Fatal pulmonary thromboembolism. A retrospective autopsy study: searching for genetic thrombophilias (Factor V Leiden (G1691A) and FII (G20210A) gene variants) and dating the thrombus

State-of-Art in the Age Determination of Venous Thromboembolism: A Systematic Review

Venous thromboembolism (VTE), consisting of deep vein thrombosis (DVT) and pulmonary embolism (PE), requires a forensic age determination to ascertain their causal relationship with recent events, such as trauma or medical treatment. The main objective of this systematic review is to identify the current state-of-the-art immunohistochemical methods for age determination of fatal VTE. A literature search was performed through different databases, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Within the study, we have selected only cases represented by deceased patients for DVT and/or PTE in which thromboembolic material was collected during an autoptic examination and then subjected to a histological and an immunohistochemical investigation. Studies based on animal models were not included. We assessed bias risk. A database-based search produced a total of 19 articles. After excluding duplicate items from the selection, 14 articles were reviewed. Ten articles were excluded because they did not meet the inclusion criteria. The results have pointed out 4 studies that were included in the present analysis for a total of 157 samples of DVT and 171 PTE samples. These were analyzed using traditional histological and immunohistochemical techniques. The results must be interpreted with a critical eye because of their heterogeneity in terms of time, geography, and study design. The present review highlights the importance of associating specific immunohistochemical markers with a histological analysis for the timing of DVT/PTE fatal events. Further future experiences will hopefully endorse actual knowledge on the subject to increase the accuracy in the assessment of thrombus-embolus age.

Application of Immunohistochemistry and Special Staining Technique in Forensic Traumatic Pathology Identification

In forensic traumatic pathology practice, immunohistochemistry and special staining technique play an important role in wound age estimation and complications of traumatic complication identification. They even play an important role in the identification of special cases, such as snakebites and insulin killings. This article reviews the application and value of immunohistochemistry and special staining techniques in forensic traumatic pathology based on the cases of forensic practice reported in literature.

Resolution of Deep Venous Thrombosis: Proposed Immune Paradigms

Venous thromboembolism (VTE) is a pathology encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with high morbidity and mortality. Because patients often present after a thrombus has already formed, the mechanisms that drive DVT resolution are being investigated in search of treatment. Herein, we review the current literature, including the molecular mechanisms of fibrinolysis and collagenolysis, as well as the critical cellular roles of macrophages, neutrophils, and endothelial cells. We propose two general models for the operation of the immune system in the context of venous thrombosis. In early thrombus resolution, neutrophil influx stabilizes the tissue through NETosis. Meanwhile, macrophages and intact neutrophils recognize the extracellular DNA by the TLR9 receptor and induce fibrosis, a complimentary stabilization method. At later stages of resolution, pro-inflammatory macrophages police the thrombus for pathogens, a role supported by both T-cells and mast cells. Once they verify sterility, these macrophages transform into their pro-resolving phenotype. Endothelial cells both coat the stabilized thrombus, a necessary early step, and can undergo an endothelial-mesenchymal transition, which impedes DVT resolution. Several of these interactions hold promise for future therapy.

The dating of thrombus organization in cases of pulmonary embolism: an autopsy study

Background

Pulmonary embolism (PE) is associated to high mortality rate worldwide. However, the diagnosis of PE often results inaccurate. Many cases of PE are incorrectly diagnosed or missed and they are often associated to sudden unexpected death (SUD). In forensic practice, it is important to establish the time of thrombus formation in order to determine the precise moment of death. The autopsy remains the gold standard method for the identification of death cause allowing the determination of discrepancies between clinical and autopsy diagnoses. The aim of our study was to verify the morphological and histological criteria of fatal cases of PE and evaluate the dating of thrombus formation considering 5 ranges of time.

Methods

Pulmonary vessels sections were collected from January 2010 to December 2017. Sections of thrombus sampling were stained with hematoxylin and eosin. The content of infiltrated cells, fibroblasts and collagen fibers were scored using a semi-quantitative three-point scale of range values.

Results

The 30 autopsies included 19 males (63.3%) and 11 females (36.7%) with an average age of 64.5 ± 12.3 years. The time intervals were as follows: early (≤1 h), recent (> 1 h to 24 h), recent-medium (> 24 h to 48 h), medium (> 48 h to 72 h) and old (> 72 h). In the first hour, we histologically observed the presence of platelet aggregation by immunofluorescence method for factor VIII and fibrinogen. The presence of lymphocytes has been identified from recent thrombus (> 1 h to 24 h) and the fibroblast cells were peripherally located in vascular tissue between 48 and 72 h, whereas they resulted central and copious after 72 h.

Conclusions

After a macroscopic observation and a good sampling traditional histology, it is important to identify the time of thrombus formation. We identified histologically a range of time in the physiopathology of the thrombus (early, recent, recent-medium, medium, old), allowing to determine the dating of thrombus formation and the exact time of death.

Clinical trial number

NCT03887819.

Trial registration

The trial registry is Cliniclatrials.gov, with the unique identifying number NCT03887819. The date of registration was 03/23/2019 and it was “Retrospectively registered”.

Investigation on genetic thrombophilic factors in FFPE autopsy tissue from subjects who died from pulmonary embolism

Venous thromboembolism (VTE) is a multifactorial disease determined by a combination of inherited and acquired factors. Inherited factors include mutations in the genes coding for coagulation factors, some of which seem to exert a differential influence on the risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE). In post-mortem studies of subjects who have died from pulmonary embolism (PE), the analysis of the factors that may have augmented the VTE risk is often limited to acquired factors. This is due to the complexity-and sometimes the unfeasibility-of analyzing genetic factors and to insufficient knowledge of their individual roles in PE development. The present study used formalin-fixed paraffin-embedded (FFPE) tissue to investigate a panel of 12 polymorphisms-the largest ever studied-that affect the VTE risk. Tissue samples came from post-mortem examinations performed by the specialists of the Section of Legal Medicine of the Department of Pathology of Marche's Polytechnic University, and by the specialists of Health Care District Hospital of Imola, on 44 subjects who died from PE in the period 1997-2014. All individuals were found to have at least one mutation affecting the VTE risk. The present study demonstrates that genetic analysis can be performed post-mortem and the results are useful for forensic investigations, especially from MTHFR C677T and PAI-1 4G/5G polymorphisms. Broader studies using the techniques described herein are needed to determine the relative influence of the individual polymorphisms and their interaction in PE deaths.

Multi-phase postmortem CT angiography (MPMCTA): a new axillary approach suitable in fatal thromboembolism

Postmor tem computed tomography is widely used in the forensic pathology setting as supplementing medico-legal investigations and being capable of providing significant data that affect final conclusions and adding new quality to recording postmortem observations. The integration with angiographic methods [postmortem computed tomography angiography and multiphase postmortem CT angiography (MPMCTA)] allows the examination of the cardiovascular system and it is increasingly being utilised in the field of forensic pathology. However, using the standardised procedure that establishes the femoral vessels on one side of the corpse as an access point to the vascular system, visualisation of the vascular tree below the cannula insertion site is excluded. Consequently, visualisation of the vascular anatomy and morphology of the lower limbs is impossible and lesions such as thrombosis of the superficial and deep venous system may remain elusive. Bearing in mind the high incidence of pulmonary thromboembolism in forensic case studies and the difficulties in postmortem diagnosis, we propose a new axillary approach for MPMCTA that allows the full detection of the vascular system of the lower limbs.