Abstract 13625: Laboratory Markers of Effective Endogenous Fibrinolysis in Intermediate-High-Risk Pulmonary Embolism

Abstract

Introduction: Unselected therapy with fibrinolysis in intermediate risk-pulmonary embolism (iPE) is associated with an unacceptable risk of bleeding. Early identification of iPE patients on anticoagulant therapy with ineffective endogenous fibrinolysis (eFL) could optimize treatment-strategy. Aims: The study aims to determine markers of (in)effective eFL in intermediate-risk PE initially on anticoagulant therapy with UFH. Methods: In course of 24 months, iPE patients were enrolled in the prospective study. At admission, and every 24 hours until day 5, levels of 6 selected markers of eFL (i.e., PAI-1 and tPA active assay and total antigen, TAFI, and PAP) were determined. Upon arrival and following a span of 36 hours,defined i) Clinical (heart rate >100 bpm and spontaneous oxygen saturation <90%), ii) Echo (D-shape, RVd/LVd from PLAX>0.7, RV/RA >30mmHg), and iii) CT (RV/LV>0.9) variables were obtained. An (un)successful therapy was assessed by one point for each clinical, Echo and CT criteria, as at least one parameter from initially altered has adjusted at 36 hours. We performed correlation of laboratory markers with the dynamics of clinical and imaging characteristics. Results: Study population consists of 44 patients, 22 men, mean (SD) age 60 (18.3) yr., first (38), repeat (6) PE. Plasminogen activator inhibitor-1 (PAI-1) active assay showed the most promising results. The cut-off for unsuccessful therapy from AUC for PAI-1 was ≥65 U/ml. Mean (IQR) levels of PAI-1 on day 1 were 119 U/ml (27.1 - 155.8) and were significantly higher on day 1 (p=0.019) and day 2 (p=0.055) in those with/without adjustment of initial pathological findings. PAI-1 elevation was associated with unsuccessful restoration of clinical, Echo and CT parameters at 36 hours (Table1). Overall Tx failure was associated with elevated PAI-1 (p=0.011). Conclusions: PAI-1 active assay could help us in identifying patients who would benefit from early indicated therapeutic fibrinolysis.