No correlation between lower extremity deep vein thrombosis and pulmonary embolism proportions in trauma: a systematic literature review

In Situ Pulmonary Arterial Thrombosis-Literature Review and Clinical Significance of a Distinct Entity

Filling defects identified in the pulmonary arterial tree are commonly presumed to represent an embolic phenomenon originating from thrombi formed in remote veins, particularly lower-extremity deep venous thrombosis (DVT). However, accumulating evidence supports an underappreciated cause for pulmonary arterial thrombosis (PAT), namely, de novo thrombogenesis-where thrombosis arises within the pulmonary arteries in the absence of DVT. Although historically underrecognized, in situ PAT has become of heightened importance with the emergence of SARS-CoV-2 infection. In situ PAT is attributed to endothelial dysfunction, systemic inflammation, and acute lung injury, and has been described in a range of conditions including COVID-19, trauma, acute chest syndrome in sickle cell disease, pulmonary infections, and severe pulmonary arterial hypertension. The distinction between pulmonary embolus and in situ PAT may have important implications regarding management decisions and clinical outcomes. In this review, we summarize the pathophysiology, imaging appearances, and management of in situ PAT in various clinical situations. This understanding will promote optimal tailored treatment strategies for this increasingly recognized entity.

Incidence, risk factors and potential timing of occurrence of pulmonary embolism in fatal trauma: An autopsy based case-control study on 2705 victims

BACKGROUND

Pulmonary embolism (PE) following trauma is a potentially preventable but highly lethal complication. We sought to investigate the incidence, risk factors and potential timing of occurrence of post-traumatic PE in a large cohort of trauma fatalities.

METHODS

A case-control study on 9266 consecutive trauma fatalities (between 1996 and 2005) from a regional autopsy-based trauma registry. Injuries were classified according to the Abbreviated Injury Scale-1990 edition (AIS-90) and the Injury Severity Score (ISS) was calculated. Hospitalized victims were categorized according to the presence or absence of PE on autopsy. Univariate comparisons and multivariate logistic regression analysis for probabilities of association (odds ratios-OR) were performed.

RESULTS

Out of 2705 subjects who met the inclusion criteria, 116 had autopsy findings of PE and constituted the PE group (incidence of 4,3%), while the remaining victims formed the control group. The survival time of the PE group ranged from 0.66 to 104.73 days. Victims in the PE group were older (median age 69.5 vs 59), had lower ISS values (median 16 vs 26) and longer post-injury survival times (median 13.6 vs 5.7 days). Positively associated risk factors were AIS2-5 pelvic ring injuries (OR:2.23) and secondary deaths following an uneventful hospital discharge (OR:3.97), while AIS2-5 head (OR:0.33) and abdominal injuries (OR:0.23) showed a reverse association.

CONCLUSIONS

Trauma fatalities with autopsy findings of PE were associated with less severe trauma indicating that PE was likely detrimental to the fatal outcome. Both the early and delayed occurrence of PE was reaffirmed. Prophylactic measures should be initiated promptly and extended post discharge for high risk patients to prevent secondary deaths.

Qualitative analysis of randomized controlled trials informing recommendations for venous thromboembolism prophylaxis after distal lower extremity injuries

Purpose:

The purpose of this study is to assess the quality of evidence to stratify recommendations for chemoprophylaxis following distal lower extremity trauma.

Methods:

Literature review identified primary studies investigating venous thromboembolism (VTE) chemoprophylaxis following traumatic injury distal to the knee. Inclusion criteria were randomized controlled trials in adult patients treated with and without operative intervention. Each primary study was assessed by the Consolidated Standards of Reporting Trials 2010 checklist and Modified Coleman methodology score.

Results:

Literature review resulted in 462 studies, of which 9 met inclusion and exclusion criteria. All studies included low molecular weight heparin as a treatment group with 2 (22%) also including a treatment group with a direct factor Xa inhibitor. Five studies (56%) used placebo as a control group. The mean Modified Coleman Methodology score was 63% (range 51%–72%), a categorical rating of Fair. The mean Consolidated Standards of Reporting Trials score was 78% (range 56%–97%). Most studies (89%) screened all asymptomatic subjects for deep venous thrombosis. Statistical significance in VTE incidence among prophylactic treatment groups was not achieved in 78%.

Conclusions:

Development of consensus for VTE prophylaxis recommendations following traumatic injury distal to the knee is complicated by heterogenous study populations, low incidence of VTE in study populations, and inconsistent definitions of clinically important VTE. Low molecular weight heparin is not consistently superior for preventing VTE. Chemoprophylaxis should be considered on an individual basis in the presence of additional risk factors, although an externally validated, evidence-based risk assessment tool does not currently exist.

Level of Evidence: IV, therapeutic

Varicose Veins and Risk of Venous Thromboembolic Diseases: A Two-Sample-Based Mendelian Randomization Study

Background

Varicose veins are found to be associated with increased risk of venous thromboembolism (VTE) in many observational studies, but whether varicose veins are causally associated with VTE remains unclear. Therefore, we used a series of Mendelian randomization (MR) methods to investigate that association.

Methods

23 independent single-nucleotide polymorphisms (SNPs) for varicose veins were obtained from the Pan UK Biobank analysis. The outcomes datasets for deep vein thrombosis (DVT), pulmonary embolism (PE) and venous thromboembolism (VTE) were obtained from the FinnGen study. Before analysis, body mass index (BMI) and height were included as confounders in our MR model. Basic MR [inverse-variance weighted (IVW), weight-median, penalized weighted-median and MR-Egger methods] and MR-PRESSO were performed against each outcome using the whole SNPs and SNPs after excluding those associated with confounders. If causal associations were suggested for any outcome, a basic MR validation analysis, a multivariable MR analysis with BMI and height, a Causal Analysis Using Summary Effect estimates (CAUSE), and a two-step MR analysis with BMI and height, would follow.

Results

Using 21 qualified SNPs, the IVW method (OR: 1.173, 95% CI: 1.070-1.286, p < 0.001, FDR = 0.002), the weighted median method (OR: 1.255, 95% CI: 1.106-1.423, p < 0.001, FDR = 0.001), the penalized weighted median method (OR: 1.299, 95% CI: 1.128-1.495, p < 0.001, FDR = 0.001) and the MR-PRESSO (OR: 1.165, 95% CI: 1.067-1.273, p = 0.003, FDR = 0.009) suggested potential causal effect of varicose veins on DVT, but no cause effect was found for PE and VTE. Excluding SNPs associated with confounders yielded similar results. The causal association with DVT was validated using a self-reported DVT cohort (IVW, OR: 1.107, 95% CI: 1.041-1.178, p = 0.001). The causal association maintained after adjustment for height (OR = 1.105, 95% CI: 1.028-1.188, p = 0.007), BMI (OR = 1.148, 95% CI: 1.059-1.244, p < 0.001) and them both (OR = 1.104, 95% CI: 1.035-1.177, p = 0.003). The causal association also survived the strict CAUSE (p = 0.018). Finally, in two-step MR, height and BMI were found to have causal effects on both varicose veins and DVT.

Conclusion

Genetically predicted varicose veins may have a causal effect on DVT and may be one of the mediators of obesity and taller height that predispose to DVT.

Early Detection of Deep Venous Thrombosis in Trauma Patients

Background

This study was performed to determine whether trauma patients are at an increased risk of developing deep venous thrombosis (DVT) within the first 48 hours of hospitalization.

Materials and methods

A retrospective review was performed using a prospectively maintained database of patients admitted to a trauma center during a five-year time period. Patients hospitalized for greater than 48 hours who received a screening venous duplex for DVT were included in the study.

Results

There were 1067 venous duplex scans obtained, 689 (64.5%) within the first 48 hours of admission (early DVT group), 378 (35.4%) after the first 48 hours (late DVT group). Only 142 (13.2%) patients had a positive duplex scan for DVT, 55 (early group), 87 (late group). Comorbid conditions of congestive heart failure (P = 0.02), pelvic fractures (P = 0.04), and a lower initial systolic blood pressure on presentation (p = 0.04) were associated with early DVT. Head trauma (P < 0.01), mechanical ventilation (P < 0.001), and transfusion of blood products (P < 0.001), were predictors of DVT in the late group.

Conclusions

Trauma patients are at an increased risk of developing venous thrombosis early in the hospital course due to comorbidities associated with trauma. Whereas, venous thrombosis in trauma patients diagnosed after the first 48 hours of hospitalization appears to be associated with prolonged patient immobility.