Trace metals and the hemostatic system.

In this narrative review we report the main relationships between trace metals and the hemostatic system since this aspect has seldom attracted the attention of the scientific community. A basic aspect to be considered is the importance of maintaining the fine control of all trace metals' levels since they have an important impact on the pathophysiology of the hemostatic system. It is worth noting that poor diet habits are responsible for most trace metal deficiencies, while pollution is responsible for dangerous exposure to them with a consequent negative impact on the general population. This appears of paramount importance in planning the implementation of food and nutrient support to ameliorate the hidden hunger and the quality of life of people especially in developing countries and limiting poisons both in the air and food. As it often happens, when damage to certain mechanisms takes a very long time to appear, no attention is paid to the importance of a systematic prevention to avoid late negative outcomes.

Over-anticoagulation by vitamin K antagonists and gender differences.

BACKGROUND: Several studies have shown that in patients treated with vitamin K antagonists (VKAs) time spent in therapeutic range (TTR) is lower in females than in males. This retrospective study has evaluated a possible association among over-anticoagulation and gender, type and indications to VKAs, TTR and bleeding. Moreover, the decrease of the INR level, after VKAs withdrawal, was considered. METHODS: From December 2020 to January 2004, 1230 patients with venous thromboembolism or atrial fibrillation were enrolled. Age, gender, type of VKAs, clinical indications, INR values and bleeding events were recorded. TTR was calculated considering the entire period of treatment. RESULTS: A total of 1616 and 1759 over-anticoagulation episodes were found in males and females, respectively. The median INR value was 4.5 (4.0-19.04). Thirty-two percent of the patients did not have an overdose throughout the observation period. The median number of over-anticoagulation per year was significantly higher in females (0.39-year) than in males (0.28-year). After 24 h of VKAs withdrawal, INRs were similar in both genders. Logistic regression analysis showed that the episodes of over-anticoagulation per year were associated with females, atrial fibrillation, warfarin therapy, follow-up length longer than 4 years, and TTR <73%, but were not associated to bleeding episodes. CONCLUSION: The higher number of over-anticoagulation can explain the lower TTR in females. An excess of anticoagulation is not associated with bleeding events. The recovery of INR performs better when acenocoumarol is used, therefore, in patients who present several episodes of over-anticoagulation, acenocumarolo could replace warfarin.

Ultrastructural findings of lung injury due to Vaccine-induced Immune Thrombotic Thrombo- cytopenia (VITT) following COVID-19 vaccination: a scanning electron microscopic study.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare new syndrome occurring after the ChAdOx1 nCoV-19 vaccine immunization. Patients with VITT are characterized by a variable clinical presentation, likewise also the outcome of these patients is very variable. Here we report the lung ultrastructural findings in the course of VITT of a 58-year-old male patient. Alveoli were mainly dilated, irregular in shape, and occupied by a reticular network of fibrin, while interalveolar septa appeared thickened. The proliferation of small capillaries gave rise to plexiform structures and pulmonary capillary hemangiomatosis-like features. Near the alveoli occupied by a dense fibrin network, the medium-sized arteries showed a modified wall and an intraluminal thrombus. This scenario looks quite similar to that found during COVID-19, where the lungs suffer from the attack of the antigen-antibodies complexes and the virus respectively. In both diseases, the final outcome is a severe inflammation, activation of the haemostatic system and fibrinolysis.

Acute embolisms in multiple arterial districts following Ad26.COV2-S vaccine.

A case of multiple arterial thrombosis/embolisms in a 74-year-old Caucasian man with no other cardiovascular risk factors who received Ad26.COV2-S vaccine 16 days before is reported. The unusual presentation required a longer diagnostic workup. The clinical manifestations and the therapy-specific response suggest an unusual presentation of Vaccine-induced immune thrombotic thrombocytopenia (VITT).

Fetal programming of atherosclerosis: may the barker hypothesis explain the susceptibility of a subset of patients to develop stroke or cardiac infarct?

The risk stratification of young adults between subjects who will develop a mild form of atherosclerosis and subjects who will undergo a severe disease remains inaccurate. In the eighties of the previous century, David JP Barker has demonstrated the relationship between fetal conditions and occurrence of pathologies in adulthood. In this paper, the multiple evidence that might explain the increased susceptibility to severe forms of atherosclerosis, including stroke and cardiac infarct, in subjects who underwent intrauterine growth restriction (IUGR) will be analyzed. Specifically, we will review those inter-connected data indicating an association between a low weight at birth and an adult phenotype which might favor a severe outcome of atherosclerosis. Young and adult subjects born too small (IUGR) or too early (pre-terms) might represent a subgroup of "at risk subjects", more susceptible toward severe forms of atherosclerosis. Given that low birth weight (LBW) may be considered a surrogate of IUGR, this phenotypic feature could be considered among those indispensable clinical data collected in every patient presenting with atherosclerosis, irrespectively of age. According to the hypothesis that structural arterial changes might represent the link between LBW and susceptibility to atherosclerosis later in life, we suggest that the prevention of atherosclerosis should begin at birth. Regenerative and physiological substances such as thymosin Beta-4 could be challenged for a new "arterial regenerative medicine" in the perinatal period. The goal of this new approach should be the reinforcement of the structure of the arterial wall, allowing LBW newborns to avoid the most severe complications of atherosclerosis later in life: a dream that our research could contribute to bringing to life.

Aortic vulnerability to COVID-19: is the microvasculature of vasa vasorum a key factor? A case report and a review of the literature.

Arterial thromboembolic complications reported in patients with COVID-19 infection suggested that SARS-CoV-2 can trigger atherosclerotic plaque vulnerability. While endothelial cells in healthy subjects protect against thrombus formation, after injury they show prothrombotic activity. In addition, it has been hypothesized that "cytokine storm" might stimulate the production of neo-platelets triggering an abnormal "immunothrombosis" responsible for the hypercoagulable state induced in COVID-19 patients. The aim of this study is to report a case of severe COVID-19 infection characterized by the occurrence of microthrombosis in the vasa vasorum of the aorta. A 67-year-old male patient, in good health status and without comorbidities, who underwent a severe COVID-19 infection with fatal outcome, showed scattered aortic atherosclerotic plaques, characterized by multiple occlusive micro-thromboses in the vasa vasorum, spread out lymphocytic infiltrates and foci of endotheliitis and endothelial detachment. This case report confirms the previously described thrombotic involvement of vasa vasorum in COVID-19. The occurrence of the synchronous damage involving both the lumen surface (endothelial dysfunction, endotheliitis and endothelial detachment) and the adventitia (inflammation and occlusive thrombosis of vasa vasorum) could be the key points related to the fatal outcome of the SARS-CoV-2 patients. In our opinion, vasa vasorum thrombosis may thus initiate an atherogenic process that could be characterized by a much more rapid development.

Thrombotic sinusoiditis and local diffuse intrasinusoidal coagulation in the liver of subjects affected by COVID-19: the evidence from histology and scanning electron microscopy.

OBJECTIVE: Liver injury has been reported in patients with COVID-19. This condition is characterized by severe outcome and could be related with the ability of SARS-CoV-2 to activate cytotoxic T cells. The purpose of this study is to show the histological and scanning electron microscopy features of liver involvement in COVID-19 to characterize the liver changes caused by the activation of multiple molecular pathways following this infection. PATIENTS AND METHODS: Liver biopsies from 4 patients (3 post-mortems and 1 in vivo) with COVID-19 were analyzed with histology and by scanning electron microscopy. RESULTS: The liver changes showed significant heterogeneity. The first case showed ground glass hepatocytes and scattered fibrin aggregates in the sinusoidal lumen. The second evidenced intra-sinusoidal thrombi. The third was characterized by sinusoidal dilatation, atrophy of hepatocytes, Disse's spaces dilatation and intra-sinusoidal aggregates of fibrin and red blood cells. The fourth case exhibited diffuse fibrin aggregates in the dilated Disse spaces and microthrombi in the sinusoidal lumen. CONCLUSIONS: In COVID-19-related liver injury, a large spectrum of pathological changes was observed. The most peculiar features were very mild inflammation, intra-sinusoidal changes, including sinusoidal dilatation, thrombotic sinusoiditis and diffuse intra-sinusoidal fibrin deposition. These findings suggested that a thrombotic sinusoiditis followed by a local diffuse intra-vascular (intra-sinusoidal) coagulation could be the typical features of the SARS-CoV-2-related liver injury.

Fetal programming of COVID-19: may the barker hypothesis explain the susceptibility of a subset of young adults to develop severe disease?

The risk stratification of young adults between subjects who will develop a mild form COVID-19 and subjects who will undergo a severe disease remains inaccurate. In this review, we propose that the Barker hypothesis might explain the increased susceptibility to severe forms of COVID-19 in subjects who underwent intrauterine growth restriction (IUGR). In this paper evidence indicating an association between a low birth weight and an adult phenotype which might favor a severe outcome of SARS-CoV-2 infection are presented: lower lung functional capacity; increased respiratory morbidity; changes in fibrinogen and Factor VII serum levels and dysregulation of the hemostasis and thrombosis system; acquisition of a pro-thrombotic phenotype; low nephron number, with decreased ability to sustain renal function and increased renal morbidity; heart remodeling, with a less efficient cardiac function; endothelial dysfunction, a risk factor for the insurgence of the multiple organ failure; remodeling of arteries, with changes in the elastic properties of the arterial wall, predisposing to the insurgence and progression of atherosclerosis; dysfunction of the innate immune system, a risk factor for immune diseases in adulthood. These data suggest that young and adult subjects born too small (IUGR) or too early (pre-terms) might represent a subgroup of "at risk subjects", more susceptible toward severe forms of COVID-19. Given that LBW may be considered a surrogate of IUGR, this phenotypic marker should be included among the indispensable clinical data collected in every patient presenting with SARS-COV-2 infection, irrespectively of his/her age.

Chronic intravascular coagulation in liver cirrhosis predicts a high hemorrhagic risk.

OBJECTIVE: In liver cirrhosis, a complex coagulopathy does exist. The aim was to investigate whether a possible chronic consumption coagulopathy is the underlying phenomenon of the disease. PATIENTS AND METHODS: We measured endogenous thrombin generation with and without thrombomodulin (ETP ratio) along with D-Dimer in a group of consecutive 282 cirrhotic patients. Fibrinogen, Platelet count and the Hemorrhagic score were previously computed in the same patients. The ETP ratio represents the resistance to the anticoagulant activity of TM and should be considered as an index of a procoagulant imbalance. RESULTS: ETP ratio and D-Dimer showed higher values in the cirrhotic patients when compared to controls thus showing a hypercoagulable state. When the patients were divided based on the Hemorrhagic score >7, we found that Fibrinogen, ETP ratio, D-Dimer and the platelet count were significantly different between the two groups. Again, when we considered ETP ratio >0.88, the median value of the cirrhotic patients, all parameters, were statistically different between the two groups. D-Dimer were higher while fibrinogen and platelet count were statistically lower in cirrhotic patients with higher ETP ratio values. Even when the same patients were divided based on their platelet count ( 100 x 109/L) the results showed a similar behavior. ROC curves showed significant AUCs when the hemorrhagic score was challenged against Fibrinogen, D-Dimer, Platelet count and ETP ratio. CONCLUSIONS: In liver cirrhosis hypercoagulable state is associated with an increase in D-Dimer levels along with a decrease in fibrinogen and platelet count thus indicating a low-grade intravascular coagulation which predicts a high hemorrhagic risk.

Vaccine-induced severe thrombotic thrombocytopenia following COVID-19 vaccination: a report of an autoptic case and review of the literature.

OBJECTIVE: Vaccine-induced immune thrombocytopenia (VITT) is a new syndrome occurring primarily in healthy young adults, with a female predominance, after receiving the first dose of ChAdOx1 nCoV-19 vaccine. We describe VITT syndrome characterized by severe thrombosis and thrombocytopenia found in our patient, with fatal outcome. CASE REPORT: A 58-year-old man, after 13 days from the first administration of ChAdOx1 nCoV-19 vaccine (AstraZeneca), presented with abdominal pain, diarrhea and vomitus. Laboratory tests revealed a severe thrombocytopenia, low fibrinogen serum levels and marked increase of D-dimer serum levels. The patient quickly developed a multiple organ failure, till death, three days after the hospital admission. RESULTS: At histology, in the lungs, interalveolar septa appeared thickened with microthrombi in the capillaries and veins. Interalveolar septa appeared thickened and showed vascular proliferation. Thrombi were detected in the capillaries of glomerular tufts. In the hearth, thrombi were observed in veins and capillaries. In the liver, voluminous fibrin thrombi were diffusely observed in the branches of the portal vein. Microthrombi were also found in the vasa vasorum of the wall of abdominal aorta. In the brain, microthrombi were observed in the capillaries of the choroid plexuses. Diffuse hemorrhagic necrosis was observed in the intestinal wall with marked congestion of the venous vessels. CONCLUSIONS: In our patient, the majority of data necessary for a VITT final diagnosis were present: thrombocytopenia and thrombosis in pulmonary, portal, hepatic, renal and mesenteric veins, associated with a marked increase of D-dimer serum levels. The finding of cerebral thrombosis in choroid plexuses, is a new finding in VITT. These features are suggestive for a very aggressive form of VITT.

Clinical history and gastrointestinal bleeding in patients taking oral anticoagulants.

BACKGROUND: Common risk factors for gastrointestinal bleeding (GIB) are advanced age and the use of antiplatelet or anticoagulants drugs for the prevention of cardiovascular diseases. METHODS: In this prospective real-world observational study, oral anticoagulated patients were recruited and followed between June 2013 and December 2019. The primary end-point was to evaluate a possible relationship between bleeding events and patients' clinical history of gastrointestinal disease prior to the start of the therapy. The secondary end-points were time of GIB appearance and the percentage of idiopathic or provoked events, i.e., bleeding due to a gastrointestinal disease. In case of GIB event all the patients were studied by means of endoscopic procedures. Cox regression was used to calculate the relative hazard ratios (HRs) of GIB for each considered clinical variable. RESULTS: 734 patients on both VKAs or DOACs were studied. Overall, 46 hemorrhagic events were recorded: 6 were major bleeding (0.42/100 patient-years) while 43 were clinically relevant non major bleeding (2.8/100 patient-years). The Cox regression analysis did not show any relationships among GIB and the variables considered. CONCLUSION: The patients' clinical history is neither a predictor for GIB bleeding nor a guide to the choice of the oral anticoagulant to be administered. Routinely applying bleeding risk screening, such as occult blood in the stool, should be added to the periodic laboratory checks for early recognition of patients at higher risk of GIB.

Infectious agents including COVID-19 and the involvement of blood coagulation and fibrinolysis. A narrative review.

OBJECTIVE: Platelets, blood coagulation along with fibrinolysis are greatly involved in the pathophysiology of infectious diseases induced by bacteria, parasites and virus. This phenomenon is not surprising since both the innate immunity and the hemostatic systems are two ancestral mechanisms which closely cooperate favoring host's defense against foreign invaders. However, the excessive response of these systems may be dangerous for the host itself. MATERIALS AND METHODS: We searched and retrieved the articles, using the following electronic database: MedLine and Embase. We limited our search to articles published in English, but no restrictions in terms of article type, publication year, and geography were adopted. RESULTS: The hemostatic phenotype of the infectious diseases is variable depending on the points of attack of the different involved pathogens. Infectious diseases which show a prothrombotic phenotype are bacterial sepsis, SARS-CoV-2 and malaria. However, among the bacterial sepsis, Yersinia Pestis is characterized by a profibrinolytic behavior. On the contrary, the hemorrhagic fevers, due to Dengue and Ebola virus, mainly exploit the activation of fibrinolysis secondary to a huge endothelial damage which can release a large amount of t-PA in the early phase of the diseases. CONCLUSIONS: Blood coagulation and fibrinolysis are greatly activated based on the strategy of the different infectious agents which exploit the excess of response of both systems to achieve the greatest possible virulence.

Heparins and 2019-nCoV infection: a narrative review.

OBJECTIVE: Patients with 2019-nCoV infection have a high risk to develop venous thrombotic events. Several guidelines recommend the use of either unfractionated heparin or low molecular weight heparins in preventing thrombotic events in these patients. However, results from clinical studies, so far published, reached controversial conclusions on heparin efficacy in this kind of patients since the incidence of venous thromboembolism remains high despite prophylaxis. This narrative review aims to provide an overview of the antiviral and anti-inflammatory properties of heparins and their efficacy and safety in SARS-CoV-2 medical ward-patients. Moreover, anatomical findings and ongoing trials are also reported. Finally, this narrative review tries to explain why heparins fail to prevent venous thrombosis. MATERIALS AND METHODS: We searched for the most relevant published studies on heparins and 2019-nCoV infected patients using the MEDLINE electronic database in the period between January and December 2020. Articles were preliminarily defined as eligible if they: a) were in English language, b) enrolled 250 or more medical ward-patients and 100 or more ICU-patients, c) reported results on patients treated with heparins in a percentage of at least 70% and d) performed an objectively confirmed diagnosis of VTE. RESULTS: Data from medium to large scientific studies show that the incidence of venous thrombotic events in medical ward-patients with SARS-CoV-2 vary between 0% and 8.3%, while this rate is higher, from 6.2% to 49%, in Intensive Care Unit-patients. However, heparins reduce the mortality rate in these patients of about 50%. Histological findings show that thrombosis could affect capillaries, main and small-mid-sized vessels, and it is associated with diffuse alveolar damage. CONCLUSIONS: Heparins have anti-inflammatory and anti-viral properties, which may be of help in reducing mortality in SARS-CoV-2 patients. Failure of heparins at prophylactic dosages in preventing VTE, especially in ICU-patients, could be due to the severity of the disease. Data on the use of heparins in an early phase of the 2019-nCoV infection are still lacking.

Scanning electron microscopy of lung disease due to COVID-19 - a case report and a review of the literature.

OBJECTIVE: The ongoing Coronavirus pandemic (COVID-19) showed similar characteristics with the severe acute respiratory syndrome (SARS). In the most compromised cases, COVID-19 infection leads to death due to severe respiratory complications. COVID-19-related acute respiratory distress syndrome (ARDS) is the primary cause of death in these patients. In the present study, we show an ultrastructural analysis on the lungs of a patient affected by COVID-19. PATIENTS AND METHODS: Lung specimens obtained at autopsy from a 63-years old patient affected by COVID-19 were fixed in 1% paraformaldehyde. Slices of 300 µm thickness were dehydrated and dried by Critical Point Drying in CO2. Slices were covered with a conductive gold film approximately 30 nm thick and observed at a Zeiss Sigma 300 SEM FEG in the secondary electron (SE) and backscattered electron (BSE) modes. As case control a lung biopsy from a 60-year-old man was considered. RESULTS: At low power in all COVID-19 lung specimens severe changes in the pulmonary architecture were found, due to the collapse of air spaces. Moreover, alveolar cavities were covered by large membranes. At high power, alveolar membranes showed a fibrillar structure, suggestive of a loose network of fibrin. It has been also found that intra-alveolar red blood cells were frequently present in the alveolar spaces, surrounded by a reticular fibrin network, suggestive for fibrin-hemorrhagic alveolitis. Alveolar changes were constantly associated with pathological features related to the pulmonary vessels. Vascular changes were prominent, including endothelial damage and thrombosis of large pulmonary vessels. Fibrinous microthrombi were frequently detected in the inter-alveolar septal capillaries. In addition, it has been frequently detected capillary proliferation in the alveolar septa with finding suggestive for intussusceptive neo-angiogenesis. CONCLUSIONS: In conclusion, our electron microscopy analysis showed that COVID-19-related lung disease is characterized by a substantial architectural distortion, with the interactions between alveolar and vascular changes. Intra-alveolar hyaline membranes are associated with macro- and micro-thrombotic angiopathy, ending with capillary proliferation. The new blood vessel formation originates from the septa and extends into the surrounding parenchyma. Our findings confirm previous reports on the specificity of the multiple and complex morphological pattern typical, and apparently specific, of COVID-19-related lung disease.

Molecular pathways triggered by COVID-19 in different organs: ACE2 receptor-expressing cells under attack? A review.

OBJECTIVE: In human pathology, SARS-CoV-2 utilizes multiple molecular pathways to determine structural and biochemical changes within the different organs and cell types. The clinical picture of patients with COVID-19 is characterized by a very large spectrum. The reason for this variability has not been clarified yet, causing the inability to make a prognosis on the evolution of the disease. MATERIALS AND METHODS: PubMed search was performed focusing on the role of ACE 2 receptors in allowing the viral entry into cells, the role of ACE 2 downregulation in triggering the tissue pathology or in accelerating previous disease states, the role of increased levels of Angiotensin II in determining endothelial dysfunction and the enhanced vascular permeability, the role of the dysregulation of the renin angiotensin system in COVID-19 and the role of cytokine storm. RESULTS: The pathological changes induced by SARS-CoV-2 infection in the different organs, the correlations between the single cell types targeted by the virus in the different human organs and the clinical consequences, COVID-19 chronic pathologies in liver fibrosis, cardiac fibrosis and atrial arrhythmias, glomerulosclerosis and pulmonary fibrosis, due to the systemic fibroblast activation induced by angiotensin II are discussed. CONCLUSIONS: The main pathways involved showed different pathological changes in multiple tissues and the different clinical presentations. Even if ACE2 is the main receptor of SARS-CoV-2 and the main entry point into cells for the virus, ACE2 expression does not always explain the observed marked inter-individual variability in clinical presentation and outcome, evidencing the complexity of this disorder. The proper interpretation of the growing data available might allow to better classifying COVID-19 in human pathology.

A "Catastrophic" Heparin-Induced Thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a transient, antibody-mediated thrombocytopenia syndrome that usually follows exposure to unfractioned heparin (UFH) or low-molecular-weight heparin (LMWH). In contrast to other pathological conditions which lead to thrombocytopenia and bleeding complications, HIT results in a paradoxical prothrombotic state. It is caused by antibodies directed to complexes containing UFH or LMWH and a self-platelet protein: the platelet factor 4 (PF4). The heparin-PF4 immune complex leads to activation of platelets, monocytes, and endothelial cells which release procoagulant proteins and tissue factor with subsequent blood coagulation activation. Case Report. We describe the case of a woman undergone to knee replacement and affected by urosepsis who developed a HIT after exposure to enoxaparin. The thrombotic burden was very impressive involving the arterial and venous cerebral vessel and the venous pulmonary, hepatic, and inferior legs vascular beds. The patient was successfully treated with fondaparinux without recurrent thrombosis or bleeding. The clinical scenario could be named "catastrophic HIT" like the catastrophic antiphospholipid syndrome since they have a similar pathogenetic mechanism involving both platelets and monocytes procoagulant activities and a similar clinical manifestation with a life-threatening multiple arterial and/or venous thromboses. CONCLUSION: Patients presenting with HIT could show a very impressive thrombotic burden resembling to that of the catastrophic antiphospholipid syndrome. A careful differential diagnosis should be made towards other pathological conditions which lead to thrombocytopenia to avoid an unnecessary and potentially harmful platelet transfusion. Although fondaparinux is off-label, its use in patients with HIT is simple and seems to be effective.

Clot wave analysis and thromboembolic score in liver cirrhosis: two opposing phenomena.

INTRODUCTION: Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are abnormal but unreliable in cirrhotic patients to express their risk of bleeding. However, these patients may also suffer from thrombotic episodes. In order to investigate the dynamics of the formation of fibrin, the clot waveform analysis (CWA) of aPTT was studied together with a score for the evaluation of the thromboembolic risk. METHODS: CWA in terms of velocity (1st derivative), acceleration (2nd derivatives) and density (Delta) of aPTT and the Padua Prediction Score (PPS) for venous thromboembolism were studied in 191 cirrhotic patients. RESULTS: CWA values were lower in the cirrhotic patients when compared to the control groups. However, Delta, 1st and 2nd derivatives were higher in cirrhotic patients with elevated PPS in comparison to those with a low PPS. The 1st derivative was significantly associated with a high PPS score (>4): OR: 2.66, CI: 95% 1.23-5.78. CONCLUSIONS: Two opposing tendencies seem to be present in cirrhotic disease: the first shows a weakness of clot formation while the second a predisposition towards thrombosis, identified by the PPS.