Evaluation of Fibrinogen Levels during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

Purpose: To evaluate the effect of catheter-directed thrombolysis (CDT) with tissue plasminogen activator (tPA) on plasma fibrinogen levels (PFLs) in the setting of acute pulmonary embolism (PE) and the relationship between PFL and hemorrhagic complications. Materials and Methods: A retrospective review of CDT procedures between 2009 and 2019 identified 147 CDT procedures for massive or submassive PE (55.8% males; age, 56.5 +/- 14.8 years; 90.5% submassive). All patients received therapeutic anticoagulation during CDT with unfractionated heparin (UFH) (69.4%) or low-molecular-weight heparin (LMWH. 30.6%) infusion. CDT was performed with ultrasound-accelerated thrombolysis (USAT) catheters (n = 98), conventional catheter-directed thromholysis (C('DT) catheters (n = 34), or a combination of both (n = 15). Results: There was a decrease (P = .007) of 15.1 +/- 69.4 mg/dl from the initial PFL (376.1 +/- 122.7 mg/dl) to the final PFL (361 +/- 118.7 mg/dl), which was measured after a mean of 24.1 +/- 11.7 hours with a mean tPA dose of 28.3 +/- 14.2 mg. The fibrinogen nadir was 327.6 +/- 107.1 mg/dl measured 13.4 +/- 10.3 hours after initiation of thrombolysis. Of patients with hemorrhagic complications (n = 6), initial, final, and nadir PFL were not significantly lower (P = .053, P = .081, and P = .086, respectively) than the remainder of the cohort. No significant difference was noted in initial and final PFL between the LMWH and UFH groups (P = .2 and P = .1, respe .lively) or between the CCDT and USAT groups (P = .5 and P = .9, respectively). The UFH group had a lower nadir PFL than the LMWH group (P = .03). Conclusions: Despite a significant drop in PFL during CDT for acute PE, this was not associated with hemorrhagic complications. These findings were not affected by the choice of anticoagulant or catheter delivery system.