Imputation of systematically missing predictors in an individual participant data meta-analysis: A generalized approach using MICE

Individual participant data meta-analyses (IPD-MA) are increasingly used for developing and validating multivariable (diagnostic or prognostic) risk prediction models. Unfortunately, some predictors or even outcomes may not have been measured in each study and are thus systematically missing in some individual studies of the IPD-MA. As a...

Patients with deep venous thrombosis and thrombophilia risk factors have a specific prolongation of the lag time in a chromogenic thrombin generation assay

The objective of the present study was to evaluate the influence of thrombophilia risk factors on variables of a chromogenic thrombin generation assay (ETP) in a setting with acute deep venous thrombosis (DVT) and non-DVT patients. In 152 outpatients suspected for DVT, the results of thrombophilia investigations were known. In all patients,...

A thrombin generation assay may reduce the need for compression ultrasonography for the exclusion of deep venous thrombosis in the elderly

Introduction. The exclusion of deep venous thrombosis (DVT) by pre-test probability (PTP) and D-dimer in the elderly is safe, but has a low specificity. There is increasing interest in the diagnostic role of thrombin generation in patients with thrombosis. We evaluated the value of thrombin generation in the exclusion of DVT, especially in...

Deep-vein thrombosis is not associated with the P/S186 polymorphism of histidine-rich glycoprotein

Background: In several studies, higher plasma levels of histidine-rich glycoprotein (HRG) have been observed in patients with venous thrombosis than in healthy subjects. Apart from environmental factors, such as the use of oral contraceptives, the plasma HRG levels are mainly determined genetically. The most important genetic determinant is P...

Exclusion and diagnosis of deep vein thrombosis by a rapid ELISA D- dimer test, compression ultrasonography, and a simple clinical model

The classical clinical signs of deep vein thrombosis (DVT) are unspecific and may be found in several other conditions besides DVT. Therefore, patients suspicious of DVT are subjected to elaborate invasive or noninvasive evidence-based procedures that actually confirm DVT in only 20% to 30% of patients in this setting. However, simple laboratory...

Inhibition of mannose receptor-mediated-clearance of tissue-type plasminogen activator (t-PA) by dextran: A new explanation for its antithrombotic effect

Dextran is used during surgery as a prophylactic agent to prevent deep venous thrombosis. Recently it has been shown that dextran increases t-PA plasma concentrations in patients. As dextran is a potential ligand for the mannose receptor, we studied whether this glucose-polymer would be able to inhibit mannose receptor-mediated clearance of t-PA...

Elevated plasminogen activator inhibitor (PAI), a cause of thrombophilia? A study in 203 patients with familial or sporadic venous thrombophilia

Two hundred and three patients with venous thrombophilia were investigated in order to find out whether an elevated plasma concentration of plasminogen activator inhibitor (PAI) could be a cause of their tendency to thrombosis. The patients were studied in an asymptomatic period about 3 months after their last thromboembolic episode. PAI...