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

Severe Traumatic Brain Injury and Pulmonary Embolism: Risks, Prevention, Diagnosis and Management

Severe traumatic brain injury (sTBI) is a silent epidemic, causing approximately 300,000 intensive care unit (ICU) admissions annually, with a 30% mortality rate. Despite worldwide efforts to optimize the management of patients and improve outcomes, the level of evidence for the treatment of these patients remains low. The concomitant occurrence of thromboembolic events, particularly pulmonary embolism (PE), remains a challenge for intensivists due to the risks of anticoagulation to the injured brain. We performed a literature review on sTBI and concomitant PE to identify and report the most recent advances on this topic. We searched PubMed and Scopus for papers published in the last five years that included the terms "pulmonary embolism" and "traumatic brain injury" in their title or abstract. Exclusion criteria were papers referring to children, non-sTBI populations, and post-acute care. Our search revealed 75 papers, of which 38 are included in this review. The main topics covered include the prevalence of and risk factors for pulmonary embolism, the challenges of timely diagnosis in the ICU, the timing of pharmacological prophylaxis, and the treatment of diagnosed PE.

Prevalence and Risk Factors of Deep Venous Thrombosis in Intensive Inpatient Neurorehabilitation Unit

Venous thromboembolism (VTE) (deep vein thrombosis and its complication, pulmonary embolism) is a major cause of morbidity and mortality in hospitalized patients and about 7% of these cases are due to immobility secondary to a neurological impairment. Acquired brain injury (ABI) has also been recognized as one of the main risk factors for VTE. Numerous epidemiological studies have been conducted to assess the risk factors for VTE in institutionalized polytrauma patients, although there is a lack of information about neurorehabilitation wards. Since VTE is often undiagnosed, this prospective study aimed to determine the prevalence and clinical characteristics of lower-limb deep venous thrombosis (DVT) in ABI patients at neurorehabilitation admission.

METHODS

ABI patients were screened for DVT on admission to the intensive rehabilitation unit (IRU) with compression ultrasonography and basal D-dimer assay and were daily clinically monitored until discharge. A total of 127 consecutive ABI patients (mean age: 60.1 ± 17.6 years; 63% male; time from event: 30.9 ± 22.1 days; rehabilitation time in IRU: 84.6 ± 58.4 days) were enrolled.

RESULTS

On admission to the IRU, the DVT prevalence was about 8.6%. The mean D-dimer level in patients with DVT was significantly higher than in patients without DVT (6 ± 0.9 vs. 1.97 ± 1.61, p-value = 0.0001). ABI patients with DVT did not show any significant clinical characteristics with respect to ABI without DVT, although a prevalence of hemorrhagic strokes and patients originating from the Intensive Care Unit and Neurosurgery ward was revealed. During the rehabilitation period, patients with DVT showed a significant difference in pharmacological DVT prophylaxis (high prevalence of nadroparin with 27.3% vs. 1.7%, p-value = 0.04) and a prevalence of transfers in critical awards (36% versus 9.5% of patients without DVT, p-value = 0.05). The mortality rate was similar in the two groups.

CONCLUSIONS

Our research offers a more comprehensive view of the clinical development of DVT patients and confirms the prevalence rate of DVT in ABI patients as determined upon IRU admission. According to our findings, screening these individuals regularly at the time of rehabilitation admission may help identify asymptomatic DVT quickly and initiate the proper treatment to avoid potentially fatal consequences. However, to avoid time-consuming general ultrasonography observation, a more precise selection of patients entering the rehabilitation ward is required.

Venous Thrombus Embolism in Polytrauma: Special Attention to Patients with Traumatic Brain Injury

Venous thrombus embolism (VTE) is common after polytrauma, both of which are considered significant contributors to poor outcomes and mortality. Traumatic brain injury (TBI) is recognized as an independent risk factor for VTE and one of the most common components of polytraumatic injuries. Few studies have assessed the impact of TBI on the development of VTE in polytrauma patients. This study sought to determine whether TBI further increases the risk for VTE in polytrauma patients. A retrospective, multi-center trial was performed from May 2020 to December 2021. The occurrence of venous thrombosis and pulmonary embolism from injury to 28 days after injury was observed. Of 847 enrolled patients, 220 (26%) developed DVT. The incidence of DVT was 31.9% (122/383) in patients with polytrauma with TBI (PT + TBI group), 22.0% (54/246) in patients with polytrauma without TBI (PT group), and 20.2% (44/218) in patients with isolated TBI (TBI group). Despite similar Glasgow Coma Scale scores, the incidence of DVT in the PT + TBI group was significantly higher than in the TBI group (31.9% vs. 20.2%, p < 0.01). Similarly, despite no difference in Injury Severity Scores between the PT + TBI and PT groups, the DVT rate was significantly higher in the PT + TBI group than in the PT group (31.9% vs. 22.0%, p < 0.01). Delayed anticoagulant therapy, delayed mechanical prophylaxis, older age, and higher D-dimer levels were independent predictive risk factors for DVT occurrence in the PT + TBI group. The incidence of PE within the whole population was 6.9% (59/847). Most patients with PE were in the PT + TBI group (64.4%, 38/59), and the PE rate was significantly higher in the PT + TBI group compared to the PT (p < 0.01) or TBI (p < 0.05) group. In conclusion, this study characterizes polytrauma patients at high risk for VTE occurrence and emphasizes that TBI markedly increases the incidence of DVT and PE in polytrauma patients. Delayed anticoagulant therapy and delayed mechanical prophylaxis were identified as the major risk factors for a higher incidence of VTE in polytrauma patients with TBI.

Prevalence of Venous Thromboembolism in Intensive Care Units: A Meta-Analysis

OBJECTIVE

Venous thromboembolism (VTE) is a life threating complication in intensive care units (ICUs). This study aimed to pool the prevalence of VTE and examined the risk factors of VTE in intensive care patients worldwide.

METHODS

A systematic search in PubMed, EMBASE and Web of Science databases was performed. Studies reported that the data on the prevalence of VTE or relevant information were synthesized using a random-effects model.

RESULTS

A total of 42 studies reporting on 27,344 patients were included. The pooled prevalence of VTE was 10.0% (95% CI: 7.0-14.0%). Subgroup and metaregression analyses found that thromboprophylaxis strategy, simplified acute physiology score (SAPS II), age, study quality, sample size, malignancy, sex, spinal cord injury and injury severity score (ISS) moderated the prevalence of VTE in intensive care patients.

CONCLUSIONS

The present meta-analysis revealed a high prevalence of VTE in critically ill patients. The risk factors of VTE included thromboprophylaxis strategy, SAPS II, age, malignancy, sex, spinal cord injury and ISS. Therefore, we need to pay more attention to high-risk populations of VTE in intensive care patients.

Trauma-induced pulmonary thromboembolism: What's update?

Trauma-induced pulmonary thromboembolism is the second leading cause of death in severe trauma patients. Primary fibrinolytic hyperactivity combined with hemorrhage and consequential hypercoagulability in severe trauma patients create a huge challenge for clinicians. It is crucial to ensure a safe anticoagulant therapy for trauma patients, but a series of clinical issues need to be answered first, for example, what are the risk factors for traumatic venous thromboembolism? How to assess and determine the status of coagulation dysfunction of patients? When is the optimal timing to initiate pharmacologic prophylaxis for venous thromboembolism? What types of prophylactic agents should be used? How to manage the anticoagulation-related hemorrhage and to determine the optimal timing of restarting chemoprophylaxis? The present review attempts to answer the above questions.

Viscoelastic Testing and Coagulopathy of Traumatic Brain Injury

A unique coagulopathy often manifests following traumatic brain injury, leading the clinician down a difficult decision path on appropriate prophylaxis and therapy. Conventional coagulation assays—such as prothrombin time, partial thromboplastin time, and international normalized ratio—have historically been utilized to assess hemostasis and guide treatment following traumatic brain injury. However, these plasma-based assays alone often lack the sensitivity to diagnose and adequately treat coagulopathy associated with traumatic brain injury. Here, we review the whole blood coagulation assays termed viscoelastic tests and their use in traumatic brain injury. Modified viscoelastic tests with platelet function assays have helped elucidate the underlying pathophysiology and guide clinical decisions in a goal-directed fashion. Platelet dysfunction appears to underlie most coagulopathies in this patient population, particularly at the adenosine diphosphate and/or arachidonic acid receptors. Future research will focus not only on the utility of viscoelastic tests in diagnosing coagulopathy in traumatic brain injury, but also on better defining the use of these tests as evidence-based and/or precision-based tools to improve patient outcomes.

Use of Thromboelastography in the Evaluation and Management of Patients With Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Supplemental Digital Content is available in the text.

Traumatic brain injury is associated with coagulopathy that increases mortality risk. Viscoelastic hemostatic assays such as thromboelastography (Haemonetics SA, Signy, Switzerland) provide rapid coagulopathy assessment and may be particularly useful for goal-directed treatment of traumatic brain injury patients. We conducted a systematic review to assess thromboelastography in the evaluation and management of coagulopathy in traumatic brain injury patients.

Thromboembolic complications among multiple injured patients with pelvic injuries: identifying risk factors for possible patient-tailored prophylaxis

Background

Patients with pelvic and/or acetabular fractures are at high risk of developing thromboembolic (TE) complications. In our study we investigate TE complications and the potential negative effects of concomitant pelvic or acetabular injuries in multiple injured patients according to pelvic/acetabular injury severity and fracture classification.

Methods

The TraumaRegister DGU® was analyzed between 2010 and 2019. Multiple injured patients with pelvic and/or acetabular fractures with ISS ≥ 16 suffering from TE complications were identified. We conducted a univariate and multivariate analysis with TE events as independent variable to examine potential risk factors and contributing factors.

Results

10.634 patients met our inclusion criteria. The overall TE incidence was 4.9%. Independent risk factors for the development of TE complications were sepsis, ≥ 10 operative interventions, mass transfusion (≥ 10 PRBCs), age ≥ 65 years and AIS_Abdomen ≥ 3 (all p < 0.001). No correlation was found for overall injury severity (ISS), moderate traumatic brain injury, additional injury to lower extremities, type B and C pelvic fracture according to Tile/AO/OTA and closed or open acetabular fracture.

Conclusions

Multiple injured patients suffering from pelvic and/or acetabular fractures are at high risk of developing thromboembolic complications. Independent risk factors for the development of thromboembolic events in our study cohort were age ≥ 65 years, mass transfusion, AIS_Abdomen ≥ 3, sepsis and ≥ 10 surgery procedures. Among multiple injured patients with acetabular or pelvic injuries the severity of these injuries seems to have no further impact on thromboembolic risk. Our study, however, highlights the major impact of early hemorrhage and septic complications on thromboembolic risk in severely injured trauma patients. This may lead to individualized screening examinations and a patient-tailored thromboprophylaxis in high-risk patients for TE. Furthermore, the number of surgical interventions should be minimized in these patients to reduce thromboembolic risk.

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.

Chemoprophylaxis and Venous Thromboembolism in Traumatic Brain Injury at Different Trauma Centers

Patients with severe traumatic brain injury (TBI) are at an increased risk of venous thromboembolism (VTE). Because of concerns of worsening intracranial hemorrhage, clinicians are hesitant to start VTE chemoprophylaxis in this population. We hypothesized that ACS Level I trauma centers would be more aggressive with VTE chemoprophylaxis in adults with severe TBI than Level II centers. We also predicted that Level I centers would have a lower risk of VTE. We queried the Trauma Quality Improvement Program (2010–2016) database for patients with Abbreviated Injury Scale scores of 4 and 5 of the head and compared them based on treating the hospital trauma level. Of 204,895 patients with severe TBI, 143,818 (70.2%) were treated at Level I centers and 61,077 (29.8%) at Level II centers. The Level I cohort had a higher rate of VTE chemoprophylaxis use (43.2% vs 23.3%, P < 0.001) and a shorter median time to chemoprophylaxis (61.9 vs 85.9 hours, P < 0.001). Although Level I trauma centers started VTE chemoprophylaxis more often and earlier than Level II centers, there was no difference in the risk of VTE ( P = 0.414) after controlling for covariates. Future prospective studies are warranted to evaluate the timing, safety, and efficacy of early VTE chemoprophylaxis in severe TBI patients.

Elevated risk of venous thromboembolism among post-traumatic brain injury patients requiring pharmaceutical immobilization

Traumatic brain injury (TBI) patients are known to have a high rate of venous thromboembolism (VTE), and additional neuromuscular blockade or barbiturate coma therapy has the theoretical risk of exacerbating baseline hemostasis and elevating the incidence of thromboembolic events. We conducted a single-institution retrospective review of patients surviving severe TBI, as determined by need for intracranial pressure (ICP) monitoring, who further required paralytics or barbiturate therapy to maintain ICP control. Patients were administered VTE prophylaxis as clinically appropriate. Predictors for VTE were subsequently determined with univariate and logistic multivariate regression analyses. The main cohort includes 144 patients, 34 of whom received pharmaceutical immobilization for ICP control. Mean ISS and GCS at intake were 31.9 and 5.2, respectively. Among those receiving vs not-receiving paralytics and/or barbiturate therapy, there was a statistical difference of 12/34 (35.3%) vs 18/110 (16.4%, p = 0.0280) in VTE events, at a mean time greater than two weeks from the time of trauma. Multivariate logistics regression indicated 3.2 times increased odds of developing a VTE (log odds = 1.17, p = 0.023). No pediatric patients were positive for an event (0/12 vs 7/22, p = 0.0356), and infections were only documented among those with VTE (0/22 vs 4/12, p = 0.0107). Overall, paralytics and barbiturate therapy were correlated with a higher incidence of VTE among TBI patients. Although the need for ICP control will outweigh an increase in thromboembolic risk, there is value for increased surveillance and screening during the prolonged inpatient stay of these patients.

Analysis of venous thromboembolism in neurosurgical patients undergoing standard versus routine ultrasonography

Routine screening of high-risk asymptomatic trauma or surgical patients for venous thromboembolism (VTE) is controversial. Studies suggest against screening while others recognize that some patients at high risk may benefit. The purpose of this pilot study is to evaluate the benefit of routine screening using doppler ultrasonography for the early detection of deep venous thrombosis (DVT) in post-operative neurosurgical patients. This was a quasi-experimental study at a major academic tertiary care medical center. A total of 157 adults underwent cranial or spinal surgical interventions from March through August 2017 and received either standard screening (n = 104) versus routine ultrasonography screening (n = 53). There was no significant difference in incidence of DVT between the two groups: 11 (11%) in the standard screening group versus 5 (9%) in the routine screening group, p = 0.823. Upper and lower extremity ultrasonography was performed in 43 (41%) of the standard screening group versus 53 (100%) in the routine screening group, p < 0.001. DVT was identified in nearly one of every 6 ultrasonography screenings in the standard screening group versus 27 ultrasonography screenings required to identify one DVT in the routine screening group. There were the same number of screenings for upper extremity ultrasonography, but they did not yield or detect DVT; instead only superficial, untreatable, DVTs were reported. Total cost to diagnose one DVT, including screening and labor, averaged $13,664 in the standard group versus $56,525 in the routine group. Routine screening in neurosurgical patients who received VTE prophylaxis was not associated with lower incidence of VTE and mortality attributed to PE. Thus, routine screening may not be cost effective to prevent complications from DVT incidence.

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.

Does enoxaparin interfere with HMGB1 signaling after TBI? A potential mechanism for reduced cerebral edema and neurologic recovery

BACKGROUND

Enoxaparin (ENX) has been shown to reduce cerebral edema and improve neurologic recovery after traumatic brain injury (TBI), through blunting of cerebral leukocyte (LEU) recruitment. High mobility group box 1 (HMGB1) protein may induce inflammation through LEU activation. We hypothesized that ENX after TBI reduces LEU-mediated edema through blockade of HMGB1 signaling.

METHODS

Twenty-three CD1 mice underwent severe TBI by controlled cortical impact and were randomized to one of four groups receiving either monoclonal antibody against HMGB1 (MAb) or isotype (Iso) and either ENX (1 mg/kg) or normal saline (NS): NS + Iso (n = 5), NS + MAb (n = 6), ENX + Iso (n = 6), ENX + MAb (n = 6). ENX or NS was administered 2, 8, 14, 23 and 32 hours after TBI. MAb or Iso (25 μg) was administered 2 hours after TBI. At 48 hours, cerebral intravital microscopy served to visualize live LEU interacting with endothelium and microvascular fluorescein isothiocyanate-albumin leakage. The Neurological Severity Score (NSS) graded neurologic recovery; wet-to-dry ratios determined cerebral/lung edema. Analysis of variance with Bonferroni correction was used for statistical analyses.

RESULTS

ENX and MAb similarly reduced in vivo pial LEU rolling without demonstrating additive effect. In vivo albumin leakage was greatest in vehicle-treated animals but decreased by 25% with either MAb or ENX but by 50% when both were combined. Controlled cortical impact-induced cerebral wet-to-dry ratios were reduced by MAb or ENX without additive effect. Postinjury lung water was reduced by ENX but not by MAb. Neurologic recovery at 24 hours and 48 hours was similarly improved with ENX, MAb, or both treatments combined.

CONCLUSION

Mirroring ENX, HMGB1 signaling blockade reduces LEU recruitment, cerebrovascular permeability, and cerebral edema following TBI. ENX further reduced lung edema indicating a multifaceted effect beyond HMGB1 blockade. Further study is needed to determine how ENX may play a role in blunting HMGB1 signaling in brain injury patients.

Predictors of Outcomes in Traumatic Brain Injury

INTRODUCTION

The purpose of this study was to retrospectively evaluate patients treated for traumatic brain injuries (TBI) to determine how multiple organ trauma (MOT) and lung injuries sustained at the time of initial injury affect outcome.

METHODS

A single institution retrospective review of all patients diagnosed with TBI at a level I trauma center from 2000 to 2014 was conducted. Clinical outcome was based on Glasgow Outcome Scale at hospital discharge. Lung injury was defined as the presence of pulmonary contusions, pneumothorax, hemothorax, rib fractures, or diaphragmatic rupture proven by x-ray or computed tomography scan. MOT was defined as trauma to one body region with an Abbreviated Injury Scale (AIS) score ≥3 plus trauma to 2 additional body regions with AIS scores ≥1. Regression analysis was conducted with SPSS 21.

RESULTS

There were 409 patients reviewed. The majority of patients were male (73%), average age was 46 years (range, 16-94 years), average Glasgow Coma Scale (GCS) score was 7, and 71% had a severe TBI (GCS ≤8). Thirty percent of patients had poor outcome (Glasgow Outcome Scale = 1-2) Regression analysis indicated age (odds ratio [OR] 1.03, P < 0.001), initial GCS (OR 0.88, P < 0.001), Injury Severity Score (OR 1.03, P = 0.021), and head AIS ≥5 (OR 0.55, P = 0.019) were significant independent predictors of poor outcome. Sex, MOT, lung injury, and lung injury severity were not significant predictors of outcome.

CONCLUSIONS

Age, GCS, Injury Severity Score, and critical head injuries (AIS ≥5) were significant tools in predicting outcome in this patient cohort. MOT and traumatic lung injury may cause significant damage to a patient suffering from a severe TBI, but these injuries do not predict mortality in this patient population.

Splenectomy is associated with hypercoagulable thrombelastography values and increased risk of thromboembolism

BACKGROUND

Previous investigators have demonstrated that postinjury thrombocytosis is associated with an increase in thromboembolic (TE) risk. Increased rates of thrombocytosis have been found specifically in patients after splenectomy for trauma. We hypothesized that patients undergoing splenectomy (1) would demonstrate a more hypercoagulable profile during their hospital stay and (2) that this hypercoagulable state would be associated with increased TE events.

METHODS

This was a 14-month, prospective, observational trial evaluating serial rapid thrombelastography (rTEG) at 3 American College of Surgeons-verified, level 1 trauma centers. Inclusion criteria were highest-level trauma activation and arrival within 6 hours of injury. Exclusion criteria were <18 years of age, incarcerated, and burns>20% total body surface area. Serial rTEG (activated clotting time, k-time, α-angle, MA, lysis) and traditional coagulation testing (prothrombin time, partial thromboplastin time, fibrinogen and platelet count) were obtained at admission and then at 3, 6, 12, 24, 48, 72, 96, and 120 hours. Thromboembolic complications were defined as the development of deep-vein thrombosis, pulmonary embolism, acute myocardial infarction, or ischemic stroke during hospitalization. Patients were stratified into splenectomy versus nonsplenectomy cohorts. Univariate analysis was then conducted followed by longitudinal analysis using generalized estimating equations to evaluate the effects of time, splenectomy, and group-time interactions on changes in rTEG and traditional coagulation testing. We used an adjusted generalized estimating equation model to control for age, sex, ISS, admission blood pressure, base deficit, and hemoglobin.

RESULTS

A total of 1,242 patients were enrolled; 795 had serial rTEG data. Of these, 605 had serial values >24 hours and made up the study population. Splenectomy patients were younger, more hypotensive, and in shock on arrival. Although there was no difference in 24-hour or 30-day mortality, splenectomy patients were more likely to develop TE events. Using the GEE model, we found that α-angle and MA in splenectomy patients were lesser (more hypocoagulable) within the first 6 hours; however, they became substantially greater (more hypercoagulable) at 48, 72, 96, and 120 hours; all P < .05. In addition, platelet counts were greater in the splenectomy group beginning at 72 hours and continuing through 120 hours; P < .05.

CONCLUSION

This multicenter, prospective study demonstrates that patients undergoing splenectomy have a more hypercoagulable state than other trauma patients. This hypercoagulable state (identified by greater α-angle and mA values) begins at approximately 48 hours after injury and continues through at least day 5. Moreover, this hypercoagulable state is associated with increased risk of TE complications.