Thromboelastography: a review for radiologists and implications on periprocedural bleeding risk.

Thromboelastography (TEG) and rotational thromboelastometry are emerging technologies that are gaining increasing acceptance in the medical field to evaluate the coagulation status of patients on an individual level by assessing dynamic clot formation. TEG has been proven to reduce blood product use as well as improve patient outcomes in a variety of medical settings, including trauma and surgery due to the expediated nature of the test as well as the ability to determine specific deficiencies present in whole blood that are otherwise undetectable with traditional coagulation studies. Currently, no guidelines or recommendations are in place for the utilization of TEG in interventional or diagnostic radiology although access to TEG has become increasingly common in recent years. This manuscript presents a review of prior literature on the technical aspects of TEG as well as its use in various fields and explains the normal TEG-tracing parameters. Common hemodynamic abnormalities and their effect on the TEG tracing are illustrated, and the appropriate treatments for each abnormality are briefly mentioned. TEG has the potential to be a useful tool for determining the hemodynamic state of patients in both interventional and diagnostic radiology, and further research is needed to determine the value of these tests in the periprocedural setting.

Coagulopathy as a Surrogate of Severity of Injury in Penetrating Brain Injury.

Penetrating brain injury (PBI) is the most devastating type of traumatic brain injury. Development of coagulopathy in the acute setting of PBI, though common, remains of unclear significance as does its reversal. The aim of this study is to investigate the relationship between coagulopathy and clinical presentation, radiographical features, and outcome in civilian patients with PBI. Eighty-nine adult patients with PBI at a Level I trauma center in Chicago, Illinois who survived acute resuscitation and with available coagulation profile were analyzed. Coagulopathy was defined as international normalized ratio [INR] >1.3, platelet count <100,000 /µL, or partial thromboplastin time >37 sec. Median age (interquartile range; IQR) of our cohort was 27 (21-35) years, and 74 (83%) were male. The intent was assault in 74 cases (83%). The mechanism of PBI was gunshot wound in all patients. Forty patients (45%) were coagulopathic at presentation. In a multiple regression model, coagulopathy was associated with lower Glasgow Coma Scale (GCS)-Motor score (odds ratio [OR], 0.67; confidence interval [CI], 0.48-0.94; p = 0.02) and transfusion of blood products (OR, 3.91; CI, 1.2-12.5; p = 0.02). Effacement of basal cisterns was the only significant radiographical features associated with coagulopathy (OR, 3.34; CI, 1.08-10.37; p = 0.04). Mortality was found to be significantly more common in coagulopathic patients (73% vs. 25%; p < 0.001). However, in our limited sample, reversal of coagulopathy at 24 h was not associated with a statistically significant improvement in outcome. The triad of coagulopathy, low post-resuscitation GCS, and radiographical effacement of basal cisterns identify a particularly ominous phenotype of PBI. The role, and potential reversal of, coagulopathy in this group warrants further investigation.

Rapid thrombelastography predicts perioperative massive blood transfusion in patients undergoing coronary artery bypass grafting: A retrospective study.

Massive blood transfusion (MBT) is a relatively common complication of cardiac surgery, which is independently associated with severe postoperative adverse events. However, the value of using rapid thrombotomography (r-TEG) to predict MBT in perioperative period of cardiac surgery has not been explored. This study aimed to identify the effect of r-TEG in predicting MBT for patients undergoing coronary artery bypass grafting (CABG).This retrospective study included consecutive patients first time undergoing CABG at the Zhongnan Hospital of Wuhan University between March 2015 and November 2017. All the patients had done r-TEG tests before surgery. The MBT was defined as receiving at least 4 units of red blood cells intra-operatively and 5 units postoperatively (1 unit red blood cells from 200 mL whole blood).Lower preoperative hemoglobin level (P = .001) and longer cardiopulmonary bypass time (P = .001) were the independent risk factors for MBT during surgery, and no components of the r-TEG predicted MBT during surgery. Meanwhile, longer activated clotting time (P < .001), less autologous blood transfusion (P = .001), and older age (P = .008) were the independent risk factors for MBT within 24 hours of surgery.Preoperative r-TEG activated clotting time can predict the increase of postoperative MBT in patients undergoing CABG. We recommend the careful monitoring of coagulation system with r-TEG, which allows rapid diagnosis of coagulation abnormalities even before the start of surgery.

Mannose-Binding Lectin is Associated with Thrombosis and Coagulopathy in Critically Ill COVID-19 Patients.

The ongoing COVID-19 pandemic has caused significant morbidity and mortality worldwide, as well as profound effects on society. COVID-19 patients have an increased risk of thromboembolic (TE) complications, which develop despite pharmacological thromboprophylaxis. The mechanism behind COVID-19-associated coagulopathy remains unclear. Mannose-binding lectin (MBL), a pattern recognition molecule that initiates the lectin pathway of complement activation, has been suggested as a potential amplifier of blood coagulation during thromboinflammation. Here we describe data from a cohort of critically ill COVID-19 patients (n = 65) treated at a tertiary hospital center intensive care unit (ICU). A subset of patients had strongly elevated MBL plasma levels, and activity upon ICU admission, and patients who developed symptomatic TE (14%) had significantly higher MBL levels than patients without TE. MBL was strongly correlated to plasma D-dimer levels, a marker of COVID-19 coagulopathy, but showed no relationship to degree of inflammation or other organ dysfunction. In conclusion, we have identified complement activation through the MBL pathway as a novel amplification mechanism that contributes to pathological thrombosis in critically ill COVID-19 patients. Pharmacological targeting of the MBL pathway could be a novel treatment option for thrombosis in COVID-19. Laboratory testing of MBL levels could be of value for identifying COVID-19 patients at risk for TE events.

Case report of amniotic fluid embolism coagulopathy following abortion; use of viscoelastic point-of-care analysis.

BACKGROUND: Amniotic fluid embolism (AFE) is a rare, life threatening obstetric complication, often associated with severe coagulopathy. Induced abortions are extremely safe procedures however complications including AFE can occur. CASE PRESENTATION: A 29-year-old previously healthy woman, gravida 1 para 0, presented for a scheduled second trimester induced abortion via dilation and evacuation at 22-weeks gestation. The case was complicated by a suspected AFE with associated profound coagulopathy. Viscoelastic point-of-care coagulation analysis was used to successfully and swiftly guide management of her coagulopathy. CONCLUSION: AFE can occur in the setting of induced abortion. This case report suggests viscoelastic point-of-care coagulation analyzers may aid in the management of pregnancy-related coagulopathy by providing faster coagulation assessment than laboratory testing, and facilitating timely, targeted management of coagulopathy.

Correlation between hyperhemoglobinemia and pseudosubarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) is a severe cerebrovascular condition. Some cases present with typical signs of SAH on head computed tomography (CT), whereas other cases have a condition known as pseudo-SAH, with no bleeding actually present. In our clinical experience, we noted that cases of hyperhemoglobinemia often also had pseudo-SAH. Here we investigated the relationship between hyperhemoglobinemia and pseudo-SAH and explored the underlying mechanism. METHODS: We retrospectively collected data for patients who were treated for hyperhemoglobinemia in our hospital and had available brain CT scans. An age-matched control group of patients with normal hemoglobin levels was used to compare the incidence of pseudo-SAH between individuals with elevated versus normal hemoglobin levels. Spearman correlation and logistic regression analyses were performed to identify correlations between pseudo-SAH and hemoglobin level as well as gender, history of chronic obstructive pulmonary disease, and smoking history. RESULTS: The incidence of pseudo-SAH was significantly higher in hyperhemoglobinemia group than in the control group (12.5% vs. 1.6%, respectively, P < 0.001), and within the hyperhemoglobinemia group, it was significantly higher among those with a hemoglobin value ≥210 g/L than among those with a hemoglobin value <210 g/L (29.2% vs. 8.8%, respectively, P < 0.001). Spearman correlation analysis and logistic regression analysis showed a significant correlation between pseudo-SAH and hyperhemoglobinemia but no significant correlation between pseudo-SAH and gender, COPD, or smoking history. CONCLUSION: Hyperhemoglobinemia may be a contributing factor to pseudo-SAH. Clinicians should be aware of this phenomenon and be careful to distinguish pseudo-SAH from SAH, particularly in patients with hyperhemoglobinemia.

Coagulopathic hemorrhage with use of synthetic cannabinoids.

Synthetic cannabinoids contain many different chemicals and compounds, which pose new health risks to the population using these drugs. In May of 2018 the Center for Disease Control issued a health alert providing information on a multistate outbreak of coagulopathy from exposure to synthetic cannabinoid products containing a Vitamin K-dependent antagonistic agent such as brodifacoum. Recognizing signs, symptoms and imaging findings related to this outbreak is essential for clinicians caring for patients with a history or suspicion of using synthetic cannabinoids. To our knowledge, there are no studies that report the imaging findings demonstrating the coagulopathic complications associated with these synthetic compounds.

Prediction of venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging.

BACKGROUND: Venous malformations may be complicated by localized intravascular coagulopathy which is a serious condition with hematological sequel. Prediction of localized intravascular coagulopathy is mandatory for prompt anticoagulation therapy. Laboratory and routine magnetic resonance imaging can predict localized intravascular coagulopathy in venous malformations; however, the results are variable. PURPOSE: To predict venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging. MATERIAL AND METHODS: A retrospective analysis was performed on 55 patients (34 male, 21 female aged 14-64 years: mean 39 years) with venous malformations that underwent diffusion-weighted magnetic resonance imaging. The apparent diffusion coefficient value of venous malformations was calculated. RESULTS: The mean apparent diffusion coefficient value of venous malformations with localized intravascular coagulopathy (n = 26) (1.28 ± 0.18 × 10-3 mm2/s) was significantly different ( P = 0.001) from venous malformations without localized intravascular coagulopathy (n = 29) (1.60 ± 0.18 × 10-3 mm2/s). When apparent diffusion coefficient value of 1.454 × 10-3 mm2/s was used as a threshold value for the prediction of venous malformations with localized intravascular coagulopathy, the best result was obtained with an accuracy of 83.6%, sensitivity of 84.6%, specificity of 82.8%, and area under the curve of 0.895. The apparent diffusion coefficient value of venous malformations was correlated with D-dimer level ( r = -0.59, P = 0.006) and fibrinogen level ( r = 0.73, P = 0.001). CONCLUSION: The apparent diffusion coefficient value is a non-invasive imaging parameter that can be used to predict venous malformations with localized intravascular coagulopathy.

Brodifacoum-contaminated synthetic marijuana: clinical and radiologic manifestations of a public health outbreak causing life-threatening coagulopathy.

Synthetic marijuana is a dangerous substance due to its potency, ever-changing composition, and unpredictable side effects. Recently, brodifacoum-contaminated synthetic marijuana has led to multiple deaths and morbidity throughout the USA from severe coagulopathy associated with use of this strain of the drug (brodifacoum is a rodenticide and potent Vitamin K antagonist/anticoagulant). We describe the clinical and radiologic findings in two patients who were diagnosed with, and treated for, ingestion of this new strain of synthetic marijuana. The radiologic manifestations were most notable for hemorrhagic pyelitis/ureteritis. Both patients required hospitalization with Vitamin K supplementation. The radiologic and clinical pictures in these patients are important for radiologists to recognize in order to help guide appropriate patient management.

Clot dynamics and mortality: The MA-R ratio.

INTRODUCTION: The coagulopathy of trauma, illustrated by a short R-time, is common and well understood. The physiology behind this may be early thrombin burst with rapid clot formation. Rapid consumption of fibrinogen, however, may result in weak clot and substrate depletion, resulting in low MA. While these characteristics are interesting, utilizing thromboelastography (TEG) to identify those at risk of subsequent bleeding diathesis, especially in those who do not demonstrate early signs of physiologic derangement, is challenging. We have developed a novel ratio utilizing TEG values to describe patients at specific risk of traumatic coagulopathy. The purpose of this study was to create a single TEG value, which would reflect both the hypercoagulability and hypocoagulability of TIC. We hypothesized that this ratio, at admission, would be indicative of TIC and predictive of both blood product transfusion volumes and subsequent mortality. METHODS: Patients admitted via the highest activation criteria at one of two Level I trauma centers were included if they received at least 1 unit of packed red blood cells in the first 24 hours of admission. The admission TEG was collected, and a ratio was calculated by dividing the MA by the R-time (MA-R). MA-R quartiles were developed, and multivariable logistic regression was utilized to determine odds of mortality. RESULTS: Three hundred thirty patients with admission TEG were included. In all patients, median age was 35 years (interquartile range, 25-54 years), Injury Severity Score (ISS) was 20 (interquartile range, 13-29), 76% were male, and 43% had penetrating trauma. The MA-R groups were based on quartiles. Multivariable analysis, controlling for mechanism of injury, ISS, and admission pH, showed that increasing ratios were associated with decreased odds of death. The lowest MA-R ratios were also significantly associated with higher ISS, higher rates of blunt injury, and higher plasma utilization without a significant difference in packed red blood cell administration. CONCLUSIONS: Patients with the lowest MA-R ratios demonstrated the highest mortality rates. This novel ratio may prove highly useful to predict at-risk patients early, when other physiologic indicators are absent. The mechanism driving this finding may rest in fibrinogen depletion, resulting in weak clot. Patients with low MA-R ratios may benefit from earlier resuscitation with cryoprecipitate, rather than the traditional use of plasma found in current massive transfusion protocols. LEVELS OF EVIDENCE: Prognostic study, Level I.

Who Orders a Head CT?: Perceptions of the Cirrhotic Bleeding Risk in an International, Multispecialty Survey Study.

OBJECTIVE: Traditional coagulopathic indices, including elevated international normalized ratio, do not correlate with bleeding risk in patients with cirrhosis. For this reason, head computed tomography (CT) has a low yield in cirrhotic patients with altered mental status and no trauma history. The initial diagnostic evaluation, however, is often made by nongastroenterologists influenced by the so-called "coagulopathy of cirrhosis." We sought to examine the prevalence, impact, and malleability of this perception in an international, multispecialty cohort. DESIGN: An electronic survey was distributed to internal medicine, surgery, emergency medicine, and gastroenterology physicians. Respondents were presented with a cirrhotic patient with hepatic encephalopathy, no history of trauma, and a nonfocal neurological examination. Respondents rated likelihood to order head CT at presentation, after obtaining labs [international normalized ratio (INR) 2.4 and platelets 59×10/µL], and finally after reading the results of a study demonstrating the low yield of head CT in this setting. RESULTS: In total, 1286 physicians from 6 countries, 84% from the United States. Of these, 62% were from internal medicine, 25% from emergency medicine, 8% from gastroenterology, and 5% from surgery. Totally, 47% of respondents were attending physicians. At each timepoint, emergency physicians were more likely, and gastroenterologists less likely, to scan than all other specialties (P<0.0001). Evidence on the low yield of head CT reduced likelihood to scan for all specialties. Qualitative analysis of open-ended comments confirmed that concern for "coagulopathy of cirrhosis" motivated CT orders. CONCLUSIONS: Perceptions regarding the coagulopathy of cirrhosis, which vary across specialties, impact clinical decision-making. Exposure to clinical evidence has the potential to change practice patterns.

Central Nervous System Complications of Hemorrhagic and Coagulation Disorders.

Hematologic disorders affect the central nervous system in a variety of ways, producing a wide range of neurologic disturbances. Early identification of these complications allows for early intervention and better outcome. Cross-sectional imaging plays an important role in identifying brain abnormalities and helps the clinician in deciding appropriate course of action and treatment. This article discuss in short the basics of hemostasis including the coagulation cascade and the application of basic laboratory tests in evaluation of hematologic function. Imaging features of various neurologic disorders associated with these clotting and bleeding diatheses are discussed in detail with illustrations.

Ultrasound-guided left brachiocephalic vein cannulation in children with underlying bleeding disorders: a retrospective analysis.

OBJECTIVES: To evaluate the safety and effectiveness of ultrasound-guided left brachiocephalic vein cannulation in infants and children with underlying bleeding conditions. DESIGN: Retrospective cohort. SETTING: PICU of a tertiary pediatric hospital. PATIENTS: Thirty-four patients requiring central venous catheterization from January 2011 to January 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two pediatric intensivists, experienced in ultrasound-guided vessel cannulation, performed the ultrasound catheterization of the left brachiocephalic vein. Ultrasound equipment consisted of a standard ultrasound monitor with a linear 6-13 MHz probe. The ultrasound monitor was set on a resolution with a depth of 1.8 cm for infants and 2.2 cm for children. The "in-plane" technique was used for all patients. Thirty-four catheterizations were performed. Patient median age was 12.5 months (5.75-63.5 mo) and median weight was 9.25 kg (7-16.25 kg). The population of infants and children analyzed was composed of 25 patients with hematologic disorder (73%) treated with hematopoietic stem cell transplantation, five patients (15%) supported with extracorporeal membrane oxygenation for viral pneumonias, and four patients (12%) with uremic hemolytic syndrome. A 4F catheter was used in 79% of cases. Left brachiocephalic vein cannulation was successful in all 34 patients. Median time needed for cannulation was 350 seconds (277.5-450 s). The overall complication rate was 9% (3 of 34) and consisted of difficulty in advancing the guidewire after having pierced the vein. The time required for catheter positioning and complications was not associated with both lower body weight and body surface area of the patients (p > 0.05). Mean central venous catheter duration was 32 ± 4 days. CONCLUSIONS: Data reported in this retrospective study confirm the safety and effectiveness of ultrasound-guided left brachiocephalic vein catheterization in infants and children with underlying bleeding disorders.

The influence of hemocoagulation disorders on the development of posttraumatic cerebral infarction and outcome in patients with moderate or severe head trauma.

Posttraumatic cerebral infarction (PTCI) is a severe secondary insult of head injury and often leads to a poor prognosis. Hemocoagulation disorder is recognized to have important effects on hemorrhagic or ischemic damages. We sought to assess if posttraumatic hemocoagulation disorders were associated with cerebral infarction, and evaluate their influence on outcome among patients with moderate or severe head trauma. In this study, PTCI was observed in 28 (10.57%) of the 265 patients within the first week after injury. In multivariate analysis, the thrombocytopenia (odds ratio (OR) 2.210, 95% confidence interval (CI) 1.065-4.674), abnormal prothrombin time (PT) (OR 3.241, 95% CI 1.090-7.648), D-dimer (>2 mg/L) (OR 7.260, 95% CI 1.822-28.076), or disseminated intravascular coagulation (DIC) scores (≥ 5) (OR 4.717, 95% CI 1.778-12.517) were each independently associated with an increased risk of PTCI. Admission Glasgow Coma Scale (GCS) score, abnormal activated partial thromboplastin time (APTT) and fibrinogen, and D-dimer (>2 mg/L) and DIC scores (≥ 5) showed an independent predictive effect on poor outcome. In conclusion, recognition of this important treatable cause of PTCI and the associated risk factors may help identify the group at risk and tailor management of patients with TBI.

Haemostatic and cranial computed tomography characteristics in patients with acute and delayed coagulopathy after isolated traumatic brain injury.

PRIMARY OBJECTIVE: To investigate whether the development of coagulopathy at different stages after isolated traumatic brain injury (TBI) is associated with distinct cranial computed tomography characteristics. RESEARCH DESIGN: Retrospective cohort study in 226 patients with moderate-to-severe isolated TBI who were categorized as subjects without coagulopathy or with acute temporary, acute sustained or delayed coagulopathy. METHODS AND PROCEDURES: Coagulopathy was defined as an activated partial thromboplastin time >40 seconds and/or prothrombin time (PT) >1.2 and/or platelet count <120*10(9)l(-1). Cranial CT scans were assigned to the six-point Traumatic Coma Data Bank (TCDB) CT-classification. MAIN OUTCOMES AND RESULTS: Coagulopathy occurred in 44% of patients in the first 24-hours post-trauma. Patients with acute, sustained coagulopathy showed a prolonged PT (1.64 ± 0.89) when compared to patients without (1.03 ± 0.07), acute temporary (1.27 ± 0.22) or delayed coagulopathy (1.08 ± 0.06; p < 0.05). Patients with acute temporary or delayed coagulopathy had the worst TCDB CT classification scores, while mortality rates were the highest in patients with sustained or delayed coagulopathy. CONCLUSIONS: Not only the mere presence of coagulopathy, but also the course of haemostatic alterations following neurotrauma may hold predictive value for patient outcome, irrespective of the severity level of cerebral injury.

A review of current methods for assessing hemostasis in vivo and introduction to a potential alternative approach.

A validated method for assessing hemostasis in vivo is critical for testing the hemostatic efficacy of therapeutic agents in preclinical animal models and in patients with inherited bleeding disorders, such as von Willebrand disease (VWD) and hemophilia A, or with acquired bleeding disorders such as those resulting from medications or disease processes. In this review, we discuss current methods for assessing hemostasis in vivo and the associated challenges. We also present ARFI-Monitored Hemostatic Challenge; a new, potentially alternate method for in vivo hemostasis monitoring that is in development by our group.