Fibrin monomers evaluation during hospitalization for COVID-19 is a predictive marker of in-hospital mortality

Soluble Fibrin Monomer Complex and D-Dimer Concentrations Between Patients at Low and High Risk of Venous Thromboembolism Before Delivery According to RCOG Score Assessment: An Observational Study Among 100 Third-Trimester Vietnamese Pregnancies

Background/Objectives: Venous thromboembolism (VTE) is related to maternal mortality, especially after the coronavirus disease (COVID-19) pandemic. The Royal College of Obstetricians and Gynecologists (RCOG) guidelines' risk assessment score has been established to reduce thrombotic complications during pregnancy. Recently, it was found that the soluble fibrin monomer complex (SFMC) could be an alternative to D-dimer (DD), which has been used to assess the risk of VTE. This study aims to reveal the difference between FM and DD concentrations in low- and high-VTE-risk groups according to the RCOG's guidelines. Method: This observational study was conducted at the Department of High-Risk Pregnancy, Tu Du Hospital, Vietnam between August 2023 and April 2024. This study enrolled 100 pregnant women beyond 28 weeks of gestation at low risk (≤2 points) and high risk (≥3 points) of VTE assessment following the RCOG guidelines' score. Blood samples were collected for the SFMC and DD tests before delivery. Statistical tests were used to compare the difference in SFMC and DD concentrations between the two groups. A p-value < 0.05 is considered statistically significant. Results: We found no significant difference in DD and SFMC tests between low and high VTE risk (1.61 [1.30-2.30] vs. 1.51 [0.91-2.13]; 5.00 [1.36-9.78] vs. 3.74 [1.28-14.63], respectively; p > 0.05). The length of hospital stay in the high-risk group is longer than that of the low-risk group and involves postpartum infection. In addition, we found no significant correlation between the gestational age and SFMC or DD concentration. However, a moderate positive correlation between the two tests was found. Similarly, no significant correlation between the VTE score and SFMC or DD concentration was found in the present study. Conclusions: The soluble fibrin monomer complex and D-dimer tests are not significantly different between low-risk and high-risk groups determined through VTE evaluation before delivery according to the RCOG guidelines. The fibrin-linked tests need to be individualized and applied among pregnant women with higher scores of VTE risk based on maternal and pregnancy characteristics during antenatal care. Further studies with a larger number of participants are required to strengthen the findings.

The association between mortality due to COVID-19 and coagulative parameters: a systematic review and meta-analysis study

AIMS AND OBJECTIVES

This systematic review and meta-analysis study evaluated the association between mortality due to COVID-19 and coagulative factors.

METHODS

A systematic search was conducted on electronic databases including PubMed, Scopus, and the Web of Science from the beginning of the pandemic until October 2024 to identify relevant studies on COVID-19 patients and their laboratory findings related to coagulation markers and mortality outcome. Eligibility criteria were defined based on the PICO framework, and data extraction was performed by two authors independently using a standardized sheet. Statistical analysis was accomplished using the random effects model, and heterogeneity among studies was assessed using the I2 test. R and RStudio were used for statistical analysis and visualization.

RESULTS

Our systematic literature search yielded 6969 studies, with 48 studies meeting the inclusion criteria for our meta-analysis. The mean platelet count was significantly lower in deceased COVID-19 patients compared to survivors (20.58), while activated partial thromboplastin time (aPTT) and fibrinogen levels did not show significant differences. The pooled mean difference of D-Dimer, International Normalized Ratio (INR), and prothrombin time (PT) were significantly lower in survived patients (-2.45, -0.10, and -0.84, respectively). These findings suggest that platelet count, D-Dimer, INR, and PT may serve as potential indicators of mortality in COVID-19 patients.

CONCLUSION

The results of our systematic review and meta-analysis revealed a significant reduction in the pooled platelet count among deceased individuals when compared to survivors. However, no significant distinctions were observed in the pooled mean activated aPTT and fibrinogen levels between the deceased and survivor groups. On the other hand, there were noticeable variations in the pooled estimated mean of INR, PT, and D-Dimer levels, with significantly higher values in the deceased group compared to those who survived.

The role of vasculature and angiogenesis in respiratory diseases

In European countries, nearly 10% of all hospital admissions are related to respiratory diseases, mainly chronic life-threatening diseases such as COPD, pulmonary hypertension, IPF or lung cancer. The contribution of blood vessels and angiogenesis to lung regeneration, remodeling and disease progression has been increasingly appreciated. The vascular supply of the lung shows the peculiarity of dual perfusion of the pulmonary circulation (vasa publica), which maintains a functional blood-gas barrier, and the bronchial circulation (vasa privata), which reveals a profiled capacity for angiogenesis (namely intussusceptive and sprouting angiogenesis) and alveolar-vascular remodeling by the recruitment of endothelial precursor cells. The aim of this review is to outline the importance of vascular remodeling and angiogenesis in a variety of non-neoplastic and neoplastic acute and chronic respiratory diseases such as lung infection, COPD, lung fibrosis, pulmonary hypertension and lung cancer.

Vascular risk factors for COVID-19 ARDS: endothelium, contact-kinin system

SARS-CoV-2 binds to ACE2 receptors, expressed within the lungs. Risk factors for hospitalization include hypertension, diabetes, ischaemic heart disease and obesity-conditions linked by the presence of endothelial pathology. Viral infection in this setting causes increased conversion of circulating Factor XII to its active form (FXIIa). This is the first step in the contact-kinin pathway, leading to synchronous activation of the intrinsic coagulation cascade and the plasma Kallikrein-Kinin system, resulting in clotting and inflammatory lung disease. Temporal trends are evident from blood results of hospitalized patients. In the first week of symptoms the activated partial thromboplastin time (APTT) is prolonged. This can occur when clotting factors are consumed as part of the contact (intrinsic) pathway. Platelet counts initially fall, reflecting their consumption in coagulation. Lymphopenia occurs after approximately 1 week, reflecting the emergence of a lymphocytic pneumonitis [COVID-19 acute respiratory distress syndrome (ARDS)]. Intrinsic coagulation also induces the contact-kinin pathway of inflammation. A major product of this pathway, bradykinin causes oedema with ground glass opacities (GGO) on imaging in early COVID-19. Bradykinin also causes release of the pleiotrophic cytokine IL-6, which causes lymphocyte recruitment. Thromobosis and lymphocytic pneumonitis are hallmark features of COVID-19 ARDS. In this review we examine the literature with particular reference to the contact-kinin pathway. Measurements of platelets, lymphocytes and APTT should be undertaken in severe infections to stratify for risk of developing ARDS.