Optimal timing of venous thromboembolic chemoprophylaxis initiation following blunt solid organ injury: meta-analysis and systematic review

Venous thromboembolism chemoprophylaxis after severe polytrauma: timing and type of prophylaxis matter

In this review, we provide recommendations as well as summarize available data on the optimal time to initiate venous thromboembolism chemoprophylaxis after severe trauma. A general approach to the severe polytrauma patient is provided as well as in-depth reviews of three high-risk injury subgroups: patients with traumatic brain injury, solid organ injury, and pelvic fractures.

Optimal Timing for Initiation of Thromboprophylaxis After Hepatic Angioembolization

OBJECTIVE

To evaluate the optimal timing of thromboprophylaxis (TPX) initiation after hepatic angioembolization in trauma patients.

BACKGROUND

TPX after hepatic trauma is complicated by the risk of bleeding, but the relative risk after hepatic angioembolization is unknown.

METHODS

Patients who underwent hepatic angioembolization within 24 hours were retrospectively identified from the 2017 to 2019 American College of Surgeons Trauma Quality Improvement Project data sets. Cases with <24-hour length of stay and other serious injuries were excluded. Venous thromboembolism (VTE) included deep venous thrombosis and PE. Bleeding complications included hepatic surgery, additional angioembolization, or blood transfusion after TPX initiation. Differences were tested with univariate and multivariate analyses.

RESULTS

Of 1550 patients, 1370 had initial angioembolization. Bleeding complications were higher in those with TPX initiation within 24 hours (20.0% vs 8.9%, P <0.001) and 48 hours (13.2% vs 8.4%, P =0.013). However, VTE was higher in those with TPX initiation after 48 hours (6.3% vs 3.3%, P =0.025). In the 180 patients with hepatic surgery before angioembolization, bleeding complications were higher in those with TPX initiation within 24 hours (72% vs 20%, P <0.001), 48 hours (50% vs 17%, P <0.001), and 72 hours (37% vs 14%, P =0.001). Moreover, deep venous thrombosis was higher in those with TPX initiation after 96 hours (14.3% vs 3.1%, P =0.023).

CONCLUSIONS

This is the first study to address the timing of TPX after hepatic angioembolization in a national sample of trauma patients. For these patients, initiation of TPX at 48 to 72 hours achieves the safest balance in minimizing bleeding while reducing the risk of VTE.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

'Door-to-prophylaxis' as a novel quality improvement metric in prevention of venous thromboembolism following traumatic injury

Objective

Venous thromboembolism (VTE) risk reduction strategies include early initiation of chemoprophylaxis, reducing missed doses, weight-based dosing and dose adjustment using anti-Xa levels. We hypothesized that time to initiation of chemoprophylaxis would be the strongest modifiable risk for VTE, even after adjusting for competing risk factors.

Methods

A prospectively maintained trauma registry was queried for patients admitted July 2017-October 2021 who were 18 years and older and received emergency release blood products. Patients with deep vein thrombosis or pulmonary embolism (VTE) were compared to those without (no VTE). Door-to-prophylaxis was defined as time from hospital arrival to first dose of VTE chemoprophylaxis (hours). Univariate and multivariate analyses were then performed between the two groups.

Results

2047 patients met inclusion (106 VTE, 1941 no VTE). There were no differences in baseline or demographic data. VTE patients had higher injury severity score (29 vs 24), more evidence of shock by arrival lactate (4.6 vs 3.9) and received more post-ED transfusions (8 vs 2 units); all p<0.05. While there was no difference in need for enoxaparin dose adjustment or missed doses, door-to-prophylaxis time was longer in the VTE group (35 vs 25 hours; p=0.009). On multivariate logistic regression analysis, every hour delay from time of arrival increased likelihood of VTE by 1.5% (OR 1.015, 95% CI 1.004 to 1.023, p=0.004).

Conclusion

The current retrospective study of severely injured patients with trauma who required emergency release blood products found that increased door-to-prophylaxis time was significantly associated with an increased likelihood for VTE. Chemoprophylaxis initiation is one of the few modifiable risk factors available to combat VTE, therefore early initiation is paramount. Similar to door-to-balloon time in treating myocardial infarction and door-to-tPA time in stroke, "door-to-prophylaxis time" should be considered as a hospital metric for prevention of VTE in trauma.

Level of evidence

Level III, retrospective study with up to two negative criteria.

Weight-based enoxaparin thromboprophylaxis in young trauma patients: analysis of the CLOTT-1 registry

Introduction

Optimal venous thromboembolism (VTE) enoxaparin prophylaxis dosing remains elusive. Weight-based (WB) dosing safely increases anti-factor Xa levels without the need for routine monitoring but it is unclear if it leads to lower VTE risk. We hypothesized that WB dosing would decrease VTE risk compared with standard fixed dosing (SFD).

Methods

Patients from the prospective, observational CLOTT-1 registry receiving prophylactic enoxaparin (n=5539) were categorized as WB (0.45-0.55 mg/kg two times per day) or SFD (30 mg two times per day, 40 mg once a day). Multivariate logistic regression was used to generate a predicted probability of VTE for WB and SFD patients.

Results

Of 4360 patients analyzed, 1065 (24.4%) were WB and 3295 (75.6%) were SFD. WB patients were younger, female, more severely injured, and underwent major operation or major venous repair at a higher rate than individuals in the SFD group. Obesity was more common among the SFD group. Unadjusted VTE rates were comparable (WB 3.1% vs. SFD 3.9%; p=0.221). Early prophylaxis was associated with lower VTE rate (1.4% vs. 5.0%; p=0.001) and deep vein thrombosis (0.9% vs. 4.4%; p<0.001), but not pulmonary embolism (0.7% vs. 1.4%; p=0.259). After adjustment, VTE incidence did not differ by dosing strategy (adjusted OR (aOR) 0.75, 95% CI 0.38 to 1.48); however, early administration was associated with a significant reduction in VTE (aOR 0.47, 95% CI 0.30 to 0.74).

Conclusion

In young trauma patients, WB prophylaxis is not associated with reduced VTE rate when compared with SFD. The timing of the initiation of chemoprophylaxis may be more important than the dosing strategy. Further studies need to evaluate these findings across a wider age and comorbidity spectrum.

Level of evidence

Level IV, therapeutic/care management.

When is it safe to start venous thromboembolism prophylaxis after blunt solid organ injury? A prospective American Association for the Surgery of Trauma multi-institutional trial

BACKGROUND

The optimal time to initiate venous thromboembolism (VTE) chemoprophylaxis (VTEp) after blunt solid organ injury remains controversial, as VTE mitigation must be balanced against bleeding promulgation. Evidence from primarily small, retrospective, single-center work suggests that VTEp ≤48 hours is safe and effective. This study was undertaken to validate this clinical practice.

METHODS

Blunt trauma patients presenting to 19 participating trauma centers in North America were screened over a 1-year study period beginning between August 1 and October 1, 2021. Inclusions were age older than 15 years; ≥1 liver, spleen, or kidney injury; and initial nonoperative management. Exclusions were transfers, emergency department death, pregnancy, and concomitant bleeding disorder/anticoagulation/antiplatelet medication. A priori power calculation stipulated the need for 1,158 patients. Time of VTEp initiation defined study groups: Early (≤48 hours of admission) versus Late (>48 hours). Bivariate and multivariable analyses compared outcomes.

RESULTS

In total, 1,173 patients satisfied the study criteria with 571 liver (49%), 557 spleen (47%), and 277 kidney injuries (24%). The median patient age was 34 years (interquartile range, 25-49 years), and 67% (n = 780) were male. The median Injury Severity Score was 22 (interquartile range, 14-29) with Abbreviated Injury Scale Abdomen score of 3 (interquartile range, 2-3), and the median American Association for the Surgery of Trauma grade of solid organ injury was 2 (interquartile range, 2-3). Early VTEp patients (n = 838 [74%]) had significantly lower rates of VTE (n = 28 [3%] vs. n = 21 [7%], p = 0.008), comparable rates of nonoperative management failure (n = 21 [3%] vs. n = 12 [4%], p = 0.228), and lower rates of post-VTEp blood transfusion (n = 145 [17%] vs. n = 71 [23%], p = 0.024) when compared with Late VTEp patients (n = 301 [26%]). Late VTEp was independently associated with VTE (odd ratio, 2.251; p = 0.046).

CONCLUSION

Early initiation of VTEp was associated with significantly reduced rates of VTE with no increase in bleeding complications. Venous thromboembolism chemoprophylaxis initiation ≤48 hours is therefore safe and effective and should be the standard of care for patients with blunt solid organ injury.

LEVEL OF EVIDENCE

Therapeutic and Care Management; Level III.

Novel therapeutic medications for venous thromboembolism prevention in trauma patients: Findings from the Consensus Conference to Implement Optimal Venous Thromboembolism Prophylaxis in Trauma

ABSTRACT

Trauma patients are at high risk for venous thromboembolism (VTE). Despite evidence-based guidelines and concerted efforts in trauma centers to implement optimal chemoprophylaxis strategies, VTE remains a frequent diagnosis in trauma patients. Current chemoprophylaxis strategies largely focus on the subcutaneous injection of low-molecular-weight heparin, which is administered twice daily. Novel approaches to pharmacologic VTE prophylaxis have the potential to reduce VTE rates by improving patient compliance through oral administration or through their ability to target alternative pathways that mediate thrombosis. While novel pharmacologic VTE prophylaxis strategies have been studied in nontrauma patients, there is a paucity of literature in trauma patients where the risk of thrombosis versus hemorrhage must be carefully considered. As a component of the 2022 Consensus Conference to Implement Optimal VTE Prophylaxis in Trauma, this review provides an update of the novel chemoprophylaxis agents for potential use in trauma patients. Here, we will consider the relative risks and benefits related to the use of these drugs, evaluate the current literature in nontrauma patients, and consider future directions that could potentially improve posttrauma VTE prophylaxis.

Proceedings from the 2022 Consensus Conference to Implement Optimal Venous Thromboembolism Prophylaxis in Trauma

ABSTRACT

On May 4 and 5, 2022, a meeting of multidisciplinary stakeholders in the prevention and treatment of venous thromboembolism (VTE) after trauma was convened by the Coalition for National Trauma Research, funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health, and hosted by the American College of Surgeons in Chicago, Illinois. This consensus conference gathered more than 40 in-person and 80 virtual attendees, including trauma surgeons, other physicians, thrombosis experts, nurses, pharmacists, researchers, and patient advocates. The objectives of the meeting were twofold: (1) to review and summarize the present state of the scientific evidence regarding VTE prevention strategies in injured patients and (2) to develop consensus on future priorities in VTE prevention implementation and research gaps.To achieve these objectives, the first part of the conference consisted of talks from physician leaders, researchers, clinical champions, and patient advocates to summarize the current state of knowledge of VTE pathogenesis and prevention in patients with major injury. Video recordings of all talks and accompanying slides are freely available on the conference website ( https://www.nattrauma.org/research/research-policies-templates-guidelines/vte-conference/ ). Following this curriculum, the second part of the conference consisted of a series of small-group breakout sessions on topics potentially requiring future study. Through this process, research priorities were identified, and plans of action to develop and undertake future studies were defined.The 2022 Consensus Conference to Implement Optimal VTE Prophylaxis in Trauma answered the National Trauma Research Action Plan call to define a course for future research into preventing thromboembolism after trauma. A multidisciplinary group of clinical champions, physicians, scientists, and patients delineated clear objectives for future investigation to address important, persistent key knowledge gaps. The series of papers from the conference outlines the consensus based on the current literature and a roadmap for research to answer these unanswered questions.

Timing of venous thromboembolism prophylaxis initiation after injury: Findings from the consensus conference to implement optimal VTE prophylaxis in trauma

ABSTRACT

Optimizing prophylaxis against venous thromboembolic events (VTEs) is a critical issue in the care of injured patients. Although these patients are at significant risk of developing VTE, they also present competing concerns related to exacerbation of bleeding from existing injuries. Especially after high-risk trauma, including injuries to the abdominal solid organs, brain, and spine, trauma providers must delineate the time period in which VTE prophylaxis successfully reduces VTE rates without encouraging bleeding. Although existing data are primarily retrospective in nature and further study is required, literature supports early VTE chemoprophylaxis initiation even for severely injured patients. Early initiation is most frequently defined as <48 hours from admission but varies from <24 hours to 72 hours and occasionally refers to time from initial trauma. Prior to chemical VTE prophylaxis initiation in patients at risk for bleeding, an observation period is necessary during which injuries must show themselves to be hemostatic, either clinically or radiographically. In the future, prospective examination of optimal timing of VTE prophylaxis is necessary. Further study of specific subsets of trauma patients will allow for development of effective VTE mitigation strategies based upon collective risks of VTE and hemorrhage progression.

Thromboprophylaxis Timing After Blunt Solid Organ Injury: A Systematic Review and Meta-analysis

INTRODUCTION

Trauma patients with blunt abdominal solid organ injuries are at high risk for venous thromboembolism (VTE), but the optimal time to safely administer chemical thromboprophylaxis is controversial, especially for patients who are managed nonoperatively due to increased risk of hemorrhage. We sought to compare failure of nonoperative management (NOM) and VTE events based on timing of chemical thromboprophylaxis initiation.

METHODS

A systematic review was conducted in PubMed and Embase databases. Studies were included if they evaluated timing of initiation of chemical thromboprophylaxis in trauma patients who underwent NOM of blunt solid organ injuries. Outcomes included failure of NOM and incidence of VTE. A random-effects meta-analysis was performed comparing patients who received late (>48 h) versus early thromboprophylaxis initiation.

RESULTS

Twelve retrospective cohort studies, comprising 21,909 patients, were included. Three studies, including 6375 patients, provided data on adjusted outcomes. Pooled adjusted analysis demonstrated no difference in failure of NOM in patients receiving late versus early thromboprophylaxis (odds ratio [OR] 0.92, 95% confidence interval [CI]:0.4-2.14). When including all unadjusted studies, even those at high risk of bias, there remained no difference in failure of NOM (OR 1.16, 95% CI:0.72-1.86). In the adjusted analysis for VTE events, which had 6259 patients between two studies, patients receiving late chemical thromboprophylaxis had a higher risk of VTE compared with those who received early thromboprophylaxis (OR 1.89, 95% CI:1.15-3.12).

CONCLUSIONS

Based on current observational evidence, initiation of prophylaxis before 48 h is associated with lower VTE rates without higher risk of failure of NOM.

Venous thromboembolism risk after spinal cord injury: A secondary analysis of the CLOTT study

INTRODUCTION

Patients with spinal cord injury (SCI) are at high risk of venous thromboembolism (VTE). Pharmacologic VTE prophylaxis (VTEppx) is frequently delayed in patients with SCI because of concerns for bleeding risk. Here, we hypothesized that delaying VTEppx until >48 hours would be associated with increased risk of thrombotic events.

METHODS

This is a secondary analysis of the 2018 to 2020 prospective, observational, cohort Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study of patients aged 18 to 40 years, at 17 US level 1 trauma centers. Patients admitted for >48 hours with documented SCI were evaluated. Timing of initiation of VTEppx, rates of thrombotic events (deep vein thrombosis [DVT] and pulmonary embolism [PE]), and missed VTEppx doses were analyzed. The primary outcome was VTE (DVT + PE).

RESULTS

There were 343 patients with SCI. The mean ± SD age was 29.0 ± 6.6 years, 77.3% were male, and 78.7% sustained blunt mechanism. Thrombotic events occurred in 33 patients (9.6%): 30 DVTs (8.7%) and 3 PEs (0.9%). Venous thromboembolism prophylaxis started at ≤24 hours in 21.3% of patients and 49.3% at ≤48 hours. The rate of VTE for patients started on VTEppx ≤48 hours was 7.1% versus 12.1% if started after 48 hours ( p = 0.119). After adjusting for differences in risk factors between cohorts, starting ≤48 hours was independently associated with fewer VTEs (odds ratio, 0.45; 95% confidence interval, 0.101-0.978; p = 0.044). Unfractionated heparin was associated with a VTE rate of 21.0% versus 7.5% in those receiving enoxaparin as prophylaxis ( p = 0.003). Missed doses of VTEppx were common (29.7%) and associated with increased thrombotic events, although this was not significant on multivariate analysis.

CONCLUSION

Rates of thrombotic events in patients with SCI are high. Prompt initiation of VTEppx with enoxaparin and efforts aimed at avoiding missed doses are critical to limit thrombotic events in these high-risk patients.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Follow-up strategies for patients with splenic trauma managed non-operatively: the 2022 World Society of Emergency Surgery consensus document

Background

In 2017, the World Society of Emergency Surgery published its guidelines for the management of adult and pediatric patients with splenic trauma. Several issues regarding the follow-up of patients with splenic injuries treated with NOM remained unsolved.

Methods

Using a modified Delphi method, we sought to explore ongoing areas of controversy in the NOM of splenic trauma and reach a consensus among a group of 48 international experts from five continents (Africa, Europe, Asia, Oceania, America) concerning optimal follow-up strategies in patients with splenic injuries treated with NOM.

Results

Consensus was reached on eleven clinical research questions and 28 recommendations with an agreement rate ≥ 80%. Mobilization after 24 h in low-grade splenic trauma patients (WSES Class I, AAST Grades I–II) was suggested, while in patients with high-grade splenic injuries (WSES Classes II–III, AAST Grades III–V), if no other contraindications to early mobilization exist, safe mobilization of the patient when three successive hemoglobins 8 h apart after the first are within 10% of each other was considered safe according to the panel. The panel suggests adult patients to be admitted to hospital for 1 day (for low-grade splenic injuries—WSES Class I, AAST Grades I–II) to 3 days (for high-grade splenic injuries—WSES Classes II–III, AAST Grades III–V), with those with high-grade injuries requiring admission to a monitored setting. In the absence of specific complications, the panel suggests DVT and VTE prophylaxis with LMWH to be started within 48–72 h from hospital admission. The panel suggests splenic artery embolization (SAE) as the first-line intervention in patients with hemodynamic stability and arterial blush on CT scan, irrespective of injury grade. Regarding patients with WSES Class II blunt splenic injuries (AAST Grade III) without contrast extravasation, a low threshold for SAE has been suggested in the presence of risk factors for NOM failure. The panel also suggested angiography and eventual SAE in all hemodynamically stable adult patients with WSES Class III injuries (AAST Grades IV–V), even in the absence of CT blush, especially when concomitant surgery that requires change of position is needed. Follow-up imaging with contrast-enhanced ultrasound/CT scan in 48–72 h post-admission of trauma in splenic injuries WSES Class II (AAST Grade III) or higher treated with NOM was considered the best strategy for timely detection of vascular complications.

Conclusion

This consensus document could help guide future prospective studies aiming at validating the suggested strategies through the implementation of prospective trauma databases and the subsequent production of internationally endorsed guidelines on the issue.

Timing of pharmacologic venous thromboembolism prophylaxis initiation for trauma patients with nonoperatively managed blunt abdominal solid organ injury: a systematic review and meta-analysis

Background

Blunt abdominal solid organ injury is common and is often managed nonoperatively. Clinicians must balance risk of both hemorrhage and thrombosis. The optimal timing of pharmacologic venous thromboembolism prophylaxis (VTEp) initiation in this population is unclear. The objective was to evaluate early (< 48 h) compared to late initiation of VTEp in adult trauma patients with blunt abdominal solid organ injury managed nonoperatively.

Methods

Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched from inception to March 2021. Studies comparing timeframes of VTEp initiation were considered. The primary outcome was failure of nonoperative management (NOM) after VTEp initiation. Secondary outcomes included risk of transfusion, other bleeding complications, risk of deep vein thrombosis (DVT) and pulmonary embolism, and mortality.

Results

Ten cohort studies met inclusion criteria, with a total of 4642 patients. Meta-analysis revealed a statistically significant increase in the risk of failure of NOM among patients receiving early VTEp (OR 1.76, 95% CI 1.01–3.05, p = 0.05). There was no significant difference in risk of transfusion. Odds of DVT were significantly lower in the early group (OR 0.36, 95% CI 0.22–0.59, p < 0.0001). There was no difference in mortality (OR 1.50, 95% CI 0.82–2.75, p = 0.19). All studies were at serious risk of bias due to confounding.

Conclusions

Initiation of VTEp earlier than 48 h following hospitalization is associated with an increased risk of failure of NOM but a decreased risk of DVT. Absolute failure rates of NOM are low. Initiation of VTEp at 48 h may balance the risks of bleeding and VTE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13017-022-00423-1.