Neutrophil activation and circulating neutrophil extracellular traps are increased in venous thromboembolism patients for at least one year after the clinical event.

Neutrophil activation and neutrophil extracellular traps (NETs) have been associated with the pathogenesis of venous thromboembolism (VTE). Considering VTE-associated chronic sequelae, which suggest that some pathological mechanisms remain after the acute episode, we investigated whether neutrophil activation is increased in patients with a prior VTE at least one year before this investigation. Thirty-seven patients with prior VTE and 37 individuals with no history of VTE were included. Neutrophil activity was evaluated by the expression of the adhesive molecule activation-specific epitopes LFA-1 (CD11a) and MAC-1 (CD11b), chemotaxis, reactive oxygen species (ROS) and by MPO-DNA complexes as markers of NETs. The adhesive molecules sICAM-1 and sVCAM-1, involved in the cross talk between neutrophil and endothelial cells, were also evaluated. Patient neutrophils presented increased CD11a expression before and after TNF-α stimulus, whereas increased CD11b expression was observed only after TNF-α stimulus, as compared to controls. Neutrophil chemotaxis on both, basal state and after IL-8 stimulus, on circulating levels of sICAM-1 and sVCAM-1, and on MPO-DNA complexes were also increased in VTE patients. ROS release was similar between patients and controls. This is, to our knowledge, the first study to investigate neutrophil inflammatory activity in VTE patients a long period after an acute event (approximately 2 years). The results showed altered neutrophil activation patterns in these patients. While activated neutrophils can cause endothelial activation and injury, the activated endothelium can induce the release of NETs with consequent endothelial cytotoxicity, creating a vicious cycle of activation between neutrophils and endothelium that can lead to thrombosis. VTE patients (approximately 2 years after the clinical event) present an altered neutrophil activation state evidenced by increased activity of the LFA-1 and Mac-1 adhesive molecules, as well as increased chemotaxis and circulating levels of NETs remnants. Circulating levels of ICAM-1 and VCAM-1, which are endothelial adhesive molecules, are also increased in VTE patients, suggesting not only an exacerbated endothelial activation and dysfunction, but also an interaction of the neutrophil adhesive molecules with their endothelial ligands, favoring the migration process of neutrophil.

Residual Vein Thrombosis Echogenicity Is Associated to the Risk of DVT Recurrence: A Cohort Study.

Although deep vein thrombosis (DVT) recurrence is a common late complication of the disease, there are few predictive markers to risk-stratify patients long-term after the thrombotic event. The accuracy of residual vein thrombosis (RVT) in this context is controversial, possibly due to a lack of a standardized methodology. The objective of the study was to evaluate the accuracy of RVT echogenicity as a predictive marker of late DVT recurrence. To evaluate the accuracy of RVT echogenicity as a predictive marker of late DVT recurrence. This prospective study included patients with history of DVT in the past 33 months. Ultrasound examination was performed to detect the presence of RVT, and its echogenicity was determined by calculating the grayscale median (GSM) of the images. Blood samplings were taken for plasma D-dimer levels. Patients were followed-up for 28 months and the primary end point was DVT recurrence. Deep vein thrombosis recurrence was confirmed or excluded by ultrasound during the follow-up. Fifty-six patients were included, of which 10 presented DVT recurrence during the follow-up. D-dimer levels above 630 ng/mL conferred higher risk for recurrence with a negative predictive value of 94%. The absence of RVT was a protective marker for recurrence with a negative predictive value of 100%. Also, the presence of hypoechoic RVT, determined by GSM values below 24, positively predicted 75% of DVT recurrences. Our results suggest that the persistence of RVT and, particularly, the presence of hypoechoic thrombi (GSM < 24) are predictive markers of the risk of DVT recurrence. Residual vein thrombosis echogenicity, by GSM analysis, could represent a new strategy for the evaluation of recurrence risk in patients with DVT.

Severe postthrombotic syndrome is associated with characteristic sonographic pattern of the residual thrombosis.

Postthrombotic syndrome (PTS) may affect 50% of patients with deep venous thrombosis, 5-10% of them may present severe manifestations. The causes for PTS development and severity have not been well established. This study evaluated whether PTS may be associated with the presence, and echogenicity, of the residual vein thrombosis (RVT). We included patients with a history of deep venous thrombosis in the past 58 months. These patients were further evaluated for PTS diagnosis, clinical comorbidities, plasma levels of D-dimer, serum levels of C-reactive protein and for the presence of RVT. Particularly, RVT was detected by ultrasound examination and the residual thrombi echogenicity was determined by grayscale median (GSM). Fifty-six patients were included, of which 41 presented PTS. Mild PTS was detected in 23 patients, moderate PTS in 11 and severe PTS in seven patients. Patients with severe PTS showed higher body mass index, higher abdominal circumference and higher C-reactive protein levels when compared with the other patients (P = 0.007, P = 0.002, P = 0.02, respectively). The ultrasound-generated GSM was significantly lower in patients with severe PTS compared with patients with mild-moderate PTS or no PTS (median = 24, 35 and 41, respectively; P = 0.04). A GSM value less than 25, which was consistent with a hypoechoic RVT, was the best cut-off value to discriminate patients with severe PTS from those with mild or moderate PTS and those without PTS. RVT is a common finding among patients with PTS and the echogenicity of the RVT may impact the severity of PTS.

Increased adhesive properties of neutrophils and inflammatory markers in venous thromboembolism patients with residual vein occlusion and high D-dimer levels.

BACKGROUND: Venous thromboembolism (VTE) develops via a multicellular process on the endothelial surface. Although widely recognized, the relationship between inflammation and thrombosis, this relationship has been mostly explored in clinical studies by measuring circulating levels of inflammatory cytokines. However, the role of inflammatory cells, such as neutrophils, in the pathogenesis of VTE is not clear in humans. AIMS: To evaluate the adhesive properties of neutrophils, erythrocytes and platelets in VTE patients and to correlate findings with inflammatory and hypercoagulability marker levels. METHODS: Study group consisted of twenty-nine VTE patients and controls matched according to age, gender and ethnic background. Adhesive properties of neutrophils, erythrocytes and platelets were determined using a static adhesion assay. Neutrophil adhesion molecules expressions were evaluated by flow cytometry. Inflammatory and hypercoagulability marker levels were evaluated by standard methods. Residual vein occlusion (RVO) was evaluated by Doppler ultrasound. RESULTS: No significant difference could be observed in platelet and erythrocyte adhesion between VTE patients and controls. Interestingly, VTE patients with high levels of D-dimer and RVO, demonstrated a significant increase in neutrophil adhesion, compared to controls and remaining patients. Inflammatory markers (IL-6, IL-8, TNF-α) were also significantly elevated in this subgroup, compared to other VTE patients. Adhesive properties of neutrophils correlated with IL-6 and D-dimer levels. Neutrophils adhesion molecules (CD11a, CD11b and CD18) were not altered in any of the groups. CONCLUSION: These findings not only support the hypothesis of an association between inflammation and hypercoagulability, but more importantly, highlight the role of neutrophils in this process.