Arterial and venous thrombosis and prothrombotic fibrin clot phenotype in a Polish family with type 1 antithrombin deficiency (antithrombin Krakow)

Determinants of plasma fibrin clot lysis measured using three different assays in healthy subjects

INTRODUCTION

Several methods for measuring fibrinolytic capacity in plasma have been developed yielding frequently inconsistent results. We investigated which factors determine fibrinolytic capacity in three plasma-based assays.

MATERIAL AND METHODS

In 80 apparently healthy controls (aged 43 ± 10 years, 50 women [62.5%]) we evaluated fibrinolysis using three assays: (1) by Pieters et al. (CLT2018), (2) by Lisman et al. (CLT), and (3) by Carter et al. (Lys50). Coagulation factors and fibrinolytic proteins, including histidine-rich glycoprotein (HRG) and γ'-fibrinogen, were determined. Regression models were performed to identify determinants of lysis times.

RESULTS

Positive correlations were observed between CLT2018 and both CLT (r = 0.73) and Lys50 (r = 0.61), as well as between CLT and Lys50 (r = 0.46, all p < 0.001). The main determinants of both CLT2018 and CLT were plasminogen activator inhibitor-1 (PAI-1), followed by thrombin-activatable fibrinolysis inhibitor (TAFI) and α₂-antiplasmin. Histidine-rich glycoprotein was a predictor of the longest-normal CLT2018 alone (OR 1.04, 95% CI 1.02-1.06). α₂-Antiplasmin and fibrinogen levels, followed by PAI-1 and TAFI determined Lys50. After adjustment for age, sex, and body mass index, C-reactive protein (CRP) was an independent predictor of the top quartiles of the three lysis times.

CONCLUSIONS

We showed that apart from PAI-1, TAFI, and α₂-antiplasmin, several other factors, in particular CRP, can affect the results of global fibrinolysis tests used in research. Our findings may help understand why the choice of a specific fibrinolysis assay can affect the presence and/or magnitude of intergroup differences in fibrinolytic capacity in a given disease state.

Fibrin clot properties and their modulation in thrombotic disorders

Accumulating evidence indicates that accelerated formation of fibrin clots composed of compact, highly-branched networks with thin fibres which are relatively resistant to plasmin-mediated lysis can be commonly observed in patients with venous or arterial thrombosis. This review discusses characteristics of fibrin clot structure and function in patients with various thromboembolic manifestations, in particular myocardial infarction, ischaemic stroke and venous thromboembolism, based on the publications till December 2013. Moreover, factors will be presented that in vivo unfavourably determine altered fibrin clot properties in thrombotic disorders and modalities that can improve clot phenotype.

Prothrombotic Fibrin Clot Phenotype in Patients with Deep Vein Thrombosis and Pulmonary Embolism: A New Risk Factor for Recurrence

Prothrombotic fibrin clot phenotype, involving faster formation of dense meshwork composed of thinner and highly branched fibers that are relatively resistant to plasmin-induced lysis, has been reported in patients with not only myocardial infarction or stroke, but also venous thromboembolism (VTE), encompassing deep vein thrombosis (DVT), and/or pulmonary embolism (PE). Prothrombotic fibrin clot phenotype, in particular prolonged clot lysis time, is considered a novel risk factor for VTE as well as venous thrombosis at unusual location, for example, cerebral sinus venous thrombosis, retinal vein obstruction, and Budd-Chiari syndrome. Growing evidence from observational studies indicates that abnormal fibrin clot properties can predict recurrent DVT and PE and they are involved in serious complications of VTE, for example, thromboembolic pulmonary hypertension and postthrombotic syndrome. The purpose of this article is to review our current understanding of the role of fibrin clot structure and function in venous thrombosis with emphasis on clinical issues ranging from prognosis to therapy.

Recurrent ischemic cerebrovascular events in a patient with type I antithrombin deficiency caused by 9788 G>A splice site mutation: a case report

Type I antithrombin deficiency is an autosomal dominant disorder associated with high risk for venous thromboembolism. Data on the association between antithrombin deficiency and arterial thromboembolism are inconsistent. We report here the case of AT deficiency in a 43-year-old man free of cardiovascular risk factors who experienced venous thromboembolism and ischemic stroke followed by two transient ischemic attacks after interruption of oral anticoagulation due to colonoscopy. DNA sequencing of the antithrombin gene revealed heterozygosity for the previously reported substitution G to A at nucleotide position 9788 in intervening sequence four. To our knowledge, this report is the first to show that this genetic abnormality can be associated with recurrent cerebrovascular ischemic events.