Hypercoagulability after trauma: hemostatic changes and relationship to venous thromboembolism

Whole blood storage duration alters fibrinogen levels and thrombin formation

INTRODUCTION

Whole blood resuscitation for hemorrhagic shock in trauma represents an opportunity to correct coagulopathy in trauma while also supplying red blood cells. The production of microvesicles in stored whole blood and their effect on its hemostatic parameters have not been described in previous literature. We hypothesized that microvesicles in aged stored whole blood are procoagulant and increase thrombin production via phosphatidylserine.

METHODS

Whole blood was obtained from male C57BL/6 male mice and stored in anticoagulant solution for up to 10 days. At intervals, stored whole blood underwent examination with rotational thromboelastography, and platelet-poor plasma was prepared for analysis of thrombin generation. Microvesicles were prepared from 10-day-old whole blood aliquots and added to fresh whole blood or platelet-poor plasma to assess changes in coagulation and thrombin generation. Microvesicles were treated with recombinant mouse lactadherin prior to addition to plasma to inhibit phosphatidylserine's role in thrombin generation.

RESULTS

Aged murine whole blood had decreased fibrin clot formation compared with fresh samples with decreased plasma fibrinogen levels. Thrombin generation in plasma from aged blood increased over time of storage. The addition of microvesicles to fresh plasma resulted in increased thrombin generation compared with controls. When phosphatidylserine on microvesicles was blocked with lactadherin, there was no difference in the endogenous thrombin potential, but the generation of thrombin was blunted with lower peak thrombin levels.

CONCLUSION

Cold storage of murine whole blood results in decreased fibrinogen levels and fibrin clot formation. Aged whole blood demonstrates increased thrombin generation, and this is due in part to microvesicle production in stored whole blood. One mechanism by which microvesicles are procoagulant is by phosphatidylserine expression on their membranes.

Pancreatectomy Induces Cancer-Promoting Neutrophil Extracellular Traps

BACKGROUND

Neutrophil extracellular traps (NETs) occur when neutrophil chromatin is decondensed and extruded into the extracellular space in a web-like structure. Originally described as an anti-microbial function, this process has been implicated in the pathogenesis of pancreatic disease. In addition, NETs are upregulated during physiologic wound-healing and coagulation. This study evaluated how the inflammatory response to pancreatic surgery influences NET formation.

METHODS

For this study, 126 patients undergoing pancreatectomy gave consent before participation. Plasma was collected at several time points (preoperatively and through the postoperative outpatient visit). Plasma levels of NET markers, including cell-free DNA (cfDNA), citrullinated histone H3 (CitH3), interleukin (IL)-8, IL-6, and granulocyte colony-stimulating factor (G-CSF) were measured using enzyme-linked immunosorbent assay (ELISA). Patient clinical data were retrospectively collected from a prospectively maintained database.

RESULTS

After pancreatic resection, NET markers (cfDNA and CitH3) were elevated, peaking on postoperative days 3 and 4. This increase in NETs was due to an inherent change in neutrophil biology. Postoperatively, NET-inducing cytokines (IL-8, IL-6, and G-CSF) were increased, peaking early in the postoperative course. The patients undergoing the robotic approach had a reduction in NETs during the postoperative period compared with those who underwent the open approach. The patients who experienced a pancreatic leak had an increase in NET markers during the postoperative period.

CONCLUSIONS

Pancreatectomy induces cancer-promoting NET formation. The minimally invasive robotic approach may induce fewer NETs, although the current analysis was limited by selection bias. Pancreatic leak resulted in increased NETs. Further study into the potential for NET inhibition during the perioperative period is warranted.

Clinical guidance for unfractionated heparin dosing and monitoring in critically ill patients

INTRODUCTION

Unfractionated heparin is a widely used anticoagulant in critically ill patients. It has a well-established safety profile and remains an attractive option for clinicians due to its short half-life and reversibility. Heparin has a unique pharmacokinetic profile, which contributes to significant inter-patient and intra-patient variability in effect. The variability in anticoagulant effect combined with heparin's short half-life mean close monitoring is required for clinical efficacy and preventing adverse effects. To optimize heparin use in critically ill patients, effective monitoring assays and dose adjustment strategies are needed.

AREAS COVERED

This paper explores the use of heparin as an anticoagulant and optimal approaches to monitoring in critically ill patients.

EXPERT OPINION

Conventional monitoring assays for heparin dosing have significant limitations. Emerging data appear to favor using anti-Xa assay monitoring for heparin anticoagulation, which many centers have successfully adopted as the standard. The anti-Xa assay appears have important benefits relative to the aPTT for heparin monitoring in critically ill patients, and should be considered for broader use.

Multicenter study evaluating target attainment of anti-Factor Xa levels using various enoxaparin prophylactic dosing practices in adult trauma patients

STUDY OBJECTIVE

Enoxaparin is standard of care for venous thromboembolism (VTE) prophylaxis in adult trauma patients, but fixed-dose protocols are suboptimal. Dosing based on body mass index (BMI) or total body weight (TBW) improves target prophylactic anti-Xa level attainment and reduces VTE rates. A novel strategy using estimated blood volume (EBV) may be more effective based on results of a single-center study. This study compared BMI-, TBW-, EBV-based, and hybrid enoxaparin dosing strategies at achieving target prophylactic anti-Factor Xa (anti-Xa) levels in trauma patients.

DESIGN

Multicenter, retrospective review.

DATA SOURCE

Electronic health records from participating institutions.

PATIENTS

Adult trauma patients who received enoxaparin twice daily for VTE prophylaxis and had at least one appropriately timed anti-Xa level (collected 3 to 6 hours after the previous dose after three consecutive doses) from January 2017 through December 2020. Patients were excluded if the hospital-specific dosing protocol was not followed or if they had thermal burns with > 20% body surface area involvement.

INTERVENTION

Dosing strategy used to determine initial prophylactic dose of enoxaparin.

MEASUREMENTS

The primary end point was percentage of patients with peak anti-Xa levels within the target prophylactic range (0.2-0.4 units/mL).

MAIN RESULTS

Nine hospitals enrolled 742 unique patients. The most common dosing strategy was based on BMI (43.0%), followed by EBV (29.0%). Patients dosed using EBV had the highest percentage of target anti-Xa levels (72.1%). Multiple logistic regression demonstrated EBV-based dosing was significantly more likely to yield anti-Xa levels at or above target compared to BMI-based dosing (adjusted odds ratio (aOR) 3.59, 95% confidence interval (CI) 2.29-5.62, p < 0.001). EBV-based dosing was also more likely than hybrid dosing to yield an anti-Xa level at or above target (aOR 2.30, 95% CI 1.33-3.98, p = 0.003). Other pairwise comparisons between dosing strategy groups were nonsignificant.

CONCLUSIONS

An EBV-based dosing strategy was associated with higher odds of achieving anti-Xa level within target range for enoxaparin VTE prophylaxis compared to BMI-based dosing and may be a preferred method for VTE prophylaxis in adult trauma patients.

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.

Comparative study of two models predicting the risk of deep vein thrombosis progression in spinal trauma patients after operation

OBJECTIVE

Patients with preoperative deep vein thrombosis (DVT) exhibit a notable incidence of postoperative deep vein thrombosis progression (DVTp), which bears a potential for silent, severe consequences. Consequently, the development of a predictive model for the risk of postoperative DVTp among spinal trauma patients is important.

METHODS

Data of 161 spinal traumatic patients with preoperative DVT, who underwent spine surgery after admission, were collected from our hospital between January 2016 and December 2022. The least absolute shrinkage and selection operator (LASSO) combined with multivariable logistic regression analysis was applied to select variables for the development of the predictive logistic regression models. One logistic regression model was formulated simply with the Caprini risk score (Model A), while the other model incorporated not only the previously screened variables but also the age variable (Model B). The model's capability was evaluated using sensitivity, specificity, positive predictive value, negative predictive value, accuracy, F1 score, and receiver operating characteristic (ROC) curve. Nomograms simplified and visually presented Model B for the clinicians and patients to understand the predictive model. The decision curve was used to analyze the clinical value of Model B.

RESULTS

A total of 161 DVT patients were enrolled in this study. Postoperative DVTp occurred in 48 spinal trauma patients, accounting for 29.81% of the total patient enrolled. Model A inadequately predicted postoperative DVTp in spinal trauma patients, with ROC AUC values of 0.595 for the training dataset and 0.593 for the test dataset. Through the application of LASSO regression and multivariable logistic regression, a screening process was conducted for seven risk factors: D-dimer, blood platelet, hyperlipidemia, blood group, preoperative anticoagulant, spinal cord injury, lower extremity varicosities. Model B demonstrated superior and consistent predictive performance, with ROC AUC values of 0.809 for the training dataset and 0.773 for the test dataset. According to the calibration curves and decision curve analysis, Model B could accurately predict the probability of postoperative DVTp after spine surgery. The nomograms enhanced the interpretability of Model B in charts and graphs.

CONCLUSIONS

In summary, we established a logistic regression model for the accurate predicting of postoperative deep vein thrombosis progression in spinal trauma patients, utilizing D-dimer, blood platelet, hyperlipidemia, blood group, preoperative anticoagulant, spinal cord injury, lower extremity varicosities, and age as predictive factors. The proposed model outperformed a logistic regression model based simply on CRS. The proposed model has the potential to aid frontline clinicians and patients in identifying and intervening in postoperative DVTp among traumatic patients undergoing spinal surgery.

Coagulation Status Using Clot Wave Analysis in Patients With Prolonged Immobilization

Background Prolonged immobilization is widely recognized as a risk factor for thromboembolism. In this prospective study, we investigated the changes in clot waveform analysis (CWA) parameters in prolonged immobilized patients following lower limb trauma. CWA is an advanced method for assessing global coagulation that involves continuously monitoring changes in light transmittance, absorbance, or light scattering during routine clotting tests. Additionally, we also aim to determine the CWA parameters between day one and after day three of immobilization. Methods A total of 30 patients with prolonged immobilization were enrolled in this study. The plasma of these patients was collected on the first day of their admission and subsequently obtained again after day three of immobilization. Prothrombin time (PT)-based CWA and activated partial thromboplastin time (aPTT)-based CWA were performed using the ACL TOP 300 CTS (Werfen: Bedford, USA) coagulation analyzer, which utilizes the optical method for clot detection. Plasma samples for 20 normal controls were recruited from a healthy blood donor. The CWA parameters generated during clot formation were analyzed. For the comparison of CWA parameters between patients with prolonged immobilization and healthy controls, the Mann-Whitney test was used. A paired t-test was used for the comparison of clot wave parameters between day one and after day three of immobilization. This study was approved by the Universiti Sains Malaysia Research Ethics Committee. Result The mean values of PT and aPTT in healthy controls were 11.66 seconds and 33.98 seconds, respectively. There was no statistically significant difference between the patients and the healthy controls in the median values of aPTT (P=0.935). However, patients with prolonged immobilization exhibited significantly higher median PT CWA parameter values than controls (P=0.007). These parameters included the delta change (P<0.001), peak time velocity (P=0.008), and height velocity (P<0.001). On the other hand, the delta change (P<0.001) and height velocity (P<0.001) of the aPTT CWA parameters were significantly higher in patients with prolonged immobilization than in controls. In patients with prolonged immobilization, there was no significant difference in PT CWA parameters between day one and after day three of immobilization, while for aPTT CWA, all parameters were higher on day three, except for the endpoint time. Conclusion Patients with prolonged immobilization exhibit increased PT and aPTT CWA parameters compared to normal controls. CWA parameters could aid in identifying patients at risk of developing thrombosis through changes in the clot waveform. However, further study is needed to fully utilize additional information from routine coagulation testing.

Haemostatic, Inflammatory, and Haematological Biomarkers Among Orthopaedic Patients With Prolonged Immobilization and the Risk of Hypercoagulable States

Background Venous thromboembolism (VTE) is a common and potentially life-threatening complication in patients with lower limb traumatic fractures. Orthopaedic patients who experience trauma in the lower limbs with prolonged immobilization may experience a hypercoagulable state, which could eventually lead to the development of VTE. Therefore, this study aims to evaluate the changes in hypercoagulable markers, including haemostatic, inflammatory, and haematological biomarkers in orthopaedic trauma patients with prolonged immobilization. Materials/method This prospective cohort study was conducted at Hospital Universiti Sains Malaysia from August 2020 to March 2022. Every patient with fractures in the lower limbs was screened for eligibility, and patients who required immobilization for more than five days without receiving anticoagulant prophylaxis were recruited for this study. The laboratory tests, including D-dimer, fibrinogen, prothrombin time (PT), activated partial thromboplastin time (aPTT), erythrocyte sedimentation rate (ESR), and platelet count, were serially measured on day one and day five of hospitalization. The biomarkers were analyzed using a paired t-test, with a p-value <0.05 as a significant result. Results A total of 54 patients with fractures in the lower limbs, ages ranging from 12 to 50 years old, were involved in this study. The paired t-test analysis demonstrated that several biomarkers showed a significant increase in mean difference between day one and day five of immobilization, which included fibrinogen, ESR, and platelet count. The mean differences for each biomarker with fibrinogen were 0.66 g/L (p<0.001, 95% CI of mean difference: -1.04, -0.27), ESR increased by 17.98mm/hr (p<0.001, 95% CI of mean difference: -24.69, -11.27), and platelet count increased by 128.59×109/L (p<0.001, 95% CI of mean difference: -166.55, -90.64) on day five of immobilization. D-dimer was elevated in all patients on both post-trauma days; however, no significant difference was observed in this biomarker between day one and day five of immobilization. Conclusion In conclusion, our study found that fibrinogen, ESR, and platelet count levels were significantly increased in orthopaedic trauma patients with prolonged immobilization. The increase in these biomarkers indicates the body's reaction to tissue injury after trauma, which may contribute to the hypercoagulable states. Further research with a larger sample size is warranted to assess the viability of these biomarkers as potential diagnostic indicators for the development of VTE related to hypercoagulability.

Efficacy of the bleeding risk scoring system for optimal prophylactic anticoagulation therapy of venous thromboembolism in trauma patients: a single-center, retrospective, observational cohort study

BACKGROUND

We developed a bleeding risk scoring system (BRSS) using prophylactic anticoagulation therapy to comprehensively assess the risk of venous thromboembolism (VTE) in trauma patients. This study evaluated the usefulness of this system in trauma patients, with a focus on minimizing the rate of bleeding events associated with prophylactic anticoagulation therapy.

METHODS

We retrospectively evaluated the efficacy of BRSS in trauma patients who received prophylactic anticoagulation therapy for VTE at the Kitasato University Hospital Emergency and Critical Care Center between April 1, 2015, and August 31, 2020. To compare the incidence of bleeding events, patients were divided into two groups: one group using the BRSS (BRSS group) and another group not using the BRSS (non-BRSS group).

RESULTS

A total of 94 patients were enrolled in this study, with 70 and 24 patients assigned to the non-BRSS and BRSS groups, respectively. The major bleeding event rates were not significantly different between the two groups (BRSS group, 4.2%; non-BRSS group, 5.7%; p = 1.000). However, minor bleeding events were significantly reduced in the BRSS group (4.2% vs.27.1%; p = 0.020). Multivariate logistic regression analysis showed that BRSS was not an independent influencing factor of major bleeding events (odds ratio, 0.660; 95% confidence interval: 0.067-6.47; p = 0.721). Multivariate logistic regression analysis showed that BRSS was an independent influencing factor of minor bleeding events (odds ratio, 0.119; 95% confidence interval: 0.015-0.97; p = 0.047). The incidence of VTE did not differ significantly between groups (BRSS group, 4.2%; non-BRSS group, 8.6%; p = 0.674).

CONCLUSIONS

BRSS may be a useful tool for reducing the incidence of minor bleeding events during the initial prophylactic anticoagulation therapy in trauma patients. There are several limitations of this study that need to be addressed in future research.

Early administration of high dose enoxaparin after traumatic brain injury

BACKGROUND

Early enoxaparin 30 mg BID administration at 24 h post-injury has been demonstrated in patients with traumatic brain injury (TBI). However this dose can also yield subtherapeutic anti-Xa levels in 30-50% of trauma patients, suggesting that larger doses may be required for adequate prophylaxis against venous thromboembolism (VTE). The safety of enoxaparin 40 mg BID in trauma patients has previously been shown - however, these studies have largely excluded TBI patients. Therefore, we sought to demonstrate the safety of early enoxaparin 40 mg BID in a low-risk group of TBI patients.

METHODS

A retrospective review of TBI patients at a Level 1 trauma center was performed. Patients with stable computed tomography (CT) of the head at 6 to 24 h post-injury who received enoxaparin 40 mg BID were included and serial GCS evaluations to identify possible clinical complications. To evaluate the safety of this dosing regimen, data was then compared to patients from our institution with similar TBI profiles who had received 5,000 units (U) of subcutaneous heparin (SQH) prophylaxis.

RESULTS

199 TBI patients were identified over a nine month period, 40/199 (19.7%) received DVT prophylaxis after traumatic injury. Of these 40, 19 (47.5%) received enoxaparin 40 mg BID and 21 (52.5%) received 5,000U of SQH. Low risk TBI patients who were either given enoxaparin (n = 7) or SQH (n = 4), demonstrated no clinical decline in mental status during their inpatient stay.

CONCLUSION

Prior studies have demonstrated that enoxaparin 40 mg BID dosing is superior to traditional VTE prophylaxis in trauma patients. However, TBI patients are often excluded from this dosing due to concern for progression. Our study showed no clinical decline in mental status in a small cohort of low-risk TBI patients who received enoxaparin 40 mg BID.

Outcomes Following Below Knee Arterial Trauma

INTRODUCTION

Lower extremity vascular injuries have significant implications for trauma patients with regards to morbidity from limb loss. There is limited evidence on outcomes for patients with injuries to tibial arteries. Our study focuses on defining outcomes of traumatic vascular injury to vessels below the knee.

METHODS

A retrospective review using ICD-9 and 10 codes of all patients with below knee vascular injuries was performed at a Level 1 trauma center from November 2014 to June 2022. Interventions, outcomes, and complications were assessed.

RESULTS

Seventy-six patients were identified fitting inclusion criteria. The mean age was 35.3 +/- 15.2 years and 67 (88%) patients were male. Thirty-nine suffered penetrating trauma, 37 suffered blunt trauma. The most injured artery was posterior tibial artery (40%) followed by anterior tibial artery (36%). Injuries included 51 transections, 22 occlusions and 4 pseudoaneurysms. Forty-five (59%) patients underwent operative intervention. Thirty (67%) operations were performed by trauma surgery. Arterial ligation was performed in 30 cases (67%), arterial bypass in 12 (27%), and 2 (4%) primary amputations. Vascular surgery performed all bypasses. Overall amputation rate was 8% (n = 6) with 3 for mangled extremity and 3 due to failed bypass graft. All amputations were associated with open fracture and amputations for failed bypass had multiple arterial injuries.

CONCLUSION

The management of below knee vascular trauma requires a multidisciplinary approach. Patients requiring reconstruction are more likely to have multiple vessel injuries and may have significant risk of graft failure. These patients as well as those with extensive soft tissue injury and/or multi-vessel injuries are at increased risk for amputation.

Traumatic Brain Injury and Long-Term Risk of Stroke Among US Military Veterans

BACKGROUND

Traumatic brain injury (TBI) is associated with significant morbidity, but the association of TBI with long-term stroke risk in diverse populations remains less clear. Our objective was to examine the long-term associations of TBI with stroke and to investigate potential differences by age, sex, race and ethnicity, and time since TBI diagnosis.

METHODS

Retrospective cohort study of US military veterans aged 18+ years receiving healthcare in the Veterans Health Administration system between October 1, 2002 and September 30, 2019. Veterans with TBI were matched 1:1 to veterans without TBI on age, sex, race and ethnicity, and index date, yielding 306 796 veterans with TBI and 306 796 veterans without TBI included in the study. In primary analyses, Fine-Gray proportional hazards models adjusted for sociodemographics and medical/psychiatric comorbidities were used to estimate the association between TBI and stroke risk, accounting for the competing risk of mortality.

RESULTS

Participants were a mean age of 50 years, 9% were female, and 25% were of non-White race and ethnicity. Overall, 4.7% of veterans developed a stroke over a median follow-up of 5.2 years. Veterans with TBI had 1.69 times (95% CI, 1.64-1.73) increased risk of any stroke (ischemic or hemorrhagic) compared to veterans without TBI. This increased risk was highest in the first-year post-TBI diagnosis (hazard ratio [HR], 2.16 [95% CI, 2.03-2.29]) but remained elevated for 10+ years. Similar patterns were observed for secondary outcomes, with associations of TBI with hemorrhagic stroke (HR, 3.92 [95% CI, 3.59-4.29]) being stronger than with ischemic stroke (HR, 1.56 [95% CI, 1.52-1.61]). Veterans with both mild (HR, 1.47 [95% CI, 1.43-1.52]) and moderate/severe/penetrating injury (HR, 2.02 [95% CI, 1.96-2.09]) had increased risk of stroke compared to veterans without TBI. Associations of TBI with stroke were stronger among older compared to younger individuals (P interaction-by-age<0.001) and were weaker among Black veterans compared to other race and ethnicities (P interaction-by-race<0.001).

CONCLUSIONS

Veterans with prior TBI are at increased long-term risk for stroke, suggesting they may be an important population to target for primary stroke prevention measures.

Thrombophilia and Preoperative Deep Venous Thrombosis and Their Effect on Free Flap Survival: A Scoping Review

Background: A proper preoperative planning is essential to prevent flap failure. However, venous workup for flaps has not been commonly performed or utilized as a preoperative screening tool. A scoping review was conducted to explore preoperative venous system screening, including deep vein thrombosis diagnosis, and its effect on flap survival rate. This review identified existing gaps of knowledge and emphasized potential research areas for future studies. Methods: Two independent reviewers searched 3 electronic databases from inception to September 2020. Retrieved appropriate articles were selected systematically by title, abstract, and full review of the article. Studies were included if they enrolled patients who had thrombophilia or deep venous thrombosis (DVT) preoperatively and had undergone a free flap reconstruction. For eligible studies, the following information was extracted: basic demographics (sex, age, comorbidities), preoperative scans type, free flap type, clotting mode (causes), wound type, and flap survival. Results: Seventeen articles were found eligible for this review. Traumatic aetiology was found in 63 (33.6%) patients, while 124 (66.3%) patients had a non-traumatic aetiology. Preoperative screening for patients with non-traumatic aetiology was reported in 119 patients. In these patients, the flap survived in 107 (89.91%) patients. Four studies investigating patients with traumatic DVT aetiology, 60 patients (out of 63) had a preoperative computed tomography angiography or duplex. Those patients had 100% flap survival rates. Conclusion: Further investigations are required to identify venous thrombosis incidence in patients with non-traumatic thrombosis aetiology as this cohort of patients is at high risk of flap failure. Finally, the prognostic validity of available preoperative screening tools to identify high-risk patients should be assessed, such as imaging techniques, which would include venous duplex scanning, may prevent failure in free flap surgery.

Factor VIII: A Dynamic Modulator of Hemostasis and Thrombosis in Trauma

A trace amount of thrombin cleaves factor VIII (FVIII) into an active form (FVIIIa), which catalyzes FIXa-mediated activation of FX on the activated platelet surface. FVIII rapidly binds to von Willebrand factor (VWF) after secretion and becomes highly concentrated via VWF-platelet interaction at a site of endothelial inflammation or injury. Circulating levels of FVIII and VWF are influenced by age, blood type (nontype O > type O), and metabolic syndromes. In the latter, hypercoagulability is associated with chronic inflammation (known as thrombo-inflammation). In acute stress including trauma, releasable pools of FVIII/VWF are secreted from the Weibel-Palade bodies in the endothelium and then augment local platelet accumulation, thrombin generation, and leukocyte recruitment. Early systemic increases of FVIII/VWF (>200% of normal) levels in trauma result in a lower sensitivity of contact-activated clotting time (activated partial thromboplastin time [aPTT] or viscoelastic coagulation test [VCT]). However, in severely injured patients, multiple serine proteases (FXa plasmin and activated protein C [APC]) are locally activated and may be systemically released. Severity of traumatic injury correlates with prolonged aPTT and elevated activation markers of FXa, plasmin, and APC, culminating in a poor prognosis. In a subset of acute trauma patients, cryoprecipitate that contains fibrinogen, FVIII/VWF, and FXIII is theoretically advantageous over purified fibrinogen concentrate to promote stable clot formation, but comparative efficacy data are lacking. In chronic inflammation or subacute phase of trauma, elevated FVIII/VWF contributes to the pathogenesis of venous thrombosis by enhancing not only thrombin generation but also augmenting inflammatory functions. Future developments in coagulation monitoring specific to trauma patients, and targeted to enhancement or inhibition of FVIII/VWF, are likely to help clinicians gain better control of hemostasis and thromboprophylaxis. The main goal of this narrative is to review the physiological functions and regulations of FVIII and implications of FVIII in coagulation monitoring and thromboembolic complications in major trauma patients.

Enhanced in vivo and ex vivo thrombin generation after lower-leg trauma, but not after knee arthroscopy

BACKGROUND

There is room for improvement of prevention of venous thromboembolism (VTE) after lower-leg cast application or knee arthroscopy. Information about the mechanism of clot formation in these patients may be useful to identify new prophylaxis targets. We aimed to study the effect of 1) lower-leg injury and 2) knee arthroscopy on thrombin generation.

METHODS

A cross-sectional study was conducted using plasma samples of POT-(K)CAST trials to measure ex vivo thrombin generation (Calibrated Automated Thrombography [CAT]) and plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT), fibrinopeptide A (FPA). Plasma was obtained shortly after lower-leg trauma or before and after (< 4 h) knee arthroscopy. Participants were randomly selected from those who did not develop VTE. For aim 1, samples of 88 patients with lower-leg injury were compared with 89 control samples (i.e., preoperative samples of arthroscopy patients). Linear regression was used to obtain mean differences (or ratios if ln-retransformed because of skewedness) adjusted for age, sex, body mass index, comorbidities. For aim 2, pre- and postoperative samples of 85 arthroscopy patients were compared, for which mean changes were obtained.

RESULTS

In patients with lower-leg injury (aim 1), endogenous thrombin potential, thrombin peak, velocity index, FPA and TAT were increased as compared with controls. In arthroscopy patients (aim 2), pre- and postoperative levels were similar for all parameters.

CONCLUSION

Lower-leg trauma increases thrombin generation both ex vivo and in vivo, in contrast to knee arthroscopy. This may imply that the pathogenesis of VTE is different in both situations.

Haemostasis and Inflammatory Parameters as Potential Diagnostic Biomarkers for VTE in Trauma-Immobilized Patients

Venous thromboembolism (VTE), which encompasses deep venous thrombosis (DVT) and pulmonary embolism (PE), is a major public health concern due to its high incidences of morbidity and mortality. Patients who have experienced trauma with prolonged immobilization are at an increased risk of developing VTE. Plasma D-dimer levels have been known to be elevated in trauma patients, and they were closely correlated with the number of fractures. In other words, plasma D-dimer levels cannot be used as the only indicator of VTE in trauma cases. Given the limitations, further study is needed to explore other potential biomarkers for diagnosing VTE. To date, various established and novel VTE biomarkers have been studied in terms of their potential for predicting VTE, diagnostic performance, and improving clinical therapy for VTE. Therefore, this review aims to provide information regarding classic and essential haemostasis (including prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, fibrinogen, thrombin generation, protein C, protein S, antithrombin, tissue factor pathway inhibitor, and platelet count) and inflammatory biomarkers (C-reactive protein, erythrocyte sedimentation rate, and soluble P-selectin) as potential diagnostic biomarkers that can predict the risk of VTE development among trauma patients with prolonged immobilization. Thus, further advancement in risk stratification using these biomarkers would allow for a better diagnosis of patients with VTE, especially in areas with limited resources.

Empiric tranexamic acid use provides no benefit in urgent orthopedic surgery following injury

Background

Orthopedic literature has demonstrated a significant decrease in postoperative transfusion requirements when tranexamic acid (TXA) was given during elective joint arthroplasty. The purpose of this study was to evaluate the empiric use of TXA in semi-urgent orthopedic procedures following injury. We hypothesized that TXA would be associated with increased rates of venous thromboembolic events (VTE) and have no effect on transfusion requirements.

Methods

Patients who empirically received TXA during a semi-urgent orthopedic surgery following injury (TXA+) were matched using propensity scoring to historical controls (CONTROL) who did not receive TXA. Outcomes included VTE within 6 months of injury and packed red blood cell utilization. Multivariable logistic regression and generalized linear modeling were used to determine odds of VTE and transfusion.

Results

200 patients were included in each group. There was no difference in mortality between groups. TXA+ patients did not have an increase in VTE events (OR 0.680, 95% CI 0.206 to 2.248). TXA+ patients had a significantly higher odds of being transfused during their hospital stay (OR 2.175, 95% CI 1.246 to 3.797) and during the index surgery (increased 0.95 units (SD 0.16), p<0.0001). Overall transfusion was also significantly higher in the TXA+ group (p=0.0021).

Conclusion

Empiric use of TXA in semi-urgent orthopedic surgeries did not increase the odds of VTE. Despite the elective literature, TXA administration did not associate with less transfusion requirements. A properly powered, prospective, randomized trial should be designed to elucidate the risks and benefits associated with TXA use in this setting.

Level of evidence

Level IV.

THE EFFICACY OF WEIGHT-BASED ENOXAPARIN DOSING FOR VTE-PROPHYLAXIS IN TRAUMA PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

Trauma patients are at high risk of developing venous thromboembolism (VTE), and standard dosing enoxaparin regimens may be inadequate for prophylaxis. This meta-analysis was performed to clarify the efficacy of alternative dosing regimens for VTE prophylaxis in this high-risk group. The objective of this systematic review was to review the evidence regarding weight-based dosing of enoxaparin for VTE prophylaxis in trauma patients.

METHODS

A systematic database search was undertaken for studies comparing standard vs weight-based dosing of enoxaparin for VTE prophylaxis in adult trauma patients, aged ≥18 years. The primary outcome was the achievement of Anti-Factor Xa (AFXa) levels within the prophylactic range. Secondary outcomes included: sub-prophylactic AFXa levels, supra-prophylactic AFXa levels, VTE incidence and bleeding events. Meta-analysis was conducted using both fixed- and random-effects models, and presented as odds ratios (OR), risk ratios (RR) and risk differences (RD) with 95% confidence intervals (CI).

RESULTS

Four cohort studies were eligible for inclusion. Compared to standard dosing, weight-based enoxaparin prophylaxis dosing was associated with increased odds of prophylactic AFXa levels (OR = 5.85., 95%CI: 3.02-11.30, p < 0.00001) and reduced risk of sub-prophylactic AFXa levels (RR = 3.97, 95%CI: 3.02-5.22, p < 0.00001). Standard dosing was associated with a reduced risk of supra-therapeutic AFXa levels (RR = 0.23, 95%CI: 0.11-0.50, P = 0.0002), but this was not associated with a difference in risk of bleeding events (RD = -0.00, 95%CI: -0.02-0.01, P = 0.55). There was no statistical difference in incidence VTE between the two groups (RD = 0.01, 95%CI: -0.02-0.03, P = 0.64).

CONCLUSIONS

Compared with standard dosing, weight-based enoxaparin dosing regimens are associated with increased odds of prophylactic range AFXa levels. Further investigation is required to determine if this translates into improved VTE prophylaxis and reduced VTE incidence.

LEVEL OF EVIDENCE

Systematic Review, level III.

Prevalence of preoperative Deep Venous Thrombosis (DVT) following elderly intertrochanteric fractures and development of a risk prediction model

Background

This study aimed to investigate the prevalence of preoperative deep venous thrombosis (DVT) following intertrochanteric fractures in the elderly and identify the associated factors, based on which a risk prediction model was developed.

Method

This was a retrospective single-center study of elderly patients presenting with intertrochanteric fractures between our institution between January 2017 and December 2020. Patients' duplex ultrasound (DUS) or venography results were retrieved to evaluate whether they had a preoperative deep venous thrombosis (DVT) of bilateral extremities, whereby patients were dichotomized. Various variables of interest on demographics, comorbidities, injury and biomarkers were extracted and their relationship between DVT were investigated. Statistically significant variables tested in multivariate logistics regression analyses were used to develop a risk prediction model.

Results

There were 855 patients eligible to be included in this study, and 105 were found to have preoperative DVT, with a prevalence rate of 12.3%. Ten factors were tested as significantly different and 2 marginally significant between DVT and non-DVT groups in the univariate analyses, but only 6 demonstrated the independent effect on DVT occurrence, including history of a VTE event (OR, 4.43; 95%CI, 2.04 to 9.62), time from injury to DVT screening (OR, 1.19; 95%CI, 1.13 to 1.25), BMI (OR, 1.11; 95%CI, 1.04–1.18), peripheral vascular disease (OR, 2.66; 95%CI, 1.10 to 6.40), reduced albumin (2.35; 95%CI, 1.48 to 3.71) and D-Dimer > 1.0 mg/L(OR, 1.90; 95%CI, 1.13 to 3.20). The DVT risk model showed an AUC of 0.780 (95%CI, 0.731 to 0.829), with a sensitivity of 0.667 and a specificity of 0.777.

Conclusion

Despite without a so high prevalence rate of DVT in a general population with intertrochanteric fracture, particular attention should be paid to those involved in the associated risk factors above. The risk prediction model exhibited the improved specificity, but its validity required further studies to verify.

Preoperative incidence and risk factors of deep venous thrombosis in patients with isolated femoral shaft fracture

Background

Preoperative deep vein thrombosis (DVT) of the lower extremities delays surgery in patients with femoral shaft fractures and impairs functional recovery. However, studies on preoperative DVT in patients with femoral shaft fractures are still rare. This study was aimed to retrospectively analyze the preoperative incidence, location and risk factors associated with DVT in patients with femoral shaft fractures.

Methods

Data of patients with femoral shaft fractures and treated with surgery at the Third Hospital of Hebei Medical University were retrospectively collected from January 2013 to December 2019. The information collected included demographic data, comorbidities, injury-related data and laboratory tests. Patients were divided into DVT and non-DVT groups. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors.

Results

A total of 432 patients were included in this study, of whom 114 (26.4%) patients were diagnosed with preoperative DVT (all asymptomatic) and injured extremities of 78.1% (89/114) were investigated. Multivariate analysis showed that older age (increase in each 10 years), delay time from injury to operation (in each day), FIB > 4 g/L were independent risk factors for preoperative DVT.

Conclusion

Patients with femoral shaft fractures (especially the elderly and patients with the above-mentioned conditions) are at the risk of DVT right from admission to surgery hence should be intensively monitored and provided with prompt treatment to prevent DVT.

Variations in clot phenotype following injury: The MA-R ratio and fragile clots

INTRODUCTION

Trauma-induced coagulopathy is a continuum ranging from hypercoagulable to hypercoagulable phenotypes. In single-center studies, the maximum amplitude (MA) to r-time (R) (MA-R) ratio has identified a phenotype of injured patients with high mortality risk. The purpose of this study was to determine the relationship between MA-R and mortality using multicenter data and to investigate fibrinogen consumption in the development of this specific coagulopathy phenotype.

METHODS

Using the Pragmatic Randomized Optimal Platelet and Plasma Ratios data set, patients were divided into blunt and penetrating injury cohorts. MA was divided by R time from admission thromboelastogram to calculate MA-R. MA-R was used to assess odds of early and late mortality using multivariable models. Multivariable models were used to assess thrombogram values in both cohorts. Refinement of the MA-R cut point was performed with Youden index. Repeat multivariable analysis was performed with a binary CRITICAL and NORMAL MA-R.

RESULTS

In initial analysis, MA-R quartiles were not associated with mortality in the penetrating cohort. In the blunt cohort, there was an association between low MA-R and early and late mortality. A refined cut point of 11 was identified (CRITICAL: MA-R, ≤11; NORMAL: MA-R, >11). CRITICAL MA-R was associated with mortality in both penetrating and blunt subgroups. In further injury subgroup analysis, CRITICAL patients had significantly decreased fibrinogen levels in the blunt subgroup only. In both blunt and penetrating injury, there was no difference in time to initiation of thrombin burst (lagtime). However, both endogenous thrombin potential and peak thrombin levels were significantly lower in CRITICAL patients.

CONCLUSIONS

MA-R identifies a trauma-induced coagulopathy phenotype characterized in blunt injury by impaired thrombin generation that is associated with early and late mortality. The endotheliopathy and tissue factor release likely plays a role in the cascade of impaired thrombin burst, possible early fibrinogen consumption and the weaker clot identified by MA-R.

LEVEL OF EVIDENCE

Therapeutic/care management, level II.

American Association for the Surgery of Trauma/American College of Surgeons-Committee on Trauma Clinical Protocol for inpatient venous thromboembolism prophylaxis after trauma

ABSTRACT

Trauma patients are at increased risk of venous thromboembolism (VTE), which includes both deep vein thrombosis and pulmonary embolism. Pharmacologic VTE prophylaxis is a critical component of optimal trauma care that significantly decreases VTE risk. Optimal VTE prophylaxis protocols must manage the risk of VTE with the competing risk of hemorrhage in patients following significant trauma. Currently, there is variability in VTE prophylaxis protocols across trauma centers. In an attempt to optimize VTE prophylaxis for the injured patient, stakeholders from the American Association for the Surgery of Trauma and the American College of Surgeons-Committee on Trauma collaborated to develop a group of consensus recommendations as a resource for trauma centers. The primary goal of these recommendations is to help standardize VTE prophylaxis strategies for adult trauma patients (age ≥15 years) across all trauma centers. This clinical protocol has been developed to (1) provide standardized medication dosing for VTE prophylaxis in the injured patient; and (2) promote evidence-based, prompt VTE prophylaxis in common, high-risk traumatic injuries.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level V.

The emerging therapeutic potential of extracellular vesicles in trauma

Traumatic injury is a major cause of morbidity and mortality worldwide, despite significant advances in treatments. Most deaths occur either very early, through massive head trauma/CNS injury or exsanguination (despite advances in transfusion medicine), or later after injury often through multiple organ failure and secondary infection. Extracellular vesicles (EVs) are known to increase in the circulation after trauma and have been used to limited extent as diagnostic and prognostic markers. More intriguingly, EVs are now being investigated as both causes of pathologies post trauma, such as trauma-induced coagulopathy, and as potential treatments. In this review, we highlight what is currently known about the role and effects of EVs in various aspects of trauma, as well as exploring current literature from investigators who have begun to use EVs therapeutically to alter the physiology and pathology of traumatic insults. The potential effectiveness of using EVs therapeutically in trauma is supported by a large number of experimental studies, but there is still some way to go before we understand the complex effects of EVs in what is already a complex disease process.

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.

Personalized modulation of coagulation factors using a thrombin dynamics model to treat trauma-induced coagulopathy

Current trauma-induced coagulopathy resuscitation protocols use slow laboratory measurements, rules-of-thumb, and clinician gestalt to administer large volumes of uncharacterized, non-tailored blood products. These one-size-fits-all treatment approaches have high mortality. Here, we provide significant evidence that trauma patient survival 24 h after hospital admission occurs if and only if blood protein coagulation factor concentrations equilibrate at a normal value, either from inadvertent plasma-based modulation or from innate compensation. This result motivates quantitatively guiding trauma patient coagulation factor levels while accounting for protein interactions. Toward such treatment, we develop a Goal-oriented Coagulation Management (GCM) algorithm, a personalized and automated ordered sequence of operations to compute and specify coagulation factor concentrations that rectify clotting. This novel GCM algorithm also integrates new control-oriented advancements that we make in this work: an improvement of a prior thrombin dynamics model that captures the coagulation process to control, a use of rapidly-measurable concentrations to help predict patient state, and an accounting of patient-specific effects and limitations when adding coagulation factors to remedy coagulopathy. Validation of the GCM algorithm's guidance shows superior performance over clinical practice in attaining normal coagulation factor concentrations and normal clotting profiles simultaneously.

A nested case-control study of risk for pulmonary embolism in the general trauma population using nationwide trauma registry data in Japan

Post-trauma patients are at great risk of pulmonary embolism (PE), however, data assessing specific risk factors for post-traumatic PE are scarce. This was a nested case–control study using the Japan Trauma Data Bank between 2004 and 2017. We enrolled patients aged ≥ 16 years, Injury Severity Score ≥ 9, and length of hospital stay ≥ 2 days, with PE and without PE, using propensity score matching. We conducted logistic regression analyses to examine risk factors for PE. We included 719 patients with PE and 3595 patients without PE. Of these patients, 1864 [43.2%] were male, and their median Interquartile Range (IQR) age was 73 [55–84] years. The major mechanism of injury was blunt (4282 [99.3%]). Median [IQR] Injury Severity Score (ISS) was 10 [9–18]. In the multivariate analysis, the variables spinal injury [odds ratio (OR), 1.40 (1.03–1.89)]; long bone open fracture in upper extremity and lower extremity [OR, 1.51 (1.06–2.15) and OR, 3.69 (2.89–4.71), respectively]; central vein catheter [OR, 2.17 (1.44–3.27)]; and any surgery [OR, 4.48 (3.46–5.81)] were independently associated with PE. Spinal injury, long bone open fracture in extremities, central vein catheter placement, and any surgery were risk factors for post-traumatic PE. Prompt initiation of prophylaxis is needed for patients with such trauma.

Burn-Induced Coagulopathies: a Comprehensive Review

Burn-induced coagulopathy is not well understood, and consensus on diagnosis, prevention, and treatments are lacking. In this review, literature on burn-induced (and associated) coagulopathy is presented along with the current understanding of the effects of burn injury on the interactions among coagulation, fibrinolysis, and inflammation in the acute resuscitative phase and reconstructive phase of care. The role of conventional tests of coagulopathy and functional assays like thromboelastography or thromboelastometry will also be discussed. Finally, reported methods for the prevention and treatment of complications related to burn-induced coagulopathy will be reviewed.

The incidence and risk factors of deep venous thrombosis in lower extremities following surgically treated femoral shaft fracture: a retrospective case-control study

Background

There is still a lack of data on deep vein thrombosis (DVT) following surgically treated femoral shaft fracture (FSF). The goal of this study was to investigate the characteristics of postoperative DVT and the association between the occurrence of DVT and risk factors in patients undergoing surgical treatment for FSF.

Methods

This observational retrospective case-control study reviewed 308 patients who received surgical treatment of FSF between January 2016 and October 2020 at a university hospital. Univariate analyses were performed on the data of demographics, comorbidities, laboratory biomarkers, and operation-related indexes. The receiver operating characteristic (ROC) curve analysis, univariate analyses, and multivariate logistic regression analysis were employed to identify the independent risk factors associated with DVT.

Results

In total, 308 patients with surgically treated FSF were included, among whom 48 (15.6%) patients had postoperative DVTs. The univariate analyses showing significant differences regarding DVT were American Society of Anesthesiologists (ASA) classification, diabetes mellitus, current smoking, aspartate transaminase (AST), and very-low-density lipoprotein (VLDL) level among the 34 factors. According to the ROC results, the optimal cutoff values for intraoperative blood loss, d-dimer, and age were 350 ml, 1.08 μg/ml, and 35 years, respectively. The multivariable model demonstrated 4 significantly independent associations with postoperative DVT, including current smoking, intraoperative blood loss (> 550 ml), age (> 35 years), and d-dimer > 1.09 μg/ml.

Conclusion

These risk factors as screening tools contribute to risk stratification of the occurrence of thromboembolic events. In addition, our findings would help orthopedic surgeons make a cross-specialty decision and implement targeted precaution measures for patients with FSF.

Alternative Complement Pathway Activation Provokes a Hypercoagulable State with Diminished Fibrinolysis

INTRODUCTION

Several disease processes trigger prolonged activation of the alternative complement pathway. Crosslinks between complement activation and physiologic changes in platelets and neutrophils have been identified, but how this interplay alters the hemostatic potential in humans remains undefined. We hypothesize that activation of the alternative pathway triggers a hypercoagulable state.

METHODS

C3/C5 convertase Cobra Venom Factor (CVF, 10 Units/mL) was employed to activate the alternative complement pathway in whole blood. Complement inhibition was completed with inhibitors for C3/C3b (Compstatin, 25 and 50 μM), C3a receptor (SB290157, 300 nM, C3aR), and C5a receptor (W54011, 6 nM, C5aR). Coagulation was assessed using native thrombelastography which produces the following: reaction time (R time); angle; maximum amplitude (MA); percent fibrinolysis at 30-min post-MA (LY30).

RESULTS

Inhibition with C3aR and C5aR inhibitors did not alter clot formation (R time, 11.2 vs 11.6 min, P = 0.36), clot strength (MA, 52.0 vs 52.3 mm, P = 0.43), or fibrinolysis (LY30, 1.6 vs 4.0%, P = 0.19). Compstatin did not influence clot formation or clot strength but did induce a dose-dependent increase in fibrinolysis (control LY30 3.0 vs 7.8% and 12.4% for 25 and 50 μM respectively, P = 0.0002). CVF increased MA (58.0 vs 62.8 mm, P < 0.0001), decreased LY30 (2.3 vs 1.4%, P = 0.004), and increased R time (8.4 vs 9.9 min, P = 0.008). Compstatin reversed the effects of CVF, while C5a reversed only the change in LY30.

CONCLUSIONS

C3 contributes to fibrinolysis, as inhibition with Compstatin enhanced fibrinolysis, and CVF cleavage of C3 decreased fibrinolysis. CVF also induced a hypercoagulable state with increased clot strength.

Venous Thromboembolism in Trauma: The Role of Anticoagulation and Inferior Vena Cava Filters

Venous thromboembolism (VTE) is a significant contributor to morbidity and mortality among patients with severe trauma. Historically, prophylactic inferior vena cava filters (IVCFs) were used in high-risk trauma patients with suspected risk factors for VTE, including prolonged immobilization, and concurrent contraindication to anticoagulation. Mounting data regarding the efficacy of IVCF in this cohort, as well as concerns regarding morbidity of an in situ IVCF, have challenged this practice paradigm. In this review, we discuss the comanagement of VTE and trauma, including anticoagulation and the use of IVCF.

The Incidence and Location of Deep Vein Thrombosis in Lower Extremity Fracture Patients Receiving Sequential Chemical Prophylaxis

To investigate the incidence and location of deep vein thrombosis (DVT) in patients with lower extremity fractures receiving pharmacological thromboprophylaxis with LMWH followed by rivaroxaban. All patients aged ≥18 years with lower extremity fractures were included in the study. Duplex ultrasonography (DUS) was performed in the lower extremities before and after surgery for DVT evaluation. According to the location, the DVT was divided into proximal, distal, and mixed thromboses. According to fracture location, patients were classified as having fractures proximal, around, and distal to the knee. All patients received sequential chemical prophylaxis. A total of 404 patients with a mean age of 44.2 ± 13.8 years were included. The incidence of DVT postoperatively was higher than that preoperatively and at 1 month postoperatively. Patients with fractures proximal and around the knee had higher DVT incidences detected on DUS postoperatively and at 1 month postoperatively. Most DVTs were located in the distal vein. DVT incidence and severity were the highest immediately after surgery. DVT incidence in fractures around and proximal to the knee increased after surgery and at 1 month postoperatively. Although with chemical thromboprophylaxis, distal DVT was the most variable during the early stage.

Trauma magnitude of the meta-epyphyseal cancellous affects the incidence of deep vein thrombosis. A prospective cohort study on the dynamic of Collagen I, Collagen IV, Tissue factor, P-Selectin and Nitric Oxide in the thrombus formation following hip and knee surgeries

INTRODUCTION

The purpose of this study was to analyze the traumatization degree of meta-epiphyseal cancellous of hip and knee joints in major orthopedic surgery that affects the incident of deep vein thrombosis (DVT) event through the dynamics expression of pro-thrombogenic biomarkers (Collagen I, Collagen IV, Tissue Factor, P-selectin) and anti-thrombogenic (Nitric Oxide).

METHODS

In this cohort prospective study, there were sixty-nine (69) subjects that were divided into three (3) groups, with twenty-three (23) subjects that were treated with total arthroplasty (TA), twenty-two (22) subjects were treated with hemiarthroplasty (HA), twenty-four (24) subjects were treated with open reduction internal fixation (ORIF). Subjects from May 2010 to September 2011 who met the inclusion criteria were included in this study. All patients were treated without thromboprophylaxis. Blood samples were taken in three different periods, before surgery, 72 h, and 144 h after surgery, for examination of pro-thrombogenic biomarkers (Collagen I, Collagen IV, Tissue Factor, P-selectin) and anti-thrombogenic (Nitric Oxide), which are the components involved in the hemostasis.

RESULTS

DVTs were proven by venography (or Doppler ultrasound in 8 cases) done at 144 h after the surgeries. Eighteen (18) subjects had DVT (26.1%), with ten (10) subjects from the TA group (43.5%), five (5) subjects from the HA group (22.7%), and three (3) subjects from ORIF groups (12.5) %). The risk for experiencing DVT on TA is 3.5 times more than the ORIF group, while in HA group is 2.1 times more than ORIF group. The role of biomarker levels on DVT incidence was found in Col I (p < 0.1) and NO (p < 0.05) at 72 h after surgery.

CONCLUSION

This research confirms that trauma magnitude of the meta-epiphyseal cancellous of hip and knee joints in major orthopedic surgery influences the incidence of DVTs, through the elevation of Col I and NO. An estimated 72 h after surgery is a useful period to examine these biomarkers to help predict the diagnose of DVT. The involvement of the other biomarkers studied (Col IV, TF, and Ps) could not be proven. Future studies are needed to evaluate other biomarkers in the complex process of hemostasis to establish the diagnose of DVT.

Whole Blood Thrombin Generation in Severely Injured Patients Requiring Massive Transfusion

BACKGROUND

Despite the prevalence of hypocoagulability after injury, the majority of trauma patients paradoxically present with elevated thrombin generation (TG). Although several studies have examined plasma TG post injury, this has not been assessed in whole blood. We hypothesize that whole blood TG is lower in hypocoagulopathy, and TG effectively predicts massive transfusion (MT).

STUDY DESIGN

Blood was collected from trauma activation patients at an urban Level I trauma center. Whole blood TG was performed with a prototype point-of-care device. Whole blood TG values in healthy volunteers were compared with trauma patients, and TG values were examined in trauma patients with shock and MT requirement.

RESULTS

Overall, 118 patients were included. Compared with healthy volunteers, trauma patients overall presented with more robust TG; however, those arriving in shock (n = 23) had a depressed TG, with significantly lower peak thrombin (88.3 vs 133.0 nM; p = 0.01) and slower maximum rate of TG (27.4 vs 48.3 nM/min; p = 0.04). Patients who required MT (n = 26) had significantly decreased TG, with a longer lag time (median 4.8 vs 3.9 minutes, p = 0.04), decreased peak thrombin (median 71.4 vs 124.2 nM; p = 0.0003), and lower maximum rate of TG (median 15.8 vs 39.4 nM/min; p = 0.01). Area under the receiver operating characteristics (AUROC) analysis revealed lag time (AUROC 0.6), peak thrombin (AUROC 0.7), and maximum rate of TG (AUROC 0.7) predict early MT.

CONCLUSIONS

These data challenge the prevailing bias that all trauma patients present with elevated TG and highlight that deficient thrombin contributes to the hypocoagulopathic phenotype of trauma-induced coagulopathy. In addition, whole blood TG predicts MT, suggesting point-of-care whole blood TG can be a useful tool for diagnostic and therapeutic strategies in trauma.

Perioperative Deep Vein Thrombosis in Patients With Lower Extremity Fractures: An Observational Study

This study aimed to investigate deep vein thrombosis (DVT) in patients with lower extremity fractures who received anticoagulation treatment in the perioperative stage. We collected the patients’ clinical data and diagnosed DVT using Doppler ultrasonography. Preoperative, postoperative, and 1-month postoperative examinations were performed. The patients were divided into thrombosis and non-thrombosis groups according to ultrasonographic findings. A total of 404 patients were included in the study. The preoperative, postoperative, and 1-month postoperative incidence rates were, respectively, 35%, 55%, and 40% for DVT and 12%, 22%, and 20% for DVT in the uninjured contralateral lower extremity. The incidence of perioperative DVT decreased over time from 223 (55%) to 161 (40%). Multivariate analysis revealed that the independent risk factors for preoperative that of DVT were age (odds ratio [OR]: 1.03; 95% CI: 1.01-1.04; P = .000); postoperative that of DVT were age (OR: 1.04; 95% CI: 1.03-1.05; P = .000), blood loss (OR: 1.001; 95% CI: 1.000-1.002; P = .018), and American Society of Anesthesiologists classification (OR: 2.07; 95% CI: 1.16-3.72; P = .014); and 1-month postoperative that of DVT were age (OR: 1.05; 95% CI: 1.03-1.07; P = .000), respectively. In conclusion, the incidence of perioperative DVT decreased over time in patients who received anticoagulation treatment. Age was an important risk factor for perioperative DVT.

Deep Vein Thrombosis in the Uninjured Lower Extremity: A Retrospective Study of 1454 Patients With Lower Extremity Fractures

The purpose of this study was to identify patients at higher risk of deep venous thrombosis (DVT) in the uninjured lower extremity both preoperatively and postoperatively in patients with lower extremity fractures. We collected the clinical data of patients with lower extremities fractures who presented at Xi’an Honghui Hospital between 1 July, 2015 and 31 October, 2017. Doppler ultrasonography was used to diagnose the DVT. Patients were examined pre- and postoperatively. The patients were divided into thrombosis group and no thrombosis group according to the preoperative and postoperative ultrasonography results. The thrombosis group was defined as patients with DVT in the uninjured lower extremity and the no thrombosis group was defined as patients without DVT in the uninjured lower extremity. This study enrolled 1454 patients who met the inclusion criteria. The incidence of preoperative DVT in the uninjured lower extremity was 9.63% whereas the postoperative incidence was 20.29%. Age (OR = 0.965, 95 CI%: 0.954-0.977; P ≤ 0.001) and female (OR = 0.667, 95% CI: 0.451-0.986, P = 0.042) were independent risk factors for preoperative DVT in the uninjured lower extremity. Blood loss (OR = 0.997, 95 CI%: 0.995-1.000; P = 0.020), D-dimer level at admission (OR = 0.941, 95 CI%: 0.887-0.999; P = 0.045), and postoperative day 5 D-dimer level (OR = 0.889, 95 CI%: 0.819-0.965; P = 0.005), were independent risk factors for postoperative DVT in the uninjured lower extremity. For the patients with lower extremity fractures, age and female were associated with the preoperative DVT in the uninjured lower extremity. Blood loss, D-dimer at admission and postoperative day 5 D-dimer were associated with the postoperative DVT in the uninjured lower extremity.

Epidural catheters are associated with an increased risk of venous thromboembolism in trauma

Little is known about the association between epidural catheters (EC) and venous thromboembolism (VTE) in trauma. We sought to study this association and hypothesized that trauma patients with EC were more likely to develop VTE. Using the Pennsylvania Trauma Outcomes Study (PTOS) registry, we identified all adult trauma patients (age ≥ 18) admitted for at least 2 days between 1/2013 and 12/2017. Baseline characteristics and outcome variables were compared between patients who underwent EC placement and those who did not. The primary outcome was development of VTE. 147,721 patients met inclusion criteria; 2247 (1.5%) developed a VTE. Patients were mostly white (85%), male (56%), with blunt trauma (94%). 776 (0.5%) had an EC placed. Patients who underwent EC placement were more likely to develop a VTE (2.8% vs. 1.5%, p = 0.003). After adjusting for covariates, patients with EC were 1.6 times more likely to develop VTE (95% CI 1.1-2.5). The overall rate of VTE was low and associated with the use of EC. Future work should focus on determining the underlying mechanisms.

Post-operative deep vein thrombosis in patients over sixty years of age diagnosed with closed distal femur fractures undergoing open reduction internal fixation

BACKGROUND AND PURPOSE

New-onset deep vein thrombosis (DVT) reportedly affects prognosis and surgical outcomes of elderly patients. However, its effect on distal femur fractures (DFFs) remains unclear. We aimed to address the epidemiological characteristics and the associated predictors for post-operative DVT in patients with closed DFFs over age 60 years old.

PATIENTS AND METHODS

We designed a prospective cohort trial at our hospital between October 2018 and June 2020 and recruited consecutive 140 patients over age 60 years diagnosed with closed DFFs. We examined location and prognosis of postoperative DVT and then conducted a three month follow-up. We used Duplex ultrasonography (DUS) to diagnose DVT in all patients and then classified the subjects into DVT and non-DVT groups. We further classified DVTs into proximal, distal, and mixed thromboses and then performed Whitney U test or t test, receiver operating characteristic (ROC) curve analysis, Chi-square test, and multiple logistic regression analysis to confirm the adjusted factors of post-operative DVT.

RESULTS

We found a 35% (n = 49) overall incidence of post-operative DVTs, which occurred 5.7 days following open reduction internal fixation (ORIF). Among patients with post-operative DVTs, 53.1% (n = 26) and 10.2% (n = 5) were distal and proximal thromboses, respectively. Additionally, peroneal veins were the most common DVT sites (71.4%, n = 35). Multivariate analysis revealed that venous thrombosis at admission (odds ratio [OR], 4.619; 95% confidence interval [CI]: 2.072-10.299; P = 0.000), operation duration over 195 minutes (OR, 3.289; 95% CI, 1.155-9.370; P = 0.026), intra-operative blood loss over 325 mL (OR, 2.538; 95% CI, 1.047-6.155; P = 0.039) were the three independent risk factors of post-operative DVT. Unified antithrombotic agents after diagnosis showed that 16.3% (n = 8) of DVTs were completely recanalized, 12.6 days after first diagnosis.

CONCLUSION

Our findings indicate a strong association between venous thrombosis at admission, the longer operation duration, and considerable intra-operative blood loss with high risk of post-operative DVTs in patients over age 60 years with closed DFFs. Preventive approaches for postoperative DVTs should seek to shorten operation duration and reduce intra-operative blood loss.

Clinical Characteristics Associated With Higher Enoxaparin Dosing Requirements for Venous Thromboembolism Prophylaxis in Trauma Patients

INTRODUCTION

Enoxaparin dosed by an anti-Xa trough level is effective at reducing venous thromboembolism (VTE) in trauma patients. We identified the patient characteristics associated with higher enoxaparin dosing based on anti-Xa trough levels.

METHODS

A retrospective review was conducted on trauma patients admitted between August 2014 and February 2018 who received enoxaparin dosed by the anti-Xa trough level. Patients who received enoxaparin < 50 mg every 12 hours were compared to those who required ≥ 50 mg every 12 hours.

RESULTS

Of the 246 patients included, 32 (13.0%) required enoxaparin ≥ 50 mg every 12 hours to achieve the prophylactic trough level. Factors associated with a higher dose of enoxaparin were male (96.8% vs. 3.2%, P < .01), younger age (39.5 vs. 52.7 years, P < .01), higher creatinine clearance (CrCl) (125.9 vs. 93.7 mL/min, P < .01), higher body surface area (2 m² vs. 1.8 m², P < .01), and higher injury severity score (18.4 vs. 10.8, P < .01). Height, weight, and body mass index were not significant factors. On regression analysis, CrCl was the only independent predictor for higher enoxaparin dose. There was an increased deep venous thrombosis rate in the higher dose cohort (12.5% vs. 0, P < .01) but no significant differences in transfusion rates.

CONCLUSION

Trauma patients who require higher enoxaparin doses to achieve prophylactic anti-Xa trough levels have a higher CrCl. Patients with high CrCl may benefit from an initial higher dose of enoxaparin to achieve a target anti-Xa level in a shorter time interval to decrease VTE risk.

Free tissue transfer with supermicrosurgical perforator-to-perforator (P-to-P) technique for tissue defect reconstruction around the body: Technical pearls and clinical experience

BACKGROUND

Resorting to perforators as recipient vessels is a valid alternative that might offer a series of advantages in many situations. They allow the use of a shorter pedicle, reduce the time of dissection, and are a good solution when deep vessels are difficult to reach. The aim of this study is to investigate the efficacy of P-to-P tissue transfer for reconstructing defects in different areas of the body.

PATIENTS AND METHODS

Between April 2018 and February 2020, 40 patients presenting soft tissue defects were reconstructed by using P-to-P-anastomosed free flap transfer. The cause of the defect was trauma in 16 cases and surgically excised tumor in 24. Five defects were located in the upper extremities, 1 in the neck, 1 in the thorax, and 21 in the lower limb, and 13 cases were breast reconstructions, 2 of which bilateral (43 total flaps).

RESULTS

Of all 43 flaps, 22 were abdominal flaps, 17 flaps were harvested from the upper thigh, and 4 were harvested from the lower leg. At the 9 month follow-up, 42 flaps were successfully healed, 36 without complications, 3 after wound dehiscence, and 3 after wound infection, and only 1 flap was lost requiring further surgery. Flap failure rate was 2.3%.

CONCLUSIONS

Free flaps anastomosed in perforator-to-perforator fashion can be safely used in different settings throughout the body. Even if they are technically more demanding, they may allow a quicker operation time and lower morbidity. With the developments in microsurgical instruments, we believe that this technique may become the gold standard for tissue-defect reconstruction.

How to Safely Prevent Venous Thromboembolism in Severe Trauma Patients

Venous thromboembolism (VTE) is a life-threatening complication after trauma. Several studies have reported VTE prophylaxis using low-molecular-weight heparin; however, there is no consensus for prophylaxis after trauma. This study aimed to assess the efficacy and safety of our new anticoagulation therapy protocol using unfractionated heparin (UFH) plus intermittent pneumatic compression (IPC) to prevent post-traumatic VTE in high-risk trauma patients.This study enrolled 70 trauma patients who were admitted to the emergency medical center of Nagasaki University Hospital and had Risk Assessment Profile (RAP) scores ≥ 5. After stopping bleeding at the trauma site, all patients received intravenous UFH (10,000 U/day) plus IPC, which was continued for 14 days or until the patients could walk. On days 7 and 14, all patients underwent lower extremity sonography for deep-vein thrombosis screening. VTE incidences between patients with the above intervention and historical controls with IPC alone were compared.No significant differences in age, sex, and the RAP score were observed between the 105 controls and intervention patients. VTE occurrence was fewer in patients with the intervention (14.3%) than in the controls (28.6%; P = 0.029). No hemorrhagic complications occurred after UFH administration. Multivariable logistic analysis revealed a significant association between the intervention and low incidence of VTE (odds ratio: 0.390; 95% confidence interval: 0.163-0.913; P = 0.030).Routine UFH administration with IPC may prevent post-traumatic VTE without adverse events.

Deep vein thrombosis in the lower extremities after femoral neck fracture: A retrospective observational study

PURPOSE

The actual incidence of deep vein thrombosis (DVT) in femoral neck fractures is underestimated. This study aimed to investigate the incidence of DVT in the lower extremities after femoral neck fracture before and after operation.

METHODS

The clinical data of patients with femoral neck fractures treated at Xi'an Honghui Hospital between July 1, 2016, and December 31, 2018, were collected. The patients were examined with ultrasonography before and after operation and divided into thrombosis and non-thrombosis groups according to their ultrasonographic results. The incidence of DVT was reported as a percentage.

RESULTS

The incidence rates of preoperative and postoperative DVT were 32% and 56%, respectively. DVT on the uninjured side constituted 45% of all preoperative DVT and 43% of all postoperative DVT. Peripheral DVT constituted 90% and 84% of all preoperative and postoperative DVT, respectively. Diabetes was an independent risk factor of preoperative DVT. Blood loss was an independent risk factor of postoperative DVT, and open reduction and internal fixation surgical procedure was independent protective factor of postoperative DVT as compared with hemiarthroplasty and total hip replacement.

CONCLUSIONS

The incidence rates of preoperative and postoperative DVT in the patients with femoral neck fracture were high, and orthopedists should pay more attention to DVT as a complication.

Deep Vein Thrombosis in Patients with Intertrochanteric Fracture: A Retrospective Study

BACKGROUND

This study aimed to investigate the incidences of pre- and post-operative lower extremity deep venous thrombosis (DVT) in hospitalized patients with intertrochanteric fractures and to analyze the relevant risk factors.

METHODS

A retrospective study was conducted between July 2014 and October 2016 in 218 intertrochanteric fracture patients who presented at Xi'an Honghui Hospital and underwent Doppler ultrasonography for DVT diagnosis. We divided DVT into distal, proximal, and mixed thrombosis. Patients were divided into either the thrombosis or no thrombosis group according to preoperative and postoperative ultrasonography results. All patients were evaluated for the risk factors associated with thrombosis.

RESULTS

A total of 37.61% of preoperative patients had DVT, and the postoperative incidence increased to 58.72%. The days between fracture and hospitalization and the days between fracture and surgery were independent risk factors for preoperative DVT. The days between fracture and hospitalization and d-dimer levels at postoperative 1 day were independent risk factors of postoperative DVT. In total 23.4% of the patients progressed from having no thrombosis preoperatively to having distal, proximal, or mixed DVT postoperatively (22.02%, 0.46%, and 0.92%, respectively). Distal DVT constituted 86.59% and 90.63% of all preoperative and postoperative DVTs, respectively.

CONCLUSION

Intertrochanteric fracture is a common type of hip fracture in the elderly, and the incidence of DVT after intertrochanteric fracture may be underestimated. Early intervention (early admission and early surgery) might reduce the incidence of DVT.

Early Chemoprophylaxis in Severely Injured Trauma Patients Reduces Risk of Venous Thromboembolism

BACKGROUND

Venous thromboembolism (VTE) remains a serious complication for trauma patients. While early VTE prophylaxis has gained traction, the timing of prophylaxis remains uncertain. We hypothesized that VTE prophylaxis within 24 hours of admission would have lower VTE rates and similar rates of adverse events in seriously injured patients.

METHODS

Trauma patients were included from 32 American College of Surgeons verified Level 1 and 2 trauma centers over a 10-year period. Patients with injury severity score (ISS) <15, death or discharge within 48 hours of arrival, or who received no prophylaxis were excluded.

RESULTS

14 096 patients received VTE prophylaxis with an ISS of ≥15. Patients given prophylaxis at <24 hours had fewer VTE events and trended toward fewer serious in-hospital complications. Mortality and return to the operating room were similar across groups. Hospital and intensive care unit length of stay in the <24 hours prophylaxis group was significantly shorter when VTE prophylaxis was initiated earlier.

CONCLUSIONS

In severely injured trauma patients with ISS >15, early VTE prophylaxis within 24 hours significantly reduced the risk of VTE as compared with delayed prophylaxis. Early chemoprophylaxis was found to be efficacious in reducing the incidence of VTE; however, the safety of this practice should be evaluated by future prospective studies.

Thromboelastometry for Assessing Risks of Free Flap Thrombosis in Patients Undergoing Microvascular Surgery

Introduction: Coagulation assessment is often missing in microvascular surgery. We aimed at evaluating the predictive value of thromboelastometry for free flap thrombosis in microvascular surgery patients. Materials and Methods: We enrolled 103 adult patients with traumatic injuries scheduled for microvascular free flap surgery into a prospective observational study. Thirty-six patients with recent trauma underwent surgery within 30 days (ES group), and were compared with 67 trauma patients who underwent surgery later than 30 days (late surgery, LS group) after the injury. Rotational thromboelastometry (RTE) was performed before surgery. Functional fibrinogen to platelet ratio (FPR) ≥ 42 was selected as the main hypercoagulability index. Free flap thrombosis was set as primary outcome. Thrombotic risk factors and duration of surgery related to free flap thrombosis were secondary outcomes. Statistical significance p < 0.05; not significant NS. Results: Six patients (16.7%) in the ES group and 10 (14.9%) in the LS group had free flap thrombosis (NS). In the entire cohort, free flap thrombosis rate increased in the presence of thrombogenic comorbidities (OR 4.059, CI 1.33-12.37; p = 0.014) and prolonged surgery times (OR 1.007, CI 1 - 1.012; p = 0.05). Although hypercoagulability occurred more frequently in the ES group (44.4%) than in the LS group (11.9%; p < 0.001), it was not associated with higher free flap thrombosis rate. In ES group patients with surgery times > 240 min, the risk of free flap thrombosis increased (OR 3.5, CI 1.16-10.6; p = 0.026) with 93.3% sensitivity and 86.7% specificity (AUC 0.85; p = 0.007). In contrast, in LS patients hypercoagulability increased the odds of free flap thrombosis (OR 8.83, CI 1.74-44.76; p = 0.009). Moreover, a positive correlation was found between FPR ≥ 42 and free flap thrombosis rate (r = 0.362; p = 0.003). In the LS group, the presence of thrombogenic comorbidities correlated with free flap thrombosis rate (OR 7, CI 1.591-30.8; p = 0.01). Conclusions: In LS patients with thrombogenic comorbidities, thromboelastometry supports the detection of hypercoagulability and predicts free flap thrombosis risk. In ES patients, postoperative hypercoagulability did not predict free flap thrombosis. Prolonged surgery time should be considered as a risk factor.

MSC Therapies for COVID-19: Importance of Patient Coagulopathy, Thromboprophylaxis, Cell Product Quality and Mode of Delivery for Treatment Safety and Efficacy

Numerous clinical trials of mesenchymal stromal/stem cells (MSCs) as a new treatment for coronavirus-induced disease (COVID-19) have been registered recently, most of them based on intravenous (IV) infusion. There is no approved effective therapy for COVID-19, but MSC therapies have shown first promise in the treatment of acute respiratory distress syndrome (ARDS) pneumonia, inflammation, and sepsis, which are among the leading causes of mortality in COVID-19 patients. Many of the critically ill COVID-19 patients are in a hypercoagulable procoagulant state and at high risk for disseminated intravascular coagulation, thromboembolism, and thrombotic multi-organ failure, another cause of high fatality. It is not yet clear whether IV infusion is a safe and effective route of MSC delivery in COVID-19, since MSC-based products express variable levels of highly procoagulant tissue factor (TF/CD142), compromising the cells' hemocompatibility and safety profile. Of concern, IV infusions of poorly characterized MSC products with unchecked (high) TF/CD142 expression could trigger blood clotting in COVID-19 and other vulnerable patient populations and further promote the risk for thromboembolism. In contrast, well-characterized products with robust manufacturing procedures and optimized modes of clinical delivery hold great promise for ameliorating COVID-19 by exerting their beneficial immunomodulatory effects, inducing tissue repair and organ protection. While the need for MSC therapy in COVID-19 is apparent, integrating both innate and adaptive immune compatibility testing into the current guidelines for cell, tissue, and organ transplantation is critical for safe and effective therapies. It is paramount to only use well-characterized, safe MSCs even in the most urgent and experimental treatments. We here propose three steps to mitigate the risk for these vulnerable patients: (1) updated clinical guidelines for cell and tissue transplantation, (2) updated minimal criteria for characterization of cellular therapeutics, and (3) updated cell therapy routines reflecting specific patient needs.