Shifts of Transfusion Demand in Cardiac Surgery After Implementation of Rotational Thromboelastometry–Guided Transfusion Protocols: Analysis of the HEROES-CS (HEmostasis Registry of patiEntS in Cardiac Surgery) Observational, Prospective Open Cohort Database

Comparison of two viscoelastic testing devices in a porcine model of surgery, hemorrhage and resuscitation

Introduction

Viscoelastic hemostatic assays (VHA) are integral in contemporary hemostatic resuscitation, offering insights into clot formation, firmness, and lysis for rapid diagnosis and targeted therapy. Large animal models, particularly swine, provide anatomical and physiological analogies for coagulation research. Despite the growing use of VHAs, the ClotPro® device's applicability in porcine models remains unexplored. This study investigates ClotPro® in a porcine model of abdominal surgery, severe hemorrhage, and resuscitation, comparing it with the established ROTEM® delta system.

Methods

Twenty-seven healthy pigs underwent abdominal surgery, hemorrhage and resuscitation. ClotPro® and ROTEM® were used to assess viscoelastic hemostatic properties at baseline, after surgery, 60 min after shock induction, 60 and 120 min after resuscitation.

Results

Clotting times in extrinsically and intrinsically stimulated assays exhibited fair to moderate correlation. Clot firmness in extrinsically stimulated tests could be used interchangeably while fibrin polymerization assays revealed significant differences between the devices. Fibrin polymerization assays in ClotPro® consistently yielded higher values than ROTEM®. Furthermore, the study evaluated the ClotPro® TPA-test's applicability in porcine blood, revealing failure of lysis induction in porcine blood samples.

Conclusion

This research contributes valuable insights into the use of ClotPro® in porcine models of hemorrhage and coagulopathy, highlighting both its applicability and limitations in comparison to ROTEM® delta. The observed differences, especially in fibrin polymerization assays, emphasize the importance of understanding device-specific characteristics when interpreting results. Due to its inapplicability, TPA-test should not be used in porcine blood to evaluate fibrinolytic potential. The study provides a foundation for future investigations into the use of different viscoelastic hemostatic assays in porcine animal models.

The Diagnostic Accuracy of EXTEM and HEPTEM Clotting Times Versus Standard Laboratory Tests in Cardiac Surgical Patients With and Without Normal FIBTEM Values

OBJECTIVES

There is extensive evidence to support the use of FIBTEM to identify hypofibrinogenemia during cardiac surgery, but less to support the use of EXTEM and INTEM clotting times (CTs) to identify other plasmatic coagulation factor deficiencies. The aim of the current study was to assess the diagnostic accuracy of EXTEM, INTEM, and HEPTEM CTs, using laboratory international normalized ratio (INR) and activated partial thromboplastin time (aPTT) as reference standards.

DESIGN

This was a retrospective diagnostic accuracy study.

SETTING

The work took place at a tertiary referral hospital.

PARTICIPANTS

A total of 176 cardiac surgical patients were enrolled.

INTERVENTIONS

INR, aPTT, ROTEM EXTEM, INTEM, and HEPTEM were measured post-heparin reversal after cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

Sensitivity, specificity, and positive (PPVs) and negative predictive values (NPVs) for EXTEM CT >80 seconds and HEPTEM CT >280 seconds to detect INR ≥2.0, and INTEM CT >205 seconds to detect aPTT ≥38.5 seconds were calculated for all patients and the subset with normal FIBTEM A5 (>6 mm). The prevalence of INR ≥2.0 was 13%. EXTEM CT >80 seconds had a sensitivity of 1.00, specificity of 0.25, PPV of 0.17, and NPV of 1.00. HEPTEM CT >280 seconds had a sensitivity of 0.91, specificity of 0.38, PPV of 0.18, and NPV of 0.97. INTEM CT >205 seconds had a sensitivity of 0.97, specificity of 0.11, PPV of 0.57, and NPV of 0.75 for aPTT ≥38.5 seconds. These values were similar for the subset of patients with normal FIBTEM A5.

CONCLUSIONS

EXTEM CT >80 seconds and HEPTEM CT >280 seconds have high sensitivities and NPVs for INR >2.0, which would effectively "rule out" INR >2.0 as a cause for excessive bleeding. However, the low specificities and PPVs indicate they would be less effective in ruling it in. INTEM CT >205 seconds had low PPV and NPV in identifying aPTT >38.5 seconds.

The Role of Viscoelastic Testing in Assessing Hemostasis: A Challenge to Standard Laboratory Assays?

Viscoelastic testing is increasingly being used in clinical and research settings to assess hemostasis. Indeed, there are potential situations in which viscoelastic testing is reportedly superior to standard routine laboratory testing for hemostasis. We report the current testing platforms and terminology, as well as providing a concise narrative review of the published evidence to guide its use in various clinical settings. Notably, there is increasing evidence of the potential utility of viscoelastic testing for assessment of direct oral anticoagulants, and bleeding associated with chronic liver disease, orthotopic liver transplantation, cardiac surgery, trauma, obstetrics and pediatrics.

Viscoelastic Testing Methods

Viscoelastic testing methods examine the real-time formation of a clot in a whole blood sample, and include thromboelastography (TEG), rotational thromboelastometry (ROTEM), and several other testing platforms. They allow for concurrent assessment of multiple aspects of clotting, including plasmatic coagulation factors, platelets, fibrinogen, and the fibrinolytic pathway. This testing is rapid and may be performed at the point-of-care, allowing for prompt identification of coagulopathies to guide focused and rational administration of blood products as well as the identification of anticoagulant effect. With recent industry progression towards user-friendly, cartridge-based, portable instruments, viscoelastic testing has emerged in the 21st century as a powerful tool to guide blood transfusions in the bleeding patient, and to identify and treat both bleeding and thrombotic conditions in many operative settings, including trauma surgery, liver transplant surgery, cardiac surgery, and obstetrics. In these settings, the use of transfusion algorithms guided by viscoelastic testing data has resulted in widespread improvements in patient blood management as well as modest improvements in select patient outcomes. To address the increasingly wide adoption of viscoelastic methods and the growing number of medical and laboratory personnel tasked with implementing, performing, and interpreting these methods, this chapter provides an overview of the history, physiology, and technology behind viscoelastic testing, as well as a practical review of its clinical utility and current evidence supporting its use. Also included is a review of testing limitations and the contextual role played by viscoelastic methods among all coagulation laboratory testing.

Viscoelastic testing: Critical appraisal of new methodologies and current literature

United States Food and Drug Administration (FDA)-approved viscoelastic testing (VET) methodologies have significantly changed in the last 10 years, with the availability of cartridge-based VET. Some of these cartridge-based methodologies use harmonic resonance-based clot detection. While VET has always allowed for the evaluation of real-time clot formation, cartridge-based VET provides increased ease of use as well as greater portability and robustness of results in out-of-laboratory environments. Here we review the use of VET in a variety of clinical contexts, including cardiac surgery, trauma, liver transplant, obstetrics, and hypercoagulable states such as COVID-19. As of now, high quality randomized trial evidence for new generation VET (TEG 6s, HemoSonics Quantra, ROTEM sigma) is limited. Nevertheless, the use of VET-guided transfusion algorithms appears to result in reduced blood usage without worsening of patient outcomes. Future work comparing the new generation VET instruments and continuing to validate clinically important cut-offs will help move the field of point-of-care coagulation monitoring forward and increase the quality of transfusion management in bleeding patients.

Improving Patient Blood Management Programs: An Implementation Science Approach

Organized patient blood management (PBM) programs function in numerous hospitals and health systems around the world contributing to improved patient outcomes as well as increased patient engagement, decreased resource use, and reductions in health care costs. PBM "programming" ranges from the implementation of single strategies/initiatives to comprehensive programs led by dedicated clinicians and PBM committees, employing the use of multiple PBM strategies. Frontline health care professionals play an important role in leading, implementing, operationalizing, measuring, and sustaining successful PBM programs. In this article, we provide practical implementation guidance to support key clinical, administrative, leadership, and structural elements required for the safe and comprehensive delivery of care in PBM programs at the local level.

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.

The Choice between Plasma-Based Common Coagulation Tests and Cell-Based Viscoelastic Tests in Monitoring Hemostatic Competence: Not an either-or Proposition

There has been a significant interest in the last decade in the use of viscoelastic tests (VETs) to determine the hemostatic competence of bleeding patients. Previously, common coagulation tests (CCTs) such as the prothrombin time (PT) and partial thromboplastin time (PTT) were used to assist in the guidance of blood component and hemostatic adjunctive therapy for these patients. However, the experience of decades of VET use in liver failure with transplantation, cardiac surgery, and trauma has now spread to obstetrical hemorrhage and congenital and acquired coagulopathies. Since CCTs measure only 5 to 10% of the lifespan of a clot, these assays have been found to be of limited use for acute surgical and medical conditions, whereby rapid results are required. However, there are medical indications for the PT/PTT that cannot be supplanted by VETs. Therefore, the choice of whether to use a CCT or a VET to guide blood component therapy or hemostatic adjunctive therapy may often require consideration of both methodologies. In this review, we provide examples of the relative indications for CCTs and VETs in monitoring hemostatic competence of bleeding patients.

Plasma transfusion practices: A multicentre electronic audit

BACKGROUND AND OBJECTIVES

Plasma is often transfused to patients with bleeding or requiring invasive procedures and with abnormal tests of coagulation. Chart audits find half of plasma transfusions unnecessary, resulting in avoidable complications and costs. This multicentre electronic audit was conducted to determine the proportion of plasma transfused without an indication and/or at a sub-therapeutic dose.

METHODS

Data were extracted on adult inpatients in 2017 at five academic sites from the hospital electronic chart, laboratory information systems and the Canadian Institute for Health Information Discharge Abstract Database. Electronic criteria for plasma transfusion outside recommended indications were: (1) international normalized ratio (INR) < 1.5 with no to moderate bleeding; (2) INR ≥ 1.5, with no to mild bleeding and no planned procedures; and (3) no INR before or after plasma infusion. Sub-therapeutic dose was defined as ≤2 units transfused.

RESULTS

In 1 year, 2590 patients received 6088 plasma transfusions encompassing 11,490 units of plasma occurred at the five sites. 77.7% of events were either outside indications or under-dosed. Of these, 34.8% of plasma orders had no indication identified, and 62% of these occurred in non-bleeding patients and no planned procedure with an isolated elevated INR. 70.7% of transfusions were under-dosed. Most plasma transfusions occurred in the intensive care unit or the operating room. Inter-hospital variability in peri-transfusion testing and dosing was observed.

CONCLUSION

The majority of plasma transfusions are sub-optimal. Local hospital culture may be an important driver. Electronic audits, with definitions employed in this study, may be a practical alternative to costly chart audits.

Rotational Thromboelastometry Values After On-Pump Cardiac Surgery - A Retrospective Cohort Study

BACKGROUND

Viscoelastic coagulation monitoring is recommended for coagulation management after cardiac surgery, but optimum target values are poorly defined.

AIMS

To determine "to-be-expected" values in rotational thromboelastometry (ROTEM) after heparin reversal, to correlate ROTEM parameters with fibrinogen levels and platelet count, and to estimate the effect of hemoglobin levels on these measurements.

METHODS

We retrospectively analyzed 571 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass from 12/2018 to 08/2020. ROTEM and conventional laboratory measurements were performed 5 to 10 minutes after protamine administration.

RESULTS

Clotting times in EXTEM, INTEM, and FIBTEM were significantly prolonged (72.6%, 96.1%, and 31.8% above reference ranges, respectively). Clot firmness parameters in EXTEM and INTEM were relevantly reduced (7.9% to 14.4% and 9.1% to 32.3% below the reference ranges, respectively). There was an excellent linear correlation of FIBTEM amplitude after 10 min (A10) and of maximal clot firmness (MCF) with fibrinogen concentrations (r = .81 and .80). Areas under receiver operating characteristic (AUROC) for identifying hypofibrinogenemia <1.5 g/L were between .80 and .87. No effect of hematocrit was observed. We also found a linear correlation of EXTEM, INTEM, and EXTEM-FIBTEM at both A10 and MCF with platelet counts (.32 to .68). The AUROCs for identifying thrombocytopenia (<100,000/μL) were .79 to .84, and were greater for A10 than for MCF measurements (P=.074, .001, and <.001, respectively).

CONCLUSIONS

"To-be-expected" ROTEM values after CPB are different from the published reference ranges. ROTEM parameters might allow for reliable estimation of fibrinogen level and platelet count without being influenced by hematocrit.

Anaesthetic-surgical guide in the treatment of ascending aorta and surgery of the ascending aorta and aortic arch. Consensus document of the Spanish Society of Cardiovascular and Endovascular Surgery and the Sociedad of Anaesthesiology, Resuscitation and Pain Therapy

Aortic pathology is always a challenge for the clinician, and must be diagnosed and treated by a multidisciplinary team due to the technical and technological complexity of the resources used. Ongoing efforts to implement a systematic, protocolized approach involving "Aortic teams" made up of cardiologists, cardiac surgeons, vascular surgeons, anaesthesiologists and radiologists, among others are now leading to improved outcomes. The aim of this consensus document drawn up by the Aortic working groups of the Spanish Society of Anaesthesiology, Resuscitation and Pain Therapy (SEDAR) and the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) is to disseminate a set of working protocols. The latest consensus document of the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society for Vascular Surgery (ESVS) define the concept of "AORTIC TEAM"(1). The aortic team should be closely involved from diagnosis to treatment and finally follow-up, and should be formed of cardiac and vascular surgeons working together with anaesthesiologists, cardiologists, radiologists and geneticists. Treatment of aortic pathologies should be centralised in large centres, because this is the only way to effectively understand the natural course of the disease, provide the entire range of treatment options under one umbrella and treat potential complications. A streamlined emergent care pathway (24/7 availability), adequate transportation and transfer capabilities, as well as rapid activation of the multidisciplinary team must be available. In light of the complexity and constant evolution of therapeutic options, we present this first version of the Anaesthesiology and surgical guidelines for surgery of the ascending aorta and aortic arch. Some questions will no doubt remain unanswered, and future versions will include new techniques that, though implemented in some centres, are still not widely recommended.

Clinical application of viscoelastic point-of-care tests of coagulation-shifting paradigms

Bleeding during cardiac surgery, liver transplant, trauma and post partum hemorrhage are often multifactorial and these factors are dynamic as new factors crop up during the course of management. Conventional tests of coagulation offer information of a part of the coagulation system and also is time consuming. Viscoelastic point of care tests (VE POCTs) like rotational thromboelastometry, thromboelastogram and Sonoclot, are based on analysis of the viscoelastic properties of clotting blood and provide information for the entire coagulation pathway. In this comprehensive review being presented here, we have examined the pros and cons of VE POCTs including clinical, cost and survival benefits. The recommendations of the various guidelines regarding use of VE POCTs in various scenarios have been discussed. The review also tried to offer suggestions as to their optimal role in management of bleeding during cardiac surgeries, extracorporeal membrane oxygenation, left ventricular assist devices, liver transplant and briefly in trauma and postpartum hemorrhage.

Fibrinogen and Bleeding in Adult Cardiac Surgery: A Review of the Literature

Background: Fibrinogen is a substrate for blood clots formation. In cardiac surgery, a number of different mechanisms lead to a decrease in fibrinogen levels and consequent impaired haemostasis. Patients undergoing cardiac surgery are therefore frequently exposed to blood loss and allogeneic blood transfusion, which are risk factors associated with morbidity and mortality. Thus, particular efforts in fibrinogen management should be made to decrease bleeding and the need for blood transfusion. Therefore, fibrinogen remains an active focus of investigations from basic science to clinical practice. This review aims to summarise the latest evidence regarding the role of fibrinogen and current practices in fibrinogen management in adult cardiac surgery. Methods: The PubMed database was systematically searched for literature investigating the role and disorders of fibrinogen in cardiac surgery and diagnostic and therapeutic procedures related to fibrinogen deficiency aimed at reducing blood loss and transfusion requirements. Clinical trials and reviews from the last 10 years were included. Results: In total, 146 articles were analysed. Conclusion: The early diagnosis and treatment of fibrinogen deficiency is crucial in maintaining haemostasis in bleeding patients. Further studies are needed to better understand the association between fibrinogen levels, bleeding, and fibrinogen supplementation and their impacts on patient outcomes in different clinical settings.

The effect of a viscoelastic-guided bleeding algorithm implementation on blood products use in adult liver transplant patients. A propensity score-matched before-after study

BACKGROUND

Perioperative blood products transfusion is correlated with increased morbidity and mortality in liver transplantation (LTx). The objectives of our study are to assess the effect of a standardized viscoelastic test (VET)-guided bleeding management algorithm implementation on intraoperative bleeding, allogenic blood products and factor concentrates requirements and on early postoperative complications in LTx.

METHODS

Retrospective before-after study comparing two matched cohorts of patients undergoing LTx before (control cohort) and after (intervention cohort) the implementation of a VET-based bleeding algorithm in a single center academic hospital.

RESULTS

After propensity score matching, we included 94 patients in each cohort. Patients in intervention cohort received significantly less blood products, fresh frozen plasma (FFP), and cryoprecipitate (p < 0.001 for each), while the amount of fibrinogen concentrate used was significantly higher (p < 0.001). Postoperatively, intervention cohort patients had significantly lower postoperative hemoglobin and fibrinogen levels and longer prothrombin time compared to control cohort. There were no significant differences in red blood cells transfusions, intraoperative bleeding, early postoperative complications, and short term survival.

CONCLUSIONS

The implementation of a VET-guided bleeding algorithm decreases allogenic blood products requirements, mainly FFP use and allows a more restrictive management of coagulopathy in patients with chronic liver disease undergoing LTx.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

The strengths and weaknesses of viscoelastic testing compared to traditional coagulation testing

Optimized acute bleeding management requires timely and reliable laboratory testing to detect and diagnose coagulopathies and guide transfusion therapy. Conventional coagulation tests (CCT) are inexpensive with minimal labor requirements, but CCTs may have delayed turnaround times. In addition, abnormal CCT values may not reflect in vivo coagulopathies that require treatment and may lead to overtransfusion. The use of viscoelastic testing (VET) has been rapidly expanding and is recommended by several recent bleeding guidelines. This review is intended to compare CCT to VET, review the strengths and weaknesses of both approaches, and evaluate and summarize the clinical studies that compared CCT-based and VET-based transfusion algorithms. Most studies of CCT vs VET transfusion algorithms favor the use of VET in the management of massively bleeding patients due to reductions in blood product utilization, bleeding, costs, and lengths of stay.

Anaesthetic-surgical guide in the treatment of ascending aorta and surgery of the ascending aorta and aortic arch. Consensus document of the Spanish Society of Cardiovascular and Endovascular Surgery and the Sociedad of Anaesthesiology, Resuscitation and Pain Therapy

Aortic pathology is always a challenge for the clinician, and must be diagnosed and treated by a multidisciplinary team due to the technical and technological complexity of the resources used. Ongoing efforts to implement a systematic, protocolized approach involving "Aortic teams" made up of cardiologists, cardiac surgeons, vascular surgeons, anaesthesiologists and radiologists, among others are now leading to improved outcomes. The aim of this consensus document drawn up by the Aortic working groups of the Spanish Society of Anaesthesiology, Resuscitation and Pain Therapy (SEDAR) and the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) is to disseminate a set of working protocols. The latest consensus document of the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society for Vascular Surgery (ESVS) define the concept of "AORTIC TEAM"(1). The aortic team should be closely involved from diagnosis to treatment and finally follow-up, and should be formed of cardiac and vascular surgeons working together with anaesthesiologists, cardiologists, radiologists and geneticists. Treatment of aortic pathologies should be centralised in large centres, because this is the only way to effectively understand the natural course of the disease, provide the entire range of treatment options under one umbrella and treat potential complications. A streamlined emergent care pathway (24/7 availability), adequate transportation and transfer capabilities, as well as rapid activation of the multidisciplinary team must be available. In light of the complexity and constant evolution of therapeutic options, we present this first version of the Anaesthesiology and surgical guidelines for surgery of the ascending aorta and aortic arch. Some questions will no doubt remain unanswered, and future versions will include new techniques that, though implemented in some centres, are still not widely recommended.

Rotational thromboelastometry and conventional coagulation tests in patients undergoing major cardiac or aortic surgery: a retrospective single-center cohort study

Algorithms for treatment of diffuse bleeding in cardiac surgery are based on intervention thresholds of coagulation tests, such as rotational thromboelastometry (ROTEM) or conventional laboratory tests. The relationship between these two approaches is unclear in patients with increased risk of coagulation abnormalities. We retrospectively analyzed the data of 248 patients undergoing major cardiac and/or aortic surgery. ROTEM and conventional laboratory tests were performed simultaneously after termination of cardiopulmonary bypass and protamine administration to investigate the extrinsic and intrinsic system, and to determine deficiencies in platelets and fibrinogen. We evaluated the association between ROTEM and conventional tests by linear regression analysis and compared the frequency of exceeding established thresholds for clinical intervention. Significant linear associations between ROTEM 10 min after the start of coagulation, and plasma fibrinogen concentration or platelet count (FIBTEM A10, R² = 0.67, p < 0.001; EXTEM A10, R² = 0.47, p < 0.001) were obtained. However, the 95% prediction intervals exceeded clinically useful ranges (92–233 mg/dL fibrinogen at the intervention threshold of FIBTEM A10 = 10 mm; 14 × 10³–122 × 10³/µL platelets at the intervention threshold of EXTEM A10 = 40 mm). The association between EXTEM and INR (R² = 0.23), and INTEM and aPTT (R² = 0.095) was poor. The frequency of exceeding intervention thresholds and, consequently, of triggering treatment, varied markedly between ROTEM and conventional tests (p < 0.001 for all comparisons). The predictability of conventional coagulation test results by ROTEM is limited, thus hampering the interchangeability of methods in clinical practice.

Effect of an assessment of fibrin-based rotational thromboelastometry on blood transfusion and clinical outcomes in cardiovascular surgery: A cohort study

The clinical importance of viscoelastic testing in patient blood management when performing cardiovascular surgery is increasing. We aimed to examine the effect of a blood transfusion protocol including an assessment of fibrin-based rotational thromboelastometry on transfusion volume, mortality, and bleeding complications in patients undergoing cardiac or thoracic aortic surgery. We retrospectively studied a cohort of 376 consecutive patients who underwent cardiopulmonary bypass before (control group: 150 cardiac and 35 thoracic aortic surgeries) and after (assessment group: 154 cardiac and 37 thoracic aortic surgeries) introducing the fibrin polymerization assessment with thromboelastometry in the blood transfusion protocol. The transfusion volume and clinical outcomes were compared between the control and assessment groups, and the standardized (mean) difference (S[M]D) was calculated as an indicator of statistical effect size. Compared with the control group, the assessment group had a lower total blood transfusion volume (mL) in cardiac (2720 ± 1282 vs. 2034 ± 1330, p < 0.0001, [SMD] = 0.68) and thoracic aortic surgeries (5236 ± 2732 vs. 3714 ± 1768, p < 0.0001, SMD = 0.67). The 1-year mortality rates were 1.9 % and 2.7 % in cardiac and thoracic aortic surgeries, respectively. Significant differences were not observed in the 1-year mortality (3.2 % vs. 1.0 %, p = 0.16, relative risk [RR] = 0.32 with 95 % confidence intervals [CI] = 0.06-1.57, SD = 0.15), re-exploration for bleeding (4.8 % vs. 2.6 %, p = 0.28, RR = 0.53 with 95 % CI = 0.18-1.57, SD = 0.12), and major bleeding (17.3 % vs. 13.0 %, p = 0.31, RR = 0.75 with 95 % CI = 0.46-1.22, SD = 0.12) rates between the control and assessment groups. The assessment of fibrin polymerization with thromboelastometry using the blood transfusion protocol reduced the blood transfusion volume in cardiovascular surgery.

Barriers and facilitators to implementing evidence based bleeding management in Australian Cardiac Surgery Units: a qualitative interview study analysed with the theoretical domains framework and COM-B model

Background

Bleeding during cardiac surgery is a common complication that often requires the transfusion of blood products. The combination of bleeding and blood product transfusion incrementally increases adverse outcomes including infection and mortality. Following bleeding management guideline recommendations could assist with minimising risk but adherence is not high, and the cause for lack of adherence is not well understood. This study aimed to identify barriers and facilitators to practicing and implementing evidenced-based intra-operative, bleeding management in Australian cardiac surgery units.

Methods

We used a qualitative descriptive design to conduct semi-structured interviews with Australian cardiac surgeons, anaesthetists and perfusionists. The Theoretical Domains Framework (TDF) was utilised to guide interviews and thematically analyse the data. Categorised data were then linked with the three key domains of the COM-B model (capability, opportunity, motivation - behaviour) to explore and understand behaviour.

Results

Seventeen interviews were completed. Nine of the 14 TDF domains emerged as significant. Analysis revealed key themes to improving capability included, standardisation, monitoring, auditing and feedback of data and cross discipline training. Opportunity for change was improved with interpersonal and interdepartmental collaboration through shared goals, and more efficient and supportive processes allowing clinicians to navigate unfamiliar business and financial models of health care. Results suggest as individuals, clinicians had the motivation to make change and healthcare organisations have an obligation and a responsibility to partner with clinicians to support change and improve goal directed best practice.

Conclusion

Using a theory-based approach it was possible to identify factors which may be positively or negatively influence clinicians ability to implement best practice bleeding management in Australian cardiac surgical units.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06269-8.

The Year in Coagulation: Selected Highlights from 2020

This is the second annual review in the Journal of Cardiothoracic and Vascular Anesthesia to cover highlights in coagulation for cardiac surgery. The goal of this article is to provide readers with a focused summary from the literature of the prior year's most important coagulation topics. In 2020, this included a discussion covering allogeneic transfusion, antiplatelet and anticoagulant therapy, factor concentrates, coagulation testing, mechanical circulatory support, and the effects of coronavirus disease 2019.

Effects of implementing rotational thromboelastometry in cardiac surgery: A retrospective cohort study

Since 2013, rotational thromboelastometry has been available in our hospital to assess coagulopathy. The aim of the study was to retrospectively evaluate the effect of thromboelastometry testing in cardiac surgery patients. Altogether 177 patients from 2012 and 177 patients from 2014 were included. In 2014, the thromboelastometry testing was performed on 56 patients. The mean blood drainage volume decreased and the number of patients receiving platelets decreased between 2012 and 2014. In addition, the use of fresh frozen plasma units decreased, and the use of prothrombin complex concentrate increased in 2014. When studied separately, the patients with a thromboelastometry testing received platelets, fresh frozen plasma, fibrinogen and prothrombin complex concentrate more often, but smaller amounts of red blood cells. In conclusion, after implementing the thromboelastometry testing to the practice, the blood products were given more cautiously overall. The use of thromboelastometry testing was associated with increased possibility to receive coagulation product transfusions. However, it appears that thromboelastometry testing was mostly used to assist in management of major bleeding.

Thromboelastometry-guided anticoagulation reversal in a patient with ventricular assist device with intracranial hemorrhage

Intracranial hemorrhage (ICH) is a known complication in patients with ventricular assist devices (VAD). We present a case of a 42-year-old male with a VAD and on warfarin who presented to the emergency department with ICH necessitating anticoagulant reversal. An attenuated dose of 15 units/kg of 4-factor prothrombin complex-concentrates (4F-PCC) was given and the patient's coagulation profile was subsequently assessed using rotational thromboelastometry (ROTEM®) to determine appropriateness of reversal. ROTEM® analysis showed adequate reversal at the time of assessment and the patient ultimately returned home without further functional deficits, highlighting the role of ROTEM® to guide anticoagulation reversal in the VAD patient population.

Current perspective on fibrinogen concentrate in critical bleeding

INTRODUCTION

. Massive hemorrhage continues to be a treatable cause of death. Its management varies from prefixed ratio-driven administration of blood components to goal-directed therapy based on point-of-care testing and administration of coagulation factor concentrates.

AREAS COVERED

. We review the current role of fibrinogen concentrate (FC) for the management of massive hemorrhage, either administered without coagulation testing in life-threatening hemorrhage, or within an algorithm based on viscoelastic hemostatic assays and plasma fibrinogen level. We identified relevant guidelines, meta-analyzes, randomized controlled trials, and observational studies that included indications, dosage, and adverse effects of FC, especially thromboembolic events.

EXPERT OPINION

. Moderate- to high-grade evidence supports the use of FC for the treatment of severe hemorrhage in trauma and cardiac surgery; a lower grade of evidence is available for its use in postpartum hemorrhage and end-stage liver disease. Pre-emptive FC administration in non-bleeding patients is not recommended. FC should be administered early, in a goal-directed manner, guided by early amplitude of clot firmness parameters (A5- or A10-FIBTEM) or hypofibrinogenemia. Further investigation is required into the early use of FC, as well as its potential advantages over cryoprecipitate, and whether or not its administration at high doses leads to a greater risk of adverse events.

Implementation of Perioperative Point-of-Care Platelet Function Analyses Reduces Transfusion Requirements in Cardiac Surgery: A Retrospective Cohort Study

Background Platelet dysfunction is a common cause of bleeding, perioperative blood transfusion, and surgical re-exploration in cardiac surgical patients. We evaluated the effect of incorporating a platelet function analyzer utilizing impedance aggregometry (Multiplate, Roche, Munich, Germany) into our local transfusion algorithm on the rate of platelet transfusion and postoperative blood loss in patients undergoing coronary artery bypass grafting (CABG) surgery.

Methods Data were collected on patients undergoing CABG surgery from January 2015 to April 2017. Patients who underwent surgery before and after introduction of this algorithm were classified into prealgorithm and postalgorithm groups, respectively. The primary outcome was the rate of platelet transfusion before and after implementation of the Multiplate-based transfusion algorithm. Secondary outcomes included transfusion rate of packed red blood cells, postoperative blood loss at 12 and 24 hours, length of stay in the intensive care unit, and the hospital and mortality.

Results A total of 726 patients were included in this analysis with 360 and 366 patients in the pre- and postalgorithm groups, respectively. Transfusion rates of platelets (p = 0.01) and packed red blood cells (p = 0.0004) were significantly lower following introduction of the algorithm in patients (n = 257) who had insufficient time to withhold antiplatelet agents. Receiver operating characteristic curves defined optimal cutoff points of arachidonic acid and adenosine diphosphate assays on the Multiplate to predict future platelet transfusion were 23AU and 43AU, respectively.

Conclusions The introduction of a Multiplate-based platelet transfusion algorithm showed a statistically significant reduction in the administration of platelets to patients undergoing urgent CABG surgery.

Bleeding Management Practices of Australian Cardiac Surgeons, Anesthesiologists and Perfusionists: A Cross-Sectional National Survey Incorporating the Theoretical Domains Framework (TDF) and COM-B Model

Purpose

Excessive bleeding is an acknowledged consequence of cardiac surgery, occurring in up to 10% of adult patients. This clinically important complication leads to poorer patient outcomes. Clinical practice guidelines are available to support best practice however variability in bleeding management practice and related adverse outcomes still exist. This study had two objectives: 1) to gain insight into current bleeding management practice for adult cardiac surgery in Australia and how that compared to guidelines and literature; and 2) to understand perceived difficulties clinicians face implementing improvements in bleeding management.

Methods

A national cross-sectional questionnaire survey was utilized. Perspectives were sought from cardiac surgeons, cardiac anesthesiologists and perfusionists. Thirty-nine closed-ended questions focused on routine bleeding management practices to address pre and intra-operative care. One open-ended question was asked; “What would assist you to improve bleeding management with cardiac surgery patients?” Quantitative data were analysed with SPSS. Qualitative data were categorized into the domains of the Theoretical Domains Framework; the domains were then mapped to the COM-B model.

Results

Survey responses from 159 Anesthesiologists, 39 cardiac surgeons and 86 perfusionists were included (response rate 37%). Four of the recommendations queried in this survey were reported as routinely adhered to < 50% of the time, 9 queried recommendations were adhered to 51–75% of the time and 4 recommendations were routinely followed >76% of the time.

Conclusion

There is a wide variation in peri-operative bleeding management practice among cardiac anaesthesiologists, surgeons and perfusionists in Australian cardiac surgery units. Conceptualizing factors believed necessary to improve practice with the TDF and COM-B model found that bleeding management could be improved with a standardized approach including; point of care diagnostic assays, a bleeding management algorithm, access to concentrated coagulation factors, cardiac surgery specific bleeding management education, multidisciplinary team agreement and support, and an overarching national approach.

The stressed vascular barrier and coagulation - The impact of key glycocalyx components on in vitro clot formation

INTRODUCTION

A functional vascular barrier controlling leukocyte recruitment into the perivascular space relies on an intact endothelial glycocalyx (EGX). Critical disease states such as sepsis or trauma can induce massive shedding of EGX components into the blood stream. Previous studies have shown that high blood levels of EGX components are correlated with bleeding in patients. The mechanism behind that observation remains to be fully elucidated.

MATERIAL AND METHODS

The EGX components syndecan-1 (S1), hyaluronic acid (HA) and heparan sulfate (HS) were added to blood samples of 10 healthy male volunteers separately in three distinct concentrations to mimic three severity levels of in vitro EGX shedding. We analyzed spiked blood samples for leukocyte derived reactive oxygen species (ROS) release as a measure for innate immune activation and evaluated the impact on coagulation using clinical standard coagulation tests (SCTs) as well as rotational thrombelastometry (ROTEM®).

RESULTS

Whereas ROS formation by polymorphonuclear leukocytes (PMN) was unaltered by all three substances, high concentrations of HS showed prolonged aPTT and TT compared to controls and S1 or HA. Changes in ROTEM® were discrete and mostly within normal range of values but analyses showed a significant reduction of clot firmness and formation by all EGX components compared to controls. Furthermore, alterations by HA and HS were dose dependent. Only HS showed a heparin like effect supporting the findings of SCTs.

CONCLUSIONS

All EGX components interfere with clot formation and strength. HS mimics heparin effects in ROTEM® that confirm detectable alterations of standard coagulation tests.

Thromboelastography or rotational thromboelastometry for bleeding management in adults undergoing cardiac surgery: a systematic review with meta-analysis and trial sequential analysis

Background

Severe bleeding and massive transfusion of blood products may be associated with increased morbidity and mortality of cardiac surgery. A transfusion algorithm incorporating thromboelastography (TEG) or rotational thromboelastometry (ROTEM) can help to determine the appropriate time and target for the use of hemostatic blood products, which may thus reduce the quantity of blood loss as well as blood products transfused.

Methods

We conducted meta-analysis and trial sequential analysis to evaluate the effects of TEG or ROTEM-guided transfusion algorithms vs. standard treatments for patients undergoing cardiac surgery with cardiac pulmonary bypass.

Results

Nineteen studies with a total of 15,320 participants, including 13 randomized controlled trials (RCTs), were included. All-cause mortality was not reduced either in overall studies or in RCTs. Blood loss volume was reduced by 132 mL in overall studies [mean difference (MD): -132.46, 95% CI: -207.49, -57.43; I² =53%, P<0.01], and by 103 mL in RCTs (MD: -103.50, 95% CI: -156.52, -50.48; I² =0%, P<0.01). The relative risks (RRs) in RCTs were 0.89 (95% CI: 0.80-0.98; I² =0%, P=0.02) for red blood cells transfusion, 0.59 (95% CI: 0.42-0.82; I² =55%, P<0.01) for fresh frozen plasma transfusion, and 0.81 (95% CI: 0.74-0.90; I² =0%, P<0.01) for platelet transfusion, respectively. Trial sequential analysis of continuous data on blood loss and dichotomous outcomes on transfusion of blood products suggested the benefits of a TEG/ROTEM-guided algorithm.

Conclusions

TEG or ROTEM-guided transfusion strategies may reduce blood loss volume and the transfusion rates in adult patients undergoing cardiac surgery.