Thrombin generation and activated protein C resistance in the absence of factor V Leiden correlates with the risk of recurrent venous thromboembolism in women aged 18-65 years.

Identification of patients at high risk of recurrence after a first event of venous thromboembolism (VTE) remains difficult. Resistance to activated protein C (APC) is a known risk factor for VTE, but data on the risk of recurrence is controversial. We wanted to investigate whether APC resistance in the absence of factor V Leiden, determined with global coagulation test such as the thrombin generation assay, could be used as a marker for increased risk of recurrent VTE among women 18-65 years old after a first event of VTE. In a cohort of 243 women with a first event of VTE, plasma was collected after discontinuation of anticoagulant treatment and the patients were followed up for 46 months (median). Thrombin generation was measured via calibrated automated thrombography, at 1 pM and 10 pM of tissue factor (TF). In women without factor V Leiden (n=117), samples were analysed in the absence and in the presence of APC. Increase in ETP (endogenous thrombin potential) and peak height analysed in the presence of APC correlated significantly with higher risk of recurrence. At 1 pM, peak height correlated with increased risk of recurrence. In conclusion, high thrombin generation in the presence of APC, in women after a first event of VTE is indicative for an increased risk of a recurrence. We also found that thrombin generation at low TF (1 pM) is correlated with the risk of recurrence. Our data suggest that APC resistance in the absence of factor V Leiden is a risk factor for recurrent VTE.

Deep venous thrombosis after surgery for Achilles tendon rupture: a provoked transient event with minor long-term sequelae.

BACKGROUND: Deep venous thrombosis (DVT) occurs frequently in patients undergoing orthopedic surgery, but there is a lack of knowledge regarding long-term sequelae of DVT after different types of surgical procedures. OBJECTIVE: To describe the long-term effect of symptomatic (SDVT) and asymptomatic (ADVT) deep venous thrombosis on venous function and subsequent incidence of post-thrombotic syndrome (PTS) in patients who have undergone surgery for Achilles tendon rupture. PATIENTS/METHODS: This observational follow-up study includes 83 patients with postoperative DVT, examined after a mean of 7 years. There were two series of patients: 45 with SDVT and 38 with ADVT. In both series, more than 90% of the DVTs were limited to calf veins. Follow-up examinations comprised color duplex ultrasonography (CDU), strain-gauge plethysmography (SGP), clinical examination including scoring for venous disease and questionnaires for quality of life (QOL). RESULTS: A mild degree of PTS was found in 11% of the patients: 13% in SDVT and 8% in ADVT patients. The rate of recurrent ipsilateral DVT was 2%. Deep venous reflux was more common in patients with SDVT than in ADVT patients (84% vs. 55%, P < 0.01). Only a few patients had plethysmograpically abnormal findings without difference between the two groups. CONCLUSION: DVT after surgery for Achilles tendon rupture consists mainly of distal DVTs and are associated with a low risk for PTS. Deep venous reflux was more common in SDVT than in ADVT patients, probably as an effect of larger DVTs in the former group.

Asymptomatic deep venous thrombosis is associated with a low risk of post-thrombotic syndrome.

UNLABELLED: Post-thrombotic syndrome (PTS) is a well-recognized condition that develops after symptomatic deep venous thrombosis, but the clinical significance and late complications of asymptomatic deep venous thrombosis (ADVT) are unclear. OBJECTIVE: To determine whether ADVT following minor surgery affects venous function and contributes to the later development of PTS. PATIENTS/METHODS: The study included 83 patients operated on for Achilles tendon rupture; 38 patients with postoperative ADVT and 45 patients without (control group). The follow-up examinations five years after the operation comprised computerised strain-gauge plethysmography, colour duplex ultrasonography, clinical scoring of venous disease, and quality of life (QOL). RESULTS: Villalta scores, CEAP classification and QOL did not differ between groups. PTS (=Villalta score > or =5) was found in three ADVT patients (8%) and in two controls (4%). Ultrasonography revealed post-thrombotic changes in 55% of ADVT patients and in none of the controls. Deep venous reflux occurred in 22 ADVT patients and in three controls (P<0.001). There was no difference between groups in plethysmographic variables, demonstrating that the ultrasonographic abnormalities were of negligible haemodynamic significance. CONCLUSIONS: PTS is not a common sequel to ADVT after minor surgery. Although more than 50% of patients with ADVT developed post-thrombotic changes according to ultrasound, these changes did not result in haemodynamically significant venous dysfunction.

Primary deep vein thrombosis in the upper limb: A retrospective study with emphasis on pathogenesis and late sequelae.

BACKGROUND: Thrombosis of the upper extremity (UEDVT) is an uncommon disease with an incidence of 2-3% of all deep vein thromboses. The aim of this study was to determine the frequency of thrombophilia, post-thrombotic symptoms (PTS), and the rate of complications and recurrences in patients with primary UEDVT, which includes idiopathic and effort-related thrombosis. METHODS: Thirty-two patients with primary UEDVT were participants in the study. All patients with malignancies and intravenous devices were excluded. Two different scoring instruments - the Villalta and the DASH - were used to diagnose PTS, and a visual analogue scale (VAS) was used to estimate pain and disability. To evaluate working capacity, an arm exercise test was performed. Blood samples were taken for antithrombin, protein C and S deficiencies, antiphospholipid antibodies, mutation of factor V, fibrinogen, D-dimer, and von Willebrand factor antigen. RESULTS: None of the patients developed malignancy, pulmonary embolism, or recurrent UEDVT. Twenty-eight percent of the patients had mild to moderate PTS according to the scoring instruments. The arm exercise test and the VAS did not provide any additional information about the severity of PTS. The prevalence of thrombophilia was 40%; the most frequent disorders were the mutation of factor V (19%) and elevated fibrinogen (22%). CONCLUSIONS: This study supports the belief that primary UEDVT is a benign disorder with a low risk for recurrence but with a high frequency of PTS. For a majority of the patients, the underlying cause of the thrombotic event is unclear.

Addition of intravenous iron to epoetin beta increases hemoglobin response and decreases epoetin dose requirement in anemic patients with lymphoproliferative malignancies: a randomized multicenter study.

This randomized study assessed if intravenous iron improves hemoglobin (Hb) response and permits decreased epoetin dose in anemic (Hb 9-11 g/dl), transfusion-independent patients with stainable iron in the bone marrow and lymphoproliferative malignancies not receiving chemotherapy. Patients (n=67) were randomized to subcutaneous epoetin beta 30 000 IU once weekly for 16 weeks with or without concomitant intravenous iron supplementation. There was a significantly (P<0.05) greater increase in mean Hb from week 8 onwards in the iron group and the percentage of patients with Hb increase >or=2 g/dl was significantly higher in the iron group (93%) than in the no-iron group (53%) (per-protocol population; P=0.001). Higher serum ferritin and transferrin saturation in the iron group indicated that iron availability accounted for the Hb response difference. The mean weekly patient epoetin dose was significantly lower after 13 weeks of therapy (P=0.029) and after 15 weeks approximately 10 000 IU (>25%) lower in the iron group, as was the total epoetin dose (P=0.051). In conclusion, the Hb increase and response rate were significantly greater with the addition of intravenous iron to epoetin treatment in iron-replete patients and a lower dose of epoetin was required.

Post-thrombotic syndrome, recurrence, and death 10 years after the first episode of venous thromboembolism treated with warfarin for 6 weeks or 6 months.

BACKGROUND: The influence of the duration of anticoagulant therapy after venous thromboembolism (VTE) on the long-term morbidity and mortality is unclear. AIM: To investigate the long-term sequelae of VTE in patients randomized to different duration of secondary prophylaxis. METHODS: In a multicenter trial comparing secondary prophylaxis with vitamin K antagonists for 6 weeks or 6 months, we extended the originally planned 2 years follow-up to 10 years. The patients had annual visits and at the last visit clinical assessment of the post-thrombotic syndrome (PTS) was performed. Recurrent thromboembolism was adjudicated by a radiologist, blinded to treatment allocation. Causes of death were obtained from the Swedish Death Registry. RESULTS: Of the 897 patients randomized, 545 could be evaluated at the 10 years follow-up. The probability of developing severe PTS was 6% and any sign of PTS was seen in 56.3% of the evaluated patients. In multivariate analysis, old age and signs of impaired circulation at discharge from the hospital were independent risk factors at baseline for development of PTS after 10 years. Recurrent thromboembolism occurred in 29.1% of the patients with a higher rate among males, older patients, those with permanent triggering risk factor - especially with venous insufficiency at baseline - signs of impaired venous circulation at discharge, proximal deep vein thrombosis, or pulmonary embolism. Death occurred in 28.5%, which was a higher mortality than expected with a standardized incidence ratio (SIR) of 1.43 (95% CI 1.28-1.58), mainly because of a higher mortality than expected from cancer (SIR 1.83; 95% CI 1.44-2.23) or from myocardial infarction or stroke (SIR 1.28; 95% CI 1.00-1.56). The duration of anticoagulation did not have a statistically significant effect on any of the long-term outcomes. CONCLUSION: The morbidity and mortality during 10 years after the first episode of VTE is high and not reduced by extension of secondary prophylaxis from 6 weeks to 6 months. A strategy to reduce recurrence of VTE as well as mortality from arterial disease is needed.

Prednisolone inhibits cytokine-induced adhesive and cytotoxic interactions between endothelial cells and neutrophils in vitro.

We assessed whether prednisolone influenced the ability of human polymorphonuclear neutrophils (PMN) to adhere to and cause lysis of human umbilical vein endothelial cells (HUVEC) in vitro (as measured by the release of 51Cr). Pretreatment of the endothelium with IL-1beta or tumour necrosis factor-alpha (TNF-alpha) caused prominent endothelial E-selectin expression and endothelial hyperadhesiveness for neutrophils, as well as PMN-mediated cytotoxicity. All these processes were dose-dependently reduced when prednisolone was added to the assay system. This protective effect remained when HUVEC alone were pretreated with the drug prior to washing and cytokine activation. Likewise, when HUVEC cytotoxicity was induced by the nitric oxide (NO) donor S-nitroso-acetyl-penicillamine (SNAP), prednisolone reduced cell injury significantly. In contrast, prednisolone did not interfere with signalling systems between TNF-alpha-stimulated HUVEC and quiescent PMN such as IL-8 generation and release of cytosolic Ca2 + in the PMN. Thus, in this in vitro model of vasculitis, prednisolone dose-dependently reduced cytokine-induced E-selectin expression and HUVEC hyperadhesiveness for neutrophils, as well as reducing neutrophil-dependent cytotoxicity against HUVEC via NO-dependent steps.

Electrochemical detection of nitric oxide production in human polymorphonuclear neutrophil leukocytes.

The detection of nitric oxide (NO) release by human polymorphonuclear neutrophil leukocytes (PMNs) presents several difficulties, mainly due to concomitant production of O2- and H2O2, which could interfere with the measurements. A Nafion and nickel porphyrin-coated microelectrode was used to measure NO production in PMNs in vitro. It allowed detection of 6.3 +/- 1.9 nM NO in a PMN-containing system and was unaffected by added chemicals. Addition of the chemotactic oligopeptide f-met-leu-phe (fMLP; 100 nM) induced a NO release which reached a value of 71 +/- 30 pmol NO/10(6) PMN x ml(-1) 5 min after stimulation in the presence of SOD (150 U/ml). If SOD was omitted, the corresponding value was 36 +/- 20 pmol NO/10(6) PMN x ml(-1). Presence or absence of catalase did not alter the amount of NO measured. Addition of the NO-synthase inhibitor N(G)-monomethyl-L-arginine (LNMMA; 1 mM) reduced the current by 82 +/- 20%. These results agree with the rate of NO production in human PMNs when measured spectrophotometrically using the NO-dependent oxidation of oxyhaemoglobin to methaemoglobin. The NO production in human PMN was dependent on fMLP concentrations, but independent of cell-concentrations of 0.5-3.5 x 10(6)/ml. This paper shows that a electrochemical method, e.g. Nafion and porphyrin-coated microelectrode, is suitable for studies of NO release from stimulated human PMNs.

Unusual clinical presentation in a patient with myelodysplastic syndrome, with subsequent hematological remission and suppression of the malignant clone following treatment with cyclosporine A, erythropoietin and granulocyte colony-stimulating factor.

A 35-year-old female presented with isolated thrombocytopenia of autoimmune origin. One and a half years later, hypoplastic myelodysplastic (MDS) was diagnosed. Following treatment with cyclosporin A, erythropoietin and granulocyte colony-stimulating factor, the patient has achieved a sustained hematological remission which is still ongoing after 3 years. Furthermore, to the best of our knowledge, this is the third case described in the literature where treatment with cytokines alone or in combination with immunosuppressive agents has resulted in a long standing cytogenetic response in MDS.

Gamma interferon treatment of patients with chronic granulomatous disease is associated with augmented production of nitric oxide by polymorphonuclear neutrophils.

Treatment with gamma-interferon (IFN-gamma) is associated with reduced frequency and severity of infections in chronic granulomatous disease (CGD), but the mechanism is unknown. Since the inducible nitric oxide (NO) synthase can be amplified by IFN-gamma in murine macrophages, for example, we hypothesized that IFN-gamma might modulate NO release from polymorphonuclear neutrophils (PMNs) in patients with CGD. Eight patients with CGD and eight healthy controls were studied. Each patient was given either 50 or 100 microg of IFN-gamma per m2 on two consecutive days. The production of NO from N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMNs was assessed as the NG-monomethyl-L-arginine-inhibitable oxidation of oxyhemoglobin to methemoglobin in the presence of catalase and superoxide dismutase. Prior to IFN-gamma treatment, the PMNs from CGD patients produced 372 +/- 27 (mean +/- standard error of the mean) pmol of NO/10(6) PMNs at 45 min, while the control PMNs produced 343 +/- 44 pmol. On day 1 after IFN-gamma treatment, NO production increased to 132% +/- 25% of that for controls, and on day 3 it reached 360% +/- 37% (P < 0.001) of that for controls. On day 8, the values still remained higher, 280% +/- 78% more than the control values. Likewise, the bactericidal capacity of PMNs increased on day 3. The present data show that IFN-gamma treatment of CGD patients is associated with an increased production of NO from PMNs when activated by fMLP. Since these PMNs lack the capacity to produce superoxide anions, it is conceivable that this increase in NO release could be instrumental in augmenting host defense.

Activation of nitric oxide release and oxidative metabolism by leukotrienes B4, C4, and D4 in human polymorphonuclear leukocytes.

Because arachidonate metabolites are potent mediators of inflammation, we have studied the effects of leukotriene B4 (LTB4) and the cysteinyl leukotrienes C4 and D4 (LTC4 and LTD4) on the release of nitric oxide (NO), in vitro, by human polymorphonuclear granulocytes (PMN). Two independent and highly sensitive real-time methods were used for these studies, ie, the NO-dependent oxidation of oxyhemoglobin (HbO2) to methemoglobin and a NO-sensitive microelectrode. When activated with LTB4, LTC4, or LTD4, but not with other lipoxygenase products such as 5S-HETE, 5-oxo-ETE or 5S, 12S-diHETE, PMN produced NO in a stimulus- and concentration-dependent manner. The rank order of potency was LTB4 = LTC4 > LTD4, corresponding to 232 +/- 50 pmol of NO/10(6) PMN for 100 nmol/L LTB4 after 30 minutes. The kinetic properties of the responses were similar for all three leukotrienes with a maximum response at 13 +/- 3 minutes. Cysteinyl leukotriene and LTB4 antagonists inhibited the agonist-induced NO production by 70%, and treatment with Bordetella pertussis toxin, or chelation of cytosolic Ca2+, [Ca2+]i, also efficiently inhibited this response. In contrast, treatment of PMN with cytochalasin B (5 microg/mL) enhanced the LTB4-induced NO formation by 86%. Thus, this is the first demonstration that the cysteinyl leukotrienes LTC4 and LTD4, as well as LTB4, activate NO release from human PMN by surface receptor, G-protein and [Ca2+]i-dependent mechanisms. This effect differs from activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, for which only LTB4 is an activator.

Stimulus-dependent transduction mechanisms for nitric oxide release in human polymorphonuclear neutrophil leukocytes.

The production of nitric oxide (NO) may play an important role in functional responses of the human polymorphonuclear neutrophil granulocytes (PMNs). Others have described the presence of both an inducible, Ca2+-independent and a constitutionally expressed, Ca2+-dependent nitric oxide synthase (NOS) in human PMNs. However, the conditions for production and release of NO in human PMNs are still largely unknown. We assessed mechanisms for activation of NO release from human PMNs and particularly the dependence on extracellular and intracellular Ca2+. We addressed this question by applying a variety of agonists with known and differing mechanisms of activation in PMNs and measuring the released NO by two highly sensitive and specific real-time methods for detection of NO, the oxidation of oxyhemoglobin to methemoglobin and an electrochemical method. We found that human PMNs activated with the surface receptor-dependent agonist, N-formyl-methionyl-leucyl-phenylalanine (fMLP); the calcium ionophore, A23187; or the direct stimulator of protein kinase C, phorbol myristate acetate (PMA), produced NO which was inhibited by a specific NOS inhibitor, NG-monomethyl-L-arginine. The NO production induced by fMLP or A23187 was dependent on the presence of extracellular Ca2+, but this was not the case for PMA. The stimulatory effect of fMLP was almost completely inhibited by Bordetella pertussis toxin. These results indicate an NOS activity in purified human PMNs in vitro, and the transduction mechanisms for the agonists used show strong similarity with previously known pathways for other neutrophil functions.

The duration of oral anticoagulant therapy after a second episode of venous thromboembolism. The Duration of Anticoagulation Trial Study Group.

BACKGROUND: A consensus has not been reached about the optimal duration of oral anticoagulant therapy after a second episode of venous thromboembolism. METHODS: In a multicenter trial, we compared six months of oral anticoagulant therapy with anticoagulant therapy continued indefinitely in patients who had had a second episode of venous thromboembolism. Of 227 patients enrolled, 111 were randomly assigned to six months of anticoagulation and 116 were assigned to receive anticoagulant therapy indefinitely; for both groups, the target international normalized ratio was 2.0 to 2.85. The initial episodes of deep-vein thrombosis (n = 193) and pulmonary embolism (n = 34), as well as recurrent episodes, were all objectively confirmed. RESULTS: After four years of follow-up, there were 26 recurrences of venous thromboembolism that fulfilled the diagnostic criteria, 23 in the group assigned to six months of therapy (20.7 percent) and 3 in the group assigned to continuing therapy (2.6 percent). The relative risk of recurrence in the group assigned to six months of therapy, as compared with the group assigned to therapy of indefinite duration, was 8.0 (95 percent confidence interval, 2.5 to 25.9). There were 13 major hemorrhages, 3 in the six-month group, (2.7 percent) and 10 in the infinite-treatment group (8.6 percent). The relative risk of major hemorrhage in the six-month group, as compared with the infinite-treatment group was 0.3 (95 percent confidence interval, 0.1 to 1.1). There was no difference in mortality between the two groups. CONCLUSIONS: Prophylactic oral anticoagulation that was continued for an indefinite period after a second episode of venous thromboembolism was associated with a much lower rate of recurrence during four years of follow-up than treatment for six months. However, there was a trend toward a higher risk of major hemorrhage when anticoagulation was continued indefinitely.

Fludarabine, as well as 2-chlorodeoxyadenosine, can induce eosinophilia during treatment of lymphoid malignancies.

We treated 25 patients suffering from low-grade lymphoid malignancies with nucleoside analogues. In 11 patients undergoing treatment with fludarabine, two patients with follicular lymphoma developed a marked absolute peripheral blood eosinophilia devoid of clinical symptoms which resolved without medical intervention. Of 15 patients treated with 2-chlorodeoxyadenosine, one patient with B-cell chronic lymphocytic leukaemia (CLL) experienced repeated episodes of eosinophilia that required steroid treatment. Eosinophilia in these three patients was not coupled to tumour lysis, and we found no correlation between the occurrence of eosinophilia and clinical response to treatment. Thus, for the first time, we can report eosinophilia as a side-effect of fludarabine treatment, and these are also the first published cases of this complication occurring in patients treated with nucleoside analogues for follicular lymphoma and CLL.

Measurement of methemoglobin formation from oxyhemoglobin. A real-time, continuous assay of nitric oxide release by human polymorphonuclear leukocytes.

We have evaluated the spectrophotometric measurement (at 401 vs. 411 nm) of nitric oxide (NO)-dependent methemoglobin formation from oxyhemoglobin in order to assess NO release from human polymorphonuclear neutrophil leukocytes (PMN). S-nitroso-D,L-acetyl-penicillamine (SNAP, 25-200 microM), a donor of NO, induced a dose-dependent methemoglobin formation. Furthermore, when PMN were activated with N-formyl-methionylleucyl-phenylalanine or phorbol myristate acetate in the presence of superoxide dismutase (SOD) and catalase, methemoglobin formation ensued. The amount of methemoglobin formed was dependent on the amounts of oxyhemoglobin and stimulus used, and the number of PMN in the assay. The NO synthase (NOS) inhibitors NG-monomethyl-L-arginine or nitro-L-arginine methyl ester did not affect methemoglobin generation from oxyhemoglobin induced by SNAP but inhibited that mediated by activated PMN with IC50 values of 250 microM and 340 microM, respectively. The substrate for NO formation from NOS, L-arginine in concentrations up to 1 mM did not significantly influence the methemoglobin formation either induced by SNAP or activated PMN. Exclusion of SOD did not affect SNAP-dependent oxidation of oxyhemoglobin. Exclusion of SOD from the cell-containing system attenuated methemoglobin formation, and if catalase was also excluded the response was further reduced. Finally, PMN from a patient with X-linked chronic granulomatous disease, unable to produce superoxide anions, showed a similar production of methemoglobin from HbO2 as did healthy PMN, activated with the respective agonists. We conclude that spectrophotometric measurement of methemoglobin formation from oxyhemoglobin in the presence of SOD and catalase is a suitable method for the measurement of NO release from PMN, with the benefits of a real-time, continuous assay.

A comparison of six weeks with six months of oral anticoagulant therapy after a first episode of venous thromboembolism. Duration of Anticoagulation Trial Study Group.

BACKGROUND: The optimal duration of oral anticoagulant therapy after a first episode of venous thromboembolism is still a matter of debate. METHODS: We performed a multicenter trial comparing six weeks of oral anticoagulant treatment with six months of such therapy in patients who had a first episode of venous thromboembolism. Anticoagulant therapy consisted of warfarin or dicumarol. Of the 902 patients enrolled, 5 were later excluded because they had congenital protein C deficiency; 443 were randomly assigned to receive six weeks of oral anticoagulant therapy with a targeted international normalized ratio (INR) of 2.0 to 2.85, and 454 were randomly assigned to receive six months of such therapy. The initial diagnoses were confirmed by means of venography in cases of deep-vein thromboses (n = 790) and with perfusion-ventilation scanning or angiography in cases of pulmonary embolism (n = 107); recurrences were confirmed in the same way. RESULTS: After two years of follow-up, there had been 123 recurrences of venous thromboembolism that met the diagnostic criteria, 80 in the six-week group (18.1 percent; 95 percent confidence interval, 14.5 to 21.6) and 43 in the six-month group (9.5 percent; 95 percent confidence interval, 6.8 to 12.2). The odds ratio for recurrence in the six-week group was 2.1 (95 percent confidence interval, 1.4 to 3.1). There was no difference in mortality or the rate of major hemorrhage between the six-week and six-month groups. CONCLUSIONS: Six months of prophylactic oral anticoagulation after a first episode of venous thromboembolism led to a lower recurrence rate than did treatment lasting for six weeks. The difference between the two groups occurred between 6 weeks and 6 months after the start of treatment, and the rates of recurrence remained nearly parallel for 1 1/2 years thereafter.