Valeria Rossetto

Prospective evaluation of anticoagulation and transjugular intrahepatic portosistemic shunt for the management of portal vein thrombosis in cirrhosis

There is no established management algorithm for portal vein thrombosis (PVT) in cirrhotic patients. The aim of our study was to prospectively evaluate anticoagulation and transjugular intrahepatic portosystemic shunt (TIPS) to treat PVT.

Increased anticoagulant response to low-molecular-weight heparin in plasma from patients with advanced cirrhosis

Summary.  Introduction:  Cirrhotic patients may present thrombotic complications that warrant anticoagulant therapy. However, the efficacy of low‐molecular‐weight heparin (LMWH) in this clinical setting is still unclear.

Whole blood coagulation assessment using rotation thrombelastogram thromboelastometry in patients with acute deep vein thrombosis

Common tests for the assessment of blood coagulation in the acute phase of deep vein thrombosis are of limited value for the evaluation of the associated hypercoagulability. The new rotation thromboelastometry by rotation thrombelastogram has the potential to provide information on whole blood clot formation and prothrombotic state in patients with acute deep vein thrombosis. Rotation thrombelastogram parameters were evaluated in whole blood of 30 patients with a first episode of acute deep vein thrombosis and 40 healthy controls. The effect of factor VIII and fibrinogen levels on rotation thrombelastogram assays was also assessed in the study population and in a model of blood supplemented by increasing amounts of fibrinogen. All assays performed were consistent with a remarkable hypercoagulable profile in deep vein thrombosis patients as compared with controls. In particular, maximum clot firmness and the area under curve values, which are expected to better correlate with the hypercoagulable state in the acute phase of deep vein thrombosis, were significantly higher in patients than in controls. As expected, fibrinogen was shown to be one of the main determinants of the hypercoagulability in rotation thrombelastogram assays. In a small subset of acute deep vein thrombosis patients, inherited thrombophilia had no influence on rotation thrombelastogram parameters. The new rotation thrombelastogram thromboelastometry is a useful tool to detect acute deep vein thrombosis-related hypercoagulability. Prospective studies are needed to define the potential applications of rotation thrombelastogram in the management of deep vein thrombosis patients.

Factor VIIa-antithrombin complexes in patients with arterial and venous thrombosis

Antithrombin (AT), in the presence of heparin, is able to inhibit the catalytic activity of factor VIIa bound to tissue factor (TF) on cell surfaces. The clinical meaning of FVIIa-AT complexes plasma levels is unknown. It was the objective of this study to evaluate FVIIa-AT complexes in subjects with thrombosis. Factor VIIa-AT complexes plasma levels in 154 patients consecutively referred to our Department with arterial or venous thrombosis and in a group of 154 healthy subjects, were measured. Moreover, FVIIa-AT complexes were determined in: i) n = 53 subjects belonging to 10 families with inherited factor VII deficiency; ii) n = 58 subjects belonging to seven families with AT deficiency; iii) n = 49 patients undergoing oral anticoagulant therapy (OAT). Factor VIIa-AT levels were determined by a specific ELISA kit (R&D, Diagnostica Stago, Gennevilliers, France). Factor VIIa-AT complexes mean plasma levels were lower in patients with either acute arterial (136 +/- 40 pM) or venous (142 +/- 53 pM) thrombosis than subjects with previous thrombosis (arterial 164 +/- 33 pM and venous 172 +/- 61 pM, respectively) and than healthy controls (156 +/- 63 pM). Differences between acute and previous thrombosis, were statistically significant (p < 0.05). Subjects with inherited and acquired (under OAT) factor VII deficiency had statistically significant lower FVIIa-AT complexes plasma levels (80 +/- 23 pM and 55 +/- 22 pM, respectively) than controls (150 +/- 51 pM, p < 0.0001 and 156 +/- 63 pM, p < 0.00001, respectively). Factor VIIa-AT complexes are positively correlated with plasma factor VII/VIIa levels. Further investigations are needed to verify the possible role of higher FVIIa-AT complex plasma levels in predicting hypercoagulable states and thrombosis.

Homozygous F5 deep-intronic splicing mutation resulting in severe factor V deficiency and undetectable thrombin generation in platelet-rich plasma

Summary.  Background: Coagulation factor (F) V deficiency is associated with a bleeding tendency of variable severity, but phenotype determinants are largely unknown. Recently, we have shown that three patients with undetectable plasma FV and mild bleeding symptoms had sufficient residual platelet FV to support thrombin generation in platelet‐rich plasma (PRP). Therefore, we hypothesized that FV‐deficient patients with severe bleeding manifestations may lack platelet FV. Objectives: To characterize a FV‐deficient patient with a severe bleeding diathesis. Patients/Methods: We performed FV mutation screening and functional studies in a 31‐year‐old male (FV:C < 1%) with umbilical bleeding at birth, recurrent hemarthrosis and muscle hematomas, and a recent intracranial hemorrhage. Results: The proband was homozygous for a deep‐intronic mutation (F5 IVS8 +268A→G) causing the inclusion of a pseudo‐exon with an in‐frame stop codon in the mature F5 mRNA. Although platelet FV antigen was detectable by immunoprecipitation followed by Western blotting, no FV activity could be demonstrated in the proband’s plasma or platelets with a prothrombinase‐based assay. Moreover, no thrombin generation was observed in PRP triggered with 1–50 pm tissue factor (even in the presence of platelet agonists), whereas an acquired FV inhibitor was excluded. Clot formation in the proband’s whole blood, as assessed by thromboelastometry, was markedly delayed but not abolished. Conclusions: This is the first report of a pathogenic deep‐intronic mutation in the F5 gene. Our findings indicate that the minimal FV requirement for viability is extremely low and suggest that thrombin generation in PRP may predict bleeding tendency in patients with undetectable plasma FV.

Whole blood rotation thromboelastometry (ROTEM®) profiles in subjects with non-neoplastic portal vein thrombosis

The coagulation pattern and the determinants of portal vein thrombosis (PVT), both in patients with and without cirrhosis, are still largely unknown. The aim of this study was to evaluate whole blood thromboelastometry profile, performed by ROTEM®, of both cirrhotic and non-cirrhotic subjects with PVT. Two different groups were considered: i) 14 non-cirrhotic PVT patients, ii) 35 cirrhotic patients with PVT. Controls were sex- and age-matched healthy volunteers and cirrhotic subjects without PVT, respectively. ROTEM® assays (i.e. INTEM, EXTEM, NATEM, and FIBTEM) and traditional coagulative parameters (i.e. platelet count, PT/INR, aPTT, and fibrinogen) were performed on blood samples from each subject. There were no significant differences in ROTEM® profile, as for INTEM, EXTEM, and NATEM assays, and in traditional coagulative parameters, between PVT patients, both with and without cirrhosis, and control groups. Interestingly, Maximum Clot Firmness (MCF) in FIBTEM was significantly higher in non-cirrhotic PVT patients (19 mm) than in healthy volunteers (11 mm, p<0.05). The amplitude of MCF in FIBTEM revealed to be a useful tool to discriminate non-cirrhotic subjects with PVT from those without thrombotic events. Larger prospective studies are needed to evaluate the relevance of the association between the alterations of ROTEM® profiles and PVT in cirrhotic patients.

The role of antiphospholipid antibodies toward the protein C/protein S system in venous thromboembolic disease

The association between venous thromboembolism (VTE) and antibodies anti-Protein C (PC)/Protein S (PS) is still uncertain. We performed a case-control study to determine the risk of VTE related to the presence of these auto-antibodies considered independently of the presence of lupus anticoagulant (LAC) or anti-cardiolipin antibodies (ACA). One hundred thirty-five patients with idiopathic VTE and 164 healthy subjects were enrolled. Anti-PC and anti-PS antibodies (both IgG and IgM) were assessed using commercially available ELISA kits. Among cases there was a higher prevalence of elevated anti-PC IgM antibodies than in controls (OR 2.44, 95%CI 1.00-5.94). The presence of anti-PC IgG and anti-PS IgG and IgM antibodies was also higher in cases than in controls, but the difference was not statistically significant. Only five patients had both anti-PC or anti-PS antibodies and LAC or ACA. We performed a stepwise multivariate logistic regression analysis showing that anti-PC IgM>958 percentile was a significant predictor of VTE after adjustment for LAC or ACA (OR 2.52, 95%CI 1.01-6.24)). Larger prospective studies are needed to confirm this finding.

An association between residual vein thrombosis and subclinical atherosclerosis: Cross-sectional study

BACKGROUND The association between venous and arterial thrombotic disorders is still unclear. We assessed the association between residual vein thrombosis (RVT) and subclinical atherosclerosis in a cohort of patients with unprovoked (or associated with weak risk factors) proximal deep-vein thrombosis (DVT). METHODS In a multicenter cross-sectional study, consecutive patients over 40years free from atherosclerotic disorders received the ultrasound assessment of the leg vein system and that of carotid arteries approximately three months after an episode of proximal DVT. In each center the evaluation was done by two independent assessors. The presence of RVT was defined as the incompressibility of at least 4mm in either the popliteal or the common femoral vein, and that of subclinical atherosclerosis as the presence of increased (>0.9mm) intima-media tickness (IMT) and/or carotid plaques. RESULTS Out of 252 patients (mean age, 67; males, 53%; unprovoked, 77%), the presence of RVT was found in 139 (55.2%). An increased IMT was shown in 76 (54.7%) patients with and in 35 (31.0%) without RVT (p<0.001). At least one carotid plaque was found in 80 (57.6%) patients with and in 36 (31.9%) without RVT (p<0.001). After adjusting for the baseline characteristics, the odds ratio of subclinical atherosclerosis (increased IMT and/or carotid plaques) was 2.8 (95% CI, 1.6 to 4.7). CONCLUSION The ultrasound detection of RVT after an episode of proximal DVT that is either unprovoked or triggered by weak risk factors is associated with a higher prevalence of subclinical atherosclerosis. These findings may have implications for patient prognosis.

Physicians’ compliance with the Padua Prediction Score for preventing venous thromboembolism among hospitalized medical patients

Hospitalization for acute medical illnesses confers an 8-fold increased risk of venous thromboembolic (VTE) disorders that persists for up to 3 months and is even higher after discharge than during in-hospital stay [1]. However, in spite of strong evidence in favor of thromboprophylaxis [2–4], several observation studies from various countries found that less than 50% of admitted medical patients at risk receive prophylaxis against VTE [5–8]. We have recently identified and validated a suitable and effective risk assessment model, the Padua Prediction Score (PPS), for optimal stratification of the thrombotic risk in hospitalized medical patients [9]. Its implementation in the Departments of Internal Medicine has recently been suggested by the latest ACCP consensus guidelines [10]. For the purpose of that investigation, attending physicians were not informed about the thrombotic risk of their patients and, as a result, less than 40% managed their patients correctly [9]. In an attempt to assess whether awareness of the thrombotic risk – as assessed with the PPS – has the potential to increase the rate of appropriate thromboprophylaxis in high-risk medical patients, we performed a second prospective investigation within the same framework as the first. On this occasion, we alerted the attending physicians to the thrombotic risk of their patients by tracing a well visible red line on the clinical chart of those who were at high risk. In addition, for further confirmation that the adoption of the PPS has the potential to improve patients’ outcome, we registered the thrombotic and hemorrhagic events occurring up to 90 days after recruitment in the high-risk patients. Any decisions concerning use and timing of prophylaxis were left to the discretion of the attending physicians. The investigation was approved by the Ethical Board of the University Hospital of Padua. Out of 1600 consecutive patients admitted to the Second Division of Internal Medicine of the University Hospital of Padua (Italy) between January 2010 and December 2011, 797 were excluded due to indications for anticoagulant treatment (740), contraindications for pharmacological prophylaxis (40), failure to give informed consent (10) or difficulties in obtaining follow-up information (8). Accordingly, 803 patients were recruited, of whom 296 (39.6%) were at high risk and 507 at low risk of VTE based on the PPS. Table 1 shows the main clinical features of the high-risk patients. Consistent with the previous investigation [8], prescriptions were regarded as adequate if enoxaparin 4000 U, dalteparin 5000 U or fondaparinux 2.5 mg were administered once a day within 48 h of hospital admission and for at least 80% of the hospital stay. Of the 296 high-risk patients, 262 (88.5%) received adequate pharmacological prophylaxis during hospitalization, this proportion being more than twice as high as that (186/469, 39.6%; P < 0.00001) recorded in the previous study [8]. The remaining 34 (11.5%) were either not treated or received inadequate prophylaxis. The median duration of prophylaxis during hospital stay was 12 days (interquartile range, 3–15). Thromboprophylaxis was continued after discharge in 50 patients (19.1%) for variable periods (ranging from 1 to 5 weeks). Thromboprophylaxis was also administered in 15 (2.9%) low-risk patients. Patients developing a clinical suspicion of DVT and/or PE were diagnosed by means of pre-test clinical probability and D-dimer [11,12]. Those with low pre-test probability and negative D-dimer were regarded as free from complications. For all other combinations, objective tests were performed in order to confirm or exclude the clinical suspicion (compression ultrasonography of the whole deep vein system in the case of suspected DVT; spiral CT or V/Q scanning of the lungs in the case of suspected PE) with the use of widely accepted diagnostic criteria. In the event of death, the diagnosis of PE was accepted if it was Correspondence: Paolo Prandoni, Department of Cardiothoracic and Vascular Sciences, Clinica Medica 2, University of Padua, Via Giustiniani 2, 35128 – Padua, Italy. Tel.: +39 49 8212656; fax: +39 49 8218731. E-mail: paoloprandoni@tin.it

Factor VIIa-antithrombin complexes in patients with non-neoplastic portal vein thrombosis with and without cirrhosis.

Portal vein thrombosis (PVT) is caused by local and systemic prothrombotic risk factors. In this case‐control study, we evaluated the use of the Factor VIIa‐antithrombin complex (FVIIa‐AT) complex assay as a hypercoagulability marker in patients with PVT.