Venous thromboembolic events in isolated severe traumatic brain injury

Venous thromboembolism prophylaxis in operative traumatic brain injury

Background

Venous thromboembolism (VTE) is a significant complication in patients with traumatic brain injury (TBI), but the optimal timing of pharmacological prophylaxis in operative cases remains controversial.

Methods

This retrospective study aimed to describe the timing of pharmacological prophylaxis initiation in operative TBI cases, stratified by surgery type, and to report the frequency of worsening postoperative intracranial pathology.

Results

Data from 90 surgical TBI patients were analyzed, revealing that 87.8% received VTE pharmacological prophylaxis at a mean of 85 hours postsurgery. The timing of initiation varied by procedure, with burr holes having the earliest start at a mean of 66 h. Craniotomy and decompressive craniectomy had the longest delay, with means of 116 and 109 h, respectively. Worsening intracranial pathology occurred in 5.6% of patients, with only one case occurring after VTE pharmacological prophylaxis initiation. The overall VTE rate was 3.3%.

Conclusion

These findings suggest that initiating VTE pharmacological prophylaxis between 3 and 5 days postsurgery may be safe in operative TBI patients, with the timing dependent on the procedure's invasiveness. The low frequencies of worsening intracranial pathology and VTE support the safety of these proposed timeframes. However, the study's limitations, including its single-center retrospective nature and lack of a standardized protocol, necessitate further research to confirm these findings and establish evidence-based guidelines for VTE pharmacological prophylaxis in operative TBI patients.

Does Tranexamic Acid Administration Increase the Risk of Thromboembolism?

Introduction Hemorrhage following trauma is one of the leading causes of death worldwide. Venous thromboembolism (VTE) is a common complication of an increased coagulable state, and the risk of VTE following the administration of tranexamic acid (TXA), an antifibrinolytic agent, is still controversial. Our aim is to understand whether there is any association between the administration of TXA and the risk of VTE development. Methods A retrospective cohort study enrolled trauma patients presenting to a level 1 trauma center who received TXA at King Abdulaziz Medical City (KAMC), a tertiary hospital in Riyadh, Saudi Arabia, between 2016 and 2020. Variables included were patients' demographics, comorbidities, laboratory investigations, TXA's route of administration, date of administration, and dose. Finally, the development of VTE in the form of deep vein thrombosis (DVT) or PE and those who died were evaluated. Results A total of 361 adult trauma patients who received TXA were included in the study. Most were males (90.3%) with an average age of 33 years and had a normal BMI (43.3%). Nine patients (2.5%) developed DVT, one of whom died, and five patients (1.4%) developed PE, with no recorded deaths. Conclusion The risk of VTE following the administration of TXA remains controversial and yet to be clearly demonstrated. In this study, there was no significant association between TXA administration and the risk of developing VTE. More research with a larger sample size is needed to identify and recognize any significant risk factors for developing such a condition.

Predictors of outcomes in geriatric patients with moderate traumatic brain injury after ground level falls

Introduction

The elderly population constitutes one of the fastest-growing demographic groups globally. Within this population, mild to moderate traumatic brain injuries (TBI) resulting from ground level falls (GLFs) are prevalent and pose significant challenges. Between 50 and 80% of TBIs in older individuals are due to GLFs. These incidents result in more severe outcomes and extended recovery periods for the elderly, even when controlling for injury severity. Given the increasing incidence of such injuries it becomes essential to identify the key factors that predict complications and in-hospital mortality. Therefore, the aim of this study was to pinpoint the top predictors of complications and in-hospital mortality in geriatric patients who have experienced a moderate TBI following a GLF.

Methods

Data were obtained from the American College of Surgeons' Trauma Quality Improvement Program database. A moderate TBI was defined as a head AIS ≤ 3 with a Glasgow Coma Scale (GCS) 9-13, and an AIS ≤ 2 in all other body regions. Potential predictors of complications and in-hospital mortality were included in a logistic regression model and ranked using the permutation importance method.

Results

A total of 7,489 patients with a moderate TBI were included in the final analyses. 6.5% suffered a complication and 6.2% died prior to discharge. The top five predictors of complications were the need for neurosurgical intervention, the Revised Cardiac Risk Index, coagulopathy, the spine abbreviated injury severity scale (AIS), and the injury severity score. The top five predictors of mortality were head AIS, age, GCS on admission, the need for neurosurgical intervention, and chronic obstructive pulmonary disease.

Conclusion

When predicting both complications and in-hospital mortality in geriatric patients who have suffered a moderate traumatic brain injury after a ground level fall, the most important factors to consider are the need for neurosurgical intervention, cardiac risk, and measures of injury severity. This may allow for better identification of at-risk patients, and at the same time resulting in a more equitable allocation of resources.

A risk prediction model for evaluating thrombosis extension of muscle calf venous thrombosis after craniotomy

Objective

To explore the risk factors of muscle calf venous thrombosis (MCVT) after craniotomy and construct a risk prediction model, so as to provide tool for evaluating the prognosis of MCVT after craniotomy.

Methods

Retrospective analysis was performed on the data of patients undergoing craniotomy complicated with MCVT from January 1, 2018 to December 31, 2020. A prediction model was established by Logistic regression, and the predictive efficacy of the model was tested by ROC curve. The accuracy of the risk model was evaluated by Hosmer-Lemeshow (H-L) test, and the model was verified internally by cross validation.

Results

Among the 446 patients who underwent craniotomy complicated with MCVT, 112 cases (25.11%) had thrombosis extension. D-dimer, Capirini scores, length of hospital stay, malignant tumor, fracture, use of dehydrating agents and hemostatic agents were independently related to thrombosis extension after craniotomy. The area under ROC curve (AUROC) of the prediction model was 0.918 (0.888, 0.942), and the sensitivity and specificity of the maximum Youden index were 85.3% and 78.2%, respectively. H-L test showed that the prediction model was accurate (χ² = 12.426, P = 0.133). The internal verification results of the prediction model showed that the AUROC value of the prediction model is 0.892.

Conclusion

The prediction model has a good prediction efficacy on the prognosis of post-craniotomy patients complicated with MCVT, and can be used as a tool to evaluate the risk of thrombosis extension.

Delayed Cranial Decompression Rates After Initiation of Unfractionated Heparin versus Low-Molecular-Weight Heparin in Traumatic Brain Injury

BACKGROUND

Both unfractionated heparin (UH) and low-molecular-weight heparin (LMWH) are routinely used prophylactically after traumatic brain injury (TBI) to prevent deep vein thrombosis (DVT). Their comparative risk for development or worsening of intracranial hemorrhage necessitating cranial decompression is unclear. Furthermore, the absence of a specific antidote for LMWH may lead to UH being used more often for high-risk patients. This study aims to compare the incidence of delayed cranial decompression occurring after initiation of prophylactic UH versus LMWH using the National Trauma Data Bank.

METHODS

Cranial decompression procedures included craniotomy and craniectomy. Multiple imputation was used for missing data. Propensity score matching was used to account for selection bias between UH and LMWH. The 1:1 matched groups were compared using logistic regression for the primary outcome of postprophylaxis cranial decompression.

RESULTS

A total of 218,594 patients with TBI were included, with 61,998 (28.3%) receiving UH and 156,596 (71.7%) receiving LMWH as DVT prophylaxis. The UH group had higher patient age, body mass index, comorbidity rates, Injury Severity Score, and worse motor Glasgow Coma Scale score. After the UH and LMWH groups were matched for these factors, logistic regression showed lower rates of postprophylaxis cranial decompression for the LMWH group (odds ratio, 0.13; 95% confidence interval, 0.11-0.16; P < 0.001).

CONCLUSIONS

Despite the absence of a specific antidote, LMWH was associated with lower rates of need for post-DVT-prophylaxis in craniotomy/craniectomy. This finding questions the notion of UH being safer for patients with TBI because it can be readily reversed. Randomized studies are needed to elucidate causality.

Venous thromboembolism prophylaxis and related outcomes in patients with traumatic brain injury and prolonged intensive care unit stay

Objective: Traumatic brain injury (TBI) patients with prolonged intensive care unit (ICU) stay are at risk of secondary intracranial haemorrhage (ICH) and venous thromboembolism (VTE). We aimed to study VTE prophylaxis, secondary ICH, and VTE prevalence and outcomes in this population. Design: Retrospective observational study. Setting: Level 1 trauma centre ICU. Patients: One hundred TBI patients receiving prolonged ICU treatment (≥ 7 days). Interventions: We collected data from medical records, pathology and radiology systems, and hospital and ICU admission databases. We analysed patient characteristics, interventions, episodes and types of secondary ICH and VTE, and timing and dosage of VTE prophylaxis. Results: Data from the 100 patients in our study showed that early use of compression stockings and pneumatic calf compression was common (75% and 91% in the first 3 days, respectively). VTE chemoprophylaxis, however, was only used in 14% of patients by Day 3 and > 50% by Day 10. We observed VTE in 12 patients (10 as pulmonary embolism), essentially all after Day 6. Radiologically confirmed secondary ICH occurred in 43% of patients despite normal coagulation. However, 72% of ICH events (42/58) were radiologically mild, and the median time of onset of ICH was Day 1, when only 3% of patients were on chemical prophylaxis. Moreover, 82% of secondary ICH events (48/58) occurred in the first 3 days, with no severe ICH thereafter. Conclusions: In TBI patients receiving prolonged ICU treatment, early chemical VTE prophylaxis was uncommon. Early secondary ICH was common and mostly radiologically mild, whereas later secondary ICH was essentially absent. In contrast, early VTE was essentially absent, whereas later VTE was relatively common. Earlier chemical VTE prophylaxis and/or ultrasound screening in this population appears logical.

Review of Prothrombin Complex Concentrates Use in Apixaban and Rivaroxaban Associated Intracranial Hemorrhages

STUDY OBJECTIVE

Summarize the studies evaluating the use of 4-factor prothrombin complex concentrates in the management of apixaban and rivaroxaban associated intracranial hemorrhages.

METHODS

A PubMed literature search was conducted for articles published between 2013 and 2020 which contained the following terms in their title: (1) apixaban, rivaroxaban, or factor Xa inhibitor*, and (2) prothrombin complex concentrate*.

RESULTS

Eighteen observational studies were included. When a ∼25 units/kg (range: 25-26.9 units/kg) non-activated 4 factor prothrombin complex concentrate dose was administered, the hemostatic effectiveness rates were ≥ 79% in 2/4 studies that utilized the Sarode et al criteria, in comparison to 4/5 studies that administered a 50 units/kg dose. The mortality rates were < 20% in 7/9 studies with hemostatic effectiveness rates ≥ 79%. Mortality rates were lower in the studies demonstrating higher hemostatic effectiveness rates and including patients with higher Glasgow coma scale scores and lower intracerebral hemorrhage volumes. Overall, the thromboembolic event rates were 0-18%, with 16/18 studies demonstrating rates ≤ 10%. The thromboembolic event rates were not dose or agent dependent.

CONCLUSION

Rates of hemostatic effectiveness were influenced by the definition of hemostatic effectiveness, dose administered, and patient severity. Studies suggest that higher doses may result in higher hemostatic effectiveness rates without increasing the risk of experiencing a thromboembolic event. This review may be used by providers to modify or validate their reversal strategy approach until well designed studies are available.

Prediction of in-hospital mortality in patients on mechanical ventilation post traumatic brain injury: machine learning approach

Background

The study aimed to introduce a machine learning model that predicts in-hospital mortality in patients on mechanical ventilation (MV) following moderate to severe traumatic brain injury (TBI).

Methods

A retrospective analysis was conducted for all adult patients who sustained TBI and were hospitalized at the trauma center from January 2014 to February 2019 with an abbreviated injury severity score for head region (HAIS) ≥ 3. We used the demographic characteristics, injuries and CT findings as predictors. Logistic regression (LR) and Artificial neural networks (ANN) were used to predict the in-hospital mortality. Accuracy, area under the receiver operating characteristics curve (AUROC), precision, negative predictive value (NPV), sensitivity, specificity and F-score were used to compare the models` performance.

Results

Across the study duration; 785 patients met the inclusion criteria (581 survived and 204 deceased). The two models (LR and ANN) achieved good performance with an accuracy over 80% and AUROC over 87%. However, when taking the other performance measures into account, LR achieved higher overall performance than the ANN with an accuracy and AUROC of 87% and 90.5%, respectively compared to 80.9% and 87.5%, respectively. Venous thromboembolism prophylaxis, severity of TBI as measured by abbreviated injury score, TBI diagnosis, the need for blood transfusion, heart rate upon admission to the emergency room and patient age were found to be the significant predictors of in-hospital mortality for TBI patients on MV.

Conclusions

Machine learning based LR achieved good predictive performance for the prognosis in mechanically ventilated TBI patients. This study presents an opportunity to integrate machine learning methods in the trauma registry to provide instant clinical decision-making support.

Therapeutic anticoagulation in patients with traumatic brain injuries and pulmonary emboli

BACKGROUND

Patients with traumatic intracranial hemorrhage (ICH) and concomitant pulmonary embolus (PE) have competing care needs and demand a careful balance of anticoagulation (AC) versus potential worsening of their ICH. The goal of this study is to determine the safety of therapeutic AC for PE in patients with ICH.

METHODS

This is a retrospective single-center study of patients older than 16 years with concomitant ICH and PE occurring between June 2013 and December 2017. Early AC was defined as within 7 days of injury or less; late was defined as after 7 days. Primary outcomes included death, interventions for worsening ICH following AC, and pulmonary complications. Multivariate logistic regression was used to evaluate for clinical and demographic factors associated with worsening traumatic brain injury (TBI), and recursive partitioning was used to differentiate risk in groups.

RESULTS

Fifty patients met criteria. Four did not receive any AC and were excluded. Nineteen (41.3%) received AC early (median, 4.1; interquartile range, 3.1-6) and 27 (58.7%) received AC late (median, 14; interquartile range, 9.7-19.5). There were four deaths in the early group, and none in the late cohort (21.1% vs. 0%, p = 0.01). Two deaths were due to PE and the others were from multi-system organ failure or unrecoverable underlying TBI. Three patients in the early group, and two in the late, had increased ICH on computed tomography (17.6% vs. 7.4%, p = 0.3). None required intervention.

CONCLUSION

This retrospective study failed to find instances of clinically significant progression of TBI in 46 patients with computed tomography-proven ICH after undergoing AC for PE. Therapeutic AC is not associated with worse outcomes in patients with TBI, even if initiated early. However, two patients died from PE despite AC, underlining the severity of the disease. Intracranial hemorrhage should not preclude AC treatment for PE, even early after injury.

LEVEL OF EVIDENCE

Care management, Level IV.

Post-TBI splenectomy may exacerbate coagulopathy and platelet activation in a murine model

INTRODUCTION

Traumatic brain injury (TBI) induces acute hypocoagulability, subacute hypercoagulability, and persistently elevated risk for thromboembolic events. Splenectomy is associated with increased mortality in patients with moderate or severe TBI. We hypothesized that the adverse effects of splenectomy in TBI patients may be secondary to the exacerbation of pathologic coagulation and platelet activation changes.

METHODS

An established murine weight-drop TBI model was utilized and a splenectomy was performed immediately following TBI. Sham as well as TBI and splenectomy alone mice were used as injury controls. Mice were sacrificed for blood draws at 1, 6, and 24 h, as well as 7 days post-TBI. Viscoelastic coagulation parameters were assessed by rotational thromboelastometry (ROTEM) and platelet activation was measured by expression of P-selectin via flow cytometry analysis of platelet rich plasma samples.

RESULTS

At 6 h following injury, TBI/splenectomy demonstrated hypocoagulability with prolonged clot formation time (CFT) compared to TBI alone. By 24 h following injury, TBI/splenectomy and splenectomy mice were hypercoagulable with a shorter CFT, a higher alpha angle, and increased MCF, despite a lower percentage of platelet contribution to clot compared to TBI alone. However, only the TBI/splenectomy continued to display this hypercoagulable state at 7 days. While TBI/splenectomy had greater P-selectin expression at 1-h post-injury, TBI alone had significantly greater P-selectin expression at 24 h post-injury compared to TBI/splenectomy. Interestingly, P-selectin expression remained elevated only in TBI/splenectomy at 7 days post-injury.

CONCLUSION

Splenectomy following TBI exacerbates changes in the post-injury coagulation state. The combination of TBI and splenectomy induces an acute hypocoagulable state that could contribute to an increase in intracranial bleeding. Subacutely, the addition of splenectomy to TBI exacerbates post-injury hypercoagulability and induces persistent platelet activation. These polytrauma effects on coagulation may contribute to the increased mortality observed in patients with combined brain and splenic injuries.

Early Anti-Xa Assay-Guided Low Molecular Weight Heparin Chemoprophylaxis is Safe in Adult Patients with Acute Traumatic Brain Injury

This study evaluated the safety of early anti-factor Xa assay–guided enoxaparin dosing for chemoprophylaxis in patients with TBI. We hypothesized that assay-guided chemoprophylaxis would be comparable in the risk of intracranial hemorrhage (ICH) progression to fixed dosing. An observational analysis of adult patients with blunt traumatic brain injury (TBI) was performed at a Level I trauma center from August 2016 to September 2017. Patients in the assay-guided group were treated with an initial enoxaparin dose of 0.5 mg/kg, with peak anti-factor Xa activity measured four hours after the third dose. Prophylactic range was defined as 0.2 to 0.5 IU/mL with a dose adjustment of ± 10 mg based on the assay result. The assay-guided group was compared with historical fixed-dose controls and to a TBI cohort from the most recent Trauma Quality Improvement Project dataset. Of 179 patients included in the study, 85 were in the assay-guided group and 94 were in the fixed-dose group. Compared with the fixed-dose group, the assay-guided group had a lower Glasgow Coma Score and higher Injury Severity Score. The proportion of severe (Abbreviated Injury Score, head ≥3) TBI, ICH progression, and venous thromboembolism rates were similar between all groups. The assay-guided and fixed-dose groups had chemoprophylaxis initiated earlier than the Trauma Quality Improvement Project group. The assay-guided group had the highest percentage of low molecular weight heparin use. Early initiation of enoxaparin anti-factor Xa assay–guided venous thromboembolism chemoprophylaxis has a comparable risk of ICH progression to fixed dosing in patients with TBI. These findings should be validated prospectively in a multicenter study.

Asymptomatic Trauma Patients Screened for Venous Thromboembolism Have a Higher Risk Profile with Lower Rate of Pulmonary Embolism: A Five-Year Single-Institution Experience

Deep vein thrombosis (DVT) is linked to reimbursements and publicly reported metrics. Some hospitals discourage venous duplex ultrasound (VDUS) screening in asymptomatic trauma patients because they often find higher rates of DVT. We aim to evaluate the association between lower extremity (LE) VDUS screening and pulmonary embolism (PE) in trauma patients. Trauma patients admitted to an urban Level-1 trauma center between 2010 and 2015 were retrospectively analyzed. We characterized the association of asymptomatic LE VDUSs with PE, upper extremity DVT, proximal LE DVT, and distal LE DVT by univariate and multivariable logistic regression controlling for confounders. Of the 3959 trauma patients included in our study—after adjusting for covariates related to patient demographics, injury, and procedures—there was a significantly lower likelihood of PE in screened patients (odds ratio (OR) = 0.02, P < 0.001) and a higher rate of distal LE DVT (OR 11.1, P = 0.004). Screening was not associated with higher rates of proximal LE DVTafter adjustment for covariates (OR = 1.8, P = 0.193). PE was associated with patient transfer status, pelvis fracture, and spinal procedures in unscreened patients. After adjusting for covariates, we have shown that LE VDUS asymptomatic screening is associated with lower rates of PE in trauma patients and not associated with higher rates of proximal LE DVT. Our detailed institutional review of a large cohort of trauma patients over five years provides support for ongoing asymptomatic screening and better characterizes venous thromboembolism outcomes than similarly sized purely administrative data reviews. As a retrospective cohort study with a large sample size, no loss to follow-up, and a population with low heterogeneity, this study should be considered as level III evidence for care management.

Prediction of in-hospital mortality in patients with post traumatic brain injury using National Trauma Registry and Machine Learning Approach

BACKGROUND

The use of machine learning techniques to predict diseases outcomes has grown significantly in the last decade. Several studies prove that the machine learning predictive techniques outperform the classical multivariate techniques. We aimed to build a machine learning predictive model to predict the in-hospital mortality for patients who sustained Traumatic Brain Injury (TBI).

METHODS

Adult patients with TBI who were hospitalized in the level 1 trauma center in the period from January 2014 to February 2019 were included in this study. Patients' demographics, injury characteristics and CT findings were used as predictors. The predictive performance of Artificial Neural Networks (ANN) and Support Vector Machines (SVM) was evaluated in terms of accuracy, Area Under the Curve (AUC), sensitivity, precision, Negative Predictive Value (NPV), specificity and F-score.

RESULTS

A total of 1620 eligible patients were included in the study (1417 survival and 203 non-survivals). Both models achieved accuracy over 91% and AUC over 93%. SVM achieved the optimal performance with accuracy 95.6% and AUC 96%.

CONCLUSIONS

for prediction of mortality in patients with TBI, SVM outperformed the well-known classical models that utilized the conventional multivariate analytical techniques.

The Role of Chemoprophylactic Agents in Modulating Platelet Aggregability After Traumatic Brain Injury

BACKGROUND

The pathophysiology behind the subacute but persistent hypercoagulable state after traumatic brain injury (TBI) is poorly understood but contributes to morbidity induced by venous thromboembolism. Because platelets and their microvesicles have been hypothesized to play a role in post-traumatic hypercoagulability, administration of commonly used agents may ameliorate this coagulability. We hypothesized that utilization of aspirin, ketorolac, amitriptyline, unfractionated heparin, or enoxaparin would modulate the platelet aggregation response after TBI.

METHODS

Concussive TBI was induced by weight drop. Mice were then randomized to receive aspirin, ketorolac, amitriptyline, heparin, enoxaparin, or saline control at 2 and 8 h after TBI. Mice were sacrificed at 6 or 24 h after injury to determine coagulability by rotational thromboelastometry (ROTEM), platelet function testing with impedance aggregometry, and microvesicle enumeration. Platelet sphingolipid metabolites were analyzed by mass spectrometry.

RESULTS

ROTEM demonstrated increased platelet contribution to maximum clot firmness at 6 h after TBI in mice that received aspirin or amitriptyline, but this did not persist at 24 h. By contrast, adenosine diphosphate- and arachidonic acid-induced platelet aggregation at 6 h was significantly lower in mice receiving ketorolac, aspirin, and amitriptyline compared with mice receiving saline at 6 h after injury and only arachidonic acid-initiated platelet aggregation was decreased by aspirin at 24 h. There were no differences in microvesicle production at either time point. Platelet sphingosine-1-phosphate levels were decreased at 6 h in the group receiving amitriptyline and increased at 24 h along with platelet ceramide levels at 24 h in the amitriptyline group.

CONCLUSION

After TBI, amitriptyline decreased platelet aggregability and increased contribution to clot in a manner similar to aspirin. The amitriptyline effects on platelet function and sphingolipid metabolites may represent a possible role of the acid sphingomyelinase in the hypercoagulability observed after injury. In addition, inhibition of platelet reactivity may be an underappreciated benefit of low molecular weight heparins, such as enoxaparin.

Early Venous Thromboembolism Chemoprophylaxis After Traumatic Intracranial Hemorrhage

BACKGROUND

Venous thromboembolism is a common complication of traumatic brain injury with an estimated incidence of 25% when chemoprophylaxis is delayed. The timing of initiating prophylaxis is controversial given the concern for hemorrhage expansion.

OBJECTIVE

To determine the safety of initiating venous thromboembolic event (VTE) chemoprophylaxis within 24 h of presentation.

METHODS

We performed a retrospective analysis of patients with traumatic intracranial hemorrhage presenting to a level I trauma center. Patients receiving early chemoprophylaxis (<24 h) were compared to the matched cohort of patients who received heparin in a delayed fashion (>48 h). The primary outcome of the study was radiographic expansion of the intracranial hemorrhage. Secondary outcomes included VTE, use of intracranial pressure (ICP) monitoring, delayed decompressive surgery, and all-cause mortality.

RESULTS

Of 282 patients, 94 (33%) received chemoprophylaxis within 24 h of admission. The cohorts were evenly matched across all variables. The primary outcome occurred in 18% of patients in the early cohort compared to 17% in the delayed cohort (P = .83). Fifteen patients (16%) in the early cohort underwent an invasive procedure in a delayed fashion; this compares to 35 patients (19%) in the delayed cohort (P = .38). Five patients (1.7%) in our study had a VTE during their hospitalization; 2 of these patients received early chemoprophylaxis (P = .75). The rate of mortality from all causes was similar in both groups.

CONCLUSION

Early (<24 h) initiation of VTE chemoprophylaxis in patients with traumatic intracranial hemorrhage appears to be safe. Further prospective studies are needed to validate this finding.

Coagulopathy and haemorrhagic progression in traumatic brain injury: advances in mechanisms, diagnosis, and management

Normal haemostasis depends on an intricate balance between mechanisms of bleeding and mechanisms of thrombosis, and this balance can be altered after traumatic brain injury (TBI). Impaired haemostasis could exacerbate the primary insult with risk of initiation or aggravation of bleeding; anticoagulant use at the time of injury can also contribute to bleeding risk after TBI. Many patients with TBI have abnormalities on conventional coagulation tests at admission to the emergency department, and the presence of coagulopathy is associated with increased morbidity and mortality. Further blood testing often reveals a range of changes affecting platelet numbers and function, procoagulant or anticoagulant factors, fibrinolysis, and interactions between the coagulation system and the vascular endothelium, brain tissue, inflammatory mechanisms, and blood flow dynamics. However, the degree to which these coagulation abnormalities affect TBI outcomes and whether they are modifiable risk factors are not known. Although the main challenge for management is to address the risk of hypocoagulopathy with prolonged bleeding and progression of haemorrhagic lesions, the risk of hypercoagulopathy with an increased prothrombotic tendency also warrants consideration.

Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition

The scope and purpose of this work is 2-fold: to synthesize the available evidence and to translate it into recommendations. This document provides recommendations only when there is evidence to support them. As such, they do not constitute a complete protocol for clinical use. Our intention is that these recommendations be used by others to develop treatment protocols, which necessarily need to incorporate consensus and clinical judgment in areas where current evidence is lacking or insufficient. We think it is important to have evidence-based recommendations to clarify what aspects of practice currently can and cannot be supported by evidence, to encourage use of evidence-based treatments that exist, and to encourage creativity in treatment and research in areas where evidence does not exist. The communities of neurosurgery and neuro-intensive care have been early pioneers and supporters of evidence-based medicine and plan to continue in this endeavor. The complete guideline document, which summarizes and evaluates the literature for each topic, and supplemental appendices (A-I) are available online at https://www.braintrauma.org/coma/guidelines.

Does traumatic brain injury increase the risk for venous thromboembolism in polytrauma patients?

BACKGROUND

Trauma is a major risk factor for venous thromboembolism (VTE). Traumatic brain injury (TBI) is generally considered to further increase the VTE risk, which should prompt routine thromboprophylaxis. However, the associated risk for intracranial hemorrhage often delays anticoagulants. We test the hypothesis that TBI associated with polytrauma results in a higher rate of VTE than polytrauma without TBI.

METHODS

From August 2011 to June 2013, a prospective observational trial with informed consent was performed in 148 intensive care unit (ICU) patients with a Greenfield Risk Assessment Profile score of 10 or greater.

RESULTS

Demographics, Greenfield Risk Assessment Profile scores, the incidence of polytrauma, and mortality were similar, but TBI patients had worse Injury Severity Scores (ISS) (32 vs. 22), longer ICU lengths of stay (21 days vs. 12 days), more hypercoagulable thromboelastogram values on admission (94% vs. 79%), more received unfractionated heparin prophylaxis (65% vs. 36%), and the prophylaxis start date was more than a day later (all p < 0.05). Nevertheless, the VTE rate with TBI was similar to that without TBI (25% vs. 26%, p = 0.507). Furthermore, VTE occurred at similar time points after ICU admission with and without TBI. In both groups, about 30% of the VTEs were detected within 2 days of ICU admission and 50% of the VTEs occurred within 10 days of admission despite chemical and mechanical thromboprophylaxis.

CONCLUSION

In complex polytrauma patients who survived to ICU admission and who were prescreened for high VTE risk, TBI did not further increase the risk for VTE. The most likely explanation is that no single risk factor is necessary or sufficient for VTE development, especially in those who routinely receive chemical and mechanical thromboprophylaxis.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Safety and efficacy of early thromboembolism chemoprophylaxis after intracranial hemorrhage from traumatic brain injury

OBJECT

Patients with traumatic brain injury (TBI) are at risk for development of thromboembolic disease. The use of chemoprophylaxis in this patient group has not fully been characterized. The authors hypothesize that early chemoprophylaxis in patients with TBI is safe and efficacious.

METHODS

In May 2009, a protocol was instituted for patients with TBI where chemoprophylaxis for thromboembolic disease (either 30 mg of Lovenox twice daily or 5000 U of heparin 3 times a day) was initiated 24 hours after an intracranial hemorrhage (ICH) was demonstrated as stable on head CT image. Two cohorts were evaluated: Cohort A included patients from May 2008 through April 2009 who had no routine administration of chemoprophylaxis, and Cohort B included patients from May 2009 through May 2010 after the protocol was instituted. The groups were compared, with the major outcomes being deep venous thrombosis (DVT), pulmonary embolism, and increase in size of ICH.

RESULTS

Of the 312 patients with TBI who were seen during the study course, 236 patients met criteria for inclusion in the study: 107 patients in Cohort A and 129 patients in Cohort B. The DVT rate was 6 occurrences (5.61%) in Cohort A and 0 occurrences (0%) in Cohort B, which was a statistically significant difference (p = 0.0080). Pulmonary embolism was found in 4 patients (3.74%) in Cohort A and 1 patient (0.78%) in Cohort B, a difference that did not reach statistical significance (p = 0.18). Three instances (2.8%) in Cohort A and 1 instance (0.7%) in Cohort B of increased ICH occurred after starting anticoagulation for chemoprophylaxis; this was not statistically different (p = 0.33).

CONCLUSIONS

Use of chemoprophylaxis in TBI 24 hours after stable head CT is safe and decreases the rate of DVT formation.