Clinical guideline on reversal of direct oral anticoagulants in patients with life threatening bleeding.

BACKGROUND: Anticoagulation is essential for the treatment and prevention of thromboembolic events. Current guidelines recommend direct oral anticoagulants (DOACs) over vitamin K antagonists in DOAC-eligible patients. The major complication of anticoagulation is serious or life-threatening haemorrhage, which may necessitate prompt haemostatic intervention. Reversal of DOACs may also be required for patients in need of urgent invasive procedures. This guideline from the European Society of Anaesthesiology and Intensive Care (ESAIC) aims to provide evidence-based recommendations and suggestions on how to manage patients on DOACs undergoing urgent or emergency procedures including the treatment of DOAC-induced bleeding. DESIGN: A systematic literature search was performed, examining four drug comparators (dabigatran, rivaroxaban, apixaban, edoxaban) and clinical scenarios ranging from planned to emergency surgery with the outcomes of mortality, haematoma growth and thromboembolic complications. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to assess the methodological quality of the included studies. Consensus on the wording of the recommendations was achieved by a Delphi process. RESULTS: So far, no results from prospective randomised trials comparing two active comparators (e.g. a direct reversal agent and an unspecific haemostatic agent such as prothrombin complex concentrate: PCC) have been published yet and the majority of publications were uncontrolled and observational studies. Thus, the certainty of evidence was assessed to be either low or very low (GRADE C). Thirty-five recommendations and clinical practice statements were developed. During the Delphi process, strong consensus (>90% agreement) was achieved in 97.1% of recommendations and consensus (75 to 90% agreement) in 2.9%. DISCUSSION: DOAC-specific coagulation monitoring may help in patients at risk for elevated DOAC levels, whereas global coagulation tests are not recommended to exclude clinically relevant DOAC levels. In urgent clinical situations, haemostatic treatment using either the direct reversal or nonspecific haemostatic agents should be started without waiting for DOAC level monitoring. DOAC levels above 50 ng ml-1 may be considered clinically relevant necessitating haemostatic treatment before urgent or emergency procedures. Before cardiac surgery under activated factor Xa (FXa) inhibitors, the use of andexanet alfa is not recommended because of inhibition of unfractionated heparin, which is needed for extracorporeal circulation. In the situation of DOAC overdose without bleeding, no haemostatic intervention is suggested, instead measures to eliminate the DOACs should be taken. Due to the lack of published results from comparative prospective, randomised studies, the superiority of reversal treatment strategy vs. a nonspecific haemostatic treatment is unclear for most urgent and emergency procedures and bleeding. Due to the paucity of clinical data, no recommendations for the use of recombinant activated factor VII as a nonspecific haemostatic agent can be given. CONCLUSION: In the clinical scenarios of DOAC intake before urgent procedures and DOAC-induced bleeding, practitioners should evaluate the risk of bleeding of the procedure and the severity of the DOAC-induced bleeding before initiating treatment. Optimal reversal strategy remains to be determined in future trials for most clinical settings.

Direct oral anticoagulants in trauma patients.

PURPOSE OF REVIEW: Direct oral anticoagulants (DOACs) are increasingly prescribed for prevention of thromboembolic events. Thus, trauma care providers are facing a steadily raising number of injured patients on DOACs. RECENT FINDINGS: Despite a predictable pharmacokinetic profile, the resulting plasma levels of trauma patients upon admission and bleeding risks remain uncertain. Therefore, recent guidelines recommend the measurement of DOAC plasma concentrations in injured patients. Alternatively, DOAC specific visco-elastic tests assays can be applied to identify DOAC patients at bleeding risk.Bleeding complications in trauma patients on DOACs are generally higher compared to nonanticoagulated subjects, but comparable to vitamin K antagonists (VKAs). In particular, a traumatic brain injury does not carry an increased risk of intracranial bleeding due to a DOAK intake compared to VKAs. Current studies demonstrated that up to 14% of patients with a hip fracture are on DOACs prior to surgery. However, the majority can be operated safely within a 24h time window without an increased bleeding rate.Specific antagonists facilitate rapid reversal of patients on DOACs. Idarucizumab for dabigatran, and andexanet alfa for apixaban and rivaroxaban have been approved for life threatening bleeding. Alternatively, prothrombin complex concentrate can be used. Dialysis is a potential treatment option for dabigatran and haemoabsorption with special filters can be applied in patients on FXa-inhibitors. SUMMARY: Current guidelines recommend the measurement of DOAC plasma levels in trauma patients. Compared to VKAs, DOACs do not carry a higher bleeding risk. DOAC specific antagonists facilitate the individual bleeding management.

Clinical Course and Management of Patients with Emergency Surgery Treated with Direct Oral Anticoagulants or Vitamin K Antagonists-Results of the German Prospective RADOA-Registry.

(1) Background: The clinical management of anticoagulated patients treated with direct oral anticoagulants (DOAC) or Vitamin K antagonists (VKA) needing emergency surgery is challenging. (2) Methods: The prospective German RADOA registry investigated treatment strategies in DOAC- or VKA-treated patients needing emergency surgery within 24 h after admission. Effectiveness was analysed by clinical endpoints including major bleeding. Primary observation endpoint was in hospital mortality until 30 days after admission. (3) Results: A total of 78 patients were included (DOAC: 44; VKA: 34). Median age was 76 years. Overall, 43% of the DOAC patients and 79% of the VKA patients were treated with prothrombin complex concentrates (PCC) (p = 0.002). Out of the DOAC patients, 30% received no hemostatic treatment compared to 3% (1/34) of the VKA patients (p = 0.002), and 7% of the DOAC patients and 21% of the VKA patients developed major or clinically relevant non-major bleeding at the surgical site (p = 0.093). In-hospital mortality was 13% with no significant difference between the two treatment groups (DOAC: 11%, VKA: 15%; p > 0.20). (4) Conclusions: The 30-day in-hospital mortality rate was comparable between both patient groups. VKA patients required significantly more hemostatic agents than DOAC patients in the peri- and postoperative surgery period.

Bleeding management: rFVIIIFc in hemophilia A and liver transplantation.

BACKGROUND: In patients with severe hemophilia A prolonged bleeding may occur even in cases of minor trauma or surgery. OBJECTIVE: To investigate the feasibility and efficacy of a recombinant extended half-life (EHL) FVIII concentrate for perioperative bleeding management in a patient with severe hemophilia A undergoing liver transplantation. MATERIAL AND METHODS: Prior to transplantation FVIII activity and perioperatively required FVIII supply were estimated. In an individualized approach efmoroctocog alfa was supplemented if the intrinsic clotting time in the thrombelastometry was > 170 s. RESULTS: The patient perioperatively received a total of 28,000 IU efmoroctocog alfa. No signs of hemorrhage or complications were detected and no further intervention was necessary. CONCLUSION: The present case demonstrates that the use of an EHL FVIII is suitable for a successful perioperative bleeding control even in hemophilia patients at a high bleeding risk during major surgery. Due to the EHL constant FVIII levels could be achieved with relatively few injections. In order to confirm the obtained results, more real-world data in different operative settings are essential. Further research is needed on the use of thrombelastometry to guide substitution of factor VIII perioperatively.

3-Factor versus 4-Factor Prothrombin Complex Concentrates for the Reversal of Vitamin K Antagonist-Associated Coagulopathy: A Systematic Review and Meta-analysis.

Long-term anticoagulation is used worldwide to prevent or treat thrombotic events. Anticoagulant therapy using vitamin K antagonists (VKAs) is well established; however, anticoagulants carry an increased risk of potentially life-threatening bleeding. In cases of bleeding or need for surgery, patients require careful management, balancing the need for rapid anticoagulant reversal with risk of thromboembolic events. Prothrombin complex concentrates (PCCs) replenish clotting factors and reverse VKA-associated coagulopathy. Two forms of PCC, 3-factor (3F-PCC) and 4-factor (4F-PCC), are available. Using PRISMA methodology, we systematically reviewed whether 4F-PCC is superior to 3F-PCC for the reversal of VKA-associated coagulopathy. Of the 392 articles identified, 48 full texts were reviewed, with 11 articles identified using criteria based on the PICOS format. Data were captured from 1,155 patients: 3F-PCC, n = 651; 4F-PCC, n = 504. ROBINS-I was used to assess bias. Nine studies showed international normalized ratio (INR) normalization to a predefined goal, ranging from ≤1.5 to ≤1.3, following PCC treatment. Meta-analysis of the data showed that 4F-PCC was favorable compared with 3F-PCC overall (odds ratio [OR]: 3.50; 95% confidence interval [CI]: 1.88-6.52, p < 0.0001) and for patients with a goal INR of ≤1.5 or ≤1.3 (OR: 3.45; 95% CI: 1.42-8.39, p = 0.006; OR: 3.25; 95% CI: 1.30-8.13, p = 0.01, respectively). However, heterogeneity was substantial (I 2 = 62%, I 2 = 70%, I 2 = 64%). Neither a significant difference in mortality (OR: 0.72; 95% CI: 0.42-1.24, p = 0.23) nor in thromboembolisms was reported. These data suggest that 4F-PCC is better suited than 3F-PCC for the treatment of patients with VKA-associated coagulopathy, but further work is required for a definitive recommendation.

Role of DOAC plasma concentration on perioperative blood loss and transfusion requirements in patients with hip fractures.

BACKGROUND: There is an ever-increasing number of hip fracture (HF) patients on direct oral anticoagulants (DOAC). The impact of DOAC plasma level prior to HF surgery on perioperative blood loss and transfusion requirements has not been investigated so far. MATERIALS AND METHODS: In this retrospective study of HF patients on DOACs admitted to the AUVA Trauma Center Salzburg between February 2015 and December 2021. DOAC plasma levels were analysed prior to surgery. Patients were categorized into four DOAC groups: Group A < 30 ng/mL, Group B 30-49 ng/mL, Group C 50-79 ng/mL, and Group D ≥ 80 ng/mL. Haemoglobin concentration was measured upon admission, prior to surgery, after ICU/IMC admission, and on day 1 and 2 post-surgery. Difference in the blood loss via drains, transfusion requirements and time to surgery were compared. RESULTS: A total of 155 subjects fulfilled the predefined inclusion criteria. The median age of the predominantly female patients was 86 (80-90) years. Haemoglobin concentration in Group D was lower upon admissions but did not reach statistical significance. The decrease in haemoglobin concentration over the entire observation time was comparable between groups. Blood transfusion requirements were significantly higher in Group D compared to Group A and B (p = 0.0043). Time to surgery, intra- and postoperative blood loss via drains were not different among groups. CONCLUSION: No strong association between the DOAC plasma levels and perioperative blood loss was detected. Higher transfusion rates in patients with DOAC levels ≥ 80 ng/mL were primarily related to lower admission haemoglobin levels. DOAC concentration measurement is feasible and expedites time to surgery.

Pharmacokinetics of Phenprocoumon in Emergency Situations-Results of the Prospective Observational RADOA-Registry (Reversal Agent Use in Patients Treated with Direct Oral Anticoagulants or Vitamin K Antagonists Registry).

Background: Phenprocoumon has been used as an oral anticoagulant in patients with thromboembolic disease for more than 40 years. So far its pharmacokinetics have not been analyzed in emergency situations. Methods: Phenprocoumon-treated patients with major bleeding or urgent surgery were included in a prospective, observational registry. Phenprocoumon drug concentrations were analyzed in samples, collected as part of routine care using ultraperformance liquid chromatography tandem mass spectrometry. Moreover, anticoagulant intensity and drug half-life (t1/2) were calculated. Results: 115 patients were included. Phenprocoumon levels declined over time with a half-life of 5.27 and 5.29 days in patients with major bleedings (n = 82) and with urgent surgery (n = 33). Baseline phenprocoumon levels were 2.2 times higher in the bleeding group compared to the surgery group (1.92 vs. 0.87 ng/mL, p < 0.0001). International normalized ratio (INR) values decreased rapidly during the first 24 h. In 27.6% of patients a rebound of INR (recurrent increase > 1.5) was observed which was associated with significantly increased bleeding rates (22% vs. 4.2% in patients with or without INR rebound, p = 0.012). Conclusions: In emergency situations, the long half-life of phenprocoumon may cause INR rebound and associated recurrent bleedings. Optimal management may need to include repeated vitamin K supplementation over days.

Pharmacokinetics of Direct Oral Anticoagulants in Emergency Situations: Results of the Prospective Observational RADOA-Registry.

BACKGROUND: Direct oral anticoagulants (DOACs) are increasingly used worldwide. Little is known so far about their pharmacokinetics in emergency situations. METHODS: A prospective, observational registry was performed to determine the clinical course in consecutive patients with major bleeding or urgent surgery treated with DOACs. In samples collected as part of routine care DOAC drug concentrations were measured using ultraperformance liquid chromatography-tandem mass spectrometry. Anticoagulant intensity at first presentation and drug half-life (t 1/2), tested in repeat samples, were evaluated. RESULTS: A total of 140 patients were prospectively included. Pharmacokinetic data were available in 94% (132/140) of patients. Note that 67% (89/132) experienced life-threatening bleeding and 33% (43/132) needed an urgent surgery. For pharmacokinetic analysis a total of 605 blood samples was available. Median concentration on admission was 205 ng/mL for rivaroxaban and 108 ng/mL for apixaban. All treatment groups showed a high variation of drug concentrations at baseline. In rivaroxaban-treated patients t ½ was 17.3 hours (95% confidence interval [CI]: 15.4-19.7) without significant difference in both groups (major bleeding: t ½ 16.7 hours, 95% CI: 14.7-19.3; urgent surgery: t ½ 19.7 hours, 95% CI: 15.2-27.9; p = 0.292). In apixaban-treated patients t ½ was 25.0 hours (95% CI: 22.9-27.6) with a longer t ½ after urgent surgery (t 1/2: 30.8 hours; 95% CI: 26.9-36.4) compared with severe bleeding (t 1/2: 20.8 hours; 95% CI: 18.8-23.2; p < 0.001). CONCLUSION: Emergency patients under DOAC treatment show a high variation of anticoagulant concentrations at baseline. Compared with rivaroxaban, apixaban showed a lower median concentration on admission and a longer t ½.

Thromboelastometry fails to detect autoheparinization after major trauma and hemorrhagic shock.

BACKGROUND: Heparan sulfate is an integral component of the glycocalyx that provides an anticoagulant layer close to the endothelium. Hypoperfusion, inflammation, and sympathoadrenal activation following major trauma result in glycocalyx shedding and subsequent release of heparan sulfate into the bloodstream. The possible anticoagulant effect of this "autoheparinization" has been suggested as a potential driver of trauma-induced coagulopathy. We investigated whether thromboelastometry can be used to detect trauma-induced autoheparinization. METHODS: This study comprised three parts. First, in a retrospective clinical study of 264 major trauma patients, the clotting time (CT) in the intrinsic activation (INTEM) and intrinsic activation plus heparinase (HEPTEM) assays were evaluated upon emergency room admission. Second, in an in vivo experimental rat model of hemorrhagic-traumatic shock, the release of heparan sulfate was investigated with INTEM and HEPTEM analyses of whole blood. Third, in vitro spiking of whole blood from healthy volunteers was undertaken to assess the effects of clinically relevant quantities of heparan sulfate and heparin on CT in the INTEM and HEPTEM assays. RESULTS: In the first part, severe injury and hemorrhagic shock was not associated with any increases in INTEM CT versus HEPTEM CT. Part 2 showed that an approximate threefold increase in heparan sulfate resulting from hemorrhagic traumatic shock in rats did not prolong INTEM CT, and no significant differences between INTEM CT and HEPTEM CT were observed. Third, spiking of whole blood with heparan sulfate had no impact on INTEM CT, whereas heparin elicited significant prolongation of INTEM CT. CONCLUSION: Despite structural similarity between heparan sulfate and heparin, the amounts of heparan sulfate shed in response to trauma did not exert an anticoagulant effect that was measurable by the intrinsically activated CT in thromboelastometry. The extent to which heparan sulfate contributes to trauma-induced coagulopathy has yet to be elucidated. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

Idarucizumab in major trauma patients: a single centre real life experience.

INTRODUCTION: Trauma care providers are facing an increasing number of elderly patients on direct oral anticoagulants prior to injury. For dabigatran etexilate (DAB), the specific antagonist idarucizumab (IDA) has been approved since 2015 as a reversal agent. However, only limited data regarding the use of IDA in trauma patients are available. METHODS: We performed a retrospective analysis of trauma patients under DAB for whom IDA administration was deemed necessary to reverse DAB's antithrombotic effect. RESULTS: A total of 15 (9 male) patients were treated with IDA during the study period. The mean age was 81 ± 10 years. Intracranial haemorrhage (n = 7) and long bone fractures (n = 5) were the most common types of injury. Three patients were diagnosed as polytrauma. In all but one patient, atrial fibrillation was the indication for DAB intake. The median dose of IDA was 2.5 g (IQR 2.5-5). IDA administration decreased DAB plasma levels from 112.4 (IQR 73.4-123.4) to 5 (IQR 4-12) ng/mL (p = 0.031), thrombin time from 114.8 ± 48.3 to 16.2 ± 0.5 s (p < 0.0001) and activated partial thromboplastin time form 45.4 ± 11.3 to 34.2 ± 7.0 s (p = 0.0025). No thromboembolic events or side effects attributed to IDA were observed. All patients survived until hospital discharge. CONCLUSIONS: In trauma patients under DAB prior to injury, IDA decreased DAB plasma levels and normalized coagulation parameters. IDA appears to be safe, and no serious side effects were observed in this small cohort of patients.

Fibrinogen Supplementation and Its Indications.

Adequate plasma levels of fibrinogen are essential for clot formation, and in severe bleeding, fibrinogen reaches a critically low plasma concentration earlier than other coagulation factors. Although the critical minimum concentration of fibrinogen to maintain hemostasis is a matter of debate, many patients with coagulopathic bleeding require fibrinogen supplementation. Among the treatment options for fibrinogen supplementation, fibrinogen concentrate may be viewed by some as preferable to fresh frozen plasma or cryoprecipitate. The authors review major studies that have assessed fibrinogen treatment in trauma, cardiac surgery, end-stage liver disease, postpartum hemorrhage, and pediatric patients. Some but not all randomized controlled trials have shown that fibrinogen concentrate can be beneficial in these settings. The use of fibrinogen as part of coagulation factor concentrate based therapy guided by point-of-care viscoelastic coagulation monitoring (ROTEM [rotational thromboelastometry] or TEG [thromboelastography]) appears promising. In addition to reducing patients' exposure to allogeneic blood products, this strategy may reduce the risk of complications such as transfusion-associated circulatory overload, transfusion-related acute lung injury, and thromboembolic adverse events. Randomized controlled trials are challenging to perform in patients with critical bleeding, and more evidence is needed in this setting. However, current scientific rationale and clinical data support fibrinogen repletion in patients with ongoing bleeding and confirmed fibrinogen deficiency.

Impact of Direct Oral Anticoagulants in Patients With Hip Fractures.

OBJECTIVE: To assess the impact of direct oral anticoagulant (DOAC) intake compared with Coumadin (COU) in patients suffering hip fractures (HFs). DESIGN: Retrospective cohort analysis. SETTING: Level 1 Trauma Center. INTERVENTION: Timing of surgical hip fixation. PATIENTS: Three-hundred twenty patients 65 years of age or older with isolated HF were enrolled into the study: 207 (64.7%) without any antithrombotic therapy (no-ATT), 59 (18.4%) on COU, and 54 (16.9%) on DOACs. MAIN OUTCOME MEASUREMENTS: Time to surgery, blood loss, mortality, hospital length of stay, red blood cell transfusion, use of reversal agents, and Charlson Comorbidity Index. RESULTS: Patients on COU and DOACs had a higher Charlson Comorbidity Index compared with the no-ATT group (P < 0.0001). Despite the fact that significantly more patients received reversal agents in the COU group compared with DOAC medication (P < 0.0001), percentage of transfused patients were similar (54.2% vs. 53.7%). Time to surgery was significantly shorter in the no-ATT group when compared with DOAC patients (12-29.5 hours, respectively). No difference in postoperative hemorrhage, intensive care unit length of stay, and mortality was observed between groups. CONCLUSIONS: DOAC medication in HF patients caused long elapse time until surgical repair. We found no evidence of higher bleeding rates in HF patients on DOACs compared with COUs. Earlier HF fixation might be indicated in DOAC patients. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

In vitro comparison of the hemocompatibility of two centrifugal left ventricular assist devices.

OBJECTIVES: Shear stress from left ventricular assist devices induces von Willebrand factor degradation and platelet dysfunction, leading to nonsurgical bleeding. We characterized the hemostatic changes induced by 2 centrifugal left ventricular assist devices, the HeartMate 3 (Abbott Inc, Chicago, Ill) and the EVAHEART (Evaheart Inc, Houston, Tex), for comparison. METHODS: Whole blood from 8 healthy volunteers was used ex vivo. Blood from the same donor was used for 6 hours of circulation in a miniature mock-loop system consisting of 2 identical extracorporeal circuits to compare the following experimental settings: (1) optimal revolutions per minute (rpm) for the HeartMate 3 (n = 4; 5000 rpm) and the EVAHEART (n = 4; 2500 rpm) and (2) equal rpm (3000 rpm for the HeartMate 3 and EVAHEART, n = 4 vs n = 4). For both settings, blood flow was adjusted to 1 mock-loop filling volume per minute (HeartMate 3 = 82 mL/min, EVAHEART = 100 mL/min). A panel of coagulation markers was analyzed to investigate hemostatic changes. RESULTS: The free plasma hemoglobin concentration was significantly lower in the EVAHEART compared with the HeartMate 3 after 6 hours of mock-loop circulation under both settings (optimal: 37 ± 31 vs 503 ± 173 mg/dL, P < .0001; equal: 27 ± 4 vs 139 ± 135 mg/dL, P = .024). Loss of von Willebrand factor high-molecular-weight multimers occurred in both left ventricular assist devices and settings, but the von Willebrand factor:activity/von Willebrand factor:antigen ratio after 6 hours was significantly lower in optimal settings for the HeartMate 3 (P = .009). The thrombin-antithrombin complex level was significantly lower with the EVAHEART for both settings (P < .0001). CONCLUSIONS: The EVAHEART left ventricular assist device caused less hemolysis, resulted in lower coagulation activation, and provided better preservation of von Willebrand factor functional activity compared with the HeartMate 3 device. These findings prove that left ventricular assist device design plays a major role in minimizing blood damage during left ventricular assist device support.

The relevance of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D concentration for postoperative infections and postoperative organ dysfunctions in cardiac surgery patients: The eVIDenCe study.

BACKGROUND & AIMS: Recent studies indicate that vitamin D deficiency is associated with increased morbidity and mortality in critically ill patients. Knowledge about the functional role and clinical relevance of vitamin D for patients undergoing cardiac surgery is sparse. Therefore, we investigated the clinical significance of vitamin D levels on outcome of cardiac surgery patients. METHODS: 92 patients undergoing elective cardiac surgery with cardiopulmonary arrest were included in this prospective observational pilot study. 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were measured prior to surgery, immediately postoperatively as well as 6, 12 and 24 h after surgery. We assessed postoperative organ dysfunctions, infections and death until hospital discharge. RESULTS: The serum concentration of 1,25(OH)2D significantly decreased intraoperatively by 29.3% (p < 0.001) and was significantly lower at any postoperative time point compared to baseline values, whereas 25OHD levels did not show significant changes during the observation period. Coronary artery bypass graft (CABG) patients had significant higher baseline 1,25(OH)2D values than patients with valve surgery (39.7 ± 13.9 ng/l vs. 30.1 ± 14.1 ng/l, p = 0.010) or CABG + valve surgery (39.7 ± 13.9 ng/l vs. 32.6 ± 11.8 ng/l, p = 0.044). Our data showed a significant odds ratio to develop postoperative organ dysfunction (OR 0.95; p = 0.009) and PCT levels ≥5 µg/l (OR 0.94; p = 0.046) for every ng/l increment in 1,25(OH)2D, when performing multivariable analysis and after adjusting for preoperative illness and demographics. In addition, multivariable-adjusted statistical analyses revealed that patients stayed significantly shorter on ICU (-0.21 h; p = 0.001) and in hospital (-2.6 days; p = 0.009) for every ng/l increment in 1,25(OH)2D. CONCLUSION: Our data highlight important evidence about the clinical significance of 1,25(OH)2D levels in cardiac surgery patients. Higher levels were associated with significantly less postoperative organ dysfunctions, elevated PCT levels, death and prolonged hospital stay. 1,25(OH)2D levels decreased significantly intra- and postoperatively, while serum levels of 25OHD did not. TRIAL REGISTRATION: clinicaltrials.gov (NCT02488876), registered May 1, 2015.

The Reversal of Direct Oral Anticoagulants in Animal Models.

Several direct oral anticoagulants (DOACs), including direct thrombin and factor Xa inhibitors, have been approved as alternatives to vitamin K antagonist anticoagulants. As with any anticoagulant, DOAC use carries a risk of bleeding. In patients with major bleeding or needing urgent surgery, reversal of DOAC anticoagulation may be required, presenting a clinical challenge. The optimal strategy for DOAC reversal is being refined, and may include use of hemostatic agents such as prothrombin complex concentrates (PCCs; a source of concentrated clotting factors), or DOAC-specific antidotes (which bind their target DOAC to abrogate its activity). Though promising, most specific antidotes are still in development.Preclinical animal research is the key to establishing the efficacy and safety of potential reversal agents. Here, we summarize published preclinical animal studies on reversal of DOAC anticoagulation. These studies (n = 26) were identified via a PubMed search, and used rodent, rabbit, pig, and non-human primate models. The larger of these animals have the advantages of similar blood volume/hemodynamics to humans, and can be used to model polytrauma. We find that in addition to varied species being used, there is variability in the models and assays used between studies; we suggest that blood loss (bleeding volume) is the most clinically relevant measure of DOAC anticoagulation-related bleeding and its reversal.The studies covered indicate that both PCCs and specific reversal agents have the potential to be used as part of a clinical strategy for DOAC reversal. For the future, we advocate the development and use of standardized, clinically, and pharmacologically relevant animal models to study novel DOAC reversal strategies.

Dose requirements for idarucizumab reversal of dabigatran in a lethal porcine trauma model with continuous bleeding.

Idarucizumab is licensed for emergency reversal of dabigatran. A single 5 g dose is usually sufficient, but higher doses may sometimes be required and optimum dosing has not been defined. It was the aim of this study to investigate the effect of idarucizumab, given once or as a split dose, after double trauma in pigs anticoagulated with dabigatran. Dabigatran etexilate (30 mg/kg bid) was given to 18 male pigs orally for 3 days. On day 4, animals were randomised 1:1:1 to receive idarucizumab 60+0, 60+60 or 120+0 mg/kg. Doses were administered 15 and 75 minutes after initial liver trauma. At 60 minutes, a second liver injury was undertaken. Animals were monitored for 5 hours after initial trauma or until death. Blood loss during the first hour was 990 ± 109 ml, 988 ± 84 ml and 964 ± 75 ml in the 60+0, 60+60 and 120+0 groups, respectively. In the 120+0 and 60+60 groups, total blood loss was 1659 ± 346 and 1426 ± 106 ml, respectively, and survival at 5 hours was 100 %. However, in the 60+0 group, total blood loss was 3561 ± 770 ml and survival was 50 %. Analysis of dabigatran plasma concentrations showed that equimolar concentrations of idarucizumab are necessary to bind all dabigatran and achieve sufficient thrombin generation. At sufficient doses, idarucizumab rapidly reduced blood loss and improved survival in this lethal porcine model of double trauma with dabigatran anticoagulation. In clinical practice, should bleeding continue after initial treatment with the approved 5 g dose of idarucizumab, a second dose may potentially be effective to control bleeding caused by redistribution of unbound dabigatran.

Coagulation Management in Jersey Calves: An ex vivo Study.

OBJECTIVE: Jersey calves are frequently used as an experimental animal model for in vivo testing of cardiac assist devices or orthopedic implants. In this ex vivo study, we analyzed the coagulation system of the Jersey calves and the potential of human-based coagulation management to circumvent perioperative bleeding complications during surgery. Experimental Procedure: Blood from 7 Jersey calves was subjected to standard laboratory tests and thromboelastometry analysis. An ex vivo model of dilutional coagulopathy was used to study the effects of fibrinogen or prothrombin complex concentrate supplementation. Fibrinolysis was induced with tissue plasminogen activator to identify potential therapeutic strategies involving tranexamic acid or aprotinin. Furthermore, anticoagulation strategies were evaluated by incubating the blood samples with dabigatran or rivaroxaban. RESULTS: Baseline values for thromboelastometry and standard laboratory parameters, including prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, and D-dimers, were established. Fifty percent diluted blood showed a statistically significant impairment of hemostasis. The parameters significantly improved after the administration of fibrinogen or prothrombin complex concentrate. Tranexamic acid and aprotinin ameliorated tissue plasminogen activator-induced fibrinolysis. Both dabigatran and rivaroxaban significantly prolonged the coagulation parameters. CONCLUSIONS: In this ex vivo study, coagulation factors, factor concentrate, antifibrinolytic reagents, and anticoagulants regularly used in the clinic positively impacted coagulation parameters in Jersey calf blood.