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.

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.

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.

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.

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.

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.

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.

Prevalence and significance of anti-prothrombin (aPT) antibodies in patients with Lupus Anticoagulant (LA)

OBJECTIVE

Anti-prothrombin (aPT) antibodies have been found in Lupus Anticoagulant (LA) positive patients. Their prevalence and relative contribution to thromboembolic risk in LA-positive patients is not well defined. The aim of this study was to determine their presence and association with thromboembolic events in a large series of patients with confirmed LA.

METHODS

Plasma from LA-positive patients was collected at Thrombosis Centers and sent to a reference central laboratory for confirmation. Positive plasma was tested using home-made ELISA for the presence of aPT and anti-beta(2)GPI antibodies.

RESULTS

LA was confirmed in 231 patients. Sixty-one of 231 (26%, 95%CI 22-33) LA positive subjects were positive for IgG aPT and 62 (27%, 95% CI 21-33) were positive for IgM aPT antibodies. Clinical features of Antiphospholipid Syndrome (APS) were not associated with the presence of IgG aPT [43 APS in 61 (70%) positive and 109 APS in 170 (64%) negative IgG aPT subjects, p=ns] or IgM aPT. Rate of positivity of IgG and IgM a beta(2)GPI was significantly higher than that of IgG and IgM aPT. Clinical events accounting for APS occurred in 97 of 130 (75%) IgG a beta(2)GPI positive and in 55 of 101 (54%) IgG a beta(2)GPI negative patients (OR 2.4, 95% CI 1.4 to 4.3, p=0.002). No significant association with clinical events in patients positive for both IgG aPT and IgG a beta(2)GPI as compared to those positive for one or another test was found. When patients negative for both IgG aPT and IgG a beta(2)GPI (LA positive only) were compared with remaining patients, a significantly lower association with clinical events was found (OR=0.4, 95% CI: 0.2 to 0.7, p=0.004).

CONCLUSIONS

As compared to IgG a beta(2)GPI, the prevalence of IgG aPT in patients with LA is significantly lower and not associated with the clinical features of APS.

Clinical course of high-risk patients diagnosed with antiphospholipid syndrome

BACKGROUND

The characteristics and the clinical course of antiphospholipid syndrome (APS) in high-risk patients that are positive for all three recommended tests that detect the presence of antiphospholipid (aPL) antibodies have not been described.

METHODS

This retrospective analysis of prospectively collected data examined patients referred to Italian Thrombosis Centers that were diagnosed with definite APS and tested positive for aPL [lupus anticoagulant (LA), anti-cardiolipin (aCL), and anti-beta2-glycoprotein I (beta2GPI) antibodies]. Laboratory data were confirmed in a central reference laboratory.

RESULTS

One hundred and sixty patients were enrolled in this cohort study. The qualifying events at diagnosis were venous thromboembolism (76 cases; 47.5%), arterial thromboembolism (69 cases; 43.1%) and pregnancy morbidity (11 cases; 9.7%). The remaining four patients (2.5%) suffered from catastrophic APS. The cumulative incidence of thromboembolic events in the follow-up period was 12.2% (95% CI, 9.6-14.8) after 1 year, 26.1% (95% CI, 22.3-29.9) after 5 years and 44.2% (95% CI, 38.6-49.8) after 10 years. This was significantly higher in those patients not taking oral anticoagulants as compared with those on treatment (HR=2.4 95% CI 1.3-4.1; P<0.003). Major bleeding associated with oral anticoagulant therapy was low (0.8% patient/years). Ten patients died (seven were cardiovascular deaths).

CONCLUSIONS

Patients with APS and triple positivity for aPL are at high risk of developing future thromboembolic events. Recurrence remains frequent despite the use of oral anticoagulants, which significantly reduces the risk of thromboembolism.

Rheumatoid arthritis and thrombosis

OBJECTIVE

To review prevalence, risk factors and mechanisms of thrombosis in rheumatoid arthritis (RA).

METHODS

Available medical literature on PubMed was reviewed and relevant information summarized.

RESULTS

Patients affected by RA present an increased risk of thromboembolism, an important cause of morbidity and mortality. Research is focused on the role of disease-associated risk factors and predisposing conditions such as endothelial dysfunction, hypercoagulability, pro-thrombotic conditions, inflammatory markers, immobility and complications following major knee or hip replacement.

CONCLUSION

Thrombosis is a possible manifestation in RA patients. A number of factors are suspected to play a role in the increased thromboembolic risk. The mechanisms responsible for thrombosis in these patients remain unclear, however, the identification of the thrombophilic risk factors is clinically useful to determine in which patients occurrence is more likely.

Survey of lupus anticoagulant diagnosis by central evaluation of positive plasma samples

OBJECTIVE

To determine whether the diagnosis of lupus anticoagulant (LAC) in a large cohort of positive patients was confirmed at a reference laboratory.

METHODS

Over a 1-year period, each participating center collected samples from LAC-positive patients. Plasma was filtered and kept deep-frozen until it was sent on dry ice to the reference laboratory by express courier. Centers returned detailed laboratory information and clinical data from each patient. The reference laboratory screened plasma samples by diluted Russell viper venom time (dRVVT) and kaolin clotting time (KCT). When these were prolonged, 1:1 mixing studies were carried out, and confirmatory tests were performed as appropriate. Positive samples were further tested by thrombin time (TT). The presence of heparin was checked by measuring antifactor Xa activity when TT was prolonged. Negative samples were tested by activated partial thromboplastin time using hexagonal phospholipids.

RESULTS

Plasma samples from 302 patients from 29 anticoagulation clinics were analyzed. LAC was excluded in 71 samples (24%), because dRVVT and KCT screening test results were normal (34) or reversed to normal by mixing studies (35). The remaining two samples were considered negative because they contained heparin. LAC-negative patients showed different characteristics from those in whom diagnosis was confirmed. They were significantly older (49.7 vs. 45.0 years, P < 0.03), were more often first diagnosed (66% vs. 41%, P < 0.001), and were more frequently judged as mild in LAC potency (60% vs. 25%, P < 0.0001). Moreover, anticardiolipin and anti-beta(2)-glycoprotein I antibody values were more often normal in LAC-negative (82%) than in LAC-positive (42%) samples (P < 0.0001). LAC-positive samples identified by both dRVVT and KCT (146/231, 63%) showed a LAC potency that was significantly stronger than that in samples in which LAC diagnosis was made by a single test.

CONCLUSIONS

A false-positive LAC diagnosis is not uncommon across specialized centers. Patients' characteristics and a complete antiphospholipid antibody profile may help to identify these individuals.

The management of oral anticoagulant therapy: the patient's point of view

The aims of this study were to investigate on the general adhesion of the patients to oral anticoagulant therapy, and particularly on the quality of life of our patients, the doctor-patient relationship and the Centre-patient relationship. For this purpose we administered a questionnaire containing 17 main questions each with a maximum of 4 secondary questions. The questionnaire was administered to two groups of 127 and 137 oral anticoagulated patients (127 males and 137 females, mean age 55 +/- 19 years), followed at two Anticoagulation Clinics, in two Italian cities, Cagliari (Sardinia) and Padua (North East Italy). The cities differed in the number of patients monitored and the management modalities of anticoagulation. The results show that oral anticoagulant therapy does not limit the life-style of the patients. Only 11% of the patients complain of limitations to their daily life. Fifty-two percent believe their health has improved, and 87% are not afraid of negative consequences. The doctor-patient relationship is considered very important by 96% of patients. Seventy-eight percent refer to the Anticoagulation Clinic also for other health problems, 93% consider it important to be assessed by the doctor at the Anticoagulation Clinic, while 83% believe the doctor should always hand out the results personally. We conclude that in general oral anticoagulant therapy is accepted by the majority of patients, in spite of the need for periodic monitoring. The doctor-patient relationship should be taken into account, even in the case of a monitored, computer-assisted method of dose-adjustment.

Warfarin or acenocoumarol: which is better in the management of oral anticoagulants?

Warfarin is employed more frequently than acenocoumarol because of its longer half-life (36 h), theoretically providing more stable anticoagulation, and avoiding factor VII fluctuations that potentially occur during acenocoumarol treatment (half-life 10 h). The aim of our study was to compare acenocoumarol with warfarin in the same group of 103 patients who started oral anticoagulation with acenocoumarol and then changed to warfarin. In these patients we compared the previous period of six months on acenocoumarol treatment (July-December 1996) with a new six-month period on warfarin (July-December 1997). We wished to know whether warfarin could improve the quality and the stability of oral anticoagulation of our patients and whether there was a difference between the two drugs in the weekly mean dose per patient. Moreover in order to detect the possible daily fluctuation of factor VII, we evaluated a further group of 54 patients. A subgroup of these patients was treated with warfarin while another received acenocoumarol. In the first group of patients, 1,158 and 1,064 PTs were carried out with acenocoumarol and warfarin, respectively. The percentage of PTs in the therapeutic range was 59% with acenocoumarol and 62% with warfarin (p=0.4). The mean number of visits per patient was 12 and 11, and the mean number of visits in the therapeutic range was 7 and 7, respectively. The last check in file method did not show any difference between the two drugs. Overdose states were 51 (4.4%) with acenocoumarol and 30 (2.8%) with warfarin (p=0.4). A good correlation (r=0.92) was found between the acenocoumarol and the warfarin weekly mean dose. The mean warfarin/acenocoumarol weekly dose ratio was 2.08 (range: 1.25-3.30; CI 95%: 1.99-2.16). In the second group of patients, factor VII levels with both drugs were higher 24 h after administration than 16 h after, showing that their daily fluctuation was independent of the drug's half-life, since factor VII levels in patients with a low vitamin K intake were not increased. Our results showed that warfarin did not appear to be better than acenocoumarol in the performance of an Anticoagulation Clinic in terms of PTs within the therapeutic range per patient. It seems that the behaviour of factor VII was affected by the intake of vitamin K rather than by the short half-life of acenocoumarol.

Are prothrombin fragment 1 + 2 and thrombin-antithrombin complexes useful in the management of oral anticoagulant therapy?

We investigated the behavior of prothrombin fragment F1 + 2 and thrombin-antithrombin complexes in 70 patients treated with chronic anticoagulant therapy. Moreover, in a longitudinal study 37 patients were evaluated twice and 16 patients three times. Twenty-eight age- and sex-matched healthy subjects were also studied as a control group. Prothrombin fragment F1 + 2 or thrombin-antithrombin values among patients with different International Normalized Ratios, nor in the same patients studied two or three times. Our results confirm that oral anticoagulant treatment can effectively reduce thrombin activity. However, strong anticoagulation does not induce a further significant decrease in fragment F1 + 2 values. Therefore, we feel measurement of fragment F1 + 2 might be less useful than thought in optimizing oral anticoagulant therapy.

Comparison between recombinant and rabbit thromboplastin in the management of patients on oral anticoagulant therapy

The aim of this study was to compare recombinant thromboplastin (rTF, ISI = 0.82) with rabbit thromboplastin (RT, ISI = 1.46) in order to evaluate which performed better in our thrombosis centre. To this purpose we randomized 67 patients to be double-blind monitored in two groups for three months either with PT performed with RT or with PT performed with rTF. After this period each patient was shifted to the other group. We considered the following as end points of the study: percentages of PT results within the therapeutic range, number of visits and therapeutic dose adjustments per patient. The "last check in file" method was used to evaluate the laboratory quality of oral anticoagulation for both thromboplastins. The results show that there was no difference in the number of visits per patient between the two groups: 6.9 +/- 1.7 in the rTF group versus 7.3 +/- 1.9 in the RT group (p = 0.19). The variations of therapeutic dose per patient were not different in the two groups: the dose was changed once (range 0-8) in the rTF group and once (range 0-11) in the RT group (p = 0.15). The percentages of PT results within the therapeutic range were not different between the two groups. The "last check in file" method showed similar percentages in both groups: PT results in the therapeutic range were 67.2% in the RT group and 68.8% in the rTF group. We conclude that the two thromboplastins had a similar effect on the end points of the study in spite of the relatively high ISI of the RT.

Comparison between Recombinant and Rabbit Thromboplastin in the Management of Patients on Oral Anticoagulant Therapy

The aim of this study was to compare recombinant thromboplastin (rTF, ISI = 0.82) with rabbit thromboplastin (RT, ISI = 1.46) in order to evaluate which performed better in our thrombosis centre. To this purpose we randomized 67 patients to be double-blind monitored in two groups for three months either with PT performed with RT or with PT performed with rTF. After this period each patient was shifted to the other group. We considered the following as end points of the study: percentages of PT results within the therapeutic range, number of visits and therapeutic dose adjustments per patient. The “last check in file” method was used to evaluate the laboratory quality of oral anticoagulation for both thromboplastins. The results show that there was no difference in the number of visits per patient between the two groups: 6.9 ± 1.7 in the rTF group versus 7.3 ± 1.9 in the RT group (p = 0.19). The variations of therapeutic dose per patient were not different in the two groups: the dose was changed once (range 0-8) in the rTF group and once (range 0-11) in the RT group (p = 0.15). The percentages of PT results within the therapeutic range were not different between the two groups. The “last check in file” method showed similar percentages in both groups: PT results in the therapeutic range were 67.2% in the RT group and 68.8% in the rTF group. We conclude that the two thromboplastins had a similar effect on the end points of the study in spite of the relatively high ISI of the RT.