Pharmacologic venous thromboembolism prophylaxis after traumatic brain injury: a critical literature review

Early venous thromboembolism chemoprophylaxis in traumatic brain injury requiring neurosurgical intervention: Safe and effective

BACKGROUND

Traumatic brain injury patients who require neurosurgical intervention are at the highest risk of worsening intracranial hemorrhage. This subgroup of patients has frequently been excluded from prior research regarding the timing of venous thromboembolism chemoprophylaxis. This study aims to assess the efficacy and safety of early venous thromboembolism chemoprophylaxis in patients with traumatic brain injuries requiring neurosurgical interventions.

METHODS

This is a single-center retrospective review (2016-2020) of traumatic brain injury patients requiring neurosurgical intervention admitted to a level I trauma center. Interventions included intracranial pressure monitoring, subdural drain, external ventricular drain, craniotomy, and craniectomy. Exclusion criteria included neurosurgical intervention after chemoprophylaxis initiation, death within 5 days of admission, and absence of chemoprophylaxis. The total population was stratified into Early (≤72 hours of intervention) versus Late (>72 hours after intervention) chemoprophylaxis initiation.

RESULTS

A total of 351 patients met the inclusion criteria, of whom 204 (58%) had early chemoprophylaxis initiation. Overall, there were no significant differences in baseline and admission characteristics between cohorts. The Early chemoprophylaxis cohort had a statistically significant lower venous thromboembolism rate (5% vs 13%, P < .001) with no increased risk of worsening intracranial hemorrhage (10% vs 13%, P = .44) or neurosurgical reintervention (8% vs 10%, P = .7). On subgroup analysis, a total of 169 patients required either a craniotomy or a craniectomy before chemoprophylaxis. The Early chemoprophylaxis cohort had statistically significant lower venous thromboembolism rates (2% vs 11%, P < .001) with no increase in intracranial hemorrhage (8% vs 11%, P = .6) or repeat neurosurgical intervention (8% vs 10%, P = .77).

CONCLUSION

Venous thromboembolism prophylaxis initiation within 72 hours of neurosurgical intervention is safe and effective. Further prospective research is warranted to validate the results of this study.

Factors Associated with Venous Thromboembolism Development in Patients with Traumatic Brain Injury

BACKGROUND

Venous thromboembolic (VTE) events are a major concern in trauma and intensive care, with the prothrombotic state caused by traumatic brain injury (TBI) increasing the risk in affected patients. We sought to identify critical demographic and clinical variables and determine their influence on subsequent VTE development in patients with TBI.

METHODS

This was a cross-sectional study with data retrospectively collected from 818 patients with TBI admitted to a level I trauma center in 2015-2020 and placed on VTE prophylaxis.

RESULTS

The overall VTE incidence was 9.1% (7.6% deep vein thrombosis, 3.2% pulmonary embolism, 1.7% both). The median time to diagnosis was 7 days (interquartile range 4-11) for deep vein thrombosis and 5 days (interquartile range 3-12) for pulmonary embolism. Compared with those who did not develop VTE, patients who developed VTE were younger (44 vs. 54 years, p = 0.02), had more severe injury (Glasgow Coma Scale 7.5 vs. 14, p = 0.002, Injury Severity Score 27 vs. 21, p < 0.001), were more likely to have experienced polytrauma (55.4% vs. 34.0%, p < 0.001), more often required neurosurgical intervention (45.9% vs. 30.5%, p = 0.007), more frequently missed ≥ 1 dose of VTE prophylaxis (39.2% vs. 28.4%, p = 0.04), and were more likely to have had a history of VTE (14.9% vs. 6.5%, p = 0.008). Univariate analysis demonstrated that 4-6 total missed doses predicted the highest VTE risk (odds ratio 4.08, 95% confidence interval 1.53-10.86, p = 0.005).

CONCLUSIONS

Our study highlights patient-specific factors that are associated with VTE development in a cohort of patients with TBI. Although many of these are unmodifiable patient characteristics, a threshold of four missed doses of chemoprophylaxis may be particularly important in this critical patient population because it can be controlled by the care team. Development of intrainstitutional protocols and tools within the electronic medical record to avoid missed doses, particularly among patients who require operative interventions, may result in decreasing the likelihood of future VTE formation.

Effects of Early Chemoprophylaxis in Traumatic Brain Injury and Risk of Venous Thromboembolism

BACKGROUND

The optimal timing to initiate venous thromboembolism (VTE) prophylaxis in patients with a traumatic brain injury (TBI) is still unknown. We designed a study to determine the effect that timing of initiation of VTE prophylaxis has on VTE rates in TBI patients.

METHODS

Patient records were obtained from 32 level 1 and 2 trauma centers in the Michigan Trauma Quality Improvement Program from 2008 to 2018. Overall, 5589 patients with a TBI were included and split into cohorts based on VTE prophylaxis initiation time. Outcomes included rate of VTE, mortality, and serious in-hospital complications.

RESULTS

There were nine patients (1.3%) in the <24 hour group with a VTE as compared to 36 (2.6%) in the 24-48 hour group, 51 (4.1%) in the 48-72 hour group, and 181 (8.1%) in the >72 hour group (P < .001). The adjusted odds of VTE were significantly greater in patients initiated within 48-72 hours (AOR 2.861, 95% CI 1.271-6.439) and >72 hours (AOR 3.963, 95% CI 1.824-8.612) compared to <24 hours. Patients that received VTE prophylaxis within 24 hours had similar rates of serious in-hospital complication as patients initiated within 24-48 hours (AOR .956, 95% CI .637-1.434) and 48-72 hour (AOR 1.132, 95% CI .757-1.692) but less than the >72 hour group (AOR 1.662, 95% CI 1.154-2.393) groups.

DISCUSSION

Patients initiated on VTE prophylaxis within 48 hours of presentation had lower incidence of VTE without a significant increase in serious complications.

Association of Venous Thromboembolism Prophylaxis After Neurosurgical Intervention for Traumatic Brain Injury With Thromboembolic Complications, Repeated Neurosurgery, and Mortality

Importance

There is a lack of evidence regarding the effectiveness and safety of pharmacologic venous thromboembolism (VTE) prophylaxis among patients who undergo neurosurgical interventions for traumatic brain injury (TBI).

Objective

To measure the association between timing of VTE prophylaxis after urgent neurosurgical intervention for TBI and thromboembolic and intracranial complications.

Design, Setting, and Participants

This retrospective cohort study included adult patients (aged ≥16 years) who underwent urgent neurosurgical interventions (craniotomy/craniectomy or intracranial monitor/drain insertion within 24 hours after admission) for TBI at level 1 and 2 trauma centers participating in the American College of Surgeons Trauma Quality Improvement Program between January 1, 2012, and December 31, 2016. Data were analyzed from January to August 2020.

Exposures

Timing of pharmacologic VTE prophylaxis initiation after urgent neurosurgical intervention (prophylaxis delay) measured in days (24-hour periods).

Main Outcomes and Measures

The primary outcome was VTE (deep vein thrombosis or pulmonary embolism). Secondary outcomes were repeated neurosurgery (neurosurgical reintervention after initiation of VTE prophylaxis) and mortality. Hierarchical logistic regression models were used to evaluate the association between prophylaxis delay and each outcome at the patient level and were adjusted for patient baseline and injury characteristics.

Results

The study included 4951 patients (3676 [74%] male; median age, 50 years [IQR, 31-64 years]) who underwent urgent neurosurgical intervention for TBI at 304 trauma centers. The median prophylaxis delay was 3 days (IQR, 1-5 days). After adjustment for patient baseline and injury characteristics, prophylaxis delay was associated with increased odds of VTE (adjusted odds ratio [aOR], 1.08 per day; 95% CI, 1.04-1.12). Earlier initiation of prophylaxis was associated with increased risk of repeated neurosurgery. During the first 3 days, each additional day of prophylaxis delay was associated with a 28% decrease in odds of repeated neurosurgery (aOR, 0.72 per day; 95% CI, 0.59-0.88). After 3 days, each additional day of prophylaxis delay was associated with an additional 15% decrease in odds of repeated neurosurgery (aOR, 0.85 per day; 95% CI, 0.80-0.90). Earlier prophylaxis was associated with greater mortality among patients who initially underwent intracranial monitor/drain procedures, such that each additional day of prophylaxis delay was associated with decreased odds of death (aOR, 0.94 per day; 95% CI, 0.89-0.99).

Conclusions and Relevance

In this cohort study of patients who underwent urgent neurosurgical interventions for TBI, early pharmacologic VTE prophylaxis was associated with reduced risk of thromboembolism. However, earlier initiation of prophylaxis was associated with increased risk of repeated neurosurgery. These findings suggest that although timely initiation of prophylaxis should be prioritized, caution should be used particularly during the first 3 days after the index procedure, when this risk appears to be highest.

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.

Progression of Intracranial Hemorrhage After Chemical Prophylaxis Using Low-Molecular-Weight Heparin in Patients With Traumatic Brain Injury

INTRODUCTION

Chemical prophylaxis using low-molecular-weight heparin (LMWH) is considered a standard of care for venous thromboembolism in trauma patients. Our center performs a head computed tomography (CT) scan 24 hours after initiation with prophylactic LMWH in the setting of a known traumatic brain injury (TBI). The purpose was to determine the overall incidence of ICH progression after chemoprophylaxis in patients with a TBI.

METHODS

This retrospective study was performed at a Level I trauma center, from 1/1/2014 to 12/31/2017. Study patients were drawn from the institution's trauma registry based on Abbreviated Injury Score codes.

RESULTS

778 patients met all inclusion criteria after initial chart review. The proportion of patients with an observed radiographic progression of intracranial hemorrhage after LMWH was 5.8%. 3.1% of patients had a change in clinical management. Observed radiographic progression after LMWH prophylaxis and the presence of SDH on initial CT, the bilateral absence of pupillary response in the emergency department, and a diagnosis of dementia were found to have statistically significant correlation with bleed progression after LMWH was initiated.

CONCLUSION

Over a 4-year period, the use of CT to evaluate for radiographic progression of traumatic intracranial hemorrhage 24 hours after receiving LMWH resulted in a change in clinical management for 3.1% of patients. The odds of intracranial hemorrhage progression were approximately 6.5× greater in patients with subdural hemorrhage on initial CT, 3.1× greater in patients with lack of bilateral pupillary response in ED, and 4.2× greater in patients who had been diagnosed with dementia.

Effective use of weight-based enoxaparin for deep vein thrombosis chemoprophylaxis in patients with traumatic brain injury

BACKGROUND

Enoxaparin is the recommended agent for deep vein thrombosis (DVT) chemoprophylaxis in trauma patients. Current literature suggests weight-based dosing is superior to standard dosing for adequate chemoprophylaxis. Literature regarding the use of weight-based enoxaparin in the setting of traumatic brain injury (TBI) however is limited.

METHODS

A retrospective analysis of adult trauma patients admitted between January 1, 2018 to February 28, 2019 was performed. Sixty-six patients with TBI receiving weight-based enoxaparin met inclusion criteria. Incidence of intracranial hemorrhage (ICH) expansion was the primary endpoint. Newly diagnosed venous thromboembolism (VTE) and death were secondary endpoints.

RESULTS

Two patients, out of sixty-six, had progression of their TBI requiring surgical intervention. Newly diagnosed VTE occurred in one patient. No deaths were due to ICH expansion or VTE.

CONCLUSIONS

Use of weight-based enoxaparin dosing in the setting of TBI shows promise without an increased incidence of ICH expansion when compared to other studies. Level of Evidence and Study Type: Level IV, Therapeutic.

Low Vitamin D Level Is Associated with Acute Deep Venous Thrombosis in Patients with Traumatic Brain Injury

Vitamin D and its association with venous thromboembolism (VTE) have been studied in common rehabilitation populations, such as spinal cord injury and ischemic stroke groups. This study explores the relationship between vitamin D levels and acute deep venous thrombosis (DVT) in the traumatic brain injury (TBI) population. This is a retrospective cohort study that analyzes the relationship between vitamin D levels and the prevalence of DVT during acute inpatient rehabilitation. In this population, 62% (117/190) of patients had low vitamin D levels upon admission to acute rehabilitation. Furthermore, 21% (24/117) of patients in the low vitamin D group had acute DVT during admission to acute rehabilitation. In contrast, only 8% (6/73) of patients in the normal vitamin D group had acute DVT during admission to acute rehabilitation. Fisher’s exact tests revealed significant differences between individuals with low and normal vitamin D levels (p = 0.025). In conclusion, a vitamin D level below 30 ng/mL was associated with increased probability of the occurrence of acute DVT in individuals with moderate–severe TBI.

Timing of Restarting Anticoagulation and Antiplatelet Therapies After Traumatic Subdural Hematoma-A Single Institution Experience

BACKGROUND

There is a paucity of information regarding the optimal timing of restarting antiplatelet therapy (APT) and anticoagulation therapy (ACT) after traumatic subdural hematoma (tSDH). Therefore, we sought to report our experience at a single level 1 trauma center with regard to restarting APT and/or ACT after tSDH.

METHODS

A total of 456 consecutive records were reviewed for unplanned hematoma evacuation within 90 days of discharge and thrombotic/thromboembolic events before restarting APT and/or ACT.

RESULTS

There was no difference in unplanned hematoma evacuation rate in patients not receiving APT or ACT (control) compared with those necessitating APT and/or ACT (6.4% control, 6.9% APT alone, 5.8% ACT alone, 5.4% APT and ACT). There was an increase in post-tSDH thrombosis/thromboembolism in patients needing to restart ACT (1.9% APT alone, P = 0.53 vs. control; 5.8% ACT alone, P = 0.04 vs. control; 16% APT and ACT; P < 0.001 vs. control). Subgroup analysis revealed that patients with coronary artery disease necessitating APT and patients with atrial fibrillation necessitating ACT had higher thrombosis/thromboembolism rates compared with controls (1.0% control vs. 6.1% coronary artery disease, P = 0.02; 1.0% control vs. 10.1% atrial fibrillation, P < 0.001). The median restart time of ACT was approximately 1 month after trauma; APT was restarted 2-4 weeks after trauma depending on clinical indication.

CONCLUSIONS

Patients requiring reinitiation of APT and/or ACT after tSDH were at elevated risk of thrombotic/thromboembolic events but not unplanned hematoma evacuation. Therefore, patients should be followed closely until APT and/or ACT are restarted, and consideration for earlier reinitiation of blood thinners should be given on a case-by-case basis.

Platelet Function Changes in a Time-Dependent Manner Following Traumatic Brain Injury in a Murine Model

Traumatic brain injury (TBI) results in systemic changes in coagulation and inflammation that contribute to post-traumatic morbidity and mortality. The potential interaction of platelets and pro-inflammatory cytokines in the modulation of coagulation, microthrombosis, and venous thromboembolic events after moderate TBI has not been determined. Using a murine model, we hypothesized that the degree of platelet-induced coagulation varies depending on the platelet aggregation agonist platelet-induced coagulation changes in a time-dependent manner following TBI, and changes in platelet-induced coagulation are mirrored by changes in the levels of circulating pro-inflammatory cytokines. An established weight-drop model was used to induce TBI in anesthetized mice. Blood samples were collected at intervals after injury for measurements of platelet count, serum fibrinogen, pro-inflammatory cytokines, and determination of soluble P-selectin levels. Thromboelastometry was used to evaluate changes in hemostasis. Platelet function was determined using whole blood impedance aggregometry. Ten minutes following TBI, adenosine diphosphate-induced platelet aggregation decreased as measured by platelet aggregometry. Despite no changes in platelet counts and serum fibrinogen, platelet aggregation, pro-inflammatory cytokines, and soluble P-selectin were increased at 6 h after TBI. Rotation thromboelastometry demonstrated increased maximal clot firmness at 6 h. Platelet function and coagulability returned to baseline levels 24 h following head injury. Our data demonstrate that after TBI, acute platelet dysfunction occurs followed by rebound platelet hyperaggregation. Alterations in post-TBI platelet aggregation are reflected in whole blood thromboelastometry and are temporally associated with the systemic pro-inflammatory response.

Anticoagulant prophylaxis against venous thromboembolism following severe traumatic brain injury: A prospective observational study and systematic review of the literature

OBJECTIVES

Venous thromboembolism (VTE) is a serious complication following severe traumatic brain injury (TBI), however, anticoagulant prophylaxis remains controversial due to concerns of intracranial hemorrhage (ICH) progression. We examined anticoagulant prophylaxis practice patterns at a major trauma centre and determined risk estimates for VTE and ICH progression classified by timing of anticoagulant initiation.

PATIENTS AND METHODS

A 1-year prospective analysis of consecutive patients with severe TBI admitted to a Level-I trauma centre was conducted. In addition, we systematically reviewed the literature to identify studies on VTE and anticoagulant prophylaxis after severe TBI.

RESULTS

64 severe TBI patients were included. 83% of patients received anticoagulant prophylaxis, initiated ≥3d post-TBI in 67%. The in-hospital VTE incidence was 16% and there was no significant difference between patients who received early (<3d) versus late (≥3d) prophylaxis (10% vs. 16%). Rates of ICH progression (0% vs. 7%) were similar between groups. Our systematic review identified 5 studies with VTE rates ranging from 5 to 10% with prophylaxis, to 11-30% without prophylaxis. The effect of timing of anticoagulant prophylaxis initiation on ICH progression was not reported in any study.

CONCLUSION

VTE is a common complication after severe TBI. Anticoagulant prophylaxis is often started late (≥3d) post-injury. Randomized trials are justifiable and necessary to provide practice guidance with regards to optimal timing of anticoagulant prophylaxis.

Increasing Adherence to Brain Trauma Foundation Guidelines for Hospital Care of Patients With Traumatic Brain Injury

BACKGROUND

The Brain Trauma Foundation has developed treatment guidelines for the care of patients with acute traumatic brain injury. The Adam Williams Initiative is a program established to provide education and resources to encourage hospitals across the United States to incorporate the guidelines into practice.

OBJECTIVE

To explore the relationship in hospitals between participation in the Adam Williams Initiative and adherence to the Brain Trauma Foundation guidelines for patients with acute traumatic brain injury.

METHOD

Hospitals that participated in the Adam Williams Initiative entered data into an online tracking system of patients with traumatic brain injury for at least 2 years after the initial site training. Data included baseline hospital records and daily records on hospital care of patients with traumatic brain injury, including blood pressure, intracranial pressure, cerebral perfusion pressure, oxygenation, and other data relevant to the 15 key metrics in the Brain Trauma Foundation guidelines.

RESULTS

The 16 hospitals funded by the Adam Williams Initiative had good overall adherence to the 15 key metrics of the recommendations detailed in the Brain Trauma Foundation guidelines. Variability in results was primarily due to data collection methods and analysis.

CONCLUSIONS

The Adam Williams Initiative helps promote adherence to the Brain Trauma Foundation guidelines for hospital care of patients with traumatic brain injury by providing a platform for developing and standardizing best practices. Participation in the initiative is associated with high adherence to clinical guidelines, a situation that may subsequently improve care and outcomes for patients with traumatic brain injury.

A Systematic Review of the Risks and Benefits of Venous Thromboembolism Prophylaxis in Traumatic Brain Injury

BACKGROUND

Patients suffering from traumatic brain injury (TBI) are at increased risk of venous thromboembolism (VTE). However, initiation of pharmacological venous thromboprophylaxis (VTEp) may cause further intracranial hemorrhage. We reviewed the literature to determine the postinjury time interval at which VTEp can be administered without risk of TBI evolution and hematoma expansion.

METHODS

MEDLINE and EMBASE databases were searched. Inclusion criteria were studies investigating timing and safety of VTEp in TBI patients not previously on oral anticoagulation. Two investigators extracted data and graded the papers' levels of evidence. Randomized controlled trials were assessed for bias according to the Cochrane Collaboration Tool and Cohort studies were evaluated for bias using the Newcastle-Ottawa Scale. We performed univariate meta-regression analysis in an attempt to identify a relationship between VTEp timing and hemorrhagic progression and assess study heterogeneity using an I 2 statistic.

RESULTS

Twenty-one studies were included in the systematic review. Eighteen total studies demonstrated that VTEp postinjury in patients with stable head computed tomography scan does not lead to TBI progression. Fourteen studies demonstrated that VTEp administration 24 to 72 hours postinjury is safe in patients with stable injury. Four studies suggested that administering VTEp within 24 hours of injury in patients with stable TBI does not lead to progressive intracranial hemorrhage. Overall, meta-regression analysis demonstrated that there was no relationship between rate of hemorrhagic progression and VTEp timing.

CONCLUSIONS

Literature suggests that administering VTEp 24 to 48 hours postinjury may be safe for patients with low-hemorrhagic-risk TBIs and stable injury on repeat imaging.

Routine repeat head CT may not be necessary for patients with mild TBI

Background

Routine repeat cranial CT (RHCT) is standard of care for CT-verified traumatic brain injury (TBI). Despite mixed evidence, those with mild TBI are subject to radiation and expense from serial CT scans. Thus, we investigated the necessity and utility of RHCT for patients with mild TBI. We hypothesized that repeat head CT in these patients would not alter patient care or outcomes.

Methods

We retrospectively studied patients suffering from mild TBI (Glasgow Coma Scale (GCS) score 13–15) and treated at the R Adams Cowley Shock Trauma Center from November 2014 through January 2015. The primary outcome was the need for surgical intervention. Outcomes were compared using paired Student’s t-test, and stratified by injury on initial CT, GCS change, demographics, and presenting vital signs (mean ± SD).

Results

Eighty-five patients met inclusion criteria with an average initial GCS score=14.6±0.57. Our center sees about 2800 patients with TBI per year, or about 230 per month. This includes patients with concussions. This sample represents about 30% of patients with TBI seen during the study period. Ten patients required operation (four based on initial CT and others for worsening GCS, headaches, large unresolving injury). There was progression of injury on repeat CT scan in only two patients that required operation, and this accompanied clinical deterioration. The mean brain Abbreviated Injury Scale (AIS) score was 4.8±0.3 for surgical patients on initial CT scan compared with 3.4±0.6 (P<0.001) for non-surgical patients. Initial CT subdural hematoma size was 1.1±0.6 cm for surgical patients compared with 0.49±0.3 cm (P=0.05) for non-surgical patients. There was no significant difference between intervention groups in terms of other intracranial injuries, demographics, vital signs, or change in GCS. Overall, 75 patients that did not require surgical intervention received RHCT. At $340 per CT, $51 000 was spent on unnecessary imaging ($367 000/year, extrapolated).

Discussion

In an environment of increased scrutiny on healthcare expenditures, it is necessary to question dogma and eliminate unnecessary cost. Our data questions the use of routine repeat head CT scans in every patient with anatomic TBI and suggests that clinically stable patients with small injury can simply be followed clinically.

Level of evidence

Level III.

Neurosurgical applications of viscoelastic hemostatic assays

Patients taking antithrombotic agents are very common in neurosurgical practice. The perioperative management of these patients can be extremely challenging especially as newer agents, with poorly defined laboratory monitoring and reversal strategies, become more prevalent. This is especially true with emergent cases in which rapid reversal of anticoagulation is required and the patient’s exact medical history is not available. With an aging patient population and the associated increase in diseases such as atrial fibrillation, it is expected that the use of these agents will continue to rise in coming years. Furthermore, thromboembolic complications such as deep venous thrombosis, pulmonary embolism, and myocardial infarction are common complications of major surgery. These trends, in conjunction with a growing understanding of the hemostatic process and its contribution to the pathophysiology of disease, stress the importance of the complete evaluation of a patient’s hemostatic profile in guiding management decisions. Viscoelastic hemostatic assays (VHAs), such as thromboelastography and rotational thromboelastometry, are global assessments of coagulation that account for the cellular and plasma components of coagulation. This FDA-approved technology has been available for decades and has been widely used in cardiac surgery and liver transplantation. Although VHAs were cumbersome in the past, advances in software and design have made them more accurate, reliable, and accessible to the neurosurgeon. VHAs have demonstrated utility in guiding intraoperative blood product transfusion, identifying coagulopathy in trauma, and managing postoperative thromboprophylaxis. The first half of this review aims to evaluate and assess VHAs, while the latter half seeks to appraise the evidence supporting their use in neurosurgical populations.

Acute Management of Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability in patients with trauma. Management strategies must focus on preventing secondary injury by avoiding hypotension and hypoxia and maintaining appropriate cerebral perfusion pressure (CPP), which is a surrogate for cerebral blood flow. CPP can be maintained by increasing mean arterial pressure, decreasing intracranial pressure, or both. The goal should be euvolemia and avoidance of hypotension. Other factors that deserve important consideration in the acute management of patients with TBI are venous thromboembolism, stress ulcer, and seizure prophylaxis, as well as nutritional and metabolic optimization.

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.

Impact of practice change in reducing venous thromboembolism in neurocritical overweight patients: 2008-2014

Publications regarding early initiating venous thromboembolism (VTE) prophylaxis have been available since the early 1990s. These recommendations became available in current guidelines on and after 2012. The purpose of this study is to review the practice change in reducing the incidence of VTE in brain injury patients from 2008 to 2014. This was a single-center, retrospective, observational, cohort study. Data was extracted from our data base that included patients over 100 kg from January 2008 to August 2014. Included were all patients admitted with a primary diagnosis of acute brain and spinal injury to neurocritical care unit. Clinical endpoints examined were incidence of bleeding and VTE. A total of 509 patients who met the inclusion criteria were divided into two groups: The previous group (n = 212) included patients from 2008 to 2010, and the recent group (n = 297) included patients from 2011 to 2014. The time for initiating VTE prophylaxis from admission was (median, IQR) 73 h (37-140) vs. 34 h (20-46); p < 0.01. There were no differences in major and minor bleeding complications. Discontinuation of VTE prophylaxis for association with progressive bleeding was not documented in any of the study patients. The incidence of VTE was 10 % (22/212) vs. 5 % (15/297); p = 0.02. In hospital LOS in days was 16 (10-26) vs. 7 (4-15); P < 0.01. In multivariable logistic regression analysis, only the time of the initiation VTE prophylaxis after admission was significantly associated with the occurrence of VTE (median, IQR) 70 h (37-158) vs. 36 h (20-63); OR 1.004, 95 % CI 1.001-1.007; P < 0.01. In this 6-year review of data, early initiation of VTE prophylaxis has decreased the incidence of VTE without clinically documented bleeding complications.

Lethal Trauma Pulmonary Embolism is a Black Swan Event in Patients at Risk for Deep Vein Thrombosis: An Evidence-Based Review

We delineated the incidence of trauma patient pulmonary embolism (PE) and risk conditions by performing a systematic literature review of those at risk for deep vein thrombosis (DVT). The PE proportion was 1.4 per cent (95% confidence interval = 1.2–1.6) in at-risk patients. Of 10 conditions, PE was only associated with increased age (P < 0.01) or leg injury (P < 0.01; risk ratio = 1.6). As lower extremity DVT (LEDVT) proportions increased, mortality proportions (P = 0.02) and hospital stay (P = 0.0002) increased, but PE proportions did not (P = 0.13). LEDVT was lower with chemoprophylaxis (CP) (4.9%) than without CP (19.1%; P < 0.01). PEwas lower withCP (1.0%) than without CP (2.2%; P = 0.0004). Mortality was lower with CP (6.6%) than without CP (11.6%; P = 0.002). PE was similar with (1.2%) and without (1.9%; P = 0.19) mechanical prophylaxis (MP). LEDVT was lower with MP (8.5%) than without MP (12.2%; P = 0.0005). PE proportions were similar with (1.3%) and without (1.5%; P = 0.24) LEDVTsurveillance. Mortality was higher with LEDVTsurveillance (7.9%) than without (4.8%; P < 0.01). A PE mortality of 19.7 per cent (95% confidence interval = 18–22) 3 a 1.4 per cent PE proportion yielded a 0.28 per cent lethal PE proportion. As PE proportions increased, mortality (P = 0.52) and hospital stay (P = 0.13) did not. Of 176 patients with PE, 76 per cent had no LEDVT. In trauma patients at risk for DVT, PE is infrequent, has a minimal impact on outcomes, and death is a black swan event. LEDVTsurveillance did not improve outcomes. Because PE was not associated with LEDVT and most patients with PE had no LEDVT, preventing, diagnosing, and treating LEDVT may be ineffective PE prophylaxis.

Subarachnoid Hemorrhage and Long-Term Stroke Risk After Traumatic Brain Injury

BACKGROUND

Recent studies suggest that traumatic brain injury (TBI) is a risk factor for subsequent ischemic stroke, even years after the initial insult. The mechanisms of the association remain unclear. The presence of traumatic subarachnoid hemorrhage (tSAH) may mediate the effect of TBI on long-term stroke risk, as it has previously been linked to short-term vasospasm and delayed cerebral ischemia.

METHODS

Using administrative claims data, we conducted a retrospective cohort study of acute care hospitalizations. Patients discharged with a first-recorded diagnosis of tSAH were followed for a primary diagnosis of stroke. They were matched to patients with TBI but not tSAH. Cox proportional hazards modeling was used to assess the association between tSAH and stroke while adjusting for covariates.

RESULTS

We identified 40 908 patients with TBI (20 454 patients with tSAH) who were followed for a mean of 4.3 + 1.8 years. A total of 531 had an ischemic stroke after discharge. There was no significant difference in stroke risk between those with tSAH (1.79%; 95% confidence interval [CI] 1.54%-2.08%) versus without tSAH (2.12%; 95% CI 1.83%-2.44%). The same pattern was found in adjusted analyses even when the group was stratified by age-group or by proxies of TBI severity.

CONCLUSIONS

Our findings do not support a role of tSAH in mediating the association between TBI and protracted stroke risk. Further study is required to elucidate the mechanisms of long-term increased stroke risk after TBI.

Venous thromboembolism prophylaxis in neurosurgical trauma patients

BACKGROUND

Venous thromboembolisms (VTEs) occur more frequently in patients with traumatic brain injuries (TBIs) and spinal cord injuries, yet the use of chemoprophylaxis is controversial. The purpose of this study was to investigate the relationship between the timing of chemical VTE prophylaxis initiation and the development of VTE events in these patients.

METHODS

Prospective data were collected and retrospectively reviewed on 1425 patients sustaining TBIs or spinal injuries from 2010 to 2014. Patients were reviewed with respect to age, gender, injury severity score, Glasgow coma score, and mechanism of injury as well as timing of initiation of chemical VTE prophylaxis and presence or absence of VTE.

RESULTS

Patients who developed a VTE had a significantly longer time to initiation of chemical VTE prophylaxis (6.7 ± 4.9 d versus 4.7 ± 4.9 d, P < 0.001) compared with those that did not develop a VTE. Also, for each 1 d increase in time to prophylaxis initiation, the odds of developing a VTE increased significantly (odds ratio = 1.055, P < 0.001). The combination subarachnoid hemorrhage/subdural hemorrhage group was started on VTE prophylaxis significantly later (8.3 ± 6.1 d versus 6.7 ± 3.9 d, P < 0.01) than the overall TBI group and had a higher incidence of VTE (14.4 versus 10.4%, P = NS). In contrast, patients sustaining isolated spinal injuries received chemical VTE prophylaxis significantly earlier (3.4 ± 4.2 d versus 6.7 ± 3.9 d, P < 0.001) and had a significant decrease in their VTE rate (4.4 versus 10.4%, P < 0.0001) compared with the overall TBI group.

CONCLUSIONS

Patients with VTEs had a significant delay in time to initiation of chemoprophylaxis compared with patients without VTEs. Patients sustaining a TBI had a 2-fold delay in initiation of chemoprophylaxis and an associated 2-fold increase in VTE events compared with patients who sustained spinal injuries. Of those patients who developed a TBI, patients who sustained a combination subarachnoid hemorrhage and/or subdural hemorrhage had a significant delay in initiation of chemoprophylaxis with a higher rate of VTE events.

High dose subcutaneous unfractionated heparin for prevention of venous thromboembolism in overweight neurocritical care patients

Timing and dosing of chemical venous thromboembolism (VTE) prophylaxis in brain injury is controversial. Risk of bleeding while using high dose unfractionated heparin (UFH) in overweight patients to prevent VTE is also unknown. The purpose of this study was to describe the use of subcutaneous heparin 7500 units for VTE prophylaxis in overweight patients. This was a retrospective study comparing patients over 100 kg who received either 7500 units Q8 h (n = 141) (high dose group, HDG), or 5000 units Q8 h (n = 257) (traditional dose group, TDG), of UFH subcutaneously. Both groups had similar rates of bleeding complications. The incidence of drop in hemoglobin by two points in any 24 h was 14 % (20/141) HDG versus 11 % (28/257) TDG; P = 0.33. Hemoglobin drop by two points from baseline was 57 % (81/141) HDG versus 51 % (132/257) TDG; P = 0.24. The need for pRBC transfusion was 26 % (36/141) HDG versus 20 % (52/257) TDG; P = 0.22. An increase in aPTT from baseline by two times was 4 % (5/141) HDG versus 4 % (9/257) TDG, P = 0.59. Discontinuation of heparin therapy for association with progressive bleeding was not documented in any patients. No differences in minor bleeding complications were observed. There was no difference in the incidence of VTE: 5.7 % (8/141) HDG versus 9.3 % (24/257) TDG; P = 0.2. In univariate and multivariable logistic regression analysis, only the time of the initiation of heparin after admission was associated with the occurrence of VTE (median, IQR) 46 h (17-86) HDG versus 105 h (56-167) TDG; OR 1.2 (1.1-1.3); P < 0.001. High dose subcutaneous UFH was not associated with an increased risk of bleeding, nor did it decrease the incidence of VTE in overweight patients.

A Systematic Review of the Benefits and Risks of Anticoagulation Following Traumatic Brain Injury

OBJECTIVE

To synthesize the existing literature on benefits and risks of anticoagulant use after traumatic brain injury (TBI).

DESIGN

Systematic review. A literature search was performed in MEDLINE, International Pharmaceutical Abstracts, Health Star, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) on October 11, 2012, and updated on September 2, 2013, using terms related to TBI and anticoagulants.

MAIN MEASURES

Human studies evaluating the effects of post-TBI anticoagulation on venous thromboembolism, hemorrhage, mortality, or coagulation parameters with original analyses were eligible for the review. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline was followed throughout the conduct of the review.

RESULTS

Thirty-nine eligible studies were identified from the literature, of which 23 studies with complete information on post-TBI anticoagulant use and patient outcomes were summarized in this review. Meta-analysis was unwarranted because of varying methodological design and quality of the studies. Twenty-one studies focused on the effects of pharmacological thromboprophylaxis (PTP) post-TBI on venous thromboembolism and/or progression of intracranial hemorrhage, whereas 2 randomized controlled trials analyzed coagulation parameters as the result of anticoagulation.

CONCLUSION

Pharmacological thromboprophylaxis appears to be safe among TBI patients with stabilized hemorrhagic patterns. More evidence is needed regarding effectiveness of PTP in preventing venous thromboembolism as well as preferred agent, dose, and timing for PTP.

The Formation of Microthrombi in Parenchymal Microvessels after Traumatic Brain Injury Is Independent of Coagulation Factor XI

Microthrombus formation and bleeding worsen the outcome after traumatic brain injury (TBI). The aim of the current study was to characterize these processes in the brain parenchyma after experimental TBI and to determine the involvement of coagulation factor XI (FXI). C57BL/6 mice (n = 101) and FXI-deficient mice (n = 15) were subjected to controlled cortical impact (CCI). Wild-type mice received an inhibitory antibody against FXI (14E11) or control immunoglobulin G 24 h before or 30 or 120 min after CCI. Cerebral microcirculation was visualized in vivo by 2-photon microscopy 2-3 h post-trauma and histopathological outcome was assessed after 24 h. TBI induced hemorrhage and microthrombus formation in the brain parenchyma (p < 0.001). Inhibition of FXI activation or FXI deficiency did not reduce cerebral thrombogenesis, lesion volume, or hemispheric swelling. However, it also did not increase intracranial hemorrhage. Formation of microthrombosis in the brain parenchyma after TBI is independent of the intrinsic coagulation cascade since it was not reduced by inhibition of FXI. However, since targeting FXI has well-established antithrombotic effects in humans and experimental animals, inhibition of FXI could represent a reasonable strategy for the prevention of deep venous thrombosis in immobilized patients with TBI.

Thromboelastography defines late hypercoagulability after TBI: a pilot study

INTRODUCTION

Traumatic brain injury (TBI) is associated with a hypercoagulable state, the mechanism and duration of which remain unclear. We sought to determine whether thromboelastography (TEG) analysis could identify the hypercoagulable state after TBI, as defined by elevations in maximal amplitude (MA), thrombus generation (TG), G value (G), and alpha angle (αA).

METHODS

Patients with moderate-severe TBI, defined primarily as a GCS <12, admitted between 1/2012 and 8/2013 were eligible for enrolment in this prospective cohort study. TEG profiles were obtained between 0-24 h (T1), 24-48 h (T2), 48-72 h (T3), 72-96 h (T4), and 96-120 h (T5) after admission. Early TEG was defined as 0-48 h, and late TEG was defined as >48 h.

RESULTS

Twenty five patients (80 % men) and 7 age- and sex-matched control subjects were studied. Median age was 38 years (range 18-85). Early MA was [63.6 mm (60.5, 67.4)] versus late MA [69.9 mm (65.2,73.9); p = 0.02], early TG was [763.3 mm/min (712.8, 816.2)] versus late TG [835.9 mm/min (791.2,888.3); p = 0.02], and early G was [8.8 d/cm(2) (7.7,10.4)] versus late G [11.6 d/cm(2) (9.4,14.1); p = 0.02]. Study patients had higher MA (p = 0.02), TG (p = 0.03), and G (p = 0.02) values at T5 compared to controls. There was a linear increase per day of MA by 2.6 mm (p = 0.001), TG 31.9 mm/min (p ≤ 0.001), and G value by 1.3 d/cm(2) (p ≤ 0.001) when clustered by pairs in regression analysis. Lower MA values trended toward home discharge (p = 0.08).

CONCLUSION

The data suggest a progressive and delayed hypercoagulable state observed days after initial TBI. The hypercoagulable state may reflect excess platelet activity.

Timing for deep vein thrombosis chemoprophylaxis in traumatic brain injury: an evidence-based review

Multiple studies have addressed deep vein thrombosis chemoprophylaxis timing in traumatic brain injuries. However, a precise time for safe and effective chemoprophylaxis is uncertain according to experts. A comprehensive literature review on brain injuries was performed to delineate temporal proportions for 1) spontaneous intracranial hemorrhage (ICH) progression, 2) post-chemoprophylaxis ICH expansion, and 3) post-chemoprophylaxis deep vein thrombosis. Twenty-three publications were found including more than 5,000 patients. Spontaneous ICH expansion at 24 hours was 14.8% in 1,437 patients from chemoprophylaxis studies and 29.9% in 1,257 patients not in chemoprophylaxis studies (P < 0.0001). With low-risk ICH (n = 136), 99% of spontaneous ICH expansion occurred within 48 hours. In moderate or high-risk ICH (n = 109), 18% of spontaneous ICH expansion occurred after day 3. If patients with pre-chemoprophylaxis ICH expansion are included, the post-chemoprophylaxis ICH expansion proportion was 5.6% in 1,258 patients with chemoprophylaxis on days 1 to 3 and was 1.5% in 401 with chemoprophylaxis after day 3 (P = 0.0116). If patients with pre-chemoprophylaxis ICH expansion were excluded, the post-chemoprophylaxis ICH expansion proportion was 3.1% in 1,570 patients with chemoprophylaxis on days 1 to 3 and was 2.8% in 582 with chemoprophylaxis after day 3 (P = 0.7769). In diffuse axonal injury (n = 188), the post-chemoprophylaxis ICH expansion proportion was 1.6% with chemoprophylaxis after day 3. The deep vein thrombosis proportions were as follows: chemoprophylaxis on days 1 to 3, 2.6% in 2,384 patients; chemoprophylaxis on days 4 or 5, 2.2% in 831; and chemoprophylaxis on day 8, 14.1% in 99 (P < 0.0001). Spontaneous ICH expansion proportions at 24 hours substantially vary between chemoprophylaxis and non-chemoprophylaxis studies. Chemoprophylaxis should not be given within 3 days of injury for moderate-risk or high-risk ICH. Chemoprophylaxis is reasonable when low-risk patients have not developed ICH expansion within 48 hours post-injury. Chemoprophylaxis is also acceptable after day 3, when low-risk patients develop ICH expansion within 48 hours post-injury. In diffuse axonal injury patients who have not developed ICH within 72 hours, chemoprophylaxis is reasonable. Deep vein thrombosis proportions significantly increase when chemoprophylaxis is withheld for greater than 7 days.

Late Venous Thromboembolism Prophylaxis after Craniotomy in Acute Traumatic Brain Injury

The objective of this study is to compare rates of venous thromboembolism (VTE) in patients who receive enoxaparin prophylaxis compared with no enoxaparin prophylaxis after craniotomy for traumatic brain injury (TBI). This retrospective cohort evaluated all trauma patients admitted to a Level I trauma center from January 2006 to December 2011 who received craniotomy after acute TBI. Patients were excluded if developed VTE before administration of enoxaparin or they died within the first 72 hours of hospital admission. A total of 271 patients were included (enoxaparin prophylaxis, n = 45; no enoxaparin prophylaxis, n = 225). The median time until enoxaparin initiation was 11 ± 1 days. There was no significant difference in the proportion of patients who developed a VTE when using enoxaparin prophylaxis compared with no enoxaparin prophylaxis (2 vs 4%; P = 0.65). Rates of deep vein thrombosis (2 vs 3%; P = 0.87) and pulmonary embolism (0 vs 1%; P = 0.99) were similar between treatment groups, respectively. Late enoxaparin prophylaxis did not demonstrate a protective effect for VTE. Given the overall low event rate, the administration of pharmacologic prophylaxis against VTE late in the treatment course may not be routinely warranted after craniotomy for acute TBI. Further investigation with early administration of enoxaparin is needed.

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.

The Parkland Protocol's modified Berne-Norwood criteria predict two tiers of risk for traumatic brain injury progression

As a basis for venous thromboembolism (VTE) prophylaxis after traumatic brain injury (TBI), we have previously published an algorithm known as the Parkland Protocol. Patients are classified by risk for spontaneous progression of hemorrhage with chemoprophylaxis regimens tailored to each tier. We sought to validate this schema. In our algorithm, patients with any of the following are classified "low risk" for spontaneous progression: subdural hemorrhage ≤8 mm thick; epidural hemorrhage ≤8 mm thick; contusions ≤20 mm in diameter; a single contusion per lobe; any amount of subarachnoid hemorrhage; or any amount of intraventricular hemorrhage. Patients with any injury exceeding these are "moderate risk" for progression, and any patient receiving a monitor or craniotomy is "high risk." From February 2010 to November 2012, TBI patients were entered into a dedicated database tracking injury types and sizes, risk category at presentation, and progression on subsequent computed tomgraphies (CTs). The cohort (n=414) was classified as low risk (n=200), moderate risk (n=75), or high risk (n=139) after first CT. After repeat CT scan, radiographic progression was noted in 27% of low-risk, 53% of moderate-risk, and 58% of high-risk subjects. Omnibus analysis of variance test for differences in progression rates was highly significant (p<0.0001). Tukey's post-hoc test showed the low-risk progression rate to be significantly different than both the moderate- and high-risk arms; no difference was noted between the moderate- and high-risk arms themselves. These criteria are a valid tool for classifying TBI patients into two categories of risk for spontaneous progression. This supports tailored chemoprophylaxis regimens for each arm.

Benefits and risks of anticoagulation resumption following traumatic brain injury

IMPORTANCE

The increased risk of hemorrhage associated with anticoagulant therapy following traumatic brain injury creates a serious dilemma for medical management of older patients: Should anticoagulant therapy be resumed after traumatic brain injury, and if so, when?

OBJECTIVE

To estimate the risk of thrombotic and hemorrhagic events associated with warfarin therapy resumption following traumatic brain injury.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of administrative claims data for Medicare beneficiaries aged at least 65 years hospitalized for traumatic brain injury during 2006 through 2009 who received warfarin in the month prior to injury (n = 10,782).

INTERVENTION

Warfarin use in each 30-day period following discharge after hospitalization for traumatic brain injury.

MAIN OUTCOMES AND MEASURES

The primary outcomes were hemorrhagic and thrombotic events following discharge after hospitalization for traumatic brain injury. Hemorrhagic events were defined on inpatient claims using International Classification of Diseases, Ninth Revision, Clinical Modification codes and included hemorrhagic stroke, upper gastrointestinal bleeding, adrenal hemorrhage, and other hemorrhage. Thrombotic events included ischemic stroke, pulmonary embolism, deep venous thrombosis, and myocardial infarction. A composite of hemorrhagic or ischemic stroke was a secondary outcome.

RESULTS

Medicare beneficiaries with traumatic brain injury were predominantly female (64%) and white (92%), with a mean (SD) age of 81.3 (7.3) years, and 82% had atrial fibrillation. Over the 12 months following hospital discharge, 55% received warfarin during 1 or more 30-day periods. We examined the lagged effect of warfarin use on outcomes in the following period. Warfarin use in the prior period was associated with decreased risk of thrombotic events (relative risk [RR], 0.77 [95% CI, 0.67-0.88]) and increased risk of hemorrhagic events (RR, 1.51 [95% CI, 1.29-1.78]). Warfarin use in the prior period was associated with decreased risk of hemorrhagic or ischemic stroke (RR, 0.83 [95% CI, 0.72-0.96]).

CONCLUSIONS AND RELEVANCE

Results from this study suggest that despite increased risk of hemorrhage, there is a net benefit for most patients receiving anticoagulation therapy, in terms of a reduction in risk of stroke, from warfarin therapy resumption following discharge after hospitalization for traumatic brain injury.

Venous thromboembolism prophylaxis in patients with traumatic brain injury

Traumatic brain injury (TBI) with associated intracranial hemorrhage (ICH) occurs frequently in trauma. Trauma patients are also at high risk of developing venous thromboembolic (VTE) complications. Low Molecular Weight Heparin (LMWH) is used in trauma patients as prophylaxis to reduce the risk of VTE events. It remains unclear, however, if LMWH is safe to use in trauma patients with ICH for fear of hematoma progression. The "Evidence-based telemedicine: trauma & acute care surgery (EBT-TACS)" Journal Club performed a critical appraisal of 3 recent and most relevant studies on timing to initiate, safety and use of LMWH in trauma patients with ICH. Specifically, we appraised a i) critical literature review on the topic, ii) a multicenter, retrospective cohort study assessing the safety of LMWH in trauma patients with ICH and iii) a randomized, pilot study assessing the feasibility and event rates of ICH progression, laying the groundwork for future randomized controlled trials (RCT) on the topic. Some results are conflicting, with the highest level of evidence being the pilot RCT demonstrating the safety for early use of LMWH in TBI with ICH. Much of this research, however, was generated by a single center and consequently lacks external validity. Furthermore, clinical recommendations cannot be generated based on pilot studies. Evidence-based guidelines and recommendations could not be made at this time, until the completion of further studies on this challenging topic.