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.

Viscoelastic Testing and Coagulopathy of Traumatic Brain Injury

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

"Death Diamond" Tracing on Thromboelastography as a Marker of Poor Survival After Trauma

BACKGROUND

Improvements in health care innovations have resulted in an enhanced ability to extend patient viability. As a consequence, resources are being increasingly utilized at an unsustainable level. As we implement novel treatments, identifying futility should be a focus. The "death diamond" (DD) is a unique thrombelastography (TEG) tracing that is indicative of failure of the coagulation system, with a mortality rate exceeding 90%. The purpose of this study was to determine if the DD was a consistent marker of poor survival in a multicenter study population. We hypothesize that the DD, while an infrequent occurrence, predicts poor survival and can be used to stratify patients in whom resuscitation efforts are futile.

METHODS

A retrospective multi-institutional study of trauma patients presenting with TEG DDs between 8/2008 and 12/2018 at four American College of Surgeons trauma centers was completed. Demographics, injury mechanisms, TEG results, management, and survival were examined.

RESULTS

A total of 50 trauma patients presented with DD tracings, with a 94% (n = 47) mortality rate. Twenty-six (52%) patients received a repeat TEG with 10 patients re-demonstrating the DD tracing. There was 100% mortality in patients with serial DD tracings. The median use of total blood products was 18 units (interquartile range 6, 34.25) per patient.

DISCUSSION

The DD is highly predictive of trauma-associated mortality. This multicenter study highlights that serial DDs may represent a possible biomarker of futility.

Diagnosis and Treatment of Trauma-Induced Coagulopathy by Viscoelastography

This article explores the application of viscoelastic tests (VETs) in trauma-induced coagulopathy and trauma resuscitation. We describe the advantages of VETs over conventional coagulation tests in the trauma setting and refer to previous disciplines in which VET use has reduced blood product utilization, guided prohemostatic agents, and improved clinical outcomes such as the mortality of critically bleeding patients. We describe different VETs and provide guidance for blood component therapy and prohemostatic therapy based on specific VET parameters. Because the two most commonly used VET systems, rotational thromboelastometry and thromboelastography, use different activators and have different terminologies, this practical narrative review will directly compare and contrast these two VETs to help the clinician easily interpret either and use the interpretation to determine hemostatic integrity in the bleeding trauma patient. Finally, we anticipate the future of new viscoelastic technologies that can be used in this setting.

The “Death Diamond”: Death beyond Trauma

Thromboelastography (TEG) has become a critical tool for the diagnosis, assessment, and management of hyperfibrinolysis and coagulopathy in trauma. In 2015, Chapman et al. of the Denver group coined the term “Death Diamond” (DD) to describe a TEG tracing identified in a unique trauma population. The DD was associated with a 100 per cent positive predictive value for mortality. Given the potential prognostic implications and resource savings associated with validating the DD as a marker of futile care, we sought to further evaluate DD outcomes. A retrospective review of 6850 TEGs, 34 patients (24 trauma and 10 nontrauma), displayed a DD tracing. Through invasive procedures and transfusions, nine DD tracing “normalized,” but, ultimately, this did not impact the outcome because the DD had a positive predictive value of 100 per cent for mortality in both populations. The median survival time in trauma patients was two hours compared with seven hours in nontrauma patients. Overall, this study further validates the predictive value of the DD in a trauma population while also serving as an assessment of the DD in a nontrauma population. Given these findings, a DD may prove to be an indicator of futile care. Further multicenter studies should be conducted to confirm these results.

The "Death Diamond": Death Beyond Trauma

Thromboelastography (TEG) has become a critical tool for the diagnosis, assessment, and management of hyperfibrinolysis and coagulopathy in trauma. In 2015, Chapman et al. of the Denver group coined the term "Death Diamond" (DD) to describe a TEG tracing identified in a unique trauma population. The DD was associated with a 100 per cent positive predictive value for mortality. Given the potential prognostic implications and resource savings associated with validating the DD as a marker of futile care, we sought to further evaluate DD outcomes. A retrospective review of 6850 TEGs, 34 patients (24 trauma and 10 nontrauma), displayed a DD tracing. Through invasive procedures and transfusions, nine DD tracing "normalized," but, ultimately, this did not impact the outcome because the DD had a positive predictive value of 100 per cent for mortality in both populations. The median survival time in trauma patients was two hours compared with seven hours in nontrauma patients. Overall, this study further validates the predictive value of the DD in a trauma population while also serving as an assessment of the DD in a nontrauma population. Given these findings, a DD may prove to be an indicator of futile care. Further multicenter studies should be conducted to confirm these results.

Cross-Sectional and Longitudinal Association Between Antihypertensive Medications and Cognitive Impairment in an Elderly Population

BACKGROUND

The effect of antihypertensive medications on cognitive function has not been well studied. The authors' objectives were to investigate the cross-sectional and longitudinal association between the use of antihypertensive medications and cognitive function and to compare different antihypertensive medication classes with regard to this association in an elderly population.

METHODS

The medical records of a convenience sample of patients (n = 993 cross-sectional and 350 longitudinal; mean age, 76.8 +/- 0.3 years; 74% women; 87% White) followed at a geriatric practice were reviewed. Data abstracted included demographics, medical history (Alzheimer's disease [AD] or vascular dementia [VaD]), use of antihypertensive medications, and results of cognitive assessments (the Mini-Mental Status Examination [MMSE] and the Clock Draw Test [CDT]).

RESULTS

In the cross-sectional analysis, antihypertensive use was not associated with MMSE (p >.05), CDT (p >.05), or dementia diagnosis (odds ratio for AD, 0.8; 95% confidence interval [CI], 0.6 to 1.2; odds ratio for VaD, 1.6; 95% CI, 0.6 to 4.0). In the longitudinal analysis, antihypertensive use was associated with a lower rate of cognitive decline on the MMSE (-0.8 +/- 2 points in users vs -5.8 +/- 2.5 points in nonusers; p =.007) and on the CDT (-0.3 +/- 0.8 points in users vs -2.2 +/- 0.8 points in nonusers; p =.002), and with a lower risk for the development of cognitive impairment (odds ratio, 0.56; 95% CI, 0.38 to 0.83; p =.004). The trend was similar in patients with baseline AD (p =.02). Patients taking diuretics (p =.007), angiotensin-converting enzyme inhibitors (p =.016), and beta-blockers (p =.014) had a lower rate of cognitive decline, and patients taking angiotensin receptor blockers (p =.016) had improved cognitive scores.

CONCLUSIONS

Antihypertensive use, particularly diuretics, angiotensin-converting enzymes inhibitors, beta-blockers, and angiotensin receptor blockers, may be associated with a lower rate of cognitive decline in older adults, including those with AD. Until a randomized clinical trial confirms our results, findings of this observational study should be interpreted with caution.