measured along with the individual effect of rivaroxaban on the same variables. The additive effect was calculated. The observed (potential synergistic) effects for the temperature and pH modified rivaroxaban samples on the same ROTEM variables, were registered. Differences between the additive and observed (potential synergistic) effects were analysed using matched non-parametric hypothesis testing. Results: In total, 13 patients were included. Hypothermia and rivaroxaban exhibited a synergistic effect on CT at 28 °C (p = 0.0002) and at 33 °C (p = 0.0007). The same applied for acidosis at pH 6.8 (p = 0.003) and pH 7.0 (p = 0.003). There were no signs of synergistic effects of rivaroxaban and temperature or acidosis on CFT. In AA there were signs of synergism at 28 °C (p = 0,001), but not at other tested temperatures or pH levels. Conclusions: The combination rivaroxaban together with hypothermia or acidosis demonstrated inhibitory synergistic effects on haemostasis. Trial registration: The study was retrospectively registered 2023-03-01 at ClinTrials.gov with NCT05669313.

Background: The use of viscoelastic tests is becoming increasingly popular. There is a paucity of validation of the reproducibility of varying coagulation states. Therefore, we aimed to study the coefficient of variation (CV) for the ROTEM EXTEM parameters clotting time (CT), clot formation time (CFT), alpha-angle and maximum clot firmness (MCF) in blood with varying degrees of coagulation strength. The hypothesis was that CV increases in states of hypocoagulability.Methods: Critically ill patients and patients subjected to neurosurgery at a university hospital during three separate periods were included. Each blood sample was tested in eight parallel channels, yielding the CVs for the tested variables. In 25 patients, the blood samples were analysed both at baseline and after dilution with albumin 5%, as well as after being spiked with fibrinogen, simulating weak and strong coagulation.Results: In total, 225 unique blood samples were collected from 91 patients. All samples were analysed in eight parallel ROTEM channels, resulting in 1,800 measurements. In hypocoagulable samples, defined as those with values outside the normal reference range, the CV of CT was higher (median (interquartile range)) (6.3% (5.1–9.5)) than for normocoagulable samples (5.1% (3.6–7.5)),p < 0.001. CFT showed no difference (p = 0.14), while the CV of alpha-angle was higher in hypocoagulable samples (3.6% (2.5–4.6)) than in normocoagulable samples (1.1% (0.8–1.6),p < 0.001. The CV of MCF was higher in hypocoagulable samples (1.8% (1.3–2.6)) than in normocoagulable samples (1.2% (0.9–1.7)),p < 0.001. The CV ranges for the different variables were as follows: CT: 1.2%–37%, CFT: 1.7%–30%, alpha-angle: 0.0%–17% and MCF: 0.0%–8.1%.Conclusions: CVs for the EXTEM ROTEM parameters CT, alpha-angle, and MCF increased in hypocoagulable blood compared to blood with normal coagulation, confirming the hypothesis for CT, alpha-angle, and MCF but not for CFT. Furthermore, the CVs for CT and CFT were much higher than those for alpha-angle and MCF. The results demonstrate that EXTEM ROTEM results from patients with weak coagulation should be interpreted with the notion of limited precision and that procoagulative treatment, based only on ROTEM EXTEM, should be given with some caution.

Growth arrest-specific gene 6 protein (Gas6) is avitamin K-dependent tissue bound protein. Gas6 has been shown to promote growth and therapy resistance among different types of cancer as well as thromboembolism. The aim of this prospective screening study: ClinicalTrials.gov; Identifier: NTC3782025, was to evaluate the effects of intravenously administered vitamin K1 on Gas6 and its soluble (s)Axl receptor plasma levels in intensive care patients. Vitamin K1 was intravenously injected in non-warfarin treated patients with prolonged Owren prothrombin time international normalized ratio (PT-INR) > 1.2 and blood samples were retrieved before and 20–28 h after injection. Citrate plasma samples from 52 intensive care patients were analysed for different vitamin K dependent proteins. There was a significant, but small increase in median Gas6. Only one patient had a large increase in sAxl, but overall, no significant changes in sAxl Gas6 did not correlate to PT-INR, thrombin generation assay, coagulation factors II, VII, IX and X, but to protein S and decarboxylated matrix Gla protein (dp-ucMGP). In conclusion, there was a small increase in Gas6 over 20–28 h. The pathophysiology and clinical importance of this remains to be investigated. To verify a true vitamin K effect, improvement of Gas6 carboxylation defects needs to be studied.

The aim of this study was to evaluate the effects of vitamin K1 on various vitamin K-dependent proteins in critically ill patients with prolonged Owren PT. We included critically ill non-bleeding adult patients without liver failure or anticoagulation treatment, with Owren PT > 1.2, who were prescribed intravenous vitamin K1. Blood was drawn at baseline and at 20–28 h after vitamin K1 administration. At both time points, we measured various vitamin K-dependent proteins and coagulation assays. ClinicalTrials.gov; Identifier: NTC3782025. In total, 52 patients were included. Intravenous vitamin K1 reduced Owren PT, Quick PT, protein induced by vitamin K absence/antagonist-II and desphospho-uncarboxylated matrix Gla protein (dp-ucMGP), but not to normal levels. Concomitantly, there were increases in thrombin generation and the activity of coagulation factors II, VII, IX and X that was only counteracted with a small increase in Protein C activity. In conclusion, the results suggest that vitamin K1 strengthens coagulation as measured by PT decrease and increases in the activity of vitamin K-dependent clotting factors and thrombin generation. The decreased dp-ucMGP, and its potential positive short- and long-term non-coagulative effects, merits further research.

Platelet transfusion refractoriness is a serious clinical concern that complicates the management of thrombocytopenic patients. Previous studies have suggested a potential role for both complement and platelet activation based on in vitro analyses of platelet concentrates. In this study, the post-transfusion platelet response, as indicated by the corrected count increment at 1 and 24 h after prophylactic platelet transfusions, respectively, was correlated with the 1 h post-transfusion Δconcentration (1 h post-transfusion – pretransfusion) of complement and platelet activation biomarkers. The study was registered as a clinical trial at ClinicalTrials.gov (identifier: NCT02601131) and patients were recruited during inpatient care in the hematological department. Soluble terminal complement complexes, soluble P-selectin and soluble CD40 ligand were analyzed. Confirmed alloimmunized patients were excluded. Included subjects were either given platelet transfusions (n = 43) and categorized into four clinical study groups or included in a non-transfused control group (n = 10). In total, 54 transfusions were included. No transfusion-mediated complement activation was observed. The transfusions were associated with a significant increase in the concentration of soluble P-selectin (p < .001), primarily corresponding to the passive infusion of soluble P-selectin-containing plasma residuals. The Δconcentration of soluble P-selectin was, however, not significantly correlated with the corrected count increments. Thus, significant correlations between biomarkers of complement and platelet activation and the post-transfusion platelet response could not be demonstrated in this study.

Sweden does not have a national blood authority and guidelines for blood transfusions are lacking, leading to varying routines of production and usage of blood in the different regions. The minimum quality requirements are defined in EU Directive 2002/98/EG and in the Swedish SOSFS 2009:28. The standard blood components are red blood cells, plasma and platelets, while special components such as irradiated, washed, frozen-thawed or antigen-matched products are prescribed on certain clinical indications. Thresholds for transfusion of red blood cells and platelets are discussed as well as indications for plasma transfusions. Further, there is evidence that early, balanced blood transfusions in massive bleeding reduce mortality, which has led to requests for blood products in prehospital settings.

Background: Previous studies have indicated that vitamin K deficiency is common in non-bleeding critically ill patients with slightly prolonged prothrombin time-international normalized ratio (PT-INR). It has never been investigated thoroughly whether the administration of vitamin K to these patients could affect their PT-INR. Therefore, the aim of this registry study was to evaluate changes in PT-INR in response to vitamin K in critically ill patients with PT-INR in the range of 1.3–1.9. Methods: Patients admitted to a mixed 9-bed general intensive care unit at a University Hospital, between 2013 and 2019 (n = 4541) with a PT-INR between 1.3 and 1.9 at any time during the stay were identified. Patients who received vitamin K with appropriate sampling times for PT-INR and without exclusion criteria were matched with propensity score to patients from the same cohort who did not receive vitamin K (controls). PT-INR was measured at admission, within 12 h before vitamin K administration and 12–36 h following vitamin K administration. Exclusion criteria included pre-existing liver cirrhosis, any plasma or platelet transfusion, or > 1 unit red blood cell transfusion between PT-INR samplings. Results: Propensity score matching resulted in two groups of patients with 129 patients in each group. PT-INR decreased in both groups (1.4 [1.3–1.4] in the vitamin K group and 1.4 [1.3–1.6] in the controls, p < 0.001 and p = 0.004, respectively). The decrease in PT-INR was slightly more pronounced in patients who received vitamin K (delta PT-INR − 0.10 [− 0.30 to − 0.10] in the vitamin K group and − 0.10 [− 0.20 to 0.10] in the controls, p = 0.01). Conclusion: In critically ill patients with a PT-INR of 1.3–1.9, the administration of vitamin K resulted in a slightly larger decrease of PT-INR 12–36 h after administration compared to controls. Future studies should focus on identifying which patient populations may benefit most from vitamin K administration as well as whether vitamin K could be a better alternative than plasma or prothrombin complex concentrate to improve PT-INR before non-emergent invasive procedures.