Influence of selected antithrombotic treatment on thromboelastometric results

Is ROTEM Diagnostic in Trauma Care Associated with Lower Mortality Rates in Bleeding Patients?—A Retrospective Analysis of 7461 Patients Derived from the TraumaRegister DGU®

Introduction: Death from uncontrolled trauma haemorrhage and subsequent trauma-induced coagulopathy (TIC) is potentially preventable. Point-of-care devices such as rotational thromboelastometry (ROTEM^®) are advocated to detect haemostatic derangements more rapidly than conventional laboratory diagnostics. Regarding reductions in RBC transfusion, the use of ROTEM has been described as being efficient and associated with positive outcomes in several studies. Objective: The effect of ROTEM use was assessed on three different outcome variables: (i) administration of haemostatics, (ii) rate of RBC transfusions and (iii) mortality in severely injured patients. Methods and Material: A retrospective analysis of a large data set of severely injured patients collected into the TraumaRegister DGU^® between 2009 and 2016 was conducted. The data of 7461 patients corresponded to the inclusion criteria and were subdivided into ROTEM-using and ROTEM-non-using groups. Both groups were analysed regarding (i) administration of haemostatics, (ii) rate of RBC transfusions and (iii) mortality. Results: A lower mortality rate in ROTEM-using groups was observed (p = 0.043). Furthermore, more patients received haemostatic medication when ROTEM was used. In ROTEM-using groups, there was a statistically relevant higher application of massive transfusion. Conclusions: In this retrospective study, the use of ROTEM was associated with reduced mortality and an increased application of haemostatics and RBC transfusions. Prospective evidence is needed for further evidence-based recommendations.

Viscoelastic Testing in the Clinical Management of Subarachnoid Hemorrhage and Intracerebral Hemorrhage

Subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH) are both debilitating and life-threatening incidents calling for immediate action and treatment. This review focuses on the applicability of viscoelastic testing (rotational thromboelastometry or thromboelastography [TEG]) in the management of SAH and ICH. A systematic literature search was performed in PubMed and EMBASE. Studies including patients with SAH or ICH, in which viscoelastic testing was performed, were identified. In total, 24 studies were included for analysis, and further subdivided into studies on SAH patients investigated prior to stenting or coiling (n = 12), ICH patients (n = 8) and studies testing patients undergoing stenting or coiling, or ischemic stroke patients undergoing thrombolysis or thrombectomy and developing ICH as a complication (n = 5). SAH patients had increased clot firmness, and this was associated with a higher degree of early brain injury and higher Hunt-Hess score. SAH patients with delayed cerebral ischemia had higher clot firmness than patients not developing delayed cerebral ischemia. ICH patients showed accelerated clot formation and increased clot firmness in comparison to healthy controls. Patients with hematoma expansion had longer clot initiation and lower platelet aggregation than patients with no hematoma expansion. During stent procedures for SAH, adjustment of antiplatelet therapy according to TEG platelet mapping did not change prevalence of major bleeding, thromboembolic events, or functional outcome. Viscoelastic testing prior to thrombolysis showed conflicting results in predicting ICH as complication. In conclusion, viscoelastic testing suggests hypercoagulation following SAH and ICH. Further investigation of the predictive value of increased clot firmness in SAH seems relevant. In ICH, the prediction of hematoma expansion and ICH as a complication to thrombolysis might be clinically relevant.

Rotational Thromboelastometry in High-Risk Patients on Dual Antithrombotic Therapy After Percutaneous Coronary Intervention

Aims: Patients using antithrombotic drugs after percutaneous coronary intervention (PCI) are at risk for bleeding and recurrent ischemia. We aimed to explore routine and tissue plasminogen activated (tPA) ROTEM results in a post-PCI population on dual antithrombotic treatment.

Methods and Results: In this prospective cohort, 440 patients treated with double antithrombotic therapy after recent PCI and with ≥3 risk factors for either ischemic or bleeding complications were included and compared with a control group (n = 95) consisting of perioperative patients not using antithrombotic medication. Laboratory assessment, including (tPA) ROTEM, was performed one month post-PCI and bleeding/ischemic complications were collected over a five-month follow-up. Patients were stratified by antithrombotic regimen consisting of a P2Y12 inhibitor with either aspirin (dual antiplatelet therapy; DAPT, n = 323), a vitamin K antagonist (VKA, n = 69) or a direct oral anticoagulant (DOAC, n = 48). All post-PCI patients had elevated ROTEM clot stiffness values, but only the DAPT group additionally presented with a decreased fibrinolytic potential as measured with tPA ROTEM. Patients receiving anticoagulants had prolonged clotting times (CT) when compared to the control and DAPT group; EXTEM and FIBTEM CT could best discriminate between patients (not) using anticoagulants (AUC > 0.97). Furthermore, EXTEM CT was significantly prolonged in DAPT patients with bleeding complications during follow-up (68 [62–70] vs. 62 [57–68], p = 0.030).

Conclusion: ROTEM CT has high potential for identifying anticoagulants and tPA ROTEM could detect a diminished fibrinolytic potential in patients using DAPT. Furthermore, the ability of EXTEM CT to identify patients at risk for bleeding may be promising and warrants further research.

Platelet function assessed by ROTEM® platelet in patients receiving antiplatelet therapy during cardiac and vascular surgery

Patients undergoing coronary artery bypass graft (CABG) surgery or carotid endarterectomy (CEA) continue antiplatelet therapy perioperatively, which may increase bleeding risk. We aimed to investigate whether Rotational thromboelastometry (ROTEM^®) platelet, a newly marketed platelet function analysis, would detect antiplatelet therapy in CABG and CEA patients; whether detection of reduced platelet function was associated with increased bleeding; and whether ex vivo desmopressin increased platelet function. We included 20 CABG patients continuing aspirin and 20 CEA patients continuing clopidogrel (n = 1) or clopidogrel and aspirin (n = 19). Platelet function was analyzed with ROTEM^® platelet and light transmission aggregometry (LTA). According to the lower reference limit, ROTEM^® platelet managed to detect aspirin, but clopidogrel detection was inadequate compared to LTA. Using a previously published cut-off for bleeding risk, 6 (30%) patients receiving aspirin and 4 (21%) patients receiving both clopidogrel and aspirin demonstrated platelet function below this cut-off. One of the four CEA patients below the cut-off died from intracerebral hemorrhage postoperatively. CABG patients below (n = 6) and above (n = 14) the cut-off did not differ in chest tube output (median [range]: 373 ml [250-900] vs. 368 ml [195-820]). Ex vivo addition of desmopressin did not increase platelet function. In conclusion, ROTEM^® platelet does reveal aspirin treatment whereas clopidogrel treatment is most often overlooked. Due to low bleeding in the study population, it was not possible to conclude on the association with bleeding risk.

Whole blood platelet aggregation determined by the ROTEM platelet equipment; reference intervals and stability

Point of care testing of residual effect of antiplatelet therapy in trauma patients or during major surgery may result in improved clinical management of significant bleeding. We included 121 healthy individuals (57 females and 64 males, aged 22-65 years) in order to establish reference intervals for platelet aggregation induced by adenosine diphosphate (ADPTEM, 10 µM), arachidonic acid (ARATEM, 0.42 mM) and thrombin activating peptide (TRAPTEM, 36 µM) employing the ROTEM platelet module. Further, the impact of citrate (3.2%) and hirudin (>15 µg/ml) as anticoagulants was evaluated. Finally, we investigated assay stability (15, 30, 60, and 120 min after blood sampling) (n = 8) and between-day variation (n = 5). We report reference intervals for 121 healthy individuals and reference intervals by gender. We observed significantly higher platelet aggregation in females than in males (all P-values < 0.05). No correlation between age and platelet aggregation was observed, except for the parameter TRAPTEM amplitude (A6), in which a decline in A6 was observed with increasing age (P = 0.03). We observed significantly lower levels of platelet aggregation in citrate tubes than in hirudin tubes (all P-values < 0.05), except from TRAPTEM maximum slope, where no significant difference was observed (P = 0.40).The stability was acceptable (≤20% deviation) for up to 120 min for ARATEM in citrate tubes, and up to 60 min for the ADPTEM and TRAPTEM assays in citrate tubes. In hirudin tubes we found ADPTEM and ARATEM assays to be stable for 60 min, while the stability of TRAPTEM in hirudin tubes was found to be stable for 30 min. Using citrate tubes, the between-day variation (mean coefficient of variation, CV) was 19-20% for ADPTEM, 19-26% for TRAPTEM, and 10% for ARATEM, whereas the mean CV was 11-13% for all three assays in hirudin tubes.In conclusion, we established combined and gender-specific reference intervals for three platelet aggregation assays in both citrate- and hirudin tubes. In citrate tubes, the stability of the ROTEM platelet assays was 60-120 min, while the stability in hirudin tubes was 30-60 min. The between-day variation was lowest for samples obtained in hirudin tubes.