Age, sex and racial differences in fibrin formation and fibrinolysis within the healthy population

Overall haemostatic potential assay for prediction of outcomes in venous and arterial thrombosis and thrombo-inflammatory diseases

Thromboembolic diseases including arterial and venous thrombosis are common causes of morbidity and mortality globally. Thrombosis frequently recurs and can also complicate many inflammatory conditions through the process of 'thrombo-inflammation,' as evidenced during the COVID-19 pandemic. Current candidate biomarkers for thrombosis prediction, such as D-dimer, have poor predictive efficacy. This limits our capacity to tailor anticoagulation duration individually and may expose lower risk individuals to undue bleeding risk. Global coagulation assays, such as the Overall Haemostatic Potential (OHP) assay, that investigate fibrin generation and fibrinolysis, may provide a more accurate and functional assessment of hypercoagulability. We present a review of fibrin's critical role as a central modulator of thrombotic risk. The results of our studies demonstrating the OHP assay as a predictive biomarker in venous thromboembolism, chronic renal disease, diabetes mellitus, post-thrombotic syndrome, and COVID-19 are discussed. As a comprehensive and global measurement of fibrin generation and fibrinolytic capacity, the OHP assay may be a valuable addition to future multi-modal predictive tools in thrombosis.

Thromboelastography in acute immunologic reactions: a prospective pilot study

Background

Biomarkers of fibrinolysis are elevated during acute immunologic reactions (allergic reactions and angioedema), although it is unclear whether fibrinolysis is associated with disease severity.

Objectives

We investigated a possible association between maximum lysis (ML) measured by thromboelastography and the severity of acute immunologic reactions.

Methods

We recruited patients with acute immunologic reactions at a high-volume emergency department. Clinical disease severity at presentation and at the end of the emergency department stay was assessed using a 5-grade scale, ranging from local symptoms to cardiac arrest. We determined ML on admission by thromboelastography (ROTEM's extrinsic [EXTEM], and aprotinin [APTEM] tests), expressed as ML%. Hyperfibrinolysis was defined as an ML of >15% in EXTEM, which was reversed by adding aprotinin (APTEM). We used exact logistic regression to investigate an association between ML% and disease severity (grades 1 and 2 [mild] vs 3-5 [severe]) and between hyperfibrinolysis and disease severity.

Results

We included 31 patients (71% female; median age, 52 [IQR, 35-58] years; 10 [32%] with a severe reaction). ML% was higher in patients with severe symptoms (21 [IQR, 12-100] vs 10 [IQR, 4-17]). Logistic regression found a significant association between ML% and symptom severity (odds ratio, 1.07; 95% CI, 1.01-1.21; P = .003). Hyperfibrinolysis was detected in 6 patients and found to be associated with severe symptoms (odds ratio, 17.59; 95% CI, 1.52-991.09; P = .02). D-dimer, tryptase, and immunoglobulin E concentrations increased with the severity of immunologic reactions.

Conclusion

ML, quantified by thromboelastography, is associated with the severity of acute immunologic reactions.

Risk factors for arterial catheter failure and complications during critical care hospitalisation: a secondary analysis of a multisite, randomised trial

OBJECTIVES

Arterial catheters (ACs) are critical for haemodynamic monitoring and blood sampling but are prone to complications. We investigated the incidence and risk factors of AC failure.

METHODS

Secondary analysis of a multi-centre randomised controlled trial (ACTRN 12610000505000). Analysis included a subset of adult intensive care unit patients with an AC. The primary outcome was all-cause device failure. Secondary outcomes were catheter associated bloodstream infection (CABSI), suspected CABSI, occlusion, thrombosis, accidental removal, pain, and line fracture. Risk factors associated with AC failure were investigated using Cox proportional hazards and competing-risk models.

RESULTS

Of 664 patients, 173 (26%) experienced AC failure (incidence rate [IR] 37/1000 catheter days). Suspected CABSI was the most common failure type (11%; IR 15.3/1000 catheter days), followed by occlusion (8%; IR 11.9/1,000 catheter days), and accidental removal (4%; IR 5.5/1000 catheter days). CABSI occurred in 16 (2%) patients. All-cause failure and occlusion were reduced with ultrasound-assisted insertion (failure: adjusted hazard ratio [HR] 0.43, 95% CI 0.25, 0.76; occlusion: sub-HR 0.11, 95% CI 0.03, 0.43). Increased age was associated with less AC failure (60-74 years HR 0.63, 95% CI 0.44 to 0.89; 75 + years HR 0.36, 95% CI 0.20, 0.64; referent 15-59 years). Females experienced more occlusion (adjusted sub-HR 2.53, 95% CI 1.49, 4.29), while patients with diabetes had less (SHR 0.15, 95% CI 0.04, 0.63). Suspected CABSI was associated with an abnormal insertion site appearance (SHR 2.71, 95% CI 1.48, 4.99).

CONCLUSIONS

AC failure is common with ultrasound-guided insertion associated with lower failure rates. Trial registration Australian New Zealand Clinical Trial Registry (ACTRN 12610000505000); date registered: 18 June 2010.

Traumatic coagulopathy in the older patient: analysis of coagulation profiles from the Activation of Coagulation and Inflammation in Trauma-2 (ACIT-2) observational, multicenter study

BACKGROUND

Most studies describing traumatic coagulopathy have used data from patient cohorts with an average age of between 35 and 45 years. The last 10 years has seen a steep increase in the number of patients admitted with significant injury and bleeding who are older than the age of 65 years. Many coagulation protein levels alter significantly with normal aging, and it is possible that traumatic coagulopathy has a different signature with age.

OBJECTIVES

The aim of this study was to report the coagulation profiles, including standard and extended laboratory, as well as viscoelastic hemostatic assays, stratified according to age to explore age-related differences in hemostatic capability.

METHODS

In total, 1576 patients were analyzed from 6 European level 1 trauma centers.

RESULTS

As age increased, there was evidence of higher fibrinogen, greater thrombin generation, greater clotting factor consumption, and greater activation of fibrinolysis. Despite this, shock and severe injury led to the same pattern of changes within age groups: lower procoagulant factors (including fibrinogen), increased fibrinolysis, and higher levels of activated protein C. Thromboelastography and rotational thromboelastometry tests detected traumatic coagulopathy with prolongation of R/clotting time and reductions in clot amplitudes in each age cohort. Advancing age strongly correlated with higher fibrinogen levels and greater fibrinolysis.

CONCLUSION

Age-related coagulation changes are evident in injured patients. Broadly, similar patterns of coagulation abnormalities are seen across age groups following severe injury/shock, but thresholds for single clotting factors differ. Age-related differences may need to be considered when clinical treatments (eg, transfusion therapy) are indicated.

Impaired Fibrinolytic Potential Predicts Oxygen Requirement in COVID-19

Abnormal coagulation and fibrinolysis contributes to the respiratory distress syndrome in COVID-19. We aimed to explore the association of impaired fibrinolytic potential with disease severity and oxygen requirement in hospitalized patients. Adults admitted to hospital with confirmed COVID-19 infection between 1–31 January 2022 were included, corresponding to the first Omicron outbreak in Melbourne, Victoria. The first citrated plasma sample requested within 24 h of the patient’s presentation was obtained and analyzed by the overall hemostatic potential (OHP) assay, a spectrophotometric assay in which fibrin formation (triggered by small amounts of thrombin (OCP)) and fibrinolysis (by the addition of thrombin and tissue plasminogen activator (OHP and OFP%)) were simultaneously measured. There were 266 patients (median 72 years, 52.9% male), of which 49.6% did not require oxygen therapy. COVID-19 severity and requirement for oxygen was significantly associated with higher OCP, OHP, and lower OFP%. Vaccinated individuals compared with non-vaccinated individuals had significantly lower OHP (16.5 vs. 23.1, p = 0.015) and higher OFP (72.0% vs. 65.1%, p = 0.005), as well as significantly lower AST, ferritin, LDH, CRP, and D-dimer. A multivariate model containing OHP was constructed with the outcome of oxygen requirement, with c-statistic of 0.85 (95%CI 0.81–0.90). In this pilot study, we show a significant correlation between OHP results and requirement for oxygen supplementation in hospitalized patients during a period dominated by the Omicron variant. The results were incorporated into a multivariate model that predicted for oxygen requirement, with high discriminative ability.