The risk of a first and a recurrent venous thrombosis associated with an elevated D-dimer level and an elevated thrombin potential: results of the THE-VTE study - van Hylckama Vlieg, A; Baglin, C A; Luddington, R; MacDonald, S; Rosendaal, F R; Baglin, T P (J Thromb Haemost, 2015)