Validity of Thromboelastometry for Rapid Assessment of Fibrinogen Levels in Heparinized Samples During Cardiac Surgery: A Retrospective, Single-center, Observational Study

Comparison of the Quantra QPlus and ROTEM Goal-Directed Transfusion Protocols in Cardiothoracic Surgery Patients: A Prospective Observational Study

OBJECTIVES

To compare the designed treatment protocols for the Quantra QPlus and rotational thromboelastometry (ROTEM) with regard to transfusion advice.

DESIGN

Prospective observational study.

SETTING

Maastricht University Medical Center, The Netherlands.

PARTICIPANTS

Adults with elective cardiopulmonary bypass surgery with a ROTEM test.

INTERVENTIONS

ROTEM tests were performed postoperatively for standard monitoring of coagulation status and clinical decision making. Simultaneously, a concurrent sample was analyzed for the Quantra QPlus.

MEASUREMENTS AND MAIN RESULTS

A total of 100 samples were analyzed using both the ROTEM and Quantra QPlus. Agreement between the transfusion advice for the ROTEM and Quantra QPlus protocols were compared using Cohen κ values for i.a. fibrinogen, platelet concentrates, and fresh frozen plasma (FFP). The agreement between ROTEM and Quantra QPlus was poor for overall transfusion (0.174) and fibrinogen transfusion (0.300). The agreement of cutoff values for fibrinogen clot stiffness for the Quantra QPlus and EXTEM A10 for the ROTEM was poor (0.160). The fibrinogen clot stiffness and FIBTEM A10 had a moderate agreement (0.731). A Cohen κ could not be calculated for the agreement of protamine, thrombocytes, FFP or cutoff values for these transfusions since frequencies included zero in these cases. The Quantra QPlus transfusion protocol advises transfusion in many non-bleeders, adjustments appear to be necessary. In a small group of cases in which clinically relevant blood loss was observed, the Quantra QPlus advised administration of transfusion products, whereas the ROTEM tests did not.

CONCLUSION

ROTEM-guided and Quantra-guided transfusion did not correspond in this patient group, and agreement was moderate at best. Specificity and sensitivity for transfusion within protocols were heterogeneous between the methods. More clinical research in high-bleeding risk populations is needed to determine the clinical impact of the different protocols.

Standardized in vitro bleeding tests in a non-coated novel hybrid prosthesis for frozen elephant trunk demonstrates minimal oozing during full heparinization, supported by clinical data

Introduction

Recent reports have questioned the blood impermeability of the novel frozen elephant trunk (FET) device E-vita Open NEO© (EO-NEO). Therefore, standardized in vitro bleeding tests using porcine heparinized blood were performed, as well as stress testing on the blood tightness of the collar suture line, to investigate this observation.

Material and methods

EO-NEO prostheses were examined in vitro for blood permeability in three test series. Initially, antegrade perfusion with heparinized porcine blood [activated clotting time (ACT) of 500 s, with a 60 min duration] was performed, followed by ante/retrograde testing via the EO-NEO side port. Testing of the collar suture line under a tension of 10 Newton (N) within a suspension device (blood pressure 120 mmHg, ACT of 560 s, 1 min duration) was carried out with the suture material force fiber white (FFWs) yarn, using standard fixation (5 stitches/cm), FFWh yarn in hemostatic fixation (15 stitches/cm), and flow weave yarn (FWYh).

Results

Blood permeability testing of EO-NEO through the prosthetic lumen or via the side port demonstrated minor leakage without statistical difference between the standard and hemostatic suture lines or suture materials used, or positioning on the crimped or tapered portion (p > 0.05). The specific collar anastomosis testing demonstrated leakage volumes of 140 ml/min for FFWs vs. 16 ml/min for FFWh (p = 0.02), vs. 9 ml/min with the FWYh (p = 0.01).

Conclusion

Different blood leakage tests showed minimal oozing and no difference in blood loss through the fabric and different collar suture lines, but unphysiological pressurized retrograde perfusion of the collar region showed significantly less leakage using FWYh and FFWh, prompting production modification of EO-NEO. Clinical results confirmed low blood loss using this novel FET device.

Basic Principles of Rotational Thromboelastometry (ROTEM®) and the Role of ROTEM-Guided Fibrinogen Replacement Therapy in the Management of Coagulopathies

Rotational thromboelastometry (ROTEM) is a viscoelastic method, which provides a graphical and numerical representation of induced hemostasis in whole blood samples. Its ability to quickly assess the state of hemostasis is used in the management of bleeding from a variety of causes. The separate activation of particular parts of hemocoagulation in INTEM, EXTEM, and FIBTEM tests allows for a more comprehensive and faster evaluation of the missing component of hemostasis followed by targeted therapy. One of the most common cause of coagulopathy is trauma-induced coagulopathy. Fibrinogen replacement therapy by ROTEM allows for the use of a standard dosage of fibrinogen, which has been shown to be successful in preventing dilutional coagulopathy following colloid and crystalloid replacement and excessive amount of allogeneic blood transfusions. The best reflection of fibrinogen activity is observed in the FIBTEM assay, where fibrinogen replacement therapy is recommended at an MCF (maximum clot firmness) of FIBTEM < 10 mm and FIBTEM A10 < 7 mm. ROTEM also plays an important role in the diagnostic and management of inherited fibrinogen disorders. These can be manifested by bleeding complications, where changes in the MCF parameter are the most useful tool for assessing the effectiveness of fibrinogen replacement therapy. ROTEM-guided bleeding management algorithms effectively reduce the number of transfusions, healthcare costs, and complications, leading to the improvement of patient safety and overall health.

Validity and Utility of Early Parameters in TEG6s Platelet Mapping to Assess the Coagulation Status During Cardiovascular Surgery With Cardiopulmonary Bypass

Background The aim of this retrospective observational study was to explore the early predictive parameters for maximum amplitudein the kaolin with heparinase (HKH) assay (MA_HKH) of TEG6s Platelet Mapping in cardiovascular surgery including cardiopulmonary bypass (CPB) period. The relationship between each parameter of the assay and laboratory data was also assessed. Methods We included the patients who underwent TEG6s Platelet Mapping during cardiovascular surgery under CPB between November 2021 and May 2022. The correlation between MA_HKH and the early parameters was assessed. The association between each parameter of Platelet Mapping and a combination of fibrinogen concentration > 150 mg/dL and platelet count > 100,000µL was also evaluated by the receiver operating characteristic (ROC) curve. Results In 23 patients who underwent TEG6s Platelet Mapping during the study period, 62 HKH assay data including 59 pairs of data (HKH assay and laboratory data) were analyzed. K and angle, but not R, were significantly correlated with MA_HKH (r [95% CI]: -0.90 [-0.94, -0.83], p < 0.0001 for K, and 0.87 [0.79, 0.92], p < 0.0001 for angle). Furthermore, ROC curves suggested that these parameters predicted a combination of fibrinogen concentration > 150 mg/dL and platelet count > 100,000/µL with high accuracy. Similar results were confirmed in the heparinized blood samples obtained during CPB. Conclusion These findings suggest that not only MA_KHK but also K and angle, which are early parameters in the HKH assay, provide clinically significant information that will facilitate rapid decision-making regarding coagulation strategies during cardiovascular surgery including the CPB period.

An audit of the diagnostic accuracy of the ROTEM®sigma for the identification of hypofibrinogenaemia in cardiac surgical patients

The ROTEM®delta (TEM Innovations GmbH, Munich, Germany) has been used extensively worldwide for the assessment of coagulation in cardiac surgical patients. Recently, a new cartridge-based ROTEM device (ROTEM®sigma, TEM Innovations GmbH, Munich, Germany) has become available. In this paper we report an audit of the diagnostic accuracy of the ROTEM sigma for the identification of hypofibrinogenaemia in cardiac surgical patients. We hypothesised that the diagnostic accuracy of the ROTEMsigma for the identification of hypofibrinogenaemia would be in a similar range to that previously reported for the ROTEMdelta. Simultaneous blood samples for Clauss laboratory fibrinogen and ROTEMsigma FIBTEM measurements were obtained immediately after heparin reversal post-cardiopulmonary bypass in 200 adult cardiac surgical patients. The sensitivity, specificity, and positive and negative predictive values for FIBTEM A5 and A10 for the identification of hypofibrinogenaemia (Clauss fibrinogen <1.5 g/l) were calculated. The prevalence of hypofibrinogenaemia across the 200 patients was 8%. The mean sensitivity and specificity of FIBTEM A10 ≤8 mm for the identification of hypofibrinogenaemia were 0.75 and 0.90 respectively, which are in a similar range to that reported in several previous studies using the ROTEMdelta. For FIBTEM A5 ≤6 mm the values were 0.63 and 0.98 respectively. The predictive values were also in a similar range to those previously reported for the ROTEMdelta, with low false negative rates (2% for A10 ≤8 mm; 3% for A5 ≤6 mm). These findings support the use of the ROTEMsigma as an alternative to the ROTEMdelta for the identification of hypofibrinogenaemia post-cardiopulmonary bypass in cardiac surgical patients. However, further studies are required in other settings.

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.

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.

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.

Using Thromboelastography to Predict Blood Loss After Off-Pump Coronary Artery Bypass Grafting

Objective

This study aims to investigate the value of thromboelastography (TEG) in predicting blood loss, and its relationship with blood transfusion demand, during the perioperative period in off-pump coronary artery bypass grafting (OPCABG).

Methods

The data of 398 patients undergoing OPCABG were retrospectively analyzed. Blood was drawn before anesthesia induction (T1) and at 10 minutes after heparin neutralization (T2) for further TEG detection. The patients were divided into two groups based on the results at T2: a TEG normal group and a TEG abnormal group. Logistic regression analysis was used to predict the related factors contributing to the significant increase in perioperative blood loss (more than 20% of the estimated blood volume).

Results

There were 277 (69.6%) patients in the TEG normal group and 121 (30.4%) in the TEG abnormal group. Compared with the TEG normal group, the volume of blood loss, red blood cell count, and volume of plasma transfusion in the TEG abnormal group significantly increased within 24 hours after surgery. The results of the logistic regression analysis identified the use of clopidogrel, platelet count at T2, fibrinogen level at T2, and abnormality in TEG value as independent predictors for the significant increase in perioperative blood loss (P < 0.001).

Conclusion

The abnormality in TEG value after heparin neutralization is correlated with massive hemorrhage and blood transfusion during the perioperative period in OPCABG. TEG detection can assist in clinical treatment and reduce the volume of blood lost in a hemorrhage and the volume of blood required in a transfusion during OPCABG.

Anesthetic Considerations for Transcarotid Artery Revascularization: Experience and Review of Forty Cases From a Single Medical Center

Transcarotid artery revascularization (TCAR) procedure is a novel hybrid surgical modality in treating carotid stenosis. Understanding the various steps of the TCAR and the unique challenges involved in the anesthetic management is essential for the successful conduct of anesthesia. In this article, we discuss the overview of the key issues relevant to the anesthetic management and strategies from our experience. We present the data on anesthetic management and outcomes of 40 patients who underwent TCAR procedure at our institute between June 2018 and February 2020. Electronic medical records were retrospectively reviewed and relevant demographic, clinical, and laboratory data were collected. All our patients had general anesthesia with an endotracheal tube utilizing standard American Society of Anesthesiology (ASA) monitoring along with intra-arterial blood pressure monitoring and cerebral oximetry.

The mean age of our patients was 73.6 ± 7.58 years. Fifteen (37.5 %) patients had significant co-morbidities, thus classified as ASA 4 and 10 (25%) patients were on at least three antihypertensives (beta-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, loop diuretics, thiazides). Thirty-four (85%) patients were considered to have symptomatic carotid stenosis which was the predominant indication for the TCAR procedure. Patients who had episodes of transient ischemic attack (TIA) or a cerebrovascular accident (CVA) documented by a computerized tomography (CT) scan of the brain and/or residual weakness are considered symptomatic. Thirty-six (90%) of our patients received a bolus dose of 0.2 - 0.4 mg of glycopyrrolate for maintaining heart rate of around 70 beats per minute (BPM) and 38 (95%) received phenylephrine infusion during the carotid clamp to maintain blood pressure between 140 and 160 mm Hg systolic or at patients’ baseline. Twenty-one (52.5%) patients needed antihypertensives such as hydralazine ( 10-20 mg) or beta-blockers such as labetalol (10-20 mg) at the time of emergence from anesthesia to mitigate hemodynamic response during extubation. The mean blood loss was 74 ml ± 33.19 ml, and none of our patients received blood transfusion during the perioperative period. The mean duration of anesthesia was 202.6 ± 27.85 minutes, and the mean length of hospital stay was 1.5 ± 0.97 days.

A thorough preoperative examination with specific attention to the preoperative neurological deficits and cardiopulmonary reserve is important for the meticulous management of intraoperative hemodynamics. Intraoperative administration of glycopyrrolate and the use of vasopressors to maintain optimal hemodynamics to ensure cerebral perfusion during the perioperative period should be considered. The anesthetic goals of carotid revascularization (TCAR) are perioperative hemodynamic stability and early evaluation of neurological status in the immediate postoperative period.

"TEG talk": expanding clinical roles for thromboelastography and rotational thromboelastometry

Viscoelastic assays (VEAs) that include thromboelastography and rotational thromboelastometry add value to the investigation of coagulopathies and goal-directed management of bleeding by providing a complete picture of clot formation, strength, and lysis in whole blood that includes the contribution of platelets, fibrinogen, and coagulation factors. Conventional coagulation assays have several limitations, such as their lack of correlation with bleeding and hypercoagulability; their inability to reflect the contribution of platelets, factor XIII, and plasmin during clot formation and lysis; and their slow turnaround times. VEA-guided transfusion algorithms may reduce allogeneic blood exposure during and after cardiac surgery and in the emergency management of trauma-induced coagulopathy and hemorrhage. However, the popularity of VEAs for other indications is driven largely by extrapolation of evidence from cardiac surgery, by the drawbacks of conventional coagulation assays, and by institution-specific preferences. Robust diagnostic studies validating and standardizing diagnostic cutoffs for VEA parameters and randomized trials comparing VEA-guided algorithms with standard care on clinical outcomes are urgently needed. Lack of such studies represents the biggest barrier to defining the role and impact of VEA in clinical care.

Diagnostic accuracy of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients: A systematic review

Hypofibrinogenaemia during cardiac surgery may increase blood loss and bleeding complications. Viscoelastic point-of-care tests provide more rapid diagnosis than laboratory measurement, allowing earlier treatment. However, their diagnostic test accuracy for hypofibrinogenaemia has never been reviewed systematically. We aimed to systematically review their diagnostic test accuracy for the identification of hypofibrinogenaemia during cardiac surgery. Two reviewers assessed relevant articles from seven electronic databases, extracted data from eligible articles and assessed quality. The primary outcomes were sensitivity, specificity and positive and negative predictive values. A total of 576 articles were screened and 81 full texts were assessed, most of which were clinical agreement or outcome studies. Only 10 diagnostic test accuracy studies were identified and only nine were eligible (ROTEM delta 7; TEG5000 1; TEG6S 1, n = 1820 patients) (ROTEM, TEM International GmbH, Munich, Germany; TEG, Haemonetics, Braintree, MA, USA). None had a low risk of bias. Four ROTEM studies with a fibrinogen threshold less than 1.5–1.6 g/l and FIBTEM threshold A10 less than 7.5–8 mm had point estimates for sensitivity of 0.61–0.88; specificity 0.54–0.94; positive predictive value 0.42–0.70; and negative predictive value 0.74–0.98 (i.e. false positive rate 30%–58%; false negative rate 2%–26%). Two ROTEM studies with higher thresholds for both fibrinogen (<2 g/l) and FIBTEM A10 (<9.5 mm) had similar false positive rates (25%–46%), as did the two TEG studies (15%–48%). This review demonstrates that there have been few diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients. The studies performed so far report false positive rates of up to 58%, but low false negative rates. Further diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia are required to guide their better use during cardiac surgery.

Clotting functional stability of withdrawing blood in storage for acute normovolemic hemodilution: a pilot study

Purpose

This study was conducted to time-course changes of clotting function of withdrawing blood for acute normovolemic hemodilution (ANH).

Methods

Twelve enrolled patients who underwent ANH from August, 2018 to January, 2019. Blood was withdrawn into blood collection pack and shaken at 60–80 rpm for 24 h in room temperature. Clot formation was evaluated using rotational thromboelastometry (ROTEM™) just after blood withdrawal (control) and 4, 8, 12 and 24 h after blood withdrawal. We compared with the control value and each value of extrinsically-activated test with tissue factor (EXTEM), intrinsically-activated test using ellagic acid (INTEM) and fibrin-based extrinsically activated test with tissue factor (FIBTEM).

Results

Maximum clot firmness (MCF) of FIBTEM did not change significantly. MCF of EXTEM was significantly decreased time-dependent manner but all MCF of EXTEM were within a normal range. Maximum percent change in MCF of EXTEM was 12.4% [95% confidence interval (CI): 9.0–15.8%]. The difference in the maximum clot elasticity (MCE) between EXTEM and FIBTEM (MCE_EXTEM−MCE_FIBTEM) was significantly decrease from 8 h after blood withdrawal. Maximum percent change in MCE_EXTEM−MCE_FIBTEM was 30.2% (95% CI:17.6–42.9%) at 24 h after blood withdrawal.

Conclusion

Even though the MCE significantly decreased in a time-dependent manner, MCF of FIBTEM and EXTEM was normal up to 24 h storage. The blood of ANH can use for the purpose of hemostasis at least 8 h stored at room temperature after blood withdrawal. Future studies are needed to elucidate the clinical impact on the patient after delayed transfusion of ANH blood with regard to patient’s hemostasis.

Electronic supplementary material

The online version of this article (10.1007/s00540-020-02856-x) contains supplementary material, which is available to authorized users.

Effect of Fibrinogen Concentrate vs Cryoprecipitate on Blood Component Transfusion After Cardiac Surgery: The FIBRES Randomized Clinical Trial

IMPORTANCE

Excessive bleeding is a common complication of cardiac surgery. An important cause of bleeding is acquired hypofibrinogenemia (fibrinogen level <1.5-2.0 g/L), for which guidelines recommend fibrinogen replacement with cryoprecipitate or fibrinogen concentrate. The 2 products have important differences, but comparative clinical data are lacking.

OBJECTIVE

To determine if fibrinogen concentrate is noninferior to cryoprecipitate for treatment of bleeding related to hypofibrinogenemia after cardiac surgery.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial at 11 Canadian hospitals enrolling adult patients experiencing clinically significant bleeding and hypofibrinogenemia after cardiac surgery (from February 10, 2017, to November 1, 2018). Final 28-day follow-up visit was completed on November 28, 2018.

INTERVENTIONS

Fibrinogen concentrate (4 g; n = 415) or cryoprecipitate (10 units; n = 412) for each ordered dose within 24 hours after cardiopulmonary bypass.

MAIN OUTCOMES AND MEASURES

Primary outcome was blood components (red blood cells, platelets, plasma) administered during 24 hours post bypass. A 2-sample, 1-sided test for the ratio of the mean number of units was conducted to evaluate noninferiority (threshold for noninferiority ratio, <1.2).

RESULTS

Of 827 randomized patients, 735 (372 fibrinogen concentrate, 363 cryoprecipitate) were treated and included in the primary analysis (median age, 64 [interquartile range, 53-72] years; 30% women; 72% underwent complex operations; 95% moderate to severe bleeding; and pretreatment fibrinogen level, 1.6 [interquartile range, 1.3-1.9] g/L). The trial met the a priori stopping criterion for noninferiority at the interim analysis after 827 of planned 1200 patients were randomized. Mean 24-hour postbypass allogeneic transfusions were 16.3 (95% CI, 14.9 to 17.8) units in the fibrinogen concentrate group and 17.0 (95% CI, 15.6 to 18.6) units in the cryoprecipitate group (ratio, 0.96 [1-sided 97.5% CI, -∞ to 1.09; P < .001 for noninferiority] [2-sided 95% CI, 0.84 to 1.09; P = .50 for superiority]). Thromboembolic events occurred in 26 patients (7.0%) in the fibrinogen concentrate group and 35 patients (9.6%) in the cryoprecipitate group.

CONCLUSIONS AND RELEVANCE

In patients undergoing cardiac surgery who develop clinically significant bleeding and hypofibrinogenemia after cardiopulmonary bypass, fibrinogen concentrate is noninferior to cryoprecipitate with regard to number of blood components transfused in a 24-hour period post bypass. Use of fibrinogen concentrate may be considered for management of bleeding in patients with acquired hypofibrinogenemia in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03037424.

The Utility of Thromboelastography to Guide Blood Product Transfusion

OBJECTIVES

To provide an overview of the clot viscoelastic testing technology and to describe its utility in guiding blood product transfusions.

METHODS

A case scenario will be discussed as well as interpretation of thromboelastography (TEG) tracings. In addition, literature examining the utility of viscoelastic testing in guiding patient management and blood product transfusions will be reviewed.

RESULTS

TEG/rotational thromboelastometry (ROTEM) is useful in evaluating clot kinetics in trauma and acutely bleeding patients. TEG/ROTEM parameters are reflective of values measured using standard coagulation assays; however, TEG/ROTEM parameters are more rapidly available and more costly. TEG and ROTEM are used in three main settings: cardiac surgery, liver transplantation, and trauma to assess global hemostasis and administration of blood products.

CONCLUSIONS

TEG/ROTEM can be helpful in guiding resuscitation and blood product transfusion. Several studies have demonstrated a reduction in transfusion of blood components with TEG/ROTEM; however, other studies have suggested that TEG/ROTEM is not clinically effective in guiding transfusion.

Diagnostic performance of thromboelastometry in trauma-induced coagulopathy: a comparison between two level I trauma centres using two different devices

PURPOSE

The implementation of a ROTEM^®-based algorithm requires reliable thresholds to mirror a prothrombin time (PT) ratio > 1.2 and/or a fibrinogen concentration < 1.5 g l^-1. Our goal was to compare the diagnostic performances of two devices (ROTEM^® Sigma and Delta, IL Werfen, Munich, Germany) in two level-I trauma centres for the diagnostic of post-traumatic coagulopathy.

METHODS

We conducted a retrospective analysis of two registries across two periods of time: from September 2014 to December 2015 in Lyon-Sud university trauma centre and from April 2016 to January 2018 in the Grenoble Alps Trauma Centre. Accuracies of EXTEM and FIBTEM assays to detect patients with coagulation disorders were tested for each device using receiver operating characteristic (ROC) analyses.

RESULTS

Within the study period, 74 trauma patients in the Grenoble cohort and 75 trauma patients in the Lyon cohort had concomitant ROTEM^® and standard coagulation testing on admission. No statistically significant difference was found between the two ROC curves for FIBTEM amplitude at 5 min (A5), FIBTEM maximum clot firmness, EXTEM clotting time (CT) and EXTEM A5 for ROTEM^® Sigma and Delta to diagnose post-traumatic coagulation disorders. The best threshold for FIBTEM A5 to predict low fibrinogen concentration was 7 mm for each device. EXTEM CT thresholds to diagnose PT ratio > 1.2 were 78 s and 74 s for ROTEM^® Sigma and Delta, respectively.

CONCLUSIONS

These results suggest that ROTEM^®-based algorithms may be transposed from one trauma centre to another independently of the setting and the ROTEM^® device in use.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

A Low-dose human fibrinogen is not effective in decreasing postoperative bleeding and transfusion requirements during cardiac surgery in case of concomitant clinical bleeding and low FIBTEM values: A retrospective matched study

Background

Studies evaluating the hemostatic effects of fibrinogen administration in cardiac surgery are not conclusive.

Aims

We investigated whether the use of a low-dose human fibrinogen in case of clinical bleeding after protamine administration and concomitant low FIBTEM values is effective in reducing postoperative bleeding. Secondary end-point was to investigate the consumption of allogeneic blood products.

Setting and Design

This was a retrospective matched study conducted at university hospital.

Materials and Methods

Among 2257 patients undergoing surgery with cardiopulmonary (CPB) bypass, 73 patients received a median dose of 1 g human fibrinogen (ROTEM-Fibri group). This group was matched with 73 patients who had not received human fibrinogen (control group) among 390 patients having undergone surgery at the moment FIBTEM analysis was unavailable.

Statistical Analysis

Matching was performed for the type and the presence of redo surgery. McNemar and Wilcoxon paired tests were used to respectively compare the categorical and quantitative variables.

Results

The CPB bypass time was significantly higher in the ROTEM-Fibri group (P = 0.006). This group showed significantly higher bleeding in the first 12 and 24 h postoperatively (P < 0.001) and required significantly more transfusion of blood products (P < 0.001) and surgical revision (P = 0.007) when compared with the control group. There was no significant difference in the number of thromboembolic complications.

Conclusions

These results show that the administration of 1 g of fibrinogen based on low-FIBTEM values and clinical bleeding after protamine administration does not stop bleeding and the need for transfusion of allogeneic blood products.

Effects of fibrinogen and platelet transfusion on coagulation and platelet function in bleeding cardiac surgery patients

BACKGROUND

Excessive bleeding is a significant problem in cardiac surgery. Fibrinogen and platelet concentrate transfusion are used clinically to improve haemostasis and reduce bleeding but little is known about their functional effects on coagulation and platelet function in patients with ongoing bleeding.

METHODS

Forty-two patients with ongoing bleeding after cardiac surgery were included in an observational study. Patients received either fibrinogen concentrate (n = 16), platelet concentrate (n = 12), or both fibrinogen and platelets (n = 14), median doses 2 g fibrinogen and 2 units platelets given at one occasion. Blood samples were collected before and after transfusion. Coagulation (clotting time and clot stability) was analysed with rotational thromboelastometry, and platelet function with impedance aggregometry. In addition, platelet count and fibrinogen concentration was measured. Chest drain output was measured before and after the transfusion.

RESULTS

Fibrinogen infusion resulted in an increase in fibrinogen concentration and clot stability (P = 0.001), but had no effect on platelet aggregation. Platelet transfusion did not significantly affect coagulation, but improved arachidonic acid- and TRAP-induced platelet aggregation (P = 0.017 and 0.034 respectively) and increased platelet count. Combined fibrinogen and platelet transfusion shortened clotting time (P = 0.005) and increased clot stability (P = 0.001), and improved arachidonic acid- and TRAP-induced platelet aggregation (P = 0.004 and 0.016 respectively), and increased fibrinogen concentration and platelet count. The median bleeding volume was 150 (25th-75th percentile 70-240) mL/h before, and 60 (40-110) mL/h after transfusion of fibrinogen and/or platelet concentrate (P < 0.001).

CONCLUSION

The results demonstrate improved coagulation and platelet function following fibrinogen and platelet transfusion in patients bleeding after cardiac surgery.

Next generation viscoelasticity assays in cardiothoracic surgery: Feasibility of the TEG6s system

BACKGROUND

Viscoelastic near-patient assays of global hemostasis have been found useful and cost-effective in perioperative settings. Shortcomings of current systems include substantial laboratory intensity, user-dependent reproducibility, relatively large sample volumes, sensitivity to ambient vibration and limited comparability between techniques and devices. The aim of this study was to assess feasibility of a new, resonance-based viscoelastic whole blood methodology (TEG6s) in cardiac surgery with cardiopulmonary bypass (CPB) and to compare the parameters this system produces with the ROTEM delta system and standard coagulation tests.

METHODS

In a prospective evaluation study, twenty-three consecutive cardiac surgery patients underwent hemostasis management according to current guidelines, using the ROTEM delta system and standard coagulation tests. Blood samples were collected prior to CPB before anesthetic induction (pre-CPB), during CPB on rewarming (CPB), and 10 minutes after heparin reversal with protamine (post-CPB). ROTEM and standard coagulation test results were compared with TEG6s parameters, which were concurrently determined using its multi-channel microfluidic cartridge system.

RESULTS

TEG6s provided quantifiable results pre-CPB and post-CPB, but only R (clotting time) of CKH (kaolin with heparinase) was measurable during CPB (full heparinization). Spearman's correlation coefficient (rs) was 0.78 for fibrinogen levels and MA CFF (functional fibrinogen). Correlation of several TEG6s parameters was good (0.77 to 0.91) with MCF FIBTEM, and poor (<0.56) with prothrombin time and activated partial thromboplastin time (<0.44). Rs with platelet count was moderate (0.70, MA CK; 0.73, MA CRT). Accuracy of MA CFF for detection of fibrinogen deficiency < 1.5 g/L was high (ROC-AUC 0.93).

CONCLUSIONS

The TEG6s system, which is based on resonance viscoelastic methodology, appears to be feasible for POC hemostasis assessment in cardiac surgery. Its correlations with standard coagulation parameters are quite similar to those of ROTEM and there is good diagnostic accuracy for fibrinogen levels lower than 1.5 g/L. During full heparinization, TEG6s testing is limited to R measurement. Larger studies are needed to assess superiority over other POC systems.

Correlation Between ROTEM FIBTEM Maximum Clot Firmness and Fibrinogen Levels in Pediatric Cardiac Surgery Patients

This study evaluated whether rotational thromboelastometry (ROTEM; Tem International GmbH, Munich, Germany) FIBTEM maximum clot firmness (MCF) can be used to predict plasma fibrinogen level in pediatric patients undergoing cardiac surgery. Linear regression was conducted to predict plasma fibrinogen level using FIBTEM MCF (0.05 level of significance). Scatter plot with the regression line for the model fit was created. Fifty charts were retrospectively reviewed, and 87 independent measurements of FIBTEM MCF paired with plasma fibrinogen levels were identified for analysis. Linear regression analysis suggested a significant positive linear relationship (P < .0001) between plasma fibrinogen levels and MCF. Both MCF intercept and slope were significantly correlated with fibrinogen level (P < .0001). The estimated regression equation (predicted fibrinogen = 78.6 + 12.4 × MCF) indicates that a 1-mm increase in MCF raises plasma fibrinogen level by an average of 12.4 mg/dL. The statistically significant positive linear relationship observed between MCF and fibrinogen levels (P < .001) suggests that MCF can be used as a surrogate for fibrinogen level. This relationship is of clinical relevance in the calculation of patient-specific dosing of fibrinogen supplementation in this setting.

Preventing and managing catastrophic bleeding during extracorporeal circulation

The use of extracorporeal circulation for cardiac surgery and extracorporeal life support poses tremendous challenges to the hemostatic equilibrium given its diametric tendency to trigger hyper- and hypocoagulopathy. The necessity of anticoagulant therapy to counteract the hemostatic activation by the extracorporeal circuitry compounded by unfavorable patient and surgical factors significantly increase the risk of catastrophic bleeding in patients who require extracorporeal circulation. Preoperative measures, such as stratification of high-risk bleeding patients, and optimization of the modifiable variables, including anemia and thrombocytopenia, provide a crude estimation of the likelihood and may modify the risk of catastrophic bleeding. The anticipation for catastrophic bleeding subsequently prompts the appropriate preparation for potential resuscitation and massive transfusion. Equally important is intraoperative prevention with the prophylactic application of tranexamic acid, an antifibrinolytic agent that has promising benefits in reduction of blood loss and transfusion. In the event of uncontrolled catastrophic bleeding despite preemptive strategies, all effort must be centered on regaining hemostasis through surgical control and damage control resuscitation to protect against worsening coagulopathy and end organ failure. When control of bleeding is reinstated, management should shift focus from systemic therapy to targeted hemostatic therapy aimed at the potential culprits of coagulopathy as identified by point of care hemostatic testing. This review article outlines the strategies to appropriately intervene using prediction, prevention, preparation, protection, and promotion of hemostasis in managing catastrophic bleeding in extracorporeal circulation.

Thromboelastography and Thromboelastometry in Assessment of Fibrinogen Deficiency and Prediction for Transfusion Requirement: A Descriptive Review

Fibrinogen is crucial for the formation of blood clot and clinical outcomes in major bleeding. Both Thromboelastography (TEG) and Rotational Thromboelastometry (ROTEM) have been increasingly used to diagnose fibrinogen deficiency and guide fibrinogen transfusion in trauma and surgical bleeding patients. We conducted a comprehensive and comparative review on the technologies and clinical applications of two typical functional fibrinogen assays using TEG (FF TEG) and ROTEM (FIBTEM) for assessment of fibrinogen level and deficiency, and prediction of transfusion requirement. Clot strength and firmness of FF TEG and ROTEM FIBTEM were the most used parameters, and their associations with fibrinogen levels as measured by Clauss method ranged from 0 to 0.9 for FF TEG and 0.27 to 0.94 for FIBTEM. A comparison of the interchangeability and clinical performance of the functional fibrinogen assays using the two systems showed that the results were correlated, but are not interchangeable between the two systems. It appears that ROTEM FIBTEM showed better associations with the Clauss method and more clinical use for monitoring fibrinogen deficiency and predicting transfusion requirements including fibrinogen replacement than FF TEG. TEG and ROTEM functional fibrinogen tests play important roles in the diagnosis of fibrinogen-related coagulopathy and guidance of transfusion requirements. Despite the fact that high-quality evidence is still needed, the two systems are likely to remain popular for the hemostatic management of bleeding patients.

An Audit of the Diagnostic Accuracy of Rotational Thromboelastometry for the Identification of Hypofibrinogenaemia and Thrombocytopenia during Cardiopulmonary Bypass

We audited the diagnostic accuracy of ROTEM® (TEM Innovations, GmbH, Munich, Germany) measurements of hypofibrinogenaemia (fibrinogen <1.5 g/l) and thrombocytopenia (platelet count <100 × 109/l) in 200 adult non-transplant patients during cardiopulmonary bypass (CPB). Blood samples were obtained for FIBTEM (assay for the fibrin part of the clot), PLTEM (calculated platelet-specific component), and laboratory measurements simultaneously. Our thresholds for FIBTEM and PLTEM were A10 (clot firmness 10 minutes after clotting time) ≤8 mm, and <35 mm respectively. We also calculated the accuracy of smaller thresholds and earlier indices. We found that FIBTEM A10 ≤8 mm had low sensitivity (0.62) for hypofibrinogenaemia. With the 13% hypofibrinogenaemia prevalence in our sample, the positive predictive value (PPV) was 0.47. In contrast, FIBTEM A10 ≤8 mm had higher specificity (0.90) (negative predictive value [NPV] 0.94). Of the other FIBTEM values analysed, only A5 ≤6 mm had similar or superior accuracy. The PLTEM results were less encouraging (sensitivity 0.81, specificity 0.62). With our prevalence of thrombocytopenia (also 13%), the PPV was only 0.24. However, the NPV was high (0.96). Of the other PLTEM values analysed, only A5 <25 mm had similar or superior accuracy. These findings indicate that during CPB FIBTEM A10 ≤8 mm and PLTEM A10 <35 mm have greater accuracy in identifying the absence of hypofibrinogenaemia and thrombocytopenia respectively than their presence. On the basis of these results we would be reassured by FIBTEM A10 values >8 mm and PLTEM A10 values ≥35 mm, but would continue to use laboratory measurements for confirmation. We would not use FIBTEM A10 ≤8 mm or PLTEM A10 <35 mm values alone to guide replacement therapy unless clinical conditions warranted an immediate decision before laboratory measurements were available.

Protocol for a phase III, non-inferiority, randomised comparison of a new fibrinogen concentrate versus cryoprecipitate for treating acquired hypofibrinogenaemia in bleeding cardiac surgical patients: the FIBRES trial

INTRODUCTION

Coagulopathic bleeding is a serious complication of cardiac surgery to which an important contributor is acquired hypofibrinogenaemia (plasma fibrinogen <1.5-2.0 g/L). The standard intervention for acquired hypofibrinogenaemia is cryoprecipitate, but purified fibrinogen concentrates are also available. There is little comparative data between the two therapies and randomised trials are needed.

METHODS AND ANALYSIS

FIBrinogen REplenishment in Surgery (FIBRES) is a multicentre, randomised (1:1), active-control, single-blinded, phase III trial in adult cardiac surgical patients experiencing clinically significant bleeding related to acquired hypofibrinogenaemia. The primary objective is to demonstrate that fibrinogen concentrate (Octafibrin/Fibryga; Octapharma) is non-inferior to cryoprecipitate. All patients for whom fibrinogen supplementation is ordered by the clinical team within 24 hours of cardiopulmonary bypass will receive 4 g of fibrinogen concentrate or 10 units of cryoprecipitate (dose-equivalent to 4 g), based on random allocation and deferred consent. The primary outcome is total red cell, platelet and plasma transfusions administered within 24 hours of bypass. Secondary outcomes include major bleeding, fibrinogen levels and adverse events within 28 days. Enrolment of 1200 patients will provide >90% power to demonstrate non-inferiority. One preplanned interim analysis will include 600 patients. The pragmatic design and treatment algorithm align with standard practice, aiding adherence and generalisability.

ETHICS AND DISSEMINATION

The study is approved by the local research ethics board and will be conducted in accordance with the Declaration of Helsinki, Good Clinical Practice guidelines and regulatory requirements. Patient consent prior to treatment is waived, as per criteria in the Tri-Council Policy Statement. Results will be published in the scientific/medical literature, and at international congresses. Non-inferiority of purified fibrinogen concentrate would support its use in acquired hypofibrinogenaemia. The results are likely to improve care for cardiac surgical patients experiencing significant bleeding, an understudied yet high-risk population.

TRIAL REGISTRATION NUMBER

NCT03037424; Pre-results.

Position of the French Working Group on Perioperative Haemostasis (GIHP) on viscoelastic tests: What role for which indication in bleeding situations?

PURPOSE

Viscoelastic tests (VETs), thromboelastography (TEG^®) and thromboelastometry (ROTEM^®) are global tests of coagulation performed on whole blood. They evaluate the mechanical strength of a clot as it builds and develops after coagulation itself. The time required to obtain haemostasis results remains a major problem for clinicians dealing with bleeding, although some teams have developed a rapid laboratory response strategy. Indeed, the value of rapid point-of-care diagnostic devices such as VETs has increased over the years. However, VETs are not standardised and there are few recommendations from the learned societies regarding their use. In 2014, the recommendations of the International Society of Thrombosis and Haemostasis (ISTH) only concerned haemophilia. The French Working Group on Perioperative haemostasis (GIHP) therefore proposes to summarise knowledge on the clinical use of these techniques in the setting of emergency and perioperative medicine.

METHODS

A review of the literature.

PRINCIPAL FINDINGS

The role of the VETs seems established in the management of severe trauma and in cardiac surgery, both adult and paediatric. In other situations, their role remains to be defined: hepatic transplantation, postpartum haemorrhage, and non-cardiac surgery. They must be part of the global management of haemostasis based on algorithms defined in each centre and for each population of patients. Their position at the bedside or in the laboratory is a matter of discussion between clinicians and biologists.

CONCLUSION

VETs must be included in algorithms. In consultation with the biology laboratory, these devices should be situated according to the way each centre functions.

Utility of intraoperative rotational thromboelastometry in thoracolumbar deformity surgery

OBJECTIVE Blood loss during surgery for thoracolumbar scoliosis often requires blood product transfusion. Rotational thromboelastometry (ROTEM) has enabled the more targeted treatment of coagulopathy, but its use in deformity surgery has received limited study. The authors investigated whether the use of ROTEM reduces transfusion requirements in this case-control study of thoracolumbar deformity surgery. METHODS Data were prospectively collected on all patients who received ROTEM-guided blood product management during long-segment (≥ 7 levels) posterior thoracolumbar fusion procedures at a single institution from April 2015 to February 2016. Patients were matched with a group of historical controls who did not receive ROTEM-guided therapy according to age, fusion segments, number of osteotomies, and number of interbody fusion levels. Demographic, intraoperative, and postoperative transfusion requirements were collected on all patients. Univariate analysis of ROTEM status and multiple linear regression analysis of the factors associated with total in-hospital transfusion volume were performed, with p < 0.05 considered to indicate statistical significance. RESULTS Fifteen patients who received ROTEM-guided therapy were identified and matched with 15 non-ROTEM controls. The mean number of fusion levels was 11 among all patients, with no significant differences between groups in terms of fusion levels, osteotomy levels, interbody fusion levels, or other demographic factors. Patients in the non-ROTEM group required significantly more total blood products during their hospitalization than patients in the ROTEM group (8.5 ± 4.2 units vs 3.71 ± 2.8 units; p = 0.001). Multiple linear regression analysis showed that the use of ROTEM (p = 0.016) and a lower number of fused levels (p = 0.022) were associated with lower in-hospital transfusion volumes. CONCLUSIONS ROTEM use during thoracolumbar deformity correction is associated with lower transfusion requirements. Further investigation will better define the role of ROTEM in transfusion during deformity surgery.

Intraoperative care for aortic surgery using circulatory arrest

The total circulatory arrest (CA) is necessary to achieve optimal surgical conditions in certain aortic pathologies, especially in those affecting the ascending aorta and aortic arch. During this procedure it is necessary to protect all the organs of ischemia, especially those of the central nervous system and for this purpose several strategies have been developed. The first and most important protective method is systemic hypothermia. The degree of hypothermia and the route of application have been evolving and currently tend to use moderate hypothermia (MH) (20.1-28 °C) associated with unilateral or bilateral selective cerebral perfusion methods. In this way the neurological results are better, the interval of security is greater and the times of extracorporeal circulation are smaller. Even so, it is necessary to take into account that there is the possibility of ischemia in the lower part of the body, especially of the abdominal viscera and the spinal cord, therefore the time of circulatory stop should be limited and not to exceed 80 minutes. Evidence of possible neurological drug protection is very weak and only mannitol, magnesium, and statins can produce some benefit. Inhalational anesthetics and some intravenous seem to have advantages, but more studies would be needed to test their long-term benefit. Other important parameters to be monitored during these procedures are blood glucose, anemia and coagulation disorders and acid-base balance. The recommended monitoring is common in complex cardiovascular procedures and it is of special importance the neurological monitoring that can be performed with several techniques, although currently the most used are Bispectral Index (BIS) and Near-Infrared Spectroscopy (NIRS). It is also essential to monitor the temperature routinely at the nasopharyngeal and bladder level and it is important to control coagulation with rotational thromboelastometry (ROTEM).

Thromboelastometry Versus Rotational Thromboelastography in Cardiac Surgery

Evidence exists on the morbiduty and mortality associated with both massive blood loss and transfusion in cardiac surgical patients. Monitoring of the vesicoelastic properties of blood using rotational thromboelastometry and thromboelsatography (TEG) has been a major step towards ameliorating the risks associated with these 2 evils by providing trageted goal-directed blood product resuscitation. Point of care ROTEM and TEG overcome many of the current limitatons of conventional laboratory coagulation testing. Despite the peaking interest and widespread use there is a lack of consensus whetehr the use of these devices to guide blood product resucistation is associated with a reduction in mortality. Also, both ROTEM and TEG suffer from some limitations resulting in a lack of agreement on the duperiority of one device versus the other. In this concise review we discuss the operational charecteristics of both devices and the pro-side of the use of ROTEM in cardiac surgery backed with the most recent evidence.

Point-of-Care Hemostatic Testing in Cardiac Surgery: A Stepped-Wedge Clustered Randomized Controlled Trial

BACKGROUND

Cardiac surgery is frequently complicated by coagulopathic bleeding that is difficult to optimally manage using standard hemostatic testing. We hypothesized that point-of-care hemostatic testing within the context of an integrated transfusion algorithm would improve the management of coagulopathy in cardiac surgery and thereby reduce blood transfusions.

METHODS

We conducted a pragmatic multicenter stepped-wedge cluster randomized controlled trial of a point-of-care-based transfusion algorithm in consecutive patients undergoing cardiac surgery with cardiopulmonary bypass at 12 hospitals from October 6, 2014, to May 1, 2015. Following a 1-month data collection at all participating hospitals, a transfusion algorithm incorporating point-of-care hemostatic testing was sequentially implemented at 2 hospitals at a time in 1-month intervals, with the implementation order randomly assigned. No other aspects of care were modified. The primary outcome was red blood cell transfusion from surgery to postoperative day 7. Other outcomes included transfusion of other blood products, major bleeding, and major complications. The analysis adjusted for secular time trends, within-hospital clustering, and patient-level risk factors. All outcomes and analyses were prespecified before study initiation.

RESULTS

Among the 7402 patients studied, 3555 underwent surgery during the control phase and 3847 during the intervention phase. Overall, 3329 (45.0%) received red blood cells, 1863 (25.2%) received platelets, 1645 (22.2%) received plasma, and 394 (5.3%) received cryoprecipitate. Major bleeding occurred in 1773 (24.1%) patients, and major complications occurred in 740 (10.2%) patients. The trial intervention reduced rates of red blood cell transfusion (adjusted relative risk, 0.91; 95% confidence interval, 0.85-0.98; P=0.02; number needed to treat, 24.7), platelet transfusion (relative risk, 0.77; 95% confidence interval, 0.68-0.87; P<0.001; number needed to treat, 16.7), and major bleeding (relative risk, 0.83; 95% confidence interval, 0.72-0.94; P=0.004; number needed to treat, 22.6), but had no effect on other blood product transfusions or major complications.

CONCLUSIONS

Implementation of point-of-care hemostatic testing within the context of an integrated transfusion algorithm reduces red blood cell transfusions, platelet transfusions, and major bleeding following cardiac surgery. Our findings support the broader adoption of point-of-care hemostatic testing into clinical practice.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02200419.