An in vitro model to mimic the thrombotic occlusion of small vessels in catastrophic antiphospholipid syndrome (CAPS).

Platelet activation and decrease in platelet count characterize the development of the most feared form of antiphospholipid syndrome (APS), i.e. catastrophic APS (CAPS). We aimed to assess if immuno-affinity purified anti-ß2-glycoprotein I (aß2GPI) antibodies enhance platelet activation inducing a significant flow obstruction in a platelet function analyzer (PFA). Affinity purified aß2GPI antibodies were obtained from 13 triple positive patients with a strong lupus anticoagulant (LA) and high titers of IgG anticardiolipin antibodies (aCL) and IgG aß2GPI. Platelet activation stimulated by adenosine diphosphate (ADP) in the presence or absence of aß2GPI was measured by the expression of P-selectin on platelet surface using flow cytometry. P-selectin expression remained close to baseline when normal whole blood was incubated with aß2GPI alone. When stimulated using aß2GPI combined with ADP, P-selectin expression (28.42 ± 5.15% vs. 20.98 ± 3.94%, p = 0.0076) was significantly higher than ADP alone. Closure time of normal whole blood passed through the PFA was significantly shorter using affinity purified aß2GPI than control IgG both in Col/ADP (160.1 ± 62.1 s vs. 218.6 ± 43.8 s; p = 0.021) and Col/EPI cartridges (149.5 ± 26.7 s vs. 186.9 ± 45.5 s; p = 0.030). Thus, platelet activation is enhanced by aß2GPI antibodies with a consequent premature closure in a PFA, possibly resembling that in microcirculation in patients with CAPS.

OC-15 - Risk factors for cancer development after idiopathic venous thromboembolism.

INTRODUCTION: Idiopathic venous thromboembolism (VTE) is associated with the risk of cancer but the risk factors for cancer development in such patients are still uncertain. AIM: To assess risk factors for the development of cancer after a standard course of anticoagulation in patients with first episode of idiopathic VTE. MATERIALS AND METHODS: Subjects were enrolled in the three large prospective multicentre studies: PROLONG (NEJM 2006) PROLONG II (Blood 2010) and DULCIS (Blood 2014). Women whose index event was hormone related were excluded from the analysis. The development of cancer was recorded during a 2-year follow-up. RESULTS: 1,805 patients were enrolled (M/F: 510/453), mean age: 62, median: 67; range:18-87 years). Cancer developed in 55 patients (3% ; 1.7% pt-years) of whom 15 (2.0%; 1.1% pt-years) had PE with or without DVT and 40 (3.8%; 2.1% pt-years) had DVT without PE (p=0.03). The development of cancer was associated with DVT without PE (HR:1.8; 95% CI: 1.1-3.3) and age >65 (HR: 2.5; 95%: 1.3-4.9). Among patients with DVT, with or without PE, the development of cancer was associated with the presence of residual vein obstruction>4mm (RVO) at compression ultrasound (HR: 1.8, 95% CI: 1.1-3.3) and age>65 (HR: 2.8; 95% CI: 1.3-6.2). CONCLUSIONS: Age>65 years, DVT without PE and the presence of RVO are significantly associated with the risk of developing cancer after a first episode of idiopathic VTE over a two-year follow-up.

Platelet and endothelial activation in catastrophic and quiescent antiphospholipid syndrome.

Antiphospholipid antibodies (aPL) seem to induce a prothrombotic state by activating endothelium and platelets, but no studies have evaluated systematically the effects of aPL from patients with the antiphospholipid syndrome (APS) in quiescent versus catastrophic phase. Our aims were to evaluate the in vitro effects on platelet activation of anti-ß2 glycoprotein I (anti-ß2GPI) antibodiesisolated from APS patientin either quiescent or catastrophic phase and to investigate ex vivo platelet and endothelial activation in patients with quiescent or catastrophic APS. Anti-ß2GPI antibodies were isolated from plasma of a pregnant woman in two different stages of APS (quiescent and catastrophic, respectively). They were co-incubated with washed platelets from healthy controls that were then challenged with TRAP-6 (thrombin receptor activating peptide 6) and the expression of P- selectin (P-sel) on platelets was assessed by flow cytometry. Moreover, plasma samples from six patients with quiescent, four with catastrophic APS and 10 controls were assessed for several markers of platelet and endothelial activation. The results showed that purified anti-ß2GPI antibodies co-incubated with platelets enhanced TRAP-6- induced platelet P-sel expression. Notably, anti-ß2GPI antibodies isolated during the catastrophic phase enhanced platelet P-sel expression more than antibodies isolated from the same patient in the quiescent stage of disease. Moreover, APS patients had significantly higher plasma levels of soluble (s) Psel, sCD40 ligand, soluble vascular cell adhesion molecule 1 and monocyte chemoattractant protein 1 than control subjects. In addition, sP-sel and von Willebrand factor activity were significantly higher during catastrophic than in quiescent phase.

Hospitalized patients with atrial fibrillation compared to those included in recent trials on novel oral anticoagulants: a population-based study.

BACKGROUND: Nonvalvular atrial fibrillation is associated with a substantial risk of stroke. Novel oral anticoagulants (NOACs) with predictable anticoagulant effect and no need for routine coagulation monitoring have recently shown good results when compared with warfarin in phase III clinical trials. OBJECTIVE: To describe clinical features and pharmacological treatments of a population-based cohort of patients with nonvalvular atrial fibrillation and ascertain whether they are comparable with those included in the three main phase III clinical trials on NOACs. RESULTS: Of the 2,862,264 subjects considered for this study 13,360 patients (0.47%) were recently discharged from the hospital with a diagnosis of nonvalvular atrial fibrillation. Mean age was 76.3 (SD 10.7), 49.8% were men and 64.6% were ≥75 years of age. 50% of patients were treated with warfarin and 44.1% with antiplatelet agents. The proportion of patients on antiplatelet therapy increased with age up to a rate of 54.3% in subjects ≥85 years. 92.9% of the studied cohort was on polypharmacy (mean 8 drugs/patient). Around 20% of the entire cohort was treated with amiodarone, a drug potentially interfering with NOACs, and 3.6% from a subgroup analysis had renal failure, which is an exclusion criterion in trials on NOACs. CONCLUSION: In patients recently discharged from the hospital with the diagnosis of nonvalvular AF, warfarin use decreases and aspirin treatment increases with patients' age. These patients are older, more frequently female, and on multiple medications. The benefit of NOACs in these subjects needs to be confirmed in phase IV clinical studies.

Residual venous obstruction, alone and in combination with D-dimer, as a risk factor for recurrence after anticoagulation withdrawal following a first idiopathic deep vein thrombosis in the prolong study.

OBJECTIVE: This study aims to assess the predictive value of residual venous obstruction (RVO) for recurrent venous thrombo-embolism (VTE) in a study using D-dimer to predict outcome. DESIGN: This is a multicentre randomised open-label study. METHODS: Patients with a first episode of idiopathic VTE were enrolled on the day of anticoagulation discontinuation when RVO was determined by compression ultrasonography in those with proximal deep vein thrombosis (DVT) of the lower limbs. D-dimer was measured after 1 month. Patients with normal D-dimer did not resume anticoagulation while patients with abnormal D-dimer were randomised to resume anticoagulation or not. The primary outcome measure was recurrent VTE over an 18-month follow-up. RESULTS: A total of 490 DVT patients were analysed (after excluding 19 for different reasons and 118 for isolated pulmonary embolism (PE)). Recurrent DVT occurred in 19% (19/99) of patients with abnormal D-dimer who did not resume anticoagulation and 10% (31/310) in subjects with normal D-dimer (adjusted hazard ratio: 2.1; p = 0.02). Recurrences were similar in subjects either with (11%, 17/151) or without RVO (13%, 32/246). Recurrent DVT rates were also similar for normal D-dimer, with or without RVO, and for abnormal D-dimer, with or without RVO. CONCLUSIONS: Elevated D-dimer at 1 month after anticoagulation withdrawal is a risk factor for recurrence, while RVO at the time of anticoagulation withdrawal is not.

Standardized low-molecular-weight heparin bridging regimen in outpatients on oral anticoagulants undergoing invasive procedure or surgery: an inception cohort management study.

BACKGROUND: Bridging therapy with low-molecular-weight heparin is usually recommended in patients who must stop oral anticoagulants before surgical or invasive procedures. To date, there is no universally accepted bridging regimen tailored to the patient's thromboembolic risk. This prospective inception cohort management study was designed to assess the efficacy and safety of an individualized bridging protocol applied to outpatients. METHODS AND RESULTS: Oral anticoagulants were stopped 5 days before the procedure. Low-molecular-weight heparin was started 3 to 4 days before surgery and continued for 6 days after surgery at 70 anti-factor Xa U/kg twice daily in high-thromboembolic-risk patients and prophylactic once-daily doses in moderate- to low-risk patients. Oral anticoagulation was resumed the day after the procedure with a boost dose of 50% for 2 days and maintenance doses afterward. The patients were followed up for 30 days. Of the 1262 patients included in the study (only 15% had mechanical valves), 295 (23.4%) were high-thromboembolic-risk patients and 967 (76.6%) were moderate- to low-risk patients. In the intention-to-treat analysis, there were 5 thromboembolic events (0.4%; 95% confidence interval, 0.1 to 0.9), all in high-thromboembolic-risk patients. There were 15 major (1.2%; 95% confidence interval, 0.7 to 2.0) and 53 minor (4.2%; 95% confidence interval, 3.2 to 5.5) bleeding episodes. Major bleeding was associated with twice-daily low-molecular-weight heparin administration (high-risk patients) but not with the bleeding risk of the procedure. CONCLUSIONS: This management bridging protocol, tailored to patients' thromboembolic risk, appears to be feasible, effective, and safe for many patients, but safety in patients with mechanical prosthetic valves has not been conclusively established.

The long-term risk of cancer in patients with a first episode of venous thromboembolism.

BACKGROUND: In patients with venous thromboembolism (VTE), 15-20% will have prevalent cancer when VTE is diagnosed but little is known about such patients' long-term risk, time course and predictors of new cancer. PATIENTS AND METHODS: We studied an inception cohort of patients with a first VTE who were not diagnosed with cancer within 3 months after VTE and who had follow-up for up to 120 months. We determined the annual risk for a new cancer [number of events and 95% confidence interval (CI)] per 100 person-years in all patients and in those with unprovoked VTE and identified predictors for new cancer. RESULTS: We studied 1852 patients with VTE who received anticoagulant therapy for 12 months (mean) and were followed for 4.2 years (mean). During follow-up, there were 105 (5.7%) patients diagnosed with new cancer during the period after the initial 3 months from diagnosis, for an annual risk of 1.32 (CI, 1.09-1.60) per 100 person-years. The risk for new cancer appeared uniform over time. The annual risk for new cancer was more than 2-fold higher in patients presenting with unprovoked compared with those with provoked VTE [1.76 (CI, 1.39-2.20) vs. 0.83 (CI, 0.58-1.16) per 100 person-years; P<0.001]. Clinical predictors for new cancer were increasing age [hazard ratio (HR), 1.23; CI, 1.05-1.44] and unprovoked VTE (HR, 1.86; CI, 1.21-2.87). CONCLUSION: In patients with a first VTE and without prevalent cancer, the risk for new cancer is about 1-2% per year, appears to be uniform over time, and is higher in patients with unprovoked VTE and those with advanced age.

Management of patients on long-term oral anticoagulant therapy undergoing elective surgery: survey of the clinical practice in the Italian anticoagulation clinics.

In the perioperative management of patients on long-term oral anticoagulant (OAC) therapy the problem is balancing the thromboembolic (TER) and the haemorrhagic risk (HR) in the perioperative period. The Federazione Centri per la diagnosi della trombosi e la Sorveglianza delle terapie Antitrombotiche (FCSA) activated an online registry from November 2001 to August 2003 in order to collect information on the management of these patients in Italy. Four hundred and eleven patients, undergoing elective major (18%) and minor surgery (82%), from 7 centres, were registered. Three hundred and ninety-nine out of 411 patients received LMWH either once a day (310 patients) or twice a day (89 patients) during OAC therapy discontinuation. Two thromboembolic (0.48%) and 16 bleeding events (7 major; 1.7%) were reported. Notwithstanding the lower doses of heparin (54.3 U/kg o.d. and 64.4 U/kg b.i.d.), the thromboembolic complications are in line with those reported in the literature. The data of this study suggest that the intervention with LMWH may be relevant only in the high-risk patients as already proposed by others.

Prevalence and clinical correlations of antibodies against six beta2-glycoprotein-I-related peptides in the antiphospholipid syndrome.

Two-hundred ninety five patients with the antiphospholipid syndrome (APS) were studied for the presence of antibodies against six anti-beta2GPI-related peptides Abs. The prevalence of a wide spectrum of clinical and laboratory parameters of APS was evaluated in all patients, and correlated with the presence of each anti-beta2GPI peptide antibody. The rates of the various antipeptides Abs ranged from 18.0 to 63.7%. Altogether, 87.1% of the patients had antibody reactivity against at least one of the six beta2GPI-related peptides. A high degree of simultaneous reactivity against several beta2GPI-peptides was found. Positive and negative correlations were found between several antipeptides Abs and the rates of thrombosis and fetal loss. Our results point to a heterogeneous activity of antiphospholipid Abs in APS patients, directed, often concurrently, against various epitopes of the beta2GPI molecule. Evaluation of APS patients for the presence of specific antipeptides Abs may be of a value in predicting the risk for future thrombotic and obstetrical complication, as well as for specific therapeutic purposes.

Diabetic ketosis activates lymphomonocyte-inducible nitric oxide synthase.

AIMS: Inappropriate production of nitric oxide (NO) may be responsible for the haemodynamic disturbances of diabetic ketoacidosis. We investigated whether this metabolic condition is associated with increased plasma nitrate (the stable oxidation product of NO) levels and NO synthase gene expression in lymphomonocytes. RESEARCH DESIGN AND METHODS: Plasma nitrate concentrations, lymphomonocyte-inducible nitric oxide synthase (iNOS) gene expression, tumour necrosis factor-alpha (TNF-alpha) and soluble thrombomodulin were measured in 11 Type 1 diabetic patients at baseline, during mild ketosis and after euglycaemia was re-established. RESULTS: During diabetic ketosis plasma nitrate concentrations were higher (18 (16-21) vs. 9 (7-11) micro mol/l; (95% lower-upper confidence interval) P < 0.05) than at baseline. At baseline lymphomonocyte iNOS mRNA expression and iNOS protein levels were undetectable, but in ketosis both were increased (both at P < 0.0001). After recovery from ketosis, NO3 concentration, iNOS mRNA, and iNOS expression (270 +/- 36%, mean +/- sd) decreased but not significantly. No significant changes were observed in either TNF-alpha or soluble thrombomodulin levels between the three conditions. CONCLUSIONS: Diabetic ketosis is associated with increased nitrate levels and the activation of iNOS expression in circulating lymphomonocytes, but it does not affect either the proinflammatory cytokine TNF-alpha or a marker of endothelial dysfunction such as thrombomodulin. Our data support the hypothesis that, during diabetic ketosis, alterations in NO homeostasis are present in circulating lymphomonocytes.

A comparison of the safety and efficacy of oral anticoagulation for the treatment of venous thromboembolic disease in patients with or without malignancy.

The optimal long-term treatment of acute venous thromboembolism (VTE) in patients with malignancy remains undefined. In particular, based on current evidence, it is uncertain whether secondary prophylaxis using standard intensity oral anticoagulant therapy is associated with higher risks of bleeding and recurrent thrombosis in patients with cancer than in those without cancer. This study compared the outcome of anticoagulation courses in 95 patients with malignancy with those of 733 patients without malignancy. All patients were participants in a large, nation-wide population study and were prospectively followed from the initiation of their oral anticoagulant therapy. Based on 744 patient-years of treatment and follow-up, the rates of major (5.4% vs 0.9%), minor (16.2% vs 3.6%) and total (21.6% vs 4.5%) bleeding were statistically significantly higher in cancer patients compared with patients without cancer. Bleeding was also a more frequent cause of early anticoagulation withdrawal in patients with malignancy (4.2% vs. 0.7%; p <0.01; RR 6.2 (95% CI 1.95-19.4). There was a trend towards a higher rate of thrombotic complications in cancer patients (6.8% vs. 2.5%; p = 0.058; RR 2.5 [CI 0.96-6.5]) but this did not achieve statistical significance. In the group of patients with cancer, the bleeding rate was high across the different INR categories and was independent of the temporally associated International Normalized Ratio (INR). In contrast, the bleeding rate was increased only with INR values greater than 4.5 in the group of patients without cancer. The rate of thrombotic events was significantly higher in both cohorts when the INR was less than 2.0. In conclusion, patients with malignancy treated with oral anticoagulants have a higher rate of bleeding and possibly an increased risk of recurrent thrombosis compared with patients without malignancy. Safer and more effective anticoagulant therapy is needed for this challenging group of patients.

Simple and safe method to prepare patients with prosthetic heart valves for surgical dental procedures.

Temporary discontinuation of high-intensity oral anticoagulant treatment is not recommended in patients undergoing dental surgery. This policy is not based on solid data from randomized clinical trials but on expert consensus. The alternative, i.e., to continue treatment and treat patients with tranexamic acid mouthwash, often is not applicable. A prospective cohort study was carried out to evaluate bleeding and thromboembolic complications in patients bearing prosthetic heart valves and registering International Normalized Ratio (INR) values between 2.0 and 4.5, who underwent dental procedures after a 2-day suspension of warfarin treatment. One hundred four consecutive patients receiving high-intensity anticoagulation underwent 123 dental procedures after 2 days' warfarin withdrawal. No major bleeding complications occurred in the week after the procedure; minor bleeding requiring local measures occurred in two patients. No thromboembolic events and no cases of bacterial endocarditis were recorded in the 3 months after the procedure. A mean decrease in INR by approximately 1.0 U (from 2.95+/-0,59 to 1.87+/-0,46) occurred after 2 days' warfarin suspension. Seven days after reinitiation of warfarin, INR values returned to the therapeutic range in 90% of cases. The calculated average time spent at INR less than 2.0 (critical value) was 28 hours. Two days' warfarin suspension is a simple and safe policy for patients with prosthetic heart valves undergoing dental surgery.

Low intensity warfarin therapy.

BACKGROUND AND OBJECTIVE: Several studies comparing different intensities of oral anticoagulant treatment have clearly shown a relationship between bleeding complications and prolongation of prothrombin time. In the early '50s, de Takats suggested that low-dose oral anticoagulants might be as effective as higher doses in preventing thrombosis, at a lower risk of bleeding. This review article examines the potential of low dose warfarin therapy. INFORMATION SOURCES: The authors have been working in this field, contributing original papers. In addition, the material examined in this article includes articles published in the journals covered by the Science Citation Index and MedLine. STATE OF ART AND PERSPECTIVES: The hypothesis that low-dose oral anticoagulants can be effective in preventing thrombosis was first proven by experiments in animal models, and showed that a prothrombin time ratio as low as 1.14 using rabbit brain thromboplastin was still able to confer some inhibition of experimental thrombosis. Low-dose or very low-dose warfarin were subsequently demonstrated to be effective in patients with morbid obesity and decreased antithrombin III functional and antigenic levels, in patients with indwelling catheters, in patients undergoing gynecological surgery, as well as in patients with stage IV breast cancer. Low-dose warfarin is also effective in the prevention of embolic strokes in patients with non-rheumatic atrial fibrillation. However, older patients (> 75 years), who have a very high risk of bleeding, might be safer taking a very low dose of warfarin (i.e., a daily dose of 1-1.25 mg). Moreover, after a period of run-in, a fixed, very low-dose warfarin schedule does not need further laboratory control, which is a factor that could contribute to the full acceptance of treatment by patients and could stimulate a broader prescription of warfarin for the primary prevention of stroke in older patients with nonrheumatic atrial fibrillation. Therefore, we have organized a multicenter clinical trial in which 1000 patients with non-rheumatic atrial fibrillation will be randomized to receive either a fixed mini-dose of warfarin or a standard dose. Positive results might permit the treatment of most older patients with non-rheumatic atrial fibrillation, creating a benefit for the community as a consequence of its effective prevention of disabling strokes.

A brief contact of native whole blood with adenosine diphosphate (ADP) promotes the release of the contents of platelet alpha granules but not dense bodies and increases platelet retention to glass bead columns.

We have previously demonstrated that a brief contact of native whole blood with ADP, promotes a dose dependent release of the contents of platelet alpha granules. In the present study we have shown that in our system there is not a parallel release of the contents of platelet dense bodies as measured by the release of serotonin (5 HT). This early and partial platelet activation determines an increase in platelet retention in glass bead columns. After exactly 15 seconds of activation of native whole blood from 6 healthy volunteers with ADP, in fact, there was a significant fall in the platelet count following the flow of native whole blood across glass beads. A significant decrease (from x = 182,000 +/- 13,700 to x = 120,000 +/- 8,00/microliters p less than 0.001) was present when the blood was stimulated with 0.4 microM ADP final concentration. These results suggest that early, partial platelet activation by ADP could facilitate their possible adhesion to a suitable surface exposed along the vascular tree.

Adenosine diphosphate (ADP)-induced alpha-granules release from platelets of native whole blood is reduced by ticlopidine but not by aspirin or dipyridamole.

A brief contact between native whole blood and ADP promotes a dose-dependent release of platelet alpha-granules without a fall in the platelet number. We assessed the "ex vivo" effect of three widely used antiplatelet drugs, aspirin dipyridamole and ticlopidine, on this system. Aspirin (a single 800 mg dose) and dipyridamole (300 mg/die for four days) had no effect, while ticlopidine (500 mg/die for four days) significantly reduced the alpha-granules release for an ADP stimulation of 0.4 (p less than 0.02), 1.2 (p less than 0.01) and 2 microM (p less than 0.01). No drug, however, completely inhibits this early stage of platelet activation. The platelet release of alpha-granules may be related to platelet shape change of the light transmission aggregometer and may be important "in vivo" by enhancing platelet adhesiveness and by liberating the platelet-derived growth factor.

Monitoring liver regeneration after right hepatectomy.

Factor VII coagulant, prothrombine time, fibrinogen, prealbumin and a fetoprotein have been evaluated in a patient operated on for right hepatectomy, in order to identify the best markers in prognosing liver regeneration. Factor VII and prothrombine time progressively increased, starting from the 5th-7th day, entering normal range by the 10th and demonstrated a good correlation with both liver scintiscan and ultrasonography. Prealbumin and fibrinogen did not provide any useful information and a fetoprotein levels progressively decreased, demonstrating the complete removal of the neoplastic tissue. Factor VII and prothrombine time seem therefore to be the most reliable markers, among those investigated in this study, of liver regeneration after partial hepatectomy.

The use of laser-nephelometry in evaluating fibrinogenaemia in patients with hepatocarcinoma and cirrhosis.

In the present study fibrinogen was assayed by the immunonephelometric method in 19 patients afflicted with hepatocarcinoma and 24 patients afflicted with cirrhosis. The two groups were similar in age, sex and presence of HbsAg. The incidence of values above the norm was significantly greater in patients with hepatocarcinoma (p less than 0.05). Then, the concentration of fibrinogen was measured in all using two other immunological methods (Laurell and Mancini) and two coagulative methods (Clauss and Ratnoff). A dysfibrinogenemia (an excess of fibrinogen assayed by immunological methods to be greater than 100 mg/dl with respect to biological methods). is more frequent using the Nephelometer-Clauss (p less than 0.01) and Mancini-Clauss (p less than 0.01) methods in patients with hepatocarcinoma with respect to those with cirrhosis. The study of the kinetics of antifibrinogen antigen-antibody reaction failed to show differences between patients with hepatocarcinoma or cirrhosis and normal subjects.