Extracorporeal membrane oxygenation to resuscitate a 14-year-old boy after 43min drowning / Oxigenación de la membrana extracorpórea para resucitar a un niño de 14 años después de 43 minutos de ahogamiento

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Variability of cut-off values for the detection of lupus anticoagulants: results of an international multicenter multiplatform study.

Essentials Between-lab variations of cut-off values in lupus anticoagulant detection are unknown. Cut-off values were calculated in 11 labs each testing plasma from 120 donors with 3 platforms. Major variation was observed even within the same platform. Cut-off values determined in different labs are not interchangeable. SUMMARY: Background Cut-off values for interpretation of lupus anticoagulant (LA) detection are poorly investigated. Aims (i) To assess whether results from healthy donors were normally distributed and (ii) the between-laboratories differences in cut-off values for screening, mixing and LA confirmation when calculated as 99th or 95th centiles, and (iii) to assess their impact on the detection rate for LA. Methods Each of 11 laboratories using one of the three widely used commercial platforms for LA detection was asked to collect plasmas from 120 healthy donors and to perform screening, mixing and LA confirmation with two methods (activated partial thromboplastin time [APTT] and dilute Russell viper venom [dRVV]). A common set of LA-positive or LA-negative freeze-dried plasmas was used to assess the LA detection rate. Results were centralized (Milano) for statistical analysis. Results and conclusions (i) Clotting times or ratios for healthy subjects were not normally distributed in the majority of cases. The take-home message is that cut-off values should be determined preferably by the non-parametric method based on centiles. (ii) There were relatively large inter-laboratory cut-off variations even within the same platform and the variability was marginally attenuated when results were expressed as ratios (test-to-normal pooled plasma). The take-home message is that cut-off values should be determined locally. (iii) There were differences between cut-off values calculated as 99th or 95th centiles that translate into a different LA detection rate (the lower the centile the greater the detection rate). The take-home message is that cut-off values determined as the 95th centile allow a better LA detection rate.

Factor V leiden increases plasma F1+2 levels both in normal and deep venous thrombosis subjects.

BACKGROUND AND OBJECTIVE: A simple approach to understanding molecular mechanisms leading to thrombosis is the definition of how genetic factors influence biochemical parameters of coagulation. Conflicting data have been reported regarding the role that the genotype of factor V plays in the control of plasma F1+2 levels. The aim of this study was to test whether the factor V Leiden mutation affects F1+2 levels. DESIGN AND METHODS: We studied the effect of factor V Leiden mutation (detected by the polymerase chain reaction technique) on plasma F1+2 levels in 418 normal subjects and 39 subjects affected by deep venous thrombosis. RESULTS: In both normal subjects and those with venous thrombosis, heterozygotes for the Leiden mutation showed significantly higher plasma levels of F1+2 (p<0.0001 and p<0.005, respectively). Subjects with venous thrombosis had a higher allelic frequency of the Leiden mutation than normal subjects (11.5% and 3.1%, respectively). INTERPRETATION AND CONCLUSIONS: The results indicate that the genotype of factor V is a determinant of plasma F1+2 concentration. The allelic frequency of Leiden mutation in our normal subjects is higher than that found in other Italian populations but similar to that reported for populations of north- and middle-Europe. This finding is consistent with the peculiar ancestry and history of Friuli (the area in which subjects for this study were recruited), with respect to other Italian regions.

Effect of intensive glycaemic control on fibrinogen plasma concentrations in patients with Type II diabetes mellitus. Relation with beta-fibrinogen genotype.

Recent studies show that in diabetic subjects an increase of plasma fibrinogen concentration is associated with a high risk of cardiovascular complications. Environmental and genetic factors contribute to the plasma fibrinogen concentration. Several studies indicate a relation between the polymorphism in the 5' region of the beta-fibrinogen gene and plasma protein concentrations and in diabetes the possible influence of hyperglycaemia on fibrinogen is still debated. In this study we investigated these relations. Hind III polymorphism was evaluated by a polymerase chain reaction-technique. On the basis of the observed allelic combination of fibrinogen beta-gene polymorphism and the existence of poor metabolic control (glycated haemoglobin > or = 7.5%), 50 Type II diabetic patients were selected. They were divided into three groups according to their beta-gene polymorphism (alpha1alpha1: n = 20, alpha1alpha2: n = 15, alpha2alpha2: n = 15) and then intensive insulin therapy was started. After 3 months of intensive treatment, the improvement in glycaemic control was equivalent, in terms of glycated haemoglobin, in all the three groups. A fibrinogen reduction was observed in alpha1alpha2 and alpha2alpha2 but not in alpha1alpha1 subjects. These results underline a possible relation between fibrinogen genotypes and glycaemic control in determining plasma fibrinogen concentrations in diabetic patients.

Total plasma antioxidant capacity predicts thrombosis-prone status in NIDDM patients.

OBJECTIVE: To explore the hypothesis that a relationship exists between free radical activity and abnormalities in hemostasis in NIDDM. RESEARCH DESIGN AND METHODS: The use of the total radical-trapping antioxidant parameter (TRAP) has very recently been proposed to explore the antioxidant property of a plasma and their mutual cooperation. In the present study, TRAP, vitamin E, vitamin C, vitamin A, uric acid, protein-bound SH (thiol) groups, fibrinogen, prothrombin fragments F1 + 2, and D-dimer have been evaluated in 46 NIDDM patients and 47 healthy matched control subjects. RESULTS: In NIDDM patients, TRAP, vitamin A, SH groups, and uric acid were significantly reduced, whereas the level of vitamin E was significantly increased. Vitamin C was similar in the two groups. Fibrinogen, prothrombin fragment 1 + 2, and D-dimer were increased in diabetic patients. TRAP, but no single other antioxidant, had a strong inverse association with fibrinogen, prothrombin fragment 1 + 2, and D-dimer. CONCLUSIONS: These findings are consistent with the hypothesis that oxidative stress may condition coagulation activation in diabetics. However, the data suggest that it is the total antioxidant capacity rather than any single plasma antioxidant that is the most relevant parameter.

Long-term effects of erythropoietin therapy on fistula stenosis and plasma concentrations of PDGF and MCP-1 in hemodialysis patients.

Among the adverse effects possibly associated with the use of erythropoietin (EPO) in hemodialysis patients is an increased incidence of thrombosis of the vascular access. However, little is known about the effect of EPO on the stenotic lesion in the venous outflow system, which is the leading cause of fistula thrombosis. This study was designed to explore the long-term effects of EPO treatment on progressive fistula stenosis and the plasma concentrations of some potential mediators of neointimal hyperplasia. A cross-sectional and 3-yr prospective, placebo-controlled, pilot study was performed in 30 hemodialysis patients with native arteriovenous fistula. Sixteen patients received EPO and 14 received a placebo. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Compared with 60 healthy subjects, the hemodialysis patients had elevated plasma levels of platelet-derived growth factor, monocyte chemoattractant protein-1, and interleukin 6, three proteins that might be involved in the neointima formation regulating the proliferation of vascular smooth muscle cells. In addition, these patients had numerous endothelial and hemostatic abnormalities that indicated a thrombophilic state. Eleven patients, six (37.5%) receiving EPO and five (35.7%) taking placebo, developed a progressive stenosis in the venous circuit of the fistula. There was no significant difference in the vascular access, event-free survival over 36 mo between patients receiving EPO therapy and placebo. EPO induced a significant decrease in the plasma values of platelet-derived growth factor and vascular cell adhesion molecule-1 and an increase of monocyte chemoattractant protein-1 concentration. After EPO withdrawal, these parameters returned to pretreatment levels. In conclusion, long-term EPO therapy does not increase the risk of progressive stenosis of native arteriovenous fistula. The use of erythropoietin does not induce any prothrombotic change in hemostatic parameters, and further studies are required to elucidate the theoretically beneficial effects on the plasma concentration of some potential mediators of neointimal formation.

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients.

Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.

Post-meal coagulation activation in diabetes mellitus: the effect of acarbose.

It has been previously demonstrated that hyperglycaemia activates haemostasis; diabetes mellitus is considered a thrombosis-prone state. Acarbose, by inhibiting dietary carbohydrate absorption, reduces post-meal hyperglycaemia. In this study we evaluated the effect of post-meal hyperglycaemia on two markers of coagulation activation: prothrombin fragments 1 + 2 and D-dimer. Seventeen non-insulin-dependent diabetic patients maintained on diet therapy alone were randomly assigned to receive- with a cross-over study design-acarbose (100 mg orally) or placebo before a standard meal. Blood samples for measurement of plasma glucose, insulin, prothrombin fragments 1 + 2 and D-dimer were drawn at 0, 60, 120 and 240 min. After both placebo and acarbose, hyperglycaemia and hyperinsulinaemia which followed a standard meal were accompanied by a significant increase of plasma concentration of prothrombin fragments 1 + 2 and D-dimer in comparison to their baseline values. Acarbose administration significantly reduced the rise of glucose, insulin, prothrombin fragments 1 + 2 and D-dimer from 0 to 240 min in comparison to placebo. We conclude that post-meal hyperglycaemia, at the level reached by many diabetic patients on diet therapy alone, induces a coagulation activation. Acarbose, by decreasing post-meal hyperglycaemia, may be useful in reducing meal-induced activation of haemostasis in diabetic patients.

Hyperglycemia-induced thrombin formation in diabetes. The possible role of oxidative stress.

Diabetes is characterized by the existence of a thrombosis-prone condition, possibly related to hyperglycemia. However, the mechanism linking hyperglycemia to the activation of the coagulation cascade is still unclear. It has been recently suggested that diabetes is accompanied by increased oxidative stress. In this work, the possibility that oxidative stress may be involved in the hyperglycemia-induced coagulation activation has been evaluated. Prothrombin fragment 1 + 2 (F1 + 2), which represents a reliable marker of the amount of thrombin released in the circulation, has been chosen for studying thrombin formation in vivo. In nine type II diabetic patients and in seven healthy control subjects, matched for age and body mass index, three different experiments were performed: oral glucose tolerance test (OGTT), intravenous antioxidant glutathione (GSH) administration for 2 h, and OGTT plus intravenous GSH administration. Samples were drawn at -15 min and every 30 min from 0 to 180 min. During the OGTT, F1 + 2 significantly increased in both diabetic and healthy subjects. GSH administration during OGTT normalized this phenomenon. GSH administration alone significantly decreased F1 + 2 in diabetic patients, while no effect was observed in the normal subjects. These data suggest that hyperglycemia may induce thrombin activation, possibly inducing an oxidative stress, and that antioxidant GSH may counterbalance this effect.

Deficient antithrombin III activity and enhanced fibrinolysis in patients with liver disease: evidence against a cause-effect relationship.

To investigate the pathogenesis of fibrinolysis in liver disease, antithrombin III (AT III) activity, prothrombin fragment (F1 + 2) and d-dimer (D-DI) were measured in 50 patients with liver disease and in 17 healthy controls. Moreover, 4 patients with cirrhosis were randomly assigned to receive either an intravenous infusion of AT III (at two different dosages) or placebo, with a crossover design. Increased levels of D-DI were detected in patients with cirrhosis and hepatocellular carcinoma in comparison both with control subjects and with patients with acute hepatitis or mild chronic liver disease. An inverse correlation was observed between AT III and D-DI (r = -0.755, P < 0.001, simple linear regression), while no correlation was found between D-DI or AT III and F1 + 2. The correlation of the deficiency of AT III activity by infusion of human AT III did not result in any significant change (P0.10, analysis of variance for repeated measures) of the plasma concentration of either D-DI or F1 + 2, in comparison to placebo. Thus, advanced forms of chronic liver disease, but not acute hepatitis and mild forms of chronic liver disease, are associated with increased plasma concentrations of markers of fibrinolysis, which are inversely correlated with AT III activity. However, the correction of the deficient AT III activity does not affect the plasma concentration of either D-DI or F1 + 2, thence not supporting the hypothesis that enhanced fibrinolysis in advanced liver disease is the result of low-grade disseminated intravascular coagulation.

Fibrinogen plasma levels as a marker of thrombin activation: new insights on the role of fibrinogen as a cardiovascular risk factor.

Fibrinogen has recently emerged as a major risk factor for atherothrombosis. However, the pathophysiologic mechanism linking high fibrinogen concentration to cardiovascular disease is unclear. In this study 136 subjects (75 males, 61 females, age 51.7 +/- 14.4 years, mean +/- standard deviation, range 17-82) were tested for total and HDL-cholesterol, total triglycerides, apolipoprotein AI, apolipoprotein B, fibrinogen, prothrombin fragment and D-dimer. Moreover, 5 subjects who had hyperfibrinogenemia (range 450 to 950 mg/dl) for at least 6 months by repeated measurements, were treated with a short 7-day course of heparin 12,500 U/day subcutaneously. The effect of heparin on all the above mentioned parameters was observed at the end of treatment and after 7 days of wash-out. Simple regression analysis detected a positive correlation between fibrinogen and age, prothrombin fragment and D-dimer, and a negative correlation between fibrinogen and HDL-cholesterol and apolipoprotein AI. A direct correlation between age and both prothrombin fragment and D-dimer was also demonstrated. Multivariate analysis showed a persistent correlation between fibrinogen and prothrombin fragment, D-dimer and age, that was not influenced by sex, smoking habit and body mass index. In the 5 hyperfibrinogenemic subjects, heparin administration significantly reduced fibrinogen (625.4 +/- 211.1 vs 455.2 +/- 112.3 mg/dl, p < 0.03), prothrombin fragment (0.97 +/- 0.1 vs 0.63 +/- 0.2 nM, p < 0.002) and D-dimer (336 +/- 101.8 vs 275.2 +/- 78.5 ng/ml, p < 0.03). All these parameters returned to baseline after 7 days of wash-out (fibrinogen 632.5 +/- 198.2 mg/dl, prothrombin fragment 0.96 +/- 0.2 nM, D-dimer 325.8 +/- 98.65 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrinogen plasma levels as a marker of thrombin activation in diabetes.

This study attempted to verify the existence of a correlation between fibrinogen, a major cardiovascular risk factor in diabetes, and indexes of thrombin generation and action, prothrombin fragment 1 + 2 (F1 + 2), and D-dimer (D-D), in a group of diabetic subjects compared with a matched control group. Forty insulin-dependent diabetes mellitus patients and 30 matched healthy control subjects participated in this study. The subjects were tested for the following parameters: fibrinogen, prothrombin F1 + 2, D-D, fasting glycemia, and HbA1c. In addition, 5 diabetic subjects who maintained stable fibrinogen plasma levels > 300 mg/dl for at least 6 months before the study were treated with 12,500 U/day subcutaneous heparin for 7 days. Diabetic subjects showed increased levels of fibrinogen, prothrombin F1 + 2, and D-D plasma levels. Simple linear regression analysis detected a positive correlation between fibrinogen and prothrombin F1 + 2, D-D, and glycosylated HbA1c. In the five diabetic subjects treated with heparin fibrinogen, prothrombin F1 + 2 and D-D levels decreased at the end of the treatment. All these parameters returned to baseline after 7 days of washout. These data indicate that fibrinogen plasma levels are correlated to parameters of thrombin activation in plasma in diabetic patients and suggest that high fibrinogen plasma levels might be a risk marker for cardiovascular disease in diabetes because it is an expression of an existing thrombophilia.