Objective-Hypofibrinolysis promotes atherosclerosis progression and recurrent ischemic events in premature coronary artery disease. We investigated the role of fibrin physical properties in this particular setting. Methods and Results-Biomarkers of recurrent thrombosis and premature coronary artery disease (CAD) were measured in 33 young post-myocardial infarction patients with angiographic-proven CAD and in 33 healthy volunteers matched for age and sex. Ex vivo plasma fibrin physical properties were assessed by measuring fibrin rigidity and fibrin morphological properties using a torsion pendulum and optical confocal microscopy. The fibrinolysis rate was derived from continuous monitoring of the viscoelastic properties after addition of lytic enzymes. Young CAD patients had a significant increase in plasma concentration of fibrinogen, von Willebrand factor, plasminogen activator inhibitor type 1, and lipoprotein(a) as compared with controls (PϽ0.05). Fibrin of young CAD patients was stiffer (Pϭ0.002), made of numerous (Pϭ0.002) and shorter fibers (Pϭ0.04), and lysed at a slower rate than that of controls (Pϭ0.03). Fibrin stiffness was an independent predictor for both premature CAD and hypofibrinolysis. Conclusions-This first detailed study of clot properties in such a group of patients demonstrated that abnormal plasma fibrin architecture is an important feature of both premature CAD and fibrinolysis rate. Key Words: acute coronary syndromes Ⅲ coagulation Ⅲ fibrinolysis Ⅲ pathophysiology Ⅲ fibrinogen Ⅲ thrombophilia T he mechanical properties of clots and their major constituent fibrin are normally finely tuned to optimize bleeding control while also minimizing their effect on atherothrombosis. 1,2 A decreased rate of fibrinolysis and increased thrombosis are generally associated with stiff clots, although such relationships are complex. 3,4 Many factors that affect clot structure have a great impact on the mechanical properties fibrin and fibrinolysis through modifications of various steps in the fibrin polymerization process and clot stabilization. 1,4,5 See page 2419Premature coronary artery disease (CAD) is associated with increased plasma levels of prothrombotic and proinflammatory biomarkers, including fibrinogen and plasminogen activator inhibitor (PAI) type 1, which are known to favor hypofibrinolysis 6 and to be independent predictors of CAD. 7,8 Epidemiological studies have also revealed a relationship between myocardial infarction (MI) and reduced permeability and increased stiffness of fibrin, especially in young post-MI patients. 9 These aspects of altered fibrin clot network architecture were not found to be attributable to classic risk factors including fibrinogen concentrations or common polymorphisms. 2 However, the relationships among premature CAD, abnormal fibrin physical properties, and hypofibrinolysis remain little explored. The lack of appropriately designed studies of the physical properties of fibrin, including simultaneous determination of viscoelastic and morphological properties o...
Background-The pathogenesis of unstable angina and non-Q-wave myocardial infarction is still poorly understood, and early evaluation of prognosis remains difficult. We therefore studied the predictive value of 5 biological indicators of inflammation, thrombogenesis, vasoconstriction, and myocardial necrosis, and we examined the effects of enoxaparin and unfractionated heparin on these markers after 48 hours of treatment. Methods and Results-Sixty-eight patients with unstable angina or non-Q-wave myocardial infarction randomized in the international ESSENCE trial participated in this French substudy. C-reactive protein, fibrinogen, von Willebrand factor antigen, endothelin-1 and troponin I were measured on admission and 48 hours later. The composite end point of death, myocardial infarction, recurrent angina, or revascularization was significantly lower at 14 and 30 days of follow-up in patients allocated to enoxaparin compared with unfractionated heparin. All acute-phase reactant proteins were elevated on admission and increased further at 48 hours. Multivariate analysis demonstrated that the rise of von Willebrand factor over 48 hours was a significant and independent predictor of the composite end point at both 14 days and 30 days. Moreover the early increase of von Willebrand factor was more frequent and more severe with unfractionated heparin than with enoxaparin (mean change was ϩ8.7Ϯ8.8% with enoxaparin versus ϩ93.9Ϯ11.7% with unfractionated heparin, PϽ0.0001). The other clinical and biological variables did not predict outcome. Conclusions-In patients with unstable angina or non-Q-wave myocardial infarction, the acute-phase proteins increase over the first 2 days despite medical treatment. The early rise of von Willebrand factor is an independent predictor of adverse clinical outcome at 14 days and at 30 days. Enoxaparin provides protection as evidenced by the reduced release of von Willebrand factor, which represents a favorable prognostic finding. (Circulation. 1998;98:294-299.)
Background-A few studies have suggested that von Willebrand factor (vWF) or plasminogen activator inhibitor-1 (PAI-1) can be associated with outcomes of acute coronary syndromes. The present study was designed to assess the acute release of these markers in ST-segment elevation myocardial infarction (STEMI) and their relations to death. Methods and Results-In 153 consecutive patients with STEMI, vWF and PAI-1 antigens were measured on admission (H0) and 24 hours later (H24). At 30 days, the death rate was 7.2%. Heart failure (Killip stage Ն3) on admission was present in 13.7% of patients. The acute release of PAI-1 (H24ϪH0, in ng/mL) and of vWF (H24ϪH0, in %) was dramatically higher in patients who died than in those who survived (46.9Ϯ26.3 versus Ϫ0.6Ϯ2.8 ng/mL, Pϭ0.0001 and 65.8Ϯ20.0% versus 10.0Ϯ5.1%, Pϭ0.004 for PAI-1 and vWF, respectively) and in patients developing heart failure compared with those without (24.8Ϯ10.1 versus Ϫ1.1Ϯ3.3 ng/mL, Pϭ0.004 and 47.3Ϯ11.0% versus 8.1Ϯ5.6%, Pϭ0.005 for PAI-1 and vWF, respectively). The release of PAI-1 correlated weakly with the left ventricular ejection fraction (RϭϪ0.195, Pϭ0.01) and the peak of troponin (Rϭ0.149, Pϭ0.045). Postangioplasty TIMI-3 flow and the acute release of PAI-1 were the only 2 independent predictors of death at 30 days. Conclusions-The acute release of vWF and PAI-1 over the first 24 hours of STEMI is associated with death and heart failure. The acute rise of PAI-1 is also a strong independent predictor of death at 30 days.
T(4) levels are determinant of several components of the fibrinolytic system. However, relationships between hypothyroidism and alteration of fibrinolytic capacity are not well established, and published data remain conflicting. As the impact of hypothyroidism on both degradation and synthesis of proteins may vary according to the severity of the disease, we measured fibrinolytic activity across varying states of hypothyroidism. We measured fibrinogen, D-dimers (DDI), alpha(2)-antiplasmin activity, tissue plasminogen activator antigen (t-PA Ag), plasminogen, plasminogen activator inhibitor antigen (PAI-1 Ag), and factor XII (FXII) of the coagulation. We prospectively included 76 middle-aged female subjects: 25 controls, 24 patients displaying moderate hypothyroidism (TSH, 10--50 mU/L), and 27 patients with severe hypothyroidism (TSH, >50 mU/L). Blood pressure, body mass index, smoking habits, total cholesterol as well as high and low density lipoprotein subfractions, triglyceride, fasting glycemia, and insulinemia were recorded. We found a different pattern of fibrinolytic abnormalities according to the severity of hypothyroidism. Compared with controls, patients with moderate hypothyroidism displayed a decreased fibrinolytic activity, as reflected by lower DDI levels, higher alpha(2)-antiplasmin activities, and higher levels of t-PA and PAI-1 Ag. In sharp contrast, patients with severe hypothyroidism exhibited higher DDI levels, lower alpha(2)-antiplasmin activities, and lower t-PA and PAI-1 Ag levels. These results were not accounted for by confounding factors such as age, smoking, and components of the insulin resistance syndrome. Free T(4) was significantly associated with fibrinogen, alpha(2)-antiplasmin, PAI-1 Ag, total cholesterol, and triglyceride and was negatively associated with DDI. The main hypotheses underlying the mechanisms by which thyroid status may affect the fibrinolytic system remain to be established. In conclusion, patients with moderate hypothyroidism, who were consistently shown to be at high risk for cardiovascular disease, have decreased fibrinolytic activity. Subjects with severe hypothyroidism have a tendency toward increased fibrinolytic activity, and these modifications may participate to the bleeding tendency observed in such patients.
BackgroundLess than 50 patients with FPD/AML (OMIM 601309) have been reported as of today and there may an underestimation. The purpose of this study was to describe the natural history, the haematological features and the genotype-phenotype correlations of this entity in order to, first, screen it better and earlier, before leukaemia occurrence and secondly to optimize appropriate monitoring and treatment, in particular when familial stem cell transplantation is considered.MethodsWe have investigated 41 carriers of RUNX1 alteration belonging to nine unrelated French families with FPD/AML and two syndromic patients, registered in the French network on rare platelet disorders from 2005 to 2015.ResultsFive missense, one non-sense, three frameshift mutations and two large deletions involving several genes including RUNX1 were evidenced. The history of familial leukaemia was suggestive of FPD/AML in seven pedigrees, whereas an autosomal dominant pattern of lifelong thrombocytopenia was the clinical presentation of two. Additional syndromic features characterized two large sporadic deletions. Bleeding tendency was mild and thrombocytopenia moderate (>50 x109/L), with normal platelet volume. A functional platelet defect consistent with a δ-granule release defect was found in ten patients regardless of the type of RUNX1 alteration. The incidence of haematological malignancies was higher when the mutated RUNX1 allele was likely to cause a dominant negative effect (19/34) in comparison with loss of function alleles (3/9). A normal platelet count does not rule out the diagnosis of FPD/AML, since the platelet count was found normal for three mutated subjects, a feature that has a direct impact in the search for a related donor in case of allogeneic haematopoietic stem cell transplantation.ConclusionsPlatelet dysfunction suggestive of defective δ-granule release could be of values for the diagnosis of FPD/AML particularly when the clinical presentation is an autosomal dominant thrombocytopenia with normal platelet size in the absence of familial malignancies. The genotype-phenotype correlations might be helpful in genetic counselling and appropriate optimal therapeutic management.
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