Safety and Efficacy of Early Pharmacological Thromboprophylaxis in Traumatic Brain Injury: Systematic Review and Meta-Analysis

Impact of early follow-up CT in the conservative management of traumatic brain injury on surgical decision making: A retrospective, single-center analysis with special respect to coagulopathy

INTRODUCTION

Initial management of traumatic brain injury (TBI) without immediate need for surgical therapy varies across centers. The additional value of routine repeat cranial computerized tomography (CT) to neurological monitoring is controversial. This retrospective study investigates the impact of routine follow-up CT after 6 h (CT6h) in initially conservatively managed TBI on surgical decision making. Furthermore, the impact of coagulopathy on lesion size and progression was examined.

METHODS

We reviewed charts of patients admitted to our clinic in the time between 1st January 2020 and 30th June 2022 for the ICD10 diagnosis S06.3 (traumatic brain contusion), S06.4 (epidural hematoma), S06.5 (subdural hematoma), and S06.6 (traumatic subarachnoid hemorrhage). Baseline characteristics as well as timing, reason, and consequences of first and second cranial CT, clinical course, lesion size at first and second CT as well as presence and type of coagulopathy (standard laboratory testing and prior medical history) were noted among others. Significance testing was carried out using Student's t-test. The significance level was set to p < 0.005.

RESULTS

A total of 213 patients were included, 78 were operated after first CT, 123 underwent clinical and imaging surveillance, and 12 patients were not treated. CT6h did not anticipate imminent neurological deterioration. Early secondary deteriorating patients (9/123, 7.3%) did so before 6 h after admission clustering between 3 and 4 h (6/9, 66.7%). CT6h changed surgical decision making in one case (1/114, < 1%). Nine out of 106 (8.5%) patients managed conservatively after CT6h showed a late secondary clinical deterioration or failure of conservative treatment, eight out of which had stable size of hemorrhage in CT6h. There was no significant difference in lesion size at first CT related to the presence of coagulopathy, antiplatelet agents, or anticoagulant drugs for SDH or contusions. In patients with radiological progression of SDH in combined brain injury (CBI), coagulopathy was associated with a higher increase of lesion size (diameter increase > 6 mm: 11.1% with vs. 2.8% without coagulopathy). This effect was not observed for contusions in CBI (volume increase > 6 ml: 17.4% with vs. 22.7% without coagulopathy).

CONCLUSION

Early routine follow-up CT does neither anticipate imminent neurological deterioration nor impact surgical decision making. A substantial number of patients with initially stable follow-up imaging need delayed surgery due to conservative treatment failure. If patients can be monitored clinically, surgical decision making depends on clinical status. Patients with coagulopathy do not present with larger lesions, but show a higher ratio of drastic increase in SDH in contrast to contusions.

Venous thromboembolism chemoprophylaxis in geriatric trauma patients with isolated severe traumatic brain injury

PURPOSE

Low-molecular-weight-heparin (LMWH) has been shown to be associated with a decreased risk of venous thromboembolism (VTE) and mortality compared to unfractionated heparin (UH) in severe traumatic brain injury (TBI). The aim of this study was to see if this association persists among a subset of patients, namely elderly patients with isolated TBI.

METHODS

This Trauma Quality Improvement Project (TQIP) database study included patients ≥ 65 years old with severe TBI (Abbreviated injury score [AIS] ≥ 3) that received either LMWH or UH for VTE prophylaxis. Patients with associated severe injuries (extracranial AIS ≥ 3), transferals, deaths < 72-h, hospitalization < 2 days, VTE chemoprophylaxis other than UH or LMWH, or with a history of bleeding diathesis were excluded. The association between VTE, deep vein thrombosis (DVT), and pulmonary embolism (PE) with VTE chemoprophylaxis was analyzed with multivariable analysis, subset analyses of different grades of AIS-head injury, and a 1:1 matched LWMH:UH cohort of patients.

RESULTS

Out of 14,926 patients, 11,036 (73.9%) received LMWH. Multivariate analysis showed that patients receiving LMWH had a decreased risk of mortality (OR 0.81, 95% CI 0.67-0.97, p < 0.001) but a similar risk of VTE (OR 0.83, 95% CI 0.63-1.08). Analysis according to head-AIS showed that LMWH was associated with a decreased risk of PE in patients AIS-3 but not in AIS 4 or 5. In a 1:1 matched cohort of LMWH:UH patients, the risk of PE, DVT and VTE were all similar but LMWH continued to be associated with a decreased risk of mortality (OR 0.81, CI 0.67-0.97, p = 0.023).

CONCLUSION

LMWH was associated with a decreased risk of overall mortality and reduced risk of PE compared to UH among geriatric patients with a severe head injury.

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.

Efficacy and Safety of Low Molecular Weight Heparin Versus Unfractionated Heparin for Prevention of Venous Thromboembolism in Trauma Patients: A Systematic Review and Meta-analysis

PURPOSE

Trauma patients are at high risk of VTE. We summarize the efficacy and safety of LMWH versus UFH for the prevention of VTE in trauma patients.

METHODS

We searched 6 databases from inception through March 12, 2021. We included randomized controlled trials (RCTs) or observational studies comparing LMWH versus UFH for thromboprophylaxis in adult trauma patients. We pooled effect estimates across RCTs and observational studies separately, using random-effects model and inverse variance weighting. We assessed risk of bias using the Cochrane tool for RCTs and the Risk of Bias in Non-Randomized Studies (ROBINS)-I tool for observational studies and assessed certainty of findings using Grading of Recommendations, Assessment, Development and Evaluations methodology.

RESULTS

We included 4 RCTs (879 patients) and 8 observational studies (306,747 patients). Based on pooled RCT data, compared to UFH, LMWH reduces deep vein thrombosis (RR 0.67, 95% CI 0.50 to 0.88, moderate certainty) and VTE (RR 0.68, 95% CI 0.51 to 0.90, moderate certainty). As compared to UFH, LMWH may reduce pulmonary embolism [adjusted odds ratio from pooled observational studies 0.56 (95% CI 0.50 to 0.62)] and mortality (adjusted odds ratio from pooled observational studies 0.54, 95% CI 0.45 to 0.65), though based on low certainty evidence. There was an uncertain effect on adverse events (RR from pooled RCTs 0.80, 95% CI 0.48 to 1.33, very low certainty) and heparin induced thrombocytopenia [RR from pooled RCTs 0.26 (95% CI 0.03 to 2.38, very low certainty)].

CONCLUSIONS

Among adult trauma patients, LMWH is superior to UFH for deep vein thrombosis and VTE prevention and may additionally reduce pulmonary embolism and mortality. The impact on adverse events and heparin induced thrombocytopenia is uncertain.

Characterizing the delays in adequate thromboprophylaxis after TBI

Background

We sought to compare enoxaparin dosing for venous thromboembolism (VTE) prophylaxis in trauma patients with and without traumatic brain injury (TBI) to better understand the time and dose required to reach target anti-Xa levels. Our hypothesis was that patients with TBI have significant delays in the initiation of adequate pharmacological prophylaxis and require a higher enoxaparin dose than currently recommended.

Methods

The medical records of trauma patients who received enoxaparin dosing based on anti-Xa trough levels between August 2014 and October 2016 were reviewed. Patients were included if their anti-Xa trough level reached the target range (0.1 IU/mL to 0.2 IU/mL).

Results

A total of 163 patients had anti-Xa levels within the target range of which 41 (25.2%) had TBI. Patients with TBI had longer delays before initiating enoxaparin (7.5 days vs. 1.5 days after admission, p<0.01) and were more likely to receive unfractionated heparin prior to enoxaparin (46.3% vs. 11.5%, p<0.01). Anti-Xa levels reached the target range later in patients with TBI (11 days vs. 5 days after admission, p<0.01). Enoxaparin 40 mg two times per day was the median dose required to reach the target anti-Xa levels for both cohorts. VTE rates were higher among patients with TBI (22.0% vs. 9.0%, p=0.03). Four patients (9.8%) had progression of their intracranial hemorrhage prior to receiving enoxaparin, although none progressed during enoxaparin administration.

Conclusion

Among patients with TBI who reached target anti-Xa levels, 11 days after admission were required to reach a median enoxaparin dose of 40 mg two times per day. Unfractionated heparin was used as pharmacological prophylaxis in about half of these patients. The delay in reaching the target anti-Xa levels and the use of unfractionated heparin likely contribute to the higher VTE rate in patients with TBI.

Level of evidence

Level III, therapeutic.

Early Chemoprophylaxis Against Venous Thromboembolism in Patients With Traumatic Brain Injury

INTRODUCTION

Timing to start of chemoprophylaxis for venous thromboembolism (VTE) in patients with traumatic brain injury (TBI) remains controversial. We hypothesize that early administration is not associated with increased intracranial hemorrhage.

METHODS

A retrospective study of adult patients with TBI following blunt injury was performed. Patients with penetrating brain injury, any moderate/severe organ injury other than the brain, need for craniotomy/craniectomy, death within 24 hours of admission, or progression of bleed on 6 hour follow-up head computed tomography scan were excluded. Patients were divided into early (≤24 hours) and late (>24 hours) cohorts based on time to initiation of chemoprophylaxis. Progression of bleed was the primary outcome.

RESULTS

264 patients were enrolled, 40% of whom were in the early cohort. The average time to VTE prophylaxis initiation was 17 hours and 47 hours in the early and late groups, respectively (P < .0001). There was no difference in progression of bleed (5.6% vs. 7%, P = .67), craniectomy/-craniotomy rate (1.9% vs. 2.5%, P = .81), or VTE rate (0% vs. 2.5%, P = .1).

CONCLUSION

Early chemoprophylaxis is not associated with progression of hemorrhage or need for neurosurgical intervention in patients with TBI and a stable head CT 7 hours following injury.

Intracranial pressure monitors associated with increased venous thromboembolism in severe traumatic brain injury

Background

Utilization of intracranial pressure monitors (ICPMs) has not been consistently shown to improve mortality in patients with severe traumatic brain injury (TBI). A single-center analysis concluded that venous thromboembolism (VTE) chemoprophylaxis (CP) posed no significant bleeding risk in patients following ICPM implementation; however, there is still debate about the optimal use and timing of CP in patients with ICPMs for fear of worsening intracranial hemorrhage. We hypothesized that ICPM use is associated with increased time to VTE CP and thus increased VTE in patients with severe TBI.

Methods

A retrospective analysis of the Trauma Quality Improvement Program (2010–2016) was performed to compare severe TBI patients with and without ICPMs. A multivariable logistic regression analysis was completed.

Results

From 35,673 patients with severe TBI, 12,487 (35%) had an ICPM. Those with ICPMs had a higher rate of VTE CP (64.3% vs. 49.4%, p < 0.001) but a longer median time to CP initiation (5 vs. 4 days, p < 0.001) as well as a longer hospital length of stay (LOS) (18 vs. 9 days, p < 0.001) compared to those without ICPMs. After adjusting for covariates, ICPM use was found to be associated with a higher risk of VTE (9.2% vs 4.3%, OR = 1.75, CI = 1.42–2.15, p < 0.001).

Conclusions

Compared to patients without ICPMs, those with ICPMs had a longer delay to initiation of CP leading to an increase in VTE. In addition, there was a nearly two-fold higher associated risk for VTE in patients with ICPMs even when controlling for known VTE risk factors. Improved adherence to initiation of CP in the setting of ICPMs may help decrease the associated risk of VTE with ICPMs.

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.

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.

Evaluation of Appropriate Venous Thromboembolism Prophylaxis in Patients With Orthopaedic Trauma With Symptom-Driven Vascular and Radiographic Studies

OBJECTIVE

To evaluate venous thromboembolism (VTE) prophylaxis adherence and effectiveness in orthopaedic trauma patients who had vascular or radiographic studies showing deep vein thromboses or pulmonary emboli.

DESIGN

Retrospective review.

SETTING

A level I trauma center that independently services a 5-state region.

PATIENTS

Four hundred seventy-six patients with orthopaedic trauma who underwent operative treatments for orthopaedic injuries and had symptom-driven diagnostic VTE studies.

INTERVENTION

The medical records of patients treated surgically between July 2010 and March 2013 were interrogated using a technical tool that electronically captures thrombotic event data from vascular and radiologic imaging studies by natural language processing.

MAIN OUTCOME MEASUREMENTS

Patients were evaluated for hospital guideline-directed VTE prophylaxis adherence with mechanical or chemical prophylaxis. Patient demographics, associated injuries, mechanism of injury, and symptoms that led to imaging for a VTE were also assessed.

RESULTS

Of the 476 orthopaedic patients who met inclusion criteria, 100 (mean age 52.3 median 52, SD 18.3, 70% men) had positive VTE studies. Three hundred seventy-six (age 47.3, SD 17.3, 69% men) had negative VTE studies. Of the 100 patients with VTE, 63 deep vein thromboses, and 49 pulmonary emboli were found. Eight-five percent of all patients met hospital guideline-VTE prophylaxis standards.

CONCLUSION

The study population had better than previously reported VTE prophylaxis adherence, however, patients still developed VTEs.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

Evaluating the Role of Reduced Oxygen Saturation and Vascular Damage in Traumatic Brain Injury Using Magnetic Resonance Perfusion-Weighted Imaging and Susceptibility-Weighted Imaging and Mapping

The cerebral vasculature, along with neurons and axons, is vulnerable to biomechanical insult during traumatic brain injury (TBI). Trauma-induced vascular injury is still an underinvestigated area in TBI research. Cerebral blood flow and metabolism could be important future treatment targets in neural critical care. Magnetic resonance imaging offers a number of key methods to probe vascular injury and its relationship with traumatic hemorrhage, perfusion deficits, venous blood oxygen saturation changes, and resultant tissue damage. They make it possible to image the hemodynamics of the brain, monitor regional damage, and potentially show changes induced in the brain's function not only acutely but also longitudinally following treatment. These methods have recently been used to show that even mild TBI (mTBI) subjects can have vascular abnormalities, and thus they provide a major step forward in better diagnosing mTBI patients.

Early initiation of prophylactic heparin in severe traumatic brain injury is associated with accelerated improvement on brain imaging

Background:

Venous thromboembolic prophylaxis (VTEp) is often delayed following traumatic brain injury (TBI), yet animal data suggest that it may reduce cerebral inflammation and improve cognitive recovery. We hypothesized that earlier VTEp initiation in severe TBI patients would result in more rapid neurologic recovery and reduced progression of brain injury on radiologic imaging.

Study Design:

Medical charts of severe TBI patients admitted to a level 1 trauma center in 2009-2010 were queried for admission Glasgow Coma Scale (GCS), head Abbreviated Injury Scale, Injury Severity Score (ISS), osmotherapy use, emergency neurosurgery, and delay to VTEp initiation. Progression (+1 = better, 0 = no change, −1 = worse) of brain injury on head CTs and neurologic exam (by bedside MD, nurse) was collected from patient charts. Head CT scan Marshall scores were calculated from the initial head CT results.

Results:

A total of 22, 34, and 19 patients received VTEp at early (<3 days), intermediate (3-5 days), and late (>5 days) time intervals, respectively. Clinical and radiologic brain injury characteristics on admission were similar among the three groups (P > 0.05), but ISS was greatest in the early group (P < 0.05). Initial head CT Marshall scores were similar in early and late groups. The slowest progression of brain injury on repeated head CT scans was in the early VTEp group up to 10 days after admission.

Conclusion:

Early initiation of prophylactic heparin in severe TBI is not associated with deterioration neurologic exam and may result in less progression of injury on brain imaging. Possible neuroprotective effects of heparin in humans need further investigation.