Coagulation activation-induced fibrinolysis biomarker changes depend on thrombophilic risk factors and their clinical phenotype: an interventional in vivo study

Background: Recently we have shown alterations in the anticoagulant response to recombinant activated factor VII (rFVIIa)-induced coagulation activation in patients with thrombophilia. Objectives: Here we extended this in vivo model to study fibrinolysis biomarkers. Methods: The study population included 56 patients with thrombophilia and a history of venous thromboembolism (VTE+), 38 asymptomatic patients with thrombophilia (VTE-) and 35 healthy controls. Plasma levels of D-dimer, plasmin-α2-antiplasmin complex (PAP), and plasminogen activator inhibitor-1 (PAI-1) were monitored over 8 hours after rFVIIa infusion (0.015 mg/kg) along with thrombin activation markers and activated protein C (APC). Results: In all cohorts, PAP increased (P<3.9∙10-10) and PAI-1 decreased (P<3.5∙10-8). In contrast to thrombin-antithrombin complex (TAT), which also increased temporarily in all cohorts (P<3.6∙10-6), changes of PAP and PAI-1 did not reverse during the observation period. The area under the curve (AUC) of PAP (respectively TAT), as measure of plasmin (respectively thrombin) formation, was greater in the VTE+ cohort than in healthy controls (PAP AUC P=0.003, TAT AUC P=2.5∙10-4) and showed correlation (r=0.554). As evidenced by the respective AUCs, asymptomatic factor V Leiden (FVL) carriers in the VTE- cohort showed less PAP formation (P=9∙10-4), more pronounced PAI-1 decline (P=0.010), and increased APC formation (P=0.020) than those within the VTE+ group (n=19 each). This was not observed in prothrombin 20210G>A carriers or patients with unexplained familial thrombophilia. Conclusion: rFVIIa-induced thrombin formation is associated with fibrinolysis parameter changes outlasting the concomitant anticoagulant response. Both correlate with thrombosis history in FVL and might help to explain its variable clinical expressivity. ### Competing Interest Statement B.P. and J.M. have a patent DE102007063902B3 including the aptamer HS02-52G binding to APC. An assay for the quantification of APC levels in human plasma, based on this aptamer, has been licensed to ImmBioMed, Pfungstadt, Germany. B.P. and J.M. have a patent DE102007041476 including the aptamer HD1-22 binding to thrombin. An assay for the quantification of thrombin levels in human plasma, based on this aptamer, has been licensed to ImmBioMed, Pfungstadt, Germany. J.O. has received research funding from Bayer, Biotest, CSL Behring, Octapharma, Pfizer, Swedish Orphan Biovitrum, and Takeda; consultancy, speakers bureau, honoraria, scientific advisory board, and travel expenses from Bayer, Biogen Idec, BioMarin, Biotest, Chugai Pharmaceutical Co., Ltd., CSL Behring, Freeline, Grifols, LFB, Novo Nordisk, Octapharma, Pfizer, F. Hoffmann-La Roche Ltd., Sanofi, Spark Therapeutics, Swedish Orphan Biovitrum, and Takeda. The other authors declare no competing financial interests.