What is the optimal management of thromboprophylaxis after liver transplantation regarding prevention of bleeding, hepatic artery or portal vein thrombosis? A systematic review of the literature and expert panel recommendations
Clinical transplantation. 2022;:e14629
BACKGROUND A key tenet of clinical management of patients post liver transplantation (LT) is the prevention of thrombotic and bleeding complications. This systematic review investigated the optimal management of thromboprophylaxis after LT regarding portal vein thrombosis (PVT) or hepatic artery thrombosis (HAT) and prevention of bleeding. METHODS Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Seven databases were used to conduct extensive literature searches focusing on the use of anticoagulation in LT and its impact on the following outcomes: PVT, HAT, and bleeding. (CRD42021244288) RESULTS Of the 2,478 articles/abstracts screened, 16 studies were included in the final review. All articles were critically appraised by a panel of independent reviewers. There was wide variation regarding the anticoagulation protocols used. Thromboprophylaxis with therapeutic doses of heparin/Vitamin K antagonist combination did not decrease the risk of de novo or the recurrence of PVT but was associated with an increased risk of bleeding in some studies. Only the use of aspirin resulted in a small but significant decrease in the incidence of HAT post-LT, yet it did not increase the risk of bleeding. CONCLUSIONS Based on existing data and expert opinion, thromboprophylaxis at therapeutic or prophylactic dose is not recommended for prevention of de novo PVT following LT in patients not at high risk. Aspirin should be considered as the standard of care following LT to prevent HAT. Thromboprophylaxis should be strongly considered in recipients at risk of HAT and PVT following LT. This article is protected by copyright. All rights reserved.
Rotational thromboelastometry reduces blood loss and blood product usage after lung transplantation
The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation. 2021
BACKGROUND The shortage of blood products has become a worldwide problem, especially during the COVID-19 Pandemic. Here, we investigated whether a point of care (POC) approach to perioperative bleeding and coagulopathy based on rotational thromboelastometry (ROTEM) results could decrease perioperative blood loss and the perioperative consumption of blood products during lung transplantation. METHODS Patients undergoing bilateral lung transplantation were randomized into two groups: In the first group, designated the "non POC" group, the management of perioperative bleeding and coagulopathy was based on the clinical experience of the anesthesiologist; in the second group, designated the "POC" group, the management of perioperative bleeding, and coagulopathy was based on the ROTEM results. RESULTS After performing an interim statistical analysis, the project was prematurely terminated as the results were significantly in favor of the POC approach. Data were analyzed for the period January 2018 until June 2020 when 67 patients were recruited into the study. There was significantly decreased perioperative blood loss in the POC group (n = 31 patients) with p = 0.013, decreased perioperative consumption of RBC with p = 0.009, and decreased perioperative consumption of fresh frozen plasma with p < 0.0001 (practically no fresh frozen plasma was used in the POC group) without deteriorating clot formation in secondary and primary hemostasis as compared to the non POC group (n = 36). CONCLUSION POC management of perioperative bleeding and coagulopathy based on ROTEM results is a promising strategy to decrease perioperative blood loss and the consumption of blood products in lung transplantation.
Role of Using a Thromboelastometry-Based Protocol for Transfusion Management in Combined Coronary Artery Bypass Grafting and Valve Surgery: A Randomized Clinical Trail
Indian journal of hematology & blood transfusion : an official journal of Indian Society of Hematology and Blood Transfusion. 2021;37(3):422-429
The aim of this study was to evaluate the impact of using a thromboelastometry-based protocol on transfusion requirements in patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. 80 adult patients scheduled for elective combined CABG and valve surgery were included in this clinical trial study. Patients were randomly allocated to the thromboelastometry (ROTEM) (n = 40) or control groups (n = 40). In the ROTEM group, transfusion was directed according to a thromboelastometry-based protocol. In the control group, transfusion was conducted according to the routine practices including conventional coagulation testing and clinical judgments. Finally, transfusion requirements were compared between groups. Use of thromboelastometry- based protocol resulted in 67% reduction in blood products units' consumption as well as 23% in the percentage of patients transfused. This reduction was especially evident in relation to fresh frozen plasma (FFP) and platelet consumption. No significant differences were found both in the percentage of patients receiving RBC and number of transfused RBC units. Using thromboelastometry tests incorporated a protocol results in reduction of transfusion requirements in patients undergoing elective combined CABG and valve surgery.
Eye tracking metrics and leader's behavioral performance during a post-partum hemorrhage high-fidelity simulated scenario
Advances in simulation (London, England). 2021;6(1):4
BACKGROUND The use of eye tracking in the simulated setting can help improve our understanding of what sources of information clinicians are using as they deliver routine patient care. The aim of this simulation study was to observe the differences, if any, between the eye tracking patterns of leaders who performed best in a simulated postpartum hemorrhage (PPH) high-fidelity scenario, in comparison with those who performed worst. METHODS Forty anesthesia trainees from the University of Catania Medical School were divided into eight teams, to enact four times the same scenario of a patient with postpartum hemorrhage following vaginal delivery. Trainees who were assigned the leader's role wore the eye tracking glasses during the scenario, and their behavioral skills were evaluated by two observers, who reviewed the video recordings of the scenarios using a standardized checklist. The leader's eye tracking metrics, extracted from 27 selected areas of interest (AOI), were recorded by a Tobii Pro Glasses 50 Hz wearable wireless eye tracker. Team performance was evaluated using a PPH checklist. After completion of the study, the leaders were divided into two groups, based on the scores they had received (High-Performance Leader group, HPL, and Low-Performance Leader group, LPL). RESULTS In the HPL group, the duration and number of fixations were greater, and the distribution of gaze was uniformly distributed among the various members of the team as compared with the LPL group (with the exception of the participant who performed the role of the obstetrician). The HPL group also looked both at the patient's face and established eye contact with their team members more often and for longer (P < .05). The team performance (PPH checklist) score was greater in the HPL group (P < .001). The LPL group had more and/or longer fixations of technical areas of interest (P < .05). CONCLUSIONS Our findings suggest that the leaders who perform the best distribute their gaze across all members of their team and establish direct eye contact. They also look longer at the patient's face and dwell less on areas that are more relevant to technical skills. In addition, the teams led by these best performing leaders fulfilled their clinical task better. The information provided by the eye behaviors of "better-performing physicians" may lay the foundation for the future development of both the assessment process and the educational tools used in simulation. TRIAL REGISTRATION Clinical.Trial.Gov ID n. NCT04395963 .
Use of Thromboelastography in the Evaluation and Management of Patients With Traumatic Brain Injury: A Systematic Review and Meta-Analysis
Critical care explorations. 2021;3(9):e0526
Traumatic brain injury is associated with coagulopathy that increases mortality risk. Viscoelastic hemostatic assays such as thromboelastography (Haemonetics SA, Signy, Switzerland) provide rapid coagulopathy assessment and may be particularly useful for goal-directed treatment of traumatic brain injury patients. We conducted a systematic review to assess thromboelastography in the evaluation and management of coagulopathy in traumatic brain injury patients. DATA SOURCES MEDLINE, PubMed Central, Embase, and CENTRAL. STUDY SELECTION Clinical studies of adult patients with traumatic brain injury (isolated or polytrauma) who were assessed by either standard thromboelastography or thromboelastography with platelet mapping plus either conventional coagulation assays or platelet function assays from January 1999 to June 2021. DATA EXTRACTION Demographics, injury mechanism and severity, diagnostic, laboratory data, therapies, and outcome data were extracted for analysis and comparison. DATA SYNTHESIS Database search revealed 1,169 sources; eight additional articles were identified by the authors. After review, 31 publications were used for qualitative analysis, and of these, 16 were used for quantitative analysis. Qualitative and quantitative analysis found unique patterns of thromboelastography and thromboelastography with platelet mapping parameters in traumatic brain injury patients. Patterns were distinct compared with healthy controls, nontraumatic brain injury trauma patients, and traumatic brain injury subpopulations including those with severe traumatic brain injury or penetrating traumatic brain injury. Abnormal thromboelastography K-time and adenosine diphosphate % inhibition on thromboelastography with platelet mapping are associated with decreased survival after traumatic brain injury. Subgroup meta-analysis of severe traumatic brain injury patients from two randomized controlled trials demonstrated improved survival when using a viscoelastic hemostatic assay-guided resuscitation strategy (odds ratio, 0.39; 95% CI, 0.17-0.91; p = 0.030). CONCLUSIONS Thromboelastography and thromboelastography with platelet mapping characterize coagulopathy patterns in traumatic brain injury patients. Abnormal thromboelastography profiles are associated with poor outcomes. Conversely, treatment protocols designed to normalize abnormal parameters may be associated with improved traumatic brain injury patient outcomes. Current quality of evidence in this population is low; so future efforts should evaluate viscoelastic hemostatic assay-guided hemostatic resuscitation in larger numbers of traumatic brain injury patients with specific focus on those with traumatic brain injury-associated coagulopathy.
Utility of Viscoelastic Tests to Predict Flap Thrombosis: A Systematic Review
Plastic and reconstructive surgery. Global open. 2021;9(8):e3769
BACKGROUND Flap thrombosis is a rare but devastating complication in microsurgery. Preoperative identification of patients at increased risk for microvascular thrombosis remains challenging. Viscoelastic testing (VET) provides a comprehensive evaluation of the clotting process and can effectively identify hypercoagulability. However, the utility of VET in microvascular reconstruction remains unclear. METHODS A systematic review of the association between VET and pedicle thrombosis and free flap loss was performed in accordance with Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Identified studies were reviewed independently by two authors for pertinent data. RESULTS Six studies met inclusion criteria. Heterogenous study design and outcome reporting complicated direct comparisons and precluded a formal meta-analysis. Four studies found a statistically significant relationship between VET results and flap thrombosis or flap loss. The maximum clot strength and the fibrinogen-to-platelet ratio (FPR) were key viscoelastic parameters in these studies, both representing a measure of maximal clot strength. Specifically, an elevated FPR (>42%) generated a sensitivity and specificity for flap loss ranging from 57% to 75% and 60% to 82%, respectively. Notably, the negative predictive value for flap failure with a normal preoperative FPR was greater than 90% in all studies reporting a correlation. The remaining two studies reported no predictive value for VET with respect to flap failure or pedicle thrombosis. CONCLUSION The results of this review suggest that VET, particularly parameters relating to clot strength, may help clinicians identify patients at risk for flap thrombosis. However, uncontrolled and heterogenous reporting limit definitive conclusions, and high-quality diagnostic studies are needed to better determine the clinical utility of viscoelastic testing for free flap patients.
A Systematic Review of Thromboelastography Utilization in Vascular and Endovascular Surgery
Journal of vascular surgery. 2021
OBJECTIVE Thromboelastography (TEG) is diagnostic modality that analyzes real-time blood coagulation parameters. Clinically, TEG primarily allows for directed blood component resuscitation among patients with acute blood loss and coagulopathy. The utilization of TEG has been widely adopted in among other surgical specialties; however, its use in vascular surgery is less prominent. We aimed to provide an up-to-date review of TEG utilization in vascular and endovascular surgery. METHODS Using PRISMA guidelines, a literature review with the Medical Subject Headings (MeSH) terms "TEG and arterial events", "TEG and vascular surgery", "TEG and vascular", "TEG and endovascular surgery", "TEG and endovascular", "TEG and peripheral artery disease", "TEG and prediction of arterial events", "TEG and prediction of complications ", "TEG and prediction of thrombosis", "TEG and prediction of amputation", and "TEG and amputation" was performed in Cochrane and PubMed databases to identify all peer-reviewed studies of TEG utilization in vascular surgery, written between 2000-2021 in the English language. The free text and MeSH subheadings search terms included diagnosis, complications, physiopathology, surgery, mortality, and therapy to further restrict the articles. Studies were excluded if they were not in humans or pertaining to vascular or endovascular surgery. Additionally, case reports and studies with limited information regarding TEG utilization were excluded. Each study was independently reviewed by two researchers to assess for eligibility. RESULTS Of the 262 studies identified through the MeSH strategy, 15 studies met inclusion criteria and were reviewed and summarized. Literature on TEG utilization in vascular surgery spanned cerebrovascular disease (n=3), peripheral arterial disease (n=3), arteriovenous malformations (n=1), venous thromboembolic events (n=7), and perioperative bleeding and transfusion (n=1). In cerebrovascular disease, TEG may predict the presence and stability of carotid plaques, analyze platelet function before carotid stenting, and compare efficacy of antiplatelet therapy after stent deployment. In peripheral arterial disease, TEG has been used to predict disease severity and analyze the impact of contrast on coagulation parameters. In venous disease, TEG may predict hypercoagulability and thromboembolic events among various patient populations. Finally, TEG can be utilized in the postoperative setting to predict hemorrhage and transfusion requirements. CONCLUSIONS This systematic review provides an up-to-date summarization of TEG utilization in multiple facets of vascular and endovascular surgery.
Patients undergoing vascular and endovascular surgery (15 studies).
Systematic review to provide an up-to-date summarization of thromboelastography (TEG).
Literature on TEG utilization in vascular surgery spanned cerebrovascular disease (n=3), peripheral arterial disease (n=3), arteriovenous malformations (n=1), venous thromboembolic events (n=7), and perioperative bleeding and transfusion (n=1). In cerebrovascular disease, TEG may predict the presence and stability of carotid plaques, analyse platelet function before carotid stenting, and compare efficacy of antiplatelet therapy after stent deployment. In peripheral arterial disease, TEG has been used to predict disease severity and analyse the impact of contrast on coagulation parameters. In venous disease, TEG may predict hypercoagulability and thromboembolic events among various patient populations.
Viscoelastic Hemostatic Assays and Outcomes in Traumatic Brain Injury: A Systematic Literature Review
World neurosurgery. 2021
BACKGROUND Coagulopathy in Traumatic brain injury (TBI) occurs frequently and is associated with poor outcomes. Conventional coagulation assays (CCA) traditionally used to diagnose coagulopathy are often not time sensitive and do not assess complete hemostatic function. Viscoelastic hemostatic assays (VHA) including thromboelastography (TEG) and rotational thromboelastography (ROTEM) provide a useful rapid and comprehensive point-of-care alternative for identifying coagulopathy, which is of significant consequence in TBI patients with intracranial hemorrhage. METHODS A systematic review was performed in accordance with guidelines for the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to identify studies comparing VHA to CCA in adult TBI patients. The following differences in outcomes were assessed based on ability to diagnose coagulopathy: mortality, need for neurosurgical intervention, and progression of traumatic intracranial hemorrhage (tICH). RESULTS Abnormal R-time, MA, and K value were associated with increased mortality in certain studies but not all studies. This association was reflected across studies utilizing different statistical parameters with different outcome definitions. An abnormal R-time was the only VHA parameter found to be associated with the need for neurosurgical intervention in one study. An abnormal R time was also the only VHA parameter associated with progression of tICH. Overall, many studies also demonstrated abnormal CCAs, mainly activated partial thromboplastin time (aPPT) to be associated with poor outcomes. CONCLUSION Given the heterogenous nature of the available evidence including methodology and study outcomes, the comparative difference between VHA and CCA in predicting rates of neurosurgical intervention, tICH progression, or mortality in TBI patients remains inconclusive.
Comparison between intraoperative bleeding score and ROTEM® measurements to assess coagulopathy during major pediatric surgery
Transfusion and apheresis science : official journal of the World Apheresis Association : official journal of the European Society for Haemapheresis. 2021;:103191
PURPOSE Intraoperative bleeding should be regularly assessed visually to guide coagulation management. Whereas viscoelastic testing with ROTEM® measurement has been proven to be useful in detecting coagulopathies, the visual assessment is not standardized. This study therefore aims to compare a standardized visual assessment with ROTEM® results. METHODS A 5-point bleeding score was created and applied in a recently published randomized controlled trial in major pediatric non-cardiac surgery. This score assesses overall bleeding tendency and the occurrence of diffuse bleeding, aqueous bleeding, bleeding outside the operative field, and the ability to control bleeding. Validity of this score was tested by post hoc comparison to the results of simultaneously performed ROTEM® measurements. RESULTS Signs of coagulopathic bleeding were assessed at 183 time points. Mild to moderate bleeding intensity was judged at 103 time points, in 42 % abnormal ROTEM® traces were obtained simultaneously. When severe bleeding was scored, abnormal ROTEM values occurred in 58 %, and FIBTEM-values were significantly lower than in the "no bleeding group". Altogether, the correlation between bleeding score and ROTEM® measurements was not significant. CONCLUSIONS The standardized visual assessment did not correlate well with ROTEM® measurements, suggesting that it is not useful to detect coagulopathy. Trial registry number: ClinicalTrials.gov identifier No. NCT01487837.
Hemostasis and Fibrinolysis following Aneurysmal Subarachnoid Hemorrhage: A Systematic Review on Additional Knowledge from Dynamic Assays and Potential Treatment Targets
Seminars in thrombosis and hemostasis. 2021
Mortality after aneurysmal subarachnoid hemorrhage (aSAH) is augmented by rebleeding and delayed cerebral ischemia (DCI). A range of assays evaluating the dynamic process of blood coagulation, from activation of clotting factors to fibrinolysis, has emerged and a comprehensive review of hemostasis and fibrinolysis following aSAH may reveal targets of treatment. We conducted a systematic review of existing literature assessing coagulation and fibrinolysis following aSAH, but prior to treatment. PubMed, Embase, and Web of Science were searched on November 18, 2020, without time boundaries. In total, 45 original studies were eventually incorporated into this systematic review, divided into studies presenting data only from conventional or quantitative assays (n = 22) and studies employing dynamic assays (n = 23). Data from conventional or quantitative assays indicated increased platelet activation, whereas dynamic assays detected platelet dysfunction possibly related to an increased risk of rebleeding. Secondary hemostasis was activated in conventional, quantitative, and dynamic assays and this was related to poor neurological outcome and mortality. Studies systematically investigating fibrinolysis were sparse. Measurements from conventional or quantitative assays, as well as dynamic fibrinolysis assays, revealed conflicting results with normal or increased lysis and changes were not associated with outcome. In conclusion, dynamic assays were able to detect reduced platelet function, not revealed by conventional or quantitative assays. Activation of secondary hemostasis was found in both dynamic and nondynamic assays, while changes in fibrinolysis were not convincingly demonstrable in either dynamic or conventional or quantitative assays. Hence, from a mechanistic point of view, desmopressin to prevent rebleeding and heparin to prevent DCI may hold potential as therapeutic options. As changes in fibrinolysis were not convincingly demonstrated and not related to outcome, the use of tranexamic acid prior to aneurysm closure is not supported by this review.