Performance Evaluation of a New Point of Care Viscoelastic Coagulation Monitoring System in Major Abdominal, Orthopaedic and Vascular Surgery

A Deployable Viscoelastic Coagulation Monitor Enables Point-of-Care Assessment of Coagulopathy in Swine With Polytrauma

INTRODUCTION

Absence of pre-hospital coagulation tests challenges prompt management of hemostasis after trauma. The Viscoelastic Coagulation Monitor (VCM, Entegrion, Durham, NC) is a hand-held coagulation test for point-of-care. We evaluated VCM in a translational swine polytrauma model, hypothesizing that VCM correlates with a laboratory reference method, the TEG 5000 (Haemonetics, Boston, MA), and can identify coagulopathic phenotypes relevant to trauma. Our secondary hypothesis was that pre-warming of VCM disposable test cartridges using a heating plate versus pre-warming of cartridges by carrying the cartridge in the user's pocket does not significantly alter results.

MATERIALS AND METHODS

This study was conducted in tandem with a parent study involving anesthetized, mechanically ventilated swine (n = 20; 54 ± 5 kg) that encountered traumatic brain injury, pulmonary contusion and hemorrhage, or combination/polytrauma injury. Blood was collected at baseline, post-injury, post-shock, post-transfusion, and 6-, 24-, and 48 h post-injury to perform VCM at point-of-care. Within-group effect of time was assessed. Spearman correlation examined linear relations between VCM and standard laboratory-based coagulation tests; as well as lactate, ionized calcium, and body temperature. Logistic regression examined predictiveness of VCM to identify coagulopathic phenotypes, with receiver operator characteristic curves generated to assess diagnostic capability. At a subset of timepoints, necessity of pre-warming the VCM test cartridge using a heating plate versus pre-warming the cartridge by placement in the user's pocket was assessed by conducting simultaneous tests on two separate instruments, with results analyzed by paired t-test with crossover design.

RESULTS

VCM revealed time-dependent changes in clotting time, clot formation time (CFT), alpha, maximum clot firmness (MCF), and lysis index (LI30). All VCM metrics correlated with the respective TEG 5000 metrics, with strongest correlation for VCM MCF with TEG MA (rhos = 0.77, P < .0001) and VCM LI30 with TEG LY30 (rhos = -0.76, P < .0001). VCM demonstrated good (area under the curve >0.70) to excellent (area under the curve >0.90) diagnostic accuracy in detection of low platelet count (MCF), low hematocrit (clotting time, clot formation time, alpha, and MCF), low fibrinogen (MCF), and high fibrinogen (alpha, MCF). There was no statistically or clinically relevant effect of cartridge warming method on results.

CONCLUSIONS

In a trauma model, VCM detected significant changes in coagulation at point-of-care in a simplified portable form factor. VCM could enable informed hemostasis management in pre-hospital settings where coagulations tests are unavailable, pending further validation in clinical trials.

In vitro evaluation of a new viscoelastometry-based point-of-care analyzer

INTRODUCTION

The VCM is a point-of-care analyzer using a new viscoelastometry technique for rapid assessment of hemostasis on fresh whole blood. Its characteristics would make it suitable for use in austere environments. The purpose of this study was to evaluate the VCM in terms of repeatability, reproducibility and interanalyzer correlation, reference values in our population, correlation with standard coagulation assays and platelet count, correlation with the TEG5000 analyzer and resistance to stress conditions mimicking an austere environment.

METHODS

Repeatability, reproducibility, and interanalyzer correlation were performed on quality control samples (n = 10). Reference values were determined from blood donor samples (n = 60). Correlations with standard biological assays were assessed from ICU patients (n = 30) and blood donors (n = 60) samples. Correlation with the TEG5000 was assessed from blood donor samples. Evaluation of vibration resistance was performed on blood donor (n = 5) and quality control (n = 5) samples.

RESULTS

The CVs for repeatability and reproducibility ranged from 0% to 11%. Interanalyzer correlation found correlation coefficients (r2) ranging from 0.927 to 0.997. Our reference values were consistent with those provided by the manufacturer. No robust correlation was found with conventional coagulation tests. The correlation with the TEG5000 was excellent with r2 ranging from 0.75 to 0.92. Resistance to stress conditions was excellent.

CONCLUSION

The VCM analyzer is a reliable, easy-to-use instrument that correlates well with the TEG5000. Despite some logistical constraints, the results suggest that it can be used in austere environments. Further studies are required before its implementation.

Comparison of a viscoelastic point-of-care coagulation monitor with thromboelastography in sick dogs with hemostatic abnormalities

BACKGROUND

Viscoelastic coagulation monitor (VCM-Vet) is a point-of-care device that has been used to characterize hemostatic abnormalities in sick pets but has not been validated in veterinary patients.

OBJECTIVES

We aimed to compare VCM-Vet and thromboelastography (TEG) in sick dogs with suspected disorders of hemostasis.

METHODS

Duplicate VCM-Vet tests using untreated native blood performed concurrently on two VCM-Vet machines, and simultaneous TEG tests were performed (one citrated native (CN), and one activated with tissue factor (TF) at a 1:3600 dilution). Each VCM-Vet result was compared with both TF-activated and CN TEG.

RESULTS

Fifty-three dogs were enrolled. Eleven cases displayed apparent hyperfibrinolysis. Spearman correlation coefficients for individual VCM-Vet devices and CN and TF TEG were obtained between R and CT values and ranged from 0.21 to 0.27, CFT and K (r = 0.60-0.67), angles (r = 0.51-0.62), and MCF and MA (r = 0.85-0.87). Comparison of the two VCM-Vet devices displayed positive correlations for all clot formation parameters with Lin's concordance correlation coefficients of 0.75-0.95. Variable lysis parameter agreement existed between the VCM-Vet devices and VCM-Vet and TEG. When samples were classified as hypercoagulable or coagulopathic, VCM-Vet had a low positive predictive value (17-33%) for the detection of hypercoagulable states and a moderate negative predictive value (64-74%) for the detection of coagulopathy as defined by TEG.

CONCLUSIONS

VCM-Vet and TEG had variable correlations in clot formation values and a strong correlation for final clot strength. More information is needed to make conclusions about the lysis parameters. Artifact in the fibrinolysis portion of the test can confound the interpretation of VCM-Vet results.

Evaluation of a Viscoelastic Coagulation Monitoring System (VCM Vet®) and Its Correlation with Thromboelastometry (ROTEM®) in Diseased and Healthy Dogs

Thromboelastometry provides a real-time assessment of global coagulation in whole blood. A novel bed-side viscoelastic coagulation monitor (VCM) has been developed for use in small animals. The aims of the study were to determine inter-device agreement of two VCM devices, to evaluate the correlation between VCM and rotational thromboelastometry as a reference method (ROTEM), and to determine the sensitivity and specificity of VCM to diagnose hypo-, normo-, and hypercoagulability. ROTEM (extrinsic and intrinsic activation) analysis was performed using citrated blood and VCM analysis using native blood. Twenty healthy and forty diseased dogs with and without coagulopathies were enrolled. The VCM inter-device agreement was moderate to strong for most of the parameters, depending on the grading scale. Correlation between VCM and ROTEM was moderate to strong for parameters of clotting time and clot strength. The VCM most likely detects true hypocoagulability and reliably rules out hypocoagulability. The VCM has a high sensitivity in diagnosing normocoagulability, but incorrectly classified dogs with abnormal coagulation as normocoagulable. The VCM was not able to detect hypercoagulability. ROTEM and VCM cannot be used interchangeably.

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.

Viscoelastic Hemostatic Assays for Orthopedic Trauma and Elective Procedures

The application of viscoelastic hemostatic assays (VHAs) (e.g., thromboelastography (TEG) and rotational thromboelastometry (ROTEM)) in orthopedics is in its relative infancy when compared with other surgical fields. Fortunately, several recent studies describe the emerging use of VHAs to quickly and reliably analyze the real-time coagulation and fibrinolytic status in both orthopedic trauma and elective orthopedic surgery. Trauma-induced coagulopathy—a spectrum of abnormal coagulation phenotypes including clotting factor depletion, inadequate thrombin generation, platelet dysfunction, and dysregulated fibrinolysis—remains a potentially fatal complication in severely injured and/or hemorrhaging patients whose timely diagnosis and management are aided by the use of VHAs. Furthermore, VHAs are an invaluable compliment to common coagulation tests by facilitating the detection of hypercoagulable states commonly associated with orthopedic injury and postoperative status. The use of VHAs to identify hypercoagulability allows for an accurate venous thromboembolism (VTE) risk assessment and monitoring of VTE prophylaxis. Until now, the data have been insufficient to permit an individualized approach with regard to dosing and duration for VTE thromboprophylaxis. By incorporating VHAs into routine practice, orthopedic surgeons will be better equipped to diagnose and treat the complete spectrum of coagulation abnormalities faced by orthopedic patients. This work serves as an educational primer and up-to-date review of the current literature on the use of VHAs in orthopedic surgery.

The Non-Activated Thromboelastometry (NATEM) Assay's Application among Adults and Neonatal/Pediatric Population: A Systematic Review

The non-activated thromboelastometry (NATEM) assay is a point-of-care assay that can provide a comprehensive insight into the actual hemostatic mechanism. However, there are very limited data about its use in clinical practice. The aim of this study was to systematically review the literature for any data regarding the use of NATEM in several clinical settings. A systematic review of PubMed and Scopus databases was conducted through 20 January 2022 for studies evaluating the use of the NATEM assay in different clinical settings. The literature search yielded a total of 47 publications, 30 of which met the eligibility criteria for this review. Evaluation of NATEM’s detecting ability for hemostasis disorders is limited in the literature. The results of the included studies indicate that NATEM seems to be a sensitive method for the detection of hyperfibrinolysis and may have an advantage in the diagnosis of hemostatic disorders. It could be more informative than the other ROTEM assays for detecting changes in coagulation parameters in patients who receive anticoagulants. However, the reported outcomes are highly varying among the included studies. NATEM has a high sensitivity to detect hypo- or hypercoagulability and provides a detailed insight into the whole hemostatic process from clot formation to clot breakdown. It could be a useful technique in variable fields of medicine, not only in adults, but also in pediatric and neonatal populations, to guide different hemostatic treatments and predict coagulation disorders or mortality/morbidity; this issue remains to be further investigated.

Response of the VCMVet viscoelastic coagulation monitor to veterinary environmental simulation challenges

BACKGROUND

Traditional viscoelastic clotting tests are significantly impacted by the operator and environmental variation. The VCMVet coagulation monitor could provide a more user-friendly alternative for veterinary practices.

OBJECTIVES

We aimed to determine if environmental vibration commonly encountered in veterinary practice alters the results of a point-of-care viscoelastic device, the VCMVet.

METHODS

Nine fresh whole blood samples from healthy dogs were evaluated simultaneously using VCMVet instruments under four environmental conditions: (normal) alone and undisturbed on a raised tabletop, (centrifuge) on a countertop 6 inches from a centrifuge that operated at 12 000 rpm for 10 minutes every 20 minutes, (workspace) on a tabletop workspace in proximity to two heavy-use computers, and (gurney) on a rolling gurney at a walking pace for 10 minutes every 20 minutes. Results were compared between conditions using a Friedman test, and if this was significant (P-value < .05), it was followed by a Wilcoxon test for paired samples.

RESULTS

Analysis of samples on a rolling gurney created obvious movement artifacts, and this condition was excluded from statistical analysis. The centrifuge condition resulted in a significantly higher alpha angle (median 49 degrees, interquartile range 4) than the normal condition (median 46 degrees, interquartile range 5, P = .0078). Other viscoelastic parameters were not significantly different between the normal, centrifuge, and workspace conditions.

CONCLUSIONS

The VCMVet is suitable for use in a busy veterinary environment but should be protected from vibration. The instrument does not produce reliable results when operated on a moving gurney, and it should be stationary during sample analysis.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

Agreement Between the TEG 6s and TEG 5000 Analyzers in Extracorporeal Membrane Oxygenation

Thromboelastography (TEG) evaluates viscoelastic properties of blood clot formation. The TEG 5000 analyzer is commonly used but prone to errors related to vibration or operator error. The TEG 6s was developed to overcome these limitations. Performance of TEG 6s compared with TEG 5000 has not been reported in extracorporeal membrane oxygenation (ECMO). We compared the agreement between devices via a single-center prospective observational study in hospitalized adult patients on ECMO. Data for both devices were collected daily for 3 days after ECMO initiation. Standard tests for method comparison were used. Thirty-four matching samples were available for analysis. Minimal bias was noted; however, the limit of agreement was wide for TEG parameters. Visually, agreement was better for values within the reference ranges of the tests. Lin's coefficients demonstrated moderate correlation for reaction time and alpha angle (0.58; 95% confidence interval [CI], 0.31-0.76 and 0.63; 95% CI, 0.40-0.78, respectively). Excellent correlation was demonstrated for kinetic time and maximum amplitude (0.88; 95% CI, 0.79-0.94 and 0.89; 95% CI, 0.79-0.94). The TEG 6s device may represent an acceptable surrogate for the TEG 5000 in patients on ECMO. However, limitations in reliability were noted, and the devices may not be interchangeable when results fall outside of the reference values.

Individualized Bleeding Risk Assessment through Thromboelastography: A Case Report of May-Hegglin Anomaly in Preterm Twin Neonates

May–Hegglin anomaly (MHA) is a rare autosomal dominant disorder in the spectrum of myosin heavy chain-related disorders (MYH9-RD), characterized by congenital macrothrombocytopenia and white blood cell inclusions. MHA carries a potential risk of hemorrhagic complications. Bleeding diathesis is usually mild, but sporadic, life-threatening events have been reported. Data regarding the clinical course and outcomes of neonatal MYH9-RD are limited, and specific guidelines on platelet transfusion in asymptomatic patients are lacking. We present monochorionic twins born preterm at 32 weeks of gestation to an MHA mother; both presented with severe thrombocytopenia at birth. Peripheral blood smear demonstrated the presence of macrothrombocytes, and immunofluorescence confirmed the diagnosis of MHA. Close clinical monitoring excluded bleeding complications, and serial hemostatic assessments through a viscoelastic system demonstrated functionally normal primary hemostasis in both patients. Therefore, prophylactic platelet transfusions were avoided. Whole DNA sequencing confirmed the pathogenetic variant of MHA of maternal origin in both twins. Thromboelastography allowed real-time bedside bleeding risk assessment and supported individualized transfusion management in preterm newborns at risk of hemostatic impairment. This report suggests that dynamic and appropriate clotting monitoring may contribute to the more rational use of platelets’ transfusions while preserving patients with hemorrhagic complications and potential transfusion-related side effects.

Impact of blood sampling technique on reproducibility of viscoelastic coagulation monitor (VCM™) system test results in the neonate

Purpose: To evaluate the reproducibility of the results of the viscoelastic coagulation test (VCT) performed with a new viscoelastic coagulation monitor (VCM™ - Entegrion) on native blood obtained by heel prick blood sampling with two different techniques compared to the standard blood collection in the newborn.Methods: Three blood samples were tested with the VCM analyzer in each of the 67 study subjects admitted to our level 3 neonatal intensive care unit. Standard blood collection (S) was performed by direct puncture of a peripheral vessel or by drawing of blood in a syringe connected to an arterial or venous catheter. Then, two more blood samples were drawn through a single heel prick. The first heel prick blood sample (HP1) was collected in the sample well through the attached metal capillary while the second (HP2) was poured directly into the sample well. Blood samples were automatically drawn into their pre-warmed cartridges and inserted into the VCM analyzers set up for analyses, which ran for one hour. VCT blood variables included clotting time (CT), clot formation time (CFT), angle alpha (α), amplitude at 10 and 20 min (A10 and A20), maximum clot firmness (MCF), and lysis indexes at 30 and 45 min (LY30 - LY45). Agreement was quantified by calculating the mean difference and SD between measurements of VCT blood variables from S, HP1 and HP2 blood samples. The 95% limits of agreement were calculated by the Bland & Altman method, using the upper or lower limit of agreement to interpret the variability of the measurements. The Kendall's τ correlation coefficient evaluated the interdependence between SD and intra-measurement mean.Results: S blood samples were easily obtained in all the study subjects, while mild difficulties were recorded in 3/67 infants (4.5%) with the HP1 blood sampling and in 5/67 infants (7%) with the HP2 blood sampling. Pairwise comparison of test results performed on blood samples drawn with HP1 and HP2 techniques showed moderate agreement for CT and α-angle, strong agreement for CFT, LY30 and LY45 and almost perfect agreement for A10, A20 and MCF. In pairwise comparison of VCM analyses performed on blood samples drawn with S technique vs HP1 and HP2 techniques, Kendall's τ correlation coefficient was significant for CT (S vs HP1 and HP1 vs HP2), CFT (S vs HP1 and S vs HP2), α-angle (S vs HP1) and MCF (S vs HP1). This suggests that the measurement error depends on the extent of the measurement. The overall ICC for blood sampling techniques ranged from 0.289 to 0.879 with best agreement observed for CFT (strong) and for A10, A20 and MCF (almost perfect). The LY30 index was the least repeatable measurement (poor agreement). The VCM analysis performed on the blood sample drawn with the HP1 technique showed the best repeatability compared with that performed with the S blood-sampling technique.Conclusion. VCT test results performed with the VCM analyzer on native blood drawn by heel prick in neonates are comparable to those obtained from standard blood samples. This could allow for a widespread, real-time assessment of the overall bedside haemostasis of these small patients.

Viscoelastic Coagulation Monitor (VCMVet) Reference Intervals and Sex Differences in Mature Adult Mice

INTRODUCTION

Viscoelastic coagulation tests are useful to assess coagulation status in the clinical setting and to aid in understanding underlying pathophysiological mechanisms that affect coagulation status. Such tests also are useful for coagulation research. Because mouse models are widely used to study molecular mechanisms in fine detail, a simple viscoelastic coagulation test requiring small blood volumes would be convenient for such studies in mice.

METHODS

We tested viscoelastic coagulation properties of normal healthy adult mice using a novel veterinary clinical point-of-care device, Viscoelastic Coagulation Monitor (VCM Vet™; Entegrion Corp.). Fresh whole blood was collected from 63 healthy mature adult C57 black 6N mice, with ultimately 54 mice, equal numbers of male and females, used to determine reference intervals (RIs) for VCM test parameters.

RESULTS

RIs were determined for equal numbers of male and female mice: clot time: 43.0-353.0 s; clot formation time: 49.4-137.6 s; alpha angle: 54.4-62.2°; A10: 25.0-49.6 VCM units; A20: 31.0-56.5 VCM units; maximum clot firmness: 37.6-62.8 VCM units; Lysis Index 30 (Li30): 99.8-100.0%; and Li45: 99.7-100.0%. Significant differences were found between male and female subgroups, where females had higher mean A10 and A20 and median MCF values, indicating greater clot firmness in female versus male mice.

CONCLUSION

VCM Vet is a feasible viscoelastic coagulation test device for studies with mature adult mice, including studying inherent sex differences in coagulation parameters. Inherent differences in coagulability of male and female mice warrant further investigation to determine if such differences underlie greater coagulopathic, hemorrhagic, or thromboembolic risk during trauma or other pathophysiologic conditions.

Comparison of viscoelastic test results from blood collected near simultaneously from the jugular and saphenous veins in cats

OBJECTIVES

The aim of this study was to compare viscoelastic test results from samples collected from a jugular vein using a 20 G needle and a medial saphenous vein using a 22 G needle in cats presenting for elective ovariohysterectomy (OHE) or castration.

METHODS

Forty apparently healthy cats (20 males and 20 females) presenting for elective OHE or castration were included in a prospective study observing viscoelastic test results from central and peripherally collected whole blood. Cats were anesthetized during blood collection with a standardized protocol including buprenorphine, ketamine, dexmedetomidine and isoflurane. Blood samples from jugular and saphenous veins were collected near simultaneously. Viscoelastic evaluations of whole blood were performed using a point-of-care device measuring clot time (CT), clot formation time (CFT), alpha angle (α), maximum clot formation (MCF), and amplitude at 10 and 20 mins (A10 and A20, respectively). Viscoelastometry continued post-clot time to determine a lysis index at 30 and 45 mins (LI30 and LI45, respectively) to assess fibrinolysis.

RESULTS

Studied cats had a median age of 18 months (range 5 months to 5 years) and a median weight of 3.6 kg (range 2.7-5.9 kg). A total of 80 samples were available for analysis. While lysis indices were not different, viscoelastic measures of coagulation differed between sampling sites (CT, P <0.005; CFT, P = 0.01; α, P <0.05; MCF, P <0.0005; A10, P <0.0005; A20, P <0.0005).

CONCLUSIONS AND RELEVANCE

Viscoelastic results from jugular venous blood samples appear to be more hypercoagulable than those collected from the medial saphenous vein, suggesting that the same site should be used consistently for serial monitoring or for collecting study data.

Viscoelastic Coagulation Monitor as a Novel Device to Assess Coagulation at the Bedside. A Single-Center Experience During the COVID-19 Pandemic

Viscoelastic coagulation monitor (VCM) is a portable device developed to evaluate the viscoelastic properties of whole blood activated by contact with glass. In this study, VCM was employed to analyze the viscoelastic profiles of 36 COVID-19 intensive care patients. Full anticoagulant dose heparin (unfractionated [UFH]; low molecular weight [LMWH]) was administrated to all patients. The association between VCM and laboratory parameters was retrospectively analyzed. The administration of UFH-influenced VCM parameters prolonging clotting time (CT) and clot formation time (CFT) and reducing angle (alpha) and amplitudes of the VCM tracings (A10, A20, and maximum clot firmness [MCF]) compared with LMWH therapy. A tendency toward hypercoagulation was observed by short CT and CFT in patients receiving LMWH. Clotting time was correlated with UFH dose (Spearman's rho = 0.48, p ≤ 0.001), and no correlation was found between CT and LMWH. All VCM tracings failed to show lysis at 30 and 45 minutes, indicating the absence of fibrinolysis. A10, A20, and MCF exhibited very-good to good diagnostic accuracy for detecting platelet count and fibrinogen above the upper reference limit of the laboratory. In conclusion, VCM provided reliable results in COVID-19 patients and was easy to perform with minimal training at the bedside.

Association of D-dimer and Fibrinogen With Hypercoagulability in COVID-19 Requiring Extracorporeal Membrane Oxygenation

BACKGROUND

D-dimer concentration has been used by institutions to identify candidates for intensified anticoagulant treatment for venous thromboembolism prevention and for the mitigation of the microthrombotic complications associated with COVID-19. Thromboelastography (TEG) maximum amplitude (MA) has been validated as a marker of hypercoagulability and MA ≥68 mm has been utilized as a marker of hypercoagulability in other conditions.

METHODS

The goal of this study was to evaluate the relationship between coagulation, inflammatory, and TEG parameters in patients with COVID-19 on extracorporeal membrane oxygenation (ECMO). We performed a single-center retrospective analysis of consecutive patients that received ECMO for the treatment of COVID-19. TEG, inflammatory, and coagulation markers were compared in patients with and without a thrombotic complication. Correlation tests were performed to identify the coagulation and inflammatory markers that best predict hypercoagulability as defined by an elevated TEG MA.

RESULTS

A total of 168 TEGs were available in 24 patients. C-reactive protein and fibrinogen were significantly higher in patients that developed a thrombotic event versus those that did not (P = 0.04 and P = 0.04 respectively). D-dimer was negatively correlated with TEG MA (P < 0.01), while fibrinogen was positively correlated (P < 0.01). A fibrinogen >441 mg/dL was found to have a sensitivity of 91.2% and specificity of 85.7% for the detection of MA ≥68 mm.

CONCLUSIONS

In critically ill patients with COVID-19 treated with ECMO, D-dimer concentration had an inverse relationship with degree of hypercoagulability as measured by TEG MA. D-dimer elevation may potentially reflect hemostatic perturbation in patients on ECMO or the severity of COVID-19 related sepsis rather than designate patients likely to benefit from anticoagulation. Fibrinogen concentration may represent a more useful marker of hypercoagulability in this population.