A Comprehensive Profiling of Hemostatic Activation and Thromboinflammatory Biomarkers and Cellular Indices in Predicting Outcomes in Venous Thromboembolism

Abstract

Despite advancements in diagnostic and therapeutic approaches, pulmonary embolism (PE) and deep vein thrombosis (DVT) in general remain challenging conditions due to their complex pathophysiological mechanisms. This thesis aims to comprehensively profile and evaluate the prognostic value of blood cellular indices and biomarkers in VTE with a specific focus on PE.

Materials and Method: This study was comprised of two independent groups of patients, namely the RIETE registry and LUMC PERT cohorts. Blood count data was used from 10,000 patients from the RIETE registry and provided the basis for cellular indices calculations. Blood samples from the PERT study, comprised of 500 patients with acute VTE, were analyzed for both cellular indices and biomarker profiling. The calculation of cellular indices included NLR, PLR, and SII. Plasma samples were tested for thrombin generation potential, and a comprehensive profiling of hemostatic activation and thromboinflammatory biomarkers using ELISA and biochip array. Statistical analysis included a descriptive test (median with IQR) and a comparative analysis (Chi square and Mann Whitney U tests). Prognostic analyses were performed using ROC curves and multivariate logistic regression analysis. Data was stratified on the basis of PE severity and 30-day mortality.

Results: Although the numbers of patients were different, both cohorts were demographically balanced. Among the VTE patients, NLR outperformed both PLR and SII for predicting mortality and major bleeding, while none of the cellular indices were predictive for VTE recurrence. Of all the cellular indices, NLR was found to be the best predictor for 30-day mortality in PE patients and demonstrated to have the highest predictive accuracy in low-risk PE patients. Furthermore, the incorporation of NLR in the clinical sPESI score enhanced the predictive power for identifying low-risk PE patients at increased risk of death. While thrombin generation potential was decreased in PE patients, thrombin generation markers such as D-dimer, F1+2, and TAT were increased. Combining the cellular indices with thrombin generation parameters amplified the predictive value for clinical outcomes in patients with PE. The relationships between thrombin generation potential, biomarkers, and cellular indices not only reinforced their relevance to the pathology of PE, but also emphasized the complexity of the disease including its severity. Additional hemostatic activation and thromboinflammatory biomarker profiling including endothelial dysregulation, platelet activation, coagulation activation, fibrinolysis process, and inflammatory markers including tissue factor were also performed in the 500 PE patients. Most of these biomarkers were significantly elevated consistent with PE severity and 30-day mortality. Taken together, these data suggest that combined use of cellular indices with biomarker data may improve the risk stratification to determine outcomes in these patients. Finally, a biochip array utilizing panel profiling for cytokines, chemokines, and growth factors was employed. The elevated levels, along with cellular indices data, correlated with PE severity and 30-day mortality outcome. These findings underscore the substantial predictive value of inflammatory markers and cellular indices in VTE/PE.

Conclusion: This dissertation focused on the prediction of the adverse clinical outcomes in patients with VTE using cellular indices and circulating biomarkers of hemostatic activation and inflammation. The findings demonstrated their relevance to the cellular modulation and biomarker changes associated with VTE, and PE in particular . Together the RIETE registry and the PERT program at Loyola, a robust investigation was able to be undertaken to demonstrate a unique approach using molecular and cellular parameters to improve the diagnosis of VTE. Not only risk stratification and clinical outcome predictions were enhanced, but application of the new information obtained in this thesis may also have implications to improve individualized therapy and develop novel therapeutic interventions for patients with VTE. This thesis provides a novel approach to refine the understanding of the pathophysiology of VTE and to improve patient health care.